JP2000244082A - Printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance various performances including the mechanical performance and electrical characteristics employing a sheath type composite fibers comprising a core component of A polymer, and a sheath component comprising a sea component of B polymer and an island component of C polymer. SOLUTION: A plastic polymer, e.g. polyethylene terephthalate, may be added to a fused liquid crystal polyester being employed as A polymer. B polymer is a bendable themoplastic polymer including polyolefin preferably having fiber forming capability. Anti-fibrilation performance and mechanical performance are enhanced significantly by employing a sea island structure comprising the bendable themoplastic polymer and the fused liquid crystal polyester as a sheath component. A fused liquid crystal polyester similar to the A polymer may be employed as a C polymer. According to the arrangement, a basic material excellent in the mechanical performance and dimensional stability is produced and a printed wiring board excellent in uniformity and electrical characteristics is obtained while suppressing occurrence of resin free part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printed wiring board and a constituent material of the printed wiring board.

[0002]

2. Description of the Related Art Glass fiber cloth has been used as a base material of a printed wiring board for a long time. However, glass fiber cloth has a drawback that it is heavy, has low handleability, and has a high dielectric constant. In recent years, the use of liquid crystal aramid fiber fabrics has been studied. However, aramid fibers have a problem of low abrasion resistance, and have a high hygroscopicity. It was inappropriate.

On the other hand, it has been proposed to use a molten liquid crystalline polyester fiber having a low specific gravity, a high strength and a high elastic modulus, a low dielectric constant and a low moisture absorption as a base material of a printed wiring board. For example, Japanese Patent Application Laid-Open No. 62-36892 discloses a printed wiring board based on a woven fabric made of a molten liquid crystalline polyester fiber. Not only is it inferior in properties, it is difficult to industrially manufacture a woven fabric, but also the resulting fabric has insufficient mechanical performance, homogeneity, and the like. A printed wiring board is required not only to have excellent mechanical performance and dimensional stability but also to be homogeneous in terms of electrical characteristics. However, when fibrils are generated on the surface, the adhesion to the matrix resin is improved, but a portion (defect) where the resin does not exist is apt to be generated, so that homogeneity is impaired, and good results are obtained particularly in terms of electrical characteristics. I can't.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printed wiring board which is excellent in various performances such as mechanical performance and electrical characteristics, and a material constituting the wiring board.

[0005]

According to the present invention, there are provided (1) a core component comprising a molten liquid crystalline polyester (A polymer) and a sheath component comprising a flexible thermoplastic polymer (B polymer) as a sea component and a molten liquid crystalline polyester. A printed wiring board using a core-sheath composite fiber composed of a sea-island component having polyester (C polymer) as an island component. (2) A core component is a molten liquid crystalline polyester (A polymer), and a sheath component is bent. Thermoplastic polymer
A printed wiring board using a woven fabric containing a core-in-sheath composite fiber composed of a sea-island component having (B polymer) as a sea component and a molten liquid crystalline polyester (C polymer) as an island component; (3) core component Is a core composed of a molten liquid crystalline polyester (A polymer), a sheath component composed of a flexible thermoplastic polymer (B polymer) as a sea component and a molten liquid crystalline polyester (C polymer) as an island component. A printed wiring board using a prepreg and a conductive film obtained by impregnating a woven fabric containing a sheath type composite fiber with a resin, (4) a core component is a molten liquid crystalline polyester (A polymer), and a sheath component is a flexible thermoplastic polymer -(B polymer) penetrates both sides of a woven fabric containing a core-sheath composite fiber composed of a sea component and a sea-island component having a molten liquid crystalline polyester (C polymer) as an island component. A printed wiring board to which a conductive material is applied and a circuit pattern is formed by the conductive material; (5) the fabric is a mesh-like fabric having a density of 200 to 500 mesh and an opening ratio of 30% or more; The printed wiring board according to any one of (4),
(6) The printed wiring board according to any one of (1) to (5), wherein a gentle undulation is formed on the surface of the core-sheath composite fiber.
(7) The core component is a molten liquid crystalline polyester (A polymer) and the sheath component is a flexible thermoplastic polymer (B polymer).
The present invention relates to a printed wiring board forming material comprising a sea-island component having a sea component and a molten liquid crystalline polyester (C polymer) as an island component, and comprising a woven fabric containing a core-sheath composite fiber.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystalline polyester (A polymer) as a core component, a flexible thermoplastic polymer (B polymer) as a sheath component and a sea component and a molten liquid crystalline polyester (C polymer) as a sheath component. A printed wiring board excellent in various performances is obtained by using a core-sheath type composite fiber composed of a sea-island component having-) as an island component. The core-sheath type conjugate fiber used in the present invention has excellent fibril resistance despite its excellent mechanical performance, so that it becomes a substrate having excellent mechanical performance and dimensional stability, A printed wiring board excellent in homogeneity and electrical characteristics can be obtained with less occurrence of portions (defects) in which no is present. In particular, when a gentle undulation is formed on the surface of the fiber, it is possible to enhance the adhesiveness with a resin or the like without impairing the fiber performance and homogeneity,
A more remarkable effect is obtained.

The term “molten liquid crystalline (anisotropic)” used in the present invention means:
To exhibit optical liquid crystallinity (anisotropic) in the molten phase. For example, it can be recognized by placing the sample on a hot stage, heating and heating the sample in a nitrogen atmosphere, and observing the transmitted light of the sample. The aromatic polyester used in the present invention is composed of repeating structural units such as aromatic diols, aromatic dicarboxylic acids, aromatic hydroxycarboxylic acids, and aromatic amines. Those consisting of combinations are preferred.

[0008]

Embedded image

[0009]

Embedded image

[0010]

Embedded image

Particularly preferred is a polymer comprising a combination of repeating structural units shown in Chemical formula 3. Especially (A)
And a polymer in which the portion composed of the repeating structural units of (B) is 65% by weight or more, and an aromatic polyester in which the component (B) is 5 to 45% by weight is particularly preferable.

The melting point (MP) of the molten liquid crystalline polyester is preferably from 260 to 360 ° C, more preferably from 270 to 350 ° C. The melting point referred to here is the peak temperature of the main endothermic peak observed by differential scanning calorimetry (DSC: for example, TA3000 manufactured by Mettler Co.) (JIS K7121). Specifically, D
An SC (e.g., TA3000 manufactured by Mettler Co.) device takes 10 to 20 mg of a sample, and the sample is sealed in an aluminum pan. Nitrogen is supplied as a carrier gas at a flow rate of 100 cc / min. Measure If a clear endothermic peak does not appear in the first run depending on the type of the polymer, the temperature is raised to a temperature 50 ° C. higher than the expected flow temperature at a temperature rising rate of 50 ° C./min. After melting completely for one minute, it is preferable to cool to 50 ° C. at a rate of 80 ° C./min and then measure the endothermic peak at a rate of temperature rise of 20 ° C./min.

The molten liquid crystalline polyester used as the A polymer in the present invention includes polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, and polyarylate as long as the effects of the present invention are not impaired. And a thermoplastic polymer such as polyamide, polyphenylene sulfide, polyether ether ketone, and fluororesin. Of course, a plurality of molten liquid crystalline polyesters can be used in combination. In addition, inorganic substances such as titanium oxide, kaolin, silica, and barium oxide;
It may contain various additives such as carbon black, coloring agents such as dyes and pigments, antioxidants, ultraviolet absorbers and light stabilizers.

The B polymer used in the present invention is not particularly limited as long as it is a flexible thermoplastic polymer. Polyolefin, polyamide, polyester, polycarbonate, polyphenylene sulfide, polyether ether ketone, Fluororesins and the like are mentioned, and those having a fiber forming ability are preferable. By using a sea-island structure composed of a flexible thermoplastic polymer and a molten liquid crystalline polyester as a sheath component, fibril resistance and mechanical performance are greatly improved. As the flexible thermoplastic polymer, those capable of performing composite spinning without decomposing at the spinning temperature of the core component are preferable, and include, for example, the repeating structural units (A) and (B) shown in Chemical formula 3 as the core component. When a polymer is used, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyether ether ketone, and the like can be suitably used. In particular, it is preferable to use polyphenylene sulfide (PPS) and polyethylene naphthalate. In particular, when PPS, particularly linear PPS, is used, the spinning processability is good, and remarkable effects are obtained in terms of chemical resistance, mechanical strength, abrasion resistance, etc., and the surface is smooth. An excellent effect is also obtained from the point that a rough undulation is easily formed. In addition, the flexible polymer referred to in the present invention is:
A polymer having no aromatic ring on the main chain and a polymer having an aromatic ring on the main chain and having four or more atoms on the main chain between the aromatic rings.

As the C polymer, the same molten liquid crystalline polyester as that of the A polymer can be used.
The polymers may be the same or different. Preferably, the melting point (MP) of the B polymer is + 80 ° C. or less,
Polymers at 10 ° C or higher are preferred. Further, the B polymer and the C polymer may contain other polymers and various additives to the extent that the effects of the present invention are not impaired.

According to the present invention, the sheath component comprises not only a flexible thermoplastic polymer (B polymer) but also a sea island comprising a flexible thermoplastic polymer (B polymer) and a molten liquid crystalline polyester (C polymer). By having a structure, the strength of the sheath component is enhanced, and at the same time, the adhesiveness between the sheath component and the core component is significantly enhanced. Such a sea-island structure can be obtained by chip blending a B polymer and a C polymer, or mixing a melt of both components by a static mixer or the like. In the present invention, since the sheath component is constituted by using a larger amount of the soft B polymer than the C polymer, a sea-island structure is formed in which the C polymer is an island component and the B component is a sea component (FIG. 1). (H)). In this case, the C polymer having rigidity and excellent mechanical performance constitutes an island component and has an excellent reinforcing effect, and the B polymer having excellent wear resistance forms a sea component and substantially surrounds the C polymer. It is considered that the wear resistance is remarkably improved due to the coating.

The sea-island structure according to the present invention refers to a state in which tens to tens of thousands of islands are present in a sea component serving as a matrix in a fiber cross section. Generally B polymer
The number of islands can be adjusted by changing the mixing ratio, melt viscosity, and the like of C and C polymers. From the viewpoint of fiber strength, fibril resistance, and undulation formation, it is expected that the island component is preferably fine.
It is considered that the thickness is preferably about 0.5 μm. The island component may be branched, and it is not necessary that the island component has the same length as the fiber length, and it is sufficient that the island component is continuous to the extent that the effects of the present invention can be obtained.

In order to increase the strength of the B polymer constituting the sheath component, it is necessary to stretch the fiber sufficiently to orient the B polymer, but the molten liquid crystalline polyester constituting the core component is spun without stretching. Alone has excellent mechanical performance, and the orientation is remarkably advanced in the state of the spun yarn. Therefore, even if it is attempted to further stretch the spun yarn in order to increase the strength of the sheath component, substantially no further stretching can be performed because the A polymer constituting the core component is highly oriented. As a result, the sheath component of the obtained composite fiber has low strength and is brittle, and the core component and the sheath component are easily peeled off, resulting in insufficient workability and wear resistance.

However, in the present invention, since the molten liquid crystalline polyester is blended with the sheath component, the affinity with the core component made of a similar polymer is increased, so that the core-sheath separation hardly occurs, and the sheath component is hardly separated. Is highly oriented in the state of a spun yarn, the strength of the sheath component is improved, and the abrasion resistance and the like are significantly improved. The compounding ratio C / (B + C) of the C polymer in the sheath component is 0.1.
05-0.50, especially 0.1-0.4, further 0.25
It is preferably set to 0.4 (weight ratio). If the compounding ratio of the C polymer is too high, the abrasion resistance becomes insufficient, and the processability such as weaving property becomes low because the fiber becomes rigid. Conversely, if the compounding ratio of the C polymer is too low, the strength of the sheath component becomes insufficient, the core-sheath peeling is likely to occur, the processability such as weaving property is reduced, and smooth undulation is hardly formed on the surface.

In the present invention, the core-sheath type composite fiber is used. Examples of the core-sheath type include an eccentric core-sheath type and a multi-core sheath type. The core component ratio in the composite fiber is preferably 0.25 to 0.80, particularly preferably 0.3 to 0.7. When the sheath component is composed of the B polymer and the C polymer, the sheath component also contributes to the improvement of the strength. Therefore, even when the core component ratio is reduced, it is possible to obtain an excellent composite fiber having a strength of 15 g / d or more. it can. If the core component ratio is too large, the core is likely to be exposed, and if it is too small, the strength may be insufficient. In addition, the core component ratio in the present invention indicates the cross-sectional area ratio A / (A + B + C) of the conjugate fiber.
The cross-sectional area ratio can be determined from a micrograph of the cross-section of the fiber, but can also be determined from the volume ratio of the discharge amount of the core component and the sheath component during production.

In the present invention, it is more preferable to form irregularities on the fiber surface. By forming the uneven portion, the adhesiveness with a resin or the like is improved, and various performances such as dimensional stability and homogeneity of the base material can be further improved. There is no particular limitation on the method of providing the uneven portion, and examples thereof include a method of spinning using a nozzle having a hole with an irregular cross section, a method of forming a fine shape by partial drawing, a method of containing a large number of inorganic fine particles in a polymer, and a fiber. Conventionally known methods such as a method of etching by chemical treatment after the formation and a method of etching by plasma treatment can be adopted.

By adopting such a method, a conjugate fiber having a large number of extremely fine irregularities can be obtained. However, since abrasion of the irregularities hardly occurs due to abrasion and a more remarkable effect can be obtained, the surface is gentle. It is preferable to use fibers having undulations. Various effects can be obtained by forming gentle undulations on the fiber surface. For example, heat treatment at higher temperatures becomes possible due to less sticking during heat treatment, and furthermore, frictional resistance is small and processability (weaving property etc.) is reduced. ), And the adhesiveness to a resin or the like is remarkably improved, and the dimensional stability and homogeneity of the base material are further improved. An excellent effect is obtained as compared with the conventional one in which a large number of extremely fine irregularities are formed, and an excellent effect is obtained even after weaving or the like since the undulation is hardly reduced by abrasion.

Preferred forms of the surface of the conjugate fiber used in the present invention include the following. First, a profile of the outer periphery of the fiber side surface of the fiber side photograph taken at a magnification of 1000 times with a scanning electron microscope was drawn, and the fiber length was 3D.
(D: average fiber diameter), the maximum point existing between L and the minimum point is S, and the distance from the center line to L is LL, and the distance from the center line to S is LS. LS difference (LL-LS) of more than 0.004D (NM) is 5 to 100, particularly 10
Approximately 50 exist. From the viewpoint of fiber strength and the like, LL-LS is 0.05D or less, particularly 0.03D.
It is preferred that: Note that the center line in the present invention is a straight line connecting the midpoints of the line segment a and the line segment b in the fiber diameter direction defined by the fiber length D (see FIG. 3).

Although the method for producing such a conjugate fiber is not particularly limited, it can be efficiently produced by spinning so as to satisfy the following conditions. MVc + 1100 ≧ MVb ≧ MVc + 350 Spinning temperature ≧ MPc + 30 ° C. γ (= 4Q / πr ³ ) ≧ 20,000 0.15 ≦ C / (B + C) ≦ 0.45 where MVb is the melt viscosity (poise) of B polymer, MVc
Is the melt viscosity (poise) of the C polymer, MPc is the melting point (° C.) of the C polymer, γ is the shear rate during spinning (sec-1), Q
Represents the amount of polymer discharged per single hole (cm3 / sec) when spinning the core-sheath composite fiber, and r represents the radius (cm) of the nozzle hole in the direction of the shear plane.

Although the mechanism of the formation of the gentle undulations is not clear, the high shear force is exerted when the C polymer forms fine island components and the viscosity of the C polymer is sufficiently lower than that of the B polymer. Is added, the island component composed of the C polymer is unevenly distributed in the vicinity of the fiber surface, and as a result, it is presumed that a smooth undulation is formed on the fiber surface due to the presence of the rigid C polymer in the vicinity of the surface. In particular, when a linear PPS is used as the B polymer, a fiber having gentle undulations on the surface can be efficiently produced.

The reason why the smooth undulations are not formed when the deviation from 0.15 ≦ C / (C + B) ≦ 0.45 is not obvious, but the undulation on the fiber surface is that the C component constitutes the island component. Therefore, it is considered that if the C component ratio is too small, it is difficult to form smooth undulations. Conversely, if the ratio of the C component is too large, the C component becomes an island component and the B component tends to become a sea component, and a desired fiber cannot be obtained. From the above, it is preferable that the C component ratio be 0.45 or less, particularly 0.40 or less. In addition, undulation formation,
From the viewpoint of mechanical performance and prevention of peeling of the core-sheath component, it is preferable to set the value of 0.1%.
It is preferably at least 25. The island component ratio can be determined from a micrograph of the cross section of the fiber, but can also be determined from the volume ratio of the ejection amount of the core component and the sheath component during production. Further, when such an island component ratio is used, an excellent effect can be obtained in terms of fiber strength and fibril resistance. In addition, C compounding ratio:
C / (B + C) indicates the weight mixing ratio of the sheath component.

In order to form desired undulations by the above method, γ must be 20,000 or more,
As described above, it is particularly preferable to set the molecular weight to 40,000 or more. The reason for this is not clear, but it is considered that island components composed of C polymer are more likely to be unevenly distributed near the fiber surface by increasing the shear rate. 80 in terms of spinnability
It is preferably set to 000 or less.

When the above method is employed, the spinning temperature must be set to MPc + 30 ° C. or higher. The reason for this is not clear, but it is considered that if the spinning temperature is too low, the viscosity of the C polymer is not sufficiently reduced, so that it is impossible for the island component composed of the C polymer to be unevenly distributed near the fiber surface. However, if the spinning temperature is increased, decomposition or the like may occur, so that the temperature is preferably set to MPc + 60 ° C. or lower. From the viewpoint of fiber performance, the spinning speed is preferably at least 650 m / min, more preferably at least 900 m / min. From the viewpoint of spinning stability, it is preferably at most 3000 m / min.

The MVb is preferably (MVc + 1100) poise or less from the viewpoint that spinnability and a fiber having a small yarn diameter are easy to obtain, and from the viewpoint of undulation formation, MVb + 350.
It is preferably at least poise, especially at least MVc + 400 poise. Further, from the viewpoint of undulation forming property, spinnability and abrasion resistance, the viscosity of the C polymer is 600 poise or less,
In particular, it is preferably 500 poise or less, and from the viewpoint of the mechanical strength of the fiber, it is preferably 380 poise or more. The conjugate fiber used in the present invention can be spun, for example, using a conventionally known spinneret. Although the cross-sectional shape of the obtained fiber is not particularly limited, for example, a shape as shown in FIG. 1 is a preferred example. In (a) to (g), the description of the sea-island structure is omitted.

The fiber obtained according to the present invention is excellent in various performances. The fiber has sufficient strength and elastic modulus by spinning, but the performance is further improved by performing a relaxation heat treatment or a tension heat treatment. Can be done. The heat treatment causes a solid phase polymerization and a cross-linking reaction to increase the melting point of the polymer and improve the mechanical performance of the fiber. As a specific example, a molten liquid crystalline polyester comprising the structural units (A) and (B) shown in Chemical Formula 3 (molar ratio A /
When the fiber consisting of (B = 75/25) was heat-treated at various temperatures, any fiber whose peak temperature exceeded 300 ° C. was no longer melted under normal temperature pressure, and when the temperature was further raised, it was carbonized while maintaining the fibrous state. This is presumed to be because a cross-linking bond was formed inside the fiber by the heat treatment. From the viewpoint of fiber performance, it is preferable to increase the melting point of the core component by 10 ° C. or more by heat treatment.

The heat treatment can be performed in an atmosphere of an inert gas such as nitrogen, an atmosphere of an active gas containing oxygen such as air, or under reduced pressure. Heat treatment atmosphere has a dew point of -4
A low humidity gas of 0 ° C. or lower is preferred. Preferred heat treatment conditions include a melting point of the core component of −40 ° C. or lower and a sheath component polymer.
Temperature pattern in which the temperature is gradually raised to the melting point or lower. The processing time is from several seconds to several tens of hours depending on the purpose. Since the rate of increase in the melting point greatly depends on the processing temperature and the processing time, it is preferable to appropriately set the rate.

The heat is supplied by a method using a medium such as a gas,
A method using radiation by a heating plate, an infrared heater, or the like,
There are 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 shape of the heat treatment may be a scallop shape, a tow shape (for example, carried on a metal net or the like), or a continuous treatment between rollers.

The treatment is carried out under tension or without tension depending on the purpose. The shape of the treatment may be a scallop shape, a tow shape (for example, performed on a metal net or the like), or a continuous treatment between rollers. Although heat treatment may be performed before processing into a fabric or the like, it is preferable to perform heat treatment after processing into a fiber structure such as a fabric from the viewpoint of processability. The tension heat treatment is preferably performed at a temperature of not more than the melting point of the core component −40 ° C. and applying a tension of 1 to 10% of the cutting strength, and this treatment further improves various performances, particularly elasticity.
In the case where gentle undulations are formed on the fiber surface, an excellent effect can be obtained, in which the fibers do not easily adhere to each other even by heat treatment.

From the viewpoint of the mechanical performance and dimensional stability of the printed wiring board, the core-sheath type composite fiber has a strength of 10 g / d or more, an elastic modulus of 400 g / d or more, a strength of 12 g / d or more, and an elastic modulus of 450 g / d. d or more, and more preferably, the strength is 16 g / d or more, and the elastic modulus is 500 g / d or more. Further, from the viewpoint of adhesion to the matrix resin and homogeneity, the diameter of the core-sheath type composite fiber is preferably 45 μm or less, particularly 40 μm or less, more preferably 35 μm or less, and further preferably 33 μm or less. When the fiber diameter is 35 μm or less, particularly 33 μm or less, the adhesiveness to the resin is enhanced, and the homogeneity is also improved.

The use of such a conjugate fiber gives a printed wiring board excellent in various performances, but the form of use of the conjugate fiber is not particularly limited. It can be used in any form such as monofilament, multifilament, cut fiber, spun yarn, fabric (woven or knitted fabric, nonwoven fabric, etc.). For example, various performances can be obtained by using a prepreg integrated with the fiber structure and resin as a base material. A printed wiring board excellent in quality can be obtained. At this time, a component (fiber or the like) other than the conjugate fiber may be used in combination as long as the effects of the present invention are not impaired. From the viewpoint of the uniformity and dimensional stability of the printed wiring board, it is preferable to use it in the form of a fabric. Of course, the fabric may be manufactured in combination with other fibers, but from the viewpoint of more efficiently obtaining the effects of the present invention, the proportion of the conjugate fiber specified in the present invention is 50% by weight or more, and more preferably 8% or more.
The fabric is preferably 0% by weight or more, particularly 90% by weight or more.

From the viewpoint of resin impregnating property, mechanical performance, handleability, flexibility, etc., the thickness of the cloth should be 20 to 800 μm, especially 1 to 800 μm.
It is preferable to set it to 00 to 500 μm. The conjugate fiber used in the present invention is excellent in mechanical performance and also excellent in fibril resistance. Therefore, even when the thickness of the cloth is reduced, a sufficient reinforcing effect can be obtained, and the fibrils are substantially not generated, and since the thickness is small, the defect (the portion where no resin is present) is caused. An excellent effect can be obtained because it hardly occurs and the amount of resin can be reduced. For the same reason, the basis weight of the fabric is 10 to 100 g / m.
² , particularly preferably 20 to 60 g / m ² .

It is preferable to use a woven fabric as a constituent material of the printed wiring board from the viewpoint of manufacturing process, resin impregnation, homogeneity, and the like.
Above all, it is preferable to use in the form of a plain fabric, and from the viewpoint of homogeneity and the like, the density is preferably 200 mesh or more, particularly 250 mesh or more, and more preferably 300 mesh or more. 3 in terms of productivity
The mesh size is preferably 50 mesh or less, particularly 330 mesh or less. In general, it is difficult to process a molten liquid crystalline polyester fiber into a woven fabric because of its low fibril resistance, and particularly when processed into a dense woven fabric, a large number of fibrils are formed in the fabric. Although it is difficult to integrate them, the homogeneity and electrical characteristics of the wiring board are impaired, but in the present invention, such a problem does not occur because fibrils are not substantially formed.

The method for producing the woven fabric is not particularly limited. For example, it is preferable that the woven fabric is woven by a known method using the core-sheath type composite fiber as a warp and / or a weft. Devising the weaving structure, devising the form of the entangled portion of the yarn, interweaving fibers of different thicknesses, using relatively flexible fibers, or combining them as appropriate Good. From the viewpoints of processability, homogeneity, resin impregnation, abrasion resistance, etc., it is preferable to use a mesh fabric using composite monofilaments.

From the viewpoint of uniformly impregnating the resin with no gap and maintaining the homogeneity of the wiring board, the opening ratio should be 30% or more, especially 35%.
As described above, it is more preferable that the content be 40% or more and 60% or less.
By increasing the opening area, defects (portions where no resin or the like is present) are less likely to be formed, and the adhesion to the resin is improved, so that a more favorable effect is obtained. The term "opening ratio" as used in the present invention refers to the ratio of openings (portions where no fibers exist) when the fabric is viewed in plan.

In addition, the mechanical performance and dimensional stability of the wiring board
From the strength of the fabric is 10kg / mm ²Preferably
Preferably, especially 20-100 kg / mm²Prefer to
Preferably, the elongation is 3% or less. Also dry heat 2
Those that do not substantially shrink when heat-treated at 00 ° C
Is preferred.

In the present invention, a treatment such as a physical treatment and / or a chemical treatment may be performed in order to enhance the adhesiveness between the matrix resin and the substrate. Specifically, corona discharge treatment, glow discharge treatment, plasma treatment,
Examples include physical treatment such as electron beam irradiation treatment, ultraviolet irradiation treatment, heat treatment in an oxygen-containing atmosphere, and chemical treatment such as sputter etching. These two or more treatments may be performed in combination. When the heat treatment for the solid-phase polymerization is performed in an oxygen-containing atmosphere, the adhesiveness and wettability with the resin can be significantly improved without performing another treatment. Heat treatment at 200-400 ° C for more than 1 minute,
Particularly at 300 to 400 ° C. for 1 minute or more, 3
The heat treatment is preferably performed for a time period of 0 hour or less, and may be performed in the same step as or a separate step from the heat treatment for the purpose of solid-phase polymerization. Further, a hot press treatment may be performed at a temperature equal to or higher than the softening point of the flexible thermoplastic polymer constituting the sheath component, and a part or all of the sheath component may be fused to suppress misalignment of the fiber. By adjusting the conditions of hot pressing or heat pressing, the fibers may be fused between some or all of the fibers constituting the fabric.
However, from the viewpoint of resin impregnation, it is preferable to adopt a method that does not reduce the opening ratio.

The method for producing a printed wiring board of the present invention is not particularly limited. For example, a prepreg containing the composite fiber is produced, and if necessary, another layer is laminated and then a conductive film made of copper or the like is integrated. Thus, a wiring board can be manufactured. As the resin integrated with the composite fiber, a thermosetting resin and / or a thermoplastic resin (matrix resin) may be used. Among them, phenol resin, epoxy resin, unsaturated polyester resin, epoxy resin, unsaturated polyester One or more thermosetting resins selected from a resin, a cyanate resin, a maleimide resin, a polyimide resin and the like can be suitably used. The content of the matrix resin in the prepreg is not particularly limited. However, in order to suppress delamination and poor molding, and to improve the mechanical performance, dimensional stability, and thermal stability of the laminate, the total weight of the prepreg is 30%.
It is preferable that about 95% by weight, particularly 40 to 80% by weight, be the matrix resin.

The method of impregnation and application of the resin is not particularly limited.
For example, 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 cloth with a varnish prepared by dissolving a matrix resin in a solvent and drying the cloth, a method of impregnating a cloth with a liquid matrix resin in a room temperature state or a heated state prepared without using a solvent, a matrix resin in a powder state And a method of forming a matrix resin layer on a film or sheet having releasability and then transferring it to the fabric. Since the fibril substrate of the present invention has substantially no fibrils and is excellent in resin impregnating property, the entire fabric can be impregnated with the resin substantially, and an excellent effect can be obtained. When the impregnated and adhered matrix resin is dried, it is preferable to dry it in a non-contact state by a vertical dryer. Of course, a prepreg can be manufactured by uniformly mixing a filament, a cut fiber, a spun yarn or the like made of a conjugate fiber with a matrix resin.

A printed wiring board may be manufactured using at least one prepreg. Specifically, a substrate made of the prepreg single layer, a substrate formed by laminating two or more prepregs, one or more prepregs and another material (for example, glass cloth, glass nonwoven fabric, other fiber cloth or porous substrate). Materials, plastic sheets, plastic films, plastic plates, etc.). From the viewpoint of effectively obtaining the effects of the present invention, it is preferable that the printed wiring board is composed of substantially only the prepreg obtained by impregnating the base material of the present invention with a resin, and the mechanical performance, the electrical characteristics, and the workability. From the viewpoint of the above, it is more preferable to manufacture a substrate by laminating about 2 to 5 prepregs.

A printed wiring board can be obtained by laminating a conductive film, preferably a metal layer, on such a printed wiring board. The conductive film does not need to be a single layer, and may be formed in a plurality of layers. Examples of the metal layer include a metal foil, a metal sheet, a metal plate, a metal net, and the like. In some cases, these may be used in combination, and the metal layer may be subjected to a surface treatment or the like. Copper, iron, aluminum and the like can be suitably used as the metal constituting the metal layer.
More than one species may be used in combination. The thickness of the metal layer is preferably about 10 to 50 μm from the viewpoint of handleability and electrical characteristics. The metal layer and the multilayer may be bonded using an adhesive in some cases.

The method for manufacturing the wiring board is not particularly limited. For example, the wiring board may be manufactured in the same manner as a conventionally known method. For example, one or two or more prepregs obtained by impregnating the base material of the present invention with a resin are used (and other base materials are used if necessary). The desired wiring board can be manufactured by hardening and / or solidifying and bonding between layers. 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.

As a more preferable method, a printed wiring is formed by applying a conductive substance to a part of a cloth (preferably a woven cloth) so as to penetrate both sides of the cloth and forming a circuit pattern with the conductive substance. A method for manufacturing a plate is included. According to this method, a printed wiring board having flexibility and excellent handleability can be efficiently manufactured. In general, a printed wiring board is manufactured by forming a conductive layer on a prepreg containing fibers. At this time, it is necessary to perform a through-hole treatment to make the continuity, so that much labor is required. However, if the above-mentioned method is adopted, since a conductive portion is formed without the fiber in the fabric, a desired portion can be impregnated with a conductive substance to perform the desired process without performing through-hole treatment. Is obtained. From the viewpoint of the flexibility of the wiring board and the like, it is preferable that portions other than the circuit pattern are not impregnated with resin or the like. Specifically, the amount of resin or the like applied to portions other than the circuit pattern portion is 10% by weight or less /
It is preferable that the ratio is 5% by weight or less / wiring board.

The conductive substance is not particularly limited.
Metals such as iron and aluminum are preferably used. Of course, the circuit pattern does not need to be composed only of a conductive material, and a desired portion may be impregnated with a resin or the like, and the portion may be covered with a conductive material to form the circuit pattern. Although a specific method is not particularly limited, for example, a method of applying a metal paste to a desired portion by a screen printing method, or a method of impregnating a cloth with a photosensitive emulsion and performing exposure and development, and then using a photomask or the like After exposing the emulsion at the desired site, the unexposed emulsion is removed, a conductive material is applied to the removed portion, and then the remaining emulsion is substantially completely removed. Further, the photosensitive emulsion is impregnated into the fabric, exposed and developed, and the emulsion at a desired portion is exposed and insolubilized (cross-linking reaction or the like) using a photomask or the like, and remaining after removing the unexposed emulsion. A method of forming a desired circuit pattern by coating the emulsion (insoluble) with a conductive material may be employed. Further, a fabric on which a wiring pattern obtained by such a method is formed and another layer may be laminated and used.

Since the fabric used in the present invention has no fibrils or the like, it can be impregnated with a resin, an emulsion or the like without a defect, and as a result, a desired circuit pattern can be efficiently and precisely formed. In particular, when the fabric is a dense mesh fabric and the opening ratio is high, the effect is remarkably improved. In the present invention, since a composite fiber having excellent performances is used, the opening ratio can be increased even when a fine mesh is used, and as a result, a dense and accurate pattern can be formed. The printed wiring board of the present invention is excellent in various performances such as dimensional stability, mechanical performance, electrical properties, heat resistance, homogeneity, and non-hygroscopicity, and can be applied to various uses.

[0050]

Next, the present invention will be described in more detail with reference to specific examples. It should be noted that the present invention is not limited to the examples described below. In addition, the measuring method of the physical property measured in the Example is shown below.

[Melt viscosity (MV) poise] Measured using a Capillograph 1B manufactured by Toyo Seiki Co., Ltd. under the conditions of 300 ° C. and shear rate r = 1000 sec ⁻¹ . [Logarithmic viscosity (ηinh)] A sample is dissolved in pentafluorophenol at 0.1% by weight (60 to 80 ° C), and the relative viscosity (ηinh) is measured using an Upperode viscometer in a thermostat at 60 ° C.
rel) was measured and calculated by ηinh = ln (ηrel) / c. Here, c is the polymer concentration (g / dl).

[Strength g / d] According to JIS L 1013, using a strong elongation tester DCS-100 manufactured by Shimadzu Corporation, test length 20 cm, initial load 0.1 g / d, tensile speed 1
A tensile breaking test was performed under the condition of 0 cm / min, and the value was obtained from the obtained stress-strain curve. 5
The average of the measured values above the point was adopted. [Elastic modulus g / d] According to JIS L 1013, using a strong elongation tester DCS-100 type manufactured by Shimadzu Corporation, test length 20 cm, initial load 0.1 g / d, tensile speed 10 cm / m
A tensile rupture test was performed under the conditions of “in”, and from the obtained stress-strain curve (Stress-StrainCurve), the elastic modulus = (w / D)
/ (ΔL / L). In addition, w is the load (g) when ΔL is elongated, D is the denier (d) of the fiber, ΔL is the length (mm) elongated by the load, and L is the original fiber length.

[Fiber diameter μm] 1000 by scanning electron microscope
A photograph of the side of the fiber magnified twice was taken, the fiber diameter was measured at any 10 points, and the arithmetic average was defined as the fiber diameter. [Undulation (NM) pieces / D] A photograph of the fiber side surface was taken at a magnification of 1000 times with a scanning electron microscope, the profile of the fiber side outer periphery was drawn, and the maximum existing between the fiber lengths 3D (D: fiber average diameter) When the point is L, the minimum point is S, and the distance from the center line to L is LL, and the distance from the center line to S is LS, the difference (LL-LS) between adjacent LL and LS is 0.005D. The number of larger ones (NM) was determined for both sides of the fiber. The same operation was repeated for another fiber portion, and the average value of the total number of NMs on both side surfaces was obtained (N ≦ 3). The center line in the present invention refers to a fiber length of 3D.
Is a straight line connecting the midpoints of the line segment a and the line segment b in the fiber diameter direction (see FIG. 3).

[Tensile strength of fabric kg / 2.5 cm Strength (tear) kg / m ² , elongation%] JIS L10
It measured according to 96.

[Matrix resin (varnish)] 2,2-
900 parts by weight of bis (4-cyanatophenyl) propane and 100 parts by weight of bis (4-maleidophenyl) methane
After a preliminary reaction at 50 ° C. for 130 minutes, the resulting product was dissolved in 60 parts by weight of a mixed solvent of methyl ethyl ketone and N, N-dimethylformaldehyde. To 50 parts by weight of the obtained solution, bisphenol A epoxy resin (“Epoquito 1001” manufactured by Yuka Shell Epoxy Co., Ltd.)
(Epoxy equivalent = 450-500) 70 parts by weight and zinc octylate 0.02 parts by weight were dissolved to prepare a matrix resin liquid (varnish).

[Reference Example 1] As the A polymer and the C polymer, the structural units (A) and (B) represented by the above-mentioned formula (3) were 75 /
25 mol% of a molten liquid crystalline polyester (melting point: 281
° C, melt viscosity 410poise, ηinh = 5.6dl /
g) and using linear PPS (MVb11
00poise, MPb 280 ° C).

First, using a B polymer and a C polymer,
Mixed pellets with C mixing ratio C / (B + C) = 0.33
Was prepared by kneading with a twin-screw extruder. Next, the core component and the sheath
And the melt is fed to a separate extruder, and after melting, the sheath component ratio R = 0.
Approximately 9 denier (wire diameter
30.3 μm) core-sheath composite fiber (strength 18 g / d, bullet
Composite rate was 700 g / d, and NM4) was composite-spun. Nozzle hole diameter: 2r = 0.015 cm Polymer discharge amount per unit hole: Q = 0.015 cm^Three/ Sec Shear rate: γ = 44300 sec^-1  Spinning speed: 1100 m / min Spinning temperature: 315 ° C

[Reference Example 2] Linear PPS as B polymer
(MVb 600 poise, MPb 279 ° C.) except for using about 9 denier (wire diameter 30.3 μm) as in Reference Example 1.
Core-sheath type composite fiber (strength 17.5 g / d, elastic modulus 650)
g / d, NM0). Reference Example 3 A core-sheath type composite fiber of about 9 denier (wire diameter 30.3 μm) (strength 12.0 g / d, elastic modulus 450 g) in the same manner as in Comparative Example 1 except that the sheath component was composed of only the B polymer.
/ D, NM0).

Example 1 A plain fabric is woven using the monofilament fiber obtained in Reference Example 1 as a warp and a weft, and then the plain fabric is woven in a nitrogen atmosphere at 260 ° C. for 2 hours and then in a dehumidified air at 270 ° C. Heat treatment was performed at 4 ° C. for 4 hours. The obtained woven fabric is about 250 mesh, and the opening ratio is 49.
%, Basis weight 40 g / m ² , thickness 91 μm, tensile strength 60 k
g / 2.5cmm, strength 26.4kg / m ² , elongation 3%
The heat-shrinkage did not substantially occur even at a dry heat of 200 ° C. Further, substantially no core-sheath peeling or fibrils were generated, and the product was excellent in homogeneity. The melting point (endothermic peak temperature) of the core component after the heat treatment was 330.
° C.

Next, screen printing was performed on the woven fabric using a conductive paste, and a conductive pattern was applied to a desired portion so that the conductive paste penetrated both sides of the cloth to form a circuit pattern. Since the mesh fabric is dense and has a large opening ratio, and the surface of the constituent fibers has gentle undulations, the adhesiveness between the fabric and the conductive paste is good. In this case, a printed wiring board was obtained in which the desired circuit pattern was formed densely and accurately, with excellent uniformity, electrical characteristics, mechanical performance, and the like. Further, the wiring board was excellent in flexibility and light weight and excellent in workability, since no resin or the like was present in a portion other than the circuit pattern.

Example 2 A plain fabric is woven using the monofilament fiber obtained in Reference Example 1 as a warp and a weft, and then the plain fabric is woven in a nitrogen atmosphere at 260 ° C. for 2 hours and then in a dehumidified air at 270 ° C. Heat treatment was performed at 4 ° C. for 4 hours. Approximately 250 mesh obtained, 49% opening ratio,
Weight 40g / m ² , thickness 91μm, tensile strength 60kg /
It was 2.5 cm, strength 26.4 kg / m ² , elongation 3% or less, and substantially no heat shrinkage even at 200 ° C. dry heat. Further, it was excellent in homogeneity with substantially no core-sheath peeling or fibril generation. The melting point (endothermic peak temperature) of the core component after the heat treatment was 330 ° C.

Next, the woven fabric is impregnated with a matrix resin solution (varnish) and dried at 150 ° C. to obtain a resin content of 66-6.
An 8% by weight prepreg was manufactured, four prepregs were stacked, and a copper foil having a thickness of 35 μm was laminated on both surfaces thereof. The laminate was placed between stainless steel mirrors and a pressure of 4
Laminate molding is performed by pressurizing and heating for 2 hours under the conditions of 0 kg / cm ² and a temperature of 200 ° C., and a thickness of 0.40 to 0.45 m
m of printed wiring boards were manufactured. Since the mesh fabric is dense and has a large opening ratio, and the surface of the constituent fibers has gentle undulations, it has good adhesion to the resin and has few defects (parts where no resin exists). A printed wiring board excellent in various performances such as uniformity, electrical characteristics and the like was obtained.

Example 3 A plain fabric is woven using the monofilament fiber obtained in Reference Example 2 as a warp and a weft, and then the plain fabric is woven in a nitrogen atmosphere at 260 ° C. for 2 hours and then in a dehumidified air at 270 ° C. Heat treatment was performed at 4 ° C. for 4 hours. The obtained woven fabric is about 250 mesh, and the opening ratio is 49.
%, Basis weight 40 g / m ² , thickness 91 μm, tensile strength 57 k
g / 2.5cmm, strength 25.1kg / m ² , elongation 3%
The heat-shrinkage did not substantially occur even at a dry heat of 200 ° C. Further, it was excellent in homogeneity with substantially no core-sheath peeling or fibril generation. The melting point (endothermic peak temperature) of the core component after the heat treatment was 330.
° C. Next, a printed wiring board was manufactured in the same manner as in Example 1 using the woven fabric. Although not as good as in Example 1, the double wiring board has good adhesion between the resin and the fabric, and has few defects (parts where no resin is present) and good homogeneity, electrical properties, mechanical performance, and flexibility. Met.

Comparative Example 1 A plain woven fabric was woven using the monofilament fiber obtained in Reference Example 3 as a warp and a weft, and then the plain woven fabric was placed in a nitrogen atmosphere at 260 ° C. for 2 hours, and then 270 in dehumidified air. Heat treatment was performed at 4 ° C. for 4 hours. The obtained woven fabric has a mesh size of about 300 and an opening ratio of 41.
%, Basis weight 58 g / m ² , thickness 98 μm, tensile strength 48 k
g / 2.5cmm, strength 21.1kg / m ² , elongation 3%
It was below. The woven fabric had core-sheath peeling, fibrils, and the like, and had poor mechanical performance and dimensional stability. Next, a printed wiring board was manufactured using the woven fabric in the same manner as in Example 1. However, since a large number of fibrils were generated in the woven fabric, a large number of defects (portions where no resin was present) were formed in the composite. Moreover, since the opening ratio is small, the adhesiveness of the resin is more likely to be reduced. Also, the mechanical performance of the wiring board was insufficient.

[0065]

According to the present invention, a printed wiring board excellent in various performances such as dimensional stability, mechanical performance, homogeneity, and electrical characteristics can be obtained, and particularly, the printed wiring board has a gentle surface on the fibers constituting the wiring board. Even better effects can be obtained when undulations are formed or when a mesh fabric having a large opening ratio is used.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a cross-sectional shape of a conjugate fiber used in the present invention. In (a) to (g), the description of the sea-island structure is omitted.

FIG. 2 is a photograph substituted for a drawing, and is a scanning electron micrograph showing an example of the surface shape of a conjugate fiber having gentle undulations on the surface.

FIG. 3 is a schematic diagram showing an example of a shape of a fiber side surface.

[Explanation of symbols]

A: A polymer B: B polymer C: C polymer 1: Fiber 2: Fiber outer peripheral outline a: Line segment a b: Line segment bc: Connected the middle point of line segment a and the middle point of line segment b Center line L: Local maximum point on fiber side surface S: Local minimum point on fiber side surface LL: Distance between L and center line LS: Distance between S and center line T: Portion having pattern of line width / line interval = 60/100 μm K: A portion having a pattern of line width / line interval = 100/100 μm

Claims (7)

[Claims] 1. A core component comprising a molten liquid crystalline polyester (A polymer), a sheath component comprising a flexible thermoplastic polymer (B polymer) as a sea component and a molten liquid crystalline polyester (C polymer) as an island component. A printed wiring board using a core-sheath composite fiber composed of a sea-island component. 2. A core component comprising a molten liquid crystalline polyester (A polymer), a sheath component comprising a flexible thermoplastic polymer (B polymer) as a sea component and a molten liquid crystalline polyester (C polymer) as an island component. A printed wiring board using a woven fabric containing a core-sheath composite fiber composed of a sea-island component. 3. A core component is a molten liquid crystalline polyester (A polymer), a sheath component is a flexible thermoplastic polymer (B polymer) as a sea component, and a molten liquid crystalline polyester (C polymer) is an island component. Printed wiring board using prepreg and conductive film obtained by impregnating resin into woven fabric containing core-in-sheath type composite fiber composed of sea-island component 4. A core component comprising a molten liquid crystalline polyester (A polymer), a sheath component comprising a flexible thermoplastic polymer (B polymer) as a sea component and a molten liquid crystalline polyester (C polymer) as an island component. A printed wiring board in which a conductive material is applied to a part of a woven fabric including a core-sheath conjugate fiber composed of a sea-island component so as to penetrate both sides of the woven fabric, and a circuit pattern is formed by the conductive material. 5. A woven fabric having a density of 200 to 500 mesh and an opening ratio of 30% or more.
The printed wiring board according to any one of the above. 6. The printed wiring board according to claim 1, wherein a gentle undulation is formed on the surface of the core-sheath composite fiber. 7. A core component is a molten liquid crystalline polyester (A polymer), a sheath component is a flexible thermoplastic polymer (B polymer) as a sea component and a molten liquid crystalline polyester (C polymer) is an island component. A printed wiring board constituent material composed of a woven fabric containing a core-sheath type composite fiber composed of a sea-island component.