Glass cloth and manufacturing method of the same

Abstract

To provide a glass cloth having a single fiber diameter of less than 3.0 μm, a thickness of 15 μm or less, a mass of 10 g / m2 or less, and an excellent dielectric loss tangent.SOLUTION: A glass cloth contains 50 mass % or more of SiO2 in the composition. A single fiber diameter of either a warp yarn or a weft yarn constituting the glass cloth is less than 3.0 μm, the thickness of the glass cloth is 15 μm or less, and the mass of the glass cloth is 10 g / m2 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an unprecedented ultrathin and light-weight glass cloth, a manufacturing method thereof, a composite material with an organic resin, and a method for adjusting the single fiber diameter of the glass cloth.The present invention also relates to an ultrathin quartz glass cloth that has excellent dielectric properties by using natural quartz or synthetic quartz as the raw material. [Background technology]

[0002] Currently, with the increasing performance and high-speed communication of information terminals such as smartphones, the printed wiring boards used are becoming increasingly dense and extremely thin, while also achieving lower dielectric constants and lower dielectric loss tangents. A widely used insulating material for these printed wiring boards is a laminate made by laminating prepregs obtained by impregnating glass cloth with a thermosetting resin such as epoxy resin (hereinafter referred to as "matrix resin") and then curing the prepregs under heat and pressure.

[0003] In other words, ultra-thin printed wiring boards require ultra-thin glass cloth. Glass cloth is made by bundling multiple filaments and twisting them into yarn, which is then woven into cloth. In other words, it is important to reduce the diameter of the single filament.

[0004] In Patent Document 1, a glass cloth having a single fiber diameter of 4 μm is obtained, but in order to meet the future demand for thinner glass cloth, a glass cloth having a thinner single fiber diameter is required. Patent Document 2 describes a low-weight glass cloth having a thickness in the range of 7.5 to 12.0 μm and a thickness of 1 m, which is made of filaments having a diameter in the range of 3.0 to 4.2 μm. 2 Glass cloths with masses in the range of 6.0 to 10.0 g per cloth have been reported.

[0005] However, glass filaments with a single fiber diameter of less than 3 μm have very low strength due to their extremely small fiber diameter, and the filaments break and become fluffed during the process of bundling into strands or twisting the strands into yarns, causing problems during warping and making weaving difficult. Furthermore, the yarn itself is very light, which causes various problems, such as the inability to weave the weft straight when weaving with an air jet loom. As described in JIS R3413:2012 (Non-Patent Document 1), glass fibers with a diameter of less than 3 μm are not defined.

[0006] There is also a demand for bonding films for bonding low-surface-roughened copper foil to substrates, and the use of glass cloth in combination is being considered to improve strength and reduce thermal expansion, resulting in a demand for ultra-thin glass cloth. There is also a demand for thinner multilayer substrates, and a prepreg made of ultra-thin glass cloth and organic resin is desired. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-117169 [Patent Document 2] Patent No. 6818278 [Non-patent literature]

[0008] [Non-Patent Document 1] JIS R 3413:2012 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above problems, and provides a fiber optic cable having a single fiber diameter of less than 3.0 μm, a thickness of 15 μm or less, and a mass of 10 g / m 2 Below, the air permeability is 50 (cm 3 / cm 2 / s) or more and has an excellent dielectric loss tangent. [Means for solving the problem]

[0010] As a result of intensive research into achieving the above object, the present inventors have found that by weaving glass cloth from glass filaments and then reducing the fiber diameter by etching, it is possible to obtain a glass cloth having a single fiber diameter of less than 3 μm and a thickness of 15 μm or less while avoiding problems that may occur during weaving, and have thus completed the present invention.

[0011] Therefore, the present invention provides the following inventions. 1. A glass cloth containing 50% by mass or more of SiO2 in its composition, in which the single fiber diameter of either the warp or weft constituting the glass cloth is less than 3.0 μm, the thickness of the glass cloth is 15 μm or less, and the mass is 10 g / m 2 The following is glass cloth. 2. The glass cloth according to 1, wherein the total content of SiO2 and B2O3 contained in the composition is 65 mass% or more. 3. The glass cloth according to 1 or 2, wherein the SiO2 content in the composition is 95 mass % or more and the thickness of the glass cloth is 10 μm or less. 4. Air permeability is 50 (cm 3 / cm 2 / s) or more glass cloth. 5. A method for producing the glass cloth according to any one of 1 to 3, comprising an etching step of treating the glass cloth with one or more etching solutions selected from a hydrofluoric acid aqueous solution, an ammonium fluoride aqueous solution, a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, a sodium carbonate aqueous solution, ammonia water, and alkaline electrolyzed water. 6. A method for adjusting the single fiber diameter of glass cloth, which comprises treating glass cloth with one or more etching solutions selected from hydrofluoric acid aqueous solution, ammonium fluoride aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, ammonia water, and alkaline electrolytic water, and etching the single fiber diameter of the glass cloth to 0.1 μm or more. 7. The method for adjusting the single fiber diameter of glass cloth according to 6, wherein the etching solution is alkaline electrolyzed water having a pH of 12 or more. 8. The method for adjusting the single fiber diameter according to 6 or 7, wherein glass cloth having a single fiber diameter of 3.0 μm or more is etched with an etching solution to adjust the single fiber diameter to less than 3.0 μm. 9. A composite material comprising the glass cloth according to any one of 1 to 3 and an organic resin. [Effects of the Invention]

[0012] According to the present invention, the technical problems in the spinning, twisting and weaving processes caused by glass filaments with extremely fine single fiber diameters can be solved, and the single fiber diameter is less than 3.0 μm, the thickness is 15 μm or less, and the mass is 10 g / m 2 Below, the air permeability is 50 (cm 3 / cm 2 This glass cloth has the remarkable effect of being compatible with the multilayer substrates used in the increasing number of high-speed communications such as 5G, and of being able to reduce transmission loss. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below. [Glass components] The glass used for the glass cloth of the present invention contains 50% or more by mass of SiO2 in its composition. If the SiO2 content is less than 50% by mass, other metal components will become the main components of the glass cloth during the etching process described below, resulting in uneven dissolution, which will lead to variations in the single fiber diameter and brittleness of the glass cloth. From the viewpoints of electrical properties such as dielectric loss tangent and physical properties such as thermal expansion, a quartz glass cloth with an SiO2 content of 95% by mass or more is preferred, and 98% by mass or more is more preferred. Examples of other metal components include B2O3, Al2O3, MgO, CaO, ZnO, Fe2O3, Li2O, TiO2, Na2O, SrO, Cr2O3, As2O3, Sb2O3, P2O5, ZrO2, Cl2, SO3, and MoO2. Any proportion may be used as long as the glass cloth can be produced. Furthermore, since the dielectric properties can be improved by increasing the contents of SiO2 and B2O3, the total content of SiO2 and B2O3 is preferably 65 mass% or more, more preferably 70 mass% or more, and the SiO2 content is even more preferably 95 mass% or more.

[0014] [Glass cloth] The single fiber diameter of either the warp or weft threads constituting the glass cloth is less than 3.0 μm, preferably 0.1 to 2.9 μm, and more preferably 0.5 to 2.5 μm. It is preferable that both the warp and weft threads have the above single fiber diameter. By making the diameter 0.1 μm or more, it is possible to obtain better effects of improving the dielectric properties and strength, and reducing thermal expansion in a film combined with an organic resin. The single fiber diameter is the average value of 10 single fiber measurements taken under a microscope.

[0015] The thickness of the glass cloth is 15 μm or less, preferably 10 μm or less. There is no particular lower limit and it is appropriately selected from, for example, 0.5 μm or more. The thickness of the glass cloth is measured according to the method for measuring the thickness of cloth and mat of JIS R 3420.

[0016] The mass of the glass cloth is 10 g / m 2 less than 8 g / m 2 The lower limit is not particularly limited, and is, for example, 0.3 g / m or less.2 The mass of the glass cloth is measured in accordance with the method for measuring the mass of cloth and mat in JIS R 3420. The air permeability (cm 3 / cm 2 / s) is preferably 50 or more, more preferably 100 or more. There is no particular upper limit and it is appropriately selected, for example, from 500 or less. The air permeability of the glass cloth is measured in accordance with the method for measuring the air permeability of cloth specified in JIS R 3420.

[0017] The dielectric loss tangent of the glass cloth at 10 GHz is preferably less than 0.0070, more preferably 0.0020 or less, and even more preferably 0.0010 or less. The dielectric loss tangent is measured by a resonance method, specifically as described in the Examples below. Furthermore, a silane coupling agent may be attached to the surface of the glass cloth, as will be described in the description of the manufacturing method.

[0018] [Glass cloth manufacturing method] The method for producing the glass cloth of the present invention is not particularly limited, but may include, for example, a method including a step of etching the glass cloth.

[0019] [Glass cloth before etching] The method for producing the glass cloth before etching is not particularly limited, but a suitable method is to produce glass filaments, bundle them into strands, twist them to produce yarns, and weave the yarns into glass cloth using a weaving machine.

[0020] The method for producing the glass filament is not particularly limited, but examples include a method in which an ingot of a specified glass composition is heated and drawn, and a method in which the ingot is melted to form molten glass and then formed into a filament using a bushing. In particular, when the proportion of SiO2 is 95 mass% or more, the melting temperature becomes high, making drawing using a bushing difficult, and heating and drawing using an oxyhydrogen burner is preferred.

[0021] Glass strands can be formed by applying a sizing agent to the surface of glass filaments and bundling them. Glass yarns can be obtained by twisting the resulting glass strands. The twisting frequency is preferably 0.1 to 5.0 times per 25 mm.

[0022] The glass cloth can be produced by weaving glass yarn. When producing a thin glass cloth, the glass cloth of the present invention has a mass of 5 to 50 g / m before etching. 2 is preferred, and in order to reduce the amount of etching afterwards, 5 to 25 g / m 2 The weaving method is not particularly limited, and examples thereof include weaving methods using an air jet loom, a water jet loom, a rapier loom, a shuttle loom, etc. When weaving using an air jet loom or the like, polyvinyl alcohol or starch can be applied as a secondary sizing agent to further improve lubricity.

[0023] The single fiber diameter of the glass cloth before etching is preferably 3.0 μm or more, more preferably 3.5 μm or more. It can also be more than 10 μm, 11 to 25 μm. If the single fiber diameter is too large or the glass cloth is too thick, a large amount is required for etching, which is unsuitable from the viewpoint of productivity.

[0024] [Glass cloth etching] Etching quartz glass cloth with a sizing agent attached thereto after weaving allows for adjustment of the single fiber diameter while suppressing the generation of fluff, and also makes it possible to remove the sizing agent. The etching solution for adjusting the single fiber diameter is not particularly limited, but may include one or more selected from the group consisting of an aqueous solution of hydrofluoric acid, an aqueous solution of ammonium acid fluoride (NHF HF), an aqueous solution of potassium acid fluoride (KHF), and other acidic aqueous solutions, an aqueous solution of ammonium fluoride, an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, an aqueous solution of sodium carbonate, aqueous ammonia, and alkaline electrolyzed water. Of these, alkaline electrolyzed water with a pH of 12.0 or higher (measured at 25°C) is preferred from the viewpoints of the working environment and wastewater treatment.

[0025] The etching conditions for the glass cloth are not particularly limited as long as the monofilament diameter can be adjusted. However, a temperature of room temperature (23°C) to 100°C is preferred, with 40 to 80°C being more preferred. If the temperature is below room temperature, the etching process may proceed slowly. If the treatment temperature exceeds 100°C, it may be difficult to adjust the etching amount. The treatment time is adjusted depending on the treatment temperature and the desired monofilament diameter. For example, a treatment condition of 60°C can reduce the silica glass fiber diameter by approximately 0.035 μm per hour. In particular, within the range of 40 to 80°C, 3 to 100 hours is preferred, 12 to 80 hours is more preferred, and 25 to 72 hours is even more preferred. After the desired monofilament diameter is achieved, the glass cloth may be washed with pure water or ion-exchanged water until the pH of the washing solution reaches 7, after which the water adhering to the glass cloth is heated and dried. The washing method is not particularly limited, but examples include immersion in washing water and spraying with washing water. When immersing, stress such as ultrasonic waves may be applied. The drying method is not particularly limited, but examples thereof include hot air drying, infrared drying, and drying with a hot roll.

[0026] [Glass cloth opening] Glass cloth can be opened by etching. The opening method used to obtain a desired degree of opening is not particularly limited, but examples include an opening method using ultrasonic waves, a method using a high-pressure columnar water flow, and a method using a diffusion spray in the atmosphere. A method using a gas-liquid mixed mist with an adjusted air-water volume ratio is particularly suitable, as it allows efficient opening while suppressing strand misalignment and fuzzing. Furthermore, since fuzzing is also removed by the etching treatment, a cloth without fuzz can be produced. The timing of opening is not particularly limited, but it is preferable to perform it before removing the sizing agent, as this makes use of the slipperiness of the sizing agent. Furthermore, since the sizing agent is removed during etching, filaments are more likely to separate from each other, resulting in greater opening. With such an opening method, it is possible to increase the air permeability of a thin glass cloth to 300 cm 3 / cm 2 / s or less. The air permeability is 30 cm 3 / cm 2 / s or more is preferable, 50cm 3 / cm2 / s or more is preferable, 50 to 280 cm 3 / cm 2 The air permeability is measured in accordance with the method for measuring the air permeability of cloth specified in JIS R 3420.

[0027] [Silane treatment of glass cloth] After the sizing agent has been removed, the glass cloth can be used as is, or it can be treated with silane to become silane-treated glass cloth. In particular, glass cloth from which the sizing agent has been removed by long-term etching is prone to localized generation of SiOH groups on the surface after etching, since the etching reaction is Si-O-Si + OH- → SiOH + SiO-, which breaks the Si-O-Si bond. Therefore, by reacting the SiOH groups locally generated on the surface with a silane coupling agent, it is possible to lower the dielectric tangent and increase the strength.

[0028] Examples of the silane coupling agent include, but are not limited to, trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenylmethylvinylethoxysilane, naphthyltrimethoxysilane, naphthyltriethoxysilane, 1,4-bis(methoxydimethylsilyl)benzene, tetramethicone, methylmethylvinylethoxysilane ... Dimethoxysilane, tetraethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-Epoxycyclohexyl)ethylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl Examples of alkoxysilane compounds include N-(2-(aminoethyl)-3-aminopropyltrimethoxysilane and its hydrochloride, N-(vinylbenzyl)-2-aminoethyl-3-aminopropylmethyldimethoxysilane and its hydrochloride, 3-isocyanatepropyltriethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and bis(trisethoxysilylpropyl)tetrasulfide. These may be used alone or in combination of two or more. Among these, preferred are 3-aminopropyltrimethoxysilane, N-(2-(aminoethyl)-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane.

[0029] The silane treatment method is not particularly limited, but examples include a method in which glass fibers are impregnated with an aqueous solution containing a silane coupling agent, and a treatment using roll coating. A preferred silane treatment method for thin glass cloth, such as that of the present invention, involves adding a silane coupling agent to the etching solution after the target single fiber diameter has been achieved by the etching treatment. The silane coupling agent is preferably added in an amount such that the silane coupling agent adheres to the glass cloth surface after silane treatment at 0.01 to 1 mass%. For example, it is preferably added at a concentration of 0.01 to 1 mass% relative to the etching solution. By maintaining the silane coupling agent adhered to the glass cloth surface at 0.01% or more, it sufficiently reacts with the SiOH groups on the surface, resulting in a lower dielectric loss tangent. On the other hand, by maintaining the silane coupling agent adhered to the glass cloth surface at 1 mass% or less, excessive adhesion of the silane coupling agent to the glass cloth surface is suppressed, maintaining the flexibility of the glass cloth and further reducing the dielectric loss tangent. The treatment temperature is not particularly limited, but in order for the silane coupling agent to quickly hydrolyze and react with the surface of the quartz glass cloth, a temperature of 40 to 80° C. The treatment time is not particularly limited as long as the treatment is performed for a time such that the silane coupling agent adheres to the surface of the glass cloth after the silane treatment in an amount of, for example, 0.01 to 1 mass %, but 0.5 to 2 hours is preferred.

[0030] After the silane treatment, the glass cloth is washed with pure water or ion-exchanged water until the pH of the washing solution reaches, preferably, 7, and then the water adhering to the glass cloth is dried by heating. During this process, excess silane coupling agent that has not reacted with the glass cloth and is physically adsorbed is removed.

[0031] [Method for preparing the single fiber diameter of glass cloth] The present invention provides a method for adjusting the single fiber diameter of glass cloth, which comprises treating glass cloth with one or more etching solutions selected from a hydrofluoric acid aqueous solution, an ammonium fluoride aqueous solution, a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, a sodium carbonate aqueous solution, an ammonia solution, and an alkaline electrolytic water, thereby etching the single fiber diameter to 0.1 μm or more. The etching method is the same as the manufacturing method described above. The treatment temperature and treatment time are adjusted depending on the target single fiber diameter. The single fiber diameter etched by the etching treatment is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1.0 μm or more. There is no particular upper limit, and it can be appropriately selected from 10 μm or less.

[0032] The etching method is the same as the method described above, and the etching solution used is preferably alkaline electrolyzed water with a pH of 12 or higher. In particular, it is preferable to etch glass cloth having a single fiber diameter of 3.0 μm or more with the etching solution to adjust the single fiber diameter to less than 3.0 μm. The single fiber diameter after etching is more preferably 0.1 to 2.9 μm, and even more preferably 0.5 to 2.5 μm.

[0033] [Composite material (film)] The glass cloth of the present invention has an excellent dielectric loss tangent, a small single fiber diameter of the glass cloth, high breathability, and a small thickness, and therefore can be used to obtain a thin film impregnated with an organic resin. The film of the present invention is particularly suitable as an adhesive film with excellent dielectric loss tangent, since the glass cloth provides the effects of improving film strength and reducing the coefficient of thermal expansion. By laminating multiple layers of this adhesive film (prepreg), it is possible to produce a very thin substrate.

[0034] The organic resin is not particularly limited, and examples thereof include cyanate ester resins, bismaleimide cyanate ester resins, epoxy resins, polyfunctional maleimide resins, and unsaturated group-containing polyphenylene ether resins, and these can be used alone or in combination of two or more. The amount of the organic resin used is within a known range. [Example]

[0035] EXAMPLES The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0036] [Preparation example of sizing agent for quartz glass fibers] 1. Primary sizing agent: A primary sizing agent for quartz glass fibers was prepared, consisting of 3.0 mass % starch, 0.5 mass % beef tallow, 0.1 mass % emulsifier Emulmin (manufactured by Sanyo Chemical Industries, Ltd.), and the remainder water. 2. Secondary sizing agent: An aqueous solution containing 1.5% by mass of polyvinyl alcohol, 1.5% by mass of starch, and the remainder water was prepared.

[0037] [Example of glass cloth preparation] 1. Glass cloth A: A glass ingot containing 53% by mass of SiO2, 8% by mass of B2O3, 15% by mass of Al2O3, 21% by mass of CaO, 2% by mass of MgO, and 1% by mass each of Na2O and KO was heated and drawn to produce glass fibers consisting of glass filaments with a diameter of 4 μm. The above-mentioned glass fiber primary sizing agent was applied with an applicator, and then the fibers were bundled with a bundler and wound up to produce a glass strand containing 100 silica glass filaments. The wound glass strand was twisted at 24 T / m to produce a glass yarn. A secondary sizing agent was applied to the obtained glass yarn, and then a glass cloth was produced using an air jet loom at a weave density conforming to IPC standard 1027. The obtained glass cloth with the sizing agent attached was subjected to an opening treatment using a PSN slit nozzle manufactured by Ikeuchi Co., Ltd., using tap water at 25°C and 0.3 MPa and air compressed to 0.3 MPa, so that the air-water volume ratio was V2 / V1 = 35. The glass cloth obtained above was designated as glass cloth A.

[0038] 2. Glass cloth B: Glass fibers composed of glass filaments with a diameter of 4 μm were prepared in the same manner as for glass cloth A, except that the raw glass composition was changed to 55 mass% SiO2, 15 mass% B2O3, 15 mass% Al2O3, 12 mass% CaO, 2 mass% MgO, and 1 mass% Na2O and K2O. A glass cloth was woven at a weave density in accordance with IPC Standard 1027 and subjected to an opening treatment. The obtained glass cloth was named glass cloth B.

[0039] 3. Glass cloth C: Glass fibers consisting of glass filaments with a diameter of 4 μm were prepared in the same manner as for glass cloth A, except that a silica glass ingot containing 99.9% by mass of SiO2 was used. A glass cloth was woven at a weave density in accordance with IPC standard 1027 and subjected to an opening treatment. The obtained glass cloth was designated glass cloth C.

[0040] 4. Glass cloth D: A quartz glass ingot containing 99.9% by mass of SiO2 was used to prepare a filament having a diameter of 3.6 μm. Thirty-eight of the obtained filaments were bundled together to form a quartz yarn in the same manner as for glass cloth A, and the yarn was woven to produce a glass cloth with a weave density conforming to IPC standard 1006. The obtained glass cloth was designated glass cloth D.

[0041] 5. Glass cloth E: For comparison Glass fibers composed of glass filaments with a diameter of 4 μm were prepared in the same manner as for glass cloth A, except that the raw glass composition was changed to 40 mass% SiO2, 8 mass% B2O3, 22 mass% Al2O3, 27 mass% CaO, 2 mass% MgO, and 1 mass% each of Na2O and K2O. A glass cloth was woven at a weave density in accordance with IPC Standard 1027 and subjected to an opening treatment. The obtained glass cloth was designated glass cloth E.

[0042] 6. Glass cloth F: For comparison A 2.5 μm diameter filament was produced using a quartz glass ingot containing 99.9% SiO2 by mass. 100 of the resulting filaments were bundled together to produce a quartz yarn in the same manner as for glass cloth D, but frequent thread breakage occurred, resulting in a low yarn yield. This yarn was woven to produce a glass cloth with a weave density conforming to IPC standard 1006. The resulting glass cloth had broken fibers and uneven basket holes during the opening process, making it impossible to obtain a glass cloth. The physical properties of the prepared glass cloth are shown in Table 1.

[0043] [Table 1]

[0044] [Example 1] Glass cloth A was placed in an alkali-resistant etching bath, and alkaline electrolyzed water S-2665 (pH 12, measured at 25°C) manufactured by Suzuki Oil & Fat Industries Co., Ltd. was poured into the bath until the glass cloth was completely submerged. The bath was then sealed and left to stand at 60°C for 72 hours for etching. 3-Methacrylpropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) was then added at 0.2% by mass to the alkaline electrolyzed water, and the treatment was continued at 60°C for 1 hour. The alkaline electrolyzed water was then drained from the etching bath and replaced with ion-exchanged water until the pH reached 7 (three times), and the quartz glass cloth was washed. The washed etching cloth was then dried at 110°C for 10 minutes in a Yamato Co., Ltd. DKN602 constant temperature incubator with a blower. Table 2 shows the single fiber diameter, cloth thickness, mass and air permeability of the etched glass cloth A.

[0045] [Example 2] Glass cloth B was placed in an alkali-resistant etching tank, and subjected to etching and coupling treatment simultaneously in the same manner as in Example 1, and then washed and dried. Table 2 shows the single fiber diameter, cloth thickness, mass and air permeability of the etched glass cloth B.

[0046] [Example 3] Glass cloth C was placed in an alkali-resistant etching tank, and subjected to etching and coupling treatment simultaneously in the same manner as in Example 1, and then washed and dried. Table 2 shows the single fiber diameter, cloth thickness, mass, and air permeability of the etched glass cloth C.

[0047] [Example 4] The glass cloth C was placed in an alkali-resistant etching bath, and the treatment was carried out in the same manner as in Example 3, except that the etching time was changed to 31 hours. Table 2 shows the single fiber diameter, cloth thickness, mass, and air permeability of the etched glass cloth C.

[0048] [Example 5] The glass cloth C was placed in an alkali-resistant etching bath, and the treatment was carried out in the same manner as in Example 3, except that the etching time was changed to 100 hours. Table 2 shows the single fiber diameter, cloth thickness, mass, and air permeability of the etched glass cloth C.

[0049] [Example 6] Glass cloth C was placed in an alkali-resistant etching bath and treated in the same manner as in Example 3, except that the etching temperature was changed to 80° C. and the etching time was changed to 100 hours. Table 3 shows the single fiber diameter, cloth thickness, mass and air permeability of the etched glass cloth C.

[0050] [Example 7] Glass cloth D was placed in an alkali-resistant etching bath and treated in the same manner as in Example 1, except that the etching temperature was changed to 60° C. and the etching time was changed to 60 hours. Table 3 shows the single fiber diameter, cloth thickness, mass and air permeability of the etched glass cloth D.

[0051] [Comparative Example 1] Glass cloth C was placed in an alkali-resistant etching bath and treated in the same manner as in Example 3, except that the etching temperature was changed to 60° C. and the etching time was changed to 10 hours. Table 3 shows the single fiber diameter, cloth thickness, mass and air permeability of the etched glass cloth C.

[0052] Comparative Example 2 Glass cloth C was placed in an alkali-resistant etching bath and treated in the same manner as in Example 3, except that the etching temperature was changed to 10° C. and the etching time was changed to 110 hours. Table 3 shows the single fiber diameter, cloth thickness, mass and air permeability of the etched glass cloth C.

[0053] Comparative Example 3 The glass cloth E was placed in an alkali-resistant etching bath and treated in the same manner as in Example 1, except that the etching temperature was changed to 60° C. and the etching time was changed to 31 hours. Table 3 shows the single fiber diameter, cloth thickness, mass, and air permeability of the etched glass cloth E.

[0054] The glass cloth obtained above was evaluated by the following methods, and the results are shown in Tables 2 and 3 below. 1. Measurement of Single Fiber Diameter The glass cloth was fixed vertically using room temperature curing epoxy resin NER-814 manufactured by Nissin EM Co., Ltd., and the surface was polished. The diameter of the quartz glass filament was measured at 10 points using a scanning electron microscope JSM-IT700HR InTouchScope manufactured by JEOL Ltd., and the average was taken as the single fiber diameter. 2. Thickness measurement The thickness was measured according to the method for measuring the thickness of cloth and mats specified in JIS R3420. 3. Measurement of basis weight The measurement was carried out in accordance with the method for measuring the mass of cloth and mats specified in JIS R3420. 4. Measurement of air permeability Measurement was carried out in accordance with the method for measuring breathability of cloth specified in JIS R3420. 5. Silane coupling agent adhesion amount (loss on ignition) The moisture content and loss on ignition were measured according to the method for measuring moisture content and loss on ignition specified in JIS R3420. 6. Measurement of dielectric loss tangent The dielectric loss tangent of the glass cloth at 10 GHz was measured using a cavity resonator (TE011 mode) manufactured by AET Corporation. The thickness of the glass cloth was measured using the theoretical film thickness, which is Theoretical film thickness t (μm) = mass (g / m 2 ) / specific gravity (g / cm 3 ) was calculated from

[0055] [Table 2]

[0056] [Table 3]

[0057] From Tables 2 and 3, if the method of the present invention is used, the single fiber diameter is less than 3.0 μm, the thickness of the glass cloth is 15 μm or less, and the mass is 10 g / m 2 The following quartz glass cloth was obtained. Conventionally, filaments with a single fiber diameter of less than 3.0 μm were difficult to mass-produce, even if test prototypes were possible.

[0058] According to the present invention, by adjusting the single fiber diameter of conventional glass cloth by etching, it is possible to obtain thin quartz glass cloth with a single fiber diameter of 3.0 μm or less, which has not been possible to weave until now. This has the significant effect of enabling the integration of substrates used in high-speed communications such as 5G, which will become increasingly common, and reducing transmission loss. In particular, thin glass cloth is expected to be used to reinforce adhesive films with low-roughening copper clad.

[0059] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention.

Claims

1. SiO in the composition 2 A glass cloth containing 50% by mass or more of the above, wherein the diameter of a single fiber of either the warp or weft constituting the glass cloth is less than 3.0 μm, the thickness of the glass cloth is 15 μm or less, and the mass is 10 g / m 2 The glass cloth is as follows.

2. SiO contained in the composition 2 and B 2 O 3 2. The glass cloth according to claim 1, wherein the total content of said glass fibers and said glass fibers is 65% by mass or more.

3. SiO contained in the composition 2 2. The glass cloth according to claim 1, wherein the content of the polyisocyanate is 95% by mass or more and the thickness of the glass cloth is 10 μm or less.

4. The air permeability is 50 (cm 3 / cm 2 / s) or more glass cloth.

5. 4. A method for producing the glass cloth according to claim 1, comprising an etching step of treating the glass cloth with one or more etching solutions selected from the group consisting of an aqueous hydrofluoric acid solution, an aqueous ammonium fluoride solution, an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, an aqueous sodium carbonate solution, aqueous ammonia, and alkaline electrolyzed water.

6. A method for adjusting the single fiber diameter of a glass cloth, comprising treating the glass cloth with one or more etching solutions selected from a hydrofluoric acid aqueous solution, an ammonium fluoride aqueous solution, a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, a sodium carbonate aqueous solution, an ammonia water, and an alkaline electrolyzed water, thereby etching the single fiber diameter of the glass cloth to 0.1 μm or more.

7. 7. The method for adjusting the diameter of a single fiber of glass cloth according to claim 6, wherein the etching solution is alkaline electrolyzed water having a pH of 12 or more.

8. 8. The method for adjusting the single fiber diameter according to claim 6 or 7, wherein glass cloth having a single fiber diameter of 3.0 μm or more is etched with an etching solution to adjust the single fiber diameter to less than 3.0 μm.

9. A composite material comprising the glass cloth according to any one of claims 1 to 3 and an organic resin.

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