Glass cloth, prepreg, printed wiring board, and surface treatment liquid

Abstract

To provide a glass cloth that exhibits superior dielectric characteristics and suppresses time-dependent increase in dielectric loss tangent.SOLUTION: A glass cloth is constituted by glass yarns each comprising a plurality of glass filaments as warp yarns and weft yarns. The glass cloth has a surface treatment agent on its surface, and the surface treatment agent contains a silane coupling agent having a molecular structure in which a value obtained by the following formula: 1.10×MaxEStateIndex+14.6×MaxPartialCharge-0.0917×SPS+2.47×HallKierAlpha is 15.0 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to glass cloth, prepreg, printed wiring boards, surface treatment liquids, and the like. [Background technology]

[0002] Currently, information terminals such as smartphones are becoming more powerful, and high-speed communications, such as those typified by 5G communications, are becoming more common. Accordingly, in printed wiring boards for high-speed communications, the dielectric constant and dissipation factor of insulating materials used to reduce transmission loss are becoming significantly lower, and higher levels of insulation reliability are also being demanded.

[0003] Examples of insulating materials for printed wiring boards for high-speed communication are reported in Patent Documents 1 and 2. Specifically, Patent Documents 1 and 2 disclose a prepreg obtained by impregnating a glass cloth with a low-dielectric thermosetting resin (hereinafter collectively referred to as "matrix resin") that is crosslinked and cured by a radical reaction, such as polyphenylene ether whose terminals are modified with vinyl or methacryloxy groups, and then drying the resin. Laminates are known that are obtained by stacking the prepregs obtained in this manner and curing them by heating and pressurization. Patent Documents 1 and 2 aim to obtain a laminate with a low dielectric constant and a low dielectric loss tangent using a glass cloth with a low dielectric constant and a low dielectric loss tangent.

[0004] To reduce the dielectric loss tangent of glass cloth, Patent Documents 3 and 4 describe heating silica glass cloth at high temperatures to reduce the amount of silanol groups on the glass surface. Patent Document 5 describes reducing the silanol groups present on the glass cloth surface by surface treatment, thereby reducing the dielectric loss tangent of the glass cloth. Patent Document 6 describes a method for packaging silica glass cloth to prevent the dielectric loss tangent of the silica glass cloth from increasing over time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 065940 [Patent Document 2] International Publication No. 2019 / 065941 [Patent Document 3] Patent Publication No. 2021-63320 [Patent Document 4] Japanese Patent Publication No. 2021-195689 [Patent Document 5] Japanese Patent Application Publication No. 2020-194888 [Patent Document 6] Patent No. 7375902 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a glass cloth that has excellent dielectric properties and is capable of suppressing an increase in dielectric loss tangent over time. Another object of the present disclosure is to provide a method for producing the glass cloth and a surface treatment solution for use with the glass cloth. Finally, an object of the present disclosure is to provide a prepreg, a printed wiring board, and the like that use the glass cloth. [Means for solving the problem]

[0007] Examples of embodiments of the present invention are listed in the following items [1] to

[38] . [1] A glass cloth configured with glass yarns containing a plurality of glass filaments as warp yarns and weft yarns, The glass cloth has a surface treatment agent on its surface, The surface treatment agent is represented by the following formula (A): 1.10×MaxEStateIndex+14.6×MaxPartialCharge-0.0917×SPS+2.47×HallKierAlpha...(A) The glass cloth contains a silane coupling agent having a molecular structure in which the value determined by the above formula is 15.0 or less. [2] 10 white spots / m 2 Item 1. The glass cloth according to item 1, wherein: [3] 3. The glass cloth according to item 1 or 2, wherein the silicon (Si) content in the glass yarn is 95.0 to 100 mass % in terms of silicon dioxide (SiO2). [4] The silane coupling agent is represented by the following general formula (1): X 4-n -Si-Y n ···(1) (In formula (1), each X is independently an organic functional group having at least one selected from an epoxy group, an amino group, and an unsaturated double bond group having radical reactivity; each Y is independently an alkoxy group; and n is an integer of 1 or more and 3 or less.) 4. The glass cloth according to any one of items 1 to 3, comprising a silane coupling agent represented by the formula: [5] 5. The glass cloth according to item 4, wherein X in the general formula (1) contains at least one group selected from the group consisting of an epoxy group, an amino group, an aromatic vinyl group, an acryloyl group, and a methacryloyl group. [6] 6. The glass cloth according to any one of items 1 to 5, wherein the glass cloth has a dielectric loss tangent of 0.002 or less at 10 GHz. [7] 7. The glass cloth according to any one of items 1 to 6, having an ignition loss value in the range of 0.01 to 0.3% by mass. [8] 8. The glass cloth according to any one of items 1 to 7, wherein the value determined by the above formula (A) is 14.4 or less. [9] 9. The glass cloth according to any one of items 1 to 8, wherein the value determined by the above formula (A) is 13.8 or less.

[10] 10. The glass cloth according to any one of items 1 to 9, wherein the value determined by the above formula (A) is 13.5 or less.

[11] 4 white spots / m2 The glass cloth according to any one of items 1 to 10, wherein:

[12] 2 white spots / m 2 12. The glass cloth according to any one of items 1 to 11, wherein:

[13] White spots: 0.1 / m 2 13. The glass cloth according to any one of items 1 to 12, wherein:

[14] White spots 0.05 / m 2 14. The glass cloth according to any one of items 1 to 13, wherein:

[15] 15. The glass cloth according to any one of items 1 to 14, wherein the molecular weight of the silane coupling agent is in the range of 250 to 1,000.

[16] 16. The glass cloth according to any one of items 1 to 15, wherein the molecular weight of the silane coupling agent is in the range of 300 to 750.

[17] 17. The glass cloth according to any one of items 1 to 16, wherein the molecular weight of the silane coupling agent is in the range of 350 to 700.

[18] 18. The glass cloth according to any one of items 1 to 17, which is for a printed wiring board.

[19] A prepreg comprising the glass cloth according to any one of items 1 to 18, a matrix resin, and an inorganic filler.

[20] Item 19. A printed wiring board comprising the prepreg according to item 19. [twenty one] 21. An integrated circuit comprising the printed wiring board according to item 20. [twenty two] 21. An electronic device comprising the printed wiring board according to item 20. [twenty three] A method for producing glass cloth, the method comprising: a step of weaving glass yarns containing a plurality of glass filaments as warp yarns and weft yarns to obtain a glass cloth; The method includes a step of degreasing the glass cloth and then surface-treating the glass cloth with a surface treatment liquid containing a surface treatment agent, The surface treatment agent is represented by the following formula (A): 1.10×MaxEStateIndex+14.6×MaxPartialCharge-0.0917×SPS+2.47×HallKierAlpha...(A) A method for producing glass cloth, comprising: a silane coupling agent having a molecular structure in which the value determined by the above formula (1) is 15.0 or less. [twenty four] The silane coupling agent is represented by the following general formula (1): X 4-n -Si-Y n ···(1) (In formula (1), each X is independently an organic functional group having at least one selected from an epoxy group, an amino group, and an unsaturated double bond group having radical reactivity; each Y is independently an alkoxy group; and n is an integer of 1 or more and 3 or less.) Item 24. The method for producing glass cloth according to Item 23, comprising: [twenty five] Item 25. The method for producing glass cloth according to Item 23 or 24, wherein the surface treatment liquid is prepared by adding an acidic aqueous solution to a hydrolysis solution of the silane coupling agent.

[26] The surface treatment step includes: controlling the temperature and pH of the surface treatment solution; 26. The method for producing glass cloth according to any one of items 23 to 25, comprising filtering the surface treatment liquid.

[27] Item 27. The method for producing a glass cloth according to any one of Items 23 to 26, further comprising a step of subjecting the glass cloth to an opening treatment after the surface treatment step.

[28] Item 28. The method for producing a glass cloth according to any one of Items 23 to 27, further comprising a step of inspecting for white spots after the surface treatment step.

[29] A surface treatment liquid containing a surface treatment agent containing a silane coupling agent, The silane coupling agent is represented by the following formula (A): 1.10×MaxEStateIndex+14.6×MaxPartialCharge-0.0917×SPS+2.47×HallKierAlpha...(A) A surface treatment solution having a molecular structure in which the value determined by the following formula is 15.0 or less.

[30] the surface treatment liquid contains a silane coupling agent in an amount of 0.20 to 1.2 mass % based on the total mass of the surface treatment liquid; the pH of the surface treatment solution is in the range of 2.5 to 5.5; Item 30. The surface treatment liquid according to item 29, wherein the surface treatment liquid contains a surfactant in an amount of 0.5 to 5.0 mass % based on the total mass of the silane coupling agent.

[31] The silane coupling agent is represented by the following general formula (1): X 4-n -Si-Y n ···(1) (In formula (1), each X is independently an organic functional group having at least one selected from an epoxy group, an amino group, and an unsaturated double bond group having radical reactivity; each Y is independently an alkoxy group; and n is an integer of 1 or more and 3 or less.) 31. The surface treatment solution according to Item 29 or 30, comprising:

[32] 32. The surface treatment liquid according to any one of items 29 to 31, wherein the value determined by the above formula (A) is 14.4 or less.

[33] 33. The surface treatment liquid according to any one of items 29 to 32, wherein the value determined by the above formula (A) is 13.8 or less.

[34] 34. The surface treatment liquid according to any one of items 29 to 33, wherein the value determined by the above formula (A) is 13.5 or less.

[35] 35. The surface treatment solution according to any one of items 29 to 34, wherein the pH of the surface treatment solution is in the range of 3.0 to 5.0.

[36] 36. The surface treatment solution according to any one of items 29 to 35, wherein the pH of the surface treatment solution is in the range of 3.0 to 4.0.

[37] 37. The surface treatment liquid according to any one of items 29 to 36, wherein the surface treatment liquid contains a surfactant in an amount of 1.0 to 4.5% by mass based on the total mass of the silane coupling agent.

[38] 38. The surface treatment liquid according to any one of items 29 to 37, wherein the surface treatment liquid contains a surfactant in an amount of 1.5 to 4.0 mass % based on the total mass of the silane coupling agent. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a glass cloth having excellent dielectric properties and capable of suppressing an increase in dielectric loss tangent over time. It is also possible to provide a method for producing the glass cloth and a surface treatment solution for use in the glass cloth. Furthermore, the present disclosure can provide a prepreg, a printed wiring board, and the like, using the glass cloth. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram for explaining a white spot. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described. However, the present invention is not limited to the embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0011] In the present specification, when a plurality of structures represented by the same symbol exist in the same formula, the structures may be independently selected and may be the same or different from each other, unless otherwise specified. When a plurality of structures represented by the same symbol exist in different formulas, the structures may be independently selected and may be the same or different from each other, unless otherwise specified. In the present specification, various measurements are carried out based on the methods described in the Examples unless otherwise specified. In the present specification, the upper or lower limit of a numerical range described in a stepwise manner may be replaced by the upper or lower limit of a corresponding numerical range described in another stepwise manner, and may further be replaced by the corresponding value described in the Examples.

[0012] In this specification, the term "step" includes not only an independent step but also a step that cannot be clearly distinguished from other steps, as long as the function of the step is achieved. In the contents shown in the drawings, the scale, shape, and length may be exaggerated for clarity.

[0013] Glass cloth The glass cloth of the present disclosure is a glass cloth woven from glass yarns, for example, a glass cloth configured with glass yarns containing a plurality of glass filaments as warp and weft yarns. The surface of the glass cloth has a surface treatment agent, and the silane coupling agent contained in the surface treatment agent has a molecular structure in which the value calculated from the following formula (A) is 15.0 or less. 1.10×MaxEStateIndex+14.6×MaxPartialCharge-0.0917×SPS+2.47×HallKierAlpha...(A)

[0014] According to the present disclosure, it is possible to provide a glass cloth that has excellent dielectric properties and can suppress an increase in the dielectric loss tangent over time. The glass cloth of the present disclosure is suitable as a constituent material for producing prepregs, printed wiring boards, integrated circuits, electronic devices, etc. Preferably, the dielectric loss tangent of the glass cloth can be further reduced compared to the conventional techniques described in Patent Documents 1 to 6. Furthermore, it is also possible to suppress an increase in the dielectric loss tangent of the glass cloth over time, preferably without using the technique of packaging the silica glass cloth in a predetermined manner, as described in Patent Document 6.

[0015] After extensive research, the present inventors focused on glass cloth that had been surface-treated after being heated and deoiled at high temperatures. The present inventors discovered for the first time that glass cloth that had been surface-treated with a silane coupling agent having a molecular structure in which the value calculated by the above formula (A) is 15.0 or less after being heated and deoiled at high temperatures has a low dielectric loss tangent and can suppress the increase in the dielectric loss tangent of the glass cloth over time. While not limited by theory, the reason for this is believed to be that the silane coupling agent coats the glass fiber surface, making it less likely to adsorb moisture present in the storage environment. Therefore, for example, it is possible to suppress the increase in the dielectric loss tangent of the glass cloth over time without using special packaging. The technical significance of each parameter will be described later.

[0016] Silane coupling agents are generally applied to glass cloth as a mixture with a solvent, and in this case, it is preferable to use water as the solvent from the viewpoint of reducing environmental impact. However, it has been found that silane coupling agents having a value calculated from formula (A) of 15.0 or less are highly hydrophobic and have extremely poor dispersibility and / or compatibility in water, and therefore are prone to the formation of "white spots" on the glass cloth surface caused by the surface treatment agent. Since white spots can impair the adhesion at the interface between the glass cloth and the resin, it is preferable to provide glass cloth that suppresses white spots and has a dielectric loss tangent lower than that of bulk glass.

[0017] According to a preferred embodiment of the present disclosure, even a surface treatment agent that is poorly dispersible and / or compatible in water, i.e., highly hydrophobic (e.g., a highly hydrophobic silane coupling agent), can be stably dispersed in water to suppress white spots. In this case, it becomes easier to provide a glass cloth with a lower dielectric loss tangent, and it becomes easier to further suppress the increase in the dielectric loss tangent of the glass cloth over time without special packaging. It also becomes easier to provide a glass cloth that can be used to provide a resin substrate with excellent solder heat resistance.

[0018] [Dielectric loss tangent] (Dielectric tangent of glass cloth) The glass cloth of the present disclosure preferably has a dielectric loss tangent of 0.0020 or less at 10 GHz. Such a glass cloth can provide a prepreg and a printed wiring board with improved dielectric properties. From the viewpoint of improving the dielectric properties, the dielectric loss tangent of the glass cloth at 10 GHz is preferably 0.0015 or less, 0.0010 or less, 0.0007 or less, 0.0006 or less, 0.0005 or less, 0.0004 or less, 0.0003 or less, or 0.0002 or less. The dielectric loss tangent of the glass cloth may be greater than 0.

[0019] (Method for measuring dielectric loss tangent of glass cloth) The dielectric loss tangent at 10 GHz of the glass cloth of the present disclosure is measured by a method using a split cylinder resonator (a method using a resonance method), specifically, the method described in the Examples. This method allows for simpler and more accurate measurement than conventional measurement methods in which a substrate is fabricated as a measurement sample and the dielectric properties are evaluated. The reason for this, without being limited by theory, is that the resonance method is suitable for evaluation in the high-frequency range, particularly for evaluating low-loss materials. Known methods for evaluating dielectric properties other than the resonance method include the lumped parameter method and the reflection transmission method. However, the lumped parameter method requires the measurement sample to be sandwiched between two electrodes to form a capacitor, which can be a cumbersome operation. Furthermore, the reflection transmission method has the drawback of being difficult to accurately evaluate the dielectric loss tangent of the measurement sample when evaluating low-loss materials because the port matching characteristics are strongly affected. Based on the above, the dielectric loss tangent of glass cloth can be easily measured simply and accurately by using a method using a resonance method, specifically, the method described in the Examples.

[0020] For glass cloth used in printed wiring boards, particularly glass cloth used in printed wiring boards for high-speed communication, it is preferable that a measuring device for measuring the dielectric properties thereof has a predetermined measurable range. For example, for the dielectric constant (Dk) and the dielectric loss tangent (Df), the measuring device should have a Dk of 1.1 to 50 and a Df of 1.0 × 10, respectively. -6 ~1.0×10 -1 It is preferable that the measurable range is Dk=1.5 to 10 and Df=1.0×10 -5 ~5.0×10 -1 It is more preferable that the measurable range is Dk=2.0 to 5 and Df=5.0×10 -5 ~1.0×10 -2 It is more preferable that the measurable range is .gtoreq..times ...

[0021] Furthermore, the frequency that can be measured by the measuring device for measuring the dielectric properties is preferably 10 GHz or higher, which makes it easier to evaluate the characteristics in the frequency band region, particularly the characteristics in the frequency band region expected when the glass cloth is actually used as a glass cloth for printed wiring boards for high-speed communication.

[0022] The measurement area for dielectric properties is 10 mm 2 It is preferable that it is 15 mm or more. 2 More preferably, it is 20 mm or more. 2 This makes it easier to improve the reliability of the measurement results obtained, and therefore makes it easier to determine whether the measurement results obtained are within a range of preset reference values.

[0023] The thickness of the measurement sample is preferably 3 μm to 300 μm, more preferably 5 μm to 200 μm, and even more preferably 7 μm to 150 μm.

[0024] (bulk dielectric loss tangent) In the glass cloth of the present disclosure, the bulk dielectric loss tangent at 10 GHz of the glass raw materials constituting the glass cloth is measured by a method using a split cylinder resonator (a method using a resonance method), specifically, by the method described in Examples. Here, the glass raw materials may be, for example, glass threads, glass filaments, glass seeds, etc.

[0025] The bulk dielectric loss tangent at 10 GHz is preferably 0.002 or less, more preferably 0.0015 or less, even more preferably 0.001 or less, even more preferably 0.0005 or less, and particularly preferably 0.0004 or less, which makes it easier to achieve excellent dielectric properties.

[0026] [Glass thread] The glass yarn may be composed of a plurality of glass filaments. The glass yarn may be woven as a warp yarn and a weft yarn to produce a glass cloth.

[0027] [Average filament diameter] The average filament diameter of the glass filaments is preferably 2.5 μm to 9.0 μm, more preferably 2.5 μm to 7.5 μm, even more preferably 3.5 μm to 7.0 μm, still more preferably 3.5 μm to 6.0 μm, and particularly preferably 3.5 μm to 5.0 μm.

[0028] [Placement density] The density of the glass yarns (warp and weft) constituting the glass cloth is preferably 10 to 120 yarns / inch (=10 to 120 yarns / 25.4 mm), more preferably 40 to 100 yarns / inch, and even more preferably 45 to 90 yarns / inch.

[0029] [Metsuke] The weight of the glass cloth is preferably 8 to 250 g / m 2 and more preferably 8 to 100 g / m 2 and more preferably 8 to 80 g / m 2 and particularly preferably 8 to 50 g / m 2 is.

[0030] [Glass type] Conventionally, glass cloth used in prepregs (laminates) is typically a glass raw material called E-glass (alkali-free glass). On the other hand, glass raw materials such as L-glass, NE-glass, D-glass, L2-glass, T-glass, silica glass, and quartz glass may be used for the glass cloth of the present disclosure. From the viewpoint of excellent dielectric properties, glass raw materials such as L-glass, L2-glass, silica glass, and quartz glass are preferably used, and among these, silica glass and quartz glass are particularly preferred. Furthermore, from the viewpoint of improving the dimensional stability of laminates containing glass cloth, glass raw materials such as S-glass, T-glass, silica glass, and quartz glass are preferably used, and among these, silica glass and quartz glass are particularly preferred.

[0031] The silicon (Si) content of the glass yarns constituting the glass cloth, calculated as silicon dioxide (SiO2), is preferably 95.0 to 100 mass% or 99.0 to 100 mass%, more preferably 99.5 to 100 mass%, and even more preferably 99.9 to 100 mass%. The SiO2 content of the glass yarns constituting the glass cloth is particularly preferably more than 99.9 mass%. When the Si content is 95.0 mass% or more, it is easy to ensure the dielectric properties of the glass cloth and the dimensional stability of the laminate.

[0032] [Weave structure] Examples of weave structures for the glass cloth include plain weave, sieve weave, satin weave, and twill weave, with plain weave structures being more preferred.

[0033] [Surface treatment agent] The glass cloth has a surface treatment agent on its surface. The surface treatment is carried out, for example, by a method using a surface treatment liquid containing the surface treatment agent. Details will be described later.

[0034] It has been conventionally recognized that the use of a general surface treatment agent (for example, a general silane coupling agent) increases the dielectric loss tangent of the glass cloth and that the dielectric loss tangent of the glass cloth increases over time. As a result of investigations into this issue, the present inventors have found that by treating the glass surface with a highly hydrophobic surface treatment agent (for example, a highly hydrophobic silane coupling agent), the increase in the dielectric loss tangent of the glass cloth due to the surface treatment can be reduced, and that moisture present in the storage environment is less likely to be adsorbed onto the glass surface, making it easier to suppress the increase in the dielectric loss tangent of the glass cloth over time, even without a special moisture-proof packaging form.

[0035] In the present disclosure, a "highly hydrophobic surface treatment agent (highly hydrophobic silane coupling agent)" refers to an agent in which, when an aqueous solution prepared by mixing a surface treatment agent (silane coupling agent) with a 0.3% by mass aqueous solution of acetic acid so that the concentration of the surface treatment agent (silane coupling agent) is 0.8% by mass, is stirred for 3 hours at room temperature of 25°C, the surface treatment agent (silane coupling agent) is not uniformly dispersed as an emulsion in the aqueous solution or is not dissolved. A state in which the surface treatment agent (silane coupling agent) is not uniformly dispersed as an emulsion or is not dissolved means, for example, a state in which the surface treatment agent (silane coupling agent) is separated in the aqueous solution as oil droplets and an oil film.

[0036] (Silane coupling agent) In the present disclosure, the surface treatment agent preferably contains a silane coupling agent, that is, the glass yarns (including glass filaments) constituting the glass cloth are preferably surface-treated with a silane coupling agent.

[0037] The glass cloth according to the present disclosure is surface-treated with a silane coupling agent having a value calculated by the following formula (A) of 15.0 or less: 1.10 × MaxEStateIndex + 14.6 × MaxPartialCharge − 0.0917 × SPS + 2.47 × HallKierAlpha (A)

[0038] MaxEStateIndex, MaxPartialCharge, SPS, and HallKierAlpha included in formula (A) can be calculated by the method described in the Examples. Specifically, they can be calculated using open source software called "RDKit."

[0039] The MaxEStateIndex used in formula (A) is a value that indicates the electronic properties of an atom, calculated based on the atomic charge, bond order, etc. Generally, a higher MaxEStateIndex value of an atom is considered to indicate a higher molecular polarity and hydrogen bonding ability. Furthermore, MaxPartialCharge represents the partial charge of a molecule; a higher value indicates a larger intramolecular dipole moment, making it more likely to polarize. To achieve excellent dielectric properties and suppress the increase in the dielectric loss tangent over time, lower values ​​of MaxEStateIndex and MaxPartialCharge are preferred. This is because glass cloth coated with a silane coupling agent that is highly polarized tends to adsorb moisture from the air, making it difficult to suppress the increase in the dielectric loss tangent of the glass cloth over time without special packaging.

[0040] Furthermore, the SPS used in Equation (A) is an empirical scoring system for expressing the spatial complexity of a compound in a uniform manner and on a highly granular scale for ranking and comparing molecules, with higher values ​​indicating less steric hindrance. Hall-Kier Alpha is a topological index that represents the steric hindrance of a molecule, with higher values ​​indicating greater steric hindrance. These results suggest that the more sterically hindered the glass cloth surface is, the more likely it is to adsorb moisture from the air. This is because the more sterically hindered the silane coupling agent is, the more difficult it is to uniformly chemically modify the glass surface, making the silane coupling agent layer more sparse. This makes it more susceptible to moisture adsorption from the air, leading to an increase in the dielectric loss tangent of the glass cloth over time.

[0041] From the viewpoint of easily achieving excellent dielectric properties and suppressing an increase in the dielectric loss tangent over time, the value calculated from formula (A) is preferably 14.9 or less, more preferably 14.8 or less, even more preferably 14.7 or less, even more preferably 14.6 or less, and particularly preferably 14.4 or less, 14.2 or less, 14.0 or less, or 13.8 or less. The lower limit of the value calculated from formula (A) is not particularly limited, but may be more than 0, 1 or more, 5 or more, or 10 or more.

[0042] The surface treatment agent is, for example, a compound represented by the following formula (1): X 4-n -Si-Y n ···(1) (In formula (1), each X is independently an organic functional group having at least one selected from an epoxy group, an amino group, and a radical-reactive unsaturated double bond group; each Y is independently an alkoxy group; and n is an integer of 1 or more and 3 or less.) When the surface treatment agent contains the silane coupling agent, it becomes easier to suppress an increase in the dielectric loss tangent of the glass cloth over time.

[0043] From the viewpoint of easily improving adhesion to resins, X in formula (1) is more preferably an organic functional group having at least one group selected from the group consisting of an epoxy group, an amino group, an aromatic vinyl group, an acryloyl group, and a methacryloyl group in its structure. Furthermore, the organic functional group is preferably at least one selected from the group consisting of, for example, an aromatic group, an aliphatic group which may be saturated or unsaturated, linear or branched, with or without a cyclic structure, with or without a heteroatom, and a combination thereof. The total number of carbon atoms in X may preferably be 3 to 20, 5 to 18, 6 to 16, or 7 to 14.

[0044] As for the alkoxy group Y, from the viewpoint of stability of the surface treatment of the glass cloth, an alkoxy group having 1 to 5 carbon atoms (1, 2, 3, 4 or 5 carbon atoms) is preferred.

[0045] As the silane coupling agent contained in the surface treatment agent, the silane coupling agent represented by the above formula (1) may be used alone or in combination. For example, two or more silane coupling agents having different X may be used in combination.

[0046] Examples of the silane coupling agent represented by the general formula (1) include 3,6-diethenyl-1-(trimethoxysilyl)naphthalene represented by the following formula: [ka] [4-[2-(trimethoxysilyl)ethyl]phenyl]methyl 2-propenoate represented by the following formula: [ka] 4-(trimethoxysilyl)phenyl 2-propenoate represented by the following formula: [ka] N-ethenyl-N-(2-oxiranylmethoxy)-3-(trimethoxysilyl)-1-propanamine represented by the following formula: [ka] 1-ethenyl-4-[3-(trimethoxysilyl)propoxy]benzene represented by the following formula: [ka] 4-[2-(trimethoxysilyl)ethyl]benzenamine represented by the following formula: [ka] [bicyclo[2.2.1]hept-5-en-2-yl]triethoxysilane represented by the following formula: [ka] 4-[[4-[3-(trimethoxysilyl)propoxy]phenyl]sulfonyl]phenyl 2-methyl-2-propenoate, represented by the following formula: [ka] 6-[[[3-(trimethoxysilyl)propyl]amino]carbonyl]-2-naphthalenyl 2-methyl-2-propenoate, represented by the following formula: [ka] 2-Propenoic acid, 2-methyl-, 2-[(trimethoxysilyl)methyl]-1,3-propanediyl ester represented by the following formula: [ka] Diethoxy(methyl)[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silane represented by the following formula: [ka] Ethoxy(dimethyl)[3-(oxiran-2-ylmethoxy)propyl]silane represented by the following formula: [ka] [2-(bicyclo[2.2.1]hept-5-en-2-yl)ethyl](trimethoxy)silane represented by the following formula: [ka] N-2-propen-1-yl-N-[3-(trimethoxysilyl)propyl]-2-oxiranemethanamine represented by the following formula: [ka] N1-ethenyl-N1-(phenylmethyl)-N2-[3-(trimethoxysilyl)propyl]-1,2-ethanediamine represented by the following formula: [ka] 1-[trans-4-[4-(3-methylbutyl)phenyl]cyclohexyl]-2-(trimethoxysilyl)ethyl 2-methyl-2-propenoate, represented by the following formula: [ka] etc.

[0047] The silane coupling agent that can be used can be adjusted appropriately depending on the matrix resin used in the resin substrate, etc. Of course, a silane coupling agent having a value calculated from the above formula (A) of 15.0 or less may be used in combination with a silane coupling agent other than a silane coupling agent having a value calculated from the above formula (A) of 15.0 or less. On the other hand, it is preferable to use two or more silane coupling agents having different molecular weights and having a value calculated from the above formula (A) of 15.0 or less. Using two or more silane coupling agents having different molecular weights tends to increase the density of the treatment agent on the glass surface, which tends to further improve reactivity with the matrix resin.

[0048] (Molecular weight of silane coupling agent) The molecular weight of the surface treatment agent, for example, the molecular weight of the silane coupling agent, is preferably 250 to 1000, more preferably 270 to 800, even more preferably 300 to 750, and particularly preferably 350 to 700. When two or more surface treatment agents (for example, silane coupling agents) are used, the weighted average of the molecular weights, where the weights are the masses of the respective surface treatment agents, is preferably within the above range, and it is more preferable that the molecular weights of all of the surface treatment agents used are within the above range. For example, when the surface treatment agent is prepared so that silane coupling agents with molecular weights of 300 and 500 are present in amounts of 0.5 mass% and 1.0 mass%, respectively, the weighted average can be calculated as follows: Weighted average value =300×0.5÷(0.5+1.0)+500×1.0÷(0.5+1.0) =433

[0049] [Average opening degree of glass cloth] The average degree of openness of the glass cloth is preferably 35% or more or greater than 36%, more preferably greater than 38%, even more preferably greater than 40%, 45%, 50%, 52%, or 55%, and particularly preferably greater than 57%. When the average degree of openness of the glass cloth is 35% or more, it is easy to prevent air bubbles called voids from remaining in the glass yarn bundle when a resin substrate is produced, which makes it less likely to adversely affect solder heat resistance, insulation reliability, and the like. Note that the silane coupling agent represented by the above formula (1) tends to exhibit relatively strong intermolecular forces, making the glass cloth less susceptible to impregnation with the matrix resin than silane coupling agents other than those represented by the above formula (1). Therefore, for glass cloth surface-treated with the silane coupling agent represented by the above formula (1), the average degree of openness is preferably 35% or more or greater than 36%, from the viewpoint of fully achieving the effect of improving its insulation reliability. The upper limit of the average openness is 85%. If an average degree of opening is to be increased to 85% or more, the opening treatment of the glass cloth must be strengthened, which is likely to cause a deterioration in the fluff quality of the glass cloth.

[0050] [Ignition loss value of glass cloth] The ignition loss value of the glass cloth is preferably 0.01 to 0.3 mass% or 0.02 to 0.27 mass%, more preferably 0.03 to 0.24 mass%, even more preferably 0.03 to 0.20 mass%, and particularly preferably 0.03 to 0.17 mass%, from the viewpoint of easily reducing the dielectric loss tangent of the glass cloth. When the ignition loss value is 0.01 mass% or more, adhesion between the resin and the glass cloth in the resulting prepreg is easily ensured. In this case, heat resistance and insulation reliability are easily ensured when a printed wiring board is produced. When the ignition loss value of the glass cloth is 0.3 mass% or less, it is easy to avoid a situation in which a surface treatment agent (or its residue) physically adheres to the glass cloth surface without forming a chemical bond with the glass cloth, a surface treatment agent (or its residue) that cannot be removed from the glass cloth surface by water washing, and / or modified products thereof are present in large amounts on the glass cloth surface. In this case, it is easy to achieve a low dielectric loss tangent of the glass cloth.

[0051] [White spots on glass cloth] White spots may be observed on the surface of surface-treated glass cloth. These white spots tend to repel the matrix resin used in producing the prepreg, which may result in poor appearance of the resulting prepreg. The cause of these white spots has not been known until now.

[0052] In this regard, the present inventors have clarified that one of the above white spots is an aggregate or a modified product thereof of a highly hydrophobic surface treatment agent (for example, a highly hydrophobic silane coupling agent). In particular, the present inventors have found that a silane coupling agent having a value of 15.0 or less obtained from the above formula (A) is relatively highly hydrophobic, and therefore tends to easily generate aggregates, and that when the solvent in the surface treatment solution contains water, the frequency of white spots occurring on the glass cloth after surface treatment tends to increase (for example, 10.0 spots / m 2 It was revealed that the number of cases was higher than that of the control group.

[0053] In order to suppress white spots, as will be described later, it is preferable to use techniques such as preparing the surface treatment solution by a predetermined method, controlling the temperature and pH of the surface treatment solution, and filtering the surface treatment solution to remove aggregates in the surface treatment solution.

[0054] The frequency of white spots on the glass cloth is preferably 10.0 spots / m 2 Less than or equal to 7.0 particles / m 2 or less, more preferably 4.0 pieces / m 2 More preferably, 2.0 pieces / m or less 2 Less than or equal to 0.1 pieces / m 2 Less than 0.05 pieces / m, particularly preferably 2 This makes it easy to realize a prepreg with excellent appearance.

[0055] <Glass cloth manufacturing method> The present disclosure also provides a manufacturing method for manufacturing the glass cloth of the present disclosure. The manufacturing method of the present disclosure includes a weaving step of weaving glass yarns containing a plurality of glass filaments as warp and weft yarns to obtain a glass cloth, and a surface treatment step of deoiling the glass yarns and then surface-treating the glass yarns with a surface treatment solution containing a surface treatment agent. The surface treatment agent is the surface treatment agent of the present disclosure. The dielectric loss tangent at 10 GHz of the glass cloth after the surface treatment is preferably lower than the dielectric loss tangent at 10 GHz of the glass cloth before the surface treatment.

[0056] wherein the surface treatment step may optionally further include one or more of the following steps: a step of heating the glass yarn to reduce the amount of fiber sizing agent adhering to the glass yarn (thermal deoiling step); A step of washing the glass filaments with water (washing step), and / or The process of opening glass threads (opening process).

[0057] The surface treatment step, the opening step, and the cleaning step may be performed on the glass yarn before the step of weaving the glass yarn to obtain a glass cloth (weaving step), or may be performed on the glass cloth after the weaving step. The order of the thermal deoiling step, the surface treatment step, the opening step, and the cleaning step may be reversed, but the thermal deoiling step should be performed before the surface treatment step. When the cleaning step is performed after the weaving step, the cleaning step can also serve as the opening step by using a high-pressure water spray or the like. The composition of the glass cloth usually does not change before and after the opening step.

[0058] [Heat deoiling process] In this process, by heating the glass yarn, it is possible to reduce, and preferably remove, fiber sizing agents (sizing agents), residues thereof, and modified products thereof that are arbitrarily attached to the glass yarn. By performing the thermal deoiling process, it is possible to form a surface treatment layer on the surface of the glass yarn (glass filament) after reducing organic substances that can increase the dielectric tangent, making it easy to produce glass cloth with excellent dielectric properties. Known means (heating means, heating medium, heating mechanism, heating device, heating component, etc.) can be used as the means for thermal deoiling.

[0059] As one embodiment of the thermal deoiling step, for example, a method in which the glass cloth is heated at a temperature of 600 to 1600°C is known.

[0060] In the heat treatment step, by heating a glass cloth greige having a glass yarn softening point of 900°C or higher in a temperature range of 600 to 1600°C, damage to the glass cloth can be easily suppressed and the dielectric loss tangent of the glass cloth can be easily reduced. From the viewpoint of suppressing an increase in the dielectric loss tangent of the glass cloth over time, it is preferable to sufficiently dehydrate and condense the silanol groups present on the glass surface to an extent that does not adversely affect the subsequent surface treatment step. By reducing the number of silanol groups on the glass surface to a certain amount or less, adsorption of moisture from the air can be suppressed, and as a result, excellent dielectric properties and suppression of an increase in the dielectric loss tangent over time can be easily achieved.

[0061] From the viewpoint of obtaining excellent dielectric properties and suitably suppressing an increase in the dielectric loss tangent over time, the thermal deoiling temperature is preferably 700 to 1500°C, more preferably 800 to 1400°C, even more preferably 900 to 1300°C, and particularly preferably 1000 to 1200°C. When the thermal deoiling temperature is 600°C or higher, sizing agents and the like adhering to the glass cloth green fabric can be easily removed effectively, making it easy to produce glass cloth with excellent dielectric properties. When the thermal deoiling temperature is 1600°C or lower, it is easy to suppress the devitrification phenomenon of the glass, and as a result, it is easy to prevent a decrease in the strength of the glass cloth.

[0062] The heating time is preferably 1 hour or less or 30 minutes or less, more preferably 15 minutes or less, and even more preferably 5 minutes or less. Heating the glass cloth at a high temperature for a sufficient time tends to induce a dehydration condensation reaction of the silanol groups on the glass surface. From the viewpoint of effectively removing the sizing agent, the heating time may be, for example, 1 second or more, 5 seconds or more, 10 seconds or more, or 15 seconds or more.

[0063] When the thermal deoiling of the glass cloth is carried out in a closed system, it is preferable to place the glass cloth in a heating furnace from the viewpoint of suitable heating by a heating means. Also, from the viewpoint of efficient storage space and heating range, it is preferable to heat the glass cloth while storing it in a rolled state. Furthermore, from the viewpoint of increasing the efficiency of removing organic substances and shortening the time required for removing organic substances, it is preferable to heat the glass cloth while transporting it in the heating furnace. The transportation of the glass cloth can be carried out, for example, by a combination of an unwinding mechanism and a winding mechanism.

[0064] When the thermal deoiling of the glass cloth is carried out in an open system, it is preferable to heat the glass cloth while transporting it, from the viewpoint of ensuring a heated area. The transportation of the glass cloth can be carried out, for example, by a combination of an unwinding mechanism and a winding mechanism.

[0065] The mode of the thermal deoiling step is not limited to the above. As another embodiment of the thermal deoiling step, for example, Heating in a vacuum or gas with a dew point of 15°C or less under conditions where the heating amount, expressed as heating temperature (°C) x heating time (h), is 450 (°C·h) or more (provided that the maximum heating temperature is 100-600°C). etc. are also known.

[0066] (Heating means) The heating means may be, for example, a heating furnace, an electric heater, a burner, etc., and among these, a gas single radiant tube burner or an electric heater is preferred. A plurality of different heating means may be combined.

[0067] From the viewpoint of efficiently removing organic matter adhering to the surface of the glass cloth, a continuous system in which the glass cloth is heated by continuously passing it through a heating furnace is preferred over a batch system in which the glass cloth wound around a core is heated at a predetermined atmospheric temperature. A system in which the glass cloth can also be washed continuously using washing water with a low metal ion content, such as reverse osmosis (RO) water or ion-exchanged water, is more preferred.

[0068] When the sodium ions adhering to the glass cloth exceed a predetermined amount, thermal deoiling of the glass cloth at 700°C or higher may result in a decrease in the tensile strength of the glass cloth due to devitrification of the quartz glass. In order to prevent this, washing the glass cloth with water containing 20 ppm or less of sodium ions before thermal deoiling can easily reduce the amount of sodium ions on the glass surface. In this case, devitrification of the quartz glass can be easily prevented even when thermal deoiling is performed at 700°C or higher. Maintaining the strength of the glass cloth after thermal deoiling can easily prevent wrinkles and / or scratches on the glass cloth during the surface treatment process.

[0069] From the viewpoint of suitably obtaining excellent dielectric properties and suppressing an increase in the dielectric loss tangent over time, the sodium ion content of the water used for washing may be 18 ppm or less, 15 ppm or less, 12 ppm or less, 10 ppm or less, or 7 ppm or less. The sodium ion content is preferably 0 ppm, but may exceed 0 ppm.

[0070] The means for cleaning the glass cloth to a sodium ion content of 20 ppm or less may be any known cleaning method as long as it can remove sodium ions from the glass surface. Examples include ultrasonic methods (e.g., methods using an ultrasonic vibrator), spraying (e.g., spraying with a high-pressure spray), and steam spraying. From the viewpoint of low-cost processing, a preferred method involves immersing the glass cloth in a water tank containing cleaning water (water with a sodium ion content of 20 ppm or less), removing excess cleaning water with a squeeze roller, or the like, and then drying the glass cloth. In this case, the immersion time may be, for example, 2 seconds or more, 5 seconds or more, 10 seconds or more, 15 seconds or more, or 120 seconds or less, 90 seconds or less, 60 seconds or less, or 45 seconds or less.

[0071] The method for producing water having a sodium ion content of 20 ppm or less may be a known production method. For example, filtration using an RO membrane or deionization using an ion exchange resin may be used. "Water having a sodium ion content of 20 ppm or less" may contain other liquid components (liquids other than water, etc.) within a range that does not impair the effects of the present invention.

[0072] From the viewpoint of facilitating the dehydration condensation reaction of the silanol groups on the glass surface, it is preferable to make the surrounding environment as moisture-free as possible during the period from thermal deoiling to lowering the temperature of the glass cloth surface to 100°C or less, that is, to reduce the surrounding moisture during thermal deoiling. Methods for reducing the surrounding moisture during thermal deoiling include, for example, A method of introducing dry air into a heating furnace, a method of creating a vacuum inside the furnace, a method of introducing an inert gas such as nitrogen into the furnace, When the thermal deoiling treatment is carried out while the glass cloth is being conveyed, it is preferable to introduce an inert gas such as nitrogen into the furnace.

[0073] [Surface treatment process] In this process, the glass fiber is surface-treated using a surface treatment solution containing a predetermined surface treatment agent, particularly a predetermined silane coupling agent (in one embodiment, a silane coupling agent that is advantageous in terms of reducing the dielectric tangent of the glass cloth). The silane coupling agent used in the method of the present disclosure is more hydrophobic than general silane coupling agents. As described above, the present inventors have discovered that when the solvent in the surface treatment solution contains water, aggregates of the surface treatment agent tend to occur easily, and that when the solvent in the surface treatment solution contains water, the frequency of white spots occurring on the glass cloth after surface treatment tends to increase.

[0074] Methods for treating glass filaments with a surface treatment solution (for example, methods for applying a surface treatment solution to glass filaments) include: (A) A method in which a glass cloth is transported while being immersed in a surface treatment solution stored in a bath (hereinafter referred to as the "immersion method"); (a) A method of directly applying the surface treatment liquid to the glass cloth using a roll coater, die coater, gravure coater, etc. When the immersion method is employed, the immersion time of the glass cloth in the surface treatment solution is preferably selected to be 0.5 seconds or more and 1 minute or less.

[0075] (Surface treatment liquid) The surface treatment solution of the present disclosure is a surface treatment solution containing a surface treatment agent, and can be used for the surface treatment of glass cloth. The surface treatment agent has a molecular structure in which the value calculated from the following formula (A) is 15.0 or less. 1.10×MaxEStateIndex+14.6×MaxPartialCharge-0.0917×SPS+2.47×HallKierAlpha...(A)

[0076] The surface treatment agent contained in the surface treatment liquid preferably contains a silane coupling agent represented by the above formula (1). In the surface treatment step, the glass yarn is preferably treated with a surface treatment liquid containing a surface treatment agent having a molecular weight of 200 or more. Other details of the surface treatment agent are as described above in the section "Glass Cloth."

[0077] The present inventors have found that in a given surface treatment liquid, it is possible to suppress white spots on glass cloth by, for example, one or more of the following methods (A) to (C). (A) preparing a surface treatment liquid by adding an acidic aqueous solution to a hydrolyzed solution of a surface treatment agent; (B) controlling the temperature and / or pH of the surface treatment solution; and / or (C) Filtering the surface treatment solution.

[0078] (A) Preparation of surface treatment solution Because typical silane coupling agents have excellent compatibility with and dispersibility in water, they are prepared by gradually adding a hydrolysis solution of the silane coupling agent (also referred to as a "pre-solution" in the present disclosure) to weakly acidic water with a pH of approximately 3 to 5 while stirring. In contrast, in the method of the present disclosure, a surface treatment solution is preferably prepared by adding an acidic aqueous solution to the silane coupling agent. More preferably, a pre-solution containing the surface treatment agent is prepared, and the acidic aqueous solution is added to the resulting pre-solution. More specifically, a hydrolysis solution of the surface treatment agent (pre-solution) can be obtained by diluting the surface treatment agent with a small amount of methanol, adding a surfactant and a small amount of solvent for hydrolyzing the silane coupling agent (e.g., a 60% aqueous acetic acid solution) to the diluted solution. The solvent in the pre-solution is added to hydrolyze the alkoxide groups of the silane coupling agent, and the amount of solvent added is preferably adjusted depending on the amount of hydrolysis. Then, the acidic aqueous solution (also referred to as a "mother liquor" in the present disclosure) is gradually added to the pre-solution while stirring, thereby uniformly dispersing the surface treatment agent in the aqueous solution. In this case, it is easy to suppress the formation of aggregates in the surface treatment liquid. The acidic aqueous solution used as the mother liquor is preferably a weak acid aqueous solution, for example, a weak acid aqueous solution adjusted to a pH of 2.5 to 5.5, 3.0 to 5.0, 3.0 to 4.5, or 3.0 to 4.0. The weak acid is, for example, a carboxylic acid having the general formula RCOOH, where R is an alkyl group having 1 to 10 carbon atoms, which may be substituted or unsubstituted, linear or branched. Preferably, formic acid, acetic acid, propionic acid, etc. can be used as the weak acid.

[0079] The "small amount of solvent for hydrolyzing the silane coupling agent" may be the acidic aqueous solution used as the mother liquid. Alternatively, the solvent for hydrolyzing the silane coupling agent (for example, a 60% aqueous acetic acid solution) may be used as the mother liquid.

[0080] (Silane coupling agent concentration) In the present disclosure, the concentration of the silane coupling agent in the surface treatment agent is preferably in the range of 0.20 to 1.2 mass%, more preferably 0.25 to 1.1 mass%, even more preferably 0.30 to 1.0 mass%, even more preferably 0.33 to 0.9 mass%, and particularly preferably 0.35 to 0.7 mass%. If the concentration of the silane coupling agent is 1.2 mass% or less, the amount of silane coupling agent attached to the glass cloth surface decreases, resulting in a lower dielectric loss tangent of the glass cloth. If the concentration of the silane coupling agent is 0.2 mass% or more, the amount of silane coupling agent attached to the glass cloth surface increases, improving adhesion to the matrix resin, thereby contributing to improved performance of the laminate, such as heat resistance.

[0081] The surfactant may be selected from a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant, and different types of surfactants may be used in combination.

[0082] Examples of nonionic surfactants include glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene glycols, fatty acid polyethylene glycols, fatty acid polyoxyethylene sorbitan, and fatty acid alkanolamides.

[0083] Examples of anionic surfactants include fatty acid monocarboxylates, polyoxyethylene alkyl ether carboxylates, N-acylsarcosinates, N-acylglutamates, dialkyl sulfosuccinates, alkanesulfonates, alpha-olefin sulfonates, linear alkylbenzenesulfonates, alkylbenzenesulfonates, naphthalenesulfonate-formaldehyde condensates, alkylnaphthalenesulfonates, N-methyl-N-acyltaurates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fat and oil sulfate esters, alkyl phosphates, polyoxyethylene alkyl ether phosphates, and polyoxyethylene alkyl phenyl ether phosphates.

[0084] Examples of cationic surfactants include monoalkylamine salts, dialkylamine salts, trialkylamine salts, alkyltrimethylammonium chloride, and alkylbenzalkonium chloride.

[0085] Examples of amphoteric surfactants include 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, alkyl betaine, fatty acid amidopropyl betaine, alkyldiethylenetriaminoacetic acid, and alkylamine oxide.

[0086] (Concentration of surfactant) In the present disclosure, the concentration of the surfactant in the surface treatment solution is preferably in the range of 0.5 to 5.0 mass% relative to the silane coupling agent. It is more preferably 1.0 to 4.5 mass%, even more preferably 1.5 to 4.0 mass%, even more preferably 1.8 to 3.7 mass%, and particularly preferably 2.0 to 3.5 mass%. When the concentration of the surfactant is 5.0 mass% or less relative to the silane coupling agent, the amount of surfactant remaining on the glass cloth surface is reduced, improving the CAF resistance of the laminate. When the concentration of the surfactant is 0.5 mass% or more relative to the silane coupling agent, the water dispersibility of the silane coupling agent is improved, reducing the frequency of white spots to 10 spots / m. 2 This makes it easier to control.

[0087] (B) Temperature control and / or pH control of the surface treatment solution From the viewpoint of suppressing aggregation in the surface treatment solution, it is preferable to have a step of controlling the temperature of the surface treatment solution during the surface treatment. The temperature is preferably controlled within a range of 10 to 30°C, more preferably 13 to 27°C, even more preferably 15 to 25°C, and particularly preferably 17 to 23°C.

[0088] Furthermore, during the surface treatment, the pH of the surface treatment solution may fluctuate due to impurities such as alkali metals contained in trace amounts in the glass cloth. From the viewpoint of suppressing agglomeration in the surface treatment solution, it is preferable to have a step of controlling the pH of the surface treatment solution. During the surface treatment process, the pH of the surface treatment solution is controlled preferably to 2.5 to 5.5, more preferably 2.8 to 5.2, and even more preferably 3.0 to 5.0, 3.0 to 4.5, or 3.0 to 4.0. Examples of methods for controlling the pH within a predetermined range include bubbling carbon dioxide into the surface treatment solution.

[0089] Either one of the temperature control and the pH control of the surface treatment liquid may be performed, or both may be performed. From the viewpoint of suitably suppressing the formation of aggregates in the surface treatment liquid, it is preferable to perform both the temperature control and the pH control of the surface treatment liquid.

[0090] Here, "temperature control of the surface treatment liquid" is a concept that includes not only an operation of raising and / or lowering the temperature of the surface treatment liquid, but also an operation of maintaining the temperature of the surface treatment liquid at a predetermined value, and an operation of detecting the temperature to determine whether the temperature of the surface treatment liquid is within a predetermined range. Also, "pH control of the surface treatment liquid" is a concept that includes not only an operation of raising and / or lowering the pH of the surface treatment liquid, but also an operation of maintaining the pH of the surface treatment liquid at a predetermined value, and an operation of detecting the pH to determine whether the pH of the surface treatment liquid is within a predetermined range.

[0091] (C) Filtration of surface treatment solution From the viewpoint of reliably collecting aggregates in the surface treatment liquid, it is preferable to filter the surface treatment liquid during the surface treatment. At this time, it is preferable to collect aggregates that may occur in the surface treatment liquid by filtration while circulating the surface treatment liquid.

[0092] From the viewpoint of increasing the efficiency of collecting the aggregates, it is preferable to perform filtration in multiple stages. For example, two-stage filtration is preferable, in which the aggregates are first removed using a filter with a relatively coarse mesh, and then the surface treatment liquid is filtered again using a filter with a finer mesh than the primary filter. Such multiple-stage filtration makes it easy to prevent clogging of the filter, and as a result, it is easy to avoid interruptions in the glass cloth production process.

[0093] (drying process) The surface treatment step may further include a step (drying step) of drying the solvent contained in the surface treatment solution after applying the surface treatment solution to the glass fiber. The drying step makes it easy to fix the surface treatment agent to the surface of the glass fiber (surface of the glass filaments), and in particular, makes it easy to fix the surface treatment agent to the surface of each individual glass fiber (surface of each individual glass filament). Examples of methods for drying the solvent include known methods such as drying by heating, specifically, methods of heating and drying by hot air, electromagnetic waves, etc.

[0094] The drying temperature is preferably 80° C. or higher, more preferably 90° C. or higher, from the viewpoint of sufficiently reacting the surface treatment agent with the glass, and is preferably 300° C. or lower, more preferably 180° C. or lower, from the viewpoint of preventing deterioration of the organic functional groups of the surface treatment agent.

[0095] [Opening process] The manufacturing method of the present disclosure preferably includes a fiber-opening step after the surface treatment step. Examples of the fiber-opening method in the fiber-opening step include a method of opening the glass cloth with spray water (high-pressure water opening), a vibro washer, ultrasonic water, a mangle, or the like. By reducing the tension applied to the glass cloth during this fiber-opening process, the width of the glass yarns can be easily increased and the surface treatment agent that has not chemically bonded to the glass surface can be easily removed to some extent. In order to prevent a decrease in the tensile strength of the glass cloth due to the fiber-opening process, it is preferable to take measures such as reducing the friction of contacting members when weaving the glass yarns, optimizing the sizing agent and increasing the amount of adhesion.

[0096] [Cleaning process] The washing step is preferably a method capable of reducing residues of the surface treatment agent that are not chemically bonded to the surface of the glass filaments, modified substances, etc., such as a method of washing the glass filaments with an organic solvent. By carrying out the washing step, even if a glass raw material with a high silicon (Si) content, such as quartz glass, is used, it becomes easier to adjust the difference between the dielectric loss tangent and bulk dielectric loss tangent of the obtained glass cloth to within a predetermined range.

[0097] In the washing step, washing with a highly hydrophobic organic solvent is preferred in order to reduce the above-mentioned residues that are difficult to reduce with water, and washing with an organic solvent that has a high affinity for silane coupling agent residues having hydroxyl groups is also preferred. Examples of washing methods include known methods such as immersion and shower spraying, and washing may be performed while heating or cooling as necessary. To prevent dissolved substances from re-adhering to the glass cloth, it is preferred to reduce excess solvent from the washed glass cloth using a squeeze roller or the like before drying. Suitable organic solvents, for example, highly hydrophobic organic solvents, include saturated chain aliphatic hydrocarbons such as n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, n-octane, i-octane, 2,2,4-trimethylpentane (isooctane), n-nonane, i-nonane, n-decane, i-decane, and 2,2,4,6,6-pentamethylheptane (isododecane); saturated cyclic aliphatic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, and ethylcyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, and triethylbenzene; and halogen-containing solvents such as chloroform, dichloromethane, and dichloroethane.

[0098] Examples of organic solvents that have a high affinity for modified surface treatment agents (e.g., silane coupling agents) include alcohols such as methanol, ethanol, and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as methyl ethyl ether and diethyl ether; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; dimethyl sulfoxide; and the like.

[0099] Among the above, aromatic hydrocarbons, alcohols or ketones are preferred, and methanol is more preferred, from the viewpoint of easily adjusting the difference between the dielectric loss tangent and bulk dielectric loss tangent of the resulting glass cloth to fall within a predetermined range.

[0100] The manufacturing method of the present disclosure preferably includes a step of drying the washed glass cloth (post-washing drying step) in order to reduce the amount of organic solvent after washing, and from the viewpoint of facilitating reduction of the organic solvent by drying, the organic solvent used for washing preferably has a boiling point of 120° C. or lower. Known methods such as heat drying and air drying can be used to dry the organic solvent.

[0101] When heat drying is performed to reduce the amount of organic solvent in the post-wash drying step, hot air drying using low-pressure steam or heat transfer oil as a heat source is preferred from a safety standpoint. The drying temperature is preferably equal to or higher than the boiling point of the washing solvent, and is preferably 180°C or lower from the standpoint of suppressing deterioration of the silane coupling agent.

[0102] [Optional step] The manufacturing method of the present disclosure may optionally include other steps in addition to the steps described above, such as a step of processing the glass cloth into slits (slit processing step).

[0103] (Inspection process or measurement process) Further, as another step, a step of inspecting the glass cloth for white spots can be mentioned. By including such a step, the manufacturing method of the present disclosure can easily realize the glass cloth of the present disclosure.

[0104] Prepreg The prepreg of the present disclosure contains glass cloth, a matrix resin, and an inorganic filler. The prepreg of the present disclosure can use the glass cloth of the present disclosure as the glass cloth. This provides a prepreg with excellent properties (for example, a prepreg with few voids).

[0105] The matrix resin may be either a thermosetting resin or a thermoplastic resin, and may be used in combination with a thermosetting resin and a thermoplastic resin.

[0106] Examples of thermosetting resins include: a) an epoxy resin obtained by reacting a compound having an epoxy group with a compound having at least one group reactive with the epoxy group, such as an amino group, a phenol group, an acid anhydride group, a hydrazide group, an isocyanate group, a cyanate group, or a hydroxyl group, without a catalyst or with the addition of a catalyst having a reaction catalytic ability, such as an imidazole compound, a tertiary amine compound, a urea compound, or a phosphorus compound, followed by curing; b) a radical polymerization type curable resin obtained by curing a compound having at least one of an allyl group, a methacryl group, and an acrylic group using a thermal decomposition type catalyst or a photodecomposition type catalyst as a reaction initiator; c) a maleimide triazine resin obtained by reacting a compound having a cyanate group with a compound having a maleimide group and curing the resulting mixture; d) a thermosetting polyimide resin obtained by reacting and curing a maleimide compound with an amine compound; e) a benzoxazine resin obtained by crosslinking and curing a compound having a benzoxazine ring through thermal polymerization; Examples include:

[0107] Examples of thermoplastic resins include polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide, polysulfone, polyether sulfone, polyarylate, aromatic polyamide, polyether ether ketone, thermoplastic polyimide, insoluble polyimide, polyamide imide, LCP, polyester, and fluororesin.

[0108] The prepreg may contain an inorganic filler. Examples of the inorganic filler include aluminum hydroxide, zirconium oxide, calcium carbonate, alumina, mica, aluminum carbonate, magnesium silicate, aluminum silicate, silica, talc, short glass fiber, aluminum borate, and silicon carbide. The inorganic filler may be used in combination with the thermosetting resin.

[0109] <Printed wiring board> The printed wiring board of the present disclosure includes a prepreg. In particular, the printed wiring board of the present disclosure can be formed by using the prepreg of the present disclosure as the prepreg. This provides a printed wiring board with excellent properties (for example, a printed wiring board with excellent insulation reliability).

[0110] Integrated circuits and electronic devices The integrated circuit of the present disclosure includes the printed wiring board of the present disclosure. Furthermore, the electronic device of the present disclosure includes the printed wiring board of the present disclosure. These provide an integrated circuit and an electronic device with various excellent characteristics. Examples of the electronic device include information terminals such as smartphones, and the integrated circuit can be used to improve the performance of the electronic device and to achieve high-speed communications, such as 5G communications. [Example]

[0111] The present disclosure will be described below with reference to examples and comparative examples. However, the present disclosure is not limited to the following examples. Regarding the examples and comparative examples, various productions, measurements, evaluations, etc. were performed by the following methods.

[0112] <<Measurement and Evaluation Methods>> [Calculation of Formula A] The formula (A) of the silane coupling agent was determined by the following procedure. (1) MaxEStateIndex, MaxPartialCharge, SPS, and HallKierAlpha included in equation (A) were calculated using open source software called RDKit. The version of RDKit used was 2023.09.4. (2) Silane coupling agent X, which is a silane coupling agent represented by the following structure, in which the alkoxy group or halogen group (-Y) is converted to a hydroxy group (-OH) to convert it into a silanol structure. 4-n -Si(OH) n was created. Silane coupling agent: X 4-n -Si-Y n Each X is independently an organic functional group, n is an integer of 1 to 3, and each Y is independently an alkoxy group or a halogen group. (3) The silane coupling agent converted into the silanol structure prepared in step (2) was converted into a chemical structure in SMILES notation (simplified molecular input line entry system), which is a string of alphanumeric characters and symbols in ASCII code. (4) For the structure in SMILES notation created in operation (3), a MOL object was created using the MolFromSmiles method in the rdkit.Chem.rdmolfiles module in the RDKit. (5) The descriptor MaxEStateIndex was calculated for the MOL object created in operation (4) using the MaxEStateIndex method of the rdkit.Chem.EState.EState module in the RDKit. (6) The descriptor MaxPartialCharge was calculated for the MOL object created in operation (4) using the MaxPartialCharge method in the rdkit.Chem.Descriptors module in the RDKit. (7) The descriptor SPS was calculated for the MOL object created in operation (4) using the SPS method in the rdkit.Chem.SpatialScore module in the RDKit. (8) The descriptor HallKierAlpha was calculated for the MOL object created in operation (4) using the HallKierAlpha method of the rdkit.Chem.GraphDescriptors module in the RDKit.

[0113] (Linear sum of MaxEStateIndex, MaxPartialCharge, SPS, HallKierAlpha) Using the values ​​of MaxEStateIndex, MaxPartialCharge, SPS, and HallKierAlpha obtained by the above operation, the linear sum of the values ​​of these descriptors was calculated according to the following formula. 1.10×MaxEStateIndex+14.6×MaxPartialCharge-0.0917×SPS+2.47×HallKierAlpha

[0114] [Thickness] The thickness of the glass cloth was measured using a micrometer in accordance with 7.10 of JIS R 3420, by gently rotating the spindle to lightly contact the surface parallel to the measurement surface and reading the scale after the ratchet made three clicks. JIS R 3420 also specifies general test methods for long glass fibers and products such as glass cloth that use long glass fibers.

[0115] [Metsuke] The glass cloth was cut to a predetermined size to obtain a sample. The mass of the sample was divided by the area of ​​the sample to determine the basis weight. Here, the glass cloth was cut to a size of 10 cm x 10 cm to obtain a sample, and the mass was measured to determine the basis weight (g / m 2 ) was sought.

[0116] [Converted thickness] Since glass cloth is a discontinuous planar body made of air and glass, the converted thickness required for measurement by the resonance method was calculated by dividing the basis weight of each glass cloth by the density of the glass. The calculation formula is as follows: Converted thickness (μm) = basis weight (g / m 2 ) ÷ glass density (g / cm 3 ) As follows.

[0117] [Dielectric loss tangent] The dielectric loss tangent of each glass cloth was measured in accordance with IEC 62562. Specifically, glass cloth samples were cut to the size required for measurement with each split cylinder resonator and stored in a constant temperature and humidity oven at 23°C and 50% RH for 8 hours to condition the humidity. The dielectric properties at 10 GHz were then measured using a split cylinder resonator (EM Lab) and an impedance analyzer (Agilent Technologies). Measurements were performed five times for each sample, and the average value was calculated. The dielectric loss tangent of the glass cloth was calculated using the converted thickness for each sample. The bulk dielectric loss tangent of the glass was calculated using a split cylinder from the thickness of a glass plate with the same composition as the glass cloth. IEC 62562 specifies a method for measuring the dielectric properties of fine ceramic materials for dielectric substrates, primarily used in microwave circuits, in the microwave band.

[0118] [Increase in dielectric loss tangent over time] The moisture present in the storage environment can increase the dielectric loss tangent of the glass cloth. Using a thermo-hygrostat, glass cloth was stored in a high-temperature, high-humidity environment (40°C, relative humidity 90%) for one week, and the increase in the dielectric loss tangent before and after storage (dielectric loss tangent after storage - dielectric loss tangent before storage) was determined. (conditions) Storage conditions: 40°C x 90% RH Storage period: 1 week Dielectric loss tangent: Measurement method described above in [Dielectric loss tangent]

[0119] [Ignition loss value] The ignition loss value of the glass cloth was determined in accordance with JIS R3420. Specifically, the glass cloth was dried at a temperature of 110°C ± 5°C for 60 minutes. The test piece was then transferred to a desiccator and allowed to cool at room temperature for 20 minutes, after which the mass of the test piece was measured to the nearest 0.1 mg (A mg). The dried test piece was then heat-treated at a temperature of 625°C ± 20°C for 20 minutes. The test piece was then transferred to a desiccator and allowed to cool for 20 minutes, after which the mass of the test piece was measured to the nearest 0.1 mg (B mg). The ignition loss value was determined using the following formula, rounded to the fourth decimal place, and expressed to the third decimal place. Ignition loss (%) = [{A (mg) - B (mg)} / A (mg)] x 100

[0120] [Average opening degree] The opening degree of the warp yarn of the glass cloth is calculated by the following formula: Warp opening rate (%) = [warp width (μm) / {number of warp filaments × warp filament diameter (μm)}] × 100 It was calculated by: The degree of opening of the weft yarn of the glass cloth was calculated using the following formula: Weft opening rate (%) = [weft width (μm) / {number of weft filaments × weft filament diameter (μm)}] × 100 It was calculated by:

[0121] Using the calculated warp yarn opening rate (%) and weft yarn opening rate (%), the following formula: Average opening rate (%) = {opening rate of warp yarn (%) + opening rate of weft yarn (%)} / 2 The average degree of opening was calculated by the above.

[0122] (Number of warp and weft filaments) In calculating the average degree of opening, the number of filaments in each of the warp and weft yarns was determined by observing a cross-sectional image of the glass yarn. Specifically, a cross-sectional image of the glass yarn as the warp yarn (or the weft yarn) was obtained, and the number of filaments in the warp yarn (or the weft yarn) was measured in the cross-sectional image. Similarly, the image acquisition of the glass yarn and the measurement of the number of filaments were repeated, and the average value of the five measurements obtained was used as the number of filaments in the warp yarn (or the weft yarn).

[0123] (Warp width and weft width) To calculate the average degree of opening, the warp width and weft width were determined by the following method. First, five glass cloth test pieces, each 70 mm in the warp direction and 70 mm in the weft direction, were cut out from the glass cloth. Each of the cut test pieces was observed vertically at 100x magnification using a macroscope. For each test piece, the widths of 250 warp threads (or weft threads) were measured at random, and the average value of the widths of the 250 warp threads (or weft threads) was calculated. The calculated average value was used as the warp width (or weft width).

[0124] <Glass cloth manufacturing example> [Glass Cloth P] The warp and weft yarns were composed of glass yarns with an SiO2 composition of more than 99.9% by mass. Specifically, the warp and weft yarns used were glass yarns with an average filament diameter of 5.0 μm, 100 filaments, and a twist of 1.0Z. Then, using an air jet loom, 2000 m of glass cloth with a plain weave structure was woven, with a warp density of 66 / 25 mm and a weft density of 68 / 25 mm, and a cloth width of 1300 mm. The bulk dielectric loss tangent of the glass constituting the glass yarns used was 0.00020 at 10 GHz.

[0125] [Glass Cloth Q] The warp and weft yarns were composed of glass yarns with an SiO2 composition of more than 99.9% by mass. Specifically, the warp and weft yarns used were glass yarns with an average filament diameter of 5.0 μm, 200 filaments, and a twist of 1.0Z. Then, using an air jet loom, 2000 m of glass cloth with a plain weave structure was woven, with a warp density of 54 / 25 mm and a weft density of 54 / 25 mm, and a cloth width of 1300 mm. The bulk dielectric loss tangent of the glass constituting the glass yarns used was 0.00020 at 10 GHz.

[0126] [Glass Cloth R] The warp and weft yarns were composed of glass yarns with an SiO2 composition of more than 99.9% by mass. Specifically, the warp and weft yarns used were glass yarns with an average filament diameter of 4.0 μm, 50 filaments, and a twist of 1.0Z. Then, using an air jet loom, 2000 m of glass cloth with a plain weave structure was woven with a warp density of 95 / 25 mm and a weft density of 95 / 25 mm, and a cloth width of 1300 mm. The bulk dielectric loss tangent of the glass constituting the glass yarns used was 0.00020 at 10 GHz.

[0127] <Preparation example of surface treatment solution> [Preparation Method I: Adding Mother Liquor to Silane Coupling Agent Pre-Solution] The surface treatment liquid was prepared by the following methods 1) to 6). 1) The silane coupling agent was weighed. 2) Methanol in the same amount as that weighed out in 1) above was mixed with the silane coupling agent weighed out in 1) above to prepare a silane coupling agent solution. 3) The silane coupling agent solution and 0.8% by mass of polyoxyethylene alkyl ether based on the mass of the silane coupling agent weighed in 1) above were mixed and stirred for 1 minute. 4) To the silane coupling agent solution stirred in 3), an aqueous solution of acetic acid with a concentration of 60% by mass was added so that the concentration was 20% by mass based on the mass of the silane coupling agent weighed in 1), thereby obtaining a pre-solution (hydrolyzed solution) containing hydrolyzed silane coupling agent. 5) A mother liquor of an aqueous acetic acid solution (pH = 3-4) was prepared. The pre-solution of the silane coupling agent obtained in 4) above was stirred for 15 minutes at room temperature of 20-25°C. The mother liquor was added to the stirring pre-solution of the silane coupling agent, thereby dispersing the silane coupling agent. The amount and rate of addition of the mother liquor were set so that the addition of the entire amount of the mother liquor was completed within 10 minutes. 6) After step 5), the silane coupling agent solution was stirred at room temperature of 20 to 25° C. for 2 hours to obtain a surface treatment liquid.

[0128] [Preparation Method II: Addition of a silane coupling agent pre-solution to the mother liquor] The surface treatment liquid was prepared by the following methods 1) to 6). 1) The silane coupling agent was weighed. 2) Methanol in the same amount as that weighed out in 1) above was mixed with the silane coupling agent weighed out in 1) above to prepare a silane coupling agent solution. 3) The silane coupling agent solution and 0.8% by mass of polyoxyethylene alkyl ether based on the mass of the silane coupling agent weighed in 1) above were mixed and stirred for 1 minute. 4) To the silane coupling agent solution stirred in 3) above, an aqueous solution of acetic acid with a concentration of 60% by mass was added so that the concentration was 20% by mass based on the mass of the silane coupling agent weighed in 1) above. This gave a pre-solution (hydrolyzed solution) containing hydrolyzed silane coupling agent. 5) A mother solution of acetic acid (pH = 3-4) was prepared. The pre-solution of the silane coupling agent obtained in 4) above was stirred for 15 minutes at room temperature of 20-25°C. At this time, the stirred pre-solution of the silane coupling agent was added to the mother solution, thereby dispersing the silane coupling agent. The amount and rate of addition of the pre-solution were set so that the addition of the entire amount of the pre-solution was completed in 10 minutes. 6) After step 5), the silane coupling agent solution was stirred at room temperature of 20 to 25° C. for 2 hours to obtain a surface treatment liquid.

[0129] Examples and Comparative Examples [Example of glass cloth manufacturing] Example 1 The glass cloth P was washed with ion-exchanged water and then dried. This removed alkali metal ions and other substances adhering to the surface of the glass cloth. Thereafter, the glass cloth was heated and deoiled for 30 seconds in a furnace adjusted to a set temperature of 700°C while being conveyed (thermal deoiling step).

[0130] A surface treatment liquid was prepared by the above-mentioned Preparation Method I using 3,6-diethenyl-1-(trimethoxysilyl)naphthalene (CAS NO: 2230040-75-0, molecular weight = 300.42, silane coupling agent A) represented by the following formula as a silane coupling agent so that the concentration of the silane coupling agent in the surface treatment liquid was 0.35 mass%. [ka]

[0131] The glass cloth after heat deoiling was immersed in the obtained surface treatment solution. Then, excess surface treatment solution was squeezed out with an NBR rubber roll at a pressure of 0.3 MPa. Thereafter, the glass cloth was heated and dried at 130°C for 1 minute, thereby fixing the silane coupling agent to the surface of the glass cloth.

[0132] In this example, during the surface treatment of the glass cloth, temperature control (e.g., cooling) was performed so that the temperature of the surface treatment liquid was in the range of 17 to 23° C. Furthermore, during the surface treatment of the glass cloth, carbon dioxide was bubbled into the surface treatment liquid so that the pH of the surface treatment liquid was in the range of 3.0 to 4.0.

[0133] In this example, the surface treatment solution used for the surface treatment of the glass cloth was filtered using an HDCII filter (manufactured by Nippon Pall Co., Ltd.). That is, the surface treatment solution was first passed through a filter with a mesh size of 10 μm, and then passed through a filter with a mesh size of 4.5 μm. This allowed for the collection of aggregates that may be present in the surface treatment solution. The filtered surface treatment solution was used for the surface treatment of the glass cloth.

[0134] After surface treatment, the spray nozzle was used to spray 3.5 kg / cm onto the glass cloth. 2 Then, in water, the fiber was opened at a frequency of 25 kHz and an output of 0.40 W / cm. 2The glass cloth was further opened by irradiating it with ultrasonic waves at 1000 Hz, reducing the excess silane coupling agent that had physically adhered to the glass cloth. It was then dried by heating at 130°C for 1 minute. As a result, 2000 m of surface-treated glass cloth was obtained.

[0135] Example 2 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that [4-[2-(trimethoxysilyl)ethyl]phenyl]methyl 2-propenoate (CAS NO: 141813-20-9, molecular weight = 310.42, silane coupling agent B) represented by the following formula was used as the silane coupling agent. [ka]

[0136] Example 3 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that 4-(trimethoxysilyl)phenyl 2-propenoate (CAS NO: 220369-00-6, molecular weight = 268.34, silane coupling agent C) represented by the following formula was used as the silane coupling agent. [ka]

[0137] Example 4 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that N-ethenyl-N-(2-oxiranylmethoxy)-3-(trimethoxysilyl)-1-propanamine (CAS NO: 142177-48-8, molecular weight = 277.39, silane coupling agent D) represented by the following formula was used as the silane coupling agent. [ka]

[0138] Example 5 2000 m of surface-treated glass cloth was obtained in the same manner as in Example 1, except that 1-ethenyl-4-[3-(trimethoxysilyl)propoxy]benzene (CAS NO: 149738-31-8, molecular weight = 282.41, silane coupling agent E) represented by the following formula was used as the silane coupling agent. [ka]

[0139] Example 6 A surface-treated glass cloth of 2000 m was obtained in the same manner as in Example 1, except that 4-[2-(trimethoxysilyl)ethyl]benzeneamine (CAS NO: 56926-97-7, molecular weight = 241.36, silane coupling agent F) represented by the following formula was used as the silane coupling agent. [ka]

[0140] Example 7 A surface-treated glass cloth of 2000 m was obtained in the same manner as in Example 1, except that [bicyclo[2.2.1]hept-5-en-2-yl]triethoxysilane (CAS NO: 18401-43-9, molecular weight = 256.41, silane coupling agent G) represented by the following formula was used as the silane coupling agent. [ka]

[0141] Example 8 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that the glass cloth Q was used instead of the glass cloth P and the concentration of the silane coupling agent in the surface treatment liquid was changed to 0.25 mass %.

[0142] Example 9 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that Glass Cloth R was used instead of Glass Cloth P and the concentration of the silane coupling agent in the surface treatment liquid was 0.25 mass %.

[0143] Example 10 A glass cloth of 2000 m was obtained in the same manner as in Example 1, except that the surface treatment was carried out without filtering the surface treatment solution.

[0144] Example 11 A glass cloth of 2000 m was obtained in the same manner as in Example 1, except that the surface treatment solution was not cooled even when the temperature exceeded 23°C, and carbon dioxide was not bubbled even when the pH exceeded 4.0.

[0145] Example 12 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that the concentration of the silane coupling agent in the surface treatment liquid was set to 0.75 mass %.

[0146] Example 13 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that the concentration of the silane coupling agent in the surface treatment liquid was set to 1.1 mass %.

[0147] (Comparative Example 1) A surface-treated glass cloth of 2000 m was obtained in the same manner as in Example 1, except that 3-(trimethoxysilyl)propyl methacrylate (CAS NO: 2530-85-0, molecular weight = 248.35, silane coupling agent H) was used as the silane coupling agent.

[0148] (Comparative Example 2) A surface-treated glass cloth of 2000 m was obtained in the same manner as in Example 1, except that 5-hexenyl trimethoxysilane (CAS NO: 58751-56-7, molecular weight = 204.34, silane coupling agent I) was used as the silane coupling agent.

[0149] Example 14 2000 m of glass cloth was obtained in the same manner as in Example 1, except that the surface treatment liquid was prepared by the above-mentioned preparation method II, the surface treatment of the glass cloth was carried out without filtering the surface treatment liquid, the surface treatment liquid was not cooled even when the temperature of the surface treatment liquid exceeded 23°C, and carbon dioxide bubbling was not carried out even when the pH exceeded 4.0.

[0150] [Frequency of white spots] On a roll-to-roll inspection table, a tension of 100 N / 1300 mm was applied to the glass cloth and a halogen lamp was irradiated, while the number of white spots occurring on the glass cloth was counted over a length of 2000 m. Then, from the inspection area and the number of white spots found by the inspection, the following formula was used: White spot occurrence frequency (pieces / m 2 ) = Number of white spots / {Width of glass cloth (m) × Inspected length of glass cloth (m)} The frequency of occurrence of white spots was calculated according to the following formula.

[0151] Figure 1 is a photograph for explaining the "white spot" in the present disclosure. Of these, Figure 1(a) shows a photograph of a portion without a white spot, and Figure 1(b) shows a photograph of a portion with a white spot P. In the present disclosure, a white outline is observed upon irradiation with UV light, and the area enclosed by the outline (the area including the outline) is 0.8 cm2. 2 The above defects are defined as "white spots." Here, the contour is, for example, circular. The area enclosed by the contour line was calculated using known image analysis software.

[0152] [Prepreg Production Example 1] In Production Example 1, polyphenylene ether resin was used as the raw material. Specifically, 45 parts by mass of polyphenylene ether (SABIC, Noryl SA9000), 10 parts by mass of triallyl isocyanurate, 45 parts by mass of toluene, and 0.6 parts by mass of 1,3-di(tert-butylisopropylbenzene) were added to a stainless steel container and stirred at room temperature for 1 hour. This produced a varnish. The glass cloths obtained in Examples 1 to 3, 5, 7, 8 to 14, and Comparative Examples 1 and 2 were impregnated with the varnish and then dried at 130°C for 1 minute to produce a prepreg.

[0153] [Prepreg Production Example 2] In Production Example 2, epoxy resin was used as a raw material. Specifically, a varnish was prepared by blending 80 parts by mass of low-brominated bisphenol A epoxy resin, 20 parts by mass of cresol novolac epoxy resin, 2 parts by mass of dicyandiamide, 0.2 parts by mass of 2-ethyl-4-methylimidazole, and 100 parts by mass of 2-methoxyethanol. The glass cloth obtained in Examples 4 and 6 was impregnated with the prepared varnish and then dried at 130°C for 7 minutes to obtain a prepreg.

[0154] [Production Example of Polyphenylene Ether Resin Substrate] The obtained prepreg was sampled to a size of 20 cm x 20 cm. Eight of the obtained samples were stacked, and copper foil with a thickness of 12 μm was placed on the top and bottom layers. Then, the samples were heated at 200°C and 40 kg / cm. 2 The mixture was heated and pressed at room temperature for 120 minutes to prepare a resin substrate.

[0155] [Example of manufacturing epoxy resin substrate] The obtained prepreg was sampled to a size of 20 cm x 20 cm. Eight of the obtained samples were stacked, and copper foil with a thickness of 12 μm was further stacked on the top and bottom layers. Then, the samples were heated at 195°C and 40 kg / cm. 2 The mixture was heated and pressed at room temperature for 120 minutes to prepare a resin substrate.

[0156] [Solder heat resistance] The top and bottom copper foils were removed from the resin substrate to obtain a laminate. The resulting laminate was cut into a total of 10 pieces measuring 5 cm x 5 cm. The pieces were then heated in a pressure cooker at 133°C for 24 hours and allowed to absorb water. The water-absorbed laminate was then immersed in a solder bath at 288°C for 20 seconds, and each of the 10 laminate samples was visually inspected for blistering due to peeling at the glass cloth / resin interface.

[0157] The laminated plate samples that showed blistering due to peeling at the glass cloth / resin interface were rated as "failed," and the number of "failed" laminated plate samples was recorded. The fewer the number of glass cloths listed in the table, the more excellent the heat resistance.

[0158] The manufacturing conditions and evaluation results for the Examples and Comparative Examples are shown in the table below. Note that, using the glass cloth of the Examples, prepregs, printed wiring boards (resin substrates), integrated circuits, and electronic devices could be manufactured by conventional methods.

[0159] [Table 1]

[0160] [Table 2]

[0161] Examples 1 to 14 provided glass cloths that could achieve excellent dielectric properties, suppress an increase in the dielectric loss tangent over time, and enable a resin substrate made using the glass cloth to achieve excellent soldering heat resistance. On the other hand, Comparative Examples 1 and 2 could not suppress an increase in the dielectric loss tangent over time. [Industrial Applicability]

[0162] The present invention can be used in fields related to glass cloth, printed wiring boards (particularly printed wiring boards for high-speed communication), and the like. [Explanation of symbols]

[0163] P: White spot

Claims

1. A glass cloth configured with glass yarns containing a plurality of glass filaments as warp yarns and weft yarns, the glass cloth has a surface treatment agent on its surface; The surface treatment agent is represented by the following formula (A): 1.10×MaxEStateIndex+14.6×MaxPartialCharge−0.0917×SPS+2.47×HallKierAlpha...(A) The silane coupling agent has a molecular structure in which the value determined by The ignition loss value of the glass cloth is in the range of 0.01 to 0.3 mass%, The glass cloth has a basis weight of 8 to 250 g / m 2 .

2. 10 white spots / m ２ The glass cloth according to claim 1, wherein:

3. The silicon (Si) content in the glass fiber is silicon dioxide (SiO ２ 3. The glass cloth according to claim 1, wherein the total mass of the glass fiber is 95.0 to 100 mass % in terms of the total mass of the glass fiber.

4. The silane coupling agent is represented by the following general formula (1): X ４－ｎ -Si-Y ｎ ・・・(1) (In formula (1), each X is independently an organic functional group having at least one selected from an epoxy group, an amino group, and an unsaturated double bond group having radical reactivity; each Y is independently an alkoxy group; and n is an integer of 1 or more and 3 or less.) The glass cloth according to claim 1 or 2, which contains a silane coupling agent represented by the formula:

5. 5. The glass cloth according to claim 4, wherein X in the general formula (1) contains at least one group selected from the group consisting of an epoxy group, an amino group, an aromatic vinyl group, an acryloyl group, and a methacryloyl group.

6. 3. The glass cloth according to claim 1, wherein the dielectric loss tangent of the glass cloth at 10 GHz is 0.002 or less.

7. 3. The glass cloth according to claim 1, wherein the value determined by the formula (A) is 14.4 or less.

8. 3. The glass cloth according to claim 1, wherein the value determined by the formula (A) is 13.8 or less.

9. 3. The glass cloth according to claim 1, wherein the value determined by the formula (A) is 13.5 or less.

10. 4 white spots / m ２ The glass cloth according to claim 1 or 2, wherein:

11. 2 white spots / m ２ The glass cloth according to claim 1 or 2, wherein:

12. White spots 0.1 / m ２ The glass cloth according to claim 1 or 2, wherein:

13. White spots 0.05 / m ２ The glass cloth according to claim 1 or 2, wherein:

14. 3. The glass cloth according to claim 1, wherein the molecular weight of the silane coupling agent is in the range of 250 to 1,000.

15. 3. The glass cloth according to claim 1, wherein the molecular weight of the silane coupling agent is in the range of 300 to 750.

16. 3. The glass cloth according to claim 1, wherein the molecular weight of the silane coupling agent is in the range of 350 to 700.

17. The glass cloth according to claim 1 or 2, which is for use in a printed wiring board.

18. A prepreg comprising the glass cloth according to claim 1 or 2, a matrix resin, and an inorganic filler.

19. A printed wiring board comprising the prepreg of claim 18.

20. 20. An integrated circuit comprising the printed wiring board of claim 19.

21. An electronic device comprising the printed wiring board according to claim 19.

22. 1. A method for producing glass cloth, the method comprising: a step of weaving glass yarns containing a plurality of glass filaments as warp yarns and weft yarns to obtain a glass cloth; The method includes a step of degreasing the glass cloth and then surface-treating the glass cloth with a surface treatment liquid containing a surface treatment agent, The surface treatment agent is represented by the following formula (A): 1.10×MaxEStateIndex+14.6×MaxPartialCharge−0.0917×SPS+2.47×HallKierAlpha...(A) The silane coupling agent has a molecular structure in which the value obtained by The ignition loss value of the glass cloth is in the range of 0.01 to 0.3 mass%, The method for producing a glass cloth, wherein the glass cloth has a basis weight of 8 to 250 g / m 2 .

23. The silane coupling agent is represented by the following general formula (1): X ４－ｎ -Si-Y ｎ ・・・(1) (In formula (1), each X is independently an organic functional group having at least one selected from an epoxy group, an amino group, and an unsaturated double bond group having radical reactivity; each Y is independently an alkoxy group; and n is an integer of 1 or more and 3 or less.) The method for producing glass cloth according to claim 22, comprising:

24. The method for producing glass cloth according to claim 22 or 23, wherein the surface treatment liquid is prepared by adding an acidic aqueous solution to a hydrolysis solution of the silane coupling agent.

25. The surface treatment step includes: controlling the temperature and pH of the surface treatment solution; The method for producing glass cloth according to claim 22 or 23, further comprising filtering the surface treatment liquid.

26. The method for producing a glass cloth according to claim 22 or 23, further comprising a step of subjecting the glass cloth to an opening treatment after the surface treatment step.

27. The method for producing glass cloth according to claim 22 or 23, further comprising the step of inspecting for white spots after the surface treatment step.

28. A surface treatment liquid for glass cloth containing a surface treatment agent containing a silane coupling agent, The silane coupling agent is represented by the following formula (A): 1.10×MaxEStateIndex+14.6×MaxPartialCharge−0.0917×SPS+2.47×HallKierAlpha...(A) The surface treatment solution has a molecular structure in which the value determined by the following formula is 15.0 or less.

29. the surface treatment liquid contains the silane coupling agent in an amount of 0.20 to 1.2 mass % based on the total mass of the surface treatment liquid; the pH of the surface treatment liquid is in the range of 2.5 to 5.5; The surface treatment liquid according to claim 28, wherein the surface treatment liquid contains a surfactant in an amount of 0.5 to 5.0 mass % based on the total mass of the silane coupling agent.

30. The silane coupling agent is represented by the following general formula (1): X ４－ｎ -Si-Y ｎ ・・・(1) (In formula (1), each X is independently an organic functional group having at least one selected from an epoxy group, an amino group, and an unsaturated double bond group having radical reactivity; each Y is independently an alkoxy group; and n is an integer of 1 or more and 3 or less.) The surface treatment solution according to claim 28 or 29, comprising:

31. 30. The surface treatment solution according to claim 28 or 29, wherein the value obtained from the formula (A) is 14.4 or less.

32. 30. The surface treatment solution according to claim 28, wherein the value obtained from the formula (A) is 13.8 or less.

33. 30. The surface treatment solution according to claim 28 or 29, wherein the value obtained from the formula (A) is 13.5 or less.

34. 30. The surface treatment liquid according to claim 28, wherein the pH of the surface treatment liquid is in the range of 3.0 to 5.

0.

35. 30. The surface treatment liquid according to claim 28, wherein the pH of the surface treatment liquid is in the range of 3.0 to 4.

0.

36. 30. The surface treatment liquid according to claim 28, wherein the surface treatment liquid contains a surfactant in an amount of 1.0 to 4.5 mass % based on the total mass of the silane coupling agent.

37. 30. The surface treatment liquid according to claim 28, wherein the surface treatment liquid contains a surfactant in an amount of 1.5 to 4.0 mass % based on the total mass of the silane coupling agent.

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