Method for storing glass cloth and glass cloth package

Abstract

The present disclosure provides a glass cloth storage method and a glass cloth package with which it is possible to maintain the dielectric properties of a glass cloth having excellent dielectric characteristics. In the glass cloth, a glass yarn including a plurality of filaments is configured as a warp and a weft, and the dielectric loss tangent at 10 GHz of the glass cloth is 0.00200 or less. The storage method includes storing the glass cloth in an atmosphere in which the storage environment has an average dew point of 18°Cdp or less and an average temperature of 100°C or less under atmospheric pressure. The package includes a packaging material and a glass cloth housed inside the packaging material, and the water vapor permeability measured under conditions of 40°C and 90% Rh of the packaging material is 8 g / (m2×24 hr) or less.

Description

Technical Field

[0001] The present disclosure relates to a method for storing a glass cloth and a glass cloth package. This international application claims priority based on Japanese Patent Application No. 2023-124261 filed on July 31, 2023, and Japanese Patent Application No. 2023-129381 filed on August 8, 2023, and incorporates the entire contents of the Japanese patent applications herein.

Background Art

[0002] Currently, the performance of information terminals such as smartphones is improving, and high-speed communication represented by 5G communication is progressing. Against this background, for example, for printed wiring boards for high-speed communication, not only improvement in heat resistance but also further improvement in dielectric properties of the insulating material (for example, lowering of the dielectric tangent) is desired. Similarly, improvement in dielectric properties is desired for prepregs used as insulating materials for printed wiring boards, glass yarns included in the prepregs, and glass cloths.

[0003] As a means for improving dielectric properties, for example, a method of producing a prepreg using a low-dielectric glass is known (see Patent Documents 1 and 2). More specifically, Patent Document 1 describes producing a prepreg using glass yarn having a silicon dioxide (SiO2) composition amount of 98% by mass or more and 100% by mass or less. Patent Document 2 describes heat-treating quartz glass cloth for the purpose of further lowering the dielectric tangent.

[0004] Patent Document 3 states that the Si-OH groups on the surface of quartz glass are highly active. Especially in a high-temperature atmosphere, they incorporate moisture through hydrogen bonding and further generate Si-OH groups by cleaving the Si-O-Si bond (SiO2 + H2O ⇔ Si-OH), and the generated Si-OH groups deteriorate the dielectric tangent of the glass cloth (paragraph 0006). Therefore, for the purpose of re-bonding the Si-OH groups to form Si-O-Si bonds and reducing the dielectric tangent of the glass cloth, when heat-treating the quartz glass cloth, it is described that heating is performed in a vacuum or a gas with a dew point of 15°C or lower under the conditions that the maximum heating temperature is 100°C to 600°C and the heating amount represented by the heating temperature (°C) × heating time (h) at 100°C or higher is 450 (°C·h) or more (Claim 1, etc.).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] Patent Document 3 describes that the reaction of SiO2 + H2O ⇔ Si-OH has insufficient activation energy at temperatures below 100°C (paragraph 0025). Thus, conventionally, it has been considered that water has no effect on the dielectric tangent of the glass cloth in the temperature range below 100°C. In this regard, the present inventors have found for the first time that even if the dielectric tangent during the production of the glass cloth is reduced by the means disclosed in Patent Documents 1 to 3, when the glass cloth is stored for a long period of time, the generation of silanol groups by the above equilibrium reaction proceeds even in an environment below 100°C, and the dielectric tangent of the glass cloth increases.

[0007] Therefore, one object of the present disclosure is to provide a method for storing a glass cloth and a glass cloth package that can maintain the dielectric properties of a glass cloth having excellent dielectric properties.

Means for Solving the Problems

[0008] Some embodiments of the present disclosure are exemplified in the following items [1] to

[57] . [1] A method for storing a glass cloth, wherein the glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft, and the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less, and the method includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 18 °C dp or less and the average temperature is 100 °C or less. [2] The method according to item 1, wherein the silicon (Si) content in the glass yarn is 95.0 mass% to 100 mass% in terms of silicon dioxide (SiO2). [3] The method according to item 1 or 2, wherein the glass cloth has a surface treatment agent containing a silane coupling agent on its surface. [4] The surface treatment agent is represented by the following formula (1): X(R) 3-n SiY n ···(1) (In formula (1), X is an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is each independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group) The method according to item 3, which includes a silane coupling agent represented by the formula. [5] The method according to item 4, wherein the surface treatment agent contains two or more kinds of silane coupling agents having different Xs in the formula (1). [6] The method according to any one of Items 3 to 5, wherein the surface treatment agent contains two or more silane coupling agents having different molecular weights. [7] The method according to any one of Items 3 to 6, further comprising a step of surface-treating the glass cloth with a surface treatment agent containing a silane coupling agent before the storage, and a step of fibrillating the surface-treated glass cloth. [8] The method according to any one of Items 1 to 7, wherein the dielectric tangent of the glass cloth at 10 GHz is 0.00051 or more and 0.00200 or less. [9] The method according to any one of Items 1 to 8, wherein the driving-in density of the warp and / or weft of the glass cloth is in the range of 66 to 120 threads / inch (= 66 to 120 threads / 25 mm).

[10] The method according to any one of Items 1 to 9, further comprising a step of heating the glass cloth at a temperature of 600°C or higher while conveying it in a Roll-to-Roll manner before the storage.

[11] The method according to any one of Items 1 to 10, wherein the glass cloth is stored as a package wrapped with a box and / or a film-like packaging material.

[12] The method according to Item 11, wherein the glass cloth is stored as a package wrapped with a film-like packaging material, and the thickness of the film-like packaging material is 50 μm or more.

[13] The method according to Item 11 or 12, wherein the glass cloth is stored as a package wrapped with a film-like packaging material, and the film-like packaging material is an aluminum laminate film.

[14] The method according to any one of Items 11 to 13, wherein the glass cloth is stored as a package wrapped with a film-like packaging material in a state of a roll wound around a hollow columnar core tube, and the film-like packaging material has a recess extending into the hollow portion from one end or both ends of the core tube, or is an annular shape penetrating the hollow portion of the core tube.

[15] The method according to item 14, wherein the ratio of the volume occupied by the space inside the film-like packaging material to the hollow volume of the core tube is 50% or less of the hollow volume of the core tube.

[16] The method according to item 14 or 15, wherein the film-like packaging material is in an annular shape penetrating the hollow portion of the core tube.

[17] The method according to item 14 or 15, wherein the package is configured such that the glass cloth is sealed from the external environment by the film-like packaging material and the core tube.

[18] The water vapor permeability of the core tube measured under the conditions of 40 ° C and 90% Rh is 8 g / (m 2 ×24 hr) or less, and the method according to any one of items 14 to 17.

[19] The packaging material has a water vapor permeability of 8 g / (m 2 ×24 hr) or less at a measurement temperature of 40 ° C and a measurement humidity of 90% Rh, and the method according to any one of items 11 to 18.

[20] The package is configured to dehumidify so as to maintain the average dew point inside the package at 18 ° C dp or less, and the method according to any one of items 11 to 19.

[21] The method according to any one of items 1 to 20, including storing at an average dew point of 13 ° C dp or more and 18 ° C dp or less under the atmospheric pressure of the storage environment.

[22] The method according to any one of items 1 to 20, including storing at an average dew point of -21 ° C dp or less under the atmospheric pressure of the storage environment.

[23] The method according to any one of items 11 to 19, wherein a moisture absorbent is provided in the package.

[24] The enclosed amount of the moisture absorbent is represented by the following formula (2): WVTR [g / (m 2 ×24 hr)] × package surface area [m 2 / enclosed amount of moisture absorbent [g] ≦ 0.0030 ···(2) The method according to item 23, which satisfies (in formula (2), WVTR is the water vapor permeability of the packaging material at a measurement temperature of 40°C and a measurement humidity of 90%Rh).

[25] The method according to item 23 or 24, wherein the desiccant is at least one selected from the group consisting of silica gel, calcium oxide, calcium chloride, calcined diatomaceous earth, synthetic zeolite, clay-based desiccant, phosphorus pentoxide, magnesium sulfate, copper sulfate, magnesium chloride, cobalt chloride, granular soda lime, and magnesium perchlorate.

[26] The method according to any one of items 23 to 25, wherein the desiccant is a sheet-shaped desiccant.

[27] The method according to any one of items 1 to 26, wherein the atmosphere is dry air with an average dew point of 18°C dp or lower, or a gas containing at least one selected from the group consisting of nitrogen, argon, and oxygen and having an average dew point of 18°C dp or lower.

[28] The method according to any one of items 1 to 27, wherein the atmosphere is depressurized to less than atmospheric pressure.

[29] The method according to any one of items 1 to 28, wherein the glass cloth is stored in a storage room with controlled dew point and temperature.

[30] The basis weight (mass of the glass cloth) of the glass cloth is in the range of 8 to 25 g / m 2 The method according to any one of items 1 to 29.

[31] A glass cloth package including a packaging material and a glass cloth stored inside the packaging material, wherein the glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft, the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less, the packaging material is sealed, the water vapor permeability of the packaging material measured under the conditions of 40°C and 90%Rh is 8 g / (m 2 ×24 hr) or less. The glass cloth package.

[32] The glass cloth package according to item 31, wherein the packaging material is a box and / or a film.

[33] The glass cloth package according to item 32, wherein the packaging material is a film and the thickness of the film is 50 μm or more.

[34] The glass cloth package according to item 32 or 33, wherein the packaging material is a film and the film is an aluminum laminate film.

[35] The glass cloth package according to any one of items 32 to 34, wherein the glass cloth is packaged in a film in a state of a roll wound around a hollow columnar core tube, and the film has a recess extending into the hollow portion from one end or both ends of the core tube, or is an annular shape penetrating the hollow portion of the core tube.

[36] The glass cloth package according to item 35, wherein the ratio of the space inside the film to the volume of the hollow portion of the core tube is 50% or less of the volume of the hollow portion of the core tube.

[37] The glass cloth package according to item 35 or 36, wherein the film is an annular shape penetrating the hollow portion of the core tube.

[38] The glass cloth package according to item 35 or 36, wherein the package is configured such that the glass cloth is sealed from the external environment by the film and the core tube.

[39] The water vapor permeability of the core tube measured under the conditions of 40 °C and 90% Rh is 8 g / (m 2 ×24 hr) or less. The glass cloth package according to any one of items 35 to 38.

[40] The glass cloth package according to any one of items 31 to 39, wherein the dew point inside the packaging material is 18 °C dp or less.

[41] The glass cloth package according to any one of items 31 to 39, wherein the dew point inside the packaging material is 13 °C dp or more and 18 °C dp or less.

[42] The glass cloth package according to any one of items 31 to 39, wherein the dew point inside the packaging material is -21°C dp or lower.

[43] The glass cloth package according to any one of items 31 to 42, wherein the glass cloth is in a roll state.

[44] The glass cloth package according to any one of items 31 to 43, wherein a moisture absorbent is enclosed inside the packaging material.

[45] The enclosed amount of the moisture absorbent satisfies the following formula (2): WVTR [g / (m 2 ×24hr)] × packaging body surface area [m 2 / moisture absorbent enclosed amount [g] ≤ 0.0030 ···(2) (In formula (2), WVTR is the water vapor permeability of the packaging material at a measurement temperature of 40°C and a measurement humidity of 90% Rh.) The glass cloth package according to item 44.

[46] The glass cloth package according to item 44 or 45, wherein the moisture absorbent is at least one selected from the group consisting of silica gel, calcium oxide, calcium chloride, calcined diatomaceous earth, synthetic zeolite, clay-based desiccant, phosphorus pentoxide, magnesium sulfate, copper sulfate, magnesium chloride, cobalt chloride, granular soda lime, and magnesium perchlorate.

[47] The glass cloth package according to any one of items 44 to 46, wherein the moisture absorbent is in a sheet shape.

[48] The glass cloth package according to any one of items 31 to 47, wherein the inside of the packaging material is filled with dry air having a dew point of 18°C dp or lower, or a gas containing at least one selected from the group consisting of nitrogen, argon, and oxygen and having a dew point of 18°C dp or lower.

[49] The glass cloth package according to any one of items 31 to 48, wherein the inside of the packaging material has a pressure lower than atmospheric pressure.

[50] The glass cloth packaging body according to any one of items 31 to 49, wherein the silicon (Si) content in the glass fiber is 95.0% to 100% by mass in terms of silicon dioxide (SiO2).

[51] The glass cloth packaging body according to any one of items 31 to 50, wherein the glass cloth is treated with a surface treatment agent containing a silane coupling agent.

[52] The surface treatment agent is represented by the following formula (1): X(R) 3-n SiY n ···(1) (In formula (1), X is an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is each independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group) The glass cloth packaging body according to item 51, containing the silane coupling agent represented by the above formula (1).

[53] The glass cloth packaging body according to item 52, wherein the surface treatment agent contains two or more kinds of silane coupling agents having different Xs in the above formula (1).

[54] The glass cloth packaging body according to any one of items 51 to 53, wherein the surface treatment agent contains two or more kinds of silane coupling agents having different molecular weights.

[55] The glass cloth packaging body according to any one of items 31 to 54, wherein the dielectric loss tangent of the glass cloth at 10 GHz is 0.00051 or more and 0.00200 or less.

[56] The glass cloth packaging body according to any one of items 31 to 55, wherein the driving density of the warp and / or weft of the glass cloth is in the range of 66 to 120 threads / inch (= 66 to 120 threads / 25 mm).

[57] The glass cloth packaging body according to any one of items 31 to 56, wherein the basis weight (mass of the glass cloth) is in the range of 8 to 25 g / m 2 .

Advantages of the Invention

[0009] According to the present disclosure, it is possible to provide a method for storing a glass cloth and a glass cloth package that can maintain the dielectric properties of a glass cloth having excellent dielectric properties.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present disclosure (hereinafter referred to as "the present embodiment") will be described. The present disclosure is not limited to the present embodiment, and various modifications are possible without departing from the gist thereof. In the present embodiment, a numerical range described using "~" includes the numerical values before and after "~" as the lower limit value and the upper limit value. In the present embodiment, in a numerical range described step by step, the upper limit value or the lower limit value described in a certain numerical range can be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. In the present embodiment, the upper limit value or the lower limit value described in a certain numerical range can also be replaced with the value shown in the examples. In the present embodiment, the term "step" includes not only an independent step but also this term even when it cannot be clearly distinguished from other steps as long as the function of the step is achieved.

[0012] 《Method for Storing Glass Cloth》 The storage method of the glass cloth of the present disclosure relates to a method of storing a glass cloth composed of glass yarns including a plurality of filaments as warp and weft, wherein the dielectric loss tangent at 10 GHz is 0.00200 or less. And the method of the present disclosure includes storing the above glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 18 °C dp or less and the average temperature is 100 °C or less. Conventionally, in the temperature range below 100 °C, it has been considered that the reaction in which the Si-O-Si bond is cleaved by moisture to generate Si-OH groups is not activated, so the storage method of the glass cloth has not been particularly considered, and the dielectric loss tangent may increase with time. In this regard, by using the method of the present disclosure, the cleavage of the Si-O-Si bond by the moisture in the storage environment to generate Si-OH groups is suppressed, so that the increase in the dielectric loss tangent of the glass cloth with time can be suppressed. In the present disclosure, "suppression" does not mean that the dielectric loss tangent does not increase at all, and it is sufficient that the increase in the dielectric loss tangent is suppressed to a certain extent.

[0013] 〈Glass Cloth〉 The glass cloth has a structure woven with glass yarns including a plurality of glass filaments as warp and weft. The weave structure of the glass cloth includes weave structures such as plain weave, nanako weave, satin weave, twill weave, etc. Among them, a plain weave structure is preferred.

[0014] The driving-in density of the warp and weft constituting the glass cloth is, independently of each other, preferably 10 to 120 threads / inch (= 10 to 120 threads / 25 mm). The lower limit value of the driving-in density is more preferably 20 threads / inch or more, 30 threads / inch or more, 40 threads / inch or more, 50 threads / inch or more, 60 threads / inch or more, or 66 threads / inch or more. The upper limit value of the driving-in density is more preferably 110 threads / inch or less, or 100 threads / inch or less. If the driving-in density is within the above range, it is easy to obtain a glass cloth with a preferable thickness. The driving-in densities of the warp and weft may be different.

[0015] The basis weight (mass of the glass cloth) of the glass cloth is preferably 8 to 250 g / m2 , more preferably 8 to 100 g / m 2 , even more preferably 8 to 80 g / m 2 , still more preferably 8 to 50 g / m 2 , particularly preferably 8 to 25 g / m 2 , or 8 to 23.2 g / m 2 . If the basis weight of the glass cloth is within the above range, it is easy to obtain a glass cloth with a preferable thickness.

[0016] The thickness of the glass cloth is preferably more than 0 and 60 μm or less. The upper limit value of the thickness of the glass cloth is more preferably 55 μm or less, and even more preferably 50 μm or less. If the thickness of the glass cloth is within the above range, it is easy to obtain a glass cloth suitable as an insulating material. The lower limit value of the thickness of the glass cloth is more preferably 5 μm or more, or 10 μm or more.

[0017] 〈Dielectric tangent of glass cloth〉 The glass cloth has a dielectric tangent at 10 GHz, measured by the method described in the examples, of 0.00200 or less. In such a glass cloth, even at a temperature of 100°C or lower, the dielectric tangent of the glass cloth increases over time due to the influence of water in the storage environment. Therefore, by setting the average dew point temperature of the storage environment of the glass cloth to 18°C dp or lower, an increase in the dielectric tangent of the glass cloth can be suppressed. Here, the "storage environment" means the atmosphere (gas) with which the glass cloth is in direct contact.

[0018] The dielectric tangent of the glass cloth at 10 GHz is preferably 0.00010 or more and 0.00200 or less. The upper limit value of the dielectric tangent is 0.00200 or less, preferably 0.00160 or less, more preferably 0.00120 or less, still more preferably 0.00090 or less, even more preferably 0.00070 or less, particularly preferably 0.00050 or less, and particularly preferably 0.00040 or less. The lower limit value of the dielectric tangent is preferably 0.00010 or more, 0.00015 or more, 0.00020 or more, 0.00028 or more, and 0.00030 or more. When the dielectric tangent of the glass cloth is within the above range, the glass cloth is more likely to be affected by the moisture around it in the storage environment, so the effect of suppressing the increase in the dielectric tangent is easily obtained.

[0019] 〈Glass fiber〉 The glass fiber constituting the glass cloth is preferably obtained using low-dielectric glass as a raw material. The low-dielectric glass fiber more preferably has a silicon (Si) content of 95.0 mass% or more and 100 mass% or less in terms of SiO2. By using such glass fiber, the dielectric properties of the obtained glass cloth can be improved. Also, in such glass fiber, since the increase in the dielectric tangent of the glass cloth over time is remarkable, the effect of suppressing the increase in the dielectric tangent is easily obtained. From the viewpoint of improving the dielectric properties, the Si content is preferably 99.0 mass% or more, more preferably 99.5 mass% or more, and still more preferably 99.9 mass% or more.

[0020] The average filament diameter of the glass filaments constituting the glass fiber is preferably 2.5 μm or more and 9.0 μm or less, more preferably 2.5 μm or more and 7.5 μm or less, still more preferably 3.5 μm or more and 7.0 μm or less, even more preferably 3.5 μm or more and 6.0 μm or less, and particularly preferably 3.5 μm or more and 5.0 μm or less. When the filament diameter is at least the above lower limit value, it is easy to ensure the breaking strength of the filament, so it is difficult for fluff to occur in the obtained glass cloth. Also, when the filament diameter is less than the above upper limit value, it is possible to prevent the mass of the glass cloth from becoming too large, so it is easy to carry out conveyance or processing.

[0021] 〈Silane coupling agent〉 The glass cloth preferably has a surface treatment agent containing a silane coupling agent on its surface. More specifically, the glass filaments (including glass filaments) constituting the glass cloth are preferably surface-treated with a surface treatment agent containing a silane coupling agent. When the glass cloth has a surface treatment agent, the reactivity with the matrix resin tends to improve. In addition, since it is less likely to be affected by moisture during storage, it is possible to more effectively suppress the increase in the dielectric tangent over time.

[0022] Examples of the silane coupling agent include the following formula (1): X(R) 3-n SiY n ···(1) {In formula (1), X is an organic functional group having at least one of an unsaturated double bond group having radical reactivity such as a carbon-carbon double bond having radical reactivity and an amino group, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group} It is preferable to use a silane coupling agent represented by the above formula.

[0023] From the viewpoint of reactivity with the matrix resin, X in formula (1) is more preferably an organic functional group having one or more methacryloxy groups or acryloxy groups.

[0024] Regarding Y in the above formula (1), as the alkoxy group, an alkoxy group having 1 to 5 carbon atoms (the carbon number is 1, 2, 3, 4, or 5) is preferable for the stable treatment of the glass cloth.

[0025] As a surface treatment agent, the silane coupling agent represented by the formula (1) may be used alone or may be used in admixture with two or more silane coupling agents having different Xs in the formula (1). Further, as the silane coupling agent represented by the formula (1), for example, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 5-hexenyltrimethoxysilane, etc. may be used alone or as a mixture thereof.

[0026] The molecular weight of the silane coupling agent is preferably 100 to 600, more preferably 150 to 500, still more preferably 200 to 450. Among them, it is particularly preferable to use two or more silane coupling agents having different molecular weights. By treating the glass fiber surface with two or more silane coupling agents having different molecular weights, the density of the treatment agent on the glass surface increases, and the reactivity with the matrix resin tends to be further improved.

[0027] From the viewpoint of being difficult to inhibit the reactivity with the resin, the silane coupling agent is preferably nonionic. Among the nonionic silane coupling agents, a silane coupling agent having at least one group selected from the group consisting of a vinyl group, a methacryloxy group, and an acryloxy group is preferable, and among them, a silane coupling agent having at least one methacryloxy group or acryloxy group is particularly preferable. By not inhibiting the reactivity with the resin, the heat resistance and reliability of the printed wiring board can be enhanced.

[0028] 〈Loss on Ignition Value〉 The loss on ignition value of the glass cloth is preferably 0.01% by mass or more and less than 2.0% by mass, more preferably 0.01% by mass or more and less than 1.5% by mass, still more preferably 0.02% by mass or more and less than 1.0% by mass, even more preferably 0.03% by mass or more and less than 0.8% by mass, and particularly preferably 0.03% by mass or more and less than 0.3% by mass. When the loss on ignition value is within the above range, it is easy to obtain a glass cloth showing a low dielectric tangent. Here, the loss on ignition value is measured in accordance with JIS R3420.

[0029] 〈Storage of Glass Cloth〉 The storage method of the glass cloth includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 18°C dp or less and the average temperature is 100°C or less. Here, the "storage environment" means the atmosphere directly contacting the glass cloth. By controlling the storage environment of the glass cloth within the above range, an increase in the dielectric tangent of the glass cloth over time due to water present in the storage environment can be suppressed.

[0030] The storage period of the glass cloth, that is, the period during which the storage environment in the present disclosure is maintained, is not particularly limited. However, from the viewpoints of the time required for transporting the glass cloth and improving supply stability, etc., it is preferably 30 days or more and 5 years or less. The lower limit value of the storage period is preferably 30 days or more, more preferably 90 days or more, still more preferably 180 days or more, even more preferably 365 days or more, and particularly preferably 730 days or more. Also, from the viewpoint of reducing storage costs, etc., the upper limit value of the storage period of the glass cloth is preferably 5 years or less, more preferably 3 years or less. If the storage period is within the above range, the effect of maintaining the storage environment can be sufficiently obtained. The longer the storage period, the more remarkable the effect of suppressing the increase in the dielectric tangent can be obtained.

[0031] 〈Average Dew Point in the Storage Environment of Glass Cloth〉 The storage method of the glass cloth is such that the average dew point under the atmospheric pressure of the storage environment of the glass cloth is 18°C dp or less. Also, the average dew point is the average dew point during the storage period. Preferably, it is controlled so that the dew point of the storage environment is maintained at 18°C dp or less throughout the storage period. When the average dew point is 18°C dp or less, it is possible to prevent the increase in the dielectric tangent of the glass cloth over time. The average dew point is preferably -50°C dp or more and 18°C dp or less. The lower limit value of the average dew point may more preferably be -40°C dp or more, -32°C dp or more, -30°C dp or more, -20°C dp or more, -10°C dp or more, 0°C dp or more, 10°C dp or more, or 13°C dp or more. The upper limit value of the average dew point that can be arbitrarily combined with the above lower limit value may more preferably be 15°C dp or less, 10°C dp or less, 5°C dp or less, 0°C dp or less, -5°C dp or less, -10°C dp or less, -15°C dp or less, -20°C dp or less, or -21°C dp or less.

[0032] In the storage method of the glass cloth, if the average dew point is 18°C dp or less, the dew point may exceed 18°C dp in part of the storage period. Preferably, it is controlled so that the dew point of the storage environment is maintained at 18°C dp or less throughout the storage period. As a method for controlling the average dew point within the above range, known humidity control methods, humidity control media, humidity control mechanisms, and humidity control devices can be used. For example, (1) using a moisture absorbent, (2) replacing the ambient atmosphere with a gas having a predetermined moisture content (for example, a dry gas), (3) performing dehumidification of the ambient atmosphere by utilizing condensation at a low temperature, (4) performing depressurization to make the ambient atmosphere have a predetermined moisture content, and (5) combinations thereof.

[0033] The dew point can be controlled continuously or intermittently (regularly or irregularly) in an open system or a closed system as long as the average dew point is controlled within the above range. For example, the above controls (1) to (5) can be carried out continuously in a closed system (for example, inside a sealed packaging material (packaging)), intermittently in a closed system (for example, only on days in seasons or weather when the dew point is likely to rise), continuously controlling the change in the dew point around the glass cloth in an open system, and the like. When maintaining the dew point by continuous humidity control, it is preferable to use a desiccant, replacement of dry gas, a dehumidifier, etc.

[0034] 〈Desiccant〉 When using a desiccant to control the dew point, the type of desiccant is not limited as long as the average dew point can be controlled within the above range. From the perspective of moisture absorption capacity, the desiccant is preferably at least one selected from the group consisting of silica gel, calcium oxide, calcium chloride, calcined diatomaceous earth, synthetic zeolite, clay-based desiccant, phosphorus pentoxide, magnesium sulfate, copper sulfate, magnesium chloride, cobalt chloride, granular soda lime, and magnesium perchlorate. Among them, it is preferably at least one selected from the group consisting of silica gel, calcium oxide, calcium chloride, and calcined diatomaceous earth. Also, from the perspective of occupied space and packaging (packing) form, it is preferable to use a sheet-shaped desiccant.

[0035] The amount of desiccant used is not limited as long as the average dew point can be controlled within the above range, but it is preferable to use an appropriate amount according to the moisture absorption capacity (moisture absorption amount and moisture absorption time) of the desiccant, the storage period, etc. Regarding the moisture absorption amount, it is preferable to use an amount sufficient or more. That is, it is preferable that the maximum moisture absorption amount that the desiccant can absorb is larger than the moisture amount in the atmosphere. Or, by periodically replacing the desiccant, it becomes easy to keep the storage environmental conditions of the glass cloth constant.

[0036] When the storage period is long, the amount of desiccant used becomes more important. If the amount of desiccant is appropriate, it is easy to maintain the dew point of the storage environment during the long-term storage period and suppress the increase in the dielectric loss tangent. The dew point of the storage environment, that is, the amount of water vapor present inside the package, is affected by the water vapor transmission rate of the packaging material, the surface area of the package, as well as the material of the packaging material, the external temperature and humidity of the storage environment, and the type, shape and amount of the desiccant, etc. Therefore, it is difficult to estimate and enclose an appropriate amount of desiccant from the start of storage and form the package. In particular, the water vapor transmission rate of the packaging material changes under the influence of the temperature and humidity of the surrounding environment, and the degree varies depending on the material of the packaging material, which makes it more difficult to enclose an appropriate amount of desiccant. However, by using the following formula, when manufacturing a package containing a desiccant, the water vapor transmission rate of the packaging material, the surface area of the package, and the amount of desiccant can be controlled within a predetermined range, and it becomes easier to control the rate of change of the dew point inside the storage environment with respect to the external environment (dew point change rate). First, the amount of water vapor that can penetrate into the package is represented by the water vapor transmission rate (WVTR) × the surface area of the package × the number of storage days. Here, considering that WVTR changes under the influence of the temperature and humidity of the surrounding environment, the amount of water vapor that can penetrate into the package can be simply expressed by the following formula using the water vapor transmission rate at a measurement temperature of 40 °C and a measurement humidity of 90% Rh (dew point of about 38 °C dp). (WVTR [g / (m 2 × 24hr)] × the surface area of the package [m 2 ) × (the external dew point of the storage environment [°C dp] / 38) × (the external temperature of the storage environment [°C] / 40) × the number of storage days Next, the maximum amount of moisture that can be removed from inside the package by the desiccant is affected by factors such as the type, shape and amount of the desiccant, but can be simply expressed by the following formula. 0.26 × the amount of desiccant enclosed [g] At this time, it is preferable that the amount of water vapor that can penetrate into the package is less than or equal to the maximum amount of moisture that can be removed from inside the package by the desiccant, that is, the following formula is satisfied. (WVTR [g / (m 2 × 24hr)] × the surface area of the package [m 2) × (External dew point of the storage environment [°C dp] / 38) × (External temperature of the storage environment [°C] / 40) × Number of storage days ≤ 0.26 × Amount of desiccant enclosed [g] Furthermore, in the above formula, when the external environmental temperature is 30 °C, the external dew point of the storage environment is 24 °C dp, and the number of storage days is 180 days, it is preferable to adjust the amount of desiccant so that the value obtained by the following formula (2) satisfies 0.0030 or less. Thereby, an appropriate amount of desiccant can be enclosed according to the configuration of the package, and it becomes easier to control the dew point change in the storage environment. WVTR [g / (m 2 × 24hr)] × Surface area of the package [m 2 / Amount of desiccant enclosed [g] ···(2) However, when the package is composed of two or more packaging materials with different water vapor transmission rates, "WVTR [g / (m 2 × 24hr)] × Surface area of the package [m 2 " in formula (2) is the sum of the values calculated for each packaging material as "WVTR [g / (m 2 × 24hr)] × Surface area of the package [m 2 ". The value obtained by formula (2) is more preferably 0.0023 or less, still more preferably 0.0012 or less, particularly preferably 0.0005 or less. The value obtained by formula (2) may be 0.

[0037] In the present disclosure, the dew point change rate in the package having a desiccant inside is defined by the following formula. Dew point change rate = (Dew point of the storage environment after 365 days of storage (°C dp) - Initial dew point of the storage environment (°C dp)) / (Average external dew point of the packaging material (°C dp) - Dew point of the storage environment after 365 days of storage (°C dp)) The smaller the value of the dew point change rate in the package, the greater the effect of controlling the storage environment by the packaging material and the desiccant. The dew point change rate in the package is evaluated by the above formula, and the dew point change rate in the package 365 days after starting the storage of the glass cloth, starting from the start date of storage, is preferably 3.0 or less, more preferably 1.0 or less, still more preferably 0.50 or less, even more preferably 0.30 or less, particularly preferably 0.10 or less, or 0.02 or less. The dew point change rate may be a negative value.

[0038] <Dry gas> When using dry gas for dew point control, it is preferable to use a gas (dry gas) with a dew point temperature of 18°C dp or lower. With such a dry gas, it is easy to control the average dew point of the storage environment of the glass cloth to be an atmosphere of 18°C dp or lower. The dew point temperature of the dry gas is preferably -60°C dp or higher and 18°C dp or lower. The lower limit value of the dew point temperature of the dry gas may be more preferably -50°C dp or higher, -40°C dp or higher, -30°C dp or higher. The upper limit value of the dew point temperature of the dry gas may be more preferably 15°C dp or lower, 10°C dp or lower, 5°C dp or lower, 0°C dp or lower, -5°C dp or lower, -10°C dp or lower, -15°C dp or lower, -20°C dp or lower, or -21°C dp or lower.

[0039] As the dry gas, for example, dry air within the above dew point temperature range, or a gas containing at least one selected from the group consisting of nitrogen, argon, and oxygen within the above dew point temperature range can be used. It is preferable to use dry air for ease of handling.

[0040] When using a dehumidifier for dew point control, the dehumidifier is not limited as long as it can control the average dew point within the above range. For example, a compressor type that utilizes condensation at low temperatures, a desiccant type (zeolite type) that regenerates the desiccant with heat multiple times, etc. can be mentioned.

[0041] When suppressing the change in dew point over time, it is preferable to store the glass cloth in a sealed storage environment. As the sealing method, it is particularly preferable that the inflow of moisture into the storage environment is suppressed. Specific storage forms will be described later.

[0042] <Average temperature in the storage environment of the glass cloth> The glass cloth is stored in an atmosphere where the average temperature of the storage environment of the glass cloth is 100°C or lower. When the average temperature is 100°C or lower, it is possible to effectively suppress the increase in the dielectric loss tangent of the glass cloth over time. The average temperature of the storage environment of the glass cloth when storing the glass cloth is preferably 0°C or higher and 100°C or lower. The upper limit value of the average temperature is preferably 50°C or lower, more preferably 40°C or lower, still more preferably 35°C or lower, even more preferably 30°C or lower, and particularly preferably 25°C or lower. The lower limit value of the average temperature may be preferably 10°C or higher, or 20°C or higher. Preferably, the temperature of the storage environment is controlled to be 100°C or lower throughout the entire storage period. More preferably, it is controlled to a temperature of 40°C or lower, still more preferably 35°C or lower, even more preferably 30°C or lower, and particularly preferably 30°C or lower throughout the entire storage period. Preferably, the temperature of the storage environment is controlled to be 0°C or higher, 10°C or higher, or 20°C or higher throughout the entire storage period.

[0043] 〈Pressure in the storage environment of the glass cloth〉 When depressurization is performed for dew point control, it is preferably controlled to be under a reduced pressure of less than atmospheric pressure (10 5 Pa). The method of controlling the atmospheric pressure of the storage environment of the glass cloth to be under a reduced pressure of less than atmospheric pressure is not limited as long as the average dew point can be controlled within the above range, but known pressure reduction control methods, pressure reduction control media, pressure reduction control mechanisms, and pressure reduction control devices, etc. can be used, and for example, a vacuum pump can be mentioned.

[0044] The maintenance of the atmospheric pressure can be performed by known methods as long as the storage environment of the glass cloth is maintained under a reduced pressure of less than atmospheric pressure. For example, the storage environment can be depressurized continuously or intermittently (regularly or irregularly), or the glass cloth can be sealed in a depressurized packaging material (packaging material) to suppress changes in atmospheric pressure, etc. The atmospheric pressure around the glass cloth when storing or packaging (packing) the glass cloth is preferably 10 4 Pa or lower, more preferably 10 3It is below Pa. The lower limit value of the air pressure is not particularly limited, but is preferably more than 0 Pa, or 10 Pa or more.

[0045] 〈Storage form〉 The storage form of the glass cloth is not particularly limited as long as the above storage environment is maintained. For example, storage in a room such as a storage room, storage in a package (packaged body) wrapped (packed) with a packaging material (packaging material), and combinations thereof can be mentioned. In the present disclosure, the terms "packaging" and "packing" are used interchangeably as terms meaning to wrap an object. Examples of the packaging material include a box and a film. In each case, it is preferable to control the storage environment, that is, the average dew point, temperature, and optionally the pressure of the atmosphere in direct contact with the glass cloth, within the above ranges. Further, from the viewpoints of avoiding wrinkles in the glass cloth and reducing the storage space, the glass cloth is preferably stored in a roll state. In the roll state, it is easy to minimize the area where the storage environment contacts the external environment and to reduce the internal air volume during packaging, and it is possible to more effectively suppress the increase in the dielectric tangent over time.

[0046] Regarding the storage room for storing the glass cloth and the packaging material, from the perspective of facilitating the maintenance of the average dew point and temperature, it is preferable that the sealing performance is high. In addition to or instead of having high sealing performance, the storage room and the packaging material are preferably configured to dehumidify so as to maintain the average dew point of the interior (storage environment) at 18°C dp or lower. That is, it is preferable that the dew point control means as described above is provided in the storage room and the packaging body itself. The average dew point of the interior (storage environment) is preferably -50°C dp or higher and 18°C dp or lower. The lower limit value of the average dew point of the interior (storage environment) may be more preferably -40°C dp or higher, -32°C dp or higher, -30°C dp or higher, -20°C dp or higher, -10°C dp or higher, 0°C dp or higher, 10°C dp or higher, or 13°C dp or higher. The upper limit value of the average dew point of the interior (storage environment) that can be arbitrarily combined with the above lower limit value may be more preferably 15°C dp or lower, 10°C dp or lower, 5°C dp or lower, 0°C dp or lower, -5°C dp or lower, -10°C dp or lower, -15°C dp or lower, -20°C dp or lower, or -21°C dp or lower.

[0047] 〈Packaging Material〉 From the perspective of facilitating the maintenance of the dew point of the storage environment, the water vapor permeability of the packaging material (such as boxes and films) at a measured temperature of 40°C and a measured humidity of 90% Rh is preferably 8 g / (m 2 ×24 hr) or less, more preferably 4 g / (m 2 ×24 hr) or less, still more preferably 2 g / (m 2 ×24 hr) or less, even more preferably 1 g / (m 2 ×24 hr) or less, particularly preferably 0.3 g / (m 2 ×24 hr) or less, and particularly preferably 0.1 g / (m 2 ×24 hr) or less. When the water vapor permeability of the packaging material is 8 g / (m 2 ×24 hr) or less, the amount of moisture permeating is reduced, and it is easy to control the dew point. The lower limit value of the water vapor permeability is 0 g / (m 2 ×24 hr) or more, for example, exceeding 0 g / (m 2 ×24 hr).

[0048] When storing the glass cloth in the state of a roll as a package wrapped with a box and / or a film-like packaging material, it is preferable to enclose a moisture absorbent in the package. It is more preferable to enclose the moisture absorbent between the roll and the packaging material. Thereby, it is possible to absorb the moisture inside the package, and also to absorb the moisture that has permeated through the box and / or the film-like packaging material during storage and flowed into the storage environment.

[0049] From the viewpoint of facilitating the maintenance of the dew point and temperature, it is preferable that the glass cloth is wrapped with a box and / or a film-like packaging material and its opening is sealed. The sealing can be performed, for example, by thermocompression bonding the opening. Here, the sealing means a state in which the opening is firmly closed without gaps and the temperature, dew point, and atmospheric pressure in the storage environment of the glass cloth can be controlled below a certain standard. Also, the sealed state is preferably to seal so as to prevent the intrusion of solids, liquids, and gases. By suppressing the intrusion of solids, liquids, and gases, the effect of suppressing the increase in the dielectric tangent of the glass cloth can be easily obtained.

[0050] When using a box as the packaging material, the box is not limited as long as its water vapor permeability satisfies the above range, but it is a specification that can seal the opening. Examples include metal boxes, plastic boxes, wooden boxes, cardboard boxes, or boxes combined thereof. From the viewpoint of easily satisfying the above range of water vapor permeability and easy reusability, the material is preferably metallic or plastic, and more preferably metallic. Here, the box refers to a movable and airtight container for blocking the glass cloth from the outside air. One or more glass cloths may be stored in the box.

[0051] When using a film as the packaging material, the film is not limited as long as the water vapor permeability satisfies the above range. Examples include ceramic vapor deposition films, aluminum vapor deposition films, aluminum foils, aluminum laminated films, etc. From the perspective of easily satisfying the above range of water vapor permeability, aluminum foils and aluminum laminated films are preferred. Also, the thickness of the film is preferably 30 μm or more and 500 μm or less. The lower limit value of the film thickness is preferably 50 μm or more, more preferably 70 μm or more, still more preferably 80 μm or more, and particularly preferably 90 μm or more. When the thickness is 50 μm or more, the water vapor permeability tends to be small, and pinholes due to wrinkles, scratches, etc. are less likely to occur. The upper limit value of the film thickness is preferably 400 μm or less, 300 μm or less, 200 μm or less, or 170 μm or less.

[0052] The glass cloth is also referred to as a roll (simply "glass cloth roll") wound around a hollow columnar core tube having a columnar cavity (hollow part) at the center. It is preferably stored as a packaged body wrapped in a film. When handling the glass cloth roll during transportation, etc., a support rod is often inserted into the hollow part of the core tube of the roll to lift the roll. From the perspective of maintaining the above storage environment, it is preferable to package the glass cloth roll with a packaging material having a minimum surface area. However, in that method, the hollow part of the core tube cannot be utilized during the handling of the glass cloth roll, and the handling becomes complicated. Therefore, from the perspective of ease of handling the glass cloth roll, the glass cloth roll preferably has a film-like packaging material having a recess extending into the hollow part from one end or both ends of the core tube, or the film-like packaging material is annular (doughnut-shaped) passing through the hollow part of the core tube so that a support rod can be inserted into the hollow part of the core tube. Alternatively, from the perspective of ease of handling the glass cloth roll, it is preferable that the glass cloth is sealed from the external environment by a film-like packaging material and a core tube.

[0053] FIG. 1 is a schematic diagram showing an axial cross section of the core tube of the glass cloth package of the present disclosure. For example, as schematically shown in FIG. 1(1a), the glass cloth package 10 may include a hollow columnar core tube 11, a glass cloth 12 wound around the core tube 11, and a film 13 surrounding the entire core tube 11 and the glass cloth 12. The film 13 is configured such that a support rod can be inserted into the hollow portion by having a recess 14 from one end of the core tube 11 toward the inside of the hollow portion. Further, as schematically shown in FIG. 1(1b), the glass cloth package 10 has an outer film 13a covering the outside of the glass cloth 12 and a hollow inner film 13b penetrating through the inside of the hollow portion of the core tube 11, and the outer film 13a and the inner film 14b may be joined at a joint 15 by thermocompression bonding or the like. Thereby, the films 13a and 13b integrally have an annular form surrounding the entire core tube 11 and the glass cloth 12. When the packaging material is annular, the external environment penetrates the hollow portion of the core tube, so that a support rod can be penetrated into the hollow portion from both sides of the package, and the handleability is further improved. The joining of the films is not particularly limited as long as the openings can be brought into close contact with each other to eliminate gaps. For example, methods such as thermocompression bonding, taping, and applying an adhesive can be mentioned. Alternatively, as schematically shown in FIG. 1(1c), the film 13 covering the outside of the glass cloth 12 and the core tube 11 may be joined at a joint 15 located on the exposed outer surface of the core tube 11. Thereby, the glass cloth 12 is sealed from the external environment by the film 13 and the core tube 11. In this form, since the external environment penetrates the hollow portion of the core tube, a support rod can be penetrated into the hollow portion from both sides of the package, and since there is no film inside the core tube, pinholes or the like are less likely to occur when the support rod is inserted and removed and when the roll is lifted and transported, and the handleability is further improved. The joining of the film-shaped packaging material and the core tube is not particularly limited as long as the openings can be brought into close contact with each other to eliminate gaps. For example, methods such as taping or applying an adhesive to the openings can be mentioned.

[0054] From the perspective of easy insertion of the support rod, among the volume of the hollow part of the core tube, the proportion of the volume occupied by the space inside the film-like package is preferably 70% or less, more preferably 50% or less, even more preferably 30% or less, and particularly preferably 10% or less. The lower limit of the volume inside the package with respect to the volume of the hollow part may be 0% or more. For example, in the form schematically shown in Fig. 1(1c), the volume inside the package with respect to the volume of the hollow part is 0%.

[0055] 〈Core tube〉 The core tube around which the roll-shaped glass cloth is wound has a columnar cavity (hollow part) in the center from the perspective of its transportation and handling properties during post-processing. Examples of the material of the core tube include paper, resin, fiber reinforced plastics (hereinafter referred to as "FRP"), and metal. From the perspective of preventing the mixing of metal foreign substances into the glass cloth, paper, resin, and FRP are preferred. Generally, the core tube has a certain thickness from the perspective of the balance between weight and strength. In particular, for the glass cloth roll, while the weight of the glass cloth itself is large, in the case of a core tube with a small diameter, strong bending is applied to the glass cloth, so the diameter of the core tube has been increased and the weight has been reduced. Since the core tube is thicker than a film or the like, water vapor transmission through the core tube has not been considered so far. However, as a result of the study, it was found that water vapor can permeate even through paper, resin, and FRP core tubes due to the fact that the overall thickness of the core tube is thin to reduce its weight, the core tube is composed of a combination of thin materials, and there are joints when combining the materials. Therefore, it is preferable to use a core tube with a low water vapor transmission rate.

[0056] From the perspective of easy control of the moisture content inside the packaging material, the water vapor transmission rate of the core tube measured under the conditions of 40°C and 90% Rh is preferably 8 g / (m 2 ×24 h) or less, more preferably 4 g / (m 2 ×24 h) or less, even more preferably 2 g / (m 2 ×24 h) or less, still more preferably 1 g / (m 2 ×24 h) or less, and particularly preferably 0.3 g / (m2 ×24 hr) or less, particularly preferably 0.1 g / (m 2 ×24 hr) or less. When the water vapor permeability of the core tube is 8 g / (m 2 ×24 hr) or less, the amount of permeating moisture is reduced, and it is easy to control the dew point. The lower limit value of the water vapor permeability is 0 g / (m 2 ×24 hr) or more, for example, more than 0 g / (m 2 ×24 hr). As a method for controlling the water vapor permeability of the core tube within the above range, methods such as applying a moisture-proof paint to the core tube, performing vapor deposition plating, increasing the thickness of the core tube, using a material with low water vapor permeability for the core tube, and winding a film with low water vapor permeability around the core tube can be mentioned.

[0057] 〈Surface area of the package〉 The smaller the surface area of the glass cloth package wrapped by the packaging material, the easier it is to maintain the storage environment. The surface area of the package is not limited as long as the dew point of its storage environment satisfies the range of the present disclosure, but is preferably 10 m 2 or less, more preferably 7 m 2 or less, still more preferably 5 m 2 or less, even more preferably 4 m 2 or less. The lower limit value of the surface area of the package is not limited as long as the glass cloth can be sealed from the external environment. In the present disclosure, the "surface area of the package" means, for example, the area of the film when the glass cloth is sealed from the external environment by the film, the outer surface area of the box when the glass cloth is sealed from the external environment by the box, and the sum of the area of the film and the outer diameter side surface area of the core tube separating the external environment and the storage environment when the glass cloth is sealed from the external environment by the film and the core tube.

[0058] 〈Storage room〉 The storage room for storing the glass cloth means an indoor space where the dew point and temperature are controlled. From the perspective of space saving, it is preferable that the glass cloth is stored indoors in a rolled state and a plurality of glass cloths are stored together. The glass cloth in a rolled state may be stored in the storage room as a package wrapped with a box and / or a film-like packaging material.

[0059] "Method for Manufacturing Glass Cloth" The method for manufacturing a glass cloth used in the method for storing the glass cloth of the present disclosure includes a step of weaving a glass yarn containing a plurality of glass filaments as warp and weft to obtain a glass cloth. The method for manufacturing a glass cloth can further include a step of subjecting the glass yarn or the glass cloth to heat degreasing treatment (heat cleaning), and a step of treating the glass yarn or the glass cloth with a surface treatment agent. The method for manufacturing a glass cloth may optionally further include at least one of a step of opening the glass cloth and a step of packaging the glass cloth with a packaging material (such as a box and a film).

[0060] 〈Weaving Step〉 The weaving method is not particularly limited as long as the weft and the warp can be woven into a predetermined weaving structure. The preferred configuration and composition of the glass yarn to be used, as well as the weaving structure, are as described above.

[0061] 〈Heat Degreasing Step〉 The heat degreasing step can be performed on the glass yarn, or can also be performed on the woven glass cloth. In other words, the step of weaving the glass yarn to obtain a glass cloth may be performed before, during, or after the heat degreasing step. The heat degreasing step can use either (1) a method of heating and degreasing the glass yarn or the glass cloth (hereinafter, also simply referred to as "glass" in this step) at a relatively low temperature (for example, less than 600°C) for a long time (for example, 24 hours or more), or (2) a method of heating and degreasing the glass at a relatively high temperature (for example, 600°C to 1600°C) for a long time or a short time (for example, less than 24 hours). From the viewpoint of obtaining a glass cloth having an excellent dielectric tangent, it is preferable to use the method (2). In particular, a glass cloth composed of a glass yarn having a Si content of 95.0 mass% or more and 100 mass% or less in terms of SiO2 may be heat degreased at a temperature of 600°C or higher. Thereby, it is easy to lower the dielectric tangent of the glass cloth.

[0062] (1) When heating at a relatively low temperature, the temperature for heat degreasing is preferably 100°C or higher and 500°C or lower, more preferably 250°C or higher and 450°C or lower, still more preferably 350°C or higher and 450°C or lower. Also, the heating time for heat degreasing in the case of (1) can be appropriately selected. For example, it is preferably 24 hours or more and 300 hours or less, more preferably 48 hours or more and 200 hours or less, still more preferably 72 hours or more and 150 hours or less. If the combination of the heat degreasing temperature and time is within the above range, it is easy to sufficiently remove the paste adhering to the glass.

[0063] On the other hand, (2) when heating at a relatively high temperature, the temperature for heat degreasing is preferably 600°C or higher and 1500°C or lower, more preferably 800°C or higher and 1300°C or lower, still more preferably 900°C or higher and 1100°C or lower. If the heat degreasing temperature is 600°C or higher, it is easy to sufficiently remove organic substances such as residues of the paste adhering to the glass, so it is easy to lower the dielectric tangent of the glass cloth, and the removal time can be shortened. On the other hand, if the heat degreasing temperature is 1500°C or lower, it is easy to suppress the devitrification phenomenon of the glass, and the strength reduction of the glass cloth can be effectively prevented. Also, the heating time for heat degreasing in the case of (2) can be appropriately selected. For example, it is preferably 3 seconds or more and 72 hours or less, more preferably 3 seconds or more and 12 hours or less, still more preferably 3 seconds or more and 2 hours or less, particularly preferably 3 seconds or more and 10 minutes or less, particularly preferably 3 seconds or more and 300 seconds or less.

[0064] As the heating means for heat degreasing, known heating methods, heating media, heating mechanisms, heating devices, heating parts, etc. can be used as long as the heat degreasing temperature can be suitably controlled. For example, (1) a method of heating the glass in a heating furnace, (2) a method of bringing the glass into contact with a heating part, (3) a method of applying high-temperature steam to the glass, etc. may be used. The heating can be carried out sequentially or continuously, in a closed system or an open system, or a combination of a closed system and an open system can be used.

[0065] In the case of a closed system, from the perspective of suitable heating by heating means, it is preferable to place the glass in a heating furnace. At this time, from the perspectives of the storage space and the heating range, it is preferable to heat the glass while storing it in the form of a roll of glass cloth. Further, from the perspectives of increasing the removal efficiency of organic substances and shortening the removal time of organic substances, etc., it is also preferable to heat the glass while conveying it in the heating furnace.

[0066] In the case of an open system, from the perspective of the heated area, it is preferable to heat the glass while conveying it in a Roll-to-Roll manner. As described above, the heating temperature is preferably 600°C or higher and 1500°C or lower, more preferably 800°C or higher and 1300°C or lower, and still more preferably 900°C or higher and 1100°C or lower. The conveyance of the glass can be performed, for example, by an unwinding mechanism and a winding mechanism.

[0067] Examples of the heating means of the heating furnace include various ones such as electric heaters and burners, and a gas single radiant tube burner or an electric heater is preferable. Multiple means may be combined for heating.

[0068] From the perspective of heating efficiency, the heating furnace preferably includes means for discharging the gas generated in the heating furnace and / or air circulation means. The gas discharge means may be a nozzle, a gas pipe, a small hole, a gas bleed valve, etc. The air circulation means may be a fan, air conditioning equipment, etc.

[0069] The heating furnace may be of either a batch type that can accommodate the glass (for example, a roll of glass cloth) and heat it at a predetermined ambient temperature, or a continuous type that can continuously heat the glass while passing it through the heating furnace (for example, heat it while conveying it in a Roll-to-Roll manner). In order to efficiently remove the organic substances adhering to the glass surface, the continuous type is preferable for the heating furnace.

[0070] As a method for heating the glass, the above heating furnace may be used, but from the perspective of low running costs, heating may also be performed by bringing a member heated to a predetermined temperature into contact with the glass.

[0071] If heating can be carried out while suitably controlling the heating and degreasing temperature, the shape of the contact member is not particularly limited, but a roll shape is preferable (heating roll method) from the viewpoint of ease of transporting the glass. As a member capable of heating the glass in a roll shape, a roll heated by an induction heating method, which can be used in a high-temperature region and has relatively little variation in temperature in the width direction, is preferable. When heating the glass with the contact member, it is considered that the temperature of the contact member and the surface temperature of the glass are generally equal.

[0072] As the glass is continuously heated, carbides may adhere to the heating roll. In order to remove the carbides adhering to the heating roll, it is preferable that the above heating roll method is provided with a mechanism for removing the adhered foreign matter, for example, a mechanism such as a blade.

[0073] <Surface treatment step> The surface treatment step can be performed on the glass yarn, and can also be performed on the woven glass cloth. In other words, the step of weaving the glass yarn to obtain the glass cloth may be performed before, during, or after the surface treatment step. The surface treatment step can have, for example, a coating step of adhering a silane coupling agent to the surface of the glass yarn or the glass cloth (hereinafter, also simply referred to as "glass" in this step) with a treatment liquid having a concentration of 0.1% by mass to 0.5% by mass. The surface treatment step can further have a fixing step of fixing the silane coupling agent to the surface of the glass by heating and drying. Thereby, it becomes easier to suitably surface-treat the glass.

[0074] As a method of applying a treatment liquid to glass in the coating process, there are, for example, (a) a method of immersing or passing glass through the treatment liquid stored in a bath (hereinafter referred to as the "immersion method"), (b) a method of applying the treatment liquid to glass using a roll coater, a die coater, a gravure coater, or the like. When adopting the immersion method, it is preferable to select the immersion time of the glass in the treatment liquid to be 0.5 seconds or more and 1 minute or less. Further, when adopting the immersion method, while applying a predetermined tension (for example, 100 N to 250 N) to the glass, the glass can be passed through the treatment liquid at a conveyance speed of 10 m / min to 50 m / min. Further, after applying the treatment liquid to the glass, the solvent contained in the treatment liquid can be heated and dried by a method such as hot air or electromagnetic waves. In order to facilitate the uniform coating of the surface treatment agent on the glass surface, it is preferable to immerse the glass cloth in the surface treatment liquid and then squeeze it up with a constant pressure using a rubber roller.

[0075] The concentration of the surface treatment agent in the treatment liquid is preferably 0.1% by mass to 0.5% by mass, more preferably 0.1% by mass to 0.45% by mass, and still more preferably 0.1% by mass to 0.4% by mass based on the total mass of the treatment liquid. According to this, it becomes easier to surface-treat the glass more suitably.

[0076] In the fixing process, the heat-drying temperature is preferably 80°C or higher, more preferably 90°C or higher, so that the reaction between the silane coupling agent and the glass proceeds sufficiently. Further, the heat-drying temperature is preferably 300°C or lower, more preferably 180°C or lower, in order to prevent the deterioration of the organic functional groups of the silane coupling agent.

[0077] 〈Fibrillation process〉 The method for manufacturing a glass cloth may further include a step of fibrillating the glass cloth. As a fibrillating method in the fibrillation step of the glass cloth, for example, a method of fibrillating the glass cloth by spray water (high-pressure water fibrillation), a vibro washer, ultrasonic water, a mangle, or the like can be adopted. In many cases, the composition of the glass cloth usually does not change before and after fibrillation.

[0078] 〈Packaging process〉 The method for manufacturing a glass cloth may further include a step of packaging the glass cloth with a packaging material, such as a film or a box. This makes it easier to maintain the storage environment of the glass cloth. Since the details of the packaging material have been described above, the description is omitted here. In the packaging step, it is preferable to control in advance the dew point, temperature, and optionally pressure, etc. of the environment in direct contact with the glass cloth to the storage environment of the present disclosure before packaging. Since the storage environment has been described above, the description is omitted here. Also, as a sealing method, for example, a method of wrapping the glass cloth with a film and thermocompression bonding the opening, a method of putting the glass cloth in a box, making the opening in close contact to eliminate gaps, a method of pasting the opening with a tape, etc. can be used.

[0079] When packaging a glass cloth in the form of a roll wound around a hollow columnar core tube with a film, for example, covering the glass cloth roll with a film, thermocompression bonding the opening to seal it, and pushing the excess film into the hollow part from one end or both ends of the core tube, etc., a recess extending into the hollow part from one end or both ends of the core tube can be formed. As a method of packaging in an annular shape with the hollow part of the core tube penetrating, inserting a tubular film into the hollow part of the core tube of the glass cloth roll, covering the glass cloth roll with another film, and thermocompression bonding the tubular film and the tubular film penetrating the hollow part to seal the opening, etc. can be mentioned. As a method of joining and packaging the film and the core tube, for example, pasting the film onto the surface of the core tube with a tape without gaps, etc. can be mentioned.

[0080] The above steps do not necessarily have to be carried out in a manner distinguishable as separate steps, and a plurality of steps can also be carried out together (simultaneously). Also, the method for manufacturing a glass cloth can have arbitrary steps other than the above steps. For example, after the fibrillation step, a slitting step can be included. Also, if possible, the order of the above steps can be changed.

[0081] 《Glass Cloth Package》 The glass cloth package of the present disclosure includes a packaging material and a glass cloth stored inside the packaging material. The glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft, and has a dielectric tangent at 10 GHz of 0.00200 or less. And the packaging material storing the above glass cloth is sealed, and the water vapor permeability at a measurement temperature of 40 °C and a measurement humidity of 90%Rh of the packaging material is 8 g / (m 2 ×24 hr) or less. Conventionally, in the temperature range below 100 °C, since the reaction in which the Si-O-Si bond is cleaved by moisture to generate Si-OH groups is not activated, in the temperature range below 100 °C, even if a glass cloth having a dielectric tangent at 10 GHz of 0.00200 or less is stored for a long time, it has been considered that the dielectric tangent of the glass cloth does not change with time. Therefore, no special consideration has been given to the storage form of the glass cloth, and even a glass cloth having a low dielectric tangent at the time of manufacture may have its dielectric tangent increase over time. In this regard, the glass cloth package of the present disclosure can suppress the increase in the dielectric tangent of the glass cloth over time because the cleavage of the Si-O-Si bond by moisture that has invaded the storage environment from the external environment to generate Si-OH groups is suppressed. In the present disclosure, "suppression" does not mean that the dielectric tangent does not increase at all, and it is sufficient that the increase in the dielectric tangent is suppressed to a certain extent.

[0082] 〈Glass Cloth〉 Regarding the details of the glass cloth, the dielectric tangent of the glass cloth, the glass yarn, the silane coupling agent, and the loss on ignition value in the glass cloth package, since they are as described in 〈Glass Cloth〉~〈Loss on Ignition Value〉 of the above-mentioned 《Method for Storing Glass Cloth》, these descriptions are incorporated by reference for the glass cloth package.

[0083] 〈Packaging Material〉 The packaging material can store and seal the glass cloth. The water vapor permeability of the packaging material (such as a box and a film) measured under the conditions of 40 °C and 90%Rh is 8 g / (m 2It is below ×24 hr). Sealing means that the opening is firmly closed without gaps and the temperature, dew point, and air pressure in the glass cloth package can be controlled below a certain standard. Also, the sealed state preferably means sealing to prevent the intrusion of solids, liquids, and gases. By suppressing the intrusion of solids, liquids, and gases, the effect of suppressing the increase in the dielectric tangent of the glass cloth described in the present disclosure is easily obtained. The packaging material is not limited as long as it satisfies the above configuration, and examples include films and box-shaped packaging materials.

[0084] 〈Water vapor permeability〉 The packaging material has a water vapor permeability at a measurement temperature of 40 °C and a measurement humidity of 90% Rh of 8 g / (m 2 ×24 hr) or less. With such a packaging material, the amount of moisture inside the packaging material can be controlled, and an increase in the dielectric tangent of the glass cloth over time due to the water present in the packaging material can be suppressed. From the viewpoint of easily controlling the amount of moisture inside the packaging material, the water vapor permeability of the packaging material at a measurement temperature of 40 °C and a measurement humidity of 90% Rh is preferably 8 g / (m 2 ×24 hr) or less, more preferably 4 g / (m 2 ×24 hr) or less, still more preferably 2 g / (m 2 ×24 hr) or less, even more preferably 1 g / (m 2 ×24 hr) or less, particularly preferably 0.3 g / (m 2 ×24 hr) or less, most preferably 0.1 g / (m 2 ×24 hr) or less. When the water vapor permeability of the packaging material is 8 g / (m 2 ×24 hr) or less, the amount of permeating moisture decreases, and it is easy to control the amount of moisture inside the packaging material. The lower limit value of the water vapor permeability is 0 g / (m 2 ×24 hr) or more, for example, more than 0 g / (m 2 ×24 hr).

[0085] 〈Film〉 As the packaging material, a film can also be used. Although not limited as long as the water vapor transmission rate satisfies the above range, examples include a ceramic vapor-deposited film, an aluminum vapor-deposited film, an aluminum foil, an aluminum laminated film, etc. From the viewpoint of easily satisfying the above range of water vapor transmission rate, an aluminum foil and an aluminum laminated film are preferable. Also, the thickness of the film is preferably 30 μm or more and 500 μm or less. The lower limit value of the film thickness is preferably 50 μm or more, more preferably 70 μm or more, still more preferably 80 μm or more, and particularly preferably 90 μm or more. When the thickness is 50 μm or more, the water vapor transmission rate tends to be small, and pinholes due to wrinkles, scratches, etc. are less likely to occur. The upper limit value of the film thickness is preferably 400 μm or less, 300 μm or less, 200 μm or less, or 170 μm or less.

[0086] The glass cloth is also referred to as a roll (simply "glass cloth roll") wound around a hollow columnar core tube having a columnar cavity (hollow part) at the center. It is preferably a package wrapped in a film in a () state. For the same reasons described in <Packaging Material> of the above-mentioned <Method for Storing Glass Cloth>, the film has a recess extending into the hollow part from one end or both ends of the core tube, or the film-shaped packaging material is annular (doughnut-shaped) penetrating the hollow part of the core tube, so that it is preferably configured to allow a support rod to be inserted into the hollow part of the core tube. Alternatively, it is preferable that the glass cloth is sealed from the external environment by a film-shaped packaging material and a core tube. Specific examples of these are schematically shown in FIGS. 1(1a) to (1c) as described above.

[0087] From the viewpoint of easy insertion of the support rod, the ratio of the volume occupied by the space inside the film-shaped package to the volume of the hollow part of the core tube is preferably 70% or less, more preferably 50% or less, still more preferably 30% or less, and particularly preferably 10% or less. The lower limit value of the volume inside the package with respect to the volume of the hollow part may be 0% or more. For example, in the form schematically shown in FIG. 1(1c), the volume inside the package with respect to the volume of the hollow part is 0%.

[0088] <Core tube> For the same reasons as described in the <Core tube> of the above-mentioned "Method for Storing Glass Cloth", the material of the core tube is preferably made of paper, resin, or FRP. In addition, the water vapor permeability of the core tube measured under the conditions of 40 °C and 90% Rh is preferably 8 g / (m 2 × 24 h) or less, more preferably 4 g / (m 2 × 24 h) or less, even more preferably 2 g / (m 2 × 24 h) or less, still more preferably 1 g / (m 2 × 24 h) or less, particularly preferably 0.3 g / (m 2 × 24 h) or less, particularly preferably 0.1 g / (m 2 × 24 h) or less. The lower limit value of the water vapor permeability is 0 g / (m 2 × 24 h) or more, for example, more than 0 g / (m 2 × 24 h).

[0089] <Box-shaped packaging material> As the packaging material, box-shaped ones can also be used. Although not limited as long as the water vapor permeability satisfies the above range, it is a specification that can seal the opening, and examples include metal, plastic, wooden, cardboard boxes, or boxes combined thereof. From the viewpoint of easily satisfying the above range of water vapor permeability and easy reuse, the material is preferably metallic or plastic, and more preferably metallic. Here, the box refers to a movable, airtight container for blocking the glass cloth from the outside air. One or more glass cloths may be stored in the box.

[0090] <Surface area of the package> For the same reasons as described in the <Core tube> of the above-mentioned "Method for Storing Glass Cloth", the surface area of the package is not limited as long as the dew point of the storage environment satisfies the scope of the present disclosure, but is preferably 10 m 2 or less, more preferably 7 m 2 or less, even more preferably 5 m 2 or less, still more preferably 4 m 2The following is the case. The lower limit value of the surface area of the package is not limited as long as the glass cloth can be sealed from the external environment.

[0091] 〈Dew point inside the glass cloth package〉 For the glass cloth package, it is preferable that the dew point under the atmospheric pressure inside the packaging material is 18 °C dp or less. In the present disclosure, unless otherwise specified, the dew point refers to the dew point under the atmospheric pressure of the storage environment. When the dew point under the atmospheric pressure inside the packaging material is 18 °C dp or less, it is possible to more effectively prevent the increase in the dielectric loss tangent of the glass cloth over time. The dew point is preferably -50 °C dp or more and 18 °C dp or less. The lower limit value of the dew point may be more preferably -40 °C dp or more, -32 °C dp or more, -30 °C dp or more, -20 °C dp or more, -10 °C dp or more, 0 °C dp or more, 10 °C dp or more, or 13 °C dp or more. The upper limit value of the dew point that can be arbitrarily combined with the above lower limit value may be more preferably 15 °C dp or less, 10 °C dp or less, 5 °C dp or less, 0 °C dp or less, -5 °C dp or less, -10 °C dp or less, -15 °C dp or less, -20 °C dp or less, or -21 °C dp or less.

[0092] As a method for controlling the dew point within the above range, known humidity control methods, humidity control media, humidity control mechanisms, and humidity control devices can be used. For example, (1) using a desiccant, (2) replacing the atmosphere inside the packaging material with a gas having a predetermined moisture content (for example, dry gas), (3) dehumidifying the atmosphere inside the packaging material by utilizing condensation at a low temperature, (4) reducing the pressure to make the atmosphere inside the packaging material have a predetermined moisture content, and (5) combinations thereof. For example, by performing the above controls (1) to (5) and sealing the packaging material, the effect of suppressing the increase in the dielectric loss tangent can be easily obtained.

[0093] When a dehumidifier is used for dew point control, the dehumidifier is not limited as long as it can control the dew point within the above range. For example, compressors that utilize condensation at low temperatures, desiccant (zeolite type) dehumidifiers that regenerate the desiccant with heat multiple times, etc. can be mentioned.

[0094] 〈Desiccant〉 It is preferable to enclose a moisture absorbent inside the packaging material of the glass cloth package. By doing so, it is possible to absorb moisture inside the packaging material, and also to absorb moisture that has permeated through the packaging material during storage and flowed into the inside of the packaging material.

[0095] From the viewpoint of moisture absorption capacity, the moisture absorbent is preferably at least one selected from the group consisting of silica gel, calcium oxide, calcium chloride, calcined diatomaceous earth, synthetic zeolite, clay-based desiccant, phosphorus pentoxide, magnesium sulfate, copper sulfate, magnesium chloride, cobalt chloride, granular soda lime, and magnesium perchlorate. Among these, it is preferably at least one selected from the group consisting of silica gel, calcium oxide, calcium chloride, and calcined diatomaceous earth. Also, from the viewpoints of occupied space and packaging (bundling) form, it is preferable to use a sheet-shaped moisture absorbent.

[0096] The amount of the moisture absorbent to be used is not limited, but it is preferable to use an appropriate amount according to the moisture absorption capacity (moisture absorption amount and moisture absorption time) of the moisture absorbent, the storage period, etc. Regarding the moisture absorption amount, it is preferable to use a sufficient or more amount. That is, it is preferable that the maximum moisture absorption amount that the moisture absorbent can absorb is larger than the amount of moisture in the atmosphere.

[0097] As described in the <Moisture Absorbent> of the above-mentioned <Method for Storing Glass Cloth>, the enclosed amount of the moisture absorbent is preferably a value obtained by the following formula (2) of 0.0030 or less, more preferably 0.0023 or less, still more preferably 0.0012 or less, and particularly preferably 0.0005 or less. The value obtained by the following formula (2) may be 0. WVTR [g / (m 2 ×24hr)] × package surface area [m 2 / enclosed amount of moisture absorbent [g] ···(2) {In formula (2), WVTR is the water vapor transmission rate at a measurement temperature of 40°C and a measurement humidity of 90%Rh.}

[0098] As described in <Humectant> of the above-mentioned <Method for Storing Glass Cloth>, the dew point change rate inside the package having a humectant is preferably 3.0 or less, more preferably 1.0 or less, still more preferably 0.50 or less, even more preferably 0.30 or less, particularly preferably 0.10 or less, or 0.02 or less. The dew point change rate may be a negative value.

[0099] <Dry Gas> When using a dry gas to control the dew point inside the packaging material, it is preferable to use a gas (dry gas) with a dew point temperature of 18°C dp or lower. With such a dry gas, it is easy to control the dew point inside the packaging material to be in an atmosphere of 18°C dp or lower. The dew point temperature of the dry gas is preferably -60°C dp or higher and 18°C dp or lower. The lower limit value of the dew point temperature of the dry gas may be more preferably -50°C dp or higher, -40°C dp or higher, -30°C dp or higher. The upper limit value of the dew point temperature of the dry gas may be more preferably 15°C dp or lower, 10°C dp or lower, 5°C dp or lower, 0°C dp or lower, -5°C dp or lower, -10°C dp or lower, -15°C dp or lower, -20°C dp or lower, or -21°C dp or lower.

[0100] As the dry gas, for example, dry air within the above dew point temperature range, or a gas containing at least one selected from the group consisting of nitrogen, argon, and oxygen within the above dew point temperature range can be used. It is preferable to use dry air for ease of handling.

[0101] <Temperature Inside the Glass Cloth Package> The glass cloth package preferably has a temperature of 100°C or lower in the packaging material. When the temperature is 100°C or lower, it is possible to effectively suppress the increase in the dielectric tangent of the glass cloth over time during long-term storage (for example, 30 days or more). The temperature of the glass cloth storage environment (inside the packaging material) when storing the glass cloth is preferably 0°C or higher and 100°C or lower. The upper limit value of the average temperature is preferably 50°C or lower, more preferably 40°C or lower, still more preferably 35°C or lower, even more preferably 30°C or lower, particularly preferably 25°C or lower. The lower limit value of the average temperature may be preferably 10°C or higher, or 20°C or higher.

[0102] <Pressure inside the glass cloth package> When reducing the pressure to control the dew point inside the packaging material, it is preferably controlled so that the pressure is below atmospheric pressure (10 5 Pa). The method of controlling the air pressure inside the packaging material to be under reduced pressure below atmospheric pressure is not limited as long as the dew point can be controlled within the above range, but known pressure reduction control methods, pressure reduction control media, pressure reduction control mechanisms, and pressure reduction control devices can be used. For example, a vacuum pump can be mentioned.

[0103] For example, by controlling the air pressure inside the packaging material to be under reduced pressure below atmospheric pressure and sealing the packaging material, the effect of suppressing the increase in the dielectric loss tangent can be easily obtained. The air pressure around the glass cloth when storing or packing the glass cloth is preferably 10 4 Pa or less, more preferably 10 3 Pa or less. The lower limit value of the air pressure is not particularly limited, but is preferably more than 0 Pa or 10 Pa or more.

[0104] <Storage period> The storage period of the glass cloth, that is, the period during which the sealing of the packaging material in the glass cloth package in the present disclosure is maintained is not particularly limited, but from the viewpoints of the time required for transporting the glass cloth and improving supply stability, etc., it is preferably 30 days or more and 5 years or less. The lower limit value of the storage period is preferably 30 days or more, more preferably 90 days or more, still more preferably 180 days or more, even more preferably 365 days or more, and particularly preferably 730 days or more. Also, from the viewpoint of reducing storage costs, etc., the upper limit value of the storage period of the glass cloth is preferably 5 years or less, more preferably 3 years or less. If the storage period is within the above range, the effects of using the glass cloth package of the present disclosure can be sufficiently obtained. The longer the storage period, the more remarkable the effect of suppressing the increase in the dielectric loss tangent can be obtained.

[0105] <Manufacturing method of glass cloth package> The glass cloth package of the present disclosure can be manufactured by packaging the glass cloth manufactured by the method described in the item of 《Method for Manufacturing Glass Cloth》 by the method described in the 〈Packaging Process〉 above, and these descriptions are incorporated into the method for manufacturing the glass cloth package.

Example

[0106] 《Measurement and Evaluation Method》 〈Measurement Method of Areal Density (Fabric Weight)〉 The areal density of the glass cloth was determined by cutting the glass cloth into a predetermined size and dividing its weight by the sample area. In this example or comparative example, the glass cloth was cut into a size of 10 cm 2 and the operation of measuring its weight was performed 10 times, and the average value was taken as the areal density of each glass cloth.

[0107] 〈Measurement Method of Equivalent Thickness〉 The glass cloth is a discontinuous planar body in which air exists between the glass fibers. Therefore, the equivalent thickness was calculated by dividing the areal density (mass of the cloth) of each glass cloth by the density of the glass. Specifically, the following formula: Equivalent thickness (μm) = Areal density (g / m 2 ) ÷ Density (g / cm 3 ) was used to calculate the equivalent thickness. The value of this equivalent thickness was used for measurement by the resonance method.

[0108] 〈Measurement Method of Dielectric Loss Tangent〉 In accordance with IEC 62562, the dielectric tangent of each glass cloth was determined. Specifically, samples of the glass cloth sampled to the size required for measurement with a split cylinder resonator were stored in a thermo-hygrostat oven at 23°C and 50% RH for 8 hours or more. Then, for the samples after storage, the dielectric properties at 10 GHz were measured using a split cylinder resonator (manufactured by EM Lab) and an impedance analyzer (manufactured by Agilent Technologies). The measurement was performed 5 times for each sample, and the average value was obtained. The above-converted thickness was used as the thickness of each sample. Note that IEC 62562 mainly stipulates the method for measuring the dielectric properties of fine ceramic materials used in microwave circuits in the microwave band.

[0109] 〈Method for Measuring the Loss on Ignition Value of Glass Cloth〉 In accordance with JIS R3420, the loss on ignition value of the glass cloth was determined.

[0110] 〈Method for Measuring Temperature and Dew Point〉 Temperature and dew point were measured using a handy type dew point meter DM70 manufactured by Vaisala Co., Ltd. Depending on the dew point to be measured, a DMP74A probe or a DMP74B probe and an MI70 indicator were used to measure the dew point under the atmospheric pressure of the storage environment. Specifically, the DMP74A probe was used when the dew point exceeded -30°C dp, and the DMP74B probe was used when the dew point was -30°C dp or lower. The average temperature and average dew point were obtained by averaging the temperature and dew point measured by the DM70 every 3 hours.

[0111] 〈Method for Measuring Pressure〉 The pressure gauge attached to the box was visually read to measure the pressure inside the box.

[0112] 〈Method for Measuring the Water Vapor Permeability of Packaging Materials and Core Tubes〉 Measurement Method A: In the case of plastic films, plastic sheets, and multi-layer materials containing plastics with a packaging material thickness of 2 mm or less In accordance with JIS K7130 and JIS K7129-1, the thickness and water vapor transmission rate of the packaging material were measured. The measurement was carried out 3 times for each sample, and the average value was taken as the thickness and water vapor transmission rate of the packaging material. For the test pieces, those without wrinkles, creases, or pinholes and with uniform thickness were used as visually inspected. · Equipment: Water Vapor Permeability Meter L80-5000 (manufactured by Lyssy, ISO-PE-Z91) · Thickness Gauge: ID-C1012C (manufactured by Mitutoyo, ISO-PE-Z78) · Temperature and Humidity: 40°C · 90% Rh · Measurement Area: Approximately 50 cm 2 · Reference Sample: PET with a thickness of 19 μm (25.5 g / (m 2 ×24 hr)) · Measurement Direction: Transmission from the surface where the glass cloth faces outside during packaging

[0113] Measurement Method B: When the packaging material is outside the scope of Measurement Method A and other than the core tube For packaging materials outside the scope of Measurement Method A, when the outside of the packaging material was set at a humidity of 90% Rh at a temperature of 40°C and the air inside was kept dry and sealed, the weight of the water vapor that penetrated into the inside of the packaging material was measured. The water vapor weight was per 24 hours of permeation time and per 1 m of the outer surface area of the packaging material 2It was calculated per hit. Specifically, dry air with a dew point of -30°C dp was enclosed inside the packaging material, 800 g of a desiccant of Class 1 A of JIS Z 0701 (Desiccant for Packaging) or of a quality equivalent to or higher than this was put in, the temperature and dew point were measured, and it was sealed. Here, when 800 g of desiccant does not fit, it is measured so that the weight of the enclosed desiccant can be known, and the desiccant is enclosed so as to have a capacity of half or more of the internal volume of the packaging material. Subsequently, the sealed packaging material was placed in a thermo-hygrostat at 40°C and 90% Rh, and the packaging material was stored in the thermo-hygrostat for an appropriate time of 48 hours or more. After a certain time (this time is referred to as the retention time in the thermo-hygrostat), the packaging material was taken out from the thermo-hygrostat, and immediately the temperature and dew point inside the packaging material and the weight of the desiccant after the test were measured. In addition, when the weight of the desiccant after the test exceeds 130% of the weight of the enclosed desiccant, the retention time in the thermo-hygrostat is shortened, or the amount of desiccant is increased, etc., and measurement is performed again. Also, from the temperature and dew point measured before the start of the test and after the end of the test, the absolute humidity (g / m 3 ) before the start of the test and after the end of the test was calculated. Specifically, the temperature and dew point were input into the VAISALA Humidity Calculator to obtain the absolute humidity. The measurement was carried out 3 times for each sample, and the water vapor transmission rate was calculated using the following formula, and the average value was taken as the water vapor transmission rate of the packaging material. Change in the amount of water vapor in the internal gas (g) = {Absolute humidity at the end of the test (g / m 3 ) - Absolute humidity at the start of the test (g / m 3 )} × Internal volume of the packaging material (m 3 ) Water vapor transmission rate (g / (m 2 × 24 hr)) = {Weight of the desiccant after the test (g) - Weight of the enclosed desiccant (g) + Change in the amount of water vapor in the internal gas (g)} / {External surface area of the packaging material (m 2 ) × {Retention time in the thermo-hygrostat (hr) / 24 (hr)}}

[0114] Measurement method C: For the core tube FIG. 2 is a schematic diagram for explaining a method of measuring water vapor permeability. As shown in FIG. 2, regarding the core tube, a film 13 whose water vapor permeability is known is wound around the outer surface of the core tube 11, and dry air with a dew point of -30°C dp is enclosed inside the space sandwiched between the film and the core tube. 800 g of a moisture absorbent 16 of Class 1 A of JIS Z 0701 (Desiccant for Packaging) or of a quality equivalent to or higher than this is placed, and a glass cloth package 10 is formed in which the joint 15 between the film and the core tube is sealed with tape. When the moisture absorbent does not contain 800 g, it is measured so that the weight of the enclosed moisture absorbent is known, and the moisture absorbent is enclosed so as to have a volume of at least half of the internal volume of the packaging material. Thereafter, the water vapor permeability of the packaging material was calculated in the same manner as <Method of Measuring Water Vapor Permeability of Packaging Material: Measuring Method B>. Thereafter, based on the water vapor permeability and the surface area of the film wound around the outer surface of the core tube, the water vapor permeability of the core tube was determined by the following formula. Water vapor permeability of packaging material (g / (m 2 ×24 hr)) = {Water vapor permeability of film (g / (m 2 ×24 hr)) × Surface area of film (m 2 ) + Water vapor permeability of core tube (g / (m 2 ×24 hr)) × Outer diameter side surface area of core tube (m 2 )} / {Surface area of film (m 2 ) + Outer diameter side surface area of core tube (m 2 )}

[0115] <Change rate of dielectric loss tangent (Df) of glass cloth> The change rate of the dielectric loss tangent (Df) of the glass cloth was determined by the following formula from the dielectric loss tangent (Df x ) after storage for X days with respect to the dielectric loss tangent (Df0) at the start of storage. Df change rate (%) = Df x / Df0 × 100

[0116] The smaller the rate of change (increase value) over time of the dielectric loss tangent of the glass cloth at 10 GHz over a long period, the greater the effect of maintaining the storage environment of the glass cloth. The rate of change of the glass cloth over time is evaluated by the above formula, and the rate of change of the dielectric loss tangent of the glass cloth 365 days after the start date of storing the glass cloth is preferably 180% or less, more preferably 160% or less, still more preferably 140% or less, even more preferably 120% or less, and particularly preferably 110% or less. Also, the rate of change of the dielectric loss tangent of the glass cloth 30 days after is preferably 120% or less, more preferably 115% or less, still more preferably 110% or less, and particularly preferably 105% or less. If the change in the dielectric loss tangent is within the above range (120% or less after 30 days and 180% or less after 365 days), it is considered that the effect of controlling the storage environment of the glass cloth has been obtained. The start date of storage is not particularly limited, but is based on the date when a person skilled in the art starts storing the glass cloth in a certain environment for a certain period. For example, after the surface treatment of the glass cloth is completed, the date when the glass cloth is packaged in a film and / or box-shaped packaging material is taken as the start date of storage, and the storage period is from the date of packaging the glass cloth until it is opened in the customer process.

[0117] 〈Rate of change of dew point〉 The rate of change of the dew point inside the package having a moisture absorbent was determined by the following formula. Rate of change of dew point = (dew point of the storage environment after 365 days of storage (°C dp) - initial dew point of the storage environment (°C dp)) / (average dew point of the external environment of the packaging material (°C dp) - dew point of the storage environment after 365 days of storage (°C dp)) However, when the average dew point of the external environment of the packaging material is equal to the dew point of the storage environment after 365 days of storage, it is considered non-conforming (NG).

[0118] 〈Method for measuring the surface area of the packaging material〉 The surface area of the packaging material was determined by measuring the shape from the state of the package after packaging. As shown in Fig. 1(1c), when the glass cloth is sealed from the external environment by a film and a core tube, the surface area of the packaging material was measured for the surface area of the film-shaped packaging material and the outer diameter side surface area of the core tube, respectively.

[0119] "Desiccant and Film" "Type of Desiccant" · Desiccant A: ABRIO (registered trademark) AW (type A silica gel) manufactured by Toyota Chemical Industry Co., Ltd. · Desiccant B: RP agent (calcined diatomaceous earth and calcium oxide) manufactured by Mitsubishi Gas Chemical Company, Inc. (MGC)

[0120] "Type of Film" "[Table 1]"

[0121] "Manufacture of Glass Cloth" "Manufacture of Q1035 (Raw Machine Cloth)" Using glass yarn with a SiO2 composition content of more than 99.9% by mass, an air jet loom was used to weave a cloth with a warp density of 66 threads / 25 mm and a weft density of 68 threads / 25 mm. Note that the weaving was performed so that the cloth width would be 1300 mm. As the warp, silica glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and a twist number of 1.0Z was used. Also, as the weft, silica glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and a twist number of 1.0Z was used.

[0122] "Manufacture of L1035 (Raw Machine Cloth) Cloth" Using glass yarn with a SiO2 composition content of 53% by mass and a B2O3 composition content of 23% by mass, an air jet loom was used to weave a cloth with a warp density of 66 threads / 25 mm and a weft density of 68 threads / 25 mm. Note that the weaving was performed so that the cloth width would be 1300 mm. As the warp, glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and a twist number of 1.0Z was used. Also, as the weft, glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and a twist number of 1.0Z was used.

[0123] "Examples and Comparative Examples" "Example A1" The obtained Q1035 green cloth was heated in a heating furnace at 600 °C for 60 seconds for degreasing (heating degreasing process). Subsequently, a treatment liquid was prepared by dispersing 0.15% by mass of 3-methacryloxypropyltrimethoxysilane (silane coupling agent A); Z6030 (manufactured by Dow Corning Toray Co., Ltd.) and 0.15% by mass of 5-hexenyltrimethoxysilane (silane coupling agent B); Z6161 (manufactured by Dow Corning Toray Co., Ltd.) in pure water adjusted to pH = 3 with acetic acid. The cloth was immersed in the treatment liquid at a line tension of 200 N and a line speed of 30 m / min (surface treatment agent coating process). After squeezing the liquid with an NBR rubber roll at a pressure of 0.3 MPa, it was heated and dried at 130 °C for 60 seconds to fix the silane coupling agent (fixing process). The dried cloth was opened under high pressure at a pressure of 2.0 kg / cm 2 and then dried at 130 °C for 1 minute (drying process) and wound up to obtain a roll-shaped glass cloth. This glass cloth was placed in a storage room maintained at a temperature of 23 °C and a dew point of -30 °C dp by circulating dry air at -30 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0124] <Example A2> The roll-shaped glass cloth obtained in Example A1 was packaged in a bag of Film A (thickness 99 μm, water vapor permeability 0.1 g / (m 2 ×24 h)) in an environment at a temperature of 23 °C, and a moisture absorbent A (800 g) was enclosed inside. Further, dry air with a dew point of -20 °C dp was enclosed inside to set the dew point to -20 °C dp, and the opening was heat-sealed to obtain a packaged glass cloth. Thereafter, the packaged glass cloth was moved to an external environment at a temperature of 30 °C and a dew point of 24 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0125] <Example A3> The obtained Q1035 green cloth was heated at 1000 °C for 60 seconds for degreasing, and then a roll-shaped glass cloth was obtained by the same processing as in Example A1 except for degreasing. This glass cloth was placed in a box-shaped packaging material (water vapor permeability 0.0 g / (m 2It was placed in (×24 hr). Subsequently, desiccant A (800 g) was enclosed inside the package, which was then sealed and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0126] 〈Example A4〉 The obtained Q1035 viable cloth was used as a heat degreasing step by heating at 370 °C for 72 hours using a batch-type heating furnace. A roll-shaped glass cloth was obtained in the same manner as in Example A1, except that a treatment liquid in which 3-methacryloxypropyltrimethoxysilane (silane coupling agent A); Z6030 (manufactured by Dow Corning Toray Co., Ltd.) was dispersed at 0.30% by mass was prepared and used. This glass cloth was packaged in a bag of Film A (thickness 99 μm, water vapor permeability 0.1 g / (m 2 ×24 hr)) and desiccant B (800 g) was enclosed inside. Furthermore, the packaged glass cloth was obtained by thermocompression bonding and sealing the opening. Thereafter, the packaged glass cloth was transferred to an external environment at a temperature of 30 °C and a dew point of 24 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0127] 〈Example A5〉 The roll-shaped glass cloth obtained in Example A1 was placed in a storage room maintained at a temperature of 25 °C and a dew point of 2 °C dp using a dehumidifier and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0128] 〈Example A6〉 The roll-shaped glass cloth obtained in Example A1 was placed in a storage room maintained at a temperature of 25 °C and a dew point of 8 °C dp using a dehumidifier and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0129] 〈Example A7〉 The roll-shaped glass cloth obtained in Example A1 was placed in a box-shaped packaging material (water vapor permeability 0.0 g / (m 2 ×24 hr)) at an environment of a temperature of 30 °C and a dew point of 24 °C dp, and the inside was evacuated to 10 3After depressurizing to Pa, it was sealed and stored. At this time (10 3 The dew point inside the box-shaped packaging material at Pa) was -32°C dp. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0130] <Example A8> The roll-shaped glass cloth obtained in Example A1 was placed in an environment with a temperature of 23°C and a dew point of 12°C dp, and packaged in a bag of Film B (thickness 116 μm, water vapor permeability 0.2 g / (m 2 ×24 hr)), and a moisture absorbent A (800 g) was enclosed inside. Further, dry air with a dew point of -20°C dp was enclosed inside to make the dew point -20°C dp, and the opening was heat-sealed to obtain a packaged glass cloth. Then, the packaged glass cloth was moved to an external environment with a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0131] <Example A9> The roll-shaped glass cloth obtained in Example A1 was placed in an environment with a temperature of 23°C and a dew point of 12°C dp, and packaged in a bag of Film C (thickness 78 μm, moisture permeability 6.6 g / (m 2 ×24 hr)), and a moisture absorbent A (8000 g) was enclosed inside. Further, the opening was heat-sealed to obtain a packaged glass cloth. Then, the packaged glass cloth was moved to an external environment with a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0132] <Example A10> The roll-shaped glass cloth obtained in Example A1 was placed in a storage room maintained at a temperature of 45°C and a dew point of -2°C dp by circulating dry air with a dew point of -2°C dp, and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0133] <Example A11> The obtained Q1035 green glass cloth was heated in a heating furnace at 600 °C for 60 seconds for degreasing (heating degreasing process), and then wound up to obtain a roll-shaped glass cloth. This glass cloth was placed in a storage room maintained at a temperature of 23 °C and a dew point of -30 °C dp by circulating dry air at -30 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0134] <Comparative Example A1> The roll-shaped glass cloth obtained in Example A1 was placed in a storage room maintained at a temperature of 30 °C and a dew point of 24 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0135] <Reference Example A> A roll-shaped glass cloth was obtained in the same manner as in Example A1, except that the obtained L1035 green glass cloth was heated at 370 °C for 72 hours using a batch-type heating furnace as a heating degreasing process. This glass cloth was placed in a storage room maintained at a temperature of 30 °C and a dew point of 24 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0136] <Comparative Example A2> The roll-shaped glass cloth obtained in Example A3 was placed in a storage room maintained at a temperature of 30 °C and a dew point of 24 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0137] <Comparative Example A3> The roll-shaped glass cloth obtained in Example A4 was placed in a storage room maintained at a temperature of 30 °C and a dew point of 24 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0138] <Comparative Example A4> The roll-shaped glass cloth obtained in Example A1 was placed in a storage room maintained at a temperature of 40 °C and a dew point of 38 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0139] <Comparative Example A5> The roll-shaped glass cloth obtained in Example A1 was wrapped in a bag of Film D (thickness 45 μm, water vapor permeability 11 g / (m 2 ×24 hr)) under an environment of temperature 23°C and dew point 12°C dp, and a moisture absorbent A (8000 g) was enclosed inside. Furthermore, the glass cloth thus packaged was obtained by thermocompression bonding and sealing the opening. Then, the packaged glass cloth was moved to an external environment of temperature 30°C and dew point 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0140] 〈Comparative Example A6〉 The roll-shaped glass cloth obtained in Example A11 was placed in a storage room maintained at a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0141] The manufacturing conditions and evaluation results regarding Examples A1 to A11, Comparative Examples A1 to A6, and Reference Example A are shown in the table below.

[0142]

Table 2

[0143]

Table 3

[0144] In Example A1, the dielectric loss tangent of the glass cloth after long-term storage (after 30 days and 365 days) did not change, whereas in Comparative Example A1, the dielectric loss tangent of the glass cloth increased significantly. On the other hand, in Reference Example A where the dielectric loss tangent of the glass cloth was higher than 0.00200, no increase in the dielectric loss tangent was observed even in the same storage environment as Comparative Example A1. In Comparative Example A5, since the water vapor permeability of the bag for packaging the glass cloth was high, the amount of water inflow increased, and it was difficult to sufficiently lower the internal dew point even when using a moisture absorbent.

[0145] 《Moisture Absorbent and Packaging Material》 〈Type of Moisture Absorbent〉 · Desiccant A: ABRIO (registered trademark) AW (type A silica gel) manufactured by Toyota Chemical Industries Co., Ltd. · Desiccant B: RP agent (calcined diatomaceous earth and calcium oxide) manufactured by Mitsubishi Gas Chemical Company, Inc. (MGC)

[0146] 〈Type of packaging material〉

Table 4

[0147] 《Manufacture of glass cloth》 〈Manufacture of Q1035 (biological cloth)〉 Using glass yarn with a SiO2 composition content of more than 99.9% by mass, an air jet loom was used to weave a cloth with a warp density of 66 threads / 25 mm and a weft density of 68 threads / 25 mm. The cloth was woven so that the cloth width was 1300 mm. As the warp, silica glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and a twist number of 1.0Z was used. Also, as the weft, silica glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and a twist number of 1.0Z was used.

[0148] 〈Manufacture of L1035 (biological cloth) cloth〉 Using glass yarn with a SiO2 composition content of 53% by mass and a B2O3 composition content of 23% by mass, an air jet loom was used to weave a cloth with a warp density of 66 threads / 25 mm and a weft density of 68 threads / 25 mm. The cloth was woven so that the cloth width was 1300 mm. As the warp, glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and a twist number of 1.0Z was used. Also, as the weft, glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and a twist number of 1.0Z was used.

[0149] 《Examples and Comparative Examples》 〈Example B1〉 The obtained green Q1035 cloth was heated in a heating furnace at 600 °C for 60 seconds for oil removal (heating and oil removal process). Subsequently, in pure water adjusted to pH = 3 with acetic acid, 3-methacryloxypropyltrimethoxysilane (silane coupling agent A); Z6030 (manufactured by Dow Corning Toray Co., Ltd.) was 0.15% by mass, and 5-hexenyltrimethoxysilane (silane coupling agent B); Z6161 (manufactured by Dow Corning Toray Co., Ltd.) was 0.15% by mass to prepare a treatment liquid. The cloth was immersed in the treatment liquid at a line tension of 200 N and a line speed of 30 m / min (surface treatment agent coating process). After squeezing the liquid with an NBR rubber roll at a pressure of 0.3 MPa, it was heated and dried at 130 °C for 60 seconds to fix the silane coupling agent (fixing process). The dried cloth was spray-opened at a pressure of 2.0 kg / cm 2 After high-pressure fiber opening, it was dried at 130 °C for 1 minute (drying process), and a roll-shaped glass cloth was obtained by winding it around a core tube having a hollow part.

[0150] This glass cloth was packaged with Packaging Material A (aluminum laminate film, thickness 99 μm, water vapor permeability 0.1 g / (m 2 ×24 hr)) in an environment at a temperature of 23 °C, and a moisture absorbent A (800 g) was enclosed inside. Further, dry air with a dew point of -20 °C dp was enclosed inside to set the dew point to -20 °C dp, and the opening was heat-sealed to obtain a glass cloth package. Then, the glass cloth package was transferred to an external environment at a temperature of 30 °C and a dew point of 24 °C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0151] 〈Example B2〉 The obtained green Q1035 cloth was heated at 1000 °C for 60 seconds for oil removal, and a roll-shaped glass cloth was obtained by the same processing as in Example B1 except for this. This glass cloth was packaged with Packaging Material F (stainless steel box, water vapor permeability 0.0 g / (m 2It was placed in (×24 hours). Subsequently, desiccant A (800 g) was enclosed inside the packaging material and sealed to form a glass cloth package. Thereafter, the glass cloth package was moved to an external environment with a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0152] 〈Example B3〉 The obtained Q1035 viable cloth was heated at 370°C for 72 hours using a batch-type heating furnace as a heat-deoiling process, and a treatment liquid in which 3-methacryloxypropyltrimethoxysilane (silane coupling agent A); Z6030 (manufactured by Dow Corning Toray Co., Ltd.) was dispersed at 0.30% by mass was prepared and used. A roll-shaped glass cloth was obtained in the same manner as in Example B1 except for this point. This glass cloth was placed in an environment with a temperature of 23°C and a dew point of 12°C dp and packaged with Packaging Material A (aluminum laminate film, thickness 99 μm, water vapor permeability 0.1 g / (m 2 ×24 hours)) and desiccant B (800 g) was enclosed inside. Furthermore, the opening was heat-sealed to obtain a glass cloth package. Thereafter, the glass cloth package was moved to an external environment with a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0153] 〈Example B4〉 The roll-shaped glass cloth obtained in Example B1 was packaged with Packaging Material B (ceramic vapor deposition film, thickness 116 μm, water vapor permeability 0.2 g / (m 2 ×24 hours)) in an environment with a temperature of 23°C, and desiccant A (800 g) was enclosed inside. Furthermore, dry air with a dew point of -20°C dp was enclosed inside to set the dew point to -20°C dp, and the opening was heat-sealed to obtain a glass cloth package. Thereafter, the glass cloth package was moved to an external environment with a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0154] 〈Example B5〉 The roll-shaped glass cloth obtained in Example B1 was placed in an environment of a temperature of 23°C and a dew point of 12°C dp, and was packaged with Packaging Material C (ceramic vapor-deposited film, thickness 115 μm, water vapor permeability 1.5 g / (m 2 ×24 hr)), and a moisture absorbent A (8000 g) was enclosed inside. The opening was heat-sealed to obtain a glass cloth package. Thereafter, the glass cloth package was transferred to an external environment of a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0155] 〈Example B6〉 The roll-shaped glass cloth obtained in Example B1 was placed in an environment of a temperature of 23°C and a dew point of 12°C dp, and was packaged with Packaging Material D (ceramic vapor-deposited film, thickness 78 μm, water vapor permeability 6.6 g / (m 2 ×24 hr)), and a moisture absorbent A (8000 g) was enclosed inside. Further, the opening was heat-sealed to obtain a glass cloth package. Thereafter, the glass cloth package was transferred to an external environment of a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0156] 〈Example B7〉 The roll-shaped glass cloth obtained in Example B1 was placed in an environment of a temperature of 30°C and a dew point of 24°C dp, and was put into Packaging Material F (stainless steel box, water vapor permeability 0.0 g / (m 2 ×24 hr)). After evacuating the inside to 10 3 Pa using a vacuum pump, it was sealed to obtain a glass cloth package. At this time, the dew point inside the glass cloth package at (10 3 Pa) was -32°C dp. Thereafter, the glass cloth package was transferred to an external environment of a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0157] 〈Example B8〉 The obtained Q1035 green glass cloth was heated in a heating furnace at 600°C for 60 seconds to remove oil (heating and oil removal process), and then wound around a core tube having a hollow part to obtain a roll-shaped glass cloth. This glass cloth was packaged with Packaging Material A (aluminum laminate film, thickness 99 μm, water vapor permeability 0.1 g / (m 2 ×24 hr)) in an environment at a temperature of 23°C, and a moisture absorbent A (800 g) was enclosed inside. Further, dry air with a dew point of -20°C dp was enclosed inside to set the dew point to -20°C dp, and the opening was heat-sealed to obtain a glass cloth package. Thereafter, the glass cloth package was transferred to an external environment at a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0158] 〈Comparative Example B1〉 The roll-shaped glass cloth obtained in Example B1 was packaged with Packaging Material E (polyethylene film, thickness 45 μm, moisture permeability 11 g / (m 2 ×24 hr)) in an environment at a temperature of 23°C and a dew point of 12°C dp, and a moisture absorbent A (8000 g) was enclosed inside. Further, the opening was heat-sealed to obtain a glass cloth package. Thereafter, the glass cloth package was transferred to an external environment at a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0159] 〈Reference Example B〉 A roll-shaped glass cloth was obtained in the same manner as in Example B1, except that the obtained L1035 green glass cloth was heated at 370°C for 72 hours using a batch-type heating furnace as a heating and oil removal process. This glass cloth was packaged with Packaging Material E (polyethylene film, thickness 45 μm, moisture permeability 11 g / (m 2 ×24 hr)) in an environment at a temperature of 23°C and a dew point of 12°C dp, and a moisture absorbent A (8000 g) was enclosed inside. Further, the opening was heat-sealed to obtain a glass cloth package. Thereafter, the glass cloth package was transferred to an external environment at a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0160] <Comparative Example B2> The roll-shaped glass cloth obtained in Example B2 was placed in Packaging Material G (corrugated box, water vapor permeability 50 g / (m 2 ×24 hr)) in an environment of 23°C temperature and 12°C dp dew point. Subsequently, a moisture absorbent A (8000 g) was enclosed inside the package, and it was sealed to form a glass cloth package. Then, the glass cloth package was moved to an external environment of 30°C temperature and 24°C dp dew point and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0161] <Comparative Example B3> The roll-shaped glass cloth obtained in Example B3 was placed in Packaging Material G (corrugated box, water vapor permeability 50 g / (m 2 ×24 hr)) in an environment of 23°C temperature and 12°C dp dew point, and it was sealed to form a glass cloth package. Then, the glass cloth package was moved to an external environment of 30°C temperature and 24°C dp dew point and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0162] <Comparative Example B4> The roll-shaped glass cloth obtained in Example B8 was packaged with Packaging Material E (polyethylene film, thickness 45 μm, water vapor transmission rate 11 g / (m 2 ×24 hr)) in an environment of 23°C temperature and 12°C dp dew point, and the opening was heat-sealed to obtain a glass cloth package. Then, the glass cloth package was moved to an external environment of 30°C temperature and 24°C dp dew point and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0163] The manufacturing conditions and evaluation results regarding Examples B1 to B8, Comparative Examples B1 to B4, and Reference Example B are shown in the following table.

[0164] [Table 5]

[0165] [Table 6]

[0166] In Example B1, the dielectric loss tangent of the glass cloth did not change after long-term storage (after 30 days and 365 days), while in Comparative Example B1, the dielectric loss tangent of the glass cloth increased significantly. In Comparative Example B1, since the water vapor permeability of the bag for packaging the glass cloth was high, the amount of water flowing in increased, and it was difficult to sufficiently lower the internal dew point even when a desiccant was used. On the other hand, in Reference Example B where the dielectric loss tangent of the glass cloth was higher than 0.00200, no increase in the dielectric loss tangent was observed even in the same storage environment as Comparative Example B1.

[0167] 〈Type of core tube〉

Table 7

[0168] 〈Example B9〉 The roll-shaped glass cloth obtained in Example B1 was packaged at a temperature of 23°C in Packaging Material A (aluminum laminate film, thickness 99 μm, water vapor permeability 0.1 g / (m 2 ×24 hr)) wider than the width of the roll, and Desiccant A (800 g) was enclosed inside. With dry air at a dew point of -20°C dp enclosed inside Packaging Material A to make the dew point -20°C dp, the opening was heat-sealed and sealed. The excess packaging material on one side was pushed into the hollow part of the core tube to obtain a glass cloth package having a recess extending from one end of the core tube to the inside of the hollow part. The surface area of Packaging Material A was 3.5 m 2 and the volume occupied by the space inside the package in the volume of the hollow part of the core tube was 20%. Thereafter, the glass cloth package was moved to an external environment at a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0169] 〈Example B10〉 The roll-shaped glass cloth obtained in Example B1 was packaged at a temperature of 23°C in Packaging Material A (aluminum laminate film, thickness 99 μm, water vapor permeability 0.1 g / (m 2It was packaged in a way that it could withstand 24 hours and a desiccant A (800 g) was enclosed inside. Inside the core tube around which the roll-shaped glass cloth was wound, a tubular packaging material A was inserted along the inner wall thereof. With dry air having a dew point of -20°C dp enclosed inside the packaging material A covering the outer surface of the roll to set the dew point to -20°C dp, the packaging material A covering the outer surface of the roll and the tubular packaging material A penetrating the inner diameter portion of the core tube were thermocompression bonded to seal the opening, and an annular glass cloth package was obtained in which the hollow portion was penetrated by the external environment. At this time, the surface area of the packaging material A was 3.0 m 2 The volume occupied by the space inside the package out of the volume of the hollow portion of the core tube was 5%. Thereafter, the glass cloth package was moved to an external environment with a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0170] <Example B11> The obtained glass cloth was wound around an FRP core tube H with a water vapor permeability of 0.1 g / (m 2 ×24 hr) to obtain a roll-shaped glass cloth in the same manner as in Example B1 except for this. This roll-shaped glass cloth was packaged with a packaging material A (aluminum laminate film, thickness 99 μm, water vapor permeability 0.1 g / (m 2 ×24 hr)) in an environment with a temperature of 23°C, and a desiccant A (800 g) was enclosed inside. With dry air having a dew point of -20°C dp enclosed inside the packaging material A to set the dew point to -20°C dp, the film at the opening was attached to the exposed outer surface of the core tube with a moisture-proof airtight tape and sealed to obtain a glass cloth package. At this time, the surface area of the packaging material A was 2.0 m 2 The outer diameter side surface area of the core tube was 1.0 m 2 The volume occupied by the space inside the package out of the volume of the hollow portion of the core tube was 0%. Thereafter, the glass cloth package was moved to an external environment with a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0171] <Example B12> The obtained glass cloth had a water vapor permeability of 1.0 g / (m 2A roll-shaped glass cloth was obtained in the same manner as in Example B1, except that it was wound around an FRP core tube I for 24 hours. This roll-shaped glass cloth was placed in an environment at a temperature of 23°C and packaged with Packaging Material A (aluminum laminate film, thickness 99 μm, water vapor transmission rate 0.1 g / (m 2 ×24 hr)), and a moisture absorbent A (1200 g) was enclosed inside. With dry air having a dew point of -20°C dp enclosed inside Packaging Material A to set the dew point to -20°C dp, the film at the opening was attached to the exposed outer surface of the core tube with a moisture-proof and airtight tape and sealed to obtain a glass cloth package. At this time, the surface area of Packaging Material A was 2.0 m 2 and the outer diameter side surface area of the core tube was 1.0 m 2 . The volume occupied by the space inside the package out of the volume of the hollow part of the core tube was 0%. Thereafter, the glass cloth package was moved to an external environment at a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0172] 〈Comparative Example B5〉 A roll-shaped glass cloth was obtained in the same manner as in Example B1, except that the obtained glass cloth was wound around a paper core tube J with a water vapor transmission rate of 9.6 g / (m 2 ×24 hr). This roll-shaped glass cloth was packaged with Packaging Material E (polyethylene film, thickness 45 μm, moisture permeability 11 g / (m 2 ×24 hr)) in an environment at a temperature of 23°C and a dew point of 12°C dp, and a moisture absorbent A (8000 g) was enclosed inside. The film at the opening was attached to the core tube with a moisture-proof and airtight tape and sealed to obtain a glass cloth package. At this time, the surface area of Packaging Material E was 1.8 m 2 and the outer diameter side surface area of the core tube was 0.8 m 2 . The volume occupied by the space inside the package out of the volume of the hollow part of the core tube was 0%. Thereafter, the glass cloth package was moved to an external environment at a temperature of 30°C and a dew point of 24°C dp and stored. After 30 days and 365 days, the glass cloth was taken out and evaluated.

[0173] The manufacturing conditions and evaluation results for Examples B9 to B12 and Comparative Example B5 are shown in the following table.

[0174]

Table 8

[0175] In Examples B1 to B12, the dielectric tangent of the glass cloth did not change after long-term storage (after 30 days and 365 days), whereas in Comparative Example B5, the dielectric tangent of the glass cloth increased significantly.

Explanation of Signs

[0176] 10 Glass cloth package 11 Core tube 12 Glass cloth 13 Film 13a Outer film 13b Inner film 14 Recess 15 Joint 16 Desiccant

Claims

1. A method for storing a glass cloth, comprising: The glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft yarns, the silicon (Si) content in the glass yarns is 95.0% to 100% by mass in terms of silicon dioxide (SiO₂), and the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less; The method includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 10 °C dp or less and the average temperature is 100 °C or less; The glass cloth has a surface treatment agent containing a silane coupling agent on its surface; The method further includes a step of surface-treating the glass cloth with a surface treatment agent containing a silane coupling agent before the storage, and a step of opening the surface-treated glass cloth. A method for storing a glass cloth.

2. A method for storing a glass cloth, comprising: The glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft yarns, the silicon (Si) content in the glass yarns is 95.0% to 100% by mass in terms of silicon dioxide (SiO₂), and the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less; The method includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 10 °C dp or less and the average temperature is 100 °C or less for 90 days or more; The glass cloth is stored as a package wrapped with a film-like packaging material, and the thickness of the film-like packaging material is 50 μm or more; A method for storing a glass cloth, wherein the change rate of the dielectric loss tangent when the glass cloth is stored for 365 days is 140% or less.

3. A method for storing a glass cloth, comprising: The glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft yarns, the silicon (Si) content in the glass yarns is 95.0% to 100% by mass in terms of silicon dioxide (SiO₂), and the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less; The method includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 10 °C dp or less and the average temperature is 100 °C or less for 90 days or more; The glass cloth is stored as a package wrapped with a film-like packaging material in a state of a roll wound around a hollow columnar core tube, and the film-like packaging material has a recess extending into the hollow portion from one end or both ends of the core tube, or is an annular shape penetrating the hollow portion of the core tube, A method for storing a glass cloth, wherein the change rate of the dielectric loss tangent when the glass cloth is stored for 365 days is 140% or less.

4. A method for storing a glass cloth, The glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft, the silicon (Si) content in the glass yarn is 95.0% by mass to 100% by mass in terms of silicon dioxide (SiO₂), and the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less, The method includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 10 °C dp or less and the average temperature is 100 °C or less, The glass cloth is stored as a package wrapped with a box and / or a film-like packaging material, The package has a moisture absorbent, The enclosed amount of the moisture absorbent satisfies the following formula (2): WVTR [g / (m ２ × 24 hr)] × package surface area [m ２ / desiccant encapsulation amount [g] ≤ 0.0030... (2) (In formula (2), WVTR is the water vapor transmission rate of the packaging material at a measurement temperature of 40 °C and a measurement humidity of 90% Rh.) A method for storing a glass cloth.

5. A method for storing a glass cloth, The glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft, the silicon (Si) content in the glass yarn is 95.0% by mass to 100% by mass in terms of silicon dioxide (SiO₂), and the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less, The method includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 10 °C dp or less and the average temperature is 100 °C or less for 90 days or more, The atmosphere is depressurized to less than atmospheric pressure, A method for storing a glass cloth, wherein the change rate of the dielectric loss tangent when the glass cloth is stored for 365 days is 140% or less.

6. A method for storing a glass cloth, The glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft, the silicon (Si) content in the glass yarn is 95.0% to 100% by mass in terms of silicon dioxide (SiO₂), and the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less. The method includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 10 °C dp or less and the average temperature is 100 °C or less. The method further includes a step of heating the glass cloth at a temperature of 600 °C or higher while conveying it in a Roll-to-Roll manner before the storage. Method for storing a glass cloth.

7. A method for storing a glass cloth, comprising: The glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft, the silicon (Si) content in the glass yarn is 95.0% to 100% by mass in terms of silicon dioxide (SiO₂), and the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less. The method includes storing the glass cloth in an atmosphere where the average dew point under the atmospheric pressure of the storage environment is 10 °C dp or less and the average temperature is 100 °C or less. The method further includes a step of heating the glass cloth at a temperature of 800 °C or higher and 1500 °C or lower before the storage. Method for storing a glass cloth.

8. The method according to any one of claims 2 to 7, wherein the glass cloth has a surface treatment agent containing a silane coupling agent on its surface.

9. The surface treatment agent is represented by the following formula (1): X(R) ３－ｎ SiY ｎ ...(1) (In formula (1), X is an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is each independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group) The method according to claim 8, comprising a silane coupling agent represented by the formula.

10. The method according to claim 9, wherein the surface treatment agent contains two or more kinds of silane coupling agents having different Xs in the formula (1).

11. The method according to claim 8, wherein the surface treatment agent contains two or more kinds of silane coupling agents having different molecular weights.

12. The method according to claim 8 further includes, before the storing, a step of surface-treating the glass cloth with a surface treatment agent containing a silane coupling agent, and a step of fibrillating the surface-treated glass cloth.

13. The method according to any one of claims 1 to 7, wherein the dielectric tangent of the glass cloth at 10 GHz is 0.00051 or more and 0.00200 or less.

14. The method according to any one of claims 1 to 7, wherein the driving-in density of the warp and / or weft of the glass cloth is in the range of 66 to 120 threads / inch (= 66 to 120 threads / 25 mm).

15. The method according to any one of claims 1 to 5 further includes, before the storing, a step of heating the glass cloth at a temperature of 600 °C or more while conveying the glass cloth in a Roll-to-Roll manner.

16. The method according to any one of claims 1 and 5 to 7, wherein the glass cloth is stored as a package wrapped with a box and / or a film-like packaging material.

17. The method according to any one of claims 1 and 3 to 7, wherein the glass cloth is stored as a package wrapped with a film-like packaging material, and the thickness of the film-like packaging material is 50 μm or more.

18. The method according to any one of claims 1 to 7, wherein the glass cloth is stored as a package wrapped with a film-like packaging material, and the film-like packaging material is an aluminum laminated film.

19. The method according to any one of claims 1, 2 and 4 to 7, wherein the glass cloth is stored as a package wrapped with a film-like packaging material in a state of a roll wound around a hollow columnar core tube, and the film-like packaging material has a recess extending into the hollow portion from one end or both ends of the core tube, or is an annular shape penetrating the hollow portion of the core tube.

20. The method according to claim 3, wherein the ratio of the volume occupied by the space inside the film-like packaging material in the hollow volume of the core tube is 50% or less of the hollow volume of the core tube.

21. The method according to claim 3, wherein the film-like packaging material is an annular shape penetrating the hollow portion of the core tube.

22. The method according to claim 3, wherein the package is configured such that the glass cloth is sealed from the external environment by the film-like packaging material and the core tube.

23. The water vapor transmission rate measured under the conditions of 40 °C and 90% Rh of the core tube is 8 g / (m ２ ×24 hr) or less, the method according to claim 3.

24. The packaging material has a water vapor permeability of 8 g / (m ２ ×24 hr) or less at a measurement temperature of 40°C and a measurement humidity of 90% Rh. The method according to any one of claims 2 to 4.

25. The method according to any one of claims 2 to 4, wherein the package is configured to dehumidify so as to maintain the average dew point inside the package at 10°C dp or less.

26. The method according to any one of claims 1 to 7, including storing at an average dew point of -21°C dp or less under the atmospheric pressure of the storage environment.

27. The method according to any one of claims 2 to 4, wherein the package contains a moisture absorbent.

28. The enclosed amount of the moisture absorbent satisfies the following formula (2): WVTR [g / (m ２ × 24 hr)] × package surface area [m ２ / desiccant encapsulation amount [g] ≤ 0.0030... (2) (In formula (2), WVTR is the water vapor transmission rate of the packaging material at a measurement temperature of 40°C and a measurement humidity of 90% Rh.) The method according to claim 27.

29. The method according to claim 27, wherein the moisture absorbent is at least one selected from the group consisting of silica gel, calcium oxide, calcium chloride, calcined diatomaceous earth, synthetic zeolite, clay-based desiccant, phosphorus pentoxide, magnesium sulfate, copper sulfate, magnesium chloride, cobalt chloride, granular soda lime, and magnesium perchlorate.

30. The method according to claim 28, wherein the moisture absorbent is a sheet-shaped moisture absorbent.

31. The method according to any one of claims 1 to 7, wherein the atmosphere is dry air with an average dew point of 10°C dp or less, or a gas containing at least one selected from the group consisting of nitrogen, argon, and oxygen with an average dew point of 10°C dp or less.

32. The method according to any one of claims 1 to 4, 6, and 7, wherein the atmosphere is depressurized to less than atmospheric pressure.

33. The method according to any one of claims 1 to 7, wherein the glass cloth is stored in a storage room with controlled dew point and temperature.

34. The basis weight (mass of the glass cloth) of the glass cloth is in the range of 8 to 25 g / m ２ The method according to any one of claims 1 to 7, wherein the method is as described above.

35. A glass cloth package including a packaging material and a glass cloth stored inside the packaging material, wherein the glass cloth is composed of glass yarns containing a plurality of filaments as warp and weft, the silicon (Si) content in the glass yarn is 95.0% by mass to 100% by mass in terms of silicon dioxide (SiO₂), the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less, the packaging material is sealed, The water vapor permeability of the packaging material measured under the conditions of 40°C and 90% Rh is 8 g / (m ２ ×24 hr) or less, the packaging material is a film, the thickness of the film is 50 μm or more, the dew point inside the packaging material is 10°C dp or less, A glass cloth package, wherein when the glass cloth is sealed for 365 days in an atmosphere with an average temperature of 100°C or less, the change rate of the dielectric loss tangent is 140% or less.

36. A glass cloth package including a packaging material and a glass cloth housed inside the packaging material, wherein the glass cloth is composed of glass yarns including a plurality of filaments as warp and weft, the silicon (Si) content in the glass yarn is 95.0% by mass to 100% by mass in terms of silicon dioxide (SiO₂), the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less, the packaging material is sealed, The water vapor transmission rate of the packaging material measured under the conditions of 40°C and 90% Rh is 8 g / (m ２ ×24 hr) or less, the packaging material is a film, the glass cloth is packaged in the film in a state of a roll wound around a hollow columnar core tube, and the film has a recess extending into the hollow portion from one end or both ends of the core tube, or is an annular shape penetrating the hollow portion of the core tube, the dew point inside the packaging material is 10 °C dp or less, a glass cloth package, wherein when the glass cloth is sealed for 365 days in an atmosphere with an average temperature of 100 °C or less, the change rate of the dielectric loss tangent is 140% or less.

37. A glass cloth package including a packaging material and a glass cloth housed inside the packaging material, wherein the glass cloth is composed of glass yarns including a plurality of filaments as warp and weft, the silicon (Si) content in the glass yarn is 95.0% by mass to 100% by mass in terms of silicon dioxide (SiO₂), the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less, the packaging material is sealed, a moisture absorbent is enclosed inside the packaging material, The water vapor permeability of the packaging material measured under the conditions of 40 °C and 90% Rh is 8 g / (m ２ ×24 hr) or less, the enclosed amount of the moisture absorbent satisfies the following formula (2): WVTR [g / (m ２ × 24 hr)] × package surface area [m ２ / desiccant encapsulation amount [g] ≤ 0.0030... (2) (In formula (2), WVTR is the water vapor transmission rate of the packaging material at a measurement temperature of 40 °C and a measurement humidity of 90% Rh.) the dew point inside the packaging material is 10 °C dp or less, a glass cloth package.

38. A glass cloth package including a packaging material and a glass cloth housed inside the packaging material, wherein the glass cloth is composed of glass yarns including a plurality of filaments as warp and weft, the silicon (Si) content in the glass yarn is 95.0% by mass to 100% by mass in terms of silicon dioxide (SiO₂), the dielectric loss tangent of the glass cloth at 10 GHz is 0.00200 or less, the packaging material is sealed, the pressure inside the packaging material is less than atmospheric pressure, the dew point inside the packaging material is 10 °C dp or less, A glass cloth package in which the rate of change of the dielectric loss tangent is 140% or less when the glass cloth is sealed for 365 days in an atmosphere with an average temperature of 100°C or lower.

39. The glass cloth package according to claim 37 or 38, wherein the packaging material is a box and / or a film.

40. The glass cloth package according to claim 39, wherein the packaging material is a film and the thickness of the film is 50 μm or more.

41. The glass cloth package according to claim 39, wherein the packaging material is a film and the film is an aluminum laminated film.

42. The glass cloth is packaged in a film in a state of a roll wound around a hollow columnar core tube, and the film has a recess extending into the hollow portion from one end or both ends of the core tube, or is an annular shape penetrating the hollow portion of the core tube. The glass cloth package according to claim 39.

43. The glass cloth package according to claim 42, wherein the ratio of the space inside the film to the volume of the hollow portion of the core tube is 50% or less of the volume of the hollow portion of the core tube.

44. The glass cloth package according to claim 42, wherein the film is an annular shape penetrating the hollow portion of the core tube.

45. The glass cloth package according to claim 42, wherein the package is configured such that the glass cloth is sealed from the external environment by the film and the core tube.

46. The water vapor permeability of the core tube measured under the conditions of 40 °C and 90% Rh is 8 g / (m ２ ×24 hr) or less, the glass cloth package according to claim 42.

47. The glass cloth package according to any one of claims 35 to 38, wherein the dew point inside the packaging material is -21°C dp or lower.

48. The glass cloth package according to any one of claims 35 to 38, wherein the glass cloth is in a roll state.

49. The glass cloth package according to any one of claims 35, 36 and 38, wherein a moisture absorbent is enclosed inside the packaging material.

50. The enclosed amount of the moisture absorbent satisfies the following formula (2): WVTR [g / (m ２ × 24 hr)] × package surface area [m ２ / desiccant encapsulation amount [g] ≤ 0.0030... (2) (In formula (2), WVTR is the water vapor transmission rate of the packaging material at a measurement temperature of 40°C and a measurement humidity of 90% Rh.) The glass cloth package according to claim 49.

51. The glass cloth package according to claim 49, wherein the moisture absorbent is at least one selected from the group consisting of silica gel, calcium oxide, calcium chloride, calcined diatomaceous earth, synthetic zeolite, clay-based desiccant, phosphorus pentoxide, magnesium sulfate, copper sulfate, magnesium chloride, cobalt chloride, granular soda lime, and magnesium perchlorate.

52. The glass cloth package according to claim 49, wherein the moisture absorbent is in the form of a sheet.

53. The glass cloth package according to any one of claims 35 to 38, wherein the interior of the packaging material is filled with dry air having a dew point of 10 °C dp or less, or a gas containing at least one selected from the group consisting of nitrogen, argon, and oxygen and having a dew point of 10 °C dp or less.

54. The glass cloth package according to any one of claims 35 to 38, wherein the interior of the packaging material has a pressure less than atmospheric pressure.

55. The glass cloth package according to any one of claims 35 to 38, wherein the glass cloth is treated with a surface treatment agent containing a silane coupling agent.

56. The surface treatment agent is represented by the following formula (1): X(R) ３－ｎ SiY ｎ ...(1) (In formula (1), X is an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is each independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group) The glass cloth package according to claim 55, containing the silane coupling agent represented by the formula.

57. The glass cloth package according to claim 56, wherein the surface treatment agent contains two or more kinds of silane coupling agents having different Xs in the formula (1).

58. The glass cloth package according to claim 55, wherein the surface treatment agent contains two or more kinds of silane coupling agents having different molecular weights.

59. The glass cloth package according to any one of claims 35 to 38, wherein the dielectric tangent of the glass cloth at 10 GHz is 0.00051 or more and 0.00200 or less.

60. The glass cloth package according to any one of claims 35 to 38, wherein the weft and / or warp insertion density of the glass cloth is in the range of 66 to 120 threads / inch (= 66 to 120 threads / 25 mm).

61. The basis weight (mass of the glass cloth) of the glass cloth is in the range of 8 to 25 g / m ２ The glass cloth package according to any one of claims 35 to 38, wherein the glass cloth package is in the range of.

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