JP2022045273A - Resin composition for substrate, film, laminate for substrate, circuit board, and electronic apparatus - Google Patents

Abstract

To provide a resin composition for a substrate which makes it possible to improve in a well-balanced manner various performances, such as dielectric properties, thermal aging resistance and toughness.SOLUTION: A resin composition for a substrate includes a thermoplastic polyimide resin (A) and a polyetherimide resin (B).SELECTED DRAWING: None

Description

The present invention relates to a resin composition for a substrate, a film obtained by molding the resin composition for a substrate, and a laminate for a substrate, a circuit board, and an electronic device provided with the film.

Polyimide resin is widely used in automobile parts, aircraft parts, electric / electronic parts, etc. because it is excellent in mechanical properties, heat resistance, flame retardancy, chemical resistance, and the like. For example, a flexible copper-clad laminate (hereinafter, also referred to as FCCL) in which a polyimide film is used as a circuit board material and copper foil is laminated, or a flexible printed circuit board (hereinafter, also referred to as FPC) in which a circuit is formed on FCCL are manufactured. , Used in various electronic devices. At present, in order to support high frequencies for next-generation high-speed communication (5G), it is required to reduce the dielectric constant of the substrate material and to reduce the dielectric loss tangent. Further, in addition to dielectric properties, films for substrate circuits are required to have many performances such as low water absorption, adhesion to copper foil, heat resistance, and tabbing resistance (bending resistance).

In general, as a study for using a polyimide film as a material for a circuit board capable of supporting high frequencies, development of a resin layer in which a resin powder having a low dielectric constant and a low dielectric loss tangent such as a fluororesin is mixed can be mentioned. Patent Document 1 discloses a multilayer polyimide film as a substrate material containing micropowder of polytetrafluoroethylene (PTFE) in polyimide.
Further, Patent Document 2 discloses an electromagnetic wave shielding film having an insulating resin layer and a conductive layer containing a metal adjacent to the insulating resin layer, and the insulating resin layer contains a polyimide having a specific structure.

Japanese Patent Publication No. 2014-526399 Japanese Unexamined Patent Publication No. 2020-007464

However, when the fluororesin is blended with the polyimide resin as in Patent Document 1, it is difficult to uniformly disperse the fluororesin in the polyimide resin, and the dielectric properties may vary depending on the location of the film.

On the other hand, the crystalline polyimide resin composed of tetracarboxylic acid and aliphatic diamine used in Patent Document 2 is excellent in dielectric properties, water absorption, heat resistance and toughness. However, the aliphatic diamine in the crystalline polyimide has a problem that it is excellent in flexibility and moldability, but is inferior in heat aging resistance. Therefore, when it is used for a substrate, if it is subjected to high temperature treatment in, for example, a soldering process, cracks may occur when it is subsequently bent. Further, since an expensive monomer such as an alicyclic diamine is used, there is also a problem that the unit price of the raw material becomes high.
Therefore, an object of the present invention is to provide a resin composition for a substrate, which can have various performances such as dielectric properties, heat aging resistance, and toughness in a well-balanced manner.

As a result of repeated diligent studies, the present inventor has found that a blend of a polyetherimide resin and a thermoplastic polyimide resin can solve the above-mentioned problems, and has reached the present invention. That is, the present invention provides the following [1] to [18].

（一般式（１）において、Ｙ^１～Ｙ^６は、それぞれ独立に水素原子、アルキル基、又はアルコキシ基を表し、Ａｒ^７～Ａｒ^９は、それぞれ独立に、置換基を有していてもよい炭素原子数６～２４のアリーレン基を表し、Ｘ^１は、直接結合、あるいは、－Ｏ－、－ＳＯ_２－、－Ｓ－、－Ｃ（＝Ｏ）－、又は二価の脂肪族炭化水素基のいずれかを表す。）
［１１］ＪＩＳ Ｃ２５６５：１９９２に準拠し、周波数２８ＧＨｚ、厚み１００μｍの条件にて測定される比誘電率が３．８以下である、上記［１］～［１０］のいずれかに記載の基板用樹脂組成物。
［１２］ＪＩＳ Ｃ２５６５：１９９２に準拠し、周波数２８ＧＨｚ、厚み１００μｍの条件にて測定される誘電正接が０．０１５以下である、上記［１］～［１１］のいずれかに記載の基板用樹脂組成物。
［１３］上記［１］～［１２］のいずれかに記載の基板用樹脂組成物からなるフィルム。
［１４］カバーフィルム及びベースフィルムのいずれである上記［１３］に記載のフィルム。
［１５］ＪＩＳ Ｋ７１２７：１９９９に準拠し、引張速度２００ｍｍ／分の条件にて測定される引張破断伸度が１００％以上である、上記［１３］又は［１４］に記載のフィルム。
［１６］上記［１３］～［１５］のいずれかに記載のフィルムと銅箔とを含む、基板用積層体。
［１７］上記［１６］に記載の基板用積層体に回路を形成させてなる、回路基板。
［１８］上記［１７］に記載の回路基板を備える、電子機器。 [1] A resin composition for a substrate, which comprises a thermoplastic polyimide resin (A) and a polyetherimide resin (B).
[2] The thermoplastic polyimide resin (A) has a repeating unit derived from the tetracarboxylic acid component (a-1) and a repeating unit derived from the aliphatic diamine component (a-2). The resin composition for a substrate according to [1].
[3] The resin composition for a substrate according to the above [2], wherein the aliphatic diamine component (a-2) contains at least one of a linear aliphatic diamine and a branched aliphatic diamine.
[4] The resin composition for a substrate according to the above [2] or [3], wherein the aliphatic diamine component (a-2) contains at least an alicyclic diamine.
[5] Any of the above [2] to [4], wherein the aliphatic diamine component (a-2) contains at least one of a linear aliphatic diamine and a branched aliphatic diamine and an alicyclic diamine. The resin composition for a substrate according to.
[6] The content ratio of at least one of the linear aliphatic diamine and the branched aliphatic diamine and the alicyclic diamine is at least one of the linear aliphatic diamine and the branched aliphatic diamine on a molar basis: fat. The resin composition for a substrate according to the above [5], wherein the cyclic diamine is in the range of 1:99 to 70:30.
[7] The resin composition for a substrate according to any one of the above [4] to [6], wherein the alicyclic diamine is 1,3-bis (aminomethyl) cyclohexane.
[8] The resin composition for a substrate according to any one of [1] to [7] above, wherein the thermoplastic polyimide resin (A) has crystallinity.
[9] The content ratio of the thermoplastic polyimide resin (A) and the polyetherimide resin (B) is 75:25 to 10 in terms of mass ratio of the thermoplastic polyimide resin (A): polyetherimide resin (B). : The resin composition for a substrate according to any one of the above [1] to [8], which is in the range of 90.
[10] The resin composition for a substrate according to any one of the above [1] to [9], wherein the polyetherimide resin (B) has a repeating unit represented by the following general formula (1).

(In the general formula (1), Y ¹ to Y ⁶ independently represent a hydrogen atom, an alkyl group, or an alkoxy group, and Ar ⁷ to Ar ⁹ may independently have a substituent. Representing an arylene group having 6 to 24 carbon atoms, X ¹ is a direct bond, or -O-, -SO _2- , -S-, -C (= O)-, or a divalent aliphatic hydrocarbon. Represents one of the groups.)
[11] For the substrate according to any one of the above [1] to [10], which conforms to JIS C2565: 1992 and has a relative permittivity of 3.8 or less measured under the conditions of a frequency of 28 GHz and a thickness of 100 μm. Resin composition.
[12] The resin for a substrate according to any one of the above [1] to [11], which conforms to JIS C2565: 1992 and has a dielectric loss tangent of 0.015 or less measured under the conditions of a frequency of 28 GHz and a thickness of 100 μm. Composition.
[13] A film comprising the resin composition for a substrate according to any one of the above [1] to [12].
[14] The film according to the above [13], which is either a cover film or a base film.
[15] The film according to JIS K7127: 1999, according to the above [13] or [14], wherein the tensile elongation at break measured at a tensile speed of 200 mm / min is 100% or more.
[16] A laminate for a substrate, which comprises the film according to any one of [13] to [15] above and a copper foil.
[17] A circuit board obtained by forming a circuit on the substrate laminate according to the above [16].
[18] An electronic device comprising the circuit board according to the above [17].

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a resin composition for a substrate which can improve various performances such as dielectric properties, heat aging resistance, and toughness in a well-balanced manner.

It is a schematic cross-sectional view which shows an example of the circuit board which includes the base film and the cover film.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to the embodiments described below. Unless otherwise specified, the notation "A to B" for the numerical values A and B means "A or more and B or less". When a unit is attached only to the numerical value B in such a notation, the unit shall be applied to the numerical value A as well.

The resin composition for a substrate of the present invention contains a thermoplastic polyimide resin (A) and a polyetherimide resin (B). Such a resin composition for a substrate has good dielectric properties, heat aging resistance, toughness, etc. in a well-balanced manner, and has low water absorption, so that it can be suitably used for a substrate.

<Thermoplastic polyimide resin (A)>
The thermoplastic polyimide resin (A) used in the present invention is obtained by polymerizing a tetracarboxylic acid component and a diamine component. The thermoplastic polyimide resin (A) preferably has a repeating unit derived from the tetracarboxylic acid component (a-1) and a repeating unit derived from the aliphatic diamine component (a-2).

The tetracarboxylic acid component (a-1) constituting the thermoplastic polyimide resin (A) is cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, Alicyclic tetracarbonic acid such as cyclohexane-1,2,4,5-tetracarboxylic acid, 3,3', 4,4'-diphenylsulfone tetracarboxylic acid, 3,3', 4,4'-benzophenone tetra Examples thereof include carboxylic acid, biphenyltetracarboxylic acid, naphthalene-1,4,5,8-tetracarboxylic acid, pyromellitic acid and the like. These alkyl esters can be used in the polymerization of the thermoplastic polyimide resin (A).

Among them, it is preferable that the component exceeding 50 mol% of the tetracarboxylic acid component (a-1) is pyromellitic acid. Since the tetracarboxylic dian component (a-1) contains pyromellitic acid as a main component, the resin composition for a substrate of the present invention is excellent in heat resistance, secondary processability and low water absorption. From this point of view, among the tetracarboxylic acid components (a-1), the pyromellitic acid is more preferably 60 mol% or more, further preferably 80 mol% or more, and further preferably 90 mol% or more. It is particularly preferable that all (100 mol%) of the tetracarboxylic acid component (a-1) is pyromellitic acid.

The diamine component constituting the thermoplastic polyimide resin (A) preferably contains an aliphatic diamine (a-2) as a main component. That is, the diamine component having a content of more than 50 mol% is preferably an aliphatic diamine (a-2), more preferably 60 mol% or more, further preferably 80 mol% or more, and 90 mol% or more. It is particularly preferable that the content is mol% or more, and it is particularly preferable that all of the diamine components (100 mol%) are aliphatic diamines (a-2). As a result, the resin composition for a substrate of the present invention can have good heat resistance, low water absorption, moldability, secondary processability and the like. The aliphatic diamine in the present invention also includes an alicyclic diamine.

The aliphatic diamine (a-2) is not particularly limited as long as it is a diamine component having amino groups at both ends of the hydrocarbon group, such as an alicyclic diamine, a linear aliphatic diamine, and a branched aliphatic diamine. Can be mentioned. The aliphatic diamine (a-2) preferably contains an alicyclic diamine when heat resistance, heat aging resistance and the like are important. The alicyclic diamine may have an amino group bonded to both ends of the cyclic hydrocarbon (that is, carbon atoms constituting the ring and not adjacent to each other), or to the carbon atom of the cyclic hydrocarbon and the cyclic hydrocarbon. An amino group may be bonded to the end of the hydrocarbon to be bonded, or an amino group may be bonded to the end of each of the two hydrocarbons bonded to the cyclic hydrocarbon.
Specific examples of the alicyclic diamine include 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 4,4'-diaminodicyclohexylmethane, and 4,4'-methylenebis (2-). Methylcyclohexylamine), isophoronediamine, norbornanediamine, bis (aminomethyl) tricyclodecane and the like. Among these, 1,3-bis (aminomethyl) cyclohexane is preferably used from the viewpoints of heat resistance, heat aging property, moldability, secondary processability and the like.

On the other hand, in the resin composition for a substrate of the present invention, when toughness, formability, and secondary processability are emphasized, as an aliphatic diamine (a-2), a linear aliphatic diamine and a branched aliphatic diamine are used. It is preferable to include at least one of. The linear aliphatic diamine and the branched aliphatic diamine may have amino groups at both ends of the linear hydrocarbon and both ends of the branched hydrocarbon.
The linear aliphatic diamine is not particularly limited as long as it is a diamine component having amine groups at both ends of the alkyl group, but specific examples thereof include ethylenediamine (2 carbon atoms), propylene diamine (3 carbon atoms), and the like. Butanediamine (4 carbons), pentandiamine (5 carbons), hexanediamine (6 carbons), heptanediamine (7 carbons), octanediamine (8 carbons), nonanediamine (9 carbons), decanediamine (9 carbons) 10 carbon atoms), undecane diamine (11 carbon atoms), dodecane diamine (12 carbon atoms), tridecane diamine (13 carbon atoms), tetradecane diamine (14 carbon atoms), pentadecane diamine (15 carbon atoms), hexadecane diamine (charcoal) Prime number 16), heptadecanediamine (17 carbons), octadecanediamine (18 carbons), nonadecandiamine (19 carbons), eikosandiamine (20 carbons), triacanthandiamine (30 carbons), tetracontan Examples thereof include linear aliphatic diamines having about 2 to 50 carbon atoms such as diamine (40 carbon atoms) and pentacontandiamine (50 carbon atoms). Among these, a linear aliphatic diamine having 4 to 20 carbon atoms is preferable, and a linear aliphatic diamine having 5 to 16 carbon atoms is more preferable from the viewpoint of excellent moldability, secondary processability, and low moisture absorption. Preferably, a linear aliphatic diamine having 6 to 12 carbon atoms is more preferable.
Examples of the branched aliphatic diamine include those in which a branched structure having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms is bonded to these linear aliphatic diamines.
As the aliphatic diamine (a-2), it is particularly preferable to include a linear aliphatic diamine from the viewpoint of crystallinity.

The thermoplastic polyimide resin (A) may contain a structural unit derived from a diamine component other than the aliphatic diamine (a-2). Specific examples of other diamine components include 1,4-phenylenediamine, 1,3-phenylenediamine, 2,4-toluenediamine, 4,4'-diaminodiphenyl ether, and 3,4'-diaminodiphenyl ether, 4 , 4'-diaminodiphenylmethane, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, α, α' -Bis (4-aminophenyl) 1,4'-diisopropylbenzene, α, α'-bis (3-aminophenyl) -1,4-diisopropylbenzene, 2,2-bis [4- (4-aminophenoxy) Phenyl] propane, 4,4'-diaminodiphenyl sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,6-diaminonaphthalene, 1 , 5-Diaminonaphthalene, p-xylylene diamine, aromatic diamine components such as m-xylylene diamine, ether diamine components such as polyethylene glycol bis (3-aminopropyl) ether and polypropylene glycol bis (3-aminopropyl) ether. , Siloxane diamines and the like.

The aliphatic diamine (a-2) may contain at least one of a linear aliphatic diamine and a branched aliphatic diamine, or an alicyclic diamine, or both, but the various performances are well-balanced and well-balanced. From this point of view, it is preferable to contain at least one of the linear aliphatic diamine and the branched aliphatic diamine and the alicyclic diamine, and it is more preferable to contain both the linear aliphatic diamine and the alicyclic diamine. When at least one of the linear aliphatic diamine and the branched aliphatic diamine and both the alicyclic diamine are contained, the content ratio thereof is on a molar basis, and at least one of the linear aliphatic diamine and the branched aliphatic diamine. : The aliphatic diamine is preferably in the range of 1:99 to 90:10, more preferably 1:99 to 80:20, and even more preferably 1:99 to 70:30. : 90 to 70:30 is particularly preferable, 20:80 to 70:30 is particularly preferable, and 25:75 to 60:40 is most preferable. As long as the ratio of at least one of the linear aliphatic diamine and the branched aliphatic diamine contained in the aliphatic diamine (a-2) to the alicyclic diamine is within such a range, the resin composition for a substrate of the present invention can be used. It tends to have an excellent balance of heat resistance, heat aging resistance, toughness, moldability, etc.

The thermoplastic polyimide resin (A) is preferably crystalline. For the crystalline thermoplastic polyimide resin (A), a crystal melting peak is observed in the differential scanning calorimetry (DSC) measurement. The specific crystal melting temperature of the thermoplastic polyimide resin (A) is preferably 260 ° C. or higher and 350 ° C. or lower, more preferably 270 ° C. or higher and 345 ° C. or lower, and 280 ° C. or higher and 340 ° C. or lower. Is more preferable. When the crystal melting temperature of the thermoplastic polyimide resin (A) is at least the above lower limit value, the heat resistance of the resin composition for a substrate tends to be sufficient. On the other hand, when the crystal melting temperature is not more than the above upper limit value, for example, when molding using the resin composition for a substrate of the present invention, molding or secondary processing is easy at a relatively low temperature, which is preferable.
The crystal melting temperature can be specifically measured by the method described in Examples, and the same applies hereinafter.

The glass transition temperature of the thermoplastic polyimide resin (A) is preferably 150 ° C. or higher and 300 ° C. or lower, more preferably 160 ° C. or higher and 280 ° C. or lower, and 170 ° C. or higher and 260 ° C. or lower. Further preferably, it is particularly preferably 175 ° C. or higher and 250 ° C. or lower, and particularly preferably 180 ° C. or higher and 240 ° C. or lower. When the glass transition temperature of the thermoplastic polyimide resin (A) is at least the above lower limit value, the heat resistance of the resin composition for a substrate tends to be sufficient. On the other hand, when the glass transition temperature is not more than the above upper limit value, it is preferable because it is easy to mold at a relatively low temperature when molding using the resin composition for a substrate of the present invention. Further, when the obtained molded product such as a film is secondarily processed, it is also preferable for the same reason.
The glass transition temperature can be specifically measured by the method described in Examples, and the same applies hereinafter.

<Polyetherimide resin (B)>
The polyetherimide resin (B) is not particularly limited, and its production method and characteristics are described in, for example, US Pat. No. 3,905,942 and US Pat. No. 3,803,085.

Specifically, the polyetherimide resin (B) used in the present invention preferably has a repeating unit represented by the following general formula (1). It is preferable that the polyetherimide resin (B) has the following repeating unit structure in that various performances can be easily improved.

In the general formula (1), Y ¹ to Y ⁶ independently represent a hydrogen atom, an alkyl group, or an alkoxy group, and Ar ⁷ to Ar ⁹ may independently have a substituent. Representing an arylene group having 6 to 24 carbon atoms, X ¹ is a direct bond, or -O-, -SO _2- , -S-, -C (= O)-, or a divalent aliphatic hydrocarbon. Represents one of the groups.
The polyetherimide resin (B) may have a structure in which the repeating unit represented by the above general formula (1) is repeated, for example, from 10 to 1,000, and the number of repeating units is more preferably 20 to 700. , More preferably 30-500. If the number of repeating units is within the range, the viscosity at the time of melting is not too high and the moldability is excellent, and various performances such as heat resistance and heat aging tend to be well-balanced.

The alkyl group in Y ¹ to Y ⁶ is, for example, an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and further preferably 1 to 2 carbon atoms. Yes, specifically preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, Examples thereof include 1-methylpentyl group, n-hexyl group and isohexyl group. The alkoxy group in Y1 to Y6 has, for example, ¹ to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to ⁶ carbon atoms, and further preferably 1 to 2 carbon atoms. Groups, specifically preferably methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, n-hexyloxy. Group etc. Y ¹ to Y ⁶ may be the same as each other or may be different from each other. It is preferable that Y ¹ to Y ⁶ are hydrogen atoms.
Examples of the arylene group in Ar ⁷ to Ar ⁹ include a phenylene group, a naphthylene group, an anthrasenylene group and the like. Examples of the substituent of the arylene group include an alkyl group, a halogen, an alkoxy group, and a halogen-substituted alkyl group. The alkyl group and the alkoxy group as the substituent are, for example, 1 to 6 carbon atoms, preferably 1 to 2 carbon atoms, and specific examples thereof are as described above. The halogen-substituted alkyl group is a group in which one or more hydrogen atoms of the alkyl group are substituted with halogen. The alkyl group in the halogen-substituted alkyl group is the same as above. Examples of the halogen include a chlorine atom, a bromine atom, a fluorine atom, an iodine atom and the like. Ar ⁷ to Ar ⁹ may be the same as each other or may be different from each other. When Ar ⁷ to Ar ⁹ have a substituent, the number of carbon atoms of the arylene group is preferably 6 to 24.
Ar ⁷ to Ar ⁹ are preferably a phenylene group which may have a substituent, and above all, a phenylene group is preferable.
The divalent aliphatic hydrocarbon group in X1 is preferably a divalent aliphatic hydrocarbon group having ¹ to 6 carbon atoms, and more preferably a divalent saturated aliphatic hydrocarbon group.
The divalent saturated aliphatic hydrocarbon group is represented by _{-CyH 2y-} ( _y is an integer of 1 to 6), and specifically, a methylene group, a dimethylene group, a trimethylene group, a propylene group, and an ethylidene group (-). CH (CH ₃ )-), dimethylmethylene group (-C (CH ₃ ) _2- ) and the like can be mentioned.
As X ¹ , a divalent saturated aliphatic hydrocarbon group is preferable, and a dimethylmethylene group (-C (CH ₃ ) _2- ) is more preferable.

In the above general formula (1), Ar ⁹ may have a 1,4- or 1,3-arylene group having 6 to 24 carbon atoms which may have a substituent, but preferably has a substituent. It may be a 1,4-arylene group having 6 to 24 carbon atoms. Since the bond position with the imide group is at the 1st or 4th position, it is structurally stable and has improved heat aging resistance, and also has excellent low water absorption, heat resistance, and impact resistance such as puncture impact strength. Also tends to be easy to realize. Therefore, the polyetherimide resin (B) is preferably represented by the following general formula (2).

In the general formula (2), Y ¹ to Y ⁶ independently represent a hydrogen atom, an alkyl group, or an alkoxy group, and Ar ⁷ to Ar ⁹ may independently have a substituent. Representing an arylene group having 6 to 24 carbon atoms, X ¹ is a direct bond, or -O-, -SO _2- , -S-, -C (= O)-, or a divalent aliphatic hydrocarbon. Represents one of the groups. In (1,4) Ar ⁹ in the general formula (2), the imide group is bonded to the 1-position and the 4-position of the Ar ⁹ group.

Y ¹ to Y ⁶ and X ¹ in the general formula (2) are as described above.
Examples of the arylene group in Ar ⁹ include a 1,4-phenylene group, a 1,4-naphthylene group and a 1,4-anthrasenylene group. Further, these arylene groups may have a substituent as described above, but the substituent is as described above. Ar ⁹ is preferably a 1,4-phenylene group which may have a substituent, and more preferably a 1,4-phenylene group.
Further, in the general formula (2), Ar ⁷ and Ar ⁸ are as described above, but Ar ⁷ and Ar ⁸ are 1,4-1,4-with 6 to 24 carbon atoms which may have a substituent. It is preferably an arylene group, and examples of the 1,4-arylene group include a 1,4-phenylene group, a 1,4-naphthylene group, and a 1,4-anthrasenylene group. Further, these arylene groups may have a substituent as described above, but the substituent is as described above. Ar ⁷ and Ar ⁸ are more preferably 1,4-phenylene groups which may have a substituent, and even more preferably 1,4-phenylene groups.

Specifically, the polyetherimide resin (B) used in the present invention preferably has a structure represented by the following formula (3). Since the polyetherimide resin (B) has the following structure, the resin composition for a substrate tends to have excellent heat aging resistance, and has excellent impact resistance such as low water absorption, heat resistance, and puncture impact strength. There is a tendency for sex to be easily realized. Further, the moldability and the secondary workability tend to be good.

上記一般式（３）において、ｎ（繰り返し数）は通常１０～１，０００の範囲の整数であり、好ましくは２０～７００であり、より好ましくは３０～５００である。ｎがかかる範囲にあれば、溶融時の粘度が高すぎず成形性に優れ、耐熱性、耐熱老化性などの各種性能のバランスに優れる傾向となる。

In the above general formula (3), n (repetition number) is usually an integer in the range of 10 to 1,000, preferably 20 to 700, and more preferably 30 to 500. When n is in the range, the viscosity at the time of melting is not too high and the moldability is excellent, and the balance of various performances such as heat resistance and heat aging tends to be excellent.

As a specific example of the polyetherimide resin (B) having the above structure, for example, it is commercially available from SABIC Innovative Plastics Co., Ltd. under the trade name "Ultem" series.

The glass transition temperature of the polyetherimide resin (B) is preferably 160 ° C. or higher and 300 ° C. or lower, more preferably 170 ° C. or higher and 290 ° C. or lower, and further preferably 180 ° C. or higher and 280 ° C. or lower. , 190 ° C. or higher and 270 ° C. or lower is particularly preferable, and 200 ° C. or higher and 260 ° C. or lower is particularly preferable. When the glass transition temperature of the polyetherimide resin (B) is at least the above lower limit value, the heat resistance of the resin composition for a substrate tends to be sufficient. On the other hand, when the glass transition temperature of the polyetherimide resin (B) is equal to or lower than the above upper limit value, molding or secondary processing can be performed at a relatively low temperature. Therefore, when blended with the thermoplastic polyimide resin (A), it is thermoplastic. Decomposition and deterioration of the polyimide resin (A) are less likely to occur.

In the resin composition for a substrate of the present invention, the content ratio of the thermoplastic polyimide resin (A) and the polyetherimide resin (B) is such that the thermoplastic polyimide resin (A): the polyetherimide resin (B) has a mass ratio. It is preferably in the range of 75:25 to 10:90. Within the above range, various performances such as dielectric properties, heat aging resistance, toughness, and low water absorption can be easily improved in a well-balanced manner. From these viewpoints, the thermoplastic polyimide resin (A): polyetherimide resin (B) is more preferably 70:30 to 20:80, further preferably 65:35 to 30:70, and 65:35 to 65. 35:65 is particularly preferable, and 60:40 to 40:60 is particularly preferable.

Further, the resin composition for a substrate of the present invention has other resins and fillers, various additives, for example, a heat stabilizer, an ultraviolet absorber, and light, in addition to the above-mentioned components, within the range not exceeding the gist of the present invention. Stabilizers, nucleating agents, colorants, lubricants, flame retardants and the like may be appropriately added.
The content of the other resins is not particularly limited, but may be, for example, about 50 parts by mass or less with respect to 100 parts by mass of the total amount of the thermoplastic polyimide resin (A) and the polyetherimide resin (B). The amount may be 30 parts by mass or less, or 10 parts by mass or less, but the resin in the resin composition for a substrate is preferably composed of a thermoplastic polyimide resin (A) and a polyetherimide resin (B). ..

(Dielectric characteristic)
The resin composition for a substrate of the present invention preferably has a low dielectric constant and a low dielectric loss tangent from the viewpoint of reducing transmission loss. Specifically, the relative permittivity of the resin composition for a substrate is preferably 3.8 or less. Further, the dielectric loss tangent of the resin composition for a substrate is preferably 0.015 or less. From the viewpoint of more effectively reducing the transmission loss, the relative permittivity of the resin composition for a substrate is more preferably 3.6 or less, further preferably 3.4 or less, still more preferably 3.2 or less. The dielectric loss tangent of the resin composition for a substrate is more preferably 0.013 or less, further preferably 0.011 or less, further preferably 0.01 or less, and particularly preferably 0.009 or less.
The relative permittivity and the dielectric loss tangent are measured under the conditions of a temperature of 23 ° C. and a frequency of 28 GHz in accordance with JIS C2565: 1992 by preparing a film having a thickness of 100 μm from the resin composition for a substrate and using the film as a test piece. It is a value obtained by.

(Water absorption rate)
The water absorption rate of the resin composition for a substrate is preferably 0.9% or less. By lowering the water absorption rate of the resin composition for a substrate, it becomes easy to prevent the substrate from peeling from the copper foil. In addition, migration resistance is improved and it becomes easier to prevent the occurrence of a short circuit. From the above viewpoint, the water absorption rate of the resin composition for a substrate is more preferably 0.87% or less, further preferably 0.85% or less, and particularly preferably 0.82% or less. The water absorption rate can be measured from the mass change before and after immersion when a film is prepared from the resin composition for a substrate as shown in Examples and the film is immersed in water at 23 ° C. for 24 hours as a test piece.

<Molded body>
Examples of the molded product formed by using the resin composition for a substrate of the present invention include a molded product having a shape such as a film or a plate. Among them, the resin composition for a substrate of the present invention has good balance of various performances such as dielectric properties, heat aging resistance, toughness, and low water absorption, and thus can be suitably used as a film for a substrate.

The film of the present invention may be made of the above-mentioned resin composition for a substrate. The thickness of the film is not particularly limited, but is usually 1 to 300 μm, preferably 10 to 200 μm, more preferably 20 to 180 μm, but it can be suitably used as a film for a substrate. It is particularly preferably from 30 to 150 μm.
Further, it is preferable that the film is formed so that the anisotropy of the physical properties in the flow direction (MD) and the orthogonal direction (TD) thereof is minimized.

Further, since the film of the present invention is used for a substrate, it is often heated to a high temperature in a soldering process or the like. Therefore, from the viewpoint of preventing the film from crystallizing and changing its appearance during its heating, it is preferable that the film is in a crystallized state.
When a crystallized film is used, the relative crystallinity of the film is preferably 60% or more, more preferably 70% or more, further preferably 80% or more, and 85% or more. It is particularly preferable that it is present, and it is particularly preferable that it is 90% or more. The upper limit is usually 100%. When the relative crystallization degree of the film is at least the above lower limit value, it is possible to appropriately prevent a change in appearance due to crystallization during heating.

The relative crystallinity is determined by heating a test piece obtained from a film at a heating rate of 10 ° C./min using a differential scanning calorimeter (Pyris1 DSC, manufactured by PerkinElmer), and melting the crystals obtained at this time. It can be obtained by calculating from the calorific value of the peak (J / g) and the calorific value of the recrystallization peak (J / g) using the following formula (1).
Relative crystallinity (%) = {1- (ΔHc / ΔHm)} × 100 (1)
ΔHc: Calorific value (J / g) of the recrystallization peak of the film material under the heating condition of 10 ° C./min.
ΔHm: Calorific value (J / g) of the crystal melting peak of the film under the heating condition of 10 ° C./min.

If there are a plurality of recrystallization peaks, the total calorific value is ΔHc, and if there are a plurality of crystal melting peaks, the total calorific value is ΔHm. A film in which a recrystallization peak is not observed (ΔHm = 0J / g) when measured with a differential scanning calorimeter is a film, and a film in which a recrystallization peak is observed is a film that is not completely crystallized. can.
In order to keep the relative crystallinity within the above range, for example, the conditions for producing the film may be appropriately adjusted, and the details thereof will be described later.

(Tension breaking elongation)
The film of the present invention complies with JIS K7127: 1999, and it is preferable that the tensile elongation at break measured at a tensile speed of 200 mm / min is 100% or more. When the tensile elongation at break is equal to or higher than the above lower limit, the toughness of the film is improved and the flexibility is improved. In addition, there is a tendency that stable molding or secondary processing is easy without causing troubles such as breakage.
The tensile elongation at break of the film of the present invention is more preferably 105% or more, further preferably 120% or more, still more preferably 130% or more, and most preferably 135% or more. The tensile elongation at break may be high from the viewpoint of toughness, but may be, for example, 300% or less, 250% or less, or 200% or less from the viewpoint of balance with other performance. good.

(Tension modulus)
The tensile elastic modulus of the film of the present invention is preferably 2200 MPa or more and 3200 MPa or less. When the tensile elastic modulus is at least the above lower limit value, the film has sufficient rigidity and tends to have excellent handleability. From this point of view, the tensile elastic modulus is more preferably 2250 MPa or more, and particularly preferably 2300 MPa or more. On the other hand, when the tensile elastic modulus is not more than the above upper limit value, it is preferable because the film has sufficient flexibility. From this point of view, the tensile elastic modulus is more preferably 3100 MPa or less, further preferably 3050 MPa or less, and particularly preferably 3000 MPa or less.

The tensile elongation at break and the tensile elastic modulus can be specifically measured by the methods described in Examples. When the film to be the test piece has directionality, it may be measured in a direction (TD direction) orthogonal to the resin flow direction (extrusion direction in the case of extrusion molding) of the film. When there is no directionality such as press molding, measurement is performed in only one direction, and the measured values are taken as the tensile elongation at break and the tensile elastic modulus.

<Manufacturing method of molded product>
The method for producing the molded body is not particularly limited, but known methods such as extrusion molding, injection molding, blow molding, vacuum molding, pneumatic molding, press molding and the like can be adopted.

Further, the film forming (film forming) method is not particularly limited, but a known method, for example, an extrusion casting method using a T-die, a calendar method, a casting method, or the like can be adopted. Among them, the extrusion casting method using a T-die is preferably used from the viewpoint of film productivity and the like.

Further, the film may be a uniaxial or biaxially stretched film stretched in one direction or two directions, and the stretched film can be produced as a precursor by a T die casting method, a pressing method, a calendar method or the like. Examples thereof include a method of stretching and molding by a roll stretching method, a tenter stretching method and the like after producing the unstretched film of the above, and a method of integrally performing melt extrusion and stretching molding by an inflation method, a tubular method and the like.

The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics, film forming property, etc. of the resin composition for a substrate to be used, but is generally 280 ° C. or higher and 350 ° C. or lower. Generally used single-screw extruders, twin-screw extruders, kneaders, mixers and the like can be used for melt-kneading, and the melt kneading is not particularly limited.

In the case of the extrusion casting method using a T-die, the obtained film may be rapidly cooled and collected in an amorphous state, may be crystallized by heating with a casting roll, or may be collected in an amorphous state. It may be collected in a crystallized state after being heat-treated. Generally, an amorphous film has excellent durability and secondary processability, and a crystallized film has excellent heat resistance and rigidity (stiffness). Therefore, use the optimum crystallized film according to the application and purpose. However, the film of the present invention is preferably a film crystallized as described above.

Further, in order to keep the relative crystallinity within the above range, for example, the conditions for producing the film may be appropriately adjusted, but in the present invention, the following methods (1) to (4) are used. It is preferable to adopt it. These methods may be used in combination. Among them, the method (1), which makes it easy to obtain a uniformly crystallized film and consumes less energy, is preferable.

(1) A method for adjusting cooling conditions when a molten resin composition for a substrate is cooled to form a film shape. The cooling can be performed, for example, by using a cast roll as a cooler and bringing the extruded molten resin into contact with the cast roll. Specifically, it is preferable to adopt the following method.

Examples thereof include a method in which the cooling temperature is set to a temperature 5 to 100 ° C. higher than the glass transition temperature measured by DSC of the crystalline resin. The cooling temperature is more preferably 10 to 80 ° C. higher than the glass transition temperature of the crystalline resin component, and particularly preferably 20 to 60 ° C. higher. By setting the cooling temperature within the above range, the cooling rate of the film can be slowed down, and the relative crystallinity tends to be increased. Specifically, the cooling temperature is preferably 190 ° C. or higher, more preferably 200 ° C. or higher, further preferably 210 ° C. or higher, and particularly preferably 220 ° C. or higher.
On the other hand, the cooling temperature is preferably 300 ° C. or lower, more preferably 280 ° C. or lower, further preferably 260 ° C. or lower, and particularly preferably 250 ° C. or lower.
It is preferable that the temperature of the film is lowered to the above-mentioned cooling temperature by coming into contact with the casting roll. Therefore, the temperature of the casting roll is, for example, 190 to 300 ° C, preferably 200 to 280 ° C, more preferably 210 to 260 ° C, still more preferably 22 to 260 ° C.

(2) A method of reheating a film using a heating roll. Specifically, a method of heating with a roll different from the cast roll such as a longitudinal stretching machine can be mentioned. The temperature at the time of heating is preferably in the same range as the cooling temperature of (1) above.

(3) A method of reheating the film in an oven. Specific examples thereof include a method in which a film is passed through a drying device such as a floating dryer, a tenter, and a band dryer, and heated with hot air. The temperature at the time of heating is preferably in the same range as the cooling temperature of (1) above.

(4) A method of reheating the film with infrared rays. Specifically, a far-infrared heater such as a ceramic heater may be installed between the rolls to heat the film by roll-to-roll, or the film may be passed through a far-infrared dryer to heat the film. The temperature at the time of heating is preferably in the same range as the cooling temperature of (1) above.

The treatments (2) to (4) may be performed at the same time as the film production by providing equipment for that purpose in the film production line, or once the film is wound into a roll, the film roll may be performed. May be carried out by these facilities outside the production line.

<Board>
The resin composition for a substrate of the present invention is used for various substrates, and a molded product such as a film made of the resin composition for a substrate may form at least a part of the substrate. Further, the substrate is typically a circuit board having a circuit. Examples of the circuit board include FPC (Flexible printed circuits) and FCCL (Flexible Cupper Clad Laminate).
In the present invention, as described above, a molded product such as a film has good balance of various performances such as dielectric properties, heat aging resistance, and toughness, and has low water absorption. Therefore, the required characteristics required for the substrate are satisfied, and the substrate is suitably used. In particular, in the present invention, the heat-resistant aging property is improved, so that cracks and the like are less likely to occur when bent even after being heated to a high temperature in a soldering process or the like. Therefore, it is particularly suitable for the above-mentioned FPC, FCCL and the like.

The present invention provides a laminate for a substrate. The laminated body for a substrate is a laminated body including the above-mentioned film of the present invention and a copper foil. The board laminate may form a circuit to form a circuit board. The copper foil may be patterned into a predetermined shape by etching or the like on the circuit board to form wiring or the like. The thickness of the copper foil is, for example, 1 to 80 μm, preferably 3 to 50 μm, and more preferably 5 to 30 μm.

The film of the present invention preferably constitutes either a base film or a cover film. The base film serves as a base material for a circuit board, and it is preferable that a copper foil is provided on the base film. The copper foil is generally attached to the base film via an adhesive layer.
The adhesive layer is not particularly limited, and examples thereof include an epoxy resin adhesive, an acrylic resin adhesive, and a phenol resin adhesive. Among these, an epoxy resin adhesive is preferable.
Further, the copper foil may be surface-treated with a surface treatment agent such as a silane coupling agent, and the copper foil may be bonded to the base film via the surface treatment agent, and the copper foil may be bonded to the surface treatment agent or adhesion. It may be directly bonded to the base film without interposing a layer.

The cover film is sometimes called a coverlay film, and is a film for covering and protecting a copper foil or the like provided on a base film. The cover film is used by being bonded to a surface provided with a copper foil such as a base film or a rigid substrate which is a base material of a circuit board.
The cover film is generally attached to a substrate such as a base film or a rigid substrate via an adhesive layer. The adhesive used for the adhesive layer is as described above. Further, the adhesive layer may be omitted as appropriate, and in that case, the cover film may be adhered to a copper foil surface-treated with a surface treatment agent such as a silane coupling agent, or the adhesive layer or the surface treatment agent may be used. It may be directly adhered to the copper foil without intervention.
Further, the copper foil is generally patterned and partially provided on the base material, but in the portion where the copper foil of the base material is not provided, the cover film may be directly adhered to the base material, or an adhesive layer may be provided. It may be attached to the base material via the substrate.

FIG. 1 shows an example of a circuit board including a base film and a cover film. The configuration of the circuit board using the film of the present invention will be described in more detail with reference to FIG.
As shown in FIG. 1, the circuit board 10 includes a base film 11, a copper foil 12, and a cover film 13. In the circuit board 10, either one of the base film 11 and the cover film 13 may be made of the film of the present invention described above, but both may be made of the film of the present invention.

The copper foil 12 is provided on one surface of the base film 11 and is attached to the base film 11 via the first adhesive layer 14. The copper foil 12 is provided on the entire surface of the base film 11 in FIG. 1, but is generally appropriately patterned by etching or the like.
Further, the cover film 13 may be attached to one surface of the base film 11 provided with the copper foil 12 via the second adhesive layer 15.
However, the first and second adhesive layers 14 and 15 may be omitted as appropriate, the base film 11 and the cover film 13 may be directly adhered to the copper foil 12, and a surface treatment agent such as a silane coupling agent may be used. It may be adhered to the copper foil 12 via.

Further, the cover film 13 may be appropriately provided with holes 16, and the base film 11 may be similarly provided with holes (not shown). Further, in FIG. 1, the copper foil 12 is provided only on one surface of the base film 11, but the copper foil 12 may be provided on both sides of the base film 11. Further, although FIG. 1 shows a configuration in which the base film 11 provided with the copper foil 12 has only one layer, the circuit board may be a multilayer circuit board in which the base film 11 is laminated in multiple layers.

The present invention provides an electronic device having a circuit board. Electronic devices are not particularly limited, but are mobile electronic devices such as mobile phones, smartphones, electronic personal organizers, digital still cameras, video cameras, electronic papers, televisions, DVD players, various audio devices, car navigation devices, instrument panels, etc. In-vehicle display, calculator, printer, scanner, copying machine, refrigerator, washing machine, etc.

Hereinafter, the present invention will be described in more detail with reference to Examples, but these do not limit the present invention in any way. Various measurements of the raw materials described in the present specification, the resin composition for a substrate of the present invention, and the film formed from the resin composition for a substrate were carried out as follows.

(1) Heat-resistant aging property The obtained film was placed in a constant temperature bath at 260 ° C. for 1 hour, and after heat treatment, it was left at room temperature. When the film returned to room temperature was bent to 180 °, the film in which cracks or cracks did not occur was designated as “A”, and the film in which cracks or cracks did not occur was designated as “B”.

(2) Tensile breaking elongation
The obtained film was measured under the conditions of a temperature of 23 ° C. and a test speed of 200 mm / min in accordance with JIS K7127: 1999. The measurement was performed in a direction orthogonal to the resin flow direction of the film (TD direction).

(3) Tension elastic modulus A strip-shaped test piece having a length of 400 mm and a width of 5 mm was prepared from the obtained film, and a "tensile compression tester type 205" (manufactured by Intesco) was used at a temperature of 23 ° C. and a distance between chucks of 300 mm. , The measurement was carried out under the condition of a tensile speed of 5 mm / min. The measurement was performed in a direction orthogonal to the resin flow direction of the film (TD direction).

(4) Relative permittivity
The obtained film was measured under the conditions of a temperature of 23 ° C. and a frequency of 28 GHz according to JIS C2565: 1992.

(5) Dissipation factor
The obtained film was measured under the conditions of a temperature of 23 ° C. and a frequency of 28 GHz according to JIS C2565: 1992.

(6) Water absorption rate A test piece (thickness 100 μm) having a diameter of 10 cm was cut out from the obtained film and obtained as a measurement sample. According to JIS K7209: 2000, the obtained measurement sample was immersed in water for 24 hours at 23 ° C., and the water absorption rate was measured from the mass change before and after immersion.

(7) Glass transition temperature The raw material pellets were kneaded at 340 ° C. using a Φ40 mm isodirectional twin-screw extruder, extruded from a T-die, and then cooled with a casting roll at about 200 ° C. to prepare a film having a thickness of 100 μm. .. For the obtained film, a viscoelastic spectrometer DVA-200 (manufactured by IT Measurement Control Co., Ltd.) was used, and the strain was 0.1%, the frequency was 10 Hz, and the temperature range was 20 to 400 in accordance with JIS K7424-4: 1999. Dynamic viscoelasticity measurement was performed under the conditions of ° C. and a heating rate of 3 ° C./min. The temperature at the peak of the obtained tensile loss coefficient (tan δ) was defined as the glass transition temperature.

(8) Crystal melting temperature The raw material pellets were kneaded at 340 ° C. using a Φ40 mm isodirectional twin-screw extruder, extruded from a T-die, and then cooled with a casting roll at about 200 ° C. to prepare a film having a thickness of 100 μm. .. For the obtained film, in accordance with JIS K7121: 2012, using a differential scanning calorimeter Pyris1 DSC (manufactured by PerkinElmer), the differential scanning calorimeter Pyris1 has a temperature range of 25 to 380 ° C. and a heating rate of 10 ° C./min. Using DSC (manufactured by PerkinElmer), the crystal melting temperature was determined from the peak top temperature of the DSC curve detected in the reheating process.

(9) Relative Crystallinity The relative crystallinity of the obtained film was measured by the method described in the specification.

[Thermoplastic polyimide resin (A)]
(A) -1: Thermoplastic polyimide resin (manufactured by Mitsubishi Gas Chemicals Co., Ltd., trade name: Serprim TO 65S, tetracarboxylic acid component: pyromellitic acid = 100 mol%, diamine component: 1,3-bis (aminomethyl) Cyclohexane / octamethylenediamine = 60/40 mol%, crystal melting temperature (DSC measurement): 322 ° C, glass transition temperature (dynamic viscoelastic measurement): 208 ° C)

[Polyetherimide resin (B)]
(B) -1: Polyetherimide resin (manufactured by SABIC Innovative Plastics, UltemCRS5001, glass transition temperature (dynamic viscoelastic measurement): 240 ° C.)
(B) -2: Polyetherimide resin (manufactured by SABIC Innovative Plastics, Ultem 1010, glass transition temperature (dynamic viscoelastic measurement): 232 ° C.)

(Example 1)
(A) -1 and (B) -1 are dry-blended at a mixing mass ratio of 60:40, kneaded at 340 ° C. using a Φ40 mm isodirectional twin-screw extruder, extruded from a T-die, and then about. The film was cooled with a casting roll at 200 ° C. to prepare a film having a thickness of 100 μm. Using the obtained film, heat aging resistance, tensile elongation at break, relative permittivity, dielectric loss tangent, tensile elastic modulus, and water absorption were evaluated. The relative crystallinity of the film was also measured. The results are shown in Table 1.

(Example 2)
Films were prepared and evaluated in the same manner as in Example 1 except that the mixed mass ratio of (A) -1 and (B) -1 was 40:60. The results are shown in Table 1.

(Example 3)
Films were prepared and evaluated in the same manner as in Example 1 except that the mixed mass ratio of (A) -1 and (B) -1 was set to 20:80. The results are shown in Table 1.

(Comparative Example 1)
Films were prepared and evaluated in the same manner as in Example 1 except that (A) -1 was used alone. The results are shown in Table 1.

(Comparative Example 2)
A film was prepared and evaluated in the same manner as in Example 1 except that (B) -2 was used alone. The results are shown in Table 1.

The resin compositions for substrates of Examples 1 to 3 were excellent in heat aging resistance, toughness (flexibility: tensile elongation at break) and dielectric properties, and also had a low water absorption rate.
On the other hand, the resin composition for a substrate of Comparative Example 1 was inferior in heat aging resistance, and the resin composition for a substrate of Comparative Example 2 had a high water absorption rate, and various performances could not be well-balanced.

10 Circuit board 11 Base film 12 Copper foil 13 Cover film 14 First adhesive layer 15 Second adhesive layer 16 holes

Claims (18)

A resin composition for a substrate, which comprises a thermoplastic polyimide resin (A) and a polyetherimide resin (B). The first aspect of the present invention is that the thermoplastic polyimide resin (A) has a repeating unit derived from the tetracarboxylic acid component (a-1) and a repeating unit derived from the aliphatic diamine component (a-2). The resin composition for a substrate according to the above. The resin composition for a substrate according to claim 2, wherein the aliphatic diamine component (a-2) contains at least one of a linear aliphatic diamine and a branched aliphatic diamine. The resin composition for a substrate according to claim 2 or 3, wherein the aliphatic diamine component (a-2) contains at least an alicyclic diamine. The substrate for a substrate according to any one of claims 2 to 4, wherein the aliphatic diamine component (a-2) contains at least one of a linear aliphatic diamine and a branched aliphatic diamine and an alicyclic diamine. Resin composition. The content ratio of at least one of the linear aliphatic diamine and the branched aliphatic diamine and the alicyclic diamine is at least one of the linear aliphatic diamine and the branched aliphatic diamine on a molar basis: alicyclic diamine. The resin composition for a substrate according to claim 5, which is in the range of 1:99 to 70:30. The resin composition for a substrate according to any one of claims 4 to 6, wherein the alicyclic diamine is 1,3-bis (aminomethyl) cyclohexane. The resin composition for a substrate according to any one of claims 1 to 7, wherein the thermoplastic polyimide resin (A) has crystallinity. The content ratio of the thermoplastic polyimide resin (A) and the polyetherimide resin (B) is 75:25 to 10:90 in terms of mass ratio of the thermoplastic polyimide resin (A): polyetherimide resin (B). The resin composition for a substrate according to any one of claims 1 to 8, which is a range. The resin composition for a substrate according to any one of claims 1 to 9, wherein the polyetherimide resin (B) has a repeating unit represented by the following general formula (1).

(In the general formula (1), Y ¹ to Y ⁶ independently represent a hydrogen atom, an alkyl group, or an alkoxy group, and Ar ⁷ to Ar ⁹ may independently have a substituent. Representing an arylene group having 6 to 24 carbon atoms, X ¹ is a direct bond, or -O-, -SO _2- , -S-, -C (= O)-, or a divalent aliphatic hydrocarbon. Represents one of the groups.) The resin composition for a substrate according to any one of claims 1 to 10, wherein the relative permittivity measured under the conditions of a frequency of 28 GHz and a thickness of 100 μm is 3.8 or less according to JIS C2565: 1992. The resin composition for a substrate according to any one of claims 1 to 11, wherein the dielectric loss tangent measured under the conditions of a frequency of 28 GHz and a thickness of 100 μm is 0.015 or less according to JIS C2565: 1992. A film comprising the resin composition for a substrate according to any one of claims 1 to 12. The film according to claim 13, which is either a cover film or a base film. The film according to claim 13 or 14, according to JIS K7127: 1999, wherein the tensile elongation at break measured at a tensile speed of 200 mm / min is 100% or more. A laminate for a substrate, comprising the film according to any one of claims 13 to 15 and a copper foil. A circuit board obtained by forming a circuit on the substrate laminate according to claim 16. An electronic device comprising the circuit board according to claim 17.

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