TWI854270B - Glass cloth, prepreg, printed circuit boards and electronic equipment - Google Patents

Abstract

The object of the present invention is to provide a glass cloth, a prepreg using the glass cloth, and a printed circuit board, wherein the glass cloth has higher productivity by being rolled up without generating wrinkles even when conveying low-quality glass cloth at high speed.

The present invention provides a glass cloth woven with glass yarns including a plurality of glass filaments as warp yarns and weft yarns, wherein the mass of the glass cloth is less than 11.5 g/ ^m2 , and (i) the bending rigidity Bw of the warp yarns of the glass cloth is in the range of 0.0030-0.0080 gf. ^cm2 /cm, and the bending rigidity Bf of the weft yarns of the glass cloth is in the range of 0.0020-0.0050 gf. ^cm2 /cm; or (ii) the average number of segments of the glass cloth is in the range of 3.0-5.0, the opening degree of the warp yarns of the glass cloth is 0.55-0.90, and the opening degree of the weft yarns is 0.65-0.97.

Description

Glass cloth, prepreg, printed circuit boards and electronic machines

The present invention relates to a glass cloth, a prepreg, and a printed circuit board.

In recent years, with the miniaturization of electronic devices, there is a growing need to make printed circuit boards lighter. In order to reduce the quality of the materials used in printed circuit boards, the quality of the glass cloth contained in the prepreg is also required to be reduced.

A method for suppressing pinholes in prepregs using low-quality glass cloth is reported (Patent Documents 1-4). Patent Documents 1-4 suppress pinholes generated in prepregs by controlling the fiber opening degree of glass cloth or the gap spacing of yarn width. In addition, in Patent Document 5, a method for reducing the warp of printed circuit boards using low-quality glass cloth is reported. In addition, in Patent Document 6, a method is disclosed, which controls the surface glass yarn coverage, so that printed circuit boards using low-quality glass cloth also show excellent dimensional stability and mechanical properties.

[Prior Art Literature] [Patent Literature]

[Patent document 1] Japanese Patent No. 6818278

[Patent Document 2] Japanese Patent Publication No. 5905150

[Patent Document 3] Japanese Patent Publication No. 6020764

[Patent Document 4] Japanese Patent Publication No. 6536764

[Patent Document 5] Japanese Patent No. 6421755

[Patent Document 6] Japanese Patent No. 4446754

Since low-quality glass cloth and prepreg are thin, wrinkles are likely to occur during roll-to-roll conveying in most cases. However, although Patent Document 1 also reports a method for suppressing pinholes in prepregs while suppressing wrinkles extending in the mechanical direction (longitudinal wrinkles) during manufacturing, there is still room for improvement in suppressing wrinkles during glass cloth conveying. Therefore, the purpose of the present invention is to provide a glass cloth, a prepreg using the glass cloth, and a printed circuit board, wherein the glass cloth has higher productivity by being rolled up without wrinkles even when low-quality glass cloth is conveyed at high speed.

The inventors of the present invention have conducted research to solve the above problem and found that the lower the quality of the glass cloth, the thinner the thickness, so it is easy to produce wrinkles when transported in a roll-to-roll manner. It is believed that this is as shown in the following formula. The bending rigidity depends to a large extent on the thickness. The thinner the thickness, the easier it is to cause wrinkles (buckling phenomenon) due to the lower rigidity.

Flexural rigidity = Et _w ³ W/12

{Wherein, E: Young's modulus of the web

_tw : thickness of web

W: Width of the belly plate}

Therefore, the inventors of the present invention have found the following: by controlling the bending rigidity of thinner glass cloth that is prone to wrinkles, pinholes can be suppressed when the glass cloth is made into a prepreg, and it can be rolled up without wrinkles during transportation; and by reducing the fiber opening degree of the glass cloth to a level that does not generate pinholes when making a prepreg, the thickness of the glass cloth of the same quality can be increased, and it can be rolled up without wrinkles during transportation; thus completing the present invention. The following is an example of a part of the present invention.

[1]

A glass cloth is woven by weaving glass yarns including a plurality of glass filaments as warp yarns and weft yarns, wherein the mass of the glass cloth is less than 11.5 g/ ^m2 , the bending rigidity Bw of the warp yarns of the glass cloth is in the range of 0.0030 to 0.0080 gf. ^cm2 /cm, and the bending rigidity Bf of the weft yarns of the glass cloth is in the range of 0.0020 to 0.0050 gf. ^cm2 /cm.

[2]

The glass cloth as described in item 1, wherein the bending stiffness ratio Bw/Bf of the warp yarn and weft yarn of the above-mentioned glass cloth is less than 1.9.

[3]

A glass cloth is woven by weaving glass yarns including a plurality of glass filaments as warp yarns and weft yarns, wherein the mass of the glass cloth is less than 11.5 g/ ^m2 , the average number of segments of the glass cloth is in the range of 3.0 to 5.0, the warp yarns of the glass cloth have an opening degree of 0.55 to 0.90, and the weft yarns have an opening degree of 0.65 to 0.97.

[4]

The glass cloth as described in item 3, wherein the average fiber opening degree represented by the average value of the fiber opening degree of the above-mentioned warp yarn and the fiber opening degree of the above-mentioned weft yarn is in the range of 0.60 to 0.93.

[5]

The glass cloth as described in any one of items 1 to 4 comprises warp yarns and weft yarns formed by bundling glass filaments having a diameter in the range of 2.5 μm to 4.0 μm in a range of 10 to 50 pieces, and the weaving density of the warp yarns is in the range of 85 to 150 pieces/inch, and the weaving density of the weft yarns is in the range of 85 to 150 pieces/inch.

[6]

Glass cloth as described in any one of items 1 to 5, wherein the thickness of the glass cloth is in the range of 8μm~18μm.

[7]

Glass cloth as described in any one of items 1 to 6, which is surface treated with a silane coupling agent.

[8]

The glass cloth as described in item 7, wherein the silane coupling agent comprises a silane coupling agent represented by the following general formula (1): X(R) _3-n SiY _n …(1)

(In the formula, X is an organic functional group containing one or more amino groups, an organic functional group containing one or more unsaturated double bond groups with free radical reactivity, or an organic functional group containing one or more amino groups and one or more unsaturated double bond groups with free radical reactivity, Y is independently an alkoxy group, n is an integer from 1 to 3, and R is independently a group selected from the group consisting of methyl, ethyl and phenyl groups).

[9]

A prepreg characterized by comprising a glass cloth as described in any one of items 1 to 8, a thermosetting resin, and an inorganic filler.

[10]

A printed circuit board, characterized in that it comprises a prepreg as described in item 9.

[11]

An integrated circuit, characterized in that it comprises a printed circuit board as described in item 10.

[12]

An electronic machine, characterized in that it comprises a printed circuit board as described in item 10.

According to the present invention, it is possible to provide a low-quality glass cloth that suppresses the generation of wrinkles during transportation and exhibits higher productivity, as well as a prepreg using the glass cloth and a printed circuit board.

The following describes the implementation method of the present invention (hereinafter referred to as "this implementation method") in detail, but the present invention is not limited thereto and various changes can be made within the scope of the gist thereof.

[Glass cloth]

The glass cloth of this embodiment is formed by weaving glass yarns including a plurality of glass filaments as warp yarns and weft yarns. The glass cloth is preferably surface treated with a surface treatment agent described below.

[Glass Type]

The glass cloth used in the laminate is usually called E glass (alkali-free glass), but in the glass cloth of the present embodiment, for example, L glass, NE glass, D glass, L2 glass glass, S glass, T glass, silica glass, quartz glass, etc. can also be used. From the perspective of dielectric properties, L glass, L2 glass, silica glass, quartz glass, etc. are more preferably used, and silica glass and quartz glass are particularly preferred. In addition, from the perspective of improving the dimensional stability of the laminate including the glass cloth, S glass, T glass, silica glass, and quartz glass are more preferably used, and silica glass and quartz glass are particularly preferred.

[Physical properties and structure of glass cloth]

The mass of the glass cloth of the present embodiment is 11.5 g/m ² or less in terms of mass per unit area according to JIS R3420. From the viewpoint of reducing the thickness of the prepreg or printed wiring board including the glass cloth, it is preferably 11.3 g/m ² or less, more preferably 11.0 g/m ² or less, further preferably 10.5 g/m ² or less, and particularly preferably 10.0 g/m ² or less. The lower limit of the mass per unit area of the glass cloth is not particularly limited, and may be, for example, more than 0 g/m ² , 0.1 g/m ² or more, etc.

If the mass of the glass cloth is to be less than 11.5 g/m ² , the glass yarns used for the warp and weft yarns of the glass cloth are preferably thinner. The diameter of the glass filaments of the present embodiment is preferably in the range of 2.5 μm to 4.0 μm, more preferably 2.8 μm to 3.9 μm, further preferably 3.0 μm to 3.8 μm, and particularly preferably 3.1 μm to 3.7 μm. If the filament diameter is less than 2.5 μm, the breaking strength of the filament becomes low, and thus hairiness is easily generated. Moreover, if the filament diameter exceeds 4.0 μm, it is difficult to make the mass of the glass cloth less than 11.5 g/m ² .

The average number of segments of the glass cloth of this embodiment is in the range of 3.0 to 5.0, preferably in the range of 3.2 to 4.7, more preferably in the range of 3.4 to 4.4, further preferably in the range of 3.5 to 4.1, and particularly preferably in the range of 3.6 to 4.0. When the average number of segments is less than 3.0, the thickness of the glass cloth becomes thinner, so wrinkles are easily generated when the glass cloth is transported. On the other hand, if the average number of segments exceeds 5.0, the pinhole generation rate of the prepreg becomes higher. By making the average number of segments of the glass cloth within the above range, wrinkles during the transportation of the glass cloth can be suppressed while taking into account the suppression of pinholes in the prepreg.

The fiber opening degree of the warp yarn of the glass cloth of this embodiment is in the range of 0.55-0.90, and the fiber opening degree of the weft yarn is in the range of 0.65-0.97; preferably, the fiber opening degree of the warp yarn is in the range of 0.60-0.89, and the fiber opening degree of the weft yarn is in the range of 0.70-0.96; more preferably, the fiber opening degree of the warp yarn is in the range of 0.65-0.88. The opening degree of the weft yarn is preferably within the range of 0.75 to 0.95; more preferably, the opening degree of the warp yarn is within the range of 0.67 to 0.87, and the opening degree of the weft yarn is within the range of 0.77 to 0.94; and most preferably, the opening degree of the warp yarn is within the range of 0.68 to 0.86, and the opening degree of the weft yarn is within the range of 0.78 to 0.93. By making the opening degree of the warp yarn and the weft yarn of the glass cloth within the above range, wrinkles of the glass cloth during transportation can be suppressed while taking into account the suppression of pinholes in the prepreg. If the opening degree exceeds the upper limit of the above numerical range, the opening degree is high, so wrinkles are easily generated when conveying the glass cloth. On the other hand, if the opening degree is lower than the lower limit of the above numerical range, the pinhole generation rate when making the prepreg becomes high.

In addition, the average fiber opening of the glass cloth of the present embodiment is preferably in the range of 0.60 to 0.93, more preferably in the range of 0.62 to 0.93, further preferably in the range of 0.64 to 0.92, further preferably in the range of 0.66 to 0.92, and particularly preferably in the range of 0.67 to 0.91. By making the average fiber opening of the glass cloth within the above range, wrinkles of the glass cloth during transportation can be suppressed while taking into account the suppression of pinholes in the prepreg. Furthermore, the average fiber opening of the glass cloth is expressed as the average value of the fiber opening of the warp yarn and the fiber opening of the weft yarn.

In addition, the number of filaments of the glass yarn used in the warp and weft yarns of the glass cloth of the present embodiment is preferably in the range of 10 to 50, more preferably in the range of 15 to 45, further preferably in the range of 20 to 43, and particularly preferably in the range of 25 to 40. If the number of filaments exceeds 50, it is easy to cause insufficient expansion rate during flattening processing such as fiber opening processing of the glass cloth. In addition, if the number of filaments is less than 10, the glass cloth is prone to hairiness. Glass filaments within the above number range can be bundled when forming glass yarn.

From the perspective of the range in which the effect of the present invention is significantly manifested, it is preferred that the weaving density of the warp yarn of the glass cloth of the present embodiment is in the range of 85 to 150 yarns/inch, the weaving density of the weft yarn is in the range of 85 to 150 yarns/inch, and the weaving density of the warp yarn and the weft yarn is more preferably in the range of 88 to 140 yarns/inch, further preferably 90 to 135 yarns/inch, and particularly preferably 95 to 130 yarns/inch.

The thickness of the glass cloth of this embodiment is preferably in the range of 8μm~18μm, more preferably 9μm~17μm, further preferably 9μm~16μm, further preferably 9μm~15μm, and particularly preferably 10μm~15μm. If the thickness of the glass cloth is less than 8μm, the plasticity of the glass cloth disappears, so wrinkles are easily generated during transportation. In addition, if the thickness of the glass cloth exceeds 18μm, the expansion rate of the glass cloth is insufficient, and pinholes are easily generated in the prepreg.

[Surface treatment agent (silane coupling agent)]

The glass yarn (including glass filaments) constituting the glass cloth is preferably surface treated with a surface treatment agent such as a silane coupling agent. As the silane coupling agent, it is preferred to use a silane coupling agent represented by the following general formula (1): X(R) _3-n SiY _n …(1)

{In formula (1), X is an organic functional group containing one or more amino groups, an organic functional group containing one or more unsaturated double bond groups with free radical reactivity, or an organic functional group containing one or more amino groups and one or more unsaturated double bond groups with free radical reactivity, Y is independently an alkoxy group, n is an integer from 1 to 3, and R is independently a group selected from the group consisting of methyl, ethyl and phenyl}.

X in the general formula (1) may be, for example, an organic functional group containing at least one free radical-reactive carbon-carbon double bond or other unsaturated double bond with free radical reactivity, an organic functional group containing at least one amine group, or an organic functional group containing at least one free radical-reactive unsaturated double bond and at least one amine group. The amine group may be, for example, a primary amine group, a secondary amine group, a tertiary amine group, or a quaternary ammonium salt. As for Y in the general formula (1), any form of alkoxy group may be used, but in order to stabilize the glass cloth, an alkoxy group with a carbon number of 5 or less is preferred.

As the surface treatment agent, the silane coupling agent represented by the general formula (1) may be used alone, or two or more silane coupling agents having different Xs in the general formula (1) may be used in combination. Examples of the silane coupling agent represented by the general formula (1) include N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane and its hydrochloride. Silane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyl trimethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-amino propyl triethoxysilane and its hydrochloride, γ-(2-aminoethyl)aminopropyl trimethoxysilane, γ-(2-aminoethyl)aminopropyl triethoxysilane, aminopropyl trimethoxysilane, vinyl trimethoxysilane, methacryloyloxypropyl trimethoxysilane, acryloxypropyl trimethoxysilane and other known single components, or mixtures thereof.

The surface treatment method of the glass cloth of the present embodiment is not particularly limited. For example, a method having the following steps can be cited: a coating step, which is to use a treatment liquid containing a silane coupling agent to cover the surface of the glass filament with the silane coupling agent; and a fixing step, which is to fix the silane coupling agent on the surface of the glass filament by heating and drying. The treatment liquid preferably contains 0.1 wt% to 3.0 wt% of the silane coupling agent. Preferably, the surface of the glass filament is almost completely covered with the silane coupling agent by the coating step.

As a method for applying the treatment liquid to the glass cloth, the following methods can be used: (A) a method of storing the treatment liquid in a bath and allowing the glass cloth to be immersed and passed (hereinafter referred to as the "immersion method"); (B) a method of directly applying the treatment liquid to the glass cloth using a roll coater, a die-mouth coater, or a gravure coater. When applying by the immersion method (A) above, it is preferred to select the immersion time of the glass cloth in the treatment liquid to be more than 0.5 seconds and less than 1 minute.

The heating and drying temperature is preferably above 90°C, and more preferably above 100°C, so that the reaction between the silane coupling agent and the glass can proceed fully. In addition, in order to prevent the degradation of the organic functional groups contained in the silane coupling agent, the heating and drying temperature is preferably below 300°C, and more preferably below 200°C.

The surface treatment method of the glass cloth of this embodiment may also include an adjustment step, wherein the adjustment step is to adjust the amount of silane coupling agent attached to the surface of the glass filament by washing at least a portion of the silane coupling agent fixed to the surface of the glass filament with a cleaning liquid such as water. The cleaning can be performed by high-pressure water spraying, etc.

As a solvent for dissolving or dispersing the silane coupling agent, either water or an organic solvent can be used. From the perspective of safety and environmental protection, water is preferably used as the main solvent. As a method for obtaining a treatment solution with water as the main solvent, any of the following methods is preferred: a method of directly adding the silane coupling agent to water; or a method of adding the organic solvent solution to water after dissolving the silane coupling agent in a water-soluble organic solvent. In order to improve the water dispersibility or stability of the silane coupling agent in the treatment solution, a surfactant can also be used.

The above-mentioned coating step, fixing step and adjustment step are preferably performed on the glass cloth after the weaving step. Furthermore, the fiber opening step of the glass yarn of the glass cloth can also be performed after the weaving step as needed. Furthermore, when the adjustment step is performed after the weaving step, the adjustment step can also serve as the fiber opening step. Furthermore, the composition of the glass cloth usually does not change before and after the fiber opening. It is believed that the above-mentioned manufacturing method can form a silane coupling agent layer almost completely and uniformly on the entire surface of each glass filament constituting the glass yarn.

[Fiber opening steps]

There is no particular limitation on the fiber opening method of glass cloth. For example, there are methods of fiber opening glass cloth using water jet (high-pressure water fiber opening), vibration cleaning device, ultrasonic water, roller press, etc. During the fiber opening process, the yarn width of the glass cloth can be reduced by increasing the tension applied to the glass cloth, and the yarn width of the glass cloth tends to be expanded by reducing the tension. Furthermore, in order to suppress the decrease in the tensile strength of the glass cloth caused by the fiber opening process, it is better to implement measures such as low friction of the contact member when weaving the glass cloth, or optimization and high adhesion quantification of the bundling agent.

The water pressure of the high-pressure water fiber opening of the glass cloth in this embodiment is preferably 0.13MPa or less, more preferably 0.12MPa or less, further preferably 0.11MPa or less, and further preferably 0.10MPa or less. If the water pressure of the high-pressure water fiber opening exceeds 0.13MPa, the yarn width of the glass cloth will increase, and wrinkles during high-speed transportation cannot be suppressed.

In addition, during the fiber opening process, by increasing the tension applied to the glass cloth, the yarn width of the glass cloth can be reduced. On the other hand, by reducing the tension, the yarn width of the glass cloth tends to expand. For a glass cloth with a width of 1300 mm, the tension applied to the glass cloth in the longitudinal direction of the present embodiment is preferably 50 N or more, more preferably 60 N or more, further preferably 70 N or more, further preferably 80 N or more. There is no particular upper limit on the tension applied to the glass cloth in the longitudinal direction, as long as it is within the range where the glass cloth will not break or wrinkle. If the tension in the longitudinal direction is less than 50 N, the yarn width of the glass cloth is easily expanded, and wrinkles during high-speed conveyance cannot be suppressed.

[Flexural rigidity]

In this embodiment, it is found that the lower the quality of the glass cloth, the thinner the thickness, so wrinkles are easily generated when it is transported in a roll-to-roll manner. The reason is believed to be that, as described in the following formula, the bending rigidity depends largely on the thickness, and the thinner the thickness, the lower the rigidity, which makes wrinkles (buckling phenomenon) more likely to occur.

Flexural rigidity = Et _w ³ W/12

{Wherein, E: Young's modulus of the web

_tw : thickness of web

W: Width of the belly plate}

As mentioned above, the bending rigidity of glass cloth depends largely on the thickness of the glass cloth, so the bending rigidity can be controlled by adjusting the yarn width of the warp and weft yarns of the glass cloth. In order to suppress the wrinkles of the glass cloth during transportation, it is better to improve the bending rigidity of the glass cloth, so the yarn width of the warp and weft yarns tends to be as narrow as possible.

The bending rigidity Bw of the warp yarn of the glass cloth of the present embodiment is in the range of 0.0030-0.0080 gf. cm ² /cm, and the bending rigidity Bf of the weft yarn of the glass cloth is in the range of 0.0020-0.0050 gf. cm ² /cm. With respect to each of Bw and Bf, Bw is preferably in the range of 0.0032-0.0078 gf. cm ² /cm, and Bf is preferably in the range of 0.0022-0.0048 gf. cm ² /cm; Bw is more preferably in the range of 0.0034-0.0076 gf. cm ^{2 /cm, and Bf is more preferably in the range of 0.0024-0.0046 gf. cm 2} /cm. Bw is preferably in the range of 0.0035 to ^0.0074 gf. cm ² /cm; Bf is more preferably in the range of 0.0025 to 0.0044 gf. cm ² /cm; Bw is more preferably in the range of 0.0036 to 0.0070 gf. cm ² /cm, and Bf is more preferably in the range of 0.0026 to 0.0040 gf. cm ² /cm. If the bending rigidity is lower than the above lower limit, wrinkles are easily generated when the glass cloth is transported. On the other hand, if the bending rigidity exceeds the above upper limit, pinholes are easily generated when the prepreg is produced. Therefore, by controlling the bending rigidity of the thin glass cloth that is prone to wrinkling within the numerical range described above, the generation of pinholes when the glass cloth is made into a prepreg can be suppressed, and the glass cloth can be rolled up without wrinkling during transportation.

Furthermore, if the ratio of the bending rigidity Bw of the warp yarn to the bending rigidity Bf of the weft yarn exceeds 1.9, the difference in plasticity between the warp yarn and the weft yarn is too large, so wrinkles are easily generated when conveying the glass cloth. Therefore, the bending rigidity ratio Bw/Bf of the warp yarn and the weft yarn of the glass cloth of this embodiment is preferably 1.9 or less, more preferably 1.85 or less, further preferably 1.80 or less, further preferably 1.75 or less, and particularly preferably 1.70 or less.

[Prepreg]

In order to manufacture the prepreg as one form of the present invention, it is sufficient to follow the conventional practice. For example, after the glass cloth described above is impregnated with a thermosetting resin varnish (hereinafter also referred to as "varnish") obtained by diluting a base resin such as epoxy resin with an organic solvent, the organic solvent is volatilized in a drying furnace, and the thermosetting resin is cured to the B stage (semi-cured state) to manufacture the prepreg. Furthermore, the amount of base resin attached to the glass cloth is preferably such that the mass of the solid content of the varnish is 20% to 80% by mass relative to the total mass of the solid content of the varnish and the glass cloth.

Examples of the matrix resin used in the prepreg of the present invention include thermosetting resins such as epoxy resins, unsaturated polyester resins, polyimide resins, dimaleimide triazine (BT) resins, and cyanate resins, or thermoplastic resins such as polyphenylene ether (PPO) resins, polyetherimide resins, and fluororesins, or mixed resins thereof. In addition, a resin in which inorganic fillers such as aluminum hydroxide, talc, and silica fillers are mixed can also be used.

Furthermore, a printed circuit board including a prepreg structured as described above is also one form of the present invention, and an integrated circuit and electronic device including the printed circuit board can be provided.

[Implementation example]

The present invention is described in detail below using embodiments and comparative examples. However, the present invention is not limited to the embodiments.

[Physical properties of glass cloth]

The physical properties of glass cloth, specifically, the thickness of glass cloth, the mass of warp yarn and weft yarn, the diameter of the filaments constituting the warp yarn and weft yarn, and the weaving density of the warp yarn and weft yarn are measured in accordance with JIS R3420.

[Number of filaments in warp and weft yarns]

Observe the cross section of the yarn, count the number of filaments, and take the average of 5 measured values.

[Warp and weft width of glass cloth]

From the glass cloth obtained in the embodiment and comparative example, five pieces of glass cloth with a size of 70 mm in the warp direction and 70 mm in the weft direction were cut and used as test pieces for yarn bundle measurement.

Use a macroscope to observe the yarn bundle measurement test piece from the vertical direction at a magnification of 100 times. For each test piece, randomly measure the yarn width of 250 warp yarns, and find the average value of the yarn width of the 250 warp yarns obtained, and use the average value as the warp yarn width.

Similarly, for each test piece, randomly measure the yarn width of 250 weft yarns, find the average value of the yarn width of the 250 weft yarns obtained, and use the average value as the weft yarn width.

[Fiber opening degree of glass cloth]

The opening degree of the warp and weft yarns of the glass cloth is calculated using the following formula.

Warp yarn opening degree = warp yarn width [μm] ÷ (number of filaments in the warp yarn × diameter of the filaments in the warp yarn [μm])

Weft yarn opening degree = weft yarn width [μm] ÷ (number of weft yarn filaments × weft yarn filament diameter [μm])

In addition, the average fiber opening degree of the glass cloth is set as the average value of the fiber opening degrees of the warp yarn and the weft yarn.

[Average number of glass cloth segments]

The average number of sections of glass cloth is calculated using the following formula.

Average number of segments = glass cloth thickness [μm] ÷ (average value of warp and weft yarn filament diameter [μm])

[Bending rigidity of glass cloth]

The bending rigidity of glass cloth was measured 5 times under the following measurement conditions using a pure bending tester (KES-FB2-A, Kado Technology Co., Ltd.). The bending rigidity of warp yarn and weft yarn was obtained by using the average value of 5 measured values. In addition, the bending rigidity was measured based on the value of the first bending test and the sample was changed each time, and a total of 5 measurements were performed.

<Measurement conditions>

Sample width: 10 (cm)

SENS: 4(gf)

Maximum curvature: ±2.5 (1/cm)

Bending speed: 0.500 ([1/cm]/sec)

Curvature range for calculating bending stiffness: +0.5~+1.5

[Boron content in glass cloth]

The boron content in the glass cloth is determined by ICP (Inductively Coupled Plasma) emission spectrometry. PS3520VDDII manufactured by Hitachi High-Tech Science was used for ICP emission spectrometry. Specifically, regarding the boron content, the glass cloth sample was weighed, dissolved with sodium carbonate, dissolved in dilute nitric acid and fixed to volume, and then the boron content in the sample was determined by ICP emission spectrometry.

[Evaluation of wrinkles generated when transporting glass cloth]

之樹脂製芯管。評估此時產生褶皺之情況。 At a conveying speed of 60m/min, under the following conditions, roll the glass cloth with a product width of 1300mm and a cloth length of 2000m onto a roll with an outer diameter of 300mm.

Evaluate the wrinkles that occur at this time.

<Scrolling conditions>

Transport speed = 60m/min

Winding tension = 300N

Tension cone = 40%

Winding contact pressure = 30MPa

Contact pressure cone = 0%

<Wrinkle Assessment>

A: No wrinkles are generated during the rolling process

B: Less than 2 wrinkles are generated during the rolling process

C: Wrinkles are generated more than 3 times during the rolling process, or wrinkles are always generated during the rolling process

[Prepreg production method]

80 parts by weight of low-brominated bisphenol A type epoxy resin, 20 parts by weight of cresol novolac type epoxy resin, 2 parts by weight of dicyandiamide, 0.2 parts by weight of 2-ethyl-4-methylimidazole, and 100 parts by weight of 2-methoxy-ethanol were prepared. The prepreg coating was carried out under the following conditions: the glass cloth was conveyed at a speed of 3m/min, and the glass cloth was immersed in the epoxy resin varnish, and the excess varnish was scraped off through the narrow slit with the resin content adjusted to 68% by weight, and then dried at a drying temperature of 170°C and a drying time of 1 minute and 30 seconds.

[Pinhole evaluation of prepreg]

Samples of 400mm×400mm size were taken from the obtained prepreg. After sampling 150 pieces of the above-mentioned size, the number of pinholes was counted by visual inspection. The prepreg with 4 or less pinholes in each piece was counted as a good product, and the good product rate among the 150 pieces was evaluated.

(Implementation Example 1)

Use silica glass yarn with an average filament diameter of 3.6 μm, a number of filaments of 38, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 3.6 μm, a number of filaments of 38, and a twist number of 1.0. Z silicon dioxide glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide embryonic glass cloth with a weaving density of 105 warp yarns/inch and 110 weft yarns/inch. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, ultrasonic waves with a frequency of 25 kHz and a power of 0.30 W/ ^cm2 were used to irradiate the water. The fiber was opened (the tension in the warp direction during the fiber opening process was 90N). The obtained glass cloth after fiber opening had a warp width of 104μm and a weft width of 112μm.

(Example 2)

The grey cloth glass cloth obtained in Example 1 was used and processed in the same manner as Example 1 except that high-pressure water fiber opening (water pressure: 0.09Mpa, tension in the warp direction during fiber opening: 105N) was used instead of ultrasonic fiber opening. The obtained fiber opening glass cloth had a warp yarn width of 120μm and a weft yarn width of 130μm.

(Implementation Example 3)

The grey cloth glass cloth obtained in Example 1 was used and processed in the same way as Example 1 except that high-pressure water fiber opening (water pressure: 0.05Mpa, tension in the warp direction during fiber opening: 115N) was used instead of ultrasonic fiber opening. The obtained glass cloth after fiber opening had a warp yarn width of 94μm and a weft yarn width of 108μm.

(Implementation Example 4)

Use silica glass yarn with an average filament diameter of 3.5 μm, a number of filaments of 40, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 3.5 μm, a number of filaments of 40, and a twist number of 1.0. Z silicon dioxide glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide embryonic glass cloth with a weaving density of 110 warp yarns/inch and 110 weft yarns/inch. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, the fibers were opened by high-pressure water (water pressure: 0.05 MPa, the warp yarn during the opening process The tension in the direction: 100N) is applied to perform fiber opening. The warp yarn width of the glass cloth obtained after fiber opening is 100μm, and the weft yarn width is 112μm.

(Example 5)

Use silica glass yarn with an average filament diameter of 4.0 μm, a number of filaments of 40, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 4.0 μm, a number of filaments of 40, and a twist number of 1.0. Z silicon dioxide glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide embryonic glass cloth with a weaving density of 96 warp yarns/inch and 96 weft yarns/inch. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, the fibers were opened by high-pressure water (water pressure: 0.05 MPa, the warp yarn during the opening process The tension in the direction is 90N) to perform fiber opening. The obtained glass cloth after fiber opening has a warp width of 136μm and a weft width of 150μm.

(Implementation Example 6)

Use E glass yarn with an average filament diameter of 3.6 μm, a number of filaments of 38, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 3.6 μm, a number of filaments of 38, and a twist number of 1.0Z. E glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide gray fabric glass cloth with a weaving density of 105 warp yarns/inch and 110 weft yarns/inch. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, the fibers were opened by high-pressure water (water pressure: 0.09 MPa, the warp yarn during the opening process The tension in the direction: 95N) was used for fiber opening. The obtained glass cloth after fiber opening had a warp width of 111μm and a weft width of 126μm.

(Implementation Example 7)

Use E glass yarn with an average filament diameter of 4.0 μm, a number of filaments of 40, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 4.0 μm, a number of filaments of 40, and a twist number of 1.0Z. E glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide gray fabric glass cloth with a weaving density of 96 warp yarns/inch and 96 weft yarns/inch. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, the fibers were opened by high-pressure water (water pressure: 0.09 MPa, the warp yarn during the opening process The tension in the direction: 70N) is applied to the fiber opening process. The warp yarn width of the glass cloth obtained after fiber opening process is 136μm, and the weft yarn width is 151μm.

(Implementation Example 8)

Use E glass yarn with an average filament diameter of 4.0 μm, a number of filaments of 40, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 4.0 μm, a number of filaments of 50, and a twist number of 1.0Z. E glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide gray fabric glass cloth with a weaving density of 96 warp yarns/inch and 96 weft yarns/inch. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, the fibers were opened by high-pressure water (water pressure: 0.08 MPa, the warp yarn during the opening process Directional tension: 125N), The fiber opening process is performed. The warp yarn width of the glass cloth obtained after fiber opening process is 129μm, and the weft yarn width is 179μm.

(Implementation Example 9)

Use a low dielectric glass (boron content 15%) yarn with an average filament diameter of 4.0 μm, a number of filaments of 40, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 4.0 μm and a number of filaments of 40. Low dielectric glass (boron content 15%) yarn with a twist number of 1.0Z is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide gray fabric with a weaving density of 96 warp yarns/inch and 96 weft yarns/inch. Glass cloth. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, the fibers were opened by high-pressure water (water pressure: 0.08 MPa, the warp yarn during the opening process The tension in the direction: 100N) is applied to the fiber opening process. The warp yarn width of the glass cloth obtained after fiber opening process is 116μm, and the weft yarn width is 139μm.

(Example 10)

Use silica glass yarn with an average filament diameter of 3.6 μm, a number of filaments of 38, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 3.6 μm, a number of filaments of 38, and a twist number of 1.0. Z silicon dioxide glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide embryonic glass cloth with a weaving density of 105 warp yarns/inch and 110 weft yarns/inch. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, ultrasonic waves with a frequency of 25 kHz and a power of 0.25 W/ ^cm2 were irradiated in water. The fiber was opened (the tension in the warp direction during the fiber opening process was 120N). The obtained glass cloth after fiber opening had a warp width of 82μm and a weft width of 94μm.

(Comparison Example 1)

The fiber opening process was performed in the same manner as in Example 1, except that the fiber opening process was performed using high-pressure water (water pressure: 0.15Mpa, tension in the warp direction during fiber opening process: 120N) instead of using ultrasonic fiber opening. The obtained glass cloth after fiber opening process had a warp yarn width of 128μm and a weft yarn width of 139μm.

(Comparison Example 2)

The fiber opening process was performed in the same manner as in Example 4, except that the fiber opening process was performed using high-pressure water (water pressure: 0.15Mpa, tension in the warp direction during fiber opening process: 120N). The fiber opening process was performed with the same method as in Example 4. The warp yarn width of the obtained glass cloth after fiber opening process = 137μm, and the weft yarn width = 149μm.

(Comparison Example 3)

Use E glass yarn with an average filament diameter of 3.6 μm, a number of filaments of 40, and a twist number of 0.5Z as the warp yarn. Use an average filament diameter of 3.6 μm, a number of filaments of 40, and a twist number of 0.5Z. E glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide gray fabric glass cloth with a weaving density of 107 warp yarns/inch and 107 weft yarns/inch. Then, after heating at 400°C for 30 hours to remove the astringent, a silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxy Silane (hydrochloride), Chisso Co., Ltd.) was adjusted to a concentration of 10 g/L, extruded using a suction roller, and dried and cured at 120°C for 1 minute. The tension of the glass cloth is set to 20N/m in the warp direction. At the same time, the two ends of the glass cloth in the weft direction are held by a tentering machine and a tension of 5~10N/m is applied in the weft direction to perform fiber opening treatment, thereby producing glass Cloth roll products. The obtained glass cloth after fiber opening has a warp yarn width of 131μm and a weft yarn width of 161μm.

(Comparison Example 4)

The number of filaments of the warp and weft yarns is 40, and the glass type is E glass. The tension of the glass cloth is set to 20N/m in the warp direction by water flow processing with a pressure of 0.5MPa. At the same time, the two ends of the glass cloth in the weft direction are held by a tenter and a tension of 5~10N/m is also applied in the weft direction to perform fiber opening processing. Other than this, the processing is performed in the same way as in Comparative Example 1. The obtained glass cloth after fiber opening processing has a warp yarn width of 111μm and a weft yarn width of 144μm.

(Comparison Example 5)

Use E glass yarn with an average filament diameter of 4.0 μm, a number of filaments of 50, and a twist number of 1.0Z as the warp yarn. Use an average filament diameter of 4.0 μm, a number of filaments of 50, and a twist number of 1.0Z. E glass yarn is used as the weft yarn, and an air-jet loom is used to weave a 1300mm wide gray fabric glass cloth with a weaving density of 95 warp yarns/inch and 95 weft yarns/inch. The glass cloth which had been subjected to heat degreasing at 400°C for 30 hours was immersed in the following treatment solution and then dried by heat. The treatment solution was N-β-(N-vinylbenzylaminoethyl)- γ-aminopropyltrimethoxysilane hydrochloride (Z6032, manufactured by Toray Dow Corning Co., Ltd.) was dispersed in water. Then, the fibers were opened by high-pressure water (water pressure: 0.30 MPa, the warp yarn during the opening process The tension in the direction: 100N) is applied to the fiber opening process. The warp yarn width of the glass cloth obtained after fiber opening process is 140μm, and the weft yarn width is 215μm.

(Comparison Example 6)

The glass cloth product for evaluation was obtained in the same manner as in Comparative Example 5, except that the fiber opening process was performed by applying a tension of 15 N in the weft direction and a tension of 20 N in the warp direction, and irradiating the fiber opening process with ultrasonic waves at a frequency of 25 kHz and a power of 0.72 W/cm ² in water instead of using a jet for fiber opening. Here, as a method of applying tension in the weft direction, an expansion roll was used. The obtained glass cloth after fiber opening had a warp width of 150 μm and a weft width of 125 μm.

(Comparison Example 7)

The evaluation glass cloth product was obtained in the same manner as in Example 1, except that the tension in the warp direction during the fiber opening process was set to 20N. The warp width of the obtained glass cloth after fiber opening process was 123μm, and the weft width was 138μm.

(Comparison Example 8)

The evaluation glass cloth product was obtained in the same manner as in Example 2 except that the tension in the warp direction during the fiber opening process was set to 20N. The warp width of the obtained glass cloth after fiber opening process was 126μm, and the weft width was 141μm.

The measurement results and evaluation results are shown in Table 1 and Table 2.

Claims (12)

A glass cloth is woven by weaving glass yarns including a plurality of glass filaments as warp yarns and weft yarns, wherein the mass of the glass cloth is less than 11.5 g/ ^m2 , the bending rigidity Bw of the warp yarns of the glass cloth is in the range of 0.0030 to 0.0080 gf. ^cm2 /cm, and the bending rigidity Bf of the weft yarns of the glass cloth is in the range of 0.0020 to 0.0050 gf. ^cm2 /cm. For example, the glass cloth of claim 1, wherein the bending stiffness ratio Bw/Bf of the warp yarn and weft yarn of the glass cloth is less than 1.9. A glass cloth is woven by weaving glass yarns including a plurality of glass filaments as warp yarns and weft yarns, wherein the mass of the glass cloth is less than 11.5 g/ ^m2 , the average number of segments of the glass cloth is in the range of 3.0 to 5.0, the warp yarns of the glass cloth have an opening degree of 0.55 to 0.90, and the weft yarns have an opening degree of 0.65 to 0.94. For example, the glass cloth of claim 3, wherein the average fiber opening degree represented by the average value of the fiber opening degree of the above-mentioned warp yarn and the fiber opening degree of the above-mentioned weft yarn is in the range of 0.60 to 0.93. The glass cloth of claim 1 or 3 comprises warp yarns and weft yarns formed by bundling glass filaments with diameters in the range of 2.5 μm to 4.0 μm in a range of 10 to 50 strands, and the weaving density of the warp yarns is in the range of 85 to 150 strands/inch, and the weaving density of the weft yarns is in the range of 85 to 150 strands/inch. For example, the glass cloth in claim 1 or 3, wherein the thickness of the glass cloth is in the range of 8μm~18μm. For example, the glass cloth of claim 1 or 3 is surface treated with a silane coupling agent. The glass cloth of claim 7, wherein the silane coupling agent comprises a silane coupling agent represented by the following general formula (1): X(R) _3-n SiY _n ...(1) (wherein X is an organic functional group comprising one or more amine groups, an organic functional group comprising one or more unsaturated double bond groups having free radical reactivity, or an organic functional group comprising one or more amine groups and one or more unsaturated double bond groups having free radical reactivity, Y is independently an alkoxy group, n is an integer of 1 to 3, and R is independently a group selected from the group consisting of methyl, ethyl and phenyl groups). A prepreg characterized by comprising a glass cloth as described in any one of claims 1 to 8, a thermosetting resin, and an inorganic filler. A printed circuit board, characterized in that it comprises a prepreg as claimed in claim 9. An integrated circuit characterized by comprising a printed circuit board as claimed in claim 10. An electronic machine, characterized in that it includes a printed circuit board as claimed in claim 10.