JP2022091687A - Lcp extruded film, lcp stretched film, insulating material for circuit board, and metal foil-clad laminate - Google Patents

Abstract

To provide a novel LCP extruded film that is sufficiently suppressed in the molecular orientation, internal strain or the like of a thermoplastic liquid crystal polymer and is also significantly suppressed in the anisotropy of dimensional change rates, as compared to the conventional art, and provide an LCP stretched film, an insulating material for circuit boards, and a metal foil-clad laminate including the same.SOLUTION: Provided is an LCP extruded film containing a thermoplastic liquid crystal polymer, having a thickness of 15 to 300 μm, inclusive. A degree of alignment α1 (%) including an exposed film surface S1 and a degree of alignment α2 (%) including a film surface S2 located at a depth of 5 μm from the film surface S1, exposed by etching the film surface S1 in the thickness direction, satisfy the relationship of -4.0≤[(α2-α1)/α1]×100≤0.0. A coefficient of linear expansion in the MD direction and the TD direction at 23 to 200°C, measured by the TMA method compliant with JIS K7197, ranges from -30 to 55 ppm/K.SELECTED DRAWING: Figure 1

Description

The present invention relates to an LCP extruded film, an LCP stretched film, an insulating material for a circuit board, a metal foil-clad laminate, and the like.

Conventionally, as an insulating material for a circuit board, a varnish-impregnated composite material is known in which a glass cloth is impregnated with a thermosetting resin such as an epoxy resin and a varnish containing an inorganic filler and a solvent, and then heat-press molded. However, this manufacturing method is inferior in productivity due to poor process margin during manufacturing, for example, from the viewpoint of resin flowability during varnish impregnation and curability during hot press molding. Further, the thermosetting resin easily absorbs moisture, and its size changes with the moisture absorption, so that the dimensional accuracy (heating dimensional accuracy) of the obtained varnish-impregnated composite material is inferior.

On the other hand, a liquid crystal polymer (LCP) is a polymer that exhibits liquid crystallinity in a molten state or a solution state. In particular, the thermotropic liquid crystal polymer, which exhibits liquid crystal properties in the molten state, can be extruded and has excellent properties such as high gas barrier properties, high film strength, high heat resistance, high insulation, low water absorption, and low dielectric properties in the high frequency range. It has the above-mentioned properties. Therefore, a film using a thermoplastic liquid crystal polymer is being studied for practical use in gas barrier film material applications, electronic material applications, and electrically insulating material applications.

However, when single-layer extrusion molding is actually performed, a thermoplastic liquid crystal polymer film having high industrial utility value due to the high degree of liquid crystal orientation of the thermoplastic liquid crystal polymer, that is, an excellent appearance and appearance. It has been found that it is difficult to obtain a thermoplastic liquid crystal polymer film having good surface flatness.

Therefore, for example, in Patent Document 1, a three-layer co-extruded die is used instead of the single-layer extruded die, and a total aromatic polyester-based thermoplastic liquid crystal polymer is used as an intermediate layer, and a polyolefin resin or a polycarbonate resin is simultaneously extruded as both outer layers. By forming a three-layer laminated film in which the intermediate layer is a thermoplastic liquid crystal polymer layer and both outer layers are thermoplastic resin layers, the thermoplastic resin layers of both outer layers are peeled off and the intermediate layer is taken out as a film. It is disclosed that a thermoplastic liquid crystal polymer film having excellent thickness accuracy and good appearance and surface flatness can be obtained.

Further, for example, in Patent Document 2, in the thermoplastic liquid crystal polymer film described in Patent Document 1, the strength in the TD direction (Transverse Direction) with respect to the MD direction (Machine Direction) cannot withstand practical use. It was found that the strength of the thermoplastic liquid crystal polymer film obtained by using the feed block type three-layer co-extrusion die instead of the multi-manifold type co-extrusion die in the TD direction and the MD direction (longitudinal direction). It is disclosed that the anisotropy of is alleviated.

Japanese Unexamined Patent Publication No. 63-31729 Japanese Unexamined Patent Publication No. 2-178016

Insulation materials for circuit boards using liquid crystal polymers are excellent in high-frequency characteristics and low dielectric properties, so they are flexible printed wiring boards (FPCs) and flexible in the 5th generation mobile communication systems (5G) and millimeter-wave radars that will be developed in the future. In recent years, it has been in the limelight as an insulating material for circuit boards such as printed wiring board laminates and fiber-reinforced flexible laminates.

It is said that the techniques described in Patent Documents 1 and 2 described above can realize a thermoplastic liquid crystal polymer film having excellent thickness accuracy and good appearance and surface flatness. However, in reality, although the occurrence of peeling of the skin layer and peeling of fibrillated fibers caused by the highly molecular orientation of the thermoplastic liquid crystal polymer on the film surface can be suppressed, the thermoplasticity described in Patent Documents 1 and 2 can be suppressed. As for the liquid crystal polymer film, the thermoplastic liquid crystal polymer is still highly molecularly oriented as a whole film, and it is not practically usable as an insulating material for a circuit board.

Specifically, in the use of insulating materials for circuit boards, a thermoplastic liquid crystal polymer film may be used as a metal foil-clad laminate by thermocompression bonding a metal foil such as copper foil on one side and / or both sides thereof. be. By pattern-etching the metal foil to form fine wiring or the like, a metal foil-clad laminate can be used as a material for a circuit board such as an electronic circuit board or a multilayer board. Therefore, the thermoplastic liquid crystal polymer film that supports the metal foil is required to have a high degree of dimensional stability. However, the thermoplastic liquid crystal polymer films described in Patent Documents 1 and 2 still have a large difference in the dimensional change rate in the TD direction and the MD direction after etching, and cannot meet the recent demand for application to ultrafine processing. rice field.

The present invention has been made in view of the above problems. An object of the present invention is a novel LCP extruded film in which the molecular orientation, internal strain, etc. of the thermoplastic liquid crystal polymer are sufficiently reduced, and the anisotropy of the dimensional change rate is significantly reduced as compared with the conventional film. It is an object of the present invention to provide an LCP stretched film, an insulating material for a circuit board, a metal foil-clad laminate, and the like.

As a result of diligent studies to solve the above problems, the present inventors have obtained an exposed film surface S1 in which the molecular orientation and internal strain of the thermoplastic liquid crystal polymer are alleviated not only on the film surface but also inside the film. The difference between the included degree of orientation α1 and the degree of orientation α2 including the film surface S2 located at a depth of 5 μm from the film surface S1 exposed by etching the film surface S1 in the thickness direction is small and the linear expansion coefficient is small. A new LCP extruded film was produced, and further, it was found that the anisotropy of the dimensional change rate was reduced as compared with the conventional one, and the present invention was completed.

That is, the present invention provides various specific embodiments shown below.
(1) An LCP extruded film containing a thermoplastic liquid crystal polymer and having a thickness of 15 μm or more and 300 μm or less, the orientation degree α1 (%) including the exposed film surface S1 and the film surface S1 being etched in the thickness direction. The degree of orientation α2 (%) including the film surface S2 located at a depth of 5 μm from the film surface S1 exposed by the treatment is -4.0 ≦ [(α2-α1) / α1] × 100 ≦ 0. An LCP extruded film that satisfies the relationship of 0 and has a linear expansion coefficient in the MD direction and the TD direction at 23 to 200 ° C. measured by the TMA method conforming to JIS K7197 in the range of -30 to 55 ppm / K.

(2) The LCP extruded film according to (1), wherein the linear expansion coefficient in the TD direction is 0 to 55 ppm / K.
(3) The LCP extruded film according to (1) or (2), which is the intermediate layer obtained by removing both outer layers from the outer layer, the intermediate layer, and the laminated extruded film having the outer layer.
(4) In the adhesion test by the cross-cut method based on JIS K5600-5-6, the film surface S1 does not have a skin layer on which the tape can be peeled off, according to any one of (1) to (3). The LCP extruded film of the description.

(5) The LCP extruded film according to any one of (1) to (4), wherein the degree of orientation α2 of the surface S2 is 37.7 (%) or less.
(6) The LCP extruded film according to any one of (1) to (5), wherein the degree of orientation α1 of the film surface S1 is 39.0 (%) or less.
(7) The LCP extruded film according to any one of (1) to (6), which further contains an inorganic filler.
(8) The LCP extruded film according to any one of (1) to (7), which is a T-die extruded film.

(9) Insulation for a circuit board comprising the LCP extruded film according to any one of (1) to (8) and a laminate having at least one woven fabric provided on one side and / or both sides of the LCP extruded film. material.
(10) A metal foil-clad laminate comprising the LCP extruded film according to any one of (1) to (8) and metal foils provided on one side and / or both sides of the LCP extruded film.
(11) A laminate having at least the LCP extruded film and the woven fabric according to any one of (1) to (8), and metal foils provided on one side and / or both sides of the laminate are provided. Metal leaf-clad laminate.

(12) An LCP stretched film comprising the stretched body of the LCP extruded film according to any one of (1) to (8).
(13) The LCP stretched film according to (12), wherein the stretched body has a total stretch ratio (MD direction × TD direction) of 1.3 to 2.5 times that of the LCP extruded film.

(14) An insulating material for a circuit board, comprising a laminate having at least the LCP stretched film according to (12) or (13) and a woven fabric provided on at least one surface of the LCP stretched film.
(15) A metal foil-clad laminate comprising the LCP stretched film according to (12) or (13) and metal foils provided on one side and / or both sides of the LCP stretched film.
(16) A metal foil-clad laminate comprising a laminate having at least the LCP stretched film and the woven fabric according to (12) or (13) and metal foils provided on one side and / or both sides of the laminate. ..

According to one aspect of the present invention, a novel LCP extruded film, an LCP stretched film, an insulating material for a circuit board, a metal leaf-clad laminate, etc. It can be realized. Further, according to one aspect of the present invention, a novel LCP extruded film, an LCP stretched film, an insulating material for a circuit board, a metal foil-clad laminate, and the like, which have a small dimensional change rate itself in the MD direction and the TD direction, are realized. be able to. Therefore, according to various aspects of the present invention, it is possible to realize a highly reliable product suitable for recent ultrafine processing.

It is a schematic cross-sectional view which shows the LCP extruded film of one Embodiment. It is a conceptual diagram which shows the calculation principle of the degree of orientation based on the area ratio of the orientation peak. It is a figure which shows the co-extrusion method of the LCP extrusion film of one Embodiment. It is a figure which shows the co-extrusion method of the LCP extrusion film of one Embodiment. It is a figure which shows the co-extrusion method of the LCP extrusion film of one Embodiment. It is a schematic cross-sectional view which shows the insulating material for a circuit board of one Embodiment. It is a schematic cross-sectional view which shows the metal foil-covered laminated board of one Embodiment. It is a schematic cross-sectional view which shows the metal foil-covered laminated board of one Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Unless otherwise specified, the positional relationship such as up, down, left, and right shall be based on the positional relationship shown in the drawings. Further, the dimensional ratios in the drawings are not limited to the ratios shown in the drawings. However, the following embodiments are examples for explaining the present invention, and the present invention is not limited thereto. That is, the present invention can be arbitrarily modified and implemented without departing from the gist thereof. In this specification, for example, the notation of the numerical range of "1 to 100" includes both the lower limit value "1" and the upper limit value "100". The same applies to the notation of other numerical ranges.

(LCP extruded film)
FIG. 1 is a schematic cross-sectional view showing a main part of the LCP extruded film 100 of the present embodiment. The LCP extruded film 100 of the present embodiment is obtained by extruding a resin composition containing a thermoplastic liquid crystal polymer into a film having a thickness of 15 μm or more and 300 μm or less.

As mentioned above, in the LCP extruded film of the prior art, the thermoplastic liquid crystal polymer is extremely molecular on the film surface, such as peeling of the skin layer and peeling of fibrillated fibers on the film surface (film surface S1). It was oriented. It is presumed that this is because the thermoplastic liquid crystal polymer is highly oriented on the surface of the extruded body as a result of receiving shear stress from the side surface of the device during extrusion. Then, it was confirmed that the extreme molecular orientation of the thermoplastic liquid crystal polymer on the film surface was relaxed by the improvement as in Patent Documents 1 and 2, but at the same time, the molecule of the thermoplastic liquid crystal polymer on the film surface was confirmed. It has been found from the findings of the present inventors that it is not possible to realize a material that can withstand the required performance as an insulating material for a circuit board only by controlling the orientation. That is, in order to realize an LCP extruded film in which the anisotropy of the dimensional change rate is reduced, it occurs not only in controlling the molecular orientation of the thermoplastic liquid crystal polymer on the film surface S1 but also inside the film (film surface S2). It is also necessary to control the molecular orientation of the thermoplastic liquid crystal polymer and reduce internal strain.

In the LCP extruded film 100 of the present embodiment, unlike the prior art, the molecular orientation and internal strain of the thermoplastic liquid crystal polymer are alleviated not only on the film surface (film surface S1) but also on the inside of the film (film surface S2). As a result, the anisotropy of the dimensional change rate is significantly reduced as compared with the conventional case. That is, the LCP extruded film 100 of the present embodiment has an orientation degree α1 (%) including the exposed film surface S1 and a depth of 5 μm from the film surface S1 exposed by etching the film surface S1 in the thickness direction. The degree of orientation α2 (%) including the film surface S2 located at is satisfied with the relationship of -4.0 ≦ [(α2-α1) / α1] × 100 ≦ 0.0, and TMA compliant with JIS K7197. It is characterized in that the linear expansion coefficient in the MD direction and the TD direction at 23 to 200 ° C. measured by the method is in the range of -30 to 55 ppm / K. Hereinafter, it will be described in more detail.

As the LCP extruded film 100, an extruded film such as a T-die extruded film is preferably used. The LCP extruded film 100 is an intermediate layer (core layer) of a three-layer coextruded film having a laminated structure in which a thermoplastic resin layer, a thermoplastic liquid crystal polymer layer, and a thermoplastic resin layer are arranged at least in this order. A thermoplastic liquid crystal polymer layer is also preferably used. In this case, by removing the thermoplastic resin layers of both outer layers of the three-layer coextruded film, it can be used as a single-layer thermoplastic liquid crystal polymer film (LCP extruded film 100). Extruded films of thermoplastic liquid crystal polymers can be manufactured at low cost and homogeneously as compared with woven fabrics and non-woven fabrics made of fibers of thermoplastic liquid crystal polymers.

As the thermoplastic liquid crystal polymer contained in the LCP extruded film 100, those known in the art can be used, and the type thereof is not particularly limited. The liquid crystal polymer is a polymer that forms an optically anisotropic molten phase, and examples thereof include thermotropic liquid crystal compounds. The properties of the anisotropic molten phase can be confirmed by a known method such as a polarization inspection method using an orthogonal polarizing element. More specifically, the confirmation of the anisotropic molten phase can be carried out by observing the sample placed on the Leitz hot stage at a magnification of 40 times under a nitrogen atmosphere using a Leitz polarizing microscope.

Specific examples of the thermoplastic liquid crystal polymer include a single amount of an aromatic or aliphatic dihydroxy compound, an aromatic or aliphatic dicarboxylic acid, an aromatic hydroxycarboxylic acid, an aromatic diamine, an aromatic hydroxyamine, an aromatic aminocarboxylic acid and the like. Examples thereof include those obtained by polycondensing the body, but the present invention is not particularly limited thereto. The thermoplastic liquid crystal polymer is preferably a copolymer. Specifically, an aromatic polyamide resin obtained by polycondensing monomers such as aromatic hydroxycarboxylic acid, aromatic diamine, and aromatic hydroxyamine; aromatic diol, aromatic carboxylic acid, aromatic hydroxycarboxylic acid, and the like. (Whole) aromatic polyester resin obtained by polycondensing the monomers of the above; and the like; but are not particularly limited thereto. These can be used alone or in any combination and ratio of two or more.

Thermoplastic liquid crystal polymers are generally classified into type I, type II, type III and the like from the viewpoint of heat distortion temperature (TDUL). The LCP extruded film 100 of the present embodiment can be suitably used regardless of the type of thermoplastic liquid crystal polymer, and may be appropriately selected and used according to the application application. For example, in an electronic circuit board application that is required to be applied to lead-free solder at about 230 to 260 ° C., a highly heat-resistant type I thermoplastic liquid crystal polymer having a TDUL of about 250 to 350 ° C. and a TDUL of about 240 to 250 ° C. A type II thermoplastic liquid crystal polymer having a relatively high heat resistance is preferably used.

Among these, (all) aromatic polyester resins having a thermotropic-type liquid crystal-like property and a melting point of 250 ° C. or higher, preferably a melting point of 280 ° C. to 380 ° C. are preferably used. As such an (whole) aromatic polyester resin, for example, a (whole) aromatic polyester resin that exhibits liquidity when melted, which is synthesized from a monomer such as an aromatic diol, an aromatic carboxylic acid, or a hydroxycarboxylic acid, is known. Has been done. Typical examples are a polycondensate of ethylene terephthalate and parahydroxybenzoic acid, a polycondensate of phenol and phthalic acid with parahydroxybenzoic acid, and 2,6-hydroxynaphthoic acid and parahydroxybenzoic acid. Examples thereof include polycondensates, but the present invention is not particularly limited thereto. As the (all) aromatic polyester resin, one kind may be used alone, or two or more kinds may be used in any combination and ratio. Depending on the required performance, an all-aromatic polyester resin having a relatively high melting point or high thermal deformation temperature and high heat resistance may be used, or an aromatic polyester having a relatively low melting point or low thermal deformation temperature and excellent molding processability. Resin can be used.

In a preferred embodiment, 6-hydroxy-2-naphthoic acid and a derivative thereof (hereinafter, may be simply referred to as "monomer component A") are used as a basic structure, and parahydroxybenzoic acid, terephthalic acid, isophthalic acid, and the like. One or more selected from the group consisting of 6-naphthalenedicarboxylic acid, 4,4'-biphenol, bisphenol A, hydroquinone, 4,4-dihydroxybiphenol, ethylene terephthalate and derivatives thereof is a monomer component (hereinafter, simply " It may be referred to as "monomer component B"), and examples thereof include (all) aromatic polyester resins having at least. In such (whole) aromatic polyester resin, the linear lines of molecules are regularly arranged in a molten state to form an anisotropic molten phase, which typically exhibits thermotropic type liquid crystal-like properties, and has mechanical properties. It has excellent basic performance in electrical characteristics, high frequency characteristics, heat resistance, hygroscopicity, etc.

Further, the (all) aromatic polyester resin of the preferred embodiment described above can have any configuration as long as it has a monomer component A and a monomer component B as essential units. For example, it may have two or more kinds of monomer components A or may have three or more kinds of monomer components A. Further, the (all) aromatic polyester resin of the preferred embodiment described above contains other monomer components (hereinafter, may be simply referred to as “monomer component C”) other than the monomer component A and the monomer component B. You may be doing it. That is, even if the (all) aromatic polyester resin of the above-mentioned preferred embodiment is a polycondensate having a binary system or more composed of only the monomer component A and the monomer component B, the monomer component A, the monomer component B, and the monomer component It may be a polycondensate of a monomer component of a ternary system or more composed of C. Other monomer components include those other than the above-mentioned monomer component A and monomer component B, specifically, aromatic or aliphatic dihydroxy compounds and derivatives thereof; aromatic or aliphatic dicarboxylic acids and derivatives thereof; aromatic hydroxycarboxylic acids. Acids and derivatives thereof; aromatic diamines, aromatic hydroxyamines or aromatic aminocarboxylic acids and derivatives thereof; and the like; but are not particularly limited thereto. As the other monomer components, one kind may be used alone, or two or more kinds may be used in any combination and ratio.

In the present specification, the "derivative" is a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom) and an alkyl group having 1 to 5 carbon atoms (for example, methyl) as a part of the above-mentioned monomer component. Group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, etc.), aryl group such as phenyl group, hydroxyl group, alkoxy group having 1 to 5 carbon atoms (For example, methoxy group, ethoxy group, etc.), carbonyl group, —O—, —S—, —CH _2- , or other modifying group introduced (hereinafter referred to as “monomer component having a substituent””. There is.). Here, the "derivative" may be an ester-forming monomer such as an acylated product, an ester derivative, or an acid halide of the monomer components A and B which may have the above-mentioned modifying group.

In a particularly preferred embodiment, a binary polycondensate of parahydroxybenzoic acid and its derivative and 6-hydroxy-2-naphthoic acid and its derivative; parahydroxybenzoic acid and its derivative and 6-hydroxy-2-naphthoe A ternary or higher polycondensate of an acid and its derivative and monomer component C; parahydroxybenzoic acid and its derivative and 6-hydroxy-2-naphthoic acid and its derivative and terephthalic acid, isophthalic acid, 6-naphthalenedicarboxylic acid , 4,4'-Bisphenol A, Hydroquinone, 4,4-dihydroxybiphenol, ethylene terephthalate and one or more polycondensates of one or more selected from the group consisting of derivatives thereof; parahydroxy Saprophytic acid and its derivatives and 6-hydroxy-2-naphthoic acid and its derivatives and terephthalic acid, isophthalic acid, 6-naphthalenedicarboxylic acid, 4,4'-biphenol, bisphenol A, hydroquinone, 4,4-dihydroxybiphenol, ethylene Examples thereof include a quaternary or higher polycondensate composed of one or more selected from the group consisting of terephthalates and derivatives thereof and one or more monomer components C. These can be obtained as having a relatively low melting point with respect to, for example, a homopolymer of parahydroxybenzoic acid, and therefore, a thermoplastic liquid crystal polymer using these can be obtained at the time of thermocompression bonding to an adherend. It has excellent moldability.

The melting point of the (all) aromatic polyester resin is lowered to improve the molding processability when the LCP extruded film 100 is heat-bonded to the adherend, or the peel strength is high when the LCP extruded film 100 is heat-bonded to the metal foil. The content ratio of the monomer component A to the (total) aromatic polyester resin in terms of molar ratio is preferably 10 mol% or more and 90 mol% or less, more preferably 30 mol% or more and 85 mol% or less. More preferably, it is 50 mol% or more and 80 mol% or less. Similarly, the content ratio of the monomer component B to the (total) aromatic polyester resin in terms of molar ratio is preferably 10 mol% or more and 90 mol% or less, more preferably 15 mol% or more and 70 mol% or less, and more preferably 20 mol% or more. More preferably, it is 50 mol% or less. Further, the content ratio of the monomer component C which may be contained in the (total) aromatic polyester resin is preferably 10 mol% or less, more preferably 8 mol% or less, still more preferably 5 mol% or less in terms of molar ratio. Particularly preferably, it is 3 mol% or less.

A known method can be applied to the method for synthesizing the (all) aromatic polyester resin, and the method is not particularly limited. A known polycondensation method for forming an ester bond with the above-mentioned monomer components, for example, a melt polymerization method, a melt acidlysis method, a slurry polymerization method, or the like can be applied. When applying these polymerization methods, an acylation or acetylation step may be performed according to a conventional method.

The LCP extruded film 100 may further contain an inorganic filler. By containing an inorganic filler, an LCP extruded film 100 having a reduced coefficient of linear expansion can be realized. Specifically, linear expansion in the MD direction, the TD direction, and the ZD direction (Z-axis Direction). It is easy to obtain an LCP extruded film 100 having reduced coefficient anisotropy. Such an LCP extruded film 100 is particularly useful, for example, in rigid substrate applications where multi-layer lamination is required.

As the inorganic filler, those known in the art can be used, and the type thereof is not particularly limited. For example, kaolin, calcined kaolin, calcined clay, unfired clay, silica (eg natural silica, molten silica, amorphous silica, hollow silica, wet silica, synthetic silica, aerodil, etc.), aluminum compounds (eg boehmite, aluminum hydroxide, alumina, etc.) Hydrotalcite, aluminum borate, aluminum nitride, etc.), magnesium compounds (eg, magnesium aluminometasilicate, magnesium carbonate, magnesium oxide, magnesium hydroxide, etc.), calcium compounds (eg, calcium carbonate, calcium hydroxide, calcium sulfate, etc.) Calcium sulfite, calcium borate, etc.), molybdenum compounds (eg, molybdenum oxide, zinc molybdate, etc.), talc (eg, natural talc, calcined talc, etc.), mica (mica), titanium oxide, zinc oxide, zirconium oxide, barium sulfate, Examples thereof include zinc borate, barium metaborate, sodium borate, boron nitride, aggregated boron nitride, silicon nitride, carbon nitride, strontium titanate, barium titanate, and sulfates such as zinc tintate. Not limited. These can be used alone or in combination of two or more. Among these, silica is preferable from the viewpoint of dielectric properties and the like.

Further, the inorganic filler used here may be one that has been subjected to a surface treatment known in the art. The surface treatment can improve moisture resistance, adhesive strength, dispersibility and the like. Examples of the surface treatment agent include, but are not limited to, a silane coupling agent, a titanate coupling agent, a sulfonic acid ester, a carboxylic acid ester, and a phosphoric acid ester.

The median diameter (d50) of the inorganic filler can be appropriately set according to the required performance and is not particularly limited. The d50 of the inorganic filler is preferably 0.01 μm or more and 50 μm or less, more preferably 0.03 μm or more and 50 μm or less, and further preferably 0. It is 1 μm or more and 50 μm or less. In the present specification, the median diameter (d50) of the inorganic filler is measured on a volume basis by a laser diffraction / scattering method using a laser diffraction / scattering type particle size distribution measuring device (LA-500 manufactured by HORIBA, Ltd.). Means the value to be.

The content of the inorganic filler can be appropriately set according to the required performance in consideration of the blending balance with other essential components and optional components, and is not particularly limited. From the viewpoint of kneadability and handleability at the time of preparation, the effect of reducing the coefficient of linear expansion, etc., the content of the inorganic filler is 1% by mass or more and 45% by mass or less in total in terms of solid content with respect to the total amount of the LCP extruded film 100. It is preferable, more preferably 3% by mass or more and 40% by mass or less in total, and further preferably 5% by mass or more and 35% by mass or less in total.

The LCP extruded film 100 is a resin component other than the above-mentioned thermoplastic liquid crystal polymer (hereinafter, may be simply referred to as “other resin component”), for example, thermosetting, as long as the effect of the present invention is not excessively impaired. It may contain a sex resin, a thermoplastic resin, or the like. Further, the LCP extruded film 100 is an additive known in the art, for example, a higher fatty acid having 10 to 25 carbon atoms, a higher fatty acid ester, a higher fatty acid amide, or a higher fatty acid metal salt, as long as the effect of the present invention is not excessively impaired. , Polysiloxane, Fluororesin and other mold release improvers; Dyes, pigments and other colorants; Organic fillers; Antioxidants; Heat stabilizers; Light stabilizers; UV absorbers; Flame retardants; Antistatic agents; Surfactants Agent; rust preventive agent; antifoaming agent; fluorescent agent and the like may be contained. Each of these additives may be used alone or in combination of two or more. These additives can be included in the molten resin composition prepared at the time of molding the LCP extruded film 100. The contents of these resin components and additives are not particularly limited, but are preferably 0.01 to 10% by mass, respectively, with respect to the total amount of the LCP extruded film 100 from the viewpoint of moldability, thermal stability, and the like. It is preferably 0.1 to 7% by mass, more preferably 0.5 to 5% by mass, respectively.

The thickness of the LCP extruded film 100 can be appropriately set according to the requirements and is not particularly limited. Considering the handleability and productivity at the time of extrusion molding, it is preferably 15 μm or more and 300 μm or less, more preferably 18 μm or more and 250 μm or less, and further preferably 20 μm or more and 200 μm or less.

The LCP extruded film 100 of the present embodiment has the desired dimensions by alleviating the molecular orientation and internal strain of the thermoplastic liquid crystal polymer not only on the film surface (film surface S1) but also on the inside of the film (film surface S2). From the viewpoint of reducing the anisotropy of the rate of change, the degree of orientation α1 including the film surface S1 and the degree of orientation α2 including the film surface S2 are adjusted so as to satisfy the following relationship.
It is preferably -4.0 ≦ [(α2-α1) / α1] × 100 ≦ 0.0.
More preferably, −3.0 ≦ [(α2-α1) / α1] × 100 ≦ 0.0.
More preferably, −2.0 ≦ [(α2-α1) / α1] × 100 ≦ 0.0.

Here, the film surface S1 is the outermost surface of the LCP extruded film 100 of the present embodiment, and is an exposed surface exposed outward. The degree of orientation including the film surface S1 (degree of orientation α1) is preferably 39.0% or less, more preferably 38.5% or less, still more preferably 38.0% or less. On the other hand, the film surface S2 is a surface newly exposed by etching the film surface S1 of the LCP extruded film 100 of the present embodiment in the thickness direction, and in FIG. 1, a virtual surface located at a depth of 5 μm from the film surface S1. It is represented by a broken line as a surface. The degree of orientation including the film surface S2 (degree of orientation α2) is preferably 37.7% or less, more preferably 37.5% or less, still more preferably 37.3% or less. Further, the depth at which the film surface S2 is located does not have to be exactly 5 μm from the film surface S1 in consideration of dissolution error during etching, and may be 5.0 μm or more from the film surface S1. Further, the etching treatment conditions for producing the film surface S2 are not particularly limited, but from the viewpoint of ensuring the objectivity between the measurement data, the conditions described in Examples described later shall be followed.

In the present specification, the orientation degrees α1 and α2 (%) including the film surfaces S1 and S2 of the LCP extruded film 100 are subjected to X-ray diffraction measurement by a transmission method using an X-ray diffractometer, and the obtained diffraction is obtained. It means a value calculated from the following formula based on the area ratio of the orientation peak in the intensity distribution curve. Generally, in the case of a measurement target with a small degree of orientation (%), a broad diffraction peak with a small peak intensity is observed in X-ray diffraction measurement, so a calculation method based on the half-value width of the orientation peak has high measurement accuracy. Cannot be guaranteed. Therefore, in the present specification, the degree of orientation α1 and α2 (%) including the film surfaces S1 and S2 are calculated by a calculation method based on the area ratio of the orientation peak instead of the half width of the orientation peak. Specifically, as shown in FIG. 2 and Equation 1, as a calculation method based on the area ratio of the orientation peak, the peak intensity (orientation component) is measured by the 2θ / θ scan, and the orientation angle direction is measured by the β scan. The intensity from 0 ° to 360 ° is measured to obtain the intensity distribution in the azimuth angle direction (base strength (isotropic component)), and the area occupied by the orientation component excluding the area of the base isotropic component. Is calculated as the degree of orientation (%) as a percentage of the total area (area of the orientation component + area of the isotropic component).

On the other hand, in the LCP extruded film 100 of the present embodiment, not only the molecular orientation of the thermoplastic liquid crystal polymer represented by the above-mentioned degree of orientation but also the molecules of the thermoplastic liquid crystal polymer represented by the linear expansion coefficients in the MD direction and the TD direction. The orientation is also sufficiently reduced. As described above, in the LCP extruded films described in Patent Documents 1 and 2 of the prior art, the molecular orientation of the thermoplastic liquid crystal polymer is slightly aligned by being protected by the thermoplastic resin layers of both outer layers at the time of coextrusion of the three layers. It can be seen that the anisotropy of the strength of the obtained thermoplastic liquid crystal polymer film in the MD direction and the TD direction is relaxed. However, in reality, the LCP extruded films described in Patent Documents 1 and 2 have a stable linear expansion coefficient of about -20 ppm / K in the MD direction, whereas they are in the TD direction. The coefficient of linear expansion exceeds 55 ppm, and sometimes reaches about 100 ppm / K. As is clear from this, in the LCP extruded films described in Patent Documents 1 and 2 of the prior art, the molecular orientation of the thermoplastic liquid crystal polymer still remains largely in the film as a whole, or the internal strain and the like are large. It is easy to understand that it remains. Therefore, it is necessary to control the molecular orientation, internal strain, and the like of the thermoplastic liquid crystal polymer of the LCP extruded film 100 as a whole film by the combination of the degree of orientation including the film surface and the coefficient of linear expansion described above.

The LCP extruded film 100 of the present embodiment has a linear expansion coefficient (CTE, α2, 23 to 200 ° C.) in the MD direction and the TD direction in the range of −30 to 55 ppm / K. The LCP extruded film 100 having a linear expansion coefficient within such a range is in a state where internal strain and the like are sufficiently reduced, and the anisotropy of the dimensional change rate is smaller than that in the case where it is not, and the dimensional change is small. It can be an LCP extruded film with a sufficiently small absolute value of rate. The linear expansion coefficient (CTE, α2, 23 to 200 ° C.) of the LCP extruded film 100 of the present embodiment in the MD direction is in the range of -30 to 10 ppm / K from the viewpoint of further improving the adhesion to the metal foil. It is preferably in the range of -25 to 5 ppm / K, more preferably in the range of -20 to 0 ppm / K, and even more preferably in the range of -20 to 0 ppm / K. Further, the linear expansion coefficient (CTE, α2, 23 to 200 ° C.) of the LCP extruded film 100 of the present embodiment in the TD direction is 0 to 55 ppm / K from the viewpoint of further improving the adhesion to the metal foil. It is preferably in the range, more preferably in the range of 0 to 50 ppm / K, and even more preferably in the range of 0 to 45 ppm / K. In the present specification, the coefficient of linear expansion (CTE, α2, 23 to 200 ° C.) means a value in a temperature interval of 23 to 200 ° C. measured by the TMA method based on JIS K7197. In addition, other detailed measurement conditions shall be in accordance with the conditions described in Examples described later.

In the present specification, the coefficient of linear expansion is measured by the TMA method based on JIS K7197, and the average coefficient of linear expansion means the average value of the coefficient of linear expansion at 23 to 200 ° C. measured by the same method. .. The coefficient of linear expansion measured here is such that the LCP extruded film 100 is heated at a heating rate of 5 ° C./min (1st heating) and then cooled to the measured ambient temperature (23 ° C.) in order to see the value obtained by eliminating the thermal history. It means the value when (1st cooling) is performed and then the second heating (2nd heating) is performed at a heating rate of 5 ° C./min. In addition, other detailed measurement conditions shall be in accordance with the conditions described in Examples described later.

On the other hand, the dielectric property of the LCP extruded film 100 of the present embodiment can be appropriately set according to the desired performance and is not particularly limited. From the viewpoint of obtaining higher dielectric properties, the relative permittivity ε _r (36 GHz) is preferably 3.0 or more and 3.7 or less, and more preferably 3.0 to 3.5. Similarly, the dielectric loss tangent tan δ (36 GHz) is preferably 0.0010 or more and 0.0050 or less, and more preferably 0.0010 or more and 0.0045 or less. In the present specification, the relative permittivity ε _r (36 GHz) and the dielectric loss tangent tan δ (36 GHz) mean the values at 36 GHz measured by the cavity resonator contact method according to JIS K6471. In addition, other detailed measurement conditions shall be in accordance with the conditions described in Examples described later.

(Manufacturing method of LCP extruded film)
The LCP extruded film 100 of the present embodiment can be obtained by extruding a resin composition containing the above-mentioned thermoplastic liquid crystal polymer and optional components such as an inorganic filler and other resin components to a predetermined thickness. Can be done. As the extrusion method, various known methods can be applied, and the type thereof is not particularly limited. For example, a T-die method or an inflation method; for example, a multi-manifold co-extrusion method or a feed block co-extrusion method; for example, a multi-layer co-extrusion method such as a two-layer co-extrusion method or a three-layer co-extrusion method; can do.

Among these, from the viewpoint of ease of controlling the molecular orientation of the thermoplastic liquid crystal polymer on the film surface (film surface S1) and inside the film (film surface S2), as a preferred embodiment, the above-mentioned resin composition is used as T. It is extruded from the T-die by an extrusion molding method using a die (hereinafter, may be simply referred to as "T-die extrusion method") to form a film, and then cooled, crimped, and pressed as necessary. A method of obtaining a predetermined LCP extruded film 100 by heat treatment or the like can be mentioned. Specifically, the resin composition A for the first surface layer containing the thermoplastic resin, the resin composition B for the intermediate layer containing the thermoplastic liquid crystal polymer, and the resin composition C for the second surface layer containing the thermoplastic resin. Are prepared, and these are co-extruded from the co-extrusion die of the extruder to extrude the co-extruded melt having a three-layer structure to form the LCP extruded film 100 as the thermoplastic liquid crystal polymer layer of the intermediate layer. The extrusion method is preferable. According to such coextrusion molding, the molecular orientation of the thermoplastic liquid crystal polymer in the thermoplastic liquid crystal polymer layer of the intermediate layer is relaxed by being protected by the thermoplastic resin layers of both outer layers. Hereinafter, a preferred embodiment of the method for producing the LCP extruded film 100 of the present embodiment will be described in detail.

3 to 5 are views showing a preferred embodiment of the method for producing the LCP extruded film 100 of the present embodiment described above. Here, the above-mentioned resin composition B containing the above-mentioned thermoplastic liquid crystal polymer and, if necessary, an optional component such as an inorganic filler and other resin components is melt-extruded into a film from the T-die of the extruder. At this time, by co-extruding the resin compositions A and C containing the thermoplastic resin on both sides of the film-shaped molten extruded product, the first outer layer (peeling layer) containing the thermoplastic resin and the thermoplastic liquid crystal polymer can be obtained. A coextruded melt (three-layer laminated film) having a predetermined thickness and having an intermediate layer (LCP layer) containing the mixture and a second outer layer (release layer) containing the thermoplastic resin is produced. The coextruded melt is drawn out on a take-up roll and sent to a cooling roll and a crimping roll. After that, the first outer layer and the second outer layer are peeled off from the intermediate layer, and the thermoplastic resin layer of both outer layers and the thermoplastic liquid crystal polymer layer (LCP extruded film 100) of the intermediate layer are respectively wound on the take-up roll. ..

The preparation of the resin composition B containing the above-mentioned thermoplastic liquid crystal polymer may be carried out according to a conventional method, and is not particularly limited. Each of the above-mentioned components can be manufactured and processed by a known method such as kneading, melt kneading, granulation, extrusion molding, pressing or injection molding. When performing melt kneading, a kneading device such as a generally used uniaxial or biaxial extruder or various kneaders can be used. When supplying each component to these melt-kneading devices, a liquid crystal polymer, other resin components, inorganic fillers, additives and the like may be dry-blended in advance using a mixing device such as a tumbler or a Henschel mixer. At the time of melt-kneading, the cylinder set temperature of the kneading device may be appropriately set and is not particularly limited, but is generally preferably in the range of the melting point of the liquid crystal polymer or higher and 360 ° C. or lower, and more preferably the melting point of the liquid crystal polymer + 10 ° C. or higher and 360 ° C. or higher. It is below ° C.

The resin compositions A and C containing the thermoplastic resin may also be prepared according to a conventional method, and are not particularly limited. Examples of the thermoplastic resin include polyethylene, polypropylene, polymethylpentene, polyolefin resins such as ethylene-α-olefin copolymers, acrylic resins such as PMMA, polyamide resins, and acrylonitrile-butadiene-styrene copolymers (ABS). Resin), polystyrene (PS), polyvinyl chloride, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC), polyether ether ketone (PEEK), polyphenyl sulfide (PPS) and the like. It is not particularly limited to these. When it is made into a coextruded melt, it functions effectively as a release layer regardless of whether it is a polar resin such as polycarbonate or a non-polar resin such as polymethylpentene. These thermoplastic resins may be blended with other resin components which may be contained in the above-mentioned LCP extruded film 100 or optional components such as an inorganic filler. The resin composition A and the resin composition C may have the same resin composition or different resin compositions, and may have different thermoplastic properties even if they contain the same thermoplastic resin. It may contain a resin. The resin composition containing the thermoplastic resin can be produced and processed by a known method such as kneading, melt kneading, granulation, extrusion molding, pressing or injection molding. When performing melt kneading, a kneading device such as a generally used uniaxial or biaxial extruder or various kneaders can be used. When supplying each component to these melt-kneading devices, the thermoplastic resin, other resin components, inorganic fillers, additives and the like may be dry-blended in advance using a mixing device such as a tumbler or a Henshell mixer. At the time of melt-kneading, the cylinder set temperature of the kneading device may be appropriately set at a temperature or lower at which the thermoplastic resin does not deteriorate due to thermal decomposition, and is not particularly limited. The melting point of the thermoplastic resin is + 10 ° C or higher.

The setting conditions for coextrusion may be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the target extruded film, and the like, and are not particularly limited. For example, the set temperature of the cylinder of the extruder may be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the desired extruded film, and the like, and is not particularly limited, but is preferably 230 to 360 ° C. More preferably, it is 280 to 350 ° C.

Further, for example, the die width (mm) of the T die may be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the desired extruded film, and the like, and is not particularly limited, but is general. The thickness is preferably 200 to 2000 mm, more preferably 400 to 1500 mm.

Further, for example, the lip opening (mm) of the T-die may be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the desired extruded film, and the like, and is not particularly limited, but is generally used. It is preferably 0.1 to 3.0 (mm), more preferably 0.2 to 2.0 (mm).

Then, for example, the shear rate (sec ^-1 ) of the lip wall surface of the T-die may be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the desired extruded film, and the like, and is particularly limited. However, it is generally preferably 100 to 1500 (sec ^-1 ), more preferably 150 to 1000 (sec ^-1 ).

Similarly, the total discharge amount (mm ³ / sec) of the resin composition of the T-die may be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the target extruded film, and the like. Although not particularly limited, it is generally preferably 500 to 15000 (mm ³ / sec), more preferably 1500 to 10000 (mm ³ / sec).

On the other hand, the melt viscosity (Pa · sec) of the thermoplastic liquid crystal polymer may also be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the desired extruded film, and the like, and is not particularly limited. Generally, it is preferably 10 to 300 (Pa · sec), more preferably 20 to 250 (Pa · sec). The melt viscosity (Pa · sec) of the thermoplastic liquid crystal polymer conforms to JIS K7199, and uses Capillograph 1D (manufactured by Toyo Seiki Seisakusho Co., Ltd.) to have a cylinder length of 10.00 mm, a cylinder diameter of 1.00 mm, and a barrel diameter. It means a value measured under the condition of 9.55 mm and the condition at the time of manufacturing the LCP extruded film 100 (die temperature and shear rate of the lip wall surface).

Similarly, the take-up speed (mm / sec) of the co-extruded film may be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the target extruded film, and the like, and is not particularly limited. Generally, it is preferably 15 to 1000 (mm / sec), more preferably 20 to 500 (mm / sec).

Here, from the viewpoint of reducing the molecular orientation of the thermoplastic liquid crystal polymer during coextrusion in the MD direction, it is desirable that the shear stress (kPa) during coextrusion is low. When the shear stress during coextrusion is large, the thermoplastic liquid crystal polymer tends to be highly oriented in the MD direction, and internal strain tends to remain. When the shear stress during coextrusion is small, the film surface (film surface) tends to be high. In both S1) and the inside of the film (film surface S2), the molecular orientation of the thermoplastic liquid crystal polymer tends to be reduced, and internal strain tends to be difficult to remain. The shear stress (kPa) during coextrusion is a value expressed by the product of the shear rate (sec ^-1 ) of the lip wall surface and the melt viscosity (Pa · sec) of the thermoplastic liquid crystal polymer, and the shear rate is , A value calculated based on the total discharge amount of the resin composition at the time of coextrusion, the die width, and the lip opening degree. Therefore, the shear stress during coextrusion can be controlled by adjusting each of these values. Specifically, the shear stress at the time of coextrusion is preferably 40 kPa or less, more preferably 38 kPa or less, and further preferably 36 kPa or less. The lower limit is not particularly limited, but is preferably 5 kPa or more, more preferably 10 kPa or more, in consideration of productivity and the like.

Further, from the viewpoint of reducing the molecular orientation of the thermoplastic liquid crystal polymer in the MD direction during coextrusion, it is desirable that the drawdown ratio during coextrusion is low. When the drawdown ratio during coextrusion is large, the thermoplastic liquid crystal polymer tends to be highly oriented in the MD direction, and internal strain tends to remain. When the drawdown ratio during coextrusion is small, the film surface ( The molecular orientation of the thermoplastic liquid crystal polymer is likely to be reduced and internal strain is unlikely to remain on both the film surface S1) and the film interior (film surface S2). The drawdown ratio is a value expressed by the take-up speed (mm / sec) / the flow rate of the thermoplastic liquid crystal polymer (mm / sec), and the flow rate of the thermoplastic liquid crystal polymer is the flow rate of the resin composition at the time of coextrusion. It is a value calculated based on the total discharge amount, the die width, and the lip opening. Therefore, the drawdown ratio during coextrusion can be controlled by adjusting each of these values. Specifically, the drawdown ratio at the time of coextrusion is preferably 3.5 or less, more preferably 3.3 or less, still more preferably 3.1 or less. The lower limit is not particularly limited, but is preferably 1.0 or more, more preferably 1.2 or more, in consideration of productivity and the like.

The thickness of the obtained LCP extruded film 100 can be appropriately set according to the requirements and is not particularly limited. Considering the handleability and productivity at the time of extrusion molding, it is preferably 15 μm or more and 300 μm or less, more preferably 18 μm or more and 250 μm or less, and further preferably 20 μm or more and 200 μm or less.

The melting point (melting temperature) of the obtained LCP extruded film 100 is not particularly limited, but from the viewpoint of heat resistance and processability of the film, the melting point (melting temperature) is preferably 200 to 400 ° C., particularly a metal foil. From the viewpoint of enhancing the heat pressure-bonding property to the metal, the temperature is preferably 250 to 360 ° C, more preferably 260 to 355 ° C, still more preferably 270 to 350 ° C, and particularly preferably 275 to 345 ° C. In the present specification, the melting point of the LCP extruded film 100 is a DSC8500 (manufactured by PerkinElmer), and the extruded film is heated at 20 ° C./min in a temperature interval of 30 to 400 ° C. in order to see the value obtained by eliminating the thermal history. Differences when heating (1st heating) at the heating rate of 1st heating, cooling at a temperature lowering rate of 50 ° C./min (1st cooling), and then heating at a heating rate of 20 ° C./min for the second time (2nd heating). It means the melting peak temperature in the scanning calorimetry (DSC). For others, the measurement conditions described in Examples described later shall be followed.

The extruded LCP extruded film 100 can be used as it is, but the orientation (anisotropic) can be further reduced or the internal strain can be further reduced by further performing a pressure heating step as necessary. It can also be released, whereby the LCP extruded film 100 in which the anisotropy of the dimensional change rate is further reduced and the LCP extruded film 100 in which the absolute value of the dimensional change rate is smaller can be realized.

The heat-pressurizing treatment may be performed by a method known in the art, for example, a contact type heat treatment, a non-contact heat treatment, or the like, and the type thereof is not particularly limited. For example, heat can be set by using known equipment such as a non-contact heater, an oven, a blow device, a heat roll, a cooling roll, a heat press machine, and a double belt heat press machine. At this time, if necessary, a release film or a porous film known in the art can be arranged on the surface of the LCP extruded film 100 to perform heat treatment. Further, when this heat treatment is performed, from the viewpoint of controlling the orientation, a release film or a porous film is arranged on the front and back of the LCP extruded film 100, and thermocompression bonding is performed while sandwiching it between endless belt pairs of a double belt press machine. After that, a thermocompression forming method for removing the release film or the porous film is preferably used. The thermal pressure molding method may be performed with reference to, for example, Japanese Patent Application Laid-Open No. 2010-2216994. The processing temperature when the LCP extrusion film 100 using the above resin composition is hot-press formed between the endless belt pairs of the double belt press machine is a liquid crystal polymer in order to control the crystal state of the LCP extrusion film 100. The temperature is preferably higher than the melting point and 70 ° C. higher than the melting point, more preferably + 5 ° C. higher than the melting point, 60 ° C. higher than the melting point, still more preferably + 10 ° C. higher than the melting point, and the melting point. The temperature is 50 ° C. higher or lower. The thermocompression bonding conditions at this time can be appropriately set according to the desired performance, and are not particularly limited, but are preferably performed under the conditions of a surface pressure of 0.5 to 10 MPa and a heating temperature of 250 to 430 ° C., more preferably. Is a surface pressure of 0.6 to 8 MPa and a heating temperature of 260 to 400 ° C., more preferably a surface pressure of 0.7 to 6 MPa and a heating temperature of 270 to 370 ° C. On the other hand, when a non-contact heater or an oven is used, it is preferable to carry out the operation at 200 to 320 ° C. for 1 to 20 hours, for example.

(Insulation material for circuit boards)
FIG. 6 is a schematic cross-sectional view showing a main part of the insulating material 200 for a circuit board of the present embodiment. The insulating material 200 for a circuit board of the present embodiment includes the above-mentioned LCP extruded film 100 and a laminate having at least a woven fabric WF provided on one side and / or both sides of the LCP extruded film 100.

Specifically, the insulating material 200 for a circuit board includes a laminated body having a laminated structure (three-layer structure) in which the LCP extruded film 100, the woven fabric WF, and the LCP extruded film 100 are arranged at least in this order. .. In this laminated body, one LCP extruded film 100 is provided on the front surface side of the woven fabric WF, and the other LCP extruded film 100 is provided on the back surface side of the woven fabric WF. These three layers are thermocompression bonded to form a three-layer structure laminate. Although a three-layer structure laminate is exemplified here, the present invention further laminates the LCP extrusion film 100 and the woven cloth WF even if the two-layer structure laminate omits one of the LCP extrusion films 100. Needless to say, it is possible to carry out even a laminated body having a laminated structure of four or more layers.

Here, in the present specification, "the woven fabric WF is provided on one side and / or both sides of the LCP extruded film 100" means that the LCP extruded film 100 is directly placed on the surface of the woven fabric WF as in the present embodiment. The LCP extruded film 100 is separated from the woven fabric WF by an arbitrary layer (for example, a primer layer, an adhesive layer, etc.) (for example, a primer layer, an adhesive layer, etc.) not shown between the LCP extruded film 100 and the woven fabric WF. It is meant to include the arranged aspects.

The woven cloth WF is a cloth woven with fibers. The type of fiber of the woven fabric WF is not particularly limited, and any of inorganic fiber, organic fiber, and organic-inorganic hybrid fiber can be used. In particular, an inorganic fiber woven fabric WF is preferably used. By thermocompression bonding the woven fabric WF of the inorganic fiber to the LCP extruded film 100, the anisotropy of the dimensional change rate in the MD direction and the TD direction can be kept small, and in a more preferable embodiment, the dimensional change rate in the MD direction and the TD direction. It can be made smaller. As the woven fabric WF, a commercially available product can be used, and the woven fabric WF can be manufactured by a method known in the art.

Examples of the inorganic fiber include glass fibers such as E glass, D glass, L glass, M glass, S glass, T glass, Q glass, UN glass, NE glass and spherical glass, and inorganic fibers other than glass such as quartz. Examples thereof include ceramic fibers such as silica, but the present invention is not particularly limited thereto. As the woven fabric of inorganic fibers, a woven fabric that has been subjected to a fiber opening treatment or a filling treatment is suitable from the viewpoint of dimensional stability. Among these, glass cloth is preferable from the viewpoint of mechanical strength, dimensional stability, water absorption and the like. From the viewpoint of enhancing the thermocompression bonding property with the LCP extruded film 100, a glass cloth that has been subjected to a fiber opening treatment or a filling treatment is preferable. Further, glass cloth surface-treated with a silane coupling agent such as epoxy silane treatment and amino silane treatment can also be preferably used. The woven fabric WF may be used alone or in combination of two or more.

The thickness of the woven fabric WF can be appropriately set according to the required performance and is not particularly limited. From the viewpoint of stackability, processability, mechanical strength, etc., it is preferably 10 to 300 μm, more preferably 10 to 200 μm, and even more preferably 15 to 180 μm.

The total thickness of the insulating material 200 for a circuit board can be appropriately set according to the required performance, and is not particularly limited. From the viewpoint of stackability, processability, mechanical strength, etc., it is preferably 30 to 500 μm, more preferably 50 to 400 μm, still more preferably 70 to 300 μm, and particularly preferably 90 to 250 μm.

By adopting the above-described configuration, the circuit board insulating material 200 of the present embodiment has a small anisotropy of the dimensional change rate in the MD direction and the TD direction, and more preferably, the dimensional change in the MD direction and the TD direction. The rate itself can be reduced, and the dielectric properties in the high frequency range are excellent, and it has a remarkable effect of being easy to manufacture and excellent in productivity.

The above-mentioned insulating material 200 for a circuit board can be manufactured by appropriately applying a known manufacturing method, and the manufacturing method is not particularly limited. As an example, for example, the LCP extruded film 100 and the woven fabric WF are laminated, heated and pressurized, and the LCP extruded film 100 and the woven fabric WF are thermocompression bonded to obtain an insulating material 200 for a circuit board. Can be done. Further, the LCP extruded film 100, the woven fabric WF, and the LCP extruded film 100 are laminated in this order to form a laminated body, and the laminated body is heated and pressed while being sandwiched by a press machine, a double belt press machine, or the like. A method of hot-pressing the insulating material 200 for a circuit board is also preferable. The processing temperature during thermocompression bonding can be appropriately set according to the required performance and is not particularly limited, but is preferably 200 to 400 ° C, more preferably 250 to 360 ° C, and further preferably 270 to 350 ° C. be. The processing temperature at the time of thermocompression bonding is a value measured by the surface temperature of the LCP extruded film 100 of the above-mentioned laminated body. The pressurizing conditions at this time can be appropriately set according to the desired performance, and are not particularly limited, but are, for example, at a surface pressure of 0.5 to 10 MPa for 1 to 240 minutes, more preferably a surface pressure of 0.8 to. It takes 1 to 120 minutes at 8 MPa.

(Metal leaf-clad laminate)
FIG. 7 is a schematic cross-sectional view showing a main part of the metal leaf-covered laminated plate 300 of the present embodiment. The metal foil-clad laminate 300 of the present embodiment includes the above-mentioned LCP extruded film 100 and a metal foil MF provided on one side and / or both sides of the LCP extruded film 100.

Specifically, the metal foil-clad laminate 300 is a double-sided metal foil-clad laminate having a laminated structure (three-layer structure) in which the metal foil MF, the LCP extruded film 100, and the metal foil MF are arranged in at least this order. be. These three layers are thermocompression bonded to form a three-layer structure laminate. Although the double-sided metal foil-clad laminate is shown in the present embodiment, the present invention can also be implemented in an embodiment in which the metal leaf MF is provided only on one surface of the LCP extruded film 100. That is, although a three-layer structure laminate is exemplified here, in the present invention, the LCP extruded film 100 and the woven fabric WF are further laminated even in the two-layer structure laminate in which one of the metal foil MFs is omitted. Needless to say, it is possible to carry out even a laminated body having a laminated structure of four or more layers.

FIG. 8 is a schematic cross-sectional view showing a main part of the metal leaf-covered laminated plate 400 of the present embodiment. The metal leaf-clad laminate 400 of the present embodiment is a laminate having at least the above-mentioned woven cloth WF provided on one side and / or both sides of the above-mentioned LCP extruded film 100 and the above-mentioned LCP extruded film 100, and the laminate. It is provided with a metal foil MF provided on one side and / or both sides.

Specifically, the metal foil-clad laminate 400 has a laminated structure (five-layer structure) in which a metal foil MF, an LCP extruded film 100, a woven cloth WF, an LCP extruded film 100, and a metal foil MF are arranged at least in this order. It is a double-sided metal leaf-covered laminated board having. These five layers are thermocompression bonded to form a five-layer structure laminate. Although the double-sided metal leaf-clad laminate is shown in the present embodiment, the present invention can also be implemented in an embodiment in which the metal leaf MF is provided on only one surface. That is, although a five-layer structure laminate is exemplified here, in the present invention, even if one of the four-layer structure laminates omits the metal foil MF, the LCP extruded film 100, the insulating material 200 for the circuit board, and the like are used. Needless to say, it is possible to carry out even a laminated body having a laminated structure of 6 or more layers in which the woven fabric WF is further laminated.

The material of the metal foil MF is not particularly limited, and examples thereof include gold, silver, copper, copper alloys, nickel, nickel alloys, aluminum, aluminum alloys, iron, and iron alloys. Among these, copper foil, aluminum foil, stainless steel foil, and alloy foil of copper and aluminum are preferable, and copper foil is more preferable. As the copper foil, any one produced by a rolling method, an electrolysis method or the like can be used, but an electrolytic copper foil or a rolled copper foil having a relatively large surface roughness is preferable.

The thickness of the metal foil MF can be appropriately set according to the desired performance and is not particularly limited. Usually, it is preferably 1.5 to 1000 μm, more preferably 2 to 500 μm, still more preferably 5 to 150 μm, and particularly preferably 7 to 100 μm. The metal leaf MF may be subjected to surface treatment such as chemical surface treatment such as pickling as long as the action and effect of the present invention are not impaired. The type and thickness of the metal foil MF may be the same or different.

The method of providing the metal foil MF on the surface of the LCP extruded film 100 or the insulating material 200 for a circuit board can be performed according to a conventional method, and is not particularly limited. A method of laminating a metal foil MF on an LCP extruded film 100 or an insulating material 200 for a circuit board to bond or crimp both layers, a physical method such as sputtering or vapor deposition (dry method), after electroless plating or electroplating. It may be either a chemical method (wet method) such as electrolytic plating, or a method of applying a metal paste. Further, a laminate obtained by laminating an LCP extruded film 100 or an insulating material 200 for a circuit board and one or more metal foil MFs is heated by using, for example, a multi-stage press machine, a multi-stage vacuum press machine, a continuous molding machine, an autoclave molding machine, or the like. By pressing, metal foil-clad laminates 300, 400 can also be obtained.

The above-mentioned metal foil-clad laminates 300 and 400 can be manufactured by appropriately applying a known manufacturing method, and the manufacturing method is not particularly limited. As an example, for example, the LCP extruded film 100 or the insulating material 200 for a circuit board and the metal leaf MF are superposed to form a laminated body in which the metal foil MF is placed on the LCP extruded film 100, and this laminated body is doubled. A method of hot pressure forming while sandwiching between endless belt pairs of a belt press machine can be mentioned. As described above, the LCP extruded film 100 used in the present embodiment has a small anisotropy of the dimensional change rate in the MD direction and the TD direction, and more preferably, the dimensional change rate itself in the MD direction and the TD direction is small. High peel strength to the metal foil MF can be obtained.

The temperature at the time of thermal pressure bonding of the metal foil MF can be appropriately set according to the required performance, and is not particularly limited, but is preferably a temperature 50 ° C. lower than the melting point of the liquid crystal polymer and 50 ° C. higher than the melting point. It is preferable that the temperature is 40 ° C. lower than the melting point and 40 ° C. higher than the melting point, more preferably 30 ° C. lower than the melting point and 30 ° C. higher than the melting point, and 20 ° C. or higher than the melting point. It is particularly preferable that the temperature is 20 ° C. higher than the melting point. The temperature at the time of thermocompression bonding of the metal foil MF is a value measured by the surface temperature of the LCP extruded film 100 described above. The crimping conditions at this time can be appropriately set according to the desired performance and are not particularly limited. For example, when a double belt press machine is used, the surface pressure is 0.5 to 10 MPa and the heating temperature is 200 to 360 ° C. It is preferable to carry out under the conditions.

The metal foil-clad laminates 300 and 400 of the present embodiment may have another laminated structure or a further laminated structure as long as the thermocompression bonding body having a two-layer structure of the LCP extruded film 100 and the metal foil MF is provided. .. For example, a two-layer structure of a metal foil MF / LCP extruded film 100; a three-layer structure such as a metal foil MF / LCP extruded film 100 / metal foil MF, an LCP extruded film 100 / metal foil MF / LCP extruded film 100; / LCP Extruded Film 100 / Woven WF / LCP Extruded Film 100-like 4-layer structure; Metal Foil MF / LCP Extruded Film 100 / Metal Foil MF / LCP Extruded Film 100 / Metal Foil MF, Metal Foil MF / LCP Extruded Film It can have a multi-layer structure such as 100 / woven cloth WF / LCP extruded film 100 / metal foil MF-like five-layer structure; Further, a plurality of (for example, 2 to 50) metal foil-clad laminated plates 300 and 400 can be thermocompression-bonded.

In the metal foil-clad laminates 300 and 400 of the present embodiment, the peel strength of the LCP extruded film 100 and the metal foil MF is not particularly limited, but is 0.8 (N / mm) from the viewpoint of providing higher peel strength. ) Or more, more preferably 1.0 (N / mm) or more, still more preferably 1.2 (N / mm) or more. As described above, in the metal foil-clad laminates 300 and 400 of the present embodiment, high peel strength can be realized, so that peeling between the LCP extruded film 100 and the metal leaf MF can be suppressed, for example, in the heating process of substrate manufacturing. In addition, since manufacturing conditions with excellent process margin and productivity can be applied to obtain the same peel strength as the conventional technique, the basic performance of the liquid crystal polymer deteriorates while maintaining the same level of peel strength as the conventional technique. Can be suppressed.

The metal foil-clad laminates 300, 400 of the present embodiment can be used as a material for a circuit board such as an electronic circuit board or a multilayer board by pattern-etching at least a part of the metal foil MF. Further, the metal foil-clad laminates 300 and 400 of the present embodiment are excellent in dielectric properties in the high frequency region, have small dimensional change rate anisotropy in the MD direction and the TD direction, and in a more preferable embodiment, the MD direction and the TD. Insulation material such as flexible printed wiring board (FPC) in 5th generation mobile communication system (5G) and millimeter wave radar because the dimensional change rate itself in the direction is small, dimensional stability is excellent, manufacturing is easy and productivity is excellent. It is a particularly useful material.

(LCP stretched film)
In each of the above-described embodiments, the LCP extruded film 100 obtained by extruding a resin composition containing a thermoplastic liquid crystal polymer into a film is used, but if necessary, the LCP extruded film 100 is further added with 1 It can also be used in the form of an LCP stretched film (stretched body of the LCP extruded film 100) after undergoing a shaft and / or biaxial stretching treatment. Then, using this LCP stretched film, the above-mentioned insulating material 200 for a circuit board, metal leaf-clad laminates 300, 400 and the like can be constructed.

The setting conditions for the stretching treatment may be appropriately set according to the type and composition of the resin composition to be used, the desired performance of the target LCP stretched film, and the like, and are not particularly limited. In the case of uniaxial stretching, for example, the LCP extruded film 100 can be stretched 1.1 to 2.5 times in the TD direction (Transverse Direction) at 90 to 180 ° C., and then 100 to, for example. It is preferable to perform heat treatment (heat setting) at 240 ° C. for 1 to 600 seconds. In the case of biaxial stretching, for example, the LCP extruded film 100 is preferably stretched 1.1 to 2.5 times at 70 to 180 ° C. in the MD direction (longitudinal direction) to obtain a uniaxially stretched film. After that, it can be further stretched 1.1 to 2.5 times in the TD direction (Transverse Direction) at 90 to 180 ° C., and then heat-treated at 100 to 240 ° C. for 1 to 600 seconds (heat set). ) Is preferable. At this time, simultaneous biaxial stretching may be performed instead of sequential stretching. The draw ratio is not particularly limited, but from the viewpoints of improving film transportability, releasability, suppressing thickness unevenness, wrinkles, etc., the total draw ratio in the MD direction × TD direction (the draw ratio in the MD direction is m). When the stretching ratio in the TD direction is n, the stretching ratio expressed in m × n) is preferably 1.1 times or more, more preferably 1.2 times or more, still more preferably 1.3 times or more. Particularly preferably, it is 1.5 times or more. The upper limit thereof is not particularly limited, but is 3.0 times or less as a guideline, preferably 2.7 times or less, more preferably less than 2.5 times, and more preferably less than 2.3 times. Further, in the case of heat setting, a method known in the art, for example, a contact type heat treatment, a non-contact heat treatment, or the like can be performed, and the type thereof is not particularly limited. For example, heat can be set by using known equipment such as a non-contact heater, an oven, a blow device, a heat roll, a cooling roll, a heat press machine, and a double belt heat press machine. At this time, if necessary, a release film or a porous film known in the art can be arranged on the surface of the LCP stretched film to perform thermal pressure treatment.

The linear expansion coefficient (CTE, α2, 23 to 200 ° C.) of the LCP extruded film 100 in the MD direction and the TD direction of the LCP stretched film (stretched body of the LCP extruded film 100) can be appropriately set according to the desired performance. Although not particularly limited, each of them should be in the range of -20 to 15 ppm / K from the viewpoint of reducing the anisotropy of the dimensional change rate and the absolute value of the dimensional change rate and improving the adhesion to the metal foil. Is preferable, each is in the range of -15 to 10 ppm / K, more preferably in the range of -10 to 5 ppm / K, and each in the range of -10 to 0 ppm / K. Is particularly preferable.

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. That is, the materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Further, the values of various manufacturing conditions and evaluation results in the following examples have meanings as a preferable upper limit value or a preferable lower limit value in the embodiment of the present invention, and the preferable numerical range is the above-mentioned upper limit value or the lower limit value. It may be in the range specified by the combination of the value and the value of the following examples or the values of the examples.

[Melting viscosity]
The melt viscosity [Pa · sec] of each LCP extruded film was measured under the following conditions.
Measuring equipment: Capillograph 1D (manufactured by Toyo Seiki Seisakusho Co., Ltd.)
Equipment used: Cylinder length 10.00 mm, cylinder diameter 1.00 mm, barrel diameter 9.55 mm
Measurement conditions: Temperature [° C] and shear rate [sec ^-1 ] during extrusion molding of each LCP extruded film

[Orientation]
Using an X-ray diffractometer Smartlab (manufactured by Rigaku Co., Ltd.), X-ray diffraction measurement of each LCP extruded film including the film surface S1 or the film surface S2 was performed by a transmission method, and the degree of orientation was measured. Here, a Cu-encapsulated tube is used as the X-ray source, and X-ray diffraction measurement (2θ / θ scan, β scan) is performed by a parallel beam optical system and a transmission method. First, 2θ = 19.5 ° in a 2θ / θ scan. It was confirmed that there is a peak top in. Next, the intensity distribution in the azimuth direction was obtained by measuring the intensity from 0 ° to 360 ° in the azimuth direction with respect to the diffraction peak of 2θ = 19.5 by β scan. From the base intensity (isotropic component) and peak intensity (orientation component) of the obtained β profile, the degree of orientation was calculated from the above formula based on the area ratio of the orientation peak.
For the film surface S2 of each LCP extruded film, each LCP extruded film was immersed in a 70% monoethylamine aqueous solution (manufactured by Daicel) under a 23 ° C. and 50% RH environment for 168 hours, and both surfaces of each LCP extruded film were exposed. It was adjusted by etching 5 μm, then washing with running water for 5 minutes, further washing with distilled water, drying at 80 ° C. for 1 hour, and cooling at 23 ° C. and 50% RH environment for 24 hours, respectively.

[Coefficient of linear expansion]
The linear expansion coefficient of each LCP extruded film and LCP stretched film was measured by the TMA method according to JIS K7197.
Measuring equipment: TMA 4000SE (manufactured by NETZSCH)
Measurement method: Tensile mode Measurement conditions: Sample size 25 mm x 4 mm x thickness 50 μm
Distance between chucks 20 mm
Temperature interval 23-200 ° C (2ndRUN)
Heating rate 5 ° C / min
Atmosphere Nitrogen (flow rate 50 ml / min)
Test load 5gf
* The 2ndRUN value is used to see the value after eliminating the heat history.

[Tape peeling test]
Adhesion test was performed on the film surface S1 of each LCP extruded film by a cross-cut method based on JIS K5600-5-6, and the presence or absence of a skin layer was confirmed. At this time, a cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. having a width of 24 mm and a length of 50 mm is used. Yes. "
○ No skin layer × With skin layer

[Dimensional change rate after metal leaf etching and its anisotropy]
Copper foil / LCP extruded film by laminating an electrolytic copper foil (TQ-M7VSP manufactured by Mitsui Metal Co., Ltd.) with a thickness of 12 μm on both sides of each LCP extruded film and heat-pressing at a temperature condition of 320 ° C. and a surface pressure of 1 MPa for 1 minute. / A double-sided metal foil-clad laminate having a three-layer structure of copper foil was produced. Then, the double-sided metal obtained in accordance with JPCA-UB01 (2017) and in accordance with "16.4.4-18 Dimensional change rate" and "16.4.4-2-2 Sample preparation by removing copper foil" of the same standard. Samples were prepared from the foil-clad laminates, and the dimensional change rate of each sample after copper foil etching was measured using a measuring microscope (MF-A4020C manufactured by Mitutoyo Co., Ltd.) to evaluate the anisotropy of the dimensional change rate. Here, β ₁ represents the dimensional change rate in the MD direction, and β ₂ represents the dimensional change rate in the TD direction.
◎ The anisotropy of the dimensional change rate is very small (｜ β ₂ -β ₁ ｜ ≦ 0.3%)
〇 The anisotropy of the dimensional change rate is small (0.3% <| β ₂ -β ₁ | <0.4%)
× The anisotropy of the dimensional change rate is large (0.4% ≤ | β ₂ -β ₁ |)

(Examples 1 to 3)
As an intermediate layer, a type II thermoplastic liquid crystal polymer (a copolymer having a monomer composition of 74 mol% p-hydroxybenzoic acid and 26 mol% 6-hydroxy-2-naphthoic acid, a temperature of 300 ° C. and a shear rate of 500 sec ^-1 has a melt viscosity of 80 Pa. For sec), a polycarbonate PC (Panlite L-1225L manufactured by Teijin Co., Ltd.) was used as the surface layer on both sides of the intermediate layer, and the die width was 600 mm and the lip opening was 0.2 to 1 under the molding conditions shown in Table 1. Each resin was co-extruded at 300 ° C. from a two-kind three-layer extruder equipped with a 0 mm T-die by a T-die casting method to form a two-kind three-layer film having an intermediate layer of 50 μm. The polycarbonate films on both surface layers were peeled off from the molded two-kind three-layer film by a take-up line to obtain LCP extruded films of Examples 1 to 3 having a melting point of 280 ° C. and a thickness of 50 μm, respectively.
Further, a thermocompression bonding treatment at 300 ° C. for 5 minutes with a glass cloth (IPC No. # 1037) sandwiched between the obtained pair of thermoplastic liquid crystal polymer films of Examples 1 to 3 at 300 ° C. To obtain an insulating material for a circuit board of Examples 1 to 3 having a melting point of 280 ° C. and a total thickness of 100 μm.

(Comparative Example 1)
Type II thermoplastic liquid crystal polymer (monomer composition: 74 mol% p-hydroxybenzoic acid, 26 mol% 6-hydroxy-2-naphthoic acid, temperature 300 ° C. and shear rate 500 sec ^-1 melt viscosity 80 Pa · sec) The liquid crystal polymer is extruded at 300 ° C. by the T-die casting method from a single-layer extruder equipped with a T-die having a die width of 600 mm and a lip opening of 0.3 mm under the molding conditions shown in Table 1, and has a melting point of 280 ° C. and An LCP extruded film of Comparative Example 1 having a thickness of 50 μm was obtained.

(Comparative Examples 2 to 4)
The LCP extruded films of Comparative Examples 2 to 4 having a melting point of 280 ° C. and a thickness of 50 μm were obtained in the same manner as in Example 1 except that the molding conditions were changed as shown in Table 1.

(Examples 4 to 6)
Type I thermoplastic liquid crystal polymer instead of type II thermoplastic liquid crystal polymer (monomer composition of 79 mol% p-hydroxybenzoic acid, 20 mol% 6-hydroxy-2-naphthoic acid, 1 mol% terephthalic acid, temperature 330 ° C. And the melt viscosity of a shear rate of 500 sec ^-1 is 70 Pa · sec), and each resin is co-extruded at 330 ° C. in the same manner as in Example 1 with a melting point of 315 ° C. and a thickness of 50 μm. The LCP extruded films of Examples 4 to 6 were obtained, respectively.
Further, a thermocompression bonding treatment at 330 ° C. for 5 minutes using a heat press machine with a glass cloth (IPC No. # 1037) sandwiched between the obtained pair of thermoplastic liquid crystal polymer films of Examples 4 to 6. To obtain an insulating material for a circuit board of Examples 4 to 6 having a melting point of 315 ° C. and a total thickness of 100 μm.

(Comparative Example 5)
Type I thermoplastic liquid crystal polymer instead of type II thermoplastic liquid crystal polymer (monomer composition of 79 mol% p-hydroxybenzoic acid, 20 mol% 6-hydroxy-2-naphthoic acid, 1 mol% terephthalic acid, temperature 330 ° C. The LCP of Comparative Example 2 having a melting point of 315 ° C. and a thickness of 50 μm in the same manner as in Comparative Example 1 except that the liquid crystal polymer was extruded at 330 ° C. using a melt viscosity of 500 sec ^-1 and a melt viscosity of 70 Pa · sec). An extruded film was obtained.

(Comparative Examples 6 to 8)
The LCP extruded films of Comparative Examples 6 to 8 having a melting point of 315 ° C. and a thickness of 50 μm were obtained by the same method as in Example 4 except that the molding conditions were changed as shown in Table 2.

(Examples 7 to 9)
LCP extrusion of Examples 7 to 9 having a melting point of 280 ° C. and a thickness of 50 μm by the same method as in Example 1 except that polymethylpentene PMP (TPX MX004 manufactured by Mitsui Chemicals, Inc.) is used for the surface layers on both sides instead of polycarbonate. I got a film.
Further, a thermocompression bonding treatment at 300 ° C. for 5 minutes using a heat press machine with a glass cloth (IPC No. # 1037) sandwiched between the obtained pair of thermoplastic liquid crystal polymer films of Examples 7 to 9. To obtain an insulating material for a circuit board of Examples 7 to 9 having a melting point of 280 ° C. and a total thickness of 100 μm.

(Comparative Examples 9 to 11)
The LCP extruded films of Comparative Examples 9 to 11 having a melting point of 280 ° C. and a thickness of 50 μm were obtained by the same method as in Example 7 except that the molding conditions were changed as shown in Table 3.

Tables 4 to 6 show the measurement results.

The obtained LCP extruded films of Examples 1, 4 and 7 were stretched 1.5 times in the TD direction at 130 ° C. using a uniaxial stretching machine (total draw ratio: 1.5 times), and 2 at 130 ° C. By heat setting for 1 minute, LCP stretched films were obtained respectively.

Table 7 shows the measurement results.

The obtained LCP extruded films of Examples 1, 4 and 7 were stretched 2.0 times (total draw ratio: 2.0 times) in the TD direction at 130 ° C. using a uniaxial stretching machine, and 2 at 130 ° C. LCP stretched films were obtained by heat setting for 1 minute.

Table 8 shows the measurement results.

The LCP extruded film of the present invention can be widely and effectively used in applications such as electronic circuit boards, multilayer boards, high heat dissipation boards, flexible printed wiring boards, antenna boards, optoelectronic mixed boards, and IC packages, and in particular, ultrafine processing. Because it is compatible with and highly reliable, it can be used particularly widely and effectively as an insulating material such as flexible printed wiring boards (FPC) in 5th generation mobile communication boards (5G) and millimeter wave radars, and metal foil-clad laminates. It is possible.

100 ・ ・ ・ LCP extruded film 100a ・ ・ ・ Surface 100b ・ ・ ・ Surface S1 ・ ・ ・ Film surface S2 ・ ・ ・ Film surface with depth of 5 μm 200 ・ ・ ・ Insulation material for circuit board 300 ・ ・ ・ Metal leaf-clad laminate 400 ・ ・ ・ Metal foil-clad laminate WF ・ ・ ・ Woven cloth MF ・ ・ ・ Metal leaf

Claims (16)

An LCP extruded film containing a thermoplastic liquid crystal polymer and having a thickness of 15 μm or more and 300 μm or less.
Orientation degree α1 (%) including the exposed film surface S1 and orientation degree including the film surface S2 located at a depth of 5 μm from the film surface S1 exposed by etching the film surface S1 in the thickness direction. At 23 to 200 ° C., where α2 (%) satisfies the relationship of -4.0 ≦ [(α2-α1) / α1] × 100 ≦ 0.0 and is measured by the TMA method based on JIS K7197. The coefficient of linear expansion in the MD and TD directions is in the range of -30 to 55 ppm / K.
LCP extruded film. The LCP extruded film according to claim 1, wherein the coefficient of linear expansion in the TD direction is 0 to 55 ppm / K. The LCP extruded film according to claim 1 or 2, wherein both outer layers are removed from a laminated extruded film having an outer layer, an intermediate layer, and an outer layer. The LCP extruded film according to any one of claims 1 to 3, which has no tape peelable skin layer on the film surface S1 in an adhesion test by a cross-cut method according to JIS K5600-5-6. .. The LCP extruded film according to any one of claims 1 to 4, wherein the degree of orientation α2 including the surface S2 is 37.7 (%) or less. The LCP extruded film according to any one of claims 1 to 5, wherein the degree of orientation α1 including the film surface S1 is 39.0 (%) or less. The LCP extruded film according to any one of claims 1 to 6, further comprising an inorganic filler. The LCP extruded film according to any one of claims 1 to 7, which is a T-die extruded film. A laminate comprising the LCP extruded film according to any one of claims 1 to 8 and a woven fabric provided on at least one surface of the LCP extruded film.
Insulation material for circuit boards. The LCP extruded film according to any one of claims 1 to 8 and metal foils provided on one side and / or both sides of the LCP extruded film are provided.
Metal leaf-clad laminate. A laminate having at least the LCP extruded film and the woven fabric according to any one of claims 1 to 8, and metal foils provided on one side and / or both sides of the laminate.
Metal leaf-clad laminate. The stretched body of the LCP extruded film according to any one of claims 1 to 8 is provided.
LCP stretched film. The LCP stretched film according to claim 12, wherein the stretched body has a stretch ratio (MD direction × TD direction) of 1.3 to 2.5 times that of the LCP extruded film. A laminate comprising the LCP stretched film according to claim 12 or 13 and a woven fabric provided on at least one surface of the LCP stretched film.
Insulation material for circuit boards. The LCP stretched film according to claim 12 or 13 and the metal foil provided on one side and / or both sides of the LCP stretched film are provided.
Metal leaf-clad laminate. A laminate having at least the LCP stretched film and the woven fabric according to claim 12 or 13, and a metal foil provided on one side and / or both sides of the laminate.
Metal leaf-clad laminate.

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