Glass cloth, prepreg and printed circuit board

Abstract

According to the present application, there are provided a quartz glass cloth constituted by a glass yarn having a high content of silicon dioxide (SiO2) and having less fuzz, and a prepreg and a printed circuit board, etc. containing the same. The glass cloth of the present application is constituted by a glass yarn containing a plurality of filaments as warp and weft, and the content of silicon (Si) of the glass yarn is 95.0 mass% or more and 100 mass% or less as converted into silicon dioxide (SiO2). The thickness (T) of the glass cloth is 80 μm or less, and satisfies {number of warp bundle segments (N) - 0.2} / thickness (T) [μm] < 0.056.

Description

Technical Field

[0001] This application relates to glass cloth, prepregs, and printed circuit boards, etc. This international application claims priority to Japanese Patent Application No. 2023-023729, filed on February 17, 2023, the entire contents of which are incorporated herein by reference. Background Technology

[0002] Currently, the high performance of information terminals such as smartphones and the high-speed communication represented by 5G are developing. Against this backdrop, especially for printed circuit boards (PCBs) used in high-speed communication, there is a desire not only to improve the long-sought-after high density, ultra-thinness, and heat resistance, but also to further improve the dielectric properties of the insulating materials (e.g., low dielectric loss tangent). Similarly, there is a desire to improve the dielectric properties of the prepregs used in the insulating materials of printed circuit boards, the glass cloth contained in the prepregs, and the glass yarns constituting the glass cloth.

[0003] For the purpose of improving the dielectric properties of prepregs, it is known to use a method of constructing the prepreg using low-dielectric glass. Patent documents 1 and 2 use glass yarn with a silica (SiO2) composition of 98–100% by mass. Furthermore, Patent document 3 describes a tufting agent for suppressing fuzzing of this glass yarn.

[0004] On the other hand, by performing a fiber-opening process on the glass cloth, air bubbles, known as voids, that exist in the prepreg and printed circuit board are less likely to be generated, thereby improving resin impregnation. It is known that by reducing voids and improving resin impregnation, the heat resistance and insulation of the printed circuit board can be improved; therefore, the fiber-opening process is important in the manufacturing process of glass cloth. Patent documents 4 and 5 describe fiber-opening techniques for glass cloth based on water pressure, such as water jetting, and fiber-opening techniques for glass cloth based on ultrasonic waves, etc.

[0005] Patent document 6 describes how, by setting the unevenness of the yarn width within a specific range, it is possible to reduce porosity and suppress pilling. Furthermore, patent document 7 describes how to improve the smoothness and resin impregnation of glass cloth using a fabric structure.

[0006] The IPC standard specifies various standards for the warp and weft density, filament diameter, and number of filaments, and glass cloth is usually woven according to these standards. Generally, it is known that using fine filament diameter yarns makes it easier to reduce the thickness of the glass cloth, and also ensures sufficient weave density, thus reducing the likelihood of problems such as mesh shift. Therefore, thin glass cloth is woven using fine filament diameter yarns.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2018-127747

[0010] Patent Document 2: Japanese Patent Application Publication No. 2018-127752

[0011] Patent Document 3: Japanese Patent Application Publication No. 2015-78079

[0012] Patent Document 4: Japanese Patent Application Publication No. 2009-263824

[0013] Patent Document 5: Japanese Patent Application Publication No. 2020-158945

[0014] Patent Document 6: Japanese Patent Application Publication No. 2022-181738

[0015] Patent Document 7: Japanese Patent Application Publication No. 2003-82562 Summary of the Invention

[0016] The problem the invention aims to solve

[0017] According to the research results of the inventors, in the prior art described in Patent Documents 1 to 7, there is room for further improvement in the fuzzing effect when using quartz glass with a high silica (SiO2) content. See below for details.

[0018] One of the purposes of this application is to provide a quartz glass cloth composed of glass yarn with high silica (SiO2) content and low fuzzing, as well as prepregs and printed circuit boards containing the same.

[0019] Solution for solving the problem

[0020] Some aspects of this application are illustrated in the following items[1] to

[16] .

[0021] [1] A type of glass cloth, which is a glass cloth composed of glass yarn containing multiple long filaments as warp and weft yarns.

[0022] The silicon (Si) content of the aforementioned glass yarn, calculated based on silicon dioxide (SiO2), is 95.0% to 100% by mass.

[0023] The aforementioned glass cloth has a thickness (T) of 80 μm or less and satisfies the following formula (A1):

[0024] {Number of warp bundle segments (N) - 0.2} / Thickness (T) [μm] < 0.056…(A1)

[0025] {In formula (A1), the number of warp bundle segments (N) is calculated by multiplying the warp filament diameter [μm] by the number of warp filaments [strands] ÷ the warp width [μm].}

[0026] [2] According to the glass cloth described in Project 1, when the glass cloth is embedded in epoxy resin and the epoxy resin is cured, and the cross-section of the glass cloth is observed, the warp bonding ratio calculated by the following formula is greater than 0 and less than 0.80.

[0027] Warp bonding ratio = number of bonding points of the warp filaments bonded to each other ÷ number of warp filaments.

[0028] [3] The glass cloth according to item 1 or 2 is treated with a surface treatment agent containing a silane coupling agent.

[0029] [4] The glass cloth according to item 3, wherein the aforementioned silane coupling agent comprises a compound represented by the following formula (C).

[0030] X(R) 3-n SiY n …(C)

[0031] {In formula (C), X is an organic group having at least one of an amino group and an unsaturated double bond group with free radical reactivity, Y is each independently an alkoxy group, n is an integer of 1 to 3, and R is each independently a group selected from the group consisting of methyl, ethyl, and phenyl.}

[0032] [5] The glass cloth according to Project 4, wherein X in the aforementioned formula (C) is an organic group having one or more methacryloyloxy or acryloyloxy groups.

[0033] [6] The glass cloth according to any one of items 1 to 5, wherein the average filament diameter (D) of the aforementioned glass yarn is 4 μm or more.

[0034] [7] The glass cloth according to any one of items 1 to 6, wherein when the thickness of the aforementioned glass cloth is 20 μm or more and 80 μm or less, the following formula (B1) is satisfied, and when the thickness of the aforementioned glass cloth is less than 20 μm, the following formula (B6) is satisfied.

[0035] 24 × average filament diameter (D) [μm] - thickness (T) [μm] > 96…(B1)

[0036] 14 × average filament diameter (D) [μm] - thickness (T) [μm] > 46…(B6)

[0037] [8] The glass cloth according to any one of items 1 to 7, wherein the thickness (T) of the aforementioned glass cloth is 60 μm or less.

[0038] [9] The glass cloth according to any one of items 1 to 8, wherein the loss on ignition of the aforementioned glass cloth is in the range of 0.01% to 0.30% by mass.

[0039]

[10] The glass cloth according to any one of items 1 to 9 is used for printed circuit boards.

[0040]

[11] A prepreg containing glass cloth, thermosetting resin and inorganic filler as described in any one of items 1 to 10.

[0041]

[12] A printed circuit board comprising the prepreg described in item 11.

[0042]

[13] An integrated circuit comprising the printed circuit board described in item 12.

[0043]

[14] An electronic device comprising the printed circuit board described in item 12.

[0044]

[15] A method for manufacturing glass cloth, wherein the aforementioned method includes:

[0045] The process of weaving glass yarn, which contains multiple long filaments and has a Si content ranging from 95.0% to 100% by mass (calculated as SiO2), as both warp and weft yarns to obtain glass cloth.

[0046] The aforementioned methods also include:

[0047] Before the aforementioned weaving process, the aforementioned glass yarn bundles are flattened, followed by a sizing and warping process; and

[0048] After the aforementioned warping process and before, during, or after the aforementioned weaving process, the following processes are also included:

[0049] The process of cleaning glass fiber with water at a temperature above 50°C;

[0050] The process of heating and degreasing the aforementioned cleaned glass yarn; and

[0051] In a liquid irradiated with ultrasound, the aforementioned glass yarn edge, which has been heated and degreased as described above, is transported at a speed of less than 50 m / min while being cleaned and split.

[0052] The thickness (T) of the glass cloth after the aforementioned fiber splitting treatment is less than 80 μm.

[0053] When the thickness of the glass cloth after the aforementioned fiber-opening treatment is 20 μm or more and 80 μm or less, the following formula (B1) is satisfied; when the thickness of the glass cloth after the aforementioned fiber-opening treatment is less than 20 μm, the following formula (B6) is satisfied:

[0054] 24 × average filament diameter (D) [μm] - thickness (T) [μm] > 96…(B1)

[0055] 14 × average filament diameter (D) [μm] - thickness (T) [μm] > 46… (B6).

[0056]

[16] The method according to item 15 further includes a step of surface treating the aforementioned glass cloth that has been cleaned and split using a surface treatment agent.

[0057] The effects of the invention

[0058] This application can provide quartz glass cloth composed of glass yarn with high silica (SiO2) content and low fuzzing, as well as prepregs and printed circuit boards containing it. Attached Figure Description

[0059] Figure 1 (a) and (b) are SEM images used to illustrate the calculation method of "adhesion ratio" in this application. Detailed Implementation

[0060] The following describes the implementation of this application, but this application is not limited thereto and various modifications can be made without departing from its spirit.

[0061] In this application, the numerical range recorded using "~" indicates a range of values ​​including the values ​​before and after "~" as both lower and upper limits. Furthermore, within a range of values ​​recorded in stages, the upper or lower limit of a certain numerical range can be replaced by the upper or lower limit of other numerical ranges recorded in stages. Moreover, the upper or lower limit of a certain numerical range can also be replaced by the values ​​shown in the embodiments. Furthermore, the term "process" not only includes independent processes, but also includes processes that achieve their function, even when they cannot be clearly distinguished from other processes.

[0062] Glass cloth

[0063] The glass cloth of this application comprises glass yarn containing multiple filaments as warp and weft yarns. The silicon (Si) content in the glass yarn, calculated as silicon dioxide (SiO2), is 95.0% by mass or more and 100% by mass or less, the thickness (T) of the glass cloth is 80 μm or less, and satisfies the following formula (A1):

[0064] {Number of warp bundle segments (N) - 0.2} / T[μm] < 0.056…(A1).

[0065] In formula (A1), "Number of warp bundle segments (N)" refers to the number of filament segments contained in the warp bundle of the glass cloth, calculated based on the warp filament diameter [μm], the number of warp filaments [roots], and the warp width [μm]. Regarding the glass cloth of this application, in a preferred embodiment, after the glass cloth is embedded in epoxy resin and the resin is cured, when the cross-section of the glass cloth is observed, the warp bonding ratio calculated using the following formula exceeds 0 and is less than 0.80.

[0066] Warp bonding ratio = Number of bonding points of warp filaments bonded to each other ÷ Number of warp filaments

[0067] The object to be embedded in epoxy resin can be at least a portion of the glass cloth.

[0068] As described in Patent Documents 1 and 2, glass with a high SiO2 content generally has low bending resistance and lacks flexibility even when in the form of glass cloth. Therefore, it is more prone to fuzzing and wrinkling compared to other glass types, which is a problem. Regarding this, Patent Document 1 describes a method to suppress prepreg fuzzing by surface-treating the glass cloth. Patent Document 2 describes a method to suppress glass cloth fuzzing by using glass yarn with a specified amount of paste attached. However, based on the research results of the inventors, it is known that the method in Patent Document 1 cannot suppress fuzzing that occurs before surface treatment, and there is room for improvement. Furthermore, it is known that in the methods described in Patent Documents 1 and 2, there is room for improvement, particularly in the resin impregnation of the glass cloth.

[0069] Patent Document 3 describes a method for suppressing fuzzing by using a glass fiber bundle agent with a specific composition. However, based on the research results of the inventors, it is known that the method in Patent Document 3 can suppress fuzzing without heating to remove oil or split the fibers. Therefore, from the viewpoint of the resin impregnation of the glass cloth, there is still room for improvement.

[0070] Patent Document 6 describes that yarns with finer filament diameters have lower mechanical strength and are more prone to pilling compared to yarns with coarser filament diameters, requiring fiber opening treatment under relatively mild conditions. Furthermore, Patent Document 6 describes pilling and voids occurring in areas with uneven yarn width (the uneven portion), and states that controlling the twist of the glass filaments, the bundling agent, and the tension during the weaving process can reduce yarn width unevenness, thereby reducing pilling and voids. However, Patent Document 6 only shows the effect on glass cloths with a thickness of 20 μm or less. The present inventors' research indicates that glass cloths with a thickness exceeding 20 μm have room for improvement in terms of pilling and voids (resin impregnation). Additionally, Patent Document 6 only lists E-glass, T-glass, S-glass, UT-glass, D-glass, NE-glass, and L-glass as glass types. The present inventors' research indicates that quartz glass with lower dielectric properties has room for improvement in terms of pilling and voids (resin impregnation).

[0071] Patent documents 4 and 5 describe fiber-opening techniques for glass cloth based on water pressure, such as water jetting, and fiber-opening techniques for glass cloth based on ultrasound, etc. By performing fiber-opening treatment on the glass cloth, porosity can be reduced and resin impregnation can be improved. However, the results of the inventors' research clearly show that glass cloth with a high SiO2 content in the glass constituting the glass yarn has lower mechanical strength compared to other glass types. Therefore, even for glass cloths thicker than 80 μm compared to those with mild fiber-opening conditions that have been studied and applied to date, the conventional fiber-opening treatments described in Patent documents 4 and 5 are prone to fuzzing. Furthermore, it is clear that quartz glass has high hardness and is not easily opened under mild fiber-opening conditions; therefore, fuzzing and porosity occur not only in areas of uneven yarn width but also in areas with less unevenness.

[0072] As a method other than physical processing, Patent Document 7 describes a method that reduces interlacing points and smooths the surface by using yarns with thicker filament diameters and lower weave density, thereby improving resin penetration. However, the inventors' research shows that there is room for improvement regarding napping and resin penetration.

[0073] In contrast, according to this application, glass cloth using glass yarn with a high silica (SiO2) content and suppressing fuzzing can be provided, as well as prepregs and printed circuit boards containing it. The glass cloth of this application, due to its high silica (SiO2) content, can improve the dielectric properties of the prepreg and printed circuit board (e.g., reduce the dielectric loss tangent). Furthermore, in a preferred embodiment, the glass cloth of this application has excellent resin impregnation properties, thus improving the heat resistance of its composite with the matrix resin, i.e., the prepreg and the printed circuit board.

[0074] While not limited by theory, the inventors conducted in-depth research on suppressing fuzzing in glass cloth when using quartz glass as glass yarn. Since warp yarns are less prone to fiber breakage than weft yarns, they focused on the number of filament segments (warp bundle segments) within the warp yarn bundles. They discovered that controlling this within a specified range can suppress fuzzing. As detailed below, reducing the number of warp bundle segments relative to thickness further suppresses fuzzing. Furthermore, in-depth research on suppressing fuzzing and improving resin impregnation in glass cloth when using quartz glass as glass yarn revealed that, since warp yarns are less prone to fiber breakage than weft yarns, they focused on the bonding ratio between filaments within the warp yarn bundles. They found that controlling both the number of filament segments (warp bundle segments) and the bonding ratio between filaments within a specified range can suppress fuzzing and improve resin impregnation. Lowering the warp bonding ratio improves resin impregnation. Furthermore, improved resin impregnation contributes to enhanced heat resistance of prepregs and printed circuit boards.

[0075] While not limited to a specific manufacturing method, in order to control the number of warp bundle segments within a specified range, the following operations are preferably included: using yarns with a filament diameter thicker than the thickness of the glass cloth; reducing the number of filaments; flattening the yarn bundles during warping and then performing sizing (applying sizing); and washing the glass cloth with water at a specified temperature or higher before heating and degreasing it. Furthermore, in order to control the number of warp bundle segments and the warp bonding ratio within a specified range, while not limited to a specific manufacturing method, the following operations are preferably included: based on the above methods, using ultrasonic waves to clean the combustion residue of the sizing agent and perform fiber opening treatment before surface treatment of the glass cloth; and controlling the glass cloth transport speed to below a specified speed.

[0076] [Glass yarn]

[0077] The glass yarn constituting the glass cloth is obtained from glass with a Si content ranging from 95.0% to 100% by mass (calculated as SiO2). By using this glass yarn, the dielectric properties of the resulting glass cloth can be improved. The Si content, calculated as SiO2, is preferably in the range of 98.0% to 100% by mass, more preferably 99.0% to 100% by mass, even more preferably 99.5% to 100% by mass, and particularly preferably 99.9% to 100% by mass.

[0078] The average filament diameter (also simply referred to as "filament diameter") of the glass filaments constituting the glass yarn is preferably 4.0 μm or more and 11.0 μm or less. The lower limit of the filament diameter is more preferably 4.5 μm or more, further preferably 5 μm or more, and particularly preferably 5.5 μm or more. The upper limit of the filament diameter that can be combined with these lower limits is more preferably 10.0 μm or less, further preferably 9.5 μm or less. Furthermore, in order to satisfy formula (A1), although it also depends on the number of filaments, the filament diameter is preferably 5.0 μm or more, more preferably 5.5 μm or more, and particularly preferably 6.0 μm or more. If the filament diameter is above the aforementioned lower limit, the breaking strength of the filaments is higher, and therefore, the resulting glass cloth is less prone to fuzzing. If the filament diameter is below the aforementioned upper limit, the mass of the glass cloth is smaller, and therefore, it is easier to handle or process. In addition, if the filament diameter is within the above range, it is easier to obtain the effects of suppressing fuzzing and improving resin impregnation. When referred to as "average filament diameter" (or "filament diameter") in this application, it refers to the average filament diameter (D) of the filaments that constitute only the warp yarns. MD ) or the average filament diameter (D) of the filaments that constitute only the weft yarn TD The average filament diameter (D) is not obtained by combining the warp and weft yarns.

[0079] The average filament diameter (D) is calculated as follows, based on the average filament diameter (D) of the warp yarns. MD ) and the average filament diameter of the weft yarn (D TD The value calculated from this.

[0080] D=(D MD +D TD ) / 2

[0081] The average filament diameter (D) is preferably 4.0 μm or more and 11.0 μm or less. The lower limit of the average filament diameter (D) is preferably 4.0 μm or more, more preferably 4.5 μm or more, further preferably 5 μm or more, and particularly preferably 5.5 μm or more. The upper limit of the filament diameter (D) that can be combined with these lower limits is more preferably 10.0 μm or less, and further preferably 9.5 μm or less. Furthermore, to satisfy formula (A1), although it also depends on the number of filaments, the filament diameter (D) is preferably 5.0 μm or more, more preferably 5.5 μm or more, and particularly preferably 6.0 μm or more. If the filament diameter (D) is above the aforementioned lower limit, the breaking strength of the filaments is higher, and therefore, the resulting glass cloth is less prone to fuzzing. If the filament diameter (D) is below the aforementioned upper limit, the mass of the glass cloth is smaller, and therefore, it is easier to handle or process. Furthermore, if the filament diameter (D) is within the aforementioned range, it is easier to obtain the effects of suppressing fuzzing and improving resin impregnation.

[0082] The average number of glass filaments constituting the glass yarn (also simply referred to as "filament count") is preferably 10 to 250, more preferably 15 to 200, even more preferably 18 to 150, and particularly preferably 20 to 120. By having a filament count of 10 or more, there is a tendency to suppress yarn breakage. In addition, if the average number of glass filaments is within the above range, it is easy to obtain the effects of suppressing fuzzing and improving resin penetration. In particular, in order to satisfy formula (A1), although it also depends on the filament diameter, it is preferable to set the number of glass yarn filaments used in the warp to be 150 or less, more preferably 120 or less, and particularly preferably 100 or less. In this application, the average number of filaments is the average value of the glass yarn filaments constituting only the warp or the average value of the glass yarn filaments constituting only the weft, and is not an average value obtained by combining both warp and weft yarns.

[0083] [Weaving structure, etc.]

[0084] Glass cloth is constructed using glass yarn containing multiple glass filaments as both warp and weft. Examples of glass cloth weave structures include plain weave, square weave, satin weave, and twill weave. Plain weave is preferred.

[0085] The weave density (weave density) of the warp and weft yarns constituting the glass cloth is preferably 10 yarns / inch to 120 yarns / inch (= 10 to 120 yarns / 25.4 mm), and more preferably 40 yarns / inch to 120 yarns / inch. If the weave density is within the above range, it is easy to obtain the effect of suppressing pilling and improving resin penetration.

[0086] The preferred unit area weight (mass of the glass cloth) is 8 g / m². 2 ~90g / m 2 More preferably 8g / m 2 ~80g / m 2 Further preferred is 8g / m 2 ~70g / m 2 The preferred value is 8g / m 2 ~60g / m 2 If the weight per unit area of ​​the glass cloth is within the above range, it is easy to achieve the effects of suppressing fuzzing and improving resin impregnation.

[0087] The thickness (T) of the glass cloth is greater than 0 μm and less than 80 μm. The upper limit of the thickness (T) is preferably less than 60 μm, more preferably less than 55 μm, and even more preferably less than 50 μm. If the thickness of the glass cloth is within the above range, it is easy to obtain the effects of suppressing fuzzing and improving resin impregnation. The lower limit of the thickness (T) of the glass cloth that can be combined with these upper limits is preferably more than 5 μm, more than 10 μm, more than 15 μm, or more than 20 μm.

[0088] [Number of warp bundle segments]

[0089] The thickness (T) of the glass cloth and the number of warp bundle segments (N) satisfy the following formula (A1). When the thickness of the glass cloth and the number of warp bundle segments satisfy the following formula (A1), the portion of the filaments overlapping in layers in the warp yarns is reduced relative to the thickness, and the unevenness of the glass cloth surface and the yarn bundles is made more uniform, thereby suppressing fuzzing. In addition, the portion of the filaments overlapping in layers in the warp yarns to form gaps is reduced relative to the thickness, which improves resin impregnation.

[0090] {Number of warp bundle segments (N) - 0.2} / T[μm] < 0.056…(A1)

[0091] Regarding glass cloth, the warp yarns, which bear tension during handling, are less prone to fiber breakage. Compared to the weft yarns, they are more likely to develop unevenness and gaps in the yarn bundles, resulting in a tendency for pilling and voids. Therefore, adjusting the number of warp yarn bundle segments is effective in suppressing pilling and improving resin penetration.

[0092] The number of warp bundle segments (N) is determined as shown below by the warp width [μm] and the diameter of the warp filaments (D). MD The value is calculated from [μm] and the number of warp filaments [threads].

[0093] Number of warp bundle segments (N) = Diameter of warp filament (D) MD [μm] × number of warp filaments [lengths] ÷ warp width [μm]

[0094] Here, it is preferable to satisfy formula (A1) by setting a large filament diameter, a small number of filaments, flattening the yarn bundle before sizing during warping, and washing the glass cloth with water above 50°C before heating and degreasing it.

[0095] The relationship between the thickness (T) (μm) of the glass cloth and the number of warp bundle segments (N) preferably satisfies formula (A2), more preferably satisfies formula (A3), even more preferably satisfies formula (A4), and particularly preferably satisfies formula (A5).

[0096] {N-0.2} / T[μm]<0.054…(A2)

[0097] {N-0.2} / T[μm]<0.052…(A3)

[0098] {N-0.2} / T[μm]<0.050…(A4)

[0099] {N-0.2} / T[μm]<0.048…(A5)

[0100] [Warp bonding ratio]

[0101] The warp bonding ratio is as follows, and it is a value calculated based on the number of warp filaments and the number of bonding points of the filaments that are bonded to each other.

[0102] Warp bonding ratio = Number of bonding points of warp filaments bonded to each other ÷ Number of warp filaments

[0103] The number of bonding points, as detailed in the first section of the examples, is determined by observing the cross-section of the glass cloth after it has been embedded in epoxy resin and cured. The warp bonding ratio of the glass cloth in this application, calculated using the above formula, is preferably greater than 0 and less than 0.80. More preferably, the warp bonding ratio is greater than 0 and less than 0.70, and even more preferably greater than 0 and less than 0.60.

[0104] Glass cloth with a warp bonding ratio less than a specified value does not easily hinder resin penetration between multiple filaments, thus achieving good resin impregnation. Here, in order to control the warp bonding ratio and formula (A1) simultaneously, based on the aforementioned adjustments to the diameter and number of filaments, the flattening treatment of the yarn bundles, and the cleaning of the sizing agent, examples can be listed such as: cleaning the combustion residue of the sizing agent and performing fiber opening treatment using ultrasound before surface treatment of the glass cloth; and controlling the number of bonding points of the filaments by controlling the transport speed of the glass cloth to below a specified speed.

[0105] In the above formula, "filaments bonded to each other" also includes any of the following situations: a glass filament is in contact with other glass filaments; a surface treatment layer in a glass filament is in contact with other glass filaments; and a surface treatment layer in a glass filament is in contact with surface treatment layers in other glass filaments.

[0106] The "epoxy resin" used to determine the warp bonding ratio is a resin for which the aforementioned bonding ratio can be calculated in accordance with the spirit of this application; more specifically, the resin described in the examples is used. In cases where it is unavailable, an epoxy resin capable of curing under static conditions is used.

[0107] Figure 1(a) and (b) are SEM images used to illustrate the calculation method of the "bonding ratio" in this application. In the figures, epoxy resin is represented in black, and the cross-section of the filament is represented by a white circle.

[0108] Figure 1 In (a), the area indicated by arrow a1 is the bonding point between the filaments, while the area indicated by arrow a2 is not. Here, when observing the cross-section of the glass cloth at 2000x magnification using a scanning electron microscope, the area where the cross-sections of the filaments are in contact with each other (i.e., the circular white dots representing the cross-sections of the filaments in the SEM image) for more than 50 nm is defined as the "bonding point".

[0109] In this application, the "total number of filaments" and "number of bonding points" are defined as the number of filaments whose entire cross-section falls within the observation image. Filaments whose cross-section is not visible in the observation image, and the bonding points provided by such filaments, are not counted in the "total number of filaments" and "number of bonding points." Figure 1 Taking (b) as an example, the total number of filaments whose entire cross-section falls within the observation image is 30 (refer to the numbers in white). There are a total of 18 bonding points where these filaments are in contact with each other (refer to the "×" markings). Filaments not visible in the observation image are not counted in the "total number of filaments" and "number of bonding points". Therefore, in Figure 1 In example (b), the bonding ratio is calculated to be 18 / 30 = 0.6.

[0110] It should be noted that, on average from several cross sections, the warp bonding ratio of the glass cloth is preferably greater than 0 and less than 0.80, and there may be cross sections that do not meet this warp bonding ratio.

[0111] [Filament diameter and glass cloth thickness]

[0112] The glass cloth preferably uses glass yarn with a diameter thicker than the thickness of the glass cloth, for example, glass yarn thicker than the filament diameter specified in the IPC standard. More specifically, when the thickness of the glass cloth is 20 μm or more and 80 μm or less, the average filament diameter (D) (μm) of the glass yarn constituting the glass cloth and the thickness (T) (μm) of the glass cloth preferably satisfy the following formula (B1), more preferably the following formula (B2), and particularly preferably the following formulas (B3), (B4), or (B5). When the thickness of the glass cloth is less than 20 μm, it preferably satisfies the following formula (B6), more preferably the following formula (B7), and particularly preferably the following formula (B8) or (B9).

[0113] 24×DT>96…(B1)

[0114] 24×DT>98…(B2)

[0115] 24×DT>100…(B3)

[0116] 24×DT>104…(B4)

[0117] 24×DT>108…(B5)

[0118] 14×DT>46…(B6)

[0119] 14×DT>48…(B7)

[0120] 14×DT>50…(B8)

[0121] 14×DT>52…(B9)

[0122] Therefore, compared to the thickness of the glass cloth, the strength of each filament is increased, which can suppress the occurrence of fuzzing.

[0123] [Filament diameter and number of filaments]

[0124] The glass cloth preferably uses glass yarn with a thicker filament diameter and fewer filaments compared to its thickness. The number of warp bundle segments is not particularly limited by filament diameter and number of strands, as long as formula (A1) is satisfied. Preferably, the number of filaments with a thickened filament diameter is such that the TEX of the glass yarn is at a previous level, for example, the same level as the TEX specified in the IPC standard, or the cross-sectional area of ​​the glass yarn (cross-sectional area of ​​one filament × number of filaments) is set at a previous level, for example, the same level as the cross-sectional area of ​​the yarn specified in the IPC standard. Here, "same level" means allowing a difference of ±30% or ±20%. This ensures sufficient weave density relative to thickness and reduces the likelihood of mesh shifting or other problems.

[0125] [Silane coupling agent]

[0126] From the viewpoint of improving resin impregnation, the glass yarn (including glass filaments) constituting the glass cloth is preferably surface-treated with a surface treatment agent. The surface treatment agent for the glass yarn preferably contains a silane coupling agent. As a silane coupling agent, for example, a silane coupling agent represented by the following formula (C) is preferably used.

[0127] X(R) 3-n SiY n …(C)

[0128] {In formula (C), X is an organic group having at least one of an unsaturated double bond group and an amino group that is reactive with free radicals, such as a carbon-carbon double bond group that is reactive with free radicals, Y is independently an alkoxy group, n is an integer of 1 to 3, and R is a group selected from the group consisting of methyl, ethyl, and phenyl.}

[0129] As a reason for the increase in the dielectric loss tangent of the glass cloth, it can be assumed that:

[0130] (i) residual, trace amounts of thermally oxidized sizing agent that remain physically attached to the surface of the glass fiber; and

[0131] (ii) It does not form chemical bonds with the glass surface but rather undergoes physical adhesion, and the residue of the surface treatment agent or its modifications cannot be reduced by water-based cleaning.

[0132] From the viewpoint of suppressing the occurrence of (i) thermal oxidative degradation products and / or suppressing the occurrence of (ii) residues or modifications, X in formula (C) is preferably an organic group that does not form a salt with ionic compounds. Furthermore, from the viewpoint of reactivity with the matrix resin, X in formula (C) is more preferably an organic group having one or more methacryloyloxy or acryloyloxy groups.

[0133] Regarding Y in the above formula (C), as an alkoxy group, for the purpose of stabilizing the glass cloth, it is preferably an alkoxy group with 1 to 5 carbon atoms (1, 2, 3, 4 or 5 carbon atoms).

[0134] As a surface treatment agent, the silane coupling agent shown in formula (C) can be used alone or in combination with two or more silane coupling agents different from X in formula (C). Examples of silane coupling agents shown in formula (C) include, for example, vinyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 5-hexenyltrimethoxysilane, and mixtures thereof.

[0135] The molecular weight of the silane coupling agent is preferably 100-600, more preferably 150-500, and even more preferably 200-450. Particularly preferred are the use of two or more silane coupling agents with different molecular weights. By using two or more silane coupling agents with different molecular weights to treat the glass yarn surface, there is a tendency for the density of the treatment agent at the glass surface to increase, and for the reactivity with the matrix resin to be further enhanced.

[0136] From the viewpoint that it is difficult to suppress the reactivity with resin, silane coupling agents are preferably nonionic. Among nonionic silane coupling agents, those having at least one group selected from the group consisting of vinyl, methacryloxy, and acryloyloxy groups are preferred, and those having at least one methacryloxy or acryloyloxy group are particularly preferred. Since the reactivity with resin is not impaired, the heat resistance and reliability of the printed circuit board can be improved.

[0137] In one embodiment, X in formula (C) is an organic group having at least one of the aforementioned unsaturated double bond group and amino group. Therefore, not only does X have both the aforementioned unsaturated double bond group and amino group, but also any embodiment having the aforementioned unsaturated double bond group but not having the aforementioned amino group, and any embodiment not having the aforementioned unsaturated double bond group but having the aforementioned amino group, falls within the scope of formula (C). Preferably, X in formula (C) is the aforementioned unsaturated double bond group, and preferably does not contain an amino group.

[0138] [Loss on Ignition]

[0139] The weight loss on ignition of the glass cloth is preferably in the range of 0.01% to 0.30% by mass. More preferably, it is 0.02% to 0.26% by mass, even more preferably, it is 0.03% to 0.22% by mass, even more preferably, it is 0.03% to 0.18% by mass, and particularly preferably, it is in the range of 0.03% to 0.16% by mass. Although it also depends on the thickness of the glass cloth, if the weight loss on ignition is less than 0.30% by mass, the amount of silane coupling agent chemically bonded to the surface of the glass cloth will not become excessive. In this case, the dielectric loss tangent of the glass cloth, and consequently the dielectric loss tangent of the resulting printed circuit board, is easily reduced. In addition, if the weight loss on ignition is 0.01% by mass or more, the heat resistance of the resulting printed circuit board is less likely to deteriorate.

[0140] Manufacturing Method of Fiberglass Cloth

[0141] The method for manufacturing glass cloth according to this application includes: a process of weaving glass yarn containing multiple filaments and having a Si content in the range of 95.0% to 100% by mass (calculated as SiO2) as warp and weft yarns to obtain glass cloth (weaving process). The method further includes: a warping process in which the glass yarn is straightened and flattened before the above weaving process, and then coated with a sizing agent; a process in which the glass yarn before heating and degreasing is cleaned with water at 50°C or higher after the above warping process and before, during, or after the above weaving process (cleaning process before heating and degreasing); and a process in which the glass yarn is then heated and degreased (heating and degreasing process). As a result, the number of warp bundle segments and the thickness of the glass cloth can be adjusted in a manner that satisfies formula (A1), and a quartz glass cloth with less fuzz can be provided. The method may also include: a process in which the cleaned and heated and degreased glass yarn edge is transported in a liquid irradiated with ultrasonic waves at a speed of 50 m / min or less for cleaning and fiber opening (cleaning and fiber opening process). Therefore, by adjusting the number of warp bundle segments and thickness of the glass cloth to satisfy formula (A1) and the warp bonding ratio to a specified value or below, a quartz glass cloth with less fuzzing, excellent resin impregnation, and improved heat resistance of printed circuit boards and the like can be provided.

[0142] The aforementioned glass processing method (pre-heating degreasing cleaning step, heating degreasing step, and cleaning and fiber-opening step) can be applied to glass yarn before weaving, and also to woven glass cloth. In other words, the process of weaving glass yarn to obtain glass cloth can be set before, during, or after the glass processing method. It should be noted that in the glass processing method, "reduction" refers to the aim of removing, for example, at least a portion of the sizing agent or silane coupling agent, and residual substances may remain. Hereinafter, an example is given including the warping step, weaving step, pre-heating degreasing cleaning step, heating degreasing step, and cleaning and fiber-opening step in sequence. However, the manufacturing method of the glass cloth of this application is not limited to this.

[0143] [The warping process of glass yarn]

[0144] The warping process of glass yarn includes: using glass yarn with a Si content ranging from 95.0% to 100% by mass (calculated as SiO2), flattening the yarn bundle, and then sizing the glass yarn. This treatment allows for sizing while the yarn width is increased, thus facilitating the widening of the yarn width in the woven glass cloth state. This allows for control of the number of warp bundle segments and thickness of the resulting glass cloth in accordance with formula (A1), suppressing pilling. In other words, the unevenness of the glass cloth surface and the yarn bundles is suppressed, making pilling less likely. The method for flattening the glass yarn bundle is not particularly limited; examples include processing under pressure using rollers. From the viewpoint of suppressing pilling and flattening the yarn bundle, the pressure is preferably 1.0 kg / cm. 2 ~6.0kg / cm 2 More preferably 2.0 kg / cm 2 ~5.0kg / cm 2 A further preferred value is 2.5 kg / cm². 2 ~5.5kg / cm 2 In addition, this warping process makes it easy to remove the paste from the pre-heating and degreasing cleaning process described later.

[0145] [Weaving process of glass cloth blank]

[0146] In the weaving process of glass cloth prefabricated fabric, glass yarn with a Si content in the range of 95.0% to 100% by mass (calculated as SiO2) can be woven into the warp yarn prepared by the warping process of glass yarn using a loom. This allows the production of glass cloth prefabricated fabric, for example, as a plain weave structure. To suppress fuzzing during spinning and warping of the glass yarn, the glass yarn used in the glass cloth prefabricated fabric is preferably surface-treated using a sizing agent with starch, polyvinyl alcohol, or similar components. It should be noted that in this application, "glass cloth prefabricated fabric" refers to glass cloth before heat degreasing.

[0147] The glass yarn used in the aforementioned processes, namely the warping process of the glass yarn and the weaving process of the glass cloth fabric, is preferably a glass yarn with a diameter thicker than the thickness of the resulting glass cloth, for example, a glass yarn with a filament diameter thicker than that specified in the IPC standard. More specifically, depending on the target thickness of the glass cloth, it is preferable to use glass yarn with a filament diameter that satisfies at least one of the above formulas (B1) to (B9). This makes it easier to suppress fuzzing and improve resin penetration. Furthermore, the glass yarn used in the aforementioned processes is preferably one with a TEX or cross-sectional area that is conventional compared to the thickness of the resulting glass cloth, for example, the TEX or cross-sectional area specified in the IPC standard. This ensures sufficient weave density compared to the thickness and prevents problems such as mesh shift.

[0148] [Cleaning process before heating and degreasing]

[0149] The pre-heat degreasing cleaning process includes cleaning the glass cloth before heat degreasing with water at 50°C or higher to reduce the amount of paste. This reduces adhesion caused by the paste in the filaments and the combustion residue of the paste during heat degreasing, allowing control over the number of warp bundle segments and thickness of the resulting glass cloth to satisfy formula (A1). Furthermore, it facilitates fiber opening treatment of the glass cloth with the warp adhesion ratio below a predetermined value. From the viewpoint of cleaning efficiency, water is preferably used as the cleaning solvent in this process, and the temperature is preferably 50°C or higher. By using water at 50°C or higher, the amount of paste necessary for protecting the glass yarn up to the heat degreasing process is retained, and excess paste is washed away. The water temperature is preferably 50°C or higher and lower than 100°C. The lower limit of the water temperature is more preferably 55°C or higher, further preferably 60°C or higher, and even more preferably 65°C or higher. The upper limit of the water temperature that can be combined with these lower limits is more preferably 95°C or lower, and further preferably 90°C or lower. The solvent used for cleaning is not particularly limited, but from the viewpoints of safety and cost, cleaning with water, reverse osmosis (RO) water, or ion-exchanged water is preferred. The cleaning method for the glass cloth blank is not particularly limited; methods such as ultrasonic cleaning (e.g., using an ultrasonic transducer), spray-based spraying (e.g., high-pressure spraying), and steam spraying are acceptable. From the viewpoint of cost-effective processing, the following method is preferred: immersing the glass cloth blank in a tank containing a cleaning solution, removing excess cleaning solution using a squeeze roller, and then drying the glass cloth blank. In this case, the immersion time can be, for example, 2 seconds or more, 5 seconds or more, 10 seconds or more, or 15 seconds or more but less than 120 seconds, 90 seconds or less, 60 seconds or less, or 45 seconds or less.

[0150] [The process of reducing the sizing agent (heating and degreasing process)]

[0151] The process of reducing sizing agent can include, for example, a degumming process (heat degreasing process) that heats the glass cloth blank at a temperature of 600°C to 1600°C. This facilitates the reduction of sizing agent from the glass. By reducing the trace amounts of thermally oxidized deteriorated sizing agent residue remaining physically adhered to the glass surface, the increase in the dielectric loss tangent of the resulting glass cloth can be easily and effectively suppressed.

[0152] In the heat degreasing method for glass cloth blanks, the glass cloth blanks can be heat-degreased at a temperature of 600°C or higher. This easily reduces the dielectric loss tangent of the resulting glass cloth. The heat degreasing temperature is preferably 600°C or higher and 1600°C or lower, more preferably 800°C or higher and 1300°C or lower, and even more preferably 900°C or higher and 1100°C or lower. If the heat degreasing temperature is 600°C or higher, it is easy to thoroughly remove residues of paste adhering to the glass cloth after heat degreasing, thus easily reducing the dielectric loss tangent of the glass cloth. On the other hand, if the heat degreasing temperature is 1500°C or lower, it is easy to suppress devitrification of the glass, effectively preventing a decrease in the strength of the glass cloth.

[0153] The heating time can be appropriately selected, preferably 1 second or more and 10 minutes or less. As an upper limit for the heating time, 5 minutes or less is more preferred, further preferably 2 minutes or less, and particularly preferably 90 seconds or less. From the perspective of performing heat treatment at high temperatures, if the heating time is 10 minutes or less, the damage to the glass cloth is reduced, and problems such as localized openings or breakage of the glass cloth during processing are less likely to occur. From the viewpoint of effectively removing residues of the paste, the lower limit of the heating time, which can be combined with these upper limits, can more preferably be 5 seconds or more, 10 seconds or more, or 15 seconds or more.

[0154] Regarding the means of heating the glass cloth blank, as long as the heating is carried out in a manner that sets the degreasing temperature to within the range of 600°C to 1600°C, known heating methods, heating media, heating mechanisms, heating devices, and heating components can be used. Heating methods may include, for example, (1) heating the glass cloth blank in a heating furnace; (2) bringing the glass cloth blank into contact with the heating element; or (3) blowing high-temperature steam onto the glass cloth blank. By heating the glass cloth blank in a manner that sets the degreasing temperature to 600°C or higher, organic matter adhering to the surface of the glass cloth blank can be removed efficiently or the removal time of organic matter can be shortened. The heating of the glass cloth blank can be carried out sequentially or continuously in a closed system or an open system, or a combination of closed and open systems can be used.

[0155] In a closed system, from the viewpoint of suitable heating based on the heating method, it is preferable to place the glass cloth blank inside the heating furnace, and / or, from the viewpoint of storage space and heating range, it is preferable to store and heat the glass cloth blank in a wound state. Furthermore, from the viewpoint of improving the removal efficiency of organic matter or shortening the removal time of organic matter, it is also preferable to heat the glass cloth blank while handling it inside the heating furnace.

[0156] In an open system, from the perspective of the heated area, it is preferable to heat the glass cloth blank while it is being transported. The transport of the glass cloth blank can be carried out using, for example, a winding mechanism and a take-up mechanism, or a roller-to-roll method.

[0157] (Heating furnace)

[0158] As for heating methods in a heating furnace, any method that can achieve a heating temperature of 600℃ to 1600℃ can be considered, including electric heaters, burners, and other similar means; it is not limited to a specific method. Furthermore, multiple methods can be combined for heating, with gas-fired single-radiant tube burners or electric heaters being preferred.

[0159] From the perspective of heating efficiency, the heating furnace preferably has means for venting the gas generated inside the furnace and / or means for air circulation. Gas venting means can be, for example, nozzles, gas pipes, orifices, degassing valves, etc. Air circulation means can be, for example, blades, air conditioning equipment, etc.

[0160] To efficiently remove organic matter adhering to the surface of the glass cloth blank, a continuous method that allows the edge of the glass cloth blank to be continuously fed into the heating furnace for heating is preferred over an intermittent method that involves winding the glass fiber fabric into a core and heating the glass cloth blank at a specified atmosphere temperature. Furthermore, a method that allows for continuous cleaning of the glass cloth (glass cloth blank) before heating and degreasing is particularly preferred.

[0161] (Contact component used to heat glass cloth blank)

[0162] As a method for heating glass cloth blanks, the aforementioned heating furnace can be used. From the viewpoint of low operating costs, the glass cloth blanks can be heated by bringing a component heated to a specified temperature into contact with the glass cloth blanks.

[0163] If the glass cloth blank can be heated to a temperature range of 600°C to 1600°C for degreasing, the shape of the contact member is not particularly limited, but a roller shape is preferred for ease of handling the glass cloth blank. As a member capable of heating the glass cloth blank in a roller shape, a roller that can be used in a high-temperature region and has minimal temperature deviation in the width direction, and which heats by induction heating, is preferred. When heating the glass cloth blank using the contact member, it can be assumed that the temperature of the contact member is approximately equal to the surface temperature of the glass cloth blank.

[0164] As the glass cloth blank is continuously heated, in order to remove the carbides adhering to the heating roller, the heating roller method is preferably equipped with a mechanism for removing the adhering foreign matter, such as a scraper.

[0165] (Methods of applying high-temperature steam to glass cloth blanks (steam application methods))

[0166] The vapor used in the glass cloth fabric can include, for example, volatile solvents, water vapor, or gases other than water vapor. From the viewpoint of toxicity to human health and ease of promoting the decomposition of the slub used in glass fibers, water vapor is preferred. Regarding the temperature of this high-temperature vapor, to maintain the surface temperature of the glass cloth fabric in the range of 600°C to 1600°C, a method capable of supplying high-temperature vapor and heated air in any proportion can be used, if necessary. The temperature of the high-temperature vapor is 500°C or higher, preferably 600°C or higher, more preferably 700°C or higher, further preferably 800°C or higher, and particularly preferably 900°C or higher. The means of applying the vapor is not limited and can include spraying, spray diffusion, jet nozzles, etc. Alternatively, sometimes the gas discharged from the heating furnace is reused as high-temperature vapor.

[0167] (Heating and degreasing device for glass cloth blank)

[0168] As described above, the heating and degreasing device for glass cloth blanks can heat the glass cloth blanks at a degreasing temperature ranging from 600°C to 1600°C. More specifically, the heating and degreasing device for glass cloth blanks preferably includes a heating furnace, which has a winding mechanism and a winding mechanism, and is capable of carrying out the process of heating the glass cloth blanks at a degreasing temperature ranging from 600°C to 1600°C while transporting them.

[0169] The winding and unwinding mechanisms can be, for example, at least one pair of rollers, roller-to-roll, etc. The heating furnace, air circulation means, contact components, and steam application means are as described in the above-described heat treatment process for glass cloth blanks.

[0170] From a production efficiency point of view, it is preferable to include a cleaning device for washing off the sizing agent of the glass cloth blank immediately in front of the heating furnace.

[0171] [Fiber opening process of glass cloth]

[0172] The fiber-opening process of the glass cloth after heat degreasing includes: a process of opening the glass cloth so that the number of warp bundle segments and the thickness of the resulting glass cloth satisfy formula (A1) and the warp bonding ratio is below a specified value. This fiber-opening process improves the resin's permeability in the glass cloth. Examples of this fiber-opening process include, for instance, applying water pressure to the glass cloth; fiber-opening based on high-frequency vibration using water (e.g., degassed water, ion-exchanged water, deionized water, electrolyzed cation water, or electrolyzed anion water, etc.) as a medium; and processing under roller pressure. This fiber-opening process can be performed simultaneously with weaving or after weaving. It can be performed before or after heat degreasing, or simultaneously with heat degreasing, or simultaneously with or after the surface treatment process.

[0173] From the viewpoint of controlling the number of warp bundles and the warp bonding ratio of glass cloth with a thickness of 80 μm or less, made of glass yarn with relatively thick filaments that satisfy any of the above formulas (B1) to (B9), to a specified range, the fiber-opening process is preferably a process in which the glass cloth is washed and opened while being transported in a liquid after the heating and degreasing process and before the surface treatment process. Furthermore, the transport speed of the glass cloth in this process is preferably 50 m / min or less. Glass yarn with thick filaments is difficult to open, especially glass yarn with high glass hardness such as quartz glass. By washing and opening the glass cloth after the heating and degreasing process and before the surface treatment process, the combustion residue from the heating and degreasing process can be removed, preventing adhesion between filaments caused by the combustion residue acting as an adhesive. In addition, by opening the fiber before the surface treatment, adhesion between filaments during the surface treatment process can also be prevented. Therefore, the warp bonding ratio of the glass cloth can be controlled in a way that satisfies the specified range, improving resin impregnation. It does not simply use strong processing force to open the fibers, but can open the fibers easily, and therefore is not prone to pilling.

[0174] The preferred method for cleaning and fiber-opening the glass cloth is to irradiate the glass cloth with ultrasonic waves in a liquid after the heating and degreasing process and before the surface treatment process. This process primarily removes the combustion residue from the heating and degreasing process and then opens the fiber (ultrasonic cleaning). Alternatively, the preferred method is to process the glass cloth by roller-to-roller transport in a liquid irradiated with ultrasonic waves using an ultrasonic oscillator.

[0175] Water or organic solvents can be used as the liquid in ultrasonic cleaning, but from the perspective of safety and environmental protection, liquids with water as the main component are preferred. To improve cleaning efficiency, surfactants and pH adjusters can also be added to the liquid.

[0176] There is no particular limitation on the temperature of the liquid used in ultrasonic cleaning, but from the viewpoint of improving cleaning effect, it is preferably 5°C or higher. Furthermore, from a safety perspective, the temperature of the liquid used in cleaning is preferably 60°C or lower.

[0177] By running the glass cloth in a liquid irradiated with ultrasonic waves using an ultrasonic oscillator, the glass cloth can be cleaned by irradiating it with ultrasonic waves in the liquid. The thread tension acting on the warp yarns during the cleaning process is preferably 30N to 500N / 1m.

[0178] Ultrasonic cleaning can be performed using ultrasonic waves with a frequency of 20 kHz or higher and 200 kHz or lower. The preferred frequency is 20 kHz or higher and 50 kHz or lower, more preferably 20 kHz or higher and 30 kHz or lower. Using ultrasonic waves with a frequency of 20 kHz or higher and 200 kHz or lower avoids significant defects such as mesh bending in the glass cloth, thus enabling cleaning and is therefore preferred.

[0179] Ultrasonic cleaning is preferably performed using an output power of 0.07 W / cm². 2 Above and 3.60W / cm 2 The following ultrasound. A more preferred range for ultrasound output power is 0.14 W / cm. 2 Above and 2.16W / cm 2 The preferred range is 0.21 W / cm². 2 Above and 1.44W / cm 2 The ultrasonic output power is 0.07W / cm. 2 At the above levels, it can perform cleaning effectively, with an ultrasonic output power of 3.60 W / cm². 2 The following process does not result in mesh bending or other issues, allowing for even cleaning, and is therefore preferred.

[0180] The transport speed of the glass cloth during ultrasonic cleaning is preferably 50 m / min or less, more preferably 40 m / min or less, and particularly preferably 30 m / min or less. If the transport speed of the glass cloth is 50 m / min or less, the glass cloth or its intermediate components can be cleaned / opened effectively, and the number of warp bundle segments and the warp bonding ratio can be more easily controlled within the specified range. Furthermore, it can suppress fuzzing and mesh shift caused by damage during transport, and is therefore preferred.

[0181] The liquid used in ultrasonic cleaning typically contains dissolved air, primarily composed of nitrogen and oxygen. The dissolved oxygen content (by weight) is preferably 1 ppm to 20 ppm, more preferably 3 ppm to 17 ppm, and even more preferably 4 ppm to 14 ppm. By managing the dissolved oxygen content, the amount of dissolved gas can be indirectly controlled, thereby controlling the degree of ultrasonic attenuation due to the dissolved gas. A dissolved oxygen content of 1 ppm or higher results in uniform fiber opening, which is preferred. A dissolved oxygen content of 20 ppm or lower provides good cleaning action on fibrous fabrics, which is also preferred. A dissolved oxygen content in the range of 1 ppm to 20 ppm results in uniform and good fiber opening, which is also preferred.

[0182] [Surface treatment process for glass cloth]

[0183] The method for manufacturing glass cloth according to this application may further include a step of surface-treating the glass cloth using a surface treatment agent. The step of adhering the surface treatment agent may include at least one of the following steps: a covering step of adhering the surface treatment agent to the glass surface; and a fixing step of fixing the surface treatment agent to the glass surface by heating and drying. Thus, it is easy to suitably surface treat the glass.

[0184] Methods for causing the surface treatment agent to adhere include: applying a treatment solution containing the surface treatment agent to a glass cloth, or immersing the glass cloth in the treatment solution. As a method of applying the treatment solution to glass through a coating process, it can be: (a) immersing the glass in or passing it through a treatment solution contained in a bath (hereinafter referred to as the "immersion method"); (b) applying the treatment solution to the glass using a roller coater, die coater, or gravure coater, etc. When using the immersion method, it is preferable to select an immersion time of 0.5 seconds or more and 1 minute or less in the treatment solution. Furthermore, when using the immersion method, the glass can be passed through the treatment solution while a specified tension (e.g., 100–250 N) is applied, at a transport speed of 10–50 m / min. Additionally, after coating the glass with the treatment solution, the solvent contained in the treatment solution can be heated and dried using methods such as hot air or electromagnetic waves.

[0185] The concentration of the surface treatment agent contained in the treatment solution is preferably 0.1 to 1.0% by mass, more preferably 0.1 to 0.8% by mass, and even more preferably 0.1 to 0.5% by mass. Accordingly, it is easier and more suitable to perform surface treatment on glass.

[0186] In the fixed process, in order to fully allow the surface treatment agent, such as a silane coupling agent, to react with the glass, the heating and drying temperature is preferably 80°C or higher, more preferably 90°C or higher. Furthermore, in order to prevent the deterioration of the organic groups present in the surface treatment agent, such as the silane coupling agent, the heating and drying temperature is preferably 300°C or lower, and more preferably 180°C or lower.

[0187] [The fiber opening process after surface treatment]

[0188] As a process for opening glass filaments bonded by surface treatment agents, methods such as spray water (high-pressure water opening), vibratory cleaners, ultrasonic water, or liquid rolling mills can be used to open the glass cloth. During this opening process, there is a tendency to further widen the yarn width by reducing the tension applied to the glass cloth. It should be noted that, in order to suppress fuzzing of the glass cloth caused by the opening process, it is preferable to implement measures such as low friction with the contact components during glass yarn weaving, and optimization and high adhesion of the surface treatment agent.

[0189] The processes described above do not necessarily need to be performed in separate processes; multiple processes can be combined into one. The composition of the glass cloth usually remains unchanged before and after fiber opening. Furthermore, the manufacturing method of glass cloth may include optional processes in addition to those described above. For example, a slit-forming process may be performed after the fiber opening process. Additionally, the order of the above processes can be substituted if possible.

[0190] The glass cloth manufacturing method described above allows for increasing the diameter of the filaments to suppress fuzzing, and enables the adjustment of the number of warp bundle segments and the warp bonding ratio to a specified range, thereby improving resin impregnation. The glass cloth of this application can be used, for example, as a material in the manufacture of printed circuit boards.

[0191] Prepreg

[0192] The prepreg of this application contains the aforementioned glass cloth and a matrix resin impregnated into the aforementioned glass cloth. Therefore, a prepreg with fewer pores can be provided.

[0193] Thermosetting resins or thermoplastic resins can be used as the base resin. If possible, a combination of both can be used, and other resins may also be included.

[0194] Examples of thermosetting resins include:

[0195] (a) An epoxy resin formed by reacting a compound having an epoxy group with a compound having at least one group selected from the group consisting of an amino group, a phenolic group, an anhydride group, an acylhydrazine group, an isocyanate group, a cyanate group and a hydroxyl group that react with the epoxy group, and then curing the compound.

[0196] (b) A free radical polymeric cured resin formed by curing a compound having at least one group selected from the group consisting of allyl, methylallyl and acryloyl groups;

[0197] (c) Maleimide triazine resin formed by reacting a compound having a cyanate ester group with a compound having a maleimide group and then curing the mixture.

[0198] (d) A thermosetting polyimide resin formed by reacting maleimide compounds with amine compounds and then curing them;

[0199] (e) Benzoxazine resins, etc., which are formed by cross-linking and curing compounds with benzoxazine rings through heating polymerization.

[0200] It should be noted that, in obtaining (a) the epoxy resin, the compound can react under catalyst-free conditions. Alternatively, catalysts with reaction catalytic capabilities, such as imidazole compounds, tertiary amine compounds, urea compounds, and phosphorus compounds, can be added to induce the reaction. Furthermore, in obtaining (b) the free radical polymerization type curing resin, thermally decomposable catalysts or photodecomposable catalysts can be used as reaction initiators.

[0201] Examples of thermoplastic resins include polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, aromatic polyamide, polyetheretherketone, thermoplastic polyimide, insoluble polyimide, polyamide-imide, and fluoropolymers. For use as an insulating material in printed circuit boards for high-speed communication, polyphenylene ether or modified polyphenylene ether with high free radical reactivity is preferred.

[0202] When the matrix resin used in printed circuit boards for high-speed communication has vinyl or methacryloyl groups, silane coupling agents with high hydrophobicity and functional groups such as methacryloyl groups that participate in free radical reactions have good compatibility with the matrix resin.

[0203] As mentioned above, thermosetting resins and thermoplastic resins can be used in combination. Additionally, the prepreg may also 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, short glass fibers, aluminum borate, and silicon carbide. Inorganic fillers can be used alone or in combination of two or more.

[0204] Printed Circuit Boards

[0205] The printed circuit board of this application contains one or more of the aforementioned prepregs. That is, the printed circuit board has the aforementioned glass cloth and a cured product of a matrix resin composition impregnated into the aforementioned glass cloth. The printed circuit board exhibits high resin adhesion and excellent dielectric properties.

[0206] Integrated Circuits and Electronic Devices

[0207] According to this application, integrated circuits and electronic devices incorporating the aforementioned printed circuit boards are also provided. The integrated circuits and electronic devices obtained using the printed circuit boards of this application exhibit excellent characteristics.

[0208] Example

[0209] The embodiments and comparative examples of this application are described, but this application is not limited to the following embodiments and comparative examples.

[0210] Measurement and Evaluation Methods

[0211] [Physical properties of glass yarn and glass cloth]

[0212] The physical properties of glass yarn and glass cloth, specifically, the number of filaments, the weave density of warp and weft yarns (weave density), the thickness of glass cloth, and the loss on ignition of glass cloth, were determined according to JIS R3420.

[0213] [Average filament diameter of glass yarn]

[0214] For the cross-section of 30 strands of glass yarn at any position, a scanning electron microscope is used to observe and calculate the average value to determine the average filament diameter.

[0215] [Average number of filaments in glass yarn]

[0216] Calculate the average number of filaments measured according to JIS R3420 to obtain the average number of filaments.

[0217] [Warp and weft yarn width]

[0218] A camera with a field of view of approximately 2.3 × 1.7 mm and a resolution of 2.26 μm / pixel is used to scan the glass cloth at 1 mm intervals along either the MD or TD direction. The average width of the warp and weft yarns of the glass cloth is then calculated. The average width of each yarn is calculated using the widths obtained from at least 100 glass yarns.

[0219] [Calculation of warp bonding ratio]

[0220] Glass cloth was embedded in epoxy resin (EPOMOUNT (trade name), curing agent II, manufactured by REFINETEC) and the epoxy resin was cured. The cross-section of the glass cloth, including the resin, was cut and ground to a roundness of 0.9 or higher for the glass filaments. The cross-section was then observed at 2000x magnification using a Hitachi High-Tech SU3500 scanning electron microscope. Each warp yarn was divided into three equal parts, and a total of five cross-sectional images were taken. The total number of filaments and the number of bonding points where the cross-sections were in contact with each other for more than 50 nm were then visually counted in each image. The warp bonding ratio was calculated using the following formula.

[0221] Warp bonding ratio = Number of bonding points of warp filaments bonded to each other ÷ Number of warp filaments

[0222] Perform the same operation on the 15 pieces obtained, and set the average value as the warp bonding ratio.

[0223] [Evaluation methods for fuzzing]

[0224] For glass cloth, a roller-to-roll inspection table is used, with a tension of 100N / 1000mm applied, while halogen lamps are irradiated and the tension is visually determined per 1m. 2 The number of protrusions larger than 1 mm is used to evaluate fuzzing according to the following criteria.

[0225] A: The number of frayed fibers is less than 10.

[0226] B: The number of puffs is 11 or more but less than 30.

[0227] C: The number of puffs is 31 or more but less than 60.

[0228] D: 61 or more threads

[0229] [Methods for determining / evaluating resin impregnation]

[0230] Samples of glass cloth with dimensions of 50mm x 50mm or larger were taken. The sampling was conducted in a manner that prevented the measurement area from bending or touching the sample. The static viscosity of the sampled glass cloth at a liquid temperature of 24°C was measured to be 560 mPa·s × g / cm³. 3The number of voids during impregnation in the matrix resin was used for evaluation. A high-precision camera (frame size: 5120×5120 pixels) was set up perpendicular to the glass cloth, and LED lights (CCS Powerflush Bar type) were used as the light source to illuminate the glass cloth from both sides at a horizontal position 15cm away, with the glass cloth clamped in place. Furthermore, at a field of view of 32mm×32mm, the number of voids larger than 160μm existing between the glass filaments was counted, and the average of three measurements was taken as the void count. Voids represent the portion that has not impregnated into the matrix resin. Therefore, a lower number of voids in the glass cloth indicates excellent impregnation in the matrix resin.

[0231] The resin impregnation performance was evaluated according to the following criteria. It should be noted that the time from immersing the glass cloth test piece in the impregnation varnish until the number of unimpregnated areas was counted was defined as 3 minutes.

[0232] A: The number of un-impregnated areas is less than 80.

[0233] B: The number of unimpregnated areas is more than 81 and less than 160.

[0234] C: The number of unimpregnated areas is more than 161 but less than 200

[0235] D: The number of unimpregnated areas is more than 201 and less than 250.

[0236] E: The number of unimpregnated areas is 251 or more.

[0237] [Method for manufacturing laminated boards]

[0238] For the glass cloth obtained in the examples and comparative examples, 45 parts by weight of polyphenylene ether (manufactured by SABIC, Noryl (trade name) SA9000), 10 parts by weight of triallyl isocyanurate, 45 parts by weight of toluene, and 0.6 parts by weight of 1,3-di(tert-butylisopropylbenzene) were added to a stainless steel container and stirred at room temperature for 1 hour to prepare a varnish. After impregnating the glass cloth with the prepared varnish, it was dried at 115°C for 1 minute to obtain a prepreg. Eight sheets of the obtained prepreg were overlapped, and then copper foil with a thickness of 12 μm was overlapped on both sides and dried at 200°C and 40 kg / cm². 2 Heating and pressurizing for 120 minutes yields a laminated plate.

[0239] [Evaluation method for the heat resistance of laminated boards]

[0240] After removing the copper foil from the laminate obtained through the above operation via etching, it is heated and hydrated at 133°C for 70 hours using a pressure cooker. Then, the hydrated laminate is immersed in a solder bath at 288°C for 20 seconds, and visual inspection is performed to check for any 0.03cm peeling caused by the interface between the glass cloth and the resin. 2 The above expansion (bulging) was observed. Six tests were conducted using each laminate. The evaluation of heat resistance is shown below. It should be noted that the less expansion the laminate exhibits, the better its heat resistance.

[0241] A: In the 6 laminates, none of the laminates expanded.

[0242] B: One laminated plate is in a state of expansion.

[0243] C: Expansion exists between the two laminated plates.

[0244] D: Expansion exists in the three laminated plates.

[0245] E: Expansion exists in 4 to 6 laminated sheets.

[0246] Manufacturing Examples

[0247] [Example 1]

[0248] The warp yarns are prepared using silica glass yarn with a SiO2 content greater than 99.9% by mass, an average filament diameter of 7.5 μm, 50 filaments, and a twist rate of 1.0 Z. At this time, the warp yarns are prepared at a twist rate of 3.0 kg / cm². 2 The load is applied by pressing the warp yarns, which are straightened at a transport speed of 60 m / min, to flatten the glass yarn. Then, a sizing agent with polyvinyl alcohol (PVA) resin as the main component is applied according to the following steps: A 5% aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) is prepared, and 2% hydrogenated castor oil as a lubricant is mixed into this aqueous solution to obtain the sizing agent. The sizing agent, which has been kept at 60°C, is applied to the glass yarn and then dried, thus performing the sizing treatment. Subsequently, the glass cloth fabric is woven using an air-jet loom with a warp density of 66 ends / inch and a weft density of 68 ends / inch. It should be noted that the weaving is done with a fabric width of 1300 mm. As the weft yarn, silica glass yarn with an average filament diameter of 7.5 μm, a filament count of 50, and a twist of 1.0 Z is used.

[0249] The obtained glass cloth blank is transported at a linear speed while being immersed in a water tank containing ion-exchange water at 60°C for 15 seconds, and the sizing agent adhering to the glass surface is cleaned (cleaning process before degreasing). Then, in a heating furnace set up on the same production line, the glass cloth blank is heated at 1000°C for 30 seconds using a roller-to-roll method to degrease it, obtaining glass cloth (heating degreasing process). Next, the glass cloth is run in water with a transport tension of 200N and a linear speed of 30m / min, while being irradiated with a frequency of 25GHz and an output power of 0.72W / cm². 2 Ultrasonic cleaning was used to remove residue (cleaning and fiber opening process). Next, a treatment solution was prepared by dispersing 0.3% by mass of 3-methacryloyloxypropyltrimethoxysilane and Z6030 (Toray Down) in pure water adjusted to pH 3 with acetic acid. The fabric was immersed in the treatment solution and squeezed out, then heated and dried at 130°C for 60 seconds to fix the silane coupling agent. The solution was then sprayed at 3.0 kg / cm². 2 High-pressure fiber opening (a fiber opening process after surface treatment) is applied to the dried fabric, followed by drying at 130°C for 1 minute to obtain glass cloth. The thickness, warp width, weft width, (warp bundle segment number - 0.2) / T value, warp bonding ratio, 24×DT value, 14×DT value, and loss on ignition of the obtained glass cloth are measured. Additionally, napping and resin impregnation are evaluated. Furthermore, laminates are fabricated using the above method, and their heat resistance is evaluated.

[0250] [Example 2]

[0251] The warp yarns are prepared using silica glass yarn with a SiO2 content greater than 99.9% by mass, an average filament diameter of 9.0 μm, a filament count of 34, and a twist rate of 1.0 Z. At this time, the warp yarns are prepared at a twist rate of 3.0 kg / cm². 2The load is applied by pressing the warp yarns, which are straightened at a transport speed of 60 m / min, to flatten the glass yarn. Then, a sizing agent with polyvinyl alcohol (PVA) resin as the main component is applied according to the following steps: A 5% aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) is prepared, and 2% hydrogenated castor oil as a lubricant is mixed into this aqueous solution to obtain the sizing agent. The sizing agent, which has been kept at 60°C, is applied to the glass yarn and then dried, thus performing the sizing treatment. Subsequently, the fabric is woven using an air-jet loom with a warp density of 66 ends / inch and a weft density of 68 ends / inch. It should be noted that the fabric is woven with a width of 1300 mm. The weft yarn is made of silica glass with an average filament diameter of 9.0 μm, a filament count of 34, and a twist of 1.0 Z. Using the obtained glass cloth blank, the conditions were changed to those listed in the table. Otherwise, the glass cloth of Example 2 was obtained using the same method as in Example 1.

[0252] [Example 3]

[0253] The warp yarns are prepared using silica glass yarn with a SiO2 content greater than 99.9% by mass, an average filament diameter of 7.5 μm, a filament count of 96, and a twist rate of 1.0 Z. At this time, the warp yarns are prepared at a twist rate of 3.5 kg / cm². 2 The load is applied by pressing the warp yarns, which are straightened at a transport speed of 60 m / min, to flatten the glass yarn. Then, a sizing agent with polyvinyl alcohol (PVA) resin as the main component is applied according to the following steps: A 5% aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) is prepared, and 2% hydrogenated castor oil as a lubricant is mixed into this aqueous solution to obtain the sizing agent. The sizing agent, which has been kept at 60°C, is applied to the glass yarn and then dried, thus performing the sizing treatment. Subsequently, the fabric is woven using an air-jet loom with a warp density of 54 ends / inch and a weft density of 54 ends / inch. It should be noted that the fabric is woven with a width of 1300 mm. As the weft yarn, silica glass yarn with an average filament diameter of 7.5 μm, a filament count of 96, and a twist of 1.0 Z is used. Using the obtained glass cloth blank, the tension of the cleaning and fiber opening process was set to 250N, and the conditions were changed to those recorded in the table. Otherwise, the glass cloth of Example 3 was obtained using the same method as in Example 1.

[0254] [Example 4]

[0255] The warp yarns are prepared using silica glass yarn with a SiO2 content greater than 99.9% by mass, an average filament diameter of 6.0 μm, a filament count of 22, and a twist rate of 0.6 Z. At this time, the warp yarns are prepared at a twist rate of 3.0 kg / cm². 2The load is applied by pressing the warp yarns, which are straightened at a transport speed of 60 m / min, to flatten the glass yarn. Then, a sizing agent with polyvinyl alcohol (PVA) resin as the main component is applied according to the following steps: A 5% aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) is prepared, and 2% hydrogenated castor oil as a lubricant is mixed into this aqueous solution to obtain the sizing agent. The sizing agent, which has been kept at 60°C, is applied to the glass yarn and then dried, thus performing the sizing treatment. Subsequently, the fabric is woven using an air-jet loom with a warp density of 95 ends / inch and a weft density of 95 ends / inch. It should be noted that the fabric is woven with a width of 1300 mm. As the weft yarn, silica glass yarn with an average filament diameter of 6.0 μm, a filament count of 22, and a twist of 0.6 Z is used. Using the obtained glass cloth blank, the conditions were changed to those listed in the table. Otherwise, the glass cloth of Example 4 was obtained using the same method as in Example 1.

[0256] [Comparative Example 1]

[0257] The warp yarns are prepared using silica glass yarn with a SiO2 content greater than 99.9% by mass, an average filament diameter of 5.0 μm, 100 filaments, and a twist rate of 1.0 Z. At this time, the warp yarns are prepared at a twist rate of 3.0 kg / cm². 2 The load is applied by pressing the warp yarns, which are straightened at a transport speed of 60 m / min, to flatten the glass yarn. Then, a sizing agent with polyvinyl alcohol (PVA) resin as the main component is applied according to the following steps: A 5% aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) is prepared, and 2% hydrogenated castor oil as a lubricant is mixed into this aqueous solution to obtain the sizing agent. The sizing agent, which has been kept at 60°C, is applied to the glass yarn and then dried, thus performing the sizing treatment. Subsequently, the fabric is woven using an air-jet loom with a warp density of 66 ends / inch and a weft density of 68 ends / inch. It should be noted that the fabric is woven with a width of 1300 mm. As the weft yarn, silica glass yarn with an average filament diameter of 5.0 μm, a filament count of 100, and a twist of 1.0 Z is used. Using the obtained glass cloth blank, the glass cloth of Comparative Example 1 was obtained by the same method as in Example 1.

[0258] [Comparative Example 2]

[0259] Using the glass cloth blank obtained in Comparative Example 1, and changing the conditions as described in the table, except that the glass cloth of Comparative Example 2 was obtained using the same method as in Example 1.

[0260] [Comparative Example 3]

[0261] The warp yarns are prepared using silica glass yarn with a SiO2 content greater than 99.9% by mass, an average filament diameter of 5.0 μm, 200 filaments, and a twist rate of 1.0 Z. At this time, the warp yarns are prepared at a twist rate of 3.5 kg / cm². 2 The load is applied by pressing the warp yarns, which are straightened at a transport speed of 60 m / min, to flatten the glass yarn. Then, a sizing agent with polyvinyl alcohol (PVA) resin as the main component is applied according to the following steps: A 5% aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) is prepared, and 2% hydrogenated castor oil as a lubricant is mixed into this aqueous solution to obtain the sizing agent. The sizing agent, which has been kept at 60°C, is applied to the glass yarn and then dried, thus performing the sizing treatment. Subsequently, the fabric is woven using an air-jet loom with a warp density of 54 ends / inch and a weft density of 54 ends / inch. It should be noted that the fabric is woven with a width of 1300 mm. As the weft yarn, silica glass yarn with an average filament diameter of 5.0 μm, a filament count of 200, and a twist of 1.0 Z is used. Using the obtained glass cloth blank, the glass cloth of Comparative Example 3 was obtained by using the same method as in Example 3.

[0262] [Comparative Example 4]

[0263] The warp yarns are prepared using silica glass yarn with a SiO2 content greater than 99.9% by mass, an average filament diameter of 4.0 μm, 50 filaments, and a twist rate of 0.6 Z. At this time, the warp yarns are prepared at a twist rate of 3.0 kg / cm². 2 The load is applied by pressing the warp yarns, which are straightened at a transport speed of 60 m / min, to flatten the glass yarn. Then, a sizing agent with polyvinyl alcohol (PVA) resin as the main component is applied according to the following steps: A 5% aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) is prepared, and 2% hydrogenated castor oil as a lubricant is mixed into this aqueous solution to obtain the sizing agent. The sizing agent, which has been kept at 60°C, is applied to the glass yarn and then dried, thus performing the sizing treatment. Subsequently, the fabric is woven using an air-jet loom with a warp density of 95 ends / inch and a weft density of 95 ends / inch. It should be noted that the fabric is woven with a width of 1300 mm. As the weft yarn, silica glass yarn with an average filament diameter of 4.0 μm, a filament count of 50, and a twist of 0.6 Z is used. Using the obtained glass cloth blank, the glass cloth of Comparative Example 4 was obtained by using the same method as in Example 4.

[0264] [Example 5]

[0265] Using the glass cloth blank obtained in Example 1, without irradiating it with ultrasound before surface treatment, and changing the conditions to those described in the table, the glass cloth of Example 5 was obtained using the same method as in Example 1.

[0266] [Example 6]

[0267] Using the glass cloth blank obtained in Example 1, the linear speed was set to 80 m / min, and the glass cloth of Example 6 was obtained by the same method as in Example 1.

[0268] [Comparative Example 5]

[0269] The warp yarns are prepared using silica glass yarn with a SiO2 content greater than 99.9% by mass, an average filament diameter of 6.0 μm, a filament count of 22, and a twist of 0.6 Z. At this stage, the warp yarns, aligned at a transport speed of 60 m / min, are not pressed. A sizing agent with polyvinyl alcohol (PVA) resin as the main component is applied according to the following steps: A 5% aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) is prepared, and 2% hydrogenated castor oil as a lubricant is mixed into this aqueous solution to obtain the sizing agent. The sizing agent, which has been kept at 60°C, is applied to the glass yarn and then dried, thus performing the sizing treatment. Subsequently, the fabric is woven using an air-jet loom with a warp density of 95 ends / inch and a weft density of 95 ends / inch. It should be noted that the fabric is woven with a width of 1300 mm. As the weft yarn, silica glass yarn with an average filament diameter of 6.0 μm, a filament count of 22, and a twist count of 0.6 Z was used. Using the obtained glass cloth prefabricated fabric, the conditions described in the table were changed, except that the glass cloth of Comparative Example 5 was obtained using the same method as in Example 4.

[0270] [Comparative Example 6]

[0271] Using the glass cloth blank obtained in Example 4, ion-exchange water at 20°C was used in the pre-degreasing cleaning process. Otherwise, the glass cloth of Comparative Example 6 was obtained using the same method as in Example 4.

[0272] [Table 1]

[0273]

[0274] [Table 2]

[0275]

[0276] In Examples 1-7, where glass cloths with a filament diameter thicker than the thickness of the glass cloth were used, and the yarn bundles were flattened during warping before sizing, and the glass cloths were washed with water at a specified temperature or higher before being heated to remove oil, the number of warp yarn bundle segments was within a specified range, and fuzzing was suppressed. Furthermore, in Examples 1-4, where glass cloths were cleaned ultrasonically at a specified transport speed before the surface treatment process, the number of warp yarn bundle segments and the warp bonding ratio were within a specified range, resulting in good resin impregnation and heat resistance of the laminate.

[0277] In Comparative Examples 1-4, the glass cloths manufactured according to the filament diameter specified in the IPC standard had a larger number of warp bundle segments, making it impossible to suppress fuzzing. Furthermore, the resin penetration was poor. In Comparative Example 2, increasing the processing force during the fiber opening treatment resulted in increased fuzzing.

[0278] In addition, in Comparative Example 5, where the yarn bundles were not flattened during warping, and in Comparative Example 6, where the glass cloth was not washed with water at a specified temperature or above before being heated to remove oil, the number of warp bundle segments and the warp bonding ratio could not be controlled within the specified range, resulting in more fuzzing and poor resin penetration.

Claims

1. A type of glass cloth, comprising glass yarn containing multiple filaments as warp and weft yarns. The silicon (Si) content of the glass yarn, calculated based on silicon dioxide (SiO2), is 95.0% to 100% by mass. The thickness (T) of the glass cloth is less than 80 μm and satisfies the following formula (A1): {Number of warp bundle segments (N) - 0.2} / Thickness (T) [μm] < 0.056 … (A1) In formula (A1), the number of warp bundle segments (N) is a value obtained by multiplying the warp filament diameter [μm] by the number of warp filaments [strands] ÷ the warp width [μm]. When the thickness of the glass cloth is 20 μm or more and 80 μm or less, the following formula (B1) is satisfied; when the thickness of the glass cloth is less than 20 μm, the following formula (B6) is satisfied. 24 × average filament diameter (D) [μm] - thickness (T) [μm] > 96 … (B1) 14 × average filament diameter (D) [μm] - thickness (T) [μm] > 46 … (B6).

2. The glass cloth according to claim 1, wherein, After the glass cloth is embedded in epoxy resin and the epoxy resin is cured, when the cross-section of the glass cloth is observed, the warp bonding ratio calculated by the following formula is greater than 0 and less than 0.

80. Warp bonding ratio = number of bonding points of the warp filaments bonded to each other ÷ number of warp filaments.

3. The glass cloth according to claim 1, wherein it is treated with a surface treatment agent containing a silane coupling agent.

4. The glass cloth according to claim 3, wherein, The silane coupling agent comprises a compound represented by the following formula (C). X(R) 3-n SiY n …(C) In formula (C), X is an organic group having at least one of an amino group and an unsaturated double bond group with free radical reactivity, Y is an alkoxy group, n is an integer of 1 to 3, and R is a group selected from the group consisting of methyl, ethyl, and phenyl.

5. The glass cloth according to claim 4, wherein, In the formula (C), X is an organic group having one or more methacryloyloxy or acryloyloxy groups.

6. The glass cloth according to any one of claims 1 to 5, wherein, The average filament diameter (D) of the glass yarn is above 4 μm.

7. The glass cloth according to any one of claims 1 to 5, wherein, The thickness (T) of the glass cloth is less than 60 μm.

8. The glass cloth according to any one of claims 1 to 5, wherein, The loss on ignition of the glass cloth is in the range of 0.01% to 0.30% by mass.

9. The glass cloth according to any one of claims 1 to 5, used for printed circuit boards.

10. A prepreg comprising the glass cloth, thermosetting resin, and inorganic filler as described in any one of claims 1 to 5.

11. A printed circuit board comprising the prepreg of claim 10.

12. An integrated circuit comprising the printed circuit board of claim 11.

13. An electronic device comprising the printed circuit board of claim 11.

14. A method for manufacturing glass cloth, wherein, The method includes: The process of weaving glass yarn, which contains multiple long filaments and has a Si content (calculated as SiO2) ranging from 95.0% to 100% by mass, as both warp and weft yarns, to obtain glass cloth. The method further includes: Before the weaving process, the glass yarn bundles are flattened, followed by a sizing and warping process. The following processes are included after the warping process and before, during, or after the weaving process: The process of cleaning glass fiber with water at a temperature above 50°C; The process of heating and degreasing the cleaned glass yarn; and In a liquid irradiated with ultrasound, the glass yarn edge, which has been heated and degreased, is transported at a speed of less than 50 m / min while being cleaned and split. The thickness (T) of the glass cloth after the fiber opening treatment is less than 80 μm. When the thickness of the glass cloth after the fiber splitting treatment is 20 μm or more and 80 μm or less, the following formula (B1) is satisfied; when the thickness of the glass cloth after the fiber splitting treatment is less than 20 μm, the following formula (B6) is satisfied. 24 × average filament diameter (D) [μm] - thickness (T) [μm] > 96 … (B1) 14 × average filament diameter (D) [μm] - thickness (T) [μm] > 46 … (B6).

15. The method of claim 14, further comprising: The process of surface treating the glass cloth after cleaning and fiber opening using a surface treatment agent.

Images