Rolled glass cloth

Abstract

The present invention provides a rolled glass cloth in which rippling deformation does not occur in a long glass cloth even when unrolled under strong tension of approximately 15 kgf. In a rolled glass cloth 1 according to the present invention, a long glass cloth 3 in which glass fibers formed from a plurality of glass filaments serve as warp and weft yarns is wound in the length direction thereof around a core tube 2. In the rolled glass cloth 1, the difference between the maximum and minimum values of the winding hardness in each of the 0°, 90°, 180°, and 270° directions with respect to the vertical direction is 2.9 or less in a middle layer 4 of the rolled glass cloth 1 in which 50% of the total length of the long glass cloth 3 in the length direction is wound around the core tube 2.

Description

Rolled glass cloth

[0001] The present invention relates to a roll of glass cloth.

[0002] In general, glass cloth used for printed wiring boards and the like is distributed in the form of a roll of glass cloth, which is a long glass cloth wound around a core tube. As the roll of glass cloth, a long glass cloth roll having a thickness of 8 μm or more and 100 μm or less, a winding hardness of 45 or more and 70 or less, and a width reduction of minus 0.5% or more and less than 0.1% has been known (see, for example, Patent Document 1).

[0003] According to the roll-shaped long glass cloth described in Patent Document 1, even if the elastic modulus of the glass cloth is small, distortion of the woven structure such as wrinkles is suppressed, resulting in excellent roll quality, and it is possible to provide a glass cloth with small variation in dimensional change during the process of producing a printed wiring board.

[0004] Japanese Patent Application Laid-Open No. 2021-11340

[0005] However, even if the long glass cloth in a roll form described in Patent Document 1 does not have distortion in the woven structure such as wrinkles when it is wound around a core tube or when it is unwound with a weak tension of less than 15 kgf, when it is unwound with a strong tension of about 15 kgf, a compressive force is generated in the width direction of the long glass cloth due to the Poisson effect, and this compressive force causes wavy buckling (deformation) in the width direction of the long glass cloth, which is an inconvenience.

[0006] The Poisson effect refers to the phenomenon in which, when a uniaxial stress acts on an object in the z-axis direction, the object stretches in the z-axis direction due to its elasticity, generating a longitudinal strain εz, and, incidentally, transverse strains εx and εy also occur in the x-axis and y-axis directions, which are perpendicular to the z-axis.

[0007] An object of the present invention is to eliminate such inconveniences and to provide a roll-shaped glass cloth which does not undergo wavy buckling in the width direction of the long glass cloth even when unwound under a strong tension of about 15 kgf.

[0008] In order to achieve this object, the roll-shaped glass cloth of the present invention is a roll-shaped glass cloth in which a long glass cloth having glass fibers consisting of a plurality of glass filaments as warp and weft threads is wound around a core tube in the longitudinal direction, wherein 50% of the total length of the long glass cloth in the longitudinal direction is wound around the core tube, and the difference between the maximum and minimum winding hardness in each of the directions of 0°, 90°, 180° and 270° with respect to the vertical direction in a middle layer of the roll-shaped glass cloth is 2.9 or less.

[0009] According to the roll-shaped glass cloth of the present invention, the difference between the maximum and minimum values ​​of winding hardness in the directions of 0°, 90°, 180° and 270° with respect to the vertical direction in the middle layer of the roll-shaped glass cloth is 2.9 or less, and therefore, even when the glass cloth is unwound under a strong tension of about 15 kgf, it is possible to prevent the occurrence of wavy buckling in the width direction of the long glass cloth.

[0010] In addition, in the roll-shaped glass cloth of the present invention, the entire length of the long glass cloth in the longitudinal direction is preferably wound around the core tube, and the surface layer of the roll-shaped glass cloth has a winding hardness of more than 70.

[0011] The prepreg of the present invention is characterized by including at least a part of the long glass cloth constituting the roll-shaped glass cloth of the present invention, and the printed wiring board of the present invention is characterized by including at least a part of the long glass cloth constituting the roll-shaped glass cloth of the present invention. In this case, the at least a part of the long glass cloth may be a glass cloth obtained by unwinding the roll-shaped glass cloth of the present invention.

[0012] 1 is a front view showing a roll-shaped glass cloth of the present invention.

[0013] Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0014] 1 and 2, a roll-shaped glass cloth 1 of this embodiment has a core tube 2 in the center, and a long glass cloth 3 is wound around the core tube 2 in the longitudinal direction. The long glass cloth 3 is woven using glass fibers consisting of a plurality of glass filaments as warp and weft yarns, and has, for example, a width in the range of 500 to 2000 mm, a thickness in the range of 6 to 200 μm, and a length of 200 to 5000 m.

[0015] The width of the long glass cloth 3 is preferably in the range of 800 to 1600 mm, and more preferably in the range of 1000 to 1400 mm.

[0016] The thickness of the long glass cloth 3 is preferably in the range of 8 to 80 μm, more preferably 9 to 14 μm, from the viewpoint of preventing collapse of the winding or buckling in a wavy manner.

[0017] The length of the long glass cloth 3 is preferably in the range of 500 to 2500 m, more preferably in the range of 800 to 1300 m. When the length of the long glass cloth 3 is in the above range, the effect of reducing wavy buckling can be sufficiently obtained.

[0018] In the roll-shaped glass cloth 1, a length of 0.5L, which is 50% of the total length L of the long glass cloth 3 in the longitudinal direction, is wound around the core tube 2, and the difference between the maximum and minimum winding hardness in each of the directions of 0°, 90°, 180°, and 270° with respect to the vertical direction (directions A to D indicated by arrows in Fig. 2) in the middle layer 4 is 2.9 or less. In other words, as shown by the imaginary line in Fig. 2, the middle layer 4 is in a state where a length of 0.5L is unwound from the surface layer 5 in a state where the total length L of the long glass cloth 3 in the longitudinal direction is wound around the core tube 2.

[0019] The winding hardness of the intermediate layer 4 can be measured as follows. First, as shown in Fig. 2, a rubber hardness tester (manufactured by Kobunshi Keiki Co., Ltd., product name: Asker Rubber Hardness Tester Type C) is pressed against a region a of the intermediate layer 4 of the rolled glass cloth 1 corresponding to direction A from a direction A that is 0° relative to the vertical, thereby measuring the winding hardness in the direction 0° relative to the vertical. Specifically, in the width direction including region a of the rolled glass cloth 1, the winding hardness is measured at a plurality of regions at 10 cm intervals from a region 5 cm inward from one end of the rolled glass cloth 1 in the width direction to a region 5 cm inward from the other end, or from a region less than 15 cm to 5 cm or more inward from the other end, and the average value thereof is taken as the winding hardness in the direction 0° relative to the vertical.

[0020] Next, the rolled glass cloth 1 is rotated 90° counterclockwise in FIG. 2 to unwind a length corresponding to ¼ of the circumference of the middle layer 4, and the portion b corresponding to the direction B shown in FIG. 2 is moved to the portion corresponding to the portion a. The winding hardness in the direction at an angle of 90° to the vertical direction is measured by carrying out the same operation as in the measurement of the winding hardness in the direction at an angle of 0° to the vertical direction.

[0021] Similarly, the rolled glass cloth 1 is rotated another 90° (total 180°) to the left in FIG. 2 , and is further unwound by a length that is ¼ of the circumference of the middle layer 4 (total ½), and the portion c corresponding to direction C shown in FIG. 2 is moved to a portion corresponding to portion a, and the winding hardness in the direction at an angle of 180° to the vertical direction is measured. The rolled glass cloth 1 is rotated another 90° (total 270°) to the left in FIG. 2 , and is further unwound by a length that is ¼ of the circumference of the middle layer 4 (total ¾), and the portion d corresponding to direction D shown in FIG. 2 is moved to a portion corresponding to portion a, and the winding hardness in the direction at an angle of 270° to the vertical direction is measured.

[0022] In the middle layer 4 of the roll-shaped glass cloth 1, the difference between the maximum and minimum values ​​of winding hardness in each of the directions of 0°, 90°, 180°, and 270° with respect to the vertical direction (directions A to D indicated by arrows in FIG. 2) is more preferably 1.0 or less, from the viewpoint of further suppressing the occurrence of wavy buckling.

[0023] Furthermore, the average winding hardness of the intermediate layer 4 of the roll-shaped glass cloth 1 in each of the directions of 0°, 90°, 180°, and 270° with respect to the vertical direction is preferably in the range of 62.0 or more, more preferably in the range of more than 70.0, and even more preferably in the range of 71.4 or more, from the viewpoint of preventing collapse of the roll-shaped glass cloth 1. Note that collapse of winding refers to a phenomenon in which, when the long glass cloth 3 is wound around the core tube 2 or when the roll-shaped glass cloth 1 wound around the core tube 2 is transported, external disturbances cause slippage between layers of the wound long glass cloth 3 in the axial direction of the core tube 2, resulting in deformation of the end face of the wound roll-shaped glass cloth 1 into a truncated cone shape.

[0024] Furthermore, in the roll-shaped glass cloth 1, the winding hardness of the surface layer 5 in a state in which the entire length L of the long glass cloth 3 in the longitudinal direction is wound around the core tube 2 is preferably in the range of 62.0 or more, more preferably in the range of 68.4 or more, even more preferably in the range of more than 70.0, and particularly preferably in the range of 71.4 or more, from the viewpoint of preventing unwinding of the roll-shaped glass cloth 1. The winding hardness of the surface layer 5 can be determined by measuring the winding hardness in each of directions of 0°, 90°, 180°, and 270° with respect to the vertical direction in the same manner as in the measurement of the winding hardness of the middle layer 4 in a state in which the entire length L of the long glass cloth 3 in the longitudinal direction is wound around the core tube 2, and calculating the average value of the winding hardness in each direction.

[0025] The roll-shaped glass cloth 1 of this embodiment can be produced, for example, as follows.

[0026] First, a predetermined glass batch (glass raw material) is melted and fiberized to obtain glass filaments. The diameter of the glass filaments is not particularly limited, but for printed wiring board applications, it is preferably 10 μm or less, more preferably 8 μm or less, and particularly preferably in the range of 3 to 5 μm.

[0027] The glass filaments are bundled into a glass fiber by a method known per se, for example, in a number ranging from 25 to 500, preferably from 40 to 300. Note that the process of melting a glass batch, fiberizing it to obtain glass filaments, and then bundling a plurality of these glass filaments to obtain a glass fiber is called spinning.

[0028] The glass composition of the glass fiber is not particularly limited, but examples thereof include the most commonly used E-glass composition, a high-strength, high-elasticity glass composition, a high-elasticity, easily manufacturable glass composition, a low-dielectric-constant, low-dielectric-loss-tangent glass composition, and a low-thermal-expansion, low-dielectric-constant glass composition.

[0029] The E-glass composition contains SiO in the range of 52.0 to 56.0 mass % based on the total amount of glass fibers. ２ and Al in the range of 12.0 to 16.0 mass% ２ O ３ and a total of 20.0 to 25.0 mass% of MgO and CaO, and 5.0 to 10.0 mass% of B. ２ O ３ The composition includes:

[0030] The high-strength, high-elasticity glass composition contains SiO in the range of 60.0 to 70.0 mass % based on the total amount of glass fibers. ２ and Al in the range of 20.0 to 30.0 mass% ２ O ３ and MgO in the range of 5.0 to 15.0 mass % and Fe in the range of 0 to 1.5 mass %. ２ O ３ and a total of 0 to 0.2 mass% of Na ２ O.K. ２ O and Li ２ The high strength and high modulus glass composition preferably contains 0.15 to 1.50 mass % of Fe. ２ O ３ and ZrO in the range of 0.01 to 0.10 mass %. ２ and a total of 0.02 to 0.20 mass% of Na ２ O.K. ２ O and Li ２ O.

[0031] The high elastic modulus, easily manufacturable glass composition contains SiO in the range of 57.0 to 60.0 mass % based on the total amount of glass fibers. ２ and Al in the range of 17.5 to 20.0 mass% ２ O ３ 8.5 to 12.0 mass% MgO, 10.0 to 13.0 mass% CaO, and 0.5 to 1.5 mass% B ２ O ３ and a total of 98.0 mass% or more of SiO ２ , Al ２ O ３ , MgO and CaO.

[0032] The low dielectric constant and low dielectric loss tangent glass composition contains SiO in the range of 48.0 to 62.0 mass % based on the total amount of glass fibers. ２ and B in the range of 17.0 to 26.0 mass% ２ O ３ and Al in the range of 9.0 to 18.0 mass% ２ O ３ 0.1 to 9.0 mass% CaO, 0 to 6.0 mass% MgO, and 0 to 0.5 mass% Na in total. ２ O.K. ２ O and Li ２ O and TiO in the range of 0 to 5.0 mass% ２ and SrO in the range of 0 to 6.0 mass %, and F in the range of 0 to 3.0 mass % in total. ２ and Cl ２ and P in the range of 0 to 6.0 mass%. ２ O ５ The composition includes:

[0033] The low thermal expansion and low dielectric constant glass composition contains SiO in the range of 42.0 to 63.0 mass % based on the total amount of glass fibers. ２ and Al in the range of 19.0 to 27.3 mass% ２ O ３ ZnO in the range of more than 3.00 mass% and not more than 13.00 mass%, and P in the range of 6.50 to 19.0 mass%. ２ O ５ and MgO in the range of 0.00 to 7.00 mass%, and Li in the range of 1.00 mass% or less in total. ２ O, Na ２ O and K２ O.

[0034] The content of each component of the glass composition described above can be measured using an ICP optical emission spectrometer for the light element Li, and using a wavelength dispersive X-ray fluorescence analyzer for the other elements. Specifically, the content of each component of the glass composition can be measured as follows.

[0035] First, glass cloth is cut to an appropriate size, placed in a platinum crucible, and melted in an electric furnace at a temperature of 1400 to 1650°C for 6 hours while stirring, to obtain a homogeneous molten glass. If organic matter is attached to the surface of the glass cloth or if glass fibers are contained mainly as a reinforcing material in the organic matter (resin), the glass cloth is used after removing the organic matter by, for example, heating in a muffle furnace at 300 to 650°C for 2 to 24 hours.

[0036] The molten glass is then poured onto a carbon plate to produce glass cullet, which is then crushed and powdered to produce glass powder. The light element Li is quantitatively analyzed using an ICP optical emission spectrometer after the glass powder is thermally decomposed with acid. The other elements are quantitatively analyzed using a wavelength dispersive X-ray fluorescence analyzer after the glass powder is molded into a disk shape using a press.

[0037] First, the content of each component in the measurement sample is measured by the fundamental parameter method. Next, based on the measurement results, at least three calibration curve samples are prepared and analyzed by the calibration curve method. The content of each component in the calibration curve samples can be quantitatively analyzed, for example, using an IPC optical emission spectrometer.

[0038] Next, the results of these quantitative analyses are converted into oxides to calculate the content and total amount of each component, and the content (mass %) of each component described above can be determined from these values.

[0039] The elastic modulus of the glass fibers constituting the glass filaments is not particularly limited, but is, for example, in the range of 40 to 120 GPa. Since conventional glass filaments have tended to easily collapse or buckle in a wavy pattern, from the viewpoint of more pronounced effects of the present invention, the elastic modulus is preferably in the range of 45 to 70 GPa, and more preferably in the range of 62 to 68 GPa. Furthermore, the strength of the glass fibers constituting the glass filaments is not particularly limited, but is, for example, in the range of 1.5 to 6.0 GPa, and preferably in the range of 2.0 to 4.5 GPa.

[0040] The elastic modulus and strength of the glass fibers constituting the glass filaments can be measured by the method described in the Examples below.

[0041] The mass per unit length of the glass fiber is, for example, preferably in the range of 0.6 to 135 g / 1000 m, more preferably in the range of 0.7 to 25 g / 1000 m, and from the viewpoint of preventing collapse of winding or wavy buckling, is further preferably in the range of 0.8 to 3.8 g / 1000 m, and particularly preferably in the range of 0.9 to 1.4 g / 1000 m.

[0042] Next, the glass fibers are used as warp or weft yarns and woven using a known loom to obtain a long glass cloth 3. Examples of the loom include jet looms such as air jet or water jet looms, shuttle looms, and rapier looms. Examples of weaving methods used with the loom include plain weave, satin weave, sash weave, and twill weave, with plain weave being preferred from the viewpoint of manufacturing efficiency. The weaving density of the glass fiber yarns used in the weaving is not particularly limited, but is preferably in the range of 10 to 150 threads / 25 mm, and more preferably in the range of 40 to 100 threads / 25 mm.

[0043] During the weaving process, a sizing agent can be used to bundle the glass filaments and protect the glass fibers. Examples of the sizing agent include starch-based or PVA (polyvinyl alcohol)-based sizing agents. The sizing agent may contain an oil agent, a softener, or the like.

[0044] The amount of the sizing agent attached to the glass cloth is, for example, preferably in the range of 0.1 to 3 parts by mass, and more preferably in the range of 0.5 to 1.5 parts by mass, per 100 parts by mass of the glass fiber yarn.

[0045] After being woven, the long glass cloth 3 may be subjected to a de-oiling treatment, a surface treatment, and a fiber-opening treatment.

[0046] The deoiling treatment may be, for example, a treatment in which the long glass cloth 3 is placed in a heating furnace at an atmospheric temperature of 350° C. to 400° C. for 40 to 80 hours to thermally decompose organic matter adhering to the glass fibers.

[0047] The surface treatment may include a treatment in which the glass cloth is immersed in a silane coupling agent or a solution containing the silane coupling agent and a surfactant, excess water is squeezed out, and the glass cloth is then heated and dried at a temperature in the range of 80 to 180°C for 0.2 to 30 minutes, preferably 1 to 30 minutes.

[0048] Examples of the silane coupling agent include aminosilane, ureidosilane, chlorosilane, epoxysilane, mercaptosilane, vinylsilane, (meth)acrylicsilane, phenylsilane, styrylsilane, and isocyanatesilane. In this embodiment, the silane coupling agent may be used alone or in combination of two or more.

[0049] Examples of aminosilanes include γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-N'-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and γ-anilinopropyltrimethoxysilane.

[0050] Examples of ureidosilane include γ-ureidopropyltriethoxysilane.

[0051] Examples of chlorosilanes include γ-chloropropyltrimethoxysilane.

[0052] Examples of epoxy silanes include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane.

[0053] Examples of mercaptosilane include γ-mercaptotrimethoxysilane and γ-mercaptopropyltrimethoxysilane.

[0054] Examples of vinylsilanes include vinyltrimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, and N-benzyl-β-aminoethyl-γ-aminopropyltrimethoxysilane.

[0055] Examples of the (meth)acrylic silane include γ-acryloxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

[0056] Examples of phenylsilane include phenyltrimethoxysilane.

[0057] The styrylsilane may include p-styryltrimethoxysilane.

[0058] Examples of isocyanate silanes include γ-isocyanate propyl triethoxy silane.

[0059] Examples of the surfactant include nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants. In this embodiment, the surfactants may be used alone or in combination of two or more.

[0060] Examples of nonionic surfactants include ethylene oxide propylene oxide alkyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene-polyoxypropylene block copolymers, alkyl polyoxyethylene-polyoxypropylene block copolymer ethers, polyoxyethylene fatty acid esters, polyoxyethylene fatty acid monoesters, polyoxyethylene fatty acid diesters, polyoxyethylene sorbitan fatty acid esters, glycerol fatty acid ester ethylene oxide adducts, polyoxyethylene castor oil ethers, hydrogenated castor oil ethylene oxide adducts, alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts, glycerol fatty acid esters, polyglycerin fatty acid esters, pentaerythritol fatty acid esters, sorbitol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyhydric alcohol alkyl ethers, fatty acid alkanolamides, acetylene glycol, acetylene alcohol, ethylene oxide adducts of acetylene glycol, and ethylene oxide adducts of acetylene alcohol.

[0061] Examples of cationic surfactants include alkyldimethylbenzylammonium chloride, alkyltrimethylammonium chloride, alkyldimethylethylammonium ethyl sulfate, higher alkylamine salts (acetates, hydrochlorides, etc.), ethylene oxide adducts of higher alkylamines, condensates of higher fatty acids and polyalkylenepolyamines, salts of esters of higher fatty acids and alkanolamines, salts of higher fatty acid amides, imidazoline-type cationic surfactants, and alkylpyridinium salts.

[0062] Examples of anionic surfactants include higher alcohol sulfates, higher alkyl ether sulfates, α-olefin sulfates, alkylbenzene sulfonates, α-olefin sulfonates, reaction products of fatty acid halides and N-methyltaurine, dialkyl sulfosuccinates, higher alcohol phosphates, and phosphate salts of higher alcohol ethylene oxide adducts.

[0063] Examples of amphoteric surfactants include amino acid type amphoteric surfactants such as alkali metal salts of alkylaminopropionic acid, betaine type amphoteric surfactants such as alkyldimethylbetaine, and imidazoline type amphoteric surfactants.

[0064] Examples of the opening treatment include a treatment for widening the yarn width of the warp and weft yarns by applying a tension of 20 to 200 N to the warp yarns of the long glass cloth 3, such as opening by water jet pressure, opening by high-frequency vibration using a liquid as a medium, opening by pressure of a fluid having a surface pressure, or opening by pressure using a roll.

[0065] Next, the woven long glass cloth 3 is wound around a core tube 2 with a predetermined winding tension, thereby obtaining a roll-shaped glass cloth 1 in which the long glass cloth 3 is wound around the core tube 2 in its length direction.

[0066] The winding tension at the start of winding is preferably in the range of 3 to 60 kgf, more preferably in the range of 5 to 55 kgf, and even more preferably in the range of 10 to 30 kgf. When the winding tension is 3 kgf or more at the start of winding, the average winding hardness can be increased and the winding is less likely to collapse, and when the winding tension is 60 kgf or less, the long glass cloth 3 can be wound while preventing the occurrence of winding wrinkles due to excessive tension.

[0067] The winding tension at the end of winding is preferably in the range of 3 to 60 kgf, more preferably in the range of 5 to 55 kgf, and even more preferably in the range of 10 to 30 kgf. By setting the winding tension at 3 kgf or more at the end of winding, the average winding hardness can be increased and the winding is less likely to collapse, and by setting the winding tension at 60 kgf or less, the long glass cloth 3 can be wound while preventing winding wrinkles due to excessive tension.

[0068] When the long glass cloth 3 is wound around the core tube 2, the long glass cloth 3 is pressed onto the core tube 2 by a plurality of press rollers spaced apart from each other so that the winding tensions at the start and end of winding are within the above-mentioned ranges, respectively. This makes it possible to make the difference between the maximum and minimum winding hardnesses in the middle layer 4 of the roll-shaped glass cloth 1 in each of the directions of 0°, 90°, 180°, and 270° with respect to the vertical direction 2.9 or less.

[0069] By winding the long glass cloth 3 while pressing it onto the core tube 2 with the multiple press rollers, local slack in the rolled glass cloth 1, which occurs when the press rollers retreat as the rolled glass cloth 1 thickens (increases in diameter), is prevented, and the difference between the maximum and minimum winding hardness in the middle layer 4 of the rolled glass cloth 1 in each of the directions of 0°, 90°, 180°, and 270° relative to the vertical direction can be reduced to 2.9 or less. If the long glass cloth 3 is wound onto the core tube 2 while pressing it onto the core tube 2 with only one press roller, there is a disadvantage that local slack occurs in the glass cloth 1 on the roll due to temporary insufficient pressure when the press roller retreats as the rolled glass cloth 1 thickens (increases in diameter).

[0070] When a plurality of press rollers are used, the pressure of each press roller is preferably in the range of 1 to 80 kgf, more preferably in the range of 2 to 65 kgf. When the pressure of each press roller is 1 kgf or more, the average winding hardness can be increased and the winding is less likely to collapse, and when the pressure is 80 kgf or less, the problem of the long glass cloth 3 being crushed by the press rollers while the slack of the long glass cloth 3 is not eliminated during winding can be eliminated, thereby causing wrinkles on the surface of the long glass cloth 3.

[0071] The prepreg of this embodiment includes at least a part of the long glass cloth 3 constituting the roll-shaped glass cloth 1 of this embodiment. The at least a part of the long glass cloth 3 may be a glass cloth obtained by unwinding the roll-shaped glass cloth 1 of this embodiment.

[0072] The prepreg of this embodiment can be obtained by impregnating at least a portion of the long glass cloth 3 constituting the roll-shaped glass cloth 1 of this embodiment with a resin by a method known per se and semi-curing the resin.

[0073] In the prepreg of this embodiment, there is no particular limitation on the resin impregnated into at least a portion of the long glass cloth 3. Examples of such resins include epoxy resin, phenol resin, unsaturated polyester resin, melamine resin, modified polyimide resin, polyamide resin, polyimide resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, polyphenylene ether resin, modified polyphenylene ether resin, and fluororesin.

[0074] The printed wiring board of this embodiment includes at least a part of the long glass cloth 3 constituting the roll-shaped glass cloth 1 of this embodiment. The at least a part of the long glass cloth 3 may be a glass cloth obtained by unrolling the roll-shaped glass cloth 1 of this embodiment.

[0075] The printed wiring board of this embodiment can be obtained, for example, by curing the prepreg of this embodiment described above.

[0076] Next, examples of the present invention and comparative examples will be described.

[0077] [Examples 1 to 5 and Comparative Example 1] First, glass cloths made of glass filaments having the glass compositions shown in Table 1 and corresponding to the cloth types of the IPC standards shown in Table 1 were woven, and then the glass cloths were subjected to a deoiling treatment, a surface treatment and a fiber-opening treatment, thereby obtaining long glass cloths 3 of Examples 1 to 5 and Comparative Example 1 each having a width of 1,270 mm and a length of 1,000 m.

[0078] Regarding the IPC standard cross type shown in Table 1, "1078" is a fabric with the following specifications: yarn used: D500 (filament diameter 5.0 μm, yarn weight 10.2 g / 1000 m), warp weave density: 53 threads / 25 mm, weft weave density: 53 threads / 25 mm, thickness: 44 μm, mass per unit area: 43 g / m ２ "1010" is a glass cloth having the following characteristics: yarn used: filament diameter 4.0 μm, yarn weight 1.32 g / 1000 m, warp weave density: 95 threads / 25 mm, weft weave density: 95 threads / 25 mm, thickness: 13 μm, mass per unit area: 9.9 g / m ２ The "1006" corresponds to a glass cloth having a yarn used: a yarn obtained by bundling 38 glass filaments having a filament diameter of 3.6 μm, a warp weave density of 105 threads / 25 mm, a weft weave density of 110 threads / 25 mm, and a thickness of 10 μm.

[0079] The 1006 type glass cloth made of glass filaments of composition A has a yarn weight of 0.89 g / 1000 m and a mass per unit area of ​​the glass cloth of 7.5 g / m. ２ In addition, the 1006 type glass cloth made of glass filaments of composition B had a weight of yarn used of 0.99 g / 1000 m, and the mass per unit area of ​​the glass cloth was 8.6 g / m. ２ It was.

[0080] Next, the long glass cloth 3 obtained in each of the Examples and Comparative Example 1 was treated under the production conditions shown in Table 1 to obtain roll-shaped glass cloth 1 of Examples 1 to 5 and Comparative Example 1.

[0081] Next, the winding hardness of the middle layer 4 or the surface layer 5 of the roll-shaped glass cloth 1 was measured by the method described below, and the wavy buckling in the width direction of the long glass cloth 3 and the collapse of the roll-shaped glass cloth 1 were evaluated. The results are shown in Table 1. In Table 1, the winding hardness of the surface layer 5 of the roll-shaped glass cloth 1 is described as "average," and the wavy buckling is described as "waviness."

[0082] Table 2 shows the details of the glass compositions A and B shown in Table 1, as well as the dielectric constant, linear expansion coefficient, tensile strength and tensile modulus of the glass filaments having each glass composition.

[0083] 2 , a rubber hardness tester (manufactured by Kobunshi Keiki Co., Ltd., trade name: Asker Rubber Hardness Tester Type C) was pressed against a region a in the middle layer 4 of the rolled glass cloth 1, which corresponds to direction A, from a direction A that is 0° relative to the vertical, to measure the winding hardness in the direction 0° relative to the vertical. Specifically, in the width direction including region a of the rolled glass cloth 1, the winding hardness was measured at a plurality of regions at 10 cm intervals from a region 5 cm inward from one end of the rolled glass cloth 1 in the width direction to a region 5 cm inward from the other end, and the average value was taken as the winding hardness in the direction 0° relative to the vertical.

[0084] Next, the roll-shaped glass cloth 1 was rotated 90° counterclockwise in FIG. 2 to unwind a quarter of the circumference of the middle layer 4, and the portion b corresponding to the direction B shown in FIG. 2 was moved to the portion corresponding to the portion a. The winding hardness in the direction at an angle of 90° to the vertical direction was measured by carrying out the same operation as in the measurement of the winding hardness in the direction at an angle of 0° to the vertical direction.

[0085] Similarly, the roll-shaped glass cloth 1 was rotated another 90° (total 180°) to the left in FIG. 2 , and was further unwound by a length that was ¼ of the circumference of the middle layer 4 (total ½), and the portion c corresponding to direction C shown in FIG. 2 was moved to a portion corresponding to portion a, and the winding hardness in the direction at an angle of 180° to the vertical direction was measured. The roll-shaped glass cloth 1 was rotated another 90° (total 270°) to the left in FIG. 2 , and was further unwound by a length that was ¼ of the circumference of the middle layer 4 (total ¾), and the portion d corresponding to direction D shown in FIG. 2 was moved to a portion corresponding to portion a, and the winding hardness in the direction at an angle of 270° to the vertical direction was measured.

[0086] In addition, the average value of the winding hardness in the directions of 0°, 90°, 180°, and 270° relative to the vertical direction was taken as the average winding hardness in the middle layer, and the differences between the maximum and minimum values ​​of the winding hardness in each of the directions of 0°, 90°, 180°, and 270° relative to the vertical direction were calculated from the maximum and minimum values ​​of the winding hardness in the directions of 0°, 90°, 180°, and 270° relative to the vertical direction.

[0087] In Table 1, the difference between the maximum and minimum values ​​of winding hardness in each direction of 0°, 90°, 180°, and 270° relative to the vertical direction is referred to as "maximum-minimum difference at 0°, 90°, 180°, and 270°."

[0088] In addition, when measuring the winding hardness in the direction at an angle of 0° to the vertical direction, the coefficient of variation of the winding hardness measured at a plurality of positions at 10 cm intervals from a position 5 cm inward from one end of the roll-shaped glass cloth 1 in the width direction to a position 5 cm inward from the other end was defined as the coefficient of variation of the winding hardness in the weft direction.

[0089] [Winding Hardness in Surface Layer] As shown by the imaginary line in Figure 2 , the entire length L of the long glass cloth 3 in the longitudinal direction of the surface layer 5 was wound around the core tube 2, and the winding hardness was measured in each of the directions of 0°, 90°, 180°, and 270° with respect to the vertical direction by performing the same operation as in the measurement of the winding hardness in the middle layer 4, and the winding hardness in the surface layer 5 was determined by calculating the average value of the winding hardness in each direction.

[0090] In addition, when measuring the winding hardness in the direction at an angle of 0° to the vertical direction, the coefficient of variation of the winding hardness measured at a plurality of positions at 10 cm intervals from a position 5 cm inward from one end of the roll-shaped glass cloth 1 in the width direction to a position 5 cm inward from the other end was defined as the coefficient of variation of the winding hardness in the weft direction.

[0091] [Wavy Buckling] While the roll-shaped glass cloth 1 was being unwound under a tension of 15 kgf, the appearance of the long glass cloth 3 was visually observed from the lengthwise direction to the widthwise direction. When three or more wavy bucklings with a height of 1 cm or more were found to have occurred at intervals of 10 cm or less and the bucklings occurred continuously or intermittently over a length of 3 m or more in the lengthwise direction, it was determined that wavy buckling had occurred.

[0092] At this time, samples in which no wavy buckling occurred along the entire length or in the area from the surface layer 5 to the part unwound at a length of 0.9L relative to the total length L were evaluated as "◎"; samples in which no wavy buckling occurred in the area from the surface layer 5 to the part unwound at a length of 0.5L relative to the total length L, but wavy buckling occurred in the area from the part unwound at a length of 0.5L relative to the total length L to the part unwound at a length of 0.9L relative to the total length L, were evaluated as "◯"; samples in which wavy buckling occurred in the area from the surface layer 5 to the part unwound at a length of 0.5L relative to the total length L, were evaluated as "×".

[0093]

[0094]

[0095] It is clear from Table 1 that the roll-shaped glass cloth 1 of Examples 1 to 5, in which the difference between the maximum and minimum values ​​of winding hardness in each of the directions of 0°, 90°, 180°, and 270° relative to the vertical is 2.9 or less, can prevent the occurrence of wavy buckling in the range from the surface layer 5 to the part unwound by a length of 0.5L relative to the total length L when unwound with a tension of 15 kgf. On the other hand, the roll-shaped glass cloth 1 of Comparative Example 1, in which the difference between the maximum and minimum values ​​of winding hardness in each of the directions of 0°, 90°, 180°, and 270° relative to the vertical is more than 2.9, cannot prevent the occurrence of wavy buckling in the range from the surface layer 5 to the part unwound by a length of 0.5L relative to the total length L when unwound with a tension of 15 kgf, even if the coefficient of variation of winding hardness in the weft direction is approximately the same as that of Examples 1 to 5.

[0096] 1...rolled glass cloth, 2...core tube, 3...long glass cloth, 4...middle layer, 5...surface layer.

Claims

1. A roll-shaped glass cloth in which a long glass cloth having glass fibers made of a plurality of glass filaments as warp and weft threads is wound around a core tube in the length direction, a difference between the maximum value and the minimum value of winding hardness in each of directions of 0°, 90°, 180° and 270° with respect to the vertical direction in an intermediate layer of the roll-shaped glass cloth, the intermediate layer being wound around the core tube by 50% of the total length in the longitudinal direction of the long glass cloth, being 2.9 or less; A rolled glass cloth, wherein the entire length of the long glass cloth in the longitudinal direction is wound around the core tube, and the surface layer of the rolled glass cloth has a winding hardness of more than 70.

2. A prepreg comprising at least a portion of the long glass cloth constituting the rolled glass cloth according to claim 1.

3. A printed wiring board comprising at least a portion of the long glass cloth constituting the roll of glass cloth according to claim 1.