JP7222089B2 - Resin film, metal-clad laminate and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a highly transparent resin film (insulating resin layer) having excellent heat resistance, adhesiveness and flexibility, and a metal-clad laminate obtained by laminating the same.

Polyimide is a heat-resistant resin obtained by ring closure reaction of polyamic acid synthesized by condensation reaction of tetracarboxylic anhydride and diamine as raw materials. It has excellent resistance to thermal decomposition, high resistance to chemical changes such as oxidation or hydrolysis, and excellent flexibility, mechanical and electrical properties. Polyimide is widely used for insulating resin layers of flexible printed circuit boards (FPCs) generally used in electronic devices.

The insulating resin layer in commercially available copper-clad laminates generally used for FPC consists of a wholly aromatic polyimide resin and exhibits a yellowish brown color due to the formation of intramolecular and intermolecular charge transfer complexes, which is colorless. It is difficult to apply to transparent FPC applications that require transparency.

In order to make polyimide colorless and transparent, it has been proposed to suppress the formation of intramolecular and intermolecular charge-transfer complexes by using an alicyclic diamine or an alicyclic acid anhydride as a diamine component. For example, Patent Document 1 proposes a colorless and transparent semi-alicyclic polyimide formed from an alicyclic diamine and an aromatic acid dianhydride, and Patent Document 2 proposes an alicyclic diamine and an alicyclic A colorless and transparent wholly alicyclic polyimide composed of an acid anhydride has been proposed. However, the resulting polyimides all have a glass transition temperature of about 280° C. or less, and their heat resistance is insufficient, making it difficult to apply them to the main components as an insulating layer of FPC. Moreover, since colorless and transparent polyimide suppresses the formation of a charge-transfer complex, there is also a problem that it is difficult to satisfy the low thermal expansion property required for FPC.

Patent Document 3 and Patent Document 4 disclose a laminate of metal and polyimide with a fluorinated polyimide as an insulating resin layer, but the laminate shown here focuses on the transparency of the insulating layer. Although it has excellent transparency, the control of the thermal expansion coefficient and other properties of the insulating layer is insufficient, and the adhesive strength with the smooth metal layer is low, making it suitable for FPC applications. It was not something that fully satisfies the characteristics as.

Patent Document 5 has transparency and aims to improve adhesive strength with a smooth metal layer, but the polyimide that adheres to the metal layer is still colored, and the transparency of the entire polyimide layer is poor. The properties of the metal-clad laminate suitable for transparent FPC applications were not fully satisfied.

Metal-clad laminates used in FPCs are composed of a thin metal foil and an insulating resin layer containing a polyimide layer. This causes problems such as curling and dimensional changes when mounting electronic components, making accurate mounting impossible. On the other hand, a metal-clad laminate having an insulating resin layer with excellent transparency has excellent visibility from the insulating resin layer side when a semiconductor element is mounted on a wiring board. It is advantageous for light irradiation from the insulating resin layer side in the case of joining a semiconductor element by using a thin film, and is expected to be used for transparent FPC.

JP-A-7-10993 Japanese Patent Application Laid-Open No. 2008-163210 JP-A-4-47933 JP-A-2000-198842 JP 2010-155360 A

An object of the present invention is to provide a resin film and a metal-clad laminate for a wiring board which have excellent heat resistance, dimensional stability represented by a coefficient of thermal expansion, flexibility, adhesiveness, and high transparency. be.

As a result of repeated studies to solve the above problems, the present inventors have found that by using a specific polyimide for the insulating resin layer of the wiring board laminate or FPC and having an appropriate layer structure, the thickness of the polyimide layer The inventors have found that the above problems can be solved by controlling specific physical properties, and have completed the present invention.

［式（１）中、Ｘは単結合、－Ｏ－、又は－Ｃ（ＣＦ_３）_２－から選ばれる２価の基を示す。］

［式（２）中、Ｒは独立に、ハロゲン原子、又は炭素数１～６のハロゲン原子で置換されてもよいアルキル基若しくはアルコキシ基、又は炭素数１～６の１価の炭化水素基若しくはアルコキシ基で置換されてもよいフェニル基若しくはフェノキシ基を示し、Ｚは独立に－Ｏ－、－Ｓ－、－ＣＨ_２－、－ＣＨ(ＣＨ_３)－、－Ｃ(ＣＨ_３)_２－、－ＣＯ－、－ＣＯＯ－、－ＳＯ_２－、－ＮＨ－又は－ＮＨＣＯ－から選ばれる２価の基を示し、ｎ_１は０～３の整数、ｎ_２は０～４の整数を示す。］That is, the present invention provides a resin film having a plurality of polyimide layers,
conditions a and b below;
a) the thickness is in the range of 5 μm or more and 200 μm or less;
b) having a total light transmittance of 80% or more;
The filling,
At least one of the polyimide layers contains a polyimide layer (P1),
The polyimide constituting the polyimide layer (P1) contains an acid anhydride residue derived from an acid anhydride component and a diamine residue derived from a diamine component,
The polyimide contains 50 mol% or more of an acid anhydride residue derived from an aromatic tetracarboxylic acid anhydride represented by the following general formula (1) with respect to all acid anhydride residues, and all diamine A resin film containing 50 mol % or more of a diamine residue derived from an aromatic diamine compound represented by the following general formula (2) based on the residue.

[In formula (1), X represents a divalent group selected from a single bond, —O—, and —C(CF ₃ ) ₂ —. ]

[In the formula (2), R is independently a halogen atom, an alkyl group or an alkoxy group optionally substituted with a halogen atom having 1 to 6 carbon atoms, or a monovalent hydrocarbon group having 1 to 6 carbon atoms, or represents a phenyl group or a phenoxy group which may be substituted with an alkoxy group, and Z is independently -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, represents a divalent group selected from --CO--, --COO--, --SO ₂ --, --NH-- or --NHCO--, where _n1 is an integer of 0-3 and _n2 is an integer of 0-4; ]

In the resin film of the present invention, the polyimide layer (P1) is preferably positioned as the outermost layer.

In addition to the conditions a and b, the resin film of the present invention preferably satisfies the condition c) that the coefficient of thermal expansion (CTE) is in the range of 10 ppm/K or more and 30 ppm/K or less.

In the resin film of the present invention, the polyimide layer (P1) preferably accounts for 1% or more and less than 50% of the total thickness.

Moreover, the resin film of the present invention preferably satisfies condition d) that HAZE is 5% or less in addition to conditions a and b.

In addition to the conditions a and b, the resin film of the present invention preferably satisfies condition e) that YI is 10 or less when the thickness is 10 μm.

In addition to the conditions a and b, the resin film of the present invention preferably satisfies the condition f) that when the thickness is 50 μm, YI is 30 or less.

［一般式（Ａ１）中、置換基Ｘは独立にフッ素原子で置換されている炭素数１～３のアルキル素基を示し、ｍ及びｎは独立に１～４の整数を示す。］Further, in the resin film of the present invention, the polyimide constituting the main layer of the polyimide layer is a diamine residue derived from an aromatic diamine compound containing a fluorine atom and / or an aromatic tetracarboxylic acid anhydride containing a fluorine atom. It is preferred to include an anhydride residue derived from The polyimide constituting the main layer of the polyimide layer contains 50 mol% or more of diamine residues derived from a diamine compound represented by the following general formula (A1) with respect to all diamine residues. is preferred.

[In the general formula (A1), the substituent X independently represents an alkyl group having 1 to 3 carbon atoms and is substituted with a fluorine atom, and m and n independently represent an integer of 1 to 4. ]

The present invention provides a metal-clad laminate comprising an insulating resin layer having a plurality of polyimide layers and a metal layer laminated on at least one surface of the insulating resin layer,
The metal-clad laminate is characterized in that the insulating resin layer is made of the resin film.

In the metal-clad laminate of the present invention, it is preferable that the polyimide layer (P1) of the insulating resin layer in contact with the metal layer is the polyimide layer (P1).

Further, in the metal-clad laminate of the present invention, it is preferable that the thickness of the metal layer is in the range of 1 μm or more and 20 μm or less.

In the metal-clad laminate of the present invention, it is preferable that the ten-point average roughness Rzjis of the surface of the metal layer in contact with the insulating resin layer is in the range of 0.01 μm or more and 0.5 μm or less.

Further, in the metal-clad laminate of the present invention, it is preferable that the 180° peel strength between the insulating resin layer and the metal layer is 0.5 kN/m or more.

The metal-clad laminate of the present invention is
A metal-clad laminate comprising an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer,
The insulating resin layer is composed of a single-layer or multiple-layer polyimide layer, and the following conditions a to g;
a) the thickness is in the range of 5 μm or more and 20 μm or less;
b) a coefficient of thermal expansion (CTE) within the range of 10 ppm/K or more and 30 ppm/K or less;
c) having a total light transmittance of 80% or more;
d) YI is 10 or less;
e) HAZE is 3% or less;
f) having a glass transition temperature (Tg) of 280° C. or higher;
g) a tensile strength of 100 MPa or more;
is characterized by satisfying

The method for producing a metal-clad laminate of the present invention is for producing a metal-clad laminate comprising an insulating resin layer having a plurality of polyimide layers and a metal layer laminated on at least one surface of the insulating resin layer. a method,
The insulating resin layer is made of the resin film according to claim 1,
It is characterized by including a step of superimposing the surface of the polyimide layer (P1) of the resin film and the metal layer and bonding them by thermocompression.

Since the resin film and metal-clad laminate of the present invention have excellent heat resistance, dimensional stability, adhesiveness, flexibility and high transparency, they are particularly suitable as insulating materials for manufacturing electronic components such as FPCs. It is suitable for use in transparent FPCs that require colorless transparency for mounting semiconductor elements. In addition, the resin film and metal-clad laminate of the present invention can also be applied to display devices such as liquid crystal display devices, organic EL display devices, touch panels, color filters, and electronic paper, and their component parts.

The resin film of the present invention will be described below.
From the viewpoint of transparency, the resin film of the present invention must have a thickness in the range of 5 μm or more and 200 μm or less and must have a total light transmittance of 80% or more in the visible region.

Moreover, by having a plurality of polyimide layers, it is possible to provide a resin film that is excellent not only in transparency but also in various physical properties such as heat resistance, adhesiveness, and flexibility. The plurality of polyimide layers may have a two-layer structure of a polyimide layer (P1) and another polyimide layer, preferably three layers, and the polyimide layer (P1) may be arranged as an outer layer. More preferably, of the three layers, two outer layers excluding the inner layer are both polyimide layers (P1). For example, when forming a plurality of polyimide layers by a casting method, it may be a two-layer structure in which the polyimide layer (P1) and the polyimide layer other than the polyimide layer (P1) are laminated in this order from the cast surface side. A three-layer structure in which a polyimide layer (P1), a polyimide layer other than the polyimide layer (P1), and the polyimide layer (P1) are laminated in this order from the cast surface side may be employed. As used herein, the term "cast surface" refers to the surface facing the support when the polyimide layer is formed. The support may be a metal layer of a metal-clad laminate, or may be a support for forming a gel film or the like. The surface opposite to the cast surface of the polyimide layers is described as a "laminate surface", but unless otherwise specified, the laminate surface may or may not have a metal layer laminated thereon.

In the resin film of the present invention, the polyimide constituting the polyimide layer (P1) is preferably a thermoplastic polyimide. Application as an adhesive layer is preferred. Therefore, the most preferred embodiment is a resin film having a polyimide layer (P1) on its surface layer.

A preferred embodiment of the resin film of the present invention has a thermoplastic polyimide layer (P1) and a non-thermoplastic polyimide layer composed of a non-thermoplastic polyimide, and at least one of the non-thermoplastic polyimide layers It is preferable to have a polyimide layer (P1) to be a thermoplastic polyimide layer. That is, the polyimide layer (P1) is preferably provided on one side or both sides of the non-thermoplastic polyimide layer.

Also, the non-thermoplastic polyimide layer constitutes a low thermal expansion polyimide layer, and the thermoplastic polyimide layer constitutes a high thermal expansion polyimide layer. Here, the low thermal expansion polyimide layer preferably has a coefficient of thermal expansion (CTE) in the range of 1 ppm/K or more and 25 ppm/K or less, more preferably 3 ppm/K or more and 25 ppm/K or less. say. Further, the high thermal expansion polyimide layer preferably has a CTE of 35 ppm/K or more, more preferably 35 ppm/K or more and 80 ppm/K or less, still more preferably 35 ppm/K or more and 70 ppm/K or less. layer. The polyimide layer can be made into a polyimide layer having a desired CTE by appropriately changing the combination of raw materials to be used, thickness, and drying/curing conditions.
Here, non-thermoplastic polyimide generally refers to polyimide that does not soften or exhibit adhesiveness when heated. A polyimide having a storage modulus of 1.0×10 ⁹ Pa or more at 360° C. and a storage modulus of 1.0×10 ⁸ Pa or more at 360° C. In addition, thermoplastic polyimide is generally a polyimide whose glass transition temperature (Tg) can be clearly confirmed. In the present invention, the storage modulus at 30 ° C. measured using DMA is 1.0 × 10 ⁹ Pa and a storage modulus at 360° C. of less than 1.0×10 ⁸ Pa.

The CTE of the resin film of the present invention is preferably in the range of 10 ppm/K or more and 30 ppm/K or less. By controlling the thickness within such a range, deformation such as curling can be suppressed, and high dimensional stability can be ensured. Here, CTE is the average value of thermal expansion coefficients in the length direction (MD direction) and width direction (TD direction) of the resin film.

The thickness of the entire polyimide layer is in the range of 5 µm to 200 µm, and the thickness of each layer is preferably in the range of 7 µm to 50 µm for the inner layer and 1 µm to 5 µm for the outer layer. More preferably, the inner layer has a thickness of 7 μm or more and 20 μm or less, and the outer layer has a thickness of 1 μm or more and 3 μm or less. From another point of view, the thickness of the outer layer is preferably in the range of 1% or more and less than 50%, more preferably in the range of 1% or more and 20% or less of the total thickness of the polyimide layer.

From the viewpoint of transparency, the resin film of the present invention has a total light transmittance of 80% or more in the visible region. Also, the light transmittance at a wavelength of 450 nm is preferably 70% or more, more preferably 80% or more. For example, it is preferable that the thickness of the entire resin film is 20 μm. More preferably, the total light transmittance is 85% or more. By controlling the content within such a range, white turbidity due to reflection and scattering of light in the resin film is suppressed, and excellent transparency is obtained. If the total light transmittance is less than 80%, the turbidity increases and the transparency of the resin film decreases.

The resin film of the present invention preferably has a HAZE (turbidity) of 5% or less, more preferably 2% or less. If the HAZE exceeds 5%, for example, light scattering tends to occur. In addition, HAZE depends on the surface profile of the resin film, and even a low-profile resin film has a polyimide layer (P1), so it is possible to achieve both adhesive strength and transparency. It can be suitably used for laminating a circuit board or a glass base material.

Moreover, when the thickness of the resin film of the present invention is 10 μm, the YI (yellowness index) is preferably 10 or less. Moreover, when the thickness of the resin film of the present invention is 50 μm, YI is preferably 30 or less. By controlling the content within such a range, the resin film can be made nearly colorless. On the other hand, when the YI is out of the above range, the yellow or yellowish brown coloring becomes strong, and the visibility of the resin film is lowered.

The polyimide layer is made of polyimide containing an acid anhydride residue and a diamine residue, and the polyimide constituting at least one polyimide layer (P1) contains all acid anhydride residues derived from the acid anhydride component. , contains 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more of the acid anhydride residue derived from the aromatic tetracarboxylic anhydride represented by the general formula (1) By setting it in such a range, heat resistance and low retardation can be easily exhibited. Further, the polyimide contains 50 mol % or more of diamine residues derived from the aromatic diamine compound represented by the general formula (2) with respect to all diamine residues contained in the polyimide. and preferably 70 mol % or more, more preferably 90 mol % or more. In the prior art, if the content of the aromatic diamine compound represented by the general formula (2) is large, the alignment of the polymer chains of the polyimide is disturbed, and the optical properties and thermal properties may be greatly reduced. However, the present inventors have found that a polyimide having a specific composition containing a certain amount or more of the diamine exhibits low retardation while ensuring general optical properties and thermal properties. is heading. Here, low retardation means that the retardation in the thickness direction is 200 nm or less at a thickness of 10 μm.

The aromatic tetracarboxylic anhydride represented by the general formula (1) imparts flexibility to the polyimide and reduces interactions such as π-π stacking between polymer chains, resulting in It is believed that the resulting polyimide can be made nearly colorless and transparent because charge transfer (CT) between the group and the aromatic diamine residue is less likely to occur. Further, the aromatic diamine compound represented by the general formula (2) has two or more benzene rings, and has an amino group and a divalent linking group Z directly attached to at least two benzene rings, so that the polyimide molecule The degree of freedom of the chains is increased, resulting in high flexibility, which is thought to contribute to the improvement of the flexibility of the polyimide molecular chains and promote the enhancement of toughness. In the present invention, the acid anhydride residue represents a tetravalent group derived from a tetracarboxylic dianhydride, and the diamine residue represents a divalent group derived from a diamine compound. represents

The acid anhydride residue contained in the polyimide constituting the polyimide layer (P1) is an acid anhydride residue derived from the aromatic tetracarboxylic acid anhydride represented by general formula (1).

In formula (1), X represents a divalent group selected from a single bond, —O—, and —C(CF ₃ ) ₂ —.

Examples of the aromatic tetracarboxylic anhydride represented by formula (1) include 4,4'-oxydiphthalic dianhydride (ODPA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride. (BPDA), 2,2-bis(3,4-dicarboxyphenyl)-hexafluoropropane dianhydride (6FDA). These aromatic tetracarboxylic anhydrides are preferable because they can impart strength and flexibility to the polyimide film, are excellent in heat resistance and transparency, and can control the CTE within an appropriate range. Among these, ODPA and 6FDA are particularly preferred.

The diamine residue contained in the polyimide constituting the polyimide layer (P1) is a diamine residue derived from the aromatic diamine compound represented by general formula (2).

In formula (2), Z is independently -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -CO-, -COO-, -SO ₂ represents a divalent group selected from -, -NH- or -NHCO-, preferably -O-. _n2 represents an integer of 0 to 4, preferably 0 or 1;
R is a substituent and is independently a halogen atom, an alkyl group or alkoxy group optionally substituted with a halogen atom having 1 to 6 carbon atoms, or a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms; represents a phenyl group or phenoxy group which may be substituted with _n1 independently represents an integer of 0 to 3, preferably 0 or 1; Here, "independently" means that the plurality of substituents R, divalent group Z, and integer _n1 may be the same or different in the above formula (2). In the above formula (2), the hydrogen atoms in the two terminal amino groups may be substituted, for example -NR ₃ R ₄ (wherein R ₃ and R ₄ are independently alkyl groups, etc.). meaning any substituent). The same applies to other diamine compounds.
However, in general formula (1), when X is a single bond, in formula (2), Z is independently -O-, -S-, -CH ₂ -, -CH(CH ₃ )- or -NH - represents a divalent group selected from;

Examples of aromatic diamine compounds represented by formula (2) include 3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl Sulfone, 3,3-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylpropane, 3,4'-diaminodiphenyl sulfide, 3,4'-diaminobenzophenone , (3,3′-bisamino)diphenylamine, 1,4-bis(3-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene (APB), 1,3-bis(4-aminophenoxy ) Benzene (TPE-R), 3-[4-(4-aminophenoxy)phenoxy]benzenamine, 3-[3-(4-aminophenoxy)phenoxy]benzenamine, 4,4'-[2-methyl- (1,3-phenylene)bisoxy]bisaniline, 4,4'-[4-methyl-(1,3-phenylene)bisoxy]bisaniline, 4,4'-[5-methyl-(1,3-phenylene)bisoxy ]bisaniline, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-( 3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)]benzophenone, bis[4,4'-(3-aminophenoxy)] Benzanilide, 4-[3-[4-(4-aminophenoxy)phenoxy]phenoxy]aniline, 4,4'-[oxybis(3,1-phenyleneoxy)]bisaniline, bis[4-(4-aminophenoxy) phenyl]ether (BAPE), bis[4-(4-aminophenoxy)phenyl]ketone (BAPK), bis[4-(3-aminophenoxy)]biphenyl, bis[4-(4-aminophenoxy)]biphenyl, 2,2-bis(4-aminophenoxyphenyl)propane (BAPP), 4,4'-diaminodiphenyl ether, and the like. Among these, 1,3-bis(3-aminophenoxy)benzene (APB) and 1,3-bis(4-aminophenoxy)benzene (TPE-R) are preferred.

However, other acid anhydride residues may be contained as long as the object of the present invention is not impaired. When other acid anhydride residues are included, it is 50 mol% or less, preferably less than 30 mol%, more preferably less than 10 mol% of the total acid anhydride residues.

Other acid anhydride residues include, for example, pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid Acid dianhydride, 2,3,3',4'-benzophenonetetracarboxylic dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, naphthalene-1,2,4,5- Tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, naphthalene-1,2,6,7-tetracarboxylic dianhydride, 4,8-dimethyl-1,2 ,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene- 2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5, 8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 1,4,5,8-tetrachloronaphthalene-2, 3,6,7-tetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3 ,3'',4,4''-p-terphenyltetracarboxylic dianhydride, 2,2'',3,3''-p-terphenyltetracarboxylic dianhydride, 2,3,3 '',4''-p-terphenyltetracarboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-propane dianhydride, 2,2-bis(3,4-dicarboxy phenyl)-propane dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3.4-dicarboxyphenyl)methane dianhydride , bis(2,3-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride anhydride, perylene-4,5,10,11-tetracarboxylic dianhydride, perylene-5,6,11,12-tetracar carboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6,7-tetracarboxylic dianhydride, phenanthrene-1,2,9,10- tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4, 5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, (trifluoromethyl)pyromellitic dianhydride, di (trifluoromethyl)pyromellitic dianhydride, di(heptafluoropropyl)pyromellitic dianhydride, pentafluoroethylpyromellitic dianhydride, bis{3,5-di(trifluoromethyl)phenoxy}pyro Melitic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetra Carboxybiphenyl dianhydride, 2,2',5,5'-tetrakis(trifluoromethyl)-3,3',4,4'-tetracarboxybiphenyl dianhydride, 5,5'-bis(trifluoromethyl) )-3,3',4,4'-tetracarboxydiphenyl ether dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetracarboxybenzophenone dianhydride, bis{ (trifluoromethyl)dicarboxyphenoxy}benzene dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}trifluoromethylbenzene dianhydride, bis(dicarboxyphenoxy)trifluoromethylbenzene dianhydride, bis(di Carboxyphenoxy)bis(trifluoromethyl)benzene dianhydride, bis(dicarboxyphenoxy)tetrakis(trifluoromethyl)benzene dianhydride, 2,2-bis{(4-(3,4-dicarboxyphenoxy)phenyl }hexafluoropropane dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}biphenyl dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}bis(trifluoromethyl)biphenyl dianhydride, bis{(tri fluoromethyl)dicarboxyphenoxy}diphenyl ether dianhydride, bis(dicarboxyphenoxy)bis(trifluoromethyl)biphenyl dianhydride, 1,2, acid anhydride residues derived from 3,4-cyclobutanetetracarboxylic dianhydride, fluorenylidenebisphthalic anhydride, and 1,2,4,5-cyclohexanetetracarboxylic dianhydride; Among these, it is possible to give strength and flexibility to the polyimide film, and the coefficient of thermal expansion (CTE) of the polyimide film does not increase too much and can be controlled within an appropriate range, so pyromellitic dianhydride or 3,3 Anhydride residues derived from ',4,4'-biphenyltetracarboxylic dianhydride are preferred.

Similarly, diamine residues derived from other diamine compounds may be contained as long as they do not interfere with the object of the present invention. When other diamine residues are included, it is 50 mol % or less, preferably less than 30 mol %, more preferably less than 10 mol % of the total diamine residues.

Other diamine residues include, for example, 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (TFMB), bis[4-(aminophenoxy)phenyl]sulfone (BAPS), 4, 6-dimethyl-m-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 2,4-diaminomesitylene, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,5,3',5 '-Tetramethyl-4,4'-diaminodiphenylmethane, 2,4-toluenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4, 4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 2,2-bis(4-aminophenoxyphenyl)propane, 2,2- bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4- aminophenoxy)benzene, benzidine, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 4,4"-diamino-p-terphenyl, 3,3"-diamino-p-terphenyl, bis(p-aminocyclohexyl)methane, bis(p-β-amino-t-butylphenyl)ether, bis(p-β-methyl-δ-aminopentyl)benzene , p-bis(2-methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4 -Bis(β-amino-t-butyl)toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediene Amine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine , 4-(1H,1H,11H-eicosafluoroundecanoxy)-1,3-diaminobenzene, 4-(1H,1H-perfluoro-1-butanoxy)-1,3-diaminobenzene, 4-( 1H,1H-perfluoro-1-heptanoxy)-1,3-diaminobenzene, 4-(1H,1H-perfluoro-1-octanoxy)-1,3-diaminobenzene, 4-pentafluorophenoxy-1,3 -diaminobenzene, 4-(2,3,5,6-tetrafluorophenoxy)-1,3-diaminobenzene, 4-(4-fluorophenoxy)-1,3-diaminobenzene, 4-(1H,1H, 2H,2H-perfluoro-1-hexanoxy)-1,3-diaminobenzene, 4-(1H,1H,2H,2H-perfluoro-1-dodecanoxy)-1,3-diaminobenzene, (2,5) -diaminobenzotrifluoride, diaminotetra(trifluoromethyl)benzene, diamino(pentafluoroethyl)benzene, 2,5-diamino(perfluorohexyl)benzene, 2,5-diamino(perfluorobutyl)benzene, 2,2 '-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, octafluorobenzidine, 4,4'-diaminodiphenyl ether, 2 ,2-bis(4-aminophenyl)hexafluoropropane, 1,3-bis(anilino)hexafluoropropane, 1,4-bis(anilino)octafluorobutane, 1,5-bis(anilino)decafluoropentane, 1,7-bis(anilino)tetradecafluoroheptane, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 3,3'-bis(trifluoromethyl)-4,4'- diaminodiphenyl ether, 3,3',5,5'-tetrakis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 3,3'-bis(trifluoromethyl)-4,4'-diaminobenzophenone, 4, 4'-diamino-p-terphenyl, 1,4-bis(p-aminophenyl)benzene, p-(4-amino-2-trifluoromethylphenoxy)benzene, bis(aminophenoxy)bis(trifluoromethyl) Benzene, bis(aminophenoxy)tetrakis(trifluoromethyl)benzene, 2,2-bis{4-(4-aminophenoxy)phenyl phenyl}hexafluoropropane, 2,2-bis{4-(3-aminophenoxy)phenyl}hexafluoropropane, 2,2-bis{4-(2-aminophenoxy)phenyl}hexafluoropropane, 2,2- bis{4-(4-aminophenoxy)-3,5-dimethylphenyl}hexafluoropropane, 2,2-bis{4-(4-aminophenoxy)-3.5-ditrifluoromethylphenyl}hexafluoropropane, 4, 4'-bis(4-amino-2-trifluoromethylphenoxy)biphenyl, 4,4'-bis(4-amino-3-trifluoromethylphenoxy)biphenyl, 4,4'-bis(4-amino-2 -trifluoromethylphenoxy)diphenylsulfone, 4,4'-bis(3-amino-5-trifluoromethylphenoxy)diphenylsulfone, 2,2-bis{4-(4-amino-3-trifluoromethylphenoxy) phenyl}hexafluoropropane, bis{(trifluoromethyl)aminophenoxy}biphenyl, bis[{(trifluoromethyl)aminophenoxy}phenyl]hexafluoropropane, bis{2-[(aminophenoxy)phenyl]hexafluoroisopropyl} Examples include diamine residues derived from benzene and 4,4'-bis(4-aminophenoxy)octafluorobiphenyl. Among these, from the viewpoint of producing a polyimide with high transparency and a low degree of coloring, 2,2-bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane, 9,9-bis[4- (3-aminophenoxy)phenyl]fluorene, 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl, 4,4′-b bis(2-(trifluoromethyl)-4-aminophenoxy )biphenyl, 2,2-bis(4-(2-(trifluoromethyl)-4-aminophenoxy)phenyl)hexafluoropropane, 4,4′-bis(3-(trifluoromethyl)-4-aminophenoxy ) biphenyl, 4,4′-bis(3-(trifluoromethyl)-4-aminophenoxy)biphenyl, p-bis(2-trifluoromethyl)-4-aminophenoxy]benzene and other diamine compounds Diamine residues are preferred.

In the polyimide of the present embodiment, toughness, thermal expansion, properties, adhesiveness, glass transition temperature (Tg), etc. can be controlled.

Since the resin film of the present invention has a total light transmittance of 80% or more, the main polyimide layer (hereinafter sometimes referred to as "polyimide layer (A)") is composed of polyimide (hereinafter, "main polyimide" ) contains a diamine residue derived from an aromatic diamine compound containing a fluorine atom and/or an acid anhydride residue derived from an aromatic tetracarboxylic acid anhydride containing a fluorine atom. preferable. Here, "main" means having the largest thickness among the plurality of polyimide layers constituting the resin film, preferably 50% or more, more preferably 60% or more of the total thickness of the resin film. It means having a thickness of

The main polyimide constituting the polyimide layer (A) preferably contains a fluorine-containing diamine residue. Since the fluorine-containing diamine residue has a group containing a bulky fluorine atom, interaction such as π-π stacking between polymer chains is reduced, and the aromatic tetracarboxylic acid residue and the aromatic diamine residue are It is thought that the polyimide can be made nearly colorless and transparent because charge transfer (CT) between is less likely to occur.

Fluorine-containing diamine residues include, for example, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB), 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene , 3,4-diamino-2,2′-bis(trifluoromethyl)biphenyl, 4,4′-bis(2-(trifluoromethyl)-4-aminophenoxy)biphenyl, 2,2-bis(4- (2-(trifluoromethyl)-4-aminophenoxy)phenyl)hexafluoropropane, 4,4'-bis(3-(trifluoromethyl)-4-aminophenoxy)biphenyl, 4,4'-bis(3 -(trifluoromethyl)-4-aminophenoxy)biphenyl, p-bis(2-trifluoromethyl)-4-aminophenoxy]benzene, 2,2-bis-[4-(3-aminophenoxy)phenyl]hexa Examples thereof include diamine residues derived from diamine compounds such as fluoropropane.

Among fluorine-containing diamine residues, it is more preferable to contain a diamine residue derived from a diamine compound represented by the following general formula (A1) (hereinafter sometimes referred to as "A1 residue").

In general formula (A1), substituent X independently represents an alkyl group having 1 to 3 carbon atoms substituted with a fluorine atom, and m and n independently represent an integer of 1 to 4.

The A1 residue is an aromatic diamine residue and has a biphenyl skeleton in which two benzene rings are connected by a single bond, so it is easy to form an ordered structure, and the in-plane orientation of the molecular chain is Therefore, it is possible to suppress an increase in the CTE of the polyimide layer (A), which is the main layer, and improve the dimensional stability. From such a viewpoint, the main polyimide constituting the polyimide layer (A) preferably contains 50 mol parts or more of A1 residues with respect to a total of 100 mol parts of all diamine residues, and 50 mol parts or more and 100 It is more preferable to contain within the range of mol parts or less.

Preferred specific examples of A1 residues are 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB), 3,4-diamino-2,2'-bis(trifluoromethyl) Examples include diamine residues derived from diamine compounds such as biphenyl.

The main polyimide constituting the polyimide layer (A) may contain, as a diamine residue other than those described above, a diamine residue derived from a diamine component generally used in polyimide synthesis.

The main polyimide constituting the polyimide layer (A) preferably contains a fluorine-containing acid anhydride residue. Since the fluorine-containing acid anhydride residue has a group containing a bulky fluorine atom, it reduces interactions such as π-π stacking between polymer chains, resulting in an aromatic tetracarboxylic acid residue and an aromatic diamine residue. It is believed that the polyimide can be made nearly colorless and transparent because charge transfer (CT) between it and the group is less likely to occur.

Examples of fluorine-containing acid anhydride residues include acid anhydride residues derived from acid anhydride components such as 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). can be mentioned.

In addition, the main polyimide constituting the polyimide layer (A) is pyromellitic dianhydride ( It preferably contains a tetravalent acid anhydride residue (hereinafter sometimes referred to as "PMDA residue") derived from PMDA). The PMDA residue is preferably contained in an amount of 50 mol parts or more, more preferably 60 mol parts or more and 100 mol parts or less, based on a total of 100 mol parts of all acid anhydride residues. If the PMDA residue is less than 50 mol parts, the CTE of the polyimide layer (A) is high and the dimensional stability is lowered.

In addition, the main polyimide constituting the polyimide layer (A) contains, as an acid anhydride residue other than the above, an acid anhydride residue derived from an acid anhydride component generally used in polyimide synthesis. You can An aromatic tetracarboxylic acid residue is preferred as such an acid anhydride residue. It may also contain alicyclic tetracarboxylic acid residues, such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, fluorenylidene bisphthalic anhydride, 1,2,4,5 Acid-negative residues derived from alicyclic tetracarboxylic dianhydrides such as -cyclohexanetetracarboxylic dianhydride and cyclotanonebisspironorbornanetetracarboxylic dianhydride are preferred.

Next, a method for synthesizing polyimide constituting a plurality of polyimide layers will be described.
The polyimide of the present embodiment can be produced by reacting the above acid anhydride and diamine in a solvent to produce a polyamic acid, followed by heat ring closure. For example, an acid anhydride component and a diamine component are dissolved in approximately equimolar amounts in an organic solvent and stirred at a temperature within the range of 0° C. or higher and 100° C. or lower for 30 minutes to 24 hours for a polymerization reaction to form a polyimide precursor. A polyamic acid is obtained. In the reaction, the reaction components are dissolved in the organic solvent so that the resulting precursor is within the range of 5% by weight to 30% by weight, preferably within the range of 10% by weight to 20% by weight. Organic solvents used in the polymerization reaction include, for example, N,N-dimethylformamide, N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone, 2-butanone, dimethylsulfoxide, dimethyl sulfate, cyclohexanone, dioxane. , tetrahydrofuran, diglyme, triglyme, γ-butyrolacto and the like. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can also be used in combination. The amount of the organic solvent to be used is not particularly limited, but is such that the concentration of the polyamic acid solution (polyimide precursor solution) obtained by the polymerization reaction is about 5% by weight to 30% by weight. It is preferable to adjust the amount used.

In the synthesis of polyimide, each of the above acid anhydrides and diamines may be used alone or in combination of two or more thereof. Thermal expansibility, adhesion, glass transition temperature, etc. can be controlled by selecting the types of acid anhydrides and diamines, and the respective molar ratios when two or more acid anhydrides or diamines are used. .

Moreover, a terminal blocker may be used for the polyimide of the present embodiment. Monoamines or dicarboxylic acids are preferable as the terminal blocking agent. The amount of the terminal blocker to be introduced is preferably in the range of 0.0001 mol or more and 0.1 mol or less, particularly 0.001 mol or more and 0.05 mol or less per 1 mol of the acid anhydride component. Within the range is preferred. Monoamine terminal blockers include, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, aniline, 4-methylaniline and the like are recommended. Among these, benzylamine and aniline are preferably used. Dicarboxylic acids are preferable as the dicarboxylic acid end blocking agent, and a part of them may be ring-closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid and the like are recommended. Among these, phthalic acid and phthalic anhydride can be preferably used.

It is usually advantageous to use the synthesized polyamic acid as a reaction solvent solution, but if necessary, it can be concentrated, diluted, or replaced with another organic solvent. Polyamic acid is also advantageously used because it is generally excellent in solvent solubility. The method for imidating the polyamic acid is not particularly limited, for example, a heat treatment such as heating for 1 hour to 24 hours under a temperature condition within the range of 80 ° C. or higher and 400 ° C. or lower in the solvent is preferably adopted. .

The weight average molecular weight of the polyamic acid is, for example, preferably in the range of 10,000 to 400,000, more preferably in the range of 50,000 to 350,000. If the weight-average molecular weight is less than 10,000, the strength of the film is lowered and the film tends to become brittle. On the other hand, if the weight-average molecular weight exceeds 400,000, the viscosity increases excessively, and defects such as uneven film thickness and streaks tend to occur during coating.

The resin film of the present embodiment has a plurality of polyimide layers, at least one polyimide layer is composed of the polyimide of the present embodiment, may be a film (sheet) made of an insulating resin, or may be a copper foil. , a glass plate, a polyimide-based film, a polyamide-based film, a polyester-based film, or other resin sheet or the like, or an insulating resin film laminated on a base material.

The method for forming the resin film of the present embodiment is not particularly limited, but for example, [1] a method of applying a polyamic acid solution to a supporting substrate, drying it, and then imidating it to produce a resin film (hereinafter referred to as cast method), and [2] a method in which a polyamic acid solution is applied to a supporting substrate and dried, then the polyamic acid gel film is peeled off from the supporting substrate and imidized to produce a resin film. In addition, since the resin film produced in the present embodiment is composed of a plurality of polyimide layers, the method for producing the film may include, for example, [3] applying and drying a polyamic acid solution to a supporting substrate. After repeating a plurality of times, a method of imidizing (hereinafter referred to as a sequential coating method), [4] The support substrate is simultaneously coated and dried with a polyamic acid laminate structure by multilayer extrusion, followed by imidization. method (hereinafter referred to as multilayer extrusion method), and the like. The method of applying the polyimide solution (or polyamic acid solution) onto the substrate is not particularly limited, and it can be applied, for example, by a comma, die, knife, lip coater, or the like. When forming a multi-layered polyimide layer, a method of repeating the operation of applying a polyimide solution (or a polyamic acid solution) to a base material and drying the solution is preferred.

The resin film of the present embodiment may optionally contain an inorganic filler in the polyimide layer as long as the object of the present invention is not hindered. Specific examples include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, and calcium fluoride. These can be used singly or in combination of two or more.

The metal-clad laminate of the present invention is described below.
The metal-clad laminate of the present invention has a metal layer on at least one side of the insulating resin layer, that is, on one side or both sides. The insulating resin layer has two or more polyimide resin layers, at least one of which is the polyimide layer (P1) described above.

In the metal-clad laminate of the present embodiment, for example, in an embodiment in which a metal layer (M1) and a metal layer (M2) are laminated on an insulating resin layer composed of a polyimide layer (P1) and a main polyimide layer (P2), , preferably the following configurations 1 to 4 are exemplified. Preferably, the polyimide layer (P1) in contact with at least one surface of the metal layer (M1) or the metal layer (M2) is an adhesive layer in order to enhance the adhesion between the insulating resin layer and the metal layer. Here, the total thickness of the main polyimide layer (P2) is preferably 50% or more of the thickness of the insulating resin layer.

Configuration 1; M1/P1/P2
Configuration 2; M1/P1/P2/P1
Configuration 3; M1/P1/P2/P1/M2
Configuration 4; M1/P1/P2/P1/P2/P1/M2

In the metal-clad laminate of the present embodiment, the insulating resin layer is composed of a single layer or a plurality of polyimide layers, and preferably has a plurality of polyimide layers. By having a plurality of polyimide layers, an insulating resin layer having excellent physical properties such as heat resistance, adhesiveness, flexibility and transparency can be obtained. The plurality of polyimide layers may have a two-layer structure of a polyimide layer (P1) and another polyimide layer, preferably three layers, and the polyimide layer (P1) may be arranged as an outer layer. More preferably, of the three layers, two outer layers excluding the inner layer are both polyimide layers (P1). For example, when forming a plurality of polyimide layers by a casting method, it may be a two-layer structure in which the polyimide layer (P1) and the polyimide layer other than the polyimide layer (P1) are laminated in this order from the cast surface side. A three-layer structure in which a polyimide layer (P1), a polyimide layer other than the polyimide layer (P1), and the polyimide layer (P1) are laminated in this order from the cast surface side may be employed. As used herein, the term "cast surface" refers to the surface facing the support when the polyimide layer is formed. The support may be a metal layer of a metal-clad laminate, or may be a support for forming a gel film or the like. The surface opposite to the cast surface of the polyimide layers is described as a "laminate surface", but unless otherwise specified, the laminate surface may or may not have a metal layer laminated thereon.

The polyimide constituting the polyimide layer (P1) is preferably a thermoplastic polyimide, which improves adhesion as an insulating resin layer and is suitable for use as an adhesive layer with a metal layer. Therefore, the most preferred embodiment is an insulating resin layer in which the polyimide layer (P1) is directly laminated on the metal layer.

A preferred embodiment of the insulating resin layer has a thermoplastic polyimide layer (P1) and a non-thermoplastic polyimide layer composed of a non-thermoplastic polyimide, and at least one of the non-thermoplastic polyimide layers has a thermoplastic It is preferable to have a polyimide layer (P1) to be a polyimide layer. That is, the polyimide layer (P1) is preferably provided on one side or both sides of the non-thermoplastic polyimide layer.

Also, the non-thermoplastic polyimide layer constitutes a low thermal expansion polyimide layer, and the thermoplastic polyimide layer constitutes a high thermal expansion polyimide layer. Here, the low thermal expansion polyimide layer preferably has a coefficient of thermal expansion (CTE) in the range of 1 ppm/K or more and 25 ppm/K or less, more preferably 3 ppm/K or more and 25 ppm/K or less. say. Further, the high thermal expansion polyimide layer preferably has a CTE of 35 ppm/K or more, more preferably 35 ppm/K or more and 80 ppm/K or less, still more preferably 35 ppm/K or more and 70 ppm/K or less. layer. The polyimide layer can be made into a polyimide layer having a desired CTE by appropriately changing the combination of raw materials to be used, thickness, and drying/curing conditions.
Here, non-thermoplastic polyimide generally refers to polyimide that does not soften or exhibit adhesiveness when heated. A polyimide having a storage modulus of 1.0×10 ⁹ Pa or more at 350° C. and a storage modulus of 1.0×10 ⁸ Pa or more at 350° C. In addition, thermoplastic polyimide is generally a polyimide whose glass transition temperature (Tg) can be clearly confirmed. In the present invention, the storage modulus at 30 ° C. measured using DMA is 1.0 × 10 ⁹ Pa and a storage modulus at 350° C. of less than 1.0×10 ⁸ Pa.

The thickness of the insulating resin layer is within the range of 5 μm or more and 20 μm or less. By controlling the content within such a range, high transparency and colorlessness can be improved. Further, if the thickness of the insulating resin layer is less than the above lower limit, problems may occur such as the inability to ensure electrical insulation and the deterioration of handling properties, making it difficult to handle in the manufacturing process. On the other hand, if the thickness of the insulating resin layer exceeds the above upper limit value, the dimensional change before and after etching becomes large, and yellow to yellowish brown coloring becomes strong, and the visibility of the insulating resin layer decreases. The thickness of the insulating resin layer is preferably in the range of 5 μm or more and 12 μm or less.

In order to maintain the dimensional stability of the metal-clad laminate of the present embodiment and the high transparency and colorlessness of the insulating resin layer, and to improve the adhesion with the metal layer, the polyimide layer (P1) in contact with the metal layer When the thickness is T1 and the thickness of the main polyimide layer (hereinafter sometimes referred to as "polyimide layer (A)") is T2, the thickness of T1 is preferably in the range of 1 μm or more and 4 μm or less, and the thickness of T2 is A range of 4 μm or more and 19 μm or less is preferable. From another point of view, the thickness of T1 is preferably 20% or less of the thickness of the insulating resin layer. Here, “main” means having the largest thickness among the polyimide layers constituting the insulating resin layer, preferably 60% or more, more preferably 70% of the thickness of the insulating resin layer. It means having a thickness equal to or greater than
The main polyimide layer is preferably composed of non-thermoplastic polyimide.

From the viewpoint of heat resistance, the insulating resin layer has a glass transition temperature (Tg) of 280° C. or higher. It is preferably 350° C. or higher, more preferably 380° C. or higher. Moreover, the thermal decomposition temperature (1% weight loss temperature, Td1) is preferably 350° C. or higher, more preferably 450° C. or higher.

The coefficient of thermal expansion (CTE) of the insulating resin layer is within the range of 10 ppm/K or more and 30 ppm/K or less. By controlling the thickness within such a range, deformation such as curling can be suppressed, and high dimensional stability can be ensured. Here, CTE is the average value of thermal expansion coefficients in the MD direction and the TD direction of the insulating resin layer.

From the viewpoint of transparency, the insulating resin layer has a total light transmittance of 80% or more in the visible region. Also, the light transmittance at a wavelength of 450 nm is preferably 70% or more, more preferably 80% or more. For example, it is preferable that the thickness of the insulating resin layer is 20 μm. More preferably, the total light transmittance is 85% or more. By controlling the thickness within such a range, white turbidity due to reflection and scattering of light in the insulating resin layer is suppressed, and excellent transparency is obtained. If the total light transmittance is less than 80%, the turbidity increases and the transparency of the insulating resin layer decreases.

The YI of the insulating resin layer is 10 or less, preferably 5 or less, more preferably 3.5 or less. For example, it is preferable that the thickness of the insulating resin layer is 20 μm. By controlling the thickness within such a range, the insulating resin layer can be made nearly colorless. On the other hand, when the YI is outside the above range, yellow to yellowish brown coloring becomes strong, and the visibility of the insulating resin layer is lowered.

The HAZE of the insulating resin layer is 3% or less, preferably 2% or less. By controlling the thickness within such a range, the visibility of the insulating resin layer can be improved. If the HAZE exceeds 3%, for example, light scattering tends to occur. In addition, HAZE depends on the surface profile of the insulating resin layer, and even if it is a low-profile insulating resin layer, it can achieve both adhesive strength and transparency, and can be suitably used for circuit boards on which fine metal layers are laminated, for example. .

The insulating resin layer has a tensile strength of 100 MPa or more, preferably 150 MPa or more, and more preferably 200 MPa or more. By controlling the thickness within such a range, the strength of the insulating resin layer can be improved. If the tensile strength is less than 100 MPa, the insulating resin layer is likely to tear or break.

The method for forming the insulating resin layer in the metal-clad laminate of the present embodiment is not particularly limited. Production method (hereinafter referred to as casting method) [2] A method of applying a polyamic acid solution to a supporting substrate and drying it, then peeling off the polyamic acid gel film from the supporting substrate and imidizing it to produce a resin film etc. Further, when the insulating resin layer is composed of a plurality of polyimide layers, as an embodiment of the manufacturing method, for example, [3] After repeating coating and drying the polyamic acid solution on the supporting substrate a plurality of times, A method of imidization (hereinafter referred to as a sequential coating method), [4] A method of simultaneously applying and drying a polyamic acid laminate structure to a support substrate by multilayer extrusion and then imidizing (hereinafter referred to as a multilayer extrusion method ) and the like. The method of applying the polyimide solution (or polyamic acid solution) onto the substrate is not particularly limited, and it can be applied, for example, by a comma, die, knife, lip coater, or the like. When forming a multi-layered polyimide layer, a method of repeating the operation of applying a polyimide solution (or a polyamic acid solution) to a base material and drying the solution is preferred.
In particular, it is desirable to include a step of superimposing the surface of the polyimide layer (P1) and the metal layer on the resin film and bonding them by thermocompression.

The polyimide layer of the present embodiment may optionally contain an inorganic filler as long as the object of the present invention is not hindered. Specific examples include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, and calcium fluoride. These can be used singly or in combination of two or more.

The material of the metal layer in the metal-clad laminate of the present embodiment is not particularly limited, but examples include copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, and zirconium. , tantalum, titanium, lead, magnesium, manganese and alloys thereof. Among these, metal elements such as copper, iron, and nickel are preferable. These metal layers are selected so as to exhibit the characteristics required for the purpose of use, such as the light transmittance of the polyimide layer and the adhesiveness with the polyimide layer.

Although the thickness of the metal layer is not particularly limited, it is preferably 100 μm or less, more preferably 1 μm or more and 20 μm or less.

For the metal-clad laminate of the present embodiment, for example, a resin film containing the polyimide of the present embodiment is prepared, a metal is sputtered onto the resin film to form a seed layer, and then a metal layer is formed by, for example, plating. may be prepared by forming.

Alternatively, the metal-clad laminate of the present embodiment may be prepared by preparing a resin film containing the polyimide of the present embodiment and laminating a metal foil thereon by a method such as thermocompression bonding. good.

In the metal-clad laminate of the present embodiment, the surface of the resin film may be subjected to modification treatment such as plasma treatment in order to increase the adhesiveness between the resin film and the metal layer.

Furthermore, the metal-clad laminate of the present embodiment is obtained by casting the coating liquid containing the polyamic acid of the present embodiment on the metal layer, drying it to form a coating film, and then heat-treating it to imidize the polyimide. It may be prepared by a method of forming a layer (casting method). The coating liquid containing polyamic acid of the present embodiment may be cast directly on the metal layer, or may be cast after forming a coating film containing other polyamic acid.

In the casting method, since the polyamic acid resin layer is imidized while being fixed to the metal foil, the expansion and contraction change of the polyimide layer during the imidization process is suppressed, and the anisotropy in the MD and TD directions is reduced. This is the preferred embodiment.

In the case of producing a metal-clad laminate having metal layers on both sides, for example, the transparency of the insulating resin layer may be applied directly onto the polyimide layer of the single-sided metal-clad laminate obtained by the above method, or as necessary. It can be obtained by laminating a metal layer by means of thermocompression bonding or the like after forming an adhesive layer that does not interfere. Also, the hot press temperature in the case of thermocompression bonding of the metal layer is not particularly limited, but it is desirable to be higher than the glass transition temperature of the polyimide layer adjacent to the metal layer used. Further, the hot press pressure is desirably in the range of 1 kg/m ² or more and 500 kg/m ² or less, although it depends on the type of press equipment used.

From the viewpoint of the light transmittance of the insulating resin layer in the metal-clad laminate of the present embodiment, the ten-point average roughness Rzjis of the surface of the metal layer is preferably 0.5 μm or less, more preferably 0.01 μm or more. It is preferably in the range of 0.3 μm or less, more preferably in the range of 0.01 μm or more and 0.2 μm or less. In particular, by setting the ten-point average roughness Rzjis of the surface of the metal layer to 0.2 μm or less, the HAZE of the insulating resin layer can be lowered, which is a more preferable embodiment. From the viewpoint of adhesion to the insulating resin layer, the insulating resin layer in contact with the metal layer is preferably a cast surface.

The 180° peel strength between the insulating resin layer and the metal layer in the metal-clad laminate of the present embodiment is preferably 0.5 kN/m or more. In this specification, the total light transmittance, CTE and peel strength were measured under the conditions described in Examples, and unless otherwise specified, the values were measured at room temperature (23° C.).

The metal-clad laminate of the present embodiment is mainly useful as a material for circuit boards such as FPC, and as a member such as a mask used in the process of manufacturing electronic parts. That is, a patterned metal-clad laminate can be obtained by processing the metal layer of the metal-clad laminate of the present embodiment into a pattern by a conventional method. This patterned metal-clad laminate is used, for example, in circuit boards represented by FPC, electronic circuits including active elements such as transistors and diodes, and passive devices such as resistors, capacitors and inductors, as well as pressure, temperature, Sensor elements that sense light and humidity, light emitting elements, liquid crystal displays, electrophoretic displays, image display elements such as self-luminous displays, wireless and wired communication elements, computing elements, memory elements, MEMS elements, solar cells, thin film transistors, etc. It is available as

EXAMPLES The content of the present invention will be specifically described below based on Examples, but the present invention is not limited to the scope of these Examples. In the following examples, unless otherwise specified, various measurements and evaluations are as follows.

[Calculation of light transmittance and YI (yellowness)]
A polyimide film (50 mm×50 mm) was measured for light transmittance and YI using a UV-3600 spectrophotometer manufactured by Shimadzu Corporation.
1) Light transmittance Based on JIS Z 8722, light transmittances (T400, T430 and T450) for light with wavelengths of 400 nm, 430 nm and 450 nm were calculated.
2) YI
Based on JIS Z 8722, it was calculated based on the formula represented by the following formula (1).
YI=100×(1.2879X−1.0592Z)/Y (1)
X, Y and Z: tristimulus values of test piece YI _(T10) of a polyimide film with a thickness of 10 μm was calculated by substituting the YI value calculated by the above formula (1) into the following formula (2).
YI _(T10) = YI/T x 10 (2)
T: thickness of polyimide film (μm)

[Measurement of coefficient of thermal expansion (CTE)]
A polyimide film (3 mm × 15 mm) is heated from 30 ° C. to 280 ° C. at a heating rate of 10 ° C./min while applying a load of 5.0 g with a thermomechanical analysis (TMA) device, and then from 250 ° C. The temperature was lowered to 100° C., and the thermal expansion coefficient was measured from the amount of elongation (linear expansion) of the polyimide film during the temperature drop.

[Measurement of thermal decomposition temperature (Td1)]
A polyimide film weighing 10 to 20 mg under a nitrogen atmosphere is heated from 30 ° C. to 550 ° C. at a constant rate with a thermogravimetric analysis (TG) device TG / DTA6200 manufactured by SEIKO. The weight at 200° C. was taken as zero, and the temperature at which the weight loss rate was 1% was defined as the thermal decomposition temperature (Td1).

[Calculation of total light transmittance (TT) and HAZE (turbidity)]
A polyimide film (50 mm×50 mm) was measured for total light transmittance (TT) and HAZE (turbidity) according to JIS K 7136 using HAZE METER NDH500 manufactured by Nippon Denshoku Industries Co., Ltd.

[Measurement of viscosity]
The viscosity of the polyamic acid solution obtained in Synthesis Example was measured at 25° C. using a cone-plate viscometer with a constant temperature water bath (manufactured by Tokimec).

[Measurement of glass transition temperature (Tg)]
A polyimide film (10 mm × 22.6 mm) was measured for dynamic viscoelasticity when the temperature was raised from 20 ° C. to 500 ° C. at 5 ° C./min with a dynamic thermomechanical analyzer, and the glass transition temperature (Tan δ maximum value : °C).

[Measurement of peel strength]
Using a tension tester, the resin side of a test sample having a circuit with a width of 1 mm obtained from the laminate was fixed to an aluminum plate with double-sided tape, and the copper was peeled off in the 180 ° direction at a speed of 50 mm / min to measure the peel strength. asked for

[Measurement of surface roughness of copper foil]
A sample was cut into a size of about 10 mm square, fixed on a sample table with double-sided tape, irradiated with soft X-rays, and static electricity on the surface of the copper foil was removed, and then the surface roughness was measured. Using a scanning probe microscope (AFM, manufactured by Bruker AXS, trade name: Dimension Icon type SPM), the ten-point average roughness Rz (RzJis) of the copper foil surface was measured under the following measurement conditions. The measurement conditions are as follows.
Measurement mode; Tapping mode Measurement area; 1 μm×1 μm
Scan speed; 1Hz
Probe; RTESP-300 manufactured by Buruker

[Measurement of tensile strength and tensile elongation]
Cut out the polyimide film to 12.7 mm × 150 mm, using a tensile tester (STROGRAPHVE1D manufactured by TOYO SEIKI Co., Ltd.), in accordance with JIS K 7127, at room temperature 50 mm / min, 100 N, the tensile strength and tensile strength of the film Elongation was measured.

[Measurement of Warpage of Laminate]
The evaluation of warpage was performed by the following method. A laminate of a 10 cm × 10 cm metal layer and a polyimide layer is placed on a horizontal plane with the polyimide layer facing up, and the average height of the lift from the plane at the four corners of the laminate is measured, and is 10 mm or less. was "good", and the case of exceeding 10 mm was "improper".

The abbreviations used in the examples and the like indicate the following compounds.
APB: 1,3-bis(3-aminophenoxy)benzene TPE-R: 1,3-bis(4-aminophenoxy)benzene TFMB: 2,2'-bis(trifluoromethyl)-4,4'-diamino Biphenyl BAPS: bis[4-(aminophenoxy)phenyl]sulfone AAPBZI: 5-amino-2-(4-aminophenyl)benzimidazole PMDA: pyromellitic dianhydride 6FDA: 2,2-bis(3,4- dicarboxyphenyl)-hexafluoropropane dianhydride BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride ODPA: 4,4'-oxydiphthalic dianhydride CBDA: 1,2,3, 4-cyclobutanetetracarboxylic dianhydride DMAc: N,N-dimethylacetamide

Synthesis Examples 1-16
In order to synthesize the polyamic acid solutions A to P, the solvent DMAc was added to a 200 ml separable flask under a nitrogen stream so that the solid content concentration was shown in Table 1, and the diamine component shown in Table 1 was added. and the acid anhydride component were dissolved by heating at 45° C. for 2 hours while stirring. Thereafter, the solution was stirred at room temperature for 2 days to carry out a polymerization reaction to prepare viscous solutions A to P of polyamic acid.

Reference example 1
Polyamic acid solution A was evenly coated on glass (E-XG, thickness 0.5 mm) so that the thickness after curing would be 10 μm, and dried by heating at 100° C. to remove the solvent. Next, stepwise heat treatment was carried out from 100° C. to 360° C. to complete imidization, and a polyimide layer a was formed on the glass to prepare a polyimide layer/glass laminate 1a.

A single-layer polyimide film A was prepared by irradiating the glass side with a 308 nm laser and separating the polyimide layer from the glass by laser lift-off (LLO). The measurement results of polyimide film A are as follows.
HAZE; 0.4%, total light transmittance (TT); 89%, light transmittance (T400); 74%, light transmittance (T430); 86%, light transmittance (T450); 88% , YI; 2.1, CTE; 7 ppm / K, thermal decomposition temperature (Td1); 503 ° C., glass transition temperature (Tg); 214 ° C., tensile elongation; 9.9%, tensile strength; 105 MPa

Reference examples 2 to 16
Single-layer polyimide films B to P were prepared in the same manner as in Reference Example 1, except that the polyamic acid solution shown in Table 2 was used. For polyimide films BN, see HAZE, T.; T. , T400, T430, T450, YI, CTE, Td1, Tg, tensile elongation, and tensile strength were determined. These measurement results are shown in Table 2.

Example 1
On copper foil 1 (electrolytic copper foil, manufactured by Fukuda Metal Foil & Powder Co., Ltd., trade name: CF-T9DA-SV-12, thickness: 12 μm, Rzjis: 0.01 μm), a diluted solution of polyamic acid solution D (viscosity ; 3000 cP) was uniformly applied so that the thickness after curing was 1.5 μm, and then dried by heating at 125° C. to remove the solvent. Next, a diluted solution of polyamic acid solution F (viscosity: 20000 cP) was uniformly applied so that the thickness after curing was 17 μm, and then dried by heating at 125 ° C. to remove the solvent. A diluted solution (viscosity: 3000 cP) of the polyamic acid solution D was uniformly applied so that the thickness after curing was 1.5 μm, and then dried by heating at 125° C. to remove the solvent. After forming the polyamic acid layer, a stepwise heat treatment is performed from 125° C. to 360° C. to complete imidization, and an insulating resin layer 1 having a thickness of 20 μm and consisting of polyimide layer D/polyimide layer F/polyimide layer D is formed. Then, a metal-clad laminate 1 was prepared.The peel strength of the metal-clad laminate 1 was 1.2 kN/m.

A polyimide film 1 was prepared by etching away the copper foil with an aqueous solution of ferric chloride. For polyimide film 1, HAZE, T.; T. , T400, T430, T450, YI _(T10) , CTE, Td1 and Tg were determined. These measurement results are shown in Table 3. Here, YI _(T10) indicates the degree of yellowness when the thickness of the polyimide film is converted to 10 μm.

Examples 2-4
In order to prepare metal-clad laminates 2 to 4 in the same manner as in Example 1, insulating resin layers 2 to 4 were formed by changing the type of polyamic acid and the thickness after heat treatment as shown in Table 3, Metal clad laminates 2-45 were prepared.

Polyimide films 2 to 4 were prepared by etching away the copper foils of metal clad laminates 2 to 4 using an aqueous solution of ferric chloride. HAZE of each polyimide film, T. T. , T400, T430, T450, YI _(T10) , CTE, Td1 and Tg are shown in Table 3.

Example 5
A metal-clad laminate 5 was prepared in the same manner as in Example 1, except that polyamic acid L was used instead of polyamic acid solution F in Example 1. The prepared metal laminate 5 was cut into a size of 15 cm × 15 cm, a copper foil 1 cut into a size of 15 cm × 15 cm was superimposed on the insulating resin layer surface of this laminate, and pressed with a press at 340 ° C./30 min. , a double-sided metal-clad laminate 5 was prepared. The copper foil was partially etched to form a circuit pattern with a width of 1 mm copper foil. When the 180° peel strength was measured, the peel strength on the press side was 1.1 kN/m. Also, a transparent polyimide film 5 was prepared by etching the copper foil on both sides. The total light transmittance of the polyimide film 5 was 86%. Table 3 also shows the physical property measurement results.

Example 6
A diluted solution of polyamic acid solution O (viscosity ; 6160 cP) was uniformly applied so that the thickness after curing was 1.5 μm, and then dried by heating at 125° C. to remove the solvent. Next, a diluted solution of polyamic acid solution F (viscosity: 36000 cP) was uniformly applied so that the thickness after curing was 7 μm, and then dried by heating at 125 ° C. to remove the solvent. A diluted solution (viscosity: 3700 cP) of polyamic acid solution D was uniformly applied so that the thickness after curing was 1.5 μm, and then dried by heating at 125° C. to remove the solvent. After forming the polyamic acid layer, a stepwise heat treatment is performed from 125° C. to 360° C. to complete imidization, and an insulating resin layer 6 having a thickness of 10 μm and consisting of polyimide layer O/polyimide layer F/polyimide layer D is formed. Then, a single-sided metal-clad laminate 6 was prepared.The peel strength of the polyamic acid-applied surface of the single-sided metal-clad laminate 6 was 1.2 kN/m.

Furthermore, copper foil 2 (electrolytic copper foil, manufactured by Fukuda Metal Foil & Powder Co., Ltd., trade name: CF-T9DA-SV-12, thickness: 12 μm, Rzjis: 0 .8 μm) and hot-pressed at 230° C. for 30 minutes at a pressure of 68 kg/m 2 to obtain a double-sided metal-clad laminate 6 . The peel strength of the heat-pressed copper foil and the single-sided metal-clad laminate 6 was 1.1 kN/m.
A polyimide film 6 was prepared by removing the copper foil from the obtained double-sided metal-clad laminate 6 by etching using an aqueous solution of ferric chloride. For polyimide film 1, HAZE, T.; T. , T400, T430, T450, YI(T10), CTE, Td1 and Tg were determined. These measurement results are shown in Table 3. Here, YI (T10) indicates the degree of yellowness when the thickness of the polyimide film is converted to 10 μm.

Examples 7-9
In order to prepare double-sided metal clad laminates 7 to 9 in the same manner as in Example 6, insulating resin layers 7 to 9 were formed by changing the type of polyamic acid and the thickness after heat treatment as shown in Table 3. , double-sided metal-clad laminates 7-9 were prepared.
Polyimide films 7-9 were prepared by etching away the copper foils of metal-clad laminates 7-9 using an aqueous ferric chloride solution. HAZE of each polyimide film, T. T. , T400, T430, T450, YI(T10), CTE, Td1 and Tg are shown in Table 3.

Comparative Examples 1-2
In order to prepare the metal-clad laminates C1 and C2 in the same manner as in Example 1, the insulating resin layers C1 and C2 were formed by changing the type of polyamic acid and the thickness after heat treatment as shown in Table 4, Metal-clad laminates C1 and C2 were prepared.
The copper foils of the metal-clad laminates C1 and C2 were removed by etching using an aqueous solution of ferric chloride to prepare polyimide films C1 and C2. HAZE of each polyimide film, T. T. , T400, T430, T450, YI( _T10 ), CTE, Td1 and Tg are shown in Table 4.

Comparative example 3
A dilute solution (viscosity: 20000 cP) of polyamic acid solution G was applied evenly on the copper foil 1 so that the thickness after curing was 20 μm, and then dried by heating at 125° C. to remove the solvent. Thereafter, stepwise heat treatment was performed from 125° C. to 360° C. to complete imidization, forming an insulating resin layer of the polyimide layer G, and preparing a metal-clad laminate C3. The peel strength of the metal-clad laminate C3 was 0.4 kN/m.

Example 10
Polyamic acid solution D on copper foil 3 (electrolytic copper foil, Nippon Denki Co., Ltd., peelable (P) copper foil, thickness: 2 μm (ultrathin copper foil) + 18 μm (carrier copper foil), Rz: 1.1 μm) (viscosity: 3000 cP) was uniformly applied so that the thickness after curing was 1.0 μm, and then dried by heating at 125° C. to remove the solvent. Next, a diluted solution of polyamic acid solution F (viscosity: 20000 cP) was applied uniformly so that the thickness after curing was 10 μm, and then dried by heating at 125 ° C. to remove the solvent. A diluted solution (viscosity: 3000 cP) of polyamic acid solution D was uniformly applied so that the thickness after curing was 1.0 μm, and then dried by heating at 125° C. to remove the solvent. After forming the polyamic acid layer, a stepwise heat treatment is performed from 125° C. to 360° C. to complete imidization, and an insulating resin layer 10 having a thickness of 12 μm and consisting of polyimide layer D/polyimide layer F/polyimide layer D is formed. Then, a metal-clad laminate 10 was prepared.The peel strength of the metal-clad laminate 10 was 1.2 kN/m.

A polyimide film 10 was prepared by etching away the copper foil using an aqueous solution of ferric chloride. For polyimide film 10, see HAZE, T.; T. , T400, T430, T450, YI _(T10) , CTE, Td1, Tg, peel strength, tensile elongation, tensile strength and warp of the laminate were determined.
Table 5 shows these measurement results. Here, YI _(T10) indicates the degree of yellowness when the thickness of the polyimide film is converted to 10 μm. In the case of the peelable copper foil, the copper foil thickness in Table 5 indicates the thickness of the ultra-thin copper foil excluding the carrier copper foil (the same applies to the following examples).

Examples 11-16
In order to prepare the metal-clad laminates 11 to 16 in the same manner as in Example 1, the insulating resin layers 11 to 16 were formed by changing the type of polyamic acid and the thickness after heat treatment as shown in Table 5, Metal clad laminates 11-16 were prepared.

Here, in Examples 12 to 15, copper foil 4 (electrolytic copper foil, manufactured by Fukuda Metal Foil & Powder Co., Ltd., trade name: CF-T9DA-SV-9, thickness: 9 μm, Rz; 0.8 μm) was used.
On the other hand, in Examples 13, 15, and 16, double-sided metal-clad laminates were used instead of single-sided metal-clad laminates. That is, a single-sided metal-clad laminate was cut into 15 cm × 15 cm, and a copper foil of the same type as the copper foil used as the base material was superimposed on the opposite side (laminate surface) of the insulating resin layer, and pressed at 240 ° C./ Pressing was performed for 30 minutes to prepare double-sided metal-clad laminates 13, 15, and 16.

Polyimide films 11 to 16 were prepared by etching away the copper foils of the metal-clad laminates 11 to 16 using an aqueous solution of ferric chloride. HAZE of each polyimide film, T. T. , T400, T430, T450, YI _(T10) , CTE, Td1, Tg, peel strength, tensile elongation, tensile strength and warpage of the laminate are shown in Table 5.

Comparative Examples 4-5
In order to prepare metal-clad laminates C4 and C5 in the same manner as in Example 10, as shown in Table 6, insulating resin layers C4 and C5 were formed by changing the type of polyamic acid and the thickness after heat treatment, Metal-clad laminates C4 and C5 were prepared.
The copper foils of the metal-clad laminates C4 and C5 were removed by etching using an aqueous ferric chloride solution to prepare polyimide films C4 and C5. HAZE of each polyimide film, T. T. , T400, T430, T450, YI, CTE, Td1, Tg, peel strength, tensile elongation, tensile strength, and warpage of the laminate.

Industrial field of application

The resin film and metal-clad laminate of the present invention are suitably used as an insulating material for manufacturing electronic parts such as FPCs, particularly for transparent FPCs that require colorless transparency for mounting semiconductor elements. In addition, the resin film of the present invention can also be applied to display devices such as liquid crystal display devices, organic EL display devices, touch panels, color filters, and electronic paper, and component parts thereof.

Claims (12)

A polyimide resin film having a non-thermoplastic polyimide layer and a thermoplastic polyimide layer provided on one or both sides of the non-thermoplastic polyimide layer ,
conditions a and b below;
a) the thickness is in the range of 5 μm or more and 200 μm or less;
b) having a total light transmittance of 80% or more;
The filling,
The thermoplastic polyimide constituting the thermoplastic polyimide layer (P1) is an acid anhydride residue derived from an aromatic tetracarboxylic acid anhydride represented by the following general formula (1) with respect to all acid anhydride residues. containing 50 mol% or more of a group, and containing 50 mol% or more of a diamine residue derived from an aromatic diamine compound represented by the following general formula (2) with respect to all diamine residues;
The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer (P2) has an acid anhydride residue derived from pyromellitic dianhydride represented by the following formula (B1) with respect to all acid anhydride residues. A polyimide resin film characterized by containing 50 mol% or more and containing 50 mol% or more of a diamine residue derived from a diamine compound represented by the following general formula (A1) with respect to all diamine residues.
However, the thermoplastic polyimide does not contain a structural unit represented by the following formula (X1) and does not contain a pyromellitic dianhydride residue represented by the following formula (B1).

[In formula (1), X represents a divalent group selected from a single bond, —O—, and —C(CF ₃ ) ₂ —. ]

[In the formula (2), R is independently a halogen atom, an alkyl group or an alkoxy group optionally substituted with a halogen atom having 1 to 6 carbon atoms, or a monovalent hydrocarbon group having 1 to 6 carbon atoms, or represents a phenyl group or a phenoxy group which may be substituted with an alkoxy group, and Z is independently -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, represents a divalent group selected from --CO--, --COO--, --SO ₂ --, --NH-- or --NHCO--, where _n1 is an integer of 0-3 and _n2 is an integer of 0-4; provided that when X in formula (1) is a single bond, Z in formula (2) is independently selected from —O—, —S—, —CH ₂ —, —CH(CH ₃ )—, or —NH—; indicates a divalent group that is ]

[In the general formula (A1), the substituent X independently represents an alkyl group having 1 to 3 carbon atoms and is substituted with a fluorine atom, and m and n independently represent an integer of 1 to 4. ]

2. The resin film according to claim 1, wherein the thermoplastic polyimide layer (P1) is positioned as the outermost layer. In addition to the above conditions a and b, the following condition c;
c) a coefficient of thermal expansion (CTE) within the range of 10 ppm/K or more and 30 ppm/K or less;
The resin film according to claim 1, which satisfies: 2. The resin film according to claim 1, wherein the thermoplastic polyimide layer (P1) accounts for 1% or more and less than 50% of the total thickness. In addition to the above conditions a and b, the following condition d;
d) HAZE is 5% or less;
The resin film according to claim 1, which satisfies: In addition to the above conditions a and b, the following condition e;
e) a YI of 10 or less when the thickness is 10 μm;
The resin film according to claim 1, which satisfies: In addition to the above conditions a and b, the following condition f;
f) a YI of 30 or less when the thickness is 50 μm;
The resin film according to claim 1, which satisfies: A metal-clad laminate comprising an insulating resin layer having a plurality of polyimide layers and a metal layer laminated on at least one surface of the insulating resin layer,
A metal-clad laminate, wherein the insulating resin layer comprises the resin film according to claim 1 . 9. The metal-clad laminate according to claim 8 , wherein the polyimide layer in contact with the metal layer of the insulating resin layer is the thermoplastic polyimide layer (P1). 9. The metal-clad laminate according to claim 8 , wherein the metal layer has a thickness in the range of 1 [mu]m to 20 [mu]m. 9. The metal-clad laminate according to claim 8 , wherein the ten-point average roughness Rzjis of the surface of the metal layer in contact with the insulating resin layer is in the range of 0.01 [mu]m to 0.5 [mu]m. 9. The metal-clad laminate according to claim 8 , wherein the 180[deg.] peel strength between the insulating resin layer and the metal layer is 0.5 kN/m or more.