KR20210038331A - Polyimide film, metal clad laminate and circuit board - Google Patents

Abstract

The present invention provides a polyimide film capable of achieving both low dielectric loss tangent and excellent long-term heat-resistant adhesion, and which are not susceptible to decrease in adhesion to a metal layer even when repeatedly exposed to a high-temperature environment. The polyimide film has a non-thermoplastic polyimide layer and a thermoplastic polyimide layer, and the polyimide film satisfies the following: (i) the coefficient of thermal expansion is within the range of 10 ppm/K to 30 ppm/K; (ii) the oxygen transmission rate is 5.5 x 10^-14 mol/(㎡·s·㎩) or less; and (iii) the ratio of monomer residues having a biphenyl skeleton to all monomer residues derived from all monomer components constituting the non-thermoplastic polyimide and the thermoplastic polyimide is 50 mol% or more.

Description

Polyimide film, metal clad laminate, and circuit board TECHNICAL FIELD [POLYIMIDE FILM, METAL CLAD LAMINATE AND CIRCUIT BOARD}

The present invention relates to a polyimide film, a metal-clad laminate, and a circuit board.

Polyimide resins have features such as high insulation, dimensional stability, ease of molding, and light weight, and are therefore widely used in electronic, electrical equipment, and electronic parts as materials such as circuit boards. In particular, in recent years, along with the high performance and high functionality of electric and electronic devices, high-speed transmission of information is required, and a response to high-speed transmission is also required for parts and members used therein. For polyimide materials used for such purposes, attempts have been made to achieve low dielectric constant and low dielectric tangent so that they have electrical properties corresponding to high-speed transmission.

Most of the conventional techniques related to low dielectric constant and low dielectric tangent of polyimide materials are multilayered with resins (fluorine-based resins, liquid crystal polymers, etc.) with low dielectric constant and low dielectric tangent, and blending of fillers with low dielectric constant and low dielectric tangent. The main ones were complexing with the same heterogeneous material, porosity, and introduction of ester structures. However, there is a problem in that the processability is deteriorated with respect to complexation and porosity, and the introduction of an ester structure has a problem in that it cannot be used in a large amount because the film strength decreases.

In addition, in Patent Documents 1 and 2, a polyimide film that can be applied to a high frequency circuit board is proposed by devising a composition of a raw material monomer of a polyimide, thereby improving dielectric properties.

On the other hand, in recent years, it is also assumed that the circuit board is used in an environment exceeding 150°C. For example, flexible printed circuits (FPCs) used in vehicle-mounted electronic devices may be repeatedly exposed to a high temperature environment of about 150°C.

In addition, in devices other than on-vehicle electronic devices, for example, notebook computers and supercomputers with CPUs (Central Processing Unit) capable of performing high-speed processing, flexible printed circuit boards are used to further reduce size and weight. The work of becoming is increasing. Also in such a device, the flexible printed circuit board is repeatedly exposed to a high-temperature environment by the heat emitted by the CPU. A typical factor of deterioration of the flexible printed circuit board due to use in a high-temperature environment is lifting or peeling of the wiring layer due to a decrease in adhesiveness between the wiring layer and the insulating resin layer.

From this background, in the future, it is expected that flexible printed circuit boards will need to achieve both low dielectric tangent and heat-resistant adhesiveness (maintaining the peel strength retention rate) in a high-temperature environment. It is thought that maintenance of heat-resistant adhesiveness will be required over a long period of time.

WO2017/159274 WO2018/061727

Accordingly, it is an object of the present invention to provide a polyimide film that achieves both low dielectric loss tangent and excellent long-term heat-resistant adhesiveness, and is unlikely to deteriorate adhesiveness with a metal layer even when repeatedly exposed to a high-temperature environment.

As a result of intensive research, the present inventors found that in the polyimide constituting the polyimide layer, by increasing the content ratio of the monomer residue having a biphenyl skeleton, low dielectric loss tangent of a polyimide film in which a plurality of polyimide layers are laminated The present invention was completed by finding that both excellent long-term heat-resistant adhesiveness can be achieved by suppressing the oxygen permeability and oxygen permeability.

That is, the polyimide film of the present invention comprises a non-thermoplastic polyimide layer comprising a non-thermoplastic polyimide, and a thermoplastic polyimide layer comprising a thermoplastic polyimide laminated on at least one side of the non-thermoplastic polyimide layer. To have.

The polyimide film of the present invention is characterized by satisfying the following conditions (i) to (iii).

(i) The thermal expansion coefficient is in the range of 10 to 30 ppm/K.

(ii) What has an oxygen permeability of 5.5×10 ^-14 mol/(m2·s·Pa) or less.

(iii) The ratio of the monomer residues having a biphenyl skeleton calculated by the following formula (1) to the total monomer residues derived from all the monomer components constituting the non-thermoplastic polyimide and the thermoplastic polyimide is 50 mol% What's more.

In the formula (1), M _i is the ratio of the monomer residues having a biphenyl skeleton among all monomer residues derived from all monomer components in the polyimide constituting the i-th polyimide layer (unit; Mol%), L _i is the thickness (unit: µm) of the polyimide layer of the i-th layer, L is the thickness (unit: µm) of the polyimide film, and n is an integer of 2 or more.

In addition to the conditions of (i) to (iii), the polyimide film of the present invention may also satisfy the following condition (iv).

(iv) Among all the monomer residues derived from all the monomer components in the thermoplastic polyimide, the proportion of the monomer residue having a biphenyl skeleton is 30 mol% or more.

The polyimide film of the present invention may have an overall thickness of 30 to 60 µm. In this case, the ratio T2/T1 of the total thickness T2 of the thermoplastic polyimide layer to the total thickness T1 of the polyimide film may be 0.17 or less.

The metal-clad laminate of the present invention is a metal-clad laminate comprising an insulating resin layer and a metal layer provided on at least one side of the insulating resin layer. And the metal-clad laminate of the present invention, wherein the insulating resin layer has a thermoplastic polyimide layer in contact with the surface of the metal layer and a non-thermoplastic polyimide layer indirectly laminated, and the polyimide film of any of the above. It is characterized by that.

The circuit board of the present invention is a circuit board including an insulating resin layer and a wiring layer provided on at least one side of the insulating resin layer. And the circuit board of the present invention is characterized in that the insulating resin layer has a thermoplastic polyimide layer in contact with the wiring layer and a non-thermoplastic polyimide layer indirectly laminated, and includes a polyimide film of any of the above. do.

In the polyimide film of the present invention, when the content of the monomer residue having a biphenyl skeleton is 50 mol% or more, oxygen permeability is suppressed, and low dielectric loss tangent and long-term heat resistance improvement are both achieved. Therefore, by using the polyimide film of the present invention as a circuit board material, a circuit board capable of responding to high-speed transmission and maintaining adhesion to the metal layer over a long period of time, even in a use environment repeatedly exposed to a high-temperature environment. Can provide.

1 is a schematic cross-sectional view showing a configuration of a polyimide film according to an embodiment of the present invention.
2 is a schematic cross-sectional view showing another configuration example of the polyimide film according to the embodiment of the present invention.

Next, an embodiment of the present invention will be described.

[Polyimide Film]

The polyimide film according to an embodiment of the present invention includes a non-thermoplastic polyimide layer containing a non-thermoplastic polyimide, and a thermoplastic polyimide containing a thermoplastic polyimide laminated on at least one side of the non-thermoplastic polyimide layer. It is a polyimide film having a mid layer. Here, "non-thermoplastic polyimide" means that the storage modulus at 30°C measured using a dynamic viscoelasticity measuring device (DMA) is 1.0×10 ⁹ Pa or more, and storage in a temperature range within the glass transition temperature +30°C. It means that the modulus of elasticity is 1.0×10 ⁸ Pa or more. "Thermoplastic polyimide" means that 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 in the temperature range within the glass transition temperature +30°C is 1.0. It means showing less than ^{x10 8 Pa.}

1 and 2 have shown a configuration example of a polyimide film according to the present embodiment. The polyimide film 100 shown in FIG. 1 is an aspect of a two-layer structure in which a thermoplastic polyimide layer 120A is laminated on one side of a non-thermoplastic polyimide layer 110. The polyimide film 101 shown in FIG. 2 has a three-layer structure in which a thermoplastic polyimide layer 120A is laminated on one side of the non-thermoplastic polyimide layer 110 and a thermoplastic polyimide layer 120B is laminated on the other side. It is an aspect of. In addition, the polyimide film of this embodiment is not limited to the laminated structure illustrated in Figs. 1 and 2, and may include, for example, four or more polyimide layers.

The resin component of the non-thermoplastic polyimide layer 110 preferably contains a non-thermoplastic polyimide, and the resin component of the thermoplastic polyimide layers 120A and 120B preferably contains a thermoplastic polyimide. When the polyimide films 100 and 101 and the metal foil are laminated to form a metal-clad laminate, the metal foil can be laminated on one side or both sides of the thermoplastic polyimide layers 120A and 120B.

In addition, both the non-thermoplastic polyimide and the thermoplastic polyimide contain an acid dianhydride residue and a diamine residue as "monomer residues". The "acid dianhydride residue" means a tetravalent group derived from a tetracarboxylic dianhydride, and the "diamine residue" means a divalent group derived from a diamine compound.

In the polyimide films 100 and 101 of the present embodiment, the non-thermoplastic polyimide layer 110 constitutes a polyimide layer having low thermal expansion, and the thermoplastic polyimide layers 120A and 120B are polyimide layers having high thermal expansion properties. Configure. The low thermal expansion polyimide layer refers to a polyimide layer having a thermal expansion coefficient (CTE) of preferably 1 ppm/K or more and 25 ppm/K or less, and more preferably 3 ppm/K or more and 25 ppm/K or less. In addition, the high thermal expansion polyimide layer has a CTE of preferably 35 ppm/K or more, more preferably 35 ppm/K or more and 80 ppm/K or less, and still more preferably 35 ppm/K or more and 70 ppm/K or less. It refers to the inner polyimide layer. A polyimide layer having a desired CTE can be obtained by appropriately changing the combination of the raw materials to be used, the thickness, and the drying and curing conditions.

The polyimide films 100 and 101 of the present embodiment satisfy the following conditions (i) to (iii).

(i) The thermal expansion coefficient is in the range of 10 to 30 ppm/K.

When the polyimide films 100 and 101 of the present embodiment are applied as an insulating resin layer of a circuit board, for example, in order to prevent the occurrence of warpage and decrease in dimensional stability, the coefficient of thermal expansion (CTE) of the entire film is It is important that) is in the range of 10 ppm/K or more and 30 ppm/K or less, preferably 10 ppm/K or more and 25 ppm/K or less, and more preferably 15 to 25 ppm/K. When the CTE is less than 10 ppm/K or exceeds 30 ppm/K, warpage occurs or dimensional stability is deteriorated.

(ii) What has an oxygen permeability of 5.5×10 ^-14 mol/(m2·s·Pa) or less.

By controlling the oxygen permeability of the polyimide films (100, 101) to 5.5 × 10 ^-14 mol/(m 2 ·s · Pa) or less, for example, in the case of applying as an insulating resin layer of a circuit board, repeated high temperature Even in an environment exposed to, the adhesion with the wiring layer is maintained over a long period of time, and excellent long-term heat resistance adhesion is obtained. When the oxygen permeability of the polyimide films (100, 101) exceeds 5.5×10 ^-14 mol/(m2·s·Pa), for example, it is applied as an insulating resin layer of a circuit board and repeatedly exposed to high temperatures. In this case, oxidation of the wiring layer proceeds due to oxygen passing through the insulating resin layer, and the adhesion between the wiring layer and the insulating resin layer is deteriorated.

(iii) Monomer residues having a biphenyl skeleton calculated by the following formula (1) with respect to all monomer residues derived from all monomer components constituting the non-thermoplastic polyimide and the thermoplastic polyimide (hereinafter referred to as ``biphenyl skeleton containing Residues" may be described) with a ratio of 50 mol% or more.

In the formula (1), M _i is the ratio (unit: mol%) of the total monomer residues derived from all monomer components in the polyimide constituting the i-th polyimide layer, the biphenyl skeleton-containing residue. ), L _i is the thickness (unit: µm) of the polyimide layer of the i-th layer, L is the thickness (unit: µm) of the polyimide film, and n is an integer of 2 or more.

Since the ratio of the biphenyl skeleton-containing residues calculated by formula (1) to all monomer residues derived from all monomer components of the polyimide constituting the polyimide films (100, 101) is 50 mol% or more, it is derived from a monomer. Due to the rigid structure of the polymer, an ordered structure is easily formed in the entire polymer, and the oxygen permeability is lowered, and the dielectric loss tangent can be lowered by suppressing the motion of the molecules. If the proportion of the biphenyl skeleton-containing residue is less than 50 mol%, the dielectric loss tangent does not sufficiently decrease. In addition, when the thickness of the polyimide film is made thin, the oxygen permeability is not sufficiently reduced. For this reason, when used for a circuit board, for example, long-term heat-resistant adhesiveness becomes insufficient, and adaptation to high-speed transmission becomes difficult. From this viewpoint, the ratio of the biphenyl skeleton-containing residue calculated by formula (1) is preferably 60 mol% or more, and more preferably 65 mol% or more. On the other hand, in order to maintain the physical properties required for a polyimide film that can be used as a circuit board material, the proportion of the biphenyl skeleton-containing residue calculated by formula (1) is preferably 80 mol% or less.

Here, the biphenyl skeleton is a skeleton in which two phenyl groups are single bonded, as shown in the following formula (a). Therefore, the biphenyl skeleton-containing residue includes, for example, a biphenyldiyl group and a biphenyltetrayl group. The aromatic ring contained in these residues may have an arbitrary substituent.

Representative examples of the biphenyldiyl group include those represented by the following formula (b). Representative examples of the biphenyltetrayl group include those represented by the following formula (c). In addition, in the biphenyldiyl group and the biphenyltetrayl group, the bonding hand in the aromatic ring is not limited to the positions shown in formulas (b) and (c), and as described above, to these residues The included aromatic ring may have an arbitrary substituent.

The biphenyl skeleton-containing residue has a structure derived from a raw material monomer, and may be derived from an acid dianhydride, or may be derived from a diamine compound.

Representative examples of acid dianhydride residues having a biphenyl skeleton include 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,3',3,4'-biphenyltetracarboxyl And residues derived from acid dianhydrides such as acid dianhydride and 4,4'-biphenol-bis (trimellitate anhydride). Among these, in particular, acid dianhydride residues derived from BPDA (hereinafter, also referred to as ``BPDA residues'') are preferable because they tend to form an ordered structure of the polymer, and can reduce the dielectric loss tangent or hygroscopicity by inhibiting the motion of the molecule. . Further, the BPDA residue can impart self-supporting properties of the gel film as a polyamic acid of the polyimide precursor.

Representative examples of diamine compounds having a biphenyl skeleton include diamine compounds having only two aromatic rings, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2' -Diethyl-4,4'-diaminobiphenyl (m-EB), 2,2'-diethoxy-4,4'-diaminobiphenyl (m-EOB), 2,2'-dipropoxy -4,4'-diaminobiphenyl (m-POB), 2,2'-di-n-propyl-4,4'-diaminobiphenyl (m-NPB), 2,2'-divinyl- 4,4'-diaminobiphenyl (VAB), 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl (TFMB), etc. Can be lifted. Since the residues derived from these diamine compounds have a rigid structure, they have an action of imparting an ordered structure to the entire polymer. By containing the residues derived from these diamine compounds, a polyimide having low oxygen permeability and low hygroscopicity can be obtained, and the moisture inside the molecular chain can be reduced, so that the dielectric loss tangent can be lowered.

It is preferable that the polyimide films 100 and 101 of the present embodiment further satisfy the following condition (iv) in addition to the conditions (i) to (iii).

(iv) Among all the monomer residues derived from all the monomer components in the thermoplastic polyimide, the ratio of the biphenyl skeleton-containing residue to 30 mol% or more.

Since the proportion of the biphenyl skeleton-containing residues among the total monomer residues constituting the thermoplastic polyimide is 30 mol% or more, the rigid structure derived from the monomer forms an ordered structure throughout the polymer, so it is thermoplastic, oxygen permeability and hygroscopicity This low, long-term heat-resistant adhesiveness is excellent, and a polyimide having a low dielectric loss tangent is obtained. In addition, in the case of having the thermoplastic polyimide layers 120A and 120B on both sides of the non-thermoplastic polyimide layer 110, any one of the thermoplastic polyimide layers 120A and 120B may satisfy the above condition (iv), It is preferable that both of the thermoplastic polyimide layers 120A and 120B satisfy the above condition (iv).

<Thickness>

The overall thickness T1 of the polyimide films 100 and 101 of the present embodiment can be set within a predetermined range depending on the purpose of use, and is preferably within a range of, for example, 30 to 60 μm, It is more preferably in the range of 35 to 50 µm. If the thickness T1 is less than the above lower limit, it becomes difficult to sufficiently lower the oxygen permeability, and there is a fear that the adhesion between the wiring layer and the insulating resin layer may deteriorate when repeatedly exposed to high temperatures. On the other hand, when the thickness T1 exceeds the above upper limit, a problem such as cracking and rupture occurs when the polyimide film is bent.

In addition, the total thickness T2 of the thermoplastic polyimide layers 120A and 120B with respect to the total thickness T1 of the polyimide films 100 and 101 (here, T2 means T2A in FIG. 1 and T2A+T2B in FIG. 2). ) The ratio T2/T1 is preferably 0.17 or less, and more preferably in the range of 0.10 to 0.15. When the value of this ratio is greater than 0.17, the oxygen permeability increases and the decrease in the dielectric loss tangent becomes difficult. Therefore, when used for a circuit board, for example, long-term heat-resistant adhesiveness becomes insufficient, and adaptation to high-speed transmission becomes difficult.

The lower limit of the ratio T2/T1 is not particularly limited. This is because the smaller the ratio T2/T1 is, the easier it is to reduce the oxygen permeability and the dielectric loss tangent. However, the lower the ratio T2/T1 is, the smaller the thickness ratio occupied by the thermoplastic polyimide layers 120A and 120B is, so the lower limit of the ratio T2/T1 is that of the polyimide films 100 and 101 As a value capable of securing the adhesion reliability of the wiring layer, for example, about 0.02 is preferable.

In addition, the thickness T3 of the non-thermoplastic polyimide layer 110 can be set within a predetermined range depending on the purpose of use, and is preferably within a range of 25 to 49 μm, for example, 30 to 49 μm. It is more preferable to fall within the range of. If the thickness T3 is less than the lower limit, the effect of improving the dielectric properties of the polyimide films 100 and 101 decreases, and the oxygen permeability increases, and the adhesion between the wiring layer and the insulating resin layer when repeatedly exposed to high temperatures is increased. There is a risk of deteriorating.

In general, polyimide can be produced by reacting an acid dianhydride and a diamine compound in a solvent to produce a polyamic acid, followed by heat ring closure (imidization). For example, an acid dianhydride and a diamine compound are dissolved in an organic solvent in substantially equimolar amounts, and stirred at a temperature within the range of 0 to 100° C. for 30 minutes to 24 hours for a polymerization reaction, thereby obtaining a polyamic acid as a precursor of a polyimide. During the reaction, the reaction component is dissolved so that the resulting precursor is in the range of 5 to 30% by weight, preferably 10 to 20% 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, and N-methyl-2-pi. Rolidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme And cresols. Two or more of these solvents may be used in combination, and further, aromatic hydrocarbons such as xylene and toluene may be used in combination. In addition, the amount of the organic solvent to be used is not particularly limited, but it is preferable to use it by adjusting the concentration of the polyamic acid solution obtained by the polymerization reaction to an amount of about 5 to 30% by weight.

The synthesized polyamic acid is usually advantageously used as a reaction solvent solution, but can be concentrated, diluted or substituted with another organic solvent as necessary. In addition, polyamic acid is advantageously used because it is generally excellent in solvent solubility. The viscosity of the polyamic acid solution is preferably in the range of 500 cps to 100,000 cps. If it is out of this range, defects such as thickness unevenness and streaks are liable to occur in the film during a coating operation with a coater or the like. The method of imidizing the polyamic acid is not particularly limited, and for example, a heat treatment such as heating in the above solvent at a temperature condition within the range of 80 to 400° C. for 1 to 24 hours is suitably employed.

Next, the non-thermoplastic polyimide and the thermoplastic polyimide will be described in more detail.

<Non-thermoplastic polyimide>

In the polyimide films 100 and 101, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 110 contains an acid dianhydride residue and a diamine residue. The non-thermoplastic polyimide preferably contains 60 mol% or more, and more preferably 70 mol% or more, of all monomer residues derived from all monomer components. By making the biphenyl skeleton-containing residue in the non-thermoplastic polyimide 60 mol% or more, the content ratio of the biphenyl skeleton-containing residue in the entire polyimide constituting the polyimide films 100 and 101 is increased, and the oxygen permeability is lowered. , Low dielectric loss tangent can be achieved.

(Acid dianhydride residue)

The non-thermoplastic polyimide preferably contains 35 mol% or more of acid dianhydride residues having a biphenyl skeleton among all acid dianhydride residues, and more preferably 50 mol% or more. More preferably, it is good to contain the biphenyltetrayl group represented by formula (c) in the amount described above.

The non-thermoplastic polyimide may contain, in addition to the acid dianhydride residue having a biphenyl skeleton described above, a residue of an acid dianhydride that is generally used as a raw material for a polyimide within a range that does not impair the effects of the invention. As such acid dianhydride residues, for example, pyromellitic dianhydride (PMDA), 1,4-phenylenebis (trimellitic acid monoester) dianhydride (TAHQ), 2,3,6,7-naphthalenetetracar Acid dianhydride (NTCDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 2,2',3,3'-, 2 ,3,3',4'- or 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,3',3,4'-diphenylethertetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, 3,3",4,4"-, 2,3,3",4"- or 2,2",3,3"-p-terphenyltetra Carboxylic acid 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-anthracenetetracarboxylic dianhydride, 2,2-bis(3 ,4-dicarboxyphenyl)tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8 -Naphthalenetetracarboxylic 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 Water, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-ratio And acid dianhydride residues derived from aromatic tetracarboxylic dianhydrides such as s(2,3-dicarboxyphenoxy)diphenylmethane dianhydride and ethylene glycol bisanehydrotrimellitate.

(Diamine residue)

The non-thermoplastic polyimide preferably contains 70 mol% or more of diamine residues having a biphenyl skeleton among all diamine residues, and more preferably 85 mol% or more. More preferably, it is good to contain the biphenyldiyl group represented by formula (b) in the amount described above. The biphenyldiyl group represented by the formula (b) has a rigid structure and has the effect of imparting an ordered structure to the entire polymer, so it can lower the dielectric loss tangent by suppressing the motion of molecules while lowering the oxygen permeability. have.

The non-thermoplastic polyimide may contain, in addition to the diamine residue having a biphenyl skeleton described above, a residue of a diamine compound that can be generally used as a raw material for a polyimide within a range that does not impair the effects of the invention. As such diamine moieties, for example 1,4-diaminobenzene (p-PDA; paraphenylenediamine), 4-aminophenyl-4'-aminobenzoate (APAB), 3,3'-diaminodiphenyl Methane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfone, 3,3'-diaminodiphenyl ether, 3,4 '-Diaminodiphenylether, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylpropane, 3,4'-diaminodiphenylsulfide, 3,3'-diaminobenzo Phenone, (3,3'-bisamino)diphenylamine, 1,4-bis(3-aminophenoxy)benzene, 3-[4-(4-aminophenoxy)phenoxy]benzeneamine, 3-[ 3-(4-aminophenoxy)phenoxy]benzeneamine, 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,3-bis(3-aminophenoxy)benzene (APB) , 4,4'-[2-methyl-(1,3-phenylene)bisoxy]bisaniline, 4,4'-[4-methyl-(1,3-phenylene)bisoxy]bisaniline, 4 ,4'-[5-methyl-(1,3-phenylene)bisoxy]bisaniline, bis[4,4'-(3-aminophenoxy)]benzanilide, 4-[3-[4-( 4-aminophenoxy)phenoxy]phenoxy]aniline, 4,4'-[oxybis(3,1-phenyleneoxy)]bisaniline, bis[4-(4-aminophenoxy)phenyl]ether ( BAPE), bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS), bis[4-(4-aminophenoxy)phenyl]ketone (BAPK), 2,2-bis-[4-(3 -Aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), bis[4-(3-aminophenoxy)phenyl]sulfone, 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-xyl Dean, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-di Aminobiphenyl, 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, 2,5-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, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene, 6-amino-2-(4-aminophenoxy)benzoxazole, 2,6-diamino-3,5-diethyltoluene, 2,4-diamino-3,5-diethyltoluene, 2,4 Diamine residues, dimer acids derived from aromatic diamine compounds such as diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane and bis(4-amino-3-ethyl-5-methylphenyl)methane And diamine residues derived from aliphatic diamine compounds such as dimer acid-type diamines obtained by substituting two terminal carboxylic acid groups of the primary aminomethyl group or an amino group.

In the non-thermoplastic polyimide, by selecting the types of the acid dianhydride residues and diamine residues, or the respective molar ratios when two or more acid dianhydride residues or diamine residues are applied, oxygen permeability, dielectric properties, coefficient of thermal expansion, Storage modulus, tensile modulus, etc. can be controlled. In addition, in the non-thermoplastic polyimide, when it has a plurality of structural units of the polyimide, it may exist as a block or may exist at random, but it is preferable to exist at random.

It is preferable that the non-thermoplastic polyimide contains an aromatic tetracarboxylic acid residue derived from an aromatic tetracarboxylic dianhydride and an aromatic diamine residue derived from an aromatic diamine. By using both the acid dianhydride residue and the diamine residue contained in the non-thermoplastic polyimide as aromatic groups, the dimensional accuracy of the polyimide films 100 and 101 in a high-temperature environment can be improved.

It is preferable that the imide group concentration of the non-thermoplastic polyimide is 33% by weight or less. Here, "imide group concentration" means a value obtained by dividing the molecular weight of the imide group portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the concentration of the imide group exceeds 33% by weight, the hygroscopicity increases due to the increase of the polar group. By selecting the combination of the acid dianhydride and the diamine compound, by controlling the orientation of the molecules in the non-thermoplastic polyimide, the increase in CTE accompanying the decrease in the concentration of the imide group can be suppressed, thereby ensuring low hygroscopicity.

The weight average molecular weight of the non-thermoplastic polyimide is preferably in the range of 10,000 to 400,000, and more preferably in the range of 50,000 to 350,000. When the weight average molecular weight is less than 10,000, the strength of the film is lowered, and brittleness tends to occur. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity increases excessively, and there is a tendency that defects such as film thickness unevenness and streaks are likely to occur during the coating operation.

<Thermoplastic polyimide>

In the polyimide films 100 and 101, the thermoplastic polyimide constituting the thermoplastic polyimide layers 120A and 120B contains an acid dianhydride residue and a diamine residue. The thermoplastic polyimide preferably contains 30 mol% or more, and more preferably 40 mol% or more, of all monomer residues derived from all monomer components, as in the above-described condition (iv). Do. When the amount of the biphenyl skeleton-containing residue in the thermoplastic polyimide is 30 mol% or more, the content ratio of the biphenyl skeleton-containing residue in the entire polyimide constituting the polyimide films 100 and 101 is increased, thereby reducing the oxygen permeability. In addition, it is possible to achieve low-genetic tangentization. On the other hand, since thermoplastic polyimide needs to provide thermoplasticity by improving the flexibility of the polyimide molecular chain in order to secure adhesion to the metal layer, the upper limit of the content of the biphenyl skeleton-containing residue is 65 mol% or less. It is desirable to do it.

(Acid dianhydride residue)

It is preferable that the thermoplastic polyimide contains 60 mol% or more of acid dianhydride residues having a biphenyl skeleton among all acid dianhydride residues. More preferably, it is good to contain the biphenyltetrayl group represented by formula (c) in the amount described above.

In addition to the residues of the acid dianhydride having a biphenyl skeleton, the thermoplastic polyimide may contain residues of acid dianhydrides that can generally be used as a raw material for polyimide within a range that does not impair the effects of the invention. As such an acid dianhydride residue, the residue of an acid dianhydride exemplified for a non-thermoplastic polyimide can be mentioned.

(Diamine residue)

The thermoplastic polyimide preferably contains 1 mol% or more of diamine residues having a biphenyl skeleton among all diamine residues, and more preferably 5 mol% or more. More preferably, it is good to contain the biphenyldiyl group represented by formula (b) in the amount described above. Since the biphenyldiyl group represented by formula (b) has a rigid structure and has an action of imparting an ordered structure to the entire polymer, dielectric loss tangent and hygroscopicity can be reduced by suppressing the motion of molecules. Further, by using it as a raw material for a thermoplastic polyimide, a polyimide having low oxygen permeability and excellent long-term heat resistance can be obtained.

The thermoplastic polyimide may contain, in addition to the diamine residue having a biphenyl skeleton described above, a residue of a diamine compound that can be generally used as a raw material for a polyimide within a range that does not impair the effects of the invention. As such a diamine residue, the residue of the diamine compound exemplified for the non-thermoplastic polyimide can be mentioned.

In the thermoplastic polyimide, by selecting the types of the acid dianhydride residues and diamine residues, or the respective molar ratios when two or more acid dianhydride residues or diamine residues are applied, the coefficient of thermal expansion, the tensile modulus, the glass transition temperature, etc. Can be controlled. In addition, in the case of having a plurality of structural units of the polyimide in the thermoplastic polyimide, it may be present as a block or may be present at random, but it is preferably present at random.

It is preferable that the thermoplastic polyimide contains an aromatic tetracarboxylic acid residue derived from an aromatic tetracarboxylic dianhydride and an aromatic diamine residue derived from an aromatic diamine. When both the acid dianhydride residues and the diamine residues contained in the thermoplastic polyimide are aromatic groups, deterioration of the polyimide in the high temperature environment of the polyimide films 100 and 101 can be suppressed.

It is preferable that the concentration of the imide group of the thermoplastic polyimide is 30% by weight or less. Here, "imide group concentration" means a value obtained by dividing the molecular weight of the imide group portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the concentration of the imide group exceeds 30% by weight, the elastic modulus at a temperature equal to or higher than the glass transition temperature is difficult to decrease, and the low hygroscopicity is also deteriorated due to an increase in the polar group.

The weight average molecular weight of the thermoplastic polyimide is preferably in the range of 10,000 to 400,000, and more preferably in the range of 50,000 to 350,000. When the weight average molecular weight is less than 10,000, the strength of the film is lowered, and brittleness tends to occur. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity increases excessively, and there is a tendency that defects such as film thickness unevenness and streaks are likely to occur during the coating operation.

In the polyimide films 100 and 101, the thermoplastic polyimide layers 120A and 120B function as an adhesive layer, and the adhesion with a metal layer such as copper foil can be improved. Therefore, the glass transition temperature of the thermoplastic polyimide is preferably in the range of 200°C or more and 350°C or less, and more preferably in the range of 200°C or more and 320°C or less.

Since the thermoplastic polyimide becomes, for example, an adhesive layer in contact with the wiring layer of a circuit board, a completely imidized structure is most preferable in order to suppress diffusion of copper. However, a part of the polyimide may be made of amic acid. The imidization ratio is, the Fourier transform infrared spectrophotometer (commercially available product: manufactured by Nippon Bunko FT / IR620) using, by measuring the infrared absorption spectrum of the polyimide thin film in one reflection ATR method time, the benzene ring in the vicinity 1015㎝ ^-1 Based on the absorber, it is calculated from the absorbance of the C=O stretch derived from an imide group of ^{1780 cm -1.}

<Form of polyimide film>

The polyimide films 100 and 101 of the present embodiment are not particularly limited as long as they satisfy the above conditions, and may be a film (sheet) containing an insulating resin, for example, a metal foil such as copper foil, a glass plate, or a polyimide film. It may be a film of an insulating resin laminated on a substrate such as a resin sheet such as a mid-based film, a polyamide-based film, or a polyester-based film.

<genetic tangent>

When the polyimide films 100 and 101 are applied as an insulating resin layer of a circuit board, for example, in order to reduce dielectric loss during transmission of high-frequency signals, the entire film is divided into a split post dielectric resonator (SPDR). It is preferable that the dielectric loss tangent (Tan δ) at 10 GHz measured by) is 0.004 or less. In order to improve the transmission loss of the circuit board, it is particularly important to control the dielectric loss tangent of the insulating resin layer, and by making the dielectric loss tangent within the above range, the effect of lowering the transmission loss is increased. Therefore, when the polyimide films 100 and 101 are applied as an insulating resin layer of a high frequency circuit board, for example, transmission loss can be efficiently reduced. If the dielectric loss tangent at 10 GHz exceeds 0.004, when the polyimide films (100, 101) are applied as the insulating resin layer of the circuit board, problems such as increased loss of electrical signals on the transmission path of high-frequency signals occur. It becomes easy to do. Although the lower limit of the dielectric loss tangent in 10 GHz is not particularly limited, it is necessary to consider the control of physical properties when the polyimide films 100 and 101 are applied as an insulating resin layer of a circuit board.

<Dielectric constant>

In the case of applying the polyimide films 100 and 101 as an insulating resin layer of a circuit board, for example, in order to ensure impedance matching, it is preferable that the dielectric constant at 10 GHz is 4.0 or less as a whole. If the dielectric constant at 10 GHz exceeds 4.0, when the polyimide films 100 and 101 are applied as the insulating resin layer of the circuit board, the dielectric loss will deteriorate, resulting in loss of electrical signals on the transmission path of the high frequency signal. It becomes easy to cause problems such as increase in size.

<filler>

The polyimide films 100 and 101 of the present embodiment may contain an inorganic filler or an organic filler in the non-thermoplastic polyimide layer 110 or the thermoplastic polyimide layers 120A and 120B, if necessary. Specifically, examples include inorganic fillers such as silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and organic fillers such as fluorine-based polymer particles or liquid crystal polymer particles. I can. These can be used alone or in combination of two or more. In addition, when it contains an organic filler, it is assumed that the organic filler does not correspond to all the monomer components constituting the non-thermoplastic polyimide layer 110 or the thermoplastic polyimide layers 120A and 120B.

[Production method of polyimide film]

As a preferable aspect of the manufacturing method of the polyimide films 100 and 101 of this embodiment, the following [1]-[3] can be illustrated, for example.

[1] A method of producing a polyimide film (100, 101) by repeating coating and drying a polyamic acid solution on a supporting substrate a plurality of times, and then imidizing.

[2] After applying and drying the polyamic acid solution to the supporting substrate a plurality of times, the gel film of polyamic acid is peeled off from the supporting substrate and imidized to produce polyimide films (100, 101). Way.

[3] A method of producing the polyimide films 100 and 101 by performing imidization after coating and drying in a state in which a polyamic acid solution is simultaneously laminated in multiple layers by multilayer extrusion (hereinafter, a multilayer extrusion method).

The method of the above [1] includes, for example, the following steps 1a to 1c;

(1a) a step of applying a polyamic acid solution to a supporting substrate and drying it,

(1b) a step of forming a polyimide layer by imidizing polyamic acid by heat treatment on a supporting substrate, and

(1c) Step of obtaining polyimide films (100, 101) by separating the supporting substrate and the polyimide layer

It may include.

The method of the above [2] includes, for example, the following steps 2a to 2c;

(2a) a step of applying a polyamic acid solution to the supporting substrate and drying it,

(2b) the step of separating the supporting substrate and the gel film of polyamic acid, and

(2c) Step of obtaining polyimide films (100, 101) by imidizing a gel film of polyamic acid by heat treatment

It may include.

In the method of [1] or [2], a laminated structure of a polyamic acid can be formed on the supporting substrate by repeating the step 1a or the step 2a a plurality of times. In addition, the method of applying the polyamic acid solution on the supporting substrate is not particularly limited, and for example, it can be applied with a coater such as a comma, die, knife, or lip.

The method of [3] is, in step 1a of the method of [1] or step 2a of the method of [2], except for simultaneously applying and drying the laminated structure of polyamic acid by multilayer extrusion. , It can be carried out similarly to the method of [1] or the method of [2].

It is preferable that the polyimide films 100 and 101 produced in the present embodiment complete the imidization of the polyamic acid on the supporting substrate. Since the resin layer of polyamic acid is imidized while being fixed to the supporting substrate, changes in the stretch and contraction of the polyimide layer during the imidization process can be suppressed, and the thickness and dimensional accuracy of the polyimide films 100 and 101 can be maintained. have.

[Metal Clad Laminate]

The metal-clad laminate of the present embodiment includes an insulating resin layer and a metal layer provided on at least one side of the insulating resin layer, and a part or all of the insulating resin layer is a polyimide film 100 of the above embodiment. 101) should just be used. In order to improve the adhesiveness between the insulating resin layer and the metal layer, the layer in contact with the metal layer in the insulating resin layer is preferably the thermoplastic polyimide layers 120A and 120B.

The material of the metal layer is not particularly limited, but, for example, copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, and alloys thereof And the like. Among these, copper or a copper alloy is particularly preferable. In addition, the material of the wiring layer in the circuit board described later is also the same as that of the metal layer.

The thickness of the metal layer is not particularly limited, but when a metal foil typified by copper foil is used, for example, it is preferably 35 µm or less, more preferably 5 to 25 µm. From the viewpoint of production stability and handling properties, the lower limit of the thickness of the metal foil is preferably 5 µm. Moreover, when using a copper foil, a rolled copper foil may be sufficient and an electrolytic copper foil may be sufficient. Moreover, as a copper foil, a commercially available copper foil can be used.

Further, the metal foil may be subjected to surface treatment with, for example, siding, aluminum alcoholate, aluminum chelate, silane coupling agent, or the like for the purpose of, for example, rust prevention treatment or improvement of adhesive strength.

Next, with respect to the metal-clad laminate, a copper clad laminate in which a metal layer is formed of a copper foil is taken as an example and described in more detail. In the copper clad laminate, the copper foil is provided on one side or both sides of the insulating resin layer. That is, the copper clad laminated plate may be a single-sided copper clad laminated plate (one-sided CCL) or a double-sided copper clad laminated plate (double-sided CCL).

The copper clad laminate is prepared, for example, by preparing a resin film comprising the polyimide films 100 and 101 of the above embodiment, sputtering a metal thereto to form a seed layer, for example, by copper plating. You may prepare by forming a copper foil layer.

In addition, the copper clad laminate may be prepared by preparing a resin film comprising the polyimide films 100 and 101 of the above embodiment, and laminating a copper foil thereon by a method such as thermocompression bonding.

In addition, the copper clad laminate may be prepared by casting a coating liquid containing polyamic acid, which is a precursor of polyimide, on a copper foil, drying it to form a coating film, then heat-treating to imide it, and forming a polyimide layer. .

[Circuit board]

The metal-clad laminate of the above embodiment is mainly useful as a circuit board material such as FPC. A circuit board according to an embodiment of the present invention can be manufactured by forming a wiring layer by processing the metal layer of the metal-clad laminate into a pattern by a conventional method.

That is, the circuit board of the present embodiment includes an insulating resin layer and a wiring layer provided on at least one side of the insulating resin layer, and a part or all of the insulating resin layer is the polyimide film 100 of the above embodiment. , 101). In addition, in order to improve the adhesion between the insulating resin layer and the wiring layer, the layer in contact with the wiring layer in the insulating resin layer is preferably thermoplastic polyimide layers 120A and 120B.

Example

Examples are shown below, and features of the present invention will be described in more detail. However, the scope of the present invention is not limited to the examples. In addition, in the following examples, various measurements and evaluations are as follows, unless otherwise specified.

[Measurement of viscosity]

The viscosity at 25°C was measured using an E-type viscometer (manufactured by Brookfield, brand name; DV-II+Pro). The rotational speed was set so that the torque became 10% to 90%, and after 2 minutes elapsed after starting the measurement, the value when the viscosity stabilized was read.

[Measurement of glass transition temperature (Tg)]

The glass transition temperature is a polyimide film having a size of 5 mm x 20 mm, using a dynamic viscoelasticity measuring device (DMA: manufactured by UBM, brand name: E4000F), a heating rate of 4° C./min from 30° C. to 400° C., The measurement was performed at a frequency of 11 Hz, and the temperature at which the elastic modulus change (tan δ) became the maximum was taken as the glass transition temperature. In addition, the storage modulus at 30°C measured using DMA is 1.0×10 ⁹ Pa or more, and the storage elastic modulus in the temperature range within the glass transition temperature +30°C is less ^{than 1.0×10 8} Pa, as “thermoplastic”. The storage modulus at 30°C was 1.0×10 ⁹ Pa or more, and the storage elastic modulus in the temperature range within the glass transition temperature +30° C. was 1.0×10 ⁸ Pa or more, as “non-thermoplastic”.

[Measurement of Coefficient of Thermal Expansion (CTE)]

A polyimide film having a size of 3 mm×20 mm was heated from 30° C. to 265° C. at a constant heating rate while applying a load of 5.0 g using a thermo-mechanical analyzer (manufactured by Bruker, brand name: 4000SA), and the After holding at the temperature for another 10 minutes, it was cooled at a rate of 5°C/min, and the average coefficient of thermal expansion (coefficient of thermal expansion) from 250°C to 100°C was calculated.

[Measurement of moisture absorption rate]

Two test pieces (width; 4 cm x length; 25 cm) of the polyimide film were prepared and dried at 80°C for 1 hour. Immediately after drying, it was put into a constant temperature and humidity chamber of 23°C/50% RH, left to stand for 24 hours or more, and calculated from the weight change before and after it by the following equation.

Moisture absorption rate (% by weight) = [(weight after moisture absorption-weight after drying)/weight after drying]×100

[Measurement of dielectric constant and dielectric loss tangent]

Using a vector network analyzer (manufactured by Agilent, brand name: E8363C) and a split post dielectric resonator (SPDR resonator), the dielectric constant and dielectric loss tangent of the polyimide film at a frequency of 10 GHz were measured. In addition, the material used for the measurement is temperature; 24 to 26°C, humidity; It left to stand for 24 hours under the conditions of 45-55%.

[Calculation of imide group concentration]

The value obtained by dividing the molecular weight of the imide group portion (-(CO) ₂ -N-) by the molecular weight of the entire polyimide structure was taken as the imide group concentration.

[Measurement of surface roughness of copper foil]

The surface roughness of the copper foil is AFM (manufactured by Bruker AXS, brand name; Dimension Icon type SPM), probe (manufactured by Bruker AXS, brand name; TESPA (NCHV), tip curvature radius 10 nm, spring constant 42N/ m), in the tapping mode, it was measured in the range of 80 µm x 80 µm on the surface of the copper foil to obtain a 10-point average roughness (Rzjis).

[Measurement of oxygen permeability]

Under the conditions of a temperature of 23°C±2°C and a humidity of 65% RH±5% RH, in accordance with the differential pressure method of JIS K7126-1, the permeability of oxygen gas was measured. In addition, GTR Tech Co., Ltd. product, GTR-30XAD2, and Yanako Technical Science Co., Ltd. product, G2700T·F were used as the vapor permeability measuring device.

[Measurement of initial peel strength]

After circuit processing the copper foil of the copper clad laminated board (copper foil/multilayer polyimide layer) to a width of 1 mm in the coating direction of the resin at 10 mm intervals, the width; 8 cm x length; It was cut into 4cm. Peel strength was obtained by fixing the polyimide layer surface of the cut measurement sample to an aluminum plate with a double-sided tape using a Tensilon tester (manufactured by Toyo Seiki Seisakusho, brand name; Stograph VE-1D), and circuit-processed copper. The foil was peeled off at a rate of 50 mm/min in the 180° direction, and the median strength when peeling 10 mm from the polyimide layer was determined, and was set as the initial peel strength.

[Measurement of peel strength after heating]

After circuit processing the copper foil of the copper clad laminated board (copper foil/multilayer polyimide layer) to a width of 1 mm in the coating direction of the resin at 10 mm intervals, the width; 8 cm x length; It was cut into 4cm. The cut sample was stored in a hot air oven set at 150° C. (under atmospheric atmosphere), and taken out after 1000 hours. Peel strength was determined by using a Tensilon tester (manufactured by Toyo Seki Seisakusho, brand name; Stograph VE-1D), fixing the polyimide layer surface of the taken out measurement sample to an aluminum plate with double-sided tape, and circuit-processed copper. The foil was peeled off at a rate of 50 mm/min in the 180° direction, and the median strength was determined when peeling 10 mm from the polyimide layer.

[Measurement of the thickness of the polyimide layer]

About the copper clad laminated board, the copper foil was etched away using the ferric chloride aqueous solution, and the polyimide film was obtained. The obtained polyimide film was cut out into a rectangle and embedded with a resin, and then cut in the film thickness direction with a microtome to produce an ultra-thin section of about 100 nm. The produced ultra-thin section was observed with an acceleration voltage of 30 kV using the STEM function of Hitachi Hi-Tech Technology Co., Ltd. SEM (SU9000), and the thickness of each polyimide layer was measured at 5 points, and the average value was determined for each polyimide. It was set as the thickness of the mid layer.

The abbreviations used in Examples and Reference Examples represent the following compounds.

PMDA: pyromellitic dianhydride

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl

TPE-R: 1,3-bis(4-aminophenoxy)benzene

TPE-Q: 1,4-bis(4-aminophenoxy)benzene

DAPE: 4,4'-diamino-diphenyl ether

PDA: Paraphenylenediamine

BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane

Bisaniline-P: 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene (manufactured by Mitsui Chemical Co., Ltd., brand name; Bisaniline-P)

DDA: C36 aliphatic diamine (manufactured by Croda Japan, brand name; PRIAMINE1074, amine value; 210 mgKOH/g, mixture of dimer diamines of cyclic structure and chain structure, content of dimer component; 95% by weight or more)

DMAc: N,N-dimethylacetamide

(Synthesis Example 1)

Under a nitrogen stream, in a 300 ml separable flask, 12.061 g of m-TB (0.0568 mol), 0.923 g of TPE-Q (0.0032 mol) and 1.0874 g of bisaniline-P (0.0032 mol), and the solid content concentration after polymerization were DMAc in an amount of 15% by weight was added, and the mixture was stirred at room temperature to dissolve. Next, after adding 6.781 g of PMDA (0.0311 mol) and 9.147 g of BPDA (0.0311 mol), stirring was continued at room temperature for 3 hours to carry out a polymerization reaction to obtain a polyamic acid solution a. The solution viscosity of the polyamic acid solution a was 29,800 cps.

Next, on copper foil 1 (electrolytic copper foil, thickness; 12 μm, surface roughness Rzjis on the resin side; 2.1 μm), a polyamic acid solution a was uniformly applied so that the thickness after curing became about 25 μm, The solvent was removed by heating and drying at 120°C. Further, stepwise heat treatment from 120°C to 360°C was performed within 30 minutes to complete the imidation. About the obtained copper clad laminated board, the copper foil was etched away using ferric chloride aqueous solution, and the polyimide film a (non-thermoplastic, Tg; 316 degreeC, moisture absorption rate: 0.61 weight%) was prepared. In addition, the concentration of imide groups in the polyimide constituting the polyimide film a was 31.6% by weight.

(Synthesis Example 2)

Under a nitrogen stream, in a 300 ml separable flask, 11.825 g of m-TB (0.0557 mol), 0.905 g of TPE-Q (0.0031 mol) and 1.653 g of DDA (0.0031 mol), and the solid content concentration after polymerization was 15% by weight DMAc was added in an amount to be dissolved, followed by stirring at room temperature. Next, after adding 6.649 g of PMDA (0.0305 mol) and 8.968 g of BPDA (0.0305 mol), stirring was continued at room temperature for 3 hours to carry out a polymerization reaction to obtain a polyamic acid solution b. The solution viscosity of the polyamic acid solution b was 27,800 cps.

Next, on the copper foil 1, the polyamic acid solution b was uniformly applied so that the thickness after curing became about 25 µm, and then heated and dried at 120°C to remove the solvent. Further, stepwise heat treatment from 120°C to 360°C was performed within 30 minutes to complete the imidation. About the obtained copper clad laminated board, the copper foil was etched away using an aqueous ferric chloride solution, and the polyimide film b (non-thermoplastic, Tg; 258 degreeC, moisture absorption rate: 0.54 weight%) was prepared. In addition, the concentration of imide groups in the polyimide constituting the polyimide film b was 30.9% by weight.

(Synthesis Example 3)

Under a nitrogen stream, in a 300 ml separable flask, 11.920 g of m-TB (0.0562 mol) and 2.897 g of TPE-Q (0.0099 mol) and DMAc in an amount such that the solid content concentration after polymerization is 15% by weight were added, It was dissolved by stirring at room temperature. Next, after adding 11.354 g of PMDA (0.0521 mol) and 3.829 g of BPDA (0.0130 mol), stirring was continued at room temperature for 3 hours to carry out a polymerization reaction to obtain a polyamic acid solution c. The solution viscosity of the polyamic acid solution c was 31,200 cps.

Next, the polyamic acid solution c was uniformly applied onto the copper foil 1 so that the thickness after curing became about 25 µm, and then heated and dried at 120°C to remove the solvent. Further, stepwise heat treatment from 120°C to 360°C was performed within 30 minutes to complete the imidation. About the obtained copper clad laminated board, the copper foil was etched away using an aqueous ferric chloride solution, and the polyimide film c (non-thermoplastic, Tg; 375 degreeC, moisture absorption rate: 0.81 weight%) was prepared. In addition, the concentration of imide groups in the polyimide constituting the polyimide film c was 33.2% by weight.

(Synthesis Example 4)

In a 300 ml separable flask under a nitrogen stream, 1.548 g of PDA (0.0143 mol) and 11.465 g of DAPE (0.0573 mol), and DMAc in an amount such that the solid content concentration after polymerization is 15% by weight were added, and stirred at room temperature. Dissolved. Next, after adding 10.764 g of PMDA (0.0494 mol) and 6.223 g of BPDA (0.0212 mol), stirring was continued at room temperature for 3 hours to carry out a polymerization reaction to obtain a polyamic acid solution d. The solution viscosity of the polyamic acid solution d was 23,500 cps.

Next, the polyamic acid solution d is cast from the slit of the T-die mold to a thickness of 25 μm after curing, and extruded on a smooth belt-shaped metal support in a drying furnace to form a thin film, and for a predetermined time at 130°C. After heating, it peeled off from a support body, and the self-supporting film was obtained. In addition, the self-supporting film was gripped at both ends in the width direction and inserted into a continuous heating furnace, and the film was heated and imidized under conditions that the maximum heating temperature from 100°C to 380°C, and the polyimide film d ( Thermoplastic, Tg; >400°C, moisture absorption rate: 1.14% by weight) was prepared. In addition, the concentration of imide groups in the polyimide constituting the polyimide film d was 36.2% by weight.

(Synthesis Example 5)

In a 300 ml separable flask under a nitrogen stream, 15.591 g of BAPP (0.0380 mol) and DMAc in an amount having a solid content concentration of 12% by weight after polymerization were added, followed by stirring at room temperature to dissolve. Next, after adding 8.409 g of PMDA (0.0386 mol), stirring was continued at room temperature for 3 hours to carry out a polymerization reaction to obtain a polyamic acid solution e. The solution viscosity of the polyamic acid solution e was 2,350 cps.

Next, the polyamic acid solution e was uniformly applied onto the copper foil 1 so that the thickness after curing became about 10 μm, and then heated and dried at 120° C. to remove the solvent. Further, stepwise heat treatment from 120°C to 360°C was performed within 30 minutes to complete the imidation. About the obtained copper clad laminated board, the copper foil was etched away using an aqueous ferric chloride solution, and the polyimide film e (thermoplastic, Tg; 320 degreeC, moisture absorption rate: 0.55 weight%) was prepared. In addition, the concentration of imide groups in the polyimide constituting the polyimide film e was 23.6% by weight.

(Synthesis Example 6)

In a 300 ml separable flask under a nitrogen stream, 1.847 g of m-TB (0.0087 mol) and 10.172 g of TPE-R (0.0348 mol) and DMAc in an amount such that the solid content concentration after polymerization becomes 12% by weight were added, It was dissolved by stirring at room temperature. Next, after adding 2.889 g of PMDA (0.0132 mol) and 9.092 g of BPDA (0.0309 mol), stirring was continued at room temperature for 3 hours to carry out a polymerization reaction to obtain a polyamic acid solution f. The solution viscosity of the polyamic acid solution f was 2,210 cps.

Next, the polyamic acid solution f was uniformly applied onto the copper foil 1 so that the thickness after curing became about 10 μm, and then heated and dried at 120° C. to remove the solvent. Further, stepwise heat treatment from 120°C to 360°C was performed within 30 minutes to complete the imidation. About the obtained copper clad laminated board, copper foil was etched away using ferric chloride aqueous solution, and the polyimide film f (thermoplastic, Tg; 226 degreeC, moisture absorption rate: 0.41 weight%) was prepared. In addition, the concentration of imide groups in the polyimide constituting the polyimide film f was 27.4% by weight.

[Example 1]

After the polyamic acid solution f was uniformly coated on copper foil 2 (electrolytic copper foil, thickness; 12 μm, surface roughness Rzjis on the resin side; 0.6 μm) so that the thickness after curing became 2.5 μm, at 120° C. for 1 minute The solvent was removed by heating and drying. The polyamic acid solution a was uniformly applied thereon so that the thickness after curing became 25 μm, followed by heating and drying at 120° C. for 3 minutes to remove the solvent. Further, polyamic acid f was uniformly coated thereon so that the thickness after curing became 2.5 µm, and then heated and dried at 120° C. for 1 minute to remove the solvent. Thereafter, heat treatment was performed in stages from 140° C. to 360° C. to complete imidization, and a copper clad laminate 1 was prepared.

Using the obtained copper-clad laminate 1, the initial peel strength and the peel strength after heating were measured, and they were 1.06 kN/m and 0.69 kN/m, respectively. Table 1 shows the results of each measurement.

About the copper clad laminated board 1, the copper foil was etched away using a ferric chloride aqueous solution, and the polyimide film 1a was obtained. CTE, dielectric properties, and oxygen permeability were evaluated about the obtained polyimide film 1a, and as a result, CTE; 22 ppm/K, permittivity; 3.56, genetic loss tangent; 0.0032, oxygen permeability; It was 4.59×10 ^-14 mol/(m2·s·Pa). Table 2 shows the results of each measurement.

[Examples 2 to 4, Comparative Example 1 and Reference Examples 1 to 2]

Copper clad laminates 2 to 4 of Examples 2 to 4, Comparative Examples 1 and 1 to 2 were carried out in the same manner as in Example 1, except that the polyamic acid solution described in Table 1 was used and the thickness configuration was changed. , Copper clad laminates 5 and copper clad laminates 6 to 7 and polyimide films 2a to 4a, polyimide films 5a, and polyimide films 6a to 7a were obtained. Each measurement result is shown in Table 1 and Table 2.

Comparative Example 2

After curing the polyamic acid solution d from the slit of the T-die mold, casting it to a thickness of 30 μm, extruding it on a smooth belt-shaped metal support in a drying furnace to form a thin film, and heating at 130° C. for a predetermined time, It peeled off from a support body and obtained the self-supporting film. Further, while continuously conveying the self-supporting film, the polyamic acid solution e was cured on the air surface of the self-supporting film using a die coater so that the thickness became 2.5 μm, and dried in a drying furnace at 120° C. for a predetermined time. . Subsequently, the polyamic acid solution e was applied to the surface opposite to the coated surface as described above so that the thickness of the polyamic acid solution e became 2.5 mu m after curing, and dried in a drying furnace at 120°C for a predetermined time.

Both ends of this self-supporting film in the width direction were gripped and inserted into a continuous heating furnace, and the film was heated and imidized under the condition that the maximum heating temperature from 100°C to 380°C to obtain a polyimide film 8b. Copper foil on one side of this polyimide film 8b, and a Teflon (registered trademark) film on the other side were superimposed on the other side, thermocompressed for 15 minutes at a temperature of 320°C and a pressure of 340 MPa, and then a Teflon (registered trademark) film was formed. The copper clad laminate 8 was prepared by peeling.

Using the obtained copper-clad laminate 8, the initial peel strength and the peel strength after heating were measured, and as a result, they were 1.15 kN/m and 1.01 kN/m, respectively.

About the copper clad laminated board 8, it carried out similarly to Example 1, and the copper foil was etched away, and the polyimide film 8a was obtained. About the obtained polyimide film 8a, CTE, dielectric properties, and oxygen permeability were evaluated as a result of CTE; 22 ppm/K, permittivity; 3.65, genetic loss tangent; 0.0073, oxygen permeability; It was 1.17×10 ^-14 mol/(m2·s·Pa).

As mentioned above, although the embodiment of the present invention has been described in detail for the purpose of illustration, the present invention is not limited to the above embodiment, and various modifications are possible.

100, 101: polyimide film
110: non-thermoplastic polyimide layer
120A, 120B: thermoplastic polyimide layer

Claims (6)

A polyimide film having a non-thermoplastic polyimide layer containing a non-thermoplastic polyimide and a thermoplastic polyimide layer containing a thermoplastic polyimide laminated on at least one side of the non-thermoplastic polyimide layer,
The following conditions (i) to (iii);
(i) the coefficient of thermal expansion is in the range of 10 to 30 ppm/K;
(ii) Oxygen permeability of 5.5×10 ^-14 mol/(m 2 ·s·Pa) or less;
(iii) The ratio of the monomer residues having a biphenyl skeleton calculated by the following formula (1) to the total monomer residues derived from the non-thermoplastic polyimide and all the monomer components constituting the thermoplastic polyimide is 50 mol% More than one;
Polyimide film, characterized in that to meet the.

[In formula (1), M _i is the ratio of the monomer residues having a biphenyl skeleton among all monomer residues derived from all monomer components in the polyimide constituting the polyimide layer of the i-th layer (unit ; Mol%), L _i is the thickness (unit: µm) of the polyimide layer of the i-th layer, L is the thickness (unit: µm) of the polyimide film, and n is an integer of 2 or more.] The method of claim 1,
In addition to the above conditions (i) to (iii), the following conditions (iv);
(iv) the ratio of the monomer residues having a biphenyl skeleton among all the monomer residues derived from all the monomer components in the thermoplastic polyimide is 30 mol% or more;
Polyimide film, characterized in that to meet the. The method according to claim 1 or 2,
Polyimide film, characterized in that the total thickness is in the range of 30 to 60㎛. The method of claim 3,
A polyimide film in which the ratio T2/T1 of the total thickness T2 of the thermoplastic polyimide layer to the total thickness T1 of the polyimide film is 0.17 or less. It is a metal-clad laminate comprising an insulating resin layer and a metal layer provided on at least one side of the insulating resin layer,
A metal-clad laminate comprising the polyimide film according to claim 1, wherein the insulating resin layer has a thermoplastic polyimide layer in contact with the surface of the metal layer and a non-thermoplastic polyimide layer indirectly laminated. . It is a circuit board provided with an insulating resin layer and a wiring layer provided on at least one side of the said insulating resin layer,
A circuit board comprising the polyimide film according to claim 1, wherein the insulating resin layer has a thermoplastic polyimide layer in contact with the wiring layer and a non-thermoplastic polyimide layer indirectly laminated.

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