Rolled long glass cloth and prepreg

Abstract

To provide a roll-type long glass cloth with minimal breakage and fuzzing over long lengths, and a roll-type long prepreg containing the glass cloth. [Solution] According to this disclosure, a roll-shaped long glass cloth wound on a core tube and a roll-shaped long prepreg containing the glass cloth are provided. The glass cloth is composed of glass threads made of a plurality of glass filaments as warp and weft threads, the roll-shaped long glass cloth has a tensile strength variation ratio Sb / Sa of 0.6 or more, where Sa is the larger of the tensile strength of the inner layer and the tensile strength of the outer layer of the roll-shaped long glass cloth, and Sb is the smaller of the two values, the outer layer is located at a position of 4% to 6% from the unwinding point relative to the winding amount L (m) of the glass cloth, and the inner layer is located at a position of 94% to 96%.

Description

[Technical Field]

[0001] This disclosure relates to rolled, long glass cloth and prepregs, etc. [Background technology]

[0002] Currently, electronic devices are becoming more high-performance and smaller. Against this backdrop, printed circuit boards (PCBs) are seeing increased density and integration of wiring. For example, in semiconductor package substrate applications, there is a demand not only for improved heat resistance but also for reduced warping, such as further reduction of thermal expansion in insulating materials. Similarly, there is a demand for reduced thermal expansion in prepregs used as insulating materials in PCBs, as well as in the glass yarn and glass cloth contained within the prepregs.

[0003] As a means of improving thermal expansion, for example, a method of preparing a prepreg using low thermal expansion glass cloth is known (see Patent Document 1).

[0004] After weaving, glass cloth is typically treated with an organic binder for surface protection to suppress fuzzing of the glass fibers. The woven glass cloth then undergoes a heat de-oiling process to burn off the binder, followed by surface treatment with a silane coupling agent or the like to produce a product for printed circuit board applications. This heat de-oiling process is generally carried out using a batch heating method, where the glass cloth is heated in a roll wound around a metal core (Patent Document 2).

[0005] It is generally known that the metal on the winding core side expands more easily with heat than the glass cloth. Patent document 2 describes using a winding core made of an alloy with a smaller coefficient of thermal expansion than glass cloth in order to prevent breakage and fraying of the glass cloth near the outer surface that occurs when a metal winding core expands toward the outer surface during heating. Patent document 3 also describes using a winding core made of quartz glass or ceramics, which have a small coefficient of thermal expansion. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-46517 [Patent Document 2] Japanese Patent Publication No. 2001-199640 [Patent Document 3] Japanese Patent Publication No. 2014-122446 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Patent Document 2 describes that when a metal winding core expands toward the outer circumference during heating, damage occurs to the glass cloth near the outer surface, causing breakage and fraying (paragraph 0003). Thus, conventionally, it has been thought that damage to the glass cloth during the heat de-oiling process occurs near the outer surface due to the thermal expansion of the winding core. In this regard, the present inventors have found that even if the thermal expansion of the winding core is reduced by means such as those disclosed in Patent Documents 2 and 3, and the damage to the glass cloth near the outer surface is reduced, damage occurs to the inner layer side (winding core side) of the glass cloth wound on the winding core during heat de-oiling, making it impossible to obtain a glass cloth roll with less breakage and fraying over a long length, and that this tendency is particularly pronounced in low thermal expansion glass cloth.

[0008] Therefore, one of the objectives of this disclosure is to provide a roll-shaped long glass cloth that exhibits minimal breakage and fuzzing over long lengths, and to provide a roll-shaped long prepreg containing the glass cloth. Furthermore, in other embodiments, this disclosure aims to provide a winding core for heat-de-oiling the glass cloth and a heat-de-oiling method for suitably obtaining the above-mentioned glass cloth. [Means for solving the problem]

[0009] Some embodiments of this disclosure are illustrated in the following sections [1] to

[28] . [1] A roll-shaped long glass cloth wound around a core tube, wherein the glass cloth is composed of glass yarns made of a plurality of glass filaments as warp and weft, in the roll-shaped long glass cloth, the ratio Sb / Sa of the variation in tensile strength is 0.6 or more, where Sa is the larger value of the tensile strength of the glass cloth located in the inner layer of the roll-shaped long glass cloth and the tensile strength of the glass cloth located in the surface layer, and Sb is the smaller value of the tensile strength of the glass cloth located in the inner layer of the roll-shaped long glass cloth and the tensile strength of the glass cloth located in the surface layer. The surface layer is at a position of 4% or more and 6% or less from the unwinding with respect to the winding amount L (m) of the glass cloth, and the inner layer is at a position of 94% or more and 96% or less from the unwinding with respect to the winding amount L (m) of the glass cloth. Roll-shaped long glass cloth. [2] The roll-shaped long glass cloth according to item 1, wherein the bulk CTE of the glass constituting the glass cloth is 5 ppm / K or less. [3] The roll-shaped long glass cloth according to item 1, wherein the bulk CTE of the glass constituting the glass cloth is 3.0 ppm / K or less. [4] The roll-shaped long glass cloth according to item 1, wherein the bulk CTE of the glass constituting the glass cloth is 2.7 ppm / K or less. [5] The roll-shaped long glass cloth according to any one of items 1 to 4, wherein the bulk elastic modulus of the glass constituting the glass cloth is 60 GPa or more. [6] The roll-shaped long glass cloth according to any one of items 1 to 5, wherein the glass cloth is treated with a surface treatment agent containing a silane coupling agent. [7] The silane coupling agent is represented by the following formula (1): X(R) 3-n SiY n ···(1) A roll of glass cloth as described in item 6, comprising a compound represented by {Formula (1), where X is an organic group having at least one of an amino group and a radically reactive unsaturated double bond group, Y is independently an alkoxy group, n is an integer between 1 and 3, and R is independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group.}. [8] A roll-shaped long glass cloth according to any one of items 1 to 7, wherein the carbon content of the glass cloth is in the range of 0.01% by mass to 1.0% by mass. [9] The roll-shaped long glass cloth described in any one of items 1 to 8, wherein the absolute value of the difference in carbon content of the glass cloth |Ca-Cb| is 0.028 mass% or less, where Ca is the amount of carbon content in the surface layer of the roll-shaped long glass cloth, Cb is the amount of carbon content in the inner layer of the roll-shaped long glass cloth, the surface layer is located at a position of 4% to 6% from the unwinding point relative to the winding length L(m) of the glass cloth, and the inner layer is located at a position of 94% to 96% from the unwinding point relative to the winding length L(m) of the glass cloth.

[10] A roll-shaped long glass cloth according to any one of items 1 to 9, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a tensile strength of 15 N / 25 mm or more.

[11] The roll-shaped long glass cloth described in any one of items 1 to 10, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer have a tensile strength per unit thickness of 1.1 N / 25 mm / μm or more, which is determined by dividing the tensile strength by the thickness.

[12] A roll-shaped long glass cloth according to any one of items 1 to 11, wherein the bulk CTE of the glass constituting the glass cloth is 0.1 ppm / K or more.

[13] A roll-shaped long glass cloth according to any one of items 1 to 11, wherein the bulk CTE of the glass constituting the glass cloth is 1.0 ppm / K or more.

[14] A roll-shaped long glass cloth according to any one of items 1 to 13, wherein the thickness of the glass cloth is 120 μm or less.

[15] A roll-shaped long glass cloth according to any one of items 1 to 14, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a dielectric loss tangent value of 0.0080 or less at 10 GHz.

[16] The roll-shaped long glass cloth according to any one of items 1 to 15, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a dielectric loss tangent value of 0.0060 or less at 10 GHz.

[17] A roll-shaped long glass cloth according to any one of items 1 to 15, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a dielectric loss tangent value of 0.0042 or less at 10 GHz.

[18] The roll-shaped long glass cloth described in any one of items 1 to 17, wherein the absolute value of the dielectric loss tangent difference of the glass cloth at 10 GHz, |Dfa-Dfb|, is 0.0004 or less, where Dfa is the dielectric loss tangent of the surface layer of the roll-shaped long glass cloth at 10 GHz, Dfb is the dielectric loss tangent of the inner layer of the roll-shaped long glass cloth at 10 GHz, the surface layer is located at a position of 4% to 6% from the unwinding point relative to the winding amount L(m) of the glass cloth, and the inner layer is located at a position of 94% to 96% from the unwinding point relative to the winding amount L(m) of the glass cloth.

[19] One or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a lightness (L * A roll of long glass cloth described in any one of items 1 to 18, with a value of 88 or higher.

[20] In the aforementioned roll-shaped long glass cloth, the absolute value of the brightness difference of the glass cloth is |L * aL *b| is less than or equal to 1.5, where L * a is the lightness of the surface layer of the rolled long glass cloth, and L * b is the brightness of the inner layer of the rolled long glass cloth, the surface layer is located at a position of 4% to 6% from the unwinding point relative to the winding amount L(m) of the glass cloth, and the inner layer is located at a position of 94% to 96% from the unwinding point relative to the winding amount L(m) of the glass cloth, as described in any one of items 1 to 19. [twenty one] The roll-shaped long glass cloth described in any one of items 1 to 20, wherein the tensile strength variation ratio Sb / Sa is less than 1.0. [twenty two] A roll of long glass cloth described in any one of items 1 to 21, with a winding length of 500m or more. [twenty three] A roll of long glass cloth for use in printed circuit boards, as described in any one of items 1 to 22. [twenty four] A roll-shaped long prepreg comprising a roll-shaped long glass cloth described in any one of items 1 to 23 and a matrix resin impregnated in the glass cloth. [twenty five] A winding core for heat-degreasing glass cloth, made of a material with a thermal expansion coefficient of 14 ppm / K or less at 0-100°C, and with an outer diameter of Φ500 mm or more at the winding section.

[26] A method for manufacturing roll-shaped long glass cloth as described in any one of items 1 to 23, wherein the method is: Heating and degreasing the glass cloth, This includes cooling the glass cloth after the heat degreasing process, A method for manufacturing glass cloth that satisfies either or both of the following conditions (i) or (ii). (i) The heat degreasing is performed with the glass cloth wound around a core made of a material having a coefficient of thermal expansion of 14 ppm / K or less at 0 to 100°C and having an outer diameter of Φ500 mm or more at the winding portion. (ii) The cooling rate of the glass cloth in the above cooling is 70°C / h or less.

[27] A method for manufacturing glass cloth as described in item 26, satisfying the conditions of (i) above.

[28] A method for manufacturing glass cloth as described in item 26 or 27, which satisfies the conditions of (ii) above. [Effects of the Invention]

[0010] According to this disclosure, it is possible to provide a roll-shaped long glass cloth with minimal breakage and fuzzing over long lengths, and a roll-shaped long prepreg containing the glass cloth. Furthermore, according to other embodiments of this disclosure, it is possible to provide a winding core for heat de-oiling of glass cloth and a heat de-oiling method for suitably obtaining the above-mentioned glass cloth. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure are described below. The present invention is not limited to embodiments of this disclosure, and various modifications are possible without departing from the spirit of the invention. In this disclosure, numerical ranges indicated using "~" include the numbers before and after "~" as the lower and upper limits. In this disclosure, in numerical ranges described in steps, the upper or lower limit indicated in one numerical range may be replaced with the upper or lower limit of another numerical range described in steps. In this disclosure, the upper or lower limit indicated in one numerical range may also be replaced with the values ​​shown in the examples. In this disclosure, the term "process" is included not only in the sense of an independent process, but also in the sense of a process that is not clearly distinguishable from other processes, as long as the function of the process is achieved.

[0012] 《Long rolls of glass cloth》 The roll-shaped long glass cloth of this disclosure is a roll-shaped long glass cloth wound around a core tube, and is composed of glass threads containing multiple filaments as warp and weft threads, and the tensile strength variation ratio Sb / Sa of the roll-shaped long glass cloth is 0.6 or more. Here, Sa is the larger of the tensile strengths of the glass cloth located in the surface layer and the inner layer of the roll-shaped long glass cloth, and Sb is the smaller of the tensile strengths of the glass cloth located in the surface layer and the inner layer of the roll-shaped long glass cloth.

[0013] Conventionally, it was believed that when the winding core expands toward the outer circumference during heating, damage occurs to the glass cloth near the outer surface, causing breakage and fraying. Therefore, damage to the inner layer of glass cloth was not given particular consideration. However, as a result of our investigations, we have found that the methods described in Patent Documents 2 and 3 have room for improvement in obtaining long rolls of low-thermal-expansion glass cloth with minimal breakage and fraying over long lengths. In this disclosure, "long length" is not particularly limited, but preferably means a winding length L of 500m or more. The upper limit of the winding length L is not particularly limited, but may be 5000m or less.

[0014] While not limited to theory, the inventors diligently investigated the suppression of breakage and fuzzing over long lengths of glass cloth and found that a change in the tensile strength of the cloth in the longitudinal direction is one of the contributing factors. Furthermore, they discovered that not only is damage to the outer circumference of the roll during thermal expansion in the heating and de-oiling process a concern, but the tightening of the winding on the inner layer of the roll during cooling and shrinkage also damages the glass cloth on the inner layer, significantly increasing the change in the tensile strength of the cloth in the longitudinal direction. Moreover, they found a method to control the change in tensile strength in the longitudinal direction within a predetermined range, making it possible to suppress breakage and fuzzing over long lengths.

[0015] More specifically, in the heat de-oiling process of glass cloth, stronger winding occurs on the inner layer side of the roll during cooling shrinkage compared to the outer periphery side. After the protective agent is burned off by heat de-oiling, the glass cloth becomes brittle and susceptible to damage from external forces such as winding tightening. In addition, the circumferential stress decreases, making it prone to winding wrinkles, which are difficult to eliminate and can lead to a decrease in glass strength. It is generally known that after the heat de-oiling process, glass cloth is subjected to continuous surface treatment processes while being transported. Typically, in such continuous processing, processing conditions, such as transport tension, are standardized for each roll. In glass cloth rolls, if there is a large difference in tensile strength in the longitudinal direction, using transport tension matched to the high-tensile strength areas makes the low-tensile strength areas prone to breakage and fuzzing. Conversely, using transport tension matched to the low-tensile strength areas results in insufficient tension in the high-tensile strength areas, causing wrinkles and fuzzing. Therefore, controlling the difference in tensile strength in the longitudinal direction within a predetermined range makes it possible to suppress breakage and fuzzing. Because glass cloth with low thermal expansion is hard, wrinkles that form during winding are particularly difficult to eliminate, and a decrease in glass strength is likely to occur. Therefore, the effects of this disclosure become more pronounced when using glass cloth with low thermal expansion.

[0016] The roll-shaped long glass cloth of this disclosure is not limited to a specific manufacturing method, but in order to control the variation ratio of tensile strength within a predetermined range, it is preferable to use a winding core with a small coefficient of thermal expansion in the heat de-oiling process, or to use a winding core with a large outer diameter in the heat de-oiling process. In addition, the core tube in the roll-shaped long glass cloth as a product is generally different from the winding core used in the heat de-oiling process, however, the same one may be used for both. Furthermore, the variation ratio of tensile strength can also be adjusted by controlling the cooling rate after the completion of the heat de-oiling process, and bending of the mesh can also be suppressed by controlling the cooling rate.

[0017] <Coefficient of thermal expansion of glass (CTE)> The bulk CTE of the glass used in the glass cloth of this disclosure is preferably 5 ppm / K or less. By using such low thermal expansion glass yarn, the resulting glass cloth can be made to have low thermal expansion, making it easier to reduce warping of prepregs and printed circuit boards. Furthermore, when low thermal expansion glass yarn is used, breakage, fuzzing, and distortion due to winding tightening during the heating and de-oiling process of the glass cloth are significantly reduced, and a suppression effect is easily obtained. From the viewpoint of reducing thermal expansion, the bulk CTE is preferably 3.3 ppm / K or less, more preferably 3.0 ppm / K or less, even more preferably 2.8 ppm / K or less, and particularly preferably 2.7 ppm / K or less. Furthermore, from the viewpoint of suppressing breakage, fuzzing, and distortion, and from the viewpoint of suppressing streaks where the threads are spaced apart in a planar manner, the bulk CTE is preferably 0.1 ppm / K or more, more preferably 1.0 ppm / K or more, even more preferably 1.5 ppm / K or more, and even more preferably 2.0 ppm / K or more. When the bulk CTE is low, the glass tends to harden, and hard glass is prone to not only creases that create relatively three-dimensional irregularities, but also streaks. If the bulk CTE is 0.1 ppm / K or higher, creases are more easily eliminated, and the decrease in strength is more easily suppressed. In addition, streaks are less likely to occur, and appearance defects are more easily suppressed in glass cloth and prepregs.

[0018] <Bulk modulus of glass> The bulk modulus of the glass used in the glass cloth of this disclosure is preferably 60 GPa or higher. By using glass yarn with such a high modulus, the resulting glass cloth can be made to have a high modulus, making it easier to reduce warping of prepregs and printed circuit boards. From the viewpoint of achieving a high modulus, the bulk modulus is preferably 65 GPa or higher, more preferably 70 GPa or higher, even more preferably 72 GPa or higher, and even more preferably 73 GPa or higher. The upper limit of the bulk modulus that can be arbitrarily combined with these lower limits is not limited, but can be, for example, 100 GPa or less.

[0019] <Tensile strength of glass cloth> Preferably, one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer have a tensile strength of 15 N / 25 mm or more, as measured by the method described in the examples. Such glass cloth is less prone to breakage and fuzzing, and is easier to process to withstand transport. Preferably, one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer have a tensile strength of 20 N / 25 mm or more, more preferably 25 N / 25 mm or more, even more preferably 30 N / 25 mm or more, even more preferably 35 N / 25 mm or more, particularly preferably 40 N / 25 mm or more, and if processability is particularly important, 50 N / 25 mm or more, more preferably 70 N / 25 mm or more, and even more preferably 200 N / 25 mm or more. Furthermore, from the viewpoint of ease of handling, the tensile strength of one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer is preferably 500 N / 25 mm or less, more preferably 400 N / 25 mm or less, and especially when ease of handling is important, 150 N / 25 mm or less, and more preferably 70 N / 25 mm or less.

[0020] <Tensile strength of glass cloth per unit thickness> Preferably, one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer have a tensile strength per unit thickness of 1.1 N / 25 mm / μm or more, which is determined by dividing the tensile strength by the thickness. With such glass cloth, it is easy to apply the necessary tension during transport according to the thickness of the glass cloth, and it is easy to suppress fuzzing, wrinkles, and distortion of the weave. Preferably, one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer have a tensile strength per unit thickness of 1.3 N / 25 mm / μm or more, 1.5 N / 25 mm / μm or more, 1.7 N / 25 mm / μm or more, more preferably 1.9 N / 25 mm / μm or more, 2.0 N / 25 mm / μm or more, even more preferably 2.5 N / 25 mm / μm or more, 2.7 N / 25 mm / μm or more, and particularly preferably 3.0 N / 25 mm / μm or more. There are no specific restrictions, but it is acceptable if it is 8.0 N / 25 mm / μm or less, or 6.0 N / 25 mm / μm or less.

[0021] <Ratio of variation in tensile strength of glass cloth> The roll-shaped long glass cloth of this disclosure has a tensile strength variation ratio Sb / Sa of 0.6 or more. Here, "variation ratio" refers to the value obtained by Sb / Sa, where Sa is the larger of the tensile strengths in the warp direction of the surface layer and the inner layer of the roll-shaped long glass cloth, and Sb is the smaller of the two. As long as Sb / Sa is 0.6 or more, the tensile strength of the surface layer may be greater than or equal to the tensile strength of the inner layer, or the tensile strength of the inner layer may be greater than or equal to the tensile strength of the surface layer. In any case, the closer Sb / Sa is to 1.0, the smaller the difference in tensile strength in the longitudinal direction of the glass cloth, and the more effectively the occurrence of breakage, fuzzing, and distortion can be suppressed throughout the longitudinal direction of the glass cloth. The surface layer and inner layer of the roll-shaped long glass cloth refer to the following positions, respectively. Surface layer: Positions between 4% and 6% from the start of unwinding relative to the amount of glass cloth wound L (m). Inner layer: Position between 94% and 96% of the winding length L (m) of the glass cloth from the start of the winding.

[0022] Note that the above calculations for the positions of the surface and inner layers are rounded to the first decimal place. For example, for a roll of glass cloth with a winding length of 505m, the positions of the surface and inner layers from the starting point are as follows. Surface layer = 505m x 4% or more, 505m x 6% or less = 20m to 30m from the roll unwinding point. Inner layer = 505m x 94% or more, 505m x 95% or less = position between 475m and 485m from the roll out point.

[0023] From the viewpoint of easily obtaining the effects of this disclosure, the fluctuation ratio Sb / Sa is preferably 0.70 or higher, more preferably 0.72 or higher, even more preferably 0.74 or higher, even more preferably 0.76 or higher, and particularly preferably 0.78 or higher. Furthermore, the upper limit of the fluctuation ratio Sb / Sa may be 1.0 or less, or less than 1.0.

[0024] <Glass cloth> The glass cloth has a structure woven with glass yarns containing a plurality of glass filaments as warp and weft. The weaving structure of the glass cloth includes weaving structures such as plain weave, square weave, satin weave, twill weave, etc. Among them, the plain weave structure is preferred.

[0025] The driving density of the warp and weft constituting the glass cloth is preferably 10 - 120 threads / inch (= 10 - 120 threads / 25 mm), more preferably 40 - 100 threads / inch. If the driving density is within the above range, it is easy to obtain a glass cloth with a preferable thickness. The driving densities of the warp and weft may be different.

[0026] The basis weight (mass of the glass cloth) is preferably 8 - 250 g / m 2 、more preferably 8 - 130 g / m 2 、even more preferably 8 - 100 g / m 2 、still more preferably 8 - 80 g / m 2 、particularly preferably 8 - 50 g / m 2 、or 8 - 20 g / m 2 If the basis weight of the glass cloth is within the above range, it is easy to obtain a glass cloth with a preferable thickness.

[0027] The thickness of the glass cloth is preferably 120 μm or less, more preferably 100 μm or less. Particularly when emphasizing the miniaturization of electronic devices manufactured using the glass cloth, it is even more preferably 80 μm or less, 60 μm or less, still more preferably 50 μm or less, 40 μm or less, and particularly preferably 20 μm or less. The thickness of the glass cloth may be 5 μm or more, or 10 μm or more. Particularly when emphasizing the reduction of warping of electronic devices manufactured using the glass cloth, it is preferably 20 μm or more, even more preferably 50 μm or more, and particularly preferably 80 μm or more. If the thickness of the glass cloth is within the above range, it is easy to obtain a glass cloth suitable as an insulating material.

[0028] 〈Dielectric tangent of the glass cloth〉 Preferably, one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer have a dielectric loss tangent of 0.0080 or less at 10 GHz, as measured by the method described in the examples. More preferably, one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer have a dielectric loss tangent of 0.0060 or less, even more preferably 0.0057 or less, even more preferably 0.0045 or less, particularly preferably 0.0042 or less, 0.0041 or less, or 0.0040 or less. Such glass cloths tend to possess dielectric properties suitable for use as insulating materials. Furthermore, glass cloths with a dielectric loss tangent within the above range are brittle and susceptible to damage from physical external forces, thus making it easier to obtain the fracture, fuzzing, and distortion suppression effects of this disclosure.

[0029] <Difference in the variation of dielectric loss tangent in the longitudinal direction of glass cloth> In the roll-shaped long glass cloth of this disclosure, it is preferable that the absolute value of the dielectric loss tangent difference between the surface layer and the inner layer at 10 GHz, |Dfa-Dfb|, is 0.00040 or less. In this disclosure, |Dfa-Dfb| is also referred to as the "difference in dielectric loss tangent variation". Dfa: Dielectric loss tangent of the surface layer of a rolled, long glass cloth at 10 GHz. Dfb: Dielectric loss tangent of the inner layer of a rolled, long glass cloth at 10 GHz. The positions of the surface and inner layers of the rolled glass cloth are as described above.

[0030] In batch-type heated de-oiling processes, differences in temperature, ambient gas circulation, and oxygen levels occur depending on the winding position within the glass cloth roll, leading to variations in the amount of binder removed. Since binder residue causes an increase in dielectric loss tangent, uniformly controlling the amount of binder removed allows for the production of glass cloth rolls with a small dielectric loss tangent difference in the longitudinal direction. Furthermore, it is possible to obtain long rolls of glass cloth with dielectric properties suitable for use as an insulating material over long lengths.

[0031] The rolled long glass cloth of this disclosure is not limited to a specific manufacturing method, but in order to control the dielectric loss tangent difference in the longitudinal direction to a predetermined range, it is preferable to use a winding core with a large outer diameter in the heating and de-oiling process. From the viewpoint that the smaller the variation ratio of the tensile strength in the longitudinal direction of the glass cloth, the smaller the variation difference in dielectric loss tangent, and the easier it is to obtain the effects of this disclosure, the variation difference in dielectric loss tangent is more preferably 0.00020 or less, even more preferably 0.00015 or less, even more preferably 0.00010 or less, and particularly preferably 0.00005 or less.

[0032] <Glass type> The type of glass in the glass cloth of this disclosure is not particularly limited, but from the viewpoint of reducing the thermal expansion of the glass cloth, it may be S glass, T glass, silica glass, quartz glass, etc., or it may be glass with the following compositions.

[0033] In one embodiment, it is preferable to use a glass species having an SiO2 content of preferably 50% to 60% by mass, more preferably 52% to 56% by mass; a B2O3 content of preferably 10% to 20% by mass, more preferably 14% to 18% by mass; an Al2O3 content of preferably 13% to 23% by mass, more preferably 15% to 20% by mass; a CaO content of preferably 0% to 5% by mass, more preferably 1% to 3% by mass; and a MgO content of preferably 0% to 5% by mass, more preferably 1% to 3% by mass. Using such a glass species makes it particularly easy to suppress breakage, fuzzing, streaking, and distortion.

[0034] In another form, it is preferable to use a glass species having an SiO2 content of preferably 55% to 65% by mass, more preferably 58% to 63% by mass; a B2O3 content of preferably 3% to 10% by mass, more preferably 5% to 8% by mass; an Al2O3 content of preferably 17% to 25% by mass, more preferably 19% to 23% by mass; a CaO content of preferably 0% to 2% by mass, more preferably 0.01% to 0.40% by mass; and a MgO content of preferably 6% to 14% by mass, more preferably 8% to 12% by mass. Using such a glass species makes it easier to suppress breakage, fuzzing, streaks, and distortion.

[0035] Furthermore, in another form, it is preferable to use a glass species having an SiO2 content of preferably 45% to 55% by mass, more preferably 48% to 53% by mass; a B2O3 content of preferably 0% to 8% by mass, more preferably 2% to 6% by mass; an Al2O3 content of preferably 20% to 30% by mass, more preferably 22% to 27% by mass; a CaO content of preferably 0% to 2% by mass, more preferably 0.01% to 0.40% by mass; and a MgO content of preferably 0% to 10% by mass, more preferably 1% to 5% by mass. Using such a glass species makes it easier to suppress breakage, fuzzing, streaks, and distortion.

[0036] The elemental content of glass can be measured by atomic absorption spectrophotometry, inductively coupled plasma (ICP) emission spectroscopy, and other methods. For example, using a sample with known concentration, it is possible to measure the elemental content of each glass from a calibration curve created using instruments such as ICP-AES and ICP-MS.

[0037] <Glass thread> The average filament diameter of the glass filaments constituting the glass yarn is preferably 2.5 μm to 10.0 μm, more preferably 2.5 μm to 9.0 μm, even more preferably 3.5 μm to 8.0 μm, even more preferably 3.5 μm to 7.5 μm, and particularly preferably 3.5 μm to 7.0 μm. If the filament diameter is above the lower limit, it is easier to ensure the breaking strength of the filaments, and therefore less likely to occur in the resulting glass cloth. Also, if the filament diameter is below the upper limit, it is possible to prevent the mass of the glass cloth from becoming too large, making it easier to transport or process.

[0038] <Silane coupling agent> Preferably, the glass cloth has a surface treatment agent containing a silane coupling agent on its surface. More specifically, the glass threads (including glass filaments) constituting the glass cloth are preferably surface-treated with a surface treatment agent containing a silane coupling agent. The presence of a surface treatment agent in the glass cloth tends to improve its reactivity with the matrix resin.

[0039] Examples of silane coupling agents include the following formula (1): X(R) 3-n SiY n ...(1) {In formula (1), X is an organic functional group having at least one of a radically reactive unsaturated double bond group, such as a radically reactive carbon-carbon double bond, and an amino group; Y is independently an alkoxy group; n is an integer between 1 and 3; and R is a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group.} It is preferable to use the silane coupling agent indicated by [the specified symbol].

[0040] In formula (1), X is more preferably an organic functional group having one or more methacryloxy or acryloxy groups, from the viewpoint of reactivity with the matrix resin.

[0041] Regarding Y in formula (1) above, an alkoxy group having 1 to 5 carbon atoms (1, 2, 3, 4, or 5 carbon atoms) is preferred for stable treatment of the glass cloth.

[0042] As a surface treatment agent, the silane coupling agent shown in formula (1) may be used alone, or it may be used in mixture with two or more silane coupling agents in which X in formula (1) is different. Furthermore, the silane coupling agent shown in formula (1) can be used as a single agent or mixture thereof, for example, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 5-hexenyltrimethoxysilane, etc.

[0043] The molecular weight of the silane coupling agent is preferably 100 to 600, more preferably 150 to 500, and even more preferably 200 to 450. In particular, it is especially preferable to use two or more silane coupling agents with different molecular weights. By treating the glass filament surface with two or more silane coupling agents with different molecular weights, the density of the treatment agent on the glass surface increases, and the reactivity with the matrix resin tends to improve further.

[0044] <Carbon content> The carbon content of the glass cloth is preferably 0.01% by mass or more and 1.0% by mass or less, more preferably 0.02% by mass or more and less than 0.5% by mass, even more preferably 0.03% by mass or more and less than 0.4% by mass, even more preferably 0.03% by mass or more and less than 0.3% by mass, and particularly preferably 0.03% by mass or more and less than 0.2% by mass. When the carbon content is above the lower limit, the silane coupling agent can sufficiently cover the surface, making it easier to improve the heat resistance and reliability of the printed circuit board. Also, when the carbon content is below the upper limit, it is possible to prevent the adhesion of binder residue and excess silane coupling agent, making it easier to obtain glass cloth that exhibits a low dielectric loss tangent, and making it easier to improve the heat resistance of the printed circuit board. The carbon content is measured by the method described in the examples. The carbon content of the glass cloth can be controlled in the heating de-oiling process and the surface treatment process.

[0045] <Difference in carbon content in the longitudinal direction of glass cloth> In the roll-shaped long glass cloth of this disclosure, it is preferable that the absolute value of the difference in carbon content between the surface layer and the inner layer, |Ca-Cb|, is 0.028% by mass or less. In this disclosure, |Ca-Cb| is also referred to as the "difference in carbon content variation". Ca: Carbon content in the surface layer of rolled, long glass cloth Cb: Carbon content in the inner layer of rolled, long glass cloth. The positions of the surface and inner layers of the rolled glass cloth are as described above.

[0046] In batch-type heat de-oiling processes, differences in temperature, ambient gas circulation, and oxygen levels occur depending on the winding position within the glass cloth roll, leading to variations in binder removal. Binder residue increases dielectric loss tangent and deteriorates heat resistance; therefore, uniformly controlling the amount of binder removed allows for the production of glass cloth rolls with small dielectric loss tangent differences in the longitudinal direction. Furthermore, since binder residue reduces heat resistance, uniformly controlling the amount of binder removed allows for the production of glass cloth rolls with small variations in heat resistance in the longitudinal direction.

[0047] The rolled long glass cloth of this disclosure is not limited to a specific manufacturing method, but in order to control the difference in carbon content in the longitudinal direction to a predetermined range, it is preferable to use a winding core with a large outer diameter in the heating de-oiling process and to control the heating time. From the viewpoint that the smaller the variation ratio of the tensile strength in the longitudinal direction of the glass cloth, the smaller the variation difference in carbon content, and the easier it is to obtain the effects of this disclosure, the variation difference in carbon content is more preferably 0.023% by mass or less, even more preferably 0.018% by mass or less, even more preferably 0.015% by mass or less, and particularly preferably 0.012% by mass or less.

[0048] <brightness> The brightness of glass cloth varies depending on the type of glass, the condition of the glass surface, and any adhering substances. The brightness (L) measured by the SCE method is used for one or both of the glass cloth located in the inner layer and / or the glass cloth located in the outer layer of a roll of long glass cloth. * The value is preferably 88 or higher, more preferably 90 or higher, even more preferably 92 or higher, and even more preferably 93 or higher. * There is no particular upper limit to the value, but for example, it is around 99 or less, or 98 or less. If the binder is not sufficiently removed in the heat de-oiling process in glass cloth and a large amount of binder and its carbides remain, the brightness tends to be low. If the brightness of the glass cloth is above the lower limit value mentioned above, the binder is sufficiently and appropriately removed in the heat de-oiling process, and the heat resistance of the substrate using such glass cloth tends to improve. These effects are particularly noticeable in glass cloth where the bulk CTE of the glass is in the range of 1.0 ppm / K to 3.0 ppm / K. The brightness of the glass cloth can be controlled by selecting the type of glass, the temperature and time of the heat de-oiling process, and the surface treatment process.

[0049] <Difference in brightness variation along the longitudinal direction of glass cloth> The rolled long glass cloth of this disclosure has an absolute value |L| for the difference in brightness between the surface layer and the inner layer. * aL * b| is preferably 1.5 or less. In this disclosure, |L| * aL* b| is also called the "difference in brightness variation". L * a: Brightness of the surface layer of rolled, long glass cloth L * b: Brightness in the inner layer of rolled, long glass cloth The positions of the surface and inner layers of the rolled long glass cloth are as described above. The absolute value of the brightness difference is more preferably 1.3 or less, even more preferably 1.0 or less, even more preferably 0.8 or less, and particularly preferably 0.6 or less.

[0050] In the heating and de-oiling process, differences in temperature, ambient gas circulation, and oxygen content can occur depending on the winding position within the glass cloth roll, leading to variations in brightness. By uniformly controlling the brightness, it is possible to obtain long rolls of glass cloth with dielectric properties and heat resistance suitable for use as an insulating material.

[0051] <Winding amount of long rolls of glass cloth> The amount of glass cloth wound in a roll, i.e., the length of the glass cloth in the longitudinal direction between the starting and ending points of the winding, is preferably 500m or more. In such glass cloth, the occurrence of breakage, fuzzing, and distortion due to winding tightening during the heat de-oiling process of the glass cloth is significantly observed, making it easier to obtain a suppression effect. The amount of glass cloth wound in a roll is preferably 700m or more, more preferably 900m or more, and even more preferably 1000m or more. The larger the amount wound, the more significantly the occurrence of breakage, fuzzing, and distortion due to winding tightening of the inner layer during the heat de-oiling process of the glass cloth is observed, making it easier to obtain a suppression effect. The upper limit of the amount wound is not particularly limited, but is preferably 5000m or less, more preferably 4000m or less, even more preferably 3000m or less, and particularly preferably 2500m or less. When the winding amount is below the above upper limit, it is easier to handle, and it is also easier to suppress breakage, fuzzing, streaks, and distortion of the fiberglass cloth due to tightening of the inner layer during the heat de-oiling process.

[0052] In addition, in the case of glass cloth rolls, the ends of multiple glass cloths may be joined together with tape or the like to form a single roll of glass cloth. The roll of glass cloth of this disclosure may include such joined sections, but in this case, the amount of glass cloth wound shall be handled independently for each of the joined long glass cloths. That is, for example, if a 500m glass cloth 1, a 700m glass cloth 2, and an 800m glass cloth 3 are joined together to form a single roll of glass cloth totaling 2000m, this roll of glass cloth has joined sections 1 and 2 at 500m and 1200m from the surface, respectively. In this case, the amount of glass cloth wound in the roll of glass cloth shall be considered independently for glass cloths 1 to 3 as follows. Glass cloth 1: 500m from the start of the winding to the joint 1 Glass cloth 2: 700m from joint 1 to joint 2 Glass cloth 3: 800m from the joint 2 to the end of the winding Then, the tensile strength and dielectric loss tangent are measured in the surface and inner layers of glass cloths 1 to 3, respectively. Here, it is preferable that all of glass cloths 1 to 3 are long pieces of glass cloth, however, it is sufficient if any one of them is long. Furthermore, it is preferable that all of glass cloths 1 to 3 possess the characteristic features of this disclosure, such as tensile strength and dielectric loss tangent, however, it is sufficient if any one of them possesses the characteristic features of this disclosure.

[0053] <Crooked eyes> The amount of distortion of the glass cloth is preferably 30 mm or less. In the heat de-oiling process of the glass cloth, the inner layer of the roll experiences stronger winding tightness during cooling shrinkage compared to the outer circumference of the roll, reducing circumferential stress and making it prone to winding wrinkles. Low thermal expansion glass cloth is susceptible to thermal expansion damage to the winding core during the heat de-oiling process, and because the glass is hard, the resulting winding wrinkles are difficult to eliminate, leading to distortion. If the distortion is below the above upper limit, there is less deviation in the direction of the cloth fibers, making it easier to obtain a substrate with reduced warping. The amount of distortion is preferably 25 mm or less, more preferably 20 mm or less, even more preferably 15 mm or less, even more preferably 10 mm or less, and particularly preferably 5 mm or less. The amount of distortion may be 0 mm or more.

[0054] The rolled long glass cloth of this disclosure is not limited to a specific manufacturing method, but in order to control the amount of curvature of the glass cloth to a predetermined range, it is preferable to use a winding core with a large outer diameter in the heat de-oiling process and to control the cooling rate after the completion of the heat de-oiling process.

[0055] <Core tube> The core tube that forms the axis of the roll-shaped long glass cloth of this disclosure can be made of paper, resin, fiber-reinforced plastic (FRP), or metal. Paper, resin, or FRP are preferred from the viewpoint of preventing the incorporation of metal foreign matter into the glass cloth. On the other hand, among the core tubes, the winding core used in particular during the heating and de-oiling process is preferably made of metal from the viewpoint of heat resistance.

[0056] The outer diameter of the core tube is preferably Φ100mm to Φ400mm, more preferably Φ120mm to Φ350mm, even more preferably Φ150mm to Φ300mm, and particularly preferably Φ150mm to Φ250mm. If the outer diameter of the core tube excluding the winding core is above the lower limit, it is easier to prevent damage to the wound glass cloth. Also, if the outer diameter of the core tube excluding the winding core is below the upper limit, it is easier to reduce the volume of the glass cloth roll.

[0057] <Application> The rolled glass cloth of this disclosure exhibits minimal breakage and fuzzing over long lengths, and preferably has low thermal expansion properties, making it suitable for use, for example, in printed circuit boards.

[0058] Method for manufacturing roll-shaped, long glass cloth The present disclosure's method for manufacturing a roll of glass cloth includes the step of weaving glass yarn containing a plurality of glass filaments as warp and weft threads to obtain glass cloth. The method for manufacturing glass cloth may further include the steps of heat-cleaning the glass yarn or glass cloth and treating the glass yarn or glass cloth with a surface treatment agent. The method for manufacturing glass cloth may optionally further include the step of opening the glass cloth fibers.

[0059] <Weaving process> The weaving method is not particularly limited as long as the weft and warp threads can be woven to achieve a predetermined weave structure. The preferred composition and structure of the glass yarn used, as well as the weave structure, are as described above.

[0060] <Heat deoiling process> The heat de-oiling process can be performed on glass yarn, or on woven glass cloth. In other words, the process of weaving glass yarn to obtain glass cloth may be performed before, during, or after the heat de-oiling process. From the viewpoint of suppressing a decrease in the strength of the glass cloth and suppressing the generation of binder residue, it is preferable to use a method of heat de-oiling the glass yarn or glass cloth (hereinafter simply referred to as "glass" in this process) at a relatively low temperature (e.g., less than 600°C) for a long period of time (e.g., 24 hours or more).

[0061] The temperature for heat degreasing is preferably 100°C to 500°C, more preferably 250°C to 450°C, and even more preferably 350°C to 450°C. The heating time for heat degreasing can be appropriately selected, for example, preferably 24 hours to 300 hours, more preferably 48 hours to 200 hours, and even more preferably 72 hours to 150 hours. If the heat degreasing temperature and time are within the above ranges, the adhesive adhering to the glass can be easily removed sufficiently.

[0062] In thermal degreasing, known heating methods, heating media, heating mechanisms, heating devices, and heating components can be used as heating means, as long as they allow for suitable control of the thermal degreasing temperature. For example, (1) a method of heating glass in a heating furnace, (2) a method of applying high-temperature steam to glass, etc. Heating can be carried out sequentially or continuously in a closed system, or a combination of a closed system and an open system.

[0063] In the case of a closed system, from the viewpoint of suitable heating by heating means, it is preferable to place the glass inside the heating furnace, and in that case, from the viewpoint of storage space and heating range, it is preferable to heat the glass cloth while storing it in a roll.

[0064] From the viewpoint of heating efficiency, the heating furnace is preferably equipped with means for discharging the gas generated in the heating furnace and / or means for air circulation. The gas discharge means may be a nozzle, gas pipe, small hole, gas vent valve, etc. The air circulation means may be a fan, air conditioning equipment, etc.

[0065] A batch-type heating furnace is preferred, capable of housing glass (e.g., rolls of glass cloth) and heating it at a predetermined ambient temperature.

[0066] The heat de-oiling process is preferably performed on roll-shaped glass cloth that has been woven and wound onto a core. In this case, it is preferable to use a core made from a material with a thermal expansion coefficient of 14 ppm / K or less at 0 to 100°C during the heat de-oiling process. Here, the core refers to the core tube that winds the glass cloth, and is particularly used during the heat de-oiling process. The thermal expansion coefficient of the core (0 to 100°C) is preferably 12 ppm / K or less, more preferably 8 ppm / K or less, even more preferably 5 ppm / K or less, and particularly preferably 3 ppm / K or less. Using such a core allows for high tensile strength of the glass cloth and easy adjustment of the fluctuation ratio Sb / Sa. Examples of core materials include aluminum-plated steel sheet, iron, SUS403, SUS430, Invar, Super Invar, alumina, and quartz. From the viewpoint of durability, weight, and handling, metal cores such as aluminum-plated steel sheet, iron, SUS403, SUS430, Invar, and Super Invar are preferred.

[0067] According to the modified Hakiel theory, it is generally known that the circumferential and radial stresses of a rolled glass cloth differ along its longitudinal direction. The inventors have revealed that, due to the differing stresses applied to the glass cloth, the damage to the glass cloth caused by the expansion and contraction of the core during heat de-oiling varies along the longitudinal direction. Furthermore, the inventors have found that in order to suppress breakage and fuzzing of the glass cloth, it is effective to make the stress applied to the glass cloth, especially the circumferential stress, as uniform as possible along the longitudinal direction. From this viewpoint, it is preferable that the diameter (outer diameter) of the winding portion of the core used during heat de-oiling is Φ500 mm or more. Preferably, the outer diameter of the winding portion of the core is Φ550 mm or more, more preferably Φ600 mm or more, and even more preferably Φ650 mm or more. Using such a core makes the circumferential stress applied to the glass cloth relatively uniform, increases the tensile strength of the glass cloth, and makes it easier to control the Sb / Sa ratio within a predetermined range. Furthermore, the variation in dielectric loss tangent |Dfa-Dfb|, the variation in carbon content, the variation in brightness, and the amount of grain curvature can be easily controlled within a predetermined range. Streaks can also be easily suppressed. The upper limit of the outer diameter of the winding portion of the core is not particularly limited, but from the viewpoint of handling, Φ1000mm or less and Φ800mm or less are preferred.

[0068] After the heating and de-oiling process is completed for a predetermined time, the glass cloth is returned to room temperature. The cooling rate after the completion of this heating and de-oiling process is preferably 70°C / h or less. Preferably, the cooling rate is 50°C / h or less, more preferably 40°C / h or less, and even more preferably 30°C / h or less. By controlling the cooling rate, the tensile strength of the glass cloth can be increased, and the Sb / Sa ratio can be easily controlled within a predetermined range. In addition, the amount of mesh curvature can also be easily controlled within a predetermined range.

[0069] <Surface treatment process> The surface treatment process can be performed on glass yarn, or on woven glass cloth. In other words, the process of weaving glass yarn to obtain glass cloth may be performed before, during, or after the surface treatment process. The surface treatment process may include, for example, a coating step of applying a silane coupling agent to the surface of the glass yarn or glass cloth (hereinafter simply referred to as "glass" in this process) with a treatment solution at a concentration of 0.1% to 0.5% by mass. The surface treatment process may further include a fixing step of fixing the silane coupling agent to the surface of the glass by heating and drying. This makes it easier to suitably surface treat the glass.

[0070] Methods for applying the treatment solution to the glass in the coating process include (a) immersing or passing the glass through the treatment solution stored in a bath (hereinafter referred to as the "immersion method"), and (b) applying the treatment solution to the glass using a roll coater, die coater, or gravure coater. When using the immersion method, it is preferable to select an immersion time of 0.5 seconds to 1 minute for the glass in the treatment solution. When using the immersion method, the glass can be passed through the treatment solution at a transport speed of 10 m / min to 50 m / min while applying a predetermined tension to the glass (for example, 100 N to 250 N). After applying the treatment solution to the glass, the solvent contained in the treatment solution can be heated and dried using methods such as hot air or electromagnetic waves. To facilitate uniform application of the surface treatment agent to the glass surface, it is preferable to immerse the glass cloth in the surface treatment solution and then squeeze it with a rubber roller under constant pressure.

[0071] The concentration of the surface treatment agent in the treatment solution is preferably 0.1% to 0.5% by mass, more preferably 0.1% to 0.45% by mass, and even more preferably 0.1% to 0.4% by mass, based on the total mass of the treatment solution. This makes it easier to surface treat the glass more effectively.

[0072] In the fixing process, the heating and drying temperature is preferably 80°C or higher, and more preferably 90°C or higher, so that the reaction between the silane coupling agent and the glass can proceed sufficiently. Furthermore, the heating and drying temperature is preferably 300°C or lower, and more preferably 180°C or lower, in order to prevent deterioration of the organic functional groups of the silane coupling agent.

[0073] <Opening process> The method for manufacturing glass cloth may further include a step of opening the glass cloth fibers. For example, the fiber-opening method in the glass cloth process may involve using spray water (high-pressure water opening), a vibro-washer, ultrasonic water, or a mangle. The composition of the glass cloth usually does not change before and after opening.

[0074] The above steps do not necessarily have to be carried out in a manner that can be distinguished as separate steps; multiple steps can be carried out together (simultaneously). Furthermore, the method for manufacturing glass cloth can include any steps other than those described above. For example, a slitting step can be included after the fiber opening step. Also, if possible, the order of the above steps can be changed.

[0075] Prepreg The prepreg of this disclosure contains the roll-shaped long glass cloth and a matrix resin impregnated in the glass cloth. This makes it possible to provide a roll-shaped long prepreg with less variation in properties in high yield.

[0076] As the matrix resin, a thermosetting resin or a thermoplastic resin can be used. If possible, both may be used in combination, or other resins may be further included.

[0077] Examples of thermosetting resins include (a) to (e) below. (a) An epoxy resin obtained by reacting and curing a compound having an epoxy group with a compound having at least one group selected from the group consisting of an amino group, a phenol group, an acid anhydride group, a hydrazide group, an isocyanate group, a cyanate group, and a hydroxyl group that reacts with the epoxy group. (b) A radical polymerization type curing resin obtained by curing a compound having at least one group selected from the group consisting of an allyl group, a methacrylic group, and an acrylic group. (c) A maleimidotriazine resin obtained by reacting and curing a compound having a cyanate group with a compound having a maleimide group. (d) A thermosetting polyimide resin obtained by reacting a maleimide compound with an amine compound and curing the reaction. (e) A benzoxazine resin obtained by crosslinking and curing a compound having a benzoxazine ring by thermal polymerization. Furthermore, (a) when obtaining epoxy resin, the compounds can be reacted without a catalyst, or the compounds can be reacted by adding a catalyst with catalytic activity such as imidazole compounds, tertiary amine compounds, urea compounds, and phosphorus compounds. Also, (b) when obtaining radical polymerization-type curing resin, a thermal decomposition catalyst or a photodecomposition catalyst can be used as a reaction initiator.

[0078] Examples of thermoplastic resins include polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, aromatic polyamide, polyetheretherketone, thermoplastic polyimide, insoluble polyimide, polyamideimide, and fluororesin. For insulating materials of printed circuit boards for high-speed communication, polyphenylene ether or modified polyphenylene ether with high radical reactivity is preferred.

[0079] When the matrix resin used in printed circuit boards for high-speed communication has vinyl groups or methacrylic groups, silane coupling agents that are relatively hydrophobic and have functional groups that participate in radical reactions, such as methacrylic groups, are compatible with the matrix resin.

[0080] As described above, thermosetting resins and thermoplastic resins can be used in combination. Furthermore, the prepreg may further contain inorganic fillers. Inorganic fillers are preferably used in combination with thermosetting resins, and examples include aluminum hydroxide, zirconium oxide, calcium carbonate, alumina, mica, aluminum carbonate, magnesium silicate, aluminum silicate, silica, talc, glass short fibers, aluminum borate, and silicon carbide. Inorganic fillers may be used alone or in combination of two or more types. [Examples]

[0081] Measurement and Evaluation Methods <Method for measuring thickness> The thickness T of the glass cloth was determined in accordance with JIS R 3420, section 7.10. Specifically, a micrometer was used, and the spindle was rotated gently while lightly contacting the sample's surface parallel to the measurement surface. The scale reading was then taken after the ratchet clicked three times. Note that JIS R 3420, section 7.10, specifies general test methods for cloth products such as glass cloth.

[0082] <Method for measuring fabric weight> The basis weight of the glass cloth was determined by cutting the glass cloth to a predetermined size and dividing its weight by the sample area. In this example or comparative example, the glass cloth was 10 cm 2 The process of cutting the glass cloth to the specified size and measuring its weight was repeated 10 times, and the average value was used as the basis weight for each piece of glass cloth.

[0083] <Method for measuring converted thickness> Glass cloth is a discontinuous planar material with air between the glass fibers. Therefore, the equivalent thickness was calculated by dividing the basis weight (mass of the cloth) of each glass cloth by the density of the glass itself. Specifically, the following formula: Equivalent thickness (μm) = Basis weight (g / m²) 2 ) ÷ density of glass (g / cm³) 3 ) The converted thickness was calculated using this method. This converted thickness value was used for measurement using the resonance method.

[0084] <Method for measuring the winding amount of rolled glass cloth> The length L (m) of the roll of glass cloth, that is, the longitudinal length between the starting and ending points of the winding, was determined by setting the roll of glass cloth in a winding machine, winding it, and measuring the distance L between the starting and ending points using a length measuring device attached to the winding machine.

[0085] <Method for measuring dielectric loss tangent and method for calculating |Dfa-Dfb|> The dielectric loss tangent of each glass cloth was determined in accordance with IEC 62562. Specifically, glass cloth samples, sampled to the size required for measurement in a split-cylinder resonator, were stored in a constant temperature and humidity oven at 23°C and 50%RH for at least 8 hours. After storage, the dielectric properties at 10 GHz were measured on the samples using a split-cylinder resonator (EM Labs) and an impedance analyzer (Agilent Technologies). Measurements were performed five times for each sample, and the average value was calculated. The above-mentioned converted thickness was used as the thickness of each sample. Note that IEC 62562 mainly specifies a method for measuring the dielectric properties in the microwave band of fine ceramic materials used in microwave circuits. Measurements were performed five times each on the surface and inner layers of the roll-shaped glass cloth obtained in the example, and the average values ​​were taken as the dielectric loss tangent of the surface layer (Dfa) and the dielectric loss tangent of the inner layer (Dfb). Furthermore, |Dfa-Dfb| was calculated using Dfa and Dfb obtained by the above method. Surface layer: Positions between 4% and 6% from the start of unwinding relative to the amount of glass cloth wound L (m). Inner layer: Position between 94% and 96% of the winding length L (m) of the glass cloth from the start of the winding.

[0086] <Method for measuring bulk CTE> Bulk glass with the same composition as each glass cloth was prepared, and its thermal expansion coefficient (bulk CTE: ppm / K) was measured by TMA (Thermo-mechanical analysis) according to JIS R 3102. A TMA instrument (TMA6000 manufactured by SII Nanotechnology Co., Ltd.) was used for the measurements, and the temperature range was 50 to 150°C. Measurement mode: Compression Test start temperature: 30℃ Heating rate: 3°C / min Maximum test temperature: 250℃ Maximum temperature holding time: 5 minutes

[0087] <Method for measuring bulk modulus> Bulk glass with the same composition as each glass cloth was prepared, and the bulk modulus (GPa) was measured using the ultrasonic pulse method in accordance with JIS R 1602:1995.

[0088] <Method for measuring the carbon content of glass cloth and method for calculating |Ca-Cb|> The surface-treated glass cloths for the outer and inner layers were heated at approximately 800°C for 1 minute, and the amount of carbon dioxide in the generated gas was measured by gas chromatography to determine the amount of carbon dioxide in the generated gas. The total carbon content of the surface-treated glass cloth was determined by comparing it with the amount of carbon dioxide generated when a predetermined amount of acetanilide (C8H9NO) was similarly heated at approximately 800°C for 1 minute. A SUMIGRAPH NC-90A (manufactured by Sumika Analysis Center) was used for the measurements. Molecular weight of acetanilide = 135.17 Carbon content of acetanilide = 71.09%

[0089] In other words, the total carbon content of the glass cloth was calculated based on the following formula. Total carbon content of glass cloth = [{mass of acetanilide × (carbon content of acetanilide / 100)} / peak area due to carbon dioxide generated from acetanilide] × {(peak area of ​​carbon dioxide generated from glass cloth / mass of glass cloth) × 100}

[0090] Measurements were taken five times each on the surface and inner layers of the roll-shaped long glass cloth obtained in the examples, and the average values ​​were taken as the carbon content of the surface layer (Ca) and the carbon content of the inner layer (Cb). Furthermore, |Ca-Cb| was calculated using the Ca and Cb obtained by the above method. Surface layer: Positions between 4% and 6% from the start of unwinding relative to the amount of glass cloth wound L (m). Inner layer: Position between 94% and 96% of the winding length L (m) of the glass cloth from the start of the winding.

[0091] <Method for measuring tensile strength and calculating Sb / Sa> In accordance with JIS R3420, five tensile tests were performed on the warp direction of the glass cloth, and the average value was taken as the tensile strength of the glass cloth. Specifically, five measurements were taken each on the surface and inner layers of the roll-shaped long glass cloth obtained in the example, and the average values ​​were calculated. The value with the higher tensile strength was designated as Sa, and the value with the lower tensile strength was designated as Sb. Furthermore, Sb / Sa was calculated using Sa and Sb obtained by the above method. Surface layer: Positions between 4% and 6% from the start of unwinding relative to the amount of glass cloth wound L (m). Inner layer: Position between 94% and 96% of the winding length L (m) of the glass cloth from the start of the winding.

[0092] <Method for calculating strength per unit thickness> Using the thickness T of the glass cloth and the tensile strength of the glass cloth, the following equation (A): Tensile strength in the warp direction of glass cloth (N / 25mm) / Thickness T of glass cloth (μm) ... (A) From this, the tensile strength per unit thickness of the glass cloth was determined.

[0093] <Method for measuring the brightness of glass cloth and |L * aL * Method for calculating b| Samples of surface-treated glass cloth were taken from near the center in the width direction, at the positions of the surface layer and the inner layer. 96 sheets each of the surface layer and inner layer glass cloth were stacked, and a whiteness meter (Konica Minolta Japan, model: CM-2600d) was used to measure the brightness and L of the surface and inner layers using the SCE method. * The values ​​were measured. Each measurement was taken 5 times, and the average value was used to determine the surface brightness (L). * a) and the brightness of the inner layer (L * b) was used. Also, L was obtained using the above method. * Using a and Cb, |L * aL * b| was calculated. Surface layer: Positions between 4% and 6% from the start of unwinding relative to the amount of glass cloth wound L (m). Inner layer: Position between 94% and 96% of the winding length L (m) of the glass cloth from the start of the winding.

[0094] <Method for measuring the amount of curvature> The amount of stitch curvature was determined by measuring the maximum amount of weft slippage in the warp direction using a ruler, according to the method described in JIS L1096. Specifically, the distance of a single weft thread from a reference line perpendicular to the warp direction of the glass cloth was measured over the entire width, and the amount of stitch curvature was determined by subtracting the minimum value from the maximum value. Measurements were taken on both the surface and inner layers of the roll-shaped long glass cloth obtained in the example, and the larger value was recorded.

[0095] <Method for evaluating fluffiness> The glass cloth is placed on a roll-to-roll inspection table, under a tension of 100N / 1000mm, and visually inspected for 1 meter while being illuminated with a halogen lamp. 2 The number of protrusions of 0.8 mm or more per unit area was determined, and the fluffiness was evaluated according to the following criteria. The surface and inner layers of the roll-shaped long glass cloth obtained in the examples were evaluated separately. A: Number of downy fibers: 5 or less B: Number of fuzzy fibers: 6 to 10 C: Number of feathers: 11 to 15 D: Number of feathers: 16 to 20 E: Number of feathers: 21 or more, or 25 or less F: Number of feathers: 26 to 30 G: Number of feathers: 31 to 40 H: Number of feathers: 41 to 50 I: Number of feathers: 51 to 60 J: Number of feathers: 61 to 70 K: Number of feathers 71 or more

[0096] <Inspection method for the appearance (streaks) of glass cloth> The glass cloth was visually inspected every meter on a roll-to-roll inspection table under a tension of 100N / 1300mm and illuminated with a halogen lamp, to check for streaks (flat wrinkles) on the glass cloth. The quantity of defective products was counted as follows: products with one or more streaks per meter were counted as defective, and products with no streaks were counted as good products. Based on the inspection results, the glass cloths of the example and comparative example were graded according to the following indicators. A: The total number of defective items with streaks is less than 10% of the total amount of fiberglass cloth wound. B: The total number of defective items with streaks is between 10% and 20% of the total amount of glass cloth wound. C: The total number of defective items with streaks exceeds 20% of the total amount of glass cloth wound.

[0097] <Method for evaluating processability> In the winding section of the surface treatment process in each embodiment, the glass cloth was visually inspected along its entire length, and the presence or absence of tears of 1 cm or larger in the warp and / or weft threads of the glass cloth was evaluated.

[0098] <Method for manufacturing laminated boards> • Example 2 A varnish was prepared by adding 45 parts by mass of polyphenylene ether (SABIC, Noryl SA9000), 10 parts by mass of triallyl isocyanurate, 45 parts by mass of toluene, and 0.6 parts by mass of 1,3-di(tert-butylisopropylbenzene) to a stainless steel container and stirring at room temperature for 1 hour. The prepared varnish was immersed in the roll-shaped glass cloth obtained in Example 2 while being transported at a speed of 1 m / min, and excess varnish was scraped off through a slit with an adjusted gap so that the resin content was 65% by mass. The glass cloth was then dried at a drying temperature of 130°C for 2 minutes and 30 seconds to obtain a prepreg. From the obtained prepreg, 6 sheets each of prepreg obtained from the surface and inner layers of the roll-shaped glass cloth were stacked, for a total of 12 sheets, and 12 μm thick copper foil was placed on top and bottom, and dried at 200°C and 40 kg / cm². 2 By heating and pressurizing for 120 minutes, a laminated board with a thickness of 1.2 mm was obtained.

[0099] Examples 1, 3-16, and Comparative Examples 1-8 A varnish was prepared by adding 80 parts by mass of low-brominated bisphenol A epoxy resin, 20 parts by mass of cresol novolac epoxy resin, 2 parts by mass of dicyandiamide, 0.2 parts by mass of 2-ethyl-4-methylimidazole, and 100 parts by mass of 2-methoxyethanol to a stainless steel container and stirring at room temperature for 1 hour. The prepared varnish was immersed in the roll-shaped long glass cloth obtained in Examples 1, 3-16, and Comparative Examples 1-8 while being transported at a speed of 3 m / min, and the excess varnish was scraped off through a slit with an adjusted gap so that the resin content was 65% by mass. The glass cloth was then dried at a drying temperature of 160°C for 1 minute and 30 seconds to obtain a prepreg. From the obtained prepreg, 6 sheets each of prepreg obtained from the surface and inner layers of the roll-shaped long glass cloth were stacked, for a total of 12 sheets, and then 12 μm thick copper foil was placed on top and bottom, and dried at 200°C and 40 kg / cm². 2 By heating and pressurizing for 120 minutes, a laminated board with a thickness of 1.2 mm was obtained.

[0100] <Method for evaluating curvature> The steel foil was removed from the laminate obtained by the above method of lamination by etching, and a test piece for measuring warpage was formed, which was a flat plate with dimensions of 80 mm (length) x 60 mm (width) x 1 mm (thickness). This test piece was heated at 150°C for 30 minutes. After that, when one corner of the test piece was placed in contact with a flat surface, the distance generated between the corner diagonally opposite the corner in contact with the flat surface and the flat surface was measured with calipers. For each of the four corners of the above warpage measuring test piece placed in contact with a flat surface, the above distance was measured and evaluated as follows: "I" for warpage of 1 mm or less, "II" for warpage of more than 1 mm and 3 mm or less, "III" for warpage of more than 3 mm and 6 mm or less, "IV" for warpage of more than 6 mm and 10 mm or less, "V" for warpage of more than 10 mm and 15 mm or less, and "VI" for warpage of more than 15 mm.

[0101] <Method for evaluating heat resistance> After removing the copper foil from the laminate obtained by the above method of lamination, it was heated and water-absorbed in a pressure cooker container at 133°C for 70 hours. Furthermore, the water-absorbed laminate was immersed in a 288°C solder bath for 20 seconds, and a 0.03 cm layer was removed due to delamination at the interface between the glass cloth and the resin. 2 The presence or absence of the above-mentioned blistering was visually confirmed. Six tests were conducted on each glass cloth. The evaluation of heat resistance is as follows. Note that the less blistering the glass cloth tends to be, the better its heat resistance. A: Of the six laminated boards, none showed any bulging. B: There was a bulge in one of the laminated boards. C: There was bulging in 2-3 layers of laminated board. D: There was bulging in 4 to 6 layers of laminated board.

[0102] Glass composition and bulk CTE Table 1 shows the glass compositions A to C used in the examples and comparative examples. [Table 1]

[0103] Manufacturing of glass cloth <Manufacturing of the 1017 series Seiki Cross> Using glass yarn, a cloth was woven in an air-jet loom with a weave density of 95 warp threads / 25mm and 95 weft threads / 25mm. The cloth width was 1300mm. For the warp threads, glass yarn with an average filament diameter of 4.0μm, 50 filaments, and 1.0Z twist was used. Similarly, for the weft threads, glass yarn with an average filament diameter of 4.0μm, 50 filaments, and 1.0Z twist was used.

[0104] <Manufacturing of the 1035 series Seiki Cross> Using glass yarn, a cloth was woven in an air-jet loom with a weave density of 66 warp threads / 25mm and 68 weft threads / 25mm. The cloth width was 1300mm. For the warp threads, glass yarn with an average filament diameter of 5.0μm, 100 filaments, and 1.0Z twist was used. Similarly, for the weft threads, glass yarn with an average filament diameter of 5.0μm, 100 filaments, and 1.0Z twist was used.

[0105] <Manufacturing of the 2116 series Seiki Cross> Using glass yarn and an air-jet loom, a cloth was woven with a weave density of 60 warp threads / 25mm and 58 weft threads / 25mm. The cloth width was 1300mm. For the warp threads, silica glass yarn with an average filament diameter of 7.0μm, 200 filaments, and 1.0Z twist was used. Similarly, silica glass yarn with an average filament diameter of 7.0μm, 200 filaments, and 1.0Z twist was used for the weft threads.

[0106] Examples and Comparative Examples <Example 1> A 1017 series raw cloth was prepared using glass yarn of glass composition A, wound onto a Super Invar core with an outer diameter of Φ650 mm, and de-oiled by heating in a furnace at 400°C for 70 hours (heating de-oiling process). The glass cloth was then cooled at a rate of 45°C / hour to return to room temperature. Next, a treatment solution (surface treatment type: amino) was prepared by dispersing 0.30% by mass of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane; SZ6032 (manufactured by Toray Dow Corning) in pure water adjusted to pH=3 with acetic acid. The cloth was immersed in the treatment solution at a line tension of 250 N / m (surface treatment agent coating process), squeezed with an NBR rubber roll at a pressure of 0.3 MPa, and then heated and dried at 130°C for 60 seconds to fix the silane coupling agent (fixing process). The dried cloth was sprayed at a rate of 1.7 kg / cm². 2 After high-pressure fiber separation, the glass cloth was dried at 130°C for 1 minute (drying process) and then wound onto another core tube to obtain a roll of long glass cloth. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding length L, measured with a length measuring device attached to the unwinding machine, was 1000m.

[0107] <Example 2> A roll of long glass cloth was obtained in the same manner as in Example 1, except that the cooling rate in the heating and de-oiling process was changed to 30°C / hour, and the surface treatment was performed using a treatment solution (surface treatment type: methacrylic) in which 0.15% by mass of 3-methacryloxypropyltrimethoxysilane; Z6030 (manufactured by Dow-Toray) and 0.15% by mass of 5-hexenyltrimethoxysilane; Z6161 (manufactured by Dow-Toray) were dispersed. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L measured with a length measuring device attached to the unwinding machine was 1000m.

[0108] <Example 3> A roll of long glass cloth was obtained in the same manner as in Example 1, except that the material was wound onto an aluminum-plated steel core during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 30°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000m.

[0109] <Example 4> A roll of long glass cloth was obtained in the same manner as in Example 1, except that the material was wound onto a core with an outer diameter of Φ550 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 30°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0110] <Example 5> A roll of long glass cloth was obtained in the same manner as in Example 3, except that the material was wound onto a core with an outer diameter of Φ550 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 45°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0111] <Example 6> A roll of long glass cloth was obtained in the same manner as in Example 5, except that the cooling rate in the heating and de-oiling process was changed to 150°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The amount of material wound, L, measured with a length measuring device attached to the unwinding machine, was 1000m.

[0112] <Example 7> A 2116 series raw cloth was prepared using glass yarn of glass composition A, wound onto a Super Invar core with an outer diameter of Φ650 mm, and heated in a heating furnace at 400°C for 70 hours to remove oil (heating de-oiling process). The glass cloth was then cooled at a rate of 30°C / hour to return to room temperature. Next, a treatment solution (surface treatment type: amino) was prepared by dispersing 0.30% by mass of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane; SZ6032 (manufactured by Toray Dow Corning) in pure water adjusted to pH=3 with acetic acid. The cloth was immersed in the treatment solution at a line tension of 450 N / m (surface treatment agent coating process), squeezed with an NBR rubber roll at a pressure of 0.3 MPa, and then heated and dried at 130°C for 60 seconds to fix the silane coupling agent (fixing process). The dried cloth was sprayed at a rate of 3.0 kg / cm². 2 After high-pressure fiber separation, the glass cloth was dried at 130°C for 1 minute (drying process) and then wound up to obtain a roll of long glass cloth. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding length L, measured with a length measuring device attached to the unwinding machine, was 1000m.

[0113] <Example 8> A roll of long glass cloth was obtained in the same manner as in Example 7, except that the material was wound onto an aluminum-plated steel core with an outer diameter of Φ550 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 45°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0114] <Example 9> A 1035 series raw cloth was prepared using glass yarn of glass composition A, wound onto a Super Invar core with an outer diameter of Φ650 mm, and de-oiled by heating in a furnace at 400°C for 70 hours (heating de-oiling process). The glass cloth was then cooled at a rate of 30°C / hour to return to room temperature. Next, a treatment solution (surface treatment type: amino) was prepared by dispersing 0.30% by mass of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane; SZ6032 (manufactured by Toray Dow Corning) in pure water adjusted to pH=3 with acetic acid. The cloth was immersed in the treatment solution at a line tension of 350 N / m (surface treatment agent coating process), squeezed with an NBR rubber roll at a pressure of 0.3 MPa, and then heated and dried at 130°C for 60 seconds to fix the silane coupling agent (fixing process). The dried cloth was sprayed at a rate of 2.0 kg / cm². 2 After high-pressure fiber separation, the glass cloth was dried at 130°C for 1 minute (drying process) and then wound up to obtain a roll of long glass cloth. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding length L, measured with a length measuring device attached to the unwinding machine, was 1000m.

[0115] <Example 10> A roll of long glass cloth was obtained in the same manner as in Example 9, except that the material was wound onto an aluminum-plated steel core with an outer diameter of Φ550 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 45°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0116] <Example 11> A roll of long glass cloth was obtained in the same manner as in Example 2, except that glass yarn with glass composition B was used and a treatment solution (surface treatment type: amino) containing 0.30% by mass of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane; SZ6032 (manufactured by Toray Dow Corning) was used. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0117] <Example 12> A roll of long glass cloth was obtained in the same manner as in Example 5, except that glass yarn with glass composition B was used. This roll of long glass cloth was unwound using a winding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the winding machine, was 1000 m.

[0118] <Example 13> A roll of long glass cloth was obtained in the same manner as in Example 2, except that glass yarn with glass composition C was used and a treatment solution (surface treatment type: amino) containing 0.30% by mass of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane; SZ6032 (manufactured by Toray Dow Corning) was used. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0119] <Example 14> A roll of long glass cloth was obtained in the same manner as in Example 5, except that glass yarn with glass composition C was used. This roll of long glass cloth was unwound using a winding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the winding machine, was 1000 m.

[0120] <Example 15> A roll of long glass cloth was obtained in the same manner as in Example 1, except that the winding amount L, measured with a length measuring device attached to the unwinding machine, was 500 m. This roll of long glass cloth was unwound using the unwinding machine, and the surface and inner layers of the glass cloth were evaluated.

[0121] <Example 16> A roll of long glass cloth was obtained in the same manner as in Example 11, except that glass yarn with glass composition D was used. This roll of long glass cloth was unwound using a winding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the winding machine, was 1000 m.

[0122] <Comparative Example 1> A roll of long glass cloth was obtained in the same manner as in Example 1, except that the material was wound onto a SUS304 core with an outer diameter of Φ330 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 150°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0123] <Comparative Example 2> A roll of long glass cloth was obtained in the same manner as in Comparative Example 1, except that it was wound onto a core with an outer diameter of Φ550 mm during the heating and de-oiling process. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0124] <Comparative Example 3> A roll of long glass cloth was obtained in the same manner as in Comparative Example 1, except that it was wound onto an aluminum-plated steel core during the heating and de-oiling process. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0125] <Comparative Example 4> A roll of long glass cloth was obtained in the same manner as in Example 8, except that the material was wound onto a core with an outer diameter of Φ330 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 150°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0126] <Comparative Example 5> A roll of long glass cloth was obtained in the same manner as in Example 10, except that the material was wound onto a core with an outer diameter of Φ330 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 150°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0127] <Comparative Example 6> A roll of long glass cloth was obtained in the same manner as in Example 12, except that the material was wound onto a core with an outer diameter of Φ330 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 150°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0128] <Comparative Example 7> A roll of long glass cloth was obtained in the same manner as in Example 14, except that the material was wound onto a core with an outer diameter of Φ330 mm during the heating and de-oiling process, and the cooling rate during the heating and de-oiling process was changed to 150°C / hour. This roll of long glass cloth was unwound using an unwinding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the unwinding machine, was 1000 m.

[0129] <Comparative Example 8> A roll of long glass cloth was obtained in the same manner as in Comparative Example 6, except that glass yarn with glass composition D was used. This roll of long glass cloth was unwound using a winding machine, and the surface and inner layers of the glass cloth were evaluated. The winding amount L, measured with a length measuring device attached to the winding machine, was 1000 m.

[0130] The manufacturing conditions and evaluation results for the examples and comparative examples are shown in the table below.

[0131] [Table 2]

[0132] [Table 3]

[0133] [Table 4]

[0134] In Example 1, a glass cloth roll with minimal fluff was obtained over a long length, and no processing problems such as breakage or tearing occurred. In contrast, in Comparative Example 1, the entire roll had a lot of fluff, with some areas having even more fluff than others, resulting in a glass cloth roll of inconsistent quality. Furthermore, due to variations in the quality of the glass cloth within the roll, tearing occurred when the entire roll was processed under the same conditions.

Claims

1. A roll of long glass cloth wound around a core tube, The aforementioned glass cloth is composed of glass threads made up of multiple glass filaments as warp and weft threads, The roll-shaped long glass cloth has a tensile strength variation ratio Sb / Sa of 0.6 or more, where Sa is the larger of the tensile strength of the glass cloth located in the inner layer and the tensile strength of the glass cloth located in the outer layer of the roll-shaped long glass cloth, and Sb is the smaller of the tensile strength of the glass cloth located in the inner layer and the tensile strength of the glass cloth located in the outer layer of the roll-shaped long glass cloth, the outer layer is located at a position of 4% to 6% from the unwinding point relative to the winding amount L (m) of the glass cloth, and the inner layer is located at a position of 94% to 96% from the unwinding point relative to the winding amount L (m) of the glass cloth, in the roll-shaped long glass cloth.

2. The roll-shaped long glass cloth according to claim 1, wherein the bulk CTE of the glass constituting the glass cloth is 5 ppm / K or less.

3. The roll-shaped long glass cloth according to claim 1, wherein the bulk CTE of the glass constituting the glass cloth is 3.0 ppm / K or less.

4. The roll-shaped long glass cloth according to claim 1, wherein the bulk CTE of the glass constituting the glass cloth is 2.7 ppm / K or less.

5. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the bulk elastic modulus of the glass constituting the glass cloth is 60 GPa or more.

6. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the glass cloth is treated with a surface treatment agent containing a silane coupling agent.

7. The silane coupling agent is defined by the following formula (1): X (R) ３－ｎ Yes ｎ ・・・(1) The roll-shaped long glass cloth according to claim 6, comprising a compound represented by {Formula (1), where X is an organic group having at least one of an amino group and a radically reactive unsaturated double bond group, Y is independently an alkoxy group, n is an integer from 1 to 3, and R is independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group.}.

8. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the carbon content of the glass cloth is in the range of 0.01% by mass to 1.0% by mass.

9. The roll-shaped long glass cloth according to claim 8, wherein the absolute value of the difference in the carbon content of the glass cloth |Ca-Cb| is 0.028% by mass or less, where Ca is the amount of carbon content in the surface layer of the roll-shaped long glass cloth, and Cb is the amount of carbon content in the inner layer of the roll-shaped long glass cloth, the surface layer is located at a position of 4% to 6% from the unwinding point with respect to the winding length L (m) of the glass cloth, and the inner layer is located at a position of 94% to 96% from the unwinding point with respect to the winding length L (m) of the glass cloth.

10. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a tensile strength of 15 N / 25 mm or more.

11. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the outer layer have a tensile strength per unit thickness of 1.1 N / 25 mm / μm or more, which is determined by dividing the tensile strength by the thickness.

12. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the bulk CTE of the glass constituting the glass cloth is 0.1 ppm / K or more.

13. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the bulk CTE of the glass constituting the glass cloth is 1.0 ppm / K or more.

14. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the thickness of the glass cloth is 120 μm or less.

15. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a dielectric loss tangent value of 0.0080 or less at 10 GHz.

16. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a dielectric loss tangent value of 0.0060 or less at 10 GHz.

17. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein one or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a dielectric loss tangent value of 0.0042 or less at 10 GHz.

18. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the absolute value of the dielectric loss tangent difference of the glass cloth at 10 GHz |Dfa - Dfb| is 0.0004 or less, where Dfa is the dielectric loss tangent of the surface layer of the roll-shaped long glass cloth at 10 GHz, Dfb is the dielectric loss tangent of the inner layer of the roll-shaped long glass cloth at 10 GHz, the surface layer is located at a position of 4% to 6% from the unwinding point with respect to the winding amount L (m) of the glass cloth, and the inner layer is located at a position of 94% to 96% from the unwinding point with respect to the winding amount L (m) of the glass cloth.

19. One or both of the glass cloth located in the inner layer and the glass cloth located in the surface layer have a lightness (L ＊ A roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the value is 88 or more.

20. In the aforementioned roll-shaped long glass cloth, the absolute value of the brightness difference of the glass cloth is |L ＊ a-L ＊ b| is 1.5 or less, where L ＊ a is the lightness of the surface layer of the rolled long glass cloth, and L ＊ The roll-shaped long glass cloth according to claim 19, wherein b is the brightness of the inner layer of the roll-shaped long glass cloth, the surface layer is located at a position of 4% to 6% from the unwinding point relative to the winding amount L (m) of the glass cloth, and the inner layer is located at a position of 94% to 96% from the unwinding point relative to the winding amount L (m) of the glass cloth.

21. The roll-shaped long glass cloth according to any one of claims 1 to 4, wherein the tensile strength variation ratio Sb / Sa in the roll-shaped long glass cloth is less than 1.

0.

22. A roll of long glass cloth according to any one of claims 1 to 4, wherein the winding amount is 500 m or more.

23. A roll-shaped long glass cloth according to any one of claims 1 to 4, for use in printed circuit boards.

24. A roll-shaped long prepreg comprising a roll-shaped long glass cloth according to any one of claims 1 to 4 and a matrix resin impregnated in the glass cloth.

25. A winding core for heat-degreasing glass cloth, made of a material with a thermal expansion coefficient of 14 ppm / K or less at 0 to 100°C, and having an outer diameter of Φ500 mm or more at the winding section.

26. A method for manufacturing a roll of long glass cloth according to any one of claims 1 to 4, wherein the method is: Heating and degreasing the glass cloth, This includes cooling the glass cloth after the heat degreasing process, A method for manufacturing glass cloth that satisfies either or both of the following conditions (i) or (ii). (i) The heat degreasing is performed with the glass cloth wound around a core made of a material having a coefficient of thermal expansion of 14 ppm / K or less at 0 to 100°C and having an outer diameter of Φ500 mm or more at the winding portion. (ii) The cooling rate of the glass cloth in the above cooling is 70°C / h or less.

27. A method for manufacturing glass cloth according to claim 26, satisfying the condition of (i) above.

28. A method for manufacturing glass cloth according to claim 26 or 27, satisfying the conditions of (ii) above.

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