Films and laminates

Abstract

To provide a film and a laminate that are excellent in strength and have a low dielectric loss tangent compared to the related art.SOLUTION: A film includes a liquid crystal polymer and a filler, and has a melting calorie equal to or greater than 0.5 J / g. Applications thereof are also provided.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to films and laminates. [Background technology]

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

[0003] For example, Patent Document 1 describes a liquid crystal polyester film comprising at least liquid crystal polyester, wherein when the first degree of orientation is defined as the degree of orientation in a first direction parallel to the main surface of the liquid crystal polyester film, and the second degree of orientation is defined as the degree of orientation in a second direction parallel to the main surface and perpendicular to the first direction, the ratio of the first degree of orientation to the second degree of orientation, i.e., the first degree of orientation / second degree of orientation, is 0.95 or more and 1.04 or less, and the third degree of orientation of the liquid crystal polyester, measured by wide-angle X-ray scattering in a direction parallel to the main surface, is 60.0% or more. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-026474 [Overview of the project] [Problems that the invention aims to solve]

[0005] The problem that one embodiment of the present invention aims to solve is to provide a film and a laminate that have excellent strength and a lower dielectric loss tangent compared to conventional films and laminates. [Means for solving the problem]

[0006] The means for solving the above problems include the following embodiments. <1> A film containing a liquid crystal polymer and a filler, with a heat of fusion of 0.5 J / g or more. <2> Liquid crystal polymers include aromatic polyesteramides. <1> The film described above. <3> Aromatic polyesteramides include the constituent units represented by the following formula 1, the constituent units represented by the following formula 2, and the constituent units represented by the following formula 3. With respect to the total content of the constituent units represented by Formula 1, Formula 2, and Formula 3, The content of the constituent units represented by Equation 1 is 30 mol% to 80 mol%, The content of the constituent units represented by Equation 2 is between 10 mol% and 35 mol%, The content of the constituent unit represented by Equation 3 is between 10 mol% and 35 mol%. <2> The film described above. -O-Ar 1 -CO- …Formula 1 -CO-Ar 2 -CO- …Formula 2 -NH-Ar 3 -O- …Formula 3 In formulas 1 to 3, Ar 1 Ar 2 , and Ar 3 Each of these independently represents a phenylene group, a naphthylene group, or a biphenylylene group. <4> The filler includes an inorganic filler containing at least one selected from the group consisting of boron nitride, titanium dioxide, and silicon dioxide. <1> ~ <3> The film described in one of the following. <5> The filler includes an organic filler containing at least one selected from the group consisting of liquid crystal polyester, polytetrafluoroethylene, and polyethylene. <1> ~ <4> The film described in one of the following. <6> The filler contains hollow particles. <1> ~ <5> The film described in one of the following. <7> The filler includes liquid crystal polymer particles, silica particles, or hollow glass particles. <1> ~ <6> The film described in one of the following. <8> The liquid crystal polymer particles include liquid crystal polymer particles whose surfaces have been oxidized. <7> The film described above. <9> The filler content is 30% to 80% by volume relative to the total volume of the film. <1> ~ <8> The film described in one of the following. <10> <1> ~ <9> A laminate comprising a film as described in any one of the above, and a metal layer or metal wiring disposed on at least one surface of the film. [Effects of the Invention]

[0007] According to one embodiment of the present invention, a film and a laminate are provided that have excellent strength and a lower dielectric loss tangent compared to conventional films. [Modes for carrying out the invention]

[0008] The contents of this disclosure are described in detail below. The descriptions of the constituent elements described below may be based on representative embodiments of this disclosure, but this disclosure is not limited to such embodiments. In this specification, the "~" symbol indicating a numerical range is used to mean that the numbers before and after it are included as the lower and upper limits, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples. Furthermore, in the notation of groups (atomic groups) in this specification, the notation that does not specify whether they are substituted or unsubstituted includes both those with and without substituents. For example, "alkyl group" includes not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups). Furthermore, in the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. Also, unless otherwise specified, the weight average molecular weight (Mw) and number average molecular weight (Mn) in the present disclosure are molecular weights converted using polystyrene as a standard substance, detected by a differential refractometer, with a solvent of PFP (pentafluorophenol) / chloroform = 1 / 2 (mass ratio), using a gel permeation chromatography (GPC) analyzer with a column of TSKgel SuperHM-H (trade name of Tosoh Corporation).

[0009] [Film] The film of the present disclosure contains a liquid crystal polymer and a filler, and has a heat of fusion of 0.5 J / g or more.

[0010] As a result of intensive studies by the present inventors, it has been found that by adopting the above configuration, a film excellent in strength and having a lower dielectric tangent compared to the conventional ones can be provided.

[0011] Although the detailed mechanism by which the above effects are obtained is unclear, it is presumed as follows.

[0012] Since the film of the present disclosure contains a filler, it is considered to be excellent in strength. Also, since the heat of fusion is 0.5 J / g or more, it is considered that the amount of crystals in the film is large, and the mobility of the amorphous part decreases, resulting in a decrease in the dielectric tangent. <00!00105> On the other hand, it has been found that the film described in Patent Document 1 does not contain a filler, and cracks, breaks, etc. may occur in the manufacturing process of processing into products such as circuit boards, or in the processed products.

[0014] (Liquid Crystal Polymer) The film of the present disclosure contains a liquid crystal polymer (Liquid Crystal Polymer: LCP).

[0015] <000!0113>In the present disclosure, the type of the liquid crystal polymer is not particularly limited, and known liquid crystal polymers can be used. Furthermore, the liquid crystal polymer may be a thermotropic liquid crystal polymer that exhibits liquid crystallinity in a molten state, or a lyotropic liquid crystal polymer that exhibits liquid crystallinity in a solution state. If the liquid crystal polymer is a thermotropic liquid crystal polymer, it is preferable that it is a liquid crystal polymer that melts at a temperature of 450°C or lower. Examples of liquid crystal polymers include liquid crystal polyester, liquid crystal polyesteramide (in which amide bonds are introduced into liquid crystal polyester), liquid crystal polyester ether (in which ether bonds are introduced into liquid crystal polyester), and liquid crystal polyester carbonate (in which carbonate bonds are introduced into liquid crystal polyester). Furthermore, from the viewpoint of liquid crystalline properties, the liquid crystal polymer is preferably a polymer having an aromatic ring, and more preferably an aromatic polyester or an aromatic polyesteramide. Furthermore, the liquid crystal polymer may be a polymer in which an aromatic polyester or aromatic polyesteramide is further modified by introducing isocyanate-derived bonds such as imide bonds, carbodiimide bonds, and isocyanurate bonds. Furthermore, it is preferable that the liquid crystal polymer is a fully aromatic liquid crystal polymer made using only aromatic compounds as raw material monomers.

[0016] Examples of liquid crystal polymers include the following: 1) A compound obtained by polycondensing (i) an aromatic hydroxycarboxylic acid, (ii) an aromatic dicarboxylic acid, and (iii) at least one compound selected from the group consisting of aromatic diols, aromatic hydroxyamines, and aromatic diamines. 2) A compound formed by polycondensation of multiple types of aromatic hydroxycarboxylic acids. 3) A compound obtained by polycondensing (i) an aromatic dicarboxylic acid with (ii) at least one compound selected from the group consisting of aromatic diols, aromatic hydroxyamines, and aromatic diamines. 4) A material obtained by polycondensing (i) a polyester such as polyethylene terephthalate and (ii) an aromatic hydroxycarboxylic acid. Here, aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, aromatic hydroxyamine, and aromatic diamine may each be independently replaced with polycondensable derivatives.

[0017] For example, aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid esters and aromatic dicarboxylic acid esters by converting the carboxyl group to an alkoxycarbonyl group or an aryloxycarbonyl group. By converting the carboxyl group to a haloformyl group, aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid halogens and aromatic dicarboxylic acid halogens. By converting the carboxyl group to an acyloxycarbonyl group, aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid anhydrides and aromatic dicarboxylic acid anhydrides. Examples of polymerizable derivatives of compounds having a hydroxyl group, such as aromatic hydroxycarboxylic acids, aromatic diols, and aromatic hydroxyamines, include those obtained by acyling the hydroxyl group to convert it into an acyloxy group (acylated compounds). For example, by acyling a hydroxyl group to convert it into an acyloxy group, aromatic hydroxycarboxylic acids, aromatic diols, and aromatic hydroxyamines can be replaced with acylated compounds, respectively. Examples of polymerizable derivatives of compounds having an amino group, such as aromatic hydroxyamines and aromatic diamines, include those obtained by acyling the amino group to convert it into an acylamino group (acylated compounds). For example, aromatic hydroxyamines and aromatic diamines can be replaced with acylated products by acyling the amino group to convert it into an acylamino group.

[0018] The liquid crystal polymer is preferably a crystalline polymer (for example, an aromatic polyesteramide as described later). The crystalline nature of the liquid crystal polymer contained in the film further reduces the dielectric loss tangent. Crystalline polymers, in differential scanning calorimetry (DSC), are those that exhibit a clear endothermic peak rather than a stepwise change in endothermic quantity. Specifically, this means that, for example, the full width at half maximum (FWHM) of the endothermic peak measured at a heating rate of 10°C / min is within 10°C. Polymers with a FWHM exceeding 10°C and polymers that do not exhibit a clear endothermic peak are classified as amorphous polymers and distinguished from crystalline polymers.

[0019] The melting point of the liquid crystal polymer is preferably 250°C or higher, more preferably 250°C to 350°C, and even more preferably 260°C to 330°C.

[0020] The melting point is measured using a differential scanning calorimetry analyzer.

[0021] The liquid crystal polymer preferably has a heat of fusion of 0.5 J / g or more, more preferably 2.2 J / g or more, and more preferably 4.0 J / g or more. The upper limit of the heat of fusion is not particularly limited, and is, for example, 10.0 J / g. The method for measuring the heat of fusion is the same as the method for measuring the heat of fusion of the film described later.

[0022] The weight-average molecular weight of the liquid crystal polymer is preferably 1,000,000 or less, more preferably 3,000 to 300,000, even more preferably 5,000 to 100,000, and particularly preferably 5,000 to 30,000.

[0023] From the viewpoint of further reducing the dielectric loss tangent, the liquid crystal polymer preferably contains an aromatic polyesteramide. An aromatic polyesteramide is a resin having at least one aromatic ring and having ester bonds and amide bonds. In particular, from the viewpoint of heat resistance, the aromatic polyesteramide contained in the resin layer is preferably a fully aromatic polyesteramide.

[0024] The aromatic polyester amide preferably contains 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. -O-Ar 1 -CO- … Formula 1 -CO-Ar 2 -CO- … Formula 2 -NH-Ar 3 -O- … Formula 3 In Formulas 1 to 3, Ar 1 , Ar 2 , and Ar 3 each independently represents a phenylene group, a naphthylene group, or a biphenylylene group. Hereinafter, the structural unit represented by Formula 1 and the like are also referred to as "Unit 1" and the like.

[0025] Unit 1 can be introduced, for example, by using an aromatic hydroxycarboxylic acid as a raw material. Unit 2 can be introduced, for example, by using an aromatic dicarboxylic acid as a raw material. Unit 3 can be introduced, for example, by using an aromatic hydroxylamine as a raw material.

[0026] Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, and the aromatic hydroxylamine may each independently be replaced with a polycondensable derivative.

[0027] For example, by converting a carboxy group into an alkoxycarbonyl group or an aryloxycarbonyl group, the aromatic hydroxycarboxylic acid and the aromatic dicarboxylic acid can be replaced with an aromatic hydroxycarboxylic acid ester and an aromatic dicarboxylic acid ester. By converting a carboxy group into a halocarbonyl group, the aromatic hydroxycarboxylic acid and the aromatic dicarboxylic acid can be replaced with an aromatic hydroxycarboxylic acid halide and an aromatic dicarboxylic acid halide. By converting the carboxyl group to an acyloxycarbonyl group, aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid anhydrides and aromatic dicarboxylic acid anhydrides. Examples of polycondensable derivatives of compounds having a hydroxyl group, such as aromatic hydroxycarboxylic acids and aromatic hydroxyamines, include those obtained by acyling the hydroxyl group to convert it into an acyloxy group (acylated compounds). For example, aromatic hydroxycarboxylic acids and aromatic hydroxylamines can be replaced with acylated products by acyling the hydroxyl group to convert it into an acyloxy group. Examples of polycondensable derivatives of aromatic hydroxylamines include those obtained by acylation of the amino group to an acylamino group (acylated compounds). For example, aromatic hydroxyamines can be replaced with acylated compounds by acyling the amino group to convert it into an acylamino group.

[0028] In formula 1, Ar 1 The group is preferably a p-phenylene group, a 2,6-naphthylene group, or a 4,4'-biphenylylene group, and more preferably a 2,6-naphthylene group.

[0029] Ar 1 When is a p-phenylene group, unit 1 is a constituent unit derived, for example, from p-hydroxybenzoic acid. Ar 1 When is a 2,6-naphthylene group, unit 1 is a constituent unit derived, for example, from 6-hydroxy-2-naphthoic acid. Ar 1 If the group is a 4,4'-biphenylylene group, then unit 1 is a constituent unit derived, for example, from 4'-hydroxy-4-biphenylcarboxylic acid.

[0030] In formula 2, Ar 2 The group is preferably a p-phenylene group, an m-phenylene group, or a 2,6-naphthylene group, and more preferably an m-phenylene group.

[0031] Ar 2 If the group is a p-phenylene group, then unit 2 is a constituent unit derived from, for example, terephthalic acid. Ar 2 If the m-phenylene group is present, then unit 2 is a constituent unit derived, for example, from isophthalic acid. Ar 2 If the group is a 2,6-naphthylene group, then unit 2 is a constituent unit derived, for example, from 2,6-naphthalenedicarboxylic acid.

[0032] In formula 3, Ar 3 The group is preferably a p-phenylene group or a 4,4'-biphenylene group, and more preferably a p-phenylene group.

[0033] Ar 3 If the first unit is a p-phenylene group, then unit 2 is a constituent unit derived from, for example, p-aminophenol. Ar 3 If the group is a 4,4'-biphenylylene group, then unit 2 is a constituent unit derived from, for example, 4-amino-4'-hydroxybiphenyl.

[0034] The content of Unit 1 is preferably 30 mol% or more, the content of Unit 2 is preferably 35 mol% or less, and the content of Unit 3 is preferably 35 mol% or less, relative to the total content of Unit 1, Unit 2, and Unit 3. The content of Unit 1 is more preferably 30 mol% to 80 mol%, even more preferably 30 mol% to 60 mol%, and particularly preferably 30 mol% to 40 mol%, relative to the total content of Unit 1, Unit 2, and Unit 3. The content of Unit 2 is preferably 10 mol% to 35 mol%, more preferably 20 mol% to 35 mol%, and particularly preferably 30 mol% to 35 mol%, relative to the total content of Unit 1, Unit 2, and Unit 3. The content of Unit 3 is preferably 10 mol% to 35 mol%, more preferably 20 mol% to 35 mol%, and particularly preferably 30 mol% to 35 mol%, relative to the total content of Unit 1, Unit 2, and Unit 3. The total content of each constituent unit is the sum of the amount of substance (moles) of each constituent unit. The amount of substance of each constituent unit is calculated by dividing the mass of each constituent unit that makes up the aromatic polyester amide by the formula weight of each constituent unit.

[0035] The ratio of the content of unit 2 to the content of unit 3, when expressed as [content of unit 2] / [content of unit 3] (moles / moles), is preferably 0.9 / 1 to 1 / 0.9, more preferably 0.95 / 1 to 1 / 0.95, and even more preferably 0.98 / 1 to 1 / 0.98.

[0036] Furthermore, the aromatic polyesteramide may contain two or more independent units 1 to 3. The aromatic polyesteramide may also contain other constituent units besides units 1 to 3. The content of other constituent units is preferably 10 mol% or less, more preferably 5 mol% or less, relative to the total content of all constituent units.

[0037] Aromatic polyesteramides are preferably produced by melt polymerization of raw material monomers corresponding to the constituent units of the aromatic polyesteramide.

[0038] The film of this disclosure may contain only one aromatic polyesteramide or two or more aromatic polyesteramides.

[0039] The aromatic polyesteramide content is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, based on the total amount of film. The upper limit of the aromatic polyesteramide content is not particularly limited and may be 100% by mass.

[0040] (Filler) The film relating to this disclosure includes fillers.

[0041] The filler may be particulate or fibrous, and may be inorganic or organic.

[0042] As the inorganic filler, known inorganic fillers can be used. Examples of inorganic filler materials include boron nitride (BN), aluminum oxide (Al2O3), aluminum nitride (AlN), titanium dioxide (TiO2), silicon dioxide (SiO2), barium titanate, strontium titanate, aluminum hydroxide, calcium carbonate, and materials containing two or more of these.

[0043] In particular, the inorganic filler preferably contains at least one selected from the group consisting of boron nitride, titanium dioxide, and silicon dioxide, from the viewpoint of reducing the dielectric loss tangent of the film, and more preferably contains silicon dioxide (so-called silica particles). Furthermore, the inorganic filler may be hollow particles. As the inorganic filler with an internal hollow structure, hollow particles containing silicon dioxide (glass hollow particles) are preferred. For example, the Glass Bubbles series manufactured by 3M Japan (e.g., Glass Bubbles S60HS, etc.) can be used. The inorganic filler is preferably silica particles, which are solid particles containing silicon dioxide, or glass hollow particles, which are hollow particles containing silicon dioxide.

[0044] The average particle size of the inorganic filler is preferably 5 nm to 40 μm, more preferably 1 μm to 35 μm, even more preferably 5 μm to 35 μm, and particularly preferably 10 μm to 35 μm, from the viewpoint of thermal expansion coefficient and adhesion to metal. If the particles or fibers are flattened, the length in the short side direction is indicated. The average particle size of an inorganic filler is the particle size (D50) at which the volume accumulation from the smaller diameter side reaches 50% in a volume-based particle size distribution. D50 can be measured using a scanning electron microscope (SEM).

[0045] As the organic filler, known organic fillers can be used. Examples of organic filler materials include polyethylene, polystyrene, urea-formaldehyde filler, polyester, cellulose, acrylic resin, fluororesin, cured epoxy resin, crosslinked benzoguanamine resin, crosslinked acrylic resin, liquid crystal polymer (LCP), and materials containing two or more of these.

[0046] In particular, the organic filler preferably contains at least one selected from the group consisting of liquid crystal polymers, fluororesins, and polyethylene, more preferably contains at least one selected from the group consisting of liquid crystal polyesters, polytetrafluoroethylenes, and polyethylene, and even more preferably contains liquid crystal polyester, from the viewpoint of reducing the dielectric loss tangent of the film. Liquid crystal polymers, a type of organic filler, are liquid crystal polymer particles and are distinct from the liquid crystal polymers contained in films.

[0047] Here, an organic filler containing a liquid crystal polymer (also called liquid crystal polymer particles) can be produced, for example, by polymerizing a liquid crystal polymer and then crushing it in a pulverizer or the like to make it into a powder.

[0048] Furthermore, the organic filler may be in the form of fibers such as nanofibers, or it may be hollow resin particles.

[0049] The average particle size of the organic filler is preferably 5 nm to 20 μm, more preferably 1 μm to 20 μm, even more preferably 5 μm to 15 μm, and particularly preferably 10 μm to 15 μm, from the viewpoint of thermal expansion coefficient and adhesion to metal. The average particle size of an organic filler is the particle size (D50) at which the volume accumulation from the smaller diameter side reaches 50% in a volume-based particle size distribution. D50 can be measured using a scanning electron microscope (SEM).

[0050] From the viewpoint of reducing the dielectric loss tangent of the film, it is preferable that the filler contains hollow particles.

[0051] In particular, the filler is more preferably made of liquid crystal polymer particles, silica particles, or hollow glass particles, from the viewpoint of reducing the dielectric loss tangent of the film.

[0052] From the viewpoint of improving the elongation at break of the film, it is preferable that the liquid crystal polymer particles include liquid crystal polymer particles whose surfaces have been oxidized. There are no particular limitations on the method for producing liquid crystal polymer particles whose surfaces have been oxidized, but it is preferable that the method includes an oxidation treatment step to oxidize the surface of the liquid crystal polymer particles.

[0053] The oxidation treatment step is preferably a step of oxidizing the surface of the liquid crystal polymer particles using an oxidizing agent, and more preferably a step of oxidizing the surface of the liquid crystal polymer particles by bringing the liquid crystal polymer particles into contact with the oxidizing agent in an aqueous solution.

[0054] The pH of the aqueous solution is not particularly limited as long as it can oxidize the liquid crystal polymer particles, but it is preferably 8 or higher, more preferably 12 or higher, and even more preferably 13 or higher. The upper limit of the pH of the aqueous solution is not particularly limited, for example, 14.

[0055] The contact time between the liquid crystal polymer particles and the oxidizing agent in the aqueous solution is preferably 0.1 to 24 hours, more preferably 0.5 to 10 hours, and even more preferably 1.5 to 6 hours.

[0056] Furthermore, the temperature of the aqueous solution when contacting the liquid crystal polymer particles with the oxidizing agent is preferably 1°C to 95°C, more preferably 25°C to 80°C, and even more preferably 45°C to 65°C.

[0057] There are no restrictions on the method of bringing liquid crystal polymer particles into contact with an oxidizing agent in an aqueous solution. Examples include mixing using a crusher or pulverizer such as a rocking mill, piece mill, ball mill, Henschel mixer, jet mill, starburst, or paint conditioner; contacting while stirring using a mechanical stirrer such as a three-one motor or a magnetic stirrer; and contacting a cartridge filled with liquid crystal polymer particles while circulating an aqueous solution of an oxidizing agent containing the oxidizing agent using a pump.

[0058] It is preferable to bring liquid crystal polymer particles into contact with an oxidizing agent in an aqueous solution, and then remove the oxidized particles from the aqueous solution. There are no particular limitations on the method for extracting oxidized particles from an aqueous solution, and known methods can be used. For example, the aqueous solution can be filtered to separate the oxidized particles as a filter. After removing the oxidized particles, it is also preferable to wash them with water, an organic solvent, or the like.

[0059] In the oxidation treatment process, it is preferable to use an oxidizing agent. The above aqueous solution preferably contains an oxidizing agent. There are no restrictions on the oxidizing agent, and examples include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; nitrates such as cerium ammonium nitrate, sodium nitrate, and ammonium nitrate; peroxides such as hydrogen peroxide and tert-butyl hydroperoxide; manganese compounds such as potassium permanganate and manganese dioxide; chromium compounds such as potassium chromate and potassium dichromate; hypervalent iodine compounds such as potassium periodate and sodium periodate; quinone compounds such as p-benzoquinone, 1,2-naphthoquinone, anthraquinone, and chloranil; amine oxide compounds such as N-methylmorpholine N-oxide; salts of halogen oxoacids such as sodium hypochlorite and sodium chlorite; and double salts consisting of potassium peroxymonosulfate, potassium bisulfate, and potassium sulfate (OXONE, manufactured by DuPont).

[0060] In particular, the oxidizing agent is preferably a persulfate, and more preferably a persulfate, from the viewpoint of oxidizing properties, dispersibility, and tensile strength.

[0061] Furthermore, as an oxidizing agent, it is preferable to include at least one compound selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, potassium permanganate, sodium hypochlorite, cerium ammonium nitrate, potassium chromate, potassium dichromate, and double salts consisting of potassium peroxymonosulfate, potassium bisulfate, and potassium sulfate, more preferably to include at least one compound selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, sodium hypochlorite, cerium ammonium nitrate, and double salts consisting of potassium peroxymonosulfate, potassium bisulfate, and potassium sulfate, and particularly preferably to include at least one compound selected from the group consisting of sodium persulfate, potassium persulfate, and ammonium persulfate.

[0062] Furthermore, a catalyst may be used separately from the oxidizing agent to assist the action of the oxidizing agent. Examples of such catalysts include divalent iron compounds (such as FeSO4) and trivalent iron compounds. The oxidizing agent and catalyst may also be hydrates.

[0063] Furthermore, from the viewpoint of oxidizing properties, the standard redox potential of the oxidizing agent is preferably 0.30V or higher, more preferably 1.50V or higher, and even more preferably 1.70V or higher. There is no particular upper limit to the standard redox potential of the oxidizing agent; for example, it is preferably 4.00V or lower, and more preferably 2.50V or lower. The above standard oxidation-reduction potentials are based on a standard hydrogen electrode.

[0064] In the aqueous solution, the content of the oxidizing agent is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 20 parts by mass, and particularly preferably 1 to 20 parts by mass, per 100 parts by mass of water in the aqueous solution. The oxidizing agent may be used alone or in combination of two or more types. When the aqueous solution contains a catalyst, the content of the oxidizing agent is preferably 0.005 parts by mass to 2 parts by mass, more preferably 0.01 parts by mass to 2 parts by mass, and even more preferably 0.1 parts by mass to 2 parts by mass, per 100 parts by mass of water in the aqueous solution. The catalyst may be used alone or in combination of two or more types.

[0065] The aqueous solution may also preferably contain an alkaline compound in addition to the above-mentioned components in order to adjust the pH of the aqueous solution. Examples of alkaline compounds include alkali metal hydroxides (such as sodium hydroxide) and inorganic bases such as alkaline earth metal hydroxides; as well as organic bases. Among these, alkali metal hydroxides are preferred as alkaline compounds. The amount of alkaline compound in the aqueous solution can be adjusted as appropriate so that the pH of the aqueous solution can be adjusted to the desired temperature. For example, it is preferable that the amount is 0.1 to 10 parts by mass per 100 parts by mass of water in the aqueous solution.

[0066] Furthermore, the method for producing liquid crystal polymer particles whose surfaces have been oxidized may include other steps. A method for producing liquid crystal polymer particles whose surface has been oxidized preferably includes a step of preparing the liquid crystal polymer particles to be used in the oxidation treatment step. The liquid crystal polymer particles used in the above oxidation treatment process may be prepared by known methods or commercially available products may be used. Furthermore, the method for producing liquid crystal polymer particles whose surfaces have been oxidized may include a washing step for washing the particles obtained by the oxidation treatment step, and a drying step for drying the particles obtained by the oxidation treatment step or the washing step. There are no particular restrictions on the cleaning method in the cleaning process and the drying method in the drying process; known methods can be used.

[0067] The surface-oxidized liquid crystal polymer particles may contain other additives. Other known additives can be used. Specifically, examples include fillers, leveling agents, defoamers, antioxidants, UV absorbers, flame retardants, and colorants.

[0068] Furthermore, other additives such as resins other than those mentioned above may also be included. Examples of resins other than liquid crystal polymers include thermoplastic resins such as polyolefins, cycloolefin polymers, polyamides, polyesters, polyetherketones, polycarbonates, polyphenylene ethers and their modified products, and polyetherimides; elastomers such as copolymers of glycidyl methacrylate and polyethylene; and thermosetting resins such as phenolic resins, epoxy resins, polyimide resins, and cyanate resins.

[0069] The total content of other additives is preferably 25 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, based on the content of 100 parts by mass of liquid crystal polymer.

[0070] Liquid crystal polymer particles with an oxidized surface may be used individually or in combination of two or more types.

[0071] If the film contains fillers, the filler content is preferably 20% to 80% by volume, and more preferably 40% to 80% by volume, relative to the total volume of the film.

[0072] The films of this disclosure may contain other components besides aromatic polyesteramides and fillers, to the extent that they do not significantly impair the effects of this disclosure. Other known additives can be used as components. Examples of other components include leveling agents, defoaming agents, antioxidants, UV absorbers, flame retardants, and colorants.

[0073] (Physical properties) - Heat of fusion - The heat of fusion of the film disclosed herein is 0.5 J / g or more, preferably 2.2 J / g or more, more preferably 4.0 J / g or more, and even more preferably 7.0 J / g or more. The upper limit of the heat of fusion is not particularly limited, and is, for example, 10.0 J / g.

[0074] In this disclosure, the heat of fusion refers to the amount of heat (latent heat) required for a solid film to undergo a phase transition to a liquid, and is a value measured using a differential scanning calorimeter. For example, the heat of fusion is measured using a "DSC-60A Plus" (manufactured by Shimadzu Corporation). The heating rate in the measurement is set to 10°C / min.

[0075] The film disclosed herein has a high degree of crystallinity and a low dielectric loss tangent because its heat of fusion is 0.5 J / g or more. The heat of fusion of the film disclosed herein can be controlled by appropriately selecting conditions such as the temperature and time during heating and the rate of cooling during cooling.

[0076] -Melting point- The melting point of the film of this disclosure is preferably 300°C to 360°C, and more preferably 320°C to 350°C.

[0077] In this disclosure, the melting point is a value measured using a differential scanning calorimeter. For example, the "DSC-60A Plus" (manufactured by Shimadzu Corporation) can be used as the differential scanning calorimeter. The heating rate during measurement is set to 10°C / min.

[0078] -Ratio of heat of fusion to melting point- From the viewpoint of further reducing the dielectric loss tangent, the film of this disclosure preferably has a ratio of heat of fusion to melting point of 0.007 J / g·℃ or higher. The upper limit of the ratio is not particularly limited, and is, for example, 0.02 J / g·℃ or higher.

[0079] - Dielectric Loss Tangent - The dielectric loss tangent of the film of this disclosure is preferably 0.005 or less, more preferably 0.004 or less, and even more preferably 0.003 or less. In this disclosure, the dielectric loss tangent is measured by the resonant perturbation method at a frequency of 10 GHz. A 10 GHz cavity resonator (CP531, manufactured by Kanto Electronics Applied Development Co., Ltd.) is connected to a network analyzer (E8363B, manufactured by Agilent Technology), a test specimen is inserted into the cavity resonator, and the dielectric loss tangent of the film is measured from the change in the resonant frequency before and after insertion over 96 hours under conditions of 25°C and 60% RH.

[0080] -Thickness- The thickness of the film of this disclosure is preferably 6 μm to 200 μm, more preferably 12 μm to 100 μm, and even more preferably 20 μm to 60 μm, from the viewpoint of strength, dielectric loss tangent, and adhesion to the metal layer.

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

[0082] (Film manufacturing method) The films of this disclosure can be manufactured by known methods. For example, a resin solution or resin dispersion containing aromatic polyesteramide can be applied to a substrate by a casting method to form a resin layer, and then the substrate can be peeled off to obtain the resin layer as a film. By using a metal substrate, a laminate having a metal layer and a resin layer (film) can be obtained. Depending on the purpose, it may not be necessary to peel off the substrate.

[0083] The resin solution preferably contains an aromatic polyester amide and a solvent. The resin dispersion preferably contains an aromatic polyester amide, a filler, and a solvent.

[0084] Examples of solvents include halogenated hydrocarbons such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, 1-chlorobutane, chlorobenzene, and o-dichlorobenzene; halogenated phenols such as p-chlorophenol, pentachlorophenol, and pentafluorophenol; ethers such as diethyl ether, tetrahydrofuran, and 1,4-dioxane; ketones such as acetone and cyclohexanone; esters such as ethyl acetate and γ-butyrolactone; 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; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethyl sulfoxide and sulfolane; and phosphorus compounds such as hexamethylphosphate and tri-n-butyl phosphate.

[0085] In particular, the solvent is preferably an aprotic compound, especially an aprotic compound without halogen atoms, because it is less corrosive and easier to handle. The proportion of the aprotic compound in the total solvent is preferably 50% to 100% by mass, more preferably 70% to 100% by mass, and especially preferably 90% to 100% by mass. Furthermore, the above aprotic compound is preferably an amide such as N,N-dimethylformamide, N,N-dimethylacetamide, tetramethylurea, N-methylpyrrolidone, or an ester such as γ-butyrolactone, as it readily dissolves aromatic polyesteramides, and more preferably N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

[0086] It is preferable to apply a resin solution or resin dispersion onto the substrate and then heat it. The heating temperature is, for example, 40°C to 100°C. The heating time is, for example, 10 minutes to 5 hours.

[0087] It is preferable to form a resin layer on a substrate and then perform an annealing treatment on the laminate containing the substrate and the resin layer. The heat of fusion of the film can be adjusted by the temperature and time of the annealing treatment. In order to make the heat of fusion of the film 2.2 J / g or more, it is preferable to perform the annealing treatment at 250°C to 350°C for 2.5 hours to 10 hours. Furthermore, it is preferable to perform the annealing treatment under an inert gas atmosphere such as nitrogen.

[0088] [Laminated structure] The laminate of the present disclosure preferably includes the film and a metal layer or metal wiring disposed on at least one surface of the film.

[0089] The metal layer or metal wiring may be any known metal layer or metal wiring, and examples of metals include copper, silver, gold, and alloys thereof. Preferably, the metal layer or metal wiring is a copper layer or copper wiring.

[0090] The copper layer is preferably a rolled copper foil formed by a rolling method, or an electrolytic copper foil formed by an electrolytic method.

[0091] The laminate may be manufactured by bonding a film and a metal layer together. There are no particular restrictions on the method of bonding the film and the metal layer; known lamination methods can be used.

[0092] Furthermore, in the above-mentioned method for manufacturing the film, by using a metal substrate as the base material, the laminate can be manufactured without peeling the film from the base material.

[0093] The thickness of the metal layer is not particularly limited, but is preferably 3 μm to 30 μm, and more preferably 5 μm to 20 μm.

[0094] The thickness of the metal layer is calculated using the following method. The laminate is cut with a microtome, and the cross-section is observed with an optical microscope. Three or more cross-sectional samples are cut out, and the thickness of the target layer is measured at three or more points in each cross-section. The average value of the measured values ​​is calculated, and the average thickness is adopted.

[0095] It is preferable to process the metal layer in the laminate of this disclosure into a desired circuit pattern, for example by etching, to form a flexible printed circuit board. There are no particular restrictions on the etching method, and known etching methods can be used. [Examples]

[0096] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to the following examples unless it exceeds the spirit of the disclosure.

[0097] (Synthesis of aromatic polyesteramide A1) In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser, 940.9 g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 377.9 g (2.5 mol) of acetaminophen, 415.3 g (2.5 mol) of isophthalic acid, and 867.8 g (8.4 mol) of acetic anhydride were added. After replacing the gas in the reactor with nitrogen gas, the temperature was raised from room temperature (23°C, the same applies below) to 143°C over 60 minutes while stirring under a nitrogen gas stream, and refluxed at 143°C for 1 hour. Next, while distilling off the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150°C to 300°C over 5 hours, and the mixture was held at 300°C for 30 minutes. After that, the contents were removed from the reactor and cooled to room temperature. The resulting solid was pulverized to obtain powdered aromatic polyesteramide A1a. Aromatic polyesteramide A1a was a total aromatic polyesteramide.

[0098] Aromatic polyesteramide A1a was subjected to solid-phase polymerization under a nitrogen atmosphere by raising the temperature from room temperature to 160°C over 2 hours and 20 minutes, then raising the temperature from 160°C to 180°C over 3 hours and 20 minutes, and holding at 180°C for 5 hours. After cooling, it was then pulverized with a pulverizer to obtain powdered aromatic polyesteramide A1b.

[0099] Aromatic polyesteramide A1b was subjected to solid-phase polymerization under a nitrogen atmosphere by raising the temperature from room temperature to 180°C over 1 hour and 20 minutes, then raising the temperature from 180°C to 240°C over 5 hours, and holding at 240°C for 5 hours. After this, it was cooled to obtain aromatic polyesteramide A1. Aromatic polyesteramide A1 had a solubility of 1% by mass or more in N-methylpyrrolidone at 140°C.

[0100] (Synthesis of aromatic polyesteramide A2) In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser, 941 g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 273 g (2.5 mol) of 4-aminophenol, 415 g (2.5 mol) of isophthalic acid, and 1123 g (11 mol) of acetic anhydride were added. After replacing the gas in the reactor with nitrogen gas, the temperature was raised from room temperature to 150°C over 15 minutes while stirring under a nitrogen gas stream, and the mixture was refluxed at 150°C for 3 hours. Next, while distilling off the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150°C to 320°C over 3 hours and maintained until an increase in viscosity was observed. After that, the contents were removed from the reactor and cooled to room temperature. The resulting solid was pulverized to obtain powdered aromatic polyesteramide A2a.

[0101] Aromatic polyesteramide A2a was subjected to solid-phase polymerization by holding it at 250°C for 3 hours under a nitrogen atmosphere, then cooled, and subsequently pulverized in a pulverizer to obtain powdered aromatic polyesteramide A2. Aromatic polyesteramide A2 had a solubility of 1% by mass or more in N-methylpyrrolidone at 140°C.

[0102] (Preparing the filler) • Liquid crystal polymer particles (LCP particles) B1 • Liquid crystal polymer particles (LCP particles) B2 • Silica particles…Product name "HARIMIC CR10-20", manufactured by Nippon Steel Chemical & Material Co., Ltd., average particle size (D50) 10 μm • Hollow particles…Product name "Glass Bubbles S60HS", manufactured by 3M Japan, average particle size (D50) 30 μm

[0103] LCP particles B1 and LCP particles B2 were manufactured by the following method. -LCP particle B1- In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser, 1034.99 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 3012.05 g (21.8 mol) of 4-hydroxybenzoic acid, 13.71 g (0.08 mol) of terephthalic acid, and acetic anhydride and a metal catalyst were added. After replacing the gas in the reactor with nitrogen gas, the temperature was raised from room temperature to 140°C over 15 minutes while stirring under a nitrogen gas stream, and then refluxed at 140°C for 1 hour. Next, the temperature was raised from 150°C to 330°C over 3 hours and 30 minutes, then the pressure was reduced, and polymerization was carried out while distilling off the by-product acetic acid and unreacted acetic anhydride. After polymerization, the mixture was cooled to room temperature to obtain liquid crystal polymer B1a. Liquid crystal polymer B1a was pulverized using a jet mill (KJ-200, manufactured by Kurimoto Iron Works Co., Ltd.) to obtain liquid crystal polymer particles B1b. 50 parts by mass of liquid crystal polymer particles B1b were added to an aqueous sodium hydroxide solution (NaOH: 40 parts by mass / water: 400 parts by mass) and stirred. After adding sodium persulfate solution (sodium persulfate: 9.6 parts by mass / water: 100 parts by mass), the temperature was raised to 50°C and stirred for a further 3 hours. After cooling to room temperature, the mixture was filtered. After washing with 500 parts of water, the mixture was thoroughly dried at 40°C to obtain LCP particles B1. LCP particles B1 were liquid crystal polymer particles with an oxidized surface. LCP particles B1 had a median diameter (D50) of 15 μm, a dielectric loss tangent of 0.0014, and a melting point of 318°C.

[0104] -LCP particle B2- In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser, 1034.99 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 89.18 g (0.41 mol) of 2,6-naphthalenedicarboxylic acid, 236.06 g (1.42 mol) of terephthalic acid, 341.39 g (1.83 mol) of 4,4-dihydroxybiphenyl, and potassium acetate and magnesium acetate as catalysts were added. After replacing the gas in the reactor with nitrogen gas, acetic anhydride (1.08 molar equivalent relative to the hydroxyl groups) was further added. Under a nitrogen gas stream, the temperature was raised from room temperature to 150°C over 15 minutes while stirring, and then refluxed at 150°C for 2 hours. Next, while distilling off the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150°C to 310°C over 5 hours, and the polymer was removed and cooled to room temperature. The obtained polymer was raised from room temperature to 295°C over 14 hours and solid-phase polymerized at 295°C for 1 hour. After solid-phase polymerization, it was cooled to room temperature over 5 hours to obtain liquid crystal polymer B2a. Liquid crystal polyester B2a was pulverized using a jet mill (KJ-200, manufactured by Kurimoto Iron Works Co., Ltd.) to obtain liquid crystal polymer particles B2b. 50 parts by mass of liquid crystal polymer particles B2b were added to an aqueous sodium hydroxide solution (NaOH: 40 parts by mass / water: 400 parts by mass) and stirred. After adding aqueous sodium persulfate (sodium persulfate: 9.6 parts by mass / water: 100 parts by mass), the temperature was raised to 50°C and stirred for a further 3 hours. After cooling to room temperature, the mixture was filtered. After washing with 500 parts of water, it was thoroughly dried at 40°C to obtain LCP particles B2. LCP particles B2 were liquid crystal polymer particles with an oxidized surface. LCP particles B2 had a median diameter (D50) of 10 μm, a dielectric loss tangent of 0.0007, and a melting point of 334°C.

[0105] (Fabrication of copper-clad laminates) 80 g of aromatic polyesteramide listed in Table 1 was added to 920 g of N-methylpyrrolidone and stirred at 140°C for 4 hours under a nitrogen atmosphere. A resin solution with a solid content of 8.0% by mass was obtained. The fillers listed in Table 1 were mixed with the resin solution in the quantities listed in Table 1, and the mixture was dispersed using an ultrasonic disperser for 15 minutes to obtain a resin dispersion.

[0106] A resin solution or resin dispersion was applied to electrolytic copper foil (product name "CF-T9DA-SV-18", manufactured by Fukuda Metal Foil & Powder Co., Ltd., surface roughness Sa = 0.22 μm), and then dried at 50°C for 3 hours. This formed a 40 μm thick resin layer on the electrolytic copper foil. A laminate in which a resin layer was formed on electrolytic copper foil was annealed in a nitrogen atmosphere at the temperature and time shown in Table 1 to obtain a copper-clad laminate (laminated body).

[0107] The copper layer was etched from the fabricated flexible copper-clad laminate to extract the film. From the extracted film, strip-shaped test pieces measuring 2 cm in width and 8 cm in length were cut. The heat of fusion, melting point, elongation at break, and dielectric loss tangent of the film were measured using the test pieces. The measurement method is as follows. The measurement results are shown in Table 1.

[0108] <Heat of fusion, melting point> The heat of fusion and melting point were measured using a differential scanning calorimeter (product name "DSC-60Plus", manufactured by Shimadzu Corporation). The heating rate during the measurement was 10°C / min.

[0109] <Elongation at break> Using a Toyo Baldwin Co., Ltd. universal tensile testing machine "STM T50BP," the stress on elongation was measured at a tensile speed of 10% / min in a 25°C, 60%RH atmosphere, and the fracture strength was determined.

[0110] <Dielectric loss tangent> The dielectric loss tangent was measured using the resonant perturbation method at a frequency of 10 GHz. A 10 GHz cavity resonator (CP531, manufactured by Kanto Electronics Applied Development Co., Ltd.) was connected to a network analyzer (Agilent Technology "E8363B"). A test specimen was inserted into the cavity resonator, and the dielectric loss tangent of the film was measured from the change in resonant frequency before and after insertion over 96 hours under conditions of 25°C and 60% RH.

[0111] [Table 1]

[0112] As shown in Table 1, in Examples 1 to 9, the films contained a liquid crystal polymer and filler, and since the heat of fusion was 0.5 J / g or more, they exhibited excellent strength and low dielectric loss tangent.

[0113] On the other hand, in Comparative Example 1, the film did not contain fillers, resulting in inferior strength and a high dielectric loss tangent. In Comparative Example 2, the film had a melting heat of less than 0.5 J / g, resulting in inferior strength and a high dielectric loss tangent.

Claims

1. It contains a liquid crystal polymer and filler, and has a heat of fusion of 0.5 J / g or more. The liquid crystal polymer comprises an aromatic polyesteramide. The aromatic polyester amide includes a constituent unit represented by the following formula 1, a constituent unit represented by the following formula 2, and a constituent unit represented by the following formula 3. With respect to the total content of the constituent units represented by formula 1, formula 2, and formula 3, The content of the constituent unit represented by the above formula 1 is 30 mol% to 80 mol%, The content of the constituent unit represented by the above formula 2 is 10 mol% to 35 mol%, The content of the constituent unit represented by formula 3 is 10 mol% to 35 mol%, A film in which the content of constituent units other than the constituent units represented by formula 1, the constituent units represented by formula 2, and the constituent units represented by formula 3 is 10 mol% or less of the total content of all constituent units. -O-Ar 1 -CO- ...Equation 1 -CO-Ar 2 -CO- ...Formula 2 -NH-Ar 3 -O- ...Equation 3 In formulas 1 to 3, Ar1, Ar2, and Ar3 each independently represent a phenylene group, a naphthylene group, or a biphenylylene group.

2. The film according to claim 1, wherein the filler comprises an inorganic filler containing at least one selected from the group consisting of boron nitride, titanium dioxide, and silicon dioxide.

3. The film according to claim 1 or claim 2, wherein the filler comprises an organic filler containing at least one selected from the group consisting of liquid crystal polyester, polytetrafluoroethylene, and polyethylene.

4. The film according to any one of claims 1 to 3, wherein the filler comprises hollow particles.

5. The film according to any one of claims 1 to 4, wherein the filler comprises liquid crystal polymer particles, silica particles, or glass hollow particles.

6. The film according to claim 5, wherein the liquid crystal polymer particles include liquid crystal polymer particles whose surface has been oxidized.

7. The film according to any one of claims 1 to 6, wherein the content of the filler is 30% to 80% by volume relative to the total volume of the film.

8. A laminate comprising a film according to any one of claims 1 to 7, and a metal layer or metal wiring disposed on at least one surface of the film.

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