JPH11255908A - Printed circuit board substrate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed circuit board substrate having excellent properties such as excellent homogeneity, excellent resin permeability, excellent mechanical performances, excellent heat resistance and excellent dimensional stability, and to provide a method for efficiently producing the same. SOLUTION: This printed circuit board substrate comprises a wet sheet comprising (A) melt liquid-crystalline polyester fibers having a melting point of >=290 deg.C and (B) a melt liquid-crystalline polyester binder having a melting point of >=290 deg.C, wherein the component A is fixed to the component B. The component B has a film-like shape having >=5 pores/mm<2> wherein each pore has an opening area of 400-10,000 μm<2> in the wet sheet. This method for producing the printed circuit board substrate comprises subjecting paper materials containing (A) the melt liquid-crystalline polyester fibers having a melting point of >=290 deg.C and (B0 ) a melt liquid-crystalline polyester fibrous binder having a melting point of <290 deg.C to a wet paper-making process, heating the made sheet under non-pressurization to melt and convert the component B0 into (B) the filmy melt liquid-crystalline polyester binder having >=5 holes/mm<2> (wherein each hole has an opening area of 400-10,000 μm<2> ) and simultaneously fix the component A, and subsequently subjecting the component B to a solid phase polymerization to raise the melting point of the component B to >=290 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board base material and a method for manufacturing the same, as well as a printed wiring board and a printed wiring board.

[0002]

2. Description of the Related Art Glass fiber fabrics have long been used as substrates for printed wiring boards. However, glass fibers have a drawback that they have a high dielectric constant and are heavy. In recent years, the use of liquid crystal aramid fibers has been studied, but aramid fibers have high hygroscopicity and are not sufficiently satisfactory as a printed wiring board requiring excellent electrical insulation.

In view of the above, it has been proposed to use a molten liquid crystalline polyester fiber having a low dielectric constant, a low specific gravity, and a low moisture absorption as a substrate for a printed wiring board. For example, Japanese Patent Application Laid-Open No. 62-36892 describes a printed wiring board based on a woven fabric made of a molten liquid crystalline polyester fiber, and a thin woven fabric is manufactured using the molten liquid crystalline polyester fiber. In this case, there is a problem that the processability is low and the manufacturing cost is high. In addition, the obtained printed wiring board base material has poor homogeneity and low workability such as resin impregnation. It has also been proposed to use a dry nonwoven fabric obtained by a spunlace method (water entanglement method) as a base material for a printed wiring board (WO96 / 1530).
No. 6). However, this dry nonwoven fabric has low mechanical properties and homogeneity, and in particular, becomes more unfavorable as a substrate for a printed wiring board, because the thinner one has more adverse effects such as uneven thickness.

[0004]

On the other hand, a wet nonwoven fabric (wet papermaking) made of a molten liquid crystalline polyester fiber has excellent mechanical performance, high homogeneity, and has no unevenness even when it is made thin. For example, JP-A-7-48718 and JP-A-8-170295 describe papers obtained by wet-making a liquid crystalline polyester short fiber and a molten liquid crystalline polyester pulp. However, this paper is still inadequate in terms of resin impregnating properties and heat resistance, and such a conventional method requires a base material having excellent properties such as homogeneity, resin impregnating properties, mechanical performance, and heat resistance. No material was obtained.

[0005] That is, in order to improve the mechanical performance, homogeneity, and the like of the nonwoven fabric, a heat calendering process is generally performed. When such a process is performed, the surface of the nonwoven fabric is formed into a film by thermal compression, and the pore size is reduced. The number of pores which become minute and which can be impregnated with resin is drastically reduced. For this reason, the resin impregnating property becomes low, and it becomes difficult to impregnate the resin with the entire nonwoven fabric, and a problem arises in that a portion not impregnated with the resin is necessarily formed inside the nonwoven fabric. If there are many voids that are not impregnated with the resin, the electrical insulation becomes unstable during moisture absorption, and the solder heat resistance becomes poor.
It becomes insufficient as a printed wiring board base material requiring high performance. However, if the heat calendering treatment (heating and pressurizing treatment) is not performed, the nonwoven fabric cannot be given strength enough to withstand a manufacturing process such as a resin impregnation process, and a problem occurs in terms of dimensional stability and the like. In this case, it has been difficult to obtain a printed wiring board base material having both the characteristics of resin impregnation and the characteristics of mechanical performance and dimensional stability.

Although it has been considered to manufacture a printed wiring board base material by mixing reinforcing fibers with a resin, it is difficult to uniformly disperse the reinforcing fibers in the resin.
Moreover, since the orientation direction of the fibers is random, there is a limit to the reinforcement effect obtained. An object of the present invention is to provide a printed wiring board base material excellent in various properties such as homogeneity, resin impregnation property, mechanical performance, heat resistance and the like, and an efficient production method thereof. Furthermore, the present invention provides
An object of the present invention is to provide a printed wiring board and a printed wiring board which are excellent in various performances such as mechanical performance, heat resistance, moisture resistance and solder heat resistance, and have a low dielectric constant and a low dielectric loss tangent and excellent electrical characteristics.

[0007]

The present invention provides: (1) a liquid crystalline polyester fiber (component A) having a melting point of 290 ° C. or more and a molten liquid crystalline polyester binder (component B) having a melting point of 290 ° C. or more; A printed wiring board base material comprising a wet-laid product in which the component is fixed by the B component, wherein the B component has a ratio of 5 or more holes / mm ² having an opening area of 400 to 10000 μm ^{2 in} the wet-laid product. A printed wiring board base material characterized by being in the form of a film having:

The present invention provides: (2) a blending (weight ratio) of the molten liquid crystalline polyester fiber (component A) and the molten liquid crystalline polyester binder (component B) in the wet papermaking product is 20:80 to 90:10.
(3) The porosity is 40% or more and the breaking length is 0.6 km.
The printed wiring board substrate according to any one of the above (1) and (2); and (4) the above (1) having a basis weight of 20 to 100 g / m ^2.
Or the printed wiring board substrate according to any one of (3) to (3) as a preferred embodiment thereof.

Furthermore, the present invention, a wet paper stock comprising (5) a melting point 290 ° C. or more liquid crystalline polyester fiber (A component) and the melting point 290 below ° C. liquid crystalline polyester fibrous binder (B ₀ component) Papermaking, heat-treating the obtained wet papermaking under no pressure,
B ₀ component is melted open area 400～10000Myuemu ²
A film-like molten liquid crystalline polyester binder (component B) having 5 or more holes / mm ² is fixed between the components A, and the melting point of the component B is raised to 290 ° C. or higher by solid phase polymerization. A method for manufacturing a printed wiring board base material, characterized in that:

The present invention provides (6) a printed wiring board substrate according to any one of the above (1) to (4), which is impregnated or adhered with a thermosetting resin and / or a thermoplastic resin. (7) A printed wiring board using the printed wiring board according to the above (6); and (8) a printed wiring board using the printed wiring board according to the above (6). A printed wiring board formed by laminating at least a copper layer.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A printed wiring board substrate (hereinafter sometimes simply referred to as "substrate") of the present invention comprises a molten liquid crystalline polyester fiber (A component) and a molten liquid crystalline polyester binder (B component). And a liquid-crystalline polyester fiber (main fiber; component A) having excellent heat resistance is firmly fixed by a specific film binder (component B). There is a feature in the point, by using the specific binder as a component, homogeneity, heat resistance, resin impregnation,
It is a substrate with excellent performance such as mechanical performance.

The binder (B component) in the printed wiring board base material of the present invention has a specific hole as shown in FIG. 1 (photograph) in which an example of the printed wiring board base material of the present invention is photographed with an electron microscope. Is a film-like binder present in the wet papermaking constituting the substrate in the state of the formed film, whereby the resin impregnation of the substrate, homogeneity,
The performance such as mechanical performance and heat resistance becomes excellent. That is, the film area binder (component B) constituting the printed wiring board base material of the present invention has an opening area of 400 to 1
Holes of 0000 μm ² are formed at a rate of 5 or more per unit area (1 mm ² ) of the film-like binder. If the size of the holes in the film-like binder is too small, or if the number of holes is too small, the resin impregnation becomes insufficient.If the size of the holes is too large, the main fiber The component (A) is not firmly fixed, and a desired base material cannot be obtained.

From the viewpoints of resin impregnation of the printed wiring board base material and mechanical performance, a film-like binder (component B)
Has holes with an opening area of 400 to 10000 μm ²
It is preferably formed at a rate of 200 / mm ² , and more preferably at a rate of 40 to 150 / mm ² . For the same reason, the opening area of one hole in the film-like binder (component B) is as follows:
It is preferably 1000 to 5000 μm ² , and 10
More preferably, it is from 00 to 4000 μm ² . Also,
The shape of the hole is preferably a smooth shape having no corners such as a circle and an ellipse from the viewpoint of resin impregnation. The “pores formed in the film-like binder (component B)” referred to in the present specification are clearly distinguished from the voids formed between the main fibers (component A) in which substantially no binder is present. Things. The opening area of the holes in the film-like binder (B component) can be determined from an enlarged photograph (for example, about 100 times magnification) of the surface of the printed wiring board base material and the photograph. At this time, the opening area of the hole is the area of the hole formed in a portion where it can be determined that the main fiber (component A) does not exist below the hole.

From the viewpoint of the resin impregnating property and mechanical performance of the printed wiring board base material, the total area of the holes formed in the film-like binder (component B) on the surface of the base material is determined by the film-like binder (component B) ) Is preferably 5% or more, more preferably from 10 to 50%, more preferably from 10 to 20%, based on the total area (ie, the area of one surface of the base material). Is more preferable. In the printed wiring board substrate, the portion of the substrate surface where the main fiber (component A) is determined to be present on the surface portion is 5% of the surface area of the substrate.
%, More preferably in the range of 10 to 50%, even more preferably in the range of 20 to 40%. Furthermore, when the printed wiring board base material of the present invention is impregnated with the resin, the non-impregnated portion of the resin (the white portion not impregnated with the resin described in the following examples) becomes substantially zero. Is preferable.

In the printed wiring board base material of the present invention, the melting point of the component A (molten liquid crystalline polyester fiber; main fiber) and the melting point of the film-like binder (component B) are both 290 ° C. or higher. It is necessary.
When the melting points of the component A and the component B are lower than 290 ° C., the heat resistance of the base material is reduced (the dry heat shrinkage ratio is increased), and the heat resistant dimensional stability is lacking. A problem arises above. Conventionally, a binder having a low melting point is generally used as a binder in a printed wiring board base material. However, in the printed wiring board base material of the present invention, both the main component (A component) and the binder (B component) are 29.
It has a high melting point of 0 ° C or more and has excellent heat resistance.
Since the binder between the main fibers (component A) is firmly fixed by such a binder having excellent heat resistance (component B), it is excellent in various performances such as mechanical performance, dimensional stability and heat resistance. Become. From the viewpoints of heat resistance, manufacturing processability, etc., the melting points of the main fiber (A component) and the binder (B component) constituting the printed wiring board substrate are 300 to 3
It is preferably in the range of 90 ° C.,
More preferably, it is within the range of ° C.

[0016] Incidentally, liquid crystalline polyester fiber (component (A)) referred to herein, liquid crystalline polyester binder (component (B)), and liquid crystalline polyester fibrous binder prior to the B component of the (B ₀ component) The melting point is a peak temperature of a main endothermic peak observed by a differential scanning calorimeter (DSC) of the molten liquid crystalline polyester constituting the component A, the component B, or the component B ₀ according to JIS K7121. Specifically, a DSC device (for example, M
1 sample in “TA3000!
After weighing out 0 to 20 mg and sealing in an aluminum pan, nitrogen as a carrier gas is flowed at a flow rate of 100 cc / min, and the endothermic peak when the temperature is raised at 20 ° C./min can be measured and determined. 1st depending on the type of polymer
If no clear endothermic peak appears in Run,
At a heating rate of 50 minutes above the expected flow temperature, and after completely melting at that temperature for 3 minutes, 8
Cool to 50 ° C. at a rate of 0 ° C./min.
The endothermic peak may be measured at a heating rate of 0 ° C./min.

Further, the printed wiring board base material of the present invention comprises:
From the viewpoints of process stability and dimensional stability, the dry heat shrinkage after heat treatment at a temperature of 320 ° C. for 24 hours is preferably 3% or less, more preferably 0 to 2.5%, and 0%. More preferably, it is で 2%. Further, the printed wiring board base material of the present invention has a breaking length of preferably 0.6 km or more, more preferably 1 km or more, from the viewpoint of process stability, dimensional stability and the like. The upper limit of the breaking length is not limited.
km or less. Further, the printed wiring board base material of the present invention preferably has a porosity of 40% or more from the viewpoint of resin impregnation and the like, and has a porosity of 45 to 70% from the viewpoint of resin impregnation and mechanical performance. Is more preferable.

Since the printed wiring board base material is generally required to be thin, the printed wiring board base material of the present invention preferably has a thickness of 20 to 200 μm, and more preferably 25 to 100 μm. Is more preferable.
Further, the printed wiring board base material of the present invention has a basis weight of 20 to 100 g / g from the viewpoints of mechanical performance, resin impregnation, and the like.
m ² , and more preferably 25 to 50 g / m ² . Further, from the viewpoint of homogeneity, the basis weight standard deviation of the printed wiring board base material of the present invention is 0.7 to 1.0.
It is preferably 1.

Although the method for producing a printed wiring board substrate of the present invention is not particularly limited, it cannot be obtained by a conventional method of performing a heat calendering treatment at a high temperature and a high pressure. When subjected to thermal calendering at high temperature and high pressure, although the substrate surface becomes a film shape, a film shape in which holes having a predetermined opening area are formed in a predetermined number as in the printed wiring board substrate of the present invention. However, as illustrated in, for example, an electron micrograph of FIG. 2, since there is almost no hole, the resin impregnation becomes extremely low.

The preferred method for producing the printed wiring board substrate of the present invention includes a molten liquid crystalline polyester fiber (component A) having a melting point of 290 ° C. or more and a molten liquid crystalline polyester fibrous binder (B ₀ component) having a melting point of less than 290 ° C. ) to wet papermaking paper stock containing, heat-treating the resultant wet paper product in a non-pressurized, the opening area of the B ₀ component is melted 400-100
A film-like molten liquid crystalline polyester binder (component B) having 5 μm ² / mm ² pores at a ratio of 5 or more was fixed, and between the components A was fixed.
A method of raising the melting point of the component to 290 ° C. or higher can be used.

That is, in producing the printed wiring board base material of the present invention by the above method, the melting point is 290 ° C.
The above-mentioned molten liquid crystalline polyester fiber (component A) and melting point 2
It is necessary to use a less than 90 ° C. liquid crystalline polyester fibrous binder (B ₀ component). The fibrous binder (B ₀ component) may shrink during melting, but the presence of the high melting point A component (main fiber) maintains the shape of the substrate. In addition, when the B ₀ component is melted in the presence of the A component, the B ₀ component changes from a fiber form to a B component having a film form having specific pores, whereby the resin impregnation property and mechanical The printed wiring board base material of the present invention which is excellent in performance and shape retention is obtained.
When only the molten liquid crystalline polyester fiber having a melting point of less than 290 ° C. (for example, the B ₀ component) is used without using the A component, the mechanical performance and shape retention of the base material become insufficient, and conversely, When only a molten liquid crystalline polyester fiber having a melting point of 290 ° C. or more (for example, component A) is used, the binder effect becomes insufficient, and only a substrate having poor mechanical performance can be obtained.

From the viewpoint of the binder effect, the melting point of the binder fiber is preferably as low as possible. However, the mere use of the binder fiber having a low melting point lowers the heat resistance of the obtained base material, causing a problem. On the other hand, in the present invention, the binder fiber has a low melting point and exhibits excellent binder performance at the time of papermaking to obtain a wet nonwoven fabric and at the time of fixing the main fiber (component (A)). and, with the main fibers (a component) rigidly fixed to and at the same time excellent heat resistance and liquid crystalline polyester film-like binder illustrating the mechanical performance between component (B) and a fibrous binder (B ₀ component) Therefore, a printed wiring board base material excellent in various performances such as mechanical performance, form retention, heat resistance, and resin impregnation can be obtained.

The term “molten liquid crystalline” as used herein is also called “melt anisotropy”, which means that it exhibits optical liquid crystalline (anisotropic) properties in a molten phase. Whether or not a polymer has “molten liquid crystal properties” can be easily known by a known method. For example, a sample (polymer) placed on a hot stage is heated and heated under a nitrogen atmosphere, and the transmitted light is observed. The presence or absence of the liquid crystallinity can be checked by a generally adopted method such as a method of performing the method.

The printed wiring board substrate of the present invention and the molten liquid crystalline polyester fiber (A component) used for the production thereof,
Liquid crystalline polyester constituting the liquid crystalline polyester binder (component (B)) and liquid crystalline polyester fibrous binder (B ₀ component), an aromatic diol,
It is a polyester comprising a repeating structural unit such as an aromatic dicarboxylic acid or an aromatic hydroxycarboxylic acid, and is preferably a molten liquid crystalline polyester (1) to (12) represented by the following chemical formula. Of course, for the purpose of improving spinnability, the molten liquid crystalline polyester may have other copolymer units such as an isophthalic acid unit, if necessary, but from the viewpoint of fiber performance, etc. The proportion of the copolymer units is preferably small (usually 20 mol% or less).

[0025]

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[0026]

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[0027]

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Among the above-mentioned molten liquid crystalline polyesters, a structural unit represented by the chemical formula (11) consisting of a parahydroxybenzoic acid unit (X unit) and a 2-hydroxy-6-naphthoic acid unit (Y unit) ) Is preferably a molten liquid crystalline polyester having a total of 65 mol% or more, particularly 80 mol% or more.
It is particularly preferred from the viewpoint of melt spinnability and fiber performance that the liquid crystalline polyester has a proportion of 5-hydroxy-6-naphthoic acid unit of 5 to 45 mol%.

The liquid crystalline polyester constituting the component A, the component B and the component B ₀ may include polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, and polyarylate, if necessary, as long as the effects of the present invention are not impaired. ,polyamide,
One or more of other polymers such as polyphenylene sulfide, polyester ether ketone, polyarylate, and fluorine-containing resin may be contained, and inorganic materials such as titanium oxide, kaolin, silica, and barium oxide, carbon black, and dyes One or two or more of various additives such as colorants such as pigments and dyes, antioxidants, ultraviolet absorbers, light stabilizers and the like may be blended. From the viewpoint of fiber performance and the like, the content of components other than the molten liquid crystalline polyester is preferably 50% by weight or less based on the weight of the molten liquid crystalline polyester fiber, and is preferably 30% by weight or less.
It is more preferably at most 10% by weight, more preferably at most 10% by weight.

The melting point of the component A (main fiber) used in the present invention is at 290 ° C. or higher from the viewpoints of heat resistance, dimensional stability, hole forming property in a binder, processability of a binder, and the like. It is necessary to have
The temperature is preferably 390 ° C, more preferably 300 to 350 ° C. The component A may be a fiber obtained using one kind of molten liquid crystalline polyester, or a mixed spun fiber, a conjugate fiber, or a mixed fiber obtained using two or more kinds of molten liquid crystalline polyester. Good.

The component A (main fiber) having a melting point of 290 ° C. or more can be obtained by, for example, melt-spinning a molten liquid crystalline polyester to produce a spun yarn, heat-treating it, and subjecting it to solid phase polymerization. When the liquid crystalline polyester is melt-spun, the molecular weight of the polymer before and after spinning does not substantially change, but when the fiber obtained by spinning (spun yarn) is heat-treated, solid-state polymerization occurs and the degree of polymerization is reduced. As a result, the melting point (heat resistance), the mechanical performance, and the like are remarkably increased, which is preferable as the main fiber (component A) used in the present invention. The molten liquid crystalline polyester constituting the spinning yarn obtained by melt spinning is generally about 80 to 120 mer, but the main fiber (component A) is composed of about 250 to 350 mer melt liquid crystalline polyester. Is preferred.

The heat treatment conditions (solid-state polymerization conditions) for converting the spun yarn into the main fiber (component A) are not particularly limited, but may be determined by the melting point (Tm) (° C.) of the molten liquid crystalline polyester constituting the spun yarn. On the other hand, (Tm−60 ° C.) to (Tm +
(20 ° C.).
It is more preferable to perform the heat treatment (solid-state polymerization) while gradually raising the temperature from (Tm-40 ° C.) to Tm. Examples of the heating method during the heat treatment include a method using radiant heat from a heating plate or an infrared heater, a method of contacting with a heat roller, a heat plate, or the like, and an internal heating method using high frequency or the like. The heat treatment may be performed under tension or without tension.

The atmosphere during the heat treatment is not particularly limited.
The reaction can be performed under an inert gas atmosphere such as a nitrogen gas or a carbon dioxide gas, or under an active gas atmosphere containing oxygen such as air, or may be performed under reduced pressure. In addition, if moisture or moisture is present during the heat treatment, the physical properties of the fiber deteriorate. Therefore, it is preferable to use a dehumidified gas.

A more specific and suitable method for producing the main fiber (component (A)) includes, for example, the following method. For example, parahydroxybenzoic acid unit (X unit): 2-hydroxy-6-naphthoic acid unit (Y unit)
Of a liquid crystalline polyester having a molar ratio of 73:27, a melt viscosity of 430 poise, a degree of polymerization of about 100, and a melting point of about 280 ° C. is vacuum-dried at 140 ° C. for 100 hours. After being supplied and filtered through a filter layer composed of a sand layer and a metal fiber and having an average pore diameter of 5 μm, the mixture is spun from a spinneret (nozzle hole diameter 0.08 mm, 50 holes) at 320 ° C. to form a molten liquid crystalline polyester fiber (spun yarn) ) (Melting point 280 ° C.), and heat treating the fiber at 280 to 300 ° C. to perform solid-phase polymerization.
By increasing the degree of polymerization to about 300,
Fiber suitable as the main fiber (component (A)) can be obtained smoothly and efficiently.

The form of the main fiber (component (A)) may be any of filaments, cut fibers, and beaten products, and is not particularly limited. However, the formability, mechanical performance of the obtained printed wiring board base material, resin impregnation, etc. From the viewpoint, a cut fiber obtained by cutting a fiber obtained by spinning is preferable. The cut fiber preferably has a fiber diameter of 5 to 30 μm and a fiber length of 2 to 20 mm from the viewpoints of papermaking properties, paper strength, and the like. When used in the form of cut fibers, heat treatment (solid-state polymerization) for increasing the melting point may be performed at any stage before or after cutting.

The fiber strength of the main fiber (component A) is 16 g /
d or more, preferably 18 g / d or more, and more preferably 20 g / d or more. Although the upper limit of the fiber strength is not particularly limited, it is preferable that the fiber strength be 50 g / d or less from the viewpoint of production cost and the like. The elastic modulus of the main fiber (component A) is 400
g / d or more, preferably 500 to 2000 g
/ D is more preferable.

In the production of the printed wiring board substrate of the present invention, the melting point is less than 290 ° C., preferably 280 ° C. or less from the viewpoint of the binder effect and the pore-forming property of the binder together with the main fiber (component A) described above. A molten liquid crystalline polyester binder fiber (B ₀ component) is used. From the viewpoint of heat resistance of the resulting printed wiring board substrate, it is preferable to use a high melting point binder fiber (B ₀ component), the melting point of the binder fiber (B ₀ component) is too high, main fibers (A binder effect is reduced to component), moreover binder fiber (B ₀ component) film-like binder having a hole suitable for the impregnation of even melted resin (B component) becomes is hardly formed, resulting printed wiring board base The mechanical performance and the resin impregnation of the resin are reduced.
Therefore, good heat resistance, mechanical performance, and resin impregnating property [pore forming property in film-like binder (component B)]
In order to obtain a printed wiring board base material having both of the above, it is preferable to use a molten liquid crystalline polyester binder fiber (B ₀ component) having a melting point in the range of 260 to 280 ° C., and in the range of 260 to 270 ° C. It is more preferable to use When the binder fiber (B ₀ component) having the above-mentioned melting point is used, the melting point of the binder fiber (B ₀ component) is low at the time of papermaking, and an excellent binder effect is exhibited. It becomes a film-like binder having pores suitable for impregnation, which is then heat-treated and solid-phase polymerized to a melting point of 290.
By using a film-like binder (component B) at a temperature of at least 100 ° C., a printed wiring board substrate having significantly improved heat resistance and mechanical performance can be obtained.

Binder fibers having a melting point of less than 290 ° C. (B ₀
As the component), a raw yarn obtained by melt-spinning a molten liquid crystalline polyester having a melting point of less than 290 ° C., that is, a fiber that has not been subjected to a heat treatment (solid-state polymerization) for raising the melting point after melt-spinning is used. Can be.

The binder fiber (B ₀ component) must be fibrous as the name implies. binder
When the (B ₀ component) is in a powdery or granular form, the main fiber (A
Component) and a binder (B ₀ component) become difficult to obtain a wet paper product in which the binder is homogeneously dispersed, and even if the binder in the wet paper material is melted, the viscosity does not sufficiently decrease, so that it becomes difficult to become a film-like binder. Moreover, predetermined holes suitable for resin impregnation are not formed in the film-like binder,
The printed wiring board base material of the present invention cannot be obtained.

Although the fiber form of the binder fiber (B ₀ component) is not particularly limited, it is preferably a fine pulp-like material in terms of paper formability, pore forming properties, etc. Fiber point 1
It is more preferable that the pulp is a pulp having a length of about 7 μm, particularly 1 to 5 μm, and a fiber length of about 0.1 to 3 mm. The pulp-like binder fiber (B ₀ component) is fine, has a high paper-making property and a high binder effect, and is easily melt-integrated with each other to easily form a film and a predetermined hole is easily formed in the film.
It has even better effects. For the same reason as described above, binder fibers (B ₀ component) having a freeness of 600 cc or less (CFS; Canadian standard freeness value) are preferably used, and those having 0 to 550 cc are more preferably used.

Pulp-like binder fiber (B ₀ component)
Can be produced by beating and pulverizing a molten liquid crystalline polyester fiber, a film made of the molten liquid crystalline polyester or other molded product, preferably a spinning yarn of the molten liquid crystalline polyester with a refiner or the like; Manufactured from sea-island composite fibers or laminated composite fibers containing 1 as a component by removing the other components by applying a solvent, acid, or alkali treatment before or after cutting the fibers into short fibers. it can. In the present invention, a single fiber fineness of 5 is used as the binder fiber (B ₀ component).
Pulp fibers obtained by beating and pulverizing cut fibers of molten liquid crystalline polyester fibers of denier or less are more preferably used.

Further, the binder fiber (B ₀ component) contains 1
Even if it is a single fiber of molten liquid crystalline polyester,
Alternatively, it may be a mixed spun fiber, a conjugate fiber and / or a mixed fiber formed using two or more kinds of molten liquid crystalline polyester.

Further, the binder fiber (B ₀ component)
It is preferable to use a molten liquid crystalline polyester fiber having a fiber strength of 5 to 15 g / d or a fiber obtained by beating and pulverizing the fiber. Further, the elastic modulus of the binder fiber (B ₀ component) is 2
It is preferably about 00 to 600 g / d.

The method for producing the printed wiring board substrate of the present invention is not particularly limited, but it can be suitably produced, for example, by the following method. First, a paper material containing at least the main fiber (A component) and the binder fiber (B ₀ component) is wet-processed to form a paper product. Main fiber (A component) at that time:
The blending ratio (weight ratio) of the binder fiber (B ₀ component) is preferably 20:80 to 90:10 from the viewpoints of paper formability, mechanical performance of the obtained printed wiring board base material, and the like. In order to improve the pore forming property (resin impregnating property) in addition to the properties, the compounding ratio is 20:80.
More preferably, it is ６０60: 40. If the blending ratio of the binder fiber (B ₀ component) is too small, the adhesion and fixation between the main fibers (A component) become insufficient, so that the papermaking property and the paper strength are reduced and the resin has pores suitable for resin impregnation. It becomes difficult for the film-like binder to be formed in the substrate. That is, to obtain the printed wiring board substrate of the present invention,
It is necessary viscosity of the binder fiber (B ₀ component) specific pores in the film are formed by a certain number with be sufficiently reduced the binder fiber (B ₀ component) are integrated into a film form by melt Is a binder fiber (B ₀ component)
If the amount is too small, it will not become a film-like binder even if it is melted, and it will be difficult for holes to be formed. Conversely, if the proportion of the main fiber (component A) is too small, the mechanical performance and dimensional stability of the obtained printed wiring board base material become insufficient, and specific holes are not easily formed in the film-like binder. Become.

Further, the above-mentioned stock used for the production of a papermaking product includes a main fiber (A component) and a binder fiber (B ₀
Components other than component (5) may be contained, but in order not to impair the effects of the present invention, 5% of the solid content in the stock is used.
0% by weight or more, particularly 80% by weight, and more preferably 90% by weight or more of the main fiber (A component) and the binder fiber (B ₀ component)
It preferably comprises Further, the stock is preferably in the form of an aqueous dispersion (aqueous suspension) having a solid concentration of 0.01 to 1% by weight.

In the wet papermaking, the wet papermaking machine to be used is not particularly limited, and a conventionally known apparatus may be used.
Specifically, for example, a wire net wet machine, a short net wet machine, a short net inclined wet machine, a long net wet machine wire and Yankee, a multi-tube wet machine, hot air or radiant heat And a wet papermaking machine equipped with a drier. The wet-laid nonwoven fabric can be produced by drying the obtained wet-laid paper. The wet-laid non-woven fabric usually has a high porosity of 60% or more, and has good resin impregnation properties, Poor performance (normally 0.2 km or less in breaking length), and there is a problem in processability. For this reason, in the present invention, it is necessary to heat-treat the wet papermaking product after drying under non-pressure, and perform the heat treatment to obtain the binder fiber (B ₀ component).
Is melted, and the open area is 400 to 100 in the wet papermaking.
A film-like binder having 5 or more holes of 00 μm ² at a ratio of 5 / mm ² is formed, and the main fibers (component A) are fixed. By making the binder fiber (B ₀ component) into a film-like binder having the specific pores described above, a printed wiring board base material having excellent resin impregnation properties can be obtained. At this time, the film-like binder formed from the binder fiber (B ₀ component) is subjected to solid-state polymerization to have a melting point of 290.
It is necessary that the temperature be higher than or equal to ° C (that is, the component B). If the solid phase polymerization of the film binder is not performed,
The heat resistance of the printed wiring board base material becomes insufficient, and the bonding between the main fibers (component (A)) does not become strong, and the printed wiring board intended in the present invention cannot be obtained.

As described above, the heat treatment for the wet papermaking must be performed under substantially no pressure. If a heat press treatment (a heat calendering treatment) with a press, which has been widely performed conventionally, is adopted, the paper strength is reduced. However, the resin impregnating property is greatly reduced, and a target printed wiring board base material cannot be obtained. The term "under no pressure" as used in the present invention refers to a state in which a substantially large pressure is not applied to a wet papermaking product, and the heat treatment may be performed by any method in such a state. For example, there is a method in which one side or both sides of a wet papermaking is brought into contact with a heat roller to continuously heat the paper. At this time, it is necessary to reduce the linear pressure of the kneading roller on the wet papermaking product, and it is preferable to set the linear pressure to about 0 to 10 kg / cm. Of course, instead of the contact heating method using a heat roller, a convection heating method using hot air or the like, a radiant heating method using far infrared rays or the like may be adopted, and two or more of these may be used in combination. Specific heat treatment conditions may vary depending on the types of the main fiber (component A) and the binder fiber (component B ₀ ), the mixing ratio of both, and the like, but generally, the heat treatment temperature is 200 to 400 ° C, particularly 260 to 400 ° C.
The heat treatment time is preferably about 350 ° C., and the heat treatment time is preferably about 10 minutes to 48 hours, particularly about 10 to 40 hours.

The heat treatment for melting the binder fiber (B ₀ component) and the heat treatment for solid-phase polymerization may be performed in the same step or in separate steps. After the fibers (B ₀ component) are melt-bonded, it is preferable to perform a hot-air treatment to perform solid-phase polymerization. At this time, the heat treatment for melting the binder fibers (B ₀ component) [binder fiber melting point of (B ₀ component) (Tm) -10 ° C.] [the melting point of (Tm) +10
C.], at a linear velocity of 5 to 30 m / min., And the heat treatment for solid-phase polymerization is performed from [the melting point (Tm) + 10 ° C.] to [the melting point (Tm) + 70 ° C.].
[° C.], and a heat treatment time of 10 to 30 hours. By adopting the above-described heat treatment conditions, a printed wiring board base material excellent in various properties such as resin impregnation property and mechanical performance can be effectively manufactured.
From the viewpoint of processability, etc., it is preferable to heat and dry the wet papermaking product at a low temperature (for example, about 100 to 150 ° C.), and then perform the above-described heat treatment for melting the binder fiber (B ₀ component). preferable.

Further, since the printed wiring board is required to be thin, the printed wiring board base obtained by performing a heat treatment for melting the binder fiber (B ₀ component) and a heat treatment for solid phase polymerization is used. If necessary, the thickness may be further reduced by a low-temperature pressing treatment. Since the morphology of the base material is stabilized by the heat treatment for the above-mentioned melting and solid-phase polymerization, the base material can be thinned without substantially impairing the resin impregnation property of the base material even when a low-temperature press treatment is performed.
The temperature of the low-temperature press treatment is 0 to 140 ° C, particularly 0 to 100 ° C.
° C, and a linear pressure of 100 kg / cm or less,
Particularly, it is preferably 1 to 50 kg / cm.

Further, the obtained printed wiring board base material is
If necessary, a physical and / or scientific treatment may be applied to improve the adhesiveness to the resin to be impregnated therein, the wettability by the resin, and the like. Specific examples include corona discharge treatment, glow discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet irradiation treatment, physical treatment such as heat treatment in an oxygen-containing atmosphere, and chemical treatment such as sputtering. Two or more of these treatments may be used in combination. When the heat treatment for melting and / or solid-phase polymerization of the binder fiber (B ₀ component) is performed in an oxygen-containing atmosphere, the adhesiveness to the resin of the base material without additional treatment, The wettability can be significantly increased.
In particular, it is preferable to perform heat treatment in an oxygen-containing atmosphere, corona discharge treatment, or both of them, because the adhesion to the resin of the base material can be efficiently increased.

When the heat treatment is performed in the above-mentioned oxygen-containing atmosphere, the surface of the main fiber (component A) is oxidized to form polar groups such as carboxyl groups on the surface, thereby improving the adhesiveness and wettability with the resin. I do. This heat treatment is 200-400
C., particularly preferably at 300 to 400.degree. C. for 1 minute or more. The heat treatment time is preferably 30 hours or less from the viewpoint of processability. This heat treatment is performed on the binder fiber (B ₀
For the purpose of melting and / or solid-state polymerization of the component), it may be performed in the same step as the heat treatment or in a separate step. In addition, when performing the above-described corona discharge treatment, it is preferable to perform the treatment under a condition of 0.5 to 3 kW from the viewpoint of suppressing the activation effect and carbonization of the fiber.

The printed wiring board substrate of the present invention obtained as described above can be distributed and sold as it is. Further, a prepreg is manufactured by impregnating or attaching a thermosetting resin and / or a thermoplastic resin (matrix resin) to the base material, and a single layer or a plurality of prepregs are manufactured to manufacture a printed wiring board. be able to. Suitable matrix resins used for the production of prepregs include, for example, one or two or more thermosetting resins selected from phenol resins, epoxy resins, unsaturated polyester resins, cyanate resins, maleimide resins, polyimide resins, and the like. Can be Further, one or two of the above-described thermosetting resins are modified by adding polyvinyl butyral, acrylonitrile-butadiene rubber, a polyfunctional acrylate compound, or the like; Thermosetting resins (IPM-type or semi-IPM-type polymer alloys) obtained by modifying a resin, a crosslinked polyethylene-modified cyanate resin, a polyphenylene ether-modified cyanate resin, or the like with a thermoplastic resin can also be used as the matrix resin. Among them, an epoxy resin, a polyimide resin, an unsaturated polyester resin, a cyanate resin and the like are suitable as a matrix resin for a printed wiring board. Further, main fibers (A component) and / or as a binder fiber (B ₀ component) mainly composed of molten anisotropically from p- hydroxybenzoic acid unit (X unit) and 2-hydroxy-6-naphthoic acid unit (Y unit) When a fiber made of a conductive polyester is used, the adhesiveness with the fiber is excellent,
A bismaleide-triazine resin having excellent insulating properties and heat resistance is preferably used as the matrix resin.

Although the content of the matrix resin in the prepreg is not particularly limited, it is intended to suppress delamination and poor molding and to improve the mechanical performance, dimensional stability and thermal stability of the printed wiring board. Preferably, 30 to 95% by weight, particularly 40 to 80% by weight, of the total weight of the prepreg is used as the matrix resin.

The method of impregnating or attaching the resin to the printed wiring board substrate is not particularly limited, and a conventionally known method may be used. For example, an impregnation method, a coating method, a transfer method, or the like may be employed. Specifically, a method of impregnating a substrate with a varnish prepared by dissolving a matrix resin in a solvent and drying the substrate, impregnating the substrate with a liquid matrix resin in a room temperature state or a heated state prepared without using a solvent. A method, a method of fixing a powdery matrix resin to a substrate, a method of forming a matrix resin layer on a film or sheet having releasability, and then transferring the layer to the substrate can be adopted.
Since the printed wiring board base material of the present invention is excellent in resin impregnating properties, the entire printed wiring board base material can be impregnated with resin, and excellent effects can be obtained. When drying the matrix resin impregnated or adhered to the base material, it is preferable to dry the matrix resin in a non-contact state using a vertical dryer.

A printed wiring board may be manufactured using at least one prepreg obtained by such a method.
Specifically, a printed wiring board composed of a single layer of the prepreg, a printed wiring board formed by laminating two or more prepregs, one or more prepregs and other materials (for example, glass cloth, glass nonwoven fabric, other fibers A printed wiring board formed by laminating a cloth, a porous substrate, a plastic sheet, a plastic film, a plastic plate, etc.). In order to sufficiently achieve the effects of the present invention, it is preferable that the printed wiring board is composed of only the prepreg obtained by impregnating the printed wiring board base material of the present invention with a resin. It is more preferable to manufacture a printed wiring board by laminating about 2 to 5 prepregs in order to improve electrical characteristics, workability and the like.

A printed wiring board is obtained by laminating a metal layer on such a printed wiring board. The metal layer may be a single layer or a plurality of layers. Examples of the metal layer include a metal foil, a metal sheet, a metal plate, and a metal net, and in some cases, two or more of these may be used in combination. Further, the metal layer may be subjected to a surface treatment or the like. As a metal constituting the metal layer, copper, iron, aluminum, or the like is preferable, and among them, copper is preferably used. Of course, two or more of the above-mentioned metals can be used in combination. The thickness of the metal layer is preferably about 10 to 50 μm from the viewpoint of handleability, electric characteristics and the like. The bonding between the metal layer and the printed wiring board may be performed using an adhesive in some cases.

The method for manufacturing the printed wiring board is not particularly limited, and may be manufactured in the same manner as a conventionally known method. For example, one or two or more prepregs in which the printed wiring board base material of the present invention is impregnated with a resin are used, and if necessary, other materials are used in combination. By curing and / or solidifying the matrix resin and bonding between layers, a desired printed wiring board can be manufactured. Appropriate conditions for the heating temperature, pressure and the like at that time may be adopted according to the type of the matrix resin, the type of the material to be laminated, the number of layers and the like. Of course, a plurality of prepregs may be laminated and integrated beforehand, and then the metal layers may be laminated and integrated.

The thickness of the printed wiring board is preferably about 0.2 to 0.8 mm from the viewpoint of handleability and the like, and the specific gravity is 1.5 or less, particularly 0.8 to 1.4. Is preferred. Furthermore, from the viewpoint of electrical characteristics, the dielectric constant of the printed wiring board is preferably 3.3 or less, particularly 2.0 to 3.2, and the dielectric loss tangent is 0.0098 or less, particularly 0.0085 to 0. .0095 is preferred.

[0059]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples. The methods for measuring or evaluating various physical properties in Examples and Comparative Examples are shown below.

[Melt Viscosity (Poise) of Molten Liquid Crystalline Polyester]
The measurement was performed using a Capillograph (“Capillograph 1B” manufactured by Toyo Seiki Co., Ltd.) under the conditions of ° C. and a shear rate r = 1000 sec ⁻¹ .

[Melting Point (° C.)] As described above, 10 to 20 mg of a sample is weighed and sealed in an aluminum pan in a DSC device (for example, “TA3000” manufactured by Mettler), and then 100 cc / nitrogen is used as a carrier gas. The endothermic peak was measured by flowing at a flow rate of 20 ° C./min and heating at a rate of 20 ° C./min.If no clear endothermic peak appears in the first run, it is expected at a rate of 50 ° C./min. Raise the temperature to 50 ° C higher than the flow temperature, and
After melting completely for 50 minutes, the temperature is reduced to 50 ° C. at a rate of 80 ° C./min.
Then, the endothermic peak was measured at a heating rate of 20 ° C./min.

[Fiber strength (g / d)] JIS L10
According to No.13, a tensile strength tester (Shimadzu Corporation "Strong tensile strength tester DCS-100 type") was used, and the sample was stretched under the conditions of a sample length of 20 cm, an initial load of 0.1 g / d, and a tensile speed of 10 cm / min. A breaking test was performed, and the strength of the fiber was determined from the obtained stress-strain curve. The average value of the measured values of five or more points was adopted.

[Elastic modulus of fiber (g / d)] JIS L
According to 1013, a sample length of 200 m was measured using a high elongation tester (“Digital Strength Tester DCS-100” manufactured by Shimadzu Corporation).
m, an initial load of 0.1 g / d and a tensile speed of 10 cm / min were subjected to a tensile rupture test. From the obtained stress-strain curve, the modulus of elasticity of the fiber = (w / D) / (ΔL / L) Calculated. In addition, w represents the load (g) when ΔL is elongated, D is the denier of the fiber (d), ΔL is the length (mm) elongated by the load, and L represents the original length of the fiber (200 mm). ]

[Fiber diameter (μm)]
A photograph of the side surface of the fiber magnified 00 times was taken, and the fiber diameter was measured at any 10 points, and the arithmetic average was defined as the fiber diameter.

[Number of holes (number / mm ² ) and average opening area (μm ² ) of holes in the film-like binder in the printed wiring board base material] An enlarged photograph of the surface of the printed wiring board base material (100 × magnification) Degree, photography area 0.2m
m ² or more), and an opening area of 400 to 10,000 μm formed in the film-like binder (component B) on the photograph.
The number of ^second holes was measured to determine the number of film-like binder 1 mm ² per hole. Further, the opening area is 400 to 100
The average opening area was determined by arithmetically averaging the opening areas of the holes in the range of 00 μm ² . The pores formed in the film-like binder (component B) here are clearly distinguished from the voids formed between the main fibers (component A) in which substantially no binder is present, The opening area of the hole is
The area was defined as the area where it could be determined that the main fiber (component A) was not present in the layer below the hole.

[Main Fiber in Printed Wiring Board Substrate
Area ratio (%) of (A component)] An enlarged photograph of the surface of the printed wiring board base material (magnification: about 100 times) is taken, and a portion of the surface layer of the base material where the main fiber (A component) is recognized as present is recognized. The area ratio (the ratio of the total area of the site to the surface area of the base material) was determined and defined as the area ratio of the main fiber (component A).

[Ratio of Hole Formation in Printed Wiring Board Substrate (%)] An enlarged photograph of the surface of the printed wiring board base material (approximately 100 times magnification) was obtained, and the opening area occupied by the film binder (component B) was 400 to 10000 μm. The ratio of the total area of the holes of No. ² (the ratio of the total area of the holes to the surface area of the substrate) was defined as the hole formation ratio.

[The basis weight of the printed wiring board base material (g /
m ² ) and thickness (μm)] The basis weight of the printed wiring board base material conforms to JIS P8124, and the thickness is JIS.
It was measured according to P8118.

[Standard deviation of basis weight of printed wiring board base material] A square (50 cm × 50 cm) test piece was cut out at a position 20 cm or more inside from the end of the printed wiring board base material, and a small 5 cm × 5 cm piece was cut out. Cut into squares,
The basis weight of 100 small squares obtained thereby was measured, and the standard deviation was determined. The smaller the standard deviation, the more uniform the thickness of the substrate and the more uniformly the fibers are dispersed.

[Void ratio of printed wiring board base material (%)]
The basis weight W (g / m ² ) and thickness D (mm) of the sample (printed wiring board base material) were measured according to JIS P8124 and JIS P8118, and the porosity (%) = [1-
{W / (D × 10 ³ × d)}] × 100. Here, d is the density (g / cm ³ ) of the polymer constituting the printed wiring board base material.

[The tear length of the printed wiring board base material (k
m)] A test piece of longitude × wet = 200 mm × 150 mm was cut out from the printed wiring board base material, and was subjected to JIS P8113-
Measure the meridian and latitudinal strength according to 1976,
The value was divided by the basis weight to calculate the breaking length, and the arithmetic average thereof was defined as the breaking length. The breaking length is an index mainly indicating the tensile strength of the printed wiring board. In general, when the breaking length is 0.6 km or more, the processability such as the resin impregnation process and the dimensional stability are improved.

[Resin Impregnating Property of Printed Wiring Board Substrate] Matrix resin liquid (varnish) produced in Reference Example 3 below
A substrate obtained by adding 0.5% by weight of cyaning blue powder to a substrate is impregnated into a printed wiring board substrate, heated at 150 ° C. for 6 minutes and dried to form a prepreg, and a copper foil having a thickness of 18 μm is laminated thereon. Temperature 180 ° C, Surface pressure 20kg / c
It was hot pressed under the conditions of m ² and 90 minutes. A test piece of 10 cm × 10 cm in length × width = 10 cm × 10 cm was cut out from the obtained copper-clad laminate, etched at room temperature for 10 minutes using a ferric chloride solution, and the state of the surface was observed with a microscope.
The number of white spots (non-impregnated portions of the resin) having a diameter of 0.5 mm or more was counted. The higher the number of white spots, the lower the resin impregnating property.If the resin impregnating property is low and inferior, passing through the soldering step after absorbing water in the etching step causes destruction of the surface, etc. Water absorption occurs and causes troubles such as dielectric breakdown.

[Dry Heat Shrinkage Rate (Heat Resistance) (%) of Printed Wiring Board Substrate] A test piece (about 10 cm × 10 cm) collected from the printed wiring board base was placed in an oven at 280 ° C.
At 24 hours and at 24 hours at 320 ° C. to evaluate the heat resistance. In addition, the area shrinkage rate was obtained by calculating the area of the test piece before the heat treatment as A (100 c
m ² ) and the area of the test piece after the heat treatment is B, which is a value calculated by area shrinkage (%) = {(AB) / A} × 100.

[Resin Adhesion to Printed Wiring Board Substrate]
The matrix resin liquid (varnish) prepared in Reference Example 3 below was coated on the surface of the printed wiring board base material at 65 ± 2% by weight /
(Base weight + resin weight) is applied and impregnated, and the resulting prepreg is visually observed. If the matrix resin is thinly and uniformly impregnated on the base material, Good (◎), when the matrix resin is thinly impregnated in the base material but there is a repelling part, almost good (○), and when the matrix resin is thickly attached to the base material surface and the inside is not impregnated. It was evaluated as poor (x).

[Dielectric constant and dielectric loss tangent of printed wiring board] The dielectric constant and dielectric loss tangent of the printed wiring board were measured at a temperature of 25 ° C ± 2 ° C by a modified bridge method according to JIS C6481.

[Specific Gravity of Printed Wiring Board] The printed wiring board was etched to completely remove the copper foil, sufficiently washed with water, dried at 120 ° C. for 2 hours, and then formed into a square (25 mm × 25 mm). Cut out the test piece and use JI
The specific gravity was measured according to the SK7112 method.

[Solder Heat Resistance of Printed Wiring Board] A square test piece (50 mm × 50 mm) was cut out from the printed wiring board, and 3/4 of the copper foil was removed by an etching method. Dried at 120 ° C. for 1 hour. It is put in boiling water, boiled for 2, 4, 6 or 8 hours and then taken out in air at 260 ° C. for 1 hour.
Heated for 80 seconds. After cooling to room temperature, the copper foil surface, the copper foil-removed surface, the end surface, and the printed wiring board surface are visually inspected for swelling and / or peeling, and any swelling and / or peeling occurs on any surface. The case where no swelling and / or peeling occurred at one place was evaluated as poor (x). Also,
A test piece not boiled in boiling water (boiling time: 0 hours) was also heated in air at 260 ° C. for 180 seconds, and similarly, the presence or absence of swelling and / or peeling was observed. A printed wiring board with low solder heat resistance has excellent electrical properties at first, but after a long period of time, absorbs moisture and the like, and the electrical properties deteriorate.

Reference Example 1 [Production of Molten Liquid Crystalline Polyester Fiber (Main Fiber; Component A)] (1) As the molten liquid crystalline polyester, the above formula (1) was used.
A molten liquid crystalline polyester having a ratio (molar ratio) of parahydroxybenzoic acid unit (structural unit X): 2-hydroxy-6-naphthoic acid unit (structural unit Y) of 73:27 shown in 1) (melt viscosity 430) (Poise, degree of polymerization: 100, melting point: 280 ° C.) was vacuum-dried at 140 ° C. for 100 hours, fed to a vented single screw extruder, and filtered through a filter layer composed of a sand layer and metal fibers having an average pore size of 5 μm. Spinneret (nozzle hole diameter 0.08mm, 50 holes)
At 320 ° C. from a molten liquid crystalline polyester spun yarn having an average fiber diameter of 17 μm (melting point: 280 ° C., strength: 13
g / d, elastic modulus 520 g / d). (2) The molten liquid crystalline polyester spun yarn obtained in the above (1) is heat-treated at 280 to 300 ° C. for 17 hours to carry out solid phase polymerization to raise the melting point to 320 ° C.
mm, strength 25 g / d and elastic modulus 550
g / d molten liquid crystalline polyester short fiber (main fiber; A
Component) (melting point 320 ° C.).

[0079] "Reference Example 2" Production of liquid crystalline polyester fibrous binder (B ₀ component)] (1) the above formula as a molten liquid crystalline polyester (1
A molten liquid crystalline polyester having a ratio (molar ratio) of parahydroxybenzoic acid unit (structural unit X): 2-hydroxy-6-naphthoic acid unit (structural unit Y) of 73:27 shown in 1) (melt viscosity 430) (Poise, degree of polymerization: 100, melting point: 280 ° C.) was vacuum-dried at 140 ° C. for 100 hours, fed to a vented single screw extruder, and filtered through a filter layer composed of a sand layer and metal fibers having an average pore size of 5 μm. Spinneret (nozzle hole diameter 0.08mm, 50 holes)
At 320 ° C. from a molten liquid crystalline polyester spun yarn having an average fiber diameter of 17 μm (melting point: 280 ° C., strength: 13
g / d, elastic modulus 520 g / d). (2) The melt-anisotropic polyester spun yarn obtained in the above (1) is cut into a fiber length of 5 mm, then dispersed in water to form an aqueous suspension, beaten by a general-purpose disc refiner, and fiberized. Molten liquid crystalline polyester fibrous binder having a diameter of about 1 to 5 μm (B ₀ component) (CSF500c
c) (melting point 280 ° C.).

Reference Example 3 [Production of Matrix Resin Liquid (Varnish)] 2,2-bis (4-cyanatophenyl) propane 900
Parts by weight and bis (4-maleidophenyl) methane at a temperature of 150 ° C. for 130 minutes, and then the resulting product is dissolved in 60 parts by weight of a mixed solvent of methyl ethyl ketone and N, N-dimethylformamide. Dissolved. 50 parts by weight of the obtained solution was mixed with bisphenol A epoxy resin (“Epicoat 100” manufactured by Yuka Shell Epoxy Co., Ltd.).
1 ", epoxy equivalent = 450-500) 70 parts by weight and zinc octylate 0.02 part by weight were dissolved to prepare a matrix resin liquid (varnish).

Examples 1 to 3 (1) The molten liquid crystalline polyester fiber (component A) produced in Reference Example 1 and the molten liquid crystalline polyester fibrous binder (B ₀ component) produced in Reference Example 2 were used. A 0.1% aqueous slurry (paper stock) was prepared by using the ratio (weight ratio) shown in Table 1 below, and the paper stock was wet-processed with a circular net Yankee test paper making machine at 105 ° C. Dry with a basis weight of about 5
A wet papermaking (raw material) having a thickness of 0 g / m ² and a thickness of about 120 µm was produced. (2) A heat treatment is performed by bringing the raw material obtained in (1) above into contact with the surface of a steel heat roller (temperature: 280 ° C., linear velocity: 10 m / min) under no pressure (pressure 0 kg / cm). ,
Then, it was left in a hot air drying furnace at 300 ° C. for 24 hours to perform heat treatment in air. Further, the substrate was continuously passed through a corona discharge treatment device (output: 1 KW / m ² ) at a speed of 10 m / min to perform a corona discharge treatment to produce a printed wiring board base material. When the physical properties of the printed wiring board base material thus obtained were measured or evaluated by the above-described methods, the results were as shown in Table 1 below.

(3) The printed wiring board base material obtained in (2) was impregnated with the matrix resin solution (varnish) prepared in Reference Example 3 and dried at 150 ° C. to obtain a resin content of 66 to 68 wt. % Prepreg was produced. Four prepregs were stacked, and a copper foil having a thickness of 35 μm was stacked on both surfaces thereof. The laminate was placed between stainless steel mirror surfaces and pressurized and heated under the conditions of a pressure of 40 kg / cm ² and a temperature of 200 ° C. for 2 hours to perform lamination molding to obtain a thickness of 0.40 mm.
A printed wiring board of ０．４0.45 mm was manufactured. The physical properties of the printed wiring board thus obtained were measured or evaluated by the methods described above, and the results were as shown in Table 1 below.

<< Embodiment 4 >> In Embodiment 2 (2),
After heat treatment in a 300 ° C. hot air drying furnace, a low-temperature press treatment is performed with a steel hot roller (temperature: 80 ° C., linear speed: 10 m / min) at a linear pressure of 30 kg / cm, and the printed wiring board substrate The printed wiring board base material and the printed wiring board were manufactured in the same manner as in Example 2 except that the thickness of the printed wiring board was reduced, and then a corona discharge treatment was performed. Table 1 shows the results.

Example 5 A printed wiring board substrate and a printed wiring board were manufactured in the same manner as in Example 2 except that the corona discharge treatment was not performed. Table 1 shows the results.

[0085] "Comparative Example 1" liquid crystalline polyester fiber (A component) and liquid crystalline polyester fibrous binder (B ₀ component) and as shown in Table 1 95: Example except for using a weight ratio of 5 A printed wiring board substrate and a printed wiring board were produced in the same manner as in Example 1. The results are shown in Table 2 below.

Comparative Example 2 A raw fabric was produced using the molten liquid crystalline polyester fibrous binder (B ₀ component) alone, and the raw fabric was heated at a temperature of 250 ° C. by a steel heat roller (linear speed: 10 m / min). A printed wiring board base material and a printed wiring board were manufactured in the same manner as in Example 1 except that the surface of was subjected to a heat treatment while being brought into contact with the surface under no pressure (pressure 0 kg / cm). Table 2 shows the results.

Comparative Example 3 Example 2 was repeated except that the heat treatment in the hot air drying furnace was not performed in (2) of Example 2.
A printed wiring board base material and a printed wiring board were manufactured in the same manner as in [Example 3]. That is, in Comparative Example 3, solid-state polymerization of a film-like binder formed by melting a molten liquid crystalline polyester fibrous binder (B ₀ component) was carried out. The melting point of the film-form binder remains at 280 ° C.]. The results are shown in Table 2 below.

<< Comparative Example 4 >> The conditions for heat treatment with a steel heat roller were as follows: roller surface temperature: 280 ° C .;
cm and a heat treatment in a hot-air drying furnace was performed in a nitrogen gas atmosphere, and a printed wiring board substrate and a printed wiring board were produced in the same manner as in Example 2.
Table 2 shows the results.

Comparative Example 5 (1) The same process as in (1) of Reference Example 1 was carried out to obtain a molten liquid crystalline polyester spun yarn having an average fiber diameter of 17 μm (melting point: 2
(80 ° C.), and the raw yarn was heat-treated at 280 to 300 ° C. for 17 hours to perform solid phase polymerization to produce a molten liquid crystalline polyester fiber (melting point: 320 ° C.). (2) After the molten liquid crystalline polyester fiber (melting point: 320 ° C.) obtained in the above (1) is bundled into a denier of about 1,000,000, it is mechanically crimped at 80 ° C., and cut to obtain a fiber length of 51 mm. A crimped fiber having an average fiber diameter of 17 μm and a number of crimps of 12 times / inch was produced, and a fiber web was produced by using the crimped fiber by a card method. At this time, the orientation of the fibers in the web was such that the weight ratio of the fibers arranged in the length direction of the web to the fibers intersecting the length direction was 1: 4. (3) The web obtained in the above (2) was placed on an 80-mesh support, and its front side was subjected to hydroentanglement treatment (spunlace treatment) (water injection nozzle diameter 0.13 mm, nozzle pitch 0.6 mm, An angle of 90 ° with respect to the web and a water jet pressure of 80 kg / cm ² ) were applied, and the backside of the web was similarly subjected to the hydroentanglement treatment. (4) The raw fabric obtained in the above (3) is heated and pressed under the conditions of a linear pressure of 80 kg / cm and a linear speed of 10 m / min using a steel heat roller at a temperature of 280 ° C. Thereafter, the same steps as in Example 1 were performed to manufacture a printed wiring board base material and a printed wiring board. The results are shown in Table 3 below.
Shown in In addition, the printed wiring board base material obtained in Comparative Example 5 had a low tensile modulus and caused a large elongation, and was inferior in process passability.

Comparative Example 6 (1) The same process as in (1) of Reference Example 1 was carried out to obtain a molten liquid crystalline polyester spun yarn having an average fiber diameter of 17 μm (melting point: 2
(80 ° C.), and the raw yarn was heat-treated at 280 to 300 ° C. for 17 hours to perform solid phase polymerization to produce a molten liquid crystalline polyester fiber (melting point: 320 ° C.). (2) The molten liquid crystalline polyester fiber (melting point: 320 ° C.) obtained in the above (1) and the molten liquid crystalline polyester spun yarn (melting point: 280 ° C.) obtained by performing the same steps as in (1) of Reference Example 1 ) At a weight ratio of 90:10 to form a 1,000,000 denier bundle, mechanically crimped at 80 ° C., and cut to obtain a fiber length of 51 mm, an average fiber diameter of 17 μm, and a number of crimps of 12 times / inch. Was manufactured, and a fiber web was manufactured by a card method. At this time, the orientation of the fibers in the web was such that the weight ratio of the fibers arranged in the length direction of the web to the fibers intersecting the length direction was 1: 4. (3) Comparative Example 5 using the web obtained in (2) above
By performing the same steps as (3) and (4), a printed wiring board substrate and a printed wiring board were manufactured. The results are shown in Table 3 below. Note that the printed wiring board base material obtained in Comparative Example 6 did not have a dense structure like a wet-laid product, so that the fibrous binder (molten liquid crystalline polyester fiber having a melting point of 280 ° C.) was melted. The main fiber (melting point 320 ° C
However, the contact portion between the molten liquid crystalline polyester fiber and the fibrous binder was bonded, but the binder did not form a film and was poor in homogeneity.

Comparative Example 7 An aramid fiber ("Kevlar 49" manufactured by DuPont, average fiber diameter 13 μm, fiber length 5 mm) was used in place of the molten liquid crystalline polyester fiber (main fiber: component A). Aramid pulp [“Nomex pulp” manufactured by DuPont, freeness (CSF) = instead of polyester fibrous binder (B ₀ component)
A printed wiring board base material and a printed wiring board were manufactured in the same manner as in Example 1 except that 200 cc) was used. Table 3 shows the results.

[0092]

[Table 1]

[0093]

[Table 2]

[0094]

[Table 3]

As is clear from the results of Tables 1 to 3, the printed wiring board base materials of Examples 1 to 5 of the present invention
It has excellent resin impregnation, resin adhesion and homogeneity, low dry heat shrinkage and excellent heat resistance, and it has a large breaking length and sufficient strength. It was excellent in the following properties. Example 1
The printed wiring board obtained by using the printed wiring board base material of the present invention has low dielectric constant, low specific gravity, homogeneity,
It was also excellent in heat resistance and solder heat resistance. Especially,
Those subjected to the corona discharge treatment (Examples 1 to 4) had high adhesion of the matrix resin and were excellent in solder heat resistance.

On the other hand, even when the molten liquid crystalline polyester fiber (main fiber: component A) and the molten liquid crystalline polyester fibrous binder (component B ₀ ) were used, in the case of Comparative Example 1 where the blending ratio of the component B ₀ was small. In (2), since the binder did not form a film, the adhesion between the main fibers (component (A)) was not strengthened, and the strength (break length) of the printed wiring board substrate was low. In the case of Comparative Example 2 in which only the fibrous binder (B ₀ component) was used without blending the main fiber (Component A), the B ₀ component was melted into a film, but the specific No specific number of holes having an open area was formed, and the binder was melted and shrunk during papermaking, and the shape could not be maintained. The obtained printed wiring board base material was poor in resin impregnation.

Further, in the case of Comparative Example 3, a predetermined number of holes having a predetermined opening area specified in the present invention were formed in the wet papermaking product by melting the molten liquid crystalline polyester fibrous binder (B ₀ component). Is formed, but the solid state polymerization of the film binder is not performed, so that the melting point of the film binder is 29.
The temperature was lower than 0 ° C., so that the resulting printed wiring board base material had a large dry heat shrinkage ratio, was inferior in heat resistance, and had a small breaking length and did not have sufficient strength. In addition, the printed wiring board obtained in Comparative Example 3 had good electrical properties at first, but had low solder heat resistance and could not maintain good electrical properties for a long period of time. Comparative Example 4 in which a heat press treatment under pressure was performed instead of a heat treatment under no pressure
In, the desired holes are not formed in the printed wiring board base material and the resin impregnating property is low, and although the initial electric properties are good, the solder heat resistance is low and the good electric properties can be maintained for a long time It was not something.

In Comparative Example 5, a nonwoven fabric entangled by the hydroentanglement method (spunlace method) using the molten liquid crystalline polyester fiber (component A) alone without using wet papermaking is used as the raw material. The printed wiring board base material obtained in Comparative Example 5 had a large standard deviation value of the basis weight and markedly uneven thickness,
The properties in each part were non-uniform, and the resin impregnating property was poor, and the electrical characteristics of the obtained printed wiring board were poor. In addition, as described above, the printed wiring board base material has a low tensile modulus, so that a large elongation occurs, and there is also a problem in terms of processability. Then, in Comparative Example 6, although is a combination of liquid crystalline polyester fiber (A component) and liquid crystalline polyester fibrous binder (B ₀ component), the hydroentanglement method regardless of the wet papermaking (spunlace )
Since the nonwoven fabric entangled in the above was used as a raw material, the printed wiring board base material obtained in Comparative Example 6 also had a large standard deviation value of the basis weight and markedly uneven thickness, and the characteristics in each part were non-uniform, Moreover, the resin impregnating property was inferior, and the electrical characteristics of the obtained printed wiring board were inferior. In addition, as described above, since it does not have a dense structure like a wet papermaking (wet nonwoven fabric), the molten liquid crystalline polyester fiber (component A) and the molten liquid crystalline polyester fibrous binder (B ₀
Although the contact portion of the component (A) was bonded, the binder did not form a film and was poor in homogeneity.

In Comparative Example 7 using aramid fiber and aramid pulp, the heat resistance of the resulting printed wiring board after forced humidification was inferior due to the high moisture absorption of the fiber and pulp. In addition, the dielectric loss tangent was high and the electrical characteristics were poor.

[0100]

The printed wiring board base material of the present invention is excellent in various performances such as dimensional stability, mechanical performance, heat resistance, resin impregnation property and homogeneity, and is a process for producing prepregs and printed wiring boards. Excellent passability and handleability. By using the printed wiring board substrate of the present invention having the above-described excellent various properties, dimensional stability, moisture resistance,
A printed wiring board and a printed wiring board which are excellent in heat resistance, homogeneity, solder heat resistance, low in specific gravity and light in weight, and low in dielectric constant and dielectric loss tangent and excellent in electric characteristics can be obtained. And, according to the manufacturing method of the present invention, the printed wiring board base material having the above-described excellent various performances can be manufactured extremely smoothly and reliably.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing a surface state of an example of a printed wiring board base material of the present invention.

FIG. 2 is an electron micrograph showing a state of a surface of a printed wiring board base material obtained by performing a heat calender treatment accompanied by pressurization during production of a raw material.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // C08J 5/24 C08J 5/24 H05K 1/03 610 H05K 1/03 610T 3/46 3/46 T B29K 105: 06 ( 72) Inventor Kenji Seimen 1-12-39 Umeda, Kita-ku, Osaka City, Osaka Prefecture Inside Kuraray Co., Ltd.

Claims (8)

[Claims] 1. A wet papermaking machine comprising a molten liquid crystalline polyester fiber (component A) having a melting point of 290 ° C. or higher and a molten liquid crystalline polyester binder (component B) having a melting point of 290 ° C. or higher, wherein the component A is fixed by the component B. A printed wiring board base material comprising a material, wherein the B component has five or more holes having an opening area of 400 to 10,000 μm ^{2 in} the wet papermaking product.
A printed wiring board base material having a film shape having a ratio of mm ² . 2. The compounding ratio (weight ratio) of the molten liquid crystalline polyester fiber (component A) and the molten liquid crystalline polyester binder (component B) in the wet papermaking product is 20: 80-9.
The printed wiring board substrate according to claim 1, wherein the ratio is 0:10. 3. A porosity of 40% or more and a breaking length of 0.
The printed wiring board base according to claim 1, wherein the base is at least 6 km. 4. The printed wiring board substrate according to claim 1, wherein the basis weight is 20 to 100 g / m ² . 5. The stock containing the melting point 290 ° C. or more liquid crystalline polyester fiber (A component) and the melting point 290 below ° C. liquid crystalline polyester fibrous binder (B ₀ component) to wet papermaking, resulting wet The paper is heat-treated under non-pressurization to melt the B ₀ component and open area 400 to 1000
A film-like molten liquid crystalline polyester binder (B component) having 5 μm ² or more pores at a rate of 5 μm ² / mm ² is used, and the A component is fixed. Further, the melting point of the B component is 290 ° C. or more by solid phase polymerization. A method for manufacturing a printed wiring board base material, comprising: 6. The printed wiring board substrate according to claim 1, wherein at least one prepreg obtained by impregnating or adhering a thermosetting resin and / or a thermoplastic resin is used. Printed wiring board. 7. A printed wiring board using the printed wiring board according to claim 6. 8. A printed wiring board obtained by laminating at least the printed wiring board according to claim 6 and a copper layer.