CN116507670B

CN116507670B - Polymer film and laminate

Info

Publication number: CN116507670B
Application number: CN202180077151.5A
Authority: CN
Inventors: 佐佐田泰行
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2020-11-24
Filing date: 2021-11-24
Publication date: 2024-08-13
Anticipated expiration: 2041-11-24
Also published as: CN116507670A

Abstract

The present invention provides a polymer film having excellent adhesion to a substrate, and a laminate using the polymer film. The polymer film contains a polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group, and the concentration of the compound having a functional group in at least one surface of the polymer film is higher than the concentration of the compound having a functional group in the interior.

Description

Polymer film and laminate

Technical Field

The present invention relates to a polymer film and a laminate.

Background

In recent years, the frequency used in communication devices tends to be very high. In order to suppress transmission loss in a high frequency band, it is required to reduce the relative dielectric constant and dielectric loss tangent of an insulating material used in a circuit board.

Conventionally, polyimide has been widely used as an insulating material for a circuit board, but a liquid crystal polymer having high heat resistance and low water absorption and having a small loss in a high frequency band has been attracting attention.

As a conventional liquid crystal polymer film, for example, patent document 1 describes a liquid crystal polyester film including at least a liquid crystal polyester, wherein when the 1 st degree of orientation is set to the 1 st degree of orientation with respect to the direction 1 parallel to the main surface of the liquid crystal polyester film and the 2 nd degree of orientation is set to the 2 nd degree of orientation with respect to the direction 2 parallel to the main surface and orthogonal to the 1 st direction, the ratio of the 1 st degree of orientation to the 2 nd degree of orientation, i.e., the 1 st degree of orientation/the 2 nd degree of orientation, is 0.95 or more and 1.04 or less, and the 3 rd degree of orientation of the liquid crystal polyester measured by a wide angle X-ray scattering method in the direction parallel to the main surface is 60.0% or more.

As a conventional functional film, a functional film described in patent document 2 is known.

Patent document 2 describes a copolymer comprising a repeating unit represented by the following general formula (I) and a repeating unit represented by the following general formula (II) and/or a functional film containing a crosslinking reactant derived from the copolymer.

[ Chemical formula 1]

In the general formula (I), R ¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R ² represents an alkyl group having 1 to 20 carbon atoms having at least one fluorine atom as a substituent or a group containing-Si (R ^a3)(R^a4) O-, and L represents a divalent linking group composed of at least one selected from the group consisting of-O-, - (c=o) O-, -O (c=o) -, a divalent aliphatic chain group, and a divalent aliphatic cyclic group. R ^a3 and R ^a4 each independently represent an alkyl group having 1 to 12 carbon atoms which may have a substituent.

[ Chemical formula 2]

In the general formula (II), R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R ¹¹ and R ¹² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R ¹¹ and R ¹² may be bonded. X ¹ represents a divalent linking group.

Technical literature of the prior art

Patent literature

Patent document 1: japanese patent laid-open No. 2020-26474

Patent document 2: japanese patent application laid-open No. 2018-5215

Disclosure of Invention

Technical problem to be solved by the invention

The object of the present invention is to provide a polymer film having excellent adhesion to a substrate.

Further, an object of an embodiment of the present invention is to provide a laminate using the polymer film.

Means for solving the technical problems

The method for solving the above-described problems includes the following means.

<1> A polymer film comprising a polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group, wherein the concentration of the compound having a functional group in at least one surface of the polymer film is higher than the concentration of the compound having a functional group in the interior.

<2> A polymer film comprising a polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group, wherein the surface coating ratio of the compound having a functional group on at least one surface of the polymer film is 50 area% or more.

<3> The polymer film according to <1> or <2>, wherein the functional group is at least one selected from the group consisting of a covalently-bondable group, an ionically-bondable group, a hydrogen-bondable group and a dipole-interactable group.

<4> The polymer film according to <3>, wherein the above functional group is a covalently bondable group.

<5> The polymer film according to <4>, wherein the covalently-bondable group is at least one group selected from the group consisting of an epoxy group, an oxetanyl group, an isocyanate group, an acid anhydride group, a carbodiimide group, an N-hydroxy ester group, a glyoxal group, an imide ester group, a haloalkyl group and a thiol group.

<6> The polymer film according to any one of <1> to <5>, wherein the above-mentioned compound having a functional group contains a silicon atom or a fluorine atom.

<7> The polymer film according to any one of <1> to <6>, wherein the polymer film further comprises a third component for fixing the compound having a functional group to the polymer having a dielectric loss tangent of 0.005 or less.

<8> The polymer film according to <7>, wherein the third component comprises a cured product of a polyfunctional reactive compound.

<9> The polymer film according to <7> or <8>, wherein the third component comprises a polymer having a functional group which interacts with the compound having a functional group and is compatible with the polymer having a dielectric loss tangent of 0.005 or less.

<10> The polymer film according to any one of <1> to <9>, wherein a difference between an SP value by the Hoy method of the polymer having a dielectric loss tangent of 0.005 or less and an SP value by the Hoy method of the compound having a functional group is 5MPa ^0.15 or less.

<11> The polymer film according to any one of <1> to <10>, wherein the polymer film has a layer a and a layer B on at least one surface of the layer a, the layer B containing the compound having a functional group.

<12> The polymer film according to <11>, wherein the layer B contains a third component in which the compound having a functional group is fixed to the polymer having a dielectric loss tangent of 0.005 or less.

<13> The polymer film according to <12>, wherein the content of the third component in the layer B is more than the content of the third component in the layer a.

<14> The polymer film according to any one of <11> to <13>, further comprising a layer C, wherein the polymer film comprises the layer B, the layer a, and the layer C in this order.

<15> The polymer film according to any one of <1> to <14>, wherein the linear expansion coefficient of the polymer film is from-20 ppm/K to 50ppm/K.

<16> The polymer film according to any one of <1> to <15>, wherein the dielectric loss tangent of the polymer film is 0.01 or less.

<17> The polymer film according to any one of <1> to <16>, wherein the polymer film contains a filler.

<18> The polymer film according to <17>, wherein the number density of the filler in the polymer film is greater than the number density of the filler in the surface of the polymer film.

<19> The polymer film according to any one of <1> to <18>, wherein the polymer having a dielectric loss tangent of 0.005 or less comprises a liquid crystal polymer.

<20> The polymer film according to <19>, wherein the polymer having a dielectric loss tangent of 0.005 or less comprises a liquid crystal polymer having a structural unit represented by any one of the formulas (1) to (3).

Formula (1) -O-Ar ¹ -CO-

Formula (2) -CO-Ar ² -CO-

Formula (3) -X-Ar3 ^- Y-

In the formulae (1) to (3), ar ¹ represents phenylene, naphthylene or biphenylene, ar ² and Ar ³ each independently represent phenylene, naphthylene, biphenylene or a group represented by the following formula (4), X and Y each independently represent an oxygen atom or an imino group, and a hydrogen atom in Ar ¹～Ar³ may be independently substituted with a halogen atom, an alkyl group or an aryl group.

Formula (4) -Ar ⁴-Z-Ar⁵ -

In the formula (4), ar ⁴ and Ar ⁵ each independently represent 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.

<21> A polymer film comprising a liquid crystal polymer and a compound having a functional group, wherein the concentration of the compound having a functional group in at least one surface is higher than the concentration of the compound having a functional group in the interior.

<22> A polymer film comprising a liquid crystal polymer and a compound having a functional group, wherein the surface coating ratio of the compound having a functional group on at least one surface of the polymer film is 50 area% or more.

<23> A laminate comprising the polymer film according to any one of <1> to <22>, and a metal layer having a higher concentration of the compound having a functional group than the inner surface, the metal layer being disposed in the polymer film.

The laminate of <24> <23>, which has metal layers respectively disposed on both sides of the polymer film.

<25> The laminate according to <23> or <24>, wherein the metal layer is a copper layer, and the peel strength between the polymer film and the copper layer is 0.5kN/m or more.

<26> The laminate according to any one of <23> to <25>, wherein the polymer film has a layer a and a layer B on at least one surface of the layer a, the layer B contains the compound having a functional group, and the metal layer is disposed on the layer B.

Effects of the invention

According to the embodiment of the present invention, a polymer film having excellent adhesion to a substrate can be provided.

Further, according to another embodiment of the present invention, a laminate using the polymer film can be provided.

Detailed Description

Hereinafter, the present invention will be described in detail. The following description of the constituent elements may be made according to the representative embodiments of the present invention, but the present invention is not limited to such embodiments.

In the present specification, "to" representing a numerical range is used in a meaning including values described before and after the numerical range as a lower limit value and an upper limit value.

In the numerical ranges described in stages in the present invention, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the other numerical range described in stages. In the numerical ranges described in the present invention, the upper limit or the lower limit of the numerical range may be replaced with the values shown in the examples.

In the labeling of the group (atomic group) in the present specification, the unsubstituted and substituted labels include a group having no substituent and a group having a substituent. For example, "alkyl" means to include not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

In the present specification, "(meth) acrylic acid" is a term used in a concept including both acrylic acid and methacrylic acid, and "(meth) acryl" is a term used in a concept including both acryl and methacryl.

The term "step" in the present specification is not limited to a single step, but is also included in the term if the desired purpose of the step can be achieved even if the step cannot be clearly distinguished from other steps.

In the present invention, "mass%" and "weight%" are synonymous, and "part by mass" and "part by weight" are synonymous.

In the present invention, a combination of two or more preferred embodiments is a more preferred embodiment.

Unless otherwise specified, the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present invention are molecular weights obtained by detecting the molecular weights using a differential refractometer using PFP (pentafluorophenol)/chloroform=1/2 (mass ratio) as a solvent and converting the molecular weights into polystyrene as a standard substance by using a column of TSKgel SuperHM-H (trade name manufactured by Tosoh Corporation) in a Gel Permeation Chromatography (GPC) analyzer.

(Polymer film)

In the first embodiment of the polymer film according to the present invention, the polymer film contains a polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group, and the concentration of the compound having a functional group on at least one surface is higher than the concentration of the compound having a functional group in the interior.

In a second embodiment of the polymer film according to the present invention, the polymer film contains a polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group, and the surface coating ratio of the compound having a functional group on at least one surface of the polymer film is 50 area% or more.

In a third embodiment of the polymer film according to the present invention, the polymer film contains a liquid crystal polymer and a compound having a functional group, and the concentration of the compound having a functional group on at least one surface is higher than that in the inside.

In a fourth embodiment of the polymer film according to the present invention, the polymer film contains a liquid crystal polymer and a compound having a functional group, and the surface coating ratio of the compound having a functional group on at least one surface of the polymer film is 50 area% or more.

In the present specification, unless otherwise specified, all of the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment will be described in the case of simply called "polymer film according to the present invention" or "polymer film".

Most of the conventional polymer films have a large dielectric loss tangent. In addition, the conventional polymer film has insufficient adhesion between the polymer film having a small dielectric loss tangent and a substrate (for example, a plastic film, a metal foil, or a metal wiring).

As a result of intensive studies, the present inventors have found that by adopting the above-described structure, a polymer film excellent in adhesion to a substrate can be provided.

The detailed mechanism by which the above-described effects can be obtained is not clear, but is presumed as follows.

The polymer having a dielectric loss tangent of 0.005 or less, the liquid crystal polymer, and the compound having a functional group are contained, and it is estimated that the compound having a functional group is present on the surface of the polymer film and interacts with the substrate or a group present on the surface of the substrate, so that the adhesion to the substrate is excellent, even when the polymer having a dielectric loss tangent of 0.005 or less or the liquid crystal polymer is used, because the concentration of the compound having a functional group on at least one surface is higher than that in the interior or the surface coating ratio of the compound having a functional group on at least one surface of the polymer film is 50 area% or more.

Further, although the dielectric loss tangent of the compound having a functional group is relatively high, it is estimated that the total amount of the compound added can be reduced by increasing the concentration of the surface, and a polymer film having a good dielectric loss tangent can be obtained.

In the first and third embodiments of the polymer film according to the present invention, the concentration of the compound having a functional group in at least one surface is higher than that in the interior, and from the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer, the concentration of the compound having a functional group in at least one surface is preferably 2 to 200 times higher than that in the interior, and more preferably the concentration of the compound having a functional group in at least one surface is 5 to 100 times higher than that in the interior.

In the second and fourth embodiments of the polymer film according to the present invention, the concentration of the compound having a functional group in at least one surface is preferably higher than that in the interior, more preferably 2 to 200 times higher than that in the interior, and particularly preferably 5 to 100 times higher than that in the interior, from the viewpoints of the dielectric tangent of the polymer film and the adhesion to the metal layer.

The method for determining the concentration of the compound having a functional group in the polymer film and on the surface of the polymer film in the present invention is as follows.

A cross-section sample in the thickness direction of the polymer film was prepared by cutting the polymer film with a microtome, and the distribution of each component in the thickness direction of the polymer film was measured on the cross-section by time-of-flight secondary ION mass spectrometry (TOF-SIMS, measuring apparatus: TOF-SIMSV manufactured by ION-TOF Co.).

Here, the surface in the polymer film means the outer surface (surface in contact with air or the substrate) of the polymer film, and in the present invention, the "surface" of the polymer film means a region from the outermost surface of the polymer film to a position corresponding to 10% of the thickness of the polymer film when the thickness of the polymer film is 30 μm or less. In the case where the thickness of the polymer film exceeds 30 μm, the "surface" means a region from the outermost surface of the polymer film to a position apart from 3 μm in the thickness direction.

In the present invention, the term "inside" of the polymer film means a region from the center in the thickness direction of the polymer film to a position corresponding to ±5% of the thickness of the polymer film when the thickness of the polymer film is 30 μm or less. When the thickness of the polymer film exceeds 30. Mu.m, the term "inside" means a region from the center in the thickness direction of the polymer film to a position away from + -1.5 μm in the thickness direction.

In the second and fourth embodiments of the polymer film according to the present invention, the surface coating rate of the compound having a functional group on at least one surface of the polymer film is 50 area% or more, and the surface coating rate of the compound having a functional group on at least one surface of the polymer film is preferably 50 area% to 100 area% from the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer.

In the first and third embodiments of the polymer film according to the present invention, the surface coating ratio of the compound having a functional group on at least one surface of the polymer film is preferably 50 area% or more, more preferably 50 area% to 100 area%, and still more preferably 80 area% to 100 area% from the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer.

The surface coverage of the above-mentioned compound having a functional group in the surface of the polymer film in the present invention can be measured by the following method.

A polymer film containing no compound having a functional group and a compound having a functional group are prepared. The contact angle was measured for a polymer film containing no compound having a functional group and a compound having a functional group, and the surface energy was calculated from the contact angle.

Also, the surface energy was calculated for the polymer film as the object of measurement.

A calibration curve is prepared using the surface energy of a polymer film that does not contain a compound having a functional group and the surface energy of a compound having a functional group.

The polymer film containing no compound having a functional group corresponds to a polymer film having a surface coating ratio of 0 area%, and the compound having a functional group corresponds to a polymer film having a surface coating ratio of 100 area%.

From the calibration curve thus prepared, the surface coverage was calculated from the surface energy of the polymer film to be measured.

The surface energy was measured for contact angle with water and diiodomethane after 24 hours of conditioning at 25 ℃ and 60% relative humidity, calculated from the measured contact angle using the method of Owens. The contact angle can be measured using, for example, DM901 (Kyowa INTERFACE SCIENCE co., ltd.

Even when a polymer film containing no compound having a functional group cannot be prepared, image analysis of the surface of the polymer film can be performed, and the surface coverage can be obtained by measuring the coverage area of a fragment derived from the compound having a functional group.

< Polymer having a dielectric loss tangent of 0.005 or less >

The polymer film according to the present invention contains a polymer having a dielectric loss tangent of 0.005 or less.

A dielectric loss tangent of 0.005 or less indicates a small degree of electric energy loss. From the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer, the dielectric loss tangent of the polymer is preferably 0.004 or less, more preferably 0.0035 or less, and particularly preferably 0.003 or less. The lower limit of the dielectric loss tangent of the polymer is not particularly limited, but exceeds 0, for example.

The dielectric loss tangent of the polymer in the present invention is measured by determining or separating the chemical structure of the polymer constituting each layer, and using a sample obtained by pulverizing the measured polymer, the measurement method of dielectric loss tangent is performed as follows.

The dielectric loss tangent in the present invention is measured by the following method.

The measurement of dielectric loss tangent was carried out by a resonance perturbation method at a frequency of 10 GHz. A1 GHz cavity resonator (KANTO Electronic Application and Development Inc. manufactured by "CP 531") was connected to a network analyzer (manufactured by Agilent Technology Co. "E8363B"), and a film sample (width: 2.0 mm. Times. Length: 80 mm) was inserted into the cavity resonator, and dielectric loss tangent was measured from the change in resonance frequency before and after 96 hours of insertion under an environment of a temperature of 25℃and a humidity of 60% RH.

In the case of measuring the dielectric loss tangent of each layer included in the polymer film, unnecessary layers were cut by a razor or the like to prepare a sample for evaluation of only the target layer.

The weight average molecular weight Mw of the polymer having a loss tangent of 0.005 or less is preferably 1,000 or more, more preferably 2,000 or more, and still more preferably 5,000 or more. The weight average molecular weight Mw of the polymer having a dielectric loss tangent of 0.005 or less is preferably 1,000,000 or less, more preferably 300,000 or less, and particularly preferably less than 100,000.

From the viewpoints of the dielectric loss tangent of the polymer film, adhesion to the metal layer, and heat resistance, the melting point Tm or 5 mass% reduction temperature Td of the polymer having a dielectric loss tangent of 0.005 or less is preferably 200 ℃ or more, more preferably 250 ℃ or more, still more preferably 280 ℃ or more, and particularly preferably 300 ℃ or more. The upper limit of Tm or Td is not particularly limited, and Tm or Td is, for example, 500 ℃ or less, preferably 420 ℃ or less.

The melting point Tm in the present invention is measured using a differential scanning calorimetric analysis (DSC) device.

Also, the 5 mass% reduction temperature Td in the present invention is measured by using a thermogravimetric analysis (TGA) apparatus. Specifically, the weight of the sample placed in the measuring tray is set as an initial value, and the temperature at which the temperature rise weight is reduced by 5 mass% from the initial value is set as a5 mass% reduction temperature Td.

From the viewpoints of the dielectric loss tangent of the polymer film, adhesion to a metal layer, and heat resistance, the glass transition temperature Tg of the polymer having a dielectric loss tangent of 0.005 or less is preferably 150 ℃ or higher, more preferably 200 ℃ or higher. The upper limit of Tg is not particularly limited, and Tg is, for example, less than 350 ℃, preferably less than 280 ℃, and more preferably 280 ℃ or less.

The glass transition temperature Tg in the present invention is measured using a Differential Scanning Calorimeter (DSC) device.

In the present invention, the type of the polymer having a dielectric loss tangent of 0.005 or less is not particularly limited, and a known polymer can be used.

Examples of the polymer having a dielectric loss tangent of 0.005 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, polyether ether ketone, polyolefin, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenylene oxide, and modified products thereof, and polyether imide; an elastomer such as a copolymer of glycidyl methacrylate and polyethylene; thermosetting resins such as phenolic resins, epoxy resins, polyimide resins, and cyanate resins.

Among them, the polymer having a dielectric loss tangent of 0.005 or less is preferably at least one polymer selected from the group consisting of a liquid crystal polymer, a fluorine-based polymer, a polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenic unsaturated bond, and polyether ether ketone, more preferably at least one polymer selected from the group consisting of a liquid crystal polymer and a fluorine-based polymer, particularly preferably a liquid crystal polymer from the viewpoint of dielectric loss tangent of the polymer film, and most preferably a fluorine-based polymer from the viewpoint of heat resistance and mechanical strength.

Liquid crystalline polymers

The dielectric loss tangent of the liquid crystal polymer contained in the polymer film of the present invention is preferably 0.01 or less, and from the viewpoint of the dielectric loss tangent of the polymer film, the liquid crystal polymer having a dielectric loss tangent of 0.005 or less is preferable.

In the present invention, the liquid crystal polymer used as the polymer having a dielectric loss tangent of 0.005 or less is not particularly limited as long as the dielectric loss tangent is 0.005 or less, and known liquid crystal polymers can be used.

The liquid crystal polymer may be a thermotropic liquid crystal polymer exhibiting liquid crystal property in a molten state, or may be a lyotropic liquid crystal polymer exhibiting liquid crystal property in a solution state. In the case where the liquid crystal polymer is a thermotropic liquid crystal polymer, the liquid crystal polymer is preferably melted at a temperature of 450 ℃ or less.

Examples of the liquid crystal polymer include liquid crystal polyesters, liquid crystal polyester amides in which an amide bond is introduced into the liquid crystal polyesters, liquid crystal polyester ethers in which an ether bond is introduced into the liquid crystal polyesters, and liquid crystal polyester carbonates in which a carbonate bond is introduced into the liquid crystal polyesters.

Further, from the viewpoints of liquid crystallinity and linear expansion coefficient, the liquid crystal polymer is preferably a polymer having an aromatic ring, and more preferably an aromatic polyester or an aromatic polyester amide.

The liquid crystal polymer may be a polymer in which an isocyanate-derived bond such as an imide bond, a carbodiimide bond, or an isocyanate bond is further introduced into the aromatic polyester or the aromatic polyester amide.

The liquid crystal polymer is preferably a wholly aromatic liquid crystal polymer obtained by using only an aromatic compound as a raw material monomer.

Examples of the liquid crystal polymer include the following liquid crystal polymers.

1) A liquid crystal polymer 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 an aromatic diol, an aromatic hydroxylamine, and an aromatic diamine.

2) A liquid crystal polymer obtained by polycondensing a plurality of aromatic hydroxycarboxylic acids.

3) A liquid crystal polymer obtained by polycondensing (i) an aromatic dicarboxylic acid and (ii) at least one compound selected from the group consisting of an aromatic diol, an aromatic hydroxylamine and an aromatic diamine.

4) A liquid crystal polymer obtained by polycondensing (i) a polyester such as polyethylene terephthalate and (ii) an aromatic hydroxycarboxylic acid.

Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxylamine, and the aromatic diamine may be replaced with polycondensable derivatives, respectively and independently.

For example, the aromatic hydroxycarboxylic acid and the aromatic dicarboxylic acid can be substituted with an aromatic hydroxycarboxylic acid ester and an aromatic dicarboxylic acid ester by converting the carboxyl group to an alkoxycarbonyl group or an aryloxycarbonyl group.

By converting the carboxyl group into a haloformyl group, the aromatic hydroxycarboxylic acid and the aromatic dicarboxylic acid can be substituted with an aromatic hydroxycarboxylic acid halide and an aromatic dicarboxylic acid halide.

By converting the carboxyl group into an acyloxycarbonyl group, the aromatic hydroxycarboxylic acid and the aromatic dicarboxylic acid can be substituted with an aromatic hydroxycarboxylic acid anhydride and an aromatic dicarboxylic acid anhydride.

Examples of the polymerizable derivative of a compound having a hydroxyl group such as an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic hydroxylamine include a derivative (acylate) obtained by acylating a hydroxyl group to convert it into an acyloxy group.

For example, an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic hydroxylamine can be substituted with an acylate by acylating a hydroxyl group to convert it to an acyloxy group.

Examples of the polymerizable derivative of the compound having an amino group such as an aromatic hydroxylamine and an aromatic diamine include a derivative (acylate) obtained by acylating an amino group to convert it into an amido group.

For example, an amino group is acylated to be converted into an amido group, whereby an aromatic hydroxylamine and an aromatic diamine can be substituted into an acylate, respectively.

From the viewpoints of liquid crystallinity, dielectric loss tangent of the polymer film, and adhesion to the metal layer, the liquid crystal polymer preferably has a structural unit represented by any one of the following formulas (1) to (3), more preferably has a structural unit represented by the following formula (1), and particularly preferably has a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3). Hereinafter, the structural unit represented by the formula (1) and the like are also referred to as "unit (1)", and the like.

Formula (1) -O-Ar ¹ -CO-

Formula (2) -CO-Ar ² -CO-

Formula (3) -X-Ar ³ -Y-

Formula (4) -Ar ⁴-Z-Ar⁵ -

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, 2-ethylhexyl, n-octyl and n-decyl. The number of carbon atoms of the alkyl group is preferably 1 to 10.

Examples of the aryl group include phenyl, o-tolyl, m-tolyl, p-tolyl, 1-naphthyl and 2-naphthyl. The number of carbon atoms of the aryl group is preferably 6 to 20.

When the hydrogen atom in Ar ¹～Ar³ is substituted with a halogen atom, an alkyl group or an aryl group, the number of substituents is preferably 2 or less, more preferably 1, independently of each other.

Examples of the alkylene group include methylene, 1-ethanediyl, 1-methyl-1, 1-ethanediyl, 1-butanediyl and 2-ethyl-1, 1-hexanediyl. The number of carbon atoms of the alkylene group is preferably 1 to 10.

The unit (1) is a structural unit derived from an aromatic hydroxycarboxylic acid.

As the unit (1), a mode in which Ar ¹ is p-phenylene (structural unit derived from p-hydroxybenzoic acid), a mode in which Ar ¹ is 2, 6-naphthylene (structural unit derived from 6-hydroxy-2-naphthoic acid), or a mode in which Ar ¹ is 4,4 '-biphenylene (structural unit derived from 4' -hydroxy-4-biphenylcarboxylic acid) is preferable.

The unit (2) is a structural unit derived from an aromatic dicarboxylic acid.

As the unit (2), a mode in which Ar ² is p-phenylene (structural unit derived from terephthalic acid), a mode in which Ar ² is m-phenylene (structural unit derived from isophthalic acid), a mode in which Ar ² is 2, 6-naphthylene (structural unit derived from 2, 6-naphthalenedicarboxylic acid), or a mode in which Ar ² is diphenyl ether-4, 4 '-diyl (structural unit derived from diphenyl ether-4, 4' -dicarboxylic acid) is preferable.

The unit (3) is a structural unit derived from an aromatic diol, an aromatic hydroxylamine or an aromatic diamine.

As the unit (3), a mode in which Ar ³ is p-phenylene (structural unit derived from hydroquinone, p-aminophenol or p-phenylenediamine), a mode in which Ar ³ is m-phenylene (structural unit derived from isophthalic acid), or a mode in which Ar ³ is 4,4 '-biphenylene (structural unit derived from 4,4' -dihydroxybiphenyl, 4-amino-4 '-hydroxybiphenyl or 4,4' -diaminobiphenyl) is preferable.

The content of the unit (1) is preferably 30 mol% or more, more preferably 30 mol% to 80 mol%, further preferably 30 mol% to 60 mol%, particularly preferably 30 mol% to 40 mol%, based on the total amount of all the structural units.

The content of the unit (2) is preferably 35 mol% or less, more preferably 10 mol% to 35 mol%, further preferably 20 mol% to 35 mol%, particularly preferably 30 mol% to 35 mol%, based on the total amount of all the structural units.

The content of the unit (3) is preferably 35 mol% or less, more preferably 10 mol% to 35 mol%, further preferably 20 mol% to 35 mol%, particularly preferably 30 mol% to 35 mol%, based on the total amount of all the structural units.

The more the content of the unit (1), the more easily the heat resistance, strength and rigidity are improved, but if it is too much, the solubility in a solvent is easily lowered.

The total amount of all the structural units is a value obtained by summing up the amounts (mol) of the respective structural units. The mass of each structural unit is calculated by dividing the mass of each structural unit constituting the liquid crystal polymer by the formula weight of each structural unit.

In the case where the ratio of the content of the unit (2) to the content of the unit (3) is represented by [ the content of the unit (2 ]/[ the content of the unit (3) ] (mol/mol), it is preferably 0.9/1 to 1/0.9, more preferably 0.95/1 to I/0.95, still more preferably 0.98/1 to 1/0.98.

The liquid crystal polymer may have two or more types of units (1) to (3) independently. The liquid crystal polymer may have other structural units than the units (1) to (3). The content of the other structural units is preferably 10 mol% or less, more preferably 5 mol% or less, based on the total amount of all the structural units.

Since the liquid crystal polymer has excellent solubility in a solvent, it preferably has a unit (3) in which at least one of X and Y is an imino group, that is, at least one of a structural unit derived from an aromatic hydroxylamine and a structural unit derived from an aromatic diamine, and more preferably has a unit (3) in which only at least one of X and Y is an imino group.

The liquid crystal polymer is preferably produced by melt-polymerizing a raw material monomer corresponding to a structural unit constituting the liquid crystal polymer. Melt polymerization may also be carried out in the presence of a catalyst. Examples of the catalyst 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. The catalyst is preferably a nitrogen-containing heterocyclic compound. If necessary, the melt polymerization may be further solid-phase polymerization.

The flow initiation temperature of the liquid crystal polymer is preferably 180℃or higher, more preferably 200℃or higher, and still more preferably 250℃or higher. The flow initiation temperature is preferably 350℃or lower, more preferably 330℃or lower, and still more preferably 310℃or lower. When the flow initiation temperature of the liquid crystal polymer is within the above range, the solubility, heat resistance, strength and rigidity are excellent, and the viscosity of the solution is suitable.

The Flow start Temperature is also called the Flow Temperature (Flow Temperature) or the Flow Temperature, which is a Temperature at which when a liquid crystal polymer is melted while heating up at a rate of 4 ℃/min under a load of 9.8MPa (100 kg/cm ²) using a capillary thermometer and extruded from a nozzle having an inner diameter of 1mm and a length of 10mm, a viscosity of 4,800 pa·s (48,000 poise) is exhibited, and becomes a reference for the molecular weight of the liquid crystal polyester (xiaozhi monoxiao "liquid crystal polymer-synthesis/molding/application-", CMC co., ltd., 6 month 5 days in 1987, refer to p.95).

The weight average molecular weight of the liquid crystal polymer is preferably 1,000,000 or less, more preferably 3,000 ～ 300,000, still more preferably 5,000 ～ 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 conductivity, heat resistance, strength and rigidity in the thickness direction are excellent in the film after heat treatment.

Fluorine-based polymer

From the viewpoints of heat resistance and mechanical strength, the polymer having a dielectric loss tangent of 0.005 or less is preferably a fluorine-based polymer.

In the present invention, the kind of the fluorine-based polymer used as the polymer having a dielectric loss tangent of 0.005 or less is not particularly limited as long as the dielectric loss tangent is 0.005 or less, and known fluorine-based polymers can be used.

Further, as the fluorine-based polymer, there can be mentioned a fluorinated alpha-olefin monomer, that is, a homopolymer and a copolymer containing a structural unit derived from an alpha-olefin monomer having at least 1 fluorine atom. Further, as the fluorine-based polymer, there is exemplified a copolymer comprising a structural unit derived from a fluorinated alpha-olefin monomer and a structural unit derived from a non-fluorinated ethylenically unsaturated monomer reactive with the fluorinated alpha-olefin monomer.

Examples of the fluorinated alpha-olefin monomer 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、CF₂CH＝CF₂、CF₂CH＝CH₂、CHF₂CH＝CHF、CF₃CF＝CF₂ and perfluoro (alkyl group having 2 to 8 carbon atoms) vinyl ethers (for example, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether and perfluorooctyl vinyl ether). Among them, the fluorinated α -olefin monomer is preferably at least one monomer selected from tetrafluoroethylene (CF ₂＝CF₂), chlorotrifluoroethylene (ccif=cf ₂), (perfluorobutyl) ethylene, vinylidene fluoride (CH ₂＝CF₂) and hexafluoropropylene (CF ₂＝CFCF₃).

Examples of the non-fluorinated ethylenically unsaturated monomer include ethylene, propylene, butene, an ethylenically unsaturated aromatic monomer (for example, styrene and α -methylstyrene), and the like.

The fluorinated alpha-olefin monomer may be used singly or in combination of two or more.

Further, the non-fluorinated ethylenically unsaturated monomer may be used singly or in combination of two or more.

Examples of the fluorine-based polymer include poly (chlorotrifluoroethylene) (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) (e.g., poly (tetrafluoroethylene-perfluoropropyl vinyl ether)), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), poly (vinylidene fluoride-chlorotrifluoroethylene), perfluoropolyether, perfluorosulfonic acid, and perfluoropolyoxetane.

The fluorine-based polymer may have a structural unit derived from ethylene fluoride or propylene fluoride.

The fluorine-based polymer may be used alone or in combination of two or more.

The fluorine-based polymer is preferably FEP, PFA, ETFE or PTFE.

FEP is available under the trade name of teflon (registered trademark) FEP (TEF LON (registered trademark) FEP) from DuPont de Nemours, inc. PFA is available under the trade name of NEOFLON PFA (NEOFLON PFA) from Daikin Industries, ltd, TEFLON (registered trademark) PFA (registered trademark) from DuPont de Nemours, inc, or HYFLON PFA from Solvay Solex is Inc.

The fluorine-based polymer more preferably contains PTFE. The PTFE may also be a PTFE homopolymer, a partially modified PTFE homopolymer, or a combination comprising one or both. A portion of the modified PTFE homopolymer preferably contains less than 1 mass% of structural units derived from a comonomer other than tetrafluoroethylene, based on the total mass of the polymer.

The fluorine-containing polymer may be a crosslinkable fluorine-containing polymer having a crosslinkable group. The crosslinkable fluoropolymer can be crosslinked by a conventionally known crosslinking method. One representative crosslinkable fluoropolymer is a fluoropolymer having (meth) acryloyloxy groups. For example, the crosslinkable fluoropolymer can be represented by the following formula:

H₂C＝CR'COO-(CH₂)_n-R-(CH₂)_n-OOCR'＝CH₂。

Wherein R is an oligomer chain comprising structural units derived from a fluorinated alpha-olefin monomer, R' is H or-CH ₃, and n is 1 to 4.R may be a fluorine-based oligomer chain containing a structural unit derived from tetrafluoroethylene.

Since the radical crosslinking reaction is started through the (meth) acryloyloxy group on the fluorine-based polymer, the fluorine-containing polymer having the (meth) acryloyloxy group is exposed to the radical source, whereby a crosslinked fluorine-containing polymer network structure can be formed. The radical source is not particularly limited, but a photo radical polymerization initiator or an organic peroxide may be preferably used. Preferred photo-radical polymerization initiators and organic peroxides are well known in the art. The crosslinkable fluoropolymer is commercially available, and for example, duPont de Nemours, vitonB produced by inc.

Polymers of compounds having a cycloaliphatic hydrocarbon group and a group having an ethylenically unsaturated bond

The polymer having a dielectric loss tangent of 0.005 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 the polymer of the compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond include thermoplastic resins having a structural unit derived from a cyclic olefin monomer such as norbornene or a polycyclic norbornene-based monomer.

The polymer of the compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond may be a ring-opened polymer of the above cyclic olefin or a hydrogenated product of a ring-opened copolymer using two or more kinds of cyclic olefins, or may be an addition polymer of a cyclic olefin and an aromatic compound having an ethylenically unsaturated bond such as a chain olefin or a vinyl group. Further, a polar group may be introduced into a polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond.

The polymer of the compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond may be used singly or in combination of two or more.

The ring structure of the cyclic aliphatic hydrocarbon group may be a single ring, a condensed ring obtained by condensing 2 or more rings, or a bridged ring.

Examples of the ring structure of the cyclic aliphatic hydrocarbon group include a cyclopentane ring, a cyclohexane ring, a cyclooctane ring, an isophorone ring, a norbornane ring, and a dicyclopentane ring.

The 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.

The number of the cyclic aliphatic hydrocarbon groups in the compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond may be 1 or more, or may be 2 or more.

The polymer of the compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenic unsaturated bond may be a polymer obtained by polymerizing a compound having at least one cyclic aliphatic hydrocarbon group and a group having an ethylenic unsaturated bond, and may be a polymer of a compound having two or more kinds of cyclic aliphatic hydrocarbon groups and a group having an ethylenic unsaturated bond, or may be a copolymer with another ethylenic unsaturated compound having no cyclic aliphatic hydrocarbon group.

Also, the polymer of the compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond is preferably a cycloolefin polymer.

Polyether-ether-ketone (PEEK)

The polymer having a dielectric loss tangent of 0.005 or less may be polyether ether ketone.

Polyether-ether-ketone is one of aromatic polyether-ketone, and the polymer with bond is prepared by sequentially arranging ether bond, ether bond and carbonyl bond (ketone). The bonds are preferably linked by divalent aromatic groups.

In the present invention, the type of polyetheretherketone is not particularly limited as long as the dielectric loss tangent of polyetheretherketone used as the polymer having a dielectric loss tangent of 0.005 or less is 0.005 or less, and known polyetheretherketone can be used.

The polymer having a dielectric loss tangent of 0.005 or less is preferably a polymer soluble in a specific organic solvent (hereinafter, also referred to as "soluble polymer").

Specifically, the soluble polymer in the present invention is a polymer obtained by dissolving 0.1g or more of the soluble polymer in 100g of at least one solvent selected from the group consisting of N-methylpyrrolidone, N-ethylpyrrolidone, methylene chloride, dichloroethane, chloroform, N-methyl-2-pyrrolidone, N-dimethylacetamide, gamma-butyrolactone, dimethylformamide, ethylene glycol monobutyl ether and ethylene glycol monoethyl ether at 25 ℃.

The polymer film may contain only one kind of polymer having a dielectric loss tangent of 0.005 or less, or may contain two or more kinds.

From the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer, the content of the polymer having a dielectric loss tangent of 0.005 or less in the polymer film is preferably 20 to 99% by mass, more preferably 30 to 98% by mass, still more preferably 40 to 97% by mass, and particularly preferably 50 to 95% by mass, relative to the total mass of the polymer film.

< Compound having functional group >

The polymer film according to the present invention contains a compound having a functional group.

In the first and second embodiments, the compound having a functional group in the present invention is a compound other than the polymer having a dielectric loss tangent of 0.005 or less. In the third and fourth embodiments, the compound having a functional group in the present invention is a compound other than the liquid crystal polymer described above.

The compound having a functional group may be any of a low molecular compound, an oligomer, and a polymer, and is preferably an oligomer or a polymer, more preferably a polymer, from the viewpoint of mechanical strength. For example, the polymer film according to the present invention may contain a polymer having a functional group as the compound having a functional group.

In the present invention, the oligomer is a polymer having a weight average molecular weight of less than 2,000, and the polymer has a weight average molecular weight of 2,000 or more.

The functional group is preferably a group that can interact with a metal or a group present on the surface of a metal.

The functional group is preferably at least one group selected from the group consisting of a group capable of covalent bonding, a group capable of ionic bonding, a group capable of hydrogen bonding, and a group capable of dipole interaction.

The compound having a functional group is preferably a low-molecular compound from the viewpoints of the compatibility of the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less with the compound having a functional group and the dielectric loss tangent of the polymer film, and is preferably an oligomer or polymer from the viewpoints of heat resistance, mechanical strength and surface unevenness of the polymer film.

The compound having a functional group preferably interacts with or forms entanglement with a matrix material (for example, a polymer having a dielectric loss tangent of 0.005 or less) contained in the polymer film. As entanglement, there is a method in which a compound having a functional group and a matrix material are mixed at a molecular level to increase a friction coefficient; a means by which the continuous phase of the compound having a functional group and the continuous phase of the matrix material mutually invade; and a manner of forming mechanical bonding (anchoring effect) by the surface shape of each material.

In the case of a mode in which the compound having a functional group and the matrix material intrude into each other, the compound having a functional group is preferably a compound separated from the matrix material or a compound separated from the matrix material by bonding the compound having a functional group to each other.

The number of functional groups of the compound having a functional group may be one or more, or two or more.

The compound having a functional group may have only one functional group or may have two or more functional groups.

Among them, the number of functional groups of the compound having a functional group is preferably 2 or more. The number of functional groups is preferably 10 or less because the electrical characteristics tend to decrease as the number of functional groups increases.

The molecular weight of the low molecular compound used as the compound having a functional group is preferably 50 or more and less than 2,000, more preferably 100 or more and less than 1,000, particularly preferably 200 or more and less than 1,000, from the viewpoint of adhesion to the metal layer.

The weight average molecular weight of the high molecular compound (oligomer, polymer) used as the compound having a functional group is preferably 1,000 or more, more preferably 2,000 or more, further preferably 3,000 or more and 200,000 or less, particularly preferably 5,000 or more and 100,000 or less, from the viewpoints of adhesion to the metal layer and uneven surface distribution.

Further, from the viewpoints of dielectric loss tangent of the polymer film and adhesion to the metal layer, the compound having a functional group is preferably an acrylic resin having a functional group, and more preferably an acrylic copolymer obtained by polymerizing at least a (meth) acrylate compound having a functional group.

The functional group-containing acrylic resin is preferably a perfluoroalkyl group having 4 or more carbon atoms, more preferably a perfluoroalkyl group having 4 to 30 carbon atoms, and particularly preferably a perfluoroalkyl group having 5 to 20 carbon atoms, from the viewpoints of uneven surface distribution and adhesion to a metal layer.

In addition, from the viewpoints of uneven surface distribution and adhesion to the metal layer, the compound having a functional group preferably contains a silicon atom or a fluorine atom, more preferably a silicone resin having a functional group or a fluorine-based resin having a functional group, and particularly preferably a silicone resin having a functional group.

The compound having a functional group may be a compound which is compatible with a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less, or may be an incompatible compound from the viewpoints of dielectric loss tangent of the polymer film and adhesion to the metal layer, but is preferably a compatible compound. Whether or not the compound having a functional group is compatible with a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less can be judged by the difference in SP value.

From the viewpoints of the compatibility of the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less with the compound having a functional group, the dielectric loss tangent of the polymer film and the adhesion to the metal layer, the difference between the Hoy-method-based SP value of the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less and the Hoy-method-based SP value of the compound having a functional group is preferably 5MPa ^0.15 or less. The lower limit of the difference is 0MPa ^0.5. When the difference in SP value is 5MPa ^0.5 or less, the compound having a functional group has a compatible relationship with a polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less.

The compound having a functional group may be a compound that is not compatible with a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less from the viewpoints of surface unevenness and adhesion to a metal layer.

From the viewpoints of surface unevenness and adhesion to a metal layer, the difference between the Hoy-method-based SP value of a polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less and the Hoy-method-based SP value of a compound having a functional group is preferably more than 5MPa ^0.15. The upper limit of the difference is not particularly limited, but is 50MPa ^0.15.

The SP value (solubility parameter value) based on the Hoy method is calculated from the molecular structure by the method described in Polymer Handbook fourth edition. Further, in the case where the resin is a mixture of plural resins, the SP value is calculated for each structural unit.

[ Functional group ]

The functional group in the compound having a functional group is preferably at least one group selected from a group capable of covalent bonding, a group capable of ionic bonding, a group capable of hydrogen bonding, and a group capable of dipole interaction.

The functional group is preferably a group capable of covalent bonding from the viewpoint of adhesion to the metal layer.

Further, from the viewpoints of storage stability and handleability, the functional group is preferably an ion-bondable group, a hydrogen-bondable group, or a dipole-interactable group.

Covalently bondable groups

The covalently-bondable group is not particularly limited as long as it is a group capable of forming a covalent bond, and examples thereof include an epoxy group, an oxetanyl group, an isocyanate group, an acid anhydride group, a carbodiimide group, an N-hydroxy ester group, a glyoxal group, an imide ester group, a haloalkyl group, a thiol group, a hydroxyl group, a carboxyl group, an amino group, an amide group, an aldehyde group, a sulfonic acid group, and the like. Among them, from the viewpoint of adhesion to the metal layer, the covalently-bondable group is preferably at least one functional group selected from the group consisting of an epoxy group, an oxetane group, an isocyanate group, an acid anhydride group, a carbodiimide group, an N-hydroxy ester group, a glyoxal group, an imide ester group, a haloalkyl group, and a thiol group, and particularly preferably an epoxy group.

As will be described later, the metal bonded to the polymer film preferably has a group on the surface that is paired with a functional group of the compound having a functional group.

As a combination of a group capable of covalent bonding and a group paired with the group capable of covalent bonding (a combination of a functional group of a compound having a functional group and a group of a metal contained in a polymer film), specifically, one is an epoxy group and the other is a combination of a hydroxyl group or an amino group.

Further, as a combination of a group capable of covalent bonding and a group paired with a group capable of covalent bonding, for example, a combination of an N-hydroxy ester group or an imide ester group and another amino group can be given.

-Ionizable bond radicals of synthesis-

Examples of the group capable of being ionically bonded include a cationic group and an anionic group.

The cationic group is preferably an onium group. Examples of the onium group include an ammonium group, a pyridinium group, a phosphonium group, an oxonium group, a sulfonium group, an iodonium group, and an iodonium group. Among them, from the viewpoint of adhesion to the metal layer, the group capable of being ionically bonded is preferably an ammonium group, a pyridinium group, a phosphonium group or a sulfonium group, more preferably an ammonium group or a phosphonium group, and particularly preferably an ammonium group.

The anionic group is not particularly limited, and examples thereof include phenolic hydroxyl groups and carboxyl groups 、-SO₃H、-OSO₃H、-PO₃H、-OPO₃H₂、-CONHSO₂-、-SO₂NHSO₂-. Among them, the anionic group is preferably a phosphate group, a phosphonate group, a phosphinate group, a sulfate group, a sulfonate group, a sulfinic acid or a carboxyl group, more preferably a phosphate group or a carboxyl group, and further preferably a carboxyl group.

As a combination of an ion-bondable group and a group paired with the ion-bondable group (a combination of a functional group of a compound having a functional group and a group of a metal contained in a polymer film), specifically, a combination of an acidic group and a basic group is given.

Examples of the acidic group include a carboxyl group, a sulfo group, and a phosphate group, and a carboxyl group is preferable.

In the case where one of the groups is a carboxyl group, examples of the group that can be ionically bonded to the carboxyl group include a tertiary amino group, a pyridyl group, a piperidyl group, and the like.

Hydrogen-bondable groups

Examples of the hydrogen-bonding-capable group include a group having a hydrogen bond donating site and a group having a hydrogen bond accepting site.

The hydrogen bond donating site may have a structure having an active hydrogen atom capable of hydrogen bonding, but is preferably a structure represented by x—h.

X represents a heteroatom, preferably a nitrogen atom or an oxygen atom.

The hydrogen bond donating site is preferably at least one structure selected from the group consisting of a hydroxyl group, a carboxyl group, a primary amide group, a secondary amide group, a primary amino group, a secondary amino group, a primary sulfonamide group, a secondary sulfonamide group, an imide group, a urea bond, and a urethane bond, more preferably at least one structure selected from the group consisting of a hydroxyl group, a carboxyl group, a primary amide group, a secondary amide group, a primary sulfonamide group, a secondary sulfonamide group, a maleimide group, a urea bond, and a urethane bond, still more preferably at least one structure selected from the group consisting of a hydroxyl group, a carboxyl group, a primary amide group, a secondary amide group, a primary sulfonamide group, a secondary sulfonamide group, and a maleimide group, and particularly preferably at least one structure selected from the group consisting of a hydroxyl group and a secondary amide group, from the viewpoint of adhesion to a metal layer.

The hydrogen bond accepting site is preferably a structure including an atom having an unshared electron pair, more preferably a structure including an oxygen atom having an unshared electron pair, still more preferably at least one structure selected from carbonyl groups (including carbonyl structures such as carboxyl groups, amide groups, imide groups, urea bonds, and urethane bonds) and sulfonyl groups (including sulfonyl structures such as sulfonamide groups), and particularly preferably carbonyl groups (including carbonyl structures such as carboxyl groups, amide groups, imide groups, urea bonds, and urethane bonds).

The hydrogen-bonding-capable group is preferably a group having both the hydrogen bond donating site and the hydrogen bond accepting site, preferably a group having a carboxyl group, an amide group, an imide group, a urea bond, a urethane bond or a sulfonamide group, and more preferably a group having a carboxyl group, an amide group, an imide group or a sulfonamide group.

As a combination of a hydrogen-bondable group and a group paired with the hydrogen-bondable group (a combination of a functional group of a compound having a functional group and a group having a surface of a metal), specifically, one is a group having a hydrogen bond donating site, and the other is a combination of groups having a hydrogen bond accepting site.

For example, when one is a carboxyl group, the other is an amide group, a carboxyl group, or the like.

The combination of a hydrogen-bondable group and a group paired with a hydrogen-bondable group includes, for example, a combination of one of the groups being a phenolic hydroxyl group and the other group being a phenolic hydroxyl group.

Dipolar interactions functional groups-

The group capable of dipole interaction may be any group having a polarized structure other than the structure represented by x—h (X represents a heteroatom) in the above-mentioned hydrogen-bondable group, and it is preferable to use a group in which atoms having different electronegativity are bonded to each other.

The combination of atoms having different electronegativity is preferably a combination of at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom and a carbon atom, and more preferably a combination of at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom and a sulfur atom and a carbon atom.

Among them, from the viewpoint of adhesion to the metal layer, a combination of a nitrogen atom and a carbon atom, and a combination of a carbon atom and a nitrogen atom, an oxygen atom, and a sulfur atom are preferable, and specifically, cyano groups, cyanurate groups, and sulfonamide groups are more preferable.

As the combination of the dipole-interactable group and the group paired with the dipole-interactable group (the combination of the functional group of the compound having a functional group and the group having a surface of a metal), a combination of the same dipole-interactable group is preferably given.

Examples of the combination of the dipole-interactable group and the group paired with the dipole-interactable group include a combination of a cyano group and another cyano group.

Further, as a combination of a group capable of dipole interaction and a group paired with a group capable of dipole interaction, for example, one is a sulfonic acid amide group, and the other is a combination of sulfonic acid amide groups.

Specifically, the functional group in the compound having a functional group preferably contains at least one selected from the group consisting of an epoxy group, an oxetanyl group, an isocyanate group, an acid anhydride group, a carbodiimide group, an N-hydroxy ester group, a glyoxal group, an imide ester group, a haloalkyl group, a thiol group, a hydroxyl group, a carboxyl group, an amino group, an amide group, an isocyanate group, an aldehyde group, a sulfonic acid group, an ammonium group, a pyridinium group, a phosphonium group, an oxonium group, a sulfonium group, an iodonium group, a phosphate group, a phosphonate group, a phosphinate group, a sulfate group, a sulfonate group, a sulfinic acid or a carboxyl group, a hydroxyl group, a carboxyl group, a primary amide group, a secondary amide group, a primary amino group, a secondary sulfonamide group, an imide group, a urea bond, and a urethane bond. From the viewpoint of improving adhesion, the functional group in the compound having a functional group is more preferably an epoxy group, an oxetane group, an isocyanate group, an acid anhydride group, a carbodiimide, an N-hydroxy ester group, a glyoxal group, an imide ester group, a haloalkyl group, or a thiol group.

Specific examples of bonding or interaction of two functional groups are shown below, but the bonding or interaction in the present invention is not limited thereto.

[ Chemical formula 3]

The compound having a functional group is preferably a polymer having a functional group, more preferably an acrylic resin having a functional group or a silicone resin having a functional group, from the viewpoints of dielectric loss tangent of the polymer film and adhesion to the metal layer.

Further, from the viewpoints of dielectric loss tangent of the polymer film and adhesion to the metal layer, the compound having a functional group preferably contains a liquid crystal polymer obtained by polymerizing a liquid crystal polymer precursor having a polymerizable group.

The polymer film may contain only one kind of compound having a functional group, or may contain two or more kinds.

From the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer, the content of the compound having a functional group in the polymer film is preferably 0.05 to 50% by mass, more preferably 0.1to 30% by mass, still more preferably 0.2 to 10% by mass, and particularly preferably 0.5 to 5% by mass, relative to the total mass of the polymer film.

< Third component and immobilization >

From the viewpoints of dielectric loss tangent, adhesion to a metal layer, heat resistance, and mechanical strength of the polymer film, the polymer film according to the present invention preferably further comprises a third component obtained by fixing the compound having a functional group to the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less.

The third component is preferably a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less, and is preferably a compound other than the compound having a functional group.

As a method for fixing the compound having a functional group to the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less, for example, a device in which a three-dimensional crosslinked structure is formed in a polymer film and the polymer film is fixed, or a device in which a polymer having a functional group interacting with the compound having a functional group and a polymer compatible with the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less is used and the polymers are entangled with each other and fixed is preferable.

The polymer film according to the present invention preferably has a three-dimensional crosslinked structure from the viewpoints of dielectric loss tangent, adhesion to a metal layer, heat resistance, and mechanical strength of the polymer film.

As a method for forming a three-dimensional crosslinked structure, a method of polymerizing a polyfunctional reactive compound (for example, a polyfunctional monomer) to form a cured product of the polyfunctional reactive compound is exemplified.

That is, from the viewpoints of dielectric loss tangent of the polymer film, adhesion to the metal layer, heat resistance, and mechanical strength, the third component is preferably a cured product containing a polyfunctional reactive compound, and more preferably a cured product containing a polyfunctional (meth) acrylate compound.

The cured product of the polyfunctional reactive compound is a compound in which the reactive group of the polyfunctional reactive compound is substantially rendered unreactive by various curing reactions such as a crosslinking reaction and a polymerization reaction. That is, a part of the reactive groups of the polyfunctional reactive compound may be unreacted, for example, 50% or more of all the reactive groups of the polyfunctional reactive compound may be eliminated. The proportion of the disappearance of the reactive groups of the polyfunctional reactive compound is preferably 80% or more, more preferably 90% or more, and even more preferably 100% (that is, the state in which all the reactive groups of the polyfunctional reactive compound have disappeared). The degree of disappearance of the reactive group can be measured by a known method, for example, a method of determining a cured product of the polyfunctional reactive compound contained in the polymer film, and measuring by infrared absorption spectrum or the like.

The cured product of the polyfunctional reactive compound may be a homopolymer of the polyfunctional reactive compound, may be a copolymer of two or more polyfunctional reactive compounds, or may be a copolymer of one or more polyfunctional reactive compounds and one or more monofunctional reactive compounds (monofunctional monomers).

The cured product of the polyfunctional reactive compound is not particularly limited, and is preferably an addition polymerization resin.

As the polyfunctional reactive compound, a known polyfunctional monomer can be used, and a polyfunctional ethylenically unsaturated compound is preferable.

Examples of the polyfunctional ethylenically unsaturated compound include a polyfunctional (meth) acrylate compound, a polyfunctional (meth) acrylamide compound, a polyfunctional vinyl compound, a polyfunctional styrene compound, and a mixture thereof. Among them, the polyfunctional ethylenically unsaturated compound is preferably a polyfunctional (meth) acrylate compound.

In order to adjust the mesh size of the three-dimensional crosslinked structure, the cured product of the polyfunctional reactive compound may be copolymerized with a monofunctional reactive compound.

In addition, a polymerization initiator is preferably used for forming a cured product of the polyfunctional reactive compound. As the polymerization initiator, a known photopolymerization initiator, a known thermal polymerization initiator, or the like can be used. Among them, the polymerization initiator is preferably a photopolymerization initiator.

Further, the polymer film according to the present invention preferably contains a liquid crystal polymer precursor as a polyfunctional reactive compound from the viewpoints of dielectric loss tangent, adhesion to a metal layer, heat resistance and mechanical strength of the polymer film.

In addition, the liquid crystal polymer precursor is not particularly limited as long as it is a polymerizable liquid crystal polymer. The liquid crystal polymer precursor may be a liquid crystal polymer precursor having a polymerizable group generated by a predetermined treatment (for example, annealing treatment, surface treatment such as plasma treatment) at the time of producing a polymer film, or may have a polymerizable group itself.

In the polymer film according to the present invention, from the viewpoints of dielectric loss tangent, adhesion to a metal layer, heat resistance, and mechanical strength of the polymer film, the third component preferably contains a compound having a functional group which interacts with the compound having a functional group and which is compatible with the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less, more preferably contains a polymer or liquid crystal polymer having a functional group which interacts with the compound having a functional group and which is compatible with the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less, and particularly preferably contains a liquid crystal polymer having a functional group which interacts with the compound having a functional group and which is compatible with the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less.

The preferable mode of the functional group of the compound having a functional group which interacts with the compound having a functional group and which is compatible with the polymer or the liquid crystal polymer having a dielectric tangent of 0.005 or less is the same as the functional group of the compound having a functional group except for the functional group paired with the functional group of the compound having a functional group. For example, in the case where the functional group in the above-mentioned compound having a functional group is an epoxy group, the functional group in the third component may preferably be an amino group, a hydroxyl group, or the like.

From the viewpoints of compatibility, dielectric loss tangent of the polymer film and adhesion to the metal layer, the difference between the Hoy-method-based SP value of the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less and the Hoy-method-based SP value of the compound having a functional group interacting with the compound having a functional group, and the difference between the Hoy-method-based SP value of the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less is preferably 5MPa ^0.15 or less. The lower limit of the difference is 0MPa ^0.15.

The measurement method of the SP value based on the Hoy method is as described above.

Whether or not the third component is compatible with a polymer having a dielectric loss tangent of 0.005 or less can be judged by the difference in SP value. When the difference between SP values is 5MPa ^0.5 or less, the third component is compatible with the polymer having a dielectric loss tangent of 0.005 or less.

The polymer film may contain only one kind of the third component, or may contain two or more kinds.

From the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer, the content of the third component in the polymer film is preferably 1 to 80% by mass, more preferably 2 to 70% by mass, still more preferably 3 to 60% by mass, and particularly preferably 5 to 55% by mass, relative to the total mass of the polymer film.

< Filler >

The polymer film preferably contains a filler from the viewpoints of the linear expansion coefficient and the adhesion to a metal foil or a metal wiring.

The filler may be in the form of particles, may be fibrous, and may be an inorganic filler or an organic filler.

In the polymer film according to the present invention, the number density of the filler in the polymer film is preferably higher than the number density of the filler on the surface of the polymer film from the viewpoints of the linear expansion coefficient and adhesion to a metal foil or a metal wiring.

The number density of the filler was measured by the following method.

The film was cut by a microtome to prepare a cross-sectional sample. The cross-section sample was observed with a scanning electron microscope (about 100-300 times). The number of fillers per 1mm ² was determined as an average value by observing 3 or more so that the total observation area becomes 0.5mm ² or more.

As the inorganic filler, a known inorganic filler can be used.

Examples of the material of the inorganic filler include BN, al ₂O₃、AlN、TiO₂、SiO₂, barium titanate, strontium titanate, aluminum hydroxide, and calcium carbonate, and two or more of these materials.

Among them, the inorganic filler is preferably metal oxide particles or fibers, more preferably silica particles, titania particles or glass fibers, and particularly preferably silica particles or glass fibers, from the viewpoint of adhesion to the metal layer.

The average particle size of the inorganic filler is preferably about 20% to about 40% of the thickness of layer a, for example, 25%, 30% or 35% of the thickness of layer a may also be selected. In the case where the particles or fibers are flat, the length in the short-side direction is indicated.

The average particle diameter of the inorganic filler is preferably 5nm to 20. Mu.m, more preferably 10nm to 10. Mu.m, still more preferably 20nm to 1. Mu.m, particularly preferably 25nm to 500nm, from the viewpoint of adhesion to the metal layer.

As the organic filler, a known organic filler can be used.

Examples of the material of the organic filler include polyethylene, polystyrene, urea resin, polyester, cellulose, acrylic resin, fluorine resin, cured epoxy resin, cross-linked benzoguanamine resin, cross-linked acrylic resin, liquid crystal polymer, and materials containing two or more of them.

The organic filler may be fibrous, such as nanofibers, or may be hollow resin particles.

Among them, the organic filler is preferably a fluororesin particle, a polyester resin particle, a polyethylene particle, a liquid crystal polymer particle, or a nanofiber of a cellulose resin, more preferably a polytetrafluoroethylene particle, a polyethylene particle, or a liquid crystal polymer particle, from the viewpoints of the thermal expansion coefficient and the adhesion to the metal layer.

The liquid crystal polymer particles can be produced, for example, by polymerizing a liquid crystal polymer and pulverizing the polymer into powder by a pulverizer or the like. The average particle diameter of the liquid crystal polymer particles is preferably smaller than the thickness of each layer.

The average particle diameter of the organic filler is preferably 5nm to 20. Mu.m, more preferably 10nm to 1. Mu.m, still more preferably 20nm to 500nm, particularly preferably 25nm to 90nm, from the viewpoints of the thermal expansion coefficient and adhesion to the metal layer.

The polymer film may contain only one kind of filler, or may contain two or more kinds.

From the viewpoint of adhesion to the metal layer, the content of the filler in the polymer film is preferably 5 to 80% by volume, more preferably 10 to 70% by volume, still more preferably 15 to 70% by volume, and particularly preferably 20 to 60% by volume, relative to the total volume of the polymer film.

Other additives-

The polymer film may also contain other additives in addition to the above components.

As the other additive, a known additive can be used. Specifically, for example, leveling agents, antifoaming agents, antioxidants, ultraviolet absorbers, flame retardants, colorants, and the like can be cited.

The polymer film may contain, as other additives, a polymer having a dielectric loss tangent of 0.005 or less or a liquid crystal polymer, and other resins than the compound having a functional group.

Examples of the other resins include thermoplastic resins such as polypropylene, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenylene ether and modified products thereof, and polyether imide; an elastomer such as a copolymer of glycidyl methacrylate and polyethylene; thermosetting resins such as phenol resins, epoxy resins, polyimide resins, and cyanate resins.

The total content of the 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 100 parts by mass of the polymer having a dielectric loss tangent of 0.005 or less.

And, the total content of other additives in the polymer film is preferably less than the content of the compound having a functional group.

The polymer film according to the present invention may have a multilayer structure.

The polymer film according to the present invention preferably has a layer a and a layer B on at least one surface of the layer a, and the layer B contains the compound having a functional group.

The polymer film according to the present invention preferably has a layer a containing a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less and a layer B containing a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group on at least one surface of the layer a, and more preferably has a layer a containing a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less and a layer B containing a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less, a compound having a functional group and a third component on at least one surface of the layer a, from the viewpoints of the dielectric loss tangent of the polymer film and the adhesion to a metal layer.

The layer a may contain only a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less, or may contain a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group.

Also, layer a may also contain a third component, but preferably does not.

In addition, layer a preferably also contains a filler.

The layer B preferably contains a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group, and more preferably contains a polymer or a liquid crystal polymer having a dielectric loss tangent of 0.005 or less, a compound having a functional group, and a third component for fixing the compound having a functional group to the polymer having a dielectric loss tangent of 0.005 or less.

Further, from the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer, the content of the third component in the layer B is preferably more than the content of the third component in the layer a.

The polymer film according to the present invention preferably has a layer C in addition to the layers a and B, and preferably has the layers B, a and C in this order.

In the case where a metal layer is present unlike the above layers, the layer C is preferably a surface layer (outermost layer), and more preferably a surface layer on the side to which metal is attached.

In the case where the film according to the present invention is used as a laminate having a metal layer (for example, a metal foil or a metal wiring), the layer C is preferably arranged between the metal layer and the layer a.

Layer C preferably contains a polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less and a compound having a functional group; more preferably, the liquid crystal composition comprises a polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less, a compound having a functional group, and a third component for fixing the compound having a functional group to the polymer or liquid crystal polymer having a dielectric loss tangent of 0.005 or less.

Further, from the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer, the content of the third component in the layer C is preferably more than the content of the third component in the layer a.

The average thickness of the layer a is not particularly limited, but is preferably 5 μm to 90 μm, more preferably 10 μm to 70 μm, from the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer. Particularly preferably 15 μm to 50. Mu.m.

The method for measuring the average thickness of each layer in the polymer film according to the present invention is as follows.

The polymer film was cut with a microtome, and the cross section was observed with an optical microscope to evaluate the thickness of each layer. The cross section samples were cut at 3 or more, the thickness at 3 or more points was measured in each cross section, and the average value thereof was set as the average thickness.

From the viewpoints of the dielectric loss tangent of the polymer film and adhesion to the metal layer, the average thickness of each of the layers B and C is preferably smaller than that of the layer a.

From the viewpoints of the dielectric loss tangent of the polymer film and the adhesion to the metal layer, the value of the ratio T ^A/T^B of the average thickness T ^A of the layer a to the average thickness T ^B of the layer B is preferably greater than 1, more preferably 2 to 100, still more preferably 2.5 to 20, and particularly preferably 3 to 10.

From the viewpoints of the dielectric loss tangent of the polymer film and the adhesion to the metal layer, the value of the ratio T ^A/T^C of the average thickness T ^A of the layer a to the average thickness T ^C of the layer C is preferably greater than 1, more preferably 2 to 100, still more preferably 2.5 to 20, and particularly preferably 3 to 10.

Further, from the viewpoints of the linear expansion coefficient and the adhesion to a metal foil or a metal wiring, the value of T ^C/T^B, which is the ratio of the average thickness T ^C of the layer C to the average thickness T ^B of the layer B, is preferably 0.2 to 5, more preferably 0.5 to 2, and particularly preferably 0.8 to 1.2.

The average thickness of each of the layers B and 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, independently from the viewpoint of the dielectric loss tangent of the polymer film and the adhesion to the metal layer.

The average thickness of the polymer film according to the present invention is preferably 6 μm to 200 μm, more preferably 12 μm to 100 μm, and particularly preferably 20 μm to 60 μm from the viewpoints of strength, dielectric loss tangent of the polymer film, and adhesion to a metal layer.

The average thickness of the polymer film was measured at 5 arbitrary positions using a bonded film thickness gauge. As the film thickness meter, for example, measurement is performed using an electronic micrometer (manufactured by product names "KG3001A", ANRITSU CORPORATION) as an average value thereof.

From the viewpoint of the dielectric constant, the dielectric loss tangent of the polymer film according to the present invention is preferably 0.020 or less, more preferably 0.010 or less, further preferably 0.005 or less, and particularly preferably more than 0 and 0.003 or less. The dielectric loss tangent can be measured by the same method as the above-mentioned dielectric loss tangent.

The linear expansion coefficient of the polymer film according to the present invention is preferably-20 ppm/K to 50ppm/K, more preferably 10ppm/K to 40ppm/K, still more preferably Oppm/K to 35ppm/K, particularly preferably 10ppm/K to 30ppm/K.

The linear expansion coefficient in the present invention is measured by the following method.

A tensile load of 1g was applied to both ends of a polymer film or each layer having a width of 5mm and a length of 20mm using a thermal mechanical analysis apparatus (TMA), and the temperature was raised to 25℃to 200℃at a rate of 5℃per minute. Then, the temperature was cooled to 30℃at a rate of 20℃per minute, and the temperature was increased at a rate of 5℃per minute, and the linear expansion coefficient was calculated from the slope of the TMA curve at this time between 30℃and 150 ℃.

In the case of measuring each layer, a measurement sample may be produced by shaving off the measured layer by a razor or the like.

Further, in the case where it is difficult to measure the linear expansion coefficient by the above-described method, the measurement is performed by the following method.

The cut sample was prepared by cutting the film with a microtome, and an optical microscope equipped with a heating stage system (HS 82, manufactured by Mettler-Toledo International inc. Was mounted. Then, the temperature is raised to 25 to 200 ℃ at a rate of 5 ℃ per minute. Then, when the temperature is cooled to 30℃at a rate of 20℃per minute and the temperature is raised again at a rate of 5℃per minute, the thickness (ts 30) of the polymer film or each layer at 30℃and the thickness (ts 150) of the polymer film or each layer at 150℃are evaluated, and the value ((ts 150-ts 30)/(150-30)) obtained by dividing the dimensional change by the temperature change is calculated as the linear expansion coefficient of the polymer film or each layer.

< Method for producing Polymer film >

[ Film formation ]

The method for producing the polymer film according to the present invention is not particularly limited, and a known method can be referred to.

The method for producing the polymer film according to the present invention is preferably, for example, a casting method, a coating method, an extrusion method, or the like, and among these, a casting method is particularly preferred. In the case where the polymer film according to the present invention has a multilayer structure, for example, a co-casting method, a multilayer coating method, a co-extrusion method, or the like is preferable. Among them, the coextrusion method is particularly preferable in the case of thin films, and the coextrusion method is particularly preferable in the case of thick films.

In the case of producing a multilayer structure in a polymer film by a co-casting method and a multilayer coating method, it is preferable to use a co-casting method or a multilayer coating method in which components of each layer such as a liquid crystal polymer are dissolved or dispersed in a solvent, respectively, to use a composition for forming layer a, a composition for forming layer B, a composition for forming layer C, and the like.

Examples of the solvent include halogenated hydrocarbons such as methylene chloride, chloroform, 1-dichloroethane, 1, 2-dichloroethane, 1, 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; carbonates such as ethylene carbonate and propylene carbonate; amines such as triethylamine; nitrogen-containing heterocyclic aromatic compounds such as pyridine; nitriles such as acetonitrile and succinonitrile; urea compounds such as N, N-dimethylformamide, N-dimethylacetamide, amide such as N-methylpyrrolidone, and tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethyl sulfoxide and sulfolane; phosphorus compounds such as hexamethylphosphoric acid amide and tri-n-butyl phosphoric acid, etc., and two or more of these compounds can be used.

From the viewpoints of low corrosiveness and easy handling, the solvent is preferably an aprotic compound, particularly an aprotic compound containing no halogen atom. The proportion of the aprotic compound in the whole solvent is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and particularly preferably 90 to 100% by mass. The aprotic compound is preferably an amide such as N, N-dimethylformamide, N-dimethylacetamide, tetramethylurea or N-methylpyrrolidone, or an ester such as γ -butyrolactone, more preferably N, N-dimethylformamide, N-dimethylacetamide or N-methylpyrrolidone, from the viewpoint of easy dissolution of the liquid crystal polymer.

Further, from the viewpoint of the ease of dissolving the liquid crystal polymer, the solvent preferably contains a compound having a dipole moment of 3 to 5. The proportion of the compound having a dipole moment of 3 to 5 in the entire solvent is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and particularly preferably 90 to 100% by mass.

As the aprotic compound, a compound having a dipole moment of 3 to 5 is preferably used.

Further, from the viewpoint of easy removal, the solvent preferably contains a compound having a boiling point of 220 ℃ or less at 1 atmosphere pressure. The proportion of the compound having a boiling point of 220 ℃ or lower at 1 atmosphere pressure in the whole solvent is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and particularly preferably 90 to 100% by mass.

As the aprotic compound, a compound having a boiling point of 220℃or less at 1 atmosphere is preferably used.

The method for producing a polymer film according to the present invention may use a support when produced by the casting method, co-casting method, coating method, multilayer coating method, extrusion method, co-extrusion method, or the like. In the case where a metal layer (metal foil) or the like used in a laminate to be described later is used as a support, the support may be used as it is without being peeled off.

Examples of the support include a metal roll, a metal belt, a glass plate, a resin film, and a metal foil. Among them, the support is preferably a metal roll, a metal belt or a resin film.

Examples of the resin film include Polyimide (PI) films. Examples of commercial products of the resin film include Upiex S and Upiex R manufactured by UBE Corporation, DU PONT-TORAY CO, kapton manufactured by LTD. And SKC Kolon PI manufactured by Inc. IF30, IF70 and LV300.

The support may have a surface treatment layer formed on the surface so as to be easily peeled off. As the surface treatment layer, hard chrome plating, fluororesin, or the like can be used.

The average thickness of the support is not particularly limited, but is preferably 25 μm or more and 75 μm or less, more preferably 50 μm or more and 75 μm or less.

Further, as a method for removing at least a part of the solvent from the cast or coated film-like composition (cast film or coating film), a known drying method can be used without particular limitation.

[ Stretching ]

The polymer film according to the present invention can be stretched in a proper combination from the viewpoints of controlling the molecular orientation and adjusting the linear expansion coefficient and mechanical properties. The stretching method is not particularly limited, and may be performed in a state of containing a solvent or in a state of a dry film, referring to a known method. Stretching in the solvent-containing state may be performed by stretching the film by holding the film, or may be performed by self-shrinkage by drying without stretching the film. Stretching is particularly effective for the purpose of improving elongation at break and strength at break when film brittleness is reduced by adding an inorganic filler or the like.

The method for producing a polymer film according to the present invention may include a step of polymerizing by light or heat, if necessary.

The light irradiation device and the heat application device are not particularly limited, and a known light irradiation device such as a metal halide lamp and a known heat application device such as a heater can be used.

The light irradiation conditions and the heat application conditions are not particularly limited, and may be performed at a desired temperature and time and in a known atmosphere.

[ Heat treatment ]

The method for producing a polymer film according to the present invention preferably includes a step of heat treating (annealing) the film after film formation.

The heat treatment temperature in the step of performing the heat treatment is, in particular, preferably 260 to 370 ℃, more preferably 280 to 360 ℃, and even more preferably 300 to 350 ℃ from the viewpoint of dielectric loss tangent and peel strength. The heat treatment time is preferably 15 minutes to 10 hours, more preferably 30 minutes to 5 hours.

The method for producing a polymer film according to the present invention may include other known steps as needed.

< Use >

The polymer film according to the present invention can be used for various applications, and among them, it can be preferably used for a film for electronic components such as a printed wiring board, and it can be more preferably used for a flexible printed circuit board.

The polymer film according to the present invention can be preferably used as a polymer film for metal adhesion.

(Laminate)

The laminate according to the present invention may be a laminate formed by laminating the polymer films according to the present invention, and preferably has the polymer film according to the present invention and a metal layer having a higher concentration of the compound having a functional group than the inside surface disposed in the polymer film, more preferably has the polymer film according to the present invention and a metal layer disposed on both surfaces of the polymer film, and particularly preferably has a metal layer having both surfaces having a higher concentration of the compound having a functional group than the inside surface disposed in the polymer film.

The metal layer may be a known metal layer, but is preferably a copper layer, for example. That is, the laminate according to the present invention preferably has the polymer film according to the present invention, and the metal layer in the polymer film, in which the concentration of the compound having a functional group is higher than that in the interior, and more preferably has the polymer film according to the present invention, and the metal layers respectively disposed on both surfaces of the polymer film.

In view of adhesion to a metal layer, the polymer film according to the present invention preferably has a layer a and a layer B on at least one surface of the layer a, the metal layer (preferably a copper layer) is disposed on the layer B, and the thickness of the layer B is thicker than the thickness of the metal layer (preferably a copper layer) disposed on the layer B.

The metal layer disposed on the surface of the layer B is preferably a metal layer disposed on the surface of the layer B.

The laminate according to the present invention preferably includes the polymer film according to the present invention having a layer B, a layer a, and a layer C in this order, a metal layer disposed on a surface of the polymer film on the layer B side, and a metal layer disposed on a surface of the polymer film on the layer C side, and more preferably, the metal layers are all copper layers.

The metal layer disposed on the surface of the layer C is preferably a metal layer disposed on the surface of the layer C, more preferably a metal layer disposed on the surface of the layer B is a metal layer disposed on the surface of the layer B, and a metal layer disposed on the surface of the layer C is a metal layer disposed on the surface of the layer C.

The metal layer disposed on the surface of the layer B side and the metal layer disposed on the surface of the layer C side may be made of the same material, thickness, and shape, or may be made of different materials, thicknesses, and shapes. The metal layer disposed on the surface of the layer B side and the metal layer disposed on the surface of the layer C side are preferably metal layers of different materials from each other in terms of adjusting the characteristic impedance.

In addition, from the viewpoint of characteristic impedance adjustment, in the layer B or the layer C, a metal layer may be laminated on the metal layer side where the concentration of the compound having a functional group disposed in the polymer film is higher than that of the inner surface, and another polymer film (preferably another liquid crystal polymer film) may be laminated on the other side.

The surface roughness Rz of the metal layer on the side contacting the polymer film is preferably 1 μm to 10 μm, more preferably 1 μm to 5 μm, particularly preferably 1.5 μm to 3 μm in the case where layer C is not provided, and is preferably less than 1 μm, more preferably 0.5 μm or less, particularly preferably 0.3 μm or less from the viewpoint of reduction in transmission loss of high-frequency signals in the case where layer C is provided.

The lower limit is not particularly limited, but is, for example, 0 μm, since the smaller the surface roughness Rz of the metal layer is, the more preferable.

In the present invention, "surface roughness Rz" means a value obtained by expressing the sum of the maximum value of the height of the peak and the maximum value of the depth of the valley observed by the roughness curve in micrometers in the standard length.

In the present invention, the surface roughness Rz of a metal layer (e.g., copper layer) is measured by the following method.

A roughness curve in the surface of the object (metal layer) to be measured and an average line of the roughness curve were prepared by measuring a square having a longitudinal direction 465.48 μm and a transverse direction 620.64 μm using a noncontact surface/layer cross-sectional shape measuring system VertScan (MITSUBISHI CHEMICALSYSTEMS, inc.). A portion corresponding to the standard length is extracted from the roughness curve. The surface roughness Rz of the object to be measured is measured by obtaining the sum of the maximum value of the height of the peak (i.e., the height from the average line to the peak) and the maximum value of the depth of the valley (i.e., the height from the average line to the valley bottom) observed from the extracted roughness curve.

The method for attaching the polymer film and the metal layer according to the present invention is not particularly limited, and a known lamination method can be used.

The peel strength of the polymer film to the copper layer is preferably 0.5kN/m or more, more preferably 0.7kN/m or more, still more preferably 0.7kN/m to 2.0kN/m, and particularly preferably 0.9kN/m to 1.5kN/m.

In the present invention, the peel strength of the polymer film from the metal layer (e.g., copper layer) is measured by the following method.

A test piece for peeling having a width of 1.0 cm was prepared from a laminate of a polymer film and a metal layer, and the polymer film was fixed on a flat plate with a double-sided tape, and the strength (kN/m) at which the metal layer was peeled from the polymer film at a speed of 50 mm/min was measured by a 180℃method according to JIS C5016 (1994).

The metal layer is 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 bending resistance.

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 copper foil with carrier formed on a support (carrier) in a peelable manner. As the carrier, a known carrier can be used. The average thickness of the support is not particularly limited, but is preferably 10 μm to 100 μm, more preferably 18 μm to 50 μm.

In view of further exhibiting the effects of the present invention, the metal layer preferably has a group capable of interacting with the polymer film on a surface on a side contacting the polymer film. The interactive group is preferably a group corresponding to a functional group of a compound having a functional group contained in the polymer film, for example, an amino group, an epoxy group, and a hydroxyl group, an epoxy group.

Examples of the group capable of interacting with each other include a group as a functional group in the compound having a functional group.

Among them, the group capable of interacting is preferably a group capable of covalent bonding, more preferably an amino group or a hydroxyl group, and particularly preferably an amino group, from the viewpoints of adhesion and ease of handling.

The metal layer in the laminate according to the present invention may be a metal layer having a circuit pattern.

The metal layer in the laminate according to the present invention is preferably processed into a desired circuit pattern, for example, by etching, and is preferably used as a flexible printed circuit board. The etching method is not particularly limited, and a known etching method can be used.

Examples

The present invention will be described more specifically with reference to examples. The materials, amounts used, ratios, processing contents, processing order, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Accordingly, the scope of the present invention is not limited to the specific examples shown below.

Measurement method

[ Dielectric loss tangent ]

The measurement of dielectric loss tangent was carried out by a resonance perturbation method at a frequency of 10 GHz. A10 GHz cavity resonator (KANTO Electronic Application and Development Inc. manufactured by "CP 531") was connected to a network analyzer (manufactured by Agilent Technology Co., ltd. "E8363B"), a sample (width: 2.0 mm. Times. Length: 80 mm) of the polymer film or each layer was inserted into the cavity resonator, and the dielectric loss tangent of the polymer film or each layer was measured from the change in resonance frequency before and after insertion for 96 hours under an environment of a temperature of 25℃and a humidity of 60% RH.

[ Surface coating Rate ]

A polymer film containing no compound having a functional group and a compound having a functional group are prepared. The surface energy of the polymer film containing no compound having a functional group and the compound having a functional group was calculated. In the same manner, the surface energy is calculated for the polymer film as the measurement object.

Specifically, after the humidity was adjusted at 25 ℃ for 24 hours at a relative humidity of 60%, the contact angle with water and the contact angle with diiodomethane were measured, and the surface energy was calculated from the measured contact angles by the method of Owens.

A calibration curve was prepared using the surface energy of the polymer film containing no compound having a functional group and the surface energy of the compound having a functional group.

[ Peel Strength ]

A test piece for peeling was prepared with a width of 1.0 cm from a laminate of a polymer film and a copper layer, the polymer film was fixed on a flat plate with a double-sided tape, and the strength (kN/m) at which the polymer film was peeled from the copper layer at a speed of 50 mm/min from the laminate was measured by a 180℃method according to JIS C5016 (1994).

Production example

< Polymer having a dielectric loss tangent of 0.005 or less >

LC-A: liquid crystalline polymer produced by the following production method

LC-A production

To a reactor equipped with a stirrer, a torque meter, a nitrogen inlet tube, a thermometer and a reflux condenser, 940.9g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 377.9g (2.5 mol) of 4-hydroxy-acetaminophen, 415.3g (2.5 mol) of isophthalic acid and 867.8g (8.4 mol) of acetic anhydride were added, and after the gas in the reactor was replaced with nitrogen, the temperature was raised from room temperature (23 ℃) to 140℃over 60 minutes while stirring under a nitrogen stream, and refluxed at 140℃for 3 hours.

Then, while distilling the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150℃to 300℃over 5 hours, and after holding at 300℃for 30 minutes, the content was taken out of the reactor and cooled to room temperature. The obtained solid matter was pulverized with a pulverizer to obtain a powdery liquid crystal polyester (B1). The flow initiation temperature of the liquid-crystalline polyester (B1) was 193.3 ℃.

The liquid-crystalline polyester (B1) obtained above was heated from room temperature to 160 ℃ over 2 hours and 20 minutes under a nitrogen atmosphere, then heated from 160 ℃ to 180 ℃ over 3 hours and 20 minutes, and kept at 180 ℃ for 5 hours, thereby solid-phase polymerizing, then cooled, and then pulverized with a pulverizer, thereby obtaining a powdery liquid-crystalline polyester (B2). The flow initiation temperature of the liquid-crystalline polyester (B2) was 220 ℃.

The liquid crystalline polyester (B2) obtained above was heated from room temperature (23 ℃) to 180℃over 1 hour and 25 minutes under A nitrogen atmosphere, then heated from 180℃to 255℃over 6 hours and 40 minutes, and kept at 255℃for 5 hours, thereby solid-phase polymerizing, followed by cooling, to obtain A powdery liquid crystalline polyester (LC-A). The flow onset temperature of LC-A was 302 ℃. The melting point of this LC-A was measured using A differential scanning calorimeter and found to be 311 ℃.

LC-B: liquid crystalline polymer produced by the following production method

LC-B production

To a reactor equipped with a stirrer, a torque meter, a nitrogen inlet tube, a thermometer and a reflux condenser, 940.9g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 377.9g (2.5 mol) of 4-hydroxy-acetaminophen, 415.3g (2.5 mol) of isophthalic acid and 867.8g (8.4 mol) of acetic anhydride were added, and after the gas in the reactor was replaced with nitrogen, the temperature was raised from room temperature (23 ℃) to 143℃over 60 minutes while stirring under a nitrogen stream, and refluxed at 143℃for 1 hour.

Then, while distilling the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150℃to 300℃over 5 hours, and after holding at 300℃for 30 minutes, the content was taken out of the reactor and cooled to room temperature. The obtained solid matter was pulverized with a pulverizer to obtain a powdery liquid crystal polyester (B1).

The liquid-crystalline polyester (B1) obtained above was heated from room temperature to 160 ℃ over 2 hours and 20 minutes under a nitrogen atmosphere, then heated from 160 ℃ to 180 ℃ over 3 hours and 20 minutes, and kept at 180 ℃ for 5 hours, thereby solid-phase polymerizing, then cooled, and then pulverized with a pulverizer, thereby obtaining a powdery liquid-crystalline polyester (B2).

The liquid crystalline polyester (B2) obtained above was heated from room temperature (23 ℃) to 180℃over 1 hour and 20 minutes under a nitrogen atmosphere, then heated from 180℃to 240℃over 5 hours and held at 240℃for 5 hours, thereby solid-phase polymerizing it, and then cooled to obtain a powdery liquid crystalline polyester (LC-B).

LC-C: liquid crystalline polymer produced by the following production method

LC-C production

To a reactor equipped with a stirrer, a torque meter, a nitrogen inlet tube, a thermometer and a reflux condenser, 941g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 273g (2.5 mol) of 4-aminophenol, 415g (2.5 mol) of isophthalic acid and 1123g (11 mol) of acetic anhydride were added, and after the gas in the reactor was replaced with nitrogen, the temperature was raised from room temperature (23 ℃) to 150℃over 15 minutes while stirring under a nitrogen stream, and refluxed at 150℃for 3 hours.

Then, while distilling the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150℃to 320℃over 3 hours, and after maintaining until the viscosity was confirmed to be increased, the content was taken out of the reactor and cooled to room temperature. The obtained solid matter was pulverized with a pulverizer to obtain a powdery liquid crystal polyester (C1).

The liquid-crystalline polyester (C1) obtained above was solid-phase polymerized by holding it at 250℃for 3 hours under a nitrogen atmosphere, then cooled, and then pulverized by a pulverizer to obtain a powdery liquid-crystalline polyester (LC-C).

< Polyphenylene ether >

P-1: a mixture of commercially available particles of polyphenylene ether (SA 120, manufactured by SABIC Co., ltd., weight average molecular weight Mw2, 600)/bisphenol A type epoxy resin (EPICLON S manufactured by DIC Corporation, average epoxy group number 2)/bisphenol A type cyanate resin (Badey, manufactured by Lonza K.K.; manufactured by LTD.)/aromatic condensed phosphoric acid ester (PX-200,DAIHACHI CHEMICAL INDUSTRY CO.; manufactured by LTD.)/aluminum triethylphosphonate (EXOLIT OP-935, manufactured by Clariant (Japan) K.K.; zinc octoate= 25/34/25/8/8/0.01 (mass ratio))

< Compound having functional group >

The mass ratio shown in Table 1 was obtained by using any one of the following polymers A-1 to A-5.

[ Production of Polymer A-1 ]

Synthesis of monomer 1

5.0G of 1, 1-dimethoxycyclohexane, 9.0g of 2-hydroxymethacrylate, 25.0g of 1H, 2H-perfluorooctanol, 0.87g of pyridine p-toluenesulfonate and 30mL of toluene were weighed into a 100mL eggplant-shaped flask, stirred at 40℃for 1 hour, and then stirred at 40℃for 4 hours under reduced pressure of 100 mmHg. After the obtained reaction solution was cooled to room temperature (23 ℃) and washed with saturated aqueous sodium hydrogencarbonate, the obtained organic layer was dried over anhydrous magnesium sulfate, concentrated, and subjected to silica gel column chromatography, whereby 8.0g of monomer 1 represented by the following formula was obtained as a colorless liquid (yield 40%).

[ Chemical formula 4]

Synthesis of monomer 2

To a 2,000 mL three-necked flask equipped with a stirring blade, a thermometer and a dropping funnel, 100g of 2-hydroxyethyl methacrylate and 240mL of N, N-dimethylacetamide (DMAc) were added, and the mixture was cooled by an ice bath. Then, 126.8g of 3-chloropropionyl chloride was added dropwise thereto, and the mixture was stirred under ice-cooling for 3 hours. After the obtained reaction solution was cooled to room temperature, 1,000 mL of ethyl acetate was subjected to liquid separation washing with 1mol/L hydrochloric acid, a saturated aqueous sodium hydrogencarbonate solution and water, and the obtained organic layer was dried over anhydrous magnesium sulfate and concentrated, whereby 85g of the objective monomer 2 was obtained as a pale yellow liquid (yield 88%).

[ Chemical formula 5]

Synthesis of Polymer A-1

Monomer 1 was weighed 2.34g, CYCLOMER M (manufactured by Daicel Corporation) was weighed 3.60g, monomer 2 was weighed 4.05g, methyl Ethyl Ketone (MEK) was weighed 18.57g, dimethyl 2,2' -azobis (isobutyric acid) (manufactured by polymerization initiator, FUJIFILM Wako Pure Chemical Corporation) was weighed 3.760g, and stirred at 70℃for 6 hours.

After the reaction, reprecipitation was performed using 500mL of methanol. The resulting solid was dissolved in 15g of MEK, and after adding 5.57g of triethylamine and 0.01g of p-methoxyphenol, the mixture was stirred at 60℃for 4 hours. After the reaction solution was returned to room temperature, reprecipitation was performed using 500mL of methanol and dissolution was performed using 25g of MEK, whereby 5.1g of polymer a-1 was obtained (yield 53%).

In the following reaction scheme, "M100" represents CYCLOMER M100,100. The unit of the content (content ratio) of each structural unit in the polymer is "mol%.

[ Chemical formula 6]

[ Production of Polymer A-2 ]

Synthesis of monomer 3

Monomer 3 was synthesized using (3-mercaptopropyl) trimethoxysilane and 2- (perfluorohexyl) ethyl vinyl ether (CHEM INOX FAVE-6 (UNIMATEC co., ltd.)) according to the method described in Tetrahedron,1991, 47, 4927-4940. In the following structural formula, et represents ethyl.

[ Chemical formula 7]

Synthesis of Polymer A-2

3.90G of monomer 3, 6.59g of 3-glycidoxypropyl trimethoxysilane (manufactured by FUJIFILM Wako Pure Chemical Corporation), 6.93g of 3-methacryloxypropyl trimethoxysilane (manufactured by FUJIFILM Wako Pure Chemical Corporation), 50g of acetone, 1.38g of 5% aqueous potassium carbonate solution, 9.0g of pure water were weighed, and stirred at 50℃for 5 hours. The obtained reaction solution was cooled to room temperature, and 50g of methyl isobutyl ketone (MIBK) and 50g of 5% saline were added to extract an organic layer. After the organic layer was further washed 1 time with 50g of 5% saline and 2 times with 50g of pure water, 10g of magnesium sulfate and 0.01g of p-methoxyphenol were added. After filtering out magnesium sulfate, the solvent was distilled off under reduced pressure at 50℃under 35mmHg, whereby 20.2g of polymer A-2 was obtained as a 60.5 mass% MIBK solution (yield 95%).

In the following structural formula, me represents methyl group, et represents ethyl group. The unit of the content (content ratio) of each structural unit in the polymer is "mol%.

[ Chemical formula 8]

[ Production of Polymer A-3 ]

Polymer A-3 was produced in the same manner as in Polymer A-1 except that 25.0g of 1H, 2H-perfluorooctanol used in the synthesis of body 1 was changed to 18.1g of 1H, 2H-perfluorohexanol in the production of Polymer A-1.

[ Production of Polymer A-4 ]

In the production of the polymer A-2, the polymer A-4 was produced in the same manner as the polymer A-2 except that 2- (perfluorohexyl) ethyl vinyl ether (CHEMINOX FAVE-6 (UNIMATEC CO., LTD. Manufactured)) used in the synthesis of the monomer 3 was changed to 2- (perfluorobutyl) ethyl vinyl ether (CHEMINOX FAVE-4 (UNIMATEC CO., LTD. Manufactured)).

[ Production of Polymer A-5 ]

Synthesis of Polymer A-5

2.34G of monomer 1,3.60gCYCLOMER M100 (manufactured by Daicel Corporation), 4.05g of the above-mentioned monomer 2, 18.57g of Methyl Ethyl Ketone (MEK), 3.760g of dimethyl 2,2' -azobis (isobutyric acid) (manufactured by polymerization initiator, FUJIFILM Wako Pure Chemical Corporation) were mixed, and stirred at 70℃for 6 hours.

After the reaction, reprecipitation was performed using 500mL of methanol. The resulting solid was dissolved in 15g of MEK, and 5.57g of triethylamine and 0.01g of p-methoxyphenol were added. Thereafter, a solution containing 6.12g of tetraethyleneglycol bis (3-mercaptopropionate) (EGMP-4, SC organic IC CHEMICAL co., manufactured by ltd.) and 6.12g of mek was added thereto over 2 hours while heating to 60 ℃. Further, the reaction mixture was stirred at 60℃for 4 hours, and then, the reaction mixture was recovered to room temperature, and then, reprecipitated using 500mL of methanol. The resulting solid was dissolved with 25g of MEK to obtain polymer A-5.

The difference in SP value between the LC-A, the LC-B, or the LC-C and the polymer Av1, the polymer A-2, the polymer A-3, the polymer A-4, or the polymer A-5 (compound having A functional group) is 5MPA ^0.5 or less.

< Third component >

C-1: the following mixture was added as the third component C-1 in the mass ratio shown in Table 1.

Tricyclodecane dimethanol diacrylate (a-DCP, shin-Nakamura Chemical co., ltd.; multifunctional monomer): 46 parts by mass

IRGACURE290 (manufactured by BASF corporation): 3 parts by mass

The difference in SP value between C-1 and LC-A, LC-B or LC-C is 5MPA ^0.15 or less.

[ Filler ]

F-1: liquid crystal polymer particles produced by the following production method

LC-D production

To a reactor equipped with a stirrer, a torque meter, a nitrogen inlet tube, a thermometer and a reflux condenser, 1034.99g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 378.33g (1.75 mol) of 2, 6-naphthalenedicarboxylic acid, 83.07g (0.5 mol) of terephthalic acid, 272.52g (2.475 mol) of hydroquinone, an excess amount of 0.225 mol relative to the total mole amount of 2, 6-naphthalenedicarboxylic acid and terephthalic acid, 1226.87g (12 mol) of acetic anhydride and 0.17g of 1-methylimidazole as a catalyst were added. After the gas in the reactor was replaced with nitrogen, the temperature was raised from room temperature to 145℃over 15 minutes while stirring under a nitrogen stream, and the mixture was refluxed at 145℃for 1 hour.

Then, while distilling the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 145℃to 310℃over 3 hours and 30 minutes, and after holding at 310℃for 3 hours, the liquid crystalline polyester (LC-D) was taken out in a solid state, and the liquid crystalline polyester (LC-D) was cooled to room temperature. The flow initiation temperature of the polyester (LC-D) was 265 ℃.

Production of liquid Crystal Polymer particles (F-1)

The liquid crystal polyester (LC-D) was pulverized using a jet mill (Kurimoto, ltd. Manufactured "KJ-200"), to obtain fine particles of the liquid crystal polyester (liquid crystal polymer particles (F-1)). The average particle diameter of the fine particles of the liquid crystal polyester was 9. Mu.m.

F-2: the amount of the solid component was set to the amount shown in Table 1 by using silica fine particles (manufactured by SO-C2, ADMATECHS CO MPANY LIMITED) having an average particle diameter of 0.5 μm, which are commercially available.

F-3: copolymer (PFA) particles of tetrafluoroethylene and perfluoroalkoxyethylene having a melting point of 280 ℃, an average particle diameter of 0.2 μm to 0.5 μm and a dielectric loss tangent of 0.001

F-4: commercially available hollow powder (Glass foam iM30K, 3M manufactured by Japan Limited) having an average particle diameter of 16 μm

F-5: boron nitride particles having a melting point of >500 ℃, HP40MF100 (Mizushima Ferroalloy co., ltd.) and a dielectric loss tangent of 0.0007

Examples 1 to 20 and comparative example 1

< Film Forming >

The methods described in table 1 were selected from the following multilayer coating a and multilayer coating B, single layer coating, and co-casting.

[ Multilayer coating A ]

Preparation of the Polymer solution

A polymer having a dielectric loss tangent of 0.005 or less was added to N-methylpyrrolidone, and the mixture was stirred under a nitrogen atmosphere at 140℃for 4 hours to dissolve the polymer. Thereafter, as described in Table 1, the compound having a functional group and the third component were added as needed, and stirred at 25℃for 30 minutes to obtain respective polymer solutions. The solid content concentration was 10 mass% of the polymer solution for layer a (core layer) and 5 mass% of the polymer solution for layer B (skin layer).

Then, first, the polymer solution for layer A and the polymer solution for layer B were obtained by passing the polymer solution through a sintered fiber metal filter having a nominal pore size of 5. Mu.m, and then, similarly, passing the polymer solution through a sintered fiber metal filter having a nominal pore size of 5. Mu.m.

In addition, in the case where the additive is insoluble in N-methylpyrrolidone, a liquid crystal polymer solution is prepared without adding the additive, and after passing through the sintered fiber metal filter, the additive is added and stirred.

Membrane production

The obtained polymer solutions for layer a (core layer) and layer B (skin layer) were transferred to a slot die coater equipped with a slide coater, and a film having a 3-layer structure (skin layer/core layer/skin layer) was coated on the treated surface of copper foil (FUKUDA METAL FOIL & PO WDER co., ltd. Manufactured, CF-T9DA-SV-18, thickness 18 μm). The solvent was removed from the coated film by drying at 40 ℃ for 4 hours to obtain a polymer film.

[ Multilayer coating B ]

Preparation of the Polymer solution

The polymers described in table 1 and the additives described in table 1 were added to toluene so that the solid content concentration became 80%, and the mixture was stirred for 60 minutes to obtain polymer solutions for layer a and layer B, respectively.

Membrane production

The polymer solutions for layer A and layer B were fed to a slot die coater equipped with a slide coater on a treated surface of copper foil (FUKUDA METAL FOIL & POWDER CO., LTD. Manufactured by CF-T9DA-SV-18, thickness 18 μm, surface roughness Rz0.85 μm of the treated surface) to perform multilayer coating. After drying at 100℃for 3 minutes, the solvent was removed from the coating film by drying at 170℃for 3 minutes, and then the temperature was raised from room temperature to 200℃at 1℃per minute, and the heat treatment was performed at that temperature for 2 hours, to obtain a polymer film (laminate) having a copper layer.

[ Single layer coating ]

Preparation of the Polymer solution

A polymer having a dielectric loss tangent of 0.005 or less was added to N-methylpyrrolidone, and the mixture was stirred under a nitrogen atmosphere at 140℃for 4 hours to dissolve the polymer. Thereafter, a compound having a functional group and a third component were added in the mass ratio shown in table 1, and stirred at 25 ℃ for 30 minutes to obtain a polymer solution. The solid content concentration was set at 10 mass%.

Next, first, it was passed through a sintered fiber metal filter having a nominal pore size of 5 μm, and then, it was also passed through a sintered fiber metal filter having a nominal pore size of 5 μm, to obtain a polymer solution.

Membrane production

The resulting polymer solution was fed to a slot die coater and coated on a treated surface of copper foil (FUKU DA METAL FOIL & POWDER CO., LTD. Manufactured, CF-T9DA-SV-18, thickness 18 μm). The solvent was removed from the coated film by drying at 40 ℃ for 4 hours to obtain a polymer film.

[ Co-casting ]

Preparation of the Polymer solution

The polymer described in Table 1 was added to N-methylpyrrolidone, and after dissolving it by stirring at 140℃for 4 hours under a nitrogen atmosphere, it was passed through a sintered fiber metal filter having a nominal pore size of 10. Mu.m, and then, it was passed through a sintered fiber metal filter having a nominal pore size of 10. Mu.m. Next, the additives described in Table 1 were added in the mass ratios shown in Table 1, and stirred at 25℃for 30 minutes, thereby obtaining a polymer solution.

Membrane production

The resulting polymer solutions for layer a and layer B were transferred to a casting die equipped with a multi-manifold for co-casting adjusted to a 3-layer structure (layer B/layer a/layer B) and cast onto a treated surface of copper foil (FUKUDA METAL FOIL & POWDER CO., LTD. Manufactured, CF-T9DA-SV-18, thickness 18 μm, surface roughness Rz0.85 μm of the adhering surface (treated surface)). The solvent was removed from the casting film by drying at 60℃for 4 hours to obtain a polymer film.

< Polymerization reaction >

After the end of the drying, the polymer film containing C-1 as the third component was irradiated with ultraviolet light having an irradiation dose of 300mJ/cm ² using an air-cooled metal halide lamp (EYE GRAPHICS Co., ltd.) to polymerize the polyfunctional monomer (polyfunctional reactive compound) in C-1 to form a three-dimensional crosslinked structure. Therefore, the cured product of the polyfunctional monomer is contained in the polymer film.

< Production of copper-clad laminate >

[ Metal layer Forming Process ]

Copper clad laminate precursor procedure

Copper foil (FUKUDA METAL FOIL & POWDER CO., LTD. Manufactured, CF-T9DA-SV-18, thickness 18 μm) was placed in contact with the polymer film, and a lamination process was performed for 1 minute at 140℃and a lamination pressure of 0.4MPa using a laminator (Nikko-Materials Co., ltd. Manufactured "vacuum laminator V-130"), to obtain a copper-clad laminate precursor.

The hot-press bonding process

The obtained copper-clad laminate precursor was thermally bonded for 10 minutes at 300 ℃ under 4.5MPa using a thermal bonding machine (Toyo Seiki Seisaku-sho, ltd. Manufactured "MP-SNL"), thereby producing a copper-clad laminate (laminate).

Annealing process-

The resulting copper-clad laminate was then heated from room temperature (25 ℃) to 280℃at 1℃per minute under a nitrogen atmosphere. The copper-clad laminate (laminate) was obtained by performing heat treatment at 280℃for 2 hours.

Evaluation (evaluation)

The polymer film thus produced was evaluated by the method described above, and the results are shown in table 1.

The polymer films of examples 1 to 20 were polymer films having higher concentrations of the compound having a functional group in the surfaces on both sides than the inside. Further, it was confirmed that the surface coverage of the compound having a functional group on both surfaces of the polymer film of example 2 was 100 area%.

On the other hand, the polymer film of comparative example 1 did not contain a compound having a functional group, and there was no concentration difference between the surface and the inside thereof.

The surface coverage of the compound having a functional group on both surfaces of the polymer films of examples 1 and 3 was 50 area% or more.

On the other hand, in the polymer film of comparative example 1, the surface coverage of the compound having a functional group was 0 area%.

From the results shown in table 1, the polymer films according to the present invention, i.e., the polymer films of examples 1 to 20, have more excellent adhesion to the substrate than the polymer film of comparative example 1.

On the other hand, the polymer film of comparative example 1 containing no compound having a functional group was insufficient in peel strength and poor in adhesion to the substrate.

From the results shown in table 1, the polymer films of examples 1 to 19 as the polymer films according to the present invention were polymer films having low dielectric loss tangent.

Claims

1.A polymer film, comprising:

A polymer having a dielectric loss tangent of 0.005 or less; and

A compound having a functional group which is capable of reacting,

The concentration of the compound having a functional group in at least one surface of the polymer film is 2 to 200 times higher than the concentration of the compound having a functional group in the inside,

The polymer having a dielectric loss tangent of 0.005 or less comprises a liquid crystal polymer,

The compound having a functional group contains a silicon atom or a fluorine atom,

The polymer film having a layer A and a layer B on at least one surface of the layer A, the layer B comprising the compound having a functional group,

The layer B contains a third component in which the compound having a functional group is immobilized on the polymer having a dielectric loss tangent of 0.005 or less,

The third component comprises a cured product of a polyfunctional reactive compound which is a polyfunctional (meth) acrylate compound,

The third component includes a polymer having a functional group that interacts with the compound having a functional group and that is compatible with the polymer having a dielectric loss tangent of 0.005 or less.

2. A polymer film, comprising:

A polymer having a dielectric loss tangent of 0.005 or less; and

A compound having a functional group which is capable of reacting,

The surface coating rate of the compound having a functional group in at least one surface of the polymer film is 50 area% or more,

3. The polymer film according to claim 1 or 2, wherein,

The functional group is at least one group selected from the group consisting of a covalently-bondable group, an ionically-bondable group, a hydrogen-bondable group, and a dipole-interactable group.

4. The polymer film of claim 3, wherein,

The functional group is a covalently-bondable group.

5. The polymer film of claim 4, wherein,

The covalently-bondable group is at least one group selected from the group consisting of an epoxy group, an oxetanyl group, an isocyanate group, an acid anhydride group, a carbodiimide, an N-hydroxy ester group, a glyoxal group, an imide ester group, a haloalkyl group, and a thiol group.

6. The polymer film according to claim 1 or 2, wherein,

The difference between the Hoy-method-based SP value of the polymer having a dielectric loss tangent of 0.005 or less and the Hoy-method-based SP value of the compound having a functional group is 5MPa ^0.5 or less.

7. The polymer film of claim 1, wherein,

The content of the third component in the layer B is greater than the content of the third component in the layer a.

8. The polymer film of claim 1, further having a layer C,

The polymer film has the layer B, the layer a, and the layer C in this order.

9. The polymer film according to claim 1 or 2, wherein,

The linear expansion coefficient of the polymer film is-20 ppm/K to 50ppm/K.

10. The polymer film according to claim 1 or 2, wherein,

The dielectric loss tangent of the polymer film is 0.01 or less.

11. The polymer film according to claim 1 or 2, wherein,

The polymer film includes a filler.

12. The polymer film of claim 11, wherein,

The filler has a number density in the interior of the polymer film that is greater than a number density at the surface of the polymer film.

13. The polymer film of claim 1, wherein,

The polymer having a dielectric loss tangent of 0.005 or less comprises a liquid crystal polymer having a structural unit represented by any one of the formulas (1) to (3),

Formula (1) -O-Ar ¹ -CO-

Formula (2) -CO-Ar ² -CO-

Formula (3) -X-Ar ³ -Y-

In the formulae (1) to (3), ar ¹ represents phenylene, naphthylene or biphenylene, ar ² and Ar ³ each independently represent phenylene, naphthylene, biphenylene or a group represented by the following formula (4), X and Y each independently represent an oxygen atom or an imino group, a hydrogen atom in Ar ¹～Ar³ is optionally substituted with a halogen atom, an alkyl group or an aryl group,

Formula (4) -Ar ⁴-Z-Ar⁵ -

14. A polymer film, comprising:

a liquid crystal polymer; and

A compound having a functional group which is capable of reacting,

The layer B comprises a third component which immobilizes the compound having a functional group on the liquid crystal polymer,

The third component comprises a polymer having a functional group that interacts with the compound having a functional group and is compatible with the liquid crystal polymer.

15. A polymer film, comprising:

a liquid crystal polymer; and

A compound having a functional group which is capable of reacting,

16. A laminate having the polymer film according to any one of claims 1 to 15 and a metal layer in which the concentration of the compound having a functional group is higher than that of the inner face, which is disposed in the polymer film.

17. The laminate according to claim 16, which has metal layers respectively disposed on both sides of the polymer film.

18. The laminate according to claim 16, wherein,

The metal layer is a copper layer,

The peel strength of the polymer film and the copper layer is 0.5kN/m or more.

19. The laminate according to claim 16, wherein,

The metal layer is disposed on the layer B.