glass cloth

Abstract

The present invention aims to provide a glass cloth having a ratio of a bending hysteresis 2HB in the weft direction to a bending stress B in the weft direction, i.e., a residual curvature 2HB / B of 0.5 (cm ‑1 ) or less, and a ratio of a shear hysteresis 2HG (gf / cm) in the weft direction to a shear stress G (gf / cm / deg) in the weft direction, i.e., a residual shear strain rate 2HG / G of 1.4 (deg ‑1 ) or less. A glass cloth is provided, which is a glass cloth constituted by a glass yarn including a plurality of glass long fibers as warp yarns and weft yarns, wherein at least a part of a surface of the glass long fiber includes (A) a polyalkylene oxide bisphenol A ether and (B) a silane coupling agent having an acryloyl group or a methacryloyl group, a warp yarn density and a weft yarn density of the glass cloth are 70 or more per 25 mm, and a carbon content of the glass cloth is 0.4 to 1.5 mass%.

Description

Technical Field

[0001] This invention relates to glass cloth and prepreg. Background Technology

[0002] Printed circuit boards and other laminated boards have an insulating layer and a conductor layer formed thereon. As the insulating layer, glass fiber reinforced resin, which is reinforced with a glass fiber substrate such as glass cloth, is usually used.

[0003] In recent years, the requirements for miniaturization and high performance of electronic components have become significant, and further miniaturization is also required in laminated circuit boards. Moreover, in order to meet these requirements, thin-film printed circuit boards and multilayer printed circuit boards have been developed, and thin-film glass cloth has been developed as the glass fiber used in them.

[0004] For example, Patent Document 1 describes a glass cloth that, even with an average layer count of less than 3.00, can suppress pinhole formation in prepregs using the glass cloth, and exhibits low fuzzing, thereby maintaining the excellent appearance quality of the prepreg. Specifically, Patent Document 1 describes a glass cloth composed of warp and weft yarns bundled together in groups of 14 to 55 long glass fibers with a diameter ranging from 3.0 to 4.2 μm. The weaving density of these warp and weft yarns is in the range of 86 to 140 yarns / 25 mm, and the thickness is in the range of 7.5 to 12.0 μm. 2 The average number of layers, expressed as (thickness of glass cloth / {(diameter of warp glass fibers + diameter of weft glass fibers) / 2}) for a mass ranging from 6.0 to 10.0 g, is in the range of 2.00 or higher and less than 3.00. This is calculated by dividing the thickness of the glass cloth by the average of the diameters of the warp and weft glass fibers. The average openness (where the number of warp fibers is the same as the warp fiber openness (where the warp fiber openness is the same as the weft ...

[0005] On the other hand, in order to improve the impregnation and adhesion of the prepreg and the matrix resin in the printed circuit board obtained from the prepreg to the glass cloth, the glass cloth is surface-treated with a silane coupling agent. As a glass cloth that has undergone this surface treatment, a surface-treated glass fiber fabric is known, comprising a glass fiber fabric and a treatment agent attached to the glass fiber fabric, said treatment agent containing a silane compound and a water-soluble polyurethane (for example, see Patent Document 2). According to this surface-treated glass fiber fabric, it is believed that a surface-treated glass fiber fabric with minimal mesh misalignment and sufficient rigidity, even when thinned, can be provided, as well as a method for manufacturing the same.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-21274

[0009] Patent Document 2: Japanese Patent Application Publication No. 2006-342445 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] In recent years, to meet the demands for miniaturization of electronic devices and the high-performance requirements of printed circuit boards (PCBs), the trend towards thinner prepregs and PCBs has continued. To achieve this thinning, thinner glass cloth is needed. Furthermore, due to the rapidly increasing demands for high-speed, high-capacity data transmission, there is a need for glass fibers used in prepregs and PCBs to have lower dielectric constants.

[0012] To form thin glass cloth, it is necessary to use warp and weft yarns containing glass fibers with smaller fiber diameters for weaving, and to flatten the warp and weft yarns through a fiber opening process.

[0013] In order to make the glass fiber have a low dielectric constant, low dielectric constant glass (such as NE glass, L glass, and LU glass manufactured by UNITIKA Co., Ltd.) is used as the glass material constituting the glass fiber.

[0014] Glass cloth made of thinner glass or glass with low dielectric constant has lower tensile strength and is more prone to breakage compared to glass cloth made of thicker general-purpose E glass.

[0015] 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 performed in the final process of the glass cloth. The surface treatment is performed by immersing a continuous glass cloth in the warp direction in a surface treatment agent containing a silane coupling agent, adjusting the amount of surface treatment agent adhering with clamping rollers, and then drying. The dried glass cloth is then wound into a glass cloth roll, and the glass cloth roll is rolled back and impregnated with a matrix resin to produce a prepreg.

[0016] Furthermore, the inventors conducted research and found that when manufacturing glass cloth with relatively low tensile strength, such as glass cloth with thin thickness or low dielectric constant glass, using the techniques of Patent Documents 1 and 2, if the warp tension of the glass cloth is kept relatively low during the final surface treatment process to prevent breakage, warp stripes (stripes extending along the length of the warp yarns) are easily generated on the wound glass cloth. Specifically, it was found that by reducing the warp tension, bending and undulation are generated in the weft direction (width direction) of the glass cloth during the surface treatment process. If the glass cloth is passed through the clamping roller in this bent and undulating state, it folds in the width direction, thereby generating warp stripes. If warp stripes are generated during the final surface treatment process, these warp stripes are directly carried into the prepreg manufacturing process, potentially affecting the quality of the prepreg.

[0017] Furthermore, the inventors conducted research and found that when manufacturing glass cloth with relatively low tensile strength, such as glass cloth using thin-thickness glass cloth or glass cloth with low dielectric constant, using the techniques of Patent Documents 1 and 2, a portion of the glass cloth may become skewed during winding (the weft yarn is not perpendicular to the warp yarn). Stress concentrates in the skewed portion, resulting in oblique wrinkles (wrinkles extending in a direction that is not parallel to the length direction of the warp yarn and not parallel to the length direction of the weft yarn) during winding. This phenomenon usually does not occur, for example, when using thicker glass cloth made of E-glass material. Moreover, if oblique wrinkles occur during winding in the surface treatment process, which is the final process, these oblique wrinkles are directly carried into the prepreg manufacturing process, potentially affecting the quality of the prepreg.

[0018] The inventors conducted further research and found that, in order to suppress the aforementioned warp stripes, it is important to set the ratio of the weft direction bending hysteresis 2HB to the weft direction bending stress B (i.e., residual curvature 2HB / B), obtained by using a pure bending tester as a texture measuring instrument under the conditions described later, to 0.5 (cm). -1The residual curvature 2HB / B is a value calculated from the bending hysteresis (2HB) and bending stiffness (B) obtained from the hysteresis curve of the bending characteristics measured by a pure bending testing machine. The residual strain is used to capture the energy loss during the process from bending deformation to recovery deformation, and the value of 2HB / B is used to quantify the restoring force. That is, the residual curvature 2HB / B can be understood as the residual strain during the process from bending deformation to recovery deformation; the smaller the residual strain, the higher the restoring force. The inventors have found that by setting the residual curvature 2HB / B to 0.5 (cm... -1 The following properties make it less prone to bending and undulation during the glass cloth manufacturing process, and it can easily prevent the formation of warp stripes when passing through the clamping rollers during the process.

[0019] Furthermore, the inventors conducted research and found that, in order to suppress the aforementioned oblique wrinkles, it is important to set the ratio of the "residual shear strain rate 2HG / G" (the ratio of the weft direction shear hysteresis 2HG (gf / cm) to the weft direction shear stress G (gf / cm / deg), obtained by using a tensile shear testing machine as a texture measuring instrument under the conditions described later, to 1.4 (deg). -1 The residual shear strain rate 2HG / G is a value 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. The residual strain captures the energy loss during the process from shear deformation to recovery deformation, and the value of 2HG / G quantifies the restoring force. That is, this value can be understood as capturing the residual strain during the process from shear deformation to recovery deformation; the smaller the residual strain, the higher the restoring force. The inventors discovered that by setting this residual shear strain rate to 1.4 (deg)... -1 The inherent strain in the glass cloth is easily mitigated during the surface treatment process and the formation of slanted wrinkles is easily prevented during winding.

[0020] Therefore, the main objective of this invention is to provide a glass cloth that solves the aforementioned problem, wherein the ratio of the bending hysteresis 2HB in the weft direction to the bending stress B in the weft direction, i.e., the residual curvature 2HB / B, is 0.5 (cm). -1 Below this value, and 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, i.e., the residual shear strain rate 2HG / G, is 1.4 (deg). -1 Below. Another objective of this invention is to provide a glass cloth that suppresses the generation of warp stripes and diagonal wrinkles.

[0021] Technical solutions for solving technical problems

[0022] The inventors have investigated the aforementioned problems. To reduce the residual curvature 2HB / B, it is necessary to reduce the bending hysteresis 2HB in the weft direction and increase the bending stiffness B. Furthermore, it has been 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 containing (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having acryloyl or methacryloyl groups to the glass cloth during the surface treatment process. Moreover, it has been found that increasing the adhesion amount of the surface treatment agent is effective in increasing the bending stiffness B.

[0023] Furthermore, to reduce the residual shear strain rate in the weft direction, it is necessary to reduce the shear hysteresis 2HG in the weft direction and increase the shear stress G in the weft direction. It has been found that, to reduce the shear hysteresis 2HG in the weft direction of the glass cloth, it is important to apply a surface treatment agent containing (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having acryloyl or methacryloyl groups to the glass cloth during the surface treatment process. Furthermore, it has been found that, to increase the shear stress G in the weft direction, it is important to ensure that the warp and weft densities of the glass cloth are above a certain value, thereby increasing the frictional force associated with the movement of interlacing points accompanied by shear deformation.

[0024] Furthermore, the inventors have discovered that in a glass cloth composed of glass yarn containing multiple long glass fibers as warp and weft yarns, at least a portion of the surface of the long glass fibers contains (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having acryloyl or methacryloyl groups, the warp and weft density of the glass cloth is set to 70 fibers / 25 mm or more, and the carbon content of the glass cloth is set to 0.4 to 1.5% by mass, thereby achieving a residual curvature 2HB / B of 0.5 (cm). -1 Below ) and the residual shear strain rate 2HG / G is 1.4 (deg) -1 The following can suppress the generation of meridional stripes and diagonal wrinkles.

[0025] This invention is the result of repeated and in-depth research based on this insight.

[0026] That is, the present invention provides an invention in the manner described below.

[0027] Item 1. A type of glass cloth, comprising glass yarn containing multiple long glass fibers as warp and weft yarns, wherein,

[0028] At least a portion of the surface of the glass fiber comprises (A) a polyoxyethylene bisphenol A ether and (B) a silane coupling agent having an acryloyl or methacryl group.

[0029] The warp and weft density of the glass cloth is 70 threads / 25mm or more.

[0030] The carbon content of the glass cloth is 0.4–1.5% by mass.

[0031] Item 2. The glass cloth according to Item 1, wherein the tensile strength in the warp direction is 20 to 120 N / 25 mm.

[0032] Item 3. The glass cloth according to item 1 or 2, wherein the thickness of the glass cloth is 5 to 30 μm.

[0033] Item 4. The glass cloth according to any one of items 1 to 3, wherein the glass cloth is a roll of glass cloth formed by winding glass cloth on a core.

[0034] Item 5. A prepreg comprising any one of items 1 to 4 glass cloth and a thermosetting resin contained in the glass cloth in a state of impregnation.

[0035] Invention Effects

[0036] According to the present invention, the glass cloth, by surface treatment with a specific surface treatment agent and by setting the weaving density and carbon content of the glass cloth within a specific range, can achieve a residual curvature of 2HB / B of 0.5 (cm). -1 Below ) and the residual shear strain rate 2HG / G is 1.4 (deg) -1 The following methods can effectively suppress the formation of meridional stripes and diagonal wrinkles. Attached Figure Description

[0037] Figure 1 (a) shows a schematic diagram of the determination of residual curvature 2HB / B using a pure bending tester. Figure 1 (b) shows an example of a bending hysteresis curve obtained using a pure bending tester.

[0038] Figure 2 (a) shows a schematic diagram of the determination of residual shear strain rate 2HG / G using a tensile shear testing machine. Figure 2 (b) shows an example of a shear hysteresis curve obtained using a tensile shear testing machine. Detailed Implementation

[0039] 1. Fiberglass cloth

[0040] The glass cloth of the present invention is a glass cloth composed of glass yarn containing multiple long glass fibers as warp and weft yarns. At least a portion of the surface of the long glass fibers contains (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having acryloyl or methacrylyl groups. The weaving density of the glass cloth is 70 fibers / 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.

[0041] [The glass yarn that makes up the glass cloth]

[0042] The glass cloth of the present invention uses glass yarn containing multiple long glass fibers as warp and weft yarns.

[0043] In the glass cloth of the present invention, there are no particular limitations on the glass material constituting the long glass fibers. Examples include E glass, T glass, S glass, UT glass, D glass, NE glass, L glass, LU glass (trade name), C glass, or AR glass manufactured by UNITIKA Co., Ltd.

[0044] From a general viewpoint, it is preferable to use glass yarn with an E-glass composition. The aforementioned E-glass composition comprises, relative to the total amount of glass fibers, 52-56% by mass of SiO2, 5-10% by mass of B2O3, 12-16% by mass of Al2O3, a total of 20-25% by mass of CaO and MgO, and a total of 0-1% by mass of Li2O, K2O, and Na2O.

[0045] Furthermore, from the viewpoint of further improving the strength of the prepreg and the printed circuit board, the glass yarn mentioned above is preferably a glass material comprising SiO2 in the range of 60 to 66% by mass, Al2O3 in the range of 20 to 26% by mass, and MgO in the range of 10 to 15% by mass relative to the total amount of glass fibers.

[0046] Furthermore, from the viewpoint of reducing the dielectric constant and dielectric loss tangent of the prepreg and printed circuit board, the glass yarn mentioned above preferably contains a glass material comprising 45-60% by mass of SiO2, 15-35% by mass of B2O3, 10-20% by mass of Al2O3, and 1-15% by mass of CaO relative to the total amount of glass fibers. More preferably, the glass material contains 45-55% by mass of SiO2, 20-35% by mass of B2O3, 10-20% by mass of Al2O3, and 3-10% by mass of CaO relative to the total amount of glass fibers.

[0047] It should be noted that the glass composition in this invention is determined by ICP emission spectrometry. Specifically, the Si and B contents can be obtained by dissolving a weighed glass cloth sample in sodium carbonate, then dissolving and bringing the volume to a constant with dilute nitric acid, and finally determining the composition by ICP emission spectrometry. Similarly, the Fe content can be obtained by dissolving a weighed glass cloth sample in an alkaline solution, bringing the volume to a constant, and then determining the composition by ICP emission spectrometry. Furthermore, the Al, Ca, and Mg contents can be obtained by heating a weighed glass cloth sample with sulfuric acid, nitric acid, and hydrogen fluoride, then dissolving and bringing the volume to a constant with dilute nitric acid, and finally determining the composition by ICP emission spectrometry. It should be noted that the Thermo Fisher iCAP6300Duo can be used as the ICP emission spectrometry apparatus.

[0048] In the glass cloth of the present invention, there is no particular limitation on the average fiber diameter of the long glass fibers. Examples of the average fiber diameter of the long glass fibers are 2 to 7 μm, but from the viewpoint of more easily exerting the effects of the present invention, 2.5 to 5.5 μm is preferred, and more preferably 3 to 5 μm.

[0049] Furthermore, in the glass cloth of the present invention, there is no particular limitation on the number of long glass fibers constituting the glass yarn. For example, 20 to 200 fibers can be cited, but from the viewpoint of more easily exerting the effect of the present invention, 20 to 100 fibers are preferred, and 20 to 50 fibers or 30 to 50 fibers are more preferred.

[0050] The average fiber diameter and number of glass fibers were measured and calculated as follows. Two pieces of glass cloth to be measured were prepared and cut into 30cm squares. One piece was used for observing the warp, and the other for observing the weft. They were then embedded in epoxy-based cold-embedded resin and allowed to cure. Next, the glass cloth embedded in the epoxy-based cold-embedded resin was ground to a level where the warp or weft could be observed. Using a SEM (Japanese Electronics Corporation, trade name JSM-6390A), observations were performed at a magnification of 2000x for the average fiber diameter and 500x for the number of fibers.

[0051] (1) Average fiber diameter of glass yarn (μm)

[0052] Randomly select 30 warp and 30 weft yarns respectively, observe the cross-section of the long fibers contained in each of the 30 glass yarns, measure the diameter, and calculate the average value as the average fiber diameter of the glass long fibers in the warp and weft yarns.

[0053] (2) Number of roots (roots)

[0054] Randomly select 30 warp and 30 weft yarns respectively, measure the number of long fibers contained in each of the 30 glass yarns, and calculate the average value as the number of warp and weft yarns.

[0055] Furthermore, in the glass cloth of the present invention, there is no particular limitation on the count of the glass yarn. For example, 0.5 to 25 tex can be cited, and from the viewpoint of more easily exerting the effect 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. It should be noted that in the present invention, the count of the glass yarn is a value determined and calculated according to the method specified in "7.1 Count" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers".

[0056] [Density and weave of the glass cloth]

[0057] The glass cloth of this invention has a warp and weft density of 70 yarns / 25mm or more. This increases the shear stress G in the weft direction of the glass cloth, making it easier to satisfy the residual shear strain rate 2HG / G of 1.4 (deg). -1 From the same viewpoint, the warp and weft densities are preferably 85 threads / 25mm or more. There are no particular upper limits for the warp and weft densities, but from the viewpoint of reducing the weight of the glass cloth, 130 threads / 25mm or less is preferred, and 120 threads / 25mm or less is more preferable. Specifically, warp and weft densities can be 70 to 130 threads / 25mm, and preferably 85 to 120 threads / 25mm. It should be noted that in this invention, the warp and weft densities are values ​​measured and calculated according to the method specified in "7.9 Density (Weaving Density)" of Japanese Industrial Standard JIS R 3420-2013 "General Test Methods for Glass Fibers".

[0058] It should be noted that glass cloth is manufactured under greater tension on the warp yarns than on the weft yarns. Therefore, the weft yarns of the glass cloth are manufactured under weaker tension, resulting in greater unevenness in yarn width when viewed from the plane than the warp yarns. Therefore, in this invention, the weft yarn can also be defined as the glass cloth yarn with the greater unevenness in yarn width when viewed from the plane compared to the warp yarns.

[0059] There are no particular restrictions on the fabric structure of glass cloth; for example, plain weave, satin weave, twill weave, square plain weave, and ribbed weave can be used. Among these, plain weave is preferred.

[0060] Surface treatment of glass cloth

[0061] The glass cloth of the present invention comprises at least a portion of (A) a polyoxyethylene bisphenol A ether and (B) a silane coupling agent having an acryloyl or methacrylyl group on the surface of the long glass fibers. By including these, the bending hysteresis 2HB in the weft direction of the glass cloth can be reduced, resulting in a residual curvature 2HB / B of 0.5 (cm). -1 Below that. Furthermore, by including them, the shear hysteresis 2HG in the weft direction of the glass cloth can be reduced, resulting in a residual shear strain rate 2HG / G of 1.4 (deg). -1 )the following.

[0062] Polyoxyethylene bisphenol A ether refers to the compound represented by the following general formula (1).

[0063] [Chemistry 1]

[0064]

[0065] In general formula (1), R 1 and R 2 "Same" or "different" indicates an alkylene group. The number of carbon atoms in an alkylene group can be, for example, 2 to 4, preferably 2 or 3, more preferably 2. In general formula (1), n 1 and n 2 This represents the average number of moles of olefin oxide added. As n... 1 and n 2 Examples of values ​​include 2 to 50, preferably 4 to 30, and more preferably 6 to 20. 1 and n 2 These can be different values ​​or approximately the same value. As one method of polyoxyethylene bisphenol A ether, R in general formula (1) can be cited as an example. 1 and R 2 are the same alkylene group, and n 1 and n 2 The values ​​are approximately the same for polyoxyethylene bisphenol A ether.

[0066] The polyoxyethylene bisphenol A ether used in this invention is preferably polyoxyethylene bisphenol A ether or polyoxypropylene bisphenol A ether. From the viewpoint of superior lubricity and easier reduction of fiberglass cloth fuzzing, polyoxyethylene bisphenol A ether is more preferred. The average molar number of added olefins in the polyoxyethylene bisphenol A ether used in this invention is, for example, 2 to 40, preferably 4 to 30, and more preferably 6 to 20. Here, the average molar number of added olefins in the polyoxyethylene bisphenol A ether refers to the average of the total number of olefins contained in the two polyoxyethylene chains constituting the polyoxyethylene bisphenol A ether.

[0067] Examples of silane coupling agents having an acryloyl or methacryloyl group include compounds represented by the following general formula (2).

[0068] [Chemistry 2]

[0069] CH2=CR 3 -CO-OR 4 -SiR 5 m (OR 6 ) 3-m (2)

[0070] In general formula (2), R 2 Represents a hydrogen atom or a methyl group. In general formula (2), R 4 It is an alkylene group having 1 to 6 carbon atoms. As R 4 Examples of suitable alkylene compounds include alkylene compounds with 1 to 4 carbon atoms, more preferably alkylene compounds with 2 to 4 carbon atoms, and even more preferably alkylene compounds with 3 carbon atoms. 4 The alkylene group can be either straight-chain or branched, preferably branched. In general formula (2), R 5 and R 6 Each alkyl group, having 1 to 5 carbon atoms, is represented independently. As R 5 and R 6 Examples of alkyl groups with 1 to 3 carbon atoms are preferred, more preferably alkyl groups with 1 or 2 carbon atoms, and even more preferably methyl. In general formula (2), m represents an integer of 0 or more and 2 or less. Examples of m include 0 or 1, more preferably 0.

[0071] As a silane coupling agent having an acryloyl or methacryloyl group, specifically, examples include: 3-acryloyloxypropyltrimethoxysilane (in general formula (2), R 3 For H, R 4 =-C3H6-, m is 0, R 6 Compounds of type -CH3), 3-methacryloyloxypropyltrimethoxysilane (in general formula (2), R 3 -CH3, R 4 =-C3H6-, m is 0, R 6 Compounds of type -CH3), 3-acryloyloxypropylmethyldimethoxysilane (in general formula (2), R 3 For H, R 4 -C3H6-, m = 1, R 5 and R 6 Compounds of type -CH3), 3-methacryloyloxypropylmethyldimethoxysilane (in general formula (2), R 3 -CH3, R 4 -C3H6-, m = 1, R 5 and R 6Compounds of type -CH3), 3-acryloyloxypropyltriethoxysilane (in general formula (2), R 3 For H, R 4 =-C3H6-, m is 0, R 6 Compounds of type -C2H5), 3-methacryloyloxypropyltriethoxysilane (in general formula (2), R 3 -CH3, R 4 =-C3H6-, m is 0, R 6 Compounds with a -C2H5 group, etc. Among them, 3-acryloyloxypropyltrimethoxysilane and 3-methacryloyloxypropyltrimethoxysilane are preferred.

[0072] In the glass cloth of the present invention, the ratio of (A) polyoxyethylene bisphenol A ether to (B) a silane coupling agent having an acryloyl group or a methacryloyl 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, relative to 100 parts by mass of the total amount of (A) polyoxyethylene bisphenol A ether.

[0073] Furthermore, in the glass cloth of the present invention, the mass ratio of (A) polyoxyethylene bisphenol A ether as a component relative to the total amount of 100 parts by mass of the components attached to the surface of the long 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.

[0074] Furthermore, in the glass cloth of the present invention, the mass ratio of (B) a silane coupling agent having an acryloyl group or a methacryloyl group, which is 100 parts by mass relative to the total amount of the components attached to the surface of the long glass fibers, is, for example, 10 to 90 parts by mass, preferably 20 to 80 parts by mass.

[0075] In the glass cloth of the present invention, at least a portion of the surface of the long glass fibers may contain a silane coupling agent other than (B) a silane coupling agent having an acryloyl or methacryloyl group. Examples of silane coupling agents other than (B) a silane coupling agent having an acryloyl or methacryloyl group include amino-based silane coupling agents, vinyl-based silane coupling agents, phenyl-based silane coupling agents, epoxypropoxy-based silane coupling agents, isocyanate-based silane coupling agents, mercapto-based silane coupling agents, styrene-based silane coupling agents, and urea-based silane coupling agents. In particular, the combined use of (B) a silane coupling agent having an acryloyl or methacryloyl group and a silane coupling agent having an amino or vinyl group is preferred because it more easily improves the adhesion to the matrix resin when preparing the prepreg.

[0076] Examples of silane coupling agents having an organic functional group containing an amino group include compounds represented by the following general formula (3) and their salts.

[0077] [Chemistry 3]

[0078] X-SiR 7 p (OR 8 ) 3-p (3)

[0079] In general formula (3), X represents an organic functional group having one or more amino groups. In general formula (3), p represents an integer of 0 or more and 2 or less. Examples of p include 0 or 1, more preferably 0. In general formula (3), R 7 and R 8 Each alkyl group, having 1 to 5 carbon atoms, is represented independently. As R 7 and R 8 Examples of alkyl groups are preferably alkyl groups having 1 to 3 carbon atoms, and more preferably alkyl groups having 1 or 2 carbon atoms.

[0080] As silane coupling agents containing amino groups, examples include monomeric 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, and γ-(2-aminoethyl)aminopropyltriethoxysilane, or mixtures thereof. More preferably, 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, and N-β-(N-benzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride.

[0081] Examples of silane coupling agents having vinyl or styrene groups include compounds represented by the following general formula (4).

[0082] [Chemical Formula 4]

[0083] Y-SiR 9 q (OR 10 ) 3-q (4)

[0084] In general formula (4), Y represents an organic functional group containing one or more vinyl or styrene groups. In general formula (4), R 9 It is an alkyl group having 1 to 8 carbon atoms, preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, or tert-butyl. Additionally, in general formula (4), OR 10 The alkoxy group is an alkoxy group with 1 to 8 carbon atoms that may have substituents, preferably methoxy, ethoxy, or methoxyethoxy. In general formula (4), q is an integer from 0 to 2, preferably 0.

[0085] Specific examples of silane coupling agents having vinyl or styrene groups include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, and styrenetrimethoxysilane.

[0086] In the glass cloth of the present invention, the mass ratio of the total amount of silane coupling agent relative to 100 parts by mass of the total amount of the component attached to the surface of the long 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 refers to the combined mass of (B) silane coupling agent having acryloyl or methacryloyl groups and other silane coupling agents included as needed.

[0087] Furthermore, in the glass cloth of the present invention, the mass ratio of (B) silane coupling agent having acryloyl or methacryloyl groups to 100 parts by mass of the total amount of silane coupling agent attached to the surface of the long glass 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 refers to the combined mass of (B) silane coupling agent having acryloyl or methacryloyl groups and other silane coupling agents included as needed.

[0088] Furthermore, in the glass cloth of the present invention, at least a portion of the surface of the long glass fibers may contain a softener, an antistatic agent, or a surfactant, as needed. The softener, antistatic agent, and surfactant may be appropriately selected according to the type of surface treatment agent used.

[0089] [Properties of glass cloth, etc.]

[0090] The carbon content of the glass cloth of the present invention is 0.4 to 1.5% by mass. This carbon content serves as an indicator of the amount of surface treatment agent adhering to the surface, which comprises (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having acryloyl or methacryloyl groups. By setting the carbon content within the above range, the flexural stiffness B can be effectively improved, and the residual curvature 2HB / B can be made to be 0.5 (cm). -1From the viewpoint of more easily improving the adhesion between the prepreg and the matrix resin, the carbon content is more preferably 0.5 to 1.2% by mass, and more preferably 0.6 to 1.1% by mass. In this invention, the carbon content is a value determined according to the following steps. First, using a total carbon measuring device, the glass cloth is burned and reduced under oxygen cycling at a reaction temperature of 850°C and a reduction temperature of 600°C, and the total organic carbon obtained by column chromatography separated from porous polymer beads is quantified using a thermal conductivity detector (TCD). Next, the carbon content of the glass cloth is calculated using a standard curve prepared using acetanilide as an elemental quantitative standard sample.

[0091] In the glass cloth of the present invention, there are no particular limitations on the loss on ignition, for example: 0.2 to 1.5% by mass, preferably 0.5 to 1.5% by mass, more preferably 1.0 to 1.4% by mass, and even more preferably 1.05 to 1.3% by mass. In the present invention, the loss on ignition is a value determined according to the method specified in "7.3.2 Loss on Ignition" of Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers".

[0092] There are no particular limitations on the quality of the glass cloth used in this invention; for example, 5 to 50 g / m² can be cited. 2 Preferably 5-30 g / m 2 More preferably 5-20 g / m 2 In this invention, the quality of the glass cloth is determined according to the method specified in "7.2 Quality (mass) of cloth and pad" of Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers".

[0093] The thickness (μm) of the glass cloth in this invention is not particularly limited, and examples include 5 to 50 μm, preferably 5 to 30 μm, and more preferably 9 to 25 μm. In this invention, the thickness of the glass cloth is measured using an electronic micrometer with a minimum display value of 0.001 mm, according to Method B specified in "7.10.1 Thickness of Cloth" of Japanese Industrial Standard JIS R3420:2013 "General Test Methods for Glass Fibers".

[0094] 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. It should be noted that the above tensile strength is obtained by the following method: according to the method specified in "7.4.2 Fabric Case" of Japanese Industrial Standard JIS R3420:2013 "General Test Methods for Glass Fibers", a constant speed elongation type tensile testing machine is used. The length of the test piece is set to 25 cm, the width of the test piece (width before untying the yarn at both ends) is set to 30 mm, the clamping interval is set to 15 cm, the width of the test piece (width after untying the yarn at both ends) is set to 25 mm, and the constant speed elongation is set to 200 mm / min. For the warp direction of the glass cloth, the tensile strength is measured 5 times, and the average value is taken as the tensile strength (N / 25 mm) in the warp direction of the glass cloth.

[0095] It should be noted that in the manufacture of glass cloth, the tufting agent and paste required during the weaving of warp and weft yarns undergo degreasing treatment. This degreasing treatment is called a hot cleaning treatment. The tensile strength of the glass cloth after this hot cleaning treatment is reduced to less than half compared to that before the hot cleaning treatment. Moreover, the preferred range of tensile strength mentioned above, 20 to 120 N / 25 mm, indicates that the tensile strength of the glass cloth after the hot cleaning treatment is significantly different from that of the glass cloth without the hot cleaning treatment.

[0096] The glass cloth of the present invention comprises a glass cloth consisting of glass yarn containing multiple long glass fibers as warp and weft yarns, wherein at least a portion of the surface of the long glass fibers contains (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having acryloyl or methacrylyl groups. The glass cloth has a weaving density of 70 fibers / 25 mm or more and a carbon content of 0.4 to 1.5% by mass. Based on this, a residual curvature 2HB / B of 0.5 cm can be achieved. -1 The residual shear strain rate 2HG / G is 1.4 (deg). -1 Below that, as a more preferred range for the residual curvature 2HB / B of the glass cloth of the present invention, 0.1 cm is an example. -1 Above and 0.5cm -1 The following is more preferably 0.2cm -1 Above and 0.45cm -1 The following is a further description. Furthermore, a more preferred range for the residual shear strain rate 2HG / G of the glass cloth of the present invention is 0.1 deg. -1 Above and 1.4deg -1 The following is more preferably 0.5deg -1 Above and 1.2deg -1 The following is a further preferred value of 0.7deg. -1Above and 1.1deg -1 the following.

[0097] 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. Hereinafter, refer to... Figure 1 The method for determining the residual curvature 2HB / B of glass cloth is explained. Figure 1 The left figure in (a) is a schematic diagram of the state of glass cloth being bent into an arc shape using a pure bending tester. Figure 1 The right figure in (a) is a schematic representation of the bending moment (M) generated when 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 samples of glass cloth cut to 20cm x 20cm are prepared and overlapped with their warp and weft yarns aligned in the same direction, serving as the test sample. It should be noted that if the warp and weft yarns in the glass cloth cannot be immediately distinguished, as described above, it is sufficient to determine that the side with the greater unevenness in yarn width when viewed from the plane corresponds to the weft yarn. The test sample is fixed with a chuck spacing of 1cm. During fixing, the sample is wound evenly around the chuck from both ends along the length of the weft yarn (i.e., the direction of continuous weft yarn). Then, as... Figure 1 As shown in (a), the weft yarn moves at a uniform speed (deformation speed (0.5)). -1 The curve is bent into an arc until the curvature K = +2.5cm. -1 Then the weft yarn moves at a uniform speed (deformation speed (0.5)). -1 The curve bends in the opposite direction until it reaches its maximum curvature of -2.5cm. -1 After restoration, a bending test is performed to measure the bending moment generated along with the change in curvature. Figure 1 (a)). The bending test consists of one cycle, and the bending characteristic value is obtained as follows. Figure 1 (b) shows the bending hysteresis curve (vertical axis: bending moment, horizontal axis: curvature). From this bending hysteresis curve, calculate the bending stiffness B (gf·cm) per unit length. 2 / cm) and the hysteresis width 2HB (gf·cm / cm). This measurement was conducted at 23°C and 50% RH. It should be noted that in this invention, the bending stiffness B per unit length is taken as the bending stiffness at curvature K = +0.5cm. -1 Up to +1.5cm -1 The average inclination of the differential value of the bending moment (M) measured between intervals, with the lag width 2HB as the curvature K = +1.0 cm. -1 The hysteresis width in the middle (refer to) Figure 1(b)) This can be calculated. For example, the measurement can be performed using 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 was performed five times using 10 different glass cloth samples, and the average value of the ratio of the bending hysteresis 2HB in the weft direction to the bending stress B in the weft direction, i.e., the residual shear strain rate 2HB / B, was obtained.

[0098] 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. Hereinafter, refer to... Figure 2 The method for determining the residual shear strain rate 2HG / G of glass cloth is explained. Figure 2 (a) is to use a tensile shear testing machine to shear the glass cloth to the shear angle. A diagram illustrating the state. Figure 2 (b) is an example of a shear hysteresis curve obtained using a tensile shear testing machine. First, prepare two samples of glass cloth cut to 20cm x 20cm. Overlap these two samples with their warp and weft yarns aligned in the same direction to serve as the test sample. It should be noted that if the warp and weft yarns in the glass cloth cannot be immediately distinguished, as described above, it is sufficient to determine that the side with the greater unevenness in yarn width when viewed from the plane corresponds to the weft yarn. Fix the test sample with a chuck spacing of 5cm. During fixing, the sample is wound evenly around the chuck from both ends along the length of the weft yarn (i.e., the direction of continuous weft yarn). Then, as... Figure 2 As shown, under a forced load (W) of 10 gf / cm applied to the length direction of the weft yarn (i.e., the direction in which the weft yarn is continuous), the warp yarn is deformed at a uniform speed (0.00834° / sec) to the shear angle in the length direction of the warp yarn (i.e., the direction in which the warp yarn is continuous). Then deform in the opposite direction to the shear angle Afterwards, the system was restored to its original state, and the shear force generated along with the change in shear angle was measured (refer to...). Figure 2 (a)). The shear test consisted of one cycle, and the shear characteristic value was obtained as follows. Figure 2 (b) shows the shear hysteresis curve (vertical axis: shear force, horizontal axis: shear angle). Based on this shear hysteresis curve, the shear stress G (gf / cm / deg) in the weft direction and the hysteresis width 2HG (gf / cm) are calculated. This measurement was conducted at 23°C and 50% RH. It should be noted that the shear stress G per unit length is taken as the value at the shear angle. The average inclination of the differential value of the shear force (Fs) measured between +2.5, with the hysteresis width 2HG as the shear angle. The width of the time lag (refer to) Figure 2 (b)) This measurement can be performed, for example, using the KES-FB SYSTEM (Ver. 7.18WJ) data measurement program, and the KES-FB CALC (Ver. 7.07J) data calculation program to calculate G and 2HG. The above measurement was performed five times using 10 different glass cloth samples, and the average value of 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, i.e., the residual shear strain rate 2HG / G, was obtained.

[0099] [Method for manufacturing glass cloth]

[0100] Next, an example of the manufacturing method of the glass cloth of the present invention will be described. First, a glass cloth is woven, in which glass yarn containing multiple long glass fibers is used as both warp and weft. Any conventionally known method can be used for weaving; for example, after performing a warping and sizing process on the warp yarns, the weft yarns can be driven in using a jet loom (e.g., an air-jet loom, water-jet loom, etc.), a Sulzer loom, a rapier loom, etc.

[0101] Then, fiber opening treatment and / or hot cleaning treatment can be performed as needed. Examples of fiber opening treatment methods include fiber opening using water pressure on the obtained glass cloth, fiber opening using high-frequency vibration with water (e.g., degassed water, ion-exchanged water, deionized water, electrolyzed cation water, or electrolyzed anion water) as the medium, and processing under pressure using rollers. This fiber opening treatment can be performed simultaneously with or after weaving. Furthermore, the fiber opening treatment can be performed before or after hot cleaning treatment, or simultaneously with the surface treatment described later, or after the surface treatment described later. Additionally, as a method for adjusting the degree of fiber opening of the warp and weft yarns, known methods can be used, such as adjusting the warp tension; using a pinch expander, bending rubber roller, rotating sliding roller, Miravo roller, or tenter frame in the weft direction to adjust and balance the tension in the warp and weft directions while performing fiber opening; or combining these methods.

[0102] When the woven glass cloth is coated with substances (such as bridging agents) that hinder the adhesion and impregnation of the matrix resin during the production of prepregs and printed circuit boards, it is preferable to remove these substances, for example, by heat cleaning. It should be noted that for glass cloth woven from glass yarn to which the surface treatment agent described later has been applied in the first and second stages of the paste, the heat cleaning process may be omitted. As for the temperature conditions for the heat cleaning process, 350°C or higher is preferred, 350–500°C is more preferred, and 380–450°C is even more preferred. Furthermore, the heat cleaning time can be appropriately set according to the temperature conditions used. For example, when the glass cloth is made into a roll (a product in which the glass cloth is wound around a core), and the heat cleaning process is performed in the roll state, 20–60 hours, preferably 24–48 hours, and even more preferably 24–36 hours are examples of times the heat cleaning time can be achieved.

[0103] Then, in the method for manufacturing the glass cloth of the present invention, the prepared glass cloth is subjected to surface treatment. As a surface treatment, firstly, a treatment agent is prepared.

[0104] The prepared treatment agent comprises components and solvents that adhere to the surface of the long glass fibers. Specifically, it is a treatment agent comprising (A) a polyoxyethylene bisphenol A ether and / or (B) a silane coupling agent having an acryloyl or methacryl group, and a solvent. There are no particular limitations on the type of solvent; water is an example.

[0105] There are no particular limitations on the content of (A) polyoxyethylene bisphenol A ether in the treatment agent, for example, 1 to 30 g / L, preferably 2 to 20 g / L, and more preferably 3 to 15 g / L. Furthermore, there are no particular limitations on the content of (B) silane coupling agent having an acryloyl or methacryl group in the treatment agent, for example, 3 to 40 g / L, preferably 5 to 35 g / L, and more preferably 10 to 30 g / L.

[0106] The mass ratio of (A) polyoxyethylene bisphenol A ether as part of the total non-volatile components contained in the treatment agent is not particularly limited, for example, 10-90% by mass, preferably 20-80% by mass, more preferably 10-50% by mass, and even more preferably 15-45% by mass. The mass ratio of (B) silane coupling agents having acryloyl or methacryloyl groups as part of the total non-volatile components contained in the treatment agent is not particularly limited, for example, 10-90% by mass, preferably 20-80% by mass. Furthermore, the mass ratio of total silane coupling agents as part of the total non-volatile components contained in the treatment agent is not particularly limited, for example, 10-90% by mass, preferably 40-90% by mass, and more preferably 45-85% by mass. Furthermore, the proportion of the total mass of silane coupling agents having acryloyl or methacryloyl groups relative to 100 parts by mass of the total silane coupling agent contained in the treatment agent is not particularly limited; for example, 10 to 100 parts by mass are possible, preferably 30 to 100 parts by mass, and more preferably 50 to 100 parts by mass. It should be noted that in this invention, "non-volatile components" refers to the oven-dry components that remain after heat treatment at 110°C under normal pressure to remove solvents and the like, reaching a constant weight; these are the components that ultimately adhere to the surface of the long glass fibers in the glass cloth of this invention and remain thereafter.

[0107] The glass cloth can be surface-treated by impregnating, coating, or spraying it with a prepared treatment agent, followed by drying. In the surface treatment process, the prepared glass cloth can be treated by applying and drying the treatment agent as a mixture of (A) and (B) mentioned above, or by applying and drying the treatment agent (A) and (B) separately in two stages.

[0108] [Forms and uses of fiberglass cloth]

[0109] In one embodiment of the glass cloth of the present invention, a roll of long strip glass cloth is provided, on which the glass cloth is wound around a core. When the glass cloth of the present invention is a roll of long strip glass cloth, there are no particular limitations on the length and width of the glass cloth; 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.

[0110] The glass cloth of the present invention is suitable as a fiber substrate for prepregs. In particular, the glass cloth of the present invention is especially suitable as a fiber substrate for prepregs used in printed circuit boards. Prepregs using the glass cloth of the present invention will be described later.

[0111] 2. Prepreg

[0112] The prepreg of the present invention comprises the glass cloth and a thermosetting resin contained in the glass cloth in a state of impregnation.

[0113] As a thermosetting resin, there are no particular limitations on any resin that is cured by heat. Examples include phenolic resins, epoxy resins, non-halogenated epoxy resins, cyanate ester resins, maleimide resins, bismaleimide resins, modified bismaleimide resins, isocyanate resins, benzocyclobutene resins, vinyl resins, bismaleimide triazine resins, phenolic resins, and thermosetting polyphenylene ether resins. A single thermosetting resin can be used, or two or more can be used in combination.

[0114] Furthermore, the prepreg of the present invention may contain inorganic fillers. Examples of inorganic fillers include silica-based materials 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, and LU glass as glass materials).

[0115] The prepreg of the present invention is suitable for use as a constituent material of printed circuit boards.

[0116] Example

[0117] The present invention will now be described in detail with examples and comparative examples. However, the present invention is not limited to the examples.

[0118] 1. Measurement and Evaluation Methods

[0119] 1-1. Average fiber diameter and number of glass fibers

[0120] The average fiber diameter of the glass fibers and the number of glass fibers constituting the glass yarn were determined as follows. Specifically, two pieces of glass cloth were prepared, each cut into 30cm squares. One piece was used for observing the warp, and the other for observing the weft. These pieces were then embedded in an epoxy-based cold-embedding resin (manufactured by Struers Co., Ltd., trade name: Epoxy Resin Specialix-40) and allowed to cure. Next, the glass cloth embedded in the epoxy-based cold-embedding resin was ground to a level where the warp or weft could be observed. The average fiber diameter was observed at 2000x magnification and the number of fibers at 500x magnification using a scanning electron microscope (SEM) (manufactured by Nippon Electron Co., Ltd., trade name: JSM-6390A).

[0121] (1) Average fiber diameter (μm) of glass long fibers

[0122] For each of the warp and weft yarns, 30 yarns are randomly selected. The cross-section of the long fibers contained in each of the 30 glass yarns is observed and the diameter is measured. The average value is calculated as the average fiber diameter of the glass long fibers in the warp and weft yarns.

[0123] (2) Number of long glass fibers (strands)

[0124] For each of the warp and weft yarns, 30 yarns are randomly selected, and the total number of long fibers contained in each of the 30 yarns is measured and the average value is calculated as the number of long glass fibers in the warp and weft yarns.

[0125] 1-2. Weaving density of glass cloth

[0126] The weaving density of the glass cloth was determined according to the method specified in "7.9 Density (Weaving Density)" of Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers". Specifically, the measurement object was a position 50 mm or more from the end and edge of the glass cloth, and the measurement interval was set to be 10 mm or more and 200 mm or less. The total number of yarns within the set measurement interval was measured. This was considered as one measurement. The measurement was then performed twice more at other positions excluding the yarns measured previously, using the same method. After every three measurements, the number of yarns per 25 mm was calculated using the following formula, and the average of the three measurements was calculated.

[0127] [Number 1]

[0128] Mi = (ni / ai) × 25

[0129] Mi: Number of yarn ends per 25mm

[0130] ni: The number of yarn ends measured

[0131] ai: The correct distance (mm) to be measured.

[0132] 1-3. Count of glass yarn

[0133] The count of the glass yarn in the glass cloth was determined according to the method specified in "7.1 Count" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers". Specifically, firstly, 500m of glass yarn was collected from a yarn winding device and made into a test piece. The test piece was placed flat in a muffle furnace and fired at 625°C for 25 minutes. After cooling in a desiccator, the mass of the test piece was measured. The count was calculated according to the following formula.

[0134] [Number 2]

[0135] t = (m / 500) × 1000

[0136] t: number of branches

[0137] m: Mass of the test piece (g)

[0138] 1-4. Quality of glass cloth

[0139] The quality of the glass cloth was determined according to the method specified in "7.2 Quality (mass) of cloth and pad" of Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers". Specifically, a sample of 100 cm² area was taken from a point at least 50 mm from the edge of the glass cloth. 2 A square test piece was dried at 105℃ for 1 hour, and the mass of the test piece was measured. The mass of each 1m³ was calculated using the following formula. 2 The quality.

[0140] [Number 3]

[0141] ρA=(ms / 100)×10 4

[0142] ρA: per 1m 2 mass (g / m 2 )

[0143] ms: Mass of the test piece (g)

[0144] 1-5. Thickness of the glass cloth

[0145] The thickness of the glass cloth was measured according to Method B, "7.10.1 Thickness of Cloth," of Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers." Specifically, the thickness was measured at the inner part of the cloth at a distance of 50 mm or more from both ends and the edges using an electronic micrometer with a minimum display value of 0.001 mm.

[0146] 1-6. Weight loss on ignition of glass cloth

[0147] The loss on ignition of the glass cloth was determined according to the method specified in "7.3.2 Loss on Ignition" of Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers". Specifically, a 100cm section was cut from the inner side at least 10mm from the corner or end. 2The above test pieces were placed in a desiccator at 105°C and dried for 30 minutes. After drying, the test pieces were transferred to a desiccator and cooled to room temperature, and their mass was measured. The drying, cooling, and measurement processes were repeated until the mass became constant, and the mass of the dried test pieces was determined. Next, the dried test pieces were placed in a muffle furnace adjusted to 625°C and heated for at least 10 minutes. After removing the test pieces from the muffle furnace, they were transferred to a desiccator and cooled, and their mass was measured. The heating, cooling, and measurement processes were repeated until the mass became constant, and the mass of the dried and heated test pieces was determined. The loss on ignition (%) was calculated using the following formula.

[0148] [Number 4]

[0149] H2=(m1-m2) / m1×100

[0150] H2: Loss on ignition (%)

[0151] m1: Mass of the dried test piece (g)

[0152] m2: Mass of the test piece after drying and heating (g)

[0153] 1-7. Tensile strength of glass cloth

[0154] The tensile strength of the glass cloth was measured according to the method specified in "7.4.2 Cloth Case" of "General Test Methods for Glass Fibers" in Japanese Industrial Standard JIS R 3420:2013. A constant speed elongation tensile testing machine (manufactured by Intesco Co., Ltd.) was used. The length of the test piece was set to 25 cm, the width of the test piece (width before untying the yarn at both ends) was set to 30 mm, the clamping interval was set to 15 cm, the width of the test piece (width after untying the yarn at both ends) was set to 25 mm, and the constant speed elongation was set to 200 mm / min. The breaking strength was measured 5 times in the warp direction of the glass cloth, and the average value of the measured values ​​was taken as the tensile strength of the glass cloth (N / 25 mm).

[0155] 1-8. Carbon content of glass cloth

[0156] Using a total carbon assay apparatus (manufactured by Sumika Chemical Analysis Service, Ltd., SUMIGRAPH (registered trademark) NCH-22F), glass cloth was subjected to combustion and reduction under oxygen cycling at a reaction temperature of 850°C and a reduction temperature of 600°C. The total organic carbon obtained by column chromatography using porous polymer beads was quantified using a thermal conductivity detector (TCD). The carbon content of the glass cloth was calculated using a standard curve prepared with acetanilide as the elemental standard.

[0157] 1-9. Uneven width of warp and weft yarns

[0158] To determine the unevenness of yarn width, the glass cloth was cut into 20cm x 20cm pieces. Using an optical microscope, the width of one warp yarn was randomly selected. For each of the three warp yarns, the width was measured at 1cm intervals along the length of the yarn. This measurement was repeated 18 times at 1cm intervals along the length of the yarn, for a total of 19 measurements. The coefficient of variation (CV) (standard deviation / mean) of the yarn width at these 19 measurements was calculated. This measurement was performed on the three warp yarns, and the average CV value of the three warp yarns was calculated. The same method was used to calculate the CV value of the weft yarn. A larger CV value indicates greater unevenness in yarn width.

[0159] 1-10. Residual curvature 2HB / B

[0160] The residual curvature 2HB / B was measured using a KES-FB2 pure bending tester manufactured by Kato Tech Co., Ltd. Specifically, two pieces of glass cloth cut to 20cm x 20cm were prepared and overlapped with their warp and weft yarns aligned in the same direction to form the test sample. The test sample was fixed with a chuck spacing of 1cm. During fixing, the sample was wound evenly around the chuck from both ends along the length of the weft yarn. Then, as... Figure 1 As shown in (a), the weft yarn moves at a uniform speed (deformation speed (0.5)). -1 The curve is bent into an arc until the curvature K = +2.5cm. -1 Then the weft yarn moves at a uniform speed (deformation speed (0.5)). -1 The curve bends in the opposite direction until it reaches its maximum curvature of -2.5cm. -1 After restoration, a bending test is performed to measure the bending moment generated along with the change in curvature. Figure 1 (a)). The bending test consists of one cycle, and the bending characteristic value is obtained. Figure 1 (b) shows the bending hysteresis curve. Calculate the bending stiffness B (gf·cm) per unit length. 2 / cm) and the hysteresis width 2HB (gf·cm / cm). This measurement was performed at 23°C and 50% RH. It should be noted that in this invention, B is the curvature K = +0.5cm. -1 Up to +1.5cm -1 The average inclination of the differential values ​​of the bending moment (M) measured between the two points, 2HB is taken as the curvature K = +1.0 cm. - The hysteresis width in 1 (refer to) Figure 1(b) was calculated. In this experiment, measurements were performed using the KES-FB SYSTEM (Ver. 7.18WJ) data measurement program, and B and 2HB were calculated using the KES-FB CALC (Ver. 7.07J) data calculation program. The above measurements were performed five times using 10 different glass cloth samples, and the average value of the residual shear strain rate 2HB / B was obtained.

[0161] 1-11. Residual shear strain rate 2HG / G

[0162] The residual shear strain rate, 2 HG / G, was measured using a Kato Tech KES-FB1 tensile shear testing machine. Specifically, two pieces of glass cloth, each cut to 20 cm × 20 cm, were prepared and overlapped with their warp and weft yarns aligned in the same direction. The test samples were then fixed with a chuck spacing of 5 cm. During fixing, the sample was wound evenly around the chuck from both ends along the length of the weft yarn. Then, as... Figure 2 As shown, under the condition that a forced load (W) of 10 gf / cm is applied to the length direction of the weft yarn (i.e., the direction in which the weft yarn is continuous), the warp yarn is deformed at a uniform speed (0.00834° / sec) to the shear angle in the length direction of the warp yarn (i.e., the direction in which the warp yarn is continuous). Then deform in the opposite direction to the shear angle Afterwards, the system was restored to its original state, and the shear force generated along with the change in shear angle was measured (refer to...). Figure 2 (a)). The shear test consisted of one cycle, and the shear characteristic value was obtained. Figure 2 (b) shows the shear hysteresis curve. The shear stress G (gf / cm / deg) in the weft direction and the hysteresis width 2HG (gf / cm) were then calculated. This measurement was conducted at 23°C and 50% RH. It should be noted that G is the shear angle. The average inclination of the derivative of the shear force (Fs) measured between +2.5, where 2HG is the shear angle. The width of the time lag (refer to) Figure 2 (b) was calculated. In this measurement, the KES-FB SYSTEM (Ver. 7.18WJ) data measurement program was used, and the KES-FB CALC (Ver. 7.07J) data calculation program was used to calculate G and 2HG. The above measurement was performed 5 times using 10 different glass cloth samples, and the average value of the residual shear strain rate 2HG / G was obtained.

[0163] 1-12. Evaluation of the level of warp stripe formation in glass cloth

[0164] For the obtained glass cloth, a random visual inspection was conducted on a length of 1000m to observe the number of warp stripes. The number of warp stripes generated per 100m length was calculated, and the evaluation was performed according to the following criteria. It should be noted that warp stripes are counted for stripes longer than 100cm.

[0165] A: The number of meridional fringes generated is 0.0 per 100m.

[0166] B: The number of meridional fringes is 0.1 to 0.5 per 100m.

[0167] C: The number of meridional fringes exceeds 0.6 per 100m.

[0168] 1-13. Evaluation of whether or not diagonal wrinkles occur in the glass cloth

[0169] For the obtained glass cloth, a random visual inspection was conducted on a length of 1000m to observe the number of diagonal wrinkles and evaluate the presence or absence of diagonal wrinkles. It should be noted that diagonal wrinkles are counted as wrinkles longer than 10cm.

[0170] A: No oblique folds were observed.

[0171] B: The number of oblique folds observed.

[0172] 2. Manufacturing of glass cloth

[0173] Example 1

[0174] As warp and weft yarns, glass yarn containing long glass fibers is used. These long glass fibers are composed of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 51 wt%, Al2O3: 13 wt%, CaO: 8 wt%, B2O3: 23 wt%, and the balance 5 wt%. The average fiber diameter is 4.0 μm, and the fiber count is 100 fibers. The glass yarn is woven using an air-jet loom to obtain a plain weave glass cloth roll (a long strip of glass cloth wound around a core) with a warp density of 75 fibers / 25 mm and a weft density of 76 fibers / 25 mm. The resulting glass cloth roll is then heated at an atmospheric temperature of 400°C for 30 hours to perform a heat cleaning treatment. No warp stripes or diagonal wrinkles are generated in the heat-cleaned glass cloth.

[0175] Next, the treatment agent of Formula 1 is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 1.

[0176] (Formula 1)

[0177] N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by JNC Corporation, trade name Sila-Ace (registered trademark) S-350, non-volatile component 30%): 9.0 g / L

[0178] 3-Methacryloxypropyltrimethoxysilane (manufactured by JNC Corporation, trade name Sila-Ace (registered trademark) S-710, non-volatile content 98%): 13.5 g / L

[0179] Polyoxyethylene bisphenol A ether (manufactured by Yoshimura Oil Chemical Co., Ltd., trade name GF690, non-volatile component 70%): 5.2 g / L

[0180] Balance: Pure water

[0181] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the length of the warp yarns (the direction of continuous warp yarns) while being impregnated with the treatment agent of Formula 1, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing a high-pressure spray fiber-opening treatment, they are again impregnated in the treatment agent of Formula 1, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0182] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 96 N / 25 mm, and 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 weight loss on ignition was 1.16% by mass, and the carbon content was 0.72% by mass.

[0183] [Example 2]

[0184] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers were composed of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 51 wt%, Al2O3: 13 wt%, CaO: 8 wt%, B2O3: 23 wt%, and the balance 5 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 100 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 fibers / 25 mm and a weft density of 76 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0185] Next, the treatment agent of Formula 2 is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 1.

[0186] (Formula 2)

[0187] 3-Methacryloxypropyltrimethoxysilane (manufactured by JNC Corporation, trade name Sila-Ace (registered trademark) S710, non-volatile content 98%): 6.75 g / L

[0188] Vinyltrimethoxysilane (manufactured by JNC Corporation, trade name Sila-Ace (registered trademark) S210, non-volatile content 99%): 6.0 g / L

[0189] Polyoxyethylene bisphenol A ether (manufactured by Yoshimura Oil Chemical Co., Ltd., trade name GF690, non-volatile component 70%): 15.7 g / L

[0190] Polyalkylene polyamine fatty acid amide (trade name KSK-2240, manufactured by Lion Specialty Chemicals Co., Ltd., non-volatile component 30%): 5.0 g / L

[0191] Balance: Pure water

[0192] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 2, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 2, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0193] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 81 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.36 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 0.94 (deg). -1 The weight loss on ignition was 1.25% by mass, and the carbon content was 0.96% by mass.

[0194] [Example 3]

[0195] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 51 wt%, Al2O3: 13 wt%, CaO: 8 wt%, B2O3: 23 wt%, and the balance 5 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 100 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 fibers / 25 mm and a weft density of 76 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0196] Next, the treatment agent of Formula 3 is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 1.

[0197] (Formula 3)

[0198] 3-Methacryloxypropyltrimethoxysilane (manufactured by JNC Corporation, trade name Sila-Ace (registered trademark) S-710, non-volatile content 98%): 13.5 g / L

[0199] Polyoxyethylene bisphenol A ether (manufactured by Yoshimura Oil Chemical Co., Ltd., trade name GF690, non-volatile component 70%): 5.2 g / L

[0200] Balance: Pure water

[0201] The glass cloth that has undergone heat cleaning is subjected to a tension of 150 N / m along the length of the warp yarns, while being impregnated in the treatment agent of Formula 3, with a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 3, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0202] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 84 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.34 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 1.02 (deg). -1 The weight loss on ignition was 1.10% by mass, and the carbon content was 0.65% by mass.

[0203] [Example 4]

[0204] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 49 wt%, Al2O3: 14 wt%, CaO: 6 wt%, B2O3: 28 wt%, and the balance 3 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 50. The glass yarn was woven using 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 resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0205] Next, the treatment agent of Formula 1 above is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 1.

[0206] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 1, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 1, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0207] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 49 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.40 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 0.96 (deg). -1 The weight loss on ignition was 1.13% by mass, and the carbon content was 0.64% by mass.

[0208] [Example 5]

[0209] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 49 wt%, Al2O3: 14 wt%, CaO: 6 wt%, B2O3: 28 wt%, and the balance 3 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 50. The glass yarn was woven using 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 resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0210] Next, the treatment agent of Formula 2 above is prepared as a surface treatment agent. It should be noted that the composition ratio of the non-volatile components of the treatment agent is shown in Table 1.

[0211] The glass cloth that has undergone heat cleaning is subjected to a tension of 150 N / m along the length of the warp yarns while being immersed in the treatment agent of Formula 2, with a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 2, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0212] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 50 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.43 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 0.93 (deg). -1 The weight loss on ignition was 1.35% by mass, and the carbon content was 1.06% by mass.

[0213] [Example 6]

[0214] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 49 wt%, Al2O3: 14 wt%, CaO: 6 wt%, B2O3: 28 wt%, and the balance 3 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 50. The glass yarn was woven using 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 resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0215] Next, the treatment agent of Formula 3 above is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0216] The glass cloth that has undergone heat cleaning is subjected to a tension of 150 N / m along the length of the warp yarns, while being impregnated in the treatment agent of Formula 3, with a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 3, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0217] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 52 N / 25 mm, and 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 1.07 (deg). -1 The weight loss on ignition was 1.06% by mass, and the carbon content was 0.70% by mass.

[0218] [Example 7]

[0219] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 50 wt%, Al2O3: 15 wt%, CaO: 5 wt%, B2O3: 27 wt%, and the balance 3 wt%. The average fiber diameter was 4.0 μm, and the fiber count was 40 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 fibers / 25 mm and a weft density of 95 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0220] Next, the treatment agent of Formula 1 above is prepared as a surface treatment agent. It should be noted that the composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0221] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 1, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 1, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0222] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 36 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.44 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 0.89 (deg). -1 The weight loss on ignition was 1.17% by mass, and the carbon content was 0.80% by mass.

[0223] [Example 8]

[0224] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 50 wt%, Al2O3: 15 wt%, CaO: 5 wt%, B2O3: 27 wt%, and the balance 3 wt%. The average fiber diameter was 4.0 μm, and the fiber count was 40 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 fibers / 25 mm and a weft density of 95 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0225] Next, the treatment agent of Formula 2 above is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0226] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 2, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 2, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0227] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 36 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.49 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 0.89 (deg). -1 The weight loss on ignition was 1.30% by mass, and the carbon content was 0.92% by mass.

[0228] [Example 9]

[0229] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 50 wt%, Al2O3: 15 wt%, CaO: 5 wt%, B2O3: 27 wt%, and the balance 3 wt%. The average fiber diameter was 4.0 μm, and the fiber count was 40 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 fibers / 25 mm and a weft density of 95 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0230] Next, the treatment agent of Formula 3 above is prepared as a surface treatment agent. It should be noted that the composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0231] The glass cloth that has undergone heat cleaning is subjected to a tension of 150 N / m along the length of the warp yarns, while being impregnated in the treatment agent of Formula 3, with a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 3, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0232] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 39 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.49 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 1.01 (deg). -1 The weight loss on ignition was 1.18% by mass, and the carbon content was 0.66% by mass.

[0233] [Example 10]

[0234] As warp and weft yarns, glass yarn containing long glass fibers was used. These fibers consisted of E-glass comprising: SiO2: 54 wt%, Al2O3: 14 wt%, CaO: 23 wt%, MgO: 1 wt%, B2O3: 6 wt%, and the balance 2 wt%, with an average fiber diameter of 3.6 μm and a fiber count of 38. The glass yarn was woven using 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 resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0235] Next, the treatment agent of Formula 1 above is prepared as a surface treatment agent. It should be noted that the composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0236] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 1, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 1, using 35 N / cm... 2The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0237] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 51 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.48 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 1.03 (deg). -1 The weight loss on ignition was 0.61% by mass, and the carbon content was 0.73% by mass.

[0238] [Comparative Example 1]

[0239] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 51 wt%, Al2O3: 13 wt%, CaO: 8 wt%, B2O3: 23 wt%, and the balance 5 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 100 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 fibers / 25 mm and a weft density of 76 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0240] Next, the treatment agent of Formula 4 is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0241] (Formula 4)

[0242] N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by JNC Corporation, trade name Sila-Ace (registered trademark) S-350, non-volatile component 30%): 9.0 g / L

[0243] Trimethoxyphenylsilane (DuPont Toray Specialty Material Co., Ltd., trade name Z6124, 90% non-volatile component): 14.7g / L

[0244] Balance: Pure water

[0245] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 4, using a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 4, using 35 N / cm...2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0246] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 96 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.34 (cm). -1 The residual shear strain rate in the weft direction, 2HG / G, is 2.96 (deg). -1 The weight loss on ignition was 0.99% by mass, and the carbon content was 0.43% by mass.

[0247] [Comparative Example 2]

[0248] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 51 wt%, Al2O3: 13 wt%, CaO: 8 wt%, B2O3: 23 wt%, and the balance 5 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 100 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 fibers / 25 mm and a weft density of 76 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0249] Next, the treatment agent of Formula 5 is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0250] (Formula 5)

[0251] N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by JNC Corporation, trade name Sila-Ace (registered trademark) S-350, non-volatile component 30%): 9.0 g / L

[0252] Balance: Pure water

[0253] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 5, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 5, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0254] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 78 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.62 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 1.83 (deg). -1 The weight loss on ignition was 0.63% by mass, and the carbon content was 0.14% by mass.

[0255] [Comparative Example 3]

[0256] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 51 wt%, Al2O3: 13 wt%, CaO: 8 wt%, B2O3: 23 wt%, and the balance 5 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 100 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 fibers / 25 mm and a weft density of 76 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0257] Next, the treatment agent of Formula 6 is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0258] (Formula 6)

[0259] N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by JNC Corporation, trade name Sila-Ace (registered trademark) S-350, non-volatile component 30%): 3.0 g / L

[0260] Polyoxyethylene bisphenol A ether (manufactured by Yoshimura Oil Chemical Co., Ltd., trade name GF690, non-volatile component 70%): 5.2 g / L

[0261] Balance: Pure water

[0262] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 6, using a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 6, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0263] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 92 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 1.42 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 1.09 (deg). -1 The weight loss on ignition was 0.85% by mass, and the carbon content was 0.24% by mass.

[0264] [Comparative Example 4]

[0265] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 49 wt%, Al2O3: 14 wt%, CaO: 6 wt%, B2O3: 28 wt%, and the balance 3 wt%, with an average fiber diameter of 4.0 μm and a fiber count of 50. The glass yarn was woven using 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 resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0266] Next, the treatment agent of Formula 5 above is prepared as a surface treatment agent. It should be noted that the composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0267] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 5, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 5, using 35 N / cm... 2 The glass cloth is obtained by pressing the clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0268] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 53 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.58 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 1.79 (deg). -1 The weight loss on ignition was 0.65% by mass, and the carbon content was 0.12% by mass.

[0269] [Comparative Example 5]

[0270] As warp and weft yarns, glass yarn containing long glass fibers was used. These long glass fibers consisted of a low dielectric constant and low dielectric loss tangential glass material comprising: SiO2: 50 wt%, Al2O3: 15 wt%, CaO: 5 wt%, B2O3: 27 wt%, and the balance 3 wt%. The average fiber diameter was 4.0 μm, and the fiber count was 40 fibers. The glass yarn was woven using an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 fibers / 25 mm and a weft density of 95 fibers / 25 mm. The resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0271] Next, the treatment agent of Formula 5 above is prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0272] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 5, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spray fiber opening treatment, they are again impregnated in the treatment agent of Formula 5, using 35 N / cm... 2 The glass cloth is obtained by pressing it with clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0273] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 30 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.56 (cm). -1 The residual shear strain rate 2HG / G in the weft direction is 1.63 (deg). -1 The weight loss on ignition was 0.65% by mass, and the carbon content was 0.12% by mass.

[0274] [Comparative Example 6]

[0275] As warp and weft yarns, glass yarn containing long glass fibers was used. These fibers consisted of E-glass comprising: SiO2: 54 wt%, Al2O3: 14 wt%, CaO: 23 wt%, MgO: 1 wt%, B2O3: 6 wt%, and the balance 2 wt%, with an average fiber diameter of 3.6 μm and a fiber count of 38. The glass yarn was woven using 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 resulting glass cloth roll was then subjected to a heat cleaning treatment by heating it at an atmospheric temperature of 400°C for 30 hours. No warp stripes or diagonal wrinkles were generated in the heat-cleaned glass cloth.

[0276] Next, the treatment agent of Formula 5 above is prepared as a surface treatment agent. It should be noted that the composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0277] The heat-cleaned glass cloth was subjected to a tension of 150 N / m along the warp length while being impregnated with the treatment agent of Formula 5, and then subjected to a tension of 35 N / cm. 2 The fibers are squeezed by clamping rollers under clamping pressure and dried at 120°C. Next, after undergoing high-pressure spraying for fiber opening, they are again impregnated in the treatment agent of Formula 5, and sprayed with 35 N / cm... 2 The glass cloth is obtained by pressing it with clamping rollers under clamping pressure and drying it at a temperature of 120°C.

[0278] The obtained glass cloth exhibits greater yarn width unevenness in the weft direction than in the warp direction. The tensile strength in the warp direction is 43 N / 25 mm, and the residual curvature 2HB / B in the weft direction is 0.79 (cm). -1 The residual shear strain rate in the weft direction, 2HG / G, is 1.59 (deg). -1 The weight loss on ignition was 0.23% by mass, and the carbon content was 0.21% by mass.

[0279] 3. Results

[0280] For each glass cloth, the average fiber diameter and number of long glass fibers contained in the glass yarn, weaving density, yarn count, weight, thickness, weight loss on ignition, tensile strength and carbon content, residual curvature 2HB / B, residual shear strain rate 2HG / G, the formation of warp stripes, and the formation of oblique wrinkles were evaluated. The evaluation results are shown in Tables 1, 2, and 3.

[0281] [Table 1]

[0282]

[0283] [Table 2]

[0284]

[0285] [Table 3]

[0286]

[0287] The glass cloths in Examples 1-10 are glass cloths constructed by using glass yarn containing multiple long glass fibers as warp and weft yarns. At least a portion of the surface of the long glass fibers contains (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having acryloyl or methacrylyl groups. The weaving density of the glass cloth is 70 fibers / 25 mm or more, and the carbon content of the glass cloth is 0.4-1.5% by mass. Therefore, a residual curvature 2HB / B of 0.5 (cm) can be obtained. -1 Below ) and the residual shear strain rate 2HG / G is 1.4 (deg) -1 The glass cloths described in Examples 1-10 are as follows. Furthermore, the glass cloths described in Examples 1-10 are able to suppress the generation of longitudinal wrinkles and diagonal wrinkles.

[0288] On the other hand, although the glass cloth of Comparative Example 1 has a carbon content of 0.4% by mass or more, at least a portion of the surface of the glass long fibers does not contain (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having acryloyl or methacryloyl groups, therefore the residual shear strain rate 2HG / G exceeds 1.4 (deg). -1 Furthermore, the glass cloth of Comparative Example 1 could not suppress the formation of diagonal wrinkles.

[0289] Furthermore, the glass cloths of Comparative Examples 2, 4-6 have a carbon content of less than 0.4% by mass, and at least a portion of the surface of the long glass fibers does not contain (A) polyoxyethylene bisphenol A ether and (B) a silane coupling agent having an acryloyl or methacryl group. Therefore, the residual curvature 2HB / B exceeds 0.5 (cm). -1 Furthermore, the residual shear strain rate 2HG / G exceeds 1.4 (deg). -1 Furthermore, the glass cloths used in Comparative Examples 2, 4-6 could not suppress the formation of longitudinal stripes and diagonal wrinkles.

[0290] The glass cloth of Comparative Example 3 has a carbon content of less than 0.4% by mass, and at least a portion of the surface of the long glass fibers does not contain (B) a silane coupling agent having an acryloyl or methacryloyl group; therefore, the residual shear strain rate 2HG / G exceeds 1.4 (deg). -1 Furthermore, the glass cloth of Comparative Example 3 could not suppress the generation of longitudinal stripes.

Claims

1. A glass cloth, characterized by, It is a glass cloth made by using glass yarn containing multiple long glass fibers as both warp and weft yarns. The glass cloth is a glass cloth that has undergone heat cleaning and surface treatment with a treatment agent. The treatment agent comprises (A) a polyoxyethylene bisphenol A ether and (B) a silane coupling agent having an acryloyl or methacryl group, as well as a solvent. At least a portion of the surface of the glass fiber comprises (A) the polyoxyethylene bisphenol A ether and (B) the silane coupling agent having an acryloyl or methacryl group. The warp and weft density of the glass cloth is 70 threads / 25mm or more. The carbon content of the glass cloth is 0.4 to 1.5 by mass.

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

3. The glass cloth of claim 1, wherein, The thickness of the glass cloth is 5–30 μm.

4. The glass cloth according to any one of claims 1 to 3, wherein, The glass cloth is a roll of long strip glass cloth formed by winding glass cloth on a core.

5. A prepreg, characterized by, The glass cloth comprising any one of claims 1 to 4 and the thermosetting resin contained therein in the state of being impregnated with the glass cloth.

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