Polymer film, laminate, and method for manufacturing the same

Abstract

Provided is: a polymer film including a polymer or liquid crystal polymer with a dielectric dissipation factor of 0.01 or less and a curable compound, said curable compound including a curable compound A which is an oligomer or a polymer; a laminate in which the polymer film is used; and a production method therefor.

Description

[Technical Field]

[0001] This disclosure relates to polymer films, laminates, and methods for manufacturing the same. [Background technology]

[0002] In recent years, the frequencies used in communication equipment have tended to become extremely high. To suppress transmission loss in the high-frequency band, it is required to lower the relative permittivity and dielectric loss tangent of the insulating materials used in circuit boards. Traditionally, polyimides have been widely used as insulating materials for circuit boards, but liquid crystal polymers, which have high heat resistance, low water absorption, and low loss in the high-frequency range, are attracting attention.

[0003] Conventional liquid crystal polymer films include, for example, a liquid crystal polyester film containing at least a liquid crystal polyester, wherein when the first degree of orientation is defined as the degree of orientation in a first direction parallel to the main surface of the liquid crystal polyester film, and the second degree of orientation is defined as the degree of orientation in a second direction parallel to the main surface and perpendicular to the first direction, the ratio of the first degree of orientation to the second degree of orientation, i.e., the first degree of orientation / second degree of orientation, is 0.95 or more and 1.04 or less, and the third degree of orientation of the liquid crystal polyester, measured by wide-angle X-ray scattering in a direction parallel to the main surface, is 60.0% or more.

[0004] Furthermore, a conventional functional membrane is known to be the one described in Patent Document 2. Patent Document 2 describes a resin layer comprising a polymer and a curable compound, having excellent adhesion to a metal layer, and a laminate for high-frequency circuits laminated with a metal foil.

[0005] Patent Document 1: Japanese Unexamined Patent Publication No. 2020-26474 Patent Document 2: International Publication No. 2019 / 054334 [Overview of the project] [Problems that the invention aims to solve]

[0006] The problem to be solved by the embodiments of the present invention is to provide a polymer film excellent in suppressing wiring distortion during wiring lamination. Another problem to be solved by the embodiments of the present invention is to provide a laminate using the above polymer film and a method for producing the same.

Means for Solving the Problems

[0007] The means for solving the above problems include the following aspects. <1> A polymer film containing a polymer having a dielectric loss tangent of 0.01 or less and a curable compound, wherein the curable compound contains a curable compound A which is an oligomer or a polymer. <2> A polymer film containing a liquid crystal polymer and a curable compound, wherein the curable compound contains a curable compound A which is an oligomer or a polymer. <3> The polymer film according to <1> or <2>, wherein the content of the curable compound A is higher on the surface than inside the polymer film. <4> The polymer film according to <1>, wherein the polymer having a dielectric loss tangent of 0.01 or less is a liquid crystal polymer. <5> The polymer film according to any one of <1> to <4>, wherein the melting point Tm or the 5% mass loss temperature Td of the polymer having a dielectric loss tangent of 0.01 or less or the liquid crystal polymer is 200°C or higher. <6> The polymer film according to any one of <1> to <5>, wherein the weight average molecular weight of the curable compound A is 10,000 or less. <7> The polymer film contains particles, The polymer film according to any one of <1> to <6>, wherein the curable compound is contained inside or on the surface of the particles. <8> The polymer film according to any one of <1> to <7>, wherein the polymer film contains a curing inhibitor. <9>The polymer film according to any one of <1> to <8>, wherein the polymer having a dielectric loss tangent of 0.01 or less or the liquid crystal polymer contains a liquid crystal polymer having a constitutional repeating unit represented by any one of Formula (1) to Formula (3). Formula (1) -O-Ar -CO- Formula (2) -CO-Ar 2 -CO- Formula (3) -X-Ar 3 -Y- In Formulas (1) to (3), Ar 1 represents a phenylene group, a naphthylene group or a biphenylylene group, Ar 2 and Ar 3 each independently represents a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following Formula (4), X and Y each independently represent an oxygen atom or an imino group, and the hydrogen atoms in Ar 1 ~Ar 3 may each independently be substituted with a halogen atom, an alkyl group or an aryl group. Formula (4) -Ar 4 -Z-Ar 5 - In Formula (4), Ar 4 and Ar 5 each independently represents a phenylene group or a naphthylene group, and Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylene group. <10>The polymer film according to any one of <1> to <9>, wherein the content of the curable compound A is 30% by mass to 100% by mass based on the total mass of the curable compounds. <11>The polymer film according to any one of <1> to <10>, wherein the ratio Es / Ec of the surface elastic modulus Es to the internal elastic modulus Ec at 160°C of the polymer film is 0.1 to 10. <12>Having a layer A and a layer B provided on at least one surface of the layer A, The polymer film according to any one of <1> to <11>, wherein the layer B contains a polymer having a dielectric loss tangent of 0.01 or less and the curable compound A. <13> It is a base film. <1> ~ <12> A polymer film as described in any one of the following. <14> It further has layer C, The above layer B, layer A, and layer C are in this order. <13> The polymer film described above. <15> It is a bonding sheet. <1> ~ <14> A polymer film as described in any one of the following. <16> <1> ~ <15> A laminate having a polymer film according to any one of the above, and a metal layer or metal wiring disposed on at least one surface of the polymer film. <17> The device comprises a metal layer or metal wiring, the polymer film, and the metal layer or metal wiring in this order. <16> The laminate described above. <18> The above curable compound A includes a cured product obtained by curing. <16> or <17> The laminate described above. <19> <1> ~ <15> A polymer film as described in any one of the following, and a metal layer or metal wiring, <1> ~ <15> A polymer film as described in any one of the following, and a metal layer or metal wiring, <1> ~ <15> A laminate having, in this order, a polymer film as described in any one of the above. <20> The metal in the above-mentioned metal layer or metal wiring is copper or silver. <16> ~ <19> A laminate as described in any one of the following. <21> A polymer film containing a polymer having a dielectric loss tangent of 0.01 or less and a curable compound, comprising a partial curing step to form the curable compound A by curing a portion of the curable compound, and a lamination step to form a laminate by laminating the film to a metal layer or metal wiring, in this order. <22> A method for manufacturing a laminate, comprising, in this order, a partial curing step to form the curable compound A by curing a portion of the curable compound in a polymer film containing a liquid crystal polymer and a curable compound, and a lamination step to form a laminate by laminating the film to a metal layer or metal wiring. <23> The loss tangent at 160°C of the layer containing the above-mentioned curable compound A is 0.03 or greater. <21> or <22> A method for manufacturing the laminate described above. <24> The loss tangent at 300°C of the layer containing the above-mentioned curable compound A is 0.1 or greater. <21> ~ <23> A method for manufacturing a laminate as described in any one of the following. <25> The bonding pressure in the bonding process described above is 0.1 MPa or higher. <21> ~ <24> A method for manufacturing a laminate as described in any one of the following. <26> After the bonding process described above, the content of the curable compound A is 30% to 100% by mass relative to the total mass of the curable compound. <21> ~ <25> A method for manufacturing a laminate as described in any one of the following. <27> <1> ~ <15> A method for manufacturing a laminate, comprising, in this order: a preparation step of preparing a polymer film according to any one of the above; a bonding step of bonding the polymer film to a metal layer or metal wiring to form a laminate; and a through-hole forming step of forming through holes in the layer containing the curable compound A in the laminate. <28> In the above through-hole formation process, at least a portion of the surface of the through-hole hardens. <27> A method for manufacturing the laminate described above. <29> The process includes a post-curing step in which the curable compound A is cured after the through-hole formation step described above. <27> or <28> A method for manufacturing the laminate described above. <30> The metal in the above-mentioned metal layer or metal wiring is copper or silver. <21> ~ <29> A method for manufacturing a laminate as described in any one of the following. [Effects of the Invention]

[0008] According to embodiments of the present invention, it is possible to provide a polymer film that exhibits excellent suppression of wiring distortion during wiring bonding. Furthermore, according to another embodiment of the present invention, a laminate using the above-mentioned polymer film and a method for manufacturing the same can be provided. [Modes for carrying out the invention]

[0009] The contents of this disclosure will be described in detail below. The descriptions of the constituent elements described below may be based on representative embodiments of this disclosure, but this disclosure is not limited to such embodiments. In this specification, the "~" symbol indicating a numerical range is used to mean that the numbers before and after it are included as the lower and upper limits, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples. Furthermore, in the notation of groups (atomic groups) in this specification, the notation that does not specify whether they are substituted or unsubstituted includes both those with and without substituents. For example, "alkyl group" includes not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups). In this specification, "(meth)acrylic" is a term used to encompass both acrylic and methacrylic, and "(meth)acryloyl" is a term used to encompass both acryloyl and methacryloyl. Furthermore, the term "process" in this specification includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. In addition, in this disclosure, "mass%" and "weight%" are synonymous, and "parts by mass" and "parts by weight" are synonymous. Furthermore, in this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. Furthermore, unless otherwise specified, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) in this disclosure are molecular weights obtained by detecting the solvent PFP (pentafluorophenol) / chloroform = 1 / 2 (mass ratio) using a gel permeation chromatography (GPC) analyzer with a TSKgel SuperHM-H (product name of Tosoh Corporation) column, and converting them using a differential refractometer, with polystyrene as the standard substance.

[0010] (Polymer film) A first embodiment of the polymer film according to this disclosure includes a polymer having a dielectric loss tangent of 0.01 or less, and a curable compound, wherein the curable compound is an oligomer or a polymer, and comprises curable compound A. A second embodiment of the polymer film according to this disclosure comprises a liquid crystal polymer and a curable compound, wherein the curable compound is curable compound A, which is an oligomer or a polymer.

[0011] In this specification, unless otherwise specified, the term "polymer film relating to this disclosure" refers to both the first and second embodiments described above.

[0012] The inventors have found that when conventional polymer films are bonded to wiring (especially metal wiring), the stress during bonding often causes distortion in the wiring. As a result of diligent research by the inventors, it has been found that by adopting the above configuration, a polymer film can be provided that exhibits excellent suppression of wiring distortion during wiring bonding. The detailed mechanism by which the above effects are achieved is unknown, but it is speculated to be as follows. By including curable compound A, which is an oligomer or polymer, as the curable compound, it is possible to achieve a half-cured state (also called "partially cured state" or "B-stage state") or a state close to it, in which only a portion of the curable compound has hardened. This is presumed to provide excellent flexibility and shape conformability (contour conformability), reduce stress during wiring bonding, and suppress wiring distortion. Furthermore, the polymer film relating to this disclosure can be further strengthened after lamination by curing the above-mentioned curable compound A.

[0013] <Curable compound> The polymer film relating to this disclosure includes a curable compound, and the curable compound A is an oligomer or a polymer. The curable compound in this disclosure is a compound having a curable group, and may be a monomer, oligomer, or polymer. Furthermore, the curable compound A is an oligomer or a polymer, and from the viewpoint of mechanical strength, it is preferably a polymer. In this disclosure, the oligomer is defined as a polymer with a weight-average molecular weight of 1,000 or more and less than 2,000, and the polymer is defined as a polymer with a polymerization-average molecular weight of 2,000 or more. Furthermore, from the viewpoint of adhesion and uneven distribution with metal foil or metal wiring, the curable compound A is preferably an oligomer or polymer with a weight-average molecular weight of 1,000 or more, more preferably a polymer with a weight-average molecular weight of 2,000 or more, even more preferably a polymer with a weight-average molecular weight of 3,000 to 200,000, and particularly preferably a polymer with a weight-average molecular weight of 5,000 to 100,000. Furthermore, from the viewpoint of suppressing wiring distortion, the weight-average molecular weight of the curable compound A is preferably 100,000 or less, more preferably 50,000 or less, and particularly preferably 10,000 or less.

[0014] Furthermore, from the viewpoint of suppressing wiring distortion, it is preferable that the polymer film relating to this disclosure has a higher content of the curable compound A on the surface than on the interior of the polymer film. Here, the surface of a polymer film refers to the outer surface of the polymer film (the surface in contact with air or the substrate), and is defined as the smaller of either a range of 3 μm in the depth direction from the outermost surface, or a range of 10% or less of the total thickness of the polymer film from the outermost surface. The interior of a polymer film refers to the part of the polymer film other than the surface, i.e., the inner surface of the polymer film (the surface that does not come into contact with air or the substrate), and is defined as the smaller of either a range of ±1.5 μm from the center in the thickness direction of the polymer film, or a range of ±5% of the total thickness from the center in the thickness direction of the polymer film. Furthermore, from the viewpoint of suppressing wiring distortion, it is preferable that the polymer film according to this disclosure contains particles, and that the curable compound is contained inside or on the surface of the particles. Examples of the above-mentioned particles include microcapsules or microgels having the above-mentioned curable compound inside or on their surface. Among these, microcapsules or microgels containing the above-mentioned curable compound are particularly preferred. Furthermore, the above particles are preferably organic resin particles.

[0015] The number of curable groups in a curable compound may be one or more, or two or more, but it is preferable that it be two or more. Furthermore, the curable compound may have only one type of curable group, or it may have two or more types of curable groups.

[0016] The curable groups mentioned above are not particularly limited as long as they are curable, but examples include ethylenically unsaturated groups, epoxy groups, oxetanyl groups, isocyanate groups, acid anhydride groups, carbodiimide groups, N-hydroxyester groups, glyoxal groups, imide ester groups, alkyl halogens, thiol groups, hydroxyl groups, carboxyl groups, amino groups, amide groups, aldehyde groups, sulfonic acid groups, and the like. When the above-mentioned curable compound A is formed by the half-cure method described later, an ethylenically unsaturated group is preferred as the curable group. In that case, it is preferable to use a polyfunctional ethylenically unsaturated compound as the curable compound.

[0017] A thermosetting resin is a preferred example of the curable compound A mentioned above. Examples of thermosetting resins include epoxy resins, phenolic resins, unsaturated imide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins. Furthermore, the thermosetting resin is not limited to these examples, and any known thermosetting resin can be used. These thermosetting resins can be used individually or in combination. Furthermore, a commercially available thermosetting resin-containing adhesive can be used as the curable compound A.

[0018] Furthermore, as the curable compound A mentioned above, a curable compound obtained by half-curing a monomer is preferred. The monomer is preferably an ethylenically unsaturated compound, and more preferably a polyfunctional ethylenically compound. Examples of ethylenically unsaturated compounds include (meth)acrylate compounds, (meth)acrylamide compounds, (meth)acrylic acid, styrene compounds, vinyl acetate compounds, vinyl ether compounds, and olefin compounds. Among these, (meth)acrylate compounds are preferred. Furthermore, from the viewpoint of adhesion to metal foil or metal wiring, the molecular weight of the monomer is preferably 50 or more and less than 1,000, more preferably 100 or more and less than 1,000, and particularly preferably 200 or more and 800 or less.

[0019] Furthermore, if the curable compound includes an ethylenically unsaturated compound, the polymer film according to this disclosure preferably includes a polymerization initiator. The polymerization initiator is preferably a thermal polymerization initiator or a photopolymerization initiator. Known thermal polymerization initiators or photopolymerization initiators can be used. Examples of thermal polymerization initiators include thermal radical generators. Specifically, these include peroxide initiators such as benzoyl peroxide and azobisisobutyronitrile, as well as azo-based initiators. Examples of photopolymerization initiators include photoradical generators. Specifically, these include (a) aromatic ketones, (b) onium salt compounds, (c) organic peroxides, (d) thio compounds, (e) hexaarylbiimidazole compounds, (f) ketoxime ester compounds, (g) borate compounds, (h) azinium compounds, (i) active ester compounds, (j) compounds having carbon-halogen bonds, and (k) pyridium compounds. Polymerization initiators may be added individually or in combination of two or more. The polymerization initiator content is preferably 0.01% to 30% by mass, more preferably 0.05% to 25% by mass, and even more preferably 0.1% to 20% by mass, based on the total mass of the curable compound.

[0020] The polymer film may contain only one curable compound, i.e., only one curable compound A, or it may contain two or more curable compounds. Furthermore, the polymer film may contain only one type of curable compound A, or it may contain two or more types. The content of the curable compound in the polymer film is preferably 0.1% to 70% by mass, more preferably 1% to 60% by mass, even more preferably 5% to 60% by mass, and particularly preferably 10% to 55% by mass, based on the total mass of the polymer film, from the viewpoint of the dielectric loss tangent of the polymer film and the ability to suppress wiring distortion. Furthermore, from the viewpoint of the dielectric loss tangent of the polymer film and the ability to suppress wiring distortion, the content of curable compound A in the polymer film is preferably 0.1% to 70% by mass, more preferably 1% to 60% by mass, even more preferably 5% to 60% by mass, and particularly preferably 10% to 55% by mass, based on the total mass of the polymer film.

[0021] Furthermore, from the viewpoint of suppressing wiring distortion, the content of the curable compound A in the polymer film is preferably 30% to 100% by mass, more preferably 50% to 100% by mass, and particularly preferably 70% to 100% by mass, based on the total mass of the curable compound.

[0022] <Polymers with a dielectric loss tangent of 0.01 or less> A first embodiment of the polymer film according to this disclosure includes a polymer having a dielectric loss tangent of 0.01 or less. The dielectric loss tangent of a polymer having a dielectric loss tangent of 0.01 or less is preferably 0.005 or less, more preferably 0.004 or less, and particularly preferably greater than 0 and 0.003 or less, from the viewpoint of the dielectric loss tangent of the polymer film and adhesion to metal foil or metal wiring. The polymer having a dielectric loss tangent of 0.01 or less may have a curable group, but it shall be a different compound from the curable compound A described above. The curable compound A preferably has a dielectric loss tangent greater than 0.01, and is preferably not a liquid crystal polymer.

[0023] The dielectric loss tangent in this disclosure shall be measured by the following method. Dielectric constant measurement is performed using the resonant perturbation method at a frequency of 10 GHz. A 10 GHz cavity resonator (CP531, manufactured by Kanto Electronics Applied Development Co., Ltd.) is connected to a network analyzer (E8363B, manufactured by Agilent Technology). A sample of polymer film, polymer, or each layer (width: 2 mm x length: 80 mm) is inserted into the cavity resonator, and the dielectric constant and dielectric loss tangent of the polymer film or each layer are measured from the change in resonant frequency before and after insertion over 96 hours under conditions of 25°C and 60% RH. When measuring each layer of the polymer film described later, unnecessary layers may be scraped off with a razor or the like to prepare an evaluation sample of only the target layer. Furthermore, if it is difficult to extract a single film due to the thinness of the layer, the layer to be measured may be scraped off with a razor or the like, and the resulting powdered sample may be used. The measurement of the dielectric loss tangent of the polymer in this disclosure shall be performed according to the above-described method for measuring the dielectric loss tangent, using a sample of the polymer to be measured in powder form, after identifying or isolating the chemical structure of the polymer constituting each layer.

[0024] For polymers with a dielectric loss tangent of 0.01 or less, the weight-average molecular weight Mw is preferably 1,000 or more, more preferably 2,000 or more, and particularly preferably 5,000 or more. Furthermore, for polymers with a dielectric loss tangent of 0.005 or less, the weight-average molecular weight Mw is preferably 1,000,000 or less, more preferably 300,000 or less, and particularly preferably less than 100,000.

[0025] The melting point Tm or 5% mass loss temperature Td of a polymer having a dielectric loss tangent of 0.01 or less is preferably 200°C or higher, more preferably 250°C or higher, even more preferably 280°C or higher, and particularly preferably 300°C to 420°C, from the viewpoint of the dielectric loss tangent of the polymer film, adhesion to metal foil or metal wiring, and heat resistance. The melting point Tm in this disclosure shall be measured using a differential scanning calorimetry (DSC) instrument. Specifically, 5 mg of the sample is placed in the DSC measurement pan, and when it is heated from 30°C at 10°C / min in a nitrogen stream, the peak temperature of the endothermic peak that appears is defined as the Tm of the film. Furthermore, the 5% mass loss temperature Td in this disclosure shall be measured using a thermogravimetric analyzer (TGA). Specifically, the weight of the sample placed in the measurement pan is taken as the initial value, and the temperature at which the weight decreases by 5% mass from the initial value due to heating is defined as the 5% mass loss temperature Td.

[0026] The glass transition temperature Tg of a polymer with a dielectric loss tangent of 0.01 or less is preferably 150°C or higher, more preferably 200°C or higher, and particularly preferably 200°C or higher and less than 280°C, from the viewpoint of the dielectric loss tangent of the polymer film, adhesion to metal foil or metal wiring, and heat resistance. The glass transition temperature Tg in this disclosure shall be measured using a differential scanning calorimetry (DSC) instrument.

[0027] In this disclosure, the type of polymer having a dielectric loss tangent of 0.01 or less is not particularly limited, and known polymers can be used. Examples of polymers with a dielectric loss tangent of 0.01 or less include thermoplastic resins such as liquid crystal polymers, fluorine-based polymers, polymers of compounds having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond, aromatic polyether ketones, polyolefins, polyamides, polyesters, polyphenylene sulfide, polyether ketones, polycarbonates, polyethersulfones, polyphenylene ethers and their modified products, and polyetherimides; elastomers such as copolymers of glycidyl methacrylate and polyethylene; and thermosetting resins such as phenolic resins, epoxy resins, polyimide resins, and cyanate resins. Among these, from the viewpoint of dielectric loss tangent of the polymer film, adhesion to metal foil or metal wiring, and heat resistance, it is preferable that the polymer be at least one polymer selected from the group consisting of liquid crystal polymers, fluoropolymers, polymers of compounds having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond, and aromatic polyether ketones. More preferably, it is at least one polymer selected from the group consisting of liquid crystal polymers and fluoropolymers. From the viewpoint of dielectric loss tangent of the polymer film, liquid crystal polymers are particularly preferred, and from the viewpoint of heat resistance and mechanical strength, fluoropolymers are preferred.

[0028] -Liquid crystal polymer- A second embodiment of the polymer film relating to this disclosure includes a liquid crystal polymer. From the viewpoint of the dielectric loss tangent of the polymer film, polymers with a dielectric loss tangent of 0.01 or less are preferably liquid crystal polymers. The liquid crystal polymer used in this disclosure is not particularly limited in type, and any known liquid crystal polymer can be used. Furthermore, the liquid crystal polymer may be a thermotropic liquid crystal polymer that exhibits liquid crystallinity in a molten state, or a lyotropic liquid crystal polymer that exhibits liquid crystallinity in a solution state. In the case of a thermotropic liquid crystal, it is preferable that it melts at a temperature of 450°C or lower. Examples of liquid crystal polymers include liquid crystal polyester, liquid crystal polyesteramide (in which amide bonds are introduced into liquid crystal polyester), liquid crystal polyester ether (in which ether bonds are introduced into liquid crystal polyester), and liquid crystal polyester (in which carbonate bonds are introduced into liquid crystal polyester). Examples include stercarbonate. Furthermore, from the viewpoint of liquid crystalline properties and coefficient of linear thermal expansion, the liquid crystal polymer is preferably a polymer having an aromatic ring, and more preferably an aromatic polyester or aromatic polyesteramide. Furthermore, the liquid crystal polymer may be a polymer in which an aromatic polyester or aromatic polyesteramide is further modified by introducing isocyanate-derived bonds such as imide bonds, carbodiimide bonds, or isocyanurate bonds. Furthermore, it is preferable that the liquid crystal polymer is a fully aromatic liquid crystal polymer made using only aromatic compounds as raw material monomers.

[0029] Examples of liquid crystal polymers include the following: 1) A compound obtained by polycondensing (i) an aromatic hydroxycarboxylic acid, (ii) an aromatic dicarboxylic acid, and (iii) at least one compound selected from the group consisting of aromatic diols, aromatic hydroxyamines, and aromatic diamines. 2) A compound formed by polycondensation of multiple types of aromatic hydroxycarboxylic acids. 3) A compound obtained by polycondensing (i) an aromatic dicarboxylic acid with (ii) at least one compound selected from the group consisting of aromatic diols, aromatic hydroxyamines, and aromatic diamines. 4) A material obtained by polycondensing (i) a polyester such as polyethylene terephthalate and (ii) an aromatic hydroxycarboxylic acid. Here, aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, aromatic hydroxyamine, and aromatic diamine may each be independently replaced with polycondensable derivatives.

[0030] For example, aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid esters and aromatic dicarboxylic acid esters by converting the carboxyl group to an alkoxycarbonyl group or an aryloxycarbonyl group. By converting the carboxyl group to a haloformyl group, aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid halogens and aromatic dicarboxylic acid halogens. By converting the carboxyl group to an acyloxycarbonyl group, aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid anhydrides and aromatic dicarboxylic acid anhydrides. Examples of polymerizable derivatives of compounds having a hydroxyl group, such as aromatic hydroxycarboxylic acids, aromatic diols, and aromatic hydroxyamines, include those obtained by acyling the hydroxyl group to convert it into an acyloxy group (acylated compounds). For example, by acyling a hydroxyl group to convert it into an acyloxy group, aromatic hydroxycarboxylic acids, aromatic diols, and aromatic hydroxyamines can be replaced with acylated compounds, respectively. Examples of polymerizable derivatives of compounds having an amino group, such as aromatic hydroxyamines and aromatic diamines, include those obtained by acyling the amino group to convert it into an acylamino group (acylated compounds). For example, aromatic hydroxyamines and aromatic diamines can be replaced with acylated products by acyling the amino group to convert it into an acylamino group.

[0031] From the viewpoint of liquid crystalline properties, dielectric loss tangent of the polymer film, and adhesion to the metal layer, the liquid crystal polymer preferably has a constituent unit represented by any of the following formulas (1) to (3) (hereinafter, the constituent unit represented by formula (1), etc. may be referred to as constituent unit (1), etc.), more preferably has a constituent unit represented by formula (1), and particularly preferably has a constituent unit represented by formula (1), a constituent unit represented by formula (2), and a constituent unit represented by formula (3). Equation (1) -O-Ar 1 -CO- Equation (2) -CO-Ar 2 -CO- Equation (3) -X-Ar 3 -Y- In formulas (1) to (3), Ar 1 represents a phenylene group, a naphthylene group, or a biphenylylene group, and Ar 2 and Ar 3 Each of the following independently represents a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by formula (4) below, and X and Y each independently represent an oxygen atom or an imino group, and Ar 1 ~Ar 3 Each hydrogen atom in may be independently substituted with a halogen atom, an alkyl group, or an aryl group. Equation (4) -Ar 4 -Z-Ar 5 - In formula (4), Ar 4 and Ar 5 Each of these independently represents either a phenylene group or a naphthylene group, and Z represents either an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group.

[0032] Examples of the halogen atoms mentioned above include fluorine, chlorine, bromine, and iodine atoms. Examples of the alkyl groups mentioned above include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-hexyl, 2-ethylhexyl, n-octyl, and n-decyl groups. The number of carbon atoms in the alkyl groups is preferably 1 to 10. Examples of the aryl group mentioned above include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group. The number of carbon atoms in the aryl group is preferably 6 to 20. If the above hydrogen atoms are substituted with these groups, the number of substitutions is: Ar 1 Ar 2 Or Ar 3 In each case, there are preferably two or fewer, and more preferably one, independently.

[0033] Examples of the alkylene group mentioned above include a methylene group, a 1,1-ethanediyl group, a 1-methyl-1,1-ethanediyl group, a 1,1-butanediyl group, and a 2-ethyl-1,1-hexanediyl group. The number of carbon atoms in the alkylene group is preferably 1 to 10.

[0034] The constituent unit (1) is a constituent unit derived from an aromatic hydroxycarboxylic acid. The constituent unit (1) is Ar 1 Embodiments in which is a p-phenylene group (constituent unit derived from p-hydroxyammonium acid), and Ar 1 A preferred embodiment is one in which the group is a 2,6-naphthylene group (a constituent unit derived from 6-hydroxy-2-naphthoic acid), or a preferred embodiment is one in which the group is a 4,4'-biphenylylene group (a constituent unit derived from 4'-hydroxy-4-biphenylcarboxylic acid).

[0035] The constituent unit (2) is a constituent unit derived from an aromatic dicarboxylic acid. The constituent unit (2) is Ar 2 A form in which the group is a p-phenylene group (a constituent unit derived from terephthalic acid), Ar 2 A form in which is an m-phenylene group (a constituent unit derived from isophthalic acid), Ar 2Embodiments in which is a 2,6-naphthylene group (a constituent unit derived from 2,6-naphthalenedicarboxylic acid), or Ar 2 An embodiment in which is a diphenyl ether-4,4'-diyl group (a constituent unit derived from diphenyl ether-4,4'-dicarboxylic acid) is preferred.

[0036] The constituent unit (3) is a constituent unit derived from an aromatic diol, an aromatic hydroxylamine, or an aromatic diamine. The constituent unit (3) is Ar 3 Embodiments in which is a p-phenylene group (constituent unit derived from hydroquinone, p-aminophenol, or p-phenylenediamine), Ar 3 A form in which is an m-phenylene group (a constituent unit derived from isophthalic acid), or Ar 3 An embodiment in which is a 4,4'-biphenylylene group (a constituent unit derived from 4,4'-dihydroxybiphenyl, 4-amino-4'-hydroxybiphenyl, or 4,4'-diaminobiphenyl) is preferred.

[0037] The content of constituent unit (1) is preferably 30 mol% or more, more preferably 30 mol% to 80 mol%, even more preferably 30 mol% to 60 mol%, and particularly preferably 30 mol% to 40 mol%, relative to the total amount of all constituent units (the amount of substance equivalent (moles) of each constituent unit, obtained by dividing the mass of each constituent unit constituting the liquid crystal polymer (also called a "monomer unit") by the formula weight of that constituent unit, and then summing them up). The content of constituent unit (2) is preferably 35 mol% or less, more preferably 10 mol% to 35 mol%, even more preferably 20 mol% to 35 mol%, and particularly preferably 30 mol% to 35 mol%, relative to the total amount of all constituent units. The content of constituent unit (3) is preferably 35 mol% or less, more preferably 10 mol% to 35 mol%, even more preferably 20 mol% to 35 mol%, and particularly preferably 30 mol% to 35 mol%, relative to the total amount of all constituent units. The higher the content of constituent unit (1), the easier it is to improve heat resistance, strength, and rigidity, but if it is too high, the solubility in the solvent tends to decrease.

[0038] The ratio of the content of constituent unit (2) to the content of constituent unit (3) is expressed as [content of constituent unit (2)] / [content of constituent unit (3)] (moles / moles), and is preferably 0.9 / 1 to 1 / 0.9, more preferably 0.95 / 1 to 1 / 0.95, and even more preferably 0.98 / 1 to 1 / 0.98.

[0039] Furthermore, the liquid crystal polymer may have two or more of each of the constituent units (1) to (3) independently. In addition, the liquid crystal polymer may have constituent units other than constituent units (1) to (3), but the content of these other units is preferably 10 mol% or less, more preferably 5 mol% or less, relative to the total amount of all constituent units.

[0040] From the viewpoint of solubility in solvents, the liquid crystal polymer preferably has a constituent unit (3) in which at least one of X and Y is an imino group, that is, the constituent unit (3) preferably has at least one of a constituent unit derived from an aromatic hydroxylamine and a constituent unit derived from an aromatic diamine, and more preferably has only a constituent unit (3) in which at least one of X and Y is an imino group.

[0041] Liquid crystal polymers are preferably produced by melt polymerization of raw material monomers corresponding to the constituent units of the liquid crystal polymer. Melt polymerization may be carried out in the presence of a catalyst. Examples of catalysts include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, and nitrogen-containing heterocyclic compounds such as 4-(dimethylamino)pyridine and 1-methylimidazole, with nitrogen-containing heterocyclic compounds being preferred. If necessary, melt polymerization may be further carried out by solid-phase polymerization.

[0042] The lower limit of the liquid crystal polymer's flow initiation temperature is preferably 180°C or higher, more preferably 200°C or higher, and even more preferably 250°C or higher. The upper limit of the flow initiation temperature is preferably 350°C, more preferably 330°C, and even more preferably 300°C. When the liquid crystal polymer's flow initiation temperature is within the above range, it exhibits excellent solubility, heat resistance, strength, and rigidity, and the viscosity of the solution is appropriate.

[0043] The flow start temperature, also called the flow temperature or fluid temperature, is measured using a capillary rheometer at 9.8 MPa (100 kg / cm²). 2 This temperature, when a liquid crystal polymer is melted under a load and heated at a rate of 4°C / min, and extruded from a nozzle with an inner diameter of 1 mm and a length of 10 mm, exhibits a viscosity of 4,800 Pa·s (48,000 poise), and serves as an indicator of the molecular weight of the liquid crystal polymer (see Naoyuki Koide (ed.), "Liquid Crystal Polymers - Synthesis, Molding, and Applications," CMC Corporation, June 5, 1987, p. 95).

[0044] Furthermore, the weight-average molecular weight of the liquid crystal polymer is preferably 1,000,000 or less, more preferably 3,000 to 300,000, even more preferably 5,000 to 100,000, and particularly preferably 5,000 to 30,000. When the weight-average molecular weight of the liquid crystal polymer is within the above range, the heat-treated film exhibits excellent thermal conductivity in the thickness direction, heat resistance, strength, and rigidity.

[0045] -Fluorine-based polymers- Polymers with a dielectric loss tangent of 0.01 or less are preferably fluorine-based polymers from the viewpoint of heat resistance and mechanical strength. In this disclosure, the fluorine-based polymer used as a polymer with a dielectric loss tangent of 0.01 or less is not particularly limited in type, as long as the dielectric loss tangent is 0.01 or less, and any known fluorine-based polymer can be used. Examples of fluorine-based polymers include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, perfluoroalkoxy fluororesins, tetrafluoroethylene / hexafluoropropylene copolymers, ethylene / tetrafluoroethylene copolymers, and ethylene / chlorotrifluoroethylene copolymers. Among these, polytetrafluoroethylene is particularly preferred.

[0046] Furthermore, fluorinated polymers include homopolymers and copolymers comprising fluorinated α-olefin monomers, i.e., α-olefin monomers containing at least one fluorine atom, and, if necessary, non-fluorinated ethylenically unsaturated monomers reactive with fluorinated α-olefin monomers. Examples of fluorinated α-olefin monomers include CF2=CF2, CHF=CF2, CH2=CF2, CHCl=CHF, CClF=CF2, CCl2=CF2, CClF=CClF, CHF=CCl2, CH2=CClF, CCl2=CClF, CF3CF=CF2, CF3CF=CHF, CF3CH=CF2, CF3CH=CH2, CHF2CH=CHF, CF3CF=CF2, and perfluoro(alkyl with 2 to 8 carbon atoms) vinyl ethers (e.g., perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, perfluorooctyl vinyl ether). Among these, at least one monomer selected from the group consisting of tetrafluoroethylene (CF2=CF2), chlorotrifluoroethylene (CClF=CF2), (perfluorobutyl)ethylene, vinylidene fluoride (CH2=CF2), and hexafluoropropylene (CF2=CFCF3) is preferred. Examples of non-fluorinated monoethylenically unsaturated monomers include ethylene, propylene, butene, and ethylenically unsaturated aromatic monomers (e.g., styrene and α-methylstyrene). Fluorinated α-olefin monomers may be used individually or in combination of two or more. Furthermore, non-fluorinated ethylenically unsaturated monomers may be used individually or in combination of two or more.

[0047] Examples of fluorinated polymers include polychlorotrifluoroethylene (PCTFE), poly(chlorotrifluoroethylene-propylene), poly(ethylene-tetrafluoroethylene) (ETFE), poly(ethylene-chlorotrifluoroethylene) (ECTFE), poly(hexafluoropropylene), poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene-ethylene-propylene), poly(tetrafluoroethylene-hexafluoropropylene) (FEP), poly(tetrafluoroethylene-propylene) (FEPM), poly(tetrafluoroethylene-perfluoropropylene vinyl ether), poly(tetrafluoroethylene-perfluoroalkyl vinyl ether) (PFA) (for example, poly(tetrafluoroethylene-perfluoropropyl vinyl ether)), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-chlorotrifluoroethylene), perfluoropolyether, perfluorosulfonic acid, and perfluoropolyoxetane. Fluorine-based polymers may be used individually or in combination of two or more types.

[0048] The fluorine-based polymer is preferably at least one of FEP, PFA, ETFE, or PTFE. FEP is available from DuPont under the trade name TEFLON® FEP, or from Daikin Industries, Ltd. under the trade name NEOFLON FEP; PFA is available from Daikin Industries, Ltd. under the trade name NEOFLON PFA, from DuPont under the trade name TEFLON® PFA, or from Solvay Solexis under the trade name HYFLON PFA.

[0049] The fluorine-based polymer preferably contains PTFE. The PTFE may include a PTFE homopolymer, a partially modified PTFE homopolymer, or a combination of one or both of these. The partially modified PTFE homopolymer preferably contains less than 1% by mass of constituent units derived from comonomers other than tetrafluoroethylene, based on the total mass of the polymer.

[0050] The fluorine-based polymer may be a crosslinkable fluoropolymer having crosslinkable groups. Crosslinkable fluoropolymers can be crosslinked by conventionally known crosslinking methods. One typical crosslinkable fluoropolymer is a fluoropolymer having (meth)acryloxy groups. For example, a crosslinkable fluoropolymer has the formula: H2C = CR'COO - (CH2) n -R-(CH2) n -OOCR'=CH2 It can be expressed as follows, where R is a fluorinated oligomer chain having two or more constituent units derived from a fluorinated α-olefin monomer or a non-fluorinated monoethylenically unsaturated monomer, R' is H or -CH3, and n is 1 to 4. R may be a fluorinated oligomer chain containing constituent units derived from tetrafluoroethylene.

[0051] To initiate a radical crosslinking reaction via (meth)acryloxy groups on a fluorinated polymer, a crosslinked fluoropolymer network structure can be formed by exposing a fluoropolymer having (meth)acryloxy groups to a free radical source. While there are no particular limitations on the free radical source, photoradical polymerization initiators or organic peroxides are preferred. Suitable photoradical polymerization initiators and organic peroxides are well known in the art. Crosslinkable fluoropolymers are commercially available, such as Viton B from DuPont.

[0052] - A polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond - A polymer having a dielectric loss tangent of 0.01 or less may be a polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond. Examples of polymers of compounds having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond include thermoplastic resins having structural units formed from monomers consisting of cyclic olefins such as norbornene or polycyclic norbornene monomers, and these are also called thermoplastic cyclic olefin resins. Polymers of compounds having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond may be ring-opened polymers of the above-mentioned cyclic olefins or hydrogenated ring-opened copolymers using two or more cyclic olefins, or they may be addition polymers of cyclic olefins with aromatic compounds having an ethylenically unsaturated bond, such as chain olefins or vinyl groups. Furthermore, polar groups may be introduced into polymers of compounds having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond. Polymers of compounds having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond may be used individually or in combination of two or more.

[0053] The ring structure of the cyclic aliphatic hydrocarbon group may be a monoring, a fused ring formed by the fusion of two or more rings, or a bridging ring. Examples of ring structures of cyclic aliphatic hydrocarbon groups include cyclopentane rings, cyclohexane rings, cyclooctane rings, isoborone rings, norbornane rings, and dicyclopentane rings. A compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond may be a monofunctional ethylenically unsaturated compound or a polyfunctional ethylenically unsaturated compound. In a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond, the number of cyclic aliphatic hydrocarbon groups may be one or more, or it may be two or more. A polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond may be any polymer obtained by polymerizing a compound having at least one cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond, and may be a polymer of a compound having two or more cyclic aliphatic hydrocarbon groups and groups having an ethylenically unsaturated bond, or it may be a copolymer with another ethylenically unsaturated compound that does not have a cyclic aliphatic hydrocarbon group. Furthermore, the polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond is preferably a cycloolefin polymer.

[0054] -Polyphenylene ether- The polymer having a dielectric loss tangent of 0.01 or less may be a polyphenylene ether. The weight-average molecular weight (Mw) of polyphenylene ether is preferably 500 to 5,000, and more preferably 500 to 3,000, from the viewpoint of heat resistance and film-forming properties, when thermal curing is performed after film formation. When thermal curing is not performed, the Mw is not particularly limited, but is preferably 3,000 to 100,000, and more preferably 5,000 to 50,000. For polyphenylene ethers, the average number of phenolic hydroxyl groups at the molecular ends per molecule (number of terminal hydroxyl groups) is preferably 1 to 5, and more preferably 1.5 to 3, from the viewpoint of dielectric loss tangent and heat resistance. The number of hydroxyl groups or phenolic hydroxyl groups in a polyphenylene ether can be determined, for example, from the product specifications of the polyphenylene ether. Alternatively, the number of terminal hydroxyl groups or terminal phenolic hydroxyl groups can be expressed as a numerical value representing the average number of hydroxyl groups or phenolic hydroxyl groups per molecule of all polyphenylene ether present in one mole of polyphenylene ether. Polyphenylene ethers may be used individually or in combination of two or more types.

[0055] Examples of polyphenylene ethers include polyphenylene ethers composed of 2,6-dimethylphenol and at least one of a difunctional phenol and a trifunctional phenol, or polyphenylene ethers such as poly(2,6-dimethyl-1,4-phenylene oxide) as the main component. More specifically, it is preferable that the compound has a structure represented by formula (PPE).

[0056] [ka]

[0057] In formula (PPE), X represents an alkylene group or single bond having 1 to 3 carbon atoms, m represents an integer from 0 to 20, n represents an integer from 0 to 20, and the sum of m and n represents an integer from 1 to 30. Examples of the alkylene group in X above include a dimethylmethylene group.

[0058] -Aromatic polyether ketone- The polymer having a dielectric loss tangent of 0.01 or less may be an aromatic polyether ketone. The aromatic polyether ketone is not particularly limited, and any known aromatic polyether ketone can be used. The aromatic polyether ketone is preferably a polyether ether ketone. Polyether ether ketones are a type of aromatic polyether ketone, and are polymers in which the bonds are arranged in the order of ether bond, ether bond, and carbonyl bond (ketone). Preferably, each bond is linked by a divalent aromatic group. Aromatic polyether ketones may be used individually or in combination of two or more.

[0059] Examples of aromatic polyetherketones include polyether ether ketone (PEEK) having the chemical structure represented by formula (P1) below, polyether ketone (PEK) having the chemical structure represented by formula (P2) below, polyether ketone ketone (PEKK) having the chemical structure represented by formula (P3) below, polyether ether ketone ketone (PEEKK) having the chemical structure represented by formula (P4) below, and polyether ketone ether ketone ketone (PEKEKK) having the chemical structure represented by formula (P5) below.

[0060] [ka]

[0061] In formulas (P1) to (P5), n is preferably 10 or greater, and more preferably 20 or greater, from the viewpoint of mechanical properties. On the other hand, in terms of easily producing aromatic polyether ketones, n is preferably 5,000 or less, and more preferably 1,000 or less. That is, n is preferably 10 to 5,000, and more preferably 20 to 1,000.

[0062] The polymer having a dielectric loss tangent of 0.01 or less is preferably a polymer that is soluble in a specific organic solvent (hereinafter also referred to as "soluble polymer"). Specifically, the soluble polymer in this disclosure is a polymer that dissolves at 25°C in 0.1 g or more of 100 g of at least one solvent selected from the group consisting of N-methylpyrrolidone, N-ethylpyrrolidone, dichloromethane, dichloroethane, chloroform, N,N-dimethylacetamide, γ-butyrolactone, dimethylformamide, ethylene glycol monobutyl ether, and ethylene glycol monoethyl ether.

[0063] The polymer film may contain only one polymer or two or more polymers, each having a dielectric loss tangent of 0.01 or less. The content of polymers having a dielectric loss tangent of 0.01 or less in the polymer film is preferably 20% to 99% by mass, more preferably 30% to 98% by mass, even more preferably 40% to 97% by mass, and particularly preferably 50% to 95% by mass, based on the total mass of the polymer film, from the viewpoint of the dielectric loss tangent of the polymer film and adhesion to metal foil or metal wiring.

[0064] <Hardening inhibitors> The polymer film according to this disclosure preferably contains a curing inhibitor from the viewpoint of controlling the curing state and suppressing wiring distortion. Examples of curing inhibitors include polymerization inhibitors and heat stabilizers, and known substances can be used for each of these. Polymerization inhibitors include p-methoxyphenol, quinones (e.g., hydroquinone, benzoquinone, methoxybenzoquinone, etc.), phenothiazines, catechols, alkylphenols (e.g., dibutylhydroxytoluene (BHT), etc.), alkylbisphenols, zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionates, mercaptobenzimidazole, phosphites, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (TEMPOL), and tris(N-nitroso-N-phenylhydroxylamine)aluminum salt (also known as cuperone Al). Examples of the above-mentioned heat stabilizers include phosphorus-based heat stabilizers such as tris(2,4-di-tert-butylphenyl) phosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphorous acid, tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4'-diylbisphosphonate, and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, as well as lactone-based heat stabilizers such as reaction products of 8-hydroxy-5,7-di-tert-butylfuran-2-one and o-xylene.

[0065] The hardening inhibitor may be used alone or in combination of two or more types. The content of the curing inhibitor is not particularly limited, but it is preferably 0.0001% to 2.0% by mass relative to the total amount of the polymer film.

[0066] <Filler> The polymer film preferably contains a filler, from the viewpoint of its coefficient of thermal expansion and its adhesion to metal foil or metal wiring. The filler may be particulate or fibrous, and may be inorganic or organic. In the polymer film according to this disclosure, the number density of the filler is preferably greater inside the polymer film than on the surface, from the viewpoint of the coefficient of linear expansion and adhesion to metal foil or metal wiring.

[0067] As the inorganic filler, known inorganic fillers can be used. Examples of inorganic filler materials include BN, Al2O3, AlN, TiO2, SiO2, barium titanate, strontium titanate, aluminum hydroxide, calcium carbonate, and materials containing two or more of these. In particular, as inorganic fillers, metal oxide particles or fibers are preferred from the viewpoint of adhesion to metal foil or metal wiring, silica particles, titania particles, or glass fibers are more preferred, and silica particles or glass fibers are especially preferred.

[0068] The average particle size of the inorganic filler is preferably about 20% to about 40% of the thickness of layer A, for example, a particle size of 25%, 30%, or 35% of the thickness of layer A may be selected. If the particles or fibers are flattened, the length in the short side direction is indicated. Furthermore, from the viewpoint of adhesion to metal foil or metal wiring, the average particle size of the inorganic filler is preferably 5 nm to 20 μm, more preferably 10 nm to 10 μm, even more preferably 20 nm to 1 μm, and particularly preferably 25 nm to 500 nm.

[0069] As the organic filler, known organic fillers can be used. Examples of organic filler materials include polyethylene, polystyrene, urea-formaldehyde filler, polyester, cellulose, acrylic resin, fluororesin, cured epoxy resin, crosslinked benzoguanamine resin, crosslinked acrylic resin, and materials containing two or more of these. Furthermore, the organic filler may be in the form of fibers such as nanofibers, or it may be hollow resin particles. In particular, from the viewpoint of adhesion to metal foil or metal wiring, the organic filler is preferably fluororesin particles, polyester resin particles, or cellulose resin nanofibers, and more preferably polytetrafluoroethylene particles. The average particle size of the organic filler is preferably 5 nm to 20 μm, more preferably 10 nm to 1 μm, even more preferably 20 nm to 500 nm, and particularly preferably 25 nm to 90 nm, from the viewpoint of adhesion to the metal foil or metal wiring.

[0070] The polymer film may contain only one type of filler or two or more types. From the viewpoint of adhesion to metal foil or metal wiring, the filler content in the polymer film is preferably 5% to 80% by volume, more preferably 10% to 70% by volume, even more preferably 15% to 70% by volume, and particularly preferably 20% to 60% by volume, relative to the total volume of the polymer film.

[0071] The polymer film relating to this disclosure preferably has a three-dimensional crosslinked structure from the viewpoint of dielectric loss tangent of the polymer film, adhesion to metal foil or metal wiring, heat resistance, and mechanical strength. One method for forming a three-dimensional crosslinked structure is to polymerize a polyfunctional reactive compound (polyfunctional monomer) to form a cured product of the polyfunctional reactive compound.

[0072] <Other additives> The polymer film may contain other additives besides the components described above. Other known additives can be used. Specifically, examples include leveling agents, defoaming agents, antioxidants, UV absorbers, flame retardants, and colorants.

[0073] Furthermore, the polymer film may also contain other resins as additives, other than polymers and compounds having functional groups, having a dielectric loss tangent of 0.01 or less. Other examples of resins include thermoplastic resins such as polypropylene, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyethersulfone, polyphenylene ether and its modified products, and polyetherimide; elastomers such as copolymers of glycidyl methacrylate and polyethylene; and thermosetting resins such as phenolic resins, epoxy resins, polyimide resins, and cyanate resins.

[0074] The total content of other additives in the polymer film is preferably 25 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, based on the content of 100 parts by mass of polymer having a dielectric loss tangent of 0.01 or less. Furthermore, it is preferable that the total content of other additives in the polymer film is less than the content of compounds having functional groups.

[0075] Furthermore, the polymer film relating to this disclosure may have a multilayer structure. The polymer film according to this disclosure preferably has a layer A and a layer B on at least one side of layer A. From the viewpoint of the dielectric loss tangent of the polymer film and adhesion to metal foil or metal wiring, it is preferable that the polymer film according to this disclosure has a layer A containing a polymer with a dielectric loss tangent of 0.01 or less, and a layer B containing a polymer with a dielectric loss tangent of 0.01 or less and the curable compound A on at least one side of layer A. Layer A may contain only a polymer with a dielectric loss tangent of 0.01 or less, or it may contain a polymer with a dielectric loss tangent of 0.01 or less and a curable compound. Furthermore, layer A may contain the curable compound A mentioned above, but it is preferable that it does not contain it. Furthermore, it is preferable that layer A further contains a filler. Layer B preferably contains a polymer with a dielectric loss tangent of 0.01 or less and the curable compound A, and more preferably is a layer consisting of a polymer with a dielectric loss tangent of 0.01 or less and the curable compound A.

[0076] Furthermore, the polymer film according to this disclosure further comprises a layer C in addition to layers A and B, and it is preferable that the layers B, A and C are arranged in this order. Layer C preferably contains a polymer with a dielectric loss tangent of 0.005 or less and the curable compound A, and more preferably is a layer consisting of a polymer with a dielectric loss tangent of 0.01 or less and the curable compound A.

[0077] The average thickness of layer A is not particularly limited, but from the viewpoint of the dielectric loss tangent of the polymer film and adhesion to metal foil or metal wiring, it is preferably 5 μm to 90 μm, more preferably 10 μm to 70 μm, and particularly preferably 15 μm to 50 μm.

[0078] The method for measuring the average thickness of each layer in the polymer film relating to this disclosure is as follows: The polymer film is cut using a microtome, and the cross-section is observed with an optical microscope to evaluate the thickness of each layer. Three or more cross-sectional samples are cut, and the thickness is measured at three or more points in each cross-section. The average of these measurements is taken as the average thickness.

[0079] The average thickness of layer B and layer C is preferably thinner than the average thickness of layer A, from the viewpoint of the dielectric loss tangent of the polymer film and adhesion to the metal foil or metal wiring. Average thickness T of layer A A and the average thickness T of layer B B T is the ratio ofA / T B The value of is preferably greater than 1, more preferably between 2 and 100, even more preferably between 2.5 and 20, and particularly preferably between 3 and 10, from the viewpoint of the dielectric loss tangent of the polymer film and adhesion to metal foil or metal wiring. Average thickness T of layer A A and the average thickness T of layer C C T is the ratio of A / T C The value of is preferably greater than 1, more preferably between 2 and 100, even more preferably between 2.5 and 20, and particularly preferably between 3 and 10, from the viewpoint of the dielectric loss tangent of the polymer film and adhesion to metal foil or metal wiring. Also, the average thickness T of layer C C and the average thickness T of layer B B T is the ratio of C / T B The value of is preferably 0.2 to 5, more preferably 0.5 to 2, and particularly preferably 0.8 to 1.2, from the viewpoint of the coefficient of linear expansion and adhesion to metal foil or metal wiring. Furthermore, the average thickness of layer B and layer C is preferably 0.1 μm to 20 μm, more preferably 0.5 μm to 15 μm, even more preferably 1 μm to 10 μm, and particularly preferably 3 μm to 8 μm, from the viewpoint of the dielectric loss tangent of the polymer film and adhesion to the metal foil or metal wiring.

[0080] The average thickness of the polymer film relating to this disclosure is preferably 6 μm to 200 μm, more preferably 12 μm to 100 μm, and particularly preferably 20 μm to 60 μm, from the viewpoint of strength, dielectric loss tangent of the polymer film, and adhesion to metal foil or metal wiring.

[0081] The average thickness of the polymer film is measured at five arbitrary locations using an adhesive film thickness gauge, such as an electronic micrometer (product name "KG3001A", manufactured by Anritsu Corporation), and the average of these measurements is used.

[0082] The dielectric loss tangent of the polymer film according to this disclosure is preferably 0.02 or less, more preferably 0.01 or less, even more preferably 0.005 or less, and particularly preferably greater than 0 and 0.003 or less, from the viewpoint of dielectric constant.

[0083] The coefficient of linear expansion of the polymer film according to this disclosure is preferably -20 ppm / K to 50 ppm / K, more preferably -10 ppm / K to 40 ppm / K, even more preferably 0 ppm / K to 35 ppm / K, and particularly preferably 10 ppm / K to 30 ppm / K.

[0084] The method for measuring the coefficient of linear expansion in this disclosure shall be as follows: Using a thermomechanical analyzer (TMA), a tensile load of 1g is applied to both ends of a polymer film or sample of each layer measuring a polymer film with a width of 5mm and a length of 20mm. The temperature is then raised at a rate of 5°C / min from 25°C to 200°C, cooled to 30°C at a rate of 20°C / min, and then heated again at a rate of 5°C / min. The coefficient of linear expansion is calculated from the slope of the TMA curve between 30°C and 150°C. When measuring each layer, you may prepare a measurement sample by scraping off the layer to be measured with a razor or similar tool. Furthermore, if it is difficult to measure the coefficient of linear expansion using the method described above, the following method shall be used for measurement. Section samples are prepared by cutting the film with a microtome and placed in an optical microscope equipped with a heating stage system (HS82, Mettler Toledo). Subsequently, the temperature is increased from 25°C to 200°C at a rate of 5°C / min, then cooled to 30°C at a rate of 20°C / min, and then heated again at a rate of 5°C / min. The thickness of the polymer film or each layer at 30°C (ts30) and the thickness of the polymer film or each layer at 150°C (ts150) are evaluated, and the coefficient of linear expansion of the polymer film or each layer is calculated by dividing the dimensional change by the temperature change ((ts150-ts30) / (150-30)).

[0085] The ratio Es / Ec of the surface modulus Es to the internal modulus Ec of the polymer film at 160°C is preferably 0.05 to 10, more preferably 0.1 to 10, even more preferably 0.1 to 1, and particularly preferably 0.1 to 0.5, from the viewpoint of suppressing wiring distortion. Furthermore, the ratio Es / Ec of the polymer film at 300°C, which is the ratio of the surface modulus Es to the internal modulus Ec, is preferably 0.01 to 10, more preferably 0.05 to 10, even more preferably 0.05 to 1, and particularly preferably 0.05 to 0.5, from the viewpoint of suppressing wiring distortion. Unless otherwise specified, the elastic modulus in this disclosure refers to the storage modulus. Furthermore, in this disclosure, if the polymer film is multilayer, the surface modulus Es is the modulus of the layer present on at least one surface, and is the modulus of the surface with the lower modulus of the two surfaces, and the internal modulus Ec is the modulus of the layer present in the center of the polymer film in the thickness direction. If the polymer film is a single layer, the surface modulus Es is the modulus of the portion within 5 μm from the surface of the polymer film, and is the modulus of the lower of the two surfaces, while the interior modulus Ec is the modulus of the central portion in the thickness direction of the polymer film.

[0086] The loss loss tangent at 160°C in the layer of the polymer film containing the curable compound A is preferably 0.01 or higher, more preferably 0.03 or higher, and particularly preferably 0.05 to 0.2, from the viewpoint of suppressing wiring distortion. Furthermore, from the viewpoint of suppressing wiring distortion, the loss loss tangent at 300°C in the layer of the polymer film containing the curable compound A is preferably 0.03 or higher, more preferably 0.1 or higher, and particularly preferably 0.1 to 0.6.

[0087] The methods for measuring the elastic modulus and loss tangent in this disclosure are shown below. A polymer film is embedded in UV resin, and a sample for cross-sectional evaluation is prepared by cutting it with a microtome. Subsequently, a scanning probe microscope (SPA400, manufactured by SII Nanotechnology Co., Ltd.) is used to observe the sample in VE-AFM mode, and the storage modulus of the surface and interior at the measurement temperature, as well as the loss tangent (loss modulus / storage modulus), are calculated.

[0088] <Method for manufacturing polymer films> [Film forming] The method for manufacturing the polymer film relating to this disclosure is not particularly limited and may refer to known methods. Suitable methods for manufacturing the polymer film according to this disclosure include, for example, casting, coating, and extrusion, with casting being particularly preferred. Furthermore, if the polymer film according to this disclosure has a multilayer structure, suitable methods include, for example, co-casting, multi-layer coating, and co-extrusion. Among these, co-casting is particularly preferred for relatively thin films, while co-extrusion is particularly preferred for thick films. When manufacturing a multilayer structure in a polymer film using co-casting and layer coating methods, it is preferable to use compositions such as a layer A-forming composition, a layer B-forming composition, and a layer C-forming composition, which are obtained by dissolving or dispersing the components of each layer, such as liquid crystal polymer, in a solvent, when performing the co-casting or layer coating method.

[0089] Examples of solvents include halogenated hydrocarbons such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, 1-chlorobutane, chlorobenzene, and o-dichlorobenzene; halogenated phenols such as p-chlorophenol, pentachlorophenol, and pentafluorophenol; ethers such as diethyl ether, tetrahydrofuran, and 1,4-dioxane; ketones such as acetone and cyclohexanone; esters such as ethyl acetate and γ-butyrolactone; and ethylene carbonate. Examples include carbonates such as propyl carbonate; amines such as triethylamine; nitrogen-containing heterocyclic aromatic compounds such as pyridine; nitriles such as acetonitrile and succinonitrile; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethyl sulfoxide and sulfolane; and phosphorus compounds such as hexamethylphosphate and tri-n-butyl phosphate. Two or more of these may be used.

[0090] As a solvent, a solvent mainly composed of aprotic compounds, particularly aprotic compounds without halogen atoms, is preferred due to its low corrosiveness and ease of handling. The proportion of the aprotic compound in the total solvent is preferably 50% to 100% by mass, more preferably 70% to 100% by mass, and particularly preferably 90% to 100% by mass. Furthermore, as the above aprotic compound, it is preferable to use amides such as N,N-dimethylformamide, N,N-dimethylacetamide, tetramethylurea, N-methylpyrrolidone, or esters such as γ-butyrolactone, as they readily dissolve liquid crystal polymers. N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone are more preferred.

[0091] Furthermore, as a solvent, a solvent mainly composed of a compound with a dipole moment of 3 to 5 is preferred because it readily dissolves liquid crystal polymers, and the dipole moment of the solvent as a whole is The proportion of compounds 3 to 5 is preferably 50% to 100% by mass, more preferably 70% to 100% by mass, and particularly preferably 90% to 100% by mass. It is preferable to use a compound with a dipole moment of 3 to 5 as the above-mentioned aprotic compound.

[0092] Furthermore, as a solvent, a solvent mainly composed of a compound with a boiling point of 220°C or less at 1 atmosphere is preferred because it is easy to remove. The proportion of the compound with a boiling point of 220°C or less at 1 atmosphere in the total solvent is preferably 50% to 100% by mass, more preferably 70% to 100% by mass, and particularly preferably 90% to 100% by mass. It is preferable to use a compound with a boiling point of 220°C or lower at 1 atmosphere as the above-mentioned aprotic compound.

[0093] Furthermore, when the polymer film is manufactured by the above-mentioned casting method, co-casting method, coating method, multi-layer coating method, extrusion method, and co-extrusion method, a support may be used. In addition, when a metal layer (metal foil) used in the laminate described later is used as a support, it may be used as is without peeling. Examples of support materials include metal drums, metal bands, glass plates, resin films, or metal foils. Among these, metal drums, metal bands, and resin films are preferred. Examples of resin films include polyimide (PI) films, and commercially available examples include U-Pyrex S and U-Pyrex R manufactured by Ube Industries, Ltd., Kapton manufactured by Toray DuPont, Ltd., and IF30, IF70, and LV300 manufactured by SKC Kolon PI. Furthermore, the support may have a surface treatment layer formed on its surface so that it can be easily peeled off. The surface treatment layer can be made of hard chrome plating, fluororesin, or the like. The average thickness of the resin film support is not particularly limited, but is preferably 25 μm or more and 75 μm or less, and more preferably 50 μm or more and 75 μm or less.

[0094] Furthermore, there are no particular restrictions on the method for removing at least a portion of the solvent from the cast or coated film-like composition (cast film or coating film), and known drying methods can be used.

[0095] [Stretching] The polymer film according to this disclosure can be appropriately combined with stretching in order to control molecular orientation and adjust the coefficient of thermal expansion and mechanical properties. The stretching method is not particularly limited and known methods can be referred to, and may be carried out with a solvent or with a dry film. Stretching with a solvent may be carried out by gripping and stretching the film, or by utilizing auto-shrinkage due to drying without stretching. Stretching is particularly effective for improving elongation at break and tensile strength when film brittleness is reduced by the addition of inorganic fillers, etc.

[0096] Furthermore, the method for producing the polymer film according to this disclosure may include a step of polymerization by light or heat, if necessary. There are no particular restrictions on the means of irradiating light and the means of applying heat; known means of irradiating light, such as metal halide lamps, and known means of applying heat, such as heaters, can be used. There are no particular restrictions on the light irradiation conditions and heat application conditions; they can be carried out at any desired temperature and time, and in a known atmosphere.

[0097] [Heat treatment] The method for producing a polymer film according to this disclosure preferably includes a step of heat treatment (annealing) of the polymer film. The heat treatment temperature in the above heat treatment process is preferably a temperature above the glass transition temperature Tg of a polymer with a dielectric loss tangent of 0.01 or less, or below the melting point Tm, from the viewpoint of the mechanical strength of the web during the manufacturing process and the dimensional change and breaking strength of the manufactured polymer film. Furthermore, the heat treatment temperature in the above heat treatment process is preferably 260°C to 370°C, and more preferably 310°C to 350°C, from the viewpoint of fracture strength. The annealing time is preferably 1 minute to 5 hours, and more preferably 5 minutes to 3 hours. Furthermore, the method for producing a polymer film according to this disclosure may include other known steps as necessary.

[0098] <Application> The polymer film according to this disclosure can be used for various applications, and is particularly suitable for use as a film for electronic components such as printed wiring boards, and is especially suitable for use as a flexible printed circuit board. Furthermore, the polymer film according to this disclosure can be suitably used as a polymer film for metal bonding. Furthermore, the polymer film according to this disclosure can be suitably used as a base film. When used as a base film, the polymer film according to this disclosure preferably has the above-mentioned layer A and layer B. Furthermore, the polymer film according to this disclosure can be suitably used as a bonding sheet (interlayer adhesive sheet). When used as a bonding sheet, the polymer film according to this disclosure preferably has the above layers A, B, and C.

[0099] (Laminated structure) The laminate according to this disclosure may be any laminate in which polymer films according to this disclosure are laminated, but it is preferable that it has a polymer film according to this disclosure and a metal layer or metal wiring disposed on at least one surface of the polymer film, and it is more preferable that it has a polymer film according to this disclosure and a copper layer or copper wiring disposed on at least one surface of the polymer film. Furthermore, the laminate according to this disclosure preferably comprises a metal layer or metal wiring, a polymer film according to this disclosure, and a metal layer or metal wiring in this order, and more preferably comprises a copper layer or copper wiring, a polymer film according to this disclosure, and a copper layer or copper wiring in this order. Furthermore, the laminate according to the present disclosure preferably comprises, in this order, a polymer film according to the present disclosure, a copper layer or copper wiring, a polymer film according to the present disclosure, a metal layer or metal wiring, and a polymer film according to the present disclosure. The two polymer films according to the present disclosure used in the above laminate may be the same or different. The above-mentioned metal layer and metal wiring are not particularly limited and may be any known metal layer and metal wiring, but are preferably, for example, a silver layer, silver wiring, copper layer, or copper wiring, and more preferably a copper layer or copper wiring. Furthermore, the above-mentioned metal layer and metal wiring are preferably metal wiring. Furthermore, the metal in the above-mentioned metal layer and metal wiring is preferably silver or copper, and more preferably copper. Since the polymer film according to this disclosure can be further cured, for example, after a metal layer or metal wiring is attached, the laminate according to this disclosure preferably includes a cured product formed by curing the curable compound A, from the viewpoint of durability. Furthermore, the laminate according to the present disclosure preferably comprises a polymer film having layer B, layer A, and layer C in that order, a metal layer disposed on the layer B side of the polymer film, and a metal layer disposed on the layer C side of the polymer film, and it is more preferable that all of the metal layers are copper layers. The metal layer positioned on the side of layer B is preferably a metal layer positioned on the surface of layer B. The metal layer positioned on the side of layer C is preferably a metal layer positioned on the surface of layer C, the metal layer positioned on the side of layer B is preferably a metal layer positioned on the surface of layer B, and the metal layer positioned on the side of layer C is more preferably a metal layer positioned on the surface of layer C. Furthermore, the metal layer on the side of layer B and the metal layer on the side of layer C may be made of the same material, thickness, and shape, or they may be made of different materials, thicknesses, and shapes. From the viewpoint of adjusting characteristic impedance, the metal layer on the side of layer B and the metal layer on the side of layer C may be made of different materials and thicknesses, and the metal layer may be laminated on only one side of layer B or layer C.

[0100] There are no particular limitations on the method for bonding the polymer film and the metal layer or metal wiring according to this disclosure, and known lamination methods can be used.

[0101] The peel strength between the polymer film and the copper layer is preferably 0.5 kN / m or more, more preferably 0.7 kN / m or more, even more preferably 0.7 kN / m to 2.0 kN / m, and particularly preferably 0.9 kN / m to 1.5 kN / m.

[0102] In this disclosure, the peel strength between the polymer film and the metal layer (e.g., copper layer) shall be measured by the following method. A 1.0 cm wide peel test specimen was prepared from a laminate of a polymer film and a metal layer. The polymer film was fixed to a flat plate with double-sided adhesive tape, and the strength (kN / m) of peeling the polymer film from the metal layer at a speed of 50 mm / min using the 180° method in accordance with JIS C 5016 (1994) was measured.

[0103] The metal layer is preferably a silver layer or a copper layer, and more preferably a copper layer. The copper layer is preferably a rolled copper foil formed by a rolling method, or an electrolytic copper foil formed by an electrolytic method, and more preferably a rolled copper foil from the viewpoint of flexibility.

[0104] The average thickness of the metal layer, preferably the copper layer, is not particularly limited, but is preferably 2 μm to 20 μm, more preferably 3 μm to 18 μm, and even more preferably 5 μm to 12 μm. The copper foil may be a carrier-attached copper foil that is peelably formed on a support (carrier). Known carriers can be used. The average thickness of the carrier is not particularly limited, but is preferably 10 μm to 100 μm, and more preferably 18 μm to 50 μm.

[0105] Furthermore, from the viewpoint of better exhibiting the effects described herein, it is preferable that the metal layer has a group that can interact with the polymer film on the side that is in contact with the polymer film. It is also preferable that the interactable group is a group that corresponds to a functional group of a compound containing a functional group in the polymer film, such as an amino group and an epoxy group, or a hydroxyl group and an epoxy group. Examples of interactable groups include the functional groups listed above in the compounds having the above-mentioned functional groups. In particular, from the viewpoint of adhesion and ease of processing, it is preferable that the group be covalently bondable, more preferably an amino group or a hydroxyl group, and especially preferably an amino group.

[0106] It is also preferable to process the metal layer in the laminate according to this disclosure into a desired circuit pattern by etching, for example, to form a flexible printed circuit board. There are no particular restrictions on the etching method, and known etching methods can be used.

[0107] In the laminate according to this disclosure, the loss loss tangent at 160°C in the layer containing the curable compound A is preferably 0.01 or more, more preferably 0.03 or more, and particularly preferably 0.05 to 0.2, from the viewpoint of suppressing wiring distortion. Furthermore, in the laminate according to this disclosure, the loss loss tangent at 300°C in the layer containing the curable compound A is preferably 0.03 or higher, more preferably 0.1 or higher, and particularly preferably 0.1 to 0.6, from the viewpoint of suppressing wiring distortion. Furthermore, if the polymer film is a single layer, the layer containing the curable compound A becomes the polymer film itself.

[0108] The method for manufacturing the laminate according to this disclosure is not particularly limited, but when performing half-curing, it is preferable to include, for example, a partial curing step in which a polymer film containing a polymer with a dielectric loss tangent of 0.01 or less and a curable compound is cured to form the curable compound A, and a lamination step in which the film is bonded to a copper layer or copper wiring to form a laminate.

[0109] The method for manufacturing a laminate according to this disclosure preferably includes a partial curing step in which a polymer film containing a polymer having a dielectric loss tangent of 0.01 or less and a curable compound is formed by curing a portion of the curable compound A. Furthermore, the method for manufacturing the laminate according to this disclosure preferably includes a partial curing step in which a portion of the curable compound is cured to form the curable compound A in a polymer film containing a liquid crystal polymer and a curable compound. The curing method in the above partial curing step can be appropriately selected depending on the curable compound used, but it is preferable to use a polymerization initiator, and more preferable to use a thermal polymerization initiator. Furthermore, it is preferable to use a curing inhibitor in the above partial curing process. By using a curing inhibitor, the progress of curing can be controlled, and a layer that is only partially cured, so-called B-stage layer, can be easily formed. Furthermore, the polymers, curable compounds, and curable compound A having a dielectric loss tangent of 0.01 or less, as described above, can be suitably used.

[0110] The method for manufacturing a laminate according to this disclosure preferably includes a lamination step in which a metal layer or metal wiring is bonded to the above film to form a laminate. Furthermore, in the bonding process described above, it is preferable to bond metal wiring. There are no particular restrictions on the bonding method in the bonding process described above, and any known lamination method can be used. The bonding pressure in the bonding process described above is not particularly limited, but is preferably 0.1 MPa or higher, and preferably 0.2 MPa to 10 MPa. Furthermore, the bonding temperature in the bonding process described above can be appropriately selected depending on the film used, but it is preferably 150°C or higher, more preferably 280°C or higher, and particularly preferably 280°C to 420°C.

[0111] Furthermore, in the method for manufacturing the laminate according to this disclosure, from the viewpoint of suppressing wiring distortion, the content of the curable compound A after the bonding step is preferably 30% to 100% by mass, more preferably 50% to 100% by mass, and particularly preferably 70% to 100% by mass, based on the total mass of the curable compound.

[0112] Furthermore, the method for manufacturing a laminate according to this disclosure can be suitably used in a method for forming through-holes. Specifically, the method for manufacturing a laminate according to the present disclosure preferably includes, in this order, a preparation step of preparing a polymer film according to the present disclosure, a bonding step of bonding the polymer film to a metal layer or metal wiring to form a laminate, and a through-hole forming step of forming through holes in the layer containing the curable compound A in the laminate.

[0113] There are no particular restrictions on the above preparation process; it is sufficient to prepare the polymer film according to this disclosure. Alternatively, the polymer film according to this disclosure may be manufactured. The bonding process described above is the same as the bonding process described above, and the preferred embodiment is also the same.

[0114] In multilayer printed circuit boards, for example, through-holes are provided for mounting electronic components or for connecting multilayer printed circuits, and conductive plating of a predetermined thickness is applied to these holes. The method for manufacturing a laminate according to this disclosure preferably includes a through-hole formation step of forming through-holes in the layer containing the curable compound A in the laminate. When a layer containing the curable compound A is formed, it is preferable that at least a portion of the surface of the through-hole hardens during the through-hole formation process. Because the inclusion of the above-mentioned curable compound A allows for further curing, at least a portion of the surface of the through-hole can be cured during or after through-hole formation, thereby improving the strength and durability of the through-hole portion. Depending on the through-hole formation conditions, the layer containing the above-mentioned curable compound A can be further cured by the heat and pressure during through-hole formation. There are no particular restrictions on the diameter and shape of the through-hole; they can be selected as appropriate according to the requirements.

[0115] There are no particular restrictions on the method for forming through-holes, and known methods can be used. Examples include methods using lasers or routers, and methods using dry etching. In particular, the method of forming through-holes by laser is preferable because, since heat is generated during through-hole formation, using the polymer film according to this disclosure allows the area near the inner wall surface of the formed through-hole to harden, thereby improving its mechanical strength.

[0116] Furthermore, the method for manufacturing the laminate according to this disclosure preferably includes a post-curing step of curing the curable compound A after the through-hole formation step, from the viewpoint of improving the strength and durability of the through-hole portion. By including the above-mentioned curable compound A, the layer containing the curable compound A can be further cured after through-hole formation, thereby improving strength and durability.

[0117] Furthermore, the method for manufacturing the laminate according to this disclosure may include other known steps. Other processes include, for example, a washing process. [Examples]

[0118] The present disclosure will be further explained with reference to the following examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples may be modified as appropriate, as long as they do not deviate from the spirit of this disclosure. Therefore, the scope of this disclosure is not limited to the following specific examples.

[0119] <<Measurement Method>> [Dielectric loss tangent] The dielectric loss tangent was measured using the resonant perturbation method at a frequency of 10 GHz. A 10 GHz cavity resonator (CP531, manufactured by Kanto Electronics Applied Development Co., Ltd.) was connected to a network analyzer (E8363B, manufactured by Agilent Technology). A film sample (width: 2.0 mm x length: 80 mm) was inserted into the cavity resonator, and the dielectric loss tangent of the film was measured from the change in the resonant frequency before and after insertion over 96 hours under conditions of 25°C and 60% RH.

[0120] [Elastic modulus and loss tangent] Polymer films were embedded in UV-curable resin (UV resin), and samples for cross-sectional evaluation were prepared by cutting with a microtome. Subsequently, observations were made using a scanning probe microscope (SPA400, manufactured by SII Nanotechnology Co., Ltd.) in VE-AFM mode, and the storage modulus of the surface and interior, as well as the loss tangent (loss modulus / storage modulus), at the measurement temperature were calculated.

[0121] [Peel strength] A 10 mm wide peel test specimen was prepared from a laminate of a polymer film and a copper layer. The polymer film was fixed to a flat plate with double-sided adhesive tape, and the strength (kN / m) of the peel when the copper layer was removed from the polymer film at a speed of 50 mm / min using the 180° method in accordance with JIS C 5016 (1994) was measured.

[0122] [Distribution of additive amount in the thickness direction] Samples for cross-sectional evaluation were prepared by cutting the film with a microtome. Subsequently, using a micro-infrared spectroscopy (micro-IR) system, measurements were taken every 2 μm from the surface using a 5 μm × 20 μm aperture. The characteristic absorption spectral intensities derived from the polymer and the curable compound, both with dielectric constants of 0.01 or less, were used to evaluate the content of the curable compound on the surface and inside the polymer film.

[0123] <<Manufacturing Example>> <Liquid crystal polymer> LC-A: Liquid crystal polymer prepared according to the manufacturing method described below.

[0124] -LCA Manufacturing- In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser, 940.9 g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 377.9 g (2.5 mol) of 4-hydroxyacetaminophen, 415.3 g (2.5 mol) of isophthalic acid, and 867.8 g (8.4 mol) of acetic anhydride were added. After replacing the gas in the reactor with nitrogen gas, the temperature was raised from room temperature (23°C) to 140°C over 60 minutes while stirring under a nitrogen gas stream, and then refluxed at 140°C for 3 hours. Next, while distilling off the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150°C to 300°C over 5 hours, and held at 300°C for 30 minutes. After that, the contents were removed from the reactor and cooled to room temperature. The obtained solid was pulverized to obtain powdered liquid crystal polyester (A1). The flow initiation temperature of this liquid crystal polyester (A1) was 193.3°C.

[0125] The liquid crystal polyester (A1) obtained above was heated in a nitrogen atmosphere from room temperature to 160°C over 2 hours and 20 minutes, then heated from 160°C to 180°C over 3 hours and 20 minutes, and held at 180°C for 5 hours to undergo solid-phase polymerization. After cooling, it was pulverized in a pulverizer to obtain powdered liquid crystal polyester (A2). The flow initiation temperature of this liquid crystal polyester (A2) was 220°C.

[0126] The liquid crystal polyester (A2) obtained above was heated in a nitrogen atmosphere from room temperature (23°C) to 180°C over 1 hour and 25 minutes, then heated from 180°C to 255°C over 6 hours and 40 minutes, and held at 255°C for 5 hours to undergo solid-phase polymerization. After cooling, powdered liquid crystal polyester (A) (LC-A) was obtained. The flow initiation temperature of liquid crystal polyester (A) was 302°C. Furthermore, the melting point Tm of this liquid crystal polyester (A) was measured using a differential scanning calorimetry analyzer and was found to be 311°C.

[0127] LC-B: Liquid crystal polymer prepared according to the manufacturing method described below.

[0128] -LCB Manufacturing- In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser, 940.9 g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 377.9 g (2.5 mol) of 4-hydroxyacetaminophen, 415.3 g (2.5 mol) of isophthalic acid, and 867.8 g (8.4 mol) of acetic anhydride were added. After replacing the gas in the reactor with nitrogen gas, the temperature was raised from room temperature (23°C) to 143°C over 60 minutes while stirring under a nitrogen gas stream, and then refluxed at 143°C for 1 hour. Next, while distilling off the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150°C to 300°C over 5 hours, and held at 300°C for 30 minutes. After that, the contents were removed from the reactor and cooled to room temperature. The resulting solid was pulverized to obtain powdered liquid crystal polyester (B1).

[0129] The liquid crystal polyester (B1) obtained above was heated in a nitrogen atmosphere from room temperature to 160°C over 2 hours and 20 minutes, then heated from 160°C to 180°C over 3 hours and 20 minutes, and held at 180°C for 5 hours to undergo solid-phase polymerization. After cooling, it was then pulverized in a pulverizer to obtain powdered liquid crystal polyester (B2).

[0130] The liquid crystal polyester (B2) obtained above was heated in a nitrogen atmosphere from room temperature (23°C) to 180°C over 1 hour and 20 minutes, then heated from 180°C to 240°C over 5 hours, and held at 240°C for 5 hours to undergo solid-phase polymerization. After cooling, powdered liquid crystal polyester (C) (LC-B) was obtained.

[0131] <Curable compound> M-1: A commercially available low-dielectric adhesive (SLK varnish, manufactured by Shin-Etsu Chemical Co., Ltd., mainly containing polymer-type curable compounds, was used so that the solid content was as shown in Table 1.) M-2: A commercially available aminophenol-type epoxy resin (jER630LSD, manufactured by Mitsubishi Chemical Corporation) was used, with a solid content equal to the amount shown in Table 1.

[0132] <Filler> F-1: Commercially available hydrophobic silica with an average primary particle size of 20 nm (NX90S (surface treated with hexamethyldisilazane, manufactured by Nippon Aerosil Co., Ltd.) was used, and the amount of solid content was as shown in Table 1.)

[0133] F-2: Liquid crystal polymer particles prepared according to the manufacturing method described below.

[0134] -LC-C manufacturing- In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser, 1034.99 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 378.33 g (1.75 mol) of 2,6-naphthalenedicarboxylic acid, 83.07 g (0.5 mol) of terephthalic acid, 272.52 g (2.475 mol, 0.225 mol excess of the total molar amount of 2,6-naphthalenedicarboxylic acid and terephthalic acid), 1226.87 g (12 mol) of acetic anhydride, and 0.17 g of 1-methylimidazole as a catalyst were added. After replacing the gas in the reactor with nitrogen gas, the temperature was raised from room temperature to 145°C over 15 minutes while stirring under a nitrogen gas stream, and then refluxed at 145°C for 1 hour.

[0135] Next, while distilling off the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 145°C to 310°C over 3 hours and 30 minutes, and held at 310°C for 3 hours. After that, the solid liquid crystal polyester (LC-C) was extracted and cooled to room temperature. The flow initiation temperature of this polyester (LC-C) was 265°C.

[0136] [Manufacturing of liquid crystal polyester particles (F-1)] Liquid crystal polyester (LC-C) was pulverized using a jet mill (KJ-200, manufactured by Kurimoto Iron Works Co., Ltd.) to obtain liquid crystal polyester particles (F-2). The average particle size of these liquid crystal polyester particles was 9 μm.

[0137] F-3: Commercially available silica particles (SO-C2, manufactured by Admatex Co., Ltd.) with an average particle size of 0.5 μm were used, with the solid content being as shown in Table 1. F-4: Commercially available hollow powder with an average particle size of 16 μm (Glass Bubbles iM30K, manufactured by 3M Japan Ltd.) F-5: Boron nitride particles (melting point > 500°C, HP40MF100 (manufactured by Mizushima Iron Alloy Co., Ltd.), dielectric loss tangent 0.0007)

[0138] <Film forming> The film was formed according to the casting procedure described below.

[0139] [Co-casting A (solution casting)] -Preparation of polymer solutions- The above-mentioned liquid crystal polymer and additives were added to N-methylpyrrolidone and stirred under a nitrogen atmosphere at 140°C for 4 hours to dissolve. Then, the additives were added in the volume ratios shown in Table 1, and the mixture was stirred at 25°C for 30 minutes to obtain the polymer solution. The liquid crystal polymer and additives were added in the volume ratios shown in Table 1, and the solid content concentration was 23% by mass for the solution for layer A (core layer) and 20% by mass for the solution for layer B (surface layer). Next, the polymer solutions were obtained by first passing them through a sintered fiber metal filter with a nominal pore size of 10 μm, and then through another sintered fiber metal filter with the same nominal pore size of 10 μm. If the additive did not dissolve in N-methylpyrrolidone, the polymer solution was prepared without the additive, passed through the sintered fiber metal filter, and then the additive was added and stirred.

[0140] - Fabrication of single-sided copper-clad laminated boards - The obtained polymer solutions for layer A and layer B were fed into a casting die equipped with a feed block adjusted for co-casting of two layers, and cast onto the treated surface of copper foil (Fukuda Metal Foil & Powder Industry Co., Ltd., CF-T4X-SV-12, average thickness 12 μm) so that the copper foil and layer A were in contact. By drying at 40°C for 4 hours, the solvent was removed from the cast film, and a laminate (single-sided copper-clad laminate) having a copper layer and a film was obtained.

[0141] [Co-casting B (solution casting)] -Preparation of polymer solutions- The polymers and additives listed in Table 1 were added to N-methylpyrrolidone and stirred under a nitrogen atmosphere at 140°C for 4 hours to obtain a polymer solution. The polymers and additives were added in the volume ratios listed in Table 1, and the solid content concentration was as shown in Table 1. Next, the polymer solution for layer A, layer B, and, if necessary, layer C was obtained by first passing the mixture through a sintered fiber metal filter with a nominal pore size of 10 μm, and then again through another sintered fiber metal filter with the same nominal pore size of 10 μm. If the additive does not dissolve in N-methylpyrrolidone, a liquid crystal polymer solution is prepared without the additive, passed through the sintered fiber metal filter, and then the additive is added and the mixture is stirred at 25°C for 30 minutes.

[0142] -Film Production- The obtained polymer solutions for layer A and layer B, and optionally for layer C, were fed into a casting die equipped with a feed block adjusted for co-casting. These solutions were then cast onto a treated surface of copper foil (Fukuda Metal Foil & Powder Industry Co., Ltd., CF-T9DA-SV-18, 18 μm thick, surface roughness Rz 0.85 μm of the bonding surface (treated surface)) to produce laminates of layer B / layer A( / layer C) / copper foil. The solvent was removed from the cast film by drying at 40°C for 4 hours, and then at 100°C for 2 hours, yielding polymer films (laminateds) having copper layers.

[0143] [Single-layer casting (solution-based film formation)] -Preparation of polymer solutions- The above-mentioned liquid crystal polymer and additives were added to N-methylpyrrolidone and stirred under a nitrogen atmosphere at 140°C for 4 hours to dissolve. Then, the additives were added in the volume ratios shown in Table 1, and the mixture was stirred at 25°C for 30 minutes to obtain a polymer solution. The liquid crystal polymer and additives were added in the volume ratios shown in Table 1, and the solid content concentration was 23% by mass. Next, the polymer solutions were obtained by first passing them through a sintered fiber metal filter with a nominal pore size of 10 μm, and then through another sintered fiber metal filter with the same nominal pore size of 10 μm. If the additive did not dissolve in N-methylpyrrolidone, the liquid crystal polymer solution was prepared without the additive, passed through the sintered fiber metal filter, and then the additive was added and stirred.

[0144] -Preparation of polymer films- The obtained polymer solution was transferred to a single-layer casting die and cast onto a stainless steel belt. When the residual solvent content reached 25% by mass, it was peeled off the support, and the solvent was removed by drying while gripping both ends of the web with tenter clips to obtain a polymer film.

[0145] - Fabrication of single-sided copper-clad laminated boards - The obtained polymer film was placed on top of a copper foil (Fukuda Metal Foil & Powder Industry Co., Ltd., CF-T4X-SV-12, average thickness 12 μm) so that the treated surface was in contact with the film. Lamination was performed for 1 minute at 140°C and a lamination pressure of 0.4 MPa using a laminator (Nikko Materials Co., Ltd. "Vacuum Laminator V-130") to obtain a single-sided copper-clad laminate.

[0146] - Fabrication of double-sided copper-clad laminated boards - ~Copper-clad laminate precursor process~ The obtained polymer film was laminated on both sides so that the treated side of the copper foil (Fukuda Metal Foil & Powder Industry Co., Ltd., CF-T4X-SV-12, average thickness 12 μm) was in contact with the film. Lamination was then performed for 1 minute at 140°C and a lamination pressure of 0.4 MPa using a laminator (Nikko Materials Co., Ltd., "Vacuum Laminator V-130") to obtain a double-sided copper-clad laminate.

[0147] <Fabrication of Flexible Wiring Boards 1> Using the single-sided copper-clad laminate and the double-sided copper-clad laminate described above, a flexible wiring board having a four-layer stripline structure for the outer layer plane (ground layer) was fabricated.

[0148] - Wiring substrate formation process - Using a known photofabrication technique, the copper foil of a double-sided copper-clad laminate using the film of Comparative Example 1 was patterned to create a wiring substrate containing three pairs of signal lines. The length of the signal lines was set to 100 mm, and the width was set so that the characteristic impedance was 50 Ω.

[0149] -Lamination process- Using the above-mentioned wiring substrate and a pair of the above-mentioned single-sided copper-clad laminates, the layers were stacked in the order of single-sided copper-clad laminate / wiring substrate / single-sided copper-clad laminate, with the film side of the single-sided copper-clad laminate in contact with the wiring substrate. Using a vacuum press, the curable compound was sufficiently cured by pressing the layers together for 60 minutes at the temperature and 4.5 MPa conditions listed in Table 1, thereby fabricating a flexible wiring substrate.

[0150] We evaluated the wiring distortion using the fabricated flexible wiring board. The evaluation method is as follows. The evaluation results are shown in Table 1.

[0151] <Wiring distortion> Flexible wiring boards were cut using a microtome, and the cross-sections were observed with an optical microscope. The ability to suppress wiring distortion was then evaluated based on the following evaluation criteria. A: No distortion was detected in the signal lines or ground lines. B: No distortion is observed in the signal line, but distortion is observed in the ground line. C: Distortion is observed in one pair of signal lines. D: Distortion is observed in 2-pair or 3-pair signal lines.

[0152] [Table 1]

[0153] As shown in Table 1, in Examples 1 to 9, the dielectric loss tangent was 0.01 or less, and it was found that wiring distortion was suppressed due to excellent surface irregularity tracking capabilities. Furthermore, the flexible wiring boards of Examples 1 to 4 exhibited excellent durability because the curing reaction was sufficiently carried out during the lamination process. On the other hand, when using the single-sided copper-clad laminate of Comparative Example 1, it was found that the ability to follow surface irregularities was inferior, resulting in wiring distortion. Furthermore, the polymer film of Example 4 was used for the evaluation of through-hole processability described later, and the polymer film of Example 5 was used for the evaluation of film lamination described later, without performing the wiring distortion evaluation described above.

[0154] <Evaluation of through-hole machinability> In Example 4, through-holes were drilled into a double-sided copper-clad laminate using the polymer film, followed by conductive treatment and electroplating to form a 20 μm thick plating layer, thereby ensuring interlayer conductivity between both sides of the substrate. Furthermore, signal lines and ground pads were formed using a known photographic technique, and then coverlays containing a 12.5 μm thick polyimide film were formed on both sides. The same processing was also performed on a double-sided copper-clad laminate using the film of Comparative Example 1.

[0155] The through-hole portions of the obtained laminate were cut with a microtome, and the surface roughness Rz of the through-hole plating was observed using a scanning electron microscope. When the film of Comparative Example 1 was used, the surface roughness was 5 μm, while the film of Example 4 was 1 μm, which was much better.

[0156] <Evaluation of film lamination> A commercially available liquid crystal polymer film (Vecter CTQ, manufactured by Kuraray Co., Ltd.) was sandwiched between two polymer films from Example 5. A copper foil (Fukuda Metal Foil & Powder Industry Co., Ltd., CF-T9DA-SV-12, average thickness 12 μm) was then placed on the outside so that its treated surface was in contact with the film. Lamination was performed for 1 minute at 140°C and a lamination pressure of 0.4 MPa using a laminator (V-130 vacuum laminator, manufactured by Nikko Materials Co., Ltd.) to obtain a precursor of a double-sided copper-clad laminate.

[0157] Next, using a thermocompression press (MP-SNL, manufactured by Toyo Seiki Seisakusho Co., Ltd.), the obtained copper-clad laminate precursor was thermocompressed at 300°C and 4.5 MPa for 10 minutes to produce a double-sided copper-clad laminate.

[0158] The peel strength of the obtained double-sided copper-clad laminate was 9 kN / m, confirming that sufficient strength was ensured.

[0159] The disclosure of Japanese Patent Application No. 2020-211785, filed on 21 December 2020, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted as being incorporated by reference.

Claims

1. A polymer having a dielectric loss tangent of 0.01 or less, and Contains a curable compound, The curable compound includes curable compound A, which is an oligomer or polymer. It is a polymer film, The ratio Es / Ec of the surface modulus Es to the internal modulus Ec of the polymer film at 160°C is 0.1 to 0.

5. A polymer film having a multilayer structure, wherein the surface modulus Es is the modulus of the layer present on at least one surface and the modulus of the surface with the lower modulus of elasticity among the two surfaces, and the internal modulus Ec is the modulus of the layer present in the center of the polymer film in the thickness direction.

2. Liquid crystal polymer, and Contains a curable compound, The curable compound includes curable compound A, which is an oligomer or polymer. It is a polymer film, The ratio Es / Ec of the surface modulus Es to the internal modulus Ec of the polymer film at 160°C is 0.1 to 0.

5. A polymer film having a multilayer structure, wherein the surface modulus Es is the modulus of the layer present on at least one surface and the modulus of the surface with the lower modulus of elasticity among the two surfaces, and the internal modulus Ec is the modulus of the layer present in the center of the polymer film in the thickness direction.

3. The polymer film according to claim 1 or claim 2, wherein the content of the curable compound A is greater on the surface of the polymer film than inside the polymer film, where the surface is the smaller of either a range of 3 μm in the depth direction from the outermost surface of the polymer film or a range of 10% or less of the total thickness of the polymer film from the outermost surface, and the interior is the smaller of either a range of ±1.5 μm from the center in the thickness direction of the polymer film or a range of ±5% of the total thickness from the center in the thickness direction of the polymer film.

4. The polymer film according to claim 1, wherein the polymer having a dielectric loss tangent of 0.01 or less is a liquid crystal polymer.

5. The polymer film according to any one of claims 1 to 4, wherein the dielectric loss tangent of the polymer is 0.01 or less, or the melting point Tm or 5% mass loss temperature Td of the liquid crystal polymer is 200°C or higher.

6. The polymer film contains particles, A polymer film according to any one of claims 1 to 5, comprising the curable compound inside or on the surface of the particles.

7. The polymer film according to any one of claims 1 to 6, wherein the polymer film comprises a curing inhibitor.

8. The polymer film according to any one of claims 1 to 7, wherein the polymer having a dielectric loss tangent of 0.01 or less, or the liquid crystal polymer, comprises a liquid crystal polymer having a structural repeating unit represented by any one of formulas (1) to (3). Equation (1) -O-Ar １ -CO- Formula (2) -CO-Ar ２ -CO- Equation (3) -X-Ar ３ -Y- In formulas (1) to (3), Ar １ represents a phenylene group, a naphthylene group, or a biphenylylene group, and Ar ２ and Ar ３ Each of the following independently represents a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4): X and Y each independently represent an oxygen atom or an imino group, and Ar １ ~Ar ３ Each hydrogen atom in may be independently substituted with a halogen atom, an alkyl group, or an aryl group. Formula (4) -Ar ４ -Z-Ar ５ - In formula (4), Ar ４ and Ar ５ Each of these independently represents either a phenylene group or a naphthylene group, and Z represents either an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group.

9. The polymer film according to any one of claims 1 to 8, wherein the content of the curable compound A is 30% by mass to 100% by mass with respect to the total mass of the curable compound.

10. It has a layer A and a layer B provided on at least one surface of the layer A, A polymer film according to claim 1, claim 4, or any one of claims 3 and 5 to 9, which references claim 1, wherein the layer B comprises a polymer having a dielectric loss tangent of 0.01 or less, and the curable compound A.

11. A polymer film according to any one of claims 1 to 10, which is a base film.

12. It further has layer C, A polymer film according to claim 10, or claim 11, which references claim 10, having layer B, layer A, and layer C in this order.

13. A polymer film according to any one of claims 1 to 12, which is a bonding sheet.

14. A laminate comprising a polymer film according to any one of claims 1 to 13, and a metal layer or metal wiring disposed on at least one surface of the polymer film.

15. The laminate according to claim 14, comprising a metal layer or metal wiring, the polymer film, and the metal layer or metal wiring in this order.

16. The laminate according to claim 14 or claim 15, comprising a cured product obtained by curing the curable compound A.

17. A laminate comprising, in this order, a polymer film according to any one of claims 1 to 13, a metal layer or metal wiring, a polymer film according to any one of claims 1 to 13, a metal layer or metal wiring, and a polymer film according to any one of claims 1 to 13.

18. The laminate according to any one of claims 14 to 17, wherein the metal in the metal layer or metal wiring is copper or silver.

19. A polymer film according to any one of claims 1 to 13, comprising a partial curing step of forming a curable compound A which is an oligomer or polymer obtained by curing a part of the curable compound, This process includes, in this order, a lamination step of bonding the aforementioned film to a metal layer or metal wiring to form a laminate. A method for manufacturing laminates.

20. The method for manufacturing a laminate according to claim 19, wherein the bonding pressure in the bonding step is 0.1 MPa or more.

21. The method for producing a laminate according to claim 19 or claim 20, wherein, after the bonding step, the content of the curable compound A is 30% by mass to 100% by mass with respect to the total mass of the curable compound.

22. Preparation steps for preparing a polymer film according to any one of claims 1 to 13, A lamination step of bonding the polymer film and a metal layer or metal wiring to form a laminate, and This step includes forming through-holes in the layer containing the curable compound A in the laminate. A method for manufacturing laminates.

23. The method for manufacturing a laminate according to claim 22, wherein in the through-hole formation step, at least a portion of the surface of the through-hole hardens.

24. A method for manufacturing a laminate according to claim 22 or claim 23, comprising a post-curing step of curing the curable compound A after the through-hole formation step.

25. The method for manufacturing a laminate according to any one of claims 19 to 24, wherein the metal in the metal layer or metal wiring is copper or silver.

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