Rolled glass cloth

Abstract

The present invention provides a roll-type glass cloth that does not undergo wavy deformation even when unfolded under a strong tension of approximately 15 kgf. [Solution] The rolled glass cloth 1 of the present invention consists of a long glass cloth 3 made of glass fibers consisting of multiple glass filaments as warp and weft threads, wound around a core tube 2 in the longitudinal direction. In the middle layer 4 of the rolled glass cloth 1, where 50% of the total length of the long glass cloth 3 is wound around the core tube 2, the difference between the maximum and minimum winding hardness in the directions of 0°, 90°, 180°, and 270° with respect to the vertical is 2.9 or less.

Description

Technical Field

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

Background Art

[0002] Generally, the glass cloth used for printed wiring boards and the like is distributed in the form of a roll-shaped glass cloth in which a long glass cloth is wound around a core tube. As the roll-shaped glass cloth, conventionally, a roll-shaped long glass cloth having a glass cloth 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 allowance of minus 0.5% or more and less than 0.1% is known (for example, see Patent Document 1).

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

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, even if there is no distortion of the woven structure such as wrinkles when the long glass cloth is wound around the core tube or when it is unwound with a weak tension of less than 15 kgf, as in the roll-shaped long glass cloth described in Patent Document 1, 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 there is a problem that the compressive force causes a wavy buckling (deformation) in the width direction of the long glass cloth.

[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's dimension in the z-axis direction elongates due to its elasticity, generating a longitudinal strain εz. As a result, transverse strains εx and εy are also generated in the x-axis and y-axis directions, which are perpendicular to the z-axis.

[0007] The present invention aims to eliminate these inconveniences and provide a roll of glass cloth that does not undergo wavy buckling in the width direction of a long length of glass cloth, even when unfolded under a strong tension of about 15 kgf. [Means for solving the problem]

[0008] To achieve this objective, the rolled glass cloth of the present invention is a rolled glass cloth in which a long glass cloth, consisting of glass fibers made of multiple 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 is wound around the core tube, and the difference between the maximum and minimum values ​​of the winding hardness in the middle layer of the rolled glass cloth in the directions of 0°, 90°, 180°, and 270° with respect to the vertical direction is 2.9 or less.

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

[0010] Furthermore, in the roll-shaped glass cloth of the present invention, it is preferable that the winding hardness of the surface layer of the roll-shaped glass cloth, where the entire length of the long glass cloth in the longitudinal direction is wound around the core tube, is greater than 70.

[0011] Furthermore, the prepreg of the present invention is characterized by including at least a portion of the long glass cloth that constitutes the roll-shaped glass cloth of the present invention, and the printed circuit board of the present invention is characterized by including at least a portion of the long glass cloth that constitutes the roll-shaped glass cloth of the present invention. In this case, the at least portion of the long glass cloth may be glass cloth obtained by unrolling the roll-shaped glass cloth of the present invention. [Brief explanation of the drawing]

[0012] [Figure 1] Front view showing the rolled glass cloth of the present invention. [Figure 2] Cross-sectional view along line II-II in Figure 1. [Modes for carrying out the invention]

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

[0014] As shown in Figures 1 and 2, the rolled glass cloth 1 of this embodiment has a core tube 2 in the center, and a long piece of glass cloth 3 is wound around the core tube 2 in the direction of its length. The long piece of glass cloth 3 is woven using glass fibers consisting of multiple glass filaments as warp and weft threads, 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] From the viewpoint of preventing collapse and wavy buckling, the thickness of the long glass cloth 3 is preferably in the range of 8 to 80 μm, and more preferably 9 to 14 μm.

[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. By having the length of the long glass cloth 3 within the above range, the effect of reducing wavy buckling can be sufficiently obtained.

[0018] For the roll-shaped glass cloth 1, in the middle layer 4, 50% of the total length L in the length direction of the long glass cloth 3, i.e., 0.5L, is wound around the core tube 2, and the difference between the maximum value and the minimum value of the 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 2.9 or less. Incidentally, the middle layer 4, in other words, is in a state where 0.5L of the length is unwound from the surface layer 5 in a state where the entire length L in the length direction of the long glass cloth 3 is wound around the core tube 2, as shown by the phantom line in Fig. 2.

[0019] The winding hardness in the middle layer 4 can be measured as follows. First, as shown in Fig. 2, from the direction A of 0° with respect to the vertical direction, a rubber hardness meter (manufactured by Kobunshi Keiki Co., Ltd., product name: Asker rubber hardness meter type C) is pressed against the portion a corresponding to the direction A in the middle layer 4 of the roll-shaped glass cloth 1 to measure the winding hardness in the direction of 0° with respect to the vertical direction. At this time, specifically, in the width direction including the portion a of the roll-shaped glass cloth 1, from a portion 5 cm inside one end in the width direction of the roll-shaped glass cloth 1 to a portion 5 cm inside the other end, the winding hardness of a plurality of portions is measured at intervals of 10 cm, and the average value thereof is taken as the winding hardness in the direction of 0° with respect to the vertical direction.

[0020] Next, the roll-shaped glass cloth 1 is rotated 90° to the left in Fig. 2, and 1 / 4 of the circumference length in the middle layer 4 is unwound, and the portion b corresponding to the direction B in Fig. 2 is moved to the portion corresponding to the portion a, and the same operation as the measurement of the winding hardness in the direction of 0° with respect to the vertical direction is performed to measure the winding hardness in the direction of 90° with respect to the vertical direction.

[0021] Similarly, the roll-shaped glass cloth 1 is further rotated 90° (total 180°) in the left direction in FIG. 2, and unwound by a length of 1 / 4 (total 1 / 2) of the circumference in the middle layer 4, and the part c corresponding to the direction C shown in FIG. 2 is moved to the part corresponding to the part a, and the winding hardness in the direction of 180° with respect to the vertical direction is measured. Then, the roll-shaped glass cloth 1 is further rotated 90° (total 270°) in the left direction in FIG. 2, and unwound by a length of 1 / 4 (total 3 / 4) of the circumference in the middle layer 4, and the part d corresponding to the direction D shown in FIG. 2 is moved to the part corresponding to the part a, and the winding hardness in the direction of 270° with respect to the vertical direction is measured.

[0022] From the viewpoint of further suppressing the occurrence of wavy buckling, the difference between the maximum value and the minimum value of the 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 of the roll-shaped glass cloth 1 is more preferably 1.0 or less.

[0023] Also, for the roll-shaped glass cloth 1, from the viewpoint that the occurrence of unwinding of the roll-shaped glass cloth 1 is unlikely, the average of the winding hardness in each of the directions of 0°, 90°, 180°, and 270° with respect to the vertical direction in the middle layer 4 is preferably in the range of 62.0 or more, more preferably in the range exceeding 70.0, and even more preferably in the range of 71.4 or more. Note that unwinding 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, a slip occurs in the axial direction of the core tube 2 between the layers of the long glass cloth 3 wound, and the end face of the wound roll-shaped glass cloth 1 is deformed into a frustum of a cone.

[0024] Furthermore, the winding hardness of the surface layer 5 of the rolled glass cloth 1, when the entire length L of the long glass cloth 3 is wound around the core tube 2, is preferably in the range of 62.0 or higher, more preferably in the range of 68.4 or higher, even more preferably in the range of over 70.0, and particularly preferably in the range of 71.4 or higher, from the viewpoint of preventing the rolled glass cloth 1 from unraveling. The winding hardness of the surface layer 5 can be determined by measuring the winding hardness in each direction of 0°, 90°, 180°, and 270° with respect to the vertical, by performing the same operation as for measuring the winding hardness of the middle layer 4, when the entire length L of the long glass cloth 3 is wound around the core tube 2, and calculating the average value of the winding hardness in each direction.

[0025] The rolled glass cloth 1 of this embodiment can be manufactured, for example, as follows.

[0026] First, a glass filament is obtained by melting a predetermined glass batch (glass raw material) and fibrousizing it. The filament diameter of the glass filament is not particularly limited, but for printed circuit 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 aforementioned glass filaments are bundled together, for example, in a number ranging from 25 to 500, preferably in the range of 40 to 300, by a method known to the extent that they form glass fibers. The process of melting a glass batch, fibrousizing it to obtain glass filaments, and then bundling multiple of these glass filaments together to obtain glass fibers is called spinning.

[0028] The glass composition of the glass fiber is not particularly limited, but examples include the most common E glass composition, a high-strength, high-modulus glass composition, a high-modulus, 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 aforementioned E glass composition includes SiO2 in the range of 52.0 to 56.0% by mass, Al2O3 in the range of 12.0 to 16.0% by mass, MgO and CaO in total in the range of 20.0 to 25.0% by mass, and B2O3 in the range of 5.0 to 10.0% by mass, relative to the total amount of glass fibers.

[0030] The aforementioned high-strength, high-modulus glass composition is a composition containing SiO2 in the range of 60.0 to 70.0 mass%, Al2O3 in the range of 20.0 to 30.0 mass%, MgO in the range of 5.0 to 15.0 mass%, Fe2O3 in the range of 0 to 1.5 mass%, and Na2O, K2O, and Li2O in total in the range of 0 to 0.2 mass% based on the total amount of glass fibers. Preferably, the aforementioned high-strength, high-modulus glass composition is a composition containing Fe2O3 in the range of 0.15 to 1.50 mass%, ZrO2 in the range of 0.01 to 0.10 mass%, and Na2O, K2O, and Li2O in total in the range of 0.02 to 0.20 mass%.

[0031] The aforementioned high modulus easily manufactured glass composition contains SiO2 in the range of 57.0 to 60.0 mass%, Al2O3 in the range of 17.5 to 20.0 mass%, MgO in the range of 8.5 to 12.0 mass%, CaO in the range of 10.0 to 13.0 mass%, and B2O3 in the range of 0.5 to 1.5 mass%, relative to the total amount of glass fibers, and contains SiO2, Al2O3, MgO, and CaO in a total of 98.0 mass or more.

[0032] The aforementioned low dielectric constant low dielectric loss tangent glass composition contains SiO2 in the range of 48.0 to 62.0 mass%, B2O3 in the range of 17.0 to 26.0 mass%, Al2O3 in the range of 9.0 to 18.0 mass%, CaO in the range of 0.1 to 9.0 mass%, MgO in the range of 0 to 6.0 mass%, Na2O, K2O, and Li2O in total in the range of 0 to 0.5 mass%, TiO2 in the range of 0 to 5.0 mass%, SrO in the range of 0 to 6.0 mass%, F2 and Cl2 in total in the range of 0 to 3.0 mass%, and P2O5 in the range of 0 to 6.0 mass% based on the total amount of glass fibers.

[0033] The aforementioned low thermal expansion, low dielectric constant glass composition may include a composition comprising SiO2 in the range of 42.0 to 63.0 mass% relative to the total amount of glass fibers, Al2O3 in the range of 19.0 to 27.3 mass%, ZnO in the range of more than 3.00 mass% and 13.00 mass% or less, P2O5 in the range of 6.50 to 19.0 mass%, MgO in the range of 0.00 to 7.00 mass%, and Li2O, Na2O, and K2O in a total range of 1.00 mass% or less.

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

[0035] First, the glass cloth is cut to an appropriate size, placed in a platinum crucible, and melted in an electric furnace at a temperature of 1400-1650°C for 6 hours while being stirred, thereby obtaining homogeneous molten glass. If organic matter is attached to the surface of the glass cloth, or if glass fibers are mainly included in the organic matter (resin) as a reinforcing agent, the organic matter is removed by heating in a muffle furnace at 300-650°C for about 2-24 hours before use.

[0036] Next, the obtained molten glass is poured onto a carbon plate to produce glass cullet, which is then crushed and powdered to obtain glass powder. For the light element Li, the glass powder is heated and decomposed with acid, and then quantitatively analyzed using an ICP emission spectrometer. For the other elements, the glass powder is formed into a disc shape using a press, and then quantitatively analyzed using a wavelength-dispersive X-ray fluorescence spectrometer.

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

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

[0039] The elastic modulus of the glass fibers constituting the glass filament is not particularly limited, but is, for example, in the range of 40 to 120 GPa. Conventionally, there is a tendency for winding collapse and wavy buckling to occur easily, so from the viewpoint of more pronounced effects according to the present invention, it 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 filament 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 filament can be measured by the method described in the embodiments below.

[0041] The mass per unit length of the glass fiber is 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 even more 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, from the viewpoint of being less prone to unraveling and wavy buckling.

[0042] Next, a long length of glass cloth 3 can be obtained by weaving the glass fibers as warp or weft threads using a loom that is known in itself. Examples of the loom include jet looms such as air jet or water jet looms, shuttle looms, and rapier looms. Examples of weaving methods using the loom include plain weave, satin weave, twill weave, etc., and plain weave is preferred from the viewpoint of manufacturing efficiency. The weaving density of the glass fiber threads during 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 such sizing agents include those whose film-forming component is starch-based or PVA (polyvinyl alcohol)-based. The sizing agent may also contain oils or softeners.

[0044] The amount of sizing agent attached to the glass cloth is 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] The long glass cloth 3 may be subjected to de-oiling treatment, surface treatment, and fiber opening treatment after weaving.

[0046] As an example of the oil removal treatment, a long piece of glass cloth 3 is placed in a heating furnace at an ambient temperature of 350°C to 400°C for 40 to 80 hours to thermally decompose organic matter attached to the glass fibers.

[0047] The aforementioned surface treatment includes immersing the glass cloth in a silane coupling agent or a solution containing the silane coupling agent and a surfactant, squeezing out excess water, and then heating and drying it at a temperature 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)acrylsilane, phenylsilane, styrylsilane, and isocyanatesilane. In this embodiment, the silane coupling agent may be used alone or in combination of two or more types.

[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 ureidosilanes include γ-ureidopropyltriethoxysilane.

[0051] Examples of chlorosilanes include γ-chloropropyltrimethoxysilane.

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

[0053] Examples of mercaptosilanes 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 (meth)acryloxysilanes include γ-acryloxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

[0056] Examples of phenylsilanes include phenyltrimethoxysilane.

[0057] An example of a styrylsilane is p-styryltrimethoxysilane.

[0058] Examples of isocyanate silanes include γ-isocyanatetopropyltriethoxysilane.

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

[0060] Examples of nonionic surfactants include ethylene oxide propylene oxide alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene-polyoxypropylene-block copolymer, alkyl polyoxyethylene-polyoxypropylene-block copolymer ether, polyoxyethylene fatty acid ester, polyoxyethylene fatty acid monoester, polyoxyethylene fatty acid diester, polyoxyethylene sorbitan fatty acid ester, glycerol fatty acid ester ethylene oxide adduct, polyoxyethylene castor oil ether, hydrogenated castor oil ethylene oxide adduct, alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, glycerol fatty acid ester, polyglycerin fatty acid ester, pentaerythritol fatty acid ester, sorbitol fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyhydric alcohol alkyl ether, fatty acid alkanolamide, acetylene glycol, acetylene alcohol, ethylene oxide adduct of acetylene glycol, and ethylene oxide adduct of acetylene alcohol.

[0061] Examples of cationic surfactants include alkyldimethylbenzylammonium chloride, alkyltrimethylammonium chloride, alkyldimethylethylammonium ethyl sulfate, higher alkylamine salts (such as acetates and hydrochlorides), ethylene oxide adducts to higher alkylamines, condensates of higher fatty acids and polyalkylene polyamines, 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 sulfons, α-olefin sulfons, reaction products of fatty acid halides and N-methyl taurine, 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 alkylaminopropionates, betaine-type amphoteric surfactants such as alkyldimethylbetaine, and imidazoline-type amphoteric surfactants.

[0064] Examples of the fiber-opening process include applying a tension of 20 to 200 N to the warp threads of a long length of glass cloth 3, and then performing fiber-opening by water flow pressure, fiber-opening by high-frequency vibration using a liquid as a medium, fiber-opening by the pressure of a fluid with surface pressure, or fiber-opening by pressing with a roll, thereby widening the yarn width of the warp and weft threads.

[0065] Next, the woven long glass cloth 3 is wound onto the core tube 2 with a predetermined winding tension to obtain a roll of 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 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 at the start of winding. A winding tension of 3 kgf or more at the start of winding increases the average value of the winding hardness and makes it less likely for the winding to collapse, and a winding tension of 60 kgf or less suppresses the occurrence of winding wrinkles due to excessive tension, allowing the long length of glass cloth 3 to be wound up.

[0067] Furthermore, 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 having a winding tension of 3 kgf or more at the end of winding, the average value of the winding hardness can be increased, making it less likely for the winding to collapse, and by having a winding tension of 60 kgf or less, the winding wrinkles caused by excessive tension can be suppressed, allowing the long length of glass cloth 3 to be wound up.

[0068] When winding the long glass cloth 3 onto the core tube 2, the difference between the maximum and minimum winding hardness in the middle layer 4 of the rolled glass cloth 1 in the directions of 0°, 90°, 180°, and 270° with respect to the vertical can be made 2.9 or less by pressing the long glass cloth 3 onto the core tube 2 with multiple press rollers positioned spaced apart from each other so that the winding tension at the beginning and end of the winding is within the aforementioned range.

[0069] By winding the long glass cloth 3 onto the core tube 2 while pressing it with the multiple press rollers described above, localized loosening of the rolled glass cloth 1, which occurs when the press rollers retract as the rolled glass cloth 1 thickens (increases in diameter), is prevented. This reduces the difference between the maximum and minimum values ​​of the winding hardness in the middle layer 4 of the rolled glass cloth 1 in the directions of 0°, 90°, 180°, and 270° with respect to the vertical, making it possible to reduce it to 2.9 or less. If the long glass cloth 3 is wound onto the core tube 2 while pressing it with only one press roller, there is a disadvantage in that localized loosening of the glass cloth 1 on the roll occurs when the press roller retracts as the rolled glass cloth 1 thickens, which can cause wavy buckling.

[0070] When using the aforementioned multiple press rollers, the pressure of each press roller is preferably in the range of 1 to 80 kgf, and more preferably in the range of 2 to 65 kgf. A pressure of 1 kgf or more for each press roller increases the average winding hardness and makes it less likely for the winding to collapse, while a pressure of 80 kgf or less eliminates the problem of wrinkles forming on the surface of the long glass cloth 3 when it is crushed by the press roller while the slack of the long glass cloth 3 has not been eliminated during winding.

[0071] The prepreg of this embodiment includes at least a portion of the long glass cloth 3 that constitutes the roll-shaped glass cloth 1 of this embodiment as described above. The at least portion of the long glass cloth 3 may be glass cloth obtained by unfolding 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 that constitutes the rolled glass cloth 1 of this embodiment with resin using a method known to the extent of the impregnation and semi-curing.

[0073] In the prepreg of this embodiment, the resin impregnated into at least a portion of the long glass cloth 3 is not particularly limited. Examples of such resins include epoxy resin, phenolic 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, fluororesin, and the like.

[0074] The printed circuit board of this embodiment includes at least a portion of the long glass cloth 3 that constitutes the roll-shaped glass cloth 1 of this embodiment described above. The at least portion of the long glass cloth 3 may be glass cloth obtained by unrolling the roll-shaped glass cloth 1 of this embodiment.

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

[0076] Next, examples and comparative examples of the present invention are shown. [Examples]

[0077] [Examples 1-5 and Comparative Example 1] First, glass cloths consisting of glass filaments having the glass composition shown in Table 1, corresponding to the IPC standard cloth type shown in Table 1, were woven. Then, de-oiling treatment, surface treatment, and fiber opening treatment were performed to obtain long glass cloths 3 of Examples 1 to 5 and Comparative Example 1, with a width of 1270 mm and a length of 1000 m.

[0078] Regarding the IPC standard cross-type shown in Table 1, "1078" has 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 This is a glass cloth, and "1010" has the following specifications: 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 This is a glass cloth, and "1006" corresponds to a glass cloth with the following specifications: yarn used: yarn made by bundling 38 glass filaments with a filament diameter of 3.6 μm, warp weave density: 105 threads / 25 mm, weft weave density: 110 threads / 25 mm, thickness: 10 μm.

[0079] Furthermore, the 1006 type glass cloth, which consists of glass filaments of composition A, has a yarn weight of 0.89 g / 1000 m and a mass per unit area of ​​glass cloth of 7.5 g / m². 2 Furthermore, the 1006 type glass cloth, which consists of glass filaments of composition B, has a yarn weight of 0.99 g / 1000 m and a mass per unit area of ​​glass cloth of 8.6 g / m². 2 That was the case.

[0080] Next, the long glass cloths 3 obtained in each example and Comparative Example 1 were processed under the manufacturing conditions shown in Table 1 to obtain the rolled glass cloths 1 of Examples 1 to 5 and Comparative Example 1.

[0081] Next, the winding hardness of the middle layer 4 or surface layer 5 of the rolled glass cloth 1 was measured using the method described below, and the wavy buckling in the width direction of the long glass cloth 3 and the collapse of the rolled 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 rolled glass cloth 1 is indicated as "average," and the wavy buckling is indicated as "wavy."

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

[0083] [Wound hardness in the middle layer] As shown in Figure 2, the winding hardness in the direction 0° to the vertical is measured by pressing a rubber hardness tester (manufactured by Polymer Instruments Co., Ltd., product name: Asker Rubber Hardness Tester Type C) from direction A, which is 0° to the vertical, onto part a in the middle layer 4 of the rolled glass cloth 1 corresponding to direction A. Specifically, in the width direction of the rolled glass cloth 1 including part a, the winding hardness of multiple parts is measured at 10cm intervals, from a point 5cm inward from one end of the rolled glass cloth 1 to a point 5cm inward from the other end, and the average value of these measurements is taken as the winding hardness in the direction 0° to the vertical.

[0084] Next, the rolled glass cloth 1 was rotated 90° to the left in Figure 2, unfolding it by a length of 1 / 4 of the circumference in the middle layer 4. The portion b corresponding to direction B in Figure 2 was moved to the portion corresponding to portion a, and the winding hardness in the direction 90° from the vertical was measured by performing the same operation as for measuring the winding hardness in the direction 0° from the vertical.

[0085] Similarly, the rolled glass cloth 1 was rotated another 90° to the left in the direction shown in Figure 2 (total 180°), and then unfolded by a length of 1 / 4 of the circumference in the middle layer 4 (total 1 / 2). The portion c corresponding to direction C in Figure 2 was moved to the portion corresponding to portion a, and the winding hardness in the direction 180° from the vertical was measured. The rolled glass cloth 1 was then rotated another 90° to the left in the direction shown in Figure 2 (total 270°), and then unfolded by a length of 1 / 4 of the circumference in the middle layer 4 (total 3 / 4). The portion d corresponding to direction D in Figure 2 was moved to the portion corresponding to portion a, and the winding hardness in the direction 270° from the vertical was measured.

[0086] Furthermore, the average value of the winding hardness in the 0°, 90°, 180°, and 270° directions relative to the vertical was taken as the average winding hardness in the middle layer. The difference between the maximum and minimum winding hardness values ​​in each of the 0°, 90°, 180°, and 270° directions relative to the vertical was then calculated from the maximum and minimum winding hardness values ​​in each of these directions.

[0087] In Table 1, the difference between the maximum and minimum values ​​of the winding hardness in the directions of 0°, 90°, 180°, and 270° with respect to the vertical direction is described as "the maximum and minimum difference for 0°, 90°, 180°, and 270°".

[0088] Furthermore, when measuring the winding hardness in the direction 0° to the vertical, the coefficient of variation of the winding hardness values ​​measured at multiple points at 10cm intervals, from 5cm inward from one end of the rolled glass cloth 1 to 5cm inward from the other end, was used as the coefficient of variation of the winding hardness in the weft direction.

[0089] [Surface hardness] As shown by the dashed lines in Figure 2, the winding hardness of the surface layer 5, in which the entire length L of the long glass cloth 3 is wound around the core tube 2, was measured in the same way as the winding hardness measurement of the middle layer 4. This was done by measuring the winding hardness in the 0°, 90°, 180°, and 270° directions relative to the vertical, and the winding hardness of the surface layer 5 was determined by calculating the average value of the winding hardness in each direction.

[0090] Furthermore, when measuring the winding hardness in the direction 0° to the vertical, the coefficient of variation of the winding hardness values ​​measured at multiple points at 10cm intervals, from 5cm inward from one end of the rolled glass cloth 1 to 5cm inward from the other end, was used as the coefficient of variation of the winding hardness in the weft direction.

[0091] [Wavy buckling] While unfolding the rolled glass cloth 1 under a tension of 15 kgf, the appearance of the long glass cloth 3 from the length direction to the width direction was visually observed. If three or more wavy bucklings with a height of 1 cm or more occurred at intervals of 10 cm or less from each other, and these bucklings occurred continuously or intermittently over a length of 3 m or more, it was determined that wavy buckling had occurred.

[0092] At this time, samples were evaluated as follows: "◎" if there was no wave-like buckling along the entire length, or in the range from the surface layer 5 to a section 0.9L relative to the total length L; "〇" if there was no wave-like buckling in the range from the surface layer 5 to a section 0.5L relative to the total length L, but wave-like buckling occurred in the range from a section 0.5L relative to the total length L to a section 0.9L relative to the total length L; and "×" if wave-like buckling occurred in the range from the surface layer 5 to a section 0.5L relative to the total length L.

[0093] [Table 1]

[0094] [Table 2]

[0095] Table 1 shows that, according to the rolled glass cloth 1 of Examples 1 to 5, where the difference between the maximum and minimum values ​​of the winding hardness in each direction of 0°, 90°, 180°, and 270° relative to the vertical is 2.9 or less, when unfolded with a tension of 15 kgf, it is clear that the occurrence of wavy buckling can be prevented in the range from the surface layer 5 to the unfolded portion at a length of 0.5 L relative to the total length L. On the other hand, in the rolled glass cloth 1 of Comparative Example 1, where the difference between the maximum and minimum values ​​of the winding hardness in each direction of 0°, 90°, 180°, and 270° relative to the vertical is greater than 2.9, it is clear that even if the coefficient of variation of the winding hardness in the weft direction is about the same as that of Examples 1 to 5, when unfolded with a tension of 15 kgf, it is clear that the occurrence of wavy buckling cannot be prevented in the range from the surface layer 5 to the unfolded portion at a length of 0.5 L relative to the total length L. [Explanation of Symbols]

[0096] 1... Rolled glass cloth, 2... Core tube, 3... Long length of glass cloth, 4... Middle layer, 5... Surface layer.

Claims

1. A roll of glass cloth in which a long length of glass cloth, consisting of multiple glass filaments as warp and weft threads, is wound around a core tube in the length direction, In the middle layer of the rolled glass cloth, where 50% of the total length of the long glass cloth is wound around the core tube, the difference between the maximum and minimum winding hardness in the directions of 0°, 90°, 180°, and 270° with respect to the vertical is 2.9 or less. A roll-shaped glass cloth characterized in that the strength of the glass fibers constituting the glass filament is in the range of 1.5 to 6.0 GPa.

2. A roll of glass cloth according to claim 1, characterized in that the entire length of the long glass cloth in the longitudinal direction is wound around the core tube, and the winding hardness of the surface layer of the roll of glass cloth is greater than 70.

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

4. A printed circuit board characterized by comprising at least a portion of the long glass cloth constituting the rolled glass cloth according to claim 1 or 2.

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