JP6818278B1 - Glass cloth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both suppression of pinhole generation and suppression of vertical wrinkle generation even when a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg. The main issue is to provide a glass cloth that can achieve this. SOLUTION: A glass cloth having a mass of 10 g / m2 or less has a gap design value Iwd between adjacent warp threads of 95 μm or less and a gap design value Ifd between adjacent weft threads of 95 μm or less. The ratio (Iw / If) between the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads of the glass cloth is 1.10 or more and 1.60 or less. A glass cloth having a basket hole area ratio of 12% or more and 20% or less. [Selection diagram] None

Description

The present invention relates to glass cloth.

In recent years, printed wiring boards have been required to be lighter in weight with the miniaturization of electronic devices, and the materials used are also required to have a low mass. In order to manufacture a printed wiring board, a prepreg in which a glass cloth is impregnated with a resin is used. However, as the weight of the electronic device is reduced, the prepreg is also required to have a low mass. The glass cloth contained in the prepreg is also required to have a low mass.

As a low-mass glass cloth, for example, a glass cloth satisfying the following (i) to (iv) is known (see, for example, Patent Document 1).
(I) The degree of openness represented by the following formula (1) is 70 to 90% for the warp and 95 to 120% for the weft.
Fineness (%) = {(25 x 1000) / WD-I} / (D x N) x 100 (1)
WD: Weaving density of warp or weft (book / 25 mm)
I: Gap spacing between adjacent warp or weft (μm)
D: Average filament diameter (μm) of warp or weft
N: Average number of filaments of warp or weft (thread)
(Ii) Either the gap spacing between the adjacent warp threads or the gap spacing between the adjacent weft threads is 100 μm or less.
(Iii) The thickness measured according to JIS R 3420: 2013 7.10.1 is 14 μm or less.
(Iv) The cross mass measured according to JIS R 3420: 2103 7.2 is 11 g / m ² or less.

According to the glass cloth of Patent Document 1, the occurrence of pinholes is suppressed when a thin prepreg having a thickness of 20 μm or less and a substrate using the prepreg are used while reducing the thickness to 14 μm or less. It is said that it can be done.

Further, as a low-mass glass cloth, glass filaments having a diameter in the range of 3.0 to 4.2 μm are composed of warp threads and weft threads in which 14 to 55 threads are focused, and the weaving density of the warp threads and weft threads is formed. Is in the range of 86 to 140 lines / 25 mm, has a thickness in the range of 7.5 to 12.0 μm, and has a mass in the range of 6.0 to 10.0 g per 1 m ² , and has a thickness of glass cloth as warp. It is shown as the value divided by the average value of the diameter of the glass filament and the diameter of the glass filament of the weft (glass cloth thickness / {(the diameter of the glass filament of the warp + the diameter of the glass filament of the weft) / 2}). A glass cloth having an average number of steps in the range of 2.00 or more and less than 3.00, and the degree of opening of the warp (thread width of the warp / (diameter of the glass filament constituting the warp × number of glass filaments constituting the warp). )) And the openness of the weft (the width of the weft / (the diameter of the glass filaments constituting the weft x the number of glass filaments constituting the weft))) ((openness of the warp x openness of the weft)) The average openness indicated by 1/2) is in the range of 1.00 to 1.300, and is indicated by the ratio of the warp yarn width to the weft yarn width (warp yarn width / weft yarn width). Glass cloths having a yarn width ratio in the range of 0.720 to 0.960 are known (see, for example, Patent Document 2).

According to the glass cloth of Patent Document 2, even if the average number of stages is less than 3.00, the occurrence of pinholes can be suppressed in the prepreg using the glass cloth, and the fluffing of the glass cloth is small. It is said that the excellent appearance quality of prepreg can be maintained.

JP-A-2017-43873 Japanese Unexamined Patent Publication No. 2018-21274

From the viewpoint of insulation reliability, a low-mass prepreg is often used as having a low mass ratio of glass cloth, for example, the ratio of the mass of the glass cloth to the total mass of the prepreg is about 10 to 40% by mass. .. However, as a result of examination by the present inventor, the glass cloths of Patent Documents 1 and 2 are obtained by impregnating and curing a resin solution on the assumption that the mass ratio of the glass cloth is low when the prepreg is formed. I learned that wrinkles (vertical wrinkles) that run in the direction of the machine may occur.

Therefore, the present invention solves the above-mentioned problems and suppresses the occurrence of pinholes even when a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg. The main issue is to provide a glass cloth that can be compatible with the suppression of vertical wrinkles.

When the present inventor investigated the cause of the above problem, when a low-mass glass cloth was impregnated with a resin solution so as to have a low mass ratio of the glass cloth and cured, the warp direction (glass) of the glass cloth was examined. The tension in the weft direction (glass cloth width direction) is significantly lower than the tension in the cloth length direction. Then, in the glass cloth of Patent Document 1, it was considered that the wefts tend to move slightly in the width direction of the glass cloth due to the curing shrinkage when the resin impregnated in the glass cloth is cured, and as a result, the vertical wrinkles are likely to occur. Specifically, the glass cloth of Patent Document 1 is
(I) The distance between the gaps between adjacent warp threads is larger than the distance between the gaps between adjacent weft threads, and the weft threads are not sufficiently gripped by the warp threads.
(Ii) Originally a thin glass cloth, the warp and weft are thin and flexible (iii) A low-mass glass cloth is impregnated with a resin solution so that the mass ratio of the glass cloth is low. When curing, the wefts are more easily moved in the width direction of the glass cloth due to curing shrinkage than when the glass cloth is impregnated with a resin solution so that the mass ratio of the glass cloth is relatively high.
In combination with these factors, we thought that the wefts would move slightly in the width direction of the glass cloth, and that vertical wrinkles would be more likely to occur.

In addition, the present inventor performs an excessive fiber-spreading treatment on the glass cloth of Patent Document 2, and in particular, each filament constituting the weft is bent, and vertical wrinkles are likely to occur due to this. I thought it would be. That is, when each filament constituting the weft is bent, each filament is present in the glass cloth in a loosened state. Then, the loose filament is in a state where it can easily move in the width direction of the glass cloth, and if a low-mass glass cloth is impregnated with a resin solution so that the mass ratio of the glass cloth is low and cured, the glass cloth is cured. It was considered that the wefts slightly moved in the width direction of the glass cloth due to the loosening of the filaments during the contraction, and the vertical wrinkles were likely to occur accordingly.

On the other hand, considering the above-mentioned mechanism of action, both suppression of pinhole generation and suppression of vertical wrinkle generation can be achieved by increasing the warp density and weft density of the glass cloth or by increasing the number of filaments in the warp and weft. It was also thought that it should be done. However, the present inventors increase the mass of the glass cloth and the mass of the prepreg when the warp density and the weft density of the glass cloth are increased or the number of filaments in the warp and the weft is increased. I learned that there is a problem of getting rid of it. Further, if the mass ratio of the glass cloth is too high in the prepreg, the glass cloth is exposed from the surface of the prepreg, and the signal layer and the exposed glass cloth are in direct contact with each other, which impairs the insulation reliability. I also learned.

Further, the present inventors have increased the warp density and the weft density of the glass cloth as the glass cloth becomes thinner, increased the number of filaments in the warp and the weft, and performed excessive fiber opening treatment. It was also found that when the gap space surrounded by the adjacent warp and weft threads becomes extremely small, the glass cloth tends to be internally distorted and vertical wrinkles are likely to occur.

Therefore, as a result of diligent studies by the present inventor in order to solve the above problems, the gap design values between the warp threads and the weft threads calculated from the filament diameter, the number of filaments and the weaving density of the warp threads and the weft threads before the fiber opening treatment are obtained. , Designed to be less than or equal to a specific value so as not to require excessive fiber opening, and between adjacent warp threads after fiber opening treatment in order to sufficiently grip the warp and weft while keeping the glass cloth mass below the specific mass. The ratio of the measured gap value and the measured gap between adjacent wefts is within the specified range, and the area ratio of the basket hole (opening portion) formed by the adjacent warp and adjacent weft is set within the specified range. By performing the fiber opening treatment in this manner, when a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg, the occurrence of pinholes is suppressed and the above-mentioned vertical wrinkles are suppressed. It was found that it is possible to achieve both suppression of occurrence. The present invention has been completed by further studies based on such findings.

That is, the present invention provides the inventions of the following aspects.
Item 1. A glass cloth having a mass of 10 g / m ² or less, the gap design value Iwd between adjacent warp threads represented by the following formula (1) of the glass cloth is 95 μm or less, and adjacent weft threads represented by the following formula (2). The gap design value Ifd between them is 95 μm or less, and the ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads of the glass cloth is 1. .10 or more and 1.60 or less, and the basket hole area ratio of the glass cloth represented by the following formula (3) is 12% or more and 20% or less.
Gap design value between adjacent warp threads Iwd (μm) = (25000 / Ww)-(Dw × Nw) ・ ・ ・ Equation (1)
Gap design value between adjacent wefts Ifd (μm) = (25000 / Wf)-(Df × Nf) ・ ・ ・ Equation (2)
Basket hole area ratio (%) = (Iw × If) / {(25000 / Ww) × (25000 / Wf)} × 100 ・ ・ ・ Equation (3)
Ww: Warp density of glass cloth (book / 25 mm)
Wf: Weft density of glass cloth (book / 25 mm)
Dw: Average filament diameter (μm) of the warp threads constituting the glass cloth
Df: Average filament diameter (μm) of the wefts constituting the glass cloth
Nw: Average number of warp filaments (filament) that make up the glass cloth
Nf: Average number of filaments of wefts constituting the glass cloth (threads)
Iw: Measured value of gap between adjacent warp threads in glass cloth (μm)
If: Measured value of gap between adjacent wefts in glass cloth (μm)
Item 2. The gap design value Iwd between the adjacent warp threads is 70 μm or more and 95 μm or less, and the gap design value Ifd between the adjacent weft threads is 70 μm or more and 95 μm or less, and the gap measured value (Iw) between the adjacent warp threads of the glass cloth. ) And the measured value (If) of the gap between the adjacent weft threads (Iw / If) is 1.25 or more and 1.45 or less, and the basket hole area ratio of the glass cloth is 12% or more and 18% or less. , Item 1. The glass cloth.
Item 3. A prepreg comprising a glass cloth according to claim 1 or 2, wherein the prepreg mass (g / m ²⁾ the glass cloth of the mass with respect to the proportion of (g / m ²⁾ (mass of glass cloth weight / prepreg) Is 10-40% by mass, prepreg.
Item 4. A method for producing a glass cloth having a mass of 10 g / m ² or less, wherein the gap design value Iwd between adjacent warp threads represented by the following formula (1) of the glass cloth is 95 μm or less, and the following formula (2) is shown. While the gap design value Ifd between adjacent wefts is 95 μm or less, the ratio (Iw / If) of the glass cloth between the measured gap between adjacent warp threads (Iw) and the measured gap between adjacent weft threads (If). ) Is 1.10 or more and 1.60 or less, and the fiber opening treatment is performed so that the basket hole area ratio of the glass cloth represented by the following formula (3) is 12% or more and 20% or less. How to manufacture glass cloth.
Gap design value between adjacent warp threads Iwd (μm) = (25000 / Ww)-(Dw × Nw) ・ ・ ・ Equation (1)
Gap design value between adjacent wefts Ifd (μm) = (25000 / Wf)-(Df × Nf) ・ ・ ・ Equation (2)
Basket hole area ratio (%) = (Iw × If) / {(25000 / Ww) × (25000 / Wf)} × 100 ・ ・ ・ Equation (3)
Ww: Warp density of glass cloth (book / 25 mm)
Wf: Weft density of glass cloth (book / 25 mm)
Dw: Average filament diameter (μm) of the warp threads constituting the glass cloth
Df: Average filament diameter (μm) of the wefts constituting the glass cloth
Nw: Average number of warp filaments (filament) that make up the glass cloth
Nf: Average number of filaments of wefts constituting the glass cloth (threads)
Iw: Measured value of gap between adjacent warp threads in glass cloth (μm)
If: Measured value of gap between adjacent wefts in glass cloth (μm)

According to the glass cloth of the present invention, the glass cloth having a mass of 10 g / m ² or less has a gap design value Iwd between adjacent warp threads of 95 μm or less and a gap design value Ifd between adjacent weft threads of 95 μm. The ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads is 1.10 or more and 1.60 or less, and the basket hole area ratio is 12. Since it is% or more and 20% or less, when a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg, pinhole generation is suppressed and the above-mentioned vertical wrinkles are suppressed. It is possible to achieve both suppression of occurrence.

Hereinafter, the present invention will be described in detail.

The glass cloth of the present invention is a glass cloth having a mass of 10 g / m ² or less, and the gap design value Iwd between adjacent warp threads represented by the following formula (1) of the glass cloth is 95 μm or less, and the following formula ( The gap design value Ifd between adjacent wefts shown in 2) is 95 μm or less, and the ratio of the measured gap between adjacent warp threads (Iw) and the measured gap between adjacent wefts (If) of the glass cloth. (Iw / If) is 1.10 or more and 1.60 or less, and the basket hole area ratio of the glass cloth represented by the following formula (3) is 12% or more and 20% or less.
Gap design value between adjacent warp threads Iwd (μm) = (25000 / Ww)-(Dw × Nw) ・ ・ ・ Equation (1)
Gap design value between adjacent wefts Ifd (μm) = (25000 / Wf)-(Df × Nf) ・ ・ ・ Equation (2)
Basket hole area ratio (%) = (Iw × If) / {(25000 / Ww) × (25000 / Wf)} × 100 ... Equation (3)
Ww: Warp density of glass cloth (book / 25 mm)
Wf: Weft density of glass cloth (book / 25 mm)
Dw: Average filament diameter (μm) of the warp threads constituting the glass cloth
Df: Average filament diameter (μm) of the wefts constituting the glass cloth
Nw: Average number of warp filaments (filament) that make up the glass cloth
Nf: Average number of filaments of wefts constituting the glass cloth (threads)
Iw: Measured value of gap between adjacent warp threads in glass cloth (μm)
If: Measured value of gap between adjacent wefts in glass cloth (μm)

Glass cloth of the present invention, the mass is less 10 g / ^{m 2,} preferably from 9.5 g / ^{m 2} or less, more preferably 9.0 g / ^{m 2.} The lower limit of the above mass range is not particularly limited, but for example, 5.0 g / m ² or more is preferable, 6.0 g / m ² or more is more preferable, 7.0 g / m ² or more is more preferable, and 8. 0 g / m ² or more is more preferable. In the present invention, the mass is measured and calculated according to JIS R 3420: 2103 7.2.

In the glass cloth of the present invention, the gap design value Iwd between adjacent warp threads represented by the following formula (1) is 95 μm or less, and the gap design value Ifd between adjacent weft threads represented by the following formula (2) is 95 μm or less. The lower limit of the gap design value between the warp threads and the gap design value between the weft threads is not particularly limited, but 60 μm from the viewpoint of making it easier to achieve both the suppression of pinhole occurrence and the suppression of vertical wrinkle generation. The above is preferable, 70 μm or more is more preferable, and 85 μm or more is further preferable.

Gap design value between adjacent warp threads Iwd (μm) = (25000 / Ww)-(Dw × Nw) ・ ・ ・ Equation (1)
Gap design value between adjacent wefts Ifd (μm) = (25000 / Wf)-(Df × Nf) ・ ・ ・ Equation (2)
Ww: Warp density of glass cloth (book / 25 mm)
Wf: Weft density of glass cloth (book / 25 mm)
Dw: Average filament diameter (μm) of the warp threads constituting the glass cloth
Df: Average filament diameter (μm) of the wefts constituting the glass cloth
Nw: Average number of warp filaments (filament) that make up the glass cloth
Nf: Average number of filaments of wefts constituting the glass cloth (threads)

The gap design value of the warp yarn and the gap design value of the weft yarn are obtained by first, in the warp yarn and the weft yarn (glass yarn) composed of a plurality of filaments, all the filaments constituting the glass yarn are arranged in a row without a gap in the glass yarn width direction. Virtually placed. At this time, in the virtual, the width (μm) of the virtual glass yarn can be calculated by multiplying the average filament diameter by the average number of filaments (that is, Dw × Nw in the case of warp yarns). Next, since the weaving density (warp density is Ww and weft density is Wf) is the number of glass threads between 25 mm (25,000 μm) as described later, 25,000 μm is divided by the weave density (25,000 / Ww in the case of warp threads). ) Therefore, the sum of the width of the glass threads and the gap spacing between the adjacent glass threads can be calculated. Then, by subtracting the virtual glass thread width from the sum of the widths of the glass threads and the adjacent glass threads, the gap spacing between the virtual adjacent warp threads and the virtual adjacent warp threads in the virtual state are obtained. The gap spacing can be calculated, and these are used as the gap design value between adjacent warp yarns and the gap design value between adjacent weft yarns, respectively.

The present inventor has designed the glass cloth given as a specific example in Patent Document 2 so that the gap design value of the warp and the gap design value of the weft exceed 100 μm, which is excessive. A method is adopted in which the gap is reduced by the fiber opening treatment. In this method, each filament is present in the glass cloth in a loosened state, and due to this, each filament constituting the weft is particularly eye-catching. It caused bending, and it was thought that vertical wrinkles were likely to occur due to this. Then, the present inventor has found that the occurrence of vertical wrinkles and the suppression of pinholes can be achieved by setting the gap design value of the warp and the gap design value of the weft to a specific range or less.

In the glass cloth of the present invention, the warp density Ww and the weft density Wf (25 mm) of the glass cloth are prepared by impregnating a low-mass glass cloth with a resin solution so that the mass ratio of the glass cloth is low. From the viewpoint of making it easier to achieve both the suppression of pinhole generation and the suppression of vertical wrinkle generation, 90 to 160 lines / 25 mm is preferable, 95 to 150 lines / 25 mm is more preferable, and 100 to 100 to 120 pieces / 25 mm is more preferable. In the present invention, the warp density and the weft density are measured and calculated according to JIS R 3420 2013 7.9.

In the glass cloth of the present invention, the average filament diameter Dw of the filaments constituting the warp threads (glass threads) constituting the glass cloth and the average filament diameter Df of the filaments constituting the weft threads (glass threads) are such that a low-mass glass cloth is used. 2. From the viewpoint of making it easier to achieve both suppression of pinhole generation and suppression of vertical wrinkle generation when impregnating a resin solution so that the mass ratio of the glass cloth is low to form a prepreg. It is preferably 5 to 4.0 μm, more preferably 3.0 to 3.7 μm.

In the glass cloth of the present invention, the average number of filaments Nw constituting the warp threads (glass threads) constituting the glass cloth and the average number of filaments Nf of the filaments constituting the weft threads (glass threads) are such that a low-mass glass cloth is used as the glass. When impregnating a resin solution so that the mass ratio of the cloth is low to form a prepreg, from the viewpoint of making it easier to achieve both suppression of pinhole generation and suppression of vertical wrinkle generation, 25 to 50 Books are preferred, and 30-40 are more preferred.

In the present invention, the average filament diameter (Dw and Df) and the average number of filaments (Nw and Nf) are measured and calculated as follows.

That is, two pieces of the obtained glass cloth cut into 30 cm squares are prepared, one for observing warp threads and the other for observing weft threads, and each is wrapped in epoxy resin (trade name 3091 manufactured by Marumoto Struas Co., Ltd.). It is buried and cured, polished to the extent that warp and weft can be observed, and observed using SEM (trade name JSM-6390A manufactured by JEOL Ltd.) with a filament diameter of 1000 times and a number of filaments of 500 times. , Make a measurement.
(1) Average filament diameter (μm) of glass thread
Thirty warp threads and weft threads are randomly selected, and the diameters (largest portions) of all filaments of the 30 glass threads are measured to calculate an average value, which is used as the average filament diameter of the warp threads and weft threads.
(2) Average number of filaments (filament)
Twenty warp threads and weft threads are randomly selected, and the total number of filaments of the 20 glass threads is measured to calculate the average value, which is used as the average filament diameter of the warp threads and the weft threads.

In the glass cloth of the present invention, the count (tex) of the warp and weft is not particularly limited, but a low-mass glass cloth is impregnated with a resin solution so that the mass ratio of the glass cloth is low, and the prepreg is used. From the viewpoint of making it easier to achieve both suppression of pinhole generation and suppression of vertical wrinkle generation, 0.5 to 1.2 tex is preferable, 0.6 to 1.1 tex is more preferable, and 0 .9 to 1.1 tex is more preferable. In the present invention, the counts of the warp and the weft are measured and calculated according to JIS R 3420 2013 7.1.

In the present invention, the glass material constituting the warp and weft is not particularly limited, and a known glass material can be used. Specific examples of the glass material include non-alkali glass (E glass), acid-resistant alkali-containing glass (C glass), high-strength and high-elasticity glass (S glass, T glass, UT glass (Unitica glass fiber stock). (Manufactured by the company), etc.), alkali resistant glass (AR glass), low dielectric glass (NE glass, L glass, LU glass (manufactured by Unitica Glass Fiber Co., Ltd.), etc.) and the like. Among these glass materials, preferably non-alkali glass (E glass) having high versatility can be mentioned. The glass fiber constituting the glass fiber cloth 2 may be made of one kind of glass material, or may be a combination of two or more kinds of glass fibers made of different glass materials.

In the glass cloth of the present invention, the ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads is 1.10 or more and 1.60 or less. It is more preferably 1.20 or more and 1.45 or less, and further preferably 1.30 or more and 1.40 or less. When the above ratio is 1.60 or less, the weft threads are sufficiently gripped by the warp threads, and when the low-mass glass cloth is impregnated with the resin solution and cured so that the mass ratio of the glass cloth is low. , It suppresses the weft from moving slightly in the width direction of the glass cloth, which makes it easier to prevent the occurrence of vertical wrinkles. Further, by setting the above ratio to 1.10 or more, the occurrence of pinholes is suppressed when the low-mass glass cloth is impregnated with the resin solution and cured so that the mass ratio of the glass cloth is low. It will be easier.

In the present invention, the measured gap value between adjacent warp threads and the measured gap value between adjacent weft threads are measured and calculated as follows. That is, first, in the glass cloth, the warp and weft threads are cut from three arbitrarily selected points to a size in which 100 consecutive gaps can be observed, and the sample is used as a sample. Next, the sample is observed and measured at a magnification of 150 times with a microscope. Specifically, from the normal direction of the glass cloth plane, the cross warp direction and the weft direction are observed at 100 continuous gap intervals on the same straight line. This is performed for the above-mentioned three arbitrarily selected points, and the warp and weft threads are measured at a total of 300 points, and the average value of the 300 points is used as the measured gap value.

In the glass cloth of the present invention, an actual measurement value (Iw) of a gap between adjacent warp threads is, for example, 70 to 120 μm, and a resin is used to reduce the mass ratio of the glass cloth to a low mass. When the solution is impregnated into a prepreg, 80 to 110 μm is more preferable, and 100 to 110 μm is further preferable, from the viewpoint of further suppressing the occurrence of pinholes and the above-mentioned vertical wrinkles. Further, in the glass cloth of the present invention, the measured gap value (If) between adjacent weft threads is, for example, 60 to 100 μm, so that the mass ratio of the low mass glass cloth is low. When the glass is impregnated with the resin solution to form a prepreg, 70 to 90 μm is more preferable, and 75 to 80 μm is further preferable, from the viewpoint of further suppressing the occurrence of pinholes and the above-mentioned vertical wrinkles.

In the glass cloth of the present invention, the ratio (Iw / Iwd) of the measured gap value (Iw) between adjacent warp threads to the gap design value Iwd (μm) between adjacent warp threads is, for example, 1.00 to 1. 30 is mentioned, and when a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg, the occurrence of pinholes and the suppression of vertical wrinkles are suppressed. From the viewpoint of further achieving both, 1.10 to 1.18 are preferably mentioned. Further, as the ratio (If / Ifd) of the gap measured value (If) between adjacent wefts to the gap design value Ifd (μm) between adjacent wefts, for example, 0.70 to 1.00 can be mentioned. When a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg, both suppression of pinhole generation and suppression of vertical wrinkle generation are further achieved. From the viewpoint, 0.80 to 1.00 is preferably mentioned.

In the glass cloth of the present invention, the basket hole area ratio represented by the following formula (3) is 12% or more and 20% or less, preferably 12% or more and 18% or less, and more preferably 14% or more and 17% or less.
Basket hole area ratio (%) = (Iw × If) / {(25000 / Ww) × (25000 / Wf)} × 100 ・ ・ ・ Equation (3)
Iw: Measured value of gap between adjacent warp threads (μm)
If: Measured value of gap between adjacent weft threads (μm)
Ww: Warp density of glass cloth (book / 25 mm)
Wf: Weft density of glass cloth (book / 25 mm)

In the glass cloth of the present invention, by setting the basket hole area ratio to 12% or more, internal distortion is less likely to occur in the glass cloth, and the low mass glass cloth is made of a resin so that the mass ratio of the glass cloth is low. Vertical wrinkles are less likely to occur when the solution is impregnated into a prepreg. Further, in the glass cloth of the present invention, when the basket hole area is 20% or less, a low mass glass cloth is impregnated with a resin solution so that the mass ratio of the glass cloth is low to form a prepreg. It becomes easier to suppress the occurrence of pinholes.

In the glass cloth of the present invention, the basket hole area is such that when a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg, the occurrence of pinholes is suppressed. From the viewpoint of further suppressing the occurrence of vertical wrinkles, for example, 3000 to 12000 μm ² is mentioned, 5000 to 9000 μm ² is more preferable, and 7500 to 8500 μm ² is further preferable. The basket hole area is calculated by multiplying the measured gap value Iw (μm) between adjacent warp threads and the measured gap value If (μm) between adjacent weft threads.

In the glass cloth of the present invention, as a basket hole area design value, pinholes are generated when a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg. From the viewpoint of further achieving both suppression and suppression of vertical wrinkle generation, for example, 3000 to 12000 μm ² is mentioned, 5000 to 9000 μm ² is more preferable, and 7500 to 8500 μm ² is further preferable. In the present invention, the baskethole area design value is calculated by multiplying the above-mentioned gap design value Iwd (μm) between adjacent warp threads and the gap design value Ifd (μm) between adjacent weft threads. is there.

In the glass cloth of the present invention, the ratio of the basket hole area to the above-mentioned basket hole area design value (basket hole area / basket hole area design value) is such that a low mass glass cloth has a low mass ratio of the glass cloth. From the viewpoint of further suppressing the occurrence of pinholes and the above-mentioned vertical wrinkles when impregnating the resin solution so as to form a prepreg, 0.8 to 1.2 can be mentioned. 9 to 1.1 are more preferable.

The thickness of the glass cloth of the present invention is, for example, preferably 12 μm or less, more preferably 11 μm or less. As the lower limit value, for example, 6 μm or more is mentioned, and 7 μm or more is preferably mentioned.

The weaving structure of the glass cloth is not particularly limited, and examples thereof include plain weave, satin weave, twill weave, diagonal weave, and ridge weave. Of these, plain weave is preferable. Further, the glass cloth of the present invention is preferably a glass cloth roll product. Examples of the length of the glass cloth roll product include 100 m or more.

Next, the method for producing the glass cloth of the present invention will be described.

The method for producing a glass cloth of the present invention is a method for producing a glass cloth having a mass of 10 g / m ² or less, and the gap design value Iwd between adjacent warp threads represented by the following formula (1) of the glass cloth is 95 μm. Below, while setting the gap design value Ifd between adjacent wefts shown in the following formula (2) to 95 μm or less, the measured gap between adjacent warp threads (Iw) and the measured gap between adjacent wefts of the glass cloth The ratio (Iw / If) to (If) is 1.10 or more and 1.60 or less, and the basket hole area ratio of the glass cloth represented by the following formula (3) is 12% or more and 20% or less. , Perform fiber opening treatment.
Gap design value between adjacent warp threads Iwd (μm) = (25000 / Ww)-(Dw × Nw) ・ ・ ・ Equation (1)
Gap design value between adjacent wefts Ifd (μm) = (25000 / Wf)-(Df × Nf) ・ ・ ・ Equation (2)
Basket hole area ratio (%) = (Iw × If) / {(25000 / Ww) × (25000 / Wf)} × 100 ・ ・ ・ Equation (3)
Ww: Warp density of glass cloth (book / 25 mm)
Wf: Weft density of glass cloth (book / 25 mm)
Dw: Average filament diameter (μm) of the warp threads constituting the glass cloth
Df: Average filament diameter (μm) of the wefts constituting the glass cloth
Nw: Average number of warp filaments (filament) that make up the glass cloth
Nf: Average number of filaments of wefts constituting the glass cloth (threads)
Iw: Measured value of gap between adjacent warp threads in glass cloth (μm)
If: Measured value of gap between adjacent wefts in glass cloth (μm)

As described above, the weaving density of the warp and weft that make up the glass cloth, the average diameter and the number of filaments that make up the warp and the weft are adjusted to design the gap between the adjacent warp and the gap design between the adjacent weft. As for the values, the ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads is 1.10 or more and 1.60 or less, and the basket hole. When a low-mass glass cloth is impregnated with a resin solution so that the mass ratio of the glass cloth is low by performing a fiber opening treatment so that the area ratio is 12% or more and 20% or less to form a prepreg. In addition, it is possible to achieve both suppression of pinhole generation and suppression of vertical wrinkle generation.

As a method for opening the fibers, for example, the obtained glass cloth is subjected to the opening treatment by the pressure of a water stream, and water (for example, degassed water, ion-exchanged water, deionized water, electrolytic cation water, electrolytic anion water, etc.). Examples thereof include fiber opening treatment by high-frequency vibration using the above as a medium, processing treatment by pressurization with a roll, and the like. Such opening treatment may be performed at the same time as weaving, or may be performed after weaving. It may be performed before or after heat cleaning described later or at the same time as heat cleaning, or may be performed at the same time as or after surface treatment described later. In addition, as a method for adjusting the degree of opening of the warp and weft, a known method can be adopted, a method for adjusting the warp tension, a pinch expander, a curved rubber roller, a rotary rotating roller, a Mirabo roller, or a method for adjusting the weft direction. Examples thereof include a method of adjusting and applying a tension balance between the warp and weft directions by adopting a method such as a tenter to open the fibers, or a method of combining these.

Among them, as a method of opening fibers, the pressure of water flow processing is set to 0.9 to 1.1 MPa, the tension in the warp direction (glass cloth length direction) is set to 18 to 22 N / m, and the weft is held by a tenter while being wefted. When the fiber opening treatment is performed by applying a tension of 5 to 10 N / m in the direction, the ratio of the measured gap between adjacent warp yarns (Iw) and the measured gap between adjacent weft yarns (If) is further increased. (Iw / If) is likely to be 1.10 or more and 1.60 or less, and the basket hole area ratio is 12% or more and 20% or less.

In the method for producing a glass cloth of the present invention, any conventionally known method may be adopted as a method for weaving the glass cloth. For example, after the warp threads are subjected to a warping step and a gluing step, a jet loom ( For example, an air jet loom, a water jet loom, etc.), a sulzer loom, a repeater loom, or the like is used to drive the weft into the weft.

When a substance that inhibits the adhesion and impregnation property of the resin used as a prepreg, such as a sizing agent, is attached to the woven glass cloth, it is preferable to remove the substance by, for example, a heat cleaning treatment. Further, it is preferable that the heat-cleaned glass cloth is surface-treated with a conventionally known silane coupling agent. Such a surface treatment means may be a conventionally known means, and examples thereof include a method of impregnating a glass cloth with a silane coupling agent, a method of coating, a method of spraying, and the like.

The prepreg of the present invention comprises a glass cloth of the present invention described above, (the weight of glass cloth weight / prepreg) ratio of the glass cloth of the mass relative to the mass (g / m ²⁾ of the prepreg (g / m ²⁾ Is 10 to 40% by mass, more preferably 20 to 30% by mass. Since the prepreg of the present invention contains the glass cloth of the present invention, even if the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) is within the above range, the occurrence of pinholes can be suppressed. , It is possible to achieve both the above-mentioned suppression of vertical wrinkles.

The prepreg of the present invention can contain a thermosetting resin and an inorganic filler other than the glass cloth in addition to the glass cloth.

The thermosetting resin is not particularly limited as long as it is a resin that can be cured by heat, but for example, a phenol resin, an epoxy resin, a non-halogen epoxy resin, a cyanate resin, a maleimide resin, a bismaleimide resin, a modified bismaleimide resin, or an isocyanate. Examples thereof include resins, benzocyclobutene resins, vinyl resins, bismaleimide triazine resins, phenol resins, thermosetting polyphenylene ether resins and the like. The thermosetting resin may be used alone or in combination of two or more.

Examples of the inorganic filler include silicas such as natural silica, molten silica, amorphous silica, and hollow silica; boehmite; molybdenum compounds such as molybdenum oxide and zinc molybdate; alumina, talc, calcined talc, mica, and short glass fibers. Glass fillers such as spherical glass (E glass, T glass, UT glass (manufactured by Unitika Glass Fiber Co., Ltd.), S glass, D glass, NE glass, L glass, LU glass (manufactured by Unitika Glass Fiber Co., Ltd.), etc. are used as glass materials. Glass filler) and the like.

The average particle size (D50) of the inorganic filler is not particularly limited, but is preferably 10 nm to 5.0 μm, more preferably 100 nm to 100 nm, from the viewpoint of use in thin multilayer printed wiring board applications and dispersibility. 2.0 μm, more preferably 100 nm to 1.0 μm. Here, the average particle diameter (D50) means the median diameter, and is the diameter at which the large side and the small side when the particle size distribution of the measured powder is divided into two are equal amounts. More specifically, the average particle size (D50) is the total volume integrated from the small particles when the particle size distribution of the powder dispersed in the methyl ethyl ketone is measured by a laser diffraction / scattering type particle size distribution measuring device. It means the value when 50% of the product is reached.

The inorganic filler is preferably surface-treated with a surface treatment agent such as a silane coupling agent. The amount of the surface treatment agent adhered to 100% by mass of the inorganic filler (ignition loss) is 0.1 to 5.0% by mass, preferably 0.5 to 3.0% by mass, and more preferably 0.5 to 3.0% by mass. It is 0.75 to 2.0% by mass.

The concentration of the non-volatile component of the resin solution (varnish) impregnated in the glass cloth is 50 to 100% by mass. Further, the varnish can be prepared so that the concentration of the above-mentioned inorganic filler in the non-volatile component is 30 to 60 vol%. In the prepreg of the present invention, the ratio (inorganic filler / thermosetting resin) of the mass (g / m ² ) of the inorganic filler to the mass (g / m ² ) of the thermosetting resin is, for example, 0.5. ~ 1.5 can be mentioned.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

(Example 1)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 40, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 105 / yarn. A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 105 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Example 1 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 94 μm, a gap design value Ifd between adjacent weft threads of 94 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.38, and the baskethole area ratio was 14.9%.

Next, two types of varnishes for obtaining prepreg were prepared.
<Varnish A>
Epoxy resin (jER5045B80 manufactured by Mitsubishi Chemical Corporation) 100 parts by mass Hardener (jER Cure DICY7 manufactured by Mitsubishi Chemical Corporation) 2.7 parts by mass (dicyandiamide)
Curing accelerator (2-ethyl-4-methylimidazole manufactured by Mitsubishi Chemical Corporation) 0.2 parts by mass Diluting solvent (dimethylformamide manufactured by Kishida Chemical Co., Ltd.) 20 parts by mass Inorganic filler (spherical glass, average particle diameter 0.5 μm) ) 25 parts by mass

<Varnish B>
<Varnish B>
Modified bismaleimide resin (HR3070 manufactured by Printec Co., Ltd.) 60 parts by mass Curing accelerator (2-ethyl-4-methylimidazole manufactured by Mitsubishi Chemical Corporation) 0.3 parts by mass Diluting solvent (methyl ethyl ketone manufactured by Kishida Chemical Co., Ltd.) 40 parts by mass Part Inorganic filler (spherical glass, average particle diameter 0.5 μm) 25 parts by mass

The glass cloth roll product of Example 1 was continuously fed out in the longitudinal direction (transverse direction), sufficiently immersed in the varnish A, and the varnish A was applied to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, and the prepregrol product A of Example 1 was obtained by continuously winding the varnish A through a dryer so that the gel time indicating the degree of curing of the resin was about 110 seconds.

Further, the glass cloth roll product of Example 1 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish B adhered was adjusted, and the varnish B was passed through a dryer so that the gel time was about 110 seconds and wound as it was to obtain the prepregrol product B of Example 1.

(Example 2)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 40, and a twist number of 0.5Z is woven by an air jet loom, and the warp density is 110 threads / A glass cloth roll having a width of 130 cm and a plain weave of 25 mm and a weft density of 110 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Example 2 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 83 μm, a gap design value Ifd between adjacent weft threads of 83 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.51 and the basket hole area ratio was 16.0%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Example 2 was continuously fed out in the longitudinal direction (longitudinal direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, and the varnish A was passed through a dryer so that the gel time was about 110 seconds and wound as it was to obtain the prepregrol product A of Example 2.

Further, the glass cloth roll product of Example 2 was continuously fed in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish B adhered was adjusted, and the varnish was passed through a dryer so that the gel time was about 110 seconds and wound as it was to obtain the prepregrol product B of Example 2.

(Example 3)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 36, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 115 / yarn. A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 115 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Example 3 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 88 μm, a gap design value Ifd between adjacent weft threads of 88 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.34, and the baskethole area ratio was 16.4%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Example 3 was continuously fed out in the longitudinal direction (longitudinal direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, and the varnish A was passed through a dryer so that the gel time was about 110 seconds and wound as it was to obtain the prepregrol product A of Example 3.

Further, the glass cloth roll product of Example 3 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish B adhered was adjusted, and the mixture was passed through a dryer so that the gel time was about 110 seconds and wound as it was to obtain the prepregrol product B of Example 3.

(Example 4)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 36, and a twist of 0.5Z is used and woven by an air jet loom, and the warp density is 125 threads / A glass cloth roll having a width of 130 cm and a plain weave of 25 mm and a weft density of 125 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Example 4 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 70 μm, a gap design value Ifd between adjacent weft threads of 70 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.53, and the basket hole area ratio was 13.3%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Example 4 was continuously fed out in the longitudinal direction (longitudinal direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time indicating the degree of curing of the resin was about 110 seconds, and the varnish A was passed through a dryer and wound as it was to obtain the prepregrol product A of Example 4. It was.

Further, the glass cloth roll product of Example 4 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish B adhered was adjusted, the drying conditions were adjusted so that the gel time, which indicates the degree of curing of the resin, was around 110 seconds, and the varnish was passed through a dryer and wound as it was to obtain the prepregrol product B of Example 4. It was.

(Example 5)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.3 μm, an average number of filaments of 35, and a twist number of 0.5Z is woven by an air jet loom, and the warp density is 125 threads / A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 125 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Example 5 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 85 μm, a gap design value Ifd between adjacent weft threads of 85 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.20, and the baskethole area ratio was 19.2%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Example 5 was continuously fed out in the longitudinal direction (longitudinal direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time indicating the degree of curing of the resin was about 110 seconds, and the varnish A was passed through a dryer and wound as it was to obtain the prepregrol product A of Example 5. It was.

Further, the glass cloth roll product of Example 5 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish B adhered was adjusted, the drying conditions were adjusted so that the gel time, which is an index of the degree of curing of the resin, was around 110 seconds, and the prepreg roll product B of Example 5 was obtained by passing it through a dryer and winding it as it was. It was.

(Example 6)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.1 μm, an average number of filaments of 34, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 135 /. A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 135 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.5 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Example 6 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 80 μm, a gap design value Ifd between adjacent weft threads of 80 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.29, and the baskethole area ratio was 18.4%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Example 6 was continuously fed out in the longitudinal direction (longitudinal direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time indicating the degree of curing of the resin was about 110 seconds, and the varnish A was passed through a dryer and wound as it was to obtain the prepregrol product A of Example 6. It was.

Further, the glass cloth roll product of Example 6 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish B adhered was adjusted, the drying conditions were adjusted so that the gel time indicating the degree of curing of the resin was about 110 seconds, and the varnish was passed through a dryer and wound as it was to obtain the prepregrol product B of Example 6. It was.

(Example 7)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.1 μm, an average number of filaments of 32, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 145 yarns / yarn. A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 145 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) JNC Corporation) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Example 6 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 73 μm, a gap design value Ifd between adjacent weft threads of 73 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.19, and the baskethole area ratio was 19.5%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Example 7 was continuously fed out in the longitudinal direction (longitudinal direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time indicating the degree of curing of the resin was about 110 seconds, and the varnish A was passed through a dryer and wound as it was to obtain the prepregrol product A of Example 7. It was.

Further, the glass cloth roll product of Example 7 was continuously fed in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish B adhered was adjusted, the drying conditions were adjusted so that the gel time, which is an index of the degree of curing of the resin, was around 110 seconds, and the prepregrol product B of Example 7 was obtained by passing it through a dryer and winding it as it was. It was.

(Comparative Example 1)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 40, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 105 / yarn. A glass cloth roll having a width of 130 cm in a plain weave having a weft density of 105 threads / 25 mm was obtained at 25 mm. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 0.5 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Comparative Example 1 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 94 μm, a gap design value Ifd between adjacent weft threads of 94 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.35, and the basket hole area ratio was 21.5%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 1 was continuously fed out in the longitudinal direction (transverse direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish A attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product A of Comparative Example 1. It was.

Further, the glass cloth roll product of Comparative Example 1 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 1. It was.

(Comparative Example 2)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 40, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 105 / yarn. A glass cloth roll having a width of 130 cm in a plain weave having a weft density of 105 threads / 25 mm was obtained at 25 mm. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 50 N / m in the warp direction by water flow processing at a pressure of 1.2 MPa, a tension of 20 to 25 N / m is applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Comparative Example 2 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 94 μm, a gap design value Ifd between adjacent weft threads of 94 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.00, and the basket hole area ratio was 18.7%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 2 was continuously fed out in the longitudinal direction (transverse direction), sufficiently immersed in the varnish A, and the varnish A was applied to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish A attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product A of Comparative Example 2. It was.

Further, the glass cloth roll product of Comparative Example 2 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 2. It was.

(Comparative Example 3)
As the warp and weft, the glass material is E glass, and a glass thread having an average filament diameter of 3.6 μm, an average number of filaments of 40, and a twist number of 0.5Z is woven by an air jet loom, and the warp density is 125 threads / A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 125 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa, a tension of 15 to 20 N / m is applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Comparative Example 3 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 56 μm, a gap design value Ifd between adjacent weft threads of 56 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.25, and the baskethole area ratio was 9.8%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 3 was continuously fed out in the longitudinal direction (transverse direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time, which indicates the degree of curing of the resin, was around 110 seconds, and the varnish A was passed through a dryer and wound as it was to obtain the prepregrol product A of Comparative Example 3. It was.

Further, the glass cloth roll product of Comparative Example 3 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 3. It was.

(Comparative Example 4)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 40, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 105 / yarn. A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 105 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, the same procedure as in Example 1 was carried out except that the tension of the glass cloth was set to 50 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa and the fiber opening treatment was performed without applying tension in the weft direction. The glass cloth roll product of Comparative Example 4 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 94 μm, a gap design value Ifd between adjacent weft threads of 94 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.64, and the basket hole area ratio was 17.6%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 4 was continuously fed out in the longitudinal direction (transverse direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time, which indicates the degree of curing of the resin, was around 110 seconds, and the varnish A was passed through a dryer and wound as it was to obtain the prepregrol product A of Comparative Example 4. It was.

Further, the glass cloth roll product of Comparative Example 4 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 4. It was.

(Comparative Example 5)
As the warp and weft, the glass material is E glass, and a glass thread having an average filament diameter of 3.6 μm, an average number of filaments of 40, and a twist number of 0.5Z is woven by an air jet loom, and the warp density is 100 threads / A glass cloth roll having a width of 130 cm and a plain weave of 25 mm and a weft density of 100 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.5 MPa, a tension of 15 to 20 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Comparative Example 5 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 106 μm, a gap design value Ifd between adjacent weft threads of 106 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.22, and the baskethole area ratio was 15.8%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 5 was continuously fed out in the longitudinal direction (transverse direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish A attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product A of Comparative Example 5. It was.

Further, the glass cloth roll product of Comparative Example 5 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 5. It was.

(Comparative Example 6)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 36, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 115 / yarn. A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 115 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 0.5 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Comparative Example 6 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 88 μm, a gap design value Ifd between adjacent weft threads of 88 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.34, and the basket hole area ratio was 21.5%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 6 was continuously fed out in the longitudinal direction (transverse direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time, which indicates the degree of curing of the resin, was around 110 seconds, and the varnish was passed through a dryer and wound as it was to obtain the prepregrol product A of Comparative Example 6. It was.

Further, the glass cloth roll product of Comparative Example 6 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 6. It was.

(Comparative Example 7)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 36, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 110 threads / A glass cloth roll having a width of 130 cm and a plain weave of 25 mm and a weft density of 110 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 1.0 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Comparative Example 7 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 98 μm, a gap design value Ifd between adjacent weft threads of 98 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.29, and the baskethole area ratio was 18.9%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 7 was continuously fed out in the longitudinal direction (transverse direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time, which indicates the degree of curing of the resin, was around 110 seconds, and the varnish was passed through a dryer and wound as it was to obtain the prepregrol product A of Comparative Example 7. It was.

Further, the glass cloth roll product of Comparative Example 7 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 7. It was.

(Comparative Example 8)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 36, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 115 / yarn. A glass cloth roll having a width of 130 cm in a plain weave having a width of 25 mm and a weft density of 115 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, the same procedure as in Example 1 was carried out except that the tension of the glass cloth was set to 50 N / m in the warp direction by water flow processing at a pressure of 0.5 MPa and the fiber opening treatment was performed without applying tension in the weft direction. The glass cloth roll product of Comparative Example 8 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 88 μm, a gap design value Ifd between adjacent weft threads of 88 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.70, and the baskethole area ratio was 17.1%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 1 was continuously fed out in the longitudinal direction (transverse direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish A attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product A of Comparative Example 1. It was.

Further, the glass cloth roll product of Comparative Example 1 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 1. It was.

(Comparative Example 9)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 36, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 130 threads / A glass cloth roll having a width of 130 cm in a plain weave having a weft density of 130 threads / 25 mm was obtained at 25 mm. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 50 N / m in the warp direction by water flow processing at a pressure of 1.5 MPa, a tension of 20 to 25 N / m is applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Comparative Example 9 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 63 μm, a gap design value Ifd between adjacent weft threads of 63 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.50, and the basket hole area ratio was 8.6%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 9 was continuously fed out in the longitudinal direction (transverse direction), sufficiently immersed in the varnish A, and the varnish A was applied to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. The amount of varnish A adhered was adjusted, the drying conditions were adjusted so that the gel time, which indicates the degree of curing of the resin, was around 110 seconds, and the varnish A was passed through a dryer and wound as it was to obtain the prepregrol product A of Comparative Example 9. It was.

Further, the glass cloth roll product of Comparative Example 9 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 9. It was.

(Comparative Example 10)
As the warp and weft, the glass material is E glass, and glass yarn having an average filament diameter of 3.6 μm, an average number of filaments of 38, and a twist of 0.5Z is woven by an air jet loom, and the warp density is 105 / yarn. A glass cloth roll having a width of 130 cm and a plain weave of 25 mm and a weft density of 110 threads / 25 mm was obtained. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass cloth were removed by heating at 400 ° C. for 30 hours. Then, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Co., Ltd.) was adjusted to a concentration of 10 g / L and squeezed with a padder roll. After that, it was dried and cured at 120 ° C. for 1 minute. Then, while the tension of the glass cloth is set to 20 N / m in the warp direction by water flow processing at a pressure of 0.8 MPa, a tension of 5 to 10 N / m is also applied in the weft direction while grasping both ends of the glass cloth in the weft direction with a tenter. The fiber was opened and the glass cloth roll product of Comparative Example 10 was obtained. The obtained glass cloth has a gap design value Iwd between adjacent warp threads of 101 μm, a gap design value Ifd between adjacent weft threads of 90 μm, and a gap measurement value (Iw) between adjacent warp threads and a gap measurement between adjacent weft threads. The ratio to the value (If) was 1.33, and the baskethole area ratio was 21.7%.

Next, as the varnish for obtaining the prepreg, varnish A and varnish B were prepared as in Example 1.

The glass cloth roll product of Comparative Example 10 was continuously fed out in the longitudinal direction (transverse direction) and sufficiently immersed in the varnish A to apply the varnish A to the glass cloth. Subsequently, the glass cloth coated with the varnish A was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish A attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product A of Comparative Example 10. It was.

Further, the glass cloth roll product of Comparative Example 10 was continuously fed out in the longitudinal direction (transverse direction), and this time, the glass cloth was sufficiently immersed in the varnish B to apply the varnish B to the glass cloth. Subsequently, the glass cloth coated with the varnish B was subjected to a gap roll so that the ratio of the mass of the glass cloth (g / m ² ) to the mass of the prepreg (g / m ² ) was as shown in Table 1. Adjust the amount of varnish B attached, adjust the drying conditions so that the gel time, which is an index of the degree of curing of the resin, is around 110 seconds, pass it through a dryer, and wind it as it is to obtain the prepregrol product B of Comparative Example 10. It was.

Measurements and evaluations in Examples and Comparative Examples were carried out by the following methods.

1. 1. Average filament diameter Dw and Df (μm), average number of filaments Nw and Nf (lines)
This was done by the method described above.

2. 2. Count (tex)
This was done by the method described above.

3. 3. Weaving density Ww and Wf (book / 25mm)
This was done by the method described above.

4. Measured gap between adjacent warp threads Iw and measured gap between adjacent weft threads If (μm)
This was done by the method described above.

5. Mass (g / m ² ) and thickness (μm) of glass cloth
The mass of the glass cloth was measured and calculated according to JIS R 3420 2013 7.2. The thickness of the glass cloth was measured and calculated according to the JIS R 3420 2013 7.10.1A method.

6. Evaluation of pinhole generation Three prepregs cut into a 400 mm x 400 mm quadrangle from the obtained prepreg roll product were collected from any location in the width direction, and 50 sets were arbitrarily set in the length direction (150 sheets in total). The number of pinholes was visually counted for each of the 150 prepregs, and the prepregs having 4 or less were regarded as non-defective products, and the non-defective product rate out of 150 sheets was evaluated. Those with a non-defective rate of 90% or more were accepted.

7. Evaluation of vertical wrinkles The number of vertical wrinkles was observed by visually inspecting each of the obtained prepregrol products A and B at a length of 100 m at random, and the number of vertical wrinkles per 100 m in length was evaluated according to the following criteria. The vertical wrinkles were counted to have a length of 10 cm or more.
◯: The occurrence of vertical wrinkles was 0 to 2/100 m.
Δ: The number of vertical wrinkles was 3 to 5/100 m.
X: The number of vertical wrinkles exceeded 5/100 m.

Tables 1 and 2 show the physical characteristics of Examples and Comparative Examples.

The glass cloths of Examples 1 to 7 are glass cloths having a mass of 10 g / m ² or less, and the gap design value Iwd between adjacent warp threads of the glass cloth is 95 μm or less, and the gap design between adjacent weft threads. The value Ifd is 95 μm or less, and the ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads of the glass cloth is 1.10 or more and 1 Since it is .60 or less and the basket hole area ratio of the glass cloth represented by the following formula (3) is 12% or more and 20% or less, the low mass glass cloth is considered to have a low mass ratio of the glass cloth. When impregnating the resin solution so as to form a prepreg, it has become possible to suppress the occurrence of pinholes and the above-mentioned vertical wrinkles at the same time.

Among them, in the glass cloths of Examples 1 and 3, the gap design value Iwd between the adjacent warp threads is 70 μm or more and 95 μm or less, and the gap design value Ifd between the adjacent weft threads is 70 μm or more and 95 μm or less, and the glass cloth. The ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads is 1.25 or more and 1.45 or less, and the glass cloth of the said glass cloth. Since the basket hole area ratio represented by the following formula (3) is 12% or more and 18% or less, a low-mass glass cloth is impregnated with a resin solution so that the mass ratio of the glass cloth is low to form a prepreg. At the same time, it has become possible to further suppress the occurrence of pinholes and the above-mentioned vertical wrinkles.

On the other hand, in Comparative Example 1, since the basket hole area ratio exceeded 20%, a low-mass glass cloth was impregnated with a resin solution so that the mass ratio of the glass cloth was low, and the prepreg was used. At that time, it was difficult to suppress the occurrence of pinholes.

In Comparative Example 2, since the ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads was less than 1.10, the mass was low. When the glass cloth is impregnated with the resin solution and cured so that the mass ratio of the glass cloth is low, it is difficult to suppress the occurrence of pinholes.

In Comparative Example 3, since the basket hole area ratio is less than 12%, internal strain is likely to occur in the glass cloth, and the low-mass glass cloth is impregnated with the resin solution so that the mass ratio of the glass cloth is low. It was difficult to suppress the occurrence of vertical wrinkles when the prepreg was used. Further, in Comparative Example 3, the mass of the glass cloth exceeded 10 g / m ² .

In Comparative Example 4, the ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads exceeded 1.60. The weft is slightly moved in the width direction of the glass cloth when the low-mass glass cloth is impregnated with the resin solution and cured so that the mass ratio of the glass cloth is low. It became difficult to suppress the occurrence of vertical wrinkles due to this.

In Comparative Example 5, the gap design value Iwd between the adjacent warp threads and the gap design value Ifd between the adjacent weft threads exceed 95 μm, which are the measured gap value (Iw) between the adjacent warp threads and the adjacent weft threads. Since the fiber opening treatment was performed so that the ratio (Iw / If) to the measured gap value (If) between them was 1.10 or more and 1.60 or less, and the basket hole area ratio was 12% or more and 20% or less. Each filament was present in the glass cloth in a loosened state, and as a result, each filament constituting the weft was bent, and as a result, vertical wrinkles were likely to occur. ..

In Comparative Example 6, since the basket hole area ratio exceeded 20%, when a low-mass glass cloth was impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg. In addition, it was difficult to suppress the occurrence of pinholes.

In Comparative Example 7, the gap design value Iwd between the adjacent warp threads and the gap design value Ifd between the adjacent weft threads exceed 95 μm, which are the measured gap value (Iw) between the adjacent warp threads and the adjacent weft threads. Since the fiber opening treatment was performed so that the ratio (Iw / If) to the measured gap value (If) between them was 1.10 or more and 1.60 or less, and the basket hole area ratio was 12% or more and 20% or less. Each filament was present in the glass cloth in a loosened state, and as a result, each filament constituting the weft was bent, and as a result, vertical wrinkles were likely to occur. ..

In Comparative Example 8, the ratio (Iw / If) of the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads exceeded 1.60. The weft is slightly moved in the width direction of the glass cloth when the low-mass glass cloth is impregnated with the resin solution and cured so that the mass ratio of the glass cloth is low. It became difficult to suppress the occurrence of vertical wrinkles due to this.

In Comparative Example 9, since the basket hole area ratio is less than 12%, internal distortion is likely to occur in the glass cloth, and the low-mass glass cloth is impregnated with the resin solution so that the mass ratio of the glass cloth is low. It was difficult to suppress the occurrence of vertical wrinkles when the prepreg was used.

In Comparative Example 10, the gap design value Iwd between adjacent warp threads exceeds 95 μm, and the fiber opening treatment is performed under relatively mild conditions, so that the basket hole area ratio exceeds 20%. When a low-mass glass cloth is impregnated with a resin solution so as to have a low mass ratio of the glass cloth to form a prepreg, it is difficult to suppress the occurrence of pinholes.

Claims (3)

A glass cloth with a mass of 10 g / m ² or less.
When the gap design value Iwd between adjacent warp yarns represented by the following formula (1) of the glass cloth is 70 μm or more and 95 μm or less, and the gap design value Ifd between adjacent weft yarns represented by the following formula (2) is 70 μm or more and 95 μm or less. Yes,
The ratio (Iw / If) of the glass cloth to the measured gap value (Iw) between adjacent warp threads and the measured gap value (If) between adjacent weft threads is 1.25 or more and 1.45 or less.
A glass cloth having a basket hole area ratio of 12% or more and 18 % or less represented by the following formula (3).

Gap design value between adjacent warp threads Iwd (μm) = (25000 / Ww)-(Dw × Nw) ・ ・ ・ Equation (1)
Gap design value between adjacent wefts Ifd (μm) = (25000 / Wf)-(Df × Nf) ・ ・ ・ Equation (2)
Basket hole area ratio (%) = (Iw × If) / {(25000 / Ww) × (25000 / Wf)} × 100 ・ ・ ・ Equation (3)

Ww: Warp density of glass cloth (book / 25 mm)
Wf: Weft density of glass cloth (book / 25 mm)
Dw: Average filament diameter (μm) of the warp threads constituting the glass cloth
Df: Average filament diameter (μm) of the wefts constituting the glass cloth
Nw: Average number of warp filaments (filament) that make up the glass cloth
Nf: Average number of filaments of wefts constituting the glass cloth (threads)
Iw: Measured value of gap between adjacent warp threads in glass cloth (μm)
If: Measured value of gap between adjacent wefts in glass cloth (μm) A prepreg containing the glass cloth according to claim 1 .
The prepreg of the mass ratio of the glass cloth of the mass with respect to ^{(g / m 2) (g} / m 2) ( mass of the glass cloth mass / prepreg) is 10 to 40 wt%, the prepreg. A method for manufacturing a glass cloth having a mass of 10 g / m ² or less.
The gap design value Iwd between adjacent warp threads represented by the following formula (1) of the glass cloth is 70 μm or more and 95 μm or less, and the gap design value Ifd between adjacent weft threads represented by the following formula (2) is 70 μm or more and 95 μm or less. While
The ratio (Iw / If) of the gap measured value (Iw) between adjacent warp threads and the gap measured value (If) between adjacent weft threads of the glass cloth is 1.25 or more and 1.45 or less, and the glass. A method for producing a glass cloth, which comprises performing a fiber opening treatment so that the basket hole area ratio of the cloth represented by the following formula (3) is 12% or more and 18 % or less.
Gap design value between adjacent warp threads Iwd (μm) = (25000 / Ww)-(Dw × Nw) ・ ・ ・ Equation (1)
Gap design value between adjacent wefts Ifd (μm) = (25000 / Wf)-(Df × Nf) ・ ・ ・ Equation (2)
Basket hole area ratio (%) = (Iw × If) / {(25000 / Ww) × (25000 / Wf)} × 100 ・ ・ ・ Equation (3)

Ww: Warp density of glass cloth (book / 25 mm)
Wf: Weft density of glass cloth (book / 25 mm)
Dw: Average filament diameter (μm) of the warp threads constituting the glass cloth
Df: Average filament diameter (μm) of the wefts constituting the glass cloth
Nw: Average number of warp filaments (filament) that make up the glass cloth
Nf: Average number of filaments of wefts constituting the glass cloth (threads)
Iw: Measured value of gap between adjacent warp threads in glass cloth (μm)
If: Measured value of gap between adjacent wefts in glass cloth (μm)