JP2023100589A - Manufacturing method of glass cloth, glass cloth, glass yarn and screening method of glass yarn - Google Patents

Abstract

To provide a glass cloth having less quality variation, good quality and low dielectric property.SOLUTION: There is provided a manufacturing method of a glass cloth which is formed by weaving a glass yarn containing a plurality of glass filaments as warp and weft and has a thickness of 8 to 100 μm. As the weft, the glass yarn is used in which: a mass per unit length ranges from 0.5 to 30.0 tex; a density ranges from 1.8 g/cm3 or more and less than 2.5 g/cm3; and 99.96% or more of the glass yarn in the lengthwise direction, at 50 m measurement in the lengthwise direction, is equal to or less than a yarn bundle width A represented by the following formula (1) A(μm)=68×ln(x)+112, where x is tex of glass yarn, and has an average yarn bundle width, at 50 m measurement in the lengthwise direction, equal to or more than a lower limit C represented by the following formula (2) C(μm)=49.0×ln(x)+19.5, where x is tex of glass yarn.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for producing glass cloth, glass cloth, glass yarn, and a method for sorting glass yarn.

2. Description of the Related Art With the recent development of information communication society, data communication and/or signal processing have come to be performed in large capacity and at high speed, and the dielectric constant of printed wiring boards used in electronic devices has been reduced. Therefore, many low-dielectric glass cloths have been proposed as glass cloths constituting printed wiring boards.

For example, the low-dielectric glass cloth disclosed in Patent Document 1 contains a large amount of boron oxide (B ₂ O ₃ ) in the glass composition and, at the same time, dioxide A low dielectric constant is achieved by adjusting the compounding amounts of other components such as silicon (SiO ₂ ).

Further, Patent Documents 2 and 3 disclose a method for manufacturing a low-dielectric glass cloth having uniform quality, and for the purpose of providing a glass thread suitable for manufacturing a low-dielectric glass cloth, the width of the glass thread or the variation in the thread width, etc. is disclosed as a specific range.

Japanese Patent Publication No. 2010-508226 JP 2020-105683 A JP 2021-178764 A

The problem is that the low-dielectric glass cloth produced using low-dielectric glass yarn described in Patent Document 1 has a large variation in performance or quality compared to the conventionally used E-glass cloth. was there. There is also the problem that such variations in the performance or quality of the glass cloth affect the quality of prepregs, laminates for printed wiring boards, and the like obtained using the glass cloth.

In the glass cloth manufacturing method described in Patent Document 2, even if the weavability and fluff quality are greatly improved overall, the glass monofilament is cut and entangled in units of 1 to 10. There is a problem that coarse fluff exceeding mm may occur. In addition, in the method for manufacturing the glass cloth described in Patent Document 3, even if the fluff quality is improved under mild manufacturing conditions, increasing the production speed to ensure a stable supply to the market will increase the number of lengths. There is a problem that coarse fluff exceeding mm may occur. At present, there is a demand for suppressing the occurrence of such coarse fluff, which can be a fatal drawback in the use of printed wiring boards.

The present invention has been made in view of the above problems. That is, it is an object of the present invention to provide a glass cloth that has good quality with little variation in quality and a low dielectric. Another object of the present invention is to provide a glass thread, a method for sorting the glass thread, and a method for manufacturing the glass cloth, which can realize such a glass cloth.

As a result of intensive studies to solve the above problems, the present inventors found that the above problems can be solved by focusing on glass yarns having TEX, density, and yarn bundle width distributions within specific ranges. The discovery led to the completion of the present invention. One aspect of the present invention is listed below.
[1]
A method for producing a glass cloth having a thickness of 8 to 100 μm, comprising weaving glass yarns containing a plurality of glass filaments as warp yarns and weft yarns,
as the weft
The mass per unit length is 0.5 to 30.0 tex,
a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ ;
When measuring 50 m in the length direction, 99.96% or more in the length direction is the following formula (1):
A (μm)=68×ln(x)+112 (1)
x: glass thread tex
is equal to or less than the yarn bundle width A indicated by
The average yarn bundle width when measuring 50 m in the length direction is the following formula (2):
C (μm)=49.0×ln(x)+19.5 (2)
x: glass thread tex
A method for manufacturing a glass cloth using a glass thread that is equal to or higher than the lower limit value C indicated by.
[2]
as the weft
When measuring 50 m in the length direction, 98.00% or more in the length direction is the following formula (3):
B (μm)=75×ln(x)+80 (3)
x: glass thread tex
The method for producing a glass cloth according to [1], which uses glass yarn having a yarn bundle width B or less.
[3]
The method for producing a glass cloth according to [1] or [2], wherein the twist interval length of the glass yarn is 1.8 to 4.0 cm.
[4]
The glass having a silicon (Si) content of 40 to 60% by mass in terms of silicon dioxide (SiO ₂ ) and a boron (B) content of 15 to 40% by mass in terms of boron oxide (B ₂ O ₃ ). The method for producing a glass cloth according to any one of [1] to [3], wherein yarns are used as the wefts.
[5]
The method for producing a glass cloth according to [4], wherein the glass yarn having a B content of 20 to 40% by mass in terms of B ₂ O ₃ is used as the weft yarn.
[6]
The method for producing a glass cloth according to any one of [1] to [5], wherein the glass yarn having an elastic modulus of 50 to 70 GPa is used as the weft yarn.
[7]
The method for producing a glass cloth according to any one of [1] to [6], wherein the glass yarn having an elastic modulus of 50 to 63 GPa is used as the weft yarn.
[8]
The method for producing a glass cloth according to any one of [1] to [7], wherein the weft is woven at a weft speed of more than 350 and 1000 or less per minute.
[9]
A glass yarn used for the weft of glass cloth,
glass thread,
The mass per unit length is 0.5 to 30.0 tex,
a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ ;
When measuring 50 m in the length direction, 99.96% or more in the length direction is the following formula (1):
A (μm)=68×ln(x)+112 (1)
x: glass thread tex
is equal to or less than the yarn bundle width A indicated by
The average yarn bundle width when measuring 50 m in the length direction is the following formula (2):
C (μm)=49.0×ln(x)+19.5 (2)
x: glass thread tex
A glass thread that is equal to or higher than the lower limit value C indicated by.
[10]
glass thread,
When measuring 50 m in the length direction, 98.00% or more in the length direction is the following formula (3):
B (μm)=75×ln(x)+80 (3)
x: glass thread tex
The glass yarn according to [9], which is equal to or less than the yarn bundle width B shown in.
[11]
The glass yarn according to [9] or [10], wherein the twist interval length of the glass yarn is 1.8 to 4.0 cm.
[12]
The silicon (Si) content is 40 to 60% by mass in terms of silicon dioxide (SiO ₂ ), and the boron (B) content is 15 to 40% by mass in terms of boron oxide (B ₂ O ₃ ). [9] The glass yarn according to any one of [11].
[13]
The glass yarn according to [12], wherein the B content is 20 to 40% by mass in terms of B ₂ O ₃ .
[14]
The glass yarn according to any one of [9] to [13], which has an elastic modulus of 50 to 70 GPa.
[15]
The glass yarn according to any one of [9] to [14], which has an elastic modulus of 50 to 63 GPa or less.
[16]
The glass yarn according to any one of [9] to [15], which has a dielectric constant of 5.0 or less at a frequency of 10 GHz.
[17]
The glass yarn according to any one of [9] to [16], having a dielectric loss tangent of 0.0050 or less at a frequency of 10 GHz.
[18]
The glass yarn according to any one of [9] to [17], which is used for weaving glass cloth for use in high-speed communication infrastructure.
[19]
A glass cloth comprising the glass yarn according to any one of [9] to [18].
[20]
The glass cloth according to [19], which has a dielectric constant of 5.0 or less at a frequency of 10 GHz.
[21]
The glass cloth according to [19] or [20], which is used for high-speed communication infrastructure.
[22]
A glass yarn sorting method suitable for producing a glass cloth by weaving glass yarns as warp and weft,
As the weft,
The mass per unit length is 0.5 to 30.0 tex,
a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ ;
The following formula (1):
A (μm)=68×ln(x)+112 (1)
x: glass thread tex
is equal to or less than the yarn bundle width A indicated by
The average yarn bundle width when measuring 50 m in the length direction is the following formula (2):
C (μm)=49.0×ln(x)+19.5 (2)
x: glass thread tex
A method for sorting glass yarns, comprising a step of sorting glass yarns that are equal to or higher than the lower limit value C indicated by.

ADVANTAGE OF THE INVENTION According to this invention, the glass cloth which has little quality variation, has good quality, and can be made into low dielectric can be provided. Further, according to the present invention, it is possible to provide a glass yarn, a method for sorting glass yarn, and a method for manufacturing glass cloth, which can realize such a glass cloth.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail, but the present invention is not limited to this, and various modifications are possible without departing from the gist thereof. is.

In the present embodiment, the numerical range described using "-" includes the numerical values before and after "-" as lower and upper limits. Further, in the present embodiment, in the numerical ranges described in stages, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. can be done. Furthermore, in this embodiment, the upper limit or lower limit described in a certain numerical range can be replaced with the values shown in the examples. In this embodiment, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the function of the process is achieved.

[Glass thread]
The glass yarn according to the present embodiment is a glass yarn used for the weft of the glass cloth,
The above glass thread is
The mass per unit length is 0.5 to 30.0 tex,
a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ ;
When measuring 50 m in the length direction, 99.96% or more in the length direction is the following formula (1):
A (μm)=68×ln(x)+112 (1)
x: glass thread tex
is equal to or less than the yarn bundle width A indicated by
The average yarn bundle width when measuring 50 m in the length direction is the following formula (2):
C (μm)=49.0×ln(x)+19.5 (2)
x: glass thread tex
is greater than or equal to the lower limit value C indicated by
Here, the glass yarn includes a plurality of glass filaments, and the yarn bundle width A is uniquely determined according to TEX. In this specification, "tex" means the mass (gram unit) per 1000 m, and is a unit representing the fineness (thickness) of yarn.

As a result of studies by the present inventors, it has been found that the glass cloth manufactured using the low-dielectric glass yarn has variations in the quality of the glass cloth compared to the conventional E glass cloth, and the quality of the glass cloth is stable and high. has proven difficult to obtain. Of these, a detailed examination of the glass cloth of relatively inferior quality reveals that in the fiber bundle width distribution in the length direction of the glass fiber (especially the weft), the glass cloth manufactured from the glass fiber including the wide portion of the fiber bundle width , Many coarse fluff defects were observed. Coarse fluff defects include, for example, defects exceeding several millimeters in length (for example, defects exceeding 2 mm in length), such as glass monofilaments that are broken and tangled in units of 1 to 10.

This embodiment is selected from the viewpoint that the ratio of the wide portion of the yarn bundle in the length direction is small, and the distribution of the yarn bundle width is within a specific range that is uniquely determined according to TEX. It is based on the knowledge that the drawback can be reduced by using the glass yarn as the weft yarn.

That is, one form of the present embodiment is a glass yarn sorting method suitable for producing a glass cloth by weaving glass yarns as warp and weft,
as the weft
The mass per unit length is 0.5 to 30.0 tex,
a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ ;
When measuring 50 m in the length direction, 99.96% or more in the length direction is the yarn bundle width A or less, and
A method for sorting glass yarns, comprising a step of sorting glass yarns having an average yarn bundle width equal to or higher than the lower limit value C when measuring 50 m in the length direction.

The reason why the above effect is obtained is not bound by theory, but is presumed as follows. A glass yarn (weft) including even a local portion with a wide yarn bundle has a significantly increased resistance to air or interference with a loom member at the wide portion of the yarn bundle. Therefore, the weft yarn is swayed in the direction perpendicular to the conveying direction or turned (also referred to as "ballooning movement" or "balloon movement") during the period from unwinding from the bobbin to ejection. tend to be large. It is thought that filament breakage is more likely to occur if shear stress acts on the glass yarn due to rubbing when the weft yarn passes through a loom member such as a loop guide.

In addition, the weft yarn including even a local portion with a wide yarn bundle is greatly affected by the fluctuation of the unwinding tension when unwinding from the bobbin or the on/off of the air jet pressure that ejects the weft yarn, Tension fluctuations tend to increase during the transportation process. Therefore, it is considered that the deflection or ballooning movement during the above-mentioned weft conveying process tends to increase.

Furthermore, the glass yarn of the E-glass, which has been used so far, has a larger mass per unit length and a higher strength than the low-dielectric glass yarn, so that the weft yarn can be conveyed stably, and there is no interference with the loom members. The degree was also small, and the damage received when interfering was also limited. On the other hand, low-dielectric glass yarns, which are lighter and weaker in strength, tend to sway more due to tension fluctuations and the like when the weft yarn is transported, and interference with the loom members is likely to occur, and when it interferes with the loom members. can also take more damage. For this reason, it is considered that the occurrence of fiment breakage is likely to be facilitated. It is considered that these influences appeared as the quality of the woven glass cloth.

On the other hand, in the present embodiment, by using the glass yarn as the weft yarn, the loom member can be stably produced even when the glass yarn having a relatively low dielectric strength and a relatively light weight and low strength is used. It is possible to reduce the degree of interference with or the damage received at the time of interference. As a result, it is possible to suppress the generation of coarse fluff due to filament breakage in the yarn path, and to obtain a glass cloth of good quality and less variation in quality.

(Mass per unit length of glass thread)
The mass per unit length of the glass thread is 0.5 to 30.0 tex. It is preferably 0.7 to 25.0 tex, more preferably 0.9 to 25.0 tex, still more preferably 1.0 to 22.0 tex.

If the glass yarn has a mass per unit length equal to or higher than the above lower limit, the distribution of the yarn bundle width is set within a specific range uniquely determined according to TEX, so that the glass yarn can be used as a weft. , the transport trajectory of the weft can be stabilized. Thereby, a high-quality glass cloth can be stably obtained.

The transport trajectory of the weft yarn becomes more stable as the mass per unit length increases. On the other hand, when the mass per unit length increases, shear stress caused by rubbing against a loom member such as a loop guide tends to increase due to swinging of the glass yarn in the direction perpendicular to the conveying direction or ballooning movement. Therefore, the glass filament tends to be easily cut. If the glass yarn has a mass per unit length equal to or less than the above upper limit, the distribution of the yarn bundle width is set within a specific range uniquely determined according to TEX, so that when the glass yarn is used as a weft, Cutting of the glass filaments can be suppressed, and high-quality glass cloth can be stably obtained.

(Density of glass thread)
The glass thread has a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ . The lower limit is preferably 2.0 g/cm ³ or more, more preferably 2.1 g/cm ³ or more, still more preferably 2.2 g/cm ³ or more, and most preferably 2.25 g/cm ³ or more. is. The upper limit of the glass density is preferably less than 2.45 g/cm ³ , more preferably 2.4/cm ³ or less.

Even if the glass yarn has a density of less than 2.5 g/cm ³ , if the yarn bundle width distribution is outside the specific range that is uniquely determined according to TEX, the glass yarn is unwound from the bobbin. During the transportation process until the droplets are ejected, the vibration in the direction perpendicular to the transportation direction or the ballooning motion tends to increase. As a result, fluff defects are likely to occur due to interference with the loom members. However, by using a glass yarn with a density of less than 2.5 g / cm ³ and setting the distribution of the yarn bundle width within a specific range uniquely determined according to TEX, the weft conveying trajectory is stabilized. high-quality glass cloth can be stably obtained.

A glass yarn having a density of 1.8 g/cm ³ or more can stabilize the transport trajectory of the weft when the glass yarn is used as the weft. The density of the glass thread can be determined as the density of a 1 cm ³ block of glass.

(Distribution of yarn bundle width of glass yarn)
99.96% or more of the glass yarn used for the weft in this embodiment has the following formula (1) when measured in the length direction of 50 m:
A (μm)=68×ln(x)+112 (1)
x: glass thread tex
is less than or equal to the yarn bundle width A indicated by A preferable range of the yarn bundle width distribution is that 99.97% or more in the length direction is the yarn bundle width A or less, and a more preferable range is 99.98% or more in the length direction is the yarn bundle width A or less. A more preferable range is that 99.99% or more in the length direction is the yarn bundle width A or less, and the most preferable range is that 100% in the length direction is the yarn bundle width A or less. The yarn bundle width A is the width of the glass yarn bundle uniquely determined according to the mass (tex) per unit length of the glass yarn. In this embodiment, the preferred range of the yarn bundle width distribution is that 100% or less in the length direction may be the yarn bundle width A or less.

Here, 98.00% or more of the glass yarn in the length direction when measured in the length direction of 50 m is the following formula (3):
B (μm)=75×ln(x)+80 (3)
x: glass thread tex
It is preferably less than or equal to the yarn bundle width B indicated by. More preferably, 98.5% or more in the length direction is the yarn bundle width B or less, and more preferably 99.0% or more in the length direction is the yarn bundle width B or less. Further, it is more preferable that 99.5% or more in the length direction is the yarn bundle width B or less, and it is most preferable that 100% or more in the length direction is the yarn bundle width B or less. The yarn bundle width B is the width of the glass yarn bundle uniquely determined according to the mass (tex) per unit length of the glass yarn.

In the yarn bundle width distribution in the length direction of the glass yarn, 99.96% or more is the yarn bundle width A or less, so that when using the glass yarn as a weft, the weft is ejected after being unwound from the bobbin. It is possible to suppress the occurrence of filament breakage in the transportation process to. As a result, it is possible to stably obtain a high-quality glass cloth with less fluff defects. This is considered as follows. That is, in the entire length of the glass yarn used for the weft, the ratio of the portion receiving the resistance to the air during the transporting process of the weft or the resistance due to interference with the loom members becomes small. Therefore, the deflection of the weft in the direction perpendicular to the conveying direction or the ballooning motion is stably maintained within a small range. As a result, it is presumed that the damage to the glass yarn due to interference with the loom members, especially the damage received when the glass yarn passes through while being rubbed by the loop guide or the like, can be reduced. Further, when 99.96% or more of the fiber width distribution in the length direction of the glass thread has a fiber bundle width A or less, the glass filaments constituting the glass thread tend to be densely bundled. Therefore, when the glass yarn and the edge of the loom interfere with each other, the damage acting on the glass yarn bundle can be easily dispersed. As a result, it is presumed that the damage received by one filament is suppressed to a small level, making it difficult for the filament to break.

Further, when 99.96% or more of the glass yarn bundle width distribution in the longitudinal direction is equal to or smaller than the yarn bundle width A, the unwinding tension when the weft yarn is unwound from the bobbin can be stably kept small. This keeps the tension variation of the conveyed weft yarn small. Therefore, it is presumed that the deflection of the weft or the ballooning motion can be suppressed, and the damage to the weft can be reduced. When 99.96% or more of the fiber bundle width distribution in the length direction of the glass fiber has the fiber bundle width A or less, it is possible to suppress the occurrence of filament breakage during the transport process from unwinding from the bobbin to ejection. Therefore, the weaving speed (weft driving speed, loom rotation speed) tends to be increased, which is preferable. Compared to the conventional technology (for example, the technology described in Patent Document 3), the present embodiment achieves both suppression of the generation of coarse fluff and securing of stable supply to the market (maintenance of high production speed). It is easy to meet expectations from the perspective of

In addition, since 99.96% or more of the glass yarn bundle width distribution in the length direction has a yarn bundle width A or less, when the glass yarn is used as a warp, it is unwound from the bobbin raw yarn with a creel and the warp is In the process of aligning the yarn, even if the yarn guide or the like rubs against the yarn, it is easy to prevent defects such as fluffing. Therefore, there is a tendency that quality is good and production can be stably performed, which is preferable. In addition, it is preferable to use the above-mentioned glass yarns for the warp yarns, because the warp production speed tends to be increased.

In equations (1) and (3), the reason why x (the tex of the glass yarn) is given a natural logarithm is that the larger (the smaller) the tex of the glass yarn, the greater the change in the tex of the glass. This is because the influence on the yarn conveying track or the like is reduced (increased). Focusing on this point, the present embodiment determines the upper limit of the yarn bundle width for stably obtaining the desired glass cloth quality according to the size or degree of tex, and the length direction It was built on the basis of keeping most things below that upper limit.

In this embodiment, the mass per unit length of the glass thread is 0.5 to 30.0 tex as described above. Therefore, for example, when the mass per unit length of the glass yarn is 0.5 tex, ln(x) is about -0.69, so from equation (1), the yarn bundle width is about -0 .69×68+112=approximately 65 (μm). Further, for example, when the mass per unit length of the glass yarn is 30.0 tex, ln(x) is about 3.4, so from equation (1), the yarn bundle width is about 3.4 x68+112=approximately 343 (μm).
The value "112" as the intercept in the formula (1) has a technical significance of ensuring a predetermined yarn bundle width regardless of changes in tex. The above also applies to the intercept value "80" in equation (3).

Here, with respect to Equation (1), Equation (3) has a smaller intercept value as well as the rate of change. Therefore, the yarn bundle width B determined by the equation (3) is smaller than the yarn bundle width A determined by the equation (1). That is, by using the formula (3) in addition to the formula (1), the yarn bundle width can be adjusted based on a stricter upper limit.

(Thread bundle width of glass thread)
The average yarn bundle width of the glass yarn measured at 50 m in the length direction is equal to or greater than the lower limit value C1-1 given by the following formula (2). In addition, the average yarn bundle width of the glass yarn when measuring 50 m in the length direction is preferably at least the lower limit C1-2 shown by the following formula (4), and the lower limit shown by the following formula (5) A value of C1-3 or more is more preferable, and a lower limit of C1-4 or more represented by the following formula (6) is even more preferable. The lower limits C1-1 to C1-4 of the average yarn bundle width of the glass yarn are each the average yarn bundle width of the glass yarn uniquely determined according to the mass (tex) per unit length of the glass yarn. . Also, the lower limits C1-1 to C1-4 are greater than zero.
Lower limit of average yarn bundle width C1-1 (μm) = 49.0 × ln (x) + 19.5 (2)
Lower limit of average yarn bundle width C1-2 (μm) = 49.5 × ln (x) + 20.0 (4)
Lower limit of average yarn bundle width C1-3 (μm) = 50.0 × ln (x) + 20.5 (5)
Lower limit of average yarn bundle width C1-4 (μm) = 50.5 × ln (x) + 21.5 (6)
x: glass thread tex

When the average yarn bundle width of the glass yarn is at least the above lower limit, when the glass yarn is used as the weft yarn, it receives the ejected air in the weft insertion appropriately, so short picks are less likely to occur, and weaving can be performed with high productivity. easy. In addition, since the average yarn bundle width of the glass yarn is at least the above lower limit, the weft yarn can be easily blown off with a relatively moderate injection pressure, so that the resulting glass cloth tends to be less likely to have fuzz or weaving defects. .

It is preferable that the average yarn bundle width of the glass yarn measured at 50 m in the length direction is equal to or less than the upper limit value C2-1 shown by the following formula (7). Further, the average yarn bundle width of the glass yarn is more preferably less than or equal to the upper limit value C2-2 shown by the following formula (8) when measuring 50 m in the length direction, and is shown by the following formula (9). The upper limit C2-3 or less is more preferable, and the upper limit C2-4 or less represented by formula (10) is even more preferable. Each of the upper limits C2-1 to C-4 of the average fiber bundle width of the glass yarn is the average fiber bundle width of the glass yarn uniquely determined according to the mass (tex) per unit length of the glass yarn. .
Upper limit of average yarn bundle width C2-1 (μm) = 49.0 × ln (x) + 50.0 (7)
Upper limit of average yarn bundle width C2-2 (μm) = 48.0 × ln (x) + 49.0 (8)
Upper limit of average yarn bundle width C2-3 (μm) = 47.0 × ln (x) + 48.0 (9)
Upper limit of average yarn bundle width C2-4 (μm) = 46.0 × ln (x) + 47.0 (10)
x: glass thread tex

When the average yarn bundle width of the glass yarn is equal to or less than the above upper limit, when the glass yarn is used as a warp, it is unwound from the bobbin raw yarn on the creel and rubbed with a yarn guide or the like in the process of aligning the warp. Even in the case of being thin, it is easy to prevent defects such as generation of fluff. Therefore, there is a tendency that quality is good and production can be stably performed, which is preferable. In this regard, it is preferable to use the above-mentioned glass yarns for the warp yarns, because the warp-making speed tends to be increased.

(Breaking strength of glass thread)
The glass thread preferably has a breaking strength of 0.50 to 1.0 N/tex. A preferable range of breaking strength is 0.55 to 0.90 N/tex, a more preferable range is 0.60 to 0.87 N/tex, and a further preferable range is 0.65 to 0.85 N/tex.

If the breaking strength of the glass yarn is 0.50 N/tex or more, when it is used as a weft yarn, it is sheared by coming into contact with a loom member such as a yarn guide during the yarn conveying process until the weft yarn is unwound from the bobbin and ejected. Even when subjected to stress, the filament is hard to break and fluff is hard to occur. Similarly, even if the spouted yarn comes into contact with a loom member such as a reed and is subjected to shearing stress during flying, the filament is less likely to break and fluff is less likely to occur.

If the glass yarn has a breaking strength of 1.0 N/tex or less, when it is used as a weft yarn, the yarn deflection or ballooning movement during the yarn conveying process from the time the weft yarn is unwound from the bobbin until it is ejected is small. tends to be suppressed. Therefore, fluff is less likely to occur due to filament cutting. This is presumed to be due to the flexibility of the glass thread.

(Structure of glass yarn)
A glass thread is obtained by bundling a plurality of glass filaments and, if necessary, by twisting them. In this case, the glass yarn is classified as multifilament, and the glass filament is classified as monofilament.

The elastic modulus of the glass yarn is preferably 50-70 GPa, more preferably 50-63 GPa, still more preferably 53-63 GPa. When the elastic modulus is 50 GPa or more, the rigidity of the glass thread is improved, and fluff is less likely to occur in the manufacturing process. Further, since the elastic modulus is 70 GPa or less, the brittleness resistance of the glass thread is improved, and fluff is less likely to occur in the manufacturing process. Furthermore, since the elastic modulus is within the above range, the glass yarn has moderate flexibility, and when a mechanical load is applied, filament breakage, etc., are unlikely to occur, and fluff and weaving defects are unlikely to occur. Become.

(Glass yarn twist interval length)
The twist interval length of the glass yarn is preferably 1.8 to 4.0 cm, more preferably 1.9 to 3.8 cm, even more preferably 2.0 to 3.6 cm, It is even more preferably 2.0 to 3.4 cm, particularly preferably 2.0 to 3.2 cm, and most preferably 2.0 to 3.2 cm.
If the twist interval length of the glass yarn is equal to or less than the above upper limit, it is preferable because a wide portion of the yarn bundle is less likely to occur, filament breakage and the like are less likely to occur, and fluff and weaving defects are less likely to occur. Furthermore, even if the existence ratio of the wide portion of the yarn bundle is the same, filament breakage or the like is less likely to occur, and fluff and weaving defects are less likely to occur, which is preferable. The reason for these is presumed to be that the continuous length of the wide part of the yarn bundle can be kept short.
When the twist interval length of the glass yarn is at least the above lower limit, the fluff quality of the glass yarn tends to be good, and the quality of the resulting glass cloth is favorable, which is preferable. It is presumed that this is because filament breakage in the glass yarn manufacturing process is suppressed because the torsional shear stress is reduced in the glass yarn manufacturing process.

(Composition of Components of Glass Thread)
Elements constituting the glass thread include silicon (Si), boron (B), aluminum (Al), calcium (Ca), magnesium (Mg), phosphorus (P), sodium (Na), potassium (K), titanium (Ti), zinc (Zn), iron (Fe), fluorine (F), and the like.

The silicon (Si) content of the glass yarn is preferably 40 to 60% by mass, more preferably 45 to 55% by mass, and still more preferably 47.0 to 53.5% by mass in terms of SiO ₂ . , and more preferably 48.0 to 52.0% by mass. Si is a component that forms the skeleton structure of the glass thread. Therefore, when the Si content is 40% by mass or more, the strength of the glass yarn is further improved, and the glass cloth is broken in the subsequent processes such as the glass cloth manufacturing process and the prepreg manufacturing process using the glass cloth. tend to be more suppressed. Moreover, when the Si content is 40% by mass or more, the dielectric constant of the glass cloth tends to be further lowered. On the other hand, when the Si content is 60% by mass or less, the melting viscosity tends to be lower in the glass filament production process, and glass fibers having a more homogeneous glass composition can be obtained. For this reason, the obtained glass filament is less likely to have a portion where it is easy to partially devitrify or a portion where it is difficult for air bubbles to escape partially, so that the glass filament is less likely to have a portion where the strength is locally weak. As a result, the glass cloth composed of the glass yarns obtained using this becomes difficult to break. The Si content can be adjusted according to the amount of raw material used for producing the glass filaments.

The boron (B) content of the glass yarn is preferably 15 to 40% by mass, more preferably 17 to 30% by mass, or 20 to 40% by mass, more preferably 18 to 40% by mass, in terms of B ₂ O ₃ 28% by mass, more preferably 19 to 26% by mass, even more preferably 20 to 25% by mass, most preferably 20.5 to 24.5% by mass.

When the B content is 15% by mass or more, the dielectric constant tends to further decrease. In addition, since the B content is 15% by mass or more, the brittleness resistance of the glass cloth is improved, and the glass cloth is imparted with appropriate flexibility or flexibility, so that the glass yarn can be used as a yarn guide, And when it comes into contact with a loom member such as a reed, fluff tends to be less likely to occur.

On the other hand, in order to maintain the strength of the glass yarn, the B content is preferably 40% by mass or less. When the B content is 40% by mass or less, the moisture absorption resistance is improved, and the stability of the glass yarn surface properties, which will be described later, is likely to be properly maintained.

In particular, it is preferable that the Si content and the B content in the glass yarn are within the above range, because the above effects of Si and B are likely to be synergistically exhibited.

The B content can be adjusted by the amount of raw material used (amount charged) for producing the glass filaments. If the production conditions, the amount used, or the content may vary during production of the glass filaments, it is possible to anticipate such fluctuations and adjust the amount of raw material to be charged.

The aluminum (Al) content of the glass yarn is preferably 11 to 18% by mass, more preferably 11 to 17.5% by mass, and still more preferably 12 to 17.0% by mass in terms of Al ₂ O ₃ is. When the Al content is within the above range, electrical properties and strength tend to be further improved. The Al content can be adjusted by the amount of raw material used (amount charged) for producing the glass filaments.

The calcium (Ca) content of the glass thread is preferably 5.0 to 10% by mass, more preferably 5.0 to 9.0% by mass, and still more preferably 5.0 to 8.0% by mass in terms of CaO. 5% by mass. When the Ca content is 5.0% by mass or more, the viscosity during melting tends to be lower in the glass filament production process, and glass fibers with a more homogeneous glass composition tend to be obtained. Moreover, when the Ca content is 10% by mass or less, the dielectric constant tends to be further improved. The Ca content can be adjusted by the amount of raw materials used (amount charged) for producing the glass filaments.

The phosphorus (P) content of the glass yarn is preferably 8.0% by mass or less, more preferably 7.0% by mass or less, and still more preferably 6.0% by mass or less in terms of P ₂ O ₄ be. The P content may be greater than 0% by weight. When the P content exceeds 0% by mass, the glass cloth tends to have better dielectric properties. Further, when the P content is 8.0% by mass or less, the heat resistance of the glass cloth tends to be improved. The P content can be adjusted by the amount of raw material used (amount charged) for producing the glass filaments.

Each of the above contents can be measured by ICP emission spectrometry. Specifically, the Si content and the B content are obtained by melting a weighed glass cloth with sodium carbonate and then dissolving it with dilute nitric acid to a predetermined volume, and measuring the resulting sample by ICP emission spectrometry. Obtainable. Further, the Fe content can be obtained by dissolving the weighed glass cloth by an alkaline dissolution method to obtain a predetermined volume, and measuring the obtained sample by ICP emission spectrometry. Furthermore, the Al content, Ca content, P content and Mg content were obtained by thermally decomposing the weighed glass cloth with perchloric acid, sulfuric acid, nitric acid and hydrogen fluoride, and then dissolving it in dilute nitric acid to a predetermined volume. measured by ICP emission spectroscopy. PS3520VDD II manufactured by Hitachi High-Tech Science Co., Ltd. can be used as the ICP emission spectrometer.

(Dielectric constant of glass thread)
The dielectric constant of the glass yarn is preferably 5.0 or less, more preferably 4.9 or less, still more preferably 4.8 or less, and particularly preferably 4.6 or less at a frequency of 10 GHz. . Permittivity can be measured, for example, by a cavity resonance method. In this embodiment, the dielectric constant refers to a dielectric constant at a frequency of 10 GHz unless otherwise specified.

(Dielectric loss tangent of glass thread)
The dielectric loss tangent of the glass yarn is preferably 0.0050 or less, more preferably 0.0040 or less, still more preferably 0.0035 or less, and particularly preferably 0.0030 or less at a frequency of 10 GHz. . A dielectric loss tangent can be measured, for example, by a cavity resonance method. In this embodiment, the dielectric loss tangent refers to a frequency of 10 GHz unless otherwise specified.

[Method for manufacturing glass cloth]
This embodiment is a method for producing a glass cloth having a thickness of 8 to 100 μm, which is obtained by weaving glass yarns containing a plurality of glass filaments as warp and weft yarns, and uses the glass yarns as the weft yarns. That is, the method for manufacturing a glass cloth according to the present embodiment includes a step of weaving the glass yarn as a weft. The glass yarn may be woven as weft and warp. Specifically, in this embodiment,
99.96% or more of the length direction when measuring 50 m in the length direction is the yarn bundle width A or less, and the yarn bundle average value when measuring 50 m in the length direction is more than the yarn bundle width C Prepare a glass yarn. a yarn preparation step (also referred to as a “yarn bundle width adjustment step” in the present embodiment);
a weaving step of weaving the prepared glass threads to obtain a glass cloth;
A fiber opening step of opening the glass yarn of the glass cloth,
may have In addition, according to the present embodiment, if necessary,
A desizing step of reducing the sizing agent adhering to the glass yarn of the glass cloth, and/or a surface treatment step of surface-treating the glass cloth or the glass yarn with a silane coupling agent,
may have Each step of this embodiment will be described below.

[Thread preparation process (yarn bundle width adjustment process)]
In the yarn preparation process (yarn bundle width adjustment process), 99.96% or more in the length direction when measuring 50 m in the length direction is the yarn bundle width A or less, and the yarn bundle average value when measuring 50 m in the length direction A glass yarn having a width equal to or larger than the yarn bundle width C is prepared. Specifically, in the yarn bundle width adjustment step, if the yarn bundle width distribution in the length direction is within the above range, the glass yarn is used in the subsequent weaving process, and if it is outside the range, the yarn is discarded. Then, the glass thread itself is replaced with another one, or the glass thread is rewound and adjusted so that it falls within the above range. Even when the fiber bundle width distribution in the length direction is within the above range, the glass fiber itself may be replaced, or the fiber bundle width may be adjusted by rewinding the glass fiber.

Alternatively, in the yarn bundle width adjustment process, feedback may be provided to the glass yarn manufacturing process to adjust the yarn manufacturing conditions. It is thought that the portion where the yarn bundle width of the glass yarn is locally wide is likely to occur in the portion where the tension acts locally weakly when the glass yarn is wound, or in the portion where the twist density is low. Therefore, it may be possible to adjust the yarn bundle width distribution of the glass yarn supplied to the weaving process by rewinding the glass yarn. When feedback is provided to the glass yarn manufacturing process and the yarn manufacturing conditions are adjusted, the tension when winding the glass yarn, the tension when twisting, and their fluctuations from the same viewpoint By adjusting the range, it is possible to adjust the bundle width distribution. If adjustment is difficult due to rewinding of the glass thread or the like, or from the viewpoint of production efficiency, the glass thread itself can be replaced.

The glass yarn prepared at this time (for adjusting the yarn bundle width) has a mass per unit length of 0.5 to 30.0 tex and a density of 1.8 g/cm ³ or more and 2.5 g/cm ^{3 .} is less than Adjustments to the mass per unit length and/or density may be made in the yarn preparation process.

[Weaving process]
The weaving step is a step of weaving the glass threads prepared above to obtain a glass cloth. In the weaving method, the weft and warp are woven so as to form a predetermined woven structure. Examples of the weave structure of the glass cloth include plain weave, Nanako weave, satin weave, and twill weave. Among these, the plain weave structure is more preferable.

In one embodiment, the warp yarns drawn in parallel are opened vertically by an air jet loom method, and the yarn (weft) supplied from the weft storage device is sent out by the jet flow of the nozzle and passed through the opening. Thus, weaving can be performed.

The weaving process may include a glass yarn ejection process that unwinds the glass yarn, which will become the weft yarn, from a bobbin and ejects the weft yarn through a storage device. In this process of ejecting the glass yarn, the glass yarn is conveyed with interference with a loom member such as a yarn guide while accompanying movement in a direction different from the advancing direction, such as ballooning movement. Alternatively, since the weft is repeatedly spouted and stopped in units of the length of one weft, the weft is conveyed with interference with a loom member such as a yarn guide while the tension fluctuates. For the above reason, it is difficult to suppress the above-mentioned interference in the weft yarn, which has a large portion of the yarn bundle having a large width, so that the resulting glass cloth tends to have fluff or weaving defects.

On the other hand, in this embodiment, 99.96% or more in the length direction when measuring 50 m in the length direction is the yarn bundle width A or less, and the length By using a glass yarn having a bundle average value of not less than the bundle width C when measured in the longitudinal direction of 50 m, especially as the weft yarn, the generation of fluff or weaving defects during weaving of the glass yarn (weft yarn) is suppressed. Thereby, the in-plane uniformity of the quality of the glass cloth and the uniformity between lots can be improved. The weaving method is not limited to the air jet loom method, and may be a water jet loom method or a shuttle method.

The driving speed of the wefts constituting the glass cloth is preferably more than 350 threads per minute. In general, the quality of the glass cloth tends to decrease as the production speed (the number of rotations of the loom) increases. However, according to this embodiment, the glass cloth of excellent quality can be obtained even when the number of rotations of the loom exceeds 350 rpm. Even if the weft driving speed is 400 wefts/minute or more, 500 wefts/minute or more, or 560 wefts/minute or more, according to this embodiment, a glass cloth having excellent quality can be obtained. The weft driving speed may be 1000 threads/minute or less, 800 threads/minute or less, or 700 threads/minute or less.

According to the present embodiment, even when the production speed of the cloth is increased in order to ensure a stable supply to the market, the glass cloth has less variation in quality, has good quality, and has a low dielectric. can be made.
In this regard, there is a strong desire for expansion of the service area of high-speed communication systems, typified by fifth-generation mobile communication systems, that is, for sufficient communication infrastructure such as base stations. Under such circumstances, it is strongly expected to improve the production speed and provide a stable supply of low-dielectric glass cloth, which is a member required for communication infrastructure. This embodiment meets such expectations. In other words, the glass cloth, and thus the glass yarn, according to the present embodiment are suitable for the glass cloth and, by extension, the glass yarn, which are used in high-speed communication infrastructure.
"High-speed communication infrastructure" refers to the infrastructure (base) for realizing high-speed communication, including base stations for high-speed communication and various industrial bases.

The density of warps and wefts forming the glass cloth is preferably 30 to 90/inch, more preferably 40 to 80/inch, still more preferably 50 to 75/inch. The warp driving density can be controlled by adjusting the spacing between the warp yarns drawn in parallel, and the weft driving density is controlled by the number of weft jets per unit time from the nozzle and the warp flow speed. be able to. Since 1 inch is 25.4 mm, the implantation density per inch can be converted to the implantation density in millimeter order.

Further, the thickness of the glass cloth finally obtained through the opening process and the like is 8 to 100 μm. It is preferably 9 to 98 μm, more preferably 10 to 96 μm. When the thickness of the glass cloth is within the above range, there is a tendency to obtain a thin glass cloth with relatively high strength.
The cloth mass (basis weight) of the glass cloth is preferably 5 to 100 g/m ² , more preferably 6 to 98 g/m ² , still more preferably 7 to 97 g/m ² , particularly preferably 7 to 97 g/m 2 . 96 g/m ² .

[Opening process]
In the opening step, the glass yarns of the glass cloth are opened. Examples of the fiber-opening method include a method of fiber-opening using spray water (high-pressure water fiber opening), vibro washer, ultrasonic water, mangle, or the like.

[Degluing process]
In the desizing step, the sizing agent (also referred to as "sizing agent") adhering to the glass threads of the glass cloth is reduced. Examples of the desizing method include a method of reducing the sizing agent by heating.

[Surface treatment process]
In the surface treatment step, a silane coupling agent is used to surface-treat the glass cloth or glass yarn. Examples of the surface treatment method include a method in which a surface treatment agent containing a silane coupling agent is brought into contact with glass cloth or glass yarn and dried. The contact of the surface treatment agent with the glass cloth or glass yarn is achieved by penetrating the glass cloth or glass yarn into the surface treatment agent; surface treatment of the glass cloth or glass yarn using a roll coater, die coater, gravure coater, or the like. method of applying an agent; and the like. Examples of drying methods for the surface treatment agent include hot air drying and drying methods using electromagnetic waves.

(surface treatment)
The glass cloth or glass thread may be surface-treated with a surface treatment agent. Examples of surface treatment agents include silane coupling agents, and if necessary, water, organic solvents, acids, dyes, pigments, surfactants, and the like may be used in combination.

Examples of silane coupling agents include the following formula (11):
X(R)3-nSiYn (11)
(In formula (11), X is an organic functional group having at least one or more of an amino group and an unsaturated double bond group, Y is each independently an alkoxy group, and n is 1 or more. is an integer of 3 or less, and each R is independently a group selected from the group consisting of a methyl group, an ethyl group and a phenyl group.). In formula (11), X is preferably an organic functional group having at least three or more of an amino group and an unsaturated double bond group, and X is at least an amino group and an unsaturated double bond group. Organic functional groups having four or more are more preferred.

As the alkoxy group in the formula (11), any form can be used, but an alkoxy group having 5 or less carbon atoms is preferable from the viewpoint of stabilizing the glass cloth.

Specific examples of the silane coupling agent include N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-vinylbenzylaminoethyl)- γ-Aminopropylmethyldimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-di(vinyl benzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltrimethoxysilane and its Hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl) Known simple substances such as aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, or mixtures thereof can be mentioned.

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

〔Glass cloth〕
The glass cloth according to the present embodiment is a glass cloth containing the above glass yarns as wefts. In one aspect, the glass cloth may contain the above glass yarns as weft yarns and warp yarns. The method for manufacturing the glass cloth is as described above, and includes at least the yarn preparation step (yarn bundle width adjustment step).

(Dielectric constant of glass cloth)
The dielectric constant of the obtained glass cloth is preferably 5.0 or less, more preferably 4.9 or less, still more preferably 4.8 or less, and particularly preferably 4.6 or less at a frequency of 10 GHz. is. Permittivity can be measured, for example, by a cavity resonance method. In this embodiment, the dielectric constant refers to the dielectric constant at a frequency of 10 GHz unless otherwise specified.

(Dielectric loss tangent of glass cloth)
The dielectric loss tangent of the resulting glass cloth is preferably 0.0050 or less, more preferably 0.0040 or less, still more preferably 0.0030 or less, and particularly preferably 0.0025 or less at a frequency of 10 GHz. is. Permittivity can be measured, for example, by a cavity resonance method. In this embodiment, the dielectric constant refers to the dielectric constant at a frequency of 10 GHz unless otherwise specified.

[Prepreg]
The prepreg according to this embodiment has the glass cloth obtained as described above and the matrix resin composition impregnated in the glass cloth. A prepreg having the above glass cloth has little variation in quality and a high yield of the final product. In addition, since prepregs have excellent dielectric properties and excellent moisture absorption resistance, it is possible to provide a printed wiring board that is not easily affected by the environment in which it is used (especially in a high-humidity environment, the fluctuation of the dielectric constant is small). can.

The prepreg according to this embodiment can be manufactured according to a conventional method. For example, after impregnating a glass cloth with a varnish obtained by diluting a matrix resin such as an epoxy resin with an organic solvent, the organic solvent is volatilized in a drying oven to bring the thermosetting resin into a B-stage state (semi-cured state). It can be produced by curing to

As the matrix resin composition, thermosetting resins such as bismaleimide resins, cyanate ester resins, unsaturated polyester resins, polyimide resins, BT resins, and functionalized polyphenylene ether resins, in addition to the epoxy resins described above; , polyetherimide resin, liquid crystal polymer (LCP) of wholly aromatic polyester, polybutadiene, thermoplastic resin such as fluororesin; and mixed resin thereof. From the viewpoint of improving dielectric properties, heat resistance, solvent resistance, and press moldability, a resin obtained by modifying a thermoplastic resin with a thermosetting resin may be used as the matrix resin composition.

In addition, the matrix resin composition contains inorganic fillers such as silica and aluminum hydroxide in the resin; flame retardants such as bromine-based, phosphorus-based, and metal hydroxides; other silane coupling agents; heat stabilizers; pigments; colorants; lubricants and the like.

[Printed wiring board]
A printed wiring board according to the present embodiment includes the prepreg. The printed wiring board according to the present embodiment has little variation in quality and a high yield of the final product. In addition, since it has excellent dielectric properties and excellent resistance to moisture absorption, it is less susceptible to the use environment (particularly, the dielectric constant fluctuates less in a high-humidity environment).

Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is by no means limited by the following examples.

[Physical properties of glass thread and glass cloth]
Physical properties of glass yarn and glass cloth, specifically, thickness of glass cloth, diameter and average diameter of filaments constituting glass yarn, number of filaments, breaking strength (tensile strength) of glass yarn, driving of warp and weft Density (woven density) was measured according to JIS R3420.

[Electrical properties of glass cloth]
Measure the dielectric constant and dielectric loss tangent of each glass cloth in accordance with JIS R1641/IEC 62562, which defines the method of measuring dielectric properties in the microwave band of fine ceramic materials for dielectric substrates mainly used in microwave circuits. bottom. Specifically, a glass cloth sample of the size required for measurement in each resonator was stored in a constant temperature and humidity oven at 23°C and 50% RH for 8 hours or more to condition the humidity, and then the split cylinder resonator was placed. (manufactured by EM Lab) and an impedance analyzer (manufactured by Agilent Technologies). The measurement was performed 5 times for each sample, and the average value was obtained. The thickness of each sample was measured using a converted thickness obtained by dividing the basis weight of each glass cloth by the density. The glass cloths obtained in Examples 1, 10, 11 and Reference Example 1 were evaluated for electrical properties.
Converted thickness (μm) = basis weight (g/m ² )/density (g/cm ³ )

[Elastic modulus]
The elastic modulus of the glass yarn was measured by the pulse-echo overlap method using a glass bulk obtained by melting and cooling the glass yarn as a test piece.

[Composition of glass yarn]
The composition constituting the glass thread was measured by ICP emission spectrometry. Specifically, Si content and B content were measured as follows. After decomposing the weighed glass cloth under pressure with sodium hydroxide, it was dissolved with dilute nitric acid, and undissolved matter was separated by filtration. The insoluble matter was dissolved with sodium carbonate, dissolved with dilute nitric acid, and combined with the filtrate to make a predetermined volume to obtain a sample. The resulting sample was measured by ICP emission spectrometry to obtain the Si content and B content in terms of SiO ₂ and B ₂ O ₃ , respectively.

Al content, Ca content, Mg content, and P content were measured as follows. The weighed glass cloth was thermally decomposed with perchloric acid, sulfuric acid, nitric acid and hydrogen fluoride, then heated and dissolved with dilute aqua regia, and the undissolved portion was separated by filtration. The filtrate was brought to a predetermined volume. The insoluble matter was thermally decomposed with sulfuric acid, nitric acid, hydrochloric acid and hydrogen fluoride, and then heated and dissolved with dilute aqua regia to obtain a predetermined volume. These solutions (samples) having a predetermined volume were measured by ICP emission spectrometry, the contents in the samples were determined, and converted into oxide values corresponding to the target metal elements. As the ICP emission spectrometer, PS3520VDD II manufactured by Hitachi High-Tech Science Co., Ltd. was used (same as above).

[Measurement of yarn bundle width distribution]
While conveying the glass yarn at a speed of 1 m / min, measure the yarn bundle width of the glass yarn over 50 m using an LED projection type transmission type dimension measuring device (HIGH ACCURACY CMOS MICROMETER LS-9006MR / manufactured by Keyence) bottom. From the obtained yarn bundle width data for a length of 50 m, the ratio of yarn bundle widths below a specific yarn bundle width and the average value of yarn bundle widths were calculated.

Yarn bundle width measurement with an LED projection type transmissive dimension measuring instrument is performed under the condition that 1934 measurement values per 1m can be obtained, and if an error occurs due to the LED not being focused (-9999 value is displayed ), the measured value was deleted, and the ratio of the above-mentioned specific yarn bundle width value or less and the average value of the yarn bundle width were calculated. In addition, the calculation can be performed by appropriately omitting measurement values that cause errors.

The tension acting on the glass yarn when the glass yarn was transported was 0.12 to 0.18 N when measured with a tension meter (Conrol instruments ETPB-100-C0585 manufactured by SCHMIDT).

[Evaluation 1: Weaving (short pick)]
In the weaving process using the air jet loom in the examples and comparative examples, the number of times the weaving was stopped was counted during the process of weaving a glass cloth of 2100 m, and the weaving performance was evaluated according to the following evaluation criteria.
6: Stopped 0 times.
5: Stop 1-2 times.
4: Stop 3-4 times.
3: Stop 5-7 times.
2: 8-12 stops.
1: 13 or more stops

[Evaluation 2: Cloth quality (coarse fluff)]
2000 m of glass cloth was unwound from the glass cloth rolls obtained in Examples and Comparative Examples, and the presence or absence of fuzz and weaving defects was checked, and the quality was evaluated according to the following evaluation criteria. The evaluation results "1" and "2" were set as unacceptable.
6: Coarse fluff of 1 mm or more was not confirmed.
5: 1 to 7 coarse fluffs of 1 mm or more were confirmed, but no coarse fluffs of 2 mm or more were observed.
4: 8 to 29 coarse fluffs of 1 mm or more were observed, but no coarse fluffs of 2 mm or more were observed.
3: 30 or more coarse fluffs of 1 mm or more and less than 2 mm were observed, but no coarse fluff of 2 mm or more was observed.
2: 1 to 29 coarse fluffs of 2 mm or more were confirmed.
30 or more coarse fluffs of 1:2 mm or more were confirmed.

[Evaluation 3: Electrical properties of evaluation substrate (dielectric loss tangent)]
Using the glass cloths obtained in Examples and Comparative Examples, test pieces for electrical property measurement were produced under the following conditions, and the dielectric loss tangent was measured.

The glass cloths obtained in Examples and Comparative Examples are continuously pulled out and transported, the glass cloths are permeated into the varnish, passed through a slit to adjust the amount of varnish applied, and then passed through a drying oven at 120 ° C. After drying, a prepreg was obtained. The varnish contains 65 parts by mass of methacrylated polyphenylene ether, 35 parts by mass of triallyl isocyanurate, 10 parts by mass of hydrogenated styrene thermoplastic elastomer, 25 parts by mass of brominated flame retardant, 65 parts by mass of spherical silica, and 1 part by mass of organic peroxide. Parts by weight and 210 parts by weight of toluene were used, and the resin content was adjusted to 73% by weight.

A predetermined number of the obtained prepregs are stacked, and copper foil (manufactured by Furukawa Electric Co., Ltd., thickness 18 μm, GTS-MP foil) is superimposed on both sides of the prepregs, and vacuum pressing is performed. , to obtain a copper-clad laminate. Next, a laminate was obtained by removing the copper foil from the copper-clad laminate by etching.

A test piece having a length of about 50 mm and a width of about 1.5 mm was cut out from the obtained laminated plate so that the warp of the glass cloth was on the long side, placed in an oven at 105 ° C. ± 2 ° C., and dried for 2 hours. After that, the dielectric loss tangent at 10 GHz was measured under the following conditions.
Standard conditions: 23±2° C., 50±5% relative humidity, in a constant temperature room, the test piece is left to stand for 96 hours and then measured.

For the measurement equipment, use a network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (CavityResonator CP series) manufactured by Kanto Denshi Applied Development Co., Ltd., and measure under an environment of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. did Five test pieces were cut out for each measurement, and the average value was taken as the value of the dielectric loss tangent.

<Weaving test 1: glass cloth with a thickness of 29 μm>
[Comparative Examples 1 to 4]
Glass yarn having the composition shown in the table below (average glass filament diameter: 5.1 μm, number of filaments: 100) was used for the warp and weft, and the loom rotation speed of the air jet loom was set to the conditions shown in the table below, and the warp was woven. A glass cloth greige fabric having a density of 65 threads/25 mm and a weft density of 67 threads/25 mm was obtained. Next, desizing treatment was performed by heating, a fiber opening process was performed by spraying high-pressure water, and surface treatment was performed using a silane coupling agent to prepare a glass cloth having a thickness of about 29 μm.

2000 m of glass cloth was unwound from the glass cloth roll obtained in the comparative example. The quality of the cloth was evaluated based on the condition that the loom rotation speed was 350 rpm (the weft driving speed was 350 per minute).
A: It was confirmed that the number of coarse fluffs of 2 mm or more decreased.
B: It was confirmed that the number of coarse fluffs of 2 mm or more was about the same.
C: It was confirmed that the number of coarse fluffs of 2 mm or more increased.

[Examples 1-11, Comparative Examples 2, 4-8, Reference Examples 1-2]
A glass cloth having a thickness of 29 μm was produced in the same manner as in Comparative Example 1, except that the rotation speed of the loom in the air jet loom was 600 rpm.

The breaking strength of the glass yarn subjected to the weaving test, the evaluation result of the weavability at the time of weaving, the quality of the glass cloth, and the electrical properties were as shown in the table below.

The production methods of Examples 1 to 11 yielded glass cloths with excellent weavability and cloth quality. Among them, Examples 1, 2, 3, 5, 6, 7, 8, 10, and 11, in which the proportion of the wide portion of the weft yarn was small, were particularly excellent in glass cloth quality.
In Examples 6, 7, and 8, in which the maximum value of the twist interval length falls within a predetermined range, the existence ratio of the wide portion of the yarn bundle is the same, and the maximum value of the twist interval length is relatively high. As compared with Example 3, which has a large size, a glass cloth having better cloth quality was obtained.

In Example 11, although the existence ratio of the portion having a wide yarn bundle width was small, coarse fluff tended to occur slightly more than in Examples 1, 2, 5, 6, 7, 8 and 10. The inventors presume that the reason for this is that the cloth obtained in Example 11 has a relatively large elastic modulus.

In Example 5, the warp uses glass yarn having many wide portions, but the weft uses glass yarn having few wide portions, so that a glass cloth with good cloth quality is obtained. was taken. On the other hand, in Example 4, in which the proportion of portions with wide yarn widths (weft width) was slightly higher than in Example 5, coarse fluff tended to occur in a slightly larger quantity.

When the rotation speed of the loom was increased to 600 rpm in Comparative Examples 2 and 4, a large amount of coarse fluff was generated, and only the glass cloth of inferior quality was obtained. In Comparative Examples 1 and 2, the width of the bundle of the glass yarns was small overall, so that sufficient flight performance was not obtained, and many short picks occurred, resulting in poor weaving performance. From Comparative Examples 1 to 4, cloth quality tended to decrease as the production speed increased.

In the production methods of Examples 1 to 11, high-quality glass cloths were obtained even though the loom rotation speed was 600 rpm.
Reference Examples 1 and 2 show the production of glass cloth using conventional E-glass yarn. A glass cloth excellent in weavability and quality was obtained, but the electrical properties were inferior to those of the glass cloths of Examples 1 to 11.

[Examples 12 to 14, 35, 36, Comparative Examples 9, 16]
<Weaving test 2: 14 μm thick glass cloth>
Glass yarn having the composition shown in the table below (average glass filament diameter: 4.0 μm, number of filaments: 50) was used for the warp and weft, and the loom rotation speed of the air jet loom was 600 rpm (weft driving speed: 600 / min). Under the conditions of , a glass cloth green fabric with a warp weaving density of 95/25 mm and a weft weaving density of 95/25 mm was obtained. Next, desizing treatment was performed by heating, a fiber opening process was performed by spraying high-pressure water, and then surface treatment was performed using a silane coupling agent to prepare a glass cloth having a thickness of about 14 μm.
The breaking strength of the glass yarn subjected to the weaving test, the evaluation result of the weavability at the time of weaving, and the quality of the glass cloth were as shown in the table below.

The production methods of Examples 12 to 14, 35, and 36 yielded glass cloths excellent in weavability and cloth quality. On the other hand, the glass cloths obtained by the manufacturing methods of Comparative Examples 9 and 16 had a large amount of coarse fluff and were inferior in quality.

[Examples 15 to 18, Comparative Example 10]
<Weaving test 3: 21 μm thick glass cloth>
Glass yarn having the composition shown in the table below (average diameter of glass filament: 4.0 μm, number of filaments: 100) was used for the warp and weft, and the loom rotation speed of the air jet loom was 600 rpm (weft driving speed: 600 / min). Under the conditions of , a glass cloth green fabric with a warp weaving density of 74/25 mm and a weft weaving density of 74/25 mm was obtained. Next, desizing treatment was performed by heating, a fiber opening process was performed by spraying high-pressure water, and then surface treatment was performed using a silane coupling agent to prepare a glass cloth having a thickness of about 21 μm.

The breaking strength of the glass yarn subjected to the weaving test, the evaluation result of the weavability at the time of weaving, and the quality of the glass cloth were as shown in the table below.

The production methods of Examples 15 to 18 yielded glass cloths excellent in weavability and cloth quality. On the other hand, the glass cloth obtained by the manufacturing method of Comparative Example 10 had a large amount of coarse fluff and was inferior in quality.

[Examples 19 to 24, Comparative Examples 11 and 12]
<Weaving test 4: 46 μm thick glass cloth>
Glass yarn having the composition shown in the table below (average glass filament diameter: 5.1 μm, number of filaments: 200) was used for the warp and weft, and the rotation speed of the loom in the air jet loom was 600 rpm (weft driving speed: 600 / min). A glass cloth greige with a warp weaving density of 52.5/25 mm and a weft weaving density of 52.5/25 mm was obtained. Next, desizing treatment was performed by heating, a fiber opening process was performed by spraying high-pressure water, and then surface treatment was performed using a silane coupling agent to prepare a glass cloth having a thickness of about 46 μm.

The breaking strength of the glass yarn subjected to the weaving test, the evaluation result of the weavability at the time of weaving, and the quality of the glass cloth were as shown in the table below.

The production methods of Examples 19 to 24 yielded glass cloths with excellent weavability and cloth quality. On the other hand, the glass cloths obtained by the manufacturing methods of Comparative Examples 11 and 12 had a large amount of coarse fluff and were inferior in quality.

[Examples 25 to 28, Comparative Example 13]
<Weaving test 5: 73 μm thick glass cloth>
Glass yarns having the composition shown in the table below (average glass filament diameter: 6.1 µm, number of filaments: 200) were used for the warp and weft, and the rotation speed of the loom in the air jet loom was 600 rpm (weft driving speed: 600 yarns/minute). Under the conditions of , a glass cloth green fabric with a warp weaving density of 59/25 mm and a weft weaving density of 61/25 mm was obtained. Next, desizing treatment was performed by heating, a fiber opening process was performed by spraying high-pressure water, and surface treatment was performed using a silane coupling agent to prepare a glass cloth having a thickness of about 73 μm.

The breaking strength of the glass yarn subjected to the weaving test, the evaluation result of the weavability at the time of weaving, and the quality of the glass cloth were as shown in the table below.

The production methods of Examples 25 to 28 yielded glass cloths excellent in weavability and cloth quality. On the other hand, the glass cloth obtained by the manufacturing method of Comparative Example 13 had a large amount of coarse fluff and was inferior in quality.

[Examples 29 to 34, Comparative Examples 14 and 15]
<Weaving test 6: glass cloth with a thickness of 92 μm>
Glass yarns having the composition shown in the table below (average glass filament diameter: 6.1 µm, number of filaments: 200) were used for the warp and weft, and the rotation speed of the loom in the air jet loom was 600 rpm (weft driving speed: 600 yarns/minute). Under the conditions of , a glass cloth green fabric with a warp weaving density of 60/25 mm and a weft weaving density of 57/25 mm was obtained. Next, desizing treatment was performed by heating, a fiber opening process was performed by spraying high-pressure water, and then surface treatment was performed using a silane coupling agent to prepare a glass cloth having a thickness of about 92 μm.

The breaking strength of the glass yarn subjected to the weaving test, the evaluation result of the weavability at the time of weaving, and the quality of the glass cloth were as shown in the table below.

The production methods of Examples 29 to 34 yielded glass cloths excellent in weavability and cloth quality. On the other hand, the glass cloths obtained by the manufacturing methods of Comparative Examples 14 and 15 had a large amount of coarse fluff and were inferior in quality.

Claims (22)

A method for producing a glass cloth having a thickness of 8 to 100 μm, comprising weaving glass yarns containing a plurality of glass filaments as warp yarns and weft yarns,
As the weft,
The mass per unit length is 0.5 to 30.0 tex,
a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ ;
When measuring 50 m in the length direction, 99.96% or more in the length direction is the following formula (1):
A (μm)=68×ln(x)+112 (1)
x: glass thread tex
is equal to or less than the yarn bundle width A indicated by
The average yarn bundle width when measuring 50 m in the length direction is the following formula (2):
C (μm)=49.0×ln(x)+19.5 (2)
x: glass thread tex
A method for manufacturing a glass cloth using a glass thread that is equal to or higher than the lower limit value C indicated by. As the weft,
When measuring 50 m in the length direction, 98.00% or more in the length direction is the following formula (3):
B (μm)=75×ln(x)+80 (3)
x: glass thread tex
2. The method for producing a glass cloth according to claim 1, wherein the glass yarn is less than or equal to the yarn bundle width B represented by. The method for producing a glass cloth according to claim 1 or 2, wherein the glass yarn has a twist interval length of 1.8 to 4.0 cm. The glass yarn has a silicon (Si) content of 40 to 60% by mass in terms of silicon dioxide (SiO ₂ ) and a boron (B) content of 15 to 40% by mass in terms of boron oxide (B ₂ O ₃ ). is used as the weft yarn. 5. The method for producing a glass cloth according to claim 4, wherein said glass yarn having a B content of 20 to 40% by mass in terms of B ₂ O ₃ is used as said weft yarn. 3. The method for producing a glass cloth according to claim 1, wherein the glass yarn having an elastic modulus of 50 to 70 GPa is used as the weft yarn. 3. The method for producing a glass cloth according to claim 1, wherein the glass yarn having an elastic modulus of 50 to 63 GPa is used as the weft yarn. The method for producing a glass cloth according to claim 1 or 2, wherein the weft yarn is woven at a driving speed of more than 350 and 1000 or less per minute. A glass yarn used for the weft of glass cloth,
The glass yarn is
The mass per unit length is 0.5 to 30.0 tex,
a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ ;
When measuring 50 m in the length direction, 99.96% or more in the length direction is the following formula (1):
A (μm)=68×ln(x)+112 (1)
x: glass thread tex
is equal to or less than the yarn bundle width A indicated by
The average yarn bundle width when measuring 50 m in the length direction is the following formula (2):
C (μm)=49.0×ln(x)+19.5 (2)
x: glass thread tex
A glass thread that is equal to or higher than the lower limit value C indicated by. The glass yarn is
When measuring 50 m in the length direction, 98.00% or more in the length direction is the following formula (3):
B (μm)=75×ln(x)+80 (3)
x: glass thread tex
The glass yarn according to claim 9, which is equal to or less than the yarn bundle width B indicated by. The glass yarn according to claim 9 or 10, wherein the glass yarn has a twist interval length of 1.8 to 4.0 cm. The silicon (Si) content is 40 to 60% by mass in terms of silicon dioxide (SiO ₂ ), and the boron (B) content is 15 to 40% by mass in terms of boron oxide (B ₂ O ₃ ). The glass yarn according to 9 or 10. 13. The glass yarn according to claim 12, wherein the B content is 20-40% by mass in terms of B ₂ O ₃ . The glass yarn according to claim 9 or 10, which has an elastic modulus of 50 to 70 GPa. The glass yarn according to claim 9 or 10, which has an elastic modulus of 50 to 63 GPa or less. 11. The glass yarn according to claim 9 or 10, having a dielectric constant of 5.0 or less at a frequency of 10 GHz. 11. The glass yarn according to claim 9 or 10, having a dielectric loss tangent of 0.0050 or less at a frequency of 10 GHz. 11. The glass yarn according to claim 9 or 10, which is used for weaving glass cloth for use in high-speed communication infrastructure. A glass cloth comprising the glass yarn according to claim 9 or 10. 20. The glass cloth of claim 19, having a dielectric constant of 5.0 or less at a frequency of 10 GHz. 20. The glass cloth according to claim 19, which is used for high-speed communication infrastructure. A glass yarn sorting method suitable for producing a glass cloth by weaving glass yarns as warp and weft,
As the weft,
The mass per unit length is 0.5 to 30.0 tex,
a density of 1.8 g/cm ³ or more and less than 2.5 g/cm ³ ;
When measuring 50 m in the length direction, 99.96% or more in the length direction is the following formula (1):
A (μm)=68×ln(x)+112 (1)
x: glass thread tex
is equal to or less than the yarn bundle width A indicated by
The average yarn bundle width when measuring 50 m in the length direction is the following formula (2):
C (μm)=49.0×ln(x)+19.5 (2)
x: glass thread tex
A method for sorting glass yarns, comprising a step of sorting glass yarns that are equal to or higher than the lower limit value C indicated by.