Glass cloth, prepreg, and printed wiring board

Abstract

The glass cloth of the present disclosure is a glass cloth made by weaving glass yarns, the glass cloth is surface-treated with a surface treatment agent, the difference between the dielectric loss tangent of the glass cloth at 10 GHz and the bulk dielectric loss tangent of the glass constituting the glass yarn at 10 GHz (the dielectric loss tangent - the bulk dielectric loss tangent) is less than 0.00000; The number of white spots P on the glass cloth is 10 / m 2 The following is the result.

Description

[Technical Field]

[0001] The present disclosure relates to glass cloth, prepregs, printed wiring boards, 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 describe a method of 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 to obtain a prepreg. A laminate is known that is produced by laminating the prepregs obtained in this manner and curing them by heating and applying pressure. Patent Documents 1 and 2 aim to achieve a low dielectric constant and low dielectric dissipation factor for the laminate by combining the prepreg with a glass cloth that has a low dielectric constant and low dielectric dissipation factor.

[0004] In order to reduce the dielectric loss tangent of glass cloth, Patent Documents 3 and 4 report that the amount of silanol groups on the glass surface is reduced by heating silica glass cloth at high temperatures. Patent Document 5 reports that the silanol groups present on the glass cloth surface are reduced by surface treatment, thereby reducing the dielectric loss tangent of the glass cloth. Patent Document 6 reports a method of 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] However, compared to the conventional techniques described in Patent Documents 1 to 6, there has been a strong demand for the development of a technique that can further reduce the dielectric loss tangent of the glass cloth. Furthermore, glass cloth is required to have not only excellent dielectric properties but also various properties of the resulting resin substrate (for example, solder heat resistance, etc.). Furthermore, there has been a strong demand for the development of a technology for suppressing the increase in dielectric tangent over time without adopting a method of packaging the quartz glass cloth in a predetermined manner, as in the conventional technology described in Patent Document 6.

[0007] The present disclosure aims to provide a glass cloth that can achieve excellent dielectric properties, suppress an increase in dielectric loss tangent over time, and achieve excellent solder heat resistance in a resin substrate produced using the glass cloth. Another object of the present disclosure is to provide a prepreg and a printed wiring board that are realized using the glass cloth, and to provide a method for producing the glass cloth. [Means for solving the problem]

[0008] One aspect of the present invention is as follows. [1] A glass cloth made by weaving glass yarn, the glass cloth is surface-treated with a surface treatment agent, the difference between the dielectric loss tangent of the glass cloth at 10 GHz and the bulk dielectric loss tangent of the glass constituting the glass yarn at 10 GHz (the dielectric loss tangent - the bulk dielectric loss tangent) is less than 0.00000; The number of white spots on the glass cloth is 10 / m 2 Below is glass cloth. [2] Item 2. The glass cloth according to item 1, wherein the silicon (Si) content in the glass yarn is 95.0 to 100 mass % in terms of silicon dioxide (SiO2). [3] 3. The glass cloth according to item 1 or 2, wherein the average degree of opening calculated from the yarn width of each of the warp yarns and the weft yarns of the glass cloth is more than 40%. [4] 4. The glass cloth according to any one of items 1 to 3, wherein the bulk dielectric loss tangent is 0.002 or less. [5] 5. The glass cloth according to any one of items 1 to 4, wherein the surface treatment agent contains a silane coupling agent. [6] Item 6. The glass cloth according to item 5, wherein the molecular weight of the silane coupling agent is 250 to 1,000. [7] Item 7. The glass cloth according to item 5 or 6, wherein the silane coupling agent contains, in its molecule, 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. [8] 8. The glass cloth according to any one of items 5 to 7, wherein the surface treatment agent contains two or more silane coupling agents having different molecular weights. [9] 9. The glass cloth according to any one of items 1 to 8, wherein the glass cloth has an ignition loss value of 0.01 to 0.5% by mass.

[10] 10. The glass cloth according to any one of items 1 to 9, which is a constituent material for a printed wiring board.

[11] A prepreg comprising the glass cloth according to any one of items 1 to 10 and a thermosetting resin.

[12] Item 12. A printed wiring board comprising the prepreg according to item 11.

[13] Item 13. An integrated circuit comprising the printed wiring board according to item 12.

[14] Item 13. An electronic device comprising the printed wiring board according to item 12.

[15] a weaving process for weaving glass yarn to obtain glass cloth; a surface treatment step of deoiling the glass filaments and then surface treating the glass filaments with a surface treatment solution, The method for producing a glass cloth, wherein the dielectric loss tangent at 10 GHz of the glass cloth after the surface treatment is lower than the dielectric loss tangent at 10 GHz of the glass cloth before the surface treatment.

[16] Item 16. The method for producing glass cloth according to Item 15, wherein the surface treatment liquid is prepared by adding an acidic aqueous solution to a silane coupling agent as a surface treatment agent.

[17] The surface treatment step includes: controlling the temperature and pH of the surface treatment solution; Item 17. The method for producing glass cloth according to Item 15 or 16, further comprising the step of filtering the surface treatment liquid.

[18] 18. The method for producing a glass cloth according to any one of items 15 to 17, further comprising a step of subjecting the glass yarns to an opening treatment after the surface treatment step.

[19] Item 19. The method for producing a glass cloth according to any one of Items 15 to 18, further comprising a step of inspecting the glass cloth for white spots after the surface treatment step. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a glass cloth that can achieve excellent dielectric properties, suppress an increase in the dielectric loss tangent over time, and achieve excellent solder heat resistance in a resin substrate produced using the glass cloth. Furthermore, according to the present disclosure, it is possible to provide a prepreg, a printed wiring board, an integrated circuit, and an electronic device that are realized using the glass cloth, and to provide a method for manufacturing the glass cloth, etc. [Brief explanation of the drawings]

[0010] [Figure 1] 5A and 5B are diagrams for explaining white spots in the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present disclosure (hereinafter referred to as "the present embodiment") will be described. However, the present invention is not limited to the present embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0012] 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.

[0013] 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.

[0014] [Glass cloth] The glass cloth of this embodiment is a glass cloth made by weaving glass yarns, for example, a glass cloth made by weaving glass yarns made of a plurality of glass filaments as warp and weft yarns.

[0015] In one aspect of this embodiment, The glass cloth is surface treated with a surface treatment agent. the difference between the dielectric loss tangent of the glass cloth at 10 GHz and the bulk dielectric loss tangent of the glass constituting the glass yarn at 10 GHz (the dielectric loss tangent - the bulk dielectric loss tangent) is less than 0.00000; 10 white spots / m 2 Less than (e.g., 10.0 pieces / m 2 (See below).

[0016] According to this embodiment, it is possible to provide a glass cloth that can achieve excellent dielectric properties, suppress an increase in the dielectric loss tangent over time, and achieve excellent solder heat resistance in a resin substrate (printed wiring board) produced using the glass cloth. The glass cloth of this embodiment is suitable as a constituent material for producing prepregs, printed wiring boards, integrated circuits, electronic devices, etc.

[0017] As a result of extensive research, the present inventors have focused on glass cloth that has been surface-treated after being heated to deoiling at high temperatures. The present inventors have found for the first time that glass cloth having a dielectric loss tangent lower than the bulk loss tangent has an extremely small amount of silanol groups on the glass surface, making it difficult for the glass cloth to adsorb moisture present in the storage environment, and therefore it is possible to suppress an increase in the dielectric loss tangent of the glass cloth over time without special packaging.

[0018] Furthermore, we have found that to obtain glass cloth having a dielectric loss tangent lower than that of the bulk of the glass, it is preferable to perform surface treatment with a surface treatment agent having relatively strong hydrophobicity. However, such surface treatment agents have extremely poor dispersibility and / or compatibility in water, and therefore tend to cause "white spots" on the surface of the glass cloth, which are defects in appearance caused by the surface treatment agent. Since white spots impair the adhesion at the interface between the glass cloth and the resin, it is preferable to provide glass cloth having excellent appearance quality and a dielectric loss tangent lower than that of the bulk.

[0019] According to a preferred aspect of the glass cloth of this embodiment, by finding a method for stably dispersing in water even a surface treatment agent (e.g., a specific silane coupling agent) that has poor dispersibility and / or compatibility in water, the appearance quality can be improved. In this case, it becomes easy to provide a glass cloth whose dielectric loss tangent is lower than that of the bulk glass, and it becomes easy to suppress an increase in the dielectric loss tangent of the glass cloth over time without special packaging. Furthermore, it becomes easy to provide a glass cloth that has excellent solder heat resistance for resin substrates.

[0020] [Dielectric loss tangent] (Dielectric tangent of glass cloth) The glass cloth of this embodiment 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, 0.0002, 0.00019, 0.00018, 0.00017, 0.00016, 0.00015, 0.00014, 0.00013, 0.00012, or 0.00011 or less. The dielectric loss tangent of the glass cloth may be greater than 0.

[0021] (Method for measuring dielectric loss tangent) The dielectric loss tangent at 10 GHz of the glass cloth of this embodiment is measured by a method using a split cylinder resonator (a method using a resonance method), specifically, by the method described in the Examples. This method allows for simpler and more accurate measurement than conventional 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 evaluation of low-loss materials. Other than the resonance method, other methods for evaluating dielectric properties 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 problem in that the operation can be cumbersome. Furthermore, when evaluating low-loss materials, the reflection transmission method is subject to the strong influence of the port matching characteristics, making it difficult to evaluate the dielectric loss tangent of the measurement sample with high accuracy. From the above, it is possible to easily and accurately measure the dielectric loss tangent of a glass cloth by using a technique that uses a resonance method, specifically, by using the technique described in the examples.

[0022] 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 measurable range of Dk=1.1 Fm -1 ~50Fm -1 , and Df = 1.0 × 10 -6 ~1.0×10 -1 It is preferable that the measurable range is Dk=1.5Fm -1 ~10Fm -1 , and Df = 1.0 × 10 -5 ~5.0×10 -1 It is more preferable that the measurable range is Dk=2.0Fm -1 ~5Fm -1 , and Df = 5.0 × 10 -5~1.0×10 -2 It is more preferable that the measurable range is .gtoreq..times ...

[0023] 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.

[0024] 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.

[0025] 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.

[0026] (Bulk dielectric loss tangent) In the glass cloth of this embodiment, 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, and glass seeds.

[0027] 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 0.0002 or less, which makes it easier to achieve the effects of the present disclosure.

[0028] (Method for controlling dielectric loss tangent of glass cloth) The dielectric loss tangent of the glass cloth is, for example, A method for removing deteriorated materials and residues present on the surface of glass fibers; and a method for surface treating a glass fiber with a surface treatment agent capable of reducing the dielectric loss tangent of the glass cloth; It can be controlled by the following. Here, one embodiment of the deteriorated product and the residue, etc., is, for example, the following (i) to (ii): (i) Degraded sizing agent physically attached to the glass surface is thermally oxidized (ii) Residues of surface treatment agents that physically adhere to the glass surface without forming a chemical bond with the surface and remain on the surface even after washing with water, or modified products thereof is.

[0029] (Difference between dielectric loss tangent and bulk dielectric loss tangent) In the glass cloth of this embodiment, the difference (the dielectric loss tangent - the bulk dielectric loss tangent) is less than 0.00000. This relationship is achieved when the bulk dielectric loss tangent is greater than the dielectric loss tangent by more than 0.00000. The methods for measuring the dielectric loss tangent and the bulk dielectric loss tangent, as well as the methods for controlling them, are as described above.

[0030] From the viewpoint of easily achieving the effects of the present disclosure, the difference (the dielectric loss tangent - the bulk dielectric loss tangent) is preferably -0.00002 or less, more preferably -0.00003 or less, even more preferably -0.00004 or less, still more preferably -0.00005 or less, even more preferably -0.00006 or less or -0.00007 or less, and particularly preferably -0.00008 or less. The dielectric loss tangent of the glass cloth may be more than -0.0002.

[0031] [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.

[0032] [Average filament diameter] The average filament diameter of the glass filaments is preferably 2.5 to 9.0 μm, more preferably 2.5 to 7.5 μm, even more preferably 3.5 to 7.0 μm, still more preferably 3.5 to 6.0 μm, and particularly preferably 3.5 to 5.0 μm.

[0033] [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 40 to 100 yarns / inch.

[0034] [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.

[0035] [Glass type] Conventionally, glass cloth used in prepregs (laminates) is usually a glass raw material called E-glass (alkali-free glass). On the other hand, for the glass cloth of this embodiment, glass raw materials such as L-glass, NE-glass, D-glass, L2-glass, T-glass, silica glass, and quartz glass may be used. 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 them, 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 them, silica glass and quartz glass are particularly preferred.

[0036] 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%. A particularly preferred embodiment of the SiO2 composition content of the glass yarns constituting the glass cloth is 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.

[0037] [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.

[0038] [Surface treatment agent (surface treatment liquid)] The surface treatment liquid may contain a surface treatment agent. In this embodiment, the surface treatment is performed, for example, by a method using a surface treatment liquid.

[0039] Conventionally, it has been recognized that when a general surface treatment agent (for example, a general silane coupling agent) is used, the dielectric loss tangent of the glass cloth increases due to the surface treatment. As a result of investigations into this point, 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), moisture present in the storage environment becomes less likely to be adsorbed onto the glass surface, and as a result, it becomes easier to suppress the increase in the dielectric tangent of the glass cloth over time, even without a special packaging form.

[0040] In the present disclosure, a "strongly hydrophobic surface treatment agent (strongly hydrophobic silane coupling agent)" is defined as an agent in which, when an aqueous solution prepared by mixing a 0.3% by mass aqueous solution of acetic acid with a surface treatment agent (silane coupling agent) at a concentration of 0.8% by mass is stirred for 3 hours at room temperature of 25°C, the surface treatment agent (silane coupling agent) is not dissolved or uniformly dispersed in the aqueous solution, for example, the surface treatment agent (silane coupling agent) is separated in the aqueous solution as oil droplets and an oil film.

[0041] (molecular weight) The molecular weight of the surface treatment agent, for example, the molecular weight of the silane coupling agent, is preferably 250 to 1,000, more preferably 270 to 800, still more preferably 300 to 750, and particularly preferably 350 to 700. When two or more surface treatment agents (e.g., silane coupling agents) are used, it is preferable that the weighted average value of the molecular weights of the surface treatment agents, where the weight is the mass of each surface treatment agent, is within the above range, and it is more preferable that the molecular weights of all of the multiple surface treatment agents used are within the above range. For example, when a surface treatment agent is formulated so that silane coupling agents having molecular weights of 300 and 500 are present at 0.5 mass % and 1.0 mass %, the weighted average value is calculated by the following formula: Weighted average value = {(300 x 0.5) / (0.5 + 1.0)} + {(500 x 1.0) / (0.5 + 1.0)} = 433 It is calculated as follows:

[0042] (Silane coupling agent) In this embodiment, the surface treatment agent preferably contains a silane coupling agent. That is, the glass threads (including glass filaments) constituting the glass cloth are preferably surface-treated with a silane coupling agent.

[0043] The surface treatment agent is, for example, a compound represented by the following formula (1): X 3-n SiY n ···(1) (In the formula, each X is independent and may contain a different organic functional group, and is composed of a functional group having a total of two or more carbonyl groups and two or more unsaturated carbon-carbon double bonds; each Y is independently an alkoxy group; and n is an integer of 1 or more and 3 or less.) This makes it possible to make the difference between the dielectric loss tangent of the glass cloth and the dielectric loss tangent of the glass bulk (the above-mentioned dielectric loss tangent - the above-mentioned bulk dielectric loss tangent) less than 0.00000, and further makes it easier to suppress an increase in the dielectric loss tangent of the glass cloth over time.

[0044] The silane coupling agent preferably contains at least one group selected from the group consisting of an epoxy group, an amino group, an acryloyl group, and a methacryloyl group in its molecule. For example, from the viewpoint of easily improving adhesion to resin, it is preferable that X 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.

[0045] 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.

[0046] 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.

[0047] Examples of the silane coupling agent represented by the general formula (1) include: 4-(Trimethoxysilyl)phenyl 2-methyl-2-propenoate, 1-[2-(Trimethoxysilyl)ethyl]pentyl 2-methyl-2-propenoate, [4-[2-(Trimethoxysilyl)ethyl]phenyl]methyl 2-propenoate, N-2-Propen-1-yl-N-[3-(trimethoxysilyl)propyl]-2-oxiranemethamine, 3-(Ethenyloxy)-2-[(trimethoxysilyl)oxy]propyl 2-propenoate, 6-[[[3-(Trimethoxysilyl)propyl]amino]carbonyl]-2-naphthalenyl 2-methyl-2-propenoate, 3-[2-(Trimethoxysilyl)ethyl]tricyclo[3.3.1.1 3,7 ]dec-1-yl 2-methyl-2-propenoate, 4′-[(4-Methylphenyl)[4-[2-(trimethoxysilyl)ethyl]phenyl]amino][1,1′-biphenyl]-4-yl 2-methyl-2-propenoate, Silane, trimethoxy[3-(7-oxabicyclo[4.1.0]hept-3-ylmethoxy)propyl], 1,3-Bis(2-oxiranylmethyl)-5-[3-(trimethoxysilyl)propyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, N 1 -[10-(Trimethoxysilyl)decyl]-1,3-benzenedimethanamine, etc.

[0048] The silane coupling agent that can be used can be appropriately adjusted depending on the dielectric loss tangent of the glass cloth before surface treatment, the matrix resin used in the resin substrate, etc. Of course, the silane coupling agent represented by the above formula (1) may be used in combination with a silane coupling agent other than that represented by the above formula (1). On the other hand, it is preferable to use two or more silane coupling agents represented by the above formula (1) that have different molecular weights. By using two or more silane coupling agents that have different molecular weights, the density of the treatment agent on the glass surface tends to increase, and as a result, the reactivity with the matrix resin tends to be further improved.

[0049] [Average opening degree of glass cloth] The average degree of opening of the glass cloth is preferably 38% or more or more than 40%, more preferably more than 43%, even more preferably more than 46%, more than 50%, more than 53%, more than 56%, or more than 60%, and particularly preferably more than 65%. When the average degree of opening of the glass cloth is 38% or more, it is easy to prevent air bubbles called voids from remaining in the bundle of glass yarns when a resin substrate is produced, and as a result, it is less likely to have an adverse effect on solder heat resistance, insulation reliability, etc. The silane coupling agent represented by the formula (1) tends to exert relatively strong intermolecular forces, and therefore tends to be less effective in impregnating the glass cloth with the matrix resin than silane coupling agents other than those represented by the formula (1). Therefore, in order to fully obtain the effect of improving the insulation reliability of glass cloth surface-treated with the silane coupling agent represented by the formula (1), it is preferable that the average degree of opening is 38% or more, or exceeds 40%.

[0050] [Ignition loss value of glass cloth] From the viewpoint of easily reducing the dielectric loss tangent of the glass cloth, the ignition loss value of the glass cloth is preferably 0.01 to 0.5 mass%, or 0.01 to 0.4 mass%, or 0.01 to 0.3 mass%, more preferably 0.02 to 0.25 mass%, even more preferably 0.03 to 0.22 mass%, even more preferably 0.03 to 0.17 mass%, and particularly preferably 0.04 to 0.15 mass%. When the ignition loss value is 0.01 mass% or more, adhesion between the resin and the glass cloth in the obtained prepreg is easily ensured. In this case, when a printed wiring board is produced, heat resistance and insulation reliability are easily ensured. When the ignition loss value of the glass cloth is 0.5% by mass or less, it is easy to avoid a situation in which a surface treatment agent (or its residue) that is physically attached to the glass cloth surface without forming a chemical bond with the glass cloth surface, a surface treatment agent (or its residue) that cannot be removed from the glass cloth surface by washing with water, and / or modified products thereof are present in large amounts on the glass cloth surface, which makes it easy to achieve a low dielectric loss tangent of the glass cloth.

[0051] [White spots on glass cloth] White stains (white spots) may be observed on the surface of the surface-treated glass cloth. These white spots tend to repel the matrix resin used in the preparation of the prepreg, which may result in poor appearance of the resulting prepreg. It has been previously believed that the cause of these white spots is unknown.

[0052] In this regard, the present inventors have clarified that one of the white spots is an aggregate of a highly hydrophobic surface treatment agent (for example, a highly hydrophobic silane coupling agent) or a modified product thereof. In particular, the present inventors have found that the silane coupling agent represented by the above formula (1) 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 The above was made clear.

[0053] To suppress white spots, as described below, Mixing the surface treatment solution by a predetermined method; Temperature and pH control of the surface treatment solution, and filtering the surface treatment liquid to remove aggregates in the surface treatment liquid; Techniques such as those described above are suitable.

[0054] The frequency of white spots on glass cloth is 7.0 / m 2 Preferably less than 4.0 pieces / m 2 Less than 2.0 pieces / m is more preferable. 2 Less than or equal to 0.1 pieces / m 2 More preferably, 0.05 particles / m or less 2 The following is particularly preferable. This makes it easy to realize a prepreg with excellent appearance. The frequency of white spots occurring in the glass cloth is 0 / m. 2 Exceeding is fine.

[0055] [Glass cloth manufacturing method] One aspect of this embodiment is a manufacturing method for manufacturing the glass cloth of this embodiment. The manufacturing method of this embodiment is as follows: a weaving process for weaving glass yarn to obtain glass cloth; a surface treatment step of deoiling the glass filaments and then surface treating the glass filaments with a surface treatment solution, The dielectric loss tangent at 10 GHz of the glass cloth after the surface treatment is lower than the dielectric loss tangent at 10 GHz of the glass cloth before the surface treatment.

[0056] Here, the manufacturing method of this embodiment may optionally include 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 process of washing the glass yarn with water (finish washing process), and / or The process of opening glass threads (opening process).

[0057] At least one of the surface treatment step, the opening step, and the finish washing 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 finish washing step may be reversed. When the washing step is performed after the weaving step, the washing 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 opening.

[0058] [Heat deoiling process] In this step, by heating the glass yarn, it is possible to reduce, and preferably remove, any fiber sizing agent (sizing agent) and its residues, as well as modified products thereof, that are attached to the glass yarn. By performing the thermal deoiling step, 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, and therefore it is easy to produce glass cloth with excellent dielectric properties. As a means for thermal deoiling, known means (heating means, heating medium, heating mechanism, heating device, heating component, etc.) can be used.

[0059] One embodiment of the thermal deoiling step is, for example, A method of heating glass cloth at a temperature of 600 to 1600°C. etc. are known.

[0060] In the heat treatment step, by heating the glass cloth greige, whose glass yarn has a 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, the effects of the present disclosure can be easily achieved.

[0061] From the viewpoint of suitably obtaining the effects of the present disclosure, 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] To obtain the effects of the present disclosure, 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 the surface treatment step, the glass filaments are treated with a surface treatment solution containing a surface treatment agent having a molecular weight of 200 or more. 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.

[0074] In the method of this embodiment, in the surface treatment step, the glass fiber is surface-treated using 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 this embodiment is more hydrophobic than general silane coupling agents. As described above, the present inventors have revealed that when the solvent in the surface treatment liquid contains water, aggregates of the surface treatment agent tend to be easily generated, and that when the solvent in the surface treatment liquid contains water, the frequency of occurrence of white spots on the glass cloth after surface treatment tends to increase.

[0075] The present inventors have found that in a given surface treatment liquid, it is possible to suppress white spots on glass cloth by taking the following measures (A) to (C), for example. (A) Adding a solvent (for example, a weakly acidic aqueous solution as a mother liquor) to the surface treatment agent; (B) controlling the temperature and / or pH of the surface treatment solution during the surface treatment; (C) Filtering the surface treatment solution during surface treatment.

[0076] (A) Preparation of surface treatment solution Since typical silane coupling agents have excellent compatibility with and dispersibility in water, they are prepared by adding the silane coupling agent in small amounts to weakly acidic water with a pH of about 3 to 5 while stirring. On the other hand, in the method of this embodiment, a pre-solution of the surface treatment agent can be obtained by adding a surfactant and a small amount of solvent for hydrolyzing the silane coupling agent (for example, a 60% aqueous acetic acid solution) to a diluted solution obtained by diluting the surface treatment agent with a small amount of methanol. The solvent added to 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, an aqueous solution adjusted to a pH of 3 to 4 (also referred to as the "mother liquor" in the present disclosure) is added little by little 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 agglomerations in the surface treatment solution. To easily suppress white spots, the content of the silane coupling agent in the surface treatment solution is preferably in the range of 0.01 to 2.0 mass%, more preferably 0.01 to 1.8 mass%, even more preferably 0.02 to 1.5 mass%, even more preferably 0.02 to 1.3 mass%, and particularly preferably 0.02 to 1.0 mass%. If the content of the silane coupling agent exceeds 2.0 mass%, the amount of silane coupling agent attached to the glass cloth becomes too large, which tends to increase the dielectric loss tangent of the glass cloth. Furthermore, the relatively large number of silanol groups not bonded to the glass cloth makes it more likely to adsorb moisture from the air, which in turn tends to cause the dielectric loss tangent of the glass cloth to increase over time. On the other hand, if the content of the silane coupling agent is less than 0.01 mass%, the amount of silane coupling agent attached to the glass cloth is too small, which makes it difficult for the silane coupling agent to react with the matrix resin, thereby adversely affecting the solder heat resistance of the substrate.

[0077] 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.

[0078] The amount of the surfactant is preferably 0.2 to 10 mass % relative to the surface treatment agent (for example, silane coupling agent), more preferably 0.4 to 9 mass %, even more preferably 0.6 to 8 mass %, and particularly preferably 1 to 6 mass %. When the amount of the surfactant satisfies the above range, it becomes easier to uniformly disperse the silane coupling agent.

[0079] 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.

[0080] 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.

[0081] Examples of cationic surfactants include monoalkylamine salts, dialkylamine salts, trialkylamine salts, alkyltrimethylammonium chloride, and alkylbenzalkonium chloride.

[0082] Examples of amphoteric surfactants include 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, alkyl betaine, fatty acid amidopropyl betaine, alkyldiethylenetriaminoacetic acid, and alkylamine oxide.

[0083] (B) Temperature control and / or pH control of the surface treatment solution From the viewpoint of suppressing aggregation in the surface treatment liquid, the temperature of the surface treatment liquid is preferably controlled at 10 to 30°C, more preferably at 13 to 27°C, even more preferably at 15 to 25°C, and particularly preferably at 17 to 23°C during the surface treatment.

[0084] Furthermore, during the surface treatment, impurities such as alkali metals contained in trace amounts in the glass cloth may cause the pH of the surface treatment solution to fluctuate. From the viewpoint of suppressing agglomeration in the surface treatment solution, it is preferable to minimize the pH fluctuation range of the surface treatment solution. During the surface treatment, the pH of the surface treatment solution is preferably controlled to be between 2.5 and 5.5, more preferably between 2.8 and 5.2, and even more preferably between 3.0 and 5.0. Examples of methods for controlling the pH within a predetermined range include bubbling carbon dioxide into the surface treatment solution.

[0085] 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.

[0086] Here, "temperature control of the surface treatment liquid" is a concept that includes not only an operation of increasing and / or decreasing 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 of the surface treatment liquid to confirm whether the temperature is within a predetermined range. Furthermore, the concept of "pH control of the surface treatment solution" includes not only an operation for increasing and / or decreasing the pH of the surface treatment solution, but also an operation for maintaining the pH of the surface treatment solution at a predetermined value, and an operation for detecting the pH of the surface treatment solution to determine whether the pH is within a predetermined range.

[0087] (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.

[0088] 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.

[0089] (drying process) The surface treatment process is a step of applying a surface treatment liquid to the glass fiber and then drying the solvent contained in the surface treatment liquid (drying step); It may further include: The drying step makes it easy to fix the surface treatment agent to the surface of the glass yarn (surface of the glass filaments), and in particular makes it easy to fix the surface treatment agent to the surface of each individual glass yarn (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.

[0090] 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.

[0091] [Opening process] The manufacturing method of this embodiment preferably includes a fiber-opening step after the surface treatment step. Examples of the spreading method in the spreading step include spreading the glass cloth with spray water (high-pressure water spreading), a vibro washer, ultrasonic water, a mangle, or the like. By reducing the tension applied to the glass cloth during this spreading 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 spreading 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.

[0092] [Cleaning process] The washing step (finish washing step) is preferably a method capable of reducing the residue of the surface treatment agent that has not formed a chemical bond with 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 easy to adjust the difference between the dielectric loss tangent and bulk dielectric loss tangent of the obtained glass cloth to within a predetermined range.

[0093] 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 the washing method include known methods such as immersion and shower spraying, and washing may be performed while heating or cooling as necessary. In order to prevent the dissolved deposits from re-adhering to the glass cloth, it is preferable to reduce the excess solvent from the washed glass cloth using a squeeze roller or the like before finish 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; Halogen-containing solvents such as chloroform, dichloromethane, and dichloroethane; etc.

[0094] Examples of organic solvents that have a high affinity with modified surface treatment agents (e.g., silane coupling agents) include: Alcohols such as methanol, ethanol, butanol, etc.; 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; etc.

[0095] 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.

[0096] The manufacturing method of this embodiment 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 less. Known methods such as heat drying and air drying can be used to dry the organic solvent.

[0097] 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.

[0098] [Optional step] The manufacturing method of this embodiment may optionally include other steps in addition to the steps described above. Other steps include, for example, a step of processing the glass cloth into slits (slit processing step).

[0099] (Inspection process or measurement process) In addition, other processes include: inspecting the glass cloth for white spots; The manufacturing method of this embodiment includes these steps, which makes it easy to realize the glass cloth of this embodiment.

[0100] [Prepreg] The prepreg of this embodiment contains glass cloth, a matrix resin, and an inorganic filler. The prepreg of this embodiment can be made by using the glass cloth of this embodiment as the glass cloth. This provides a prepreg with excellent properties (for example, a prepreg with few voids).

[0101] 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.

[0102] 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:

[0103] 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.

[0104] 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.

[0105] [Printed wiring board] The printed wiring board of this embodiment includes a prepreg. In particular, the printed wiring board of this embodiment includes the prepreg of this embodiment as the prepreg. This can provide a printed wiring board with excellent properties (for example, a printed wiring board with excellent insulation reliability).

[0106] [Integrated circuits and electronic devices] The integrated circuit of this embodiment includes the printed wiring board of this embodiment. Also, the electronic device of this embodiment includes the printed wiring board of this embodiment. These provide an integrated circuit and electronic device with various excellent characteristics. [Example]

[0107] The present embodiment will be described below with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples. Regarding the examples and comparative examples, various productions, measurements, evaluations, etc. were carried out by the following methods.

[0108] [Thickness] In accordance with 7.10 of JIS R 3420, a micrometer was used to gently rotate the spindle, bringing it into light contact parallel to the measurement surface, and the scale was read 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.

[0109] [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.

[0110] [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.

[0111] [Dielectric loss tangent] The dielectric loss tangent of each glass cloth was measured in accordance with IEC 62562. Specifically, glass cloth samples were sampled 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 were then measured at 10 GHz 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 thickness of each sample was calculated using the equivalent thickness. 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.

[0112] [Bulk dielectric loss tangent] A 300 μm thick glass plate having the same type and composition as each glass cloth for which the dielectric loss tangent was measured was prepared. The thickness obtained from the thickness measurement of the glass plate was used to measure the bulk dielectric loss tangent at 10 GHz in the same manner as in the measurement of the dielectric loss tangent.

[0113] [Difference in dielectric loss tangent (above dielectric loss tangent - above bulk dielectric loss tangent)] Based on the dielectric loss tangent and the bulk dielectric loss tangent obtained by the above measurement method, the difference between the dielectric loss tangents (the dielectric loss tangent - the bulk dielectric loss tangent) was determined.

[0114] [Increase in dielectric 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 for one week in a high-temperature, high-humidity environment (40°C, relative humidity 90%), and the increase in the dielectric loss tangent over time 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]

[0115] [Ignition loss value] The ignition loss value of the glass loss 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 calculated using the following formula, rounded to the fourth decimal place, and expressed to three decimal places. Ignition loss (%) = (A (mg) - B (mg))) / A (mg) x 100

[0116] [Average filament diameter of glass yarn] The cross sections of 30 glass filament bundles at arbitrary positions on the glass filaments were observed under a scanning electron microscope, and the average value was calculated to determine the average filament diameter.

[0117] [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:

[0118] 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.

[0119] (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, image acquisition of the glass yarn and 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 (or weft).

[0120] (Warp width and weft width) In calculating the average degree of opening, the warp width and the weft width were determined by the following method. First, five glass cloth test pieces each measuring 70 mm in the warp direction and 70 mm in the weft direction were cut out from the glass cloth. Each cut specimen was observed vertically using a macroscope at 100x magnification. For each specimen, the widths of 250 warp (or weft) yarns were randomly measured, and the average value of the widths of the 250 warp (or weft) yarns was calculated. The calculated average value was used as the warp width (or weft width).

[0121] [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.

[0122] [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.

[0123] [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.

[0124] [Preparation of surface treatment solution] The surface treatment liquid was prepared according to the following methods 1) to 5). 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 was mixed with 0.8% by mass of polyoxyethylene alkyl ether relative to the silane coupling agent and stirred. After stirring for 1 minute, an aqueous solution of acetic acid (concentration: 60% by mass) at 20% by mass relative to the silane coupling agent was added to the silane coupling agent solution. This hydrolyzed the silane coupling agent. 4) A mother liquor of an aqueous acetic acid solution (pH = 3 to 4) was prepared. The silane coupling agent solution (pre-solution) obtained in 3) above was stirred for 15 minutes at room temperature of 20 to 25°C. The mother liquor was then added dropwise to the stirred silane coupling agent solution, thereby dispersing the silane coupling agent. The amount of mother liquor added (dropping rate) was set so that the entire amount of mother liquor was added in 10 minutes. 5) After step 4), the silane coupling agent solution was stirred at room temperature of 20 to 25° C. for 2 hours to obtain a surface treatment liquid.

[0125] In one embodiment, the "solvent" in the "step of preparing a surface treatment liquid by adding a solvent to a surface treatment agent" of the present disclosure is the mother liquid. Here, an example of the mother liquid is a weakly acidic aqueous solution with a pH of 3 to 4, which is added for the purpose of dispersing the silane coupling agent after hydrolysis.

[0126] [Examples and Comparative Examples] Example 1 The glass cloth P was washed with ion-exchanged water and then dried. This removed alkali metal ions and the like adhering to the surface of the glass cloth. Thereafter, the glass cloth was heated and deoiled for 5 minutes while being conveyed in a furnace adjusted to a set temperature of 1000°C (thermal deoiling step). The furnace was adjusted to a nitrogen atmosphere during the thermal deoiling.

[0127] The surface treatment liquid was prepared by the above method using 4-(Trimethoxysilyl)phenyl 2-methyl-2-propenoate (CAS NO: 2097368-37-9, molecular weight = 282.36, silane coupling agent A) as the silane coupling agent so that the concentration of the silane coupling agent in the surface treatment liquid was 0.4 mass%.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] After surface treatment, the spray nozzle was used to spray 3.0 kg / cm onto the glass cloth. 2 Then, in water, the fiber was opened at a frequency of 25 kHz and an output of 0.50 W / cm. 2 The 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.

[0132] 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) was used as the silane coupling agent.

[0133] Example 3 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that 6-[[[3-(Trimethoxysilyl)propyl]amino]carbonyl]-2-naphthalenyl 2-methyl-2-propenoate (CAS NO: 1537868-42-0, molecular weight = 417.53, silane coupling agent C) was used as the silane coupling agent.

[0134] Example 4 A 2000 m glass cloth was obtained in the same manner as in Example 1, except that 1,3-Bis(2-oxiranylmethyl)-5-[3-(trimethoxysilyl)propyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (CAS NO: 1331829-87-8, molecular weight = 403.46, silane coupling agent D) was used as the silane coupling agent.

[0135] Example 5 As a silane coupling agent, N 1 A glass cloth of 2000 m was obtained in the same manner as in Example 1, except that -[10-(Trimethoxysilyl)decyl]-1,3-benzenedimethanamine (CAS NO: 149048-51-1, molecular weight = 396.64, silane coupling agent E) was used.

[0136] Example 6 A surface-treated glass cloth (2000 m) was obtained in the same manner as in Example 1, except that 4'-[(4-Methylphenyl)[4-[2-(trimethoxysilyl)ethyl]phenyl]amino][1,1'-biphenyl]-4-yl 2-methyl-2-propenoate (CAS NO: 1266672-96-1, molecular weight = 567.75, silane coupling agent F) was used as the silane coupling agent.

[0137] Example 7 A glass cloth of 2000 m was obtained in the same manner as in Example 1, except that the glass cloth Q was used instead of the glass cloth P.

[0138] Example 8 A glass cloth of 2000 m was obtained in the same manner as in Example 1, except that the glass cloth P was replaced with the glass cloth R.

[0139] Example 9 A glass cloth of 2000 m was obtained in the same manner as in Example 3, except that the surface treatment was carried out without filtering the surface treatment solution.

[0140] Example 10 The concentration of the surface treatment solution was adjusted to a total of 0.4 mass%, with 0.2 mass% of silane coupling agent A and 0.2 mass% of silane coupling agent B. Instead of using a spray nozzle to open the fibers, ultrasonic opening was performed with an output of 0.20 W / cm. 2 A glass cloth of 2000 m was obtained in the same manner as in Example 1, except that the above-mentioned step was carried out.

[0141] Example 11 A glass cloth of 2000 m was obtained in the same manner as in Example 3, 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.

[0142] (Comparative Example 1) A surface-treated glass cloth of 2000 m was obtained in the same manner as in Example 1, except that the concentration of the surface treatment solution was adjusted to 0.9 mass % and the thermal deoiling temperature was changed to 700°C.

[0143] (Comparative Example 2) A surface-treated glass cloth of 2000 m was obtained in the same manner as in Example 1, except that the concentration of the surface treatment solution was adjusted to 2.5 mass %.

[0144] (Comparative Example 3) A 2000 m glass cloth was obtained in the same manner as in Example 1, except that a surface treatment liquid was prepared by dropping a silane coupling agent solution into a mother liquor of an aqueous acetic acid solution under stirring, that the surface treatment liquid was not filtered but the surface treatment of the glass cloth was carried out, that the surface treatment liquid was not cooled even when the temperature of the surface treatment liquid exceeded 23°C, and that carbon dioxide bubbling was not carried out even when the pH exceeded 4.0.

[0145] [Frequency of white spots] The frequency of occurrence of white spots on the surface of the glass cloth was evaluated by irradiating glass cloth of A4 size (210 mm × 297 mm) or more with a halogen lamp. When observing a sheet-like glass cloth, the halogen lamp was placed directly above the glass cloth, and the number of white spots was calculated by the following formula while changing the direction of observation of the glass cloth: White spot occurrence frequency (pieces / m 2 ) = Number of white spots / {Area of ​​glass cloth (m 2 )} The frequency of occurrence of white spots was calculated according to the following. In addition, in the case of observing a glass cloth roll, a tension of 100 N / 1300 mm was applied to the glass cloth on a roll-to-roll inspection table, and the number of white spots on the glass cloth was counted over a length of 2000 m while irradiating it with a halogen lamp. Then, the inspection area and the number of white spots found in the inspection were calculated using the following formula: 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.

[0146] Figure 1 shows photographs for explaining the "white spot" in this example. Figure 1(a) shows a photograph of a location without a white spot, and Figure 1(b) shows a photograph of a location with a white spot P. In this example, a white outline was observed by irradiating the sample with UV light, and the area enclosed by the outline (the area including the outline) was 0.8 cm 2 The defects are defined as "white spots", where the contour is, for example, circular. The area enclosed by the contour line was calculated using known image analysis software.

[0147] [Prepreg manufacturing method 1] In this production method 1, a polyphenylene ether resin was used as a 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 to prepare a varnish. The glass cloths obtained in Examples 1 to 4, 6 to 11 and Comparative Examples 1 to 3 were impregnated with the prepared varnish and then dried at 130° C. for 1 minute to obtain prepregs.

[0148] [Prepreg manufacturing method 2] In this production method 2, an epoxy resin was used as a raw material. That is, 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 cloths obtained in Examples 4 and 5 were impregnated with the prepared varnish and then dried at 130° C. for 7 minutes to obtain prepregs.

[0149] [Method for producing 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. 2The mixture was heated and pressed at room temperature for 120 minutes to prepare a resin substrate.

[0150] [Method for 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.

[0151] [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.

[0152] 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.

[0153] 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.

[0154] [Table 1]

[0155] [Table 2]

[0156] According to the examples, it was possible to provide glass cloths that can realize excellent dielectric properties, suppress an increase in the dielectric loss tangent over time, and realize excellent solder heat resistance for resin substrates made using the glass cloth. On the other hand, in Comparative Examples 1 and 2, it was not possible to suppress an increase in the dielectric loss tangent over time, and in Comparative Example 3, it was not possible to obtain excellent properties regarding solder heat resistance. [Industrial Applicability]

[0157] 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]

[0158] P: White spot

Claims

1. A glass cloth made by weaving glass yarn, the glass cloth is surface-treated with a silane coupling agent that is not dissolved or uniformly dispersed in an aqueous solution when the aqueous solution is stirred for 3 hours at room temperature of 25°C, the aqueous solution being prepared by mixing a silane coupling agent with an aqueous solution of 0.3% by mass of acetic acid so that the silane coupling agent has a concentration of 0.8% by mass; The glass cloth has a difference (dielectric loss tangent - bulk dielectric loss tangent) between the dielectric loss tangent at 10 GHz of the glass cloth and the bulk dielectric loss tangent at 10 GHz of the glass constituting the glass yarns, which is less than 0.00000.

2. The silicon (Si) content in the glass fiber is silicon dioxide (SiO 2 2. 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.

3. 3. The glass cloth according to claim 1, wherein an average degree of opening calculated from the yarn widths of the warp and weft of the glass cloth is more than 40%.

4. 3. The glass cloth according to claim 1, wherein the bulk dielectric loss tangent is 0.002 or less.

5. 5. The glass cloth according to claim 4, wherein the molecular weight of the silane coupling agent is 250 to 1,000.

6. 5. The glass cloth according to claim 4, wherein the silane coupling agent contains, in its molecule, 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.

7. The glass cloth according to claim 4, wherein the silane coupling agent comprises two or more types of silane coupling agents having different molecular weights.

8. 3. The glass cloth according to claim 1, wherein the ignition loss of the glass cloth is 0.01 to 0.5 mass %.

9. The glass cloth according to claim 1 or 2, which is a constituent material of a printed wiring board.

10. A prepreg comprising the glass cloth according to claim 1 or 2 and a thermosetting resin.

11. A printed wiring board comprising the prepreg of claim 10.

12. An integrated circuit comprising the printed wiring board of claim 11.

13. An electronic device comprising the printed wiring board according to claim 11.

14. a weaving process for weaving glass yarn to obtain glass cloth; and a surface treatment step of degreasing the glass filaments and then surface treating the glass filaments with a surface treatment solution prepared by adding an acidic aqueous solution to a silane coupling agent as a surface treatment agent, The method for producing a glass cloth, wherein the dielectric loss tangent at 10 GHz of the glass cloth after the surface treatment is lower than the dielectric loss tangent at 10 GHz of the glass cloth before the surface treatment.

15. The surface treatment step includes: controlling the temperature and pH of the surface treatment solution; The method for producing glass cloth according to claim 14, further comprising the step of filtering the surface treatment liquid.

16. The method for producing glass cloth according to claim 14, further comprising a step of subjecting the glass yarns to an opening treatment after the surface treatment step.

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