JP2022063847A - Low dielectric glass cloth, prepreg, and printed wiring board - Google Patents

Abstract

To provide a glass cloth and a glass yarn excellent in insulation reliability, and a prepreg and a printed wiring board which contain the same.SOLUTION: A glass cloth includes a glass yarn made of a plurality of glass filaments as warp and weft. The glass filament has a glass composition containing at least one component selected from the group consisting of SiO2, B2O3, and P2O5. The total of the components is 71 pts. mass or more and 100 pts. mass or less relative to 100 pts. mass of the total components of the glass composition. The glass filament has a chrominance value b* of less than 3.9 in CIE L*a*b* color system.SELECTED DRAWING: None

Description

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

With the development of the information and communication society in recent years, data communication and / or signal processing has become performed at high speed with a large capacity, and the dielectric constant of printed wiring boards used in electronic devices has been remarkably reduced. Therefore, many low-dielectric glass cloths have been proposed for the glass cloths constituting the printed wiring boards.

For example, the low-dielectric glass cloth disclosed in Patent Document 1 contains a large amount of B ₂ O ₃ in the glass composition as compared with the E glass cloth which has been generally used conventionally, and at the same time, other materials such as SiO ₂ etc. The blending amount of the ingredients is also adjusted.

Japanese Unexamined Patent Publication No. 2007-262632

When the B ₂ O ₃ content ratio in the glass thread is increased in order to reduce the dielectric property of the glass cloth, the elastic modulus of the glass thread is lowered, and the glass thread is easily cut during the manufacturing process. Therefore, as described in Patent Document 1, the glass fiber bundle is coated with a sizing agent (also known as glue) at the time of spinning or aging, and after weaving, a treatment called heat cleaning is applied to the glass fiber. The sizing agent, which is an organic substance attached to the bundle, is removed.

As described in Patent Document 1, conventionally, as a heat cleaning method generally performed, for example, a batch type heat cleaning method at 350 to 500 ° C. or a continuous glass woven fabric at a high temperature of 550 to 700 ° C. There is a heat cleaning method in which the material is passed through a heating furnace. However, when such a heat cleaning method is applied to a low-dielectric glass cloth, prepregs having poor insulation reliability may be mixed in the prepregs obtained from the heat-cleaned glass cloth due to combustion residues and the like. I understand.

In view of the above problems, it is an object of the present invention to provide a glass cloth and a glass thread having excellent insulation reliability, and a prepreg and a printed wiring board containing them.

As a result of diligent studies, the present inventors have found that the above problems can be solved by adjusting the hue of a glass cloth having a predetermined glass composition, and have completed the present invention.

That is, the present invention is as follows.
[1]
A glass cloth composed of a glass thread composed of a plurality of glass filaments as a warp and a weft, and the glass filament is selected from the group consisting of SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ in the glass composition. The total of these components is 71 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the total glass composition component, and the chrominance coordinates in the CIE L ^* a ^* b ^* color system. Glass cloth with b ^* less than 3.9.
[2]
The glass cloth according to item [1], wherein the chrominance coordinate b ^* is b ^* <3.6.
[3]
The glass cloth according to item [1], wherein the chrominance coordinate b ^* is b ^* <3.3.
[4]
The glass cloth according to any one of items [1] to [3], wherein the chrominance coordinate b ^* is more than 2.0.
[5]
An alkali metal or an alkaline earth metal is adhered to the surface of the glass cloth, and the alkali metal and the alkaline earth metal are extracted with pure water and determined by an ion chromatograph. The alkali metal and the alkaline soil per surface surface are obtained. The total amount of adhered metal X (mg / m ² ) and the total mass ratio k of SiO ₂ , B ₂ O ₃ and P ₂ O ₅ in the glass composition are as follows:
X [mg / m ² ]> (1.5 [mg / m ² ]) × k
The glass cloth according to any one of items [1] to [4], which satisfies the above conditions.
[6]
The total adhesion amount X (mg / m ² ) and the total mass ratio k are expressed by the following formula:
X [mg / m ² ] <(15.0 [mg / m ² ]) × k
The glass cloth according to item [5], which satisfies the above conditions.
[7]
The item according to any one of items [1] to [6], wherein the content of the alkali metal ion in the glass composition of the glass filament is less than 0.90 part by mass with respect to 100 parts by mass of the total glass composition component. Glass cloth.
[8]
The glass cloth according to any one of the items [1] to [7] and the glass cloth.
The matrix resin impregnated in the glass cloth and
Prepreg including.
[9]
The glass cloth according to any one of the items [1] to [7] and the glass cloth.
The cured product of the matrix resin impregnated in the glass cloth and
Printed wiring board including.
[10]
A glass thread composed of a plurality of glass filaments, wherein the glass filament contains one or more components from the group consisting of SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ in the glass composition, and the components thereof. Is 71 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the total glass composition component, and the content of alkali metal ions in the glass composition of the glass filament is 100 parts by mass of the total glass composition component. It is less than 0.90 parts by mass, and alkali metal or alkaline earth metal is adhered to the surface of the glass thread. Alkali metal and alkaline earth per surface surface obtained by extraction with pure water and ion chromatograph. The total amount of metal adhered X (mg / m ² ) and the total mass ratio k of SiO ₂ , B ₂ O ₃ and P ₂ O ₅ in the glass composition are as follows.
X [mg / m ² ]> (1.5 [mg / m ² ]) × k
Meet, glass thread.
[11]
The total adhesion amount X (mg / m ² ) and the total mass ratio k are expressed by the following formula:
X [mg / m ² ] <(15.0 [mg / m ² ]) × k
The glass thread according to item [10], which satisfies the above conditions.

According to the present invention, a glass cloth and a glass thread having excellent insulation reliability can be provided, and the insulation reliability of a prepreg or a printed wiring board containing them is also excellent.

Hereinafter, embodiments of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited thereto, and various modifications can be made without departing from the gist thereof. Is. In the present specification, the dielectric constant means a frequency of 10 GHz unless otherwise specified.

<Glass cloth>
The glass cloth according to the present embodiment is configured by using a glass thread composed of a plurality of glass filaments as a warp and a weft, and the glass filament has SiO ₂ , B ₂ O ₃ , and P ₂ O in the glass composition. It contains one or more components selected from the group consisting of ₅ , and the total of these components is 71 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the total glass composition component, and CIE L ^* a ^* b ^*. The chrominance coordinate b ^* value is smaller than 3.9 in the color system. Further, the chrominance coordinate b ^* value is preferably larger than 2.0. Further, the total content of one or more components selected from the group consisting of SiO ₂ , B ₂ O ₃ and P ₂ O ₅ in the glass composition of the glass filament is preferably the total content of 100 parts by mass of the total glass composition components. It is 72 parts by mass or more and 90 parts by mass or less, more preferably 72.5 parts by mass or more and 85 parts by mass or less.

<Hue>
In the CIE L ^* a ^* b ^* color system of the glass cloth according to the present embodiment, the chrominance coordinate b ^* is a value smaller than 3.9, preferably a value exceeding 2.0. The L ^* a ^* b ^* color system was standardized by the International Commission on Illumination (CIE) in 1976 and is measured according to JIS Z8781 (2016). In the L ^* a ^* b ^* color system, the chrominance coordinates b ^* represent the hue from the blue direction (minimum value: -60) to the yellow direction (maximum value: +60).

According to the present invention, it has been found that at least a part of the glass cloth structure having excellent reliability is in the 2.0 <b ^* value <3.9 of the L ^* a ^* b ^* color system. Although not bound by theory, the yellowing component in conventional low-dielectric glass cloth may interfere with the surface treatment of the glass cloth with the silane coupling agent in the subsequent process. However, it is considered that the glass cloth of 2.0 <b ^* <3.9 in the L ^* a ^* b ^* color system tends to have less such yellowing or the surface treatment is performed efficiently. Be done.

The L ^* a ^* b ^* color system b ^* value of the glass cloth is 3.6 or less and less than 3.6 (b ^* <3.6), 3.3 or less from the viewpoint of further improving reliability. It is preferably less than 3.3 (b ^* <3.3) or 3.0 or less. Further, the lower limit of the b ^* value is preferably a value exceeding 2.0 from the viewpoint of suppressing fluffing of the glass cloth.

In the CIE L ^* a ^* b ^* color system of the glass cloth, the chrominance coordinates b ^* suppress yellowing by increasing the temperature or time condition of the heat cleaning process described later, and / or the glass cloth described later. The value can be adjusted to less than 3.9 by the adhesion treatment of.

<Glass composition>
The glass composition according to this embodiment will be described below. In the composition of the glass thread according to the present embodiment, the total mass of silicon (Si) and boron (B) converted into SiO ₂ and B ₂ O ₃ is 70% by mass or more based on the mass of the glass thread. .. When the total content of Si and B in terms of SiO ₂ and B ₂ O ₃ is 70% by mass or more, the dielectric constant tends to decrease. From such a viewpoint, in the composition of the glass yarn, the total content of Si and B in terms of SiO ₂ , B ₂ O ₃ is preferably 72.5% by mass or more, or 75% by mass or more. The upper limit of the total content of Si and B in terms of SiO ₂ , B ₂ O ₃ can be less than 100% by mass, and / or the Si content is less than 100% by mass in terms of SiO ₂ . be able to.

The Si content of the glass thread is preferably 40% by mass or more, more preferably 40% by mass or more, as long as the total content of Si and _B in terms of SiO ₂ and B ₂ O ₃ is 70% by mass or more. , 45% by mass or more, 47% by mass or more, or 48% by mass or more, and the upper limit thereof can be less than 100% by mass or 99.9% by mass or less.

Silicon (Si) is a component that forms the skeleton structure of glass thread, and when the Si content is 40% by mass or more in terms of SiO ₂ , the strength of the glass thread is further improved, and the manufacturing process of glass cloth and glass In a post-process such as manufacturing a prepreg using a cloth, the breakage of the glass cloth tends to be further suppressed. Further, when the Si content is 40% by mass or more in terms of SiO ₂ , the dielectric constant of the glass cloth tends to be further lowered.

The B content of the glass yarn is preferably 15% by mass to 30% by mass in terms of B ₂ O ₃ as long as the total content of Si and B in terms of SiO ₂ and B ₂ O ₃ is 70% by mass or more. Yes, more preferably 17% by mass to 28% by mass, still more preferably 17.5% by mass to 25% by mass. When the B content is 15% by mass or more, the dielectric constant tends to be further lowered. Further, when the B content is 30% by mass or less, the hygroscopicity is improved and the insulation reliability tends to be further improved.

Further, the glass filament according to the present embodiment has Fe, F, Al, Ca, Mg, as long as the total content of Si and B in the glass composition is 70% by mass or more in terms of SiO ₂ , B ₂ O ₃ . It may contain P, Na, K, Ni, Ti, Zn, or a combination thereof.

The Al content of the glass yarn is preferably 12 to 16% by mass in terms of Al ₂ O ₃ from the viewpoint of electrical characteristics or strength.

The P content of the glass yarn is preferably 0.1% by mass to 6% by mass, and more preferably _2.0 % by mass to _5.5 % by mass in terms of P2O5. When the P content is 0.1% by mass or more in terms of P ₂ O ₅ , the dielectric constant tends to be further lowered. Further, since the P content is 6% by mass or less in terms of P ₂ O ₅ , the glass cloth passes through the squeeze roll or the nip roll in a wet state in the fiber opening step or the surface treatment step at the time of manufacturing the glass cloth. At that time, it tends to be less likely to break. In addition, phase separation during the production of the glass filament is suppressed, and the moisture absorption resistance of the obtained glass filament is further improved. As a result, the obtained printed wiring board is not easily affected by the usage environment in a high humidity environment, and the environment dependence of the dielectric constant can be reduced.

The Ca content of the glass yarn is preferably 1% by mass to 5% by mass, preferably 2% by mass to 4% by mass in terms of CaO. When the Ca content is 1% by mass or more in terms of CaO, the viscosity at the time of melting is further lowered in the process of manufacturing the glass filament, and the glass fiber having a more uniform glass composition tends to be obtained. Further, when the Ca content is 5% by mass or less in terms of CaO, the dielectric constant tends to be further improved.

The Mg content of the glass yarn is preferably 0.01% by mass to 5% by mass in terms of MgO. When the Mg content is 5% by mass or less in terms of MgO, when the glass cloth passes through a squeeze roll or a nip roll in a wet state in a fiber opening step or a surface treatment step at the time of manufacturing glass cloth, It tends to be less likely to break. In addition, phase separation during the production of the glass filament is suppressed, and the moisture absorption resistance of the obtained glass filament is further improved. As a result, the obtained printed wiring board is not easily affected by the usage environment in a high humidity environment, and the environment dependence of the dielectric constant can be reduced.

The contents of Si, B, Al, P, Ca and Mg can be adjusted according to the amount of raw materials used for producing the glass filament. In addition, each content described above can be measured by inductively coupled plasma (ICP) emission spectroscopic analysis by extracting the glass thread from the glass cloth. As the ICP emission spectroscopic analyzer, for example, PS3520 VDD II manufactured by Hitachi High-Tech Science Corporation can be used.

Specifically, the Si content, the B content, and the total content of Si and B were determined by melting the weighed glass cloth sample with sodium carbonate and then dissolving it with dilute nitric acid to determine the volume. Can be measured and obtained by ICP emission spectroscopic analysis.

Further, the Al content, Ca content, and Mg content were obtained by thermally decomposing the weighed glass cloth sample with sulfuric acid, nitric acid, and hydrogen fluoride, and then dissolving it in dilute nitric acid to determine the volume. Can be measured and obtained by ICP emission spectroscopic analysis.

<Structure>
The glass yarn is obtained by bundling a plurality of glass filaments and twisting them as necessary, and the glass cloth is obtained by weaving the above glass yarns as warp and weft. Glass threads are classified into multifilaments and glass filaments are classified into monofilaments.

The average radius of the glass filaments constituting the warp and weft is independently, preferably 2.5 μm to 9 μm, more preferably 3.0 μm to 7.5 μm, and further preferably 3.5 μm to 5. It is 4 μm. When the average diameter of the glass filament is within the above range, the workability tends to be further improved when the obtained substrate is processed by a mechanical drill, a carbon dioxide gas laser, or a UV-YAG laser. Therefore, it is possible to realize a thin and high-density mounted printed wiring board. In particular, when the average radius is 5.4 μm or less, the surface area per unit volume increases and the hygroscopic viscous material derived from the sizing agent easily adheres, so that the effect of improving the insulation reliability of the present embodiment is more important. It becomes. Further, when the average radius is 2.5 μm or more, breakage occurs when the glass cloth passes through the squeeze roll or the nip roll in a wet state in the glass cloth manufacturing process including the fiber opening step or the surface treatment step. It tends to be difficult. Further, even in a post-process such as manufacturing of a prepreg, when the glass cloth is passed through the slit for the purpose of controlling the amount of the resin impregnated in the glass cloth, the glass cloth tends to be less likely to break.

The driving density of the warp and weft constituting the glass cloth is preferably 30 threads / inch to 120 threads / inch, more preferably 40 threads / inch to 110 threads / inch, and further preferably 50 threads / inch to. It is 100 lines / inch.

The thickness of the glass cloth is preferably 8 μm to 100 μm, more preferably 10 μm to 70 μm, and further preferably 12 μm to 50 μm. When the thickness of the glass cloth is within the above range, a thin and relatively high-strength glass cloth tends to be obtained.

The cloth weight (graining) of the glass cloth is preferably 8 g / m ² to 250 g / m ² , more preferably 8 g / m ² to 100 g / m ² , and further preferably 8 g / m ² to 50 g / m. It is ² , and particularly preferably 8 g / m ² to 35 g / m ² .

The woven structure of the glass cloth is not particularly limited, and examples thereof include woven structures such as plain weave, Nanako weave, satin weave, and twill weave. Of these, a plain weave structure is more preferable.

<Adhesion treatment>
The glass cloth according to the present embodiment is preferably adhered with an alkali metal or an alkaline earth metal-containing compound, and more preferably an alkali metal or an alkaline earth metal-containing compound is adhered to the surface thereof. Adhesion treatment with an alkali metal or alkaline earth metal-containing compound facilitates adjusting the chrominance coordinate b ^* value to less than 3.9 in the CIE L ^* a ^* b ^* color system of the glass cloth. Further, in the glass cloth manufacturing process, if the alkali metal or alkaline earth metal-containing compound is adhered before the degluing (heat cleaning) step for heat-removing the sizing agent, yellowing after heat cleaning is performed. Can be reduced.

The alkali metal or alkaline earth metal-containing compound adhering to the glass thread and the glass cloth preferably contains an alkali metal from the viewpoint of improving the reliability of the glass cloth, and from the viewpoint of further improving the reliability of the glass cloth. It is more preferable to contain sodium (Na) from the above.

Examples of the Na-containing compound attached to the glass cloth include, but are not limited to, sodium chloride (NaCl) and sodium carbonate (Na ₂ CO ₃ ).

The alkaline earth metal-containing compound adhering to the glass cloth preferably contains Mg, and examples thereof include, but are not limited to, MgCl ₂ .

The total amount of alkali metal and alkaline earth metal attached to the glass cloth can be measured by extraction into pure water, for example, by measuring the amount of elution into distilled water. An ion chromatograph can be used to detect the amount of elution.

From the measured values by the above method, the amount of alkali metal and alkaline earth metal attached per glass cloth surface area can be determined. The surface area of the glass cloth is obtained from the fiber diameter used and the number of fibers per glass thread. The obtained numerical value X satisfies the following formula including the mass ratio k including SiO ₂ , B ₂ O ₃ and P ₂ O ₅ in the glass composition from the viewpoint of adjusting the b ^* value to an appropriate value. Is preferable.
X [mg / m ² ]> (1.5 [mg / m ² ]) × k
This numerical value X is more preferably 2.0 × k or more, and further preferably 2.5 × k or more.

Further, in the above formula, the lower limit of the adhesion amount X is preferably less than 15.0 × k from the viewpoint of maintaining the breaking strength.

The above value of 1.5 × k was woven using a glass type: A (listed in Table 2 below) and 200 fibers at a warp weaving density of 60 / inch and a weft weaving density of 58 / inch. It corresponds to about 0.024 parts by mass with respect to the glass cloth.

The degree of yellowing changes depending on the ratio of SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ in the glass composition, and the required amount of adhesion changes accordingly. Although not bound by theory, the proportion of SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ in the composition increases when the glass is made low-dielectric, resulting in an increase in the proportion of alkaline earth metals. It is possible that it is decreasing.

The adhesion treatment is not particularly limited, and examples thereof include a method of attaching an alkali metal and / or an alkaline earth metal to the glass yarn and then weaving the glass cloth, or a method of attaching the glass cloth to the weaved glass cloth. The method of adhesion is not limited, but is a method of applying an aqueous solution of an alkali metal and / or an alkaline earth metal compound to a glass cloth or a glass thread by a two-fluid nozzle, or a method of immersing the glass cloth or the glass thread in the aqueous solution and drying it. The method etc. can be mentioned.

Alternatively, a method of adding an alkali metal and / or an alkaline earth metal to the raw material glass can be considered, but from the viewpoint of dielectric constant and breaking strength, a form in which the additive component is present only on the surface is more preferable. Further, a method of adding an alkali metal and / or an alkaline earth metal to a glue to coat the glass thread is also conceivable, but from the viewpoint of the effect of the present invention, the form in which the additive component is present on the surface of the glass cloth is considered. Is more preferable.

The content of the alkali metal ion in the glass composition of the glass filament according to the present embodiment is 0.90 mass by mass with respect to 100 parts by mass of the total glass composition component from the viewpoint of appropriately exerting the effect described above. It is preferably less than 0 parts by mass, and more preferably more than 0 parts by mass and less than 0.90 parts by mass.

<Surface treatment>
The glass cloth surface can be treated with a surface treatment agent. The surface treatment agent is not particularly limited, and examples thereof include a silane coupling agent, and water, an organic solvent, an acid, a dye, a pigment, a surfactant and the like may be used in combination, if necessary.

The silane coupling agent is not particularly limited, but for example, the following formula (1):
X (R) _3-n SiY _n ... (1)
{In the formula, X is an organic functional group having at least one of an amino group and an unsaturated double bond group, Y is an independently alkoxy group, and n is 1 or more and 3 or less. It is an integer, and R is a group independently selected from the group consisting of a methyl group, an ethyl group and a phenyl group}.
Examples thereof include the compounds indicated by.

In the formula (1), X is preferably an organic functional group having at least 3 or more of an amino group and an unsaturated double bond group, and X is at least one of an amino group and an unsaturated double bond group. It is more preferable that the organic functional group has four or more.

As the alkoxy group in the formula (1), an alkoxy group having 5 or less carbon atoms is preferable from the viewpoint of stabilizing the glass cloth.

Specific examples of the silane coupling agent include N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane and its hydrochloride, N-β- (N-vinylbenzylaminoethyl)-. γ-Aminopropylmethyldimethoxysilane and its hydrochloride, N-β- (N-di (vinylbenzyl) aminoethyl) -γ-aminopropyltrimethoxysilane and its hydrochloride, N-β- (N-di (vinyl)) Benzyl) Aminoethyl) -N-γ- (N-vinylbenzyl) -γ-aminopropyltrimethoxysilane and its hydrochloride, N-β- (N-benzylaminoethyl) -γ-aminopropyltrimethoxysilane and its hydrochloride Hydrochloride, N-β- (N-benzylaminoethyl) -γ-aminopropyltri ethoxysilane and its hydrochloride, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) Examples thereof include aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltrimethoxysilane, metharoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane and the like. Of these, a single substance or a mixture thereof may be used.

The molecular weight of the silane coupling agent is preferably 100 to 600, more preferably 150 to 500. It is also preferable to use two or more kinds of silane coupling agents having different molecular weights. By treating the surface of the glass yarn with two or more kinds of silane coupling agents having different molecular weights, the density of the surface treatment agent on the surface of the glass cloth is increased, and the reactivity with the matrix resin tends to be further improved. ..

<Glass thread>
A glass thread capable of adjusting the CIE L ^* a ^* b ^* chrominance coordinates b ^* in the color system of the glass cloth described above to less than 3.9 is also an aspect of the present invention. That is, the glass thread according to the present embodiment can have the same properties (however, excluding the chrominance coordinates b ^* ) and the configuration as those of the glass cloth described above.

More specifically, the glass thread according to the present embodiment is composed of a plurality of glass filaments, and the glass filament is one or more from the group consisting of SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ in the glass composition. The total of these components is 71 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the total glass composition component, and the content of alkali metal ions in the glass composition of the glass filament is total glass. It is less than 0.90 parts by mass with respect to 100 parts by mass of the composition component, and alkali metal or alkaline earth metal is adhered to the surface of the glass thread. The total amount of adhesion X (mg / m ² ) of alkali metal and alkaline earth metal and the total mass ratio k of SiO ₂ , B ₂ O ₃ and P ₂ O ₅ in the glass composition are as follows:
X [mg / m ² ]> (1.5 [mg / m ² ]) × k
It is characterized by satisfying.

For glass yarn, the total amount of one or more components from the group consisting of SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ , the alkali metal ion content, and the total adhesion amount X (mg / m ² ) are totaled. The preferred range of the relationship of the mass ratio k may be the same as the range described for the glass cloth. Above all, the total adhesion amount X (mg / m ² ) of the alkali metal and the alkaline earth metal per surface area of the glass thread obtained by extracting with pure water from the surface of the glass thread and determining by ion chromatograph, and SiO ₂ in the glass composition. , B ₂ O ₃ and P ₂ O ₅ have the following formula:
X [mg / m ² ] <(15.0 [mg / m ² ]) × k
It is preferable to further satisfy the relationship represented by.

<Physical characteristics>
The dielectric constant of the glass cloth according to the present embodiment is preferably less than 5.0, more preferably 4.9 or less or 4 at a frequency of 10 GHz from the viewpoint of large capacity and high speed data communication and signal processing. It is 8.8 or less, more preferably 4.7 or less, 4.5 or less, 4.4 or less, 4.0 or less, or 3.7 or less.

The breaking strength of the glass cloth according to the present embodiment is preferably 180 N / mm ^{2 or more, more preferably 200 N / mm 2 or} more, and further preferably 220 N / mm from the viewpoint of suppressing fluffing of the glass cloth. ² or more.

<Manufacturing method of glass cloth>
The method for manufacturing the glass cloth according to the present embodiment is not particularly limited, and for example, a weaving step of weaving a glass thread to obtain a glass cloth, a fiber opening step of opening the glass thread of the glass cloth, and a glass cloth. Examples thereof include a method having a degluing step of removing a sizing agent (also known as a glue) adhering to the glass thread. Further, if necessary, it may have a surface treatment step using a surface treatment agent such as a silane coupling agent.

The weaving method is not particularly limited as long as the weft and warp are folded so as to have a predetermined weaving structure. The fiber-opening method is not particularly limited, and examples thereof include a method of fiber-spreading with spray water (high-pressure water-spreading), vibro washer, ultrasonic water, mangle, and the like.

Further, the degluing method is not particularly limited, and examples thereof include a method of heating and removing the sizing agent. The sizing agent is used for the purpose of protecting the glass yarn from breaking in the weaving process or the like. Such a sizing agent is not particularly limited, and examples thereof include a starch-based binder and a polyvinyl alcohol-based binder. The temperature at which the sizing agent is removed by heating is preferably 300 ° C. to 500 ° C., more preferably 330 ° C. to 450 ° C. from the viewpoint of sufficiently removing the sizing agent while maintaining the breaking strength. , More preferably 350 ° C to 430 ° C.

Further, with respect to the conditions for heat removal, a temperature higher than the above temperature range may be used for the purpose of adjusting the CIE L ^* a ^* b ^* color system chrominance coordinates b ^* , and the temperature is preferably 500 ° C. It is about 800 ° C., more preferably 550 ° C. to 750 ° C., and even more preferably 600 ° C. to 700 ° C.

When the batch type heat cleaning method is adopted for heat removal, the heating time is preferably 6 to 66 hours, more preferably 10 to 50 hours, and further preferably 15 to 45 hours. If the heating time is short, the b ^* value will be larger than the target range, and if it is long, the b ^* value will be smaller than the target range.

From the viewpoint of more preferably controlling the b ^* value, it is processed for a longer time than the continuous heat cleaning method in which the winding body of the glass fiber woven fabric is continuously passed through a heating furnace and processed in a short time. The batch type heat cleaning method is preferable.

In addition, examples of the surface treatment method include a method in which a surface treatment agent containing a surface treatment agent (for example, a silane coupling agent) is brought into contact with a glass cloth and dried. The contact of the surface treatment agent with the glass cloth is a method of immersing the glass cloth in the surface treatment agent, a method of applying the surface treatment agent to the glass cloth using a roll coater, a die coater, a gravure coater, or the like. Can be mentioned. The method for drying the surface treatment agent is not particularly limited, and examples thereof include hot air drying or a drying method using electromagnetic waves.

<Prepreg>
The prepreg according to the present embodiment has the glass cloth described above and the matrix resin composition impregnated in the glass cloth. The prepreg containing the glass cloth has improved insulation reliability and a high yield of the final product. In addition, since it has excellent dielectric properties and excellent hygroscopicity, it can also have the effect of being able to provide a printed wiring board that is less affected by the usage environment, particularly that the dielectric constant fluctuates in a high humidity environment.

The prepreg according to the present embodiment can be manufactured according to a conventional method. For example, the glass cloth of the present embodiment is impregnated with a varnish obtained by diluting a matrix resin such as an epoxy resin with an organic solvent, and then the organic solvent is volatilized in a drying furnace to put the thermosetting resin in a B stage state (half). It can be manufactured by curing it to a cured state).

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

In addition, the matrix resin composition contains inorganic fillers such as silica and aluminum hydroxide in the resin; flame retardants such as bromine-based, phosphorus-based and metal hydroxides; other silane coupling agents; heat stabilizers; antistatic agents. It may contain an ultraviolet absorber; a pigment; a colorant; a lubricant, and the like.

<Printed wiring board>
The printed wiring board according to the present embodiment includes the glass cloth described above and a cured product of the matrix resin impregnated in the glass cloth. The printed wiring board according to the present embodiment not only improves reliability, but also increases the yield of the final product, has excellent dielectric properties, and can be adapted to the usage environment.

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

<Example 1>
A glass yarn having the composition shown in Table 2 glass type: A (average diameter of filament: 7.0 μm, number of filaments: 200) is woven by an air jet room, and the driving density of warp and weft is 60 yarns / inch, respectively. , 58 pieces / inch, and a glass cloth having a thickness of 91 μm was obtained. Next, a heat cleaning treatment was carried out at 530 ° C. for 12 hours by heating, and a fiber opening step was carried out by high-pressure water spraying to obtain an intermediate of a glass cloth having a width of 1285 mm and a length of 2000 m. Subsequently, the intermediate was surface-treated with a silane coupling agent to prepare a glass cloth.

<Example 2>
A glass cloth was obtained in the same manner as in Example 1 except that the conditions of the heat cleaning treatment were changed to 630 ° C. for 24 hours.

<Examples 3 to 5>
A glass yarn having the composition shown in Table 2 glass type: A (average diameter of filament: 7.0 μm, number of filaments: 200) is woven by an air jet room, and the driving density of warp and weft is 60 yarns / inch, respectively. , 58 pieces / inch, and a glass cloth having a thickness of 91 μm was obtained. Next, an aqueous solution prepared by dissolving sodium hydrogen carbonate (NaHCO ₃ ) in water was applied to a glass cloth using a two-fluid nozzle. The amounts of the compounds shown in Table 1 were extracted from the glass cloth after hot air drying. Next, a heat cleaning treatment was carried out at 400 ° C. for 24 hours by heating, and a fiber opening step was carried out by high-pressure water spraying to obtain an intermediate of a glass cloth having a width of 1285 mm and a length of 2000 m. Finally, a glass cloth was prepared by surface-treating the intermediate with a silane coupling agent.

<Example 6>
Table 2 A glass cloth was produced in the same manner as in Example 1 except that the glass type: B was used and the heat cleaning time was set to 24 hours.

<Example 7>
Table 2 A glass cloth was prepared in the same manner as in Example 2 except that B was used.

<Examples 8 to 10>
Table 2 Glass cloth was prepared in the same manner as in Examples 3 to 5 except that B was used.

<Comparative Example 1>
A glass cloth was obtained in the same manner as in Example 1 except that the temperature condition of the heat cleaning treatment was changed to 400 ° C. and the time condition was changed to 24 hours.

<Comparative Example 2>
A glass cloth was obtained in the same manner as in Example 6 except that the temperature condition of the heat cleaning treatment was changed to 400 ° C.

<Comparative Example 3>
As for the heat cleaning treatment, a continuous heat cleaning method was adopted, and a glass cloth was obtained in the same manner as in Example 1 except that the glass cloth was heated at 540 ° C. for 90 seconds and then at 650 ° C. for 80 seconds.

<Comparative Example 4>
As for the heat cleaning treatment, a continuous heat cleaning method was adopted, and a glass cloth was obtained in the same manner as in Example 6 except that the glass cloth was heated at 540 ° C. for 90 seconds and then at 650 ° C. for 80 seconds.

<Physical characteristics of glass cloth>
The physical properties of the glass cloth, specifically, the thickness of the glass cloth, the diameter of the warp and the filament constituting the weft, the number of filaments, and the driving density (weaving density) of the warp and the weft were measured in accordance with JIS R3420.

<Composition of glass thread>
The composition constituting the glass yarn was measured by ICP emission spectroscopic analysis. Specifically, the Si content and the B content are determined by melting the weighed glass cloth sample with sodium carbonate, dissolving it with dilute nitrate, and measuring the obtained sample by ICP emission spectroscopic analysis. I got it. The Al content, Ca content, P content, Ti content and Mg content are determined by heat-decomposing the weighed glass cloth sample with sulfuric acid, nitric acid and hydrogen fluoride, and then dissolving it with dilute nitric acid. The obtained sample was measured by ICP emission spectroscopic analysis. As the ICP emission spectroscopic analyzer, PS3520 VDD II manufactured by Hitachi High-Tech Science Corporation was used.

<CIE L ^* a ^* b ^* Color system>
The L ^* a ^* b ^* color system of the glass cloth was measured according to JIS Z8781 (2005) using a spectrocolorimeter (CM-2600d, manufactured by Konica Minolta). The b ^* value was measured by stacking glass cloths on a white plate as a reference (control) so as to have a thickness of 2.0 mm or more, and used the average value of the five measured values.

<Permittivity>
As described later, a substrate was prepared so that the resin content per 100% by mass of the prepreg was 60% by mass, and the copper foil was removed to obtain a sample for dielectric constant evaluation. The dielectric constant of the obtained sample at a frequency of 1 GHz was measured using an impedance analyzer (manufactured by Agilent Technologies). From the obtained substrate dielectric constant, the dielectric constant of the glass cloth was calculated based on the volume fraction of the glass cloth and the resin dielectric constant of 2.5.

<Elution amount of alkali metals and alkaline earth metals>
1.42 parts by mass of glass cloth was completely immersed in 100 parts by mass of distilled water at room temperature (25 ° C.) and left for 5 hours (so that the whole was immersed), and the water after leaving (adhesion on the surface was dissolved). The solution) was measured by an ion chromatograph (manufactured by Nippon Dionex) to obtain the amount of alkali metal ions and alkaline earth metal ions eluted from the glass cloth. The blank was measured with distilled water only. From the obtained measured values, the amount of adhesion per surface area of the glass cloth was calculated based on the average diameter of the filaments and the number of filaments.

<Method of manufacturing laminated board>
Epoxy resin varnish (40 parts by mass of low brominated bisphenol A type epoxy resin, 10 parts by mass of o-cresol type novolak epoxy resin, 50 parts by mass of dimethylformamide, 1 part by mass of dicyandiamide) was added to the glass cloths obtained in the above Examples and Comparative Examples. And 0.1 part by mass of 2-ethyl-4-methylimidazole) were impregnated and dried at 160 ° C. for 2 minutes to obtain a prepreg. This prepreg was layered, and copper foil having a thickness of 12 μm was layered on top and bottom, and heated and pressed at 180 ° C. and 40 kg / cm ² for 60 minutes to obtain a laminated board.

<Evaluation method of insulation reliability of laminated board>
As described above, a laminated board is manufactured so as to have a thickness of 1.0 mm, and a wiring pattern in which through holes are arranged at intervals of 0.30 mm is prepared on the copper foils on both sides of the laminated board to evaluate the insulation reliability. Samples were obtained. A voltage of 50 V was applied to the obtained sample in an atmosphere of a temperature of 85 ° C. and a humidity of 85% RH, and the change in resistance value was measured. At this time, when the resistance became less than 1 MΩ within 500 hours after the start of the test, it was counted as an insulation defect. The same measurement was performed on 10 samples, and the ratio of the samples that did not have insulation failure in 10 samples was calculated.

<Measurement of breaking strength>
The amount of elongation when tension is applied to the glass cloth in the warp or weft direction is in accordance with the method described in JIS R3420, General Test Method for Glass Test, 7.4.2 (in the case of cloth). Measurement was performed by prescription.

As is clear from the results in Table 3, the laminated board made from the low-dielectric glass cloth adjusted with the chrominance coordinates b ^* of the present invention showed higher reliability than the comparative example. In particular, the low-dielectric glass cloth coated with the alkali metal or alkaline earth metal of Examples 3 to 5 and Examples 8 to 10 showed the best reliability.

Claims (11)

A glass cloth composed of a glass thread composed of a plurality of glass filaments as a warp and a weft, and the glass filament is selected from the group consisting of SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ in the glass composition. The total of these components is 71 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the total glass composition component, and the chrominance coordinates in the CIE L ^* a ^* b ^* color system. A glass cloth in which b ^* is less than 3.9. The glass cloth according to claim 1, wherein the chrominance coordinate b ^* is b ^* <3.6. The glass cloth according to claim 1, wherein the chrominance coordinate b ^* is b ^* <3.3. The glass cloth according to any one of claims 1 to 3, wherein the chrominance coordinate b ^* is more than 2.0. An alkali metal or an alkaline earth metal is adhered to the surface of the glass cloth, and the alkali metal and the alkaline earth metal are extracted with pure water and determined by an ion chromatograph. The alkali metal and the alkaline soil per surface surface are obtained. The total amount of adhered metal X (mg / m ² ) and the total mass ratio k of SiO ₂ , B ₂ O ₃ and P ₂ O ₅ in the glass composition are as follows:
X [mg / m ² ]> (1.5 [mg / m ² ]) × k
The glass cloth according to any one of claims 1 to 4, which satisfies the above conditions. The total adhesion amount X (mg / m ² ) and the total mass ratio k are expressed by the following formula:
X [mg / m ² ] <(15.0 [mg / m ² ]) × k
The glass cloth according to claim 5. The glass cloth according to any one of claims 1 to 6, wherein the content of alkali metal ions in the glass composition of the glass filament is less than 0.90 parts by mass with respect to 100 parts by mass of the total glass composition component. The glass cloth according to any one of claims 1 to 7.
The matrix resin impregnated in the glass cloth and
Prepreg including. The glass cloth according to any one of claims 1 to 7.
The cured product of the matrix resin impregnated in the glass cloth and
Printed wiring board including. A glass thread composed of a plurality of glass filaments, wherein the glass filament contains one or more components from the group consisting of SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ in the glass composition, and the components thereof. Is 71 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the total glass composition component, and the content of alkali metal ions in the glass composition of the glass filament is 100 parts by mass of the total glass composition component. It is less than 0.90 parts by mass, and alkali metal or alkaline earth metal is adhered to the surface of the glass thread. Alkali metal and alkaline earth per surface surface obtained by extraction with pure water and ion chromatograph. The total amount of metal adhered X (mg / m ² ) and the total mass ratio k of SiO ₂ , B ₂ O ₃ and P ₂ O ₅ in the glass composition are as follows.
X [mg / m ² ]> (1.5 [mg / m ² ]) × k
Meet, glass thread. The total adhesion amount X (mg / m ² ) and the total mass ratio k are expressed by the following formula:
X [mg / m ² ] <(15.0 [mg / m ² ]) × k
The glass thread according to claim 10.