JP2023006359A - Resin composition, film, laminate, circuit board, and electronic apparatus - Google Patents

Abstract

To provide a resin composition which enables production of a film having good dielectric characteristics and thermal aging resistance.SOLUTION: A resin composition contains a thermoplastic polyimide resin (A) and a phenolic antioxidant (B).SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a resin composition, a film obtained by molding the resin composition, and a laminate, a circuit board, and an electronic device comprising the film.

Polyimide resins are widely used for automobile members, aircraft members, electrical and electronic members, and the like, due to their excellent mechanical properties, heat resistance, flame resistance, 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, and a flexible printed circuit board (hereinafter also referred to as FPC) in which a circuit is formed on FCCL are manufactured. , are used in various electronic devices.
At present, there is a demand for a low dielectric constant and a low dielectric loss tangent for substrate materials in order to support high frequencies for next-generation high-speed communication (5G). In addition to dielectric properties, films for substrate circuits are required to have many other properties, such as low water absorption, adhesion to copper foil, heat resistance, and tab bending resistance (bending resistance).

As a circuit board material using a polyimide resin, for example, Patent Document 1 discloses a crystalline polyimide resin made of a thermoplastic polyimide resin prepared from at least a tetracarboxylic acid component and a diamine component containing an aliphatic diamine as a main component. Thermoplastic polyimide resin films have been proposed.
Further, Patent Document 2 proposes a polyimide resin composition containing a thermoplastic polyimide resin (A) and a phosphazene compound (B).
Furthermore, Patent Document 3 proposes a highly heat-resistant and highly slidable film in which a fluororesin is added to a crystalline thermoplastic polyimide resin.

JP 2020-177987 A WO2020/004440 JP 2019-112502 A

A crystalline polyimide resin composed of a tetracarboxylic acid and an aliphatic diamine used in Patent Document 1 is excellent in dielectric properties, water absorption, heat resistance, and toughness. However, although the aliphatic diamine and tetracarboxylic acid in the crystalline polyimide can lower the processing temperature of the polyimide and impart thermoplasticity, they are easily decomposed and have poor heat aging resistance. Therefore, when it is used for a substrate, if it is subjected to a high-temperature treatment in a soldering process or the like, cracks or the like may occur when it is subsequently bent. In addition, there is a problem that the thermal decomposition of the polyimide resin deteriorates the dielectric properties of the film, especially the value of the dielectric loss tangent.
In order to improve the above problems, Patent Documents 2 and 3 propose modification of polyimide with an additive, but no detailed study is made on suppression of thermal decomposition.

Accordingly, an object of the present invention is to provide a resin composition capable of improving dielectric properties and heat aging resistance of a film.
In the present invention, the term "heat aging resistance" means that there is no significant deterioration in mechanical properties and dielectric properties after heating the film at 240°C or 260°C.

The present invention provides the following [1] to [21].

[1] A resin composition containing a thermoplastic polyimide resin (A) and a phenolic antioxidant (B).
[2] The above [1], wherein the thermoplastic polyimide resin (A) has repeating units derived from the tetracarboxylic acid component (a-1) and repeating units derived from the aliphatic diamine component (a-2). The resin composition according to .
[3] The resin composition according to [2] above, 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 according to [2] or [3] above, wherein the aliphatic diamine component (a-2) contains at least an alicyclic diamine.
[5] Any one of [2] to [4] above, 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 according to 1.
[6] The content ratio of at least one of a linear aliphatic diamine and a branched aliphatic diamine and an alicyclic diamine is, on a molar basis, at least one of a linear aliphatic diamine and a branched aliphatic diamine: The resin composition according to [5] above, wherein the alicyclic diamine is in the range of 1:99 to 90:10.
[7] The resin composition according to any one of [4] to [6] above, wherein the alicyclic diamine is 1,3-bis(aminomethyl)cyclohexane.
[8] The resin composition according to any one of [1] to [7] above, wherein the thermoplastic polyimide resin (A) has crystallinity.
[9] The content of the phenolic antioxidant (B) is 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the thermoplastic polyimide resin (A) [1] to [ 8], the resin composition according to any one of the above.
[10] The resin composition according to any one of [1] to [9] above, wherein the phenolic antioxidant (B) is a polyfunctional phenolic antioxidant.
[11] Any one of the above [1] to [10], wherein the phenolic antioxidant (B) contains at least one of a hindered phenolic antioxidant and a semi-hindered phenolic antioxidant. of the resin composition.
[12] The resin composition according to any one of [1] to [11] above, wherein the phenolic antioxidant (B) has a weight average molecular weight of 300 or more.
[13] The above [1]-[ 12], the resin composition according to any one of the above.
[14] The resin composition according to any one of [1] to [13] above, which has a viscosity retention rate of 70% or more after being heated at 240° C. for 1 hour.
[15] The resin composition according to any one of [1] to [14] above, which has a viscosity retention rate of 50% or more after being heated at 260° C. for 1 hour.
[16] The resin composition according to any one of [1] to [15] above, which has a dielectric loss tangent of 0.007 or less at a frequency of 10 GHz and a thickness of 200 μm, as measured in accordance with JIS C2565:1992. thing.
[17] A film made of the resin composition according to any one of [1] to [16] above.
[18] The film according to [17] above, which is a cover film or base film for a substrate.
[19] A laminate obtained by laminating the film described in [17] or [18] above and a copper foil.
[20] A circuit board obtained by forming a circuit on the laminate according to [19] above.
[21] An electronic device comprising the circuit board according to [20] above.

According to the resin composition of the present invention, the dielectric properties and heat aging resistance of the film can be improved.

1 is a schematic cross-sectional view showing an example of a circuit board including a base film and a cover film; FIG.

Although the present invention will be described in detail below, the present invention is not limited to the embodiments described below. In addition, unless otherwise specified, the notation "A to B" for numerical values A and B means "A or more and B or less". If a unit is attached only to the numerical value B in such notation, the unit is applied to the numerical value A as well.

The resin composition of the present invention contains a thermoplastic polyimide resin (A) and a phenolic antioxidant (B). Such a resin composition has good dielectric properties and heat aging resistance, and can be suitably used for substrates.

<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 repeating units derived from the tetracarboxylic acid component (a-1) and repeating units derived from the aliphatic diamine component (a-2).

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

Above all, it is preferable that pyromellitic acid accounts for more than 50 mol % of the tetracarboxylic acid component (a-1). By using pyromellitic acid as the main component of the tetracarboxylic acid component (a-1), the resin composition of the present invention is excellent in heat resistance, secondary workability and low water absorption. From this point of view, pyromellitic acid in the tetracarboxylic acid component (a-1) is more preferably 60 mol% or more, still more preferably 80 mol% or more, and preferably 90 mol% or more. It is particularly preferred 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 the aliphatic diamine (a-2) as a main component. That is, it is preferable that more than 50 mol% of the diamine component is the aliphatic diamine (a-2), more preferably 60 mol% or more, further preferably 80 mol% or more, and 90 mol % or more is particularly preferable, and it is particularly preferable that all (100 mol %) of the diamine component is the aliphatic diamine (a-2). As a result, the resin composition of the present invention can be improved in heat resistance, low water absorption, moldability, secondary processability, and the like. Alicyclic diamines are also included in the aliphatic diamines in the present invention.

The aliphatic diamine (a-2) is not particularly limited as long as it is a diamine component having amino groups at both ends of a hydrocarbon group, such as alicyclic diamines, linear aliphatic diamines, branched aliphatic diamines, and the like. is mentioned. The aliphatic diamine (a-2) preferably contains an alicyclic diamine when importance is placed on heat resistance, heat aging resistance, and the like. The alicyclic diamine may have amino groups attached to both ends of the cyclic hydrocarbon (that is, carbon atoms that constitute a ring and are not adjacent to each other), or the carbon atoms of the cyclic hydrocarbon and the cyclic hydrocarbon An amino group may be bonded to the terminal of the hydrocarbon to be bonded, or an amino group may be bonded to the terminal of each of the two hydrocarbons bonded to the cyclic hydrocarbon.
Specific examples of alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4′-diaminodicyclohexylmethane, 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 viewpoint of heat resistance, heat aging resistance, moldability, secondary workability, and the like.

On the other hand, in the resin composition of the present invention, when emphasis is placed on toughness, moldability, and secondary workability, at least a linear aliphatic diamine and a branched aliphatic diamine are used as the aliphatic diamine (a-2). Preferably one is included. Linear aliphatic diamines and branched aliphatic diamines preferably have amino groups at both ends of the linear hydrocarbon and at both ends of the branched hydrocarbon.
The linear aliphatic diamine is not particularly limited as long as it is a diamine component having an amine group at both ends of an alkyl group. Specific examples include ethylenediamine (2 carbon atoms), propylenediamine (3 carbon atoms), butanediamine (4 carbon atoms), pentanediamine (5 carbon atoms), hexanediamine (6 carbon atoms), heptanediamine (7 carbon atoms), octanediamine (8 carbon atoms), nonanediamine (9 carbon atoms), decanediamine ( 10 carbon atoms), undecanediamine (11 carbon atoms), dodecanediamine (12 carbon atoms), tridecanediamine (13 carbon atoms), tetradecanediamine (14 carbon atoms), pentadecanediamine (15 carbon atoms), hexadecanediamine (15 carbon atoms) number 16), heptadecanediamine (17 carbon atoms), octadecanediamine (18 carbon atoms), nonadecanediamine (19 carbon atoms), eicosanediamine (20 carbon atoms), triacontanediamine (30 carbon atoms), tetracontane Linear aliphatic diamines having about 2 to 50 carbon atoms such as diamine (40 carbon atoms) and pentacontanediamine (50 carbon atoms) can be mentioned. Among these, linear aliphatic diamines having 4 to 20 carbon atoms are preferable, and linear aliphatic diamines having 4 to 16 carbon atoms are more preferable from the viewpoint of excellent moldability, secondary workability, and low hygroscopicity. A straight-chain aliphatic diamine having 6 to 12 carbon atoms is preferred, and a straight-chain aliphatic diamine having 8 carbon atoms, for example, can be preferably used.
Branched aliphatic diamines include those obtained by bonding branched structures having preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, to these linear aliphatic diamines.
From the viewpoint of crystallinity, the aliphatic diamine (a-2) particularly preferably contains a linear aliphatic diamine.

The thermoplastic polyimide resin (A) may contain structural units derived from diamine components 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, 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'-diaminodiphenylsulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,6-diaminonaphthalene, 1, aromatic diamine components such as 5-diaminonaphthalene, p-xylylenediamine and m-xylylenediamine; ether diamine components such as polyethylene glycol bis(3-aminopropyl) ether and polypropylene glycol bis(3-aminopropyl) ether; Examples include siloxane diamines.

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. From the point of view, it preferably contains at least one of a linear aliphatic diamine and a branched aliphatic diamine as well as an alicyclic diamine, and more preferably contains both a linear aliphatic diamine and an alicyclic diamine. When both at least one of a linear aliphatic diamine and a branched aliphatic diamine and an alicyclic diamine are included, the content ratio of these is on a molar basis, at least one of the linear aliphatic diamine and the branched aliphatic diamine : The alicyclic diamine is preferably in the range of 1:99 to 90:10, more preferably 1:99 to 80:20, even more preferably 1:99 to 70:30, and 10 : 90 to 70:30, particularly preferably 20:80 to 70:30, most preferably 25:75 to 60:40. As long as the proportion of at least one of the linear aliphatic diamine and the branched aliphatic diamine contained in the aliphatic diamine (a-2) and the alicyclic diamine is within such a range, the resin composition of the present invention is heat resistant. , heat aging resistance, toughness, moldability, etc. are well balanced.

The thermoplastic polyimide resin (A) preferably has crystallinity. The crystalline thermoplastic polyimide resin (A) exhibits a crystalline melting peak in differential scanning calorimeter (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 crystalline melting temperature of the thermoplastic polyimide resin (A) is at least the above lower limit, the resin composition tends to have sufficient heat resistance. On the other hand, if the crystal melting temperature is at most the above upper limit, for example, when molding using the resin composition of the present invention, molding or secondary processing can be easily performed at a relatively low temperature, which is preferable.
The crystalline 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. It is more 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, the resin composition tends to have sufficient heat resistance. On the other hand, if the glass transition temperature is equal to or lower than the above upper limit, the resin composition of the present invention can be easily molded at a relatively low temperature, which is preferable. For the same reason, secondary processing of the molded article such as the obtained film is also preferable.
The glass transition temperature can be specifically measured by the method described in Examples, and the same applies hereinafter.

<Phenolic antioxidant (B)>
The phenolic antioxidant (B) used in the present invention may be a monofunctional phenolic antioxidant having one phenolic hydroxyl group in one molecule, or two or more phenolic hydroxyl groups in one molecule. polyfunctional phenolic antioxidants may be used, but polyfunctional phenolic antioxidants are preferred from the viewpoint of heat aging resistance.

Phenolic antioxidants (B) include hindered phenol antioxidants, semi-hindered phenol antioxidants and less hindered phenol antioxidants. It preferably contains at least one of a hindered phenolic antioxidant and a semi-hindered phenolic antioxidant.
Examples of hindered phenol antioxidants include 2,6-di-t-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol), 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, pentaerythritol tetrakis [3 -(3,5-di-t-butyl-4-hydroxyphenyl)propionate], n-octadecyl-3-(4′-hydroxy-3′,5′-di-t-butylphenyl)propionate, n-octadecyl -2-(4'-hydroxy-3',5'-di-t-butylphenyl) propionate, 1,6-hexanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate, di-n-octadecyl-3,5-di -t-butyl-4-hydroxybenzylphosphonate, N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-dihydrocinnamamide), N,N'-ethylenebis[3- (3,5-di-t-butyl-4-hydroxyphenyl)propionamide], N,N'-tetramethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide] , N,N′-hexamethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide], N,N′-bis[3-(3,5-di-t- butyl-4-hydroxyphenyl)propionyl]hydrazine, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate and the like.
Further, semi-hindered phenol antioxidants include, for example, 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1- dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, triethylene glycol bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate] (alias: Ethylenebis(oxyethylene)bis[3-(3-(5-t-butyl-4-hydroxy-m-tolyl)propionate])), 2-t-butyl-6-methyl-4-{3-[( 2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy]propyl}phenol, 2-t-butyl-6- (3′-t-butyl-5′-methyl-2′-hydroxybenzyl)-4-methylphenyl acrylate, N,N′-ethylenebis[3-(3-t-butyl-5-methyl-4-hydroxy phenyl)propionamide], N,N'-hexamethylenebis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionamide], N,N'-bis[3-(3-t -Butyl-5-methyl-4-hydroxyphenyl)propionyl]hydrazine and the like.
Reshindered phenol antioxidants include, for example, 4,4′-thiobis(3-methyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t -butylphenyl)butane, 4,4′-butylidenebis(3-methyl-6-t-butylphenol), 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanate nurate and the like.
These phenolic antioxidants can be used alone or in combination of two or more.
Among the above, from the viewpoint of further suppressing thermal decomposition of the thermoplastic polyimide resin (A-1), phenol-based antioxidants containing no phosphorus in the molecule are preferred.

From the viewpoint of heat aging resistance, the weight average molecular weight of the phenolic antioxidant (B) is preferably 300 or more, more preferably 400 or more, and even more preferably 500 or more. Although the upper limit of the weight average molecular weight of the phenolic antioxidant (B) is not particularly limited, it may be, for example, 3000 or less, preferably 2000 or less.

The amount of the phenolic antioxidant (B) added in the resin composition of the present invention is 0.01 part by mass with respect to 100 parts by mass of the thermoplastic polyimide resin (A) from the viewpoint of achieving both dielectric properties and heat aging resistance. 5 parts by mass or less is preferable, 0.02 parts by mass or more and 3 parts by mass or less is more preferable, and 0.05 parts by mass or more and 1 part by mass or less is even more preferable.

<Non-phenolic antioxidant (C)>
The resin composition of the present invention preferably further contains a non-phenolic antioxidant (C) in order to further improve heat aging resistance.
The non-phenolic antioxidant (C) is not particularly limited, but is preferably at least one selected from the group consisting of sulfur-based antioxidants, phosphorus-based antioxidants and amine-based antioxidants, from the viewpoint of heat aging resistance. , sulfur-based and/or phosphorus-based antioxidants are more preferred, and sulfur-based antioxidants are even more preferred.
Examples of sulfur-based antioxidants include dilauryl-3,3-thiodipropionate, dimyristyl-3,3-thiodipropionate, distearyl-3,3-thiodipropionate, pentaerythrityl tetrakis (3 -laurylthiopropionate), ditridecyl-3,3-thiodipropionate, 2-mercaptobenzimidazole, and the like.
Examples of phosphorus antioxidants include tris(2,4-t-butylphenyl)phosphite, 3,9-bis(2,6-t-butyl-4-methylphenoxy)-2,4,8, 10-tetraoxa-3,9-diphosphaspiro[5,5 undecane], tetra(C12-C15 alkyl)-4,4'-isopropylidene diphenyl diphosphite, 1,1'-biphenyl-4,4'-diylbis[ bis(2,4-di-t-butylphenyl) phosphonite] and the like.
Examples of amine antioxidants include diphenylamine, N-phenyl-o-toluidine, N-phenyl-m-toluidine, N-phenyl-p-toluidine, bis(2-methylphenyl)amine, bis(3-methyl phenyl)amine, bis(4-methylphenyl)amine, p,p'-dioctyldiphenylamine, N-phenyl-1-naphthylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, p-(p- toluenesulfonylamido)diphenylamine, N,N'-di-2-naphthyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, phenothiazine and the like.
These antioxidants (C) can be used individually or in combination of 2 or more types.

The amount of the non-phenolic antioxidant (C) added is preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the thermoplastic polyimide resin (A), and 0.02 parts by mass or more and 3 parts by mass or less. is more preferable, and 0.05 parts by mass or more and 1 part by mass or less is even more preferable. When the amount of the non-phenolic antioxidant (C) added is at least the above lower limit, the heat aging resistance of the resin composition can be further improved. In addition, if the amount of the non-phenolic antioxidant added is equal to or less than the above upper limit, it is preferable from the viewpoint of balance with other additives and maintenance of physical properties.

Furthermore, the resin composition of the present invention includes, in addition to the above components, other resins, fillers, various additives other than antioxidants, such as ultraviolet absorbers and light stabilizers, within the scope of the present invention. Agents, nucleating agents, coloring agents, lubricants, flame retardants and the like may be added as appropriate.
The content of other resins is not particularly limited, but may be, for example, about 50 parts by mass or less, or may be 30 parts by mass or less, with respect to 100 parts by mass of the thermoplastic polyimide resin (A). The resin in the resin composition is preferably composed of the thermoplastic polyimide resin (A), although it may be in parts by mass or less.

(Melting characteristics)
The resin composition of the present invention is often heated to a high temperature during a soldering step or the like. Therefore, it is necessary to prevent the thermal decomposition of the resin composition from lowering the molecular weight and lowering the physical properties of the resin composition. The change in molecular weight can be tracked using the viscosity of the resin composition in a molten state as an index, and from the viewpoint of suppressing thermal decomposition, it is preferable that the viscosity of the resin composition in a molten state is maintained before and after heating. Specifically, it is preferable to maintain the viscosity of the molten resin before and after the heat treatment from the viewpoint of preventing the melting characteristics from being changed by the measurement.
The resin composition of the present invention preferably has a viscosity retention rate of 70% or more after being heated at 240° C. for 1 hour, more preferably 75% or more, even more preferably 80% or more. The upper limit of the viscosity retention rate is not particularly limited, and is, for example, 110% or less.
In addition, the resin composition of the present invention preferably has a viscosity retention rate of 50% or more after being heated at 260° C. for 1 hour, more preferably 55% or more, and even more preferably 60% or more. The upper limit of the viscosity retention rate is not particularly limited, and may be 100% or less.
The melt viscosity is obtained by preparing a film having a thickness of 200 μm from the resin composition, using the film as a test piece, heat-treating it at 240° C. or 260° C. for 1 hour, and then measuring the apparent viscosity at 340° C. value.

(dielectric properties)
From the viewpoint of reducing transmission loss, the resin composition of the present invention preferably has a low dielectric loss tangent.
Specifically, the dielectric loss tangent of the resin composition is preferably 0.007 or less. From the viewpoint of more effectively reducing transmission loss, the dielectric loss tangent of the resin composition is more preferably 0.006 or less, even more preferably 0.005 or less, and particularly preferably 0.004 or less.

Furthermore, from the viewpoint of stabilizing the dielectric loss tangent before and after heating at a high temperature, it is preferable that the change in the dielectric loss tangent of the resin composition between before and after heating is small. Specifically, the change in dielectric loss tangent after heating at 240 ° C. for 1 hour is preferably 0.0005 or less, more preferably 0.0004 or less, further preferably 0.0003 or less, and particularly 0.0002 or less. preferable. Furthermore, the change in dielectric loss tangent after heating at 260° C. for 1 hour is preferably 0.0007 or less, more preferably 0.0006 or less, still more preferably 0.0005 or less, and particularly preferably 0.0004 or less.
In addition, the dielectric loss tangent is measured by preparing a film having a thickness of 200 μm from the resin composition, using the film as a test piece, and drying it by heating at 150° C. for 12 hours or more in accordance with JIS C2565: 1992. Then, the temperature is 23° C., the frequency It is a value obtained by measuring under the condition of 10 GHz.

<Molded body>
Examples of molded articles formed using the resin composition of the present invention include molded articles having shapes such as films and plates. Among others, the resin composition of the present invention can be suitably used as a film because it has good dielectric properties and heat aging resistance.

The film of the present invention is preferably made of the resin composition described above. Although the thickness of the film is not particularly limited, it is usually 1 to 400 μm, and particularly preferably 30 to 300 μm from the viewpoint of being suitable for use as a film.
In addition, the film is preferably formed so that the anisotropy of physical properties in the machine direction (MD) and its orthogonal direction (TD) is minimized.

Moreover, since the film of the present invention is used as a substrate, it is often heated to a high temperature in a soldering process or the like. Therefore, from the viewpoint of preventing the appearance from being changed due to crystallization during heating, the film is preferably in a crystallized state.
When a film in a crystallized state is used, the relative crystallinity of the film is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, and even more preferably 85% or more. It is particularly preferred that it is 1, and 90% or more is particularly preferred. Also, the upper limit is usually 100%. When the relative crystallinity of the film is at least the above lower limit, it is possible to appropriately prevent changes in appearance due to crystallization during heating.

The relative crystallinity is measured by heating a test piece obtained from the film at a temperature elevation rate of 10 ° C./min using a differential scanning calorimeter (Pyris1 DSC, manufactured by PerkinElmer), and crystal melting obtained at this time. It is obtained by calculation using the following formula (1) from the peak heat quantity (J/g) and the recrystallization peak heat quantity (J/g).
Relative crystallinity (%) = {1-(ΔHc/ΔHm)}×100 (1)
ΔHc: amount of heat (J/g) at the recrystallization peak under the condition of temperature increase of 10°C/min of the film material
ΔHm: amount of heat (J/g) at crystalline melting peak under temperature rising conditions of 10°C/min of film material

When there are multiple recrystallization peaks, the total amount of heat is calculated as ΔHc, and when there are multiple crystal melting peaks, the total amount of heat is calculated as ΔHm. A film with no recrystallization peak (ΔHc = 0 J/g) when measured with a differential scanning calorimeter is a crystallized film, and a film with a recrystallization peak is not completely crystallized. can.
In order to make the relative crystallinity within the above range, for example, the conditions at the time of producing the film may be appropriately adjusted, the details of which will be described later.

(mechanical properties)
The films of the present invention are often heated to high temperatures, such as in soldering processes. Therefore, it is preferable that the film does not crack before and after heating from the viewpoint of preventing the physical properties of the resin composition from decreasing due to thermal decomposition. Specifically, it is preferable that a film having a thickness of 200 μm is heated at 240° C. for 1 hour and then bent at 180° without cracking. Also, it is preferable that the film does not crack completely even when it is heated at 260° C. for 1 hour and then bent at 180°, but in this case, it may partially crack.

<Method for manufacturing molded body>
The method for producing the molded article is not particularly limited, but known methods such as extrusion molding, injection molding, blow molding, vacuum molding, air pressure molding, press molding, etc. can be employed.

In addition, the film may be a uniaxially or biaxially stretched film that is stretched in one direction or two directions. After producing the unstretched film, a method of stretch molding by roll stretching method, tenter stretching method or the like, or a method of integrally performing melt extrusion and stretch molding by inflation method, tubular method or the like can be mentioned.

The molding temperature in the press method or the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics, film-forming properties, etc. of the resin composition used, but is generally 280° C. or higher and 370° C. or lower. For melt-kneading, a commonly used single-screw extruder, twin-screw extruder, kneader, mixer, or the like can be used without any particular limitation.

In the case of molding by a press method or an extrusion casting method using a T-die, the obtained film may be rapidly cooled and collected in an amorphous state, or may be crystallized by slow cooling or heating during casting, or non-crystalline. After being collected in a crystalline state, it may be collected in a crystallized state by heat treatment. In general, amorphous films are excellent in durability and secondary workability, and crystallized films are excellent in heat resistance and stiffness. Preferably, the film of the present invention is a film crystallized as described above.

<Substrate>
The resin composition of the present invention is used for various substrates, and a molded article such as a film made of the resin composition preferably constitutes at least a part of the substrate. Also, the substrate may typically be a circuit board having a circuit. Examples of circuit boards include FPC (Flexible printed circuits) and FCCL (Flexible Cupper Clad Laminate).
In the present invention, as described above, a molded article such as a film has well-balanced performances such as dielectric properties, heat aging resistance, and toughness. Therefore, it satisfies the required properties required for the substrate and is suitably used for the substrate. In particular, in the present invention, since heat aging resistance is improved, even after being heated to a high temperature in a soldering process or the like, cracks and the like are less likely to occur when bent. Therefore, it is particularly suitable for the FPC and FCCL described above.

The present invention provides a laminate. The laminate is a laminate comprising the film of the present invention described above and a copper foil. The laminate may form a circuit and constitute a circuit board. The copper foil is preferably patterned into a predetermined shape by etching or the like in the circuit board to constitute wiring or the like. The thickness of the copper foil is, for example, 1-80 μm, preferably 3-50 μm, more preferably 5-30 μm.

The film of the invention preferably constitutes a base film or a cover film.
The base film serves as the base material of the circuit board, and it is preferable that a copper foil be provided on the base film. A copper foil is generally attached to a base film via an adhesive layer.
Examples of the adhesive layer include, but are not particularly limited to, epoxy-based resin adhesives, acrylic-based resin adhesives, phenol-based resin adhesives, ester-based resin adhesives, and the like.
Alternatively, 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. It may be directly attached to the base film without intervening layers.

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 the base film. The cover film is used by adhering it to a copper foil-provided surface of a base film, which is a base material of a circuit board, or a rigid board.
A 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. In addition, the adhesive layer may be omitted as appropriate. In that case, the cover film may be adhered to the copper foil surface-treated with a surface treatment agent such as a silane coupling agent, or the adhesive layer and the surface treatment agent may be used. It may be directly adhered to the copper foil without an intervening layer.
In addition, the copper foil is generally patterned and partially provided on the base material, but in the part of the base material where the copper foil is not provided, the cover film may be directly adhered to the base material, or the adhesive layer may be applied. It may be attached to the base material via the substrate.

FIG. 1 shows an example of a circuit board provided with 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 comprises a base film 11, a copper foil 12 and a cover film 13. Either one of the base film 11 and the cover film 13 of the circuit board 10 may be made of the film of the present invention, 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 bonded 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.
Also, the cover film 13 is preferably attached to one surface of the base film 11 on which the copper foil 12 is provided 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, or a surface treatment agent such as a silane coupling agent may be used. may be adhered to the copper foil 12 via the

The cover film 13 may be appropriately provided with holes 16 , and similarly the base film 11 may also be provided with holes (not shown). Moreover, although the copper foil 12 is provided only on one side of the base film 11 in FIG. 1 , the copper foil 12 may be provided on both sides of the base film 11 . In addition, although FIG. 1 shows a structure having only one layer of the base film 11 provided with the copper foil 12, the circuit board may be a multi-layer circuit board in which multiple layers of the base film 11 are laminated.

The present invention provides an electronic device having a circuit board. Examples of electronic devices include, but are not limited to, portable electronic devices such as mobile phones, smart phones, electronic notebooks, digital still cameras, and video cameras, electronic paper, televisions, DVD players, various audio devices, car navigation devices, instrument panels, and the like. automotive displays, calculators, printers, scanners, copiers, refrigerators, washing machines and the like.

Examples will be described in more detail below, but the present invention is not limited by these. Various measurements on the raw materials described in this specification, the resin composition of the present invention, and the film formed from the resin composition were carried out as follows.

(1) Melting property The obtained film was placed in a constant temperature bath at 240°C or 260°C for 1 hour and allowed to stand at room temperature (23°C) after heat treatment. The film returned to room temperature was dried at 160 ° C. for 6 hours or more, and the apparent viscosity of the melt at a shear rate of 100 (1 / s) at 340 ° C. was measured using a Koka flow tester (Shimadzu manufactured by Seisakusho Co., Ltd.). Taking the viscosity before heat treatment as 100%, the viscosity retention rate (%) after heat treatment was calculated.

(2) Mechanical Properties The obtained film was placed in a constant temperature bath at 240° C. or 260° C. for 1 hour and allowed to stand at room temperature (23° C.) after heat treatment. When the film returned to room temperature was folded at 180°, the case where cracks or cracks did not occur was rated as "A (very good)", and the case where some cracks occurred was rated as "B (good)". was designated as "C (pооr)".

(3) Dielectric properties The obtained film was placed in a constant temperature bath at 240°C or 260°C for 1 hour, and left at room temperature (23°C) after heat treatment. The film before and after heating was placed in a constant temperature bath at 150° C. for 12 hours or more and dried, and then the dielectric loss tangent was measured at a temperature of 23° C. and a frequency of 10 GHz according to JIS C2565:1992.

(4) Crystal melting temperature For raw material pellets, a differential scanning calorimeter Pyris1 DSC (manufactured by PerkinElmer) is used in accordance with JIS K7121: 2012 at a temperature range of 25 to 380 ° C. and a heating rate of 10 ° C./min. Using a scanning calorimeter Pyris1 DSC (manufactured by PerkinElmer), the crystal melting temperature was obtained from the peak top temperature of the DSC curve detected during the reheating process.

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

(6) Glass transition temperature Raw material pellets were kneaded at 340° C. using a Φ40 mm co-rotating twin-screw extruder, extruded from a T-die, and then cooled with a casting roll at about 200° C. to produce a film with a thickness of 100 μm. . For the obtained film, using a viscoelastic spectrometer DVA-200 (manufactured by IT Keisoku Co., Ltd.), strain 0.1%, frequency 10 Hz, temperature range 20 to 400 in accordance with JIS K7244-4: 1999. The dynamic viscoelasticity was measured under the conditions of °C and a heating rate of 3 °C/min. The temperature at the peak top of the obtained tensile loss coefficient (tan δ) was defined as the glass transition temperature.

[Thermoplastic polyimide resin (A)]
(A-1): Thermoplastic polyimide resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: Surprim 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 viscoelasticity measurement): 208°C)

[Phenolic antioxidant (B)]
(B-1): Hindered phenolic antioxidant (manufactured by BASF, Irganox 1010, weight average molecular weight: 1178)
(B-2): Semi-hindered phenolic antioxidant (Sumitomo Chemical Co., Ltd., SUMILIZER GA-80, weight average molecular weight: 741)
(B-3): Semi-hindered phenolic antioxidant (manufactured by BASF, Irganox245, weight average molecular weight: 587)
(B-4): Semi-hindered phenol phosphorus antioxidant (Sumitomo Chemical Co., Ltd., SUMILIZER GP, weight average molecular weight: 661)

[Non-phenolic antioxidant (C)]
(C-1): Sulfur-based antioxidant (Sumitomo Chemical Co., Ltd., SUMILIZER TP-D, weight average molecular weight: 1162)
(C-2): phosphorus antioxidant (manufactured by BASF, Irgafos 168, weight average molecular weight: 647)

(Example 1)
The thermoplastic polyimide resin (A-1) was supplied to a Plastograph mixer manufactured by Toyo Seiki Co., Ltd., and melted and kneaded for 3 minutes at a temperature of 340 ° C. and a rotation speed of 40 rpm, and then a phenolic antioxidant (B-1). (A-1) was supplied so as to be 0.5 parts by mass with respect to 100 parts by mass, and melt-kneaded for 2 minutes at a temperature of 330° C. and a rotation speed of 40 rpm to obtain a resin composition. It was sandwiched between two metal plates, press-molded under the conditions of temperature = 340°C, pressure = 3 MPa, molding time = 10 seconds, and then slowly cooled with water to 200°C or less to form a film with a thickness of 200 μm. . The above evaluation was performed on the obtained film. Table 1 shows the results.

(Example 2)
A film was produced and evaluated in the same manner as in Example 1, except that the phenolic antioxidant (B-2) was used instead of the phenolic antioxidant (B-1). Table 1 shows the results.

(Example 3)
A film was produced and evaluated in the same manner as in Example 1, except that the phenolic antioxidant (B-3) was used instead of the phenolic antioxidant (B-1). Table 1 shows the results.

(Example 4)
A film was produced and evaluated in the same manner as in Example 1, except that the phenolic antioxidant (B-4) was used instead of the phenolic antioxidant (B-1). Table 1 shows the results.

(Example 5)
In addition to the phenolic antioxidant (B-1), non-phenolic antioxidant (C-1) was added 0.5 parts by weight per 100 parts by weight of the thermoplastic polyimide resin (A-1) Examples A film was produced and evaluated in the same manner as in 1. Table 1 shows the results.

(Example 6)
In addition to the phenolic antioxidant (B-2), non-phenolic antioxidant (C-1) was added 0.5 parts by weight per 100 parts by weight of the thermoplastic polyimide resin (A-1) Example A film was produced and evaluated in the same manner as in 2. Table 1 shows the results.

(Example 7)
In addition to the phenolic antioxidant (B-1), non-phenolic antioxidant (C-2) was added 0.5 parts by weight per 100 parts by weight of the thermoplastic polyimide resin (A-1) Example A film was produced and evaluated in the same manner as in 1. Table 1 shows the results.

(Comparative example 1)
A film was produced and evaluated in the same manner as in Example 1, except that the phenolic antioxidant (B-1) was not used. Table 1 shows the results.

(Comparative example 2)
A film was produced and evaluated in the same manner as in Example 1, except that the non-phenolic antioxidant (C-1) was used instead of the phenolic antioxidant (B-1). Table 1 shows the results.

(Comparative Example 3)
A film was produced and evaluated in the same manner as in Example 1, except that the non-phenolic antioxidant (C-2) was used instead of the phenolic antioxidant (B-1). Table 1 shows the results.

In the resin compositions of Examples 1 to 4, the decrease in melt viscosity due to heating was suppressed by adding the phenolic antioxidant (B). This is because the thermal decomposition reaction of the tetracarboxylic acid component (a-1) and the aliphatic diamine component (a-2) with low thermal stability in the thermoplastic polyimide resin (A-1) was suppressed. It is believed that this is because the decrease in melt viscosity due to the decrease in the molecular weight of the plastic polyimide resin (A-1) was suppressed.
Since the decrease in molecular weight due to thermal decomposition of the thermoplastic polyimide resin (A-1) was suppressed, in Examples 1 to 4, it was possible to suppress the decrease in mechanical properties and dielectric properties after heating.
Further, in the resin compositions of Examples 5 to 7, the phenolic antioxidant (B) and the non-phenolic antioxidant (C), especially the sulfur-based antioxidant (C-1) were used in combination. It was possible to substantially maintain the physical properties of the film before and after.

REFERENCE SIGNS LIST 10 circuit board 11 base film 12 copper foil 13 cover film 14 first adhesive layer 15 second adhesive layer 16 hole

Claims (21)

A resin composition containing a thermoplastic polyimide resin (A) and a phenolic antioxidant (B). The resin according to claim 1, wherein the thermoplastic polyimide resin (A) has repeating units derived from the tetracarboxylic acid component (a-1) and repeating units derived from the aliphatic diamine component (a-2). Composition. 3. The resin composition 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. 4. The resin composition according to claim 2, wherein the aliphatic diamine component (a-2) contains at least an alicyclic diamine. The resin composition according to any one of claims 2 to 4, wherein the aliphatic diamine component (a-2) comprises at least one of a linear aliphatic diamine and a branched aliphatic diamine and an alicyclic diamine. thing. The ratio of the content of at least one of a linear aliphatic diamine and a branched aliphatic diamine to the alicyclic diamine is, on a molar basis, at least one of a linear aliphatic diamine and a branched aliphatic diamine: alicyclic The resin composition according to claim 5, wherein the diamine is in the range of 1:99 to 90:10. The resin composition according to any one of claims 4 to 6, wherein the alicyclic diamine is 1,3-bis(aminomethyl)cyclohexane. The resin composition according to any one of claims 1 to 7, wherein the thermoplastic polyimide resin (A) has crystallinity. Any one of claims 1 to 8, wherein the content of the phenolic antioxidant (B) is 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the thermoplastic polyimide resin (A). The resin composition according to Item. The resin composition according to any one of claims 1 to 9, wherein the phenolic antioxidant (B) is a polyfunctional phenolic antioxidant. The resin composition according to any one of claims 1 to 10, wherein the phenolic antioxidant (B) contains at least one of a hindered phenolic antioxidant and a semi-hindered phenolic antioxidant. The resin composition according to any one of claims 1 to 11, wherein the phenolic antioxidant (B) has a weight average molecular weight of 300 or more. Any one of claims 1 to 12, further comprising at least one non-phenolic antioxidant (C) selected from the group consisting of sulfur antioxidants, phosphorus antioxidants and amine antioxidants. The resin composition according to Item. The resin composition according to any one of claims 1 to 13, which has a viscosity retention rate of 70% or more after being heated at 240°C for 1 hour. The resin composition according to any one of claims 1 to 14, which has a viscosity retention rate of 50% or more after being heated at 260°C for 1 hour. The resin composition according to any one of claims 1 to 15, which has a dielectric loss tangent of 0.007 or less at a frequency of 10 GHz and a thickness of 200 µm, as measured according to JIS C2565:1992. A film made of the resin composition according to any one of claims 1 to 16. 18. The film according to claim 17, which is a cover film or base film for a substrate. A laminate obtained by laminating the film according to claim 17 or 18 and a copper foil. A circuit board obtained by forming a circuit on the laminate according to claim 19 . An electronic device comprising the circuit board according to claim 20.

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