Glass cloth, prepreg, and printed wiring board

Abstract

A glass cloth, a prepreg, and a printed wiring board. The object of the present invention is to provide a glass cloth having a thickness of 20 μm or less and having a low risk of breakage. A glass cloth is provided, which includes a specific region having an elongation of 1.4% or more and 4.0% or less until reaching a breaking point when a tensile stress is applied in the warp direction in both end regions in the width direction.

Description

TECHNICAL FIELD

[0001] The present application relates to glass cloth, prepreg, and printed wiring board. BACKGROUND

[0002] In recent years, as the information communication society has developed, data communication and / or signal processing is performed at high speed and with large capacity, and low dielectric constant of printed wiring boards used in communication equipment or measuring instruments such as high-end servers or high-end routers / switches, supercomputers, base stations, and the like has been significantly performed. Therefore, many low-dielectric glass cloths have been proposed for the glass cloth constituting the printed wiring board.

[0003] For example, the low-dielectric glass cloth disclosed in Patent Literature 1 realizes a low dielectric constant by blending a large amount of B2O3 in the glass composition of the E glass cloth that has been used until now, while adjusting the blending amount of other components such as SiO2.

[0004] In addition, for terminal electronic equipment such as smartphones, high-speed / high-capacity communication is also required, and low dielectric constant of printed wiring boards used in smartphone main board substrates or semiconductor substrates has also recently begun to rapidly expand. Therefore, there is a strong demand for extremely thin low-dielectric glass cloths having a thickness of 10 μm to 20 μm.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 2010-508226 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, if the thickness of the glass cloth is thinned to 10 μm or more and 20 μm or less, the strength of the glass yarn used is necessarily weakened due to a decrease in the number of filaments. Therefore, the thin low-dielectric glass cloth has a problem in that the risk of breakage increases due to the superposition of the strength reduction due to low dielectric and the strength reduction due to thinning.

[0010] In the case where a prepreg is manufactured using such a glass cloth, there is a problem in that the glass cloth breaks and production problems occur in a scenario where an operation to control the resin adhesion amount or the like applies an external load to the glass cloth.

[0011] The present application has been made in view of the above problems, and an object thereof is to provide a glass cloth having a thickness of 20 μm or less and having a small risk of breakage.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] The present inventors etc. investigated in detail the cause of breakage of a glass cloth having a thickness of 20 μm or less during conveyance on a production line in order to solve the above problem, and as a result, it was found that breakage of the glass cloth mostly occurs on the width direction end side, and unexpectedly, the elongation until breakage when stress is applied in the warp direction is specifically reduced on the width direction end side. Thus, a method for increasing the elongation in the warp direction of the glass cloth end was explored, and it was found that the above problem can be solved by setting the elongation in the warp direction of the glass cloth end to a certain value or more, thereby completing the present invention. One mode of the present invention is described below. [1]

[0015] A glass cloth including a specific region having an elongation of 1.4% or more and 4.0% or less until breakage when tensile stress is applied in the warp direction in both end regions in the width direction. [2]

[0017] The glass cloth according to item 1, wherein the width direction length of the glass cloth is 1000 mm or more and 1500 mm or less, and the thickness is 5 μm or more and 20 μm or less. [3]

[0019] The glass cloth according to item 1 or 2, wherein the elongation until breakage when the tensile stress is applied in the warp direction in both end regions in the width direction is 1.7% or more in both end regions. [4]

[0021] The glass cloth according to any one of items 1 to 3, wherein the elongation until breakage when the tensile stress is applied in the warp direction in the width direction central region is 0.1% or more greater than the elongation until breakage when the tensile stress is applied in the warp direction in both end regions in the width direction. [5]

[0023] The glass cloth according to any one of items 1 to 4, wherein at least a part of the specific region exists at a symmetrical position sandwiching the MD center line in both end regions in the width direction. [6]

[0025] The glass cloth according to any one of items 1 to 5, wherein the breaking strength when the tensile stress is applied in the warp direction in both end regions in the width direction is 30 N / 25 mm or more. [7]

[0027] The glass cloth according to any one of items 1 to 6, wherein the breaking strength when the tensile stress is applied in the warp direction in both end regions in the width direction in a state of being wetted with water is 30 N / 25 mm or more. [8]

[0029] The glass cloth according to any one of items 1 to 7, wherein the average diameter of the single filaments constituting the glass filaments of the glass cloth is 5 μm or less, and the number of the single filaments is 30 to 70. [9]

[0031] The glass cloth according to any one of items 1 to 8, wherein the elastic modulus thereof is more than 0 and 70 GPa or less.

[10]

[0033] A rolled glass cloth which is rolled up the glass cloth according to any one of items 1 to 9.

[11]

[0035] The rolled glass cloth according to item 10, wherein at least a part of the specific region is present at a position close to the innermost periphery between the outermost periphery and the innermost periphery of the roll.

[12]

[0037] A prepreg having the glass cloth according to any one of items 1 to 9, and a matrix resin impregnated in the glass cloth.

[13]

[0039] A printed wiring board having the prepreg according to item 12.

[0040] Effects of the Invention

[0041] According to the present invention, it is possible to provide a glass cloth having a thickness of 10 μm to 20 μm which is extremely small in risk of breakage at the time of production of the glass cloth, or at the time of processing of a composite material such as a prepreg using the glass cloth, and which is suitable for stable production. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a schematic top view of the glass cloth of the present embodiment, and also shows collection of test pieces for applying tensile stress.

[0043] Figure 2 is a schematic view for explaining measurement of elongation amount until breakage is reached when a tensile stress is applied to the warp direction end region in the width direction of the glass cloth.

[0044] Figure 3 is a conceptual view of a load-deformation curve (S-S curve).

[0045] EXPLANATION OF REFERENCE NUMERALS

[0046] 1: Glass cloth

[0047] 2: End region in width direction

[0048] 3: Test piece (elongation specific region)

[0049] TD: width direction

[0050] MD: warp direction (also referred to as flow direction, or longitudinal direction)

[0051] X1: width direction edge of glass cloth

[0052] X2: portion 15 cm from the width direction edge (X1) of the glass cloth toward the center direction in the width direction (TD) DETAILED DESCRIPTION

[0053] Embodiments of the present application (hereinafter referred to as "the present embodiments") will be described in detail below with reference to the accompanying drawings, but the present application is not limited thereto, and various modifications can be made without departing from the gist thereof.

[0054] [Glass Cloth]

[0055] The glass cloth of the present embodiments contains a specific region in which the elongation until reaching the breaking point when a tensile stress is applied in the warp direction is 1.4% or more and 4.0% or less in the regions at both ends in the width direction.

[0056] When the glass cloth is processed, or when a composite material such as a prepreg using the glass cloth is processed, in order to adjust the amount of water or chemical liquid adhering to the glass cloth, a process of stretching and conveying in the MD direction while the glass cloth is gripped by a nip roll, a liquid press roll, or the like is sometimes performed; or a process of stretching and conveying in the MD direction while passing through a slit with an extremely narrow gap is sometimes performed, in which case the glass cloth is stretched and conveyed in the MD direction while being subjected to a large resistance. It was found at this time that the tension applied to the glass cloth differs in the width direction, and that a strong tensile stress is applied in the range from the end portion in the width direction, particularly the most end portion, to within 20 cm from the most end portion.

[0057] Furthermore, it was found that the elongation until reaching the breaking point when a tensile stress is applied to the glass cloth in the conventional glass cloth having a thickness of 10 μm to 20 μm is unexpectedly reduced specifically in the end portion in the width direction.

[0058] From the above two points, the reason for the breaking of the glass cloth, particularly the reason for the breaking of the glass cloth when the glass cloth is processed, is not limited, but it is believed to be the following phenomenon:

[0059] In the process of stretching and conveying the glass cloth while sandwiching the glass cloth in the MD direction, or in the process of stretching and conveying the glass cloth while passing through a slit with a very narrow gap, the glass cloth is subjected to a tension in the warp direction while being subjected to a large resistance. At this time, due to variations in the linear tension, deformation of the sandwiching rollers or deviation of the slit gap, deformation of the glass cloth itself, and the like, the resistance received by the glass cloth, and further the stretching stress applied to the glass cloth, varies. In the situation where the stretching stress varies, when a large stretching stress suddenly occurs in the width direction end region where the stretching stress is most likely to be applied in the width direction, (in the worst case) this region is also the region where the elongation until the breaking point is reached in the width direction is the smallest, and thus the region cannot withstand the stretching stress and breaks.

[0060] In contrast, in the present embodiment, by including the specific region in which the elongation until the breaking point is reached when the stretching stress is applied in the warp direction is adjusted to a value in the range of 1.4% or more and 4.0% or less in both the width direction end regions, the risk of breaking of the glass cloth is significantly reduced regardless of variations in the tension in the conveying of the glass cloth, deformation of the glass cloth itself or variations in the characteristic values, deviations of the sandwiching rollers or the slit gap, and the like, and the processing of the glass cloth, and the processing of the composite material such as a prepreg using the glass cloth, can be stably performed.

[0061] The technical features of the present embodiment will be described in more detail below.

[0062] (Elongation until the breaking point / two end regions)

[0063] In the present embodiment, the elongation until the breaking point when the stretching stress is applied in the warp direction in the width direction end regions is 1.4% or more and 4.0% or less in both the end regions, that is, the specific region described above exists in both the width direction end regions of the glass cloth. The preferred range of the elongation of both the end regions until the breaking point when the stretching stress is applied in the warp direction in both the width direction end regions of the glass cloth is 1.7% or more, more preferably 2.0% or more, and further preferably 2.3% or more. The upper limit of the elongation is 4.0%, preferably 3.7%, and further preferably 3.2%.

[0064] By adjusting the elongation until the breaking point when the stretching stress is applied in the warp direction to be 1.4% or more and 4.0% or less in both the end regions, the risk of breaking of the glass cloth is significantly reduced when the glass cloth is processed, or when a composite material such as a prepreg using the glass cloth is processed.

[0065] The elongation until the breaking point when a tensile stress is applied in the warp direction is large, which is suitable for cloth breaking, but if the glass cloth is used as a reinforcing material for dimensional stability in a printed wiring board, the upper limit value is 4.0%. By the elongation amount being below the upper limit value, the dimensional stability of the glass cloth is excellent, and a practical range of dimensional stability is obtained, and thus is preferred.

[0066] From the same viewpoint as described above, at least a part of the specific region of the glass cloth is preferably present at a symmetrical position sandwiching the MD center line at both width direction end regions.

[0067] (relationship between the region of the glass cloth and the elongation amount)

[0068] Figure 1 is a top view schematic diagram of the glass cloth (1) of the present embodiment, and also shows the collection of test pieces for applying a tensile stress. Figure 2 is a schematic diagram for explaining the measurement of the elongation amount until the breaking point when a tensile stress is applied in the warp direction in the width direction end region (2) of the glass cloth (1).

[0069] Here, the elongation amount of the glass cloth until the breaking point when a tensile stress is applied in the warp direction is a value calculated as described below:

[0070] The elongation amount of the glass cloth when a tensile stress is applied in the warp direction is measured using the method described in the item of JIS R3420, General Test Method for Glass Test, 7.4 Tensile Strength. In the present embodiment, in order to improve the measurement accuracy, the tensile speed is set to about 5 mm / minute, and the width of the collected test piece is set to about 35 mm, and the tensile test is performed under the same conditions as the method prescribed in the above JIS, and the displacement amount at the breaking point of the glass cloth is calculated, and the value calculated using the following formula (1) is defined as the "elongation amount of the glass cloth".

[0071] Elongation amount = {(gap at the breaking point - gap under no load) / gap under no load} x 100 (1)

[0072] More specifically, as shown in Figure 1 a test piece (3) (35 mm x 250 mm) is collected from the glass cloth (1). The size of the collected test piece (3) is as shown in Figure 2 .

[0073] Next, as shown in Figure 2As shown, the filaments of the two end regions of the test piece (3) were untangled, a clamping interval of 25 mm in width and 150 mm + 0 to 1 mm (for example, in the range of 150 mm to 151 mm) was installed in the clamping portion, and the elongation was measured. In the measurement of the elongation, the "confirmation until the breaking" did not require observation until the instant when the glass cloth was actually broken (broken), for example, by real-time measurement of the load-deformation curve (S-S curve) or the like, but confirmation until the time when the slow occurrence of the cut in the filament unit (strictly speaking, the cut in the monofilament unit constituting the filament) was confirmed as the glass cloth was stretched.

[0074] For example, as shown in the conceptual diagram of the load-deformation curve (S-S curve) Figure 3 ), a certain period of time from the start of the measurement, the glass cloth as a whole resisted the tensile stress, and then several filaments started to break, and the S-S curve was considered to "break" when it changed from rising to falling.

[0075] In addition, as shown in Figure 1 , the width direction end region (2) of the glass cloth (1) refers to the region from the width direction edge (X1) along the width direction until the portion (X2) 15 cm from the both ends toward the center. In the case where the CC processing (coating and cutting processing) is performed on the both end portions of the glass cloth, in the measurement of the elongation until the breaking when the tensile stress is applied to the filament direction described above, the place without the CC processing is measured.

[0076] As a method of adjusting the elongation until the breaking when the tensile stress is applied to the filament direction of the both end portions in the width direction to the numerical range described above, the present inventors found that the following methods (1) to (3) are effective.

[0077] (1) A method of forming a fabric structure that is not easily subjected to large shearing on the both end portions before the stage of strengthening the glass cloth by silane coupling agent treatment, by setting the tension of the filaments of the both end portions to be weaker than the central portion in the beaming process in the manufacture of the glass cloth:

[0078] It is presumed that, by the tension of the both end portions being weaker than the central portion in the beaming process, the tension of the filaments of the both end portions is suppressed compared to the central portion, and therefore when the stress due to the thermal expansion of the take-up core tube in the heat treatment process or the stress due to the tensile tension at the time of roll conveyance in the silane coupling agent treatment process acts, the stress acting on the both end portions is suppressed to be lower than the stress acting on the central portion (the filaments stretch fast and the acting stress), and therefore the damage received by the both end portions is reduced, and there is a tendency for the elongation of the both end portions to increase.

[0079] On the contrary, if the tension of the both end portions in the beaming process is stronger than the central portion, there is a tendency for the elongation of the both end portions to decrease.

[0080] (2) In the process of obtaining a glass cloth intermediate in a roll shape for a heat cleaning process in the manufacture of a glass cloth, when the glass cloth intermediate is wound on a core pipe for heat cleaning, the winding is performed while the glass cloth is uncontracted, whereby the heating treatment is uniformly performed in the width direction of the glass cloth:

[0081] It is presumed that, in the winding of the glass cloth, the glass cloth is contracted, and therefore the glass density of the central portion of the glass cloth becomes large, and on the contrary, the glass density of the end portions becomes sparse. Therefore, when the heat history required for the heat cleaning of the entire glass cloth is provided, the end portions are excessively subjected to the heating treatment, are easily damaged due to the heating, and there is a tendency that the elongation of the end portions decreases.

[0082] It is presumed that, by expanding the glass cloth in the width direction while the winding contraction is released, the glass density becomes close to uniform in the width direction, and therefore the damage of the end portions of the glass cloth due to the excessive heating is mitigated, and there is a tendency that the elongation of the end portions increases.

[0083] (3) In the manufacture process of the glass cloth, the roller diameters of the both end portions of the nip roller through which the silane coupling agent liquid passes in order to adjust the adhering amount of the silane coupling agent liquid are smaller than that of the central portion, and a large shear is not easily applied to the both end portions:

[0084] The strength of the glass cloth is decreased due to the heat cleaning. It is presumed that, in the process of coating the glass cloth subjected to the heat cleaning with the silane coupling agent (the stage before the reinforcement by the coating with the silane coupling agent / after the coating of the silane coupling agent and the drying, the completion of the coating), the roller diameters of the both end portions of the roller used in the conveyance during the coating of the silane coupling agent and the drying, which are controlled by the nip roller, are smaller than that of the central portion, the tension applied to the both end portions of the glass cloth is mitigated with respect to the central portion, and therefore the damage of the both end portions is decreased, and there is a tendency that the elongation increases (that is, in the state where the strength is decreased by the heat cleaning and the damage is easily caused, the load applied to the both end portions is decreased).

[0085] On the contrary, it is presumed that, if the concave roller or the like, in which the roller diameter of the both end portions is larger than that of the central portion, is used in order to prevent the wrinkles, a large tension is specifically applied to the both end portions of the glass cloth and the both end portions are damaged, and there is a tendency that the elongation of the both end portions decreases, and therefore attention is required.

[0086] The methods of the above (1) to (3) can be individually implemented, but from the viewpoint of obtaining a greater effect, it is preferable to combine (1) to (3).

[0087] (Elongation until the break / central region)

[0088] In addition, the glass cloth of the present embodiment preferably has an elongation in the width direction central region (a region other than the two end regions in the width direction described above) until breaking when a tensile stress is applied in the warp direction, which is greater than the elongation in the two end regions until breaking when a tensile stress is applied in the warp direction, by 0.1% or more, more preferably 0.15% or more, and further preferably 0.2% or more.

[0089] When the elongation in the width direction central region until breaking when a tensile stress is applied in the warp direction is greater than the elongation in the two end regions until breaking when a tensile stress is applied in the warp direction by 0.1% or more, there is a tendency for the risk of the glass cloth breaking during processing of the glass cloth or during processing of a composite material such as a prepreg using the glass cloth to be significantly reduced.

[0090] The reason is not limited by theory, but it is believed that, during processing of the glass cloth or during processing of a composite material such as a prepreg using the glass cloth, if the glass cloth shrinks when a tension is applied in the MD direction, there is a tendency for the warp yarns in the central portion to be elongated by being released from the curling compared to the warp yarns in the end portions, and thus the elongation until breaking in the width direction central portion is greater than the elongation until breaking in the two end portions, and it is less likely that breaking will occur starting from the central portion of the glass cloth.

[0091] (Breaking strength / two end regions)

[0092] The breaking strength in the two end regions in the width direction in the load-deformation curve in the warp direction of the glass cloth of the present embodiment is preferably 30 N / 25 mm or more. The breaking strength in the two end regions is more preferably 35 N / 25 mm or more, further preferably 40 N / 25 mm or more, and most preferably 50 N / 25 mm or more.

[0093] When the breaking strength in the two end regions in the width direction is 30 N / 25 mm or more, there is a tendency for the risk of the glass cloth breaking during processing of the glass cloth or during processing of a composite material such as a prepreg using the glass cloth to be reduced.

[0094] In addition, the breaking strength in the two end regions in the width direction in the load-deformation curve in the warp direction of the glass cloth of the present embodiment in a state of being wetted with water is preferably 20 N / 25 mm or more. The breaking strength in the two end regions in a state of being wetted with water is more preferably 25 N / 25 mm or more, further preferably 30 N / 25 mm or more, still further preferably 40 N / 25 mm or more, and most preferably 50 N / 25 mm or more.

[0095] Here, the breaking strength in the warp direction is a value calculated as described below.

[0096] The elongation of the glass cloth when tension is applied to the warp direction was measured using the method described in the item of the tensile strength of the general test method for glass test of JIS R3420. In the method prescribed by JIS, a test piece having a width of about 30 mm and a length of about 250 mm was cut from the warp direction of the fabric, the ends of the test piece were untangled to form a width of 25 mm, a clamping interval of 150 mm + 0 to 1 mm (for example, a range of 150 mm to 151 mm) was ensured, and the test piece was installed in the clamping portion. The test piece was stretched at a stretching speed of about 200 mm / min, and the load at the time of breakage was determined. In the present embodiment, the stretching speed was set to 5 mm / min and the width of the test piece was set to about 35 mm in order to improve the measurement accuracy, and the stretching test was performed under the same conditions as the method prescribed by JIS described above until the glass cloth broke. The maximum load value that was tolerated until the glass cloth broke was defined as the "breaking strength".

[0097] The measurement of the breaking strength was performed at the same time as the measurement of the elongation or during the measurement of the elongation, as in the measurement of the elongation described above. As shown in the conceptual diagram of the load-deformation curve (S-S curve) Figure 3 ), the peak position can be regarded as a position corresponding to the "breaking strength".

[0098] In addition, the breaking strength in the state of being wetted with water refers to a value determined as described below. In the measurement of the breaking strength described above, the part of the glass cloth other than the part installed in the clamping portion was immersed in water in advance, and the stretching test was performed as described above until the glass cloth broke. The maximum load value that was tolerated until the glass cloth broke was defined as the "breaking strength in the state of being wetted with water".

[0099] If the breaking strength of the both end regions in the state of being wetted with water is 20 N / 25 mm or more, the risk of breakage of the glass cloth during the processing of the glass cloth or the processing of a composite material such as a prepreg using the glass cloth is reduced.

[0100] The present inventors further studied the relationship between the breakage of the glass cloth and the characteristics of the glass cloth, and as a result, it was found that the behavior of the load-deformation curve is greatly different between the dry state and the wetted state of the glass cloth. In the wetted state of the glass cloth, the yield point is approached at a small elongation compared to the dry state (i.e., the uniform elongation region until the yield point is approached is small), and the load does not increase after the yield point (i.e., the load does not increase in the local elongation region). As a result, it was clarified that the elongation rate until breakage in the wetted state of the glass cloth is the same as in the dry state, but the breaking strength is reduced compared to the dry state.

[0101] Therefore, the inventors have found that the breaking strength of the glass cloth in a wet state can be an index for estimating the risk of breakage of the glass cloth, and that the risk of breakage of the glass cloth is further reduced by setting the breaking strength of the glass cloth in a wet state to 20 N / 25 mm or more.

[0102] As a method for adjusting the breaking strength of the glass cloth in a wet state to 20 N / 25 mm or more, the same method as that for adjusting the elongation of the warp direction in the regions of both ends in the width direction to 1.3% or more, or 1.4% or more and 4.0% or less until reaching the breaking point can be used.

[0103] (Structure of the glass cloth)

[0104] The weaving structure of the glass cloth is not particularly limited, and examples thereof include plain weave, basket weave, satin weave, twill weave, and the like. Among them, the plain weave structure is more preferable.

[0105] The thickness of the glass cloth is preferably 5 μm to 20 μm, more preferably 8 μm to 20 μm, further preferably 9 μm to 20 μm, and particularly preferably 10 μm to 18 μm. By setting the thickness of the glass cloth within the above range, a thin and high-strength glass cloth can be obtained, and thus it is preferable from the viewpoint of forming a thin insulating layer and the viewpoint of improving the processability of the insulating layer by carbon dioxide laser or mechanical drilling.

[0106] The average diameter of the single filaments of the glass filaments constituting the glass cloth is preferably 6 μm or less, and the number of single filaments is preferably 30 to 120 or less. A more preferable range of the average diameter of the single filaments and the number of single filaments is 5.5 μm or less in the average diameter and 30 to 90 in the number of filaments, and a further preferable range is 5 μm or less in the average diameter and 30 to 70 in the number of filaments.

[0107] If the single filament diameter is 6 μm or less and the number of single filaments is 120 or less, there is a tendency to obtain a thin and high-strength glass cloth of 30 μm or less, and thus it is preferable.

[0108] The beating-up density of the warp filaments and the weft filaments constituting the glass cloth is preferably 30 to 120 per inch, more preferably 40 to 110 per inch, and further preferably 50 to 100 per inch.

[0109] The cloth weight (weight per unit area) of the glass cloth is preferably 8 to 250 g / m 2 , more preferably 8 to 100 g / m 2 , further preferably 8 to 50 g / m 2 , and particularly preferably 8 to 35 g / m 2 .

[0110] The elastic modulus of the glass cloth is preferably more than 0 and 70 GPa or less, more preferably 50 GPa or more and 70 GPa or less, further preferably 53 GPa or more and 70 GPa or less, particularly preferably 53 GPa or more and 63 GPa or less.

[0111] By the elastic modulus being more than 0, the strength of the glass cloth is improved, and there is a tendency that the glass cloth does not easily break during processing of the glass cloth or during processing of a composite material such as a prepreg using the glass cloth. In addition, by the elastic modulus being 70 GPa or less, the strength of the glass cloth is reduced, and there is a tendency that the glass cloth easily breaks during processing of the glass cloth or during processing of a composite material such as a prepreg using the glass cloth, but by the present application, the elongation of the width direction end portion until reaching the breaking point is adjusted to the numerical range described above, whereby the risk of breaking is greatly reduced, and thus it is useful.

[0112] From the viewpoint of balancing stable productivity and thinness, the glass cloth of the present embodiment is preferably 1000 mm or more and 1500 mm or less in the width direction length and 5 μm or more and 20 μm or less in thickness.

[0113] From the viewpoint of effectively exerting the effect of the present application, the glass cloth is preferably in a roll shape, and the roll-shaped glass cloth can be formed by winding a glass cloth in a form other than a roll. From the same viewpoint, the elongation as described above is preferably present in at least a part of the specific region in the width direction region of the specific glass cloth, at a position close to the innermost periphery between the outermost periphery and the innermost periphery of the roll of the roll-shaped glass cloth.

[0114] (Surface treatment)

[0115] The glass cloth can be a glass cloth that has been subjected to surface treatment with a surface treatment agent. There is no particular limitation on the surface treatment agent, and examples include silane coupling agents, and water, organic solvents, acids, dyes, pigments, surfactants, and the like can be used together as needed.

[0116] There is no particular limitation on the silane coupling agent, and examples include compounds represented by formula (1).

[0117] X(R) 3-n SiY n (1)

[0118] (In formula (1), X is an organic functional group having at least one or more of an amino group and an unsaturated double bond group, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is each independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group.)

[0119] X is preferably an organic functional group having at least 3 or more of an amino group and an unsaturated double bond group, and X is more preferably an organic functional group having at least 4 or more of an amino group and an unsaturated double bond group.

[0120] As the above alkoxyl group, any one of the forms can be used, but from the viewpoint of stable treatment of the glass cloth, an alkoxyl group having 5 or less carbon atoms is preferred.

[0121] As the silane coupling agent, specifically, N-β-(N-vinylbenzylaminoethyl)-γ- aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-vinylbenzylaminoethyl)- γ-aminopropylmethyldimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl) aminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl) aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltrimethoxysilane, methacryloyloxypropyltrimethoxysilane, acryloyloxypropyltrimethoxysilane, and the like known single silane coupling agents, or a mixture thereof can be listed.

[0122] [Method for manufacturing glass cloth]

[0123] The method for manufacturing the glass cloth of the present embodiment is not particularly limited, and a method having, for example, a weaving process of weaving glass filaments to obtain a glass cloth, and an opening process of opening the glass filaments of the glass cloth can be listed. In addition, a desizing process of removing a sizing agent attached to the glass filaments of the glass cloth, a surface treatment process using a silane coupling agent can be provided as necessary.

[0124] The weaving method is not particularly limited as long as the weft yarn and the warp yarn are woven in a manner to form a predetermined woven structure. In addition, the fabric opening method is not particularly limited, and examples of the opening method include a method of performing opening processing using spray water (high-pressure water opening), an oscillating washing machine, ultrasonic water, a padding machine, and the like. Further, the desizing method is not particularly limited, and examples of the desizing method include a method of removing a sizing agent by heating. In addition, as the surface treatment method, a method of bringing a surface treatment agent containing a silane coupling agent into contact with the glass cloth and performing drying, and the like can be given. Note that the contact of the surface treatment agent with the glass cloth can be performed by a method of impregnating the glass cloth in the surface treatment agent, a method of applying the surface treatment agent to the glass cloth using a roll coater, a die coater, a gravure coater, or the like, and the like. The drying method of the surface treatment agent is not particularly limited, and examples of the drying method include a hot air drying method, a drying method using electromagnetic waves, and the like.

[0125] [Prepreg]

[0126] The prepreg of the present embodiment has the glass cloth described above and a matrix resin composition impregnated in the glass cloth. The prepreg having the glass cloth described above has a low risk of breakage during the manufacturing process and a high yield of finished products.

[0127] The prepreg of the present embodiment can be manufactured according to a conventional method. For example, the prepreg of the present embodiment can be manufactured by impregnating a varnish in which a matrix resin such as an epoxy resin is diluted with an organic solvent in the glass cloth of the present embodiment, volatilizing the organic solvent using a drying oven, and curing the thermosetting resin to a B-stage state (semi-cured state).

[0128] As the matrix resin composition, in addition to the epoxy resin described above, a thermosetting resin such as a bismaleimide resin, a cyanate ester resin, an unsaturated polyester resin, a polyimide resin, a BT resin, a functionalized polyphenylene ether resin, and the like; a thermoplastic resin such as a polyphenylene ether resin, a polyetherimide resin, a liquid crystal polymer (LCP) of a wholly aromatic polyester, a polybutadiene, a fluororesin, and the like; and a mixed resin thereof can be given. From the viewpoint of improving dielectric properties, heat resistance, solvent resistance, and press formability, as the matrix resin composition, a resin in which a thermoplastic resin is modified with a thermosetting resin can be used.

[0129] In addition, the matrix resin composition can contain, in the resin, an inorganic filler such as silicon dioxide and aluminum hydroxide; a flame retardant such as a bromine-based flame retardant, a phosphorus-based flame retardant, and a metal hydroxide; another silane coupling agent; a heat stabilizer; an antistatic agent; an ultraviolet absorber; a pigment; a colorant; a lubricant; and the like.

[0130] [Printed wiring board]

[0131] The printed wiring board of the present embodiment is provided with the prepreg described above. The printed wiring board provided with the prepreg of the present embodiment has a high yield of finished products, and can provide stable supply.

[0132] Examples

[0133] The present application is described in more detail below using examples and comparative examples. The present application is not limited in any way by the examples below.

[0134] <Warping Conditions>

[0135] The warping conditions A to F set in the examples and comparative examples are described below.

[0136] A: Setting of the same warp thread tension in the width direction

[0137] B: Setting of the warp thread tension 1.1 times stronger at both end portions of 15 cm than the tension at the central portion

[0138] C: Setting of the warp thread tension 1.1 times weaker at both end portions of 15 cm than the tension at the central portion

[0139] D: Setting of the warp thread tension 1.1 times weaker at both end portions of 30 cm than the tension at the central portion

[0140] E: Setting of the same warp thread tension in the width direction

[0141] F: Setting of the warp thread tension 1.1 times weaker at both end portions of 15 cm than the tension at the central portion

[0142] [Physical properties of glass filaments and glass cloth]

[0143] For the physical properties of the glass filaments and the glass cloth, specifically, the thickness of the glass cloth, the TEX of the glass filaments, the breaking strength (tensile strength) of the glass filaments, and the beating-up density (fabric density) of the warp and weft threads were measured according to JIS R3420.

[0144] [Strength confirmation test of glass cloth]

[0145] Based on the results of the manufacturing test of the glass cloth in the examples and comparative examples, the breaking risk of the glass cloth was evaluated by the following evaluation criteria.

[0146] : None of the 5 pieces broke or cracked, and the surface treatment / fiber opening process could be performed.

[0147] : None of the 5 pieces broke, but the surface treatment / fiber opening process could not be performed because one or more pieces cracked

[0148] : Only one piece broke, but the surface treatment / fiber opening process could be performed because the remaining 4 pieces did not break

[0149] : Two or more pieces broke.

[0150] Note that the breaking means that one piece of cloth is separated into at least two discontinuous parts, and the breaking means that a part maintaining continuity in one piece of cloth reaches a state of breaking, splitting, or the like. Figure 2

[0151] [Comparative Example 1]

[0152] Low dielectric glass filaments of TEX 1.46 were beamed under the same setting of the beaming conditions A in which the warp filament tension in the width direction was the same, and then woven using an air jet loom to obtain glass cloth greige goods 5 rolls having a warp filament density of 94.5 filaments / 25 mm, a weft filament density of 95.5 filaments / 25 mm, and a length of 2000 m.

[0153] Next, after the glass cloth was subjected to a pre-desizing treatment, the glass cloth was wound under the normal conditions a, and then subjected to a desizing treatment by heating.

[0154] Next, the cloth was impregnated with a silane coupling agent, and the silane coupling agent was applied using a liquid pressing roller α, and then subjected to a drying process and a fiber opening process to produce glass cloth 5 rolls having a thickness of 15 μm and a width of 1285 mm.

[0155] One roll of the glass cloth was broken during the production process.

[0156] [Comparative Example 2]

[0157] The warp filaments were beamed under the beaming conditions B in which the warp filament tension distribution in the width direction was adjusted, and otherwise, glass cloth 5 rolls having a thickness of 15 μm and a width of 1285 mm were produced using the same method as in Comparative Example 1.

[0158] Three rolls of the glass cloth were broken during the production process.

[0159] [Example 1]

[0160] The warp filaments were beamed under the beaming conditions C in which the warp filament tension distribution in the width direction was adjusted, and otherwise, glass cloth 5 rolls having a thickness of 15 μm and a width of 1285 mm were produced using the same method as in Comparative Example 1.

[0161] Glass cloth 5 rolls in which no breaking occurred could be obtained. However, two rolls of the glass cloth were broken.

[0162] [Example 2]

[0163] After the glass cloth was subjected to a pre-desizing treatment, the glass cloth was wound under the winding conditions b in which the force for expanding the glass cloth was applied so as to release the contraction of the glass cloth, and otherwise, glass cloth 5 rolls having a thickness of 15 μm and a width of 1285 mm were produced using the same method as in Example 1. ​

[0164] The glass cloth of superior quality, in which no breakage or rupture occurred, was stably obtained in 5 rolls.

[0165] [Example 3]

[0166] The warp yarns were beamed under the beaming condition D in which the warp yarn tension distribution in the width direction was adjusted, and the liquid press roller β in which the roller diameter of both end portions was smaller than that of the central portion was used to adjust the coating amount of the silane coupling agent, and otherwise, the glass cloth of 5 rolls having a thickness of 15 μm and a width of 1285 mm was manufactured by the same method as that of Example 1.

[0167] The glass cloth of superior quality, in which no breakage or rupture occurred, was stably obtained in 5 rolls.

[0168] [Example 4]

[0169] The warp yarns were beamed under the beaming condition D in which the warp yarn tension distribution in the width direction was adjusted, and the liquid press roller β in which the roller diameter of both end portions was smaller than that of the central portion was used to adjust the coating amount of the silane coupling agent, and otherwise, the glass cloth of 5 rolls having a thickness of 15 μm and a width of 1285 mm was manufactured by the same method as that of Example 1.

[0170] The glass cloth in which no breakage occurred was obtained in 5 rolls. However, the glass cloth was ruptured in 3 rolls.

[0171] [Comparative Example 3]

[0172] The E glass yarn of TEX 1.46 was beamed under the beaming condition E in which the warp yarn tension distribution in the width direction was adjusted, and then, a glass cloth base fabric of 5 rolls having a warp fabric density of 94.5 ends / 25 mm, a weft fabric density of 94.5 ends / 25 mm, and a length of 2000 m was obtained by using an air jet loom.

[0173] Then, the glass cloth was subjected to the pre-desizing treatment, and then, was wound under the normal condition a, and then, was subjected to the desizing treatment by heating.

[0174] Then, the glass cloth was impregnated with the silane coupling agent, and the coating amount of the silane coupling agent was adjusted by using the liquid press roller α, and then, the glass cloth of 5 rolls having a thickness of 11 μm and a width of 1285 mm was manufactured by passing through the drying process and the opening process.

[0175] The glass cloth was ruptured in 3 rolls in the middle of the process.

[0176] [Example 5]

[0177] The warp yarns were warped under the warping conditions F in which the width direction warp yarn tension distribution was adjusted, and after the glass cloth was subjected to a pre-desizing treatment, the glass cloth was wound up while a force to expand the glass cloth was applied to release the shrinkage of the glass cloth, and the glass cloth was wound up under the winding conditions b, and in order to adjust the coating amount of the silane coupling agent, the liquid press roller β was used, which had a smaller roller diameter at both ends than at the center, and otherwise, the glass cloth 5 having a thickness of 11 μm and a width of 1285 mm was manufactured in the same manner as in Comparative Example 3.

[0178] The high quality glass cloth in which none of the 5 rolls were broken or ruptured was stably obtained.

[0179] [Table 1]

[0180]

[0181] In Examples 1 to 5 in which the elongation of the warp direction at both ends of the glass cloth was large, none of the 5 rolls were broken, and the glass cloth was stably manufactured.

[0182] However, in Example 1 in which the breaking strength under the wet state was slightly low, 2 rolls were ruptured, and in Example 4 in which the elongation of the central region was not larger than the elongation of the both end regions, 3 rolls were ruptured. In contrast, in Examples 2 and 3 in which the breaking strength under the wet state was sufficiently large and the elongation of the central region was larger than the elongation of the both end regions, none of the glass cloths were ruptured, and high quality glass cloths were stably obtained.

[0183] In Comparative Examples 1 to 3 in which the elongation of the warp direction at both end regions of the glass cloth was small, the glass cloths were broken during the manufacturing process.

Claims

1. A glass cloth comprising a specific region having an elongation of 1.4% or more and 4.0% or less until reaching a breaking point when a tensile stress is applied in the warp direction in both end regions in the width direction, the both end regions in the width direction being regions from the edges in the width direction along the width direction until 15 cm from the both ends toward the center.

2. The glass cloth of claim 1, wherein, The glass cloth has a length in the width direction of 1000 mm or more and 1500 mm or less, and a thickness of 5 μm or more and 20 μm or less.

3. The glass cloth of claim 1 or 2, wherein, The elongation in the both end regions in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction is 1.7% or more in both end regions.

4. The glass cloth of claim 1 or 2, wherein, The elongation in the both end regions in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction is 4.0% or less in both end regions.

5. The glass cloth of claim 1 or 2, wherein, The elongation in the both end regions in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction is 2.0% or more and 3.7% or less in both end regions.

6. The glass cloth of claim 1 or 2, wherein, The elongation in the both end regions in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction is 2.3% or more and 3.2% or less in both end regions.

7. The glass cloth of claim 1 or 2, wherein, The elongation in the central region in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction is more than 0.1% larger than the elongation in the both end regions in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction.

8. The glass cloth of claim 1 or 2, wherein, The elongation in the central region in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction is more than 0.15% larger than the elongation in the both end regions in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction.

9. The glass cloth of claim 1 or 2, wherein, The elongation in the central region in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction is more than 0.2% larger than the elongation in the both end regions in the width direction until reaching a breaking point when a tensile stress is applied in the warp direction.

10. The glass cloth of claim 1 or 2, wherein, At least a part of the specific region exists at a symmetrical position sandwiching the MD center line in the both end regions in the width direction.

11. The glass cloth of claim 1 or 2, wherein, The breaking strength in the both end regions in the width direction when a tensile stress is applied in the warp direction is 30 N / 25 mm or more.

12. The glass cloth of claim 1 or 2, wherein, The breaking strength in the both end regions in the width direction when a tensile stress is applied in the warp direction is 35 N / 25 mm or more.

13. The glass cloth of claim 1 or 2, wherein, The breaking strength in the both end regions in the width direction when a tensile stress is applied in the warp direction is 40 N / 25 mm or more.

14. The glass cloth of claim 1 or 2, wherein, The breaking strength in the both end regions in the width direction when a tensile stress is applied in the warp direction is 50 N / 25 mm or more.

15. The glass cloth of claim 1 or 2, wherein, The breaking strength in the both end regions in the width direction when a tensile stress is applied in the warp direction in a state of being wetted with water is 20 N / 25 mm or more.

16. The glass cloth of claim 1 or 2, wherein, The breaking strength in the both end regions in the width direction when a tensile stress is applied in the warp direction in a state of being wetted with water is 30 N / 25 mm or more.

17. The glass cloth of claim 1 or 2, wherein, The breaking strength of the two end regions in the width direction when the tensile stress is applied in the direction of the filament is 40 N / 25 mm or more in a state of being wetted with water.

18. The glass cloth of claim 1 or 2, wherein, The average diameter of the filaments of the glass filaments constituting the glass cloth is 5 μm or less, and the number of filaments is 30 to 70.

19. The glass cloth of claim 1 or 2, wherein, The glass cloth has a length in the width direction of 1000 mm or more and 1500 mm or less, and a thickness of 8 μm or more and 18 μm or less.

20. The glass cloth according to claim 1 or 2, which has an elastic modulus of more than 0 and 70 GPa or less.

21. The glass cloth according to claim 1 or 2, which has an elastic modulus of 50 GPa or more and 70 GPa or less.

22. The glass cloth according to claim 1 or 2, which has an elastic modulus of 53 GPa or more and 70 GPa or less.

23. The glass cloth according to claim 1 or 2, which has an elastic modulus of 53 GPa or more and 63 GPa or less.

24. A roll-shaped glass cloth which is obtained by winding the glass cloth according to any one of claims 1 to 23.

25. The roll of glass cloth of claim 24, wherein, At least a part of the specific region is present at a position close to the innermost periphery between the outermost periphery and the innermost periphery of the roll.

26. A prepreg having the glass cloth according to any one of claims 1 to 23, and a matrix resin impregnated in the glass cloth.

27. A printed wiring board having the prepreg according to claim 26.

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