CN114207203B

CN114207203B - Glass cloth, prepreg and printed circuit board

Info

Publication number: CN114207203B
Application number: CN202080052374.1A
Authority: CN
Inventors: 本间裕幸
Original assignee: Asahi Kasei Corp
Current assignee: Asahi Kasei Corp
Priority date: 2019-12-16
Filing date: 2020-12-03
Publication date: 2023-07-21
Anticipated expiration: 2040-12-03
Also published as: TW202142750A; JP7371122B2; TWI827895B; JPWO2021124913A1; KR20220037515A; WO2021124913A1; KR102633930B1; CN114207203A

Abstract

A glass cloth (1) is provided, which is formed by using glass yarns formed by a plurality of glass filaments as warp yarns and weft yarns, wherein the width (t) of the glass cloth in The Direction (TD) forming 90 DEG with the warp yarns is more than 1000mm, the glass cloth (1) has a relative dielectric constant (Dk) below 5.0 and a thickness below 35 mu m, and the relaxation amount (x maximum value) in the vertical direction (z) when the tension in the direction (MD) parallel to the warp yarns is set to 50N is less than 10 mm/m.

Description

Glass cloth, prepreg and printed circuit board

Technical Field

The present invention relates to glass cloths, prepregs, printed circuit boards, and the like.

Background

With the recent increase in performance and high-speed communication of information terminals such as smart phones, the printed circuit boards used therein have been remarkably reduced in dielectric constant and dielectric loss tangent while being increased in density and extremely thin.

As an insulating material for the printed wiring board, a laminate obtained by laminating prepregs obtained by impregnating glass cloth with a thermosetting resin such as an epoxy resin (hereinafter referred to as "matrix resin") and curing the prepreg under heat and pressure is widely used. The dielectric constant of the matrix resin used in the high-speed communication substrate is about 3, whereas the dielectric constant of a general E-glass cloth is about 6.7, and the problem of high dielectric constant at the time of lamination becomes more remarkable. It should be noted that the transmission loss of the known signal is shown in the formula Edward a.wolff:

transmission loss ≡ε × tan δ

The smaller the dielectric constant (epsilon) and dielectric loss tangent (tan delta) of the material, the more improved the transmission loss. Accordingly, low dielectric constant glass cloths formed of D glass, NE glass, L glass, and the like having a glass composition different from that of E glass have been proposed (for example, see patent documents 1 to 4).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 5-170483

Patent document 2: japanese patent laid-open No. 2009-263569

Patent document 3: japanese patent laid-open No. 2009-19150

Patent document 4: japanese patent laid-open No. 2009-263824

Disclosure of Invention

Problems to be solved by the invention

Conventionally, in a surface treatment process for glass cloth production or a resin coating process for prepreg production, breakage may occur when pressure is applied in the thickness direction of the glass cloth in order to scrape off excess treatment liquid or resin. Regarding the occurrence of breakage, improvement is attempted by reducing the tension in the longitudinal direction (MD) or the pressure in the thickness direction (drawing pressure) of the glass cloth in the surface treatment step.

However, in recent years, with the increasing demand for low dielectric constant glass cloths or ultra-thin glass cloths having low strength, the frequency of occurrence of breakage of glass cloths has further increased. Even if the MD tension or the pressure in the thickness direction is reduced as in the prior art, it is impossible to reduce the thickness and suppress breakage of the glass cloth having a low dielectric constant.

Accordingly, an object of the present invention is to suppress breakage occurring in a surface treatment step and/or a prepreg manufacturing step and/or reduce the occurrence frequency of breakage with respect to a glass cloth having a width in a direction (TD) of 90 ° to warp yarn of 1000mm or more and a relative dielectric constant (Dk) of 5.0 or less and a thickness of 35 μm or less.

Solution for solving the problem

The inventors of the present invention have found as a result of intensive studies that: the present invention has been made in view of the above problems, and an object of the present invention is to provide a low-dielectric and extremely thin glass cloth, which can be manufactured by specifying that a part of the warp yarn in the width direction is relaxed when the warp yarn is produced as a woven fabric of the glass cloth, and controlling the relaxation even when the warp yarn tension is set to be uniform in the width direction.

Namely, the present invention is as follows.

(1) A glass cloth comprising a warp yarn and a weft yarn, wherein the glass yarn is formed of a plurality of glass filaments, the width of the glass yarn in a direction (TD) at 90 DEG to the warp yarn is 1000mm or more, the glass cloth has a relative dielectric constant (Dk) of 5.0 or less and a thickness of 35 [ mu ] m or less, and the amount of relaxation in the vertical direction when the tension in the direction (MD) parallel to the warp yarn is 50N is 10mm/m or less.

(2) The glass cloth according to item (1), wherein the ratio of the center warp tension to the end warp tension (center warp tension/end warp tension) of the glass cloth is 0.8 or more and 1.2 or less.

(3) The glass cloth according to item (1) or (2), wherein a difference in winding hardness between a central portion and an end portion of the glass cloth is 10 or less in a state of a wound body obtained by winding the glass cloth in a width of 1.3m by 1000 m.

(4) The glass cloth according to any one of items (1) to (3), wherein a difference in a slope of a stress-strain curve in a direction (MD) parallel with the warp yarns at a central portion and an end portion of the glass cloth is 10% or less.

(5) The glass cloth according to any one of items (1) to (4), wherein the weft yarn has a skew amount of 10mm or less.

(6) The glass cloth according to any one of items (1) to (5), wherein the glass cloth has a thickness of 25 μm or less.

(7) The glass cloth according to any one of items (1) to (6), wherein the glass cloth has a thickness of 17 μm or less.

(8) The glass cloth according to any one of items (1) to (7), wherein a tensile strength in a direction (MD) parallel to the warp yarn is 150N/25mm or less.

(9) The glass cloth according to any one of items (1) to (8)Wherein the unit bending stiffness in The Direction (TD) of 90 DEG to the warp yarn is 0.03gf cm ² And/cm or less.

(10) The glass cloth according to any one of items (1) to (9), wherein a width of the glass cloth in a direction (TD) of 90 ° with respect to the warp yarn is 2000mm or less.

(11) The glass cloth according to any one of items (1) to (10), wherein the relaxation amount is 6mm/m or less.

(12) The glass cloth according to item (11), wherein the relaxation amount is 4mm/m or less.

(13) The glass cloth according to item (12), wherein the relaxation amount is 2mm/m or less.

(14) A prepreg, comprising:

the glass cloth according to any one of items (1) to (13); and

and a matrix resin impregnated in the glass cloth.

(15) A printed circuit board comprising the prepreg of item (14).

(16) A glass cloth roll comprises a core tube and glass cloth wound on the core tube,

the glass cloth is formed by using glass yarns formed by a plurality of glass filaments as warp yarns and weft yarns, and

the difference in winding hardness between the center and the end of the glass cloth was 10 or less in a state where the glass cloth was wound 1000m over an acrylonitrile-butadiene-styrene copolymer (ABS) core tube having a core tube diameter of 200mm with a width of 1.3 m.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, when a low dielectric and extremely thin glass cloth is supplied to a surface treatment step and/or a prepreg manufacturing step, breakage of the glass cloth can be suppressed or the frequency of breakage can be reduced.

Drawings

Fig. 1 is a schematic diagram for explaining a method of measuring a slack amount, and is a side view (a) and a top view (b) of a glass cloth provided on a pair of rolls.

Fig. 2 is a schematic diagram showing one form of the glass cloth in the weft skew measurement, and is a diagram showing one form of the weft yarn.

Fig. 3 is a schematic diagram showing one form of the glass cloth in the weft skew amount measurement, and is a diagram showing one form of the weft yarn.

Fig. 4 is a schematic diagram showing one form of the glass cloth in the weft skew amount measurement, and is a diagram showing one form of the weft yarn.

Detailed Description

Hereinafter, embodiments of the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited thereto, and various modifications may be made without departing from the spirit thereof.

[ glass cloth ]

In general, glass cloth is configured by weaving glass yarns formed of a plurality of glass filaments as warp yarns and weft yarns.

In the present specification, the Machine Direction (MD) is a direction parallel to warp yarns provided in a weaving process, the width direction (TD) is a direction 90 ° to the MD in a woven glass cloth cover, and the z-direction is a direction perpendicular to the glass cloth cover composed of the MD and the TD.

The glass cloth according to the present embodiment has a relative dielectric constant (Dk) of 5.0 or less and a thickness of 35 μm or less. In the present specification, unless otherwise specified, the relative permittivity (Dk) refers to the relative permittivity (Dk) at a frequency of 10 GHz. The relative dielectric constant and thickness were measured by the methods described in the examples.

The glass cloth according to the present embodiment preferably has a relative dielectric constant of 4.7 or less, more preferably 3.8 or less or 3.7 or less. The lower limit value of the relative dielectric constant may exceed 0, for example.

The thickness of the glass cloth according to the present embodiment is 35 μm or less, preferably 30 μm or less, more preferably 25 μm or less or 20 μm or less, and even more preferably 17 μm or less or 15 μm or less, from the viewpoint of extremely thinning the prepreg and the substrate, when measured in the z direction by the method described in the example. It is apparent that the lower limit of the thickness exceeds 0 μm, and may be 1 μm or more from the viewpoint of suppressing the occurrence of breakage, the diameter of the glass yarn, and the fiber opening step.

The glass cloth according to the present embodiment has a TD width of 1000mm or more, and is characterized by a relaxation amount measured under specific conditions as shown below. The upper limit value of the width of the TD of the glass cloth may be determined according to the type or size of the loom, and may be, for example, 2000mm or less, 1500mm or less, 1400mm or less, 1300mm or less, or 1200mm or less.

[ relaxation amount ]

In the glass cloth according to the present embodiment, the width of the warp yarn in The Direction (TD) of 90 ° is 1000mm or more, and the z-direction relaxation amount when the tension in the direction (MD) parallel to the warp yarn is set to 50N is 10mm/m or less. The amount of relaxation was measured by the method described in the examples with reference to fig. 1. It has been found that: in a process for producing a glass cloth having a Dk of 5.0 or less and a thickness of 35 [ mu ] m or less, focusing on a surface treatment step and a prepreg production step, the end portion (2) tends to be more relaxed than the central portion of the glass cloth, and when an external force is applied in the thickness (z) direction, the relaxed portion (3) tends to be wrinkled and broken. It was also found that: this tendency is remarkable in low dielectric glasses such as L glass and Q glass. The portion from both ends to 20% of the entire length (t) of the glass cloth in the width direction (TD) is referred to as a glass cloth end portion (2), and the portion of the glass cloth other than the end portion is referred to as a central portion. As described above, the overall length t of the width shown in FIG. 1 is 1000mm or more.

It can be seen that: in consideration of the tendency of breakage described above, the occurrence of breakage in the surface treatment step and the prepreg manufacturing step can be suppressed and the occurrence frequency can be reduced by reducing the amount of relaxation (maximum value of x in fig. 1 a) of the glass cloth (1). Specifically, when the amount of relaxation of the glass cloth is adjusted to a range of 10mm/m or less, the occurrence frequency can be reduced by about 80% as compared with a glass cloth having a relaxation amount exceeding 10 mm/m. From this viewpoint, the amount of relaxation of the glass cloth is 10mm/m or less, preferably 6mm/m or less or 5mm/m or less, more preferably 4mm/m or less or 3mm/m or less, and still more preferably 2mm/m or less or 1mm/m or less.

In consideration of the gravity, it is clear that the lower limit value of the relaxation amount of the glass cloth exceeds 0mm/m, and for example, may be 0.1mm/m or more. As means for controlling the amount of relaxation to a range of 10mm/m or less, for example, there may be mentioned a method of keeping the warp tension in the TD direction uniform, specifically, a method of keeping the ratio of the warp tension in the central portion to the warp tension in the end portion of the glass cloth described above to 1.2 or less (specifically, for preventing the end portion from relaxing, for example, the central portion warp tension/end portion warp tension is 1.2 or the central portion warp tension/end portion warp tension <1.2, preferably 0.8 or less, the central portion warp tension/end portion warp tension is 1.2 or less, more preferably 0.8 or less, the central portion warp tension/end portion warp tension is 1.2 or less, and further preferably 0.8 or less. Further, by keeping the warp tension in the TD uniform, not only the relaxation of the end portions of the glass cloth but also the relaxation of the central portion can be suppressed.

The ratio of the warp tension at the center portion of the glass cloth to the warp tension at the end portion can be measured by measuring the total warp tension and determining the difference between the average warp tension at the end portion and the average warp tension at the center portion. Specifically, the measurement can be performed by the method described in the examples.

As means for adjusting the ratio of the warp tension at the center portion of the glass cloth to the warp tension at the end portion to the above range, for example, the yarn feeding tension at the end portion and the center portion of the glass cloth is changed.

The portion from both ends to 20% of the entire length (t) of the glass cloth in the width direction (TD) is referred to as an end portion of the glass cloth, and the portion of the glass cloth other than the end portion is referred to as a central portion.

[ winding Property ]

In the glass cloth according to the present embodiment, in a state of a wound body obtained by winding the glass cloth around a width of 1.3m by 1000m, a difference in winding hardness between a central portion and an end portion of the glass cloth is preferably 10 or less. The winding hardness difference was measured by the method described in the examples.

When the winding hardness difference is in the range of 10 or less, the frequency of occurrence of breakage of the glass cloth in the surface treatment step and the prepreg manufacturing step tends to be reduced. From this viewpoint, the winding hardness difference is more preferably 8 or less, and still more preferably 6 or less. It is obvious that the lower limit value of the winding hardness difference exceeds 0, and may be 1 or more or 2 or more, for example.

For example, the difference in winding hardness can be adjusted to a range of 10 or less by making the bottom weft yarn of the loom finer than the yarn used for the warp yarn, specifically, by weaving such that the ratio of the TEX of the warp yarn to the TEX of the bottom weft yarn exceeds 1 (i.e., warp TEX/bottom weft TEX > 1).

[ S-S curve characteristic ]

The difference in slope of the stress-strain curve (S-S curve) in the direction (MD) parallel to the warp yarn is preferably 10% or less at the center and the end of the glass cloth according to the present embodiment. The S-S curve and slope of MD of the glass cloth were measured by the methods described in examples.

In the S-S curve of the MD of the glass cloth, if the difference between the slope of the central portion of the glass cloth and the slope of the end portions of the glass cloth is 10% or less, the frequency of occurrence of breakage of the glass cloth in the surface treatment step and the prepreg manufacturing step tends to be reduced. From this viewpoint, the slope difference of the S-S curve of MD is more preferably 5% or less, still more preferably 3% or less, still more preferably 1% or less. It is apparent that the lower limit value of the slope difference of the S-S curve of MD exceeds 0%.

The difference in slope of the S-S curve of the MD can be adjusted to a range of 10% or less by, for example, uniformly opening the glass cloth along the TD in the opening step, and reducing the yarn width difference between the center portion and the end portions of the glass cloth. Specifically, in the fiber opening process, the ratio of the water pressure of the center portion of the glass cloth to the water pressure of the end portions of the glass cloth may be adjusted to be less than 1.2 (i.e., center portion fiber opening water pressure/end portion fiber opening water pressure < 1.2).

The constituent elements of the glass cloth according to the present embodiment will be described below.

[ glass species ]

As long as the relaxation amount of the obtained glass cloth is within the numerical range described above, the glass type of the glass filaments constituting the glass yarn may be at least 1 selected from the group consisting of D glass, NE glass, L glass, NL glass, L2 glass, and Q glass. From the viewpoints of low dielectric constant, relaxation amount, and suppression of breakage, it is preferable to use L glass, NL glass, L2 glass, or Q glass.

[ glass filament composition ]

The glass filaments may have SiO ₂ May also have SiO-removed composition ₂ Other than, or in addition to, siO ₂ Has other compositions based on the above. The other composition is not particularly limited, and examples thereof include Al ₂ O ₃ 、CaO、MgO、B ₂ O ₃ 、TiO ₂ 、Na ₂ O、K ₂ O、Sr ₂ O ₃ 、Fe ₂ O ₃ Etc. The composition can be adjusted according to the amount of raw materials used to make the glass filaments. From the standpoint of adjusting the CTE to be low, siO ₂ The content is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 95% by mass or more, and particularly preferably 99% by mass or more.

[ average filament diameter of glass filaments ]

The average filament diameter of the glass filaments constituting the glass yarn is preferably 2 μm to 10 μm, more preferably 3.5 μm to 8 μm, and even more preferably 4 μm to 6 μm. By setting the average filament diameter of the glass filaments to 2 μm or more, yarn breakage due to tension or processing pressure applied to the glass filaments in the weaving step, the washing step, and the opening step is less likely to occur, and fuzzing can be suppressed. Further, by adjusting the average filament diameters of the warp yarn and the weft yarn to 10 μm or less, the thickness of the glass cloth can be reduced, and a substrate having a small thickness can be obtained. The tension and the processing pressure in the weaving process, the washing process and the opening process can be suppressed, and the glass cloth which is thin and has suppressed fuzzing can be realized. In particular, by adjusting the average filament diameter of the glass filaments to be in the range of 4 μm to 6 μm, the thickness deviation of the glass cloth is suppressed.

[ number of glass filaments ]

The number of glass filaments constituting the glass yarn is preferably 30 to 200, more preferably 40 to 100. By setting the number of glass filaments in the above range, tension and processing pressure can be suppressed in the weaving step, the washing step, or the opening step, and fuzzing can be suppressed.

[ weft skew amount ]

The weft yarn constituting the glass cloth according to the present embodiment is preferably (15/1000) =0.015 mm/width (mm), or has a skew amount of 0.015 mm/width (mm) or less. In the present specification, the skew amount means Z defined by the following formula (I) _N (Z ₀ 、Z ₁ And Z ₂ ) The maximum value among them.

Z _N ＝|(Y _N+1 -Y _N )/(X _N+1 -X _N )|(I)

In the formula { formula, N is 0 to 2, X _N+1 -X _N When the value of (2) is 0, Z _N Is 0.}

In the formula (I), X ₀ ～X ₃ And Y ₀ ～Y ₃ With (X) ₀ ，Y ₀ )、(X ₁ ，Y ₁ )、(X ₂ ，Y ₂ ) And (X) ₃ ，Y ₃ ) Is expressed as a combination of (a) and (b), and is defined as follows.

A glass cloth, prepreg, or printed circuit board formed of a plurality of warp yarns and a plurality of weft yarns is used as a sample to be tested, the warp yarn direction of the sample to be tested is defined as the Y direction, the direction perpendicular to the Y direction is defined as the X direction, and the weft yarns extending from the first warp yarn to the second warp yarn among the first warp yarn and the second warp yarn positioned at both ends of the sample to be tested define a point of origin (0, 0), that is, (X) ₀ ，Y ₀ ) And the Y-axis and the X-axis of (c). In addition, the junction between the second warp yarn and the weft yarn is set as the end point (X ₃ ，Y ₃ ) Regarding the coordinates Y of the weft yarn on the X-axis and the Y-axis, one of points exhibiting the maximum value and the minimum value is set as (X) ₁ ，Y ₁ ) The other is set as (X) ₂ ，Y ₂ ) In this case, the weft yarns are sequentially arranged (X ₀ ，Y ₀ )、(X ₁ ，Y ₁ )、(X ₂ ，Y ₂ ) And (X) ₃ ，Y ₃ )。

Hereinafter, referring to fig. 2 to 4, Z is exemplarily shown ₀ 、Z ₁ And Z ₂ Is a calculation method of (a). Fig. 2 to 4 are schematic views showing one form of weft yarn. The form of the weft yarn in the present embodiment is not limited to the form of the weft yarn in fig. 2 to 4.

In FIG. 2, origins (X ₀ ，Y ₀ ) Point exhibiting maximum value of Y (X ₁ ，Y ₁ ) A point (X) exhibiting the minimum value of Y ₂ ，Y ₂ ) And endpoint (X) ₃ ，Y ₃ )。Z ₀ By combining two adjacent points (X ₀ ，Y ₀ ) And (X) ₁ ，Y ₁ ) Substituting into the formula (I) to calculate Z ₁ By combining two adjacent points (X ₁ ，Y ₁ ) And (X) ₂ ，Y ₂ ) Substituting into the formula (I) to calculate Z ₂ By combining two adjacent points (X ₂ ，Y ₂ ) And (X) ₃ ，Y ₃ ) Substituting the calculated value into the formula (I).

In FIG. 3, origins (X) ₀ ，Y ₀ ) Point exhibiting maximum value of Y (X ₁ ，Y ₁ ) A point (X) exhibiting the minimum value of Y ₂ ，Y ₂ ) And endpoint (X) ₃ ，Y ₃ ) Here, (X) ₂ ，Y ₂ ) And (X) ₃ ，Y ₃ ) Representing the same coordinate. Z is Z ₀ 、Z ₁ And Z ₂ The calculation can be performed in the same manner as described above with reference to fig. 2.

The term (X) ₂ ，Y ₂ ) And (X) ₃ ，Y ₃ ) Representing the same coordinate, and therefore, Z ₂ The value of 0 is used in the above formula (I).

In FIG. 4, origins (X ₀ ，Y ₀ ) Point exhibiting maximum value of Y (X ₁ ，Y ₁ ) A point (X) exhibiting the minimum value of Y ₂ ，Y ₂ ) And endpoint (X) ₃ ，Y ₃ ) Here, (X) ₀ ，Y ₀ ) And (X) ₁ ，Y ₁ ) Represents the same coordinate, and (X) ₂ ，Y ₂ ) And (X) ₃ ，Y ₃ ) Representing the same coordinate, Z ₀ 、Z ₁ And Z ₂ The calculation can be performed in the same manner as described above with reference to fig. 2.

The term (X) ₀ ，Y ₀ ) And (X) ₁ ，Y ₁ ) Representing the same coordinate, and therefore, Z ₀ In the above formula (I), a value of 0, Z ₂ A value of 0 is also used.

In the present specification, the maximum value of the skew measurement value is referred to as the skew amount in the present embodiment. The skew amount was measured in accordance with JIS L1096 by the method described in the examples.

If the weft skew amount of the weft yarn is in the range of 15mm or less, breakage in the surface treatment step and the prepreg manufacturing step can be suppressed or prevented even if the glass cloth has a Dk of 5.0 or less and a thickness of 35 μm or less. From this viewpoint, the skew amount of the weft yarn is more preferably 10mm or less, still more preferably 5mm or less, still more preferably 3mm or less. The lower limit value of the weft skew amount of the weft yarn may be 0mm or more than 0mm.

For example, by increasing the opening tension in the opening step of producing the glass cloth, specifically, by opening the glass cloth so that the ratio of the opening tension to the tensile strength of the glass cloth exceeds 0.1 (i.e., the opening tension/tensile strength > 0.1), the weft skew amount of the weft yarn can be adjusted to a range of 15mm or less.

[ tensile Strength ]

The tensile strength of the glass cloth is preferably 150N/25mm or less in the direction (MD) parallel to the warp yarns. When the MD tensile strength is in the range of 150N/25mm or less, breakage is generally liable to occur in the surface treatment step and the prepreg production step, and breakage can be significantly suppressed or prevented by setting the relaxation amount to 10mm/m or less. From this viewpoint, the MD tensile strength is more preferably 100N/25mm or less, and still more preferably 50N/25mm or less.

It is apparent that the lower limit value of the MD tensile strength of the glass cloth exceeds 0N/25mm, and is preferably 20N/25mm or more from the viewpoint of improving insulation reliability in the thickness (T) direction of the substrate including the glass cloth. The tensile strength of the glass cloth can be measured in accordance with item 7.4 of JIS R3420.

[ unit bending stiffness (texture) ]

The glass cloth preferably has a unit bending stiffness of 0.03gf cm in a direction (TD) of 90 DEG with respect to the warp yarn ² And/cm or less. The bending stiffness models the action of bending a molded body such as a glass cloth, and is used as an index of texture. In the art, bending rigidity may reflect rigidity among textures of glass cloths, and the like.

If the unit bending stiffness of the glass cloth is 0.03gf cm ² In the range of not more than/cm, breakage is generally liable to occur in the surface treatment step and the prepreg production step, and breakage can be significantly suppressed or prevented by setting the relaxation amount to not more than 10 mm/m. From this viewpoint, the unit bending stiffness is more preferably 0.02gf cm ² Preferably less than or equal to/cm, more preferably 0.01gf cm ² And/cm or less. In addition, the unit bending stiffness can be arbitrarily set according to the dimensional stability of the glass cloth, and for example, can exceed 0gf cm ² /cm. The unit bending stiffness (texture) of the glass cloth was measured by the method described in examples.

[ beating-up Density ]

The weft densities of warp yarns and weft yarns constituting the glass cloth are each independently preferably 50 to 140 yarns/inch, more preferably 80 to 130 yarns/inch.

[ weight of cloth (weight per unit area) ]

The cloth weight (weight per unit area) of the glass cloth is preferably 4 to 200g/m ² More preferably 10 to 100g/m ² More preferably 10 to 60g/m ² 。

[ weaving Structure ]

The woven structure of the glass cloth is not particularly limited, and examples thereof include a woven structure such as a plain weave, a basket weave, a satin weave, and a twill weave. Among them, a plain weave structure is preferable.

[ surface treatment ]

Preferably, it is: the glass yarn (including glass filaments) of the glass cloth is surface-treated with a silane coupling agent, preferably a silane coupling agent having an unsaturated double bond group (hereinafter also simply referred to as "silane coupling agent"). When a silane coupling agent having an unsaturated double bond group is used, the reactivity with the matrix resin is further improved, and further, the hydrophilic functional group is less likely to be formed after the reaction with the matrix resin, thereby further improving the insulation reliability.

The silane coupling agent having an unsaturated double bond group is not particularly limited, and examples thereof include compounds represented by the following general formula (1). By using such a silane coupling agent, moisture absorption resistance is further improved, and as a result, insulation reliability tends to be further improved. In particular, siO can be improved by using a silane coupling agent having an unsaturated double bond group ₂ Plating solution dip dyeing property, insulation reliability and fuzzing quality of glass cloth with the composition of 98-100 mass percent after drilling processing.

X(R) _3-n SiY _n ···(1)

(wherein X is an organofunctional group having 1 or more groups selected from at least any one of an amino group and an unsaturated double bond group, Y is each independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is each independently a group selected from the group consisting of a methyl group, an ethyl group and a phenyl group.)

In the general formula (1), X is an organic functional group having 1 or more at least any one selected from amino groups and unsaturated double bond groups, more preferably 3 or more organic functional groups, and still more preferably 4 or more organic functional groups selected from at least any one selected from amino groups and unsaturated double bond groups. By setting X as such a functional group, the moisture absorption resistance tends to be further improved. The organic functional group having 1 or more unsaturated double bond groups represented by X is not particularly limited, and examples thereof include vinyl, allyl, vinylidene, acryloyloxy, and methacryloyloxy.

The alkoxy group in the above general formula (1) may be used in any form, but is preferably an alkoxy group having 5 or less carbon atoms for stabilizing the glass cloth.

The silane coupling agent that can be specifically used is not particularly limited, and examples thereof include known materials such as N- β - (N-vinylbenzyl aminoethyl) - γ -aminopropyl trimethoxysilane and its hydrochloride, N- β - (N-vinylbenzyl aminoethyl) - γ -aminopropyl methyldimethoxysilane and its hydrochloride, N- β - (N-bis (vinylbenzyl) aminoethyl) - γ -aminopropyl trimethoxysilane and its hydrochloride, N- β - (N-bis (vinylbenzyl) aminoethyl) -N- γ - (N-vinylbenzyl) - γ -aminopropyl trimethoxysilane and its hydrochloride, aminopropyl trimethoxysilane, vinyltrimethoxysilane, methacryloxypropyl trimethoxysilane, methacryloxyoctyl trimethoxysilane, acryloxypropyl trimethoxysilane, and the like. The silane coupling agent tends to have excellent reactivity with a glass yarn (glass filament) of a glass cloth or a matrix resin of a substrate, particularly a radical polymerization resin. Therefore, there is a tendency that: the silane coupling agent can suppress a decrease in insulation reliability due to the resin and glass cloth being easily peeled off at the interface, and can suppress a decrease in insulation reliability due to the plating solution being impregnated into the glass cloth.

[ count ]

From the viewpoint of thinning the glass cloth and the viewpoint of controlling the difference in winding hardness between the central portion and the end portions, the counts of warp yarns and weft yarns (hereinafter also referred to as Tex) constituting the glass cloth are each independently preferably 0.2g/1000m or more and 20.0g/1000m or less, more preferably 0.5g/1000m or more and 10.0g/1000m or less. Tex of the glass cloth can be calculated by the following formula.

Tex＝m/l×1000

In the formula { Tex: count number

m: quality of test piece (g)

l: length of test piece (m) }

[ method for producing glass cloth ]

The method for producing the glass cloth according to the present embodiment is not particularly limited, and examples thereof include a method having the following steps: a covering step of covering the surface of the glass filaments almost completely with a silane coupling agent by using a treatment liquid having a concentration of 0.1 to 3.0 wt%; and a fixing step of fixing the silane coupling agent to the surface of the glass filaments by heat drying.

The method for manufacturing a glass cloth according to the present embodiment may include: and a step of adjusting the amount of the silane coupling agent attached by cleaning at least a part of the silane coupling agent fixed to the surface of the glass filaments with high-pressure spray water or the like.

As a solvent for dissolving or dispersing the silane coupling agent, water or an organic solvent can be used, but from the viewpoint of safety and global environment protection, water is preferable as a main solvent. The method for obtaining the treatment liquid containing water as the main solvent is preferably any of a method in which the silane coupling agent is directly put into water and a method in which the silane coupling agent is dissolved in a water-soluble organic solvent to prepare an organic solvent solution and then the organic solvent solution is put into water. In order to improve the water dispersibility and stability of the silane coupling agent in the treatment liquid, a surfactant may be used in combination.

The glass cloth is preferably subjected to a covering step, a fixing step, and an adjusting step after the weaving step. Further, if necessary, the method may further include a fiber opening step of opening glass yarns of the glass cloth after the weaving step. When the adjustment step is performed after the weaving step, the adjustment step may also serve as the opening step. The composition of the glass cloth is generally unchanged before and after the fiber opening.

It can be considered that: by the above-described production method, the silane coupling agent layer can be formed almost completely and uniformly on the entire surface of each 1 glass filament constituting the glass yarn.

As a method of applying the treatment liquid to the glass cloth, the following method can be used: (A) A method of immersing and passing a glass cloth (hereinafter referred to as "immersion method") by accumulating a treatment liquid in a bath; (B) A method of directly coating the treatment liquid on the glass cloth by using a roll coater, a die coater, a gravure coater, or the like. When the coating is performed by the dipping method of (a), the dipping time of the glass cloth in the treating liquid is preferably selected to be 0.5 seconds to 1 minute.

The method of applying the treatment liquid to the glass cloth and then heating and drying the solvent includes known methods such as hot air and electromagnetic waves.

In order to sufficiently perform the reaction between the silane coupling agent and the glass, the heating and drying temperature is preferably 90℃or higher, more preferably 100℃or higher. In order to prevent deterioration of the organic functional group of the silane coupling agent, the heating and drying temperature is preferably 300 ℃ or less, more preferably 200 ℃ or less.

The method of opening the glass cloth in the opening step is not particularly limited, and examples thereof include a method of opening the glass cloth with spray water (high-pressure water opening), a vibration washer, ultrasonic water, a calender, and the like. In order to suppress the decrease in tensile strength of the glass cloth caused by the opening process, countermeasures such as low friction of the contact member at the time of weaving the glass yarn, optimization of the bundling agent, and high adhesion are preferably implemented. By reducing the tension applied to the glass cloth during the opening process, the air permeability tends to be further reduced.

The glass cloth manufacturing method may have an optional step after the opening step. The optional step is not particularly limited, and examples thereof include a slit processing step.

After the surface treatment, the glass cloth is coated with a matrix resin to produce a prepreg. The storage period of the glass cloth is preferably 2 years or less until the glass cloth is surface-treated and coated with the matrix resin. The storage temperature is preferably set to 10 to 40 ℃. When the storage temperature is 40 ℃ or lower or 30 ℃ or lower, the deactivation of the unsaturated double bond group of the silane coupling agent on the surface of the glass cloth can be suppressed, and the reactivity with the matrix resin can be maintained. Further, by keeping the storage period within 2 years, the reaction of the silane coupling agents with each other due to water adhering to the glass surface tends to be suppressed, and the bundling property of the glass filament bundles tends to be improved. This tends to improve the permeability of the matrix resin.

[ glass cloth roll ]

In another embodiment of the present invention, a glass cloth roll can be formed, which comprises a core tube made of acrylonitrile-butadiene-styrene copolymer (ABS) having a core tube diameter of 200mm and a glass cloth wound around the core tube. In a state where the glass cloth in the roll is wound on the core tube with a width of 1.3m for 1000m, the difference in winding hardness between the center portion and the end portions of the glass cloth is preferably 10 or less. When the difference in winding hardness between the center portion and the end portion of the glass cloth in the rolled state is 10 or less, the occurrence of breakage can be suppressed or the frequency of occurrence of breakage can be reduced when the glass cloth roll is supplied to the prepreg manufacturing process.

The glass cloth constituting the glass cloth roll is as described above as an embodiment of the glass cloth.

[ prepreg ]

The prepreg of the present embodiment includes the glass cloth and a matrix resin impregnated in the glass cloth. Thus, a prepreg which is thin, has a low dielectric constant, and can improve insulation reliability can be provided.

As the matrix resin, both thermosetting resins and thermoplastic resins can be used. The thermosetting resin is not particularly limited, and examples thereof include: a) An epoxy resin obtained by curing an epoxy group-containing compound by reacting the epoxy group-containing compound with a compound having at least one of an amino group, a phenol group, an acid anhydride group, a hydrazide group, an isocyanate group, a cyanate group, a hydroxyl group, and the like, which can react with the epoxy group, in the absence of a catalyst or by adding a catalyst having a reaction catalytic ability such as an imidazole compound, a tertiary amine compound, a urea compound, and a phosphorus compound; b) A radical polymerization type curable resin in which a compound having at least one of an allyl group, a methacryloyl group, and an acryl group is cured using a thermal decomposition type catalyst or a photo decomposition type catalyst as a reaction initiator; c) A maleimide triazine resin obtained by curing a compound having a cyanate group by reacting the compound with a compound having a maleimide group; d) A thermosetting polyimide resin obtained by reacting a maleimide compound with an amine compound to cure the maleimide compound; e) And benzoxazine resins obtained by crosslinking and curing a compound having a benzoxazine ring by heating and polymerizing.

The thermoplastic resin is not particularly limited, and examples thereof include polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, aromatic polyamide, polyetheretherketone, thermoplastic polyimide, insoluble polyimide, polyamideimide, and fluororesin. In addition, a thermosetting resin may be used in combination with a thermoplastic resin.

[ printed Circuit Board ]

The printed circuit board of the present embodiment has the above prepreg. Thus, a printed circuit board having a low dielectric constant and capable of improving insulation reliability can be provided. The prepreg in the printed wiring board of the present embodiment may be a laminate including 2 or more layers.

Examples

The present invention will be described in more detail with reference to examples and comparative examples. The present invention is not limited at all to the following examples.

Example 1

Glass yarns made of L glass were woven to form glass cloths, and the glass cloths were immersed in a treatment solution in which hydrochloride salt of N-beta- (N-vinylbenzylaminoethyl) -gamma-aminopropyl trimethoxysilane (manufactured by Tolydorning Co., ltd.; Z6032) was dispersed in water, followed by heat drying, as shown in Table 1. Then, high-pressure water was sprayed to open the fiber, and the fiber was heated and dried to obtain a glass cloth product for evaluation.

Examples 2 to 12 and comparative examples 1 to 6

As shown in table 1, a glass cloth product for evaluation was obtained in the same manner as in example 1, except that the glass cloth thickness, glass type, dielectric constant, relaxation property, winding property, and the like were changed.

< method for evaluating thickness of glass cloth >

According to JIS R3420, 7.10, a micrometer was used to rotate the measuring shaft calmly and lightly contact the measuring surface in parallel. The graduation of the ratchet wheel after making 3 sounds is read.

< method for producing substrate >

The polyphenylene ether resin varnish (a mixture of 30 parts by mass of a modified polyphenylene ether resin, 10 parts by mass of triallyl isocyanurate, 60 parts by mass of toluene, and 0.1 part by mass of a catalyst) was impregnated with the above-described compositionThe glass cloth obtained in example/comparative example was dried at 120℃for 2 minutes to obtain a prepreg. The resin content of the prepreg was adjusted to 60% by volume. The prepreg was laminated, and further, copper foil having a thickness of 12 μm was laminated up and down at 200℃and 40kg/cm ² Heating and pressurizing for 60 minutes to obtain a substrate.

< method for measuring/calculating dielectric constant >

In the above-described manner, a substrate was produced so that the resin content of the prepreg was 60% by volume on average 100% by volume, and the copper foil was removed to obtain a sample for evaluating the dielectric constant. The dielectric constant of the obtained sample at a frequency of 10GHz was measured using an impedance analyzer (manufactured by Agilent Technologies Co.). The relative dielectric constant (Dk) of the glass cloth at 10GHz was calculated from the obtained substrate dielectric constant based on the volume fraction of the glass cloth and the resin dielectric constant of 2.5.

< method for measuring center warp tension/end warp tension >

In the weaving step, a low-load digital tensiometer (ZEF-100) manufactured by SCHMIDT corporation was used to measure the tension per 1 warp yarn to 0.1cN unit when the warp yarns were smoothed out. The average warp tension at the portion (end) from both ends up to 20% and the portion (central portion) other than the end were calculated, and the central portion warp tension/end warp tension was obtained.

< measurement of relaxation amount >

As shown in FIG. 1, glass cloth (1) having a width of 1000mm over the entire length t was laid horizontally on two rolls (4, 4) having a roll-to-roll distance of 1m, and when the glass cloth (1) was stretched by holding both MD ends (end 2 in FIG. 1 b) of the glass cloth (1) with a tension of 50N in the MD direction, the most recessed portion of the cloth was visually judged, and the amount of recess in the vertical direction (z direction) of the glass cloth relaxed portion (3) was measured as a relaxed amount (x) until 1mm unit by using a laser displacement meter (LK-G5000) made by Kidney corporation. The amount of the depression is the distance from the plane where the upper surfaces of the two rolls (4, 4) are connected by a straight line to the furthest part of the glass cloth (1).

< winding test >

On an ABS core tube (hardness: 90 or more) having a core tube diameter of 200mm, a glass cloth was wound to a length of 1000m in a width of 1.3m to prepare a wound body.

The difference in winding hardness between the center and the end of the wound body was measured in accordance with JIS K7312 using a winding hardness measuring instrument "GS-701N" manufactured by TECLOCK.

Further, using Autograph "AGS-J5kN" manufactured by shimadzu corporation, the difference in the slope of the stress-strain curve in the direction (MD) parallel to the warp yarn of the glass cloth was measured at the center and the end of the wound body.

< weft skew amount >

The skew amount of the sample was measured in accordance with JIS L1096 with reference to FIGS. 2 to 4. Specifically, 1 weft yarn in a 1000mm wide glass cloth laid on a pair of rolls was visually observed, the displacement amount from the reference line was measured with the TD tangent line between the rolls and the cloth as the reference line, the difference between the maximum value and the minimum value of the displacement amount was calculated as the skew amount, and the operation was performed 5 times to calculate the average value.

< tensile Strength >

The tensile strength of the glass cloth was measured in accordance with item 7.4 of JIS R3420.

< unit bending stiffness (texture) >

Using "KES-FB2-A" manufactured by KATOTECH corporation as a bending tester, the unit bending stiffness (gf cm) of the glass cloth was measured ² /cm)。

< frequency of breakage in surface treatment Process of glass cloth >

In examples and comparative examples, as described above, glass cloths were immersed in a silane coupling agent treatment liquid in which hydrochloride salt of N- β - (N-vinylbenzylaminoethyl) - γ -aminopropyl trimethoxysilane (manufactured by Tolytroning Co., ltd.; Z6032) was dispersed in water, and whether or not the glass cloths were broken when force was applied to the glass cloths in the Z direction by passing the glass cloths through two pairs of rollers to scrape off excess silane coupling agent was observed, and the breakage frequency (%) of the glass cloths relative to the number of N was calculated.

< frequency of breakage in prepreg production Process >

As described in the above < method for manufacturing a substrate >, the glass cloths obtained in examples and comparative examples were impregnated with a polyphenylene ether resin varnish, and whether or not the prepreg was broken when force was applied to the glass cloths in the Z direction by passing the glass cloths through two pairs of rollers to scrape off excess PPE resin was observed, and the breakage frequency (%) of the prepreg with respect to the number N was calculated.

The evaluation results of the glass cloths shown in examples and comparative examples are summarized in table 1.

[ Table 1-1]

[ tables 1-2]

From the comparison of examples 8 to 9 with comparative examples 5 to 6, it can be seen that: in the comparative examples, breakage occurred as the glass cloth was thinner, but in examples 8 to 9, the effect of the present invention was remarkably exhibited by controlling the amount of relaxation even under the condition that the glass cloth was easily broken.

Description of the reference numerals

1. Glass cloth

2. End of glass cloth

3. Glass cloth relaxation part

4. Roller

x relaxation amount

t width full length

Claims

1. A glass cloth comprising a warp yarn and a weft yarn, wherein the warp yarn is made of glass yarns each of which is formed of a plurality of glass filaments, the width of the glass yarn in a direction (TD) of 90 DEG with respect to the warp yarn is 1000mm or more,

the glass cloth has a relative dielectric constant (Dk) of 5.0 or less and a thickness of 35 [ mu ] m or less, and has a vertical-direction relaxation amount of 10mm/m or less when a tension in a direction (MD) parallel to the warp yarn is set to 50N.

2. The glass cloth according to claim 1, wherein a ratio of a center warp tension to an end warp tension (center warp tension/end warp tension) of the glass cloth is 0.8 or more and 1.2 or less.

3. The glass cloth according to claim 1, wherein a ratio of a center warp tension to an end warp tension (center warp tension/end warp tension) of the glass cloth is 0.8 or more and 1.1 or less.

4. The glass cloth according to claim 1 or 2, wherein a difference in winding hardness between a central portion and an end portion of the glass cloth is 10 or less in a state of a wound body obtained by winding the glass cloth in a width of 1.3m by 1000 m.

5. The glass cloth according to claim 1 or 2, wherein a difference in winding hardness between a central portion and an end portion of the glass cloth is 1 to 8 in a state of a wound body obtained by winding the glass cloth in a width of 1.3m by 1000 m.

6. The glass cloth according to claim 1 or 2, wherein a difference in winding hardness between a central portion and an end portion of the glass cloth is 2 or more and 6 or less in a state of a wound body obtained by winding the glass cloth in a width of 1.3m by 1000 m.

7. The glass cloth according to claim 1 or 2, wherein a difference in slope of stress-strain curves of a central portion and end portions of the glass cloth in a direction (MD) parallel with the warp yarns is 10% or less.

8. The glass cloth according to claim 1 or 2, wherein a difference in slope of stress-strain curves of a central portion and end portions of the glass cloth in a direction (MD) parallel with the warp yarns is 8% or less.

9. The glass cloth according to claim 1 or 2, wherein the weft yarn has a skew amount of 10mm or less.

10. The glass cloth according to claim 1 or 2, wherein the weft yarn has a skew amount of 8mm or less.

11. The glass cloth according to claim 9, wherein the skew amount is Z defined by the following formula (I) _N (Z ₀ 、Z ₁ And Z ₂ ) The maximum value of the above-mentioned materials,

Z _N ＝|(Y _N+1 -Y _N )/(X _N+1 -X _N )|(I)

in the formula (I), N is 0 to 2, X _N+1 -X _N When the value of (2) is 0, Z _N Is 0;

in the formula (I), X ₀ ～X ₃ And Y ₀ ～Y ₃ With (X) ₀ ，Y ₀ )、(X ₁ ，Y ₁ )、(X ₂ ，Y ₂ ) And (X) ₃ ，Y ₃ ) Is expressed by a combination of (a) and (b), is defined as follows,

using a glass cloth as a sample to be tested, defining a warp direction of the sample to be tested as a Y direction and a direction perpendicular to the Y direction as an X direction, and defining a weft extending from a first warp to a second warp among the first warp and the second warp located at both ends of the sample to be tested, wherein a point of contact between the first warp and the weft is defined as an origin (0, 0), that is, (X) ₀ ，Y ₀ ) In addition, the joint of the second warp yarn and the weft yarn is set as the end point (X ₃ ，Y ₃ ) Regarding the coordinates Y of the weft yarn on the X-axis and Y-axis, one of points exhibiting the maximum value and the minimum value is set as (X) ₁ ，Y ₁ ) The other is set as (X) ₂ ，Y ₂ ) In this case, the weft yarns are sequentially arranged (X ₀ ，Y ₀ )、(X ₁ ，Y ₁ )、(X ₂ ，Y ₂ ) And (X) ₃ ，Y ₃ )。

12. The glass cloth according to claim 1 or 2, wherein the glass cloth has a thickness of 30 μm or less.

13. The glass cloth according to claim 1 or 2, wherein the glass cloth has a thickness of 25 μm or less.

14. The glass cloth according to claim 1 or 2, wherein the glass cloth has a thickness of 20 μm or less.

15. The glass cloth according to claim 1 or 2, wherein the glass cloth has a thickness of 17 μm or less.

16. The glass cloth according to claim 1 or 2, wherein the glass cloth has a thickness of 15 μm or less.

17. Glass cloth according to claim 1 or 2, wherein the tensile strength in the direction (MD) parallel to the warp yarns is 150N/25mm or less.

18. The glass cloth according to claim 1 or 2, wherein the unit bending stiffness in The Direction (TD) of 90 ° to the warp yarn is 0.03 gf-cm ² And/cm or less.

19. The glass cloth according to claim 1 or 2, wherein the width of the glass cloth in a direction (TD) of 90 ° to the warp yarn is 2000mm or less.

20. The glass cloth according to claim 1 or 2, wherein the amount of relaxation is 6mm/m or less.

21. The glass cloth of claim 20, wherein the amount of relaxation is 4mm/m or less.

22. The glass cloth of claim 20, wherein the amount of relaxation is 3mm/m or less.

23. The glass cloth of claim 20, wherein the amount of relaxation is 2mm/m or less.

24. The glass cloth of claim 20, wherein the amount of relaxation is 1mm/m or less.

25. A prepreg, comprising:

the glass cloth of any one of claims 1 to 24; and

and (3) impregnating the glass cloth with a matrix resin.

26. A printed circuit board comprising the prepreg of claim 25.

27. A glass cloth roll comprising a core tube and the glass cloth of any one of claims 1 to 24 wound around the core tube,