KR102001282B1 - Metal foil laminate - Google Patents

Abstract

The problem of preventing sinking (i.e., mounting) of the chip to the base film layer when the chip and the metal wiring are bonded to each other, and the bending resistance, the folding endurance, And the reduction of the springback being realized at the same time. Resistant resin composition comprising a polyimide-based resin crosslinked with an epoxy resin is a metal foil laminate of a metal foil and a base film laminated on at least one surface of the metal foil, and the following (a) and (b) And a metal foil laminate.
(a) the blending amount of the epoxy resin is 0.1% by mass or more and 10% by mass or less when the total amount of the polyimide resin and the epoxy resin is 100% by mass,
(b) N-methyl-2-pyrrolidone is added to the base film obtained by removing the metal foil from the metal foil laminates so that the concentration of the base film becomes 0.5% by mass, and the insolubility after heat treatment at 100 占 폚 for 2 hours (Insoluble fraction) of 40% or more.

Description

{METAL FOIL LAMINATE}

The present invention relates to a metal foil laminate in which a polyimide resin is laminated on at least one surface of a metal foil, and a flexible printed board using the metal foil laminate. And more particularly to a metal foil laminate suitable as a substrate for a chip on film (hereinafter referred to as COF) for mounting an electronic component such as an IC (integrated circuit) or an LSL (large scale integrated circuit).

In general, polyimide-based resins are widely used as insulating materials for electric and electronic devices because they are excellent in heat resistance, insulation, chemical resistance and the like. In particular, the flexible printed wiring board has many uses as a raw material, and is widely used as a wiring board material for various electronic apparatuses, a substrate material for mounting such as a device mounting substrate for a display device such as a liquid crystal display device, a plasma display or an organic EL display, Board interconnection wiring boards such as terminals, digital cameras, portable game machines, and operation switch boards.

2. Description of the Related Art In recent years, there has been a demand for flexible printed wiring boards in which electronic components such as ICs and LSIs are directly mounted (mounted) by the progress of miniaturization, lightweight, and lightening of devices in applications such as liquid crystal display devices, smart phones, It is getting higher. In addition, as a mounting method of these electronic parts, the adoption of a COF system capable of mounting in a smaller space and in a higher density than in a conventional tape carrier package (hereinafter referred to as TCP) is increasing. The COF substrate refers to a composite component in which semiconductor chips such as IC and LSI are directly mounted on a film-like wiring board. In most cases, a COF substrate is used for a display device device such as a larger rigid wiring board, a liquid crystal display device, And is used by being connected to a mounting substrate.

The COF substrate is made of a two-layered metal foil laminate (two-layer flexible metal foil laminate) in which a metal foil such as a copper foil is laminated on a heat-resistant resin film such as polyimide. For example, a fine pattern is formed on a copper foil surface of a two-layer flexible metal foil laminate by a method such as photolithography, and further plating and solder resist such as tin is applied to necessary portions. The mounting of the semiconductor chip is carried out by using the ACF / ACP (bonding method using anisotropic conductive film / paste), NCF / NCP (bonding method using nonconductive film / paste) ), Ultrasonic bonding, Au-Au bonding, Au-Sn bonding, and the like. In particular, from the viewpoint of connection reliability, Au-Au bonding and Au-Sn bonding which are bonded at a temperature of 400 ° C or higher are widely used. Thereafter, they are connected to another rigid wiring board or the like to be mounted on a panel or the like to become a final product to be connected. In most cases, the U-shape is bent and incorporated.

These COF substrates are becoming finer patterned, and various problems have arisen due to the advancement and higher density of IC packaging technology, and the miniaturization, weight reduction, and lightening of electronic equipment to be used. For example, due to the deformation of the polyimide resin layer at the chip mounting temperature, there are problems such as " chip bumps sink " and the like. Or, there is a problem that the folding endurance is lowered due to the fine patterning. Further, due to miniaturization, lightening, and lightening of electronic equipment, when incorporated into a final product, it is mounted in a more compact shape such as a U-shape or U-shape. As a result, springback of the substrate material And problems such as occurrence of a problem in a joint portion with a final product such as a panel are generated. For this reason, more sophisticated characteristics are required for the substrate material.

As a two-layer flexible metal foil laminate that is a raw material of the COF substrate, there have been conventionally used a laminate type (Patent Document 1) in which a) a metal foil and a polyimide film are bonded with a thermoplastic polyimide adhesive, b) a polyimide resin is cast C) a metalizing type (Patent Document 3) in which a metal such as Cr is directly deposited on the polyimide film by sputtering or the like, and electroless and / or electrolytic plating of copper is carried out, . Generally, in the case of the metalizing type two-layer flexible metal foil laminate, there is no problem such as sinking of the bump at the mounting temperature, but there is a problem that the bonding property and the bending property are poor, . Further, when the COF board is folded and mounted on the springback circuit, the lead terminals connected to the external circuit are likely to be disconnected. On the other hand, in the case of the cast-type and laminate-type two-layer flexible metal foil laminate, adhesiveness and endurance can manifest a certain degree of characteristics, but there are problems such as sinking of bumps at the time of semiconductor chip mounting, In the pattern, the endurance was also not a satisfactory characteristic. In addition, the problem of springback is not solved.

As described above, the characteristics of the COF substrate obtained by the process for producing the two-layer flexible metal foil laminate have a one-end characteristic. For example, there is a problem in that the bump in the semiconductor chip mounting, sinking of the bump, , And the problem of springback at the time of assembly are not presently present. The two-layer flexible metal foil laminate satisfies all the various problems.

For example, Patent Document 4 and Patent Document 5 disclose a two-layer flexible metal foil laminate in which the sinking of bumps is improved by a casting method, but the problem of bending resistance and springback is not solved. In Patent Document 6, improvement of the bending resistance is examined by the laminate method, but improvement of sinking of the bump is insufficient. In Patent Documents 7 and 8, the improvement of the springback and the improvement of the adhesiveness are studied by the metallizing method, but it is still insufficient and the problem of the endurance is also inferior.

On the other hand, conventionally, for the purpose of improving the heat resistance of polyimide resin, polyamideimide resin and the like, a crosslinking agent such as an epoxy resin is blended in these resins and used as an adhesive or the like. However, in a resin having a high glass transition point such as a polyimide resin, the molecular mobility is inferior, so that the crosslinking reaction must depend on the molecular motion of the compound, and a large amount of the crosslinking agent can not be mixed. Alternatively, a functional group which is a crosslinking point may be introduced into the side chain of the resin, or a large amount of a polyfunctional isocyanate, a polyfunctional phenol, a phenoxy resin or the like may be used in combination, and a polymer such as a polyimide resin may be physically and / And most of them were introduced chemically. Therefore, even if a certain degree of heat resistance can be imparted, it is difficult to impart a mounting property of 400 DEG C or higher, and mechanical properties such as bending resistance and bending resistance are lowered. It is difficult to satisfy both the springback.

For example, Patent Document 9 discloses a case where a large amount of an epoxy resin is blended with a polyamide-imide resin, and Patent Document 10 discloses a case where a crosslinkable composition is obtained by using a phenoxy resin in combination. In Patent Documents 11 and 12, a functional group which is a crosslinking point is introduced into the polyimide resin. In Patent Document 13, Patent Document 14, Patent Document 15 and Patent Document 16, an epoxy resin or phenoxy resin To thereby effect efficient crosslinking. However, it has been a problem that it is difficult to obtain a molded article which is robust in any resin composition, and it is difficult to achieve compatibility between the bending resistance, the bending resistance, the flexibility, and the low springback,

Japanese Patent Application Laid-Open No. 2000-273430 Japanese Patent Application Laid-Open No. 2010-150552 Japanese Patent Laid-Open Publication No. 18386/2007 Japanese Patent Application Laid-Open No. 2006-130747 Japanese Patent Application Laid-Open No. 2006-21455 Japanese Patent Application Laid-Open No. 2012-006200 Japanese Patent Laid-Open No. 2003-71983 Japanese Patent Laid-Open Publication No. 18386/2007 Japanese Patent Application Laid-Open No. 2009-147289 Japanese Patent Application Laid-Open No. 2013-35930 Japanese Patent Application Laid-Open No. 11-184508 Japanese Patent Laid-Open No. 2007-169454 Japanese Patent Application Laid-Open No. 2008-248114 Japanese Patent Application Laid-Open No. 2009-270054 Japanese Patent Application Laid-Open No. 2005-306956 Japanese Patent Application Laid-Open No. 2009-147116

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal foil laminate for a flexible printed circuit board such as a COF substrate and a flexible printed wiring board inexpensively.

That is, the present invention relates to a metal foil laminate suitable for use as a substrate for COF, and the characteristics such as the warp of the substrate, the dimensional accuracy and the adhesiveness are maintained at a high quality as before, (That is, low springbacks), which are problematic in the case of bending resistance, bending resistance, flexibility, and bending and mounting of the substrate, which are related to the prevention of sinking into the layer ) At the same time.

As a result of intensive studies, the present inventors have achieved the object of the present invention by forming a crosslinked structure with a resin composition by blending a small amount of an epoxy resin into a polyimide resin excellent in solvent availability and heat resistance. On the other hand, the epoxy resin used in the present invention functions as a crosslinking agent.

In the crosslinked structure of the present invention, an epoxy resin is added to a polyimide resin which defines various properties, and the reaction conditions described later are used to form a crosslinked structure only with the functional group at the terminal of the resin of the polyimide resin , Low warpage property, dimensional accuracy, adhesiveness and the like satisfy both the mounting property, the bending resistance, the bending resistance, the flexibility and the low springback while maintaining the conventional characteristics. Concretely, it is possible to maintain the mechanical properties such as resistance to bending, bending resistance, flexibility and low springiness inherent in the resin by making the cross-linking point only the end of the resin which defines the composition, molecular weight, acid value and logarithmic viscosity, I was able to find the structure.

That is, the present invention is a flexible metal foil laminate and a flexible printed board as described below.

(Item 1)

Resistant resin composition comprising a polyimide-based resin crosslinked with an epoxy resin is a metal foil laminate of a metal foil and a base film laminated on at least one surface of the metal foil, and the following (a) and (b) A metal foil laminate characterized by;

(a) the amount of the epoxy resin blended is 0.1% by mass or more and 10% by mass or less when the total amount of the polyimide resin and the epoxy resin is 100% by mass;

(b) N-methyl-2-pyrrolidone is added to the base film obtained by removing the metal foil from the metal foil laminates so that the concentration of the base film becomes 0.5% by mass, and the insolubility after heat treatment at 100 占 폚 for 2 hours (Insoluble fraction) of 40% or more.

(Item 2)

The metal foil laminate according to item 1, which is the following (c) and / or (d):

(c) the polyimide resin before crosslinking has a logarithmic viscosity of from 0.40 dl / g to 3.50 dl / g in the case of N-methyl-2-pyrrolidone (polymer concentration: 0.5 g / Or less;

(d) the logarithmic viscosity of the uncrosslinked polyimide resin after cross-linking with an epoxy resin was measured in N-methyl-2-pyrrolidone (polymer concentration: 0.5 g / dl) Between 0.40 dl / g and not more than 3.50 dl / g.

(Item 3)

The metal foil laminate according to any one of the items 1 to 3, which is the following (e) and / or (f):

(e) The polyimide resin before crosslinking has a number average molecular weight of 10000 or more and 200000 or less.

(f) A polyimide resin having an uncrosslinked portion crosslinked by an epoxy resin having a number average molecular weight of 10000 or more and 200000 or less.

(Item 4)

The metal foil laminate according to any one of (1) to (3), which is (g) and / or (h)

(g) the acid value of the polyimide resin before crosslinking is 5 eq / ton or more and 1000 eq / ton or less;

(h) The acid value of the polyimide resin in the uncrosslinked portion after crosslinking by the epoxy resin is 5 eq / ton or more and 1000 eq / ton or less.

(Item 5)

The metal foil laminate according to any one of items 1 to 4, which is the following (i):

(i) the total amount of the polyimide resin and epoxy resin to be blended is 30% by mass or more when the total solid content in the heat-resistant resin composition is 100% by mass.

(Item 6)

The metal foil laminate according to any one of (1) to (5), which is the following (j):

(j) the polyimide resin is a polyamideimide resin and the repeating structural unit represented by the formula (1) is contained in the structural units of the polyamideimide resin in an amount of 5 mol% or more and 99 mol% or less;

(Item 7)

The metal foil laminate according to any one of (1) to (6), which is the following (k):

(k) the epoxy resin is a phenol novolak glycidyl ether of the following general formula (2).

[n is an integer of 1 to 20]

(Item 8)

A flexible printed wiring board containing the metal foil laminate according to any one of items 1 to 7.

(Item 9)

8. The flexible printed wiring board according to item 8, wherein the value of the endurance test based on JIS C 5016 is more than 190 times.

(Item 10)

8. The flexible printed wiring board according to item 8 or 9, wherein the Gurley type stiffness is less than 800 mg.

The flexible printed wiring board obtained from the metal foil laminate of the present invention can prevent the chip from sinking into the base film layer when the chip is bonded to the metal wiring, that is, (Hereinafter referred to as COF) because it has excellent flexibility, bending resistance and flexibility (panel assembling property), and is therefore suitable as a substrate for a chip on film (hereinafter referred to as COF). In addition, since the resin composition used in the present invention is soluble in an organic solvent, there is no need for a heat treatment at a high temperature, and the resin composition can be produced at low cost. Naturally, the quality required for the COF substrate is maintained at a high level, such as low warpage, dimensional accuracy, adhesiveness, and the like. Therefore, since a high-performance flexible substrate can be manufactured at low cost, there is a great deal of industrial merit.

Hereinafter, embodiments of the present invention will be described in detail.

<Polyimide Resin>

The metal foil laminate of the present invention is a laminate of the base film and the metal foil in which a base film containing a heat resistant resin composition is laminated on at least one surface of the metal foil. In the heat-resistant resin composition, it is preferable that only the functional group of the resin terminal of the polyimide resin is crosslinked by an epoxy resin.

The polyimide resin may be any resin as long as it has a thermal expansion coefficient equivalent to that of a metal foil and is excellent in heat resistance. Preferably, the resin is a polyimide resin and / or a polyamideimide resin, And / or a polyamide-imide resin soluble in an organic solvent. The polyimide resin is obtained by a polycondensation reaction of an acid component and an amine component (or an isocyanate component corresponding thereto), and examples thereof include a diisocyanate method, an acid chloride method, a low temperature solution polymerization method, And can be produced by conventionally known methods. Industrially, a diisocyanate method which can be used as a varnish for casting, which will be described later, is preferred.

On the other hand, in the present invention, "soluble in an organic solvent" means N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, Any single solvent selected from the group consisting of imidazolidinone, tetramethylurea, sulfolane, dimethylsulfoxide,? -Butyrolactone, cyclohexanone and cyclopentanone, or a mixture of at least one of these solvents with 20 mass % Or more, more preferably 15 mass% or more, and more preferably 20 mass% or more of the resin is dissolved in any one of the mixed organic solvent containing at least 10 mass%. Preferably, it is dissolved in N-methyl-2-pyrrolidone (purity of 99.9%) by 10 mass% or more, preferably 15 mass% or more, and more preferably 20 mass% or more. On the other hand, when the resin is in a solid form, the resin powder passing through 80 mesh is used in a 200 ml beaker, and if it is in a liquid state, it is used as it is. The resin powder was added to the above-mentioned organic solvent so as to be 10, 15, and 20 mass%, stirred at 25 ° C for 24 hours, and then the solution was allowed to stand at 25 ° C for 24 hours and gelled, Cloudiness, precipitation, and the like are judged to be dissolved.

The polyimide resin usable in the present invention is not particularly limited, but a polyimide resin having a functional group only at the terminal of the resin is preferable. When a functional group exists only at the resin terminal of the polyimide resin, the functional group existing only at the terminal thereof reacts with the glycidyl group of the epoxy resin. If a functional group is present at a position other than the end of the resin, a cross-linking reaction with the epoxy resin occurs, and mechanical properties such as flexural resistance, bending resistance, flexibility and low springback inherent in the resin are lowered.

As the functional group at the resin terminal of the polyimide resin, a carboxyl group, an acid anhydride group, an isocyanate group, an amino group and the like are preferable, and a carboxyl group and an acid anhydride group are particularly preferable.

Hereinafter, the polyimide resin and polyamideimide resin usable in the present invention will be described.

<Acid component of polyimide resin>

The polyimide resin usable in the present invention is not particularly limited, but a polyimide resin soluble in an organic solvent is preferable. Examples of the acid component used in the polyimide resin usable in the present invention include pyromellitic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid 3,3 ', 4,4'-diphenyl ether tetracarboxylic acid, 3,3', 4,4'-diphenylsulfonetetracarboxylic acid, 3,3 ', 4,4'-diphenyl ether tetracarboxylic acid, naphthalene-2,3,6,7-tetra Monomers such as carboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid, and naphthalene-1,4,5,8-tetracarboxylic acid monomers such as dianhydrides, dianhydrides, They can be used as a mixture of two or more.

<Amine component of polyimide resin>

Examples of the amine component (or isocyanate component corresponding thereto) used in the polyimide resin which can be used in the present invention include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene , 2,4-diaminoxylene, p-xylene diamine, m-xylene diamine, 2,4-diaminodurenene, 1,4-naphthalene diamine, 1,5-naphthalene diamine, Diaminobiphenyl (o-tolidine), 3,3'-dimethoxybenzidine, 3,3'-dimethyl-4,4'-diaminobiphenyl , 3'-diethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'- Phenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-diethoxy-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) Benzidine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,4'-diaminodiphenyl ether 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 3,3'- Diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfide, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, , 4,4'-methylenebis (2-methylaniline), 4,4'-methylenebis (2-ethylaniline), 4,4'- Benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, Bis (4-aminophenoxy) benzene, diaminophenyl, 4,4'-bis (4-aminophenoxy) Bis (4- (4-aminophenoxy) phenyl) sulfone, 2,2-bis (4- ) Hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane and the like Can be used nomeo as alone or mixture of two or more.

<Acid component of polyamide-imide resin>

The polyamide-imide resin usable in the present invention is not particularly limited, but a polyamide-imide resin soluble in an organic solvent is preferable. Examples of the acid component used in the polyamideimide resin which can be used in the present invention include trimellitic acid anhydride, diphenyl ether-3,4,4'-tricarboxylic acid anhydride, diphenylsulfone-3,4,4'-tri Monomers of tricarboxylic acid anhydrides such as carboxylic acid anhydride, benzophenone-3,4,4'-tricarboxylic acid anhydride and naphthalene-1,2,5-tricarboxylic acid anhydride may be used singly or in combination of two or more Can be used as a mixture.

In addition to the tricarboxylic acid anhydrides, dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenyl ether dicarboxylic acid, diphenylsulfone dicarboxylic acid, benzophenone dicarboxylic acid and biphenyl dicarboxylic acid And the compounds exemplified as the acid components of the polyimide resin may be used singly or as a mixture of two or more thereof. Alternatively, the dicarboxylic acid and the compound exemplified as the acid component of the polyimide resin may be used in combination.

&Lt; Amine component of polyamideimide resin >

As the amine component (or isocyanate component corresponding thereto) used in the polyamide-imide resin which can be used in the present invention, a compound exemplified as the amine component of the polyimide resin can be used.

In addition to the above-exemplified acid components and amine components, the following acid components and amine components may be used as long as the object of the present invention is not impaired.

&Lt; Copolymerizable acid component >

Examples of the acid component include aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecanoic acid, monoanhydrides of aliphatic tricarboxylic acids such as butane-1,2,4-tricarboxylic acid, dianhydrides, Dianhydrides, dianhydrides, esterified products of aliphatic tetracarboxylic acids such as esters, butane-1,2,3,4-tetracarboxylic acid and cyclopentane-1,2,3,4-tetracarboxylic acid, Alicyclic dicarboxylic acids such as cyclohexane-4,4'-dicarboxylic acid, cyclohexanetricarboxylic acid, dicyclohexyl ether-3,3 ', 4'-tricarboxylic acid, dicyclohexyl sulfone 3,4,4'-tricarboxylic acid, dicyclohexylmethane-3,4,4'-tricarboxylic acid and the like, an esterified product of an aliphatic tetracarboxylic acid such as cyclopentane-1,2, Alicyclic tetracarboxylic acid monohydrate, dianhydride, esterified product such as 3,4-tetracarboxylic acid and the like can be used alone or as a mixture. The acid component exemplified as the acid component of the polyimide resin may be used alone or as a mixture.

&Lt; Copolymerizable amine component >

Examples of the amine component include trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, 1,4-diaminocyclohexane (trans / cis mixture), 1,3-diaminocyclohexane, Cyclohexane bis (methylamine), 2,5-bis (aminomethyl) propane, 4,4'-methylenebis (cyclohexylamine) (trans sieve, cis body, trans / cis mixture), isophoronediamine, Bis (aminomethyl) bicyclo [2.2.1] heptane, 3,8-bis (aminomethyl) tricyclo [5.2.1.0] decane, 1,3- Methylenebis (2-methylcyclohexylamine), 4,4'-methylenebis (2-ethylcyclohexylamine), 4,4'-methylenebis (2,6-dimethylcyclo Hexylamine), 4,4'-methylenebis (2,6-diethylcyclohexylamine), 2,2-bis {4- (4- aminocyclohexylether) cyclohexyl} propane, 2,2- Cyclohexyl} hexafluoropropane, and alicyclic diamines such as tetramethyl Diamine, it may be used as aliphatic diamine, or a mixture of diisocyanates alone or two or more thereof corresponding to these, such as hexamethylene diamine.

The polyimide-based resin that can be used in the present invention is a polyimide-based resin that can be used as a base material for a semiconductor chip, The aromatic polyimide resin and / or the aromatic polyamideimide resin which is soluble in the organic solvent and more preferably the structural unit of the polyamideimide resin is preferably the following formula (1) ). &Lt; / RTI &gt;

Preferably contains from 5 mol% to 99 mol%, more preferably from 30 mol% to 95 mol%, still more preferably from 50 mol% to 80 mol% of the repeating unit represented by the formula (1) Polyamideimide resin is preferable. If the amount is less than 5 mol%, there may be a problem in mounting performance. If the amount is more than 99 mol%, the solubility in an organic solvent becomes insufficient, so that the workability in a solution sometimes becomes difficult.

One preferred structural unit is an acid component selected from the group consisting of trimellitic anhydride (TMA), 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3', 4,4 ' -Biphenyltetracarboxylic dianhydride (BPDA) is used as the amine component and o-tolidine (or diisocyanate) is used as the amine component and the component ratio (molar ratio) of TMA / BTDA / BPDA is 80 to 50 / 5/20 / 15-45. As the isocyanate component (or the amine component corresponding thereto), it is preferable that the o-tolylidine diisocyanate is a polyamide-imide resin having a total isocyanate component (or an amine component corresponding thereto) of 50 mol% or more. Naturally, these polyamideimide resins may be used by mixing two or more resins separately polymerized.

&Lt; Polymerization of polyimide resin &

The polyimide resin is obtained by a polycondensation reaction of an acid component and an amine component (or an isocyanate component corresponding thereto), and examples thereof include a diisocyanate method, an acid chloride method, a low temperature solution polymerization method, And can be produced by conventionally known methods. Preferably, the diisocyanate method is used in which a polymer is obtained by a deacidification reaction, and the obtained polymerization solution can be directly used as a varnish for casting, which will be described later.

In the case of the diisocyanate method, the diisocyanate component corresponding to the above-mentioned acid component and amine component is heated and polycondensed in an organic solvent at a stoichiometric amount of 100 to 200 DEG C to obtain a polyimide resin to be used in the present invention. Examples of the polymerization solvent include N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, N-dimethylacetamide, 1,3-dimethyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylacetamide, - imidazolidinone. When these solvents are used as a polymerization solvent, they can be used directly as a solution for producing a metal laminate layer described later. Some of these solvents are substituted with a hydrocarbon organic solvent such as toluene or xylene, an ether organic solvent such as diglyme, triglyme or tetrahydrofuran, or a ketone organic solvent such as methyl ethyl ketone or methyl isobutyl ketone It is also possible.

<Logarithmic Viscosity of Polyimide Resin>

The logarithmic viscosity of the polyimide resin before crosslinking by the epoxy resin of the present invention is 0.40 dl / g (logarithm of the logarithmic viscosity) at 30 DEG C in N-methyl-2-pyrrolidone (polymer concentration: 0.5 g / Preferably not less than 3.50 dl / g, more preferably not less than 0.80 dl / g and not more than 3.50 dl / g, more preferably not less than 1.00 dl / g and not more than 3.50 dl / g, g or less. When the logarithmic viscosity is less than 0.40 dl / g, mechanical properties such as flexural resistance and bending resistance of the metal foil laminate and the flexible printed wiring board become insufficient. On the other hand, when it exceeds 3.50 dl / g, the solution viscosity becomes high, so that it may be difficult to carry out the molding process for the metal foil laminate. In addition, the mounting property (denting of the base film layer at the chip mounting temperature) tends to deteriorate.

&Lt; Measurement of logarithmic viscosity &

The logarithmic viscosity of the polyimide resin before crosslinking is measured by using a powdery polymer sample prepared by reprecipitation and purification of a solution containing a polyimide resin before crosslinking with a large amount of acetone. The powdery sample was dissolved in N-methyl-2-pyrrolidone so that the polymer concentration was 0.5 g / dl, and the solution viscosity and the solvent viscosity of the solution were measured at 30 캜 by means of a Uvoledé type viscometer. The logarithmic viscosity value is calculated from the result by the following equation.

Logarithmic viscosity (dl / g) = [ln (V1 / V2)] / V3

Wherein V1 represents the solution viscosity measured by the Ubero's type viscosity tube and V2 represents the solvent viscosity measured by the Ubero's type viscosity tube, V1 and V2 are the polymer solution and the solvent (N-methyl- 2-pyrrolidone) is passed through the capillary of the viscosity tube. V3 is the polymer concentration (g / dl).

Alternatively, the varnish obtained after polymerization may be used as a measurement sample. In this case, the measurement sample solution is adjusted so that the polymer concentration is 0.5 g / dl in terms of solid content from the varnish concentration.

The logarithmic viscosity of the uncrosslinked polyimide resin after crosslinking by the epoxy resin can be measured by using an extract of the polyimide resin from which the uncrosslinked portion has been extracted in the measurement of the insoluble ratio described later. Preferably, a powdery polymer sample prepared by reprecipitation and purification of the extract with a large amount of acetone is used.

Here, the polyimide-based resin in the uncrosslinked portion is a polyimide-based resin that is not reacted with the epoxy resin in the present case, but in some cases, even when it reacts with the epoxy resin, Is also included.

The logarithmic viscosity of the polyimide resin in the uncrosslinked part after cross-linking with the epoxy resin of the present invention is expressed by the logarithmic viscosity at 30 DEG C in N-methyl-2-pyrrolidone (polymer concentration: 0.5 g / Preferably not less than 0.80 dl / g but not more than 3.50 dl / g, more preferably not less than 1.00 dl / g but not more than 3.50 dl / g, still more preferably not more than 1.30 dl / g or more and 3.50 dl / g or less. When the logarithmic viscosity is less than 0.40 dl / g, mechanical properties such as flexural resistance and bending resistance of the metal foil laminate and the flexible printed wiring board become insufficient. On the other hand, when it exceeds 3.50 dl / g, the solution viscosity becomes high, so that it may be difficult to carry out the molding process for the metal foil laminate. In addition, the mounting property (denting of the base film layer at the chip mounting temperature) tends to deteriorate.

&Lt; Number average molecular weight of polyimide resin &

The number average molecular weight of the polyimide resin before crosslinking by the epoxy resin of the present invention preferably has a molecular weight corresponding to 10000 or more and 200000 or less, more preferably 21000 or more and 180000 or less, still more preferably 47000 or more and 160000 or less to be. If the number average molecular weight is less than 10,000, the mechanical properties such as bending resistance and bending resistance of the metal foil laminate and the flexible printed wiring board may become insufficient. On the other hand, if it exceeds 200,000, the solution viscosity becomes high, so that it may be difficult to perform the forming process when the metal foil laminate is processed. In addition, the mounting property (denting of the base film layer at the chip mounting temperature) tends to deteriorate.

&Lt; Measurement of average molecular weight &

The molecular weight is measured by a GPC method using a calibration curve prepared from a standard material under the following conditions.

Mobile phase: N-methyl-2-pyrrolidone dissolved in 0.1 mass% lithium bromide

Detector: Refractive index meter (SE-51, manufactured by Showa Denko K.K.)

Standard material: Standard polystyrene of the following molecular weight

(1) 6770000

(2) 2870000

(3) 1260000

(4) 355000

(5) 102000

(6) 43900

(7) 9500

(8) 5400

(9) 2800

In addition, the column is connected in series with shodex AD800P, shodex AD805 / S, shodex AD804 / S, shodex AD803 / S and shodex AD802 / S.

The molecular weight of the uncrosslinked polyimide resin after crosslinking by epoxy can be measured by using an extract of a polyimide resin from which an uncrosslinked portion has been extracted in the measurement of the insoluble ratio described later. Preferably, a powdery polymer sample prepared by reprecipitation and purification of the extract with a large amount of acetone is used. Here, the polyimide-based resin in the uncrosslinked portion is a polyimide-based resin that does not react with the epoxy in the majority of cases in the present invention. However, some polyimide-based resins that are not completely network- ) Portion.

The number average molecular weight of the uncrosslinked polyimide resin after crosslinked by the epoxy resin of the present invention preferably has a molecular weight corresponding to 10000 or more and 200000 or less, more preferably 21000 or more and 180000 or less, Is 47000 or more and 160,000 or less. If the number average molecular weight is less than 10,000, the mechanical properties such as bending resistance and bending resistance of the metal foil laminate and the flexible printed wiring board may become insufficient. On the other hand, if it exceeds 200,000, the solution viscosity becomes high, so that it may be difficult to perform the forming process when the metal foil laminate is processed. In addition, the mounting property (denting of the base film layer at the chip mounting temperature) tends to deteriorate.

&Lt; Acid value of polyimide resin &

The acid value of the polyimide resin before crosslinking by the epoxy resin of the present invention is preferably 5 eq / ton or more and 1000 eq / ton or less, more preferably 10 eq / ton or more and 600 eq / ton or less, More preferably 15 eq / ton or more and 300 eq / ton or less, particularly preferably 20 eq / ton or more and 160 eq / ton or less. When the acid value is less than 5 eq / ton, molding processing becomes difficult when processed into the metal foil laminates, and further, the mounting property (denting of the base film layer at the chip mounting temperature) tends to deteriorate. Exceeding 1000 eq / ton may result in insufficient mechanical properties such as bending resistance and bending resistance of the metal foil laminate and the flexible printed wiring board.

&Lt; Measurement of acid value &

The acid value was measured in accordance with JIS K2501 using a potentiometric titration apparatus (AT310, manufactured by Kyoto Denshi Co., Ltd.) in 1/50 N hydrochloric acid (ethanol / dimethylformamide solution, volume ratio = 50/50) Titrate at 25 ° C. A sample to be a specimen was prepared by accurately weighing 0.1 g of a powdery polymer used for measurement of logarithmic viscosity and adding 1 dl of a mixed solvent of N-methyl-2-pyrrolidone / dimethylformamide (50/50 volume ratio) .

The acid value of the uncrosslinked polyimide resin after crosslinking by the epoxy can be measured by using an extract of the polyimide resin from which the uncrosslinked portion is extracted in the measurement of the insoluble ratio described later. Preferably, a powdery polymer sample prepared by reprecipitation and purification of the extract with a large amount of acetone is used.

Here, the polyimide-based resin in the uncrosslinked portion is a polyimide-based resin that does not react with the epoxy in the majority of cases in the present invention. However, some polyimide-based resins that are not completely network- ) Portion.

The acid value of the polyimide resin in the uncrosslinked portion after crosslinked by the epoxy resin of the present invention is preferably 5 eq / ton or more and 1000 eq / ton or less, more preferably 10 eq / ton or more and 600 eq / ton or less More preferably not less than 15 eq / ton but not more than 300 eq / ton, particularly preferably not less than 20 eq / ton and not more than 160 eq / ton. When the acid value is less than 5 eq / ton, molding processing becomes difficult when processed into the metal foil laminates, and further, the mounting property (denting of the base film layer at the chip mounting temperature) tends to deteriorate. Exceeding 1000 eq / ton may result in insufficient mechanical properties such as bending resistance and bending resistance of the metal foil laminate and the flexible printed wiring board.

&Lt; Heat resistant resin composition &

In the present invention, an epoxy resin is added to the polymerization solution of the polyimide resin obtained by the above-mentioned process, and the reaction and / or blending is carried out to obtain a heat resistant resin composition, which can be used as a casting varnish to be described later. Therefore, the preferred solvent to be used is the same as the above-mentioned polymerization solvent.

The total amount of the polyimide resin and the epoxy resin in the heat-resistant resin composition is 30 mass% or more, preferably 50 mass% or more, more preferably 70 mass% or more, more preferably 70 mass% or more, Mass% or more. If it is less than 30% by mass, the mountability may be deteriorated.

The cross-linking structure of the present invention can be obtained by adding an epoxy resin to a polyimide-based resin that defines various properties and by employing the reaction conditions to be described later, Thereby satisfying the mounting property, bending resistance, bending resistance, flexibility, and low springback at the same time.

Examples of the epoxy resin to be used in the present invention include bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, Cresol novolak type epoxy resin, polyfunctional glycidyl amine type epoxy resin, dicyclopentadiene skeleton containing epoxy resin, triglycidyl isocyanurate, biquilene type epoxy resin, fluorene type epoxy resin, epoxy containing naphthalene skeleton Resin, a triphenylmethane type epoxy resin, a tetraphenylmethane type epoxy resin, a biphenyl type epoxy resin, or a rubber modified or urethane modified epoxy resin, a heterocyclic ring containing epoxy resin, a polyfunctional alicyclic epoxy resin And glycidyl groups. Further, glycidyl ester type such as glycidyl ether such as bisphenol S diglycidyl ether, glycidyl ether such as hexahydrophthalic acid glycidyl ester and dimeric acid glycidyl ester, triglycidyl isocyanurate, tetraglycidyl Epoxycyclohexylmethyl carboxylate, epoxylated polybutadiene, epoxidized soybean oil, and the like, can be used alone or as a mixture thereof .

Basically, a compound having a functional group capable of reacting with a carboxyl group, an amino group or an isocyanate group which is a terminal functional group of a polyimide resin can be used as a crosslinking agent. Therefore, if necessary, a novolak type oxetane resin, Cetane group-containing compounds may also be used.

The oxetane group-containing compound is not particularly limited as long as it has an oxetane ring in the molecule and is curable, and examples thereof include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis - {[ (3-oxetanyl) methyl ether, 3-ethyl-3- ((3-oxetanyl) (3-ethylhexyloxymethyl) oxetane, 3-ethyl-3 - {[3- (triethoxyl) propoxy] methyl} oxetane, Hydroxymethyl (3-oxetanyl)] methyl ether, 3,3-bis (hydroxymethyl) oxetane, and oxetanyl-silsesquioxane.

These oxetane ring-containing compounds may be used singly or in combination of two or more.

Of the above-mentioned epoxy resins, preferred epoxy resins that can simultaneously satisfy mounting, bending, bending, flexibility and low springback are bisphenol A type epoxy resins, novolak type epoxy resins, dicyclopentadiene type epoxy resins, Glycidylamine type epoxy resins, naphthalene type epoxy resins, and biphenyl type epoxy resins.

For example, EPICLON (registered trademark) 840 (bisphenol A type epoxy resin) manufactured by DIC Corporation, JER154JER152, JER157S70 (novolak type epoxy resin) manufactured by Mitsubishi Kagaku Co., Ltd., DIC TETRAD (registered trademark) -X, TETRAD (registered trademark) -C (multifunctional glycidylamine type epoxy resin) manufactured by Mitsubishi Gas Kagaku Co., Ltd., HP-7200 (dicyclopentadiene type epoxy resin) , EPICLON (registered trademark) HP-4032 (naphthalene type epoxy resin) manufactured by DIC Corporation, and YX4000 (biphenyl type epoxy resin) manufactured by Mitsubishi Kagaku Co., More preferred are bisphenol A type epoxy resins, novolak type epoxy resins and dicyclopentadiene type epoxy resins, more preferably phenol novolak glycidyl ether, cresol novolak glycidyl ether, brominated phenol novolak Novolak type epoxy resins such as glycidyl ether and brominated cresol novolak glycidyl ether and bisphenol A type epoxy resins such as bisphenol A glycidyl ether and brominated bisphenol A diglycidyl ether, Phenol novolac glycidyl ether of the general formula (2).

[n is an integer of 1 to 20]

The epoxy equivalent of the epoxy resin used in the present invention is preferably 10 g / eq or more and 1000 g / eq or less, more preferably 50 g / eq or more and 500 g / eq or less, further preferably 80 g / eq or more 200 g / eq or less. When the epoxy equivalent is less than 10 g / eq, the mechanical properties such as bending resistance and bending resistance of the metal foil laminate and the flexible printed wiring board may become insufficient. If it is more than 1000 g / eq, it is difficult to form the metal foil as a metal foil laminate, and the packaging property tends to deteriorate (dent of the base film layer at the chip mounting temperature). On the other hand, the epoxy equivalent is usually determined by titration with a perchloric acid acetic acid standard solution in accordance with JIS K 7236.

The amount of the epoxy resin is preferably 0.1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 10% by mass or less, more preferably 0.1% by mass or less, Is not less than 1 mass% and not more than 8 mass%, and most preferably not less than 2 mass% nor more than 5 mass%. When the content is less than 0.1% by mass, the solderability (denting of the base film layer at the chip mounting temperature) tends to deteriorate. When the content is more than 10% by mass, mechanical properties such as bending resistance and bending resistance of the metal foil laminate, May be insufficient.

In the present invention, a curing accelerator may be used if necessary. The curing accelerator is not particularly limited so long as it can accelerate the curing reaction between the terminal functional group of the polyimide resin, carboxyl group, amino group, compound containing an isocyanate group and an oxirane ring (epoxy resin).

Examples of such curing accelerators include guanamine derivatives such as imidazole derivatives, acetoguanamine and benzoguanamine, diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide , Urea, urea derivatives, polyamines such as melamine and polybasic hydrazide, organic acid salts and / or epoxy adducts thereof, amine complexes of boron trifluoride, ethyldiamino-S-triazine, 2,4-diamino Triazine derivatives such as 2,4-diamino-6-xylyl-S-triazine, triethanolamine, triethanolamine, N, N-dimethyloctylamine, N-benzyldimethylamine, pyridine , N-methylmorpholine, hexa (N-methyl) melamine, 2,4,6-tris (dimethylaminophenol), tetramethylguanidine, 1,8-diazabicyclo [5,4,0] (Sometimes referred to as "DBU"), 1,5-diazabicyclo [4,3,0] -5-nonene (sometimes referred to as "DBN" Amines, organic acid salts thereof and / or organic phosphines such as tetraphenyl borate, polyvinyl phenol, polyvinyl phenol bromide, tributyl phosphine, triphenyl phosphine and tris-2-cyanoethyl phosphine, quaternary phosphonium salts such as n-butyl (2,5-dihydroxyphenyl) phosphonium bromide, hexadecyl tributylphosphonium chloride and tetraphenylphosphonium tetraphenylborate, benzyltrimethylammonium chloride, phenyltributylammonium chloride And the like, quaternary ammonium salts such as polycarboxylic acid anhydride, diphenyl iodonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate , A photocationic polymerization catalyst such as Irgacure 261 (manufactured by Ciba Specialty Chemicals Inc.) and Optoma SP-170 (manufactured by ADEKA Corporation), styrene-maleic anhydride resin, phenyl isocyanate and dimethacrylate And the like or an equimolar reaction, tolylene diisocyanate, isophorone equimolar reaction product of an organic polyisocyanate with an isocyanate of an amine, such as dimethylamine. These may be used alone or in combination of two or more. Among these, curing accelerators having latent curing properties are preferable, and examples thereof include organic acid salts of DBU and DBN and / or tetraphenylborate, and photocationic polymerization catalysts. These may be used singly or in combination of two or more.

The amount of the curing accelerator to be used is appropriately known in the art. Usually, the amount is not less than 0.1 parts by mass and not more than 30 parts by mass with respect to 100 parts by mass of the compound containing an oxirane ring (epoxy resin), but of course, the object of the present invention can be achieved without a catalyst.

In the present invention, a curing agent can be used if necessary. As the curing agent that catalyzes the curing reaction of the epoxy resin, any conventionally known curing agent for an epoxy resin can be used. Examples thereof include amine compounds such as diaminodiphenylmethane, diaminodiphenylsulfide, diaminobenzophenone, diaminodiphenylsulfone, diethyltriamine, triethylamine, benzyldimethylamine, and the like, triphenylphosphine Basic compounds, imidazole derivatives such as 2-alkyl-4-methylimidazole and 2-phenyl-4-alkylimidazole, acid anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride and trimellitic anhydride, boron trifluoride An amine complex of boron trifluoride such as triethylamine complex, and dicyandiamide. These may be used alone or in combination of two or more.

An appropriate amount of conventionally known one is used as the blending amount. Usually, the amount is not less than 1 part by mass and not more than 20 parts by mass based on 100 parts by mass of the compound containing an oxirane ring, but the object of the present invention can be achieved without a curing agent. When an acid anhydride is used as the curing agent, the acid anhydride reacts with the epoxy to form a part of the carboxyl group, so that the acid value of the resin can be adjusted by using an acid anhydride. That is, the acid anhydride can function not only as a simple curing agent but also to adjust the acid value.

The mixing of the epoxy resin or, if necessary, the catalyst and the curing agent is usually carried out by adding a predetermined amount to the resulting resin solution after polymerization and mixing until homogeneous. When the epoxy resin is reacted, a predetermined amount of epoxy resin is added to the resin solution, followed by heating and stirring at a temperature of 50 ° C to 200 ° C for 1 hour to 10 hours. By reacting the epoxy resin, a crosslinked structure can be formed with a smaller amount of epoxy resin.

If necessary, for the purpose of improving various properties of the metal foil laminate and the flexible printed wiring board, such as transparency, mechanical properties, electrical properties, slipperiness, flame retardancy, etc., The organic compound and the inorganic compound may be mixed or reacted. For example, a lubricant (silica, talc, silicone, etc.), an adhesion promoter, a flame retardant (phosphorus or triazine, aluminum hydroxide etc.), a stabilizer (antioxidant, ultraviolet absorber, A fluorine compound, an isocyanate compound, a block isocyanate compound, an acrylic resin, a urethane resin, a polyester resin, and a poly (arylene ether) resin. An inorganic compound such as a resin or an organic compound such as an amide resin, a phenol resin or a polyimide resin or a curing agent thereof, silicon oxide, titanium oxide, calcium carbonate or iron oxide may be used in combination within a range not hindering the object of the present invention .

&Lt; Metal foil laminate &

A metal foil laminate can be obtained by laminating a metal foil with a casting varnish containing the heat-resistant resin composition prepared as described above. That is, the metal foil laminate of the present invention is a laminate of a base film and a metal foil containing the heat resistant resin composition. In the present invention, a flexible metal foil laminate is preferable.

<Metal foil>

As the metal foil to be used in the present invention, a copper foil, an aluminum foil, a steel foil and a nickel foil can be used, and the composite foil can be used for a composite metal foil and the like. It is preferably a copper foil.

The surface of the copper foil is subjected to an organic rust treatment (benzothiazole, benzotriazole, imidazole, etc.), an inorganic rust inhibitive treatment (zinc, chromate, zinc alloy, etc.), a silane coupling agent treatment (an epoxy silane coupling agent, A ring agent, a mercapto-based silane coupling agent, etc.), a plating treatment, a baking plating treatment, and the like.

The surface roughness (Rz) of the surface (so-called M plane) on which the heat resistant resin composition is laminated is 5.0 占 퐉 or less, preferably 2.0 占 퐉 or less, and most preferably 1.0 占 퐉 or less. If the thickness exceeds 5.0 m, the patternability is poor and the haze value of the resin film layer after etching away the copper foil becomes high, so that the visibility may be deteriorated. The visibility is a measure of alignment when a semiconductor chip is mounted. Usually, since the positioning pattern is identified through the base resin film with a CCD camera, if it is too low, the mounting becomes difficult. The lower limit of the surface roughness is better as far as it is not limited, but if it is about 0.1 탆, the object of the present invention can be achieved.

More preferably, it has a gloss value of 300 or more, preferably 400 or more, more preferably 600 or more, particularly preferably 800 or more, with respect to the M plane. The glossiness is measured by JIS Z 8741-1997. Normally, the light is irradiated at an incident angle of 60 DEG, and the reflected light at 60 DEG is measured. The higher the gloss, the lower the surface roughness, and the lower the roughness not reflected in the surface roughness (Rz), and thus the smoother the surface. Therefore, the higher the value, the better, but if the value is about 800, the object of the present invention can be achieved.

The glossiness, so-called glossiness, is measured by irradiating the measurement light at a constant incident angle and measuring the intensity of the reflected light therefrom at a constant angle. For example, in JIS Z 8741-1997, 20, 45, 75 °, 85 °, and the like. In this case, when a high-gloss copper foil is used, the base film layer after the copper foil is etched off on the flexible printed board is reflected by the surface state of the copper foil, If the degree is low, the opposite is considered. However, the transparency in the case where the glossiness is used as an index is strictly an incidence angle at a certain angle, a scattering light intensity at a certain angle in the reflection angle, a small amount, and the like. As an index of transparency of the base film, It is not. That is, the alignment in the COF substrate is performed by, for example, irradiating the substrate with visible light of about 400 nm to 800 nm and subjecting the identification pattern to image processing. It is not necessarily an angle of 60 degrees, The angle of incidence to the phosphorus angle, and the angle of reflection. Therefore, there may be a case in which the degree of diffusive reflection, which is close to the vertical angle, in the base film layer after the copper foil is etched away reflecting the surface state of the copper foil, . For example, when the incident angle is 5 ° and the vertical reflection angle is small, the diffuse reflection is small. However, the surface state in which the incident angle and the reflection angle are large at 60 ° is also assumed, and electrons are more practical in aligning the COF substrate.

From the viewpoints described above, more practically, in addition to the above glossiness, the reflectance in the case of vertically irradiating the substrate with visible light of about 400 nm to 800 nm is effective for selecting a copper foil to be a metal foil laminate having more excellent visibility , More preferably at least 20%, more preferably at least 25%, and even more preferably at least 30% in the visible light region of 400 nm to 800 nm in the present invention. Below 20%, the visibility is poor. The higher the reflectance is, the better, but if it is about 80%, the object of the present invention can be achieved.

The thickness of the metal foil is not particularly limited, but for example, a metal foil of 3 to 50 m can be suitably used. The metal foil is usually in the shape of a ribbon, and its length is not particularly limited. The width of the metal foil in the form of a ribbon is not particularly limited, but is generally about 25 to 300 cm, particularly about 50 to 150 cm.

As the copper foil as described above, commercially available electrolytic foil or rolled foil can be used as it is. For example, "HLS" manufactured by Nippon Densa Co., Ltd., "FO-WS", "U-WZ" manufactured by Furukawa Denkai Co., Ltd., or "NA-VLP" manufactured by Mitsui Ginzoku Kogyo Co., , "DFF", "CF-T9D-SVR" and "CF-TGD-SV" of Fukuda Ginzoku Hakuho High School.

The method for producing the metal foil laminate of the present invention is not particularly limited, and for example, the casting varnish obtained as described above may be coated on one side of the metal foil, dried at the initial stage, and heat-treated.

The coating method is not particularly limited, and a well-known method can be applied. The viscosity of the coating liquid can be adjusted by a roll coater, a knife coater, a doctor blade coater, a gravure coater, a die coater, a multilayer die coater, a reverse coater, a reverse roll coater or the like.

In the present invention, there is no particular limitation on the initial drying conditions after application, but generally, the substrate is initially dried at a temperature 70 ° C to 130 ° C lower than the boiling point (Tb (° C)) of the solvent used in the casting varnish. If the initial drying temperature is higher than (Tb-70) ° C, foaming occurs on the coated surface. If the drying temperature is lower than (Tb-130) ° C, the drying time becomes longer and the productivity decreases. The initial drying temperature varies depending on the kind of solvent, but is generally about 60 to 150 占 폚, preferably about 80 to 120 占 폚. In general, the time required for the initial drying may be an effective time at which the solvent remaining ratio in the coating film becomes about 5 to 40% under the above-mentioned temperature condition, but it is generally about 1 to 30 minutes, particularly 2 to 15 minutes Respectively. It is preferable to further dry (secondary dry) at a temperature near the boiling point of the solvent or at a boiling point or higher.

The heat treatment conditions are not particularly limited, and drying may be performed at a temperature near the boiling point of the solvent or at a boiling point or higher, but it is generally 120 ° C to 500 ° C, preferably 200 ° C to 400 ° C. Below 120 DEG C, the drying time is prolonged and the productivity is lowered. If the temperature exceeds 500 ° C, the degradation reaction proceeds depending on the resin composition, and the base film layer may become fragile. Further, the cross-linking point with the epoxy resin is thermally decomposed and oxidized to deteriorate, thereby deteriorating the mounting property. Generally, the time required for the heat treatment may be an effective time which is such that the solvent remaining ratio in the coating film disappears under the above-mentioned temperature condition, but is generally several minutes to several tens of hours.

In the present invention, the initial drying and heat treatment may be performed under an inert gas atmosphere or under reduced pressure. In order to suppress deterioration of the resin, thermal decomposition of the crosslinking point, and deterioration, it is preferable to conduct the combined use under reduced pressure and in an inert gas atmosphere. As the inert gas, nitrogen, carbon dioxide, helium, argon and the like can be mentioned, but it is preferable to use nitrogen which is easily available. In addition, in the case of performing under reduced pressure, it is preferable to perform under a pressure of about 10 ^-5 to 10 ³ Pa, preferably about 10 ^{-1 to} 200 Pa.

In the present invention, the drying method for both the initial drying and the secondary drying is not particularly limited, but can be performed by conventionally known methods such as a roll support method and a floating method. The heat treatment may be performed by a continuous heat treatment in a heating furnace such as a tenter type, a winding in a roll state, and a heat treatment in a batch type oven. In the case of the batch type, it is preferable to wind the coated surface so as not to contact the uncoated surface.

The thickness of the heat resistant resin composition layer of the metal foil laminate (hereinafter also referred to as the base film or the base film layer) can be selected from a wide range, but is generally from about 3 to about 300 mu m, preferably from about 10 To about 100 mu m. If the thickness is less than 3 占 퐉, the mechanical properties such as film strength and handleability are poor, and in the process of mounting the COF substrate, the transportability to the carrier tape and the chip mounting performance are deteriorated. On the other hand, when the thickness exceeds 300 탆, properties such as flexibility and workability (dryness, coatability) tends to decrease. In the COF substrate, the abrasion resistance, particularly the bending resistance at the fine pitch, and the bending resistance are deteriorated, and problems such as springback also occur. If necessary, surface treatment may be carried out. For example, surface treatment such as hydrolysis, corona discharge, low-temperature plasma, physical roughening, and easy adhesion coating treatment can be performed.

&Lt; Substrate film insolubility of the metal foil laminate >

In the present invention, the substrate film insolubility of the metal foil laminate after initial drying and heat treatment is preferably not less than 40%, more preferably not less than 75%, still more preferably not less than 80%, and most preferably not less than 86% . Conversely, the initial drying and heat treatment conditions are specified as described above so that the insolubility rate falls within a predetermined range. That is, as described above, it is possible to appropriately determine the logarithmic viscosity, the number-average molecular weight, and the amount of the epoxy resin of the polyimide resin, and set the composition or acid value of the polyimide resin within a predetermined range . When the insufficiency rate is less than 40%, the mounting property is insufficient. The upper limit of the insolubility rate is not particularly limited, but if it is about 90%, the object of the present invention can be sufficiently achieved.

On the other hand, an N-methyl-2-pyrrolidone solution (sometimes referred to as &quot; an extract of a polyimide-based resin from which an uncrosslinked portion is extracted &quot;) containing a dissolving portion of the obtained base film layer, Quot ;, &quot; measurement of average molecular weight &quot;, and &quot; measurement of acid value &quot;.

<Measurement of insolubility rate>

On the other hand, the insoluble content refers to the insoluble content of the resin layer after dissolving only the base film layer of the portion from which the metal foil is removed from the metal foil laminates at a temperature of 100 ° C for 2 hours in a solution of 0.5% by mass concentration in N-methyl- And is represented by the following formula.

Insufficiency rate (%) = [Mi / Mf] x 100

(Wherein Mi represents the weight (g) of the base film layer after the dissolution treatment and Mf represents the weight (g) of the base film layer before the dissolution treatment.

The double-sided metal foil laminate having the metal foil on both sides of the present invention is obtained by bonding the resin faces of the metal foil laminate in which the metal foil is laminated on only one side formed as described above by a conventionally known method such as heat lamination, By a known method, or the like. The lamination method is not particularly limited, and conventionally known methods such as roll laminate, press laminate, and belt press laminate can be employed, and the lamination temperature is usually Tg or more of the resin, and 200 to 500 占 폚 More preferably 250 ° C to 450 ° C, and still more preferably 330 ° C to 400 ° C. If it is less than 200 ° C, the adhesion is insufficient, and if it exceeds 500 ° C, deterioration of the resin layer occurs, resulting in deterioration of mechanical properties, thermal decomposition of the crosslinking point, and deterioration of the mounting property. The laminating time is not particularly limited, but is usually 10 seconds to 10 hours, preferably 1 minute to 1 hour, and more preferably 3 minutes to 30 minutes. If it is less than 10 seconds, the adhesiveness is insufficient, and if it exceeds 10 hours, the resin layer is deteriorated and the mechanical properties tend to be lowered. In addition, the cross-linking point is thermally decomposed and thermally degraded to deteriorate the mountability.

The adhesive composition in the case of lamination through an adhesive layer is not particularly limited and may be suitably selected from the group consisting of an acrylonitrile butadiene rubber (NBR) adhesive, a polyamide adhesive, a polyester adhesive, a polyester urethane adhesive, an epoxy resin, Polyamideimide resin, polyimide resin, polyimide resin, polyimide resin, polyimide resin, polyimide resin, polyimide resin, polyimide resin, polyimide resin, polyimide resin, polyimide resin, polyimide resin and polyimide resin are preferably used from the viewpoints of mounting property, bending resistance, An ester-imide resin system, or a resin composition obtained by blending an epoxy resin into these resins.

The thickness of the adhesive layer is preferably about 1 to 30 mu m. The thickness of the adhesive is not particularly limited as long as it does not interfere with the performance of the flexible printed wiring board. However, when the thickness is too thin, sufficient adhesiveness can not be obtained. On the other hand, when the thickness is excessively thick The bending resistance, the bending resistance, the flexibility, the low spring back property, and the like may be lowered.

<Flexible Printed Circuit Board>

Using the metal foil laminate of the present invention described above, a flexible printed wiring board can be manufactured by a conventionally known process, for example, by a subtractive method or the like.

In the flexible printed wiring board obtained in the present invention, deformation of the base film layer does not occur even at a chip mounting temperature of 400 DEG C or higher. The bendability is a value of an endurance test based on JIS C 5016 before covering the circuit surface (before covering the circuit surface with a solder resist or a heat resistant film), and is larger than 190 times, preferably 700 times or more It is more than 1000 times. In addition, the Gurley type lubrication (or bending repulsion) which is an index of low springiness is lower than 800 mg, preferably 760 mg or lower, more preferably 600 mg or lower.

In the case of covering the surface of a circuit for the purpose of protecting it from the solder resist of the conductor circuit or from the dirt or scratches, the heat-resistant film is bonded to the wiring board (base substrate on which the conductor circuit is formed) A method of applying a coating agent to a wiring board by a screen printing method, or the like can be applied.

As the heat resistant film, a film such as a polyimide resin system, a polyamideimide resin system, a polyester imide resin system or the like can be used, but from the viewpoints of mounting property, bending resistance, bending resistance, flexibility and low spring back property, A film obtained from the polyimide resin of the present invention is preferable.

Examples of the adhesive include adhesives such as acrylonitrile butadiene rubber (NBR) adhesive, polyamide adhesive, polyester adhesive, polyester urethane adhesive, epoxy resin, acrylic resin, polyimide resin, polyamideimide resin and polyester imide resin Adhesives can be used. However, polyimide resin, polyamideimide resin, or epoxy resin blended resin composition is preferable from the viewpoints of mounting property, bending resistance, bending resistance, flexibility and low spring back property.

As the liquid coating agent, conventionally known epoxy or polyimide ink can be used. From the viewpoints of mounting property, bending resistance, bending resistance, flexibility and low spring back property, polyimide resin, polyamide Or a resin composition obtained by blending these resins with an epoxy resin.

It is also possible to directly bond an adhesive sheet such as an epoxy-based or polyimide-based adhesive to the wiring board. In this case, from the viewpoints of mounting property, bending resistance, bending resistance, flexibility and low spring- , A polyamide-imide resin-based resin, or an epoxy resin-blended resin composition.

As the wiring pattern of the circuit, an arbitrary pattern can be formed. The flexible printed wiring board according to the present invention is particularly advantageous especially in a circuit in which a fine wiring pattern is performed because the flexible printed wiring board of the present invention exhibits a high level of performance.

Specifically, the thickness of the wiring of the circuit can be 30 占 퐉 or less, the thickness of the wiring can be 20 占 퐉 or less, and the thickness of the wiring can be 10 占 퐉 or less. The distance between the wirings can be set to 30 mu m or less, 20 mu m or less, or 10 mu m or less.

In the case of a COF substrate, for example, a fine pattern can be formed on a copper foil surface of a two-layer metal foil laminate by a method such as photolithography, and plating can be performed at necessary portions with plating and solder resist coating . The mounting of the semiconductor chip can be carried out by a conventionally known method such as Au-Au bonding, Au-Sn bonding, etc., by connecting the COF lead pattern and the connection terminal (bump) of the chip.

<Use of Flexible Printed Board>

The flexible printed wiring board manufactured in this manner is suitable for a COF substrate and can be used as a device mounting substrate for a display device such as a liquid crystal display, a plasma display, and an organic EL display, or a substrate mounting board for a relay board between a substrate such as a smart phone, a tablet terminal, , An operation switch unit substrate, and the like, can be widely used for an IC mounting substrate material of electronic equipment in which miniaturization, light weight, and light weight are progressed.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not particularly limited by the examples. On the other hand, evaluation samples (resin powder, substrate film, flexible printed wiring board) for evaluating the characteristics of the metal foil laminate and evaluating the characteristics of the resin, flexible metal foil laminate and flexible printed wiring board are as follows.

In addition, it was confirmed from the molecular weight, the functional equivalent, and the result of quantitative determination of the functional group from NMR that the functional group is the polymer terminal.

&Lt; Measurement of logarithmic viscosity of polyimide resin &

A powdery polymer sample prepared by reprecipitation and purification of a solution containing a polyimide resin in a large amount of acetone was used. The powdery sample was dissolved in N-methyl-2-pyrrolidone so that the polymer concentration was 0.5 g / dl, and the solution viscosity and the solvent viscosity of the solution were measured at 30 占 폚 by means of a Uvorodé type viscometer. The logarithmic viscosity value was calculated from the result by the following equation.

Logarithmic viscosity (dl / g) = [ln (V1 / V2)] / V3

Wherein V1 represents the solution viscosity measured by the Ubero's type viscosity tube and V2 represents the solvent viscosity measured by the Ubero's type viscosity tube, V1 and V2 are the polymer solution and the solvent (N-methyl- 2-pyrrolidone) is passed through the capillary of the viscosity tube. V3 is the polymer concentration (g / dl).

<Measurement of Functional Group of Polyimide Resin>

The functional groups in the polyimide resin were determined by calculating the amine value and the isocyanate value as follows.

&Lt; Measurement of acid value of polyimide resin &

0.1 g of the powdery polymer used in the measurement of the logarithmic viscosity was analyzed, and a mixed solvent of N-methyl-2-pyrrolidone / dimethylformamide (50/50 ratio by volume) A sample to be titrated was prepared. Subsequently, titration was carried out using a potentiometric titration apparatus (AT310, manufactured by Kyoto Denshi Co., Ltd.) in a ratio of 1/50 N potassium hydroxide (ethanol / dimethylformamide solution, volume ratio = 50/50). The temperature was set at 25 占 폚 and measured according to JIS K2501 (or according to Application Note No. TII-9800 ver.01, Kyoto Denshi Co., Ltd.).

&Lt; Measurement of Isocyanate Value of Polyimide Resin >

A sample sample to be titrated was prepared in the same manner as in the measurement of the acid value, and the sample was diluted with 1/50 N hydrochloric acid (according to JIS K 7301 (or according to Application Note No TII-98003, Kyoto Denshi Co., Ltd.) (Back titration) using a potentiometric titration apparatus (AT310, manufactured by Kyoto Denshi Co., Ltd.) in a volume ratio (ethanol / dimethylformamide solution, volume ratio = 50/50).

&Lt; Measurement of amine value of polyimide resin &

A titration sample to be titrated was prepared in the same manner as in the measurement of the acid value, and the sample was titrated with a potentiometric titration apparatus (manufactured by Kyoto Denshi Co., Ltd., Japan) with 1/50 N hydrochloric acid (ethanol / dimethylformamide solution, AT310). Measurement was carried out according to Application Note TII-97003, Kyoto Denshi Co., Ltd.

<Measurement of Functional Group of Polyimide Resin>

Polyimide-based resin (100 mg) was dissolved in 0.6 ml of DMSO-d6 to prepare a sample. The adjusted sample was measured by ¹ H-NMR. Further, the polyimide-based resin and DMSO-d6 were mixed so that the volume ratio became 1: 1, and the sample was adjusted and measured by ¹³ C-NMR.

&Lt; Measurement of average molecular weight of polyimide resin &

The number average molecular weight and the polydispersity were measured by the GPC method. As a sample for the measurement, a resin varnish obtained by polymerization was diluted with N-methyl-2-pyrrolidone dissolved at 0.1 mass% of lithium bromide at a concentration of 0.5 g / dl. As the mobile phase, N-methyl-2-pyrrolidone obtained by dissolving lithium bromide at 0.1 mass% was used and the detector was made of standard polystyrene having a molecular weight of the following formula using a refractive index meter (SE-51 manufactured by Showa Denko K.K.) Were measured using a calibration curve.

(1) 6770000

(2) 2870000

(3) 1260000

(4) 355000

(5) 102000

(6) 43900

(7) 9500

(8) 5400

(9) 2800

In addition, the columns were connected in series with shodex AD800P, shodex AD805 / S, shodex AD804 / S, shodex AD803 / S and shodex AD802 / S.

&Lt; Method for producing metal foil laminate >

The resin solution obtained in each of the examples and comparative examples described later was applied to an electrolytic copper foil (CF-T9D-SVR, surface roughness Rz 1.1 mu m, manufactured by Fukuda Kikuchi Co., Ltd.) having a thickness of 12 mu m to a thickness of 30 mu m And then applied with a knife coater. Subsequently, the laminate was dried at a temperature of 50 to 100 DEG C until it became transparent and tack free. After that, the upper and lower surfaces of the frame were fixed to a frame made of stainless steel and heated at 200 DEG C for 60 minutes and at 220 DEG C for 60 minutes Min, 260 ° C for 10 hours, and 320 ° C for 10 minutes.

<Endurance test; Indicators of Flexibility, Low Springness>

In the endurance test which is a measure of the flexural resistance and the low springiness (repulsive force) of the flexible printed wiring board or the metal foil laminate, an evaluation sample was prepared in accordance with JIS C 5016 and measured under conditions of a load of 500 g and a bending diameter of 0.38 mm Respectively.

<Production Method of Base Film>

The test samples (base film) for evaluation of the gelling type lubrication degree, the insolubility rate and the mounting property were obtained by using the copper foil laminate obtained in each of the examples and comparative examples described later by using a cupric chloride solution of 40% The copper foil was etched away.

<Gull-like lubrication (bending repulsion): Indicators of flexibility and low springiness>

(Base film) produced by etching away the metal layer of the metal foil laminate obtained in each of the examples and comparative examples as indexes of the lapping degree of the metal foil laminate, the flexible printed wiring board, and the low spring resistance, . (Manufactured by Toyo Seisakusho Co., Ltd.), and the measured values were obtained by attaching a film test piece to a chuck of a movable arm, rotating the film at 2 rpm to the left and right, and reading the scale when the lower end of the film specimen fell off the pendulum I got it.

Measuring device; Manufactured by Toyo Seisakusho Co., Ltd. Gully lecture tester (Gully Stiffness Tester)

Sample size; 25.4 mm (width) 占 88.9 mm (length) 占 20 占 퐉 (thickness)

Arm rotation speed; 2 rpm

<Insolubility rate; Scale of Christianity>

The base film was dissolved in N-methyl-2-pyrrolidone to obtain a 0.5 mass% N-methyl-2-pyrrolidone solution of the base film layer. The solution was prepared using a 100 ml Erlenmeyer flask.

Subsequently, this solution was heat-treated at 100 DEG C for 2 hours (the Erlenmeyer flask containing the solution was placed in an oil bath at 100 DEG C) and cooled to room temperature. Then, insoluble matter in the Erlenmeyer flask was dissolved in 100 mL of N-methyl- While washing with 2-pyrrolidone, the insoluble matter was filtered off with a glass filter (No. 3G-2).

Thereafter, the glass filter was vacuum-dried at 200 ° C for 20 hours, and the weight thereof was measured. The weight of the insoluble matter was measured by subtracting the weight of the glass filter previously measured from the value. The weight Mi of the insoluble matter thus obtained and the weight Mf of the resin film were calculated by the following equations.

Insufficiency rate (%) = [Mi / Mf] x 100

(Wherein Mi represents the weight (g) of insoluble matter and Mf represents the weight (g) of the resin film.

<Mountability> Index of sinking property of IC chip bump>

An IC chip was placed on a base film, and a flip chip bonder (M95 manufactured by HISOL Corporation) was subjected to a thermocompression test under the following conditions. The base film after the test was observed by SEM, and the deformation amount due to sinking of the chip bump was measured. When the thickness was 5 占 퐉 or more,?, 2 占 퐉 or less?, And 1 占 퐉 or less?

Bonding head tool temperature; 400 ° C

Stage temperature; 100 ℃

pressure; 20 mgf / 탆 ²

&Lt; Measurement of solution viscosity >

The solution viscosity was measured with a B-type viscometer manufactured by Toyo Keiki Co., Ltd. under the condition of No. 6 rotor, 10 rpm.

(Example 1)

To the reaction vessel, 211.3 g (1.10 mols) of anhydrous trimellitic acid, 132.1 g (0.50 mols) of o-tolylidine diisocyanate, 125.3 g (0.50 mols) of 4,4'-diphenylmethane diisocyanate, And 2500 g of N-methyl-2-pyrrolidone (purity: 99.9%) were added, the temperature was raised to 100 ° C, and the reaction was continued for 5 hours. Subsequently, the reaction was carried out at 130 占 폚 for 3 hours, N-methyl-2-pyrrolidone was added to adjust the solution viscosity to 400 dPa 占 퐏, the concentration was adjusted, and the solution was cooled to room temperature. The obtained polyamide-imide resin (polyamide-imide composition A) was dissolved in a polymerization solvent, and the resin properties of logarithmic viscosity, acid value and number-average molecular weight were as shown in Table 1.

Thereafter, 24 g of phenol novolak type epoxy resin (JER154 manufactured by Mitsubishi Kagaku Co., Ltd.) (6 mass% based on the total solid content) was blended to prepare a varnish for casting. Subsequently, a metal foil laminate was produced by using the casting varnish thus obtained, and a flexible printed wiring board for evaluation of bending resistance and each substrate film for evaluation of insolubility, gelling type (index of low springiness) , And each characteristic was evaluated. The results are shown in Table 1.

(Example 2)

The polyimide imide resin varnish was prepared by changing only 1.02 moles of the trimellitic anhydride as the acid component of Example 1 and appropriately adjusting the logarithmic viscosity and molecular weight as shown in Table 1. All of the polyamide-imide resin varnishes obtained in Example 2 were dissolved in a solvent, and resin properties of the obtained resin varnishes were as shown in Table 1.

Thereafter, 12 g of phenol novolak type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corp.) (3 mass% based on the total solid content) was blended to prepare a varnish for casting. Subsequently, a metal foil laminate was produced by using the casting varnish thus obtained, and a flexible printed wiring board for evaluation of bending resistance and each substrate film for evaluation of insolubility, gelling type (index of low springiness) , And each characteristic was evaluated. The evaluation results of the characteristics are shown in Table 1.

(Comparative Example 1)

The amount of trimellitic anhydride was changed to 1.15 moles, which is the acid component of Example 1, and the polyimide imide resin varnish was prepared so as to have a logarithmic viscosity and a molecular weight as shown in Table 1. All of the polyamide-imide resin varnishes obtained in Comparative Example 1 were dissolved in a solvent, and the resin properties of the obtained resin varnishes were as shown in Table 1.

Thereafter, 4 g of phenol novolak type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corp.) (1 mass% based on the total solid content) was blended to prepare a varnish for casting. Subsequently, a metal foil laminate was produced by using the casting varnish thus obtained, and a flexible printed wiring board for evaluation of bending resistance and each substrate film for evaluation of insolubility, gelling type (index of low springiness) , And each characteristic was evaluated. The evaluation results of the characteristics are shown in Table 1.

(Example 3)

To the reaction vessel, 161.4 g (0.84 mol) of trimellitic anhydride, 50.8 g (0.16 mol) of 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3' , 15.5 g (0.05 mol) of 4'-biphenyltetracarboxylic dianhydride, 264.3 g (1.00 mol) of o-tolylidine diisocyanate, 0.6 g of potassium fluoride and N-methyl-2-pyrrolidone (purity: 99.9% 2230 g was added, the temperature was raised to 100 占 폚, and the reaction was continued for 6 hours. Subsequently, the reaction was carried out at 130 DEG C for 4 hours, N-methyl-2-pyrrolidone was added to adjust the solution viscosity to 300 dPa.s, and the concentration was adjusted and the solution was cooled to room temperature. The obtained polyamide-imide resin (referred to as polyamideimide composition B) was dissolved in a solvent, and the resin properties of logarithmic viscosity, acid value, and number average molecular weight were as shown in Table 1.

Thereafter, 12 g of phenol novolak type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corp.) (3 mass% based on the total solid content) was blended to prepare a varnish for casting. Subsequently, a metal foil laminate was produced by using the casting varnish thus obtained, and a flexible printed wiring board for evaluation of bending resistance and each substrate film for evaluation of insolubility, gelling type (index of low springiness) , And each characteristic was evaluated. The results are shown in Table 1.

(Examples 4, 5, 6, 7, 8, 9, 10 and Comparative Examples 2, 3, 4, 5)

Only the molar amount of the total of the total acid components was changed as shown in Table 1 while maintaining the molar ratio between the respective components of the total acid components of Example 3 and adjusted appropriately so as to have the logarithmic viscosity and the molecular weight shown in Table 1, Amide imide resin varnish. The polyamide-imide resins obtained in Examples 4, 5, 6, 7, 8, 9 and 10 and Comparative Examples 2, 3, 4 and 5 were all dissolved in a solvent.

Thereafter, the type of epoxy resin was changed to the content of Table 1 in the same manner as in Example 3, and a cast varnish was produced. Subsequently, a metal foil laminate was produced by using the casting varnish thus obtained, and a flexible printed wiring board for evaluation of bending resistance and each substrate film for evaluation of insolubility, gelling type (index of low springiness) , And each characteristic was evaluated. The evaluation results of the characteristics are shown in Table 1.

(Example 11)

Under a stream of nitrogen, 150.1 g (0.51 mol%) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-diphenylsulfone tetracarboxylate (1.00 mol%) of o-tolylene diisocyanate, 0.6 g of potassium fluoride and 2890 g of N-methyl-2-pyrrolidone (purity 99.9%) were added, and 100 g Lt; 0 &gt; C, and reacted for 6 hours as it was. Subsequently, the reaction was carried out at 130 占 폚 for 2 hours, N-methyl-2-pyrrolidone was added to adjust the solution viscosity to 400 dPa 占 퐏, the concentration was adjusted, and the solution was cooled to room temperature. The obtained polyimide resin (referred to as polyimide composition A) was dissolved in a solvent, and the resin properties of logarithmic viscosity, acid value, and number average molecular weight were as shown in Table 1.

Thereafter, 5 g of a phenol novolak type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corp.) (1 mass% based on the total solid content) was blended to prepare a varnish for casting. Subsequently, a metal foil laminate was produced by using the casting varnish thus obtained, and a flexible printed wiring board for evaluation of bending resistance and each substrate film for evaluation of insolubility, gelling type (index of low springiness) , And each characteristic was evaluated. The results are shown in Table 1.

(Example 12 and Comparative Examples 6, 7 and 8)

Only the molar amount of the total of the total acid components was changed as shown in Table 1 while maintaining the molar ratio between the respective components of the total acid components of Example 11 and adjusted appropriately so as to have the logarithmic viscosity and the molecular weight shown in Table 1, A mid resin varnish was produced. The polyimide resins obtained in Example 12 and Comparative Examples 6, 7 and 8 were all dissolved in a solvent, and resin properties were as shown in Table 1.

Thereafter, the epoxy resin was made in the same manner as in Example 11, and the amount of the epoxy resin was changed to that in Table 1 to prepare a varnish for casting. Subsequently, in the same manner as in Example 11, a metal foil laminate was produced, and a flexible printed wiring board for evaluation of bending resistance and each substrate film for evaluation of the insolubility rate, the gelling type lubrication degree (index of low springiness) , And each characteristic was evaluated. The evaluation results of the characteristics are shown in Table 1.

(Comparative Example 9)

A polyamideimide resin varnish was prepared in the same manner as in Example 1 except that the total acid components were trimellitic anhydride (0.99 mol) and trimellitic acid (0.11 mol). The polyamide-imide resin was dissolved in a solvent, and the resin characteristics were as shown in Table 1.

Thereafter, 4 g of phenol novolak type epoxy resin (JER154 manufactured by Mitsubishi Chemical Corp.) (1 mass% based on the total solid content) was blended to prepare a varnish for casting. Subsequently, in the same manner as in Example 1, a metal foil laminate was produced, and a flexible printed wiring board for evaluation of bending resistance and each substrate film for evaluation of the insolubility rate, the gelling type lubrication degree (index of low springiness) , And each characteristic was evaluated. The evaluation results of the characteristics are shown in Table 1.

In Table 1, the amount of epoxy (mass%) represents the amount (mass%) of the epoxy resin when the total amount of the polyimide resin and epoxy resin is 100 mass%. The polyamideimide A, polyamideimide B, polyamideimide C and polyimide A were both soluble in N-methyl-2-pyrrolidone (purity: 99.9%) at 10% by mass or more.

The polyamideimide A, the polyamideimide B, and the polyimide A of Examples 1 to 12 and Comparative Examples 1 to 8 are apparent from the production method thereof, but the acid value, the amine value, the isocyanate value, The resin also had a carboxyl group, an amino group and an isocyanate group only at the terminals. The polyamideimide C of Comparative Example 9, as measured by the same analytical method, had a carboxyl group in addition to the terminal.

The metal-clad laminate of the present invention and the flexible printed wiring board obtained therefrom have a problem in that when the semiconductor chip and the metal wiring are bonded to each other, the chip sinks to the base film layer (mounting property) And is excellent in bending resistance, bending resistance, and flexibility (panel assemblability). This makes it possible to provide a flexible printed wiring board on which electronic parts such as IC and LSI are directly mounted in applications such as liquid crystal display devices, smart phones, tablet terminals, and the like, which are becoming smaller, lighter, Can be widely used as a substrate.

Claims (10)

Resistant resin composition comprising a polyimide-based resin crosslinked with an epoxy resin is a metal foil laminate of a metal foil and a base film laminated on at least one surface of the metal foil, and the following (a) and (b) A metal foil laminate characterized by:
(a) the amount of the epoxy resin blended is 0.1% by mass or more and 10% by mass or less when the total amount of the polyimide resin and the epoxy resin is 100% by mass;
(b) N-methyl-2-pyrrolidone is added to the base film obtained by removing the metal foil from the metal foil laminates so that the concentration of the base film becomes 0.5% by mass, and the insolubility after heat treatment at 100 占 폚 for 2 hours (Insoluble fraction) of 40% or more. The metal foil laminate according to Claim 1, further comprising at least one of the following (c) and (d):
(c) the polyimide resin before crosslinking has a logarithmic viscosity of from 0.40 dl / g to 3.50 dl / g in the case of N-methyl-2-pyrrolidone (polymer concentration: 0.5 g / Or less;
(d) the logarithmic viscosity of the uncrosslinked polyimide resin after cross-linking with an epoxy resin was measured in N-methyl-2-pyrrolidone (polymer concentration: 0.5 g / dl) Between 0.40 dl / g and not more than 3.50 dl / g. The metal foil laminate according to claim 1 or 2, further comprising at least one of the following (e) and (f):
(e) the polyimide resin before crosslinking has a number average molecular weight of 10000 or more and 200000 or less;
(f) A polyimide resin having an uncrosslinked portion crosslinked by an epoxy resin having a number average molecular weight of 10000 or more and 200000 or less. The metal foil laminate according to claim 1 or 2, further comprising at least one of the following (g) and (h):
(g) the acid value of the polyimide resin before crosslinking is 5 eq / ton or more and 1000 eq / ton or less;
(h) The acid value of the polyimide resin in the uncrosslinked portion after crosslinking by the epoxy resin is 5 eq / ton or more and 1000 eq / ton or less. The metal foil laminate according to claim 1 or 2, further comprising (i)
(i) the total amount of the polyimide resin and epoxy resin to be blended is 30% by mass or more when the total solid content in the heat-resistant resin composition is 100% by mass. The metal foil laminate according to claim 1 or 2, further comprising the following (j):
(j) The polyimide resin is a polyamideimide resin, and the repeating structural unit represented by the formula (1) is contained in the structural units of the polyamideimide resin in an amount of 5 mol% or more and 99 mol% or less.

The metal foil laminate according to claim 1 or 2, further comprising (k)
(k) the epoxy resin is a phenol novolak glycidyl ether of the following general formula (2).

[n is an integer of 1 to 20] A flexible printed wiring board containing the metal foil laminate according to any one of claims 1 to 3. The flexible printed wiring board according to claim 8, wherein the value of the folding endurance (folding endurance) test based on JIS C 5016 is more than 190 times. 9. The flexible printed wiring board according to claim 8, wherein the Gurley type stiffness is less than 800 mg.