Glass cloth and manufacturing method thereof

Abstract

Provided is a glass cloth having a single fiber diameter of less than 3.0 [mu] m, a thickness of 15 [mu] m or less, a mass of 10 g / m2 or less, and an excellent dielectric loss tangent. The glass cloth contains 50% by mass or more of SiO2 in the composition, the single fiber diameter of either warp or weft constituting the glass cloth is less than 3.0 [mu] m, the thickness of the glass cloth is 15 [mu] m or less, and the mass of the glass cloth is 10 g / m2 or less.

Description

Technical Field

[0001] This invention relates to an ultra-thin and lightweight glass cloth, not previously available, and its manufacturing method, as well as composite materials thereof with organic resins, and a method for adjusting the single fiber diameter of the glass cloth. Furthermore, it relates to an ultra-thin quartz glass cloth with excellent dielectric properties obtained by using natural quartz or synthetic quartz as raw materials. Background Technology

[0002] Currently, with the increasing performance and high-speed communication of information terminals such as smartphones, the printed circuit boards (PCBs) used are becoming increasingly dense and extremely thin, while also exhibiting significant improvements in dielectric strength and dielectric loss tangent. As the insulating material for these PCBs, laminates are widely used, which are obtained by impregnating glass cloth in thermosetting resins such as epoxy resin (hereinafter referred to as "matrix resin"), followed by heating and pressure curing.

[0003] In other words, the ultra-thinning of printed circuit boards necessitates the ultra-thinning of glass cloth. Glass cloth is made by bundling multiple long filaments, twisting them into yarn, and then weaving them into fabric. Therefore, reducing the diameter of individual fibers in the filaments is crucial.

[0004] Patent Document 1 describes a glass cloth with a single fiber diameter of 4 μm. For future applications requiring thinner glass cloth, even finer single fiber diameters are needed. Patent Document 2 reports a low-weight glass cloth composed of filaments with diameters ranging from 3.0 to 4.2 μm, exhibiting a thickness ranging from 7.5 to 12.0 μm and a thickness per 1 m... 2 Glass cloth with a mass ranging from 6.0 to 10.0 g.

[0005] However, glass filaments with a single fiber diameter of less than 3 μm are extremely weak due to their thinness. During the processes of bundling the filaments into bundles and twisting them into yarn, the filaments break into fluff, causing problems during warping and making weaving difficult. Furthermore, because the yarn itself is very light, various problems arise when using an air-jet loom, such as the inability to straighten the weft threads. As described in JIS R3413:2012 (Non-Patent Document 1), glass fibers smaller than 3 μm have not yet been defined.

[0006] In addition, there is a demand for bonding films for adhering copper foil with low surface roughness to substrates. To improve strength and reduce thermal expansion, the use of glass cloth has been studied, and there is a demand for ultra-thin glass cloth. Furthermore, there is a demand for thinner multilayer substrates, and there is a desire for prepregs composed of ultra-thin glass cloth and organic resin.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 6818278

[0010] Non-patent literature

[0011] Non-patent literature 1: JIS R 3413:2012 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] This invention was made in view of the above-mentioned problems, and its purpose is to provide a single fiber with a diameter of less than 3.0 μm, a thickness of less than 15 μm, and a mass of 10 g / m³. 2 The following has an air permeability of 50 (cm). 3 / cm 2 Glass cloth with a dielectric loss tangent of ≥ / s and excellent dielectric loss angle.

[0014] Methods for solving problems

[0015] In order to achieve the above objectives, the inventors conducted in-depth research and found that after glass cloth is woven from glass filaments, etching makes the fiber diameter thinner, thereby avoiding the problems during weaving and obtaining glass cloth with a single fiber diameter of less than 3μm and a thickness of less than 15μm, thus completing the present invention.

[0016] Therefore, the present invention provides the following invention.

[0017] 1. Glass cloth, comprising a composition of more than 50% by mass SiO2, wherein the diameter of any single fiber of either the warp or weft of the glass cloth is less than 3.0 μm, the thickness of the glass cloth is less than 15 μm, and the mass is 10 g / m³. 2 the following.

[0018] 2. The glass cloth according to claim 1, wherein the total content of SiO2 and B2O3 contained in the composition is 65% by mass or more.

[0019] 3. The glass cloth according to 1 or 2, wherein the SiO2 contained in the composition is 95% by mass or more, and the thickness of the glass cloth is less than 10 μm.

[0020] 4. The glass cloth according to any one of 1 to 3, wherein the air permeability is 50 (cm²). 3 / cm 2 / s) and above.

[0021] 5. A method for manufacturing glass cloth according to any one of 1 to 4, comprising an etching step of treating the glass cloth with an etching solution selected from one or more of aqueous hydrofluoric acid solution, aqueous ammonium fluoride solution, aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, aqueous sodium carbonate solution, ammonia solution, and alkaline electrolyzed water.

[0022] 6. A method for adjusting the diameter of a single fiber of glass cloth, wherein the glass cloth is treated with an etching solution selected from one or more of hydrofluoric acid aqueous solution, ammonium fluoride aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, ammonia water and alkaline electrolyzed water to etch away more than 0.1 μm of the diameter of the single fiber of the glass cloth.

[0023] 7. The method for adjusting the single fiber diameter of the glass cloth according to 6, wherein the etching solution is alkaline electrolyzed water with a pH of 12 or higher.

[0024] 8. The method for adjusting the diameter of a single fiber according to 6 or 7, wherein a glass cloth with 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.

[0025] 9. A composite material comprising glass cloth and organic resin according to any one of 1 to 4.

[0026] The effects of the invention

[0027] According to the present invention, the technical problems in the spinning, twisting and weaving processes of glass filaments with extremely fine single fiber diameters can be solved, thus providing a single fiber diameter of less than 3.0 μm, a thickness of less than 15 μm, and a mass of 10 g / m³. 2 The following has an air permeability of 50 (cm). 3 / cm 2 A glass cloth with a dielectric loss tangent of 1000 m / s or higher is provided. This glass cloth achieves significant effects in addressing the multilayering of substrates used in future high-speed communications such as 5G and in suppressing transmission losses. Detailed Implementation

[0028] The present invention will now be described in detail.

[0029] [Glass Composition]

[0030] The glass used in the glass cloth of the present invention contains 50% by mass or more SiO2 in its composition. If the SiO2 content is less than 50% by mass, other metal components become the main components of the glass cloth in the etching process described later, resulting in uneven dissolution and fluctuations in the diameter of individual fibers, thus exhibiting brittleness of the glass cloth. From the perspective of physical properties such as dielectric loss tangent and thermal expansion, a quartz glass cloth with a SiO2 content of 95% by mass or more is preferred, and more preferably 98% by mass or more. Other metal components can be listed as B2O3, Al2O3, MgO, CaO, ZnO, Fe2O3, Li2O, TiO2, Na2O, SrO, Cr2O3, As2O3, Sb2O3, P2O5, ZrO2, Cl2, SO3, MoO2, etc., and can be in any proportion within the range that can be used to manufacture glass cloth. Furthermore, by increasing the content of SiO2 and B2O3, the dielectric properties can be improved. Therefore, the total content of SiO2 and B2O3 is preferably 65% ​​by mass or more, more preferably 70% by mass or more, and even more preferably the content of SiO2 is 95% by mass or more.

[0031] [Glass cloth]

[0032] The diameter of any of the warp and 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. Furthermore, it is preferable that both the warp and weft threads have the aforementioned single fiber diameter. By making it 0.1 μm or more, the dielectric properties and strength of the film combined with the organic resin can be improved, and further, the effect of reduced thermal expansion can be achieved. Furthermore, the single fiber diameter is an average value measured at 10 points on a single fiber using a microscope.

[0033] The thickness of the glass cloth is 15 μm or less, preferably 10 μm or less. There is no particular limitation on the lower limit; for example, it can be appropriately selected from 0.5 μm or more. It should be noted that the thickness of the glass cloth is determined according to the method for determining the thickness of cloth and felt in JIS R 3420.

[0034] The mass of the glass cloth is 10g / m. 2 The following is preferred: 8g / m 2 The following does not specify a lower limit, for example, from 0.3 g / m³. 2 Choose appropriately from the above. It should be noted that the quality of the glass cloth is determined according to the JIS R 3420 method for determining the quality of cloth and felt. The air permeability of the glass cloth (cm²) is... 3 / cm 2 / s) Preferably 50 (cm) 3 / cm 2 / s) or more, more preferably 100 (cm) 3 / cm 2 / s and above. There is no specific limit to the upper limit, for example, from 500 (cm) 3 / cm 2 / s) Select appropriately from the following. It should be noted that the air permeability of the glass cloth is determined according to the method for determining the air permeability of cloth in JIS R 3420.

[0035] The dielectric loss tangent of the glass cloth at 10 GHz is preferably less than 0.0070°, more preferably less than 0.0020°, and even more preferably less than 0.0010°. The method for measuring the dielectric loss tangent is based on the resonance method, specifically, based on the description of the embodiments described later. Furthermore, a silane coupling agent may be adhered to the surface of the glass cloth, as described in the description of the manufacturing method.

[0036] [Method for manufacturing glass cloth]

[0037] There are no particular limitations on the manufacturing method of the glass cloth of the present invention. For example, a manufacturing method that includes an etching process for the glass cloth can be listed.

[0038] [Glass cloth before etching]

[0039] There are no particular limitations on the manufacturing method of the glass cloth before etching, but the following method is preferred: after manufacturing glass filaments, they are bundled into filament bundles, and then twisted yarns are manufactured, and the yarns are made into glass cloth using a weaving machine.

[0040] There are no particular limitations on the manufacturing method of glass filaments, but a preferred method is to heat and stretch a specified glass ingot; or to melt it into molten glass and then form it into filaments using a bushing. In particular, if the SiO2 content is 95% by mass or more, the melting temperature increases, making it difficult to stretch using a bushing, and a heating and stretching method using an oxyhydrogen burner is preferred.

[0041] Glass filament bundles are formed by coating the surface of glass filaments with an sizing agent and then binding them. Glass yarn is obtained by twisting the resulting glass filament bundles. The preferred twisting frequency is 0.1 to 5.0 times per 25 mm.

[0042] Glass cloth can be manufactured by weaving glass yarn. For the glass cloth of the present invention, the mass before etching during the manufacture of the thin cloth is preferably 5 to 50 g / m. 2 To reduce the amount of subsequent etching, a concentration of 5–25 g / m is preferred. 2 There are no particular limitations on the weaving method; for example, weaving methods using air-jet looms, water-jet looms, rapier looms, shuttle looms, etc., can be listed. When weaving using air-jet looms, etc., polyvinyl alcohol and starch can be applied as secondary sizing agents to further improve lubricity.

[0043] The diameter of the single fiber of the glass cloth before etching is preferably 3.0 μm or more, more preferably 3.5 μm or more. It can also be made to exceed 10 μm, making it 11 to 25 μm. If the single fiber diameter is too large or the glass cloth is too thick, the amount of etching required increases, which is not suitable in terms of productivity.

[0044] [Etching of glass cloth]

[0045] In particular, by etching the quartz glass cloth to which the sizing agent is attached after weaving, the diameter of the individual fibers can be adjusted while suppressing the generation of fuzz, and the sizing agent can also be removed. The etching solution used for adjusting the diameter of the individual fibers is not particularly limited, and can be selected from one or more acidic aqueous solutions such as hydrofluoric acid aqueous solution, acidic ammonium fluoride (NH4F·HF) aqueous solution, acidic potassium fluoride (KHF2) aqueous solution, ammonium fluoride aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, ammonia water, and alkaline electrolyzed water. Among these, alkaline electrolyzed water with a pH of 12.0 or higher (measured at 25°C) is preferred from the perspective of the working environment and wastewater treatment.

[0046] The etching conditions for the glass cloth are not particularly limited as long as the diameter of the individual fibers can be adjusted. The preferred temperature is room temperature (23°C) to 100°C, more preferably 40 to 80°C. If the temperature is below room temperature, the etching process may slow down; if the processing temperature exceeds 100°C, adjusting the etching amount may become difficult. The processing time is adjusted according to the processing temperature and the target diameter of the individual fibers. For example, under processing conditions at 60°C, the diameter of the quartz glass fibers can be reduced by approximately 0.035 μm per hour. Specifically, within the range of 40 to 80°C, 3 to 100 hours is preferred, more preferably 12 to 80 hours, and even more preferably 25 to 72 hours. After the target diameter of the individual fibers is achieved, the cloth can be washed with pure water or ion-exchanged water until the pH of the cleaning solution reaches 7, and then the water adhering to the glass cloth is dried by heating. There are no particular limitations on the cleaning method; methods such as immersion in cleaning water or spraying cleaning water can be included. In the case of immersion, stress such as ultrasonic waves can be applied. There are no particular limitations on the drying method; examples include hot air drying, infrared drying, and hot roller drying.

[0047] [Fiber Opening of Glass Cloth]

[0048] Fiberglass cloth can be split by etching. There are no particular limitations on the splitting process to achieve the desired degree of splitting; methods such as ultrasonic splitting, high-pressure columnar water jet splitting, and atmospheric diffusion jet spraying are examples. In particular, the method using a gas-liquid mixture mist with an adjusted gas-water volume ratio is preferred for its efficient fiber expansion while suppressing mesh misalignment and fuzzing of the filament bundles. Furthermore, etching also removes fuzz, thus enabling the production of fuzz-free cloth. There are no particular limitations on the timing of splitting; however, considering the slippage of the sizing agent, it is preferable to perform the splitting before its removal. Additionally, during etching, the sizing agent is removed, making it easier for the filaments to separate and split. With this splitting method, the air permeability of thin fiberglass cloth can be achieved at 300 cm⁻¹. 3 / cm 2 / s or less. Breathability is preferred at 30cm. 3 / cm 2 / s or higher, more preferably 50cm 3 / cm 2 / s or higher, further optimized for 50-280cm 3 / cm 2 / s. It should be noted that the air permeability was determined according to the method for determining the air permeability of fabrics in JIS R 3420.

[0049] [Silane Treatment of Glass Cloth]

[0050] Glass cloth after sizing agent removal can be used directly or made into silane-treated glass cloth. Especially glass cloth with sizing agent removed through long-term etching, where the etching reaction is Si-O-Si+OH-→SiOH+SiO - The reaction breaks the Si-O-Si bonds, thus easily generating SiOH groups locally on the etched surface. Therefore, by reacting the locally generated SiOH groups on the surface with the silane coupling agent, a low dielectric loss tangent can be achieved, while the strength is also increased.

[0051] As a silane coupling agent, there are no particular limitations, and examples include trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenylmethylvinylethoxysilane, naphthyltrimethoxysilane, naphthyltriethoxysilane, 1,4-bis(methoxydimethylsilyl)benzene, tetramethoxysilane, etc. 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-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyldimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane Alkoxysilane compounds such as 2-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane and its hydrochloride, N-(vinylbenzyl)-2-aminoethyl-3-aminopropylmethyldimethoxysilane and its hydrochloride, 3-isocyanatopropyltriethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and bis(triethoxysilylpropyl)tetrasulfide can be used, or one or a mixture of two or more can be used. Preferably, 3-aminopropyltrimethoxysilane, N-(2-(aminoethyl)-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane are also used.

[0052] There are no particular limitations on the silane treatment method; examples include impregnating glass fibers in an aqueous solution of a silane coupling agent dispersion and roller coating. Specifically, for thin glass cloths like those of this invention, a preferred method is to add a silane coupling agent to the etching solution after the target single fiber diameter has been achieved through the etching process. The added silane coupling agent is preferably in an amount of 0.01 to 1% by mass relative to the surface of the silane-treated glass cloth. For example, it is preferable to add it at a concentration of 0.01 to 1% by mass relative to the etching solution. By ensuring that the silane coupling agent adhering to the surface of the glass cloth is 0.01% or more by mass, it reacts sufficiently with the SiOH groups on the surface, resulting in a lower dielectric loss tangent. On the other hand, by ensuring that the silane coupling agent adhering to the surface of the glass cloth is 1% or less by mass, excessive adhesion of the silane coupling agent to the surface of the glass cloth is suppressed, thus maintaining the flexibility of the glass cloth while achieving a lower dielectric loss tangent. There is no particular limitation on the processing temperature, but 40–80°C is preferred to allow the silane coupling agent to hydrolyze rapidly and react with the surface of the quartz glass cloth. Regarding the processing time, there is no particular limitation as long as the processing time allows for, for example, 0.01–1% by mass of the silane coupling agent adhering to the surface of the silane-treated glass cloth, to adhere; 0.5–2 hours is preferred.

[0053] After silane treatment, the glass cloth can be washed with pure water or deion-exchanged water until the pH of the washing solution is preferably 7. Then, the water adhering to the glass cloth is dried by heating. At this time, excess silane coupling agent that has been physically adsorbed without reacting with the glass cloth is removed.

[0054] [Methods for adjusting the diameter of single fibers in glass cloth]

[0055] This invention provides a method for preparing the single fiber diameter of glass cloth, wherein the glass cloth is treated with an etching solution selected from one or more of hydrofluoric acid aqueous solution, ammonium fluoride aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, ammonia water, and alkaline electrolyzed water to etch away 0.1 μm or more of the single fiber diameter. The etching method is the same as the manufacturing method described above. The treatment temperature and treatment time are adjusted according to the target single fiber diameter. The etching diameter of the single fiber treated by etching 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 limitation on the upper limit, and it is appropriately selected from 10 μm or less.

[0056] The etching method is the same as 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 with a single fiber diameter of 3.0 μm or more using the etching solution to prepare 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.

[0057] [Composite Materials (Membranes)]

[0058] The glass cloth of the present invention has excellent dielectric loss tangent and small single fiber diameter, high air permeability and thin thickness, thus producing a film impregnated with organic resin.

[0059] The film of this invention, due to the use of glass cloth, achieves improved film strength and reduced thermal expansion coefficient, making it particularly suitable for adhesive films with excellent dielectric loss tangent. By stacking multiple layers of this adhesive film (prepreg), very thin substrates can be fabricated.

[0060] There are no particular limitations on the type of organic resin used. Examples include cyanate ester resins, bismaleimide-cyanate ester resins, epoxy resins, multifunctional maleimide resins, and polyphenylene ether resins containing unsaturated groups. One type can be used alone, or two or more can be used in combination. The amount of organic resin used is within a known range.

[0061] Example

[0062] The following examples and comparative examples illustrate the invention in detail, but the invention is not limited to the following examples.

[0063] [Example of preparation of sizing agent for quartz glass fiber]

[0064] 1. One-time application of adhesive:

[0065] A primary sizing agent for quartz glass fibers was prepared, consisting of 3.0% by mass starch, 0.5% by mass tallow, 0.1% by mass emulmin (manufactured by Sanyo Chemical Co., Ltd.) as an emulsifier, and the balance being water.

[0066] 2. Secondary sizing agent:

[0067] An aqueous solution consisting of 1.5% by mass of polyvinyl alcohol, 1.5% by mass of starch, and the balance being water was prepared.

[0068] [Example of glass cloth preparation]

[0069] 1. Fiberglass cloth A:

[0070] A glass ingot containing 53% by mass SiO2, 8% by mass B2O3, 15% by mass Al2O3, 21% by mass CaO, 2% by mass MgO, and 1% by mass each of Na2O and K2O was heated and stretched to produce glass fibers composed of glass filaments with a diameter of 4 μm. The glass fibers were then coated with a primary sizing agent using a coater and bundled and wound using a bundling machine to produce glass fiber bundles of 100 quartz glass filaments. The wound glass fiber bundles were then twisted at 24 T / m to produce glass yarn.

[0071] After applying a secondary sizing agent to the obtained glass yarn, glass cloth was manufactured using an air-jet loom at the fabric density of IPC standard 1027. The sizing agent-coated glass cloth was then subjected to fiber opening treatment using a PSN slit nozzle manufactured by H. Ikeuchi Co., Ltd., with tap water at 25°C and 0.3 MPa, and air compressed to 0.3 MPa, at an air-to-water volume ratio of V2 / V1 = 35. The resulting glass cloth is designated as Glass Cloth A.

[0072] 2. Fiberglass cloth B:

[0073] In addition to adjusting the glass composition of the raw materials to 55% by mass of SiO2, 15% by mass of B2O3, 15% by mass of Al2O3, 12% by mass of CaO, 2% by mass of MgO, and 1% by mass of Na2O and K2O, glass fibers composed of 4μm diameter glass filaments were produced using the same method as glass cloth A. The glass cloth was woven at the fabric density of IPC standard 1027 and then subjected to fiber opening treatment. The resulting glass cloth is designated as glass cloth B.

[0074] 3. Fiberglass cloth C:

[0075] Except for using a quartz glass ingot with 99.9% SiO2 by mass, glass fibers composed of glass filaments with a diameter of 4 μm were produced using the same method as glass cloth A. The glass cloth was woven at the fabric density of IPC standard 1027 and then subjected to fiber opening treatment. The resulting glass cloth is designated as glass cloth C.

[0076] 4. Fiberglass cloth D:

[0077] Filaments with a diameter of 3.6 μm were fabricated using a quartz glass ingot containing 99.9% SiO2 by mass. Thirty-eight filaments were bundled together and woven into quartz yarn using the same method as glass cloth A. The resulting glass cloth was manufactured to the fabric density specified in IPC standard 1006. This glass cloth is designated as glass cloth D.

[0078] 5. Glass cloth E: Comparative example

[0079] In addition to ensuring the glass composition of the raw materials was 40% by mass of SiO2, 8% by mass of B2O3, 22% by mass of Al2O3, 27% by mass of CaO, 2% by mass of MgO, and 1% by mass each of Na2O and K2O, glass fibers composed of 4μm diameter glass filaments were produced using the same method as glass cloth A. The glass cloth was woven at the fabric density of IPC standard 1027 and then subjected to fiber opening treatment. The resulting glass cloth is designated as glass cloth E.

[0080] 6. Glass cloth F: Comparative example

[0081] Filaments with a diameter of 2.5 μm were produced using a quartz glass ingot containing 99.9% SiO2 by mass. One hundred filaments were bundled together and quartz yarn was produced using the same method as for glass cloth D, but this resulted in more filament breakage and a lower yarn yield. Glass cloth was then woven using this yarn at the fabric density specified in IPC standard 1006. During the fiber opening process, the resulting glass cloth experienced fiber breakage, forming uneven basket holes, and ultimately failed to yield a usable glass cloth.

[0082] The physical properties of the prepared glass cloth are shown in Table 1.

[0083] Table 1

[0084] Types of glass cloth A B C D E F Filler particle size (μm) 4 4 4 3.6 4 2.5 <![CDATA[SiO2 content (mass%)]]> 53 55 99.9 99.9 40 99.9 <![CDATA[Content of SiO2 + B2O3 (mass%)]]> 61 70 99.9 99.9 48 99.9 Fabric thickness (μm) 20.0 20.0 20.0 11.0 20.0 7.8 <![CDATA[Mass (g / m 2 )]]> 20.0 17.7 16.5 7.5 20.5 7.8 IPC Standard for Glass Cloth 1027 1027 1027 1006 1027 1027 Weaving* ○ ○ ○ ○ ○ ×

[0085] *○: Can be made into yarn and glass cloth

[0086] ×: Broken yarn or fabric fibers occurred.

[0087] [Example 1]

[0088] Glass cloth A was placed in an alkali-resistant etching tank, and alkaline electrolyzed water S-2665 (pH 12 (measured at 25°C) manufactured by Suzuki Oil & Fat Industry Co., Ltd.) was poured into it until the glass cloth was impregnated. The tank was then sealed and etched at 60°C for 72 hours. Then, 0.2% by weight of 3-methacryloylpropyltrimethoxysilane (KBM-503: manufactured by Shin-Etsu Chemical Industry) was added relative to the alkaline electrolyzed water, and the tank was treated at 60°C for 1 hour. The alkaline electrolyzed water was then drained from the etching tank and replaced with (3 times) ion-exchange water until the pH reached 7, and the quartz glass cloth was cleaned. The cleaned etching cloth was air-dried at 110°C for 10 minutes using a blower-driven humidity and temperature control system DKN602 manufactured by Yamato Scientific Co., Ltd.

[0089] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth A are shown in Table 2.

[0090] [Example 2]

[0091] Glass cloth B was placed in an alkali-resistant etching bath and, in the same manner as in Example 1, was coupled during the etching process, followed by cleaning and drying.

[0092] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth B are shown in Table 2.

[0093] [Example 3]

[0094] Glass cloth C was placed in an alkali-resistant etching bath and, in the same manner as in Example 1, was coupled during the etching process, followed by cleaning and drying.

[0095] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth C are shown in Table 2.

[0096] [Example 4]

[0097] Except that the glass cloth C was placed in an alkali-resistant etching bath and the etching time was changed to 31 hours, the treatment was the same as in Example 3.

[0098] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth C are shown in Table 2.

[0099] [Example 5]

[0100] Except that the glass cloth C was placed in an alkali-resistant etching bath and the etching time was changed to 100 hours, the treatment was the same as in Example 3.

[0101] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth C are shown in Table 2.

[0102] [Example 6]

[0103] Except for placing the glass cloth C into an alkali-resistant etching bath, changing the etching temperature to 80°C, and changing the etching time to 100 hours, the treatment was the same as in Example 3.

[0104] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth C are shown in Table 3.

[0105] [Example 7]

[0106] Except for placing the glass cloth D into an alkali-resistant etching bath, changing the etching temperature to 60°C, and changing the etching time to 60 hours, the treatment was the same as in Example 1.

[0107] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth D are shown in Table 3.

[0108] [Comparative Example 1]

[0109] Except for placing the glass cloth C into the alkali-resistant etching bath, changing the etching temperature to 60°C, and changing the etching time to 10 hours, the treatment was the same as in Example 3.

[0110] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth C are shown in Table 3.

[0111] [Comparative Example 2]

[0112] Except for placing the glass cloth C into the alkali-resistant etching bath, changing the etching temperature to 10°C, and changing the etching time to 110 hours, the treatment was the same as in Example 3.

[0113] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth C are shown in Table 3.

[0114] [Comparative Example 3]

[0115] Except for placing the glass cloth E into the alkali-resistant etching bath, changing the etching temperature to 60°C, and changing the etching time to 31 hours, the treatment was the same as in Example 1.

[0116] The single fiber diameter, thickness, weight, and air permeability of the etched glass cloth E are shown in Table 3.

[0117] The glass cloth obtained above was evaluated using the following method. The results are recorded in Tables 2 and 3 below.

[0118] 1. Determination of single fiber diameter

[0119] Using room-temperature curing epoxy resin NER-814 manufactured by Nisshin EM Co., Ltd., the glass cloth was vertically fixed and the surface was ground. The diameter of the quartz glass filament was measured at 10 points using a scanning electron microscope JSM-IT700HR InTouchScope manufactured by Nippon Electron Co., Ltd., and the average value was set as the single fiber diameter.

[0120] 2. Thickness Measurement

[0121] The thickness of fabrics and felts was determined according to the method for determining the thickness of fabrics and felts as per JIS R3420.

[0122] 3. Determination of mass per unit area

[0123] The quality of fabrics and felts was determined according to the JIS R3420 method for determining quality.

[0124] 4. Measurement of air permeability

[0125] The air permeability of fabric was determined according to the JIS R3420 method for determining air permeability.

[0126] 5. Adhesion amount of silane coupling agent (high thermal loss)

[0127] The moisture content and thermal loss were determined according to the method for determination of moisture content and thermal loss in JIS R3420.

[0128] 6. Determination of dielectric loss tangent

[0129] The dielectric loss tangent of the glass cloth at 10 GHz was measured using a void resonator (TE011 mode) manufactured by AET Corporation. Furthermore, the thickness of the glass cloth was determined using the theoretical film thickness, which is calculated by the following formula.

[0130] Theoretical film thickness t (μm) = mass (g / m) 2 ) / Specific gravity (g / cm 3 )

[0131] Table 2

[0132]

[0133] Table 3

[0134]

[0135] Tables 2 and 3 show that the method of this invention can produce glass cloth with a single fiber diameter of less than 3.0 μm, a thickness of less than 15 μm, and a mass of 10 g / m³. 2 The following is about quartz glass cloth. Currently, even though filaments with a single fiber diameter of less than 3.0 μm can be tested and produced, mass production is difficult.

[0136] According to the present invention, by employing an etching process to subsequently adjust the single fiber diameter of conventional glass cloth, a thin quartz glass cloth with a single fiber diameter of less than 3.0 μm, which could not be woven until now, is obtained. Therefore, it has the significant effect of enabling integration into substrates used in future high-speed communications such as 5G and suppressing transmission losses. In particular, it is expected to serve as a thin-film glass cloth for reinforcing adhesive films with low-roughness copper plating.

[0137] Furthermore, this invention is not limited to the embodiments described above. The embodiments described above are illustrative examples, and any technical solutions having a substantially similar structure and achieving the same effect as those described in the patent claims of this invention are included within the technical scope of this invention.

Claims

1. Glass cloth, comprising a composition of more than 50% by mass SiO2, wherein the diameter of any single fiber of either the warp or weft of the glass cloth is less than 3.0 μm, the thickness of the glass cloth is less than 15 μm, and the mass is 10 g / m³. 2 the following.

2. The glass cloth according to claim 1, wherein, The total content of SiO2 and B2O3 contained in the composition is more than 65% by mass.

3. The glass cloth according to claim 1, wherein, The composition contains more than 95% SiO2 by mass, and the thickness of the glass cloth is less than 10 μm.

4. The glass cloth according to claim 1, wherein, Breathability is 50 (cm) 3 / cm 2 / s) and above.

5. A method for manufacturing glass cloth according to any one of claims 1 to 3, comprising an etching step of treating the glass cloth with an etching solution selected from one or more of aqueous hydrofluoric acid solution, aqueous ammonium fluoride solution, aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, aqueous sodium carbonate solution, ammonia solution, and alkaline electrolyzed water.

6. Methods for adjusting the diameter of single fibers in glass cloth, among which, The glass cloth is treated with an etching solution selected from one or more of the following: hydrofluoric acid aqueous solution, ammonium fluoride aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, ammonia water, and alkaline electrolyzed water, to etch away more than 0.1 μm of the diameter of a single fiber of the glass cloth.

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

8. The method for adjusting the diameter of a single fiber according to claim 6 or 7, wherein, Glass cloth with 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 glass cloth according to any one of claims 1 to 4, and an organic resin.

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