TW202108380A - Laminated film and method of manufacturing the laminated film do not damage low water absorption property - Google Patents

Abstract

The invention provides a laminated film having a liquid crystal polyester layer and a method of manufacturing the laminated film. The laminated film (1) of the invention can maintain the liquid crystal polyester film's inherent low water absorption and prevent the filler from falling off the filler added layer (10) because both sides (surface and rear surface) of the filler added layer (10) containing a filler-added synthetic resin are covered by the liquid crystal polyester layers (11, 12) that are not added with fillers. In addition, for example, when the laminated film (1) of the invention is used as an insulating film laminated to a metal foil in order to produce a metal foil laminated board, the filler added layer (10) can be used to enable the linear expansion coefficient of the entire laminated film (1) to close to the linear expansion coefficient of the metal foil, capable of further reducing the warpage and deformation of the metal foil laminated board.

Description

Laminated film and manufacturing method of the laminated film

The present invention relates to a laminated film having a liquid crystal polyester layer and a method for producing the laminated film.

Liquid crystal polyester film has excellent low moisture absorption, high frequency characteristics, flexibility, high gas barrier properties, thin-wall formation, etc., so it is suitable for electronic substrates such as flexible printed circuit boards, rigid printed circuit boards, and module substrates. Insulating film or surface protection film used, so the demand is increasing in recent years.

However, for example, as a circuit board on which electronic parts are mounted, in the case of using a metal foil laminate obtained by laminating the liquid crystal polyester film as an insulating film on a metal foil, the liquid crystal polyester film is generated from the electronic parts. Linear expansion occurs due to the driving heat of the metal foil, which causes the problem of deformation and warpage of the metal foil laminate.

This is because the linear expansion coefficient of insulating films made of synthetic resins is generally higher than that of metal foils, not limited to liquid crystal polyesters. As a result, a metal foil laminated board consisting only of a metal foil and an insulating film is laminated. Warping and deformation occur.

As a solution to this problem, it is conceivable to add an insulating inorganic filler to the liquid crystal polyester film for adjusting the linear expansion coefficient (linear expansion coefficient) of the liquid crystal polyester film.

In addition, Patent Document 1 discloses a liquid crystal polyester film containing silicon dioxide as a filler.

Prior art literature

Patent Document 1: Japanese Patent Publication No. 2011-201971

However, since the inorganic filler has water absorption, there are the following problems: the addition of the inorganic filler increases the water absorption (hygroscopicity) of the film, and loses the low hygroscopicity of the liquid crystal polyester. Advantages, and further increase in dielectric loss due to unevenness formed on the surface of the filler or surface segregation of the filler.

For example, for flexible printed wiring boards made of metal foil laminates made of liquid crystal polyester films containing inorganic fillers and metal foils, the inorganic fillers absorb water and cause various problems such as transmission loss, The decrease in electrical characteristics caused by the increase in insertion loss; the occurrence of corrosion of the metal foil (conductive pattern); and so on.

In addition, when the metal foil is partially etched in order to form a conductive pattern, if the insulating film of the part covered by the metal foil is exposed to the surface, there are cases in which the filler added to the insulating film of the exposed part falls off and becomes contaminants. Substances and impurities adhere to the surface of FPC (Flexible printed circuits); if necessary, cleaning and other operations are required to remove the missing filler.

In addition, insulating films made of synthetic resins, such as polyimide and liquid crystal polyester, have poor adhesion to metal foils such as copper foil. If inorganic fillers are added to the insulating film, the insulating film will be relative to the metal foil. Adhesiveness is further reduced, and if it is used for repeated bending and stretching, there is also a problem that interlayer peeling occurs immediately.

On the other hand, for the method of manufacturing liquid crystal polyester film, usually, it is extruded by the T-die method and molded into a film shape by the T-die method while being heated to a temperature higher than the melting point temperature, and then molded into a film shape by the inflation method. .

In this case, because the liquid crystal polyester has a characteristic called "liquid crystal" that has crystallinity in a molten state (liquid state), it has an instantaneous orientation from the glass transition temperature (Tg) state (amorphous state) Therefore, if a film is formed by the above-mentioned method, it will be an anisotropic film with molecular orientation in the direction of the flow of the molten resin, that is, the film transport direction (MD: machine direction) during molding. Therefore, it becomes a liquid crystal polyester film that is fragile in the TD (Transverse Direction) direction perpendicular to the MD. The liquid crystal polyester film is used as an insulating film and a metal foil laminated board formed by bonding the metal foil. Stretching in the TD direction has the problem of easily breaking in the MD direction.

In particular, if the metal foil is etched to form a conductor pattern that constitutes an electronic circuit used for mounting and connecting parts with the MD direction as the longitudinal direction, the insulating film (liquid crystal polyester film) between the conductor patterns will extend along The conductor pattern will be easily broken.

In addition, the anisotropy possessed by the liquid crystal polyester film is a cause of warpage and deformation of a metal foil laminate formed by laminating such a liquid crystal polyester film as an insulating film.

Therefore, when the insulating film of the metal foil laminate is formed of liquid crystal polyester, it is desirable not to have orientation in any of the MD and TD directions, and more preferably in the MD, TD, and Z (thickness) directions. There is no orientation in any direction.

The present invention was made to solve the above-mentioned problems. The object of the present invention is to provide a laminated film having a liquid crystal polyester layer that contains a filler in order to adjust the linear expansion rate of the entire film, and the filler does not fall off. Furthermore, it is a non-oriented laminated film without impairing low water absorption.

The technical solutions for solving the problems are described below together with the reference numerals used in the modes for implementing the invention. The reference numerals are used to clearly describe the correspondence between the description of the scope of the technical solution and the description of the mode for implementing the invention, and are of course not used to limit the interpretation of the technical scope of the present invention.

In order to achieve the above object, the laminated film 1 of the present invention is a laminated film in which a filler-free liquid crystal polyester layer 11, 12 is laminated on both sides (front and back) of a filler-added layer 10 made of a synthetic resin with a filler. (Technical Solution 1: Figure 1).

The laminated film 1 is non-oriented (technical solution 2).

In addition, the filler is suitable for silicon dioxide, talc, silicon dioxide nitride, aluminum nitride or fluorine-based powder (Technical Solution 3).

In addition, the synthetic resin is suitably liquid crystal polyester (technical solution 4), or polyimide (technical solution 5).

In addition, it is preferable that the thickness of the laminated film 1 is 3-100 μm (Technical Solution 6).

In addition, with regard to the manufacturing method of the laminated film 1 of the present invention (FIGS. 2 to 4 ), the laminated film 1 has both sides (front and back sides) of the filler-added layer 10 formed of synthetic resin with filler added. A laminated structure of liquid crystal polyester layers 11 and 12 without filler added, and the manufacturing process of the laminated film 1 includes: The first laminate manufacturing process (FIG. 2) includes a first liquid composition 31 containing a precursor of a liquid crystal polyester and a solvent, a second liquid composition 32 containing a filler and a precursor of a synthetic resin and a solvent, And the third liquid composition 33 containing the precursor of the liquid crystal polyester and the solvent is sequentially cast on the base material 40 as the engineering paper and dried, thereby manufacturing the first laminate L1, the first laminate L1 It is a laminate in which a laminate film precursor 20 is laminated on the substrate 40. The laminate film precursor 20 includes a precursor layer (first precursor layer) 21 of the liquid crystal polyester layer 11, and the filler added layer The precursor layer (second precursor layer) 22 of 10 and the precursor layer (third precursor layer) 23 of the liquid crystal polyester layer 12; In the second laminate manufacturing process (FIG. 3), after the laminate film precursor 20 is peeled from the base material 40 of the first laminate L1, the laminate film precursor 20 is transferred to a surface with On the metal base material 50 of the release layer, thereby manufacturing the second laminate L2 in which the laminated film precursor 20 is laminated on the metal base material 50; The third laminated body manufacturing process (FIG. 4), by heat-treating the second laminated body L2, to produce the third laminated body L3 in which the laminated film 1 is laminated on the metal substrate 50; and The film peeling process (FIG. 4) peels off the metal substrate 50 from the third laminate L3 (Technical Solution 7).

Preferably, the substrate 40 is a glass plate, stainless steel foil, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film or polytetrafluoroethylene sheet (technical solution 8).

The material of the metal substrate 50 is aluminum, stainless steel, iron or copper (Technical Solution 9).

The release layer is a rubber-like elastic layer (Technical Solution 10).

In addition, it is preferable that the heat treatment is performed under an inert gas atmosphere (Technical Solution 11).

According to the structure of the present invention described above, the laminated film 1 of the present invention can obtain the following remarkable effects.

The laminated film 1 of the present invention is covered with non-filler-free liquid crystal polyester layers 11 and 12 on both sides (front and back) of the filler-added layer 10 containing a synthetic resin with a filler, so it can be protected from moisture absorption by inorganic fillers. Restriction of performance, maintains the low water absorption of the original liquid crystal polyester film, and can prevent the surface segregation of the filler, and can reduce the dielectric loss caused by the surface unevenness of the filler, and can prevent the filler from falling off from the filler added layer 10 .

In addition, the surface of the filler-added layer 10 may become a rough and dull surface due to the addition of fillers. However, a laminated film of the liquid crystal polyester layers 11 and 12 without fillers is laminated on both sides of the filler-added layer 10 1. The surface can be processed into a smooth and shiny beautiful surface.

In addition, for example, in the case where the laminated film 1 of the present invention is used as an insulating film and a metal foil is laminated to produce a metal foil laminated plate, the filler addition layer 10 can make the linear expansion coefficient of the entire laminated film 1 close to that of the metal foil. The coefficient of linear expansion can further reduce the warpage and deformation of the metal foil laminate.

Furthermore, by arranging the liquid crystal polyester layer 11 (or liquid crystal polyester layer 12) without filler added on the laminated surface side of the metal foil, it is possible to prevent the laminated film 1 and the metal foil from being accompanied by the addition of fillers. The bonding strength between them is reduced.

In addition, by making the laminated film 1 of the present invention non-oriented, the anisotropy of ordinary liquid crystal polyester films can be eliminated, and mechanical strength such as tensile force with respect to the width direction can be improved. When the laminated film 1 is used as an insulating film to laminate a metal foil to produce a metal foil laminated plate, it can more effectively prevent the warping and deformation of the metal foil laminated plate caused by the anisotropy; a gap between the insulating film and the metal foil Peeling between layers; etc.

Hereinafter, the laminated film 1 of the present invention and its manufacturing method will be described with reference to the drawings.

[Overall composition]

As shown in Figure 1, the laminate film 1 of the present invention has a filler-added synthetic resin layer as a layer of filler-added layer 10 laminated on both sides of the filler-free liquid crystal polyester layers 11, 12 (in addition, for convenience See, in this specification, the reference numeral 11 is referred to as the first liquid crystal polyester layer, and the reference numeral 12 is referred to as the structure of the second liquid crystal polyester layer).

In addition, as an example, the laminated film 1 described above is suitably set to have a thickness of 3 to 100 μm.

Since the laminated film 1 is provided with the filler addition layer 10, when the laminated film 1 is used as an insulating film to be laminated on a metal foil to produce a metal foil laminated plate, the linear expansion coefficient of the entire laminated film 1 can be close to that of the metal foil. The coefficient can prevent warpage and deformation of the metal foil laminate plate due to the difference in the coefficient of linear expansion.

[Liquid Crystal Polyester Layer]

The liquid crystal polyester layers 11 and 12 have a structure containing no filler and are composed of a liquid crystal polyester described later, and therefore have ^{a moisture permeability of 0.5 g/m 2} ·24h or less.

The thickness of the liquid crystal polyester layers 11 and 12 is preferably 0.3-20 μm.

In addition, if the thickness of the liquid crystal polyester layers 11, 12 is 1 μm or less, for example, when used in a metal foil laminate, there is a possibility that the unevenness on the surface of the laminated metal foil cannot be absorbed. As a result, due to An increase in dielectric loss may occur. Therefore, from the viewpoint of maintaining the adhesion to the metal foil and the dielectric properties, the thickness of the liquid crystal polyester layers 11 and 12 is preferably 2 to 15 μm.

In addition, the thickness of the liquid crystal polyester layers 11, 12 is formed so as not to exceed the thickness of the filler-added layer 10 described later in accordance with the necessity of reducing the linear expansion coefficient of the entire laminate film 1, and is preferably formed as the filler-added layer 10 The thickness of 50% or less is more preferably a thickness of 40% or less of the filler added layer 10.

In addition, the thickness of the first liquid crystal polyester layer 11 and the thickness of the second liquid crystal polyester layer 12 may not be consistent.

Next, the liquid crystal polyester constituting the liquid crystal polyester layers 11 and 12 will be described.

This liquid crystal polyester is a polyester having the characteristics of exhibiting optical anisotropy when being melted and forming an anisotropic melt at a temperature of 450° C. or lower.

The liquid crystal polyester is preferably a liquid crystal polyester having a structural unit represented by the following formula 1 (hereinafter referred to as "formula 1 structural unit"), and a structural unit represented by the following formula 2 (hereinafter referred to as Is the "formula 2 structural unit".) and the structural unit represented by the following formula 3 (hereinafter referred to as "formula 3 structural unit".), relative to the total content of all structural units, the content of the structural unit represented by formula 1 It is 30 to 80 mol%, the content of the structural unit represented by Formula 2 is 10 to 35 mol%, and the content of the structural unit represented by Formula 3 is 10 to 35 mol%. -O-Ar ¹ -CO- (Formula 1) -CO-Ar ² -CO- (Formula 2) -X-Ar ³ -Y- (Formula 3) (In formulas 1 to 3, Ar ¹ represents benzene elongation Group or naphthylene, Ar ² represents phenylene, naphthylene or a group represented by the following formula 4, Ar ³ represents phenylene or a group represented by the following formula 4, X and Y Each independently represents O or NH. In addition, ^{the hydrogen atom bonded to the aromatic ring of Ar 1} , Ar ² and Ar ³ may be substituted with a halogen atom, an alkyl group or an aryl group) -Ar ¹¹ -Z-Ar ^12- (formula 4) (In the formula, Ar ¹¹ and Ar ¹² independently represent phenylene or naphthylene, and Z represents O, CO or SO ₂ )

The structural unit of Formula 1 is a structural unit derived from an aromatic hydroxycarboxylic acid. Examples of the aromatic hydroxycarboxylic acid include p-hydroxybenzoic acid, meta-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 3-hydroxy -2-naphthoic acid, 4-hydroxy-1-naphthoic acid, etc.

The structural unit of Formula 2 is a structural unit derived from an aromatic dicarboxylic acid. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, and 1,5 -Naphthalene dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl sulfonium-4,4'-dicarboxylic acid, diphenyl ketone-4,4'-dicarboxylic acid, etc.

The structural unit of Formula 3 is a structural unit derived from an aromatic diol, an aromatic amine having a phenolic hydroxyl group, or an aromatic diamine. Examples of the aromatic diols include hydroquinone, resorcinol, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, bis(4- Hydroxyphenyl) ether, bis(4-hydroxyphenyl)ketone, bis(4-hydroxyphenyl)sulfonate, etc.

In addition, as the aromatic amine having a phenolic hydroxyl group, 4-aminophenol (p-aminophenol), 3-aminophenol (m-aminophenol), etc., can be mentioned as the aromatic amine. Examples of amines include 1,4-phenylenediamine and 1,3-phenylenediamine.

The liquid crystal polyester used in the present invention is solvent-soluble, and the term “solvent-soluble” means that it is dissolved in a solvent at a concentration of 1% by mass or more at a temperature of 50°C. The solvent in this case is any one of suitable solvents for producing a liquid composition described later.

As such a solvent-soluble liquid crystal polyester, it is preferable to include a structural unit derived from an aromatic amine having a phenolic hydroxyl group and/or a structural unit derived from an aromatic diamine as the structural unit of Formula 3. That is, as the structural unit of Formula 3, if it contains a structural unit in which at least one of X and Y is NH (a structural unit represented by (Formula 3') (hereinafter referred to as a "formula 3'structural unit"), it will exist relative to The following suitable solvents (aprotic polar solvents) tend to have excellent solvent solubility, and are therefore preferred due to this point. It is particularly preferable that substantially all structural units of formula 3 are structural units of formula 3'. In addition, this formula 3 'The structural unit not only makes the solvent solubility of the liquid crystal polyester sufficient, but also makes the liquid crystal polyester have lower water absorption, which is also advantageous. -X-Ar ³ -NH- (formula 3') (where, Ar ³ and X have the same meaning as above.)

More preferably, the structural unit of Formula 3 contains the range of 25-33 mol% with respect to the total content of all the structural units, so that the solvent solubility can be improved. In this way, the liquid crystal polyester having the structural unit of Formula 3'as the structural unit of Formula 3 also has the following advantages: the solubility with respect to the solvent becomes better, and a liquid crystal polyester film with low water absorption can be obtained.

The content of the structural unit of Formula 1 with respect to the total content of all the structural units is preferably in the range of 30 to 80 mol%, and more preferably in the range of 35 to 50 mol%. The liquid crystal polyester containing the structural unit of Formula 1 at such a molar fraction has a tendency to be able to sufficiently maintain liquid crystallinity and to be more excellent in heat resistance. In addition, considering the availability of the aromatic hydroxycarboxylic acid from which the structural unit of Formula 1 is derived, para-hydroxybenzoic acid and/or 6-hydroxy-2-naphthoic acid are suitable as the aromatic hydroxycarboxylic acid.

The content of the structural unit of Formula 2 with respect to the total content of all structural units is preferably contained in the range of 10 to 35 mol%, and more preferably contained in the range of 25 to 33 mol%. The liquid crystal polyester containing the structural unit of Formula 2 at such a molar fraction has a tendency that the liquid crystallinity can be sufficiently maintained, and the heat resistance is more excellent. In addition, considering the availability of the aromatic dicarboxylic acid from which the structural unit of formula 2 is derived, the aromatic dicarboxylic acid is preferably derived from terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid. At least one selected from the group consisting of acids.

In addition, in the point that the obtained liquid crystal polyester can achieve higher liquid crystallinity, the molar fraction of the structural unit of formula 2 and the structural unit of formula 3 is represented by [structural unit of formula 2]/[structural unit of formula 3], preferably In the range of 0.9/1 to 1/0.9.

Next, the manufacturing method of liquid crystal polyester is demonstrated.

The liquid crystal polyester can be produced by various well-known methods. In the case of manufacturing a suitable liquid crystal polyester, that is, a liquid crystal polyester containing a structural unit of formula 1, a structural unit of formula 2, and a structural unit of formula 3, the monomers that derive these structural units are converted into ester-forming and amide-forming derivatization The method of polymerizing the material afterwards to produce a liquid crystal polyester is preferable in that it is easy to handle.

Examples of the ester-forming and amide-forming derivatives will be described.

Aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids, as ester-forming and amide-forming derivatives of monomers having a carboxyl group, include: the carboxyl group is a highly reactive group such as acyl chloride and acid anhydride , In order to promote the reaction of forming polyester and polyamide; the carboxyl group is a group that forms esters with alcohols, ethylene glycol, etc. in the manner that polyester and polyamide are formed through transesterification and amine exchange reaction.

For example, aromatic hydroxycarboxylic acids, aromatic diols, etc., as ester-forming and amide-forming derivatives of monomers having phenolic hydroxyl groups, there can be mentioned as polyester and polyamide-forming derivatives by transesterification reaction. Phenolic hydroxyl groups and carboxylic acids form esters, etc.

In addition, as aromatic diamines, as an amide-forming derivative of a monomer having an amine group, for example, a substance in which an amine group and a carboxylic acid form an amide in a manner that a polyamide is formed by an amide exchange reaction Wait.

Among them, in order to produce liquid crystal polyesters more simply, the following method of producing liquid crystal polyesters is particularly preferred: aromatic hydroxycarboxylic acids, aromatic diols, aromatic amines with phenolic hydroxyl groups, aromatic dihydric Monomers with phenolic hydroxyl and/or amine groups such as amines are acylated to make them ester-forming and amine-forming derivatives (amides). The carboxyl groups of the monomers are polymerized by transesterification and amide exchange to produce liquid crystal polyester.

The production method of such a liquid crystal polyester is described in, for example, Japanese Patent Application Publication No. 2002-220444 or Japanese Patent Application Publication No. 2002-146003.

In the acylation, the amount of fatty acid anhydride added is preferably 1 to 1.2 equivalents, and more preferably 1.05 to 1.1 equivalents based on the total of the phenolic hydroxyl group and the amino group. When the added amount of fatty acid anhydride is less than 1 equivalent, there is a tendency that the acetone and raw material monomers sublime during polymerization and easily clog the reaction system. In addition, when the amount exceeds 1.2 equivalents, the resulting liquid crystal polyester may become discolored. Significant tendency.

The acylation is preferably carried out at 130 to 180°C for 5 minutes to 10 hours, and more preferably at 140 to 160°C for 10 minutes to 3 hours.

From the viewpoint of price and handling properties, the fatty acid anhydride used for acylation is preferably acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, or a mixture of two or more selected from them, and acetic anhydride is particularly preferable.

The subsequent polymerization is preferably carried out while raising the temperature at 130 to 400°C at a rate of 0.1 to 50°C/minute, and more preferably at 150 to 350°C while raising the temperature at a rate of 0.3 to 5°C/minute.

In addition, in the polymerization, it is preferable that the acyl group of the acylate is 0.8 to 1.2 times the equivalent of the carboxyl group.

During acylation and/or polymerization, according to Le Chatelier’s law (the principle of equilibrium movement), in order to move equilibrium, it is preferable to evaporate by-produced fatty acids and unreacted fatty acid anhydrides to the outside of the system. .

In addition, the acylation and polymerization can also be carried out in the presence of a catalyst. As the catalyst, it is possible to use conventionally known materials as polyester polymerization catalysts, for example, metals such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide can be used. Salt catalyst, N,N-dimethylaminopyridine, N-methylimidazole and other organic compound catalysts.

Among these catalysts, heterocyclic compounds containing two or more nitrogen atoms such as N,N-dimethylaminopyridine and N-methylimidazole are preferably used (see Japanese Patent Laid-Open No. 2002-146003).

The catalyst is usually added together when the monomer is added, and it does not necessarily need to be removed after acylation. Without removing the catalyst, it can be transferred from acylation to polymerization as it is.

The liquid crystal polyester obtained by such polymerization can be directly used in the present invention. However, in order to further improve the characteristics of heat resistance and liquid crystallinity, it is preferable to further increase the molecular weight. Among the above-mentioned high molecular weight, the solid phase is preferably used. polymerization. A series of operations involved in the solid-phase polymerization will be described. The lower molecular weight liquid crystal polyester obtained by the polymerization is taken out, and pulverized into powder or flakes. Next, for example, under an inert gas atmosphere such as nitrogen, the pulverized liquid crystal polyester is heat-treated in a solid phase state at 20 to 350°C for 1 to 30 hours. By this operation, solid phase polymerization can be carried out. . This solid-phase polymerization may be carried out while stirring, or may be carried out in a static state without stirring. In addition, from the viewpoint of obtaining a liquid crystal polyester having a suitable flow starting temperature described later, if the suitable conditions for the solid phase polymerization are described in detail, the reaction temperature is preferably more than 210°C, and more preferably in the range of 220°C to 350°C. . The reaction time is preferably selected from 1 to 10 hours.

As the liquid crystal polyester used in the present invention, it is preferable that the flow start temperature is 250°C or higher. If the flow initiation temperature of the liquid crystal polyester is in this range, when a conductive layer (electrode) is formed on the layer containing the liquid crystal polyester, there is a possibility that the liquid crystal polyester can be formed between the layer containing the liquid crystal polyester and the conductive layer. Tendency to get higher tightness between. The flow start temperature here refers to the temperature at which the melt viscosity of the liquid crystal polyester becomes 4800 Pa·s or less under a pressure of 9.8 MPa in the evaluation of the melt viscosity by a flow tester. In addition, the flow initiation temperature as a measure of the molecular weight of the liquid crystal polyester is well known to those skilled in the art (for example, refer to Naoyi Koide "Liquid Crystal Synthesis, Molding and Application -" pages 95 to 105, CMC (シーエムシー) , Issued on June 5, 1987).

The upper limit of the flow start temperature of the liquid crystal polyester is determined by the range in which the liquid crystal polyester can be dissolved in a solvent, but is preferably 350° C. or lower. If the upper limit of the flow start temperature is in this range, in addition to the better solubility of the liquid crystal polyester with respect to the solvent, the viscosity of the liquid composition described later does not increase significantly, so there is this liquid composition The handling properties of objects tend to become better. In addition, in order to control the flow start temperature of the liquid crystal polyester in such an appropriate range, it is only necessary to appropriately optimize the polymerization conditions of the solid-phase polymerization.

[Filling Addition Layer]

The laminated film 1 of the present invention is provided with a filler-added layer 10 made of a synthetic resin to which a filler is added, so that the linear expansion coefficient of the laminated film 1 can be reduced. Thus, for example, when a metal foil laminate is manufactured using the laminate film 1 of the present invention, it is possible to approach the linear expansion coefficient of the bonded metal foil.

As the synthetic resin constituting the filler-added layer 10, various synthetic resins known as the material of the insulating film can be used, but from the viewpoint of heat resistance, it is preferable to use polyimide or liquid crystal polyester because of its low hygroscopicity. Therefore, it is preferable to use the same liquid crystal polyester as the liquid crystal polyester layers 11 and 12 described above.

The filler added to the filler addition layer 10 is added for adjusting the linear expansion coefficient of the entire laminated film 1 (mainly for the purpose of reducing the linear expansion coefficient). It is preferably an insulating inorganic filler. For example, silica or talc can be used. , Nitride silicon dioxide, aluminum nitride, etc. In addition to the above-mentioned inorganic filler, fluorine-based powder described later may also be added. Hereinafter, first, the inorganic filler will be described.

With respect to 100 parts by mass of the solid content of the liquid crystal polyester, the mixing ratio of the inorganic filler is in the range of 0.5 to 30 parts by mass. From the standpoint of maintaining the toughness of the finished film, it is preferably from 1 to 15 parts by mass, and from the viewpoint of low dielectric constant, it is more preferable 0.5-7 parts by mass.

The average particle size of the inorganic filler used is 0.001-15μm, and based on the thickness of the filler added layer 10, it is 0.05-3μm, more preferably 0.05-1μm. The particle shape may be needle-like or other shapes in addition to spherical shape. , It can also be amorphous.

In order for the resulting laminated film 1 to have a low dielectric constant, it is preferable to use a filler obtained by a combustion method, such as vapor-phase silica without moisture, as such an inorganic filler.

In addition, powders of insulating inorganic substances produced by methods other than the above, such as wet pulverization and normal pulverization, can also be used as fillers. In this case, in order to obtain fillers with low moisture content, the powders are preferably used. Heat and dry at a temperature of 100°C to 400°C or higher for 30 minutes to 12 hours.

In addition, in the present invention, in addition to the above-mentioned inorganic filler, fluorine-based powder may be added to the filler addition layer 10 as a linear expansion modifier or extender.

The fluorine-based powder refers to a powder of a composition containing fluorine in its composition, and preferably has hydrophobicity.

As the fluorine-based powder, for example, powders such as PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy alkane), FEP (perfluoroethylene propylene copolymer), and the like can be used. In addition, for example, a copolymer containing tetrafluoroethylene (component A) and a monomer (component B) having an unsaturated hydrocarbon as the main component can be used (see Fig. 6. In addition, R in the figure is preferably a hydrogen atom, a hydroxyl group, Fluorine-based powder with organic groups and alkyl groups having hydroxyl groups.

In addition, a substance having a hydroxyl group can also be used as the monomer having an unsaturated hydrocarbon as a main component. In addition, for the hydroxyl group, for example, the hydroxyl group participates in an ester bond accompanying the polymerization of the liquid crystal polyester forming the filler addition layer 10, and the hydroxyl group falls off and becomes hydrophobic.

The powder particle size of the fluorine-based powder is preferably 0.01-5 micrometers (μm), but it is not limited thereto. In addition, the average particle diameter of the fluorine-based powder is particularly preferably 0.2 to 0.25 (μm), but it is not limited to this.

In addition, the mixing ratio of the fluorine-based powder is in the range of 1 to 10 parts by mass, preferably 2 to 4 parts by mass with respect to 100 parts of the solid content of the liquid crystal polymer forming the filler addition layer 10.

As described above, the filler is adjusted and added within the range of the added amount, and the thicknesses of the liquid crystal polyester layers 11, 12 and the filler added layer 10 are adjusted to adjust the linear expansion coefficient of the entire laminate film 1, for example, The adjustment is made so as to approach the linear expansion coefficient of the metal foil bonded to the laminated film 1. In addition, for example, the difference between the linear expansion coefficient of the metal foil and the linear expansion coefficient of the laminated film 1 can also be adjusted so that the difference between the linear expansion coefficient of the metal foil and the linear expansion coefficient of the laminated film 1 becomes The linear expansion coefficient of the metal foil is 25% or less.

As an example, when the linear expansion coefficient of the copper foil as the metal foil is 19 ppm, 25% is 4.75. In this case, adjustment can be made so that the linear expansion coefficient of the laminated film 1 of the present invention Be 23.75ppm or less.

In addition, in FIG. 1, the example in which the filler addition layer 10 has a single-phase structure is shown, but the filler addition layer 10 may be further made into a multilayer structure, and the filler addition amount can be changed for each layer so that the filler addition amount There is a gradient in the thickness direction.

In this case, it is preferable that in the configuration shown in FIG. 1, an inclined structure is adopted such that the amount of filler added is reduced toward the side of the first liquid crystal polyester layer 11 and the side of the second liquid crystal polyester layer 12.

In addition, for the laminated film 1 of the present invention, for example, a resin layer, a metal layer, etc. may be further laminated on both sides of the laminated film 1 of the three-layer structure shown in FIG. 1.

[Manufacturing method of laminated film 1]

Next, referring to FIGS. 2 to 4, an example of the method for manufacturing the laminated film 1 is described. The laminated film 1 has both sides (surfaces) of the filler added layer 10 containing a synthetic resin with filler added as shown in FIG. And the back side) a laminated structure in which filler-free liquid crystal polyester layers 11 and 12 are laminated.

The manufacturing method of the laminated film 1 includes: a process of manufacturing a first laminate L1 (first process), laminating a laminate film precursor 20 on a substrate 40; a process of manufacturing a second laminate L2 (a second process), and After the laminated film precursor 20 is peeled from the base material 40 of the first laminated body L1, the laminated film precursor 20 is transferred to the surface of the metal base material 50, and is laminated on the metal base material 50 The laminated film precursor 20; the process of manufacturing the third laminated body L3 (third process), the second laminated body L2 is heat-treated, and the laminated film 1 is laminated on the metal substrate 50; and the film peeling process (Fourth process), peeling the laminated film 1 from the metal base 50 of the third laminated body L3.

In addition, the above-mentioned laminated film precursor 20 refers to a film that can be converted into the laminated film 1 of the present invention by heat treatment at a stage before the final target of the laminated film 1 in the production process of the laminated film 1 of the present invention. , Including the precursor layer (first precursor layer) 21 of the liquid crystal polyester layer 11, the precursor layer (second precursor layer) 22 of the filler addition layer 10, and the precursor layer (third precursor layer) of the liquid crystal polyester layer Precursor layer) 23.

Hereinafter, the above-mentioned first to fourth processes will be described.

[Process for manufacturing the first laminated body L1]

The process of manufacturing the first laminate L1 (the first process) is that the liquid composition 31 to 33 containing the precursor of the synthetic resin and the solvent forming the layers of the laminate film 1 is sequentially cast onto the base material as the engineering paper from the coater 40 on. More specifically, after a casting process and a drying process, the first laminate L1 having the above-mentioned laminated film precursor 20 formed on the substrate 40 is obtained, and the casting process sequentially casts the first liquid crystal polyester layer. The first liquid composition 31 containing the precursor of 11 and the solvent, the second liquid composition 32 containing the filler and the precursor containing the synthetic resin and the solvent, the precursor containing the second liquid crystal polyester layer 12, and the solvent The third liquid composition 33 of the drying process is to dry the liquid compositions 31 to 33 at a predetermined temperature for a predetermined time.

First, for the liquid compositions 31 to 33, as described above, the liquid composition contains the precursor of the synthetic resin forming each layer and the two components of the solvent. Hereinafter, the synthetic resin is the liquid crystal polyester. The liquid composition of the case will be described in detail.

For the liquid composition containing the liquid crystal polyester and a solvent, the solvent used for dissolving the liquid crystal polyester is not particularly limited as long as it can dissolve the liquid crystal polyester. For example, N,N- Dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactone, N,N-dimethylformamide, N,N-diethylformamide, N,N -Diethylacetamide, N-methylpropionamide, dimethylsulfide, γ-butyrolactone, dimethylimidazolinone, tetramethylphosphamide and ethyl cellosolve acetate, and Halogenated phenols such as fluorophenol, p-chlorophenol, and perfluorophenol. These solvents may be used alone or in combination of two or more kinds.

Among the solvents, from the viewpoint of processing, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, N,N-dimethylacetamide, Methylformamide, N,N-diethylformamide, N,N-diethylacetamide, N-methylpropionamide, dimethyl sulfide, γ-butyrolactone, dimethylimidazole An aprotic polar solvent selected from the group consisting of linone, tetramethylphosphamide, and ethyl cellosolve acetate is suitable.

The amount of the solvent used can be appropriately selected according to the type of solvent used as long as the amount of the liquid composition containing 0.1% by mass or more of liquid crystal polyester is produced. However, the amount of liquid crystal polyester is preferably 0.5 relative to 100 parts by mass of the solvent. ~50 parts by mass, more preferably 10-30 parts by mass.

If the liquid crystal polyester is less than 0.5 parts by mass, the viscosity of the liquid composition 31 tends to be too low and uniform coating may not be possible, and if it exceeds 50 parts by mass, the viscosity tends to increase.

In the liquid composition obtained in this way, the liquid crystal polyester exists in the state of a precursor, and the liquid composition is further diluted with the organic solvent to produce the liquid crystal polyester at a temperature of 25°C when the liquid crystal polyester is a 0.5 g/dl solution. The inherent viscosity is 0.1-10.

Next, a casting process for casting the liquid compositions 31 to 33 on the substrate 40 will be described.

The substrate 40 is not particularly limited as long as it is capable of peeling the laminated film precursor 20, but it is preferably a glass plate, stainless steel foil, polyethylene terephthalate film, polyethylene film, or polypropylene. Film, polymethylpentene film, polytetrafluoroethylene sheet, etc.

In addition, as a method of casting the liquid composition on the substrate 40, various known methods can be used. For example, roll coating, gravure coating, knife coating, blade coating, bar coating, and dipping can be used. Among the coating methods, spray coating methods, curtain coating methods, slit coating methods, screen printing methods, etc., the knife coating method or the slit coating method is preferred from the viewpoint of easy control and high-precision uniformity of the film thickness.

Next, a drying process for drying the liquid compositions 31 to 33 cast on the substrate 40 by the casting process to form the laminated film precursor 20 will be described.

In this drying process, if the drying temperature is too high, the precursor will start to polymerize before the heat treatment described later, and polymerization will occur, and there may be defects on the coating film surface. On the other hand, if the drying temperature is too high If it is low, it takes a long time to dry and the productivity decreases. Therefore, it is performed at a temperature of 60°C or higher and 160°C or lower, preferably at a temperature of 150°C or lower, and more preferably at a temperature of 140°C or lower.

In addition, in this drying process, it is preferable to complete the drying with the solvent contained in the liquid composition remaining, but the solvent may be completely removed.

In addition, as for the residual amount of the solvent, the residual solvent amount in the laminated film precursor 20 is preferably 18 to 2% by mass, and more preferably 15 to 5% by mass. If the residual solvent amount is 18% by mass or less, it is possible to suppress the occurrence of adhesiveness on the surface of the laminated film precursor 20, and it is possible to prevent the films from adhering to each other. In addition, if the residual solvent amount is 2% by mass or more, the film strength of the laminated film precursor 20 can be maintained, and the second laminated body L2 can be peeled from the base material 40 in the manufacturing process (second process) of the second laminated body L2 described below. When the film precursor 20 is laminated, during the heat treatment in the manufacturing process of the third laminated body L3 described later, it is possible to prevent the laminated film 1 from being damaged.

Next, if an example of a process (first process) for actually manufacturing the first laminate L1 through the above-mentioned casting process and drying process is given, as shown in FIG. 2, the formed layers are as follows: By repeating the first precursor layer to the third precursor layer forming process consisting of the casting process and the drying process three times, the first laminate in which the laminate film precursor 20 is laminated on the substrate 40 can be obtained. Body L1.

In the process of forming the first precursor layer, the filler-free liquid composition 31 containing the liquid crystal polyester precursor and the solvent is cast onto the substrate 40, and dried, and then the liquid composition 31 is dried on the substrate 40. A precursor layer (first precursor layer) 21 of the first liquid crystal polyester layer 11 containing no filler is formed thereon. In addition, the solvent used, the casting method, the temperature conditions during drying, and the like are as described above.

In the second precursor layer forming process, on the first precursor layer 21 formed on the substrate 40, a precursor containing the filler (for example, an insulating inorganic filler) and containing a synthetic resin is further cast and The liquid composition 32 of the solvent, in the present embodiment, the liquid composition 32 containing the precursor of the liquid crystal polyester and the solvent is cast and dried, thereby forming a second filler containing the filler on the first precursor layer 21 Two precursor layer 22. In addition, the solvent used in the second precursor layer formation process and the drying process, the casting method, and the temperature conditions during drying are as described above.

In addition, in the third precursor layer forming process, on the second precursor layer 22 formed by the second precursor layer forming process, a filler-free, liquid crystal polyester precursor and solvent-containing material is further cast on the second precursor layer 22 formed by the second precursor layer forming process. The liquid composition 33 is dried and the third precursor layer 23 is further formed on the second precursor layer 22. In addition, in the third precursor layer forming process, the solvent used, the casting method, and the temperature conditions during drying are as described above.

After the above-mentioned first precursor layer forming process to the third precursor layer forming process, a precursor layer (first precursor layer) 21 in which the liquid crystal polyester layer 11 is laminated on the substrate 40, and the filler added The first laminate L1 of the laminate film precursor 20 constituted by the precursor layer (second precursor layer) 22 of the layer 10 and the precursor layer (third precursor layer) 23 of the liquid crystal polyester layer. In addition, the precursor of the liquid crystal polyester contains a low molecular weight liquid crystal polyester such as an oligomer of the liquid crystal polyester.

Thereafter, as shown in Fig. 2, the first laminated body L1 is wound into a roll shape.

In addition, as another example of the process (first process) for manufacturing the first laminate L1, as shown in FIG. 5, the following method may also be used: a three-layer extrusion die and a three-layer slit coating method are used on the substrate Three layers of the above-mentioned three liquid compositions 31 to 33 are simultaneously stacked on the 40, and the above three liquid compositions 31 to 33 are cast, and the three layers are dried at the same time, thereby manufacturing the first laminate L1.

[Process for manufacturing the second laminate L2]

The first laminated body L1 in which the laminated film precursor 20 is laminated on the base material 40 is produced through the above-mentioned process of manufacturing the first laminated body L1 (first process), and the process moves to the manufacturing process of the second laminated body L2 (second process). Process), as shown in FIG. 3, as an example, the roll-shaped first laminate L1 is sent out, the laminate film precursor 20 is peeled from the substrate 40, and then the laminate film precursor 20 is transferred to the surface having The surface of the metal base material 50 of the rubber-like elastic layer. Thus, the second laminate L2 in which the metal base material 50 is laminated on the back surface of the laminate film precursor 20 is obtained. After that, the second laminated body L2 is wound into a roll shape.

At this time, the metal substrate 50 is laminated on the back surface of the laminated film precursor 20 (that is, the surface in contact with the substrate 40), but as long as the surface of the substrate 40 is smooth, the laminated film precursor 20 The back surface of the film is also smooth, and the adhesion between the laminated film precursor 20 and the metal substrate 50 can be ensured.

Here, examples of the material of the metal base 50 include aluminum, stainless steel, iron, copper, and the like. Among them, from the viewpoints of strength and corrosion resistance, stainless steel is particularly preferred.

In addition, the thickness of the metal substrate 50 is preferably in the range of 20 to 200 μm. If the thickness of the metal base material 50 is 20 μm or more, the metal base material 50 has high resistance to indentation and excellent recycling properties. If the thickness of the metal base material 50 is 200 μm or less, it becomes easy to be wound into a roll shape.

In addition, as long as the adhesion to the laminate film precursor 20 and the peelability of the laminate film 1 in the film peeling process (fourth process) described later can be ensured, any surface treatment may be performed on the surface of the metal substrate 50. . For example, in order to make the rubber-like elastic layer on the surface of the metal base 50 difficult to peel from the metal base 50, the surface of the metal base 50 may be embossed.

In addition, examples of the rubber-like elastic layer include a silicone rubber elastic layer, a fluorine rubber elastic layer, an acrylic rubber elastic layer, and the like. Among them, the silicone-based rubber elastic layer is particularly preferred. If it is a silicone-based rubber elastic layer, the adhesion to the metal substrate 50 is good, and the laminated film 1 is peeled off in the film peeling process (fourth process) described later. Sex is also good.

In addition, the thickness of the rubber-like elastic layer is preferably in the range of 5 to 100 μm. If the thickness of the rubber-like elastic layer is 5 μm or more, the difference in elastic modulus of the metal base material 50 can be sufficiently alleviated. If the thickness of the rubber-like elastic layer is 100 μm or less, it is possible to prevent chipping of the rubber-like elastic layer during the processing of the metal base material 50.

In addition, the transfer method of the laminated film precursor 20 is not particularly limited, but as shown in FIG. 3, from the viewpoint of improving productivity, it is preferable to use a pair of rollers 63, 63 to pinch the laminated film precursor 20 and Metal substrate 50.

In addition, the transfer temperature of the laminated film precursor 20 is not particularly limited, but is preferably in the range of 10 to 200°C. If the transfer temperature is 10°C or higher, the adhesion to the metal substrate 50 is good. If the transfer temperature is 200° C. or lower, the releasability of the laminated film 1 in the film peeling process (fourth process) described later will be good.

[Process for manufacturing the third laminate L3]

The second laminated body L2 in which the laminated film precursor 20 is laminated on the metal substrate 50 is produced through the above-mentioned process of manufacturing the second laminated body L2 (third process), and then moved to the manufacturing process of the third laminated body L3 ( The third process), as an example, as shown in FIG. 4, the roll-shaped second laminate L2 is sent out, and the second laminate L2 is continuously subjected to the heating furnace 65 at a predetermined temperature in a nitrogen atmosphere for a predetermined time Heat treatment. Thus, the third laminate L3 composed of the laminate film 1 substantially containing no solvent and the metal base 50 is obtained.

At this time, since the heat treatment of the second laminate L2 is performed in a nitrogen atmosphere, it is possible to prevent the deterioration of the laminate film 1 due to the acidification of the liquid crystal polyester in advance.

In addition, the heat treatment temperature of the second laminate L2 is preferably in the range of 200 to 350°C. If the heat treatment temperature is 200° C. or higher, the heat treatment increases the molecular weight of the liquid crystal polyester, and the characteristics of the laminate film 1 can be expressed from the laminate film precursor 20. If the heat treatment temperature is 350° C. or lower, thermal decomposition of the laminated film 1 (liquid crystal polyester film) can be suppressed.

On the other hand, the heat treatment time of the second laminate L2 is not particularly limited, but it is usually raised to the heat treatment temperature at a temperature increase rate of 10° C./min or less, and then maintained at the same temperature for 0 to 10 hours.

In addition, the method of heat treatment of the second laminated body L2 is not particularly limited, but a method of continuously passing through the heating furnace 65 in a roll-to-roll (a manner in which raw materials are supplied in rolls and products are completed in rolls) can be used, except In addition to this, for example, the method described in Japanese Patent Laid-Open No. 2008-207537 may be adopted.

[Film peeling process]

As described above, the third laminate L3 is manufactured, and then proceeds to the film peeling process (fourth process), and as shown in FIG. 4, the laminate film 1 is peeled from the metal substrate 50. At this time, since the rubber-like elastic layer is provided on the surface of the metal base 50, that is, on the surface on the laminated film 1 side, the laminated film 1 becomes easy to peel from the metal base 50.

Here, the peeling method of the laminated film 1 is not particularly limited, but as shown in FIG. 4, a method of continuously peeling the metal base 50 and the laminated film 1 using a pair of peeling rollers 67 is preferable.

In addition, after peeling the laminated film 1, solvent cleaning, UV treatment, corona treatment, plasma treatment, flame treatment and other methods can be used to remove contaminants (silicone, fluorine-containing substances, etc.) from the metal substrate 50 as necessary. ).

By doing so, the laminated film 1 is peeled from the metal base 50, and the manufacturing process of the laminated film 1 ends.

As described above, the laminated film 1 of the present invention includes a structure in which a coating film formed by casting and drying a liquid composition containing a liquid crystal polyester precursor and a solvent is transferred to a metal substrate 50 and then heated. The method of manufacturing is not a method in which the liquid crystal polyester flows in a certain direction in a molten state to form a film like the hot melt casting method, so the entire laminated film 1 can be made non-oriented, and the orientation direction can be eliminated. Common liquid crystal polyesters have problems such as easy cracking, and by reducing the anisotropy, it is possible to obtain the laminated film 1 that is less likely to cause warpage, deformation, and the like.

In addition, it was confirmed that the laminated film 1 produced by the above method was not only non-orientated liquid crystal polyester layers 11 and 12 without filler addition, but also that the filler-added layer 10 was non-orientated and had excellent mechanical strength in any direction.

In addition, by providing the filler addition layer 10 on the laminated film 1, the linear expansion coefficient of the entire film can be made close to, for example, the linear expansion coefficient of metal foil. In the case of bonding the laminated film 1 and the metal foil to produce a metal foil laminated plate Bottom, it can prevent warping and deformation. On the other hand, since the laminated surface with the metal foil is a liquid crystal polyester layer 11 (or liquid crystal polyester layer 12) that does not contain fillers, the laminated film will not be damaged even if fillers are added. 1 Adhesion to metal foil, and the advantageous properties of liquid crystal polyester due to its low hygroscopicity, the metal foil laminate can be made into a highly functional laminate.

1: laminated film 10: Filler added layer 11: Liquid crystal polyester layer (the first liquid crystal polyester layer) 12: Liquid crystal polyester layer (second liquid crystal polyester layer) 20: Laminated film precursor 21: First precursor layer (precursor of liquid crystal polyester layer) 22: Second precursor layer (precursor of filler addition layer) 23: The third precursor layer (precursor of the liquid crystal polyester layer) 31: The first liquid composition 32: Second liquid composition 33: The third liquid composition 40: Substrate 50: Metal substrate 63: Roll 65: heating furnace 67: Peel roller L1: First stack L2: Second stack L3: Third stack

FIG. 1 is a schematic cross-sectional view of the laminated film 1 of the present invention (a single-layer insulating film). FIG. 2 is a process diagram of the manufacturing method of the laminated film 1 of the present invention, and is a diagram showing the process of manufacturing the first laminated body L1. Fig. 3 is a diagram showing a process of manufacturing a second laminated body L2 from the first laminated body L1 of Fig. 2. 4 is a diagram showing a process of manufacturing a third laminate L3 from the second laminate L2 of FIG. 3 and peeling off the laminate film 1 (engineering paper). FIG. 5 is a diagram showing a manufacturing process of another embodiment of the first laminated body L1. Fig. 6 is a diagram showing a chemical formula of an example of a fluorine-based powder.

1: laminated film

10: Filler added layer

11: Liquid crystal polyester layer (first liquid crystal polyester layer)

12: Liquid crystal polyester layer (second liquid crystal polyester layer)

Claims (11)

A laminated film characterized in that a liquid crystal polyester layer with no filler added is laminated on both sides of a filler added layer containing a synthetic resin with a filler added. The laminated film according to claim 1, wherein the laminated film is non-oriented. The laminated film according to claim 1 or 2, wherein the filler is silicon dioxide, talc, silicon dioxide nitride, aluminum nitride, or fluorine-based powder. The laminated film according to any one of claims 1 to 3, wherein the synthetic resin is a liquid crystal polyester. The laminated film according to any one of claims 1 to 3, wherein the synthetic resin is polyimide. The laminated film according to any one of claims 1 to 5, wherein the thickness is 3 to 100 μm. A method for producing a laminated film, characterized in that the laminated film has a laminated structure in which a filler-free liquid crystal polyester layer is laminated on both sides of a filler-added layer containing a synthetic resin with a filler. The manufacturing method includes: a first laminate manufacturing process, combining a first liquid composition containing a liquid crystal polyester precursor and a solvent, a filler containing a synthetic resin precursor and a solvent containing a second liquid composition, and The third liquid composition of the precursor of the liquid crystal polyester and the solvent is sequentially cast on a substrate and dried, thereby manufacturing a first laminate, which is laminated on the substrate containing all The precursor layer of the liquid crystal polyester layer, the precursor layer of the filler added layer, and the laminate film precursor of the precursor layer of the liquid crystal polyester layer; the second laminate manufacturing process, the laminate film precursor is removed from the After the substrate of the first laminate is peeled off, the laminate film precursor is transferred to a metal substrate having a release layer on the surface, thereby manufacturing a second laminate. The metal substrate is laminated with a laminated film precursor; the third laminated body manufacturing process, by heat-treating the second laminated body to produce a third laminated body, the third laminated body is laminated on the metal substrate There are laminated films; and a film peeling process for peeling the metal substrate from the third laminate. The method of manufacturing a laminated film according to claim 7, wherein the substrate is a glass plate, stainless steel foil, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene Membrane, or PTFE sheet. The method for producing a laminated film according to claim 7 or 8, wherein the material of the metal substrate is aluminum, stainless steel, iron, or copper. The method for producing a laminated film according to any one of claims 7 to 9, wherein the release layer is a rubber-like elastic layer. The method for producing a laminated film according to any one of claims 7 to 10, wherein the heat treatment is performed in an inert gas atmosphere.

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