JP2001064845A - Base fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a base fabric excellent in dimensional stability and having high strength and high modulus and, especially, a base fabric of extra-thin type, having high strength and high dimensional stability and applied in electronics territory as a substrate. SOLUTION: This fabric comprises a fiber composed of a core component (X) and a sheath component (Y) wherein the core component comprises a melt- anisotropic aromatic polyester and the sheath component comprises a sea component (A) of a flexible polymer and an island component of a melt-anisotropic aromatic polyester (B) dispersed in the sea component A and is characterized by agglutinating or fusing the sea component at intersecting points of the fablic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base fabric having excellent dimensional stability and high strength and high elastic modulus. In particular, an object of the present invention is to provide an ultra-thin, high-strength, high-dimensional stability base fabric for substrates used in the electronics field.

[0002] In recent years, there has been a demand for weight reduction and thickness reduction in the electronics industry. However, the substrate is required to have heat resistance, dimensional stability, and workability for multi-layering, and sufficient lightening and thinning have not been realized. In other words, a substrate using a glass fiber woven fabric as a base fabric is mainly used, and although a woven fabric or a nonwoven fabric made of aramid or polyarylate fibers is being improved, it is not in a situation where it has many problems and is not sufficiently satisfactory.

[0003]

The base fabric obtained from high-strength, high-modulus fibers made of aramid or polyarylate certainly has excellent performance. However, since these fibers are easily fibrillated by friction, weaving is difficult. In particular, it has been extremely difficult to obtain a high-density woven fabric using low-denier multifilaments. Therefore, it was not possible to obtain a low-weight, high-strength woven fabric. Further, even if a woven fabric is obtained, since the resin impregnation is required, the weight per unit area of the substrate is increased or the strength is reduced.

In order to provide a thin and strong sheet-like material having good dimensional stability, one of the present inventors has used a composite fiber whose core is made of a molten liquid crystalline polymer and whose sheath is a flexible polymer, The above-mentioned sheet-like material is obtained by heat-treating a cloth comprising the same to increase the melting point of the core component by 10 ° C. or more, and then performing hot pressing at a temperature not lower than the softening point of the sheath component to fuse at least a part of the sheath component. A possible invention has already been proposed (JP-A-5-44146).
However, also in the present invention, a sheet-like material that satisfies the desired properties needs to have a thickness of 50 μm or more. It has been found that a problem arises in that the sheath component is peeled off partially during weaving, and that the sheath component may flow due to calendering (hot pressing) of the fabric, resulting in uneven thickness of the resulting sheet. did. The present invention is intended to overcome the problems of the above-described known techniques, and in particular, even in an ultra-thin sheet having a thickness of 50 μm to 10 μm, high strength, excellent dimensional stability, and It is an object of the present invention to provide a sheet having no thickness unevenness.

[0005]

According to the present invention, a core component (X) is provided.
Is a melt-anisotropic aromatic polyester, and a sheath component (Y) is a woven fabric comprising fibers composed of an island made of a flexible polymer and the sea (A) and the melt-anisotropic aromatic polyester (B). At the intersection of, the sea component is stuck or fused.

The present invention provides a woven fabric comprising a core-sheath composite fiber having a melt-anisotropic aromatic polyester as a core component and a glue / fusion component as a sheath component. In the weaving process, instead of using a component consisting only of a hydrophilic polymer, by blending the melt-anisotropic aromatic polyester used in the core component in a dispersed state as an island component in the flexible polymer, The above-mentioned ultra-thin sheet, which could not be reached until now, can eliminate all problems such as peeling of the sheath component and occurrence of thickness unevenness of the sheet-like material due to the flow of the sheath component in the hot press. It is now possible to obtain a shape.

[0007] The term "melt anisotropy" as used in the present invention means that the melt phase exhibits optical anisotropy (liquid crystal properties). For example, it can be recognized by placing the sample on a hot stage, heating it in a nitrogen atmosphere, and observing the transmitted light of the sample. The melt-anisotropic aromatic polyester constituting the core component referred to in the present invention comprises repeating structural units of aromatic diol, aromatic dicarboxylic acid, and aromatic hydroxycarboxylic acid. Those comprising a combination of repeating units shown in (1) are preferred.

[0008]

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Particularly preferred is a polymer consisting of (5), (8) and (9) among the combinations of repeating structural units shown in Chemical Formula 1, and more preferably HNA of Chemical Formula 2
An aromatic polyester whose component is 4 to 45% by weight.

[0010]

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The melting point (MP) of the preferred melt anisotropic polyester is from 250 to 350 ° C., more preferably from 260 to 350 ° C.
320 ° C. The melting point referred to here is a peak temperature of a main endothermic peak observed by a differential scanning calorimeter (DSC: for example, TA3000 manufactured by Mettler) (JIS).
K7121). Specifically, sample 10 to DSC
After taking 20 mg and enclosing in an aluminum pan, nitrogen is supplied as a carrier gas at a flow rate of 100 cc / min, and an endothermic peak is measured when the temperature is raised at 20 ° C./min. If a clear endothermic peak does not appear in the first run depending on the type of polymer, the temperature is raised at a heating rate of 50 ° C./min to a temperature 50 ° C. higher than the expected flow temperature, and the temperature is increased. After holding for 3 minutes or more and melting completely,
Cool to 50 ° C. at a rate of 0 ° C./min.
The endothermic peak may be measured at a rate of temperature rise in minutes.

The melt anisotropic aromatic polyester used as the core component (X) polymer in the present invention includes polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, and the like, as long as the effects of the present invention are not impaired. Polyphenylene sulfide, polyetheresterketone, fluororesin, or the like may be added. In addition, various additives such as inorganic substances such as titanium oxide, silica and barium oxide, carbon black, coloring agents such as dyes and pigments, antioxidants, ultraviolet absorbers and light stabilizers may be contained.

The melt-anisotropic aromatic polyester (B) which is an island component in the sheath component may be the same as or different from the core component (Y).

The flexible polymer (A) referred to in the present invention includes thermoplastic polymers having a fiber-forming ability, such as polyolefin, polyamide, polyester, polyarylate, polycarbonate, polyphenylene sulfide, polyester ether ketone, and fluoro resin. A preferred example is a polymer having a melting point similar to that of the melt-anisotropic aromatic polyester (B) as an island component.

More preferred flexible polymer (A) components are polyphenylene sulfide (PPS), polyethylene naphthalate (PEN) and semi-aromatic polyamide. These polymers have particularly high second order transition temperatures and are suitable for the purposes of the present invention.

The semi-aromatic polyamide referred to in the present invention is a polyamide obtained by polymerizing an aromatic dicarboxylic acid and an aliphatic diamine, and preferably has a repeating structure of the following chemical formula 3, more preferably n = 6 to 12.

[0017]

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The preferred core-sheath ratio of the composite fiber of the present invention [Y /
(X + Y)] is 0.2 to 0.65. If it is less than 0.2, the sheath component is small, so that the sufficient fusibility intended for the present invention cannot be obtained. Conversely, if it exceeds 0.65, sufficient strength of the base fabric cannot be obtained.

The preferred island-sea ratio [B / (A + B)] of the sheath component in the present invention is 0.15 to 0.5. 0.
If it is less than 15, the sea component of the flexible polymer flows, and the dimensional stability (low linear expansion coefficient) of the base fabric, which is a major feature of the present invention, cannot be achieved. Conversely, if it exceeds 0.5, the sea component as a fusion component decreases, and it becomes impossible to fuse the intersections of the woven or knitted fabric firmly to have a sufficient adhesive strength.

The fiber of the present invention can be prepared by a known method, for example, as shown in FIG.
Obtained by spinning the three components from a nozzle having the structure shown in (1). The resulting fiber may be monofilament or multifilament. Preferably it is 10 to 200 denier yarn, more preferably 25 to 100 denier.
It is a denier multifilament.

Although the obtained spun yarn can be used as it is, it is preferable to perform a heat treatment in order to further exert the effects of the present invention. By performing the heat treatment, the melt-anisotropic aromatic polyester undergoes solid-phase polymerization, so that the melting point can be increased and the strength, elastic modulus, and heat resistance can be improved.

The heat treatment can be performed in an atmosphere of an inert gas such as nitrogen, in an atmosphere of an active gas containing oxygen such as air, or under reduced pressure. The heat treatment atmosphere is preferably a low humidity gas containing no moisture. The temperature is preferably lower than the melting point of the sheath component, but may be higher than the melting point of the sheath component as long as no sticking occurs.

The heat treatment raises the melting point of the melt-anisotropic aromatic polyester and significantly improves the dimensional stability against heat, but does not change the heat resistance behavior of the flexible polymer.

In the present invention, since the melt-anisotropic aromatic polyester is not exposed on the fiber surface during weaving, fibrillation peculiar to the melt-anisotropic aromatic polyester does not occur. For this reason, it is possible to fabricate thin fabrics, which has been difficult in the past.

The base fabric of the present invention is characterized in that sea components are stuck or fused at intersections of the fabric. Since the intersections are glued or fused, the core fibers having high strength and high elastic modulus are firmly fixed. Further, the glue or fusion component is reinforced with islands of high strength, high modulus fibrils. For this reason, it is a base fabric that has never existed before and has a high strength and a high elastic modulus and a remarkably small dimensional change.

The woven product or a method of sticking or fusing intersections of knitted fabric can be carried out by known methods. That is,
A hot press method, a hot roll method, a calender roll method, or the like is employed. Naturally, the temperature and the pressure are important parameters, and the conditions are set according to the target thickness and the opening ratio of the base cloth.

The main object of the present invention is to provide an unprecedented thin base cloth having high strength, high elastic modulus and low dimensional change. That is, the thickness is 50 to 10 μm
m, more preferably 40 to 10 μm.

The aperture ratio referred to in the present invention is a value obtained by taking a 200-fold photograph of the base fabric with a scanning electron microscope and calculating the ratio from an enlarged photograph including 20 openings. The aperture ratio is preferably 30% or less. If it exceeds 30%, it will not be a high-strength base fabric aimed at by the present invention.

The role of the opening in the present invention is to integrate the matrix resin and the base cloth when the resin is impregnated.

In the present invention, the base fabric having an aperture ratio of 0 (zero) is a film-like material made of a reinforced and knitted fabric made of high-strength and high-modulus fibers and made of a reinforced flexible resin.
This product does not have the direction of physical properties found in ordinary films, and exhibits outstanding strength and heat stability. This can be used for, for example, a flexible printed circuit board without impregnation with a resin. Depending on the core-sheath ratio, the sea-island ratio, and the selection of the polymer, rigidity can be provided, and it can be used for a multilayer IC substrate.

The base fabric of the present invention is a base fabric for a printed circuit board,
It can be used as a prepreg base fabric, a high-strength film material, or a high-strength sheet (film).

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

Example 1 A melt-anisotropic aromatic polyester (M) in which the structural unit as the core component (X) is the chemical formula (4) and the HNA component in the chemical formula 2 is 27 mol%
P = 280 ° C., MV = 420 poise) was used. As the sea component (A) in the sheath component (Y), PPS (MP = 2
81 ° C., MV = 1100 poise), and the same melt anisotropic polyester as the core component (X) was used as the island component (B). Using such a polymer, a nozzle hole having a structure of FIG.
It was spun at 20 ° C. The discharge rate was set so that the core-sheath component ratio was 0.5 and the sea-island ratio in the sheath component was 0.25. The resulting fiber was 50 denier / 8 filament.
This is heated in a nitrogen atmosphere at a temperature of 180 ° C to 265 ° C.
Until 25 hours. The resulting fiber had a strength of 14.3 g / d and an elongation of 4.1%. The filament was used to make a plain weave of 40 lines / inch. The weaving was good and there was no trouble. This was calendered at 150 ° C. The performance of the obtained base fabric is shown below. Weight: 26 g / m ² Thickness: 24 μm Opening ratio: 19% Strong (vertical direction): 65 kg / 5 cm (lateral direction): 63 kg / 5 cm Linear expansion coefficient at 200 ° C. (vertical direction): −5.95 × 10 ⁻⁵ / ° C. (Horizontal direction): −4.3 × 10 ⁻⁵ / ° C. As described above, the base fabric of this example is a low-weight, ultra-thin, and high-strength base fabric. It shows excellent dimensional stability.

Example 2 PEN (MP = 275 ° C., MV = 1500 pois) as the sea component (A) in the sheath component
Except for using e), a base fabric having the following performance was obtained in substantially the same manner as in Example 1. Weight: 28 g / m ² Thickness: 22 μm Opening ratio: 15% Strength (vertical direction): 68 kg / 5 cm (lateral direction): 63 g / 5 cm The linear expansion coefficient at 200 ° C. (vertical direction): −3.2 × 10 ⁻⁵ / ° C (lateral direction): −5.2 × 10 ⁻⁵ / ° C. As described above, the base fabric also has a low basis weight, an ultra-thin thickness, high strength, and excellent dimensional stability. I have.

<< Example 3 >> A semi-aromatic polyamide PEN having n = 9 in the above formula as a sea component (A) as a sheath component.
(MP = 291 ° C., MV = 800 poise) except that a base fabric having the following performance was obtained in substantially the same manner as in Example 1. Weight: 25 g / m ² Thickness: 20 μm Opening ratio: 10% Strong (vertical direction): 65 kg / 5 cm (horizontal direction): 65 g / 5 cm The linear expansion coefficient at 200 ° C. (vertical direction): -8.8 × 10 ⁻⁵ / ° C. (Horizontal direction): −2.5 × 10 ⁻⁵ / ° C. The base fabric also has a low basis weight, a very thin thickness, a high strength, and excellent dimensional stability.

Example 4 The procedure of Example 1 was repeated except that the calendering temperature of the plain fabric was 220 ° C. The performance of the obtained base fabric is shown below. Weight: 24 g / m ² Thickness: 18 μm Opening ratio: 0% Strong (vertical direction): 62 kg / 5 cm (lateral direction): 60 kg / 5 cm Linear expansion coefficient at 200 ° C. (vertical direction): −2.2 × 10 ⁻⁵ / ° C. (Landscape direction): −1.3 × 10 ⁻⁵ / ° C. The base fabric of this example has a thickness of 18 μm and a strength of vertical and horizontal lengths of 60 k.
g / 5 cm or more, which is an unprecedented low-weight, ultra-thin, high-strength film-like material, and exhibits excellent dimensional stability.

Comparative Example 1 A base fabric was obtained in substantially the same manner as in Example 1, except that the sheath component was PPS only. Some sheath peeling occurred during weaving. In addition, the sheath component flowed due to the calendering treatment of the woven fabric, and the base fabric was partially uneven in thickness. The performance of this base fabric is shown below. Weight: 28 g / m ² Thickness: 31 μm Opening ratio: 33% Strong (vertical direction): 51 kg / 5 cm (lateral direction): 48 kg / 5 cm Linear expansion coefficient at 200 ° C. (vertical direction): -8.5 × 10 ⁻⁵ / ° C. (Horizontal direction): −24.3 × 10 ⁻⁵ / ° C. This base cloth does not become a base cloth having a uniform thickness, and does not have sufficient adhesion at fiber intersections and has dimensional stability. Somewhat unsatisfactory.

[0038]

As described above, the base fabric of the present invention is ultra-thin, has high strength and high dimensional stability, and is extremely preferable as a base fabric for a substrate used in the field of electronics. Of course, the base fabric is useful not only for the substrate but also as a high-strength film-like member or sheet member.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a composite spinneret used for producing the composite fiber of the present invention.

Continued on front page F term (reference) 4L041 AA07 BA04 BA05 BA16 BA21 BC17 BC20 BD01 BD03 BD14 BD20 CA07 CA10 DD01 DD05 DD14 4L048 AA19 AA20 AA24 AA29 AA44 AA48 AA49 AA51 AB07 AC00 AC09 AC18 BA01 BA02 CA00 CA05 CA15 DA43 EB

Claims (8)

[Claims] 1. A sea component (A) comprising a core component (X) comprising a melt-anisotropic aromatic polyester and a sheath component (Y) comprising a flexible polymer and a sea component (A) dispersed in the sea component (A). A base fabric comprising fibers composed of island components made of a melt anisotropic aromatic polyester (B), wherein sea components are stuck or fused at intersections of the fabrics. 2. The sea component (A) of the fiber according to claim 1,
The base cloth is polyphenylene sulfide. 3. The fiber according to claim 1, wherein the sea component (A).
Is polyethylene naphthalate. 4. The fiber according to claim 1, wherein the sea component (A).
Is a semi-aromatic polyamide. 5. The base fabric according to claim 1, wherein the absolute values of the linear expansion coefficients in the vertical and horizontal directions are both 1 × 10 ⁻⁴ or less. 6. The base fabric according to claim 1, wherein the opening ratio is 30% or less. 7. The base fabric according to claim 1, wherein the weight is 40 g / m ² or less. 8. The method according to claim 1, wherein the thickness is 10 to 50 μm.
m.