Glass cloth, prepreg, and print circuit board

Abstract

To provide a glass cloth capable of realizing a prepreg and a print circuit board excellent in dimensional stability, and suppressing generation of pinholes in the prepreg.SOLUTION: A glass cloth contains a glass yarn as a warp and a weft. Weaving densities of the warp and the weft are 50 to 110 yarns / 25 mm, a thickness of the glass cloth is 20 μm or less, and an average gap intervals in a weft direction and a warp direction forming a basket hole are 162 to 240 μm and 65 to 200 μm, respectively.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a glass cloth, a prepreg, a printed wiring board, and the like. [Background technology]

[0002] In recent years, with the miniaturization of electronic devices, there has been a strong demand for lighter printed wiring boards. To reduce the mass of materials used in printed wiring boards, there is also a demand for a lighter mass of the glass cloth contained in prepreg.

[0003] Patent Documents 1 to 4 report methods for producing prepregs using low-mass glass cloth. Each of Patent Documents 1 to 4 attempts to suppress the occurrence of pinholes in the prepreg by controlling the degree of opening of the glass cloth or the gap spacing of the yarn width. Patent Document 5 reports a method for producing a printed wiring board using a low-mass glass cloth. Patent Document 6 reports a method for producing a printed wiring board using a low-mass glass cloth, and attempts to improve the dimensional stability and mechanical properties of the printed wiring board by controlling a value known as the "surface glass yarn coverage rate." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-075805 [Patent Document 2] Japanese Patent Application Publication No. 2017-043873 [Patent Document 3] Japanese Patent Application Publication No. 2018-021274 [Patent Document 4] WO2019 / 163159 publication [Patent Document 5] WO2015 / 033731 publication [Patent Document 6] Japanese Patent Application Laid-Open No. 2005-213656 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, with the trend toward high performance, small size, and light weight digital devices, there has been a demand for printed wiring boards to be further miniaturized and thinned, and for finer and higher density wiring. Therefore, glass cloths and prepregs used in the above-mentioned applications, such as printed wiring board applications, are also required to be thinner and have better dimensional stability.

[0006] In order to make glass cloth and prepreg thinner, it is generally advantageous to use glass yarns with a small TEX value (mass per 1000 m of glass yarn) and to weave the glass yarns at a high weaving density.

[0007] In the glass cloth, gaps surrounded by the warp and weft yarns are called "basket holes." In some cases, defects called "pinholes" occur in the prepreg due to the basket holes not being sufficiently filled with thermosetting resin. It is known that controlling the weaving density to a high density can easily suppress the occurrence of defects (pinholes) in the prepreg, and also provides the advantage of making the glass cloth less likely to wrinkle during transport.

[0008] However, the present inventors have found that controlling the weave density to a high density makes it more likely that there will be a difference in the amount of thermosetting resin between the front and back of the prepreg, which in turn reduces the dimensional stability of both the prepreg and the resulting printed wiring board.

[0009] Therefore, an object of the present invention is to provide a glass cloth that can realize a prepreg and a printed wiring board having excellent dimensional stability and can suppress the occurrence of pinholes in the prepreg. Another object of the present invention is to provide prepregs, printed wiring boards, and the like obtained by using such glass cloth. [Means for solving the problem]

[0010] One aspect of the present invention is as follows. [1] A glass cloth containing glass yarns as warp and weft yarns, The weaving density of the warp yarns and the weft yarns is 50 to 110 yarns / 25 mm, The thickness of the glass cloth is 20 μm or less, A glass cloth in which the average gap spacing in the weft and warp directions forming the basket holes is 162 to 240 μm and 65 to 200 μm, respectively. [2] Item 2. The glass cloth according to item 1, wherein the TEX value of the glass yarn is 0.2 to 2.0 g / 1000 m. [3] The average area of ​​the basket hole is 15,000 to 45,000 μm 2 3. The glass cloth according to item 1 or 2, [4] Area: 15,000 to 45,000 μm 2 4. The glass cloth according to any one of items 1 to 3, comprising the basket hole. [5] The glass yarn includes a plurality of glass filaments, In the glass yarn, The diameter of the glass filament is 2.0 to 4.5 μm, 5. The glass cloth according to any one of items 1 to 4, wherein the number of the glass filaments is 10 to 50. [6] 6. The glass cloth according to any one of items 1 to 5, wherein the ratio (short side / long side) in the basket hole is 0.4 to 0.8. [7] 7. The glass cloth according to any one of items 1 to 6, wherein the warp yarns have an average opening rate of 70 to 110% and / or the weft yarns have an average opening rate of 90 to 140%. [8] 8. The glass cloth according to any one of items 1 to 7, wherein the ratio of the glass yarns (weave density of warp yarns / weave density of weft yarns) is less than 1.0. [9] 9. The glass cloth according to any one of items 1 to 8, wherein the glass yarns are surface-treated with a silane coupling agent.

[10] The silane coupling agent is represented by the following general formula (1): X(R) 3-n SiY n ···(1) (Wherein X is an organic functional group having one or more amino groups; An organic functional group having one or more unsaturated double bond groups having radical reactivity, or an organic functional group having both one or more amino groups and one or more unsaturated double bond groups having radical reactivity; wherein each Y is independently an alkoxy group, n is an integer of 1 to 3, and each R is independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group. 10. The glass cloth according to item 9, comprising a silane coupling agent represented by the formula:

[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. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a glass cloth that can realize a prepreg and a printed wiring board having excellent dimensional stability and can suppress the occurrence of pinholes in the prepreg. Furthermore, according to the present invention, it is possible to provide a prepreg, a printed wiring board, an integrated circuit, and an electronic device obtained by using such a glass cloth. etc. can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described. However, the present invention is not limited to the present embodiment, and therefore, various modifications can be made to the present invention without departing from the gist of the present invention.

[0013] In this 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 this specification, the upper or lower limit of a numerical range described in stages may be replaced by the upper or lower limit of a corresponding numerical range described in another stage, and may also be replaced by the corresponding value described in the examples.

[0014] Furthermore, 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.

[0015] [First embodiment] The glass cloth of this embodiment is A glass cloth containing glass yarns as warp and weft yarns, The weave density of the warp and weft threads is 50 to 110 threads / 25 mm, The thickness of the glass cloth is 20 μm or less, The average gap intervals in the weft and warp directions forming the basket holes are 162 to 240 μm and 65 to 200 μm, respectively.

[0016] While controlling the weave density of the glass cloth to a high density is advantageous in that it makes it easier to suppress the occurrence of defects (pinholes) in the prepreg, the present inventors have found that it is also disadvantageous in that it makes it easier for a difference in the amount of thermosetting resin to occur between the front and back of the prepreg. In this regard, the present inventors have also found that controlling the weave density of the glass cloth to a high density not only makes it easier for a difference in the amount of thermosetting resin to occur between the front and back of the prepreg, but also makes it easier for the number of weave intersections to increase, which in this case increases the influence of residual deformation room due to the glass cloth stretching in the warp and weft directions, resulting in an adverse effect on the dimensional stability of the prepreg and the printed wiring board. According to the present embodiment achieved by the above-mentioned idea of ​​the inventors, by suitably adjusting the weave density of the glass yarns in the glass cloth and suitably opening the warp yarns, it is possible to simultaneously suppress the occurrence of pinholes in the prepreg and improve the dimensional stability. The glass cloth of the present embodiment can also meet the expectation of thinner thickness.

[0017] [Glass cloth] The glass cloth of this embodiment is a glass cloth containing glass yarns as warp and weft yarns, and in one aspect, is a glass cloth obtained by weaving glass yarns consisting of a plurality of glass filaments as warp and weft yarns. The glass cloth is preferably surface-treated with a surface treatment agent described below.

[0018] [Glass type] The glass type in the glass cloth, particularly the glass type in the glass cloth used for printed wiring boards, is preferably E-glass (alkali-free glass), and may also be L-glass, NE-glass, D-glass, L2-glass, S-glass, T-glass, silica glass, quartz glass, etc. As the glass type, from the viewpoint of easily achieving excellent dielectric properties, L-glass, L2-glass, silica glass, quartz glass, etc. are preferred, and among these, silica glass and quartz glass are more preferred. Furthermore, as the glass type, from the viewpoint of easily improving the dimensional stability of a laminate containing the glass cloth, S-glass, T-glass, silica glass, and quartz glass are preferred, and among these, silica glass and quartz glass are more preferred.

[0019] The amount of elements contained in glass can be measured by atomic absorption spectrometry, inductively coupled plasma (ICP) atomic emission spectrometry, etc. For example, it is possible to measure the amount of elements contained in each glass from a calibration curve created by using a sample with a known concentration and an apparatus such as ICP-AES or ICP-MS.

[0020] [Dielectric constant and dielectric loss tangent of glass at 10 GHz] The dielectric constant at 10 GHz of the glass used in the glass cloth of this embodiment is preferably 7.0 F / m or less, more preferably 6.0 or less, even more preferably 5.0 or less, even more preferably 4.5 or less, and particularly preferably 4.0 or less. Furthermore, the dielectric loss tangent at 10 GHz of the glass used in the glass cloth of this embodiment is preferably 0.0070 or less, more preferably 0.0065 or less, even more preferably 0.0045 or less, even more preferably 0.0030 or less, and particularly preferably 0.0020 or less. Having the dielectric constant and / or dielectric loss tangent of the glass within the above ranges facilitates reducing transmission loss in printed wiring boards.

[0021] [Coefficient of thermal expansion (CTE) of glass] The CTE of the glass used in the glass cloth of the present embodiment is preferably 6.0 ppm / ° C. or less, more preferably 5.0 ppm / ° C. or less, even more preferably 3.5 ppm / ° C. or less, even more preferably 3.0 ppm / ° C. or less, and particularly preferably 2.0 ppm / ° C. or less. When the CTE of the glass is within the above range, the dimensional stability of the prepreg and printed wiring board can be easily improved.

[0022] [TEX value of glass yarn] The TEX value (mass per 1000 m of glass yarn) of the glass yarn used in the glass cloth of this embodiment is preferably 0.2 to 2.0 g / 1000 m, more preferably 0.3 to 1.8 g / 1000 m, even more preferably 0.4 to 1.6 g / 1000 m, still more preferably 0.5 to 1.4 g / 1000 m, and particularly preferably 0.6 to 1.2 g / 1000 m. When the TEX value of the glass yarn is within the above range, it is easy to make the glass cloth, prepreg, and printed wiring board thinner.

[0023] [Glass cloth properties and composition] The mass of the glass cloth of this embodiment is 15.0 g / m as a mass per unit area according to JIS R3420. 2 From the viewpoint of reducing the thickness of the prepreg or printed wiring board containing the glass cloth, the mass of the glass cloth may be 12.0 g / m or less. 2 Less than 11.0 g / m 2 Less than 10.0 g / m is more preferable. 2 More preferably, 9.0 g / m 2 The lower limit of the mass per unit area of ​​the glass cloth is, for example, 0 g / m 2 More than or equal to 0.1 g / m 2 That's all.

[0024] The mass of the glass cloth is 15.0 g / m 2In order to control the above, it is preferable to use thin glass yarns as the glass yarns used for the warp and weft of the glass cloth. The diameter (filament diameter) of the glass filaments in the glass yarns is preferably 2.0 to 4.5 μm, more preferably 2.5 to 4.0 μm, further preferably 3.0 to 3.9 μm, and particularly preferably 3.2 to 3.8 μm. If the filament diameter is 2.0 μm or more, it is easy to ensure the breaking strength of the filaments, and therefore it is easy to suppress the generation of fluff. Furthermore, if the filament diameter is 4.5 μm or less, it is easy to keep the mass of the glass cloth to 15.0 g / m 2 It is difficult to control below this.

[0025] In the glass cloth of this embodiment, the warp openness is preferably 70 to 110% and / or the weft openness is 90 to 140%, more preferably 75 to 108% and / or 92 to 138%, even more preferably 80 to 106% and / or 94 to 135%, still more preferably 82 to 104% and / or 95 to 130%, and particularly preferably 85 to 103% and / or 96 to 128%. By controlling the opening degree of the warp and / or weft yarns of the glass cloth within the above range, it is easy to suppress both the occurrence of wrinkles during conveyance of the glass cloth and the occurrence of pinholes in the prepreg. When the opening degree is equal to or less than the upper limit of the above range, it is easy to prevent the opening degree from becoming excessively high, and therefore it is easy to suppress the occurrence of wrinkles during conveyance of the glass cloth. On the other hand, when the opening degree is equal to or more than the lower limit of the above numerical range, it is easy to reduce the occurrence rate of pinholes during prepreg production. The opening degree of the warp yarns can be adjusted in the glass cloth opening process, and can also be adjusted by pressing (nipping) the warp yarns with nip rolls at a predetermined load during warp warping, and by flattening the warp yarns, etc. From the viewpoint of facilitating adjustment of only the warp width, it is preferable to adjust the opening degree of the warp yarns by flattening them during warp warping. In this case, it is easy to obtain the advantage that the opening degrees of the warp yarns and weft yarns can be easily adjusted within the above range. The degree of opening of the weft yarn can be adjusted by the glass cloth opening process. For example, the degree of opening of the weft yarn can be easily adjusted within the above range by adjusting the pressure during high-pressure opening by spraying.

[0026] The average opening degree of the glass cloth of this embodiment is preferably 80 to 150%, more preferably 82% to 140%, even more preferably 84 to 135%, even more preferably 85 to 130%, and particularly preferably 86 to 128%. By setting the average opening degree of the glass cloth within the above range, it is easy to simultaneously suppress wrinkles during conveyance of the glass cloth and pinholes in the prepreg. The average opening degree of the glass cloth is expressed as the average value of the opening degrees of the warp yarns and the weft yarns.

[0027] The number of glass filaments used in the warp and weft of the glass cloth of this embodiment is preferably 10 to 50, more preferably 15 to 45, still more preferably 20 to 43, and particularly preferably 25 to 40. If the number of filaments is 50 or less, it is easy to prevent an insufficient expansion ratio when the glass cloth is subjected to flattening processing such as opening processing. Furthermore, if the number of filaments is 10 or more, it is easy to suppress the generation of fluff in the glass cloth. Glass filaments within the above number range can be bundled in the formation of glass yarns.

[0028] The weave density of the warp and weft of the glass cloth of this embodiment is in the range of 50 to 110 threads / 25 mm. From the viewpoint of easily exhibiting the effects of the present invention remarkably, the weave density of the warp and weft of the glass cloth of this embodiment is preferably 55 to 100 threads / 25 mm, more preferably 60 to 98 threads / 25 mm, still more preferably 65 to 96 threads / 25 mm, and particularly preferably 70 to 95 threads / 25 mm. The weave density of the warp threads and the weft threads may be different from each other, and the weave density of the warp threads may be higher than the weft threads, or the weave density of the warp threads may be lower than the weft threads. If the weave density of the warp and / or weft yarns is less than 50 threads / 25 mm, not only are pinholes more likely to occur in the prepreg, but the rigidity of the glass cloth used as the core material of the resin substrate is likely to be insufficient. As a result, this has an adverse effect on the stability of dimensional change. On the other hand, if the weave density of the warp and / or weft yarns is more than 110 threads / 25 mm, it becomes difficult to adjust the average gap spacing in the weft direction and / or the warp direction to fall within the range specified in this embodiment, making it difficult to improve the dimensional stability of the resin substrate.

[0029] The intersections of the warp and weft yarns of the glass cloth, where the warp and weft yarns overlap, are portions that constrain the glass yarns. At these intersections, there is some room for residual deformation. The present inventors have found that when producing a glass cloth, particularly when applying tension to the glass cloth, the residual room for deformation present near the intersections causes the glass cloth to elongate in the direction of the applied tension. Therefore, the present inventors have found that reducing the number of weave intersections of the glass cloth is effective in improving the dimensional stability of the glass cloth, prepreg, and printed wiring board. By setting the weave density of the warp and weft yarns of the glass cloth within the above range, pinholes do not occur in the prepreg, and as long as the weave density is within the above upper limit, the effect of excellent dimensional stability can be easily obtained.

[0030] The ratio (weave density of warp yarns / weave density of weft yarns) in the glass cloth of this embodiment is preferably less than 1.0, more preferably 0.9 or less, and particularly preferably 0.8 or less. This makes it easy to simultaneously suppress the occurrence of pinholes in the prepreg and improve the dimensional stability of the substrate.

[0031] The thickness of the glass cloth in this embodiment is 20 μm or less. The thickness of the glass cloth is more preferably 18 μm or less, even more preferably 16 μm or less, even more preferably 13 μm or less, and particularly preferably 10 μm or less. By adjusting the thickness of the glass cloth to 20 μm or less, it is possible to fully meet the expectations for thinner glass cloth, prepregs, and printed wiring boards. The thickness of the glass cloth may be 3 μm or more.

[0032] In this embodiment, the term "basket hole" refers to a gap between warp and weft yarns in the glass cloth. Furthermore, in this embodiment, the term "pinhole" refers to a void defect in the prepreg. Such a void defect can occur, for example, when the thermosetting resin does not fill the basket hole portion. Generally, when the average area of ​​the basket holes is reduced, pinholes are less likely to occur, but it is also difficult for varnish to flow from the front surface to the back surface (or from the back surface to the front surface) through the basket holes, which tends to cause thickness differences between the resin layers on both sides of the resulting prepreg, and therefore the dimensional stability is likely to decrease. In contrast to this, in this embodiment, in order to make it difficult for pinholes to occur in the prepreg and to improve the dimensional stability of the substrate, the average gap spacing in the weft direction (also referred to as the gap spacing between adjacent warp yarns) and the average gap spacing in the warp direction (also referred to as the gap spacing between adjacent weft yarns) are adjusted to within predetermined ranges by applying a fiber-spreading method described below.

[0033] The average gap spacing in the weft direction is 162 to 240 μm. It is more preferably 165 to 235 μm, even more preferably 170 to 230 μm, still more preferably 172 to 225 μm, and particularly preferably 174 to 220 μm. If the average gap spacing in the weft direction exceeds the above range, the glass cloth is likely to be insufficiently opened, and pinholes are therefore likely to occur in the prepreg. If the average gap spacing in the weft direction is below the above range, it becomes difficult for the varnish to flow from the front surface to the back surface of the glass cloth (or from the back surface to the front surface) during prepreg production. In this case, thickness differences are likely to occur between the resin layers on both sides in the obtained prepreg, and therefore dimensional stability is likely to decrease.

[0034] The average gap spacing in the warp direction is 65 to 200 μm. It is more preferably 70 to 195 μm, even more preferably 80 to 180 μm, even more preferably 85 to 170 μm, and particularly preferably 90 to 160 μm. If the average gap spacing in the warp direction exceeds the above range, the glass cloth is likely to be insufficiently opened, and pinholes are therefore likely to occur in the prepreg. If the average gap spacing in the warp direction is below the above range, it becomes difficult for the varnish to flow from the front surface to the back surface of the glass cloth (or from the back surface to the front surface) during prepreg production. In this case, thickness differences are likely to occur between the resin layers on both sides in the obtained prepreg, and therefore dimensional stability is likely to decrease.

[0035] The average gap spacing in the weft direction and the average gap spacing in the warp direction may be the same, or the average gap spacing in the weft direction may be larger than the average gap spacing in the warp direction, or the average gap spacing in the weft direction may be smaller than the average gap spacing in the warp direction. By comparing the average gap spacing in the weft direction with the average gap spacing in the warp direction, the larger one can be treated as the "long side" of the basket hole, and the smaller one can be treated as the "short side" of the basket hole. Note that if the average gap spacing in the weft direction and the average gap spacing in the warp direction are the same, any one of them can be treated as the "long side" and any other can be treated as the "short side." In this embodiment, the basket hole ratio (short side / long side) is preferably 0.4 to 0.8, and particularly preferably 0.5 to 0.7. When the basket hole ratio (short side / long side) is within the above range, it is easy to simultaneously suppress the occurrence of pinholes in the prepreg and improve the dimensional stability of the substrate.

[0036] The average area of ​​the pinholes is 15,000 to 45,000 μm 2 More preferably, 16,000 to 42,000 μm 2 and more preferably 1700 to 40,000 μm 2 and even more preferably 18,000 to 39,000 μm 2 and particularly preferably 20,000 to 37,000 μm 2 When the average area of ​​pinholes in the glass cloth is within the above range, it is easy to simultaneously suppress the occurrence of pinholes in the prepreg and improve the dimensional stability of the substrate.

[0037] [Surface treatment agent (silane coupling agent)] The glass fibers (including glass filaments) constituting the glass cloth are preferably surface-treated with a surface treatment agent such as a silane coupling agent. Examples of the silane coupling agent include those represented by the following general formula (1): X(R) 3-n SiY n ···(1) In formula (1), X represents an organic functional group having one or more amino groups, an organic functional group having one or more radically reactive unsaturated double bond groups, or an organic functional group having both one or more amino groups and one or more radically reactive unsaturated double bond groups; each Y represents independently an alkoxy group; n represents an integer of 1 to 3; and each R represents independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group. It is preferable to use a silane coupling agent represented by the following formula:

[0038] X in the general formula (1) above may be, for example, an organic functional group having at least one radically reactive unsaturated double bond group, such as a radically reactive carbon-carbon double bond, an organic functional group having at least one amino group, or an organic functional group having both at least one radically reactive unsaturated double bond group and at least one amino group. The amino group may be, for example, a primary amino group, a secondary amino group, a tertiary amino group, or a quaternary ammonium salt. Regarding Y in the general formula (1) above, any form of alkoxy group can be used, but for stabilizing the treatment of glass cloth, an alkoxy group having 5 or less carbon atoms is preferred.

[0039] As the surface treatment agent, the silane coupling agent represented by general formula (1) may be used alone, or two or more silane coupling agents having different X's in general formula (1) may be used in combination. Examples of the silane coupling agent represented by general formula (1) include N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, Examples thereof include known simple substances such as hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, and acryloxypropyltrimethoxysilane, or mixtures thereof.

[0040] [Glass cloth manufacturing method] One aspect of this embodiment is a method for producing a glass cloth. Such a manufacturing method includes, for example, a step of weaving glass yarns consisting of a plurality of glass filaments as warp and weft yarns to obtain a glass cloth (weaving step). It is preferable to further include at least one of a warping step, which is performed before the weaving step, in which the glass yarns are drawn and flattened, and then a sizing agent is applied thereto, and a step of thermally deoiling the binder component adhering to the glass yarns after the warping step and before, during, or after the weaving step (thermal deoiling step). It is also preferable to further include at least one of a step of surface-treating the glass surface with a surface treatment liquid after the thermal deoiling step (surface treatment step), and a step of opening the glass yarns after the surface treatment step. Including these steps makes it easier to improve the insulating reliability of the glass cloth.

[0041] [Glass yarn warping process] The manufacturing method of this embodiment may include a step of flattening a bundle of glass yarns, followed by a step of sizing the glass yarns (a treatment for applying a sizing agent to the glass yarns). This treatment allows the sizing agent to be applied (glued) to the glass yarns in a state where the yarn width of the glass yarns is widened, which facilitates widening of the yarn width in the glass cloth after weaving. In this case, the average gap spacing in the weft direction of the resulting glass cloth can be easily adjusted to within the above-mentioned range. Examples of methods for flattening the glass yarn bundle include a method of pressing the glass yarns with a nip roll. From the viewpoint of easily flattening the yarn bundle while suppressing the generation of fluff, the pressure applied to the glass yarns in this case is preferably 1.0 kg / cm. 2 ~6.0kg / cm 2 , more preferably 2.0 kg / cm 2 ~5.0kg / cm 2 , and more preferably 2.5 kg / cm 2 ~5.5kg / cm 2 is.

[0042] [Glass cloth weaving process] Glass yarns can be used as warp and weft yarns and woven into a loom. This allows, for example, the production of a plain weave woven fabric, glass cloth. The glass yarns used in the glass cloth fabric are preferably surface-treated with a sizing agent containing starch, polyvinyl alcohol, or the like as main components to suppress fluffing during spinning and warping of the glass yarns. In this specification, "glass cloth fabric" refers to glass cloth before being heated and deoiled.

[0043] [Step of reducing sizing agent (heat deoiling step)] The process of reducing the sizing agent can include, for example, a desizing process (thermal deoiling process) in which the glass cloth greige is heated at a temperature of 300°C to 1600°C. This facilitates the reduction of the sizing agent from the glass. The thermal deoiling conditions can be adjusted depending on the type of glass, the thickness of the glass cloth, and the like. By reducing the trace amounts of thermally oxidized degradation products of the sizing agent that remain physically attached to the surface of the glass, it becomes easier to effectively suppress an increase in the dielectric loss tangent of the resulting glass cloth. The heating time may be selected, for example, within the range of 1 minute to 72 hours, and may be adjusted appropriately depending on the heating temperature, the type of glass, and the like.

[0044] The means for heating the glass cloth greige may be any means capable of heating the glass cloth greige so that the thermal deoiling temperature is in the range of 300°C to 1600°C, and known heating methods, heating media, heating mechanisms, heating devices, and heating components can be used. Examples of heating means include (1) heating the glass cloth greige in a heating furnace, (2) bringing the glass cloth greige into contact with a heating section, and (3) applying high-temperature steam to the glass cloth greige. Heating the glass cloth greige so that the thermal deoiling temperature is in the range of 300 to 1600°C facilitates efficient removal of organic matter adhering to the surface of the glass cloth greige and shortens the time required for organic matter removal. Heating the glass cloth greige can be carried out sequentially or continuously in a closed or open system, or in a combination of a closed and an open system.

[0045] In the case of a closed system, it is preferable to place the glass cloth fabric in a heating furnace from the viewpoint of suitable heating by the heating means, and / or it is preferable to heat the glass cloth fabric while storing it in a rolled state from the viewpoint of storage space and heating range. Also, it is preferable to heat the glass cloth fabric while transporting it in the heating furnace from the viewpoint of easily increasing the efficiency of removing organic substances and shortening the removal time of organic substances.

[0046] In the case of an open system, it is preferable to heat the glass cloth while transporting it from the viewpoint of the heated area. The transport of the glass cloth can be carried out, for example, by an unwinding mechanism and a winding mechanism, for example, a roll-to-roll system.

[0047] [Glass cloth spreading process] In this step, the glass cloth is subjected to an opening treatment. By carrying out this step, it is easy to improve the resin impregnation property of the glass cloth, and in turn, it is easy to adjust the average gap spacing in the weft direction and the warp direction of the obtained glass cloth to be within the above-mentioned range. Examples of the opening treatment include an opening treatment in which water pressure is applied to the glass cloth, an opening treatment using high-frequency vibrations using water (e.g., degassed water, ion-exchanged water, deionized water, electrolytic cation water, electrolytic anion water, etc.) as a medium, and a processing treatment using pressure with a roll. Such an opening treatment may be carried out simultaneously with weaving or after weaving. Such an opening treatment may be carried out before or after thermal deoiling, or may be carried out simultaneously with thermal deoiling. Furthermore, such an opening treatment may be carried out simultaneously with or after the surface treatment step.

[0048] From the viewpoint of easily adjusting the average gap spacing in the weft and warp directions of the glass cloth within the above ranges, the above-mentioned fiber-spreading step preferably includes a step of cleaning and opening the glass cloth while conveying it in a liquid after the thermal deoiling step and before the surface treatment step. Furthermore, the conveying speed of the glass cloth in this step is preferably 50 m / min or less. By carrying out the cleaning and opening treatment of the glass cloth after the thermal deoiling step and before the surface treatment step, it is easy to clean and remove combustion residues from the thermal deoiling step, and in this case, it is easy to prevent adhesion between the filaments due to the combustion residue acting as an adhesive. Furthermore, by opening the glass cloth before the surface treatment, it is easy to prevent adhesion between the filaments in the surface treatment step. As a result, not only is it easy to adjust the average gap spacing in the weft and warp directions of the glass cloth, but it is also easy to improve the insulation reliability.

[0049] The cleaning and opening step of the glass cloth preferably includes a step of irradiating ultrasonic waves in a liquid to the glass cloth after the thermal deoiling step and before the surface treatment step, thereby cleaning mainly the combustion residue of the thermal deoiling from the glass cloth and opening the glass (ultrasonic cleaning). Preferably, the cleaning and opening step includes a step of treating the glass cloth by transporting it in a roll-to-roll manner in a liquid to which ultrasonic waves are irradiated by an ultrasonic oscillator.

[0050] Although either water or an organic solvent can be used as the liquid for ultrasonic cleaning, it is preferable to use a liquid containing water as the main component from the viewpoints of safety and global environmental protection. To improve the cleaning efficiency, surfactants, pH adjusters, etc. can also be added to the liquid used for cleaning.

[0051] Although there are no particular restrictions on the temperature of the liquid used in ultrasonic cleaning, from the viewpoint of enhancing the cleaning effect, it is preferable that the temperature be 5° C. or higher. Furthermore, from the viewpoint of safety, the temperature of the liquid used for cleaning is preferably 60° C. or lower.

[0052] The glass cloth can be washed by running it through a liquid to which ultrasonic waves are applied by an ultrasonic oscillator. The line tension acting on the warp yarns during the washing process is preferably 30 to 500 N / m.

[0053] Ultrasonic cleaning can be performed using ultrasonic waves having a frequency of 20 to 200 kHz. The ultrasonic frequency is preferably 20 to 50 kHz, and more preferably 20 to 30 kHz. Using ultrasonic waves having a frequency of 20 to 200 kHz makes it easy to perform cleaning treatment while preventing major defects such as warping of the glass cloth.

[0054] For ultrasonic cleaning, 0.07 to 3.60 W / cm 2 The ultrasonic output is preferably in the range of 0.14 to 2.16 W / cm. 2 , and more preferably in the range of 0.21 to 1.44 W / cm 2 The ultrasonic output is 0.07W / cm2 If it is above 3.60W / cm, it is easy to clean well and the ultrasonic output is 3.60W / cm 2 If the thickness is less than this, it is easy to perform uniform cleaning while preventing major defects such as twisted weave.

[0055] The conveying speed of the glass cloth during ultrasonic cleaning is preferably 50 m / min or less, more preferably 40 m / min or less, and even more preferably 30 m / min or less. If the conveying speed of the glass cloth is 50 m / min or less, the glass cloth or its intermediate product can be easily cleaned and opened. In addition, the generation of fluff and misalignment due to damage during conveyance can be easily suppressed.

[0056] The liquid used for ultrasonic cleaning usually contains dissolved nitrogen and air, the main components of which are oxygen. The amount of dissolved oxygen (mass ratio) is preferably 1 to 20 ppm, more preferably 3 to 17 ppm, and even more preferably 4 to 14 ppm. By controlling the amount of dissolved oxygen, it is easy to indirectly control the amount of dissolved gas, and in this case, it is easy to control the degree to which ultrasonic waves are attenuated by the dissolved gas. If the amount of dissolved oxygen is 1 ppm or more, it is easy to perform a uniform fiber-opening process. If the amount of dissolved oxygen is 20 ppm or less, it is easy to impart a good cleaning effect to fiber fabrics. In other words, if the amount of dissolved oxygen is 1 to 20 ppm, it is easy to obtain a uniform and good fiber-opening effect.

[0057] [Glass cloth surface treatment process] The surface treatment method for glass cloth may include, for example, a coating step in which the surface of the glass filaments is covered with a treatment liquid containing a silane coupling agent, and a fixing step in which the silane coupling agent is fixed to the surface of the glass filaments by heating and drying. The treatment liquid preferably contains 0.1% by mass to 3.0% by mass of the silane coupling agent. It is preferable that the surface of the glass filaments is almost completely covered with the silane coupling agent by the coating step.

[0058] Possible methods for applying the treatment solution to the glass cloth include (a) a method in which the treatment solution is collected in a bath and the glass cloth is immersed in the treatment solution and passed through the bath (hereinafter referred to as the "immersion method"), and (b) a method in which the treatment solution is applied directly to the glass cloth using a roll coater, a die coater, a gravure coater, etc. When applying the treatment solution by the immersion method (a), it is preferable to select the immersion time of the glass cloth in the treatment solution to be 0.5 seconds or more and 1 minute or less.

[0059] The heat drying temperature is preferably 90°C or higher, more preferably 100°C or higher, so that the reaction between the silane coupling agent and the glass is sufficiently carried out, and is preferably 300°C or lower, more preferably 200°C or lower, so as to prevent deterioration of the organic functional groups of the silane coupling agent.

[0060] The surface treatment method for glass cloth may include a step of washing at least a part of the silane coupling agent adhered to the surface of the glass filaments with a washing liquid such as water, and a step of adjusting the amount of the silane coupling agent adhered (adjustment step). The washing can be performed with a high-pressure spray of water or the like.

[0061] As the solvent for dissolving or dispersing silane coupling agent, water or organic solvent can be used, and from the viewpoint of safety and global environmental protection, it is preferable to use water as the main solvent.As the method for obtaining the treatment solution with water as the main solvent, it is preferable to either directly add silane coupling agent to water, or to dissolve silane coupling agent in a water-soluble organic solvent to form an organic solvent solution, and then add this organic solvent solution to water.In order to improve the water dispersibility or stability of silane coupling agent in the treatment solution, it is also possible to use surfactant in combination.

[0062] [Fiber-spreading process after surface treatment] In the opening step of the glass filaments after the application of the surface treatment agent, for example, the glass cloth can be opened using 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 opening process, the yarn width tends to be wider. In order to suppress the generation of fluff in the glass cloth due to the opening process, it is preferable to take measures such as reducing friction with contacting members when weaving the glass yarns, optimizing the surface treatment agent, and increasing the amount of adhesion.

[0063] [About each process] The steps described above do not necessarily have to be performed separately, and multiple steps can be combined into one step. The composition of the glass cloth usually does not change before and after the fiber-spreading process. The method for producing glass cloth can also include any steps other than the steps described above. For example, after the fiber-spreading process, a slitting process can be included to cut the cloth to a predetermined width. If possible, the order of the steps described above can be reversed.

[0064] According to the method for producing a glass cloth described above, it is easy to adjust the average gap spacing in the weft direction and the warp direction to fall within the above-mentioned ranges, and therefore it is possible to obtain a glass cloth that can simultaneously suppress the occurrence of pinholes in the prepreg and improve the dimensional stability of the substrate. The glass cloth of this embodiment can be used, for example, as a material for producing a printed wiring board.

[0065] [Prepreg] Another aspect of this embodiment is a prepreg containing the glass cloth and a thermosetting resin. The prepreg can be manufactured according to a standard method. For example, a thermosetting resin varnish (also simply referred to as "varnish" in this specification) is prepared by diluting a matrix resin such as an epoxy resin with an organic solvent. The glass cloth is impregnated with the varnish, and the organic solvent is evaporated in a drying oven. The thermosetting resin is then cured to a B-stage (semi-cured state). The amount of thermosetting resin attached to the glass cloth is preferably adjusted so that the mass of the varnish solids is 20 to 80% by mass of the total mass of the varnish solids and the glass cloth.

[0066] Examples of matrix resins used in prepregs include thermosetting resins such as epoxy resin, unsaturated polyester resin, polyimide resin, bismaleimide triazine (BT) resin, and cyanate resin, thermoplastic resins such as polyphenylene oxide (PPO) resin, polyetherimide resin, and fluororesin, and mixtures of these resins. Resins containing inorganic fillers such as aluminum hydroxide, talc, and silica filler may also be used.

[0067] [Printed wiring board] Another aspect of this embodiment is a printed wiring board including the prepreg described above. The printed wiring board includes one or more of the prepregs described above. That is, the printed wiring board has the glass cloth described above and a cured product of the matrix resin composition impregnated into the glass cloth. The printed wiring board of this embodiment has high adhesion to resins and excellent dielectric properties.

[0068] [Integrated circuits and electronic devices] A further aspect of this embodiment is an integrated circuit and an electronic device including the printed wiring board. The integrated circuit and the electronic device obtained using the printed wiring board of this embodiment each have various excellent properties. [Example]

[0069] Examples and comparative examples for illustrating this embodiment are as follows. However, this embodiment is not limited to only the following examples. With regard to the examples and comparative examples, various productions, measurements, evaluations, etc. were carried out at room temperature (25°C) and atmospheric pressure unless otherwise specified.

[0070] [Measurement and Evaluation] [Physical Properties] [TEX value, number of filaments, weaving density, and thickness] The physical properties of the glass yarn and glass cloth, specifically, the TEX value, the number of filaments, the weaving density of the warp and weft yarns (weave density), and the thickness of the glass cloth were measured in accordance with JIS R3420.

[0071] [Average filament diameter of glass yarn] Cross sections of 30 glass fiber bundles at arbitrary positions in the glass fiber were obtained and observed with a scanning electron microscope. The average filament diameter was calculated from the observed image, and the average filament diameter (μm) of the glass fiber was determined.

[0072] [Average number of glass filaments] The number of filaments measured in accordance with JIS R3420 was averaged to determine the average number of filaments.

[0073] [Warp and weft width] A camera with a field of view of approximately 2.3 x 1.7 mm and a resolution of 2.26 μm / Pixel was scanned in the MD or TD direction of the glass cloth, taking images at 1 mm intervals. From the obtained data, the average yarn width (μm) was calculated for each of the warp and weft yarns of the glass cloth. The average yarn width (μm) was calculated using yarn widths obtained from more than 100 glass yarns.

[0074] [Glass cloth opening rate] The degree of opening (%) of the warp and weft of the glass cloth was calculated using the following formula: Warp opening rate [%] = {warp width [μm] / (number of warp filaments [lines] × warp filament diameter [μm])} × 100 Weft opening rate [%] = {Weft width [μm] / (number of weft filaments [pieces] × weft filament diameter [μm])} × 100 It was calculated by: Then, the average value of the degree of opening of each of the warp yarns and the weft yarns was calculated, and the average degree of opening (%) of the glass cloth was determined from this.

[0075] [Average gap spacing in the warp and weft directions in the glass cloth] The average gap spacing in the warp and weft directions of the glass cloth is calculated using the following formula: Average gap spacing in the warp direction (gap spacing between adjacent weft threads) [μm] = {25000 - (weft thread width [μm] x weft weave density [threads / 25mm])} / (weft weave density [threads / 25mm] - 1) Average gap spacing in the weft direction (gap spacing between adjacent warp threads) [μm] = {(25,000 - warp thread width [μm] x warp thread weave density [threads / 25mm])} / (warp thread weave density [threads / 25mm] - 1) It was calculated by:

[0076] [Average area of ​​basketball halls and ratio of short side to long side in basketball halls] The average area of ​​the basket holes of the glass cloth is calculated using the following formula: Average area of ​​the basket hole [μm 2 ] = Average gap spacing in the warp direction [μm] × Average gap spacing in the weft direction [μm] It was calculated by:

[0077] Comparing the average gap spacing [μm] in the warp direction with the average gap spacing [μm] in the weft direction, the longer side (in this example, the average gap spacing in the warp direction) was treated as the long side, and the shorter side (in this example, the average gap spacing in the weft direction) was treated as the short side. The ratio (short side / long side) in the basketball hole is calculated using the following formula: Ratio in basket hole (short side / long side) = average gap spacing in weft direction [μm] / average gap spacing in warp direction [μm] It was calculated by:

[0078] [Dielectric constant and dielectric loss tangent] The dielectric constant and dielectric loss tangent of each glass were measured in accordance with IEC 62562. Specifically, glass plate samples were prepared to the size required for measurement using a split cylinder resonator. These samples were stored in a constant temperature and humidity oven at 23°C and 50% RH for 8 hours or more, and then conditioned. The dielectric properties were then measured at 10 GHz using a split cylinder resonator (EM Lab) and an impedance analyzer (Agilent Technologies). Each sample was measured five times, and the average value was calculated.

[0079] [Bulk dielectric constant and 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 constant and bulk dielectric loss tangent at 10 GHz in the same manner as in the measurement of the dielectric loss tangent. In the table, the bulk dielectric constant is shown in the "Dk@10GHz" column, and the bulk dielectric loss tangent is shown in the "Df@10GHz" column.

[0080] [Coefficient of thermal expansion (CTE) of glass] Measurement was performed in accordance with JIS R3102-1995. Specifically, a block of glass cullet was processed into a 4 mm x 4 mm x 20 mm test piece using a diamond cutter and a polishing machine, and a test piece for CTE measurement was prepared using this. The obtained test piece was heated at a temperature increase rate of 5°C / min, and the amount of elongation at temperatures in the range of 50 to 200°C was measured, and the thermal expansion coefficient of the glass was calculated from this amount of elongation.

[0081] [Example 1] [Preparation of glass cloth] The glass type was Glass A shown in the table below, and the warp yarns were prepared using glass yarns with an average filament diameter of 3.6 μm, 38 filaments, and a twist of 1.0 Z. The warp yarns were aligned at a predetermined conveying speed and pressed (nipped) with nip rolls at a predetermined load to flatten the glass yarns. Here, the warping conditions for the warp yarns are as follows: (Warping conditions) Warp conveying speed: 60m / min Nipping load: 3.0kg / cm 2

[0082] Thereafter, a sizing agent containing polyvinyl alcohol (PVA) resin as a main component was applied to the glass yarns by the following procedure. Specifically, an aqueous solution containing 5% by mass of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) was prepared, and 2% by mass of hydrogenated castor oil was blended into this aqueous solution as a lubricant to obtain a sizing agent. The sizing agent, which had been kept at 60°C, was applied to the glass yarns, which were then dried, thereby carrying out a sizing treatment. An air jet loom was then used to weave a glass cloth with a weave density of 75 warp threads / mm and 100 weft threads / mm. The weaving was carried out so that the cloth width was 1,300 mm. The same glass yarns as the warp threads were used as the weft threads.

[0083] The obtained glass cloth was heated in a rolled state at 360°C for 72 hours to remove the sizing agent adhering to the glass surface (de-oiling and de-oiling process). Next, the glass cloth was run in water at a conveying tension of 150 N and a line speed of 30 m / min, while being heated at a frequency of 25 GHz and an output of 0.72 W / cm. 2 The residue was washed away by irradiating the fibers with ultrasonic waves (cleaning and opening process).

[0084] Next, a treatment solution was prepared by dispersing 1.0 mass% of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) in pure water adjusted to pH = 3 using acetic acid. The cloth was immersed in the treatment solution, squeezed out, and then heated and dried at 130 ° C for 60 seconds to fix the silane coupling agent. The cloth was then sprayed with 2.0 kg / cm 2 (opening step after surface treatment), and then dried at 130°C for 1 minute to obtain a glass cloth.

[0085] [Preparation of prepreg] An epoxy resin varnish was prepared by mixing 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. Then, glass cloth was immersed in the epoxy resin varnish while being conveyed at a speed of 3 m / min. The glass cloth was passed through a slit whose gap was adjusted so that the amount of epoxy resin varnish was 68% by mass, and excess varnish was scraped off from the glass cloth. The glass cloth was then dried at a drying temperature of 170°C for 1 minute and 30 seconds. This resulted in a prepreg.

[0086] [Ratio of front and back resin layers in prepreg] The obtained prepreg was embedded in resin (Epomount base resin, curing agent II, manufactured by Refine Tech Co., Ltd.), and the cross section of the prepreg for each resin was cut out so that the circularity of the glass filaments was 0.9 or more, and then polished. The cross section was observed with an optical microscope at a magnification (e.g., 1000x) to obtain an observation image including the glass cloth layer and the resin layer on the glass cloth layer. In the observation image, the thicknesses of the resin layers on the front and back of the prepreg were determined. The lower of the obtained values ​​was then divided by the higher value to calculate the resin layer ratio.

[0087] In this case, the region up to the region where the glass filaments were closest to the resin layer in the observation area was defined as the "glass cloth layer," and the region closer to the resin layer than that was defined as the "resin layer," and the thickness of the resin layer on both sides was determined. This operation was performed 30 times on both sides, changing the measurement position, and the ratio of the resin layers on the front and back of the prepreg was calculated by averaging the obtained values.

[0088] [Prepreg non-defective rate (pinhole suppression rate)] From the obtained prepreg, samples measuring 400 mm x 400 mm were obtained. After obtaining a total of 150 samples of the above size, the number of pinholes in each sample was counted by visual inspection. Prepregs with four or fewer pinholes per prepreg were considered to be good products, and the rate (%) of good products out of the 150 prepregs was evaluated.

[0089] [Method for evaluating the dimensional stability of substrates] A 12 μm copper foil was placed on both sides of one of the prepregs, measuring 340 mm in length and 340 mm in width, and the prepreg was heated and pressed at 175°C and 3.9 MPa for 1 hour to obtain a 1-ply substrate for evaluating dimensional stability.

[0090] On the obtained substrate, a total of nine gauge marks were made at 125 mm intervals, three in the warp direction and three in the weft direction, and the gauge mark distance between two adjacent gauge marks was measured at six points in each of the warp and weft directions (measured value a). Next, the copper foil was removed by etching, and the substrate was heated at 170°C for 30 minutes. Thereafter, the gauge mark distance was measured again (measured value b). Then, the following formula was used: Dimensional change rate (%) = {(difference between measured values ​​a and b) / measured value a} (%) The dimensional change rate was calculated by the above method.

[0091] Then, for each of the warp direction and weft direction, the absolute value after subtracting the minimum value from the maximum value of the six dimensional change rates was found, and this value was calculated as the "variation in dimensional change rate."

[0092] [Example 2] to [Example 3] A glass cloth was obtained in the same manner as in Example 1, except that the items shown in the table below, such as the glass yarn and the weaving density of the warp and weft yarns in the glass cloth, were changed as shown in the table below.

[0093] [Example 4] A glass cloth was obtained in the same manner as in Example 1, except that the items described in the table below, such as the glass yarn and the weaving density of the warp and weft yarns in the glass cloth, were changed as shown in the table below, and the warping conditions during warping of the warp yarns were changed as follows. (Warping conditions) Warp conveying speed: 60m / min Nipping load: 4.0kg / cm 2 0000 [Example 5] A glass cloth was obtained in the same manner as in Example 1, except that the items shown in the table below, such as the glass yarn and the weaving density of the warp and weft yarns in the glass cloth, were changed as shown in the table below.

[0094] [Example 6] A glass cloth was obtained in the same manner as in Example 1, except that the items described in the table below, such as the glass yarn and the weaving density of the warp and weft yarns in the glass cloth, were changed as shown in the table below, and the warping conditions during warping of the warp yarns were changed as follows. (Warping conditions) Warp conveying speed: 30m / min Nipping load: 4.2kg / cm 2

[0095] [Example 7] A glass cloth was obtained in the same manner as in Example 1, except that the items described in the table below, such as the glass yarn and the weaving density of the warp and weft yarns in the glass cloth, were changed as shown in the table below, and the warping conditions during warping of the warp yarns were changed as follows. (Warping conditions) Warp conveying speed: 20m / min Nipping load: 4.6kg / cm 2

[0096] [Example 8] A glass cloth was obtained in the same manner as in Example 1, except that the items described in the table below, such as the glass yarn and the weaving density of the warp and weft yarns in the glass cloth, were changed as shown in the table below, and the warping conditions during warping of the warp yarns were changed as follows. (Warping conditions) Warp conveying speed: 40m / min Nipping load: 3.0kg / cm 2

[0097] [Comparative Example 1] The warp yarns were warped using the glass A listed in the table below, with an average filament diameter of 3.6 μm, 38 filaments, and a twist of 1.0Z. A sizing agent primarily composed of polyvinyl alcohol (PVA) resin was applied to the warp yarns, which were aligned at a conveying speed of 60 m / min, using the following procedure. A 5% by mass aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) was prepared, and 2% by mass of hydrogenated castor oil was blended into this aqueous solution as a lubricant to obtain a sizing agent. The sizing agent, which had been kept at 60°C, was applied to the glass yarns, which were then dried to perform a sizing treatment. A glass cloth was then woven using an air jet loom at a weave density of 103 warp threads / mm and 108 weft threads / mm. The weaving was performed to obtain a cloth width of 1,300 mm. The same glass yarn as the warp threads was used as the weft.

[0098] The obtained glass cloth greige was heated in a rolled state at 360° C. for 72 hours to remove the sizing agent adhering to the glass surface (de-oiling and de-oiling step). Next, a treatment solution was prepared by dispersing 1.0 mass% of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) in pure water adjusted to pH = 3 with acetic acid. The cloth was immersed in the treatment solution, squeezed out, and then heated and dried at 130 ° C for 60 seconds to fix the silane coupling agent. The cloth was then sprayed with 2.0 kg / cm 2 (opening step after surface treatment), and then dried at 130°C for 1 minute to obtain a glass cloth.

[0099] Comparative Example 2 The glass yarns were warped using the glass A listed in the table below, with an average filament diameter of 4.0 μm, 34 filaments, and a twist of 1.0Z. A sizing agent primarily composed of polyvinyl alcohol (PVA) resin was applied to the warp yarns, which were aligned at a conveying speed of 60 m / min, using the following procedure. A 5% by mass aqueous solution of PVA (trade name: PVA403, manufactured by Kuraray Co., Ltd.) was prepared, and 2% by mass of hydrogenated castor oil was blended into this aqueous solution as a lubricant to obtain a sizing agent. The sizing agent, which had been kept at 60°C, was applied to the glass yarns, which were then dried to perform a sizing treatment. A glass cloth was then woven using an air jet loom at a weave density of 105 warp threads / mm and 105 weft threads / mm. The weaving was performed to obtain a cloth width of 1,300 mm. The same glass yarns as the warp threads were used as the weft threads.

[0100] The obtained glass cloth greige was heated in a rolled state at 400° C. for 40 hours to remove the sizing agent adhering to the glass surface (de-oiling and de-oiling step). Next, a treatment solution was prepared by dispersing 1.0 mass% of N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) in pure water adjusted to pH = 3 with acetic acid. The cloth was immersed in the treatment solution, squeezed out, and then heated and dried at 130 ° C for 60 seconds to fix the silane coupling agent. The cloth was then sprayed with 10 kg / cm 2 (opening step after surface treatment), and then dried at 130°C for 1 minute to obtain a glass cloth.

[0101] Comparative Example 3 A glass cloth was obtained in the same manner as in Example 1, except that the glass yarns were not flattened by nip rolls during warping of the warp yarns, and the cleaning and opening step was not carried out.

[0102] Comparative Example 4 A glass cloth was obtained in the same manner as in Comparative Example 3, except that the high-pressure opening after the surface treatment (opening step after the surface treatment) was not carried out.

[0103] Comparative Example 5 A glass cloth was obtained in the same manner as in Example 1, except that the items shown in the table below, such as the glass yarn and the weaving density of the warp and weft yarns in the glass cloth, were changed as shown in the table below.

[0104] Comparative Example 6 A glass cloth was obtained in the same manner as in Example 1, except that the items shown in the table below, such as the glass yarns and the weaving densities of the warp and weft yarns in the glass cloth, were changed as shown in the table below, that the glass yarns were not flattened by nip rolls during warping of the warp yarns, and that the cleaning and opening process was not performed.

[0105] The results of the measurements and evaluations are shown in the table below. In the table, the yield rate of the prepreg (the rate at which pinholes are suppressed) can be confirmed under "yield rate," and the dimensional stability of the board can be confirmed under "variation in dimensional change rate." Since using a prepreg with excellent dimensional stability makes it easy to produce a board with excellent dimensional stability, when the "variation in dimensional change rate" result for the board is good, it can be inferred that the prepreg, which is the raw material for the board, also has excellent dimensional stability.

[0106] [Table 1]

[0107] [Table 2]

[0108] [Table 3]

[0109] From the results in the above table, it was confirmed that the examples make it possible to realize prepregs and printed wiring boards having excellent dimensional stability, and also to provide glass cloths that can suppress the occurrence of pinholes in the prepregs. In particular, according to the examples, it was confirmed that both the "variation in the dimensional change rate in the warp direction (warp direction)" and the "variation in the dimensional change rate in the weft direction (weft direction)" were below predetermined values. [Industrial Applicability]

[0110] The present invention can be suitably used in fields related to glass cloth, prepregs, printed wiring boards, and the like.

Claims

1. A glass cloth containing glass yarns as warp and weft yarns, The weaving density of the warp yarns and the weft yarns is 50 to 110 yarns / 25 mm, The thickness of the glass cloth is 20 μm or less, The glass cloth has average gap intervals in the weft and warp directions forming basket holes of 162 to 240 μm and 65 to 200 μm, respectively.

2. The glass cloth according to claim 1, wherein the TEX value of the glass yarn is 0.2 to 2.0 g / 1000 m.

3. The average area of ​​the basket hole is 15,000 to 45,000 μm ２ The glass cloth according to claim 1 or 2,

4. Area is 15,000 to 45,000 μm ２ The glass cloth according to claim 1 or 2, comprising the basket hole having a diameter of 1 / 2 mm.

5. The glass yarn includes a plurality of glass filaments, In the glass yarn, The diameter of the glass filament is 2.0 to 4.5 μm, 3. The glass cloth according to claim 1, wherein the number of the glass filaments is 10 to 50.

6. 3. The glass cloth according to claim 1, wherein the ratio (short side / long side) in the basket hole is 0.4 to 0.

8.

7. 3. The glass cloth according to claim 1, wherein the average degree of opening of the warp yarns is 70 to 110% and / or the average degree of opening of the weft yarns is 90 to 140%.

8. 3. The glass cloth according to claim 1, wherein the ratio (weave density of warp yarns / weft yarns) in the glass yarns is less than 1.

0.

9. 3. The glass cloth according to claim 1, wherein the glass yarns are surface-treated with a silane coupling agent.

10. The silane coupling agent is represented by the following general formula (1): X (R) ３－ｎ Yes ｎ ・・・(1) (Wherein X is an organic functional group having one or more amino groups; an organic functional group having one or more unsaturated double bond groups having radical reactivity, or an organic functional group having both one or more amino groups and one or more unsaturated double bond groups having radical reactivity; wherein each Y is independently an alkoxy group, n is an integer of 1 to 3, and each R is independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group. The glass cloth according to claim 9, comprising a silane coupling agent represented by the formula:

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

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

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

14. An electronic device comprising the printed wiring board according to claim 12.

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