CN114207203A

CN114207203A - Glass cloth, prepreg and printed circuit board

Info

Publication number: CN114207203A
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: 2022-03-18
Anticipated expiration: 2040-12-03
Also published as: TW202142750A; JP7371122B2; KR20220037515A; JPWO2021124913A1; WO2021124913A1; TWI827895B; KR102633930B1; CN114207203B

Abstract

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

Description

Glass cloth, prepreg and printed circuit board

Technical Field

The present invention relates to a glass cloth, a prepreg, a printed wiring board, and the like.

Background

With the recent trend toward higher performance and higher speed communication of information terminals such as smartphones, printed circuit boards used therein have been made to have higher density and thinner thickness, and have been made to have a lower dielectric constant and a lower dielectric loss tangent.

As an insulating material for such a printed wiring board, a laminate board obtained by laminating prepregs obtained by impregnating a glass cloth with a thermosetting resin such as an epoxy resin (hereinafter referred to as a "matrix resin") and curing the prepregs by heating and pressing is widely used. While the dielectric constant of the matrix resin used for the high-speed communication substrate is about 3, 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 obvious. It should be noted that the transmission loss of the known signal is shown by Edward a. wolff formula:

transmission loss ∈ tan δ

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

Documents of the prior art

Patent document

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

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

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

Patent document 4: japanese laid-open patent publication 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 application process for prepreg production, when pressure is applied in the thickness direction of the glass cloth in order to scrape off excess treatment liquid or resin, breakage may occur. As for the occurrence of breakage, attempts have been made to improve the breakage 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 cloth or ultra-thin glass cloth having low strength, the frequency of breakage of the glass cloth has further increased. Even if the MD tension or the pressure in the thickness direction is reduced as in the conventional art, it is impossible to make the glass cloth thinner than the conventional one and to suppress the 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 process and/or a prepreg manufacturing process and/or reduce the frequency of breakage, with respect to a glass cloth having a width in a direction (TD) at 90 ° to a warp yarn of 1000mm or more, a relative dielectric constant (Dk) of 5.0 or less, and a thickness of 35 μm or less.

Means for solving the problems

The inventors of the present invention have conducted extensive studies and found that: the present inventors have found that the above-described problems can be solved by determining that slack is generated in a part in the width direction when producing a woven fabric as a glass cloth, even when the tension of warp yarns is set to be uniform in the width direction, and controlling the slack, thereby completing the present invention.

That is, the present invention is as follows.

(1) A glass cloth comprising glass yarns formed of a plurality of glass filaments as warp yarns and weft yarns, wherein the width in a direction (TD) at 90 DEG to the warp yarns 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 vertical relaxation is 10mm/m or less when the tension in a direction (MD) parallel to the warp yarns is set to 50N.

(2) The glass cloth according to item (1), wherein a 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 the 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 1000m of the glass cloth having a width of 1.3 m.

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

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

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

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

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

(9) The glass cloth according to any one of items (1) to (8), wherein a unit bending rigidity in a direction (TD) of 90 ° to the warp is 0.03gf cm²Less than/cm.

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

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

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

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

(14) A prepreg, comprising:

the glass cloth according to any one of items (1) to (13); 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 composed of glass yarns formed by a plurality of glass filaments as warp yarns and weft yarns, and

when the glass cloth is wound on a core tube made of acrylonitrile-butadiene-styrene copolymer (ABS) with a core tube diameter of 200mm for 1000m at a width of 1.3m, the difference in winding hardness between the central part and the end part of the glass cloth is 10 or less.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, when a glass cloth having a low dielectric property and an extremely thin thickness is subjected to a surface treatment step and/or a prepreg manufacturing step, it is possible to suppress the occurrence of breakage of the glass cloth or reduce the frequency of occurrence of breakage.

Drawings

Fig. 1 is a schematic diagram for explaining a method of measuring a sag, and is a side view (a) and a plan view (b) of a glass cloth set on a pair of rolls.

Fig. 2 is a schematic view showing one form of a glass cloth in skewness measurement, and is a view showing one form of a weft.

Fig. 3 is a schematic view showing one form of a glass cloth in skewness measurement, and is a view showing one form of a weft.

Fig. 4 is a schematic view showing one form of a glass cloth in skewness measurement, and is a view showing one form of a weft.

Detailed Description

The following describes an embodiment of the present invention (hereinafter referred to as "the present embodiment") in detail, but the present invention is not limited thereto, and various modifications can be made within the scope not departing from the gist thereof.

[ glass cloth ]

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

In this specification, the Machine Direction (MD) is a direction parallel to warp yarns set in a weaving process, the width direction (TD) is a direction forming 90 ° with the MD in a woven glass cloth surface, and the z direction is a direction perpendicular to the glass cloth surface composed of the MD and 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, the relative permittivity (Dk) refers to the relative permittivity (Dk) at a frequency of 10GHz, unless otherwise specified. The relative dielectric constant and the thickness were measured by the methods described in 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 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, and is preferably 30 μm or less, more preferably 25 μm or less or 20 μm or less, and further 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 examples. It is obvious that the lower limit of the thickness is more than 0 μm, and it may be 1 μm or more from the viewpoint of suppressing the occurrence of breakage, the diameter of the glass yarn, and the opening step.

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

[ amount of relaxation ]

In the glass cloth according to the present embodiment, the width in The Direction (TD) at 90 DEG to the warp is 1000mm or more, and the amount of slack in the z direction when the tension in the direction (MD) parallel to the warp 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 the manufacturing process of the glass cloth with the Dk of 5.0 or less and the thickness of 35 μm or less, when the surface treatment process and the prepreg manufacturing process are focused, the end part (2) is more likely to be loosened than the central part of the glass cloth, and when an external force is applied to the thickness (z) direction, the loosened part (3) tends to be wrinkled and damaged. It has also been found that: this tendency is remarkable in low dielectric glass such as L glass and Q glass. In addition, with respect to the entire length (t) of the glass cloth in the width direction (TD), a portion from both ends to 20% is referred to as a glass cloth end portion (2), and a portion of the glass cloth other than the end portion is referred to as a central portion. As described above, the entire width t shown in FIG. 1 is 1000mm or more.

Therefore, the following steps are carried out: in consideration of the above-described tendency of occurrence of breakage, the amount of slack (the maximum value of x in fig. 1 a) of the glass cloth (1) is reduced, whereby the occurrence of breakage in the surface treatment step and the prepreg production step can be suppressed, and the frequency of occurrence can be reduced. Specifically, when the amount of slack in the glass cloth is adjusted to be within a range of 10mm/m or less, the frequency of occurrence can be reduced by about 80% as compared with a glass cloth having an amount of slack exceeding 10 mm/m. From this viewpoint, the amount of slack 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.

When gravity is taken into consideration, it is clear that the lower limit value of the amount of slack of the glass cloth exceeds 0mm/m, and may be 0.1mm/m or more, for example. Examples of means for controlling the slack amount to be in the range of 10mm/m or less include, for example, keeping the warp tension in the TD uniform, specifically, making the ratio of the tension of the warp in the center portion to the tension of the warp in the end portion of the glass cloth described above to be 1.2 or less than 1.2 (specifically, in order not to slacken the end portion, for example, the center portion warp tension/the end portion warp tension is 1.2 or less or the center portion warp tension/the end portion warp tension is <1.2, preferably 0.8 or less the center portion warp tension/the end portion warp tension is 1.2 or less, more preferably 0.8 or less the center portion warp tension/the end portion warp tension is 1.2 or less, and still more preferably 0.8 or less the center portion warp tension/the end portion warp tension is 1.1 or less). Further, by keeping the warp tension in the TD direction uniform, it is possible to suppress not only the slack at the end portions of the glass cloth but also the slack at the central portion.

The ratio of the tension of the warp yarns in the central portion of the glass cloth to the tension of the warp yarns in the end portions can be measured by measuring the tension of all the warp yarns and determining the difference between the average tension of the end portions and the average tension of the central portion. Specifically, the measurement can be carried out by the method described in examples.

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

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

[ winding characteristics ]

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

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

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

[ S-S Curve characteristic ]

In the center portion and the end portion of the glass cloth according to the present embodiment, the difference in the slope of the stress-strain curve (S-S curve) in the direction (MD) parallel to the warp is preferably 10% or less. The S-S curve of the MD of the glass cloth and the slope thereof 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 center portion of the glass cloth and the slope of the end portion 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 production step tends to decrease. From this viewpoint, the difference in the slope of the S-S curve in MD is more preferably 5% or less, still more preferably 3% or less, and still more preferably 1% or less. It is obvious that the lower limit of the difference in the slope of the S-S curve of MD exceeds 0%.

The difference in the slope of the S-S curve in the MD can be adjusted to be within a range of 10% or less by, for example, uniformly spreading the glass cloth along the TD in the spreading step to reduce the difference in the yarn width between the central portion and the end portion of the glass cloth. Specifically, in the fiber opening step, the ratio of the water pressure at the center of the glass cloth to the water pressure at the ends 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 components of the glass cloth according to the present embodiment will be described below.

[ kind of glass ]

As long as the amount of slack 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 viewpoint of low dielectric constant, relaxation amount, and suppression of occurrence of breakage, L glass, NL glass, L2 glass, or Q glass is preferably used.

[ composition of glass filaments ]

The glass filaments may have SiO₂May also have a composition other than SiO₂Other compositions, or alternatively, in SiO₂Has other compositions on the basis of (1). The other composition is not particularly limited, and examples thereof include Al₂O₃、CaO、MgO、B₂O₃、TiO₂、Na₂O、K₂O、Sr₂O₃、Fe₂O₃And the like. The composition amount can be adjusted according to the amount of raw materials used for making the glass filaments. From adjusting CTE toFrom a lower viewpoint, SiO₂The content is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, further preferably 95% by mass or more, and particularly preferably 99% by mass or more.

[ average filament diameter of glass filament ]

The average filament diameter of the glass filaments constituting the glass yarn is preferably 2 to 10 μm, more preferably 3.5 to 8 μm, and still more preferably 4 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 splitting step is less likely to occur, and fuzzing can be suppressed. Further, by adjusting the average filament diameter of the warp and weft 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 or processing pressure in the weaving step, the washing step, and the fiber opening step can be suppressed, and a thin glass cloth with suppressed fuzzing can be realized. In particular, the average filament diameter of the glass filaments is adjusted to be in the range of 4 μm to 6 μm, thereby suppressing thickness variation of the glass cloth.

[ number of glass filaments ]

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

[ declination amount of weft ]

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(Z₀、Z₁And Z₂) The maximum value among them.

Z_N＝|(Y_N+1-Y_N)/(X_N+1-X_N)|(I)

{ wherein N is 0 to 2, and X_N+1-X_NWhen the value of (A) is 0, Z_NIs 0. }

In the formula (I), X₀～X₃And Y₀～Y₃By (X)₀，Y₀)、(X₁，Y₁)、(X₂，Y₂) And (X)₃，Y₃) The combinations of (a) and (b) are defined as follows.

A glass cloth, a prepreg or a printed circuit board formed by a plurality of warps and a plurality of wefts is used as a sample to be tested, the warp direction of the sample to be tested is set as Y direction, the direction vertical to the Y direction is set as X direction, and the weft extending from the first warp to the second warp in the first warp and the second warp at both ends of the sample to be tested defines the point of origin (0, 0), namely (X) where the contact point of the first warp and the weft is used as the origin₀，Y₀) Y-axis and X-axis. In addition, the contact point of the second warp yarn and the weft yarn is set as a terminal point (X)₃，Y₃) Regarding the coordinates Y of the weft yarn on the X axis and the Y axis, one of points at which the maximum value and the minimum value appear is defined as (X)₁，Y₁) The other is set as (X)₂，Y₂) In this case, the weft yarns are arranged in sequence (X)₀，Y₀)、(X₁，Y₁)、(X₂，Y₂) And (X)₃，Y₃)。

Referring to FIGS. 2 to 4, Z is shown as an example₀、Z₁And Z₂The method of (3). Fig. 2 to 4 are schematic views showing one form of weft. 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, the origins (X) are arranged in the order of weft₀，Y₀) Point (X) representing the maximum value of Y₁，Y₁) Point (X) representing the minimum value of Y₂，Y₂) And end point (X)₃，Y₃)。Z₀By connecting two adjacent points (X)₀，Y₀) And (X)₁，Y₁) Calculated by substituting into the above formula (I), Z₁By connecting two adjacent points (X)₁，Y₁) And (X)₂，Y₂) Calculated by substituting into the above formula (I), Z₂By connecting two adjacent points (X)₂，Y₂) And (X)₃，Y₃) Substituted into the above formula (I).

In FIG. 3, the origins (X) are arranged in the order of weft₀，Y₀) Point (X) representing the maximum value of Y₁，Y₁) Point (X) representing the minimum value of Y₂，Y₂) And end point (X)₃，Y₃) Here, (X)₂，Y₂) And (X)₃，Y₃) Representing the same coordinates. Z₀、Z₁And Z₂The calculation can be performed in the same manner as described above with reference to fig. 2.

In addition, (X)₂，Y₂) And (X)₃，Y₃) Represent the same coordinate, therefore, Z₂In the above formula (I), a value of 0 is used.

In FIG. 4, the origins (X) are arranged in the order of weft₀，Y₀) Point (X) representing the maximum value of Y₁，Y₁) Point (X) representing the minimum value of Y₂，Y₂) And end point (X)₃，Y₃) Here, (X)₀，Y₀) And (X)₁，Y₁) Represent the same coordinate, and (X)₂，Y₂) And (X)₃，Y₃) Representing the same coordinate, Z₀、Z₁And Z₂The calculation can be performed in the same manner as described above with reference to fig. 2.

In addition, (X)₀，Y₀) And (X)₁，Y₁) Represent the same coordinate, therefore, Z₀In the above formula (I), Z is a value of 0₂A value of 0 is also used.

In the present description, the maximum value of the measured weft skew value is defined as the weft skew in the present embodiment. The skew amount was measured by the method described in examples according to JIS L1096.

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

For example, by increasing the opening tension in the opening step of producing the glass cloth, specifically, by opening such that the ratio of the opening tension to the tensile strength of the glass cloth exceeds 0.1 (i.e., opening tension/tensile strength >0.1), the skew amount of the weft yarn can be adjusted to be within 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 likely to occur in the surface treatment step and the prepreg production step in general, and the amount of relaxation is 10mm/m or less, whereby breakage can be significantly suppressed or prevented. From this viewpoint, the MD tensile strength is more preferably 100N/25mm or less, and still more preferably 50N/25mm or less.

The lower limit value of the MD tensile strength of the glass cloth is obviously more than 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 in a direction (TD) of 90 DEG to the warp of 0.03gf cm²Less than/cm. Bending stiffness is used as an index of texture by modeling the operation of bending a molded body such as glass cloth. In the art, the bending rigidity may reflect rigidity or the like in the texture of the glass cloth.

When the unit bending rigidity of the glass cloth is 0.03gf cm²In the range of/cm or less, breakage is generally likely to occur in the surface treatment step and the prepreg production step, and by setting the above relaxation amount to 10mm/m or less, breakage can be significantly suppressed or prevented. From this viewpoint, the unit bending rigidity is more preferably 0.02gf cm²Less than or equal to cm, more preferably 0.01gf cm²Less than/cm. The unit bending stiffness may be arbitrarily set according to the dimensional stability of the glass cloth, and may exceed 0gf cm, for example²In terms of a/cm. The unit bending stiffness (texture) of the glass cloth was measured by the method described in the examples.

[ beating-up density ]

The beating-up density of the warp and weft constituting the glass cloth is preferably 50 to 140 pieces/inch, more preferably 80 to 130 pieces/inch, independently.

[ cloth weight (weight per unit area) ]

The glass cloth preferably has a cloth weight (weight per unit area) of 4 to 200g/m²More preferably 10 to 100g/m²More preferably 10 to 60g/m²。

[ weaving structure ]

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

[ surface treatment ]

It is preferable that: the glass yarn (including glass filament) 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, reactivity with the matrix resin is further improved, and hydrophilic functional groups are less likely to be formed after the reaction with the matrix resin, whereby insulation reliability is further improved.

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, the moisture absorption resistance is further improved, and as a result, the insulation reliability tends to be further improved. In particular, SiO can be improved by using a silane coupling agent having an unsaturated double bond group₂Plating solution impregnation, insulation reliability and fuzz after drilling of glass cloth with a composition amount of 98-100 mass%And (4) quality.

X(R)_3-nSiY_n···(1)

(wherein X is an organic functional group having at least any one of 1 or more groups selected from 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 of at least any one selected from the group consisting of an amino group and an unsaturated double bond group, more preferably 3 or more, and still more preferably 4 or more of at least any one selected from the group consisting of an amino group and an unsaturated double bond group. When X is 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 a vinyl group, an allyl group, a vinylidene group, an acryloyloxy group, and a methacryloyloxy group.

Any form of alkoxy group can be used as the alkoxy group in the general formula (1), but an alkoxy group having 5 or less carbon atoms is preferable for stable treatment of the glass cloth.

Specific examples of the silane coupling agent include, but are not particularly limited to, N- β - (N-vinylbenzylaminoethyl) - γ -aminopropyltrimethoxysilane and hydrochloride thereof, N- β - (N-vinylbenzylaminoethyl) - γ -aminopropylmethyldimethoxysilane and hydrochloride thereof, N- β - (N-bis (vinylbenzyl) aminoethyl) - γ -aminopropyltrimethoxysilane and hydrochloride thereof, N- β - (N-bis (vinylbenzyl) aminoethyl) -N- γ - (N-vinylbenzyl) - γ -aminopropyltrimethoxysilane and hydrochloride thereof, aminopropyltrimethoxysilane, vinyltrimethoxysilane, gamma-aminopropyltrimethoxysilane, gamma-silyltrimethoxysilane, and the like, Known compounds such as methacryloxypropyltrimethoxysilane, methacryloxyoctyltrimethoxysilane and acryloxypropyltrimethoxysilane. The silane coupling agent tends to have excellent reactivity with a matrix resin of a glass yarn (glass filament) or a substrate of a glass cloth, particularly a radical polymerization resin. Therefore, there is a tendency that: the silane coupling agent can suppress a decrease in insulation reliability due to easy peeling of the resin and the glass cloth at the interface, and can also suppress a decrease in insulation reliability due to impregnation of the plating solution into the glass cloth.

[ counts ]

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 number of warp yarns and the number of 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, and more preferably 0.5g/1000m or more and 10.0g/1000m or less. The Tex of the glass cloth can be calculated by the following equation.

Tex＝m/l×1000

{ formula (ii), Tex: number of points

m: quality (g) of test piece

l: length (m) of test piece

[ method for producing glass cloth ]

The method for producing the glass cloth of the present embodiment is not particularly limited, and examples thereof include a method including the steps of: a covering step of almost completely covering the surface of the glass filaments with a silane coupling agent by using a treating fluid 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 filament by heating and drying.

Further, the method for manufacturing a glass cloth of the present embodiment may include: and an adjusting step of adjusting the amount of the silane coupling agent to be adhered by washing 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 the solvent for dissolving or dispersing the silane coupling agent, water or an organic solvent can be used, but water is preferably used as the main solvent from the viewpoint of safety and global environment protection. As a method for obtaining the treatment liquid using water as a main solvent, any of a method of directly charging the silane coupling agent into water, and a method of dissolving the silane coupling agent in a water-soluble organic solvent to prepare an organic solvent solution and then charging the organic solvent solution into water is preferable. In order to improve water dispersibility and stability of the silane coupling agent in the treatment liquid, a surfactant may be used in combination.

Preferably, the glass cloth is subjected to a covering step, a fixing step, and an adjusting step after the weaving step. Further, if necessary, a fiber opening step of opening the glass yarn of the glass cloth after the weaving step may be provided. When the adjusting step is performed after the weaving step, the adjusting step may also be used as the opening step. The composition of the glass cloth is usually unchanged before and after the fiber opening.

It can be considered that: by the above 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 may be used: (A) a method of storing the treatment liquid in a bath and immersing and passing the glass cloth (hereinafter referred to as "immersion method"); (B) a method of directly applying the treatment liquid to 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 (a), the dipping time of the glass cloth in the treatment solution is preferably selected to be 0.5 seconds to 1 minute.

Further, as a method of applying the treatment liquid to the glass cloth and then drying the solvent by heating, known methods such as hot air and electromagnetic waves can be cited.

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, and 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 lower, and more preferably 200 ℃ or lower.

The method of opening in the opening step is not particularly limited, and examples thereof include a method of opening a glass cloth with spray water (high-pressure water opening), a vibration washer, ultrasonic water, a mangle, and the like. In order to suppress the reduction in tensile strength of the glass cloth due to the spreading process, it is preferable to take measures such as reduction in friction of the contact member, optimization of the sizing agent, and increase in adhesion during weaving of the glass yarn. By reducing the tension applied to the glass cloth during the fiber opening process, the air permeability tends to be further reduced.

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

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

[ roll of glass cloth ]

In another embodiment of the present invention, a glass cloth roll can be formed, which includes a core tube made of acrylonitrile-butadiene-styrene (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 for 1000m with a width of 1.3m, the difference in winding hardness between the central portion and the end portion of the glass cloth is preferably 10 or less. When the difference in winding hardness between the central portion and the end portion of the glass cloth in a rolled state is 10 or less, it is possible to suppress the occurrence of breakage or reduce the frequency of breakage when the glass cloth is rolled in a 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 and has a low dielectric constant and improved 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 a compound having an epoxy group by reacting the compound having an epoxy group 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 are reactive 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, a phosphorus compound and the like; b) a radical polymerizable curing resin which cures a compound having at least one of an allyl group, a methacryloyl group, and an acryloyl group using a thermal decomposition catalyst or a photolysis catalyst as a reaction initiator; c) a maleimide triazine resin obtained by curing a compound having a cyanate group by reacting the compound having a maleimide group with a compound having a cyanate group; d) a thermosetting polyimide resin obtained by curing a maleimide compound by reacting with an amine compound; e) and benzoxazine resins in which a compound having a benzoxazine ring is crosslinked and cured by heating polymerization.

The thermoplastic resin is not particularly limited, and examples thereof include polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, aromatic polyamide, polyether ether ketone, 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 prepreg described above. Thus, a printed wiring board having a low dielectric constant and improved 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

Next, the present invention will be described in more detail by way of examples and comparative examples. The present invention is not limited to the following examples.

(example 1)

As shown in Table 1, a glass cloth was formed by weaving glass yarns made of L-glass, and the glass cloth was immersed in a treatment solution in which hydrochloride of N- β - (N-vinylbenzylaminoethyl) - γ -aminopropyltrimethoxysilane (manufactured by Toray Corning Co., Ltd.; Z6032) was dispersed in water, followed by heating and drying. Subsequently, high-pressure water was sprayed to open the fibers, followed by heating and drying to obtain a glass cloth product for evaluation.

(examples 2 to 12, comparative examples 1 to 6)

Glass cloth products for evaluation were obtained in the same manner as in example 1 except that the thickness of the glass cloth, the type of glass, the dielectric constant, the relaxation characteristics, the winding characteristics, and the like were changed as shown in table 1.

< method for evaluating thickness of glass cloth >

The measurement axis was statically rotated using a micrometer in accordance with 7.10 of JIS R3420, and the measurement surface was lightly contacted in parallel. And reading the scales after the ratchet wheel makes 3 times of sounds.

< method for producing substrate >

A 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 into the glass cloth obtained in the above examples/comparative examples, and the glass cloth was dried at 120 ℃ for 2 minutes to obtain a prepreg. The resin content of the prepreg was adjusted to 60 vol%. The prepregs were stacked, and copper foils having a thickness of 12 μm were further stacked up and down at 200 ℃ and 40kg/cm²The substrate was obtained by heating and pressurizing for 60 minutes.

< method for measuring/calculating dielectric constant >

In the above manner, a substrate was prepared so that the resin content of the prepreg in an average 100 vol% became 60 vol%, and the copper foil was removed to obtain a sample for evaluation of dielectric constant. The dielectric constant of the obtained sample was measured at a frequency of 10GHz using an impedance analyzer (Agilent Technologies). From the obtained substrate dielectric constant, the relative dielectric constant (Dk) of the glass cloth at 10GHz was calculated from the volume fraction of the glass cloth and the resin dielectric constant 2.5.

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

In the weaving step, the tension per 1 warp yarn at the time of smoothing out the warp yarns was measured to 0.1cN unit using a low-load digital tensiometer (ZEF-100) manufactured by SCHMIDT. The average warp tensions at the portions (end portions) from both ends to 20% and at the portions (central portion) other than the end portions were calculated, respectively, and the central portion warp tension/the end portion warp tension were obtained.

< measurement of relaxation amount >

As shown in fig. 1, a glass cloth (1) having a width total length t of 1000mm is horizontally laid on two rolls (4, 4) having an inter-roll distance of 1m, both MD ends (end portions 2 in fig. 1 b) of the glass cloth (1) are held, and when the glass cloth (1) is stretched with a force of a tension of 50N in the MD direction, the most recessed portion of the cloth is visually judged, and a recessed amount in the vertical direction (z direction) of a glass cloth slack portion (3) is measured up to 1mm unit using a laser displacement meter (LK-G5000) manufactured by kynski corporation as a slack amount (x). The amount of the dent is a distance from a plane where the upper surfaces of the two rolls (4, 4) are connected by a straight line to a portion where the glass cloth (1) is farthest away.

< winding test >

A glass cloth was wound around an ABS core tube (hardness: 90) having a core tube diameter of 200mm to a length of 1000m at a width of 1.3m to produce a wound body.

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

Further, the difference in the slope of the stress-strain curve in the direction (MD) parallel to the warp of the glass cloth was measured at the center and the end of the roll by Autograph "AGS-J5 kN" manufactured by shimadzu corporation.

< weft skew amount >

The weft 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 rollers was visually observed, the displacement from the reference line was measured with the TD tangent line of the roller and the cloth as the reference line, the difference between the maximum value and the minimum value of the displacement was calculated as the skew amount, and this 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 flexural rigidity (texture) >

The unit bending stiffness (gf cm) of the glass cloth was measured using "KES-FB 2-A" manufactured by KATOTECH as a bending tester²/cm)。

< frequency of breakage in surface treatment of glass cloth >

In the examples and comparative examples, as described above, the glass cloth was immersed in the silane coupling agent treatment solution in which hydrochloride of N-. beta. - (N-vinylbenzylaminoethyl) - γ -aminopropyltrimethoxysilane (manufactured by Toliento Corning Co., Ltd.; Z6032) was dispersed in water, and whether or not the glass cloth was broken when a force was applied in the Z direction of the glass cloth to scrape off the excess silane coupling agent by passing through two pairs of rollers was observed, and the breakage frequency (%) of the glass cloth with respect to the number N was calculated.

< frequency of breakage in prepreg production Process >

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

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

[ tables 1-1]

[ tables 1-2]

From the comparison of examples 8 to 9 with comparative examples 5 to 6: in comparative examples, the thinner the glass cloth, the more likely the glass cloth is broken, but in examples 8 to 9, even under the condition that the glass cloth is easily broken, the effect of the present invention is remarkably exhibited by controlling the amount of slack.

Description of the reference numerals

1 glass cloth

2 ends of glass cloth

3 glass cloth slack portion

4 rollers

Amount of x relaxation

t full width

Claims

1. A glass cloth comprising glass yarns formed of a plurality of glass filaments as warp yarns and weft yarns, wherein the width in The Direction (TD) at 90 DEG to the warp yarns 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 slack in the vertical direction when the tension in the direction (MD) parallel to the warp yarns is 50N is 10mm/m or less.

2. The glass cloth according to claim 1, wherein a 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 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 1000m of the glass cloth having a width of 1.3 m.

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

5. Glass cloth according to any one of claims 1 to 4, wherein the weft skew amount of the weft yarns is 10mm or less.

6. Glass cloth according to any of claims 1 to 5, wherein the thickness of the glass cloth is 25 μm or less.

7. Glass cloth according to any of claims 1 to 6, wherein the thickness of the glass cloth is 17 μm or less.

8. Glass cloth according to any one of claims 1 to 7, wherein the tensile strength in the direction (MD) parallel to the warp yarns is 150N/25mm or less.

9. Glass cloth according to any one of claims 1 to 8, wherein the unit bending stiffness in The Direction (TD) at 90 ° to the warp is 0.03 gf-cm²Less than/cm.

10. Glass cloth according to any of claims 1 to 9, wherein the glass cloth has a width in The Direction (TD) at 90 ° to the warp yarns of 2000mm or less.

11. Glass cloth according to any of claims 1 to 10, wherein the amount of relaxation is 6mm/m or less.

12. The glass cloth according to claim 11, wherein the amount of slack is 4mm/m or less.

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

14. A prepreg, comprising:

a glass cloth as defined in any one of claims 1 to 13; and

a matrix resin impregnated in the glass cloth.

15. A printed circuit board comprising the prepreg of claim 14.

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

when the glass cloth is wound on a core tube made of acrylonitrile-butadiene-styrene copolymer (ABS) with a core tube diameter of 200mm for 1000m in a width of 1.3m, the difference in winding hardness between the central part and the end part of the glass cloth is 10 or less.