JP5110242B2 - Polyimide, polyimide film and laminate - Google Patents

Description

  The present invention relates to a novel polyimide, polyimide film and laminate, and more specifically, tetracarboxylic dianhydride containing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride as an essential component. Is a starting tetracarboxylic dianhydride component, a diamine having an aromatic diamine having a specific structure as an essential component is a starting diamine component, a polyimide having a high moisture transmission rate and improved adhesion, The present invention relates to a polyimide film having a polyimide layer formed on at least one side and a laminate.

  The 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride-based polyimide that gives heat-resistant polyimide includes 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and paraphenylenediamine. Are generally used as starting acid dianhydride components and starting diamine components, respectively, and it is known to give a polyimide having a low coefficient of linear expansion and a high elastic modulus. Moreover, since the film which consists of this polyimide is excellent in a thermal property and an electrical property, it is widely used for the use of electronic devices.

A polyimide using a diamine having an alkyl group, a carboxyl group or a hydroxyl group in the side chain has been produced.
In Patent Document 1, a polyimide precursor comprising an aromatic tetracarboxylic acid anhydride, a target aromatic diamine having no substituent and an asymmetric aromatic primary diamine having a substituent is used as a metal thin film. The manufacturing method of the flexible wiring board which apply | coated and heated to make the polyimide layer is disclosed.
Patent Document 2 discloses a circuit board comprising a metal foil and a polyimide resin thin film formed on the surface of the metal foil, and 95 mol% of 3,3 ′, 4,4′-benzophenonetetracarboxylic acid. A polyimide obtained by reacting the aromatic tetracarboxylic acid containing the above and a diamine containing 90 mol% or more of a diamine having a specific side chain is disclosed.
Patent Document 3 discloses a laminate of polyimide and metal foil using a diamine having a specific side chain.
Further, Patent Document 4 makes various attempts to improve the gas permeability of the polyimide film. For example, a polyimide film having improved gas permeability is disclosed by using a polyimide obtained from a diamine having a bulky trimethylsilyl group bonded to an aromatic ring.

JP-A 63-265629 Japanese Patent Laid-Open No. 2-147234 Japanese Patent Laid-Open No. 2002-361792 Japanese Patent Laid-Open No. 2004-224889

An object of the present invention is to provide a novel polyimide containing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride as an essential tetracarboxylic dianhydride component and having a high relative moisture transmission rate. is there.
Furthermore, it is providing the laminated polyimide which laminated | stacked these novel polyimides on the at least single side | surface of the heat resistant polyimide, and the metal foil laminated polyimide which laminated | stacked this laminated polyimide and metal foil.

（式中、Ａは直接結合あるいは架橋基であり、Ｒ_１〜Ｒ_４は水素原子、炭素数１〜６の炭化水素基、ヒドロキシル基、カルボキシル基、炭素数１〜６のアルコキシ基、カルボアルコキシ基から選ばれる置換基を表し、Ｒ_１及びＲ_２の少なくとも１つは水素原子ではなく、Ｒ_３及びＲ_４の少なくとも１つは水素原子ではない。） In the first aspect of the present invention, a tetracarboxylic dianhydride containing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and a diamine represented by the following general formula (1) are added in an amount of 0.5 to It is a polyimide obtained by reacting a diamine containing 40 mol%.

(In the formula, A is a direct bond or a bridging group, and R _{1 to} R ₄ are a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydroxyl group, a carboxyl group, an alkoxy group having 1 to 6 carbon atoms, and a carboalkoxy group. Represents a substituent selected from the group, and at least one of R ₁ and R ₂ is not a hydrogen atom, and at least one of R ₃ and R ₄ is not a hydrogen atom.)

The second of the present invention is a laminated polyimide obtained by laminating the first polyimide of the present invention on at least one surface of a heat-resistant polyimide.
In the third aspect of the present invention, at least one surface of the layer made of the first polyimide of the present invention, a laminated polyimide obtained by laminating a base material directly or via a heat-resistant adhesive on the first polyimide of the present invention of a laminated polyimide. Is the body.

The 1st preferable aspect of this invention is shown, These can be combined multiplely.
1) In the diamine of the general formula (1), A in the formula is a direct bond or a bridging group, and R _{1 to} R ₄ represent a substituent selected from a hydrocarbon group having 1 to 6 carbon atoms.
2) The diamine component contains paraphenylenediamine.
3) The polyimide is a polyimide obtained by heat drying (curing) at a maximum heat treatment temperature of 350 to 600 ° C.

The 2nd preferable aspect of this invention is shown, These can be combined multiplely.
1) Heat-resistant polyimide
i) Aromatic tetracarboxylic acid diesters of 7.5 to 100 mol% 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and 0 to 92.5 mol% pyromellitic dianhydride By polymerization and imidization from an anhydride component, 15-100 mol% p-phenylenediamine and 0-85 mol% 4,4'-diaminodiphenyl ether diamine component, further as required Polyimide obtained by heating and drying (curing) at a maximum heat treatment temperature of 350 to 600 ° C.,
ii) or a diamine component having a ratio (molar ratio) of 90/10 to 10/90 of an acid component of pyromellitic dianhydride and a component of 4,4′-diaminodiphenyl ether and p-phenylenediamine Is obtained by polymerizing and imidizing, and further by heating and drying (curing) at a maximum heat treatment temperature of 350 to 600 ° C. as necessary.
iii) or an aromatic tetracarboxylic acid of 7.5 to 100 mol% 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 0 to 92.5 mol% pyromellitic dianhydride It is obtained by polymerizing and imidizing a dianhydride and a diamine component containing o-tolidine or m-tolidine, and further heat-drying (curing) at a maximum heat treatment temperature of 350 to 600 ° C. as necessary. Be polyimide.

The 3rd preferable aspect of this invention is shown, These can be combined multiplely.
1) The substrate is a metal layer, preferably a layer selected from aluminum, copper and SUS.

The polyimide of the present invention is excellent in heat resistance, has a low saturated water absorption rate and a small linear expansion coefficient, and provides a polyimide having a high relative moisture transmission rate.
In addition, the polyimide of the present invention is a metal foil laminated polyimide that does not foam or peel off at high temperatures such as a solder bath with high adhesive strength by laminating directly or via an adhesive layer with a base material such as a metal foil. Can be obtained.
Since the laminate of the present invention uses the polyimide of the present invention having excellent heat resistance, a small saturated water absorption rate and a small coefficient of linear expansion, and a large relative moisture transmission rate, for example, in a high-temperature treatment process such as during production of a wiring board. , Foaming and peeling at the adhesive interface are unlikely to occur. In particular, using the polyimide of the present invention and a heat-resistant polyimide having a small relative moisture absorption rate as the polyimide core layer, the substrate such as a metal foil / the polyimide of the present invention / the heat-resistant polyimide is laminated in this order, and a high temperature such as a solder bath. Thus, it is possible to obtain a laminate such as a metal foil laminated polyimide that does not foam or peel off.

（式中、Ａは直接結合あるいは架橋基であり、Ｒ_１〜Ｒ_４は水素原子、炭素数１〜６の炭化水素基、ヒドロキシル基、カルボキシル基、炭素数１〜６のアルコキシ基、カルボアルコキシ基から選ばれる置換基を表し、Ｒ_１及びＲ_２の少なくとも１つは水素原子ではなく、Ｒ_３及びＲ_４の少なくとも１つは水素原子ではない。） The polyimide of the present invention comprises a tetracarboxylic dianhydride containing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and a diamine represented by the following general formula (1) in a range of 0.5 to A polyimide obtained by reacting a diamine containing 40 mol%, and a polyimide precursor is obtained by reacting a tetracarboxylic dianhydride and a diamine in an organic solvent to give a polyimide, and then chemical imidization or thermal imide What is obtained by making it, or what is obtained by directly imidizing by reacting tetracarboxylic dianhydride and diamine in an organic solvent or directly can be used.
In the polyimide of the present invention, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is 50 mol% or more, preferably 60 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol%. The tetracarboxylic dianhydride containing the diamine represented by the following general formula (1) is 0.5 to 40 mol%, preferably 0.7 to 30 mol%, more preferably 0.9 to 20 mol. %, Particularly preferably by reacting with 1 to 18 mol% diamine, it is possible to obtain a polyimide having excellent heat resistance, low saturated water absorption, low linear expansion coefficient, and high relative moisture transmission rate. By laminating the polyimide and the substrate directly or via an adhesive, a laminate having high adhesive strength can be obtained. The polyimide and a metal foil such as a copper foil can be directly or via an adhesive. By laminating at high temperature treatment such as 280 ° C. solder bath immersion, it is possible to obtain a foaming or peeling of the suppression or non laminate.

(In the formula, A is a direct bond or a bridging group, and R _{1 to} R ₄ are a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydroxyl group, a carboxyl group, an alkoxy group having 1 to 6 carbon atoms, and a carboalkoxy group. Represents a substituent selected from the group, and at least one of R ₁ and R ₂ is not a hydrogen atom, and at least one of R ₃ and R ₄ is not a hydrogen atom.)

  As tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, and still more preferably. Pyromellitic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, within a range that contains 80 mol% or more, particularly preferably 90 mol% or more, and does not impair the characteristics of the present invention, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) methane, bis (3 4-dicarboxyphenyl) ether, bis (3,4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxyphenyl) sulfide, p-phenylenebis (t May contain aromatic tetracarboxylic dianhydrides such as merit acid monoester acid anhydride), ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (trimellitic acid monoester acid anhydride), etc. .

In the diamine of general formula (1):
Examples of the bridging group A in the general formula (1) include an oxygen atom, a sulfur atom, a methylene group, a carbonyl group, a sulfoxyl group, a sulfone group, a 1,1′-ethylidene group, a 1,2-ethylidene group, and 2,2 ′. -Isopropylidene group, 2,2'-hexafluoroisopropylidene group, cyclohexylidene group, phenylene group, 1,3-phenylenedimethylene group, 1,4-phenylenedimethylene group, 1,3-phenylenediethylidene group 1,4-phenylenediethylidene group, 1,3-phenylenedipropylidene group, 1,4-phenylenedipropylidene group, 1,3-phenylenedioxy group, 1,4-phenylenedioxy group, biphenylenedi Oxy group, methylene diphenoxy group, ethylidene diphenoxy group, propylidene diphenoxy group, hexafluoropropylidenediphenoxy group Oxy diphenoxy group, Chiojifenokishi group, there may be mentioned a sulfonic diphenoxy group may be bonded directly without via a bridging group.

In the diamine of general formula (1):
R _{1 to} R ₄ in the general formula (1) are a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms (preferably a hydrocarbon group having 1, 2, 3, 4, 5 or 6 carbon atoms), a hydroxyl group Represents a substituent selected from a carboxyl group, an alkoxy group having 1 to 6 carbon atoms (preferably an alkoxy group having 1, 2, 3, 4, 5 or 6 carbon atoms), and a carboalkoxy group, and R ₁ and R ₂ At least one is not a hydrogen atom and at least one of R ₃ and R ₄ is not a hydrogen atom.

Examples of R _{1 to} R _{4 in} the general formula (1) include
a) R _{1 to} R ₄ are each a hydrocarbon group having 1 to 6 carbon atoms (preferably a hydrocarbon group having 1, 2, 3, 4, 5 or 6 carbon atoms), a hydroxyl group, a carboxyl group, 1 to 1 carbon atom. 6 alkoxy groups (preferably alkoxy groups having 1, 2, 3, 4, 5 or 6 carbon atoms), a combination of substituents selected from carboalkoxy groups,
b) R _{1 to} R ₃ are each a hydrocarbon group having 1 to 6 carbon atoms (preferably a hydrocarbon group having 1, 2, 3, 4, 5 or 6 carbon atoms), a hydroxyl group, a carboxyl group, 1 to 1 carbon atom. 6 is a substituent selected from an alkoxy group (preferably an alkoxy group having 1, 2, 3, 4, 5 or 6 carbon atoms), a carboalkoxy group, and only R ₄ is a combination of hydrogen atoms,
c) R ₁ and R ₃ are each a hydrocarbon group having 1 to 6 carbon atoms (preferably a hydrocarbon group having 1, 2, 3, 4, 5 or 6 carbon atoms), a hydroxyl group, a carboxyl group, 1 to 1 carbon atom. An alkoxy group having 6 carbon atoms (preferably an alkoxy group having 1, 2, 3, 4, 5 or 6 carbon atoms), a carboalkoxy group, and R ₂ and R ₄ are a combination of hydrogen atoms,
Can be mentioned.

Specific examples of R _{1 to} R _{4 in} the general formula (1) include hydrogen, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, s-butyl group, i- Hydrocarbon group such as butyl group, t-butyl group, pentyl group, cyclohexyl group, phenyl group, alkoxy group such as hydroxyl group, methoxy group, ethoxy group, propoxy group, butoxy group, carboxyl group, carbomethoxy group, carboethoxy And carboalkoxy groups such as carbopropoxy group and carbobutoxy group. R _{1 to} R ₄ may all be the same or different from each other.

As a specific example of the aromatic diamine represented by a) of the general formula (1),
3,3 ′, 5,5′-tetramethyl-4,4′-diaminobiphenyl,
3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenyl ether,
3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane,
3,3 ′, 5,5′-tetraethyl-4,4′-diaminobiphenyl,
3,3 ′, 5,5′-tetraethyl-4,4′-diaminodiphenyl ether,
3,3 ′, 5,5′-tetraethyl-4,4′-diaminodiphenylmethane,
4,4-methylene-bis (2,6-diisopropylaniline),
3,3′-dicarboxy-4,4′-diamino-5,5′-dimethyldiphenylmethane, and the like.

As a specific example of the aromatic diamine represented by c) of the general formula (1),
3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′-diaminobiphenyl, 3,3′-dihydroxy-4,4′-diaminobiphenyl, 3,3′- Dicarboxy-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl,
3,3′-dimethyl-4,4′-diaminodiphenyl ether, 3,3′-diethyl-4,4′-diaminodiphenyl ether, 3,3′-dihydroxy-4,4′-diaminodiphenyl ether, 3,3′- Dicarboxy-4,4′-diaminodiphenyl ether, 3,3′-dimethoxy-4,4′-diaminodiphenyl ether,
3,3′-dimethyl-4,4′-diaminodiphenylmethane, 3,3′-diethyl-4,4′-diaminodiphenylmethane, 3,3′-dihydroxy-4,4′-diaminodiphenylmethane, 3,3′- And dicarboxy-4,4′-diaminodiphenylmethane, 3,3′-dimethoxy-4,4′-diaminodiphenylmethane, and the like.

The diamine of the polyimide of this invention is 0.5-40 mol% of diamine represented by General formula (1), p-phenylenediamine which is diamine which is not represented by General formula (1), m-phenylenediamine, 4 , 4'-diaminodiphenylpropane, 4,4-diaminodiphenylmethane, benzidine, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl Sulfone, 4,4′-oxydianiline, 3,3′-oxydianiline, 3,4′-oxydianiline, 1,5-diaminonaphthalene, 4,4′-diaminodiphenyldiethylsilane, 4,4 ′ -Diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, 1,4-diaminobenzene (p-ph Nylenediamine), bis {4- (4-aminophenoxy) phenyl} sulfone, bis {4- (3-aminophenoxy) phenyl} sulfone, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′- Bis (3-aminophenoxy) biphenyl, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1, 99.5-60 mol% of 3-bis (3-aminophenoxy) benzene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, and the like are included.
In particular, the diamine of the polyimide of the present invention is a diamine containing 0.5 to 40 mol% of the diamine represented by the general formula (1) and 60 mol% or more of p-phenylenediamine, and further represented by the general formula (1). By using a diamine containing 0.5 to 40 mol% of diamine and 99.5 to 60 mol% of p-phenylenediamine, the heat resistance is excellent, the saturated water absorption is small, and the linear expansion coefficient is small. A polyimide having a high relative moisture transmission rate, more preferably a polyimide having a high tensile elastic modulus can be obtained.

In the polyimide of the present invention, as an example of the most excellent combination,
A tetracarboxylic acid dihydrate containing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride in an amount of 50 mol% or more, preferably 60 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more. 0.5 to 40 mol%, preferably 0.7 to 30 mol%, more preferably 0.9 to 20 mol% of anhydride and tetrasubstituted diamine represented by a) in the general formula (1) Particularly preferred examples include a combination of 1 to 18 mol% and a remaining diamine component composed of p-phenylenediamine.

In the polyimide of the present invention, in 100 mol% of the diamine component,
A) of the general formula (1) such as 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetraethyl-4,4′-diaminodiphenylmethane A 4-substituted diamine represented by
1) Preferably 0.5 to 6 mol%, more preferably 0.7 to 6 mol%, particularly preferably 1 to 6 mol%, so that the linear expansion coefficient is small, the saturated water absorption is small, and the relative permeability is low. Wet rate is large, we can obtain polyimide with excellent breaking stress, tensile elastic modulus and breaking elongation,
2) Preferably 6 to 40 mol%, more preferably 6 to 30 mol%, more preferably 7 to 20 mol%, still more preferably 9 to 17 mol%, particularly preferably 9 to 13 mol%, A polyimide having an extremely high relative moisture transmission rate, a low linear expansion coefficient, a low saturated water absorption rate, and an excellent breaking stress, tensile elastic modulus and breaking elongation can be obtained.

Polyimide can be produced by imidizing chemically or thermally from a polyimide precursor.
Any known method can be used as a method for producing a polyimide precursor. Usually, tetracarboxylic dianhydride and diamine are reacted in a substantially equimolar amount dissolved in an organic solvent and controlled. Under the same temperature conditions until the polymerization reaction of tetracarboxylic dianhydride and diamine is (substantially) complete. These polyimide precursor solutions can be usually obtained at a concentration of 1 to 35 wt%, preferably 5 to 30 wt%, and further 7 to 25 wt%, and within this range, an appropriate molecular weight and an appropriate solution viscosity can be obtained. Can do.

A known method can be used as a method for polymerizing the polyimide precursor.
A diamine component and a tetracarboxylic dianhydride that give a polyimide precursor are each polymerized in an organic solvent at a temperature of 0 to 100 ° C., preferably 5 to 50 ° C., to obtain a polyimide precursor solution (a uniform solution state). If necessary, it may be partially imidized). If necessary, multiple polyimide precursor solutions may be mixed to form a coating or film of the polyimide precursor solution, followed by drying, imidization, and heat drying By curing, polyimide can be produced. The maximum heat treatment temperature for this heat drying is preferably 350 to 600 ° C, more preferably 400 to 550 ° C, and particularly preferably 400 to 500 ° C.

As a method for producing a polyimide precursor, a known method can be used.
1) A method in which an equimolar amount of a carboxylic acid dianhydride component and a diamine component are reacted in an organic solvent, and in some cases, an acid excess or a diamine excess may be used.
2) A polyimide precursor solution A is produced by reacting the carboxylic acid dianhydride component and the diamine component represented by the general formula (1) in an organic solvent in approximately equimolar amounts, respectively, and the carboxylic acid dianhydride component in the organic solvent. And a diamine component other than the diamine represented by the general formula (1) are reacted in approximately equimolar amounts to produce a polyimide precursor solution B, and the polyimide precursor solution A and the polyimide precursor solution B are mixed. Depending on the case, it may be further polymerized. In some cases, either one may be acid-excessed and the other may be diamine-excessive.
And so on.

If it is necessary to seal the amine terminus of the polyimide precursor, dicarboxylic anhydrides such as phthalic anhydride and its substitutes (eg 3-methyl or 4-methylphthalic anhydride), hexahydrophthalic anhydride and its For example, a small amount of phthalic anhydride, such as a substituted product, succinic anhydride and its substituted product, may be added.
Moreover, the polyimide precursor solution can add an imidizing agent in the solution for the purpose of promoting imidization. For example, polyimide precursors such as imidazole, 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, benzimidazole, isoquinoline, substituted pyridine, etc. 0.05 to 10% by weight, particularly preferably 0.1 to 2% by weight, based on the weight. With these, imidization can be completed at a relatively low temperature.

  In the polyimide of the present invention, the carboxylic dianhydride component and the specific diamine component may have a block structure or a random structure.

  When forming the polyimide of the present invention into a film, a phosphorus stabilizer such as triphenyl phosphite or triphenyl phosphate is used for the purpose of limiting the gelation of the film. Can be added within a range of 0.01 to 1%.

  Organic solvents used for producing the polyimide precursor are N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, N-methylcaprolactam etc. are mentioned. These organic solvents may be used alone or in combination of two or more.

The polyimide of the present invention can produce a film having at least one of the following characteristics.
1) The saturated water absorption is 3% or less, and further 1.3 to 3%.
2) The relative moisture transmission rate is 3 or more, further 4 or more at a thickness of 25 μm.
3) The tensile elastic modulus is 400 kg / mm ² or more, further 400 kg / mm ² or more and less than 900 kg / mm ² , particularly 470 kg / mm ² or more and less than 900 kg / mm ² .
4) The linear expansion coefficient (25 μm thickness) is 10 to 40 × 10 ⁻⁶ cm / cm / ° C., more preferably 12 to 30 × 10 ⁻⁶ cm / cm / ° C., and particularly 12 to 25 × 10 ⁻⁶ cm / cm / ° C. Must be in ° C.

The polyimide of the present invention can be applied to any of a coating agent and a film (a non-cured film is heat-treated using a pin tenter and substantially stretched).
When the polyimide of the present invention is applied to a film, the thickness of the film is about 3 to 200 μm, and when applied as a coating agent, the thickness is about 0.1 to 2 μm.

  The polyimide of the present invention can also be applied as a modified polyimide layer as a surface layer of a core layer made of heat-resistant polyimide. In this case, a polyimide precursor solution that gives a polyimide core layer made of heat-resistant polyimide is cast on a support and dried to form a self-supporting film, and the polyimide precursor solution that gives the polyimide of the present invention on one side thereof Is applied or sprayed so that the thickness after drying is about 0.1 to 2 μm, dried, and if necessary, the thickness after drying the polyimide precursor solution on the other side is about 0.1 to 2 μm At least one side is improved by applying or spraying so as to become, drying, heating to remove the solvent and imidization, and if necessary, heat drying (curing) at a maximum heat treatment temperature of 350 to 600 ° C. A quality laminated polyimide film can be produced. The laminated polyimide film preferably has a thickness of about 5 to 150 μm, particularly about 10 to 125 μm.

As polyimide of heat resistant polyimide layer of laminated polyimide film,
i) Aromatic tetracarboxylic acid diesters of 7.5 to 100 mol% 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and 0 to 92.5 mol% pyromellitic dianhydride By polymerization and imidization from an anhydride component, 15-100 mol% p-phenylenediamine and 0-85 mol% 4,4'-diaminodiphenyl ether diamine component, further as required Polyimide obtained by heating and drying (curing) at a maximum heat treatment temperature of 350 to 600 ° C.,
ii) or a diamine component having a ratio (molar ratio) of 90/10 to 10/90 of an acid component of pyromellitic dianhydride and a component of 4,4′-diaminodiphenyl ether and p-phenylenediamine Is obtained by polymerizing and imidizing, and further by heating and drying (curing) at a maximum heat treatment temperature of 350 to 600 ° C. as necessary.
iii) or an aromatic tetracarboxylic acid of 7.5 to 100 mol% 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 0 to 92.5 mol% pyromellitic dianhydride It is obtained by polymerizing and imidizing a dianhydride and a diamine component containing o-tolidine or m-tolidine, and further heat-drying (curing) at a maximum heat treatment temperature of 350 to 600 ° C. as necessary. Examples thereof include polyimide.

A laminate having a substrate on at least one side by laminating at least one side of the polyimide of the present invention and the substrate directly or via an adhesive by pressurization or pressure heating (laminate method). Can be manufactured.
A laminate can be produced by forming a metal layer film on at least one surface of the polyimide of the present invention using a thin film deposition method and an electroplating method.
Moreover, it can obtain also by casting the polyimide precursor solution which gives the polyimide of this invention on base materials, such as metal foil, and completing imidation by chemically or heat-drying.

By laminating the polyimide layer of the present invention and the base material of the laminated polyimide film of the present invention, either directly or via an adhesive, by pressurization or pressure heating (laminate method), at least on one side. A laminate having a material can be produced.
A laminated body can be manufactured by forming a metal layer film on the polyimide layer side of the present invention of the laminated polyimide film using a thin film deposition method and an electroplating method.

  In the laminating method, a laminate can be obtained by providing a heat-resistant adhesive layer on one side or both sides of the polyimide film of the present invention, further superposing metal foil, heating and pressing. The heat-resistant adhesive is not particularly limited as long as it is a heat-resistant adhesive used in the electronic field. For example, a polyimide-based adhesive, an epoxy-modified polyimide-based adhesive, a phenol resin-modified epoxy resin adhesive, an epoxy Examples thereof include a modified acrylic resin adhesive and an epoxy-modified polyamide adhesive. This heat-resistant adhesive layer can be provided by any method which is itself implemented in the electronic field. For example, an adhesive solution may be applied to the polyimide film or the molded body and dried, or formed separately. It may be laminated with a film adhesive.

As the substrate, a single metal or alloy, for example, copper, aluminum, gold, silver, nickel, stainless steel foil, metal plating layer (preferably vapor deposition metal underlayer-metal plating layer or chemical metal plating layer, etc. Many known techniques can be applied.), And rolled copper foil, electrolytic copper foil, copper plating layer and the like are preferable. The thickness of the metal foil is not particularly limited, but is preferably 0.1 μm to 10 mm, more preferably 1 to 50 μm, and particularly preferably 5 to 18 μm.
The laminate may be formed by bonding another base material such as a ceramic, a glass substrate, a silicon wafer, the same or different metal, or a polyimide film with a heat resistant adhesive.

  According to a preferred embodiment of the present invention, even when the laminate is subjected to a high-temperature treatment such as a solder bath at 280 ° C. or the like, foaming and peeling at the adhesion interface hardly occur.

  The laminate can be suitably used as an electronic component substrate and a wiring substrate, and can be suitably used as, for example, a printed circuit board, a power circuit board, a flexible heater, and a resistor board. Further, it is useful for applications such as an insulating film and a protective film formed on a material having a small linear expansion coefficient such as a base material such as LSI.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

(Evaluation of film characteristics)
1) Saturated water absorption (%): The polyimide film was dried to a constant weight in a dry nitrogen atmosphere, the film weight at the time of drying was measured, and then immersed in pure water at 23 ° C. for 24 hours. After wiping off, the film weight at the time of water absorption was measured, and the saturated water absorption was calculated according to the formula (1).

2) Relative moisture permeation rate: The obtained polyimide film was dried to a constant weight in a dry nitrogen atmosphere, and the film weight at the time of drying was measured. Thereafter, the dried polyimide film was measured at a temperature of 27 ° C. and a humidity of 55% RH. The change in weight was traced for 1 hour in the atmosphere, the initial weight increase rate (the slope of the weight change curve) was taken as the moisture transmission rate, and the relative value with the moisture transmission rate of the 50 μ film in Comparative Example 2 as 1 was measured as relative permeability. The wet speed was used.

3) Linear expansion coefficient: measured using TMA-50 in the range of 5 ° C / min and 100 ° C to 250 ° C.

4) Mechanical properties (breaking stress, tensile modulus, breaking elongation): Measured according to ASTM D882 using a polyimide film with a film thickness of 25 μm. The measurement conditions were performed using TENSILON in an environment of a pulling speed of 2 mm / min, a temperature of 23 ° C., and a humidity of 55%. The measurement is performed on 5 samples, and the measurement result is an average value of 5 samples.

5) Adhesive strength: on the obtained polyimide film, an acrylic adhesive (Pyralax) manufactured by DuPont Co., Ltd., rolled copper foil (BHY-13H-T foil manufactured by Nikko Material Co., Ra: 0.18 μm) are superimposed, The laminate was obtained by pressing with a press at 180 ° C. and 30 kgf / cm ² for 1 minute and further heat treating at 180 ° C. for 60 minutes. The 90-degree peel strength at the interface of this laminate was measured in accordance with JIS C6471-8.1 to obtain the adhesive strength.

6) Glass transition temperature: Dynamic viscoelasticity was measured in the range of room temperature to 500 ° C. using a dynamic viscoelasticity measuring device RSAIII.

(Synthesis example 1 of raw material dope)
N, N-dimethylacetamide (DMAc) was added to the reaction vessel, paraphenylenediamine (PPD) was added under stirring and nitrogen flow, and the mixture was kept at 50 ° C. and completely dissolved. To this solution, gradually add 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) in an equimolar amount of the diamine component and the dicarboxylic acid component while paying attention to heat generation. After completion, the reaction was continued for 3 hours while maintaining 50 ° C. to obtain a polyimide precursor solution having a monomer concentration of 18% by mass (yellow viscous liquid, solution viscosity at 25 ° C. was about 1000 poise). This solution is referred to as the first liquid.

(Synthesis example 2 of raw material dope)
Except for adding 3,3′-dicarboxy-4,4′-diaminodiphenylmethane (MBAA) in place of PPD, the same reaction as in Synthesis Example 1 was performed to obtain a polyimide precursor solution having a monomer concentration of 18% by mass ( A light brown viscous liquid, the solution viscosity at 25 ° C. was about 500 poise). This solution is referred to as the second liquid.

(Synthesis example 3 of raw material dope)
A polyimide precursor solution having a monomer concentration of 18% by mass was prepared by performing the same reaction as in Synthesis Example 1 except that 4,4′-methylene-bis (2,6-dimethylaniline) (MDX) was added instead of PPD. (Light brown viscous liquid, solution viscosity at 25 ° C. is about 1000 poise). This solution is referred to as the third liquid.

(Synthesis example 4 of raw material dope)
The same reaction as in Synthesis Example 1 was performed except that 4,4′-methylene-bis (2-methylaniline) (MDT) was added instead of PPD, and a polyimide precursor solution (concentrated) having a monomer concentration of 18% by mass was obtained. A red viscous liquid having a solution viscosity of about 1000 poise at 25 ° C. was obtained. This solution is referred to as the fourth liquid.

(Synthesis example 5 of raw material dope)
The same reaction as in Synthesis Example 1 was performed except that 3,3′-dimethoxy-4,4′-diaminobiphenyl (DANS) was added instead of PPD, and a polyimide precursor solution having a monomer concentration of 18% by mass (light A black-brown viscous liquid having a solution viscosity at 25 ° C. of about 1500 poise) was obtained. This solution is referred to as the fifth solution.

(Synthesis Example 6 of raw material dope)
Except for adding 3,3′-dimethyl-4,4′-diaminobiphenyl (TB) instead of PPD, the same reaction as in Synthesis Example 1 was carried out to obtain a polyimide precursor solution (light-weighted) with a monomer concentration of 18% by mass. A brown viscous liquid, the solution viscosity at 25 ° C. was about 800 poise). This solution is referred to as the sixth liquid.

  When the film is produced by casting on a substrate, the obtained film surface has a substrate side and an air side, the air side surface of the film is represented as A surface, and the substrate side surface is represented as B surface.

( Examples 2 and 3, Reference Examples 1 to 4 , Comparative Example 1)
The first liquid and the second to sixth liquids are mixed at a ratio shown in Table 1, and coated on a glass substrate so as to have a final film thickness of about 25 μm, and heated at 135 ° C. for 3 minutes to form a solidified film, After peeling from the glass substrate, it was attached to a pin tenter and heated at 130 ° C. for 5 minutes, 180 ° C. for 5 minutes, 210 ° C. for 5 minutes, 320 ° C. for 2 minutes, and then heated to 450 ° C. in 5 minutes. A polyimide film was obtained by heat-treating at 2 ° C. for 2 minutes. Using this polyimide film, the water absorption rate and relative moisture transmission rate were measured, and the results are shown in Table 1.
Furthermore, the glass transition temperature of this polyimide film was measured. None of these films showed a clear glass transition point below 450 ° C.

Further, on the A side or B side of the obtained polyimide film, an acrylic adhesive (Pyralax) manufactured by DuPont Co., Ltd., rolled copper foil (BHY-13H-T foil manufactured by Nikko Materials Co., Ra: 0.00). 18 μm), and heat-pressed with a press at 180 ° C. and 30 kgf / cm ² for 1 minute, followed by heat treatment at 180 ° C. for 60 minutes, and three layers (polyimide film A surface / adhesive / copper foil) , (Polyimide film B surface / adhesive / copper foil) were obtained. The 90 ° peel strength of these laminates was measured, and the results are shown in Table 1.

(Examples 7 to 13 and Comparative Examples 2 to 4)
The first liquid and the third liquid are mixed at a ratio shown in Table 2, and are applied onto a glass substrate so as to have a final film thickness of 25 μm and 50 μm. (Film thickness 50 μm) Heated to form a solidified film, peeled off from the glass substrate, and then attached to a pin tenter and heated at 130 ° C. for 5 minutes, 180 ° C. for 5 minutes, 210 ° C. for 5 minutes, and 320 ° C. for 2 minutes Then, the temperature was raised to 450 ° C. in 5 minutes, and the polyimide film was obtained by heat-treating at 450 ° C. for 2 minutes.
The resulting polyimide film was measured for saturated water absorption, relative moisture transmission rate, linear expansion coefficient, and mechanical properties (breaking stress, tensile modulus, breaking elongation), and the results are shown in Table 2.

(Example 14)
The first liquid is applied on a glass substrate to a final film thickness of about 21 μm, and heated at 135 ° C. for 3 minutes to form a solidified film (substrate layer: heat-resistant polyimide). The first liquid, the third liquid, The polyimide precursor solution (diamine component is MDX 10 mol% and PPD 90 mol%) prepared to a monomer concentration of 5 wt% by mixing and coating on the A side of the solidified film to a final film thickness of 2 μm, After heating at 135 ° C. for 1 minute, it was peeled off from the glass substrate, similarly applied to the B side of the solidified film, and further heated at 135 ° C. for 1 minute. Next, it is attached to a pin tenter, heated at 130 ° C. for 5 minutes, 180 ° C. for 5 minutes, 210 ° C. for 5 minutes, and 320 ° C. for 2 minutes, then heated to 450 ° C. in 5 minutes, and then heated to 450 ° C. for 2 minutes. By carrying out heat treatment while maintaining the minute, a three-layer polyimide film having a thickness of 2 μm / 21 μm / 2 μm was obtained.
The saturated water absorption rate and relative moisture transmission rate of the obtained three-layer polyimide film were measured, and the results are shown in Table 3. Further, on the substrate layer A surface side or the substrate layer B surface side of the obtained three-layer polyimide film, acrylic adhesive (Pyralax) manufactured by DuPont Co., Ltd., rolled copper foil (BHY-13H-T foil manufactured by Nikko Materials Co., Ltd.) , Ra: 0.18 μm), heat-pressed with a press at 180 ° C. and 30 kgf / cm ² for 1 minute, and further heat-treated at 180 ° C. for 60 minutes, and the A side of the heat-resistant polyimide (substrate layer) Two types of four-layer laminates were obtained: / polyimide / adhesive / copper foil, or B side of heat-resistant polyimide (substrate layer) / polyimide / adhesive / copper foil. The 90 ° peel strength of this laminate was measured and the results are shown in Table 3.

(Example 15)
The same evaluation as in Example 14 was performed except that the coating thickness was adjusted so that the thickness of each layer of the three-layer polyimide film was 1 μm / 10 μm / 1 μm. The results are shown in Table 3.

(Example 16)
The same evaluation as in Example 15 was performed, except that a substrate layer was formed using a solution obtained by adding 1,2-dimethylimidazole to the first solution in an amount of 2% by weight based on the polyimide precursor. The results are shown in Table 3.

(Comparative Example 5)
The same evaluation as in Example 15 was carried out except that only a substrate layer having a thickness of 12 μm was formed using a solution obtained by adding 1,2-dimethylimidazole to the polyimide precursor in an amount of 2% by weight. went. The results are shown in Table 3.

(Evaluation of high temperature treatment)
For the laminates obtained in Examples 2 and 3, Reference Examples 1 to 4 , Comparative Example 1, Examples 14 to 16, and Comparative Example 5, foaming and peeling at the bonding interface by the high-temperature treatment step were performed by the following evaluation method. The occurrence was evaluated.
Evaluation method: A laminate having one surface bonded to copper foil is immersed in pure water at 23 ° C. for 24 hours, wiped off the adhering water, and then immersed in a solder bath at 280 ° C. for 10 seconds to visually check foaming and peeling of the laminate. And observe the results.
In Examples 2 and 3, Reference Examples 1 to 3 and Examples 14 to 16, foaming and peeling were not observed.
In Reference Example 4 , slight foaming was observed.
In Comparative Examples 1 and 5, foaming and peeling were observed.
It has been found that the laminate obtained from the polyimide of the present invention hardly foams or peels even when subjected to high temperature treatment.

Claims (3)

  Mixing a tetracarboxylic dianhydride containing 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and a diamine containing paraphenylenediamine to obtain a first polyimide precursor solution;
Tetracarboxylic dianhydride including 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-methylene-bis (2,6-dimethylaniline) are mixed to form a second Obtaining a polyimide precursor solution;
Mixing the first polyimide precursor solution and the second polyimide precursor solution to form a solidified film;
Heat treating the solidified film;
The manufacturing method of the polyimide film containing this.   Casting a first polyimide precursor solution that gives a polyimide core layer made of heat-resistant polyimide onto a support and drying to form a self-supporting film;
Tetracarboxylic dianhydride including 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-methylene-bis (2,6-dimethylaniline) are mixed to form a second Preparing a polyimide precursor solution;
A step of preparing a third polyimide precursor solution by mixing a tetracarboxylic dianhydride containing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and a diamine containing paraphenylenediamine; ,
Mixing the second polyimide precursor solution and the third polyimide precursor solution;
Applying or spraying the mixed polyimide precursor solution on at least one side of the self-supporting film; and
Heating and drying the coated or sprayed self-supporting film;
A method for producing a laminated polyimide film comprising:   The first polyimide precursor solution is a mixture of a tetracarboxylic dianhydride containing 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and a diamine containing paraphenylenediamine. The manufacturing method of the laminated polyimide film of description.