TW201840648A - Polyimide film - Google Patents

Abstract

Provided is a polyimide film that can be utilized as a flexible printed circuit board, etc. The polyimide film has a dielectric tangent of 0.007 or lower, a water absorption rate of 0.8% or lower, and a linear expansion coefficient at 50-200 DEG C of 30 ppm/DEG C or lower.

Description

Polyimine film

The present invention relates to a polyimide film or the like.

In motor products, small or thinner, it is necessary to use a flexible printed circuit (FPC). In recent years, in addition to these, the speed of the wireless Internet or communication equipment is increasing, and the operation is performed at a high frequency, and a circuit board capable of achieving a high transmission speed is required. As a specific example, it is exemplified as an antenna portion for a smart phone or a tablet terminal, and these are thinner and thinner, so they are as thin as possible and are listed as required characteristics.

It is known that the transmission speed of a semiconductor element is mainly limited by the delay between the metal lines of the transport signal. In order to reduce the delay of signal transmission, the insulating layer with a low dielectric constant can be disposed between the lines, thereby reducing the capacitive coupling between the lines, thereby improving the operation speed and reducing the noise disturbance. The insulating layer can block the flow of current, and if the dielectric constant is low, the transmission speed is increased, and if the dielectric loss tangent is low, the transmission loss can be reduced. That is, the thermal expansion coefficient (CTE, linear expansion coefficient) of the high-frequency circuit substrate is low, and the dielectric constant (Dk) and the dielectric loss tangent (Tan δ) must be stably lowered. Moreover, in the manufacturing process, since the roller is conveyed by the roll, high strength and high elasticity are required. Further, in the solder step at the time of formation of the circuit board, high heat resistance is required.

As such an insulating layer, a laminated film using a fluororesin film and a polyimide film was investigated. For example, Patent Document 1 discloses a laminated film having a fluorine-based resin on both sides of a polyimide film or a single-layer layer.

Further, Patent Document 2 discloses that a double-sided or single-area layer having an aromatic polyimide film having a main acid skeleton derived from biphenyltetracarboxylic acid which is subjected to discharge treatment on both surfaces is provided in pairs A laminated film of a fluororesin film having a discharge treatment is applied to the surface. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. Hei 8-276547 (Patent Document 2) Japanese Patent Publication No. Hei 5-59828

[The problem that the invention wants to solve]

It is an object of the present invention to provide a novel polyimide film. [Technical means to solve the problem]

As described above, in the insulating layer such as FPC, a laminated film of a fluororesin film and a polyimide film is used. It is considered that the combination of the two resin films is considered in consideration of the balance of various physical properties. For example, the polyimide film has insufficient communication speed, and on the other hand, the fluororesin film has insufficient strength or dimensional stability, but it is assumed that the two resins can be reduced by combining the two resins. Disadvantages.

However, according to the study by the inventors of the present invention, it is understood that even such a laminated film is improved, for example, when the dimensional accuracy is insufficient or the selection of the via hole is narrowed (for example, UV (ultraviolet cannot be used). , ultraviolet light, laser, etc.).

Therefore, the inventors of the present invention have studied whether or not a film which can be used for FPC or the like can be formed by a single layer film of polyimine without using a resin which is laminated. However, the monolayer film of polyimine does not have sufficient low dielectric properties or low water absorption properties, or the dimensional accuracy is insufficient, and the single layer film of polyimine which can sufficiently satisfy the properties can be explored. Extremely difficult.

Under the above circumstances, the inventors of the present invention have repeatedly tried hard to study, and found that even by selecting a raw material of polyimine or a gel film as a precursor of a film, etc., even a single polyimide The layer film can also sufficiently satisfy the characteristics as described above, and further studies are carried out to complete the present invention.

That is, the present invention relates to the following polyimide film and the like. [1] A polyimide film having a dielectric loss tangent of 0.007 or less, a water absorption ratio of 0.8% or less, and a linear expansion coefficient of 50 ppm/° C. or less at 50 to 200 °C. [2] The polyimine film according to [1], which has a relative dielectric constant of 3.3 or less. [3] The polyimine film according to any one of [1] to [2] wherein the polymer component of the polyimine which constitutes the polyimide film is selected from the group consisting of diamine components (A) and At least one of the carboxylic acid component (B) contains fluorine. [4] The polyimine film according to [3], wherein the diamine component (A) contains 60% by mole or more of the fluorine-containing diamine component (A1). [5] The polyimine film according to [3] or [4] wherein the diamine component (A) contains 65 mol% or more of 2,2'-bis(trifluoromethyl)benzidine. [6] The polyimine film according to any one of [3] to [5] wherein the diamine component (A) comprises a fluorine-containing diamine component (A1) and a fluorine-free diamine component (A2). ). [7] The polyimine film according to any one of [3] to [6] wherein the tetracarboxylic acid component (B) comprises 3,3',4,4'-biphenyltetracarboxylic dianhydride 60 More than Mole. [8] The polyimide film according to any one of [1] to [7], which is used for a base film and/or a cover layer of a copper foil laminate. [9] A method for producing a polyimine film according to any one of [1] to [8], which is obtained by a chemical ring closure method, and is produced using the gel film. The polyimine film described in any one of [1] to [8]. [10] A metal laminate comprising the polyimine film according to any one of [1] to [8]. [11] The metal laminate according to [10], which is a copper foil laminate having a polyimide film as a base film. [12] The metal laminate according to [10] or [11], wherein the polyimide film constitutes a cover layer of the protective metal layer. [Effects of the Invention]

In the present invention, a novel polyimine film can be provided. Such a polyimide film has characteristics such as low dielectric constant or low water absorption (even low permeability of water vapor or gas). Therefore, for example, it can be preferably used as a film for FPC (base film, cover layer, etc.), and the like, and can be preferably used for high-frequency corresponding substrate applications. Further, the polyiminoimine film of the present invention has a relatively low CTE (linear expansion coefficient) in many cases. Therefore, even when laminated on a metal layer, dimensional stability is high, which is suitable for FPC use and the like. It is not easy to have both a low dielectric constant or a low water absorption, and a high dimensional accuracy. These can be achieved at the same time, and it is possible to achieve both accidents in a single layer of polyimide film, and the usefulness of the present invention is extremely high. high. Further, since the polyimide film of the present invention does not require a laminate of a resin film, it is possible to easily cope with film formation.

[Polyimide film] The polyimide film of the present invention sufficiently satisfies a specific range in dielectric properties or water absorption. In addition, the polyimine film of the present invention may satisfy at least one of the dielectric properties of the specific range and the water absorption rate of a specific range, and may sufficiently satisfy either of them.

The dielectric loss tangent of the polyimine film of the present invention may be selected from the range of 0.015 or less (for example, 0.012 or less), and may be, for example, 0.01 or less (for example, 0.0095 or less), preferably 0.009 or less (for example, 0.0085 or less). Further, it is preferably 0.008 or less (for example, 0.0075 or less), particularly preferably 0.007 or less (for example, 0.0065 or less), particularly preferably 0.006 or less (for example, 0.0058 or less), and may be 0.0055 or less and 0.0050 or less. The lower limit of the dielectric loss tangent is not particularly limited, and may be, for example, 0.001, 0.0015, 0.002, 0.0025, 0.0030, 0.0035, or the like.

The relative dielectric constant of the polyimide film may be selected from the range of 3.5 or less (for example, 3.4 or less), for example, may be less than 3.4 (for example, 3.37 or less), preferably 3.35 or less (for example, 3.32 or less), and further It is preferably 3.3 or less (for example, 3.25 or less), and may be 3.2 or less (for example, 3.15 or less), 3.1 or less (for example, 3.05 or less), 3.0 or less (for example, 2.95 or less), or the like. The lower limit of the relative dielectric constant is not particularly limited, and may be, for example, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, or the like.

Further, the method of measuring the dielectric loss tangent and the dielectric constant is not particularly limited, and may be based on a conventionally known method. The measurement frequency of the dielectric loss tangent and the dielectric constant can be, for example, 2.54 GHz, 5.8 GHz, or the like.

The polyimide film which satisfies the dielectric properties of a specific range sufficiently satisfies the above range in at least one of the dielectric loss tangent and the relative dielectric constant in the dielectric characteristics. It is preferable that the above range is sufficiently satisfied at least in the dielectric loss tangent, and it is more preferable that the above range is sufficiently satisfied in both the dielectric loss tangent and the relative dielectric constant.

The water absorption of the polyimide film may be selected from the range of 2% or less (for example, 1.5% or less), for example, 1.2% or less (for example, 1.1% or less), preferably 1.0% or less (for example, 0.95%). The following) is more preferably 0.9% or less (for example, 0.85% or less), particularly preferably 0.8% or less (for example, 0.75% or less), particularly preferably 0.7% or less (for example, 0.65% or less), or 0.6%. The following (for example, 0.55% or less), 0.5% or less (for example, 0.45% or less), 0.4% or less (for example, 0.35% or less), or the like. The lower limit of the water absorption rate is not particularly limited, and may be, for example, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10% or the like.

In addition, the measuring method of the water absorption rate is not particularly limited, and for example, it can be measured according to JIS K 7209 or the like, and the water absorption rate can also be measured by the method described in the following examples.

The polyimide film can have a specific coefficient of linear expansion. The linear expansion coefficient (absolute value of the coefficient of linear expansion) of the polyimide film can be selected from the range of 40 ppm/° C. or less (for example, 37 ppm/° C. or less), for example, 35 ppm/° C. or less (for example, 33). Ppm/°C or less), preferably 32 ppm/° C. or less (for example, 31 ppm/° C. or less), further preferably 30 ppm/° C. or less (for example, 28 ppm/° C. or less), particularly 25 ppm/° C. or less. (for example, 22 ppm/°C or less), preferably 20 ppm/°C or less (for example, 19 ppm/°C or less), or 18 ppm/°C or less. Further, the lower limit of the coefficient of linear expansion (or its absolute value) is not particularly limited and may be selected according to the use, etc., and may be 0 ppm/° C., 2 ppm/° C., 3 ppm/° C., 5 ppm/° C. 8 ppm/°C, 10 ppm/°C, etc. In particular, in the case where the metal laminate is formed as described below, for example, the linear expansion coefficient of the polyimide film may be close to the linear expansion coefficient of the metal layer or the metal constituting the metal layer, which may be the same or smaller. For example, when the metal layer or the metal constituting the metal layer is copper, the linear expansion coefficient of the polyimide film may be 0 to 25 ppm/° C., 5 to 22 ppm/° C., 8 to 20 ppm/° C., 10 ~18 ppm/°C, etc. Further, the coefficient of linear expansion may be a coefficient of linear expansion within a specific temperature range (for example, 50 to 200 ° C).

The method for measuring the linear expansion coefficient is not particularly limited, and for example, it can be measured by the method described in the following examples.

The glass transition temperature of the polyimide film (or the polyimide which constitutes the polyimide film) is not particularly limited, and may be, for example, 150 ° C or higher (for example, 180 to 450 ° C), preferably 200 ° C or higher ( For example, it is 230 to 400 ° C), and more preferably 250 ° C or higher (for example, 260 to 380 ° C). The thickness of the polyimide film is not particularly limited and may be appropriately selected depending on the use and the like. For example, the polyimide film may have a thickness of 1 to 200 μm (for example, 2 to 150 μm), preferably 3 to 100 μm (for example, 4 to 90 μm), and more preferably 5 to 80 μm (for example, , 7 to 60 μm), or 50 μm or less, 40 μm or less, 30 μm or less. Since the polyimide film of the present invention can sufficiently satisfy the required performance even if it is not laminated with the fluororesin film, it can easily be made thinner.

Further, the polyimide film may be a laminate of a plurality of polyimide membranes, and may generally be a single polyimide film.

[Method for Producing Polyimine and Polyimine Film] Polyimine film (or polyimine or polylysine constituting a polyimide film) is a diamine component and a tetracarboxylic acid component As a polymerization component. Further, the polymerization component may contain other polymerization components as long as the diamine component and the tetracarboxylic acid component are the main components.

Specifically, in the production of a polyimine (or a polyimide film), first, a diamine component (diamine component (A)) and a tetracarboxylic acid component (tetracarboxylic acid component (B)) are used. The polyglycine (polyimine precursor) solution is obtained by polymerization in an organic solvent.

Further, polylysine is supplied to the cyclization reaction, and in the present invention, it is preferably cyclized by a chemical ring closure method as described below. Therefore, polylysine (diamine component (A) and tetracarboxylic acid component (B)) is preferably a component which can be subjected to a chemical ring closure method (chemical ring closure) (or can be efficiently and efficiently by a chemical ring closure method) The component of cyclization).

The diamine component (A) usually contains at least an aromatic diamine component. Further, the tetracarboxylic acid component (B) usually contains an aromatic tetracarboxylic acid component.

Polyimine may generally contain fluorine. The fluorine-containing polyimide (polyimine film) is not particularly limited as long as it is a polymerization component, and at least a fluorine-containing polymerization component can be used as a polymerization component.

Specifically, at least one component selected from the group consisting of the diamine component (A) and the tetracarboxylic acid component (B) (especially at least the diamine component (A)) may contain fluorine. In addition, the fluorine-containing form is not particularly limited, and examples thereof include a state in which a hydrogen atom constituting a diamine component or a tetracarboxylic acid component is substituted with a fluorine atom. For example, as the diamine component or the tetracarboxylic acid component, a perfluoroalkane skeleton having a skeleton substituted with a fluorine atom (for example, a fluorinated alkane skeleton [for example, a trifluoromethane skeleton (or trifluoromethyl group) (or a perfluoroalkyl group or the like, a component of a hydrocarbon skeleton such as a fluorinated aromatic hydrocarbon skeleton (for example, a fluorobenzene skeleton).

The specific diamine component (A) can be roughly classified into, for example, a fluorine-free diamine component (A2) and a fluorine-containing diamine component (A1).

Examples of the fluorine-free diamine component (A2) include diamino aromatic hydrocarbons (for example, p-phenylenediamine, m-phenylenediamine, 1,5-diaminonaphthalene, etc.), and diaminodiaryl groups. [or bis(aminoaryl), such as benzidine, 3,3'-dimethoxybenzidine], bis(aminoalkyl)arene (eg, p-xylylenediamine, etc.), Aminoaryl)ethers (eg, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, etc.), bis(aminoaryl)alkanes (eg, 4, 4' -diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane), bis(aminoaryl)anthracene (eg, 4,4'-diamine) Diphenyl hydrazine), bis(aminoaryl)arene [eg, 1,4-bis(3-methyl-5-aminophenyl)benzene, etc.], bis(aminoaryloxy) arene [ For example, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene], bis[(aminoaryloxy)aryl]alkane {for example A non-fluorine-containing aromatic diamine component such as a 2,2-bis[4-(4-aminophenoxy)phenyl]propane or the like, or a guanamine-forming derivative thereof.

The fluorine-free diamine component (A2) may be used singly or in combination of two or more.

Among these, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene, 1,4-double are preferred. (4-Aminophenoxy)benzene and the like. Therefore, the diamine component (A2) may contain a compound selected from 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene, And at least one of 1,4-bis(4-aminophenoxy)benzene.

The fluorine-containing diamine component (A1) may, for example, be a compound in which hydrogen (atoms) constituting the fluorine-free diamine component (A2) is substituted with fluorine (atoms), for example, a fluorine-containing diaminodiaryl group. {or a fluorine-containing bis(aminoaryl) group such as a fluoroalkyl benzidine [for example, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-bis(trifluoromethyl) linkage Fluorine C _1-10 alkylbenzidine such as aniline, preferably perfluoro C _1-4 alkylbenzidine, etc., etc., fluorine-containing bis(aminoaryl)alkane {for example, bis(aminophenyl) a fluorinated alkane [for example, a bis(aminophenyl)fluoro C _1-10 alkane such as 2,2-bis(4-aminophenyl)hexafluoropropane, preferably a di(aminophenyl)perfluorocarbon. A fluorine-containing aromatic diamine component such as a C _1-4 alkane or the like, or a guanamine-forming derivative thereof.

Among these, a fluoroalkylbenzidine [especially 2,2'-bis(trifluoromethyl)benzidine] is preferred.

The fluorine-containing diamine component (A1) may be used singly or in combination of two or more.

The diamine component (A) may be used singly or in combination of two or more.

In particular, the diamine component (A) may contain at least a fluorine-containing diamine component (A1).

When the diamine component (A) contains the fluorine-containing diamine component (A1), the ratio of the fluorine-containing diamine component (A1) may be, for example, 20 mol% or more of the diamine component (A) (for example, 25 to 100 mol%), preferably 30 mol% or more (for example, 40 mol% or more), more preferably 50 mol% or more (for example, 55 mol% or more), especially 60 mol. % or more (for example, 65 mol% or more) may be 70 mol% or more (for example, 75 mol% or more), 80 mol% or more (for example, 85 mol% or more), and 90 mol%. The above (for example, 95% or more) or the like.

Further, the fluorine-containing diamine component (A1) and the fluorine-free diamine component (A2) can be preferably combined.

In this case, the ratio of the fluorine-containing diamine component (A1) to the fluorine-free diamine component (A2) may be, for example, a fluorine-containing diamine component (A1) / a fluorine-free diamine component (A2). (Mohr ratio) = 99.9/0.1 to 1/99 (for example, 99.5/0.5 to 5/95), preferably 99/1 to 10/90 (for example, 98/2 to 20/80), and further Preferably, it is 97/3 to 30/70 (for example, 96/4 to 35/65), especially 95/5 to 40/60 (for example, 93/7 to 45/50), and particularly preferably 92/8 to 50. The range of /50 (for example, 90/10 to 55/45) is usually 99/1 to 60/40 (for example, 95/5 to 65/35).

The specific tetracarboxylic acid component (B) can be roughly classified into, for example, a fluorine-free tetracarboxylic acid component (B2) and a fluorine-containing tetracarboxylic acid component (B1).

The fluorine-free tetracarboxylic acid component (B2) may, for example, be a fluorine-free tetracarboxylic acid and a guanamine-forming derivative thereof, for example, an aromatic hydrocarbon tetracarboxylic acid component [for example, pyromellitic acid, 2, 3, 6 , 7-naphthalenetetracarboxylic acid, pyridine-2,3,5,6-tetracarboxylic acid, anhydrides thereof (such as pyromellitic dianhydride), etc., bis(dicarboxyaryl)ether component (for example, 4,4'-oxydiphthalic acid, 4,4'-oxydiphthalic anhydride, etc.), diaryltetracarboxylic acid component [for example, 3,3',4,4'-biphenyl four Carboxylic acid, 2,3',3,4'-biphenyltetracarboxylic acid, anhydrides thereof (3,3',4,4'-biphenyltetracarboxylic dianhydride, etc.), etc., diaryl ketone a tetracarboxylic acid component (for example, 3,3',4,4'-benzophenonetetracarboxylic acid and its anhydride, etc.), bis[(dicarboxyphenoxy)phenyl]alkane component {for example, 5, 5 '-[1-Methyl-1,1-ethanediylbis(1,4-phenylene)dioxy]bis(isobenzofuran-1,3-dione), etc.

The fluorine-free tetracarboxylic acid component (B2) may be used singly or in combination of two or more.

The fluorine-containing tetracarboxylic acid component (B1) may, for example, be a compound in which hydrogen (atoms) which do not contain a fluorine-containing tetracarboxylic acid component are substituted with fluorine (atoms), for example, a fluorine-containing bis(dicarboxyaryl)alkane. {For example, bis(dicarboxyphenyl)fluoroalkane [for example, bis(dicarboxyphenyl)fluoro C _1-10 alkane such as 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, It is preferably bis(dicarboxyphenyl)perfluoro C _1-4 alkane], etc.

The fluorine-containing tetracarboxylic acid component (B1) may be used singly or in combination of two or more.

The tetracarboxylic acid component (B) may be used singly or in combination of two or more.

Among these, a 3,3',4,4'-biphenyltetracarboxylic acid component (an acid anhydride or the like) can be preferably used. Therefore, the tetracarboxylic acid component (B) may contain at least a 3,3',4,4'-biphenyltetracarboxylic acid component. By using the 3,3',4,4'-biphenyltetracarboxylic acid component, the following chemical ring closure method can be easily applied, and the desired properties (dielectric properties, water absorption, CTE, etc.) can be easily achieved.

In the case where the tetracarboxylic acid component (B) contains a 3,3',4,4'-biphenyltetracarboxylic acid component, the ratio of the 3,3',4,4'-biphenyltetracarboxylic acid component may be, for example, 20 mol% or more (for example, 25 to 100 mol%) of the tetracarboxylic acid component (B), preferably 30 mol% or more (for example, 40 mol% or more), and further preferably 50 mol%. The above (for example, 55 mol% or more), especially 60 mol% or more (for example, 65 mol% or more), or 70 mol% or more (for example, 75 mol% or more), 80 mol. % or more (for example, 85 mol% or more), 90 mol% or more (for example, 95 mol% or more), or the like.

Further, the tetracarboxylic acid component (B) may preferably contain a fluorine-containing tetracarboxylic acid component (B1), and in this case, the fluorine-containing tetracarboxylic acid component (B1) and the fluorine-free fourth component may also be used. The carboxylic acid component (B2) is combined.

When the tetracarboxylic acid component (B) contains the fluorine-containing tetracarboxylic acid component (B1), the ratio of the fluorine-containing tetracarboxylic acid component (B1) may be, for example, 1 mol% of the tetracarboxylic acid component (B). The above (for example, 1 to 100 mol%) is preferably 2 mol% or more (for example, 3 to 80 mol%), and more preferably 5 mol% or more (for example, 6 to 50 mol%). In particular, it is 10 mol% or more (for example, 10 to 40 mol% or more), and usually it may be 1 to 50 mol% (for example, 3 to 40 mol%, and 5 to 35 mol%).

Specific examples of the organic solvent used for the formation of the polyaminic acid solution include an anthraquinone solvent such as dimethyl hydrazine or diethyl hydrazine, N,N-dimethylformamide, and N. , a methylamine solvent such as N-diethylformamide, an acetamide solvent such as N,N-dimethylacetamide or N,N-diethylacetamide, or N-methyl-2. - Pyrrolidone-based solvent such as pyrrolidone or N-vinyl-2-pyrrolidone, phenol, o-, m- or phenolic solvent such as p-cresol, xylenol, halogenated phenol or catechol or An aprotic polar solvent such as methylphosphonamide or γ-butyrolactone is preferably used singly or in combination of two or more kinds, and an aromatic hydrocarbon such as xylene or toluene may also be used.

The polymerization method can be carried out by any known method. For example, (1) first, the entire amount of the diamine component is placed in a solvent, and thereafter, in a manner equivalent to the total amount of the diamine component (equal molar amount). A method of adding a tetracarboxylic acid component and polymerizing. (2) First, the entire amount of the tetracarboxylic acid component is placed in a solvent, and thereafter, a method in which a diamine component is added in an amount equivalent to the tetracarboxylic acid component and polymerized is carried out. (3) After the diamine component (a1) is placed in a solvent, the reaction is carried out at a ratio of 95 to 105 mol% based on the reaction component and the tetracarboxylic acid component (b1). After the time, the other diamine component (a2) is added, and then the other tetracarboxylic acid component (b2) is added in such a manner that the entire diamine component and the entire tetracarboxylic acid component are substantially equivalent. . (4) After the tetracarboxylic acid component (b1) of one of the components is placed in a solvent, the reaction is carried out at a ratio of 95 to 105 mol% based on the diamine component (a1) of the reaction component. After the time, the other tetracarboxylic acid component (b2) is added, and then the other diamine component and the total tetracarboxylic acid component are added in an amount equivalent to each other, and the other diamine component (a2) is added and polymerized. . (5) The polyamine reagent solution (A) is adjusted by reacting one of the diamine component and the tetracarboxylic acid component in excess of any one of the components in the solvent, and the other diamine component is added to the other solvent. The polyamic acid solution (B) is adjusted by reacting with the tetracarboxylic acid component in such a manner that any one of the components is excessive. The polyamic acid solutions (A) and (B) thus obtained are mixed and the polymerization is terminated. The polymerization method is not limited to these, and other known methods can also be used.

The polyaminic acid solution usually contains about 5 to 40% by weight of a solid content component, preferably about 10 to 30% by weight of a solid content component. Further, the viscosity of the polyaminic acid solution is usually about 10 to 2000 Pa·s in terms of a measurement value obtained by a Brookfield viscosity meter, and is preferably about 100 to 1000 Pa·s in order to achieve stable liquid supply. Further, the polylysine in the organic solvent solution may be partially imidized.

Next, a method of producing a polyimide film will be described. The film formation (manufacture) of the polyimide film can be obtained, for example, by subjecting a polyaminic acid solution to a cyclization reaction to obtain a gel film (converting a polyaminic acid or a polyaminic acid solution into a gelation) Step (1) of the film; the obtained gel film is subjected to a drying (and desolvation) treatment, and a heat treatment step (2) is carried out. Further, drying and hydrazine imidization are carried out by drying and heat treatment.

In the step (1), the method of subjecting the polyproline solution to a cyclization reaction is not particularly limited, and specific examples thereof include (i) casting a polyglycine solution into a film form for thermal dehydration. A method of obtaining a gel film by cyclization (thermal closed-loop method), or (ii) mixing a catalyst (cyclization catalyst) and a dehydrating agent (converting agent) in a polyaminic acid solution to carry out chemical decyclization A gel film, a method of obtaining a gel film by heating (chemical ring closure method), etc., and the latter method (chemical ring closure method) is particularly preferable.

According to the chemical ring closure method (further, the specific diamine component and/or tetracarboxylic acid component as described above is selected, and the chemical ring closure method is selected), it is unexpectedly easy to efficiently obtain the desired polyimide film of the present invention. Physical properties, properties (dielectric properties, water absorption, CTE, etc.). Further, from the viewpoint of mass production, a chemical ring closure method is also preferred.

Further, the polyamic acid solution may contain a gelation retarder or the like. The gelation retarder is not particularly limited, and acetonitrile or the like can be used.

Examples of the cyclization catalyst include amines such as aliphatic tertiary amines (trimethylamine, triethylamine, etc.), aromatic tertiary amines (dimethylaniline, etc.), and heterocyclic tertiary amines. (for example, isoquinoline, pyridine, β-methylpyridine, etc.) and the like. These may be used alone or in combination of two or more. Among these, a heterocyclic tertiary amine such as β-picoline is preferred.

Examples of the dehydrating agent include acid anhydrides such as aliphatic carboxylic anhydrides (for example, acetic anhydride, propionic anhydride, butyric anhydride, etc.), aromatic carboxylic anhydrides (for example, benzoic anhydride, etc.), and the like. These may be used alone or in combination of two or more. Among these, acetic anhydride and/or benzoic anhydride are preferred, and acetic anhydride is particularly preferred.

The amount of the cyclized catalyst and the dehydrating agent to be used is not particularly limited, and may be 1 mol per mol of the amide group (or carboxyl group) of polyamic acid (or polyamic acid), respectively. For example, it is about 1 mole or more (for example, 1.5 to 10 moles).

The gel film can usually be cast (coated) on a support and partially dried and hardened by a polyaminic acid solution (especially a polyamic acid solution mixed with a cyclized catalyst and a conversion agent). Obtained by imidization).

More specifically, it can be obtained by casting a poly-proline solution from a nozzle attached to a slit onto a support to form a film, by heating from a support, from hot air or electricity. A heat source such as a heater is heated to cause a ring closure reaction, and a volatile component such as a free organic solvent is dried to form a gel film, which is then peeled off from the support.

Here, the gel film must be self-supporting for peeling, and the gel film obtained by the chemical ring closure method is generally different from the gel film obtained by the thermal ring closure method. That is, in the chemical ring closure method, since it can be gelled (converted) by a catalyst, a self-supporting gel film (soft or moist gel film) containing a large amount of solvent can be obtained, and, on the other hand, In the thermal closed-loop method, a large amount of heat treatment is required in order to achieve gelation (self-supporting), and as a result, a relatively hard (less residual solvent) gel film is obtained.

In the present invention, it is possible to efficiently form a desired property (low dielectric loss tangent, low dielectric constant, low water absorption, low CTE, etc.) by using a gel film via a chemical ring closure method. Polyimine film.

The support is not particularly limited, and examples thereof include a drum made of a metal (for example, stainless steel), an endless belt, and the like. The temperature of the support is not particularly limited and may be, for example, 30 to 200 ° C, preferably 40 to 150 ° C, and more preferably 50 to 120 ° C.

Further, the temperature of the support can be controlled by (i) a heat medium of liquid or gas, (ii) radiant heat of an electric heater or the like.

In the step (2), the gel film is dried (desolvation) and then heat-treated. In general, the step (2) may include a step of drying the both ends of the gel film in the width direction and passing it through a heating furnace (such as a tenter heating furnace), followed by heat treatment.

Specifically, the gel film which is peeled off from the support is not particularly limited, and generally, the transfer speed can be extended in the transport direction while the transfer speed is restricted by the rotating roller. The extension in the transport direction can be carried out at a specific temperature (for example, a temperature of 140 ° C or less). The stretching ratio (MDX) is usually 1.05 to 1.9 times, preferably 1.1 to 1.6 times, more preferably 1.1 to 1.5 times (for example, 1.15 to 1.4 times).

Drying can be, for example, at a drying temperature of 210 ° C or higher (for example, 213 to 500 ° C), preferably 215 ° C or higher (for example, 218 to 400 ° C), and more preferably 220 ° C or higher (for example, 220 to 300 ° C). get on.

Further, drying can be carried out while suppressing drying unevenness (difference) in the film width direction. For example, the drying temperature unevenness in the film width direction may be, for example, less than 25 ° C (for example, 0 to 24 ° C), preferably 22 ° C or lower (for example, 1 to 21 ° C), and more preferably 20 ° C or lower (for example, , 2 to 19 ° C), particularly preferably 18 ° C or less (for example, 3 to 18 ° C).

Further, the drying temperature unevenness may be, for example, taken at a specific interval (for example, 200 mm) along the film width direction, and the difference (amplitude) between the maximum value and the minimum value of the measured drying temperature is determined as the drying temperature. All.

The gel film (especially the gel film extending in the transport direction) is heat-treated after drying. The heat treatment temperature is not particularly limited, and may be, for example, 200 ° C or higher (for example, 250 to 600 ° C), preferably 300 ° C or higher, and more preferably 350 ° C or higher.

Moreover, it can extend in the width direction after drying. The extension in the width direction can be carried out together with the heat treatment.

In the extension in the width direction, the stretching ratio (TDX) may be, for example, 1.05 to 1.9 times, preferably 1.1 to 1.6 times, more preferably 1.1 to 1.5 times (for example, 1.15 to 1.4 times).

Further, with such extension, it is easy to further reduce (or easily adjust) the dielectric loss tangent, relative dielectric constant, CTE, water absorption, and the like.

The polyimide film was obtained in such a manner. The obtained polyimide film may be further annealed or subjected to subsequent treatment (for example, electrocorona treatment, electric treatment of plasma treatment or spray treatment).

[Metal Laminate] The polyimide film of the present invention can be preferably used for laminating with a metal layer (metal foil) to form a metal laminate.

In particular, the polyimide film of the present invention is preferably used as a circuit board, particularly a film for a flexible printed circuit board (FPC) (especially an insulating film or a cover film).

Therefore, in the present invention, a metal laminate having (using) the above polyimide film is contained. Such a metal laminate can particularly constitute a flexible printed circuit board (flexible substrate). In such a metal laminate (or substrate), the polyimide film may be laminated on the metal layer, and may constitute a base film in the metal laminate, and may constitute a coating layer (film), or may constitute the two By. For example, a metal layer (a metal layer formed with a wiring or a pattern) laminated on (formed on) the base film, and a film laminated (formed) on the metal layer (to protect the metal layer) In the metal laminate of the film or the cover film, at least one of the base film and the cover layer may be composed of the polyimide film. In particular, the polyimide film of the present invention can be preferably used at least as a substrate film (a substrate film for forming a metal layer).

The type of the metal constituting the metal layer (metal foil) is not particularly limited, and examples thereof include copper (copper element, copper alloy, etc.), stainless steel and alloy thereof, nickel (nickel alloy, nickel alloy, etc.), and aluminum (aluminum, aluminum). Alloy, etc.).

It is preferably copper. A copper foil laminate can be obtained by laminating such a metal layer with a polyimide film. Further, it is also possible to use a rustproof layer or a heat-resistant layer (for example, a plating treatment of chromium or zinc), a decane coupling agent, or the like on the surface of the metal. Preferably, it is copper and/or contains at least one of nickel, zinc, iron, chromium, cobalt, molybdenum, tungsten, vanadium, niobium, titanium, tin, manganese, aluminum, phosphorus, antimony, etc. Alloys, these can be preferably used in circuit processing. As a particularly preferable metal layer, copper or the like formed by rolling or electrolytic plating is exemplified.

The thickness of the metal layer is not particularly limited, and may be, for example, about 1 to 150 μm (for example, 3 to 50 μm).

When the metal laminate has a polyimide film and a metal layer, the form of the laminate is not particularly limited, and it depends on the purpose of use of the polyimide film (may be a substrate film or a coating layer). For example, the polyimide film may be directly laminated with the metal layer, or the polyimide film may be laminated (bonded) to the metal foil via the adhesive layer (adhesive layer).

The bonding component constituting the adhesive layer is not particularly limited, and may be, for example, any of a thermosetting resin and a thermoplastic resin.

When the metal laminate is etched to form a desired pattern wiring, it can be used for a flexible wiring board in which various components that are miniaturized and have high density are mounted. Of course, the use of the present invention is not limited to these, and it is of course applicable to various uses as long as it is a laminate including a metal layer. [Examples]

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the invention is not limited to the examples.

The following properties were measured for the polyimide films produced in the examples and the comparative examples.

[Evaluation of Dielectric Characteristics] The dielectric characteristics of the perturbation dielectric constant measuring device CP521 (for 5.8 GHz) manufactured by Agilent Technology Co., Ltd. / Kanto Electronics Application Development Co., Ltd. are connected to the network analyzer by coaxial cable. The measurement was performed at 8722A/C/D. Using a Light Magic (Series 318) thickness meter manufactured by Mitutoyo, 15 sites were arbitrarily selected from the entire film, and the thickness was measured for the 15 sites, and the average was calculated as the thickness.

[Water absorption rate] The mixture was allowed to stand in distilled water for 1 day, and was evaluated in terms of an increase in weight relative to the weight at the time of drying. Specifically, the film was cut into a circular shape having a diameter of 6 cm, and the weight (W0) after heat treatment at 200 ° C for 1 hour was measured as the weight at the time of drying, and the film was allowed to stand for one day in distilled water to absorb water. The weight (W1) was determined by the following calculation formula. Water absorption rate (%) = (W1-W0) / W0 × 100

[Evaluation of CTE (Linear Expansion Coefficient)] The measurement was carried out under the conditions of a measurement temperature range of 50 to 200 ° C and a temperature increase rate of 10 ° C/min using a TMA-50 thermomechanical analyzer manufactured by Shimadzu Corporation. The load was set to 0.25 N, and the temperature was first raised from 35 ° C at 10 ° C / min to raise the temperature to 230 ° C. The temperature was maintained at 230 ° C for 5 minutes, and then the temperature was lowered at 10 ° C / min to lower the temperature to 35 ° C, held at 35 ° C for 30 minutes, and then the temperature was raised at 10 ° C / min to raise the temperature to 230 ° C. The data of the second time from 35 ° C to 230 ° C was read, and the coefficient of linear expansion was calculated from the average of 50 to 200 ° C.

[Gelification test] A film obtained by casting a polymer onto a polyethylene terephthalate (PET) film in a catalyst/dehydrating agent mixed solution (50/50, v/v) for 2 minutes. After peeling off from the PET film, it is converted into a self-supporting film, and the polymer which can be pin-bonded to the metal frame with the needle is set to "○" (chemically closed loop). On the other hand, a polymer having a low self-supporting property and being unable to be pinned is set to "x" (chemical ring closure is not possible, and chemical ring closure is not good).

[Glass Transfer Temperature] The measurement was carried out using a dynamic viscoelasticity measuring apparatus DMS6000 manufactured by Hitachi-Hightech at a measurement temperature range of 25 to 400 ° C, a temperature increase rate of 2 ° C/min, and a frequency of 5 Hz in a nitrogen atmosphere. The temperature at the peak top of the obtained Tan δ was set as the glass transition temperature.

[Example 1] Into a 500 ml separable flask equipped with a DC stirrer, 36.0 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 33.0 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added in portions, and the mixture was stirred for 1 hour to obtain polylysine. To 100 g of the above-mentioned polyamic acid solution cooled, 18 g of β-methylpyridine, 20 g of acetic anhydride, and 10 g of N,N-dimethylacetamide were added, and cast into a glass plate using an applicator. , get a self-supporting gel film. By heat-bonding the gel film pin to a metal frame of 10 cm square, the heat treatment was carried out at 200 ° C for 30 minutes, 300 ° C for 20 minutes, and 320 ° C for 5 minutes to obtain a polyimide film having a thickness of 25 μm. (unstretched film).

[Example 2] To a 500 ml separable flask equipped with a DC stirrer, 33.5 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 21.5 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added in portions and stirred for 1 hour. Thereafter, 13.9 g of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride was introduced in portions, and the mixture was stirred for 1 hour to obtain polylysine. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Example 3] The addition amounts of 2,2'-bis(trifluoromethyl)benzidine and 3,3',4,4'-biphenyltetracarboxylic dianhydride were set to 37.3 g and 24.0 g, respectively. A laminate having a thickness of 25 μm was obtained by the same method as in Example 2 except that 4,4′-(hexafluoroisopropylidene)diphthalic anhydride was changed to 7.6 g of pyromellitic dianhydride.醯 imine film.

[Example 4] The addition amounts of 2,2'-bis(trifluoromethyl)benzidine and 3,3',4,4'-biphenyltetracarboxylic dianhydride were set to 35.7 g and 22.9 g, respectively. The same method as in Example 2 except that 4,4'-(hexafluoroisopropylidene)diphthalic anhydride was changed to 40.4 g of 4,4'-oxydiphthalic anhydride. A polyimide film having a thickness of 25 μm was obtained.

[Example 5] The addition amounts of 2,2'-bis(trifluoromethyl)benzidine and 3,3',4,4'-biphenyltetracarboxylic dianhydride were set to 32.4 g and 20.8 g, respectively. Change 4,4'-(hexafluoroisopropylidene)diphthalic anhydride to 5,5'-[1-methyl-1,1-ethanediyl bis(1,4-phenylene) A polyimide film having a thickness of 25 μm was obtained by the same method as in Example 2 except that 15.8 g of bisoxy]bis(isobenzofuran-1,3-dione) was used.

[Example 6] To a 500 ml separable flask equipped with a DC stirrer, 24.1 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 2,3',4,4'-biphenyltetracarboxylic dianhydride 22.1 g was added in portions and stirred for 1 hour. Thereafter, 13.2 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was charged and stirred for 30 minutes. To this, 9.5 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added in portions, and the mixture was stirred for 1 hour to obtain polylysine. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Example 7] The addition amounts of 2,2'-bis(trifluoromethyl)benzidine and 3,3',4,4'-biphenyltetracarboxylic dianhydride were set to 25.5 g and 23.5 g, respectively. 2,2-bis[4-(4-aminophenoxy)phenyl]propane was changed to 10.0 g of 1,3-bis(4-aminophenoxy)benzene, and thereafter, 3,3' was charged. A polyimide film having a thickness of 25 μm was obtained by the same method as in Example 6, except that 10.1 g of 4,4'-biphenyltetracarboxylic dianhydride was used.

[Example 8] The addition amounts of 2,2'-bis(trifluoromethyl)benzidine and 3,3',4,4'-biphenyltetracarboxylic dianhydride were set to 25.5 g and 23.5 g, respectively. 2,2-bis[4-(4-aminophenoxy)phenyl]propane was changed to 10.0 g of 1,4-bis(4-aminophenoxy)benzene, and thereafter, 3,3' was charged. A polyimide film having a thickness of 25 μm was obtained by the same method as in Example 6, except that 10.1 g of 4,4'-biphenyltetracarboxylic dianhydride was used.

[Example 9] The addition amounts of 2,2'-bis(trifluoromethyl)benzidine and 3,3',4,4'-biphenyltetracarboxylic dianhydride were set to 26.7 g and 24.6 g, respectively. Change 2,2-bis[4-(4-aminophenoxy)phenyl]propane to 5,5'-[1-methyl-1,1-ethanediyl bis(1,4-stretch Phenyl)dioxy]bis(isobenzofuran-1,3-dione) 7.2 g, followed by the addition of 10.5 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride, A polyimide film having a thickness of 25 μm was obtained by the same method as in Example 6 except for the same procedure as in Example 6.

[Example 10] Into a 500 ml separable flask equipped with a DC stirrer, 26.7 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 2,3',4,4'-biphenyltetracarboxylic dianhydride (24.5 g) was added in portions and stirred for 1 hour. Thereafter, 8.6 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was charged and stirred for 30 minutes. To this was added 9.3 g of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride in portions, and the mixture was stirred for 1 hour to obtain polylysine. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Example 11] 2,2'-bis(trifluoromethyl)benzidine 22.5 g, N,N-dimethylacetamide 231.0 g was placed in a 500 ml separable flask equipped with a DC stirrer. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 20.7 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added in portions and stirred for 1 hour. Thereafter, 12.4 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was charged and stirred for 30 minutes. To this was added 13.4 g of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, and the mixture was stirred for 1 hour to obtain polylysine. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Example 12] 2,2'-bis(trifluoromethyl)benzidine 26.1 g, N,N-dimethylacetamide 231.0 g was placed in a 500 ml separable flask equipped with a DC stirrer. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 3,3',4,4'-biphenyltetracarboxylic dianhydride 24.0 g was added in portions and stirred for 1 hour. Thereafter, 8.4 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was charged and stirred for 30 minutes. Into this fraction, 5,5'-[1-methyl-1,1-ethanediylbis(1,4-phenylene)dioxy]bis(isobenzofuran-1,3-di) Ketone) 10.6 g, stirred for 1 hour to obtain poly-proline. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Example 13] To a 500 ml separable flask equipped with a DC stirrer, 21.8 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 20.0 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added in portions and stirred for 1 hour. Thereafter, 12.0 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was charged and stirred for 30 minutes. Into this fraction, 5,5'-[1-methyl-1,1-ethanediylbis(1,4-phenylene)dioxy]bis(isobenzofuran-1,3-di) Ketone) 15.2 g, stirred for 1 hour to obtain poly-proline. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Example 14] The polyaminic acid solution obtained in Example 1 was cast into a glass plate shape using an applicator, heat-treated at 90 ° C for 10 minutes, and self-supporting by a heat-closed method. Gel film. The polyimine film having a thickness of 25 μm was obtained by heat-treating the gel film pin to a metal frame of a 10 cm square needle at 200 ° C for 30 minutes, 300 ° C for 20 minutes, and 320 ° C for 5 minutes. .

[Example 15] Into a 500 ml separable flask equipped with a DC stirrer, 15.0 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 3,3',4,4'-biphenyltetracarboxylic dianhydride was added in portions of 13.8 g, and the mixture was stirred for 1 hour. Thereafter, 19.3 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was charged and stirred for 30 minutes. To this was added 20.9 g of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, and the mixture was stirred for 1 hour to obtain polylysine. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Example 16] To a 500 ml separable flask equipped with a DC stirrer, 14.3 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 3,3',4,4'-biphenyltetracarboxylic dianhydride 13.1 g was added in portions and stirred for 1 hour. Thereafter, 18.3 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was charged and stirred for 30 minutes. Into this fraction, 5,5'-[1-methyl-1,1-ethanediylbis(1,4-phenylene)dioxy]bis(isobenzofuran-1,3-di) Ketone) 23.2 g, stirred for 1 hour to obtain poly-proline. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Reference Example 1] To a 500 ml separable flask equipped with a DC stirrer, 28.9 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride 40.1 g was added in portions, and the mixture was stirred for 1 hour to obtain polylysine. The polyamic acid solution was cast into a glass plate shape using an applicator, heat-treated at 90 ° C for 10 minutes, and a self-supporting gel film was obtained by a thermal ring closure method. By heat-treating the gel film pin to a metal frame with a needle of 10 cm square, at 200 ° C for 30 minutes, 300 ° C for 20 minutes, and 320 ° C for 5 minutes, a polyimide of 25 μm thick was obtained. membrane. Further, the polylysine is not suitable for the chemical ring closure method in the production of a gel film as described in the gelation test described in the following table.

[Reference Example 2] To a 500 ml separable flask equipped with a DC stirrer, 41.0 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, pyromellitic dianhydride 28.0 g was added in portions and stirred for 1 hour to obtain polyglycine. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm.

[Reference Example 3] To a 500 ml separable flask equipped with a DC stirrer, 35.0 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 4,4'-oxydiphthalic anhydride 34.0 g was added in portions, and the mixture was stirred for 1 hour to obtain poly-proline. The obtained polylysine was formed into a film by the method described in Reference Example 1 to obtain a polyimide film having a thickness of 25 μm. Further, the polylysine is not suitable for the chemical ring closure method in the production of a gel film as described in the gelation test described in the following table.

[Reference Example 4] To a 500 ml separable flask equipped with a DC stirrer, 26.3 g of 2,2'-bis(trifluoromethyl)benzidine and 231.0 g of N,N-dimethylacetamide were placed. The mixture was stirred at 40 ° C in a nitrogen bath under a nitrogen atmosphere. After stirring for 30 minutes, 5,5'-[1-methyl-1,1-ethanediylbis(1,4-phenylene)dioxy]bis(isobenzofuran-1,3- Diketone) 42.7 g fractional input, stirred for 1 hour to obtain poly-proline. The obtained polylysine was formed into a film by the method described in Example 1 to obtain a polyimide film having a thickness of 25 μm. Further, the polylysine is not suitable for the chemical ring closure method in the production of a gel film as described in the gelation test described in the following table.

The various properties of the polyimine film obtained in the above are shown together with the composition of the polyimine and the like in the following table.

Furthermore, in the tables, the meanings of the various symbols are as follows.

TFMB: 2,2'-bis(trifluoromethyl)benzidine BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane 1,3-APB: 1,3-double (4-Aminophenoxy)benzene 1,4-APB: 1,4-bis(4-aminophenoxy)benzene ODA: 4,4'-oxydiphenylamine BPDA: 3,3',4 , 4'-biphenyltetracarboxylic dianhydride 6FDA: 4,4'-(hexafluoroisopropylidene)diphthalic anhydride PMDA: pyromellitic acid dianhydride ODPA: 4,4'-oxygen Phthalic anhydride BPADA: 5,5'-[1-methyl-1,1-ethanediylbis(1,4-phenylene)dioxy]bis(isobenzofuran-1,3- Diketone) CTE: coefficient of linear expansion Tg: glass transition temperature

[Table 1] [Industrial availability]

In the present invention, a polyimide film which can be preferably used in a flexible printed circuit board use or the like can be provided.

Claims (12)

A polyimide film having a dielectric loss tangent of 0.007 or less, a water absorption ratio of 0.8% or less, and a linear expansion coefficient of 50 ppm/° C. or less at 50 to 200 °C. The polyimine film of claim 1 has a relative dielectric constant of 3.3 or less. The polyimine film according to any one of claims 1 to 2, wherein the polymerization component of the polyimine which constitutes the polyimide film is selected from the group consisting of a diamine component (A) and a tetracarboxylic acid component (B) At least one of the components contains fluorine. The polyimine film according to claim 3, wherein the diamine component (A) contains 60% by mole or more of the fluorine-containing diamine component (A1). The polyimine film according to claim 3 or 4, wherein the diamine component (A) contains 2,2'-bis(trifluoromethyl)benzidine 65 mol% or more. The polyimine film according to any one of claims 3 to 5, wherein the diamine component (A) comprises a fluorine-containing diamine component (A1) and a fluorine-free diamine component (A2). The polyimine film according to any one of claims 3 to 6, wherein the tetracarboxylic acid component (B) comprises 60 mol% or more of 3,3',4,4'-biphenyltetracarboxylic dianhydride. The polyimine film according to any one of claims 1 to 7, which is used for a base film of a copper foil laminate, and/or a cover layer. A method of producing a polyimine film according to any one of claims 1 to 8, which is obtained by a chemical ring closure method to obtain a self-supporting gel film, and is manufactured using the gel film as claimed in claims 1 to 8. Any of the polyimine films. A metal laminate using the polyimide film of any one of claims 1 to 8. The metal laminate according to claim 10, which is a copper foil laminate having a polyimide film as a base film. A metal laminate according to claim 10 or 11, wherein the polyimide film constitutes a cover layer of the protective metal layer.