Polyimide composition, resin film, laminate, cover lay film, copper foil with resin, metal-clad laminate and circuit board

Abstract

To provide a polyimide composition and a resin film which use a certain amount or more of a dimer diamine composition mainly containing dimer diamine as a raw material and nonetheless are adaptable to higher frequency of electronic equipment by improvement of dielectric characteristics.SOLUTION: A polyimide composition contains: (A) polyimide obtained by reacting a tetracarboxylic acid anhydride component, with a diamine component containing 40 mol% or more of a dimer diamine composition mainly containing dimer diamine obtained by substituting two terminal carboxylic acid groups of a dimer acid with primary aminomethyl groups or amino groups, with respect to the total diamine component; and (B) aromatic condensed phosphate, wherein a weight ratio of the component (B) to the component (A) is within a range of 0.05 to 0.7, and a weight ratio of phosphorus derived from the component (B) to the dimer diamine composition in the component (A) is within a range of 0.01 to 0.15.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyimide composition useful as an adhesive in a circuit board such as a printed wiring board, a resin film using the same, a laminate, a coverlay film, a copper foil with resin, a metal-clad laminate, and a circuit board.

Background Art

[0002] In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, there has been an increasing demand for flexible printed circuit boards (FPCs) that are thin, lightweight, flexible, and have excellent durability even when repeatedly bent. Since FPCs enable three-dimensional and high-density mounting even in limited space, their applications are expanding, for example, to wirings in movable parts of electronic devices such as HDDs, DVDs, and mobile phones, and to components such as cables and connectors.

[0003] In addition to the above-mentioned high density, with the progress of high performance of devices, it has also become necessary to cope with high-frequency transmission signals. In information processing and information communication, efforts are being made to increase the transmission frequency in order to transmit and process large-capacity information, and printed circuit board materials are required to reduce transmission loss by thinning the insulating layer and improving the dielectric properties of the insulating layer. In the future, FPCs and adhesives that can cope with high frequencies will be required, and reduction of transmission loss will be important.

[0004] By the way, as a technology related to an adhesive layer mainly composed of polyimide, a polyimide obtained from a diamine compound derived from an aliphatic diamine such as dimer acid (dimer fatty acid) as a raw material, and an amino compound having at least two primary amino groups as functional groups are reacted to obtain a crosslinked polyimide resin, which has been proposed to be applied to the adhesive layer of a coverlay film (for example, Patent Document 1). In addition, it has been proposed to apply a resin composition in which such a polyimide, a thermosetting resin such as an epoxy resin, and a crosslinking agent are used in combination to a copper-clad laminate (for example, Patent Document 2). However, in Patent Documents 1 and 2, no consideration is given to the influence of by-products other than dimer diamine derived from dimer acid contained in the raw materials.

[0005] Dimer acid is a dimerized fatty acid obtained by subjecting natural fatty acids such as soybean oil fatty acid, tall oil fatty acid, rapeseed oil fatty acid, and oleic acid, linoleic acid, linolenic acid, erucic acid, etc. obtained by purifying these to a Diels-Alder reaction as raw materials, and it is known that a polybasic acid compound derived from dimer acid can be obtained as a composition of the raw material fatty acid or fatty acids trimerized or higher (for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] As a means of controlling the physical properties of a resin mainly composed of polyimide, it is important to control the molecular weight of polyamic acid or polyimide, which is a precursor of polyimide. However, when using a dimer diamine as a raw material, it is used in a state containing by-products other than the dimer diamine derived from dimer acid. Such by-products not only make it difficult to control the molecular weight of polyimide, but also affect the dielectric properties in a wide range of frequencies and their humidity dependence.

[0008] An object of the present invention is to provide a polyimide composition and a resin film capable of coping with the high-frequencyization of electronic devices by improving dielectric properties while using a certain amount or more of a dimer diamine composition mainly composed of dimer diamine as a raw material. [Means for Solving the Problems]

[0009] The polyimide composition of the present invention comprises the following components (A) and (B); (A) A polyimide obtained by reacting a tetracarboxylic anhydride component with a diamine component containing 40 mol% or more of a dimer diamine composition mainly composed of a dimer diamine in which two terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups, and (B) Aromatic condensed phosphate ester, and the weight ratio of the component (B) to the component (A) is in the range of 0.05 to 0.7.

[0010] In the polyimide composition of the present invention, the weight ratio of the component (B) to the component (A) may be in the range of 0.2 to 0.5.

[0011] In the polyimide composition of the present invention, the weight ratio of phosphorus derived from the component (B) to the component (A) may be in the range of 0.01 to 0.1.

[0012] In the polyimide composition of the present invention, the weight ratio of phosphorus derived from the component (B) to the dimer diamine composition in the component (A) may be in the range of 0.01 to 0.15.

[0013] The polyimide composition of the present invention may further contain an amino compound having at least two primary amino groups as functional groups.

[0014] The resin film of the present invention is a resin film containing a polyimide layer, wherein the polyimide layer contains the following components (A) and (B); (A) A polyimide obtained by reacting a tetracarboxylic anhydride component with a diamine component containing 40 mol% or more of a dimer diamine composition mainly composed of a dimer diamine in which two terminal carboxylic acid groups of a dimer acid are substituted with a primary aminomethyl group or an amino group, based on the total diamine component, and (B) an aromatic condensed phosphate ester, and the weight ratio of the component (B) to the component (A) is in the range of 0.05 to 0.7.

[0015] The laminate of the present invention is a laminate having a base material and an adhesive layer laminated on at least one surface of the base material, characterized in that the adhesive layer is made of the above resin film.

[0016] The coverlay film of the present invention is a coverlay film having a coverlay film material layer and an adhesive layer laminated on the coverlay film material layer, characterized in that the adhesive layer is made of the above resin film.

[0017] The copper foil with resin of the present invention is a copper foil with resin in which an adhesive layer and a copper foil are laminated, characterized in that the adhesive layer is made of the above resin film.

[0018] The metal-clad laminate of the present invention is a metal-clad laminate having an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, characterized in that at least one layer of the insulating resin layer is made of the above resin film.

[0019] The circuit board of the present invention is a circuit board formed by wiring the metal layer of the metal-clad laminate.

Advantages of the Invention

[0020] Since the polyimide composition of the present invention contains a polyimide derived from a diamine mainly composed of a dimer diamine and an aromatic condensed phosphate ester, a resin film excellent in dielectric properties can be formed. Further, the resin film of the present invention has low humidity dependence of dielectric properties and excellent stability. Therefore, the polyimide composition and the resin film of the present invention can be particularly preferably used for circuit boards such as FPCs in electronic devices that require high-speed signal transmission, for example.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described. The polyimide composition of the present embodiment contains the following components (A) and (B); (A) A polyimide obtained by reacting a tetracarboxylic anhydride component with a diamine component containing 40 mol% or more of a dimer diamine composition mainly composed of a dimer diamine in which two terminal carboxylic acid groups of a dimer acid are substituted with a primary aminomethyl group or an amino group, based on the total diamine component, and (B) an aromatic condensed phosphate ester, and the weight ratio of the component (B) to the component (A) is in the range of 0.05 to 0.7.

[0022] [(A) component; polyimide] The polyimide of the component (A) is obtained by imidizing a polyamic acid which is a precursor obtained by reacting a tetracarboxylic anhydride component with a diamine component containing 40 mol% or more of a dimer diamine composition mainly composed of a dimer diamine in which two terminal carboxylic acid groups of a dimer acid are substituted with a primary aminomethyl group or an amino group, based on the total diamine component.

[0023] (Tetracarboxylic anhydride component) The polyimide of this embodiment can generally contain, without particular limitation, tetracarboxylic acid residues derived from tetracarboxylic dianhydrides used in thermoplastic polyimides. However, it is preferable that the total amount of tetracarboxylic acid residues derived from the tetracarboxylic dianhydride represented by the following general formula (1) is 90 mol% or more with respect to all the tetracarboxylic acid residues. By containing 90 mol% or more in total of the tetracarboxylic acid residues derived from the tetracarboxylic dianhydride represented by the following general formula (1) with respect to all the tetracarboxylic acid residues, it is easy to achieve both flexibility and heat resistance of the polyimide, which is preferable. If the total of the tetracarboxylic acid residues derived from the tetracarboxylic dianhydride represented by the following general formula (1) is less than 90 mol%, the solvent solubility of the polyimide tends to decrease.

[0024]

Chemical formula

[0025] In the general formula (1), X represents a single bond or a divalent group selected from the following formulas.

[0026]

Chemical formula

[0027] In the above formula, Z is -C 6 H 4 -, -(CH 2 )n- or -CH 2 -CH(-O-C(=O)-CH 3 )-CH 2 -, where n represents an integer from 1 to 20.

[0028] Note that "thermoplastic polyimide" generally refers to a polyimide for which the glass transition temperature (Tg) can be clearly confirmed. In the present invention, the storage modulus at 30°C measured using a dynamic viscoelasticity measuring device (DMA) is 1.0×10 8 Pa or more, and the storage modulus at 300°C is 3.0×10 7It refers to a polyimide with less than Pa. Also, "non-thermoplastic polyimide" generally means a polyimide that does not show softening or adhesiveness even when heated. In the present invention, the storage modulus at 30 °C measured using a dynamic viscoelasticity measuring device (DMA) is 1.0×10 9 Pa or more, and the storage modulus at 300 °C is 3.0×10 8 Pa or more.

[0029] Examples of the tetracarboxylic dianhydride represented by the general formula (1) include 3,3’,4,4’-biphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 3,3’,4,4’-diphenylsulfone tetracarboxylic dianhydride (DSDA), 4,4’-oxydiphthalic anhydride (ODPA), 4,4’-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), p-phenylene bis(trimellitic acid monoester anhydride) (TAHQ), ethylene glycol bisanhydrotrimellitate (TMEG), and the like. Among these, when using 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) in particular, the adhesiveness of the polyimide can be improved, and there may be a case where the ketone group present in the molecular skeleton reacts with the amino group of the amino compound for crosslinking formation described later to form a C=N bond, and the effect of improving heat resistance is likely to be exhibited. From such a viewpoint, it is preferable to contain a tetracarboxylic acid residue derived from BTDA in an amount of preferably 50 mol% or more, more preferably 60 mol% or more, based on all the tetracarboxylic acid residues.

[0030] (A) The polyimide may contain a tetracarboxylic acid residue derived from an acid anhydride other than the tetracarboxylic acid anhydride represented by the general formula (1) within a range not impairing the effects of the invention.Such tetracarboxylic acid residues are not particularly limited, and examples thereof include pyromellitic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'- or 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 2,3',3,4'-diphenyl ether tetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, 3,3'',4,4''-, 2,3,3'',4''- or 2,2'',3,3''-p-terphenyltetracarboxylic dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)-propane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl) methane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis(2,3- or 3,4-dicarboxyphenyl) ethane dianhydride, 1,2,7,8-, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-(or 1,4,5,8-)tetrachloronaphthalene-1,4,5,8-(or 2,3,6,7-)tetracarboxylic dianhydride, 2,3,8,9-, 3,4,9,10-, 4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy) diphenylmethane dianhydride, and tetracarboxylic acid residues derived from aromatic tetracarboxylic dianhydrides such as these.

[0031] (Diamine component) The polyimide of component (A) uses, as a raw material, a diamine component containing 40 mol% or more, more preferably 60 mol% or more, of a dimer diamine composition with respect to the total diamine component. That is, the polyimide of component (A) contains 40 mol% or more, preferably 60 mol% or more, of diamine residues derived from the dimer diamine composition with respect to the total diamine residues. By using the dimer diamine composition in the above amount, the dielectric properties of the polyimide can be improved, and the thermal pressure bonding properties can be improved by lowering the glass transition temperature (lowering Tg) of the polyimide, and the internal stress can be relaxed by reducing the elastic modulus.

[0032] (Dimer diamine composition) The dimer diamine composition contains the following component (a) as a main component, and the amounts of components (b) and (c) are controlled.

[0033] (a) Dimer diamine; The dimer diamine of component (a) means that two terminal carboxylic acid groups (-COOH) of dimer acid are primary aminomethyl groups (-CH 2 -NH 2 ) or amino groups (-NH 2It means a diamine substituted with [[ID=]]. Dimer acid is a known dibasic acid obtained by the intermolecular polymerization reaction of unsaturated fatty acids. Its industrial manufacturing process is almost standardized in the industry and is obtained by dimerizing unsaturated fatty acids with 11 to 22 carbon atoms using a clay catalyst or the like. Industrially obtained dimer acid is mainly composed of a dibasic acid with 36 carbon atoms obtained by dimerizing unsaturated fatty acids with 18 carbon atoms such as oleic acid, linoleic acid, and linolenic acid. Depending on the degree of purification, it contains an arbitrary amount of monomeric acid (18 carbon atoms), trimeric acid (54 carbon atoms), and other polymerized fatty acids with 20 to 54 carbon atoms. Also, although double bonds remain after the dimerization reaction, in the present invention, those further hydrogenated to reduce the degree of unsaturation are also included in the dimer acid. The dimer diamine of component (a) can be defined as a diamine compound obtained by substituting the terminal carboxylic acid group of a dibasic acid compound within the range of 18 to 54 carbon atoms, preferably within the range of 22 to 44 carbon atoms, with a primary aminomethyl group or an amino group.

[0034] As a characteristic of the dimer diamine, it is possible to impart characteristics derived from the skeleton of the dimer acid. That is, since the dimer diamine is a huge aliphatic molecule with a molecular weight of about 560 to 620, it can increase the molar volume of the molecule and relatively reduce the polar groups of the polyimide. Such characteristics of the dimer acid type diamine are considered to contribute to improving the dielectric properties by reducing the dielectric constant and dielectric tangent while suppressing the decrease in the heat resistance of the polyimide. Also, since it has two freely moving hydrophobic chains with 7 to 9 carbon atoms and two chain-like aliphatic amino groups with a length close to 18 carbon atoms, it not only gives flexibility to the polyimide but also enables the polyimide to have an asymmetric chemical structure or a non-planar chemical structure, so it is considered possible to achieve a low dielectric constant of the polyimide.

[0035] The dimer diamine composition is preferably one in which the content of the dimer diamine in component (a) is increased to 96% by weight or more, preferably 97% by weight or more, more preferably 98% by weight or more, by a purification method such as molecular distillation. By setting the content of the dimer diamine in component (a) to 96% by weight or more, the spread of the molecular weight distribution of the polyimide can be suppressed. If technically possible, it is most preferable that all (100% by weight) of the dimer diamine composition is composed of the dimer diamine in component (a).

[0036] (b) A monoamine compound obtained by substituting the terminal carboxylic acid group of a monobasic acid compound having 10 to 40 carbon atoms with a primary aminomethyl group or an amino group; The monobasic acid compound having 10 to 40 carbon atoms is a mixture of a monobasic unsaturated fatty acid having 10 to 20 carbon atoms derived from the raw material of dimer acid and a monobasic acid compound having 21 to 40 carbon atoms which is a by-product in the production of dimer acid. The monoamine compound is obtained by substituting the terminal carboxylic acid group of these monobasic acid compounds with a primary aminomethyl group or an amino group.

[0037] The monoamine compound in component (b) is a component that suppresses the increase in the molecular weight of the polyimide. During the polymerization of the polyamic acid or polyimide, the monofunctional amino group of the monoamine compound reacts with the terminal acid anhydride group of the polyamic acid or polyimide, thereby sealing the terminal acid anhydride group and suppressing the increase in the molecular weight of the polyamic acid or polyimide.

[0038] (c) An amine compound obtained by substituting the terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group having 41 to 80 carbon atoms with a primary aminomethyl group or an amino group (excluding the dimer diamine); The polybasic acid compound having a hydrocarbon group within the range of carbon numbers 41 to 80 is a polybasic acid compound mainly composed of a tribasic acid compound within the range of carbon numbers 41 to 80, which is a by-product in the production of dimer acid. Further, it may contain a polymerized fatty acid other than dimer acid having carbon numbers 41 to 80. The amine compound is obtained by substituting the terminal carboxylic acid group of these polybasic acid compounds with a primary aminomethyl group or an amino group.

[0039] (c) The amine compound in the component is a component that promotes an increase in the molecular weight of the polyimide. A trifunctional or higher amino group mainly composed of a triamine body derived from trimer acid reacts with the terminal acid anhydride group of polyamic acid or polyimide, rapidly increasing the molecular weight of the polyimide. Further, an amine compound derived from a polymerized fatty acid other than dimer acid having carbon numbers 41 to 80 also increases the molecular weight of the polyimide and causes gelation of polyamic acid or polyimide.

[0040] When quantifying each component of the dimer diamine composition by measurement using gel permeation chromatography (GPC), in order to facilitate the confirmation of the peak start, peak top, and peak end of each component of the dimer diamine composition, a sample obtained by treating the dimer diamine composition with acetic anhydride and pyridine is used, and cyclohexanone is used as an internal standard substance. Using the sample thus prepared, each component is quantified by the area percentage of the GPC chromatogram. The peak start and peak end of each component are taken as the minimum values of each peak curve, and based on this, the area percentage of the chromatogram can be calculated.

[0041] Further, in the dimer diamine composition used in the present invention, in terms of the area percentage of the chromatogram obtained by GPC measurement, the total of components (b) and (c) is preferably 4% or less, more preferably less than 4%. By setting the total of components (b) and (c) to 4% or less, the spread of the molecular weight distribution of the polyimide can be suppressed.

[0042] Also, the area percentage of the chromatogram of component (b) is preferably 3% or less, more preferably 2% or less, still more preferably 1% or less. By setting it within such a range, a decrease in the molecular weight of the polyimide can be suppressed, and furthermore, the range of the molar ratio of the tetracarboxylic dianhydride component and the diamine component can be widened. Note that component (b) may not be contained in the dimer diamine composition.

[0043] Also, the area percentage of the chromatogram of component (c) is 2% or less, preferably 1.8% or less, more preferably 1.5% or less. By setting it within such a range, a rapid increase in the molecular weight of the polyimide can be suppressed, and furthermore, an increase in the dielectric tangent at a wide range of frequencies of the resin film can be suppressed. Note that component (c) may not be contained in the dimer diamine composition.

[0044] Also, when the ratio (b / c) of the area percentages of the chromatograms of components (b) and (c) is 1 or more, the molar ratio (tetracarboxylic dianhydride component / diamine component) of the tetracarboxylic dianhydride component and the diamine component is preferably 0.97 or more and less than 1.0. By setting such a molar ratio, the control of the molecular weight of the polyimide becomes easier.

[0045] Also, when the ratio (b / c) of the area percentages of the chromatograms of components (b) and (c) is less than 1, the molar ratio (tetracarboxylic dianhydride component / diamine component) of the tetracarboxylic dianhydride component and the diamine component is preferably 0.97 or more and 1.1 or less. By setting such a molar ratio, the control of the molecular weight of the polyimide becomes easier.

[0046] The weight-average molecular weight of the polyimide is preferably in the range of, for example, 10,000 to 200,000. If it is within such a range, it becomes easy to control the weight-average molecular weight of the polyimide. Further, for example, when applied as an adhesive for FPC, the weight-average molecular weight of the polyimide is more preferably in the range of 20,000 to 150,000, and even more preferably in the range of 40,000 to 150,000. When the weight-average molecular weight of the polyimide is less than 20,000, the flow resistance tends to deteriorate. On the other hand, when the weight-average molecular weight of the polyimide exceeds 150,000, the viscosity increases excessively and it becomes insoluble in the solvent, and unevenness in the thickness of the adhesive layer, streaks, and other defects are likely to occur during the coating operation.

[0047] The dimer diamine composition used in the present invention is preferably purified for the purpose of reducing components other than the dimer diamine of component (a). The purification method is not particularly limited, but known methods such as distillation method and precipitation purification are suitable. The dimer diamine composition before purification is available as a commercially available product, and examples include PRIAMINE 1073 (trade name), PRIAMINE 1074 (trade name), and PRIAMINE 1075 (trade name) manufactured by Clariant Japan Co., Ltd.

[0048] Examples of diamine compounds other than dimer diamine used in polyimide include aromatic diamine compounds and aliphatic diamine compounds. Specific examples thereof include 1,4-diaminobenzene (p-PDA; paraphenylenediamine), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-n-propyl-4,4'-diaminobiphenyl (m-NPB), 4-aminophenyl-4'-aminobenzoate (APAB), 2,2-bis-[4-(3-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)biphenyl, bis[1-(3-aminophenoxy)]biphenyl, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)]benzophenone, 9,9-bis[4-(3-aminophenoxy)phenyl]fluorene, 2,2-bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis-[4-(3-aminophenoxy)phenyl]hexafluoropropane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3''-diamino-p-terphenyl, 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, bis(p-aminocyclohexyl)methane, bis(p-β-amino-t-butylphenyl)ether, bis(p-β-methyl-δ-aminopentyl)benzene, p-bis(2-methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis(β-amino-t-butyl)toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,Examples of the diamine compound include 5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2'-methoxy-4,4'-diaminobenzanilide, 4,4'-diaminobenzanilide, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 6-amino-2-(4-aminophenoxy)benzoxazole, 1,3-bis(3-aminophenoxy)benzene, etc.

[0049] The polyimide can be produced by reacting the above tetracarboxylic dianhydride component and diamine component in a solvent to form a polyamic acid and then subjecting it to thermal ring closure. For example, the tetracarboxylic dianhydride component and diamine component are dissolved in an organic solvent in approximately equimolar amounts and stirred at a temperature in the range of 0 to 100°C for 30 minutes to 24 hours to carry out a polymerization reaction, whereby a polyamic acid, which is a precursor of the polyimide, is obtained. In the reaction, the reaction components are dissolved so that the resulting precursor is in the range of 5 to 50% by weight, preferably in the range of 10 to 40% by weight, in the organic solvent. Examples of the organic solvent used in the polymerization reaction include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, methylcyclohexane, dioxane, tetrahydrofuran, diglyme, triglyme, methanol, ethanol, benzyl alcohol, cresol, etc. These solvents can also be used in combination of two or more, and furthermore, the combined use of aromatic hydrocarbons such as xylene and toluene is also possible. Also, the amount of such an organic solvent used is not particularly limited, but it is preferably adjusted to an amount such that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 50% by weight.

[0050] The synthesized polyamic acid is usually advantageously used as a reaction solvent solution, but can be concentrated, diluted or replaced with other organic solvents if necessary. Also, since polyamic acid generally has excellent solvent solubility, it is preferably used. The viscosity of the solution of polyamic acid is preferably in the range of 500 cps to 100,000 cps. If it is outside this range, defects such as film thickness unevenness and streaks are likely to occur during the coating operation by a coater or the like.

[0051] The method of imidizing polyamic acid to form polyimide is not particularly limited. For example, heat treatment such as heating in the above solvent at a temperature condition in the range of 80 to 400 °C for 1 to 24 hours is preferably employed. Also, the temperature may be heated under constant temperature conditions, or the temperature can be changed during the process.

[0052] In the polyimide of the present embodiment, by selecting the types of the above tetracarboxylic dianhydride component and diamine component, and the respective molar ratios in the case of applying two or more tetracarboxylic dianhydride components or diamine components, dielectric properties, coefficient of thermal expansion, tensile elastic modulus, glass transition temperature, etc. can be controlled. Also, in the polyimide of the present embodiment, when there are a plurality of structural units of polyimide, they may exist as blocks or randomly, but it is preferably random.

[0053] The imide group concentration of the polyimide of the present embodiment is preferably 22% by weight or less, more preferably 20% by weight or less. Here, the "imide group concentration" means the value obtained by dividing the molecular weight of the imide group (- (CO) 2 -N-) by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 22% by weight, the molecular weight of the resin itself decreases, and the low moisture absorption property deteriorates due to the increase in polar groups, and Tg and elastic modulus increase.

[0054] The polyimide of this embodiment preferably has a completely imidized structure. However, a part of the polyimide may be an amic acid. The imidization rate can be measured by using a Fourier transform infrared spectrophotometer (commercially available product: FT / IR620 manufactured by JASCO Corporation) and measuring the infrared absorption spectrum of the polyimide thin film by the single reflection ATR method, and is based on the benzene ring absorber near 1015 cm -1 and can be calculated from the absorbance of the C=O stretching derived from the imide group at 1780 cm -1 .

[0055] [Component (B); Aromatic Condensed Phosphate Ester] The polyimide composition of this embodiment contains the aromatic condensed phosphate ester as the component (B). Here, the "aromatic condensed phosphate ester" means a phosphate ester compound having a chemical structure in which two or more phosphate ester units are linked by a divalent organic group having an aromatic ring, or a reaction product of phosphorus oxychloride, a divalent phenolic compound, and phenol or alkylphenol. By combining the aromatic condensed phosphate ester with a polyimide obtained by using a diamine composition in a certain amount or more, the dielectric properties can be improved. The reason is not yet clear, but due to the specific chemical structure of the aromatic condensed phosphate ester, although there is compatibility between the dielectric properties of the aromatic condensed phosphate ester itself and the polyimide obtained by using the diamine composition, it is presumed that it contributes to lowering the dielectric constant and the dielectric tangent because it does not excessively increase the mobility of the molecular chain.

[0056] Preferred examples of the aromatic condensed phosphate ester include compounds having the structure of the following general formula (2).

[0057] [Chemical formula]

[0058] In general formula (2), each of the plurality of Rs is an aromatic hydrocarbon group which may independently have a substituent, Ar is a divalent organic group having an aromatic ring, and n means an integer of 1 or more. The aromatic condensed phosphate ester represented by general formula (2) may be a dimer where n is 1, or a multimer where n is 2 or more. Also, it may be not limited to a single compound but a mixture.

[0059] Examples of the aromatic hydrocarbon group which may have a substituent and is represented by R in general formula (2) include aryl groups having 6 to 15 carbon atoms. More specifically, examples include a phenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, an ethylphenyl group, a butylphenyl group, a nonylphenyl group, and the like. In general formula (2), preferable examples of the divalent organic group represented by Ar include, for example, an alkylene group, an arylene group, etc., and these may have a substituent. More preferable examples include a phenylene group and a group represented by the following formula (3).

[0060]

Chemical formula

[0061] In formula (3), Y is a single bond, -CH 2 -, -C(CH 3 ) 2 -, -SO 2 -, -C 5 H 10 -, -C 6 H 12 -, -C 7 H 14 -, -C 8 H 16 -, etc. Among the groups represented by formula (3), a biphenyldiyl group where Y is a single bond is more preferable.

[0062] Examples of the aromatic condensed phosphate ester include resorcinol bis-diphenyl phosphate, resorcinol bis-dixylenyl phosphate, bisphenol A bis-diphenyl phosphate, and the like. As these aromatic condensed phosphate esters, commercially available products can be obtained. Examples thereof include CR-733S (trade name), CR-741 (trade name), CR-747 (trade name), PX-200 (trade name), PX-200B (trade name) [manufactured by Daihachi Chemical Industry Co., Ltd., etc.]. These aromatic condensed phosphate esters may be used in combination of two or more.

[0063] [Blending amount] In the polyimide composition of this embodiment, the weight ratio of the component (B) to the component (A) is in the range of 0.05 to 0.7, and preferably in the range of 0.2 to 0.5 in consideration of film physical properties such as the tensile modulus when forming a resin film. If the weight ratio of the component (B) to the component (A) is less than 0.05, the improvement of dielectric properties may be insufficient. If it exceeds 0.7, the formation of polyimide may be difficult, and the resulting polyimide film may be embrittled. By setting the blending amount of the component (B) within the above range, the dielectric properties can be improved.

[0064] Further, in the polyimide composition of this embodiment, the component (B) is preferably blended so that the weight ratio of phosphorus derived from the component (B) to the polyimide of the component (A) is in the range of 0.01 to 0.1. If the weight ratio of phosphorus derived from the component (B) is less than 0.01, the improvement of dielectric properties may be insufficient, and if it exceeds 0.1, the polyimide film (or polyimide layer) may be embrittled.

[0065] In the polyimide composition of this embodiment, it is preferable that the weight ratio of phosphorus derived from component (B) to the dimer diamine composition contained in component (A) {(phosphorus derived from component (B)) / (dimer diamine composition in component (A))} is in the range of 0.01 to 0.15. If it is less than the above lower limit, the improvement of dielectric properties may be insufficient. If it exceeds the above upper limit, the formation of polyimide may become difficult, and the resulting polyimide film may be embrittled.

[0066] <Crosslink formation> When the polyimide of component (A) has a ketone group, a crosslinked structure can be formed by reacting the ketone group with the amino group of an amino compound having at least two primary amino groups as functional groups (hereinafter sometimes referred to as "amino compound for crosslink formation") to form a C=N bond. By forming the crosslinked structure, the heat resistance of the thermoplastic polyimide forming the adhesive layer can be improved. Preferred tetracarboxylic dianhydrides for forming a thermoplastic polyimide having a ketone group include, for example, 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA). Examples of diamine compounds include aromatic diamines such as 4,4'-bis(3-aminophenoxy)benzophenone (BABP) and 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene (BABB).

[0067] For the purpose of forming a crosslinked structure, the polyimide composition of this embodiment preferably contains, in particular, a polyimide of component (A) containing a BTDA residue derived from BTDA, preferably 50 mol% or more, more preferably 60 mol% or more, based on all tetracarboxylic acid residues, and an amino compound for crosslink formation. In the present invention, the "BTDA residue" means a tetravalent group derived from BTDA.

[0068] Examples of the amino compound for forming a bridge include (I) dihydrazide compounds, (II) aromatic diamines, (III) aliphatic amines, etc. Among these, dihydrazide compounds are preferred. Aliphatic amines other than dihydrazide compounds are likely to form a crosslinked structure even at room temperature, raising concerns about the storage stability of the varnish. On the other hand, aromatic diamines need to be heated to a high temperature to form a crosslinked structure. Thus, when using a dihydrazide compound, it is possible to achieve both the storage stability of the varnish and the shortening of the curing time. Examples of the dihydrazide compound include dihydrazide oxalate, dihydrazide malonate, dihydrazide succinate, dihydrazide glutarate, dihydrazide adipate, dihydrazide pimelate, dihydrazide suberate, dihydrazide azelate, dihydrazide sebacate, dihydrazide dodecanedioate, dihydrazide maleate, dihydrazide fumarate, dihydrazide diglycolate, dihydrazide tartrate, dihydrazide malate, dihydrazide phthalate, dihydrazide isophthalate, dihydrazide terephthalate, dihydrazide 2,6-naphthalenedicarboxylate, dihydrazide 4,4-bisbenzenedicarboxylate, dihydrazide 1,4-naphthalenedicarboxylate, dihydrazide 2,6-pyridinedicarboxylate, dihydrazide itaconate, etc. These dihydrazide compounds may be used alone or in combination of two or more.

[0069] In addition, the amino compounds such as the above (I) dihydrazide compounds, (II) aromatic diamines, and (III) aliphatic amines can also be used in combination of two or more across categories, such as a combination of (I) and (II), a combination of (I) and (III), and a combination of (I), (II), and (III).

[0070] Also, from the perspective of making the network structure formed by crosslinking with the amino compound for crosslinking formation denser, the amino compound for crosslinking formation used in the present invention preferably has a molecular weight (weight average molecular weight when the amino compound for crosslinking formation is an oligomer) of 5,000 or less, more preferably 90 to 2,000, and still more preferably 100 to 1,500. Among these, an amino compound for crosslinking formation having a molecular weight of 100 to 1,000 is particularly preferred. When the molecular weight of the amino compound for crosslinking formation is less than 90, only one amino group of the amino compound for crosslinking formation forms a C=N bond with the ketone group of the polyimide resin, and the periphery of the remaining amino groups becomes sterically bulky, so the remaining amino groups tend to be less likely to form a C=N bond.

[0071] When crosslinking the ketone group in the polyimide of component (A) with the amino compound for crosslinking formation, the amino compound for crosslinking formation is added to the resin solution containing component (A) to cause a condensation reaction between the ketone group in the polyimide and the primary amino group of the amino compound for crosslinking formation. By this condensation reaction, the resin solution cures to form a cured product. In this case, the addition amount of the amino compound for crosslinking formation can be such that the total amount of primary amino groups is 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, more preferably 0.03 mol to 0.9 mol, and most preferably 0.04 mol to 0.6 mol per 1 mol of the ketone group. When the addition amount of the amino compound for crosslinking formation is such that the total amount of primary amino groups is less than 0.004 mol per 1 mol of the ketone group, the crosslinking by the amino compound for crosslinking formation is not sufficient, so the heat resistance after curing tends not to be exhibited. When the addition amount of the amino compound for crosslinking formation exceeds 1.5 mol, the unreacted amino compound for crosslinking formation acts as a plasticizer and tends to reduce the heat resistance as an adhesive layer.

[0072] The conditions for the condensation reaction for crosslink formation are not particularly limited as long as the ketone group in the polyimide of component (A) reacts with the primary amino group of the above crosslink-forming amino compound to form an imine bond (C=N bond). The temperature for the heat condensation is preferably in the range of, for example, 120 to 220°C, more preferably in the range of 140 to 200°C, for reasons such as releasing the water generated by the condensation out of the system or simplifying the condensation step when the heat condensation reaction is subsequently carried out after the synthesis of the polyimide of component (A). The reaction time is preferably about 30 minutes to 24 hours. The end point of the reaction can be confirmed, for example, by measuring the infrared absorption spectrum using a Fourier transform infrared spectrophotometer (commercially available product: FT / IR620 manufactured by JASCO Corporation), by the decrease or disappearance of the absorption peak derived from the ketone group in the polyimide resin near 1670 cm -1 and the appearance of the absorption peak derived from the imine group near 1635 cm -1 .

[0073] The heat condensation of the ketone group of the polyimide of component (A) and the primary amino group of the above crosslink-forming amino compound can be carried out, for example, (1) A method in which, following the synthesis (imidization) of the polyimide of component (A), the crosslink-forming amino compound is added and heated, (2) A method in which an excessive amount of the amino compound is charged in advance as the diamine component, and following the synthesis (imidization) of the polyimide of component (A), the remaining amino compound that does not participate in the imidization or amidation is utilized as the crosslink-forming amino compound and heated together with the polyimide, or (3) A method in which the composition of the polyimide of component (A) added with the above crosslink-forming amino compound is processed into a predetermined shape (for example, after coating on an arbitrary substrate or after forming into a film shape) and then heated, etc.

[0074] For imparting heat resistance to the polyimide of component (A), the formation of an imine bond by forming a crosslinked structure was described, but it is not limited thereto. As a method for curing the polyimide of component (A), for example, it is also possible to blend and cure a compound having an unsaturated bond such as an epoxy resin, an epoxy resin curing agent, maleimide, an activated ester resin, or a resin having a styrene skeleton.

[0075] [Optional component] The polyimide composition of the present embodiment preferably further contains an inorganic filler as an optional component in addition to the amino compound for crosslink formation. Further, if necessary, other optional components such as a plasticizer, an epoxy resin, a fluororesin, other resin components such as an olefin-based resin, a curing accelerator, a coupling agent, an organic filler, a pigment, a flame retardant, etc. can be appropriately blended. However, since some plasticizers contain many polar groups and there is a concern that they may promote the diffusion of copper from copper wiring, it is preferable not to use plasticizers as much as possible. Furthermore, the polyimide composition of the present embodiment can contain a solvent such as an organic solvent. Examples of the organic solvent include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, cresol, etc. These solvents can also be used in combination of two or more, and further, a combination of aromatic hydrocarbons such as xylene and toluene is also possible. The content of the organic solvent is not particularly limited, but it is preferably adjusted to an amount such that the concentration of the polyamic acid or polyimide is about 5 to 30% by weight.

[0076] [Preparation of polyimide composition] When preparing the polyimide composition, for example, the component (B) may be directly added to a resin solution of polyamic acid or polyimide prepared using an arbitrary solvent. Alternatively, considering the solubility and the mixing / dispersibility of the component (B), the component (B) may be previously added to a reaction solvent in which either the acid dianhydride component or the diamine component, which is a raw material of polyamic acid, has been added, and then the other raw material may be added under stirring to proceed with the polymerization. In any method, the entire amount of the component (B) may be added at once, or it may be added little by little in several portions. Also, the raw materials may be put in all at once, or may be mixed little by little in several times.

[0077] When an adhesive layer is formed using the polyimide composition of this embodiment, it has excellent flexibility and thermoplasticity, and has preferable characteristics as an adhesive for a coverlay film that protects wiring portions such as FPC and rigid-flex circuit boards.

[0078] [Resin film] The resin film of this embodiment is a resin film containing a polyimide layer, and the polyimide layer is formed by forming a film with the solid content (the remainder excluding the solvent) of the above polyimide composition as a main component. That is, the resin film of this embodiment contains the component (A) and the component (B), and the weight ratio of the component (B) to the component (A) is within the range of 0.05 to 0.7. The resin film of this embodiment contains, as a resin component, a polyimide obtained by reacting a tetracarboxylic dianhydride component with a diamine component containing 40 mol% or more of a dimer diamine composition mainly composed of a dimer diamine in which two terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups, in order to impart excellent high-frequency characteristics and stability against humidity. Note that the resin film of this embodiment may contain, as an arbitrary component other than the resin component, for example, a filler.

[0079] The resin film of the present embodiment is not particularly limited as long as it is a film of an insulating resin containing a polyimide layer formed from the above polyimide composition, and may be a film (sheet) made of an insulating resin, or may be a film of an insulating resin laminated on a base material such as a resin sheet such as a copper foil, a glass plate, a polyimide-based film, a polyamide-based film, or a polyester-based film.

[0080] (Dielectric properties) The resin film of the present embodiment is represented by the following formula (i), E 1 =√ε 1 ×Tanδ 1 ···(i) [Here, ε 1 represents the dielectric constant at 10 GHz measured by a split post dielectric resonator (SPDR) after conditioning for 24 hours under the constant temperature and humidity conditions (normal state) of 23°C and 50% RH, and Tanδ 1 represents the dielectric tangent at 10 GHz measured by SPDR after conditioning for 24 hours under the constant temperature and humidity conditions of 23°C and 50% RH. Note that "√ε 1 " means the square root of ε 1 .] The index E 1 value calculated based on the above shows the dielectric properties at 10 GHz after conditioning for 24 hours under the constant temperature and humidity conditions of 23°C and 50% RH, and is preferably 0.010 or less, more preferably 0.009 or less, and even more preferably 0.008 or less. When the E 1 value exceeds the above upper limit, for example, when used in a circuit board such as an FPC, inconveniences such as electrical signal loss on the high-frequency signal transmission path are likely to occur.

[0081] (Dielectric constant) The resin film of the present embodiment has a dielectric constant (ε 1is preferably 3.2 or less, more preferably 3.0 or less. If this dielectric constant exceeds 3.2, inconveniences such as loss of electrical signals on the transmission path of high-frequency signals are likely to occur when used in a circuit board such as an FPC.

[0082] (Dielectric tangent) In addition, for the resin film of the present embodiment, in order to reduce the loss of electrical signals when used in a circuit board such as an FPC, the dielectric tangent (Tanδ) at 10 GHz after humidity conditioning for 24 hours under constant temperature and humidity conditions of 23°C and 50% RH 1 is preferably less than 0.005, more preferably 0.004 or less. If this dielectric tangent is 0.005 or more, inconveniences such as loss of electrical signals on the transmission path of high-frequency signals are likely to occur when used in a circuit board such as an FPC.

[0083] (Moisture absorption dependency) For the resin film of the present embodiment, in order to reduce the loss of electrical signals and ensure impedance matching during drying and wetting when used in a circuit board such as an FPC, the following formula (ii), E 2 =√ε 2 ×Tanδ 2 ···(ii) [Here, ε 2 represents the dielectric constant at 10 GHz measured by SPDR after absorbing water for 24 hours at 23°C, and Tanδ 2 represents the dielectric tangent at 10 GHz measured by SPDR after absorbing water for 24 hours at 23°C. Note that "√ε 2 " means the square root of ε 2 .] E, which is an index indicating the dielectric characteristics at 10 GHz after absorbing water for 24 hours at 23°C calculated based on this, 2 In terms of the value, the ratio (E 1 / E 2 ) of the E 2 value calculated based on the above formula (i) to the E 1 value is in the range of 3.0 to 1.0, preferably in the range of 2.5 to 1.0, more preferably in the range of 2.2 to 1.0. E 2 / E 1 However, when it exceeds the above upper limit, for example, when used in a circuit board such as an FPC, it will cause an increase in the dielectric constant and dielectric tangent during wetting, and it is likely to cause inconveniences such as electrical signal loss on the high-frequency signal transmission path.

[0084] (Moisture absorption rate) In addition, in order to reduce the influence of humidity when the resin film of the present embodiment is used in a circuit board such as an FPC, the moisture absorption rate of the resin film is preferably 0.5% by weight or less, more preferably less than 0.3% by weight. Here, the "moisture absorption rate" means the moisture absorption rate after 24 hours or more under the constant temperature and humidity conditions of 23°C and 50% RH (the same meaning in this specification). When the moisture absorption rate of the resin film exceeds 0.5% by weight, for example, when used in a circuit board such as an FPC, it is likely to be affected by humidity, and inconveniences such as fluctuations in the transmission speed of high-frequency signals are likely to occur. That is, when the moisture absorption rate of the resin film exceeds the above range, it is easy to absorb water with a high dielectric constant, which causes an increase in the dielectric constant and dielectric tangent, and inconveniences such as electrical signal loss on the high-frequency signal transmission path are likely to occur.

[0085] (Storage elastic modulus) The resin film of the present embodiment may have a temperature range of 40 to 250°C in which the storage elastic modulus decreases rapidly with an increase in temperature. Such characteristics of the resin film are considered to be factors that relieve internal stress during thermal compression bonding and maintain dimensional stability after circuit processing. The resin film preferably has a storage elastic modulus at the upper limit temperature of the temperature range of 5×10 7 [Pa] or less. By setting such a storage elastic modulus, even if it is the upper limit of the above temperature range, thermal compression bonding at 250°C or lower is possible, ensuring adhesion and suppressing dimensional changes after circuit processing. Note that since the resin film of the present embodiment has high thermal expansibility but low elasticity, even if the CTE exceeds 30 ppm / K, the internal stress generated during lamination can be relieved.

[0086] (Glass transition temperature) The resin film of this embodiment preferably has a glass transition temperature (Tg) of 250°C or lower, more preferably in the range of 40°C or higher and 200°C or lower. When the Tg of the resin film is 250°C or lower, thermocompression bonding at a low temperature becomes possible, so that internal stress generated during lamination can be relaxed and dimensional changes after circuit processing can be suppressed. If the Tg of the resin film exceeds 250°C, the bonding temperature becomes high, and there is a risk of impairing dimensional stability after circuit processing.

[0087] (Thickness) The resin film of this embodiment preferably has a thickness in the range of, for example, 5 μm or more and 125 μm or less, more preferably in the range of 8 μm or more and 100 μm or less. If the thickness of the resin film is less than 5 μm, there is a risk of problems such as wrinkles occurring during conveyance in the manufacture of the resin film, etc. On the other hand, if the thickness of the resin film exceeds 125 μm, there is a risk of reduced productivity of the resin film.

[0088] [Laminated body] The laminated body according to an embodiment of the present invention has a base material and an adhesive layer laminated on at least one surface of this base material, and the adhesive layer is made of the above resin film. Note that the laminated body may include any layer other than the above. Examples of the base material in the laminated body include base materials of inorganic materials such as copper foil and glass plate, and base materials of resin materials such as polyimide-based film, polyamide-based film, and polyester-based film. Preferred embodiments of the laminated body include a coverlay film, a copper foil with resin, etc.

[0089] [Coverlay film] A coverlay film, which is one embodiment of the laminated body, has a coverlay film material layer as a base material and an adhesive layer laminated on one surface of the coverlay film material layer, and the adhesive layer is made of the above resin film. Note that the coverlay film may include any layer other than the above.

[0090] The material of the coverlay film material layer is not particularly limited. For example, polyimide-based films such as polyimide, polyetherimide, and polyamideimide, polyamide-based films, polyester-based films, etc. can be used. Among these, it is preferable to use a polyimide-based film having excellent heat resistance. In addition, the coverlay film material can also contain a black pigment in order to effectively exhibit light shielding properties, concealment properties, design properties, etc., and can contain optional components such as a matte pigment that suppresses the gloss of the surface within a range that does not impair the effect of improving dielectric properties.

[0091] The thickness of the coverlay film material layer is not particularly limited, but for example, a range of 5 μm or more and 100 μm or less is preferable. Also, the thickness of the adhesive layer is not particularly limited, but for example, a range of 10 μm or more and 75 μm or less is preferable.

[0092] The coverlay film of the present embodiment can be manufactured by the methods exemplified below. First, as a first method, after applying a varnish-like polyimide composition containing a solvent to one side of the coverlay film material layer, it is dried at a temperature of, for example, 80 to 180 °C to form an adhesive layer, whereby a coverlay film having a coverlay film material layer and an adhesive layer can be formed.

[0093] Also, as a second method, a varnish-like polyimide composition containing a solvent is applied onto an arbitrary base material, dried at a temperature of, for example, 80 to 180 °C, and then peeled off to form an adhesive film for the adhesive layer. This adhesive film is thermocompression bonded to the coverlay film material layer at a temperature of, for example, 60 to 220 °C to form a coverlay film.

[0094] [Copper foil with resin] The copper foil with resin, which is another aspect of the laminate, is obtained by laminating an adhesive layer on at least one side of a copper foil as a base material, and the adhesive layer is made of the above resin film. Note that the copper foil with resin of the present embodiment may contain any layer other than the above.

[0095] The thickness of the adhesive layer in the copper foil with resin is preferably in the range of, for example, 2 to 125 μm, more preferably in the range of 2 to 100 μm. If the thickness of the adhesive layer is less than the above lower limit value, problems such as insufficient adhesiveness may occur. On the other hand, if the thickness of the adhesive layer exceeds the above upper limit value, problems such as a decrease in dimensional stability may occur. Further, from the viewpoints of reducing the dielectric constant and the dielectric tangent, it is preferable that the thickness of the adhesive layer is 3 μm or more.

[0096] The material of the copper foil in the copper foil with resin is preferably one mainly composed of copper or a copper alloy. The thickness of the copper foil is preferably 35 μm or less, more preferably in the range of 5 to 25 μm. From the viewpoints of production stability and handleability, the lower limit value of the thickness of the copper foil is preferably 5 μm. Note that the copper foil may be a rolled copper foil or an electrolytic copper foil. Also, commercially available copper foils can be used as the copper foil.

[0097] The copper foil with resin may be prepared, for example, by sputtering a metal on a resin film to form a seed layer and then forming a copper layer by, for example, copper plating, or by laminating a resin film and a copper foil by a method such as thermocompression bonding. Further, since an adhesive layer is formed on the copper foil, the copper foil with resin may be prepared by casting a coating solution of a polyimide composition, drying it to form a coating film, and then performing necessary heat treatment.

[0098] [Metal-clad laminate] (First aspect) The metal-clad laminate according to an embodiment of the present invention includes an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, and at least one layer of the insulating resin layer is made of the above resin film. Note that the metal-clad laminate of the present embodiment may include any other layers.

[0099] (Second aspect) The metal-clad laminate according to another embodiment of the present invention is a so-called three-layer metal-clad laminate including, for example, an insulating resin layer, an adhesive layer laminated on at least one surface of the insulating resin layer, and a metal layer laminated on the insulating resin layer via the adhesive layer. The adhesive layer is made of the resin film. The three-layer metal-clad laminate may include any layer other than the above. In the three-layer metal-clad laminate, the adhesive layer may be provided on one or both surfaces of the insulating resin layer, and the metal layer may be provided on one or both surfaces of the insulating resin layer via the adhesive layer. That is, the three-layer metal-clad laminate may be a single-sided metal-clad laminate or a double-sided metal-clad laminate. By performing wiring circuit processing such as etching the metal layer of the three-layer metal-clad laminate, a single-sided FPC or a double-sided FPC can be manufactured.

[0100] The insulating resin layer in the three-layer metal-clad laminate is not particularly limited as long as it is composed of a resin having electrical insulation properties. Examples thereof include polyimide, epoxy resin, phenolic resin, polyethylene, polypropylene, polytetrafluoroethylene, silicone, ETFE, etc. It is preferably composed of polyimide. The polyimide layer constituting the insulating resin layer may be a single layer or a plurality of layers, but preferably includes a non-thermoplastic polyimide layer.

[0101] The thickness of the insulating resin layer in the three-layer metal-clad laminate is preferably in the range of, for example, 1 to 125 μm, more preferably in the range of 5 to 100 μm. If the thickness of the insulating resin layer is less than the above lower limit value, problems such as insufficient electrical insulation may occur. On the other hand, if the thickness of the insulating resin layer exceeds the above upper limit value, problems such as warping of the metal-clad laminate are likely to occur.

[0102] The thickness of the adhesive layer in the three-layer metal-clad laminate is preferably in the range of, for example, 0.1 to 125 μm, more preferably in the range of 0.3 to 100 μm. In the three-layer metal-clad laminate of the present embodiment, if the thickness of the adhesive layer is less than the above lower limit value, problems such as insufficient adhesiveness may occur. On the other hand, if the thickness of the adhesive layer exceeds the above upper limit value, problems such as a decrease in dimensional stability may occur. Further, from the viewpoint of reducing the dielectric constant and dielectric tangent of the entire insulating layer, which is a laminate of the insulating resin layer and the adhesive layer, the thickness of the adhesive layer is preferably 3 μm or more.

[0103] Also, the ratio of the thickness of the insulating resin layer to the thickness of the adhesive layer (thickness of the insulating resin layer / thickness of the adhesive layer) is preferably in the range of, for example, 0.1 to 3.0, more preferably in the range of 0.15 to 2.0. By setting such a ratio, warping of the three-layer metal-clad laminate can be suppressed. Further, the insulating resin layer may contain a filler as needed. Examples of the filler include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, metal salts of organic phosphinic acids, and the like. These can be used alone or in combination of two or more.

[0104] [Circuit Board] The circuit board according to the embodiment of the present invention is formed by wiring the metal layer of the metal-clad laminate of any of the above embodiments. By processing one or more metal layers of the metal-clad laminate into a pattern by a conventional method to form a wiring layer (conductor circuit layer), a circuit board such as an FPC can be manufactured. Note that the circuit board may include a coverlay film that covers the wiring layer.

Examples

[0105] Examples are shown below to more specifically explain the features of the present invention. However, the scope of the present invention is not limited to the examples. In the following examples, unless otherwise specified, various measurements and evaluations are as follows.

[0106] [Method for Measuring Amine Value] Weigh approximately 2 g of the dimer diamine composition into a 200 - 250 mL Erlenmeyer flask, use phenolphthalein as an indicator, and add dropwise a 0.1 mol / L ethanolic potassium hydroxide solution until the solution shows a faint pink color to perform neutralization. Then dissolve it in approximately 100 mL of butanol. Add 3 - 7 drops of phenolphthalein solution thereto, and titrate with a 0.1 mol / L ethanolic potassium hydroxide solution while stirring until the sample solution turns to a faint pink color. Add 5 drops of bromophenol blue solution thereto, and titrate with a 0.2 mol / L hydrochloric acid / isopropanol solution while stirring until the sample solution turns yellow. The amine value is calculated by the following formula (1). Amine value ={(V 2 × C 2 ) - (V 1 × C 1 )}× M KOH / m ···(1) Here, the amine value is a value expressed in mg - KOH / g, M KOH is the molecular weight of potassium hydroxide, 56.1. Also, V and C are the volume and concentration of the solution used for titration respectively, and the subscripts 1 and 2 represent a 0.1 mol / L ethanolic potassium hydroxide solution and a 0.2 mol / L hydrochloric acid / isopropanol solution respectively. Further, m is the sample weight expressed in grams.

[0107] [Measurement of Weight - Average Molecular Weight (Mw) of Polyimide] The weight - average molecular weight was measured by gel permeation chromatography (using HLC - 8220GPC manufactured by Tosoh Corporation). Polystyrene was used as a standard substance, and tetrahydrofuran (THF) was used as a developing solvent.

[0108] [Calculation of GPC and Area Percentage of Chromatogram] The GPC prepared a sample by diluting a 100 mg solution obtained by pretreating a 20 mg dimer diamine composition with 200 μL of acetic anhydride, 200 μL of pyridine, and 2 mL of THF with 10 mL of THF (containing 1000 ppm of cyclohexanone). The prepared sample was measured under the conditions of using a column: TSK-gel G2000HXL, G1000HXL, a flow rate: 1 mL / min, a column (oven) temperature: 40 °C, and an injection volume: 50 μL, using a product named HLC-8220GPC manufactured by Tosoh Corporation. Note that cyclohexanone was treated as a standard substance for correcting the elution time.

[0109] At this time, the peak top of the main peak of cyclohexanone was adjusted to be at a retention time of 27 minutes to 31 minutes, and the peak start to peak end of the main peak of the cyclohexanone was adjusted to be 2 minutes. The peak top of the main peak excluding the peak of cyclohexanone was adjusted to be at 18 minutes to 19 minutes, and the peak start to peak end of the main peak excluding the peak of cyclohexanone was adjusted to be from 2 minutes to 4 minutes and 30 seconds. Under these conditions, each of the components (a) to (c); (a) The component represented by the main peak; (b) The component represented by the GPC peak detected at a time later than the minimum value on the later time side of the retention time in the main peak; (c) The component represented by the GPC peak detected at a time earlier than the minimum value on the earlier time side of the retention time in the main peak; were detected.

[0110] [Evaluation of Dielectric Properties] Using a vector network analyzer (manufactured by Agilent Technologies, product name; Vector Network Analyzer E8363C) and an SPDR resonator, after leaving a polyimide film (cured polyimide film) standing for 24 hours under the conditions of a temperature of 23 °C and a humidity of 50%, the dielectric constant (ε 1 ) and the dielectric tangent (Tanδ 1) was measured. Also, after absorbing water at 23°C for 24 hours, the dielectric constant (ε 2 ) and the dielectric loss tangent (Tanδ 2 ) of the polyimide film (cured polyimide film) at a frequency of 10 GHz were measured.

[0111] [Measurement of moisture absorption rate] Two test pieces of polyimide film (width 4 cm × length 25 cm) were prepared and dried at 80°C for 1 hour. Immediately after drying, they were placed in a thermo-hygrostat chamber at 23°C / 50%RH and left standing for 24 hours or more. The moisture absorption rate was determined from the weight change before and after by the following formula. Moisture absorption rate (weight%) = [(weight after moisture absorption - weight after drying) / weight after drying] × 100

[0112] [Measurement of water absorption rate] Two test pieces of polyimide film (width 4 cm × length 25 cm) were prepared and dried at 80°C for 1 hour. Immediately after drying, they were placed in pure water at 23°C and left standing for 24 hours or more. The water absorption rate was determined from the weight change before and after by the following formula. Water absorption rate (weight%) = [(weight after water absorption - weight after drying) / weight after drying] × 100

[0113] [Glass transition temperature (Tg) and storage modulus] The glass transition temperature (Tg) and the storage modulus were measured for a polyimide film with a size of 5 mm × 20 mm using a dynamic viscoelasticity measuring device (DMA: manufactured by UBM Co., Ltd., product name; E4000F) at a heating rate of 4°C / min from 30°C to 400°C and a frequency of 11 Hz. The temperature at which the change in elastic modulus (tanδ) is maximum was taken as the glass transition temperature.

[0114] [Tensile modulus] The tensile modulus was measured using a tension tester (manufactured by Orientec Co., Ltd., product name Tensilon), with a test piece of width 12.7 mm × length 127 mm, and performing a tensile test at 50 mm / min to obtain the tensile modulus at 25°C.

[0115] [Solder heat resistance test (dry)] A printed circuit board with a circuit having a wiring width / wiring pitch (L / S) = 1 mm / 1 mm was prepared by circuit processing a polyimide copper-clad laminate (manufactured by Nippon Steel Chemical & Material Co., Ltd., product name: Espanex MB12-25-12UEG). The adhesive surface of the test piece was placed on the wiring of the printed circuit board and pressed under the conditions of a temperature of 160 °C, a pressure of 3.5 MPa, and a time of 60 minutes. After drying the test piece with copper foil at 105 °C, it was immersed in a solder bath set at each evaluation temperature for 10 seconds, and its adhesion state was observed to confirm the presence or absence of defects such as foaming, swelling, and peeling. The heat resistance is expressed as the upper limit temperature at which no defects occur. For example, "320 °C" means that when evaluated in a solder bath at 320 °C, no defects are observed.

[0116] [Solder Heat Resistance Test (Moisture Absorption)] A printed circuit board with a circuit having a wiring width / wiring pitch (L / S) = 1 mm / 1 mm was prepared by circuit processing a polyimide copper-clad laminate (manufactured by Nippon Steel Chemical & Material Co., Ltd., product name: Espanex MB12-25-12UEG). The adhesive surface of the test piece was placed on the wiring of the printed circuit board and pressed under the conditions of a temperature of 160 °C, a pressure of 3.5 MPa, and a time of 60 minutes. After leaving the test piece with copper foil at 40 °C and a relative humidity of 80% for 72 hours, it was immersed in a solder bath set at each evaluation temperature for 10 seconds, and its adhesion state was observed to confirm the presence or absence of defects such as foaming, swelling, and peeling. The heat resistance is expressed as the upper limit temperature at which no defects occur. For example, "260 °C" means that when evaluated in a solder bath at 260 °C, no defects are observed.

[0117] [Measurement of Peel Strength] The peel strength was determined using a tensilon tester (manufactured by Toyo Seiki Seisaku-sho, Ltd., product name: Strograph VE-10). The resin layer side of a 1-mm-wide sample (a laminate composed of a base material / resin layer) was fixed to an aluminum plate with double-sided tape, and the force when peeling the resin layer and the base material was obtained by peeling the base material in the 180° direction at a speed of 50 mm / min.

[0118] [Evaluation of Warpage] On a polyimide film material with a thickness of 25 μm (manufactured by Toray DuPont Co., Ltd., trade name: Kapton 100EN) or on a 12-μm copper foil, a polyimide solution was applied so that the thickness after drying would be 25 μm, and test pieces were prepared. In this state, it was placed so that the polyimide film material or the copper foil would be on the bottom surface, and the average of the heights of the warping at the four corners of the test piece was measured. A value of 5 mm or less was rated as "good", and a value exceeding 5 mm was rated as "unacceptable".

[0119] The abbreviations used in this example represent the following compounds. DDA1: A product obtained by distillation purification of PRIAMINE 1075 manufactured by Clariant Japan Ltd. (a component: 98.2 wt%, b component: 0%, c component: 1.9%, amine value: 206 mg KOH / g) DDA2: A product obtained by distillation purification of PRIAMINE 1075 manufactured by Clariant Japan Ltd. (a component: 99.2 wt%, b component: 0%, c component: 0.8%, amine value: 210 mg KOH / g) APB: 1,3-bis(3-aminophenoxy)benzene BTDA: 3,3',4,4'-benzophenonetetracarboxylic dianhydride N-12: Dodecanedioic acid dihydrazide NMP: N-methyl-2-pyrrolidone PX-200: A phosphate ester (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: PX-200, non-halogenated aromatic condensed phosphate ester, phosphorus content: 9.0%) PX-202: A phosphate ester (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: PX-202, non-halogenated aromatic condensed phosphate ester, phosphorus content: 8.1%) SR-3000: A phosphate ester (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: SR-3000, non-halogenated aromatic condensed phosphate ester, phosphorus content: 7.0%) DA-850: A phosphate ester (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DAIGUARD-850, non-halogenated aromatic condensed phosphate ester, phosphorus content: 16.0% or more) TPP (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: TPP, non-halogenated phosphate ester, phosphorus content: 9.5%) TCP (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: TCP, non-halogenated phosphate ester, phosphorus content: 8.4%) TXP (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: TXP, non-halogenated phosphate ester, phosphorus content: 7.6%) CR-733 (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: CR-733S, non-halogenated aromatic condensed phosphate ester, phosphorus content: 10.9%) CR-741 (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: CR-741, non-halogenated aromatic condensed phosphate ester, phosphorus content: 8.9%) CM-6R: Phosphorus-nitrogen compound (manufactured by Daiwa Chemical Industry Co., Ltd., trade name: Furane CM-6R, average particle size 5 μm) MC-6000: (manufactured by Nissan Chemical Industries, Ltd., trade name: MC-6000, non-halogenated melamine cyanurate) In the above DDA1 and DDA2, the “%” of the b component and the c component means the area percentage of the chromatogram in GPC measurement. Also, the molecular weights of DDA1 and DDA2 were calculated by the following formula (1). Molecular weight = 56.1×2×1000 / amine value ··· (1)

[0120] (Synthesis Example 1) Into a 1000 ml separable flask, 55.51 g of BTDA (0.1721 mol), 94.49 g of DDA1 (0.1735 mol), 210 g of NMP and 140 g of xylene were charged, and mixed well at 40 °C for 1 hour to prepare a polyamic acid solution. This polyamic acid solution was heated to 190 °C, heated and stirred for 10 hours, and 125 g of xylene was added to complete imidization to prepare a polyimide solution a (solid content concentration: 30% by weight, weight average molecular weight: 82,900, amine value: 206 mgKOH / g).

[0121] (Synthesis Examples 2-3) Polyimide solutions b-c were prepared in the same manner as in Synthesis Example 1, except that the raw material compositions shown in Table 1 were used.

[0122]

Table 1

[0123] (Production Example 1) To 169.49 g (50 g as solid content) of the polyimide solution a obtained in Synthesis Example 1, 2.7 g of N-12 (0.0105 mol; the primary amino group corresponds to 0.35 mol per 1 mol of the ketone group of BTDA) was blended, 6.0 g of NMP was added for dilution, and further stirred for 1 hour to obtain polyimide solution 1a.

[0124] The obtained polyimide solution 1a was applied to one side of a release PET film (manufactured by Toyama Film Co., Ltd., trade name; HY-S05, length × width × thickness = 200 mm × 300 mm × 25 μm), dried at 80°C for 15 minutes, and peeled off from the release PET film to prepare a polyimide film 1a' with a thickness of 25 μm. This polyimide film 1a' was pressed under the conditions of a temperature of 160°C, a pressure of 3.5 MPa, and a time of 60 minutes to obtain polyimide film 1a. The various evaluation results of polyimide film 1a are as follows. Dielectric constant (ε 1 ); 2.7, dielectric loss tangent (Tanδ 1 ); 0.0024, dielectric constant (ε 2 ); 2.7, dielectric loss tangent (Tanδ 2 ); 0.0034, moisture absorption rate; 0.07%, water absorption rate; 0.6%, Tg; 54°C, storage modulus at 200°C; 5.0×10 6 Pa, tensile modulus; 0.7 GPa, solder heat resistance (dry); 280°C, solder heat resistance (moisture absorption); 260°C, peel strength; 1.0 kN / m or more

[0125] (Production Examples 2, 3) Polyimide solutions 1b and 1c and polyimide films 1b and 1c were obtained in the same manner as in Production Example 1, except that polyimide solutions b and c were used instead of polyimide solution a. The various evaluation results of polyimide films 1b and 1c are as follows. <Polyimide Film 1b> Dielectric constant (ε 1 ); 2.7, dielectric loss tangent (Tanδ 1 ); 0.0024, dielectric constant (ε2 ); 2.7, Dielectric loss tangent (Tanδ 2 ); 0.0034, Moisture absorption rate; 0.07%, Water absorption rate; 0.2%, Tg; 54°C, Storage modulus at 200°C; Not measured, Tensile modulus; 0.7 GPa <Polyimide film 1c> Dielectric constant (ε 1 ); 2.9, Dielectric loss tangent (Tanδ 1 ); 0.0028, Dielectric constant (ε 2 ); 2.9, Dielectric loss tangent (Tanδ 2 ); 0.0052, Moisture absorption rate; 0.17%, Water absorption rate; 0.7%, Tg; 106°C, Storage modulus at 200°C; Less than 1.0×10 6 Pa, Tensile modulus; 1.4 GPa

[0126] [Example 1] To the polyimide solution 1a (100 parts by weight as solid content) obtained in Preparation Example 1, 10 parts by weight of SR-3000 was added to obtain a polyimide composition 1. The obtained polyimide composition 1 was applied to one side of a release PET film and dried at 80°C for 15 minutes and then peeled off from the release PET film to prepare a polyimide film 1' with a thickness of 25 μm. This polyimide film 1' was heated in an oven at 160°C for 2 hours to obtain a polyimide film 1. The various evaluation results of the polyimide film 1 are as follows. Dielectric constant (ε 1 ); 2.6, Dielectric loss tangent (Tanδ 1 ); 0.0022

[0127] [Examples 2 to 16] Each component was blended at the ratio (parts by weight) shown in Table 2, and in the same manner as in Example 1, polyimide compositions 2 to 16 were obtained. Note that "DDA composition" in Table 2 means a dimer diamine composition (the same applies in Table 3).

[0128]

Table 2

[0129] Using the obtained polyimide compositions 2 to 16, polyimide films 2 to 16 were prepared in the same manner as in Example 1. The various evaluation results of the polyimide films 2 to 16 are as follows. <Polyimide Film 2> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0022, Tensile modulus of elasticity; 0.7 GPa, Peel strength; 1.4 kN / m <Polyimide Film 3> Dielectric constant (ε 1 ); 2.6, Dissipation factor (Tanδ 1 ); 0.0020, Dielectric constant (ε 2 ); 2.6, Dissipation factor (Tanδ 2 ); 0.0021, Water absorption; 0.1%, Tg; 54 °C, Tensile modulus of elasticity; 0.7 GPa, Peel strength; 1.4 kN / m <Polyimide Film 4> Dielectric constant (ε 1 ); 2.6, Dissipation factor (Tanδ 1 ); 0.0024, Tensile modulus of elasticity; 0.5 GPa, Peel strength; 1.5 kN / m <Polyimide Film 5> Dielectric constant (ε 1 ); 2.6, Dissipation factor (Tanδ 1 ); 0.0022, Tensile modulus of elasticity; 0.7 GPa <Polyimide Film 6> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0023, Tensile modulus of elasticity; 0.1 GPa, Peel strength; 1.6 kN / m <Polyimide Film 7> Dielectric constant (ε 1 ); 2.6, Dissipation factor (Tanδ 1 ); 0.0022, Water absorption; 0.29%, Tensile modulus of elasticity; 0.5 GPa, Peel strength; 1.6 kN / m <Polyimide Film 8> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1); Water absorption rate: 0.54%, Tensile modulus of elasticity: 0.4 GPa, Peel strength: 1.3 kN / m <Polyimide film 9> Dielectric constant (ε 1 ); 2.6, Dissipation factor (Tanδ 1 ); Water absorption rate: 0.91%, Tensile modulus of elasticity: 0.3 GPa, Peel strength: 1.4 kN / m <Polyimide film 10> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); Water absorption rate: 0.0020, Peel strength: 0.7 kN / m <Polyimide film 11> Dielectric constant (ε 1 ); 2.6, Dissipation factor (Tanδ 1 ); 0.0022 <Polyimide film 12> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0021 <Polyimide film 13> Dielectric constant (ε 1 ); 2.6, Dissipation factor (Tanδ 1 ); 0.0020 <Polyimide film 14> Dielectric constant (ε 1 ); 2.8, Dissipation factor (Tanδ 1 ); 0.0027 <Polyimide film 15> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0026 <Polyimide film 16> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0025

[0130] [Reference Examples 1 to 18] The components were blended at the ratios (parts by weight) shown in Table 3, and in the same manner as in Example 1, polyimide compositions 17 to 34 were obtained.

[0131]

Table 3

[0132] Using the obtained polyimide compositions 17 to 34, polyimide films 17 to 34 were prepared in the same manner as in Example 1. The various evaluation results of the polyimide films 17 to 34 are as follows. <Polyimide Film 17> Dielectric constant (ε 1 ); 2.7, Dielectric tangent (Tanδ 1 ); 0.0024, Dielectric constant (ε 2 ); 2.7, Dielectric tangent (Tanδ 2 ); 0.0034, Water absorption rate; 0.2%, Tensile modulus of elasticity; 0.9 GPa, Peel strength; 1.2 kN / m <Polyimide Film 18> Dielectric constant (ε 1 ); 2.9, Dielectric tangent (Tanδ 1 ); 0.0025, Tensile modulus of elasticity; 0.6 GPa, Peel strength; 0.4 kN / m <Polyimide Film 19> Dielectric constant (ε 1 ); 2.6, Dielectric tangent (Tanδ 1 ); 0.0031, Tensile modulus of elasticity; 0.3 GPa <Polyimide Film 20> Dielectric constant (ε 1 ); 2.8, Dielectric tangent (Tanδ 1 ); 0.0041, Tensile modulus of elasticity; 0.1 GPa <Polyimide Film 21> Dielectric constant (ε 1 ); 2.6, Dielectric tangent (Tanδ 1 ); 0.0028, Tensile modulus of elasticity; 0.2 GPa <Polyimide Film 22> Dielectric constant (ε 1 ); 2.8, Dielectric tangent (Tanδ 1 ); 0.0033, Tensile modulus of elasticity; 0.0 GPa <Polyimide Film 23> Dielectric constant (ε 1 ); 2.7, Dielectric tangent (Tanδ1 ); 0.0026, Tensile modulus of elasticity; 0.3 GPa <Polyimide film 24> Dielectric constant (ε 1 ); 2.8, Dissipation factor (Tanδ 1 ); 0.0028, Tensile modulus of elasticity; 0.0 GPa <Polyimide film 25> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0028, Tensile modulus of elasticity; 0.3 GPa <Polyimide film 26> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0034, Tensile modulus of elasticity; 0.1 GPa <Polyimide film 27> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0027, Tensile modulus of elasticity; 0.4 GPa <Polyimide film 28> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0031, Tensile modulus of elasticity; 0.2 GPa <Polyimide film 29> Dielectric constant (ε 1 ); 2.7, Dissipation factor (Tanδ 1 ); 0.0031 <Polyimide film 30> Dielectric constant (ε 1 ); 2.6, Dissipation factor (Tanδ 1 ); 0.0027 <Polyimide film 31> Dielectric constant (ε 1 ); 2.8, Dissipation factor (Tanδ 1 ); 0.0035 <Polyimide film 32> Dielectric constant (ε 1 ); 2.9, Dissipation factor (Tanδ 1 ); 0.0031 <Polyimide film 33> Dielectric constant (ε 1); 3.0, Dielectric Dissipation Factor (Tanδ 1 ); 0.0140 <Polyimide Film 34> Dielectric Constant (ε 1 ); 2.6, Dielectric Dissipation Factor (Tanδ 1 ); 0.0021

[0133] Summarizing the above results, the evaluation results of the dielectric properties of Polyimide Films 1 to 34 are shown in Tables 4 and 5.

[0134]

Table 4

[0135]

Table 5

[0136] [Example 17] Each component was blended at the ratio (parts by weight) described in Table 2, and in the same manner as in Example 1, Polyimide Composition 2 prepared was coated on one side of Polyimide Film Material P1 (manufactured by Toray DuPont Co., Ltd., trade name; Kapton 50EN, dielectric constant at a frequency of 10 GHz = 3.6, dielectric dissipation factor at a frequency of 10 GHz = 0.0084, length × width × thickness = 200 mm × 300 mm × 12 μm), and dried at 80°C for 15 minutes to obtain Coverlay Film 17 with an adhesive layer thickness of 25 μm. The warp state of the obtained Coverlay Film 17 was "good".

[0137] [Example 18] The release PET film was laminated so as to contact the adhesive layer side of the cover leaf film 17, and pressure bonding was performed at a temperature of 160 ° C, a pressure of 0.8 MPa, and for 2 minutes using a vacuum laminator. Then, the polyimide composition 2 was applied to the polyimide film material P1 side of the cover leaf film 17 with the release PET film pressure-bonded so that the thickness after drying became 25 μm, and drying was performed at 80 ° C for 15 minutes. Then, it was laminated so that the release PET film contacted the surface on which the polyimide composition 2 was applied and dried, and pressure bonding was performed at a temperature of 160 ° C, a pressure of 0.8 MPa, and for 2 minutes using a vacuum laminator to obtain a laminate 18 having adhesive layers on both sides of the polyimide film material P1.

[0138] [Example 19] The polyimide composition 2 was applied to one side of an electrolytic copper foil having a thickness of 12 μm and dried at 80 ° C for 15 minutes to obtain a copper foil 19 with resin having an adhesive layer thickness of 25 μm. The warping state of the obtained copper foil 19 with resin was "good".

[0139] [Example 20] The polyimide composition 2 was applied to one side of an electrolytic copper foil having a thickness of 12 μm and dried at 80 ° C for 30 minutes to obtain a copper foil 20 with resin having an adhesive layer thickness of 50 μm. The warping state of the obtained copper foil 20 with resin was "good".

[0140] [Example 21] The polyimide composition 2 was further applied to the surface of the adhesive layer of the copper foil 19 with resin and dried at 80 ° C for 30 minutes to obtain a copper foil 21 with resin having a total adhesive layer thickness of 100 μm. The warping state of the obtained copper foil 21 with resin was "good".

[0141] [Example 22] The polyimide composition 2 was applied to one side of the release PET film and dried at 80 ° C for 30 minutes, and by peeling from the release PET film, a polyimide film 35 having a thickness of 50 μm was obtained.

[0142] [Example 23] On an electrolytic copper foil with a thickness of 12 μm, a polyimide film 2, a polyimide film material P2 (manufactured by DuPont, trade name: Kapton 100-EN, thickness 25 μm, dielectric constant at a frequency of 10 GHz = 3.6, dielectric tangent at a frequency of 10 GHz = 0.0084), a polyimide film 2, and an electrolytic copper foil with a thickness of 12 μm were sequentially laminated. After crimping at a temperature of 160 °C, a pressure of 0.8 MPa for 2 minutes using a vacuum laminator, the temperature was raised from room temperature to 160 °C and heat-treated at 160 °C for 4 hours to obtain a copper-clad laminate 23.

[0143] [Example 24] On an electrolytic copper foil with a thickness of 12 μm, it was laminated so that the adhesive layer side of the coverlay film 17 was in contact with the copper foil. After crimping at a temperature of 160 °C, a pressure of 0.8 MPa for 2 minutes using a vacuum laminator, the temperature was raised from room temperature to 160 °C and heat-treated at 160 °C for 2 hours to obtain a copper-clad laminate 24.

[0144] [Example 25] On a rolled copper foil with a thickness of 12 μm, a polyimide film 2 was laminated, and it was laminated so that the polyimide film material P1 side of the coverlay film 17 was in contact with the polyimide film 2. Further, a rolled copper foil with a thickness of 12 μm was sequentially laminated on the adhesive layer side of the coverlay film 17. After crimping at a temperature of 160 °C, a pressure of 0.8 MPa for 2 minutes using a vacuum laminator, the temperature was raised from room temperature to 160 °C and heat-treated at 160 °C for 2 hours to obtain a copper-clad laminate 25.

[0145] [Example 26] Two resin-coated copper foils 19 were prepared, and a polyimide film material P3 (manufactured by DuPont, trade name: Kapton 200-EN, thickness 50 μm, dielectric constant at a frequency of 10 GHz = 3.6, dielectric tangent at a frequency of 10 GHz = 0.0084) was laminated so as to be in contact with the adhesive layer sides of the two resin-coated copper foils 19. After crimping at a temperature of 160 °C, a pressure of 0.8 MPa for 5 minutes using a vacuum laminator, the temperature was raised from room temperature to 160 °C and heat-treated at 160 °C for 4 hours to obtain a copper-clad laminate 26.

[0146] [Example 27] The polyimide composition 2 was applied to the surface on the resin layer side of a single-sided copper-clad laminate M1 (manufactured by Nippon Steel Chemical & Material Co., Ltd., trade name: Espanex MC12-25-00UEM, length × width × thickness = 200 mm × 300 mm × 25 μm), and dried at 80°C for 30 minutes to obtain an adhesive-coated copper-clad laminate 27 with an adhesive layer thickness of 50 μm. On the adhesive layer side of the adhesive-coated copper-clad laminate 27, the surface on the resin layer side of the single-sided copper-clad laminate M1 was laminated so as to be in contact, and it was pressure-bonded using a small precision press at a temperature of 160°C, a pressure of 4.0 MPa, and for 120 minutes to obtain a copper-clad laminate 27.

[0147] [Example 28] A polyimide film 2 was laminated on the resin layer side of the single-sided copper-clad laminate M1, and further laminated thereon such that the resin layer side of the single-sided copper-clad laminate M1 was in contact with the polyimide film 2, and it was pressure-bonded using a small precision press at a temperature of 160°C, a pressure of 4.0 MPa, and for 120 minutes to obtain a copper-clad laminate 28.

[0148] [Example 29] The polyimide composition 2 was applied to one side of a release PET film and dried at 80°C for 15 minutes. By peeling the adhesive layer from the release PET film, a polyimide film 36 with a thickness of 15 μm was obtained.

[0149] [Example 30] A double-sided copper-clad laminate M2 (manufactured by Nippon Steel Chemical & Material Co., Ltd., trade name: Espanex MB12-25-00UEG) was prepared, and circuit processing by etching was performed on the copper foil on one side to obtain a wiring board 1A having a conductor circuit layer formed.

[0150] The copper foil on one side of the double-sided copper-clad laminate M2 was removed by etching to obtain a copper-clad laminate 1B.

[0151] A polyimide film 2 was sandwiched between the surface on the conductor circuit layer side of the wiring board 1A and the surface on the resin layer side of the copper-clad laminate 1B, and in the laminated state, it was thermocompression-bonded at a temperature of 160°C, a pressure of 4.0 MPa, and for 120 minutes to obtain a multilayer circuit board 30.

[0152] [Example 31] A copper-clad laminate 1C was prepared using a liquid crystal polymer film (manufactured by Kuraray Co., Ltd., trade name: CT-Z, thickness: 50 μm, CTE: 18 ppm / K, heat distortion temperature: 300 °C, dielectric constant at a frequency of 10 GHz = 3.40, dielectric tangent at a frequency of 10 GHz = 0.0022) as an insulating substrate, and electrolytic copper foils with a thickness of 18 μm were provided on both sides thereof. Circuit processing by etching was performed on the copper foil on one side to obtain a wiring board 1C having a conductor circuit layer formed thereon.

[0153] The copper foil on one side of the copper-clad laminate 1C was removed by etching to obtain a copper-clad laminate 1D.

[0154] A polyimide film 2 was sandwiched between the surface on the conductor circuit layer side of the wiring board 1C and the surface on the insulating substrate layer side of the copper-clad laminate 1D, and heat pressure bonding was performed at a temperature of 160 °C, a pressure of 4.0 MPa, and for 120 minutes in a laminated state to obtain a multilayer circuit board 31.

[0155] As described above, the embodiments of the present invention have been described in detail for illustrative purposes. However, the present invention is not limited to the above embodiments, and various modifications are possible.

Claims

1. The following components (A) and (B): (A) a polyimide obtained by reacting a tetracarboxylic anhydride component with a diamine component containing 40 mol % or more of a dimer diamine composition mainly composed of a dimer diamine in which two terminal carboxylic acid groups of a dimer acid are substituted with primary aminomethyl groups or amino groups, based on the total diamine component; and (B) an aromatic condensed phosphate ester, a weight ratio of the component (B) to the component (A) is within a range of 0.05 to 0.7, and a weight ratio of phosphorus derived from the component (B) to a dimer diamine composition in the component (A) is within a range of 0.01 to 0.

15.

2. 2. The polyimide composition according to claim 1, wherein a weight ratio of said component (B) to said component (A) is within a range of 0.2 to 0.

5.

3. 3. The polyimide composition according to claim 1, wherein a weight ratio of phosphorus derived from the component (B) to the component (A) is within a range of 0.01 to 0.

1.

4. 4. The polyimide composition according to claim 1, further comprising an amino compound having at least two primary amino groups as functional groups.

5. A resin film including a polyimide layer, The polyimide layer comprises the following components (A) and (B); (A) a polyimide obtained by reacting a tetracarboxylic anhydride component with a diamine component containing 40 mol % or more of a dimer diamine composition mainly composed of a dimer diamine in which two terminal carboxylic acid groups of a dimer acid are substituted with primary aminomethyl groups or amino groups, based on the total diamine component; and (B) an aromatic condensed phosphate ester, a weight ratio of the component (B) to the component (A) is within a range of 0.05 to 0.7, and a weight ratio of phosphorus derived from the component (B) to a dimer diamine composition in the component (A) is within a range of 0.01 to 0.

15.

6. A laminate having a substrate and an adhesive layer laminated on at least one surface of the substrate, A laminate comprising the resin film according to claim 5, wherein the adhesive layer is made of the resin film.

7. A coverlay film having a coverlay film material layer and an adhesive layer laminated on the coverlay film material layer, A coverlay film, wherein the adhesive layer is made of the resin film according to claim 5 .

8. A resin-coated copper foil in which an adhesive layer and a copper foil are laminated, A resin-coated copper foil, wherein the adhesive layer is made of the resin film according to claim 5.

9. A metal-clad laminate having an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, A metal-clad laminate, wherein at least one of the insulating resin layers is made of the resin film according to claim 5.

10. A circuit board obtained by wiring the metal layer of the metal-clad laminate according to claim 9.

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