JP2022099778A - Polyimide composition, resin film, laminate, cover lay film, copper foil with resin, metal-clad laminate, and circuit board - Google Patents

Abstract

To provide a polyimide composition which enables formation of a resin film that uses thermoplastic polyimide and has both a low dielectric loss tangent and excellent adhesion.SOLUTION: A polyimide composition contains (A) thermoplastic polyimide and (B) a polystyrene elastomer resin having an acid value of 10 mgKOH/g or less, in which a content of the component (B) with respect to 100 pts.wt. of the component (A) is 10 pts.wt. or more and 100 pts.wt. or less. A thermoplastic resin layer obtained by turning the polyimide composition into a film has a dielectric loss tangent (Tanδ) at 10 GHz measured by a split post dielectric resonator (SPDR) after moisture conditioning under constant temperature/humidity conditions of 23°C and 50%RH for 24 hours of 0.0020 or less.SELECTED DRAWING: None

Description

The present invention relates to a polyimide composition, a resin film, a laminate, a coverlay film, a copper foil with a resin, a metal-clad laminate, and a circuit board, which are useful as an adhesive in a circuit board such as a printed wiring board.

In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, a flexible printed wiring board (FPC) that is thin and lightweight, has flexibility, and has excellent durability even after repeated bending. The demand for Circuits) is increasing. Since FPC can be mounted three-dimensionally and at high density even in a limited space, it can be used for wiring of moving parts of electronic devices such as HDDs, DVDs, and mobile phones, and for parts such as cables and connectors. It is expanding.

In addition to the above-mentioned high density, the high performance of the equipment has advanced, so it is also necessary to cope with the high frequency of the transmission signal. In information processing and information communication, efforts are being made to increase the transmission frequency in order to transmit and process large volumes of information, and the printed circuit board material has a transmission loss due to the thinning of the insulating layer and the improvement of the dielectric properties of the insulating layer. Is required to decrease. In the future, it will be required for the insulating layer (including the adhesive layer) constituting the FPC to further reduce the transmission loss and cope with the increase in frequency. Regarding the improvement of the dielectric property of the printed circuit board material, an adhesive composition containing an acid-modified polystyrene elastomer resin, a carbodiimide resin and an epoxy resin has been proposed (for example, Patent Document 1). However, according to Patent Document 1, if the acid value of the acid-modified polystyrene elastomer resin is low, the compatibility with other components is lowered and the adhesive strength is not developed. Further, regarding an adhesive for fixing a semiconductor wafer to a support when polishing, an adhesive composition containing an acid-modified polystyrene elastomer resin has been proposed (for example, Patent Document 2).

By the way, a thermoplastic polyimide made from a diamine compound derived from an aliphatic diamine such as fatty acid (dimeric fatty acid) is reacted with an amino compound having at least two primary amino groups as functional groups. It has been proposed to apply the crosslinked polyimide resin thus obtained to the adhesive layer of a coverlay film (for example, Patent Document 3). In the examples of Patent Document 3, it is also disclosed that scaly talc is blended with a thermoplastic polyimide composition using an aliphatic diamine as a raw material. Here, fatty acid is subjected to a deal-alder reaction using natural fatty acids such as soybean oil fatty acid, tall oil fatty acid, rapeseed oil fatty acid and the like and purified oleic acid, linoleic acid, linolenic acid, erucic acid and the like as raw materials. It is known that a polybasic acid compound derived from dimer acid, which is a dimerized fatty acid obtained in the above, can be obtained as a composition of a raw material fatty acid or a fatty acid of trimerization or higher (for example, patent). Document 4).

Japanese Patent No. 6705456 International release WO 2013/153904 Japanese Patent No. 5777944 Japanese Unexamined Patent Publication No. 2017-137375

Thermoplastic polyimide made from an aliphatic diamine is a resin material useful as an adhesive because it is soluble in a solvent, has excellent adhesiveness, and has good handleability. In order to cope with this, in addition to satisfying the above-mentioned characteristics, further low dielectric loss tangent is required.

Therefore, an object of the present invention is to provide a polyimide composition using thermoplastic polyimide, which can form a resin film having both low dielectric loss tangent and excellent adhesiveness.

The polyimide composition of the present invention has the following components (A) and (B);
(A) thermoplastic polyimide, and (B) polystyrene elastomer resin having an acid value of 10 mgKOH / g or less.
The content of the component (B) with respect to 100 parts by weight of the component (A) is within the range of 10 parts by weight or more and 100 parts by weight or less.

In the polyimide composition of the present invention, the content ratio of the styrene unit in the component (B) may be in the range of 10% by weight or more and 65% by weight or less.

In the polyimide composition of the present invention, the thermoplastic polyimide may be obtained by reacting a tetracarboxylic acid anhydride component with a diamine component, and 40 mol of an aliphatic diamine is added to the diamine component. It may be contained in% or more.

The polyimide composition of the present invention contains a dimerdiamine as a main component, wherein the aliphatic diamine is composed of a primary aminomethyl group or an amino group in which two terminal carboxylic acid groups of dimer acid are substituted. May be.

The polyimide composition of the present invention may further contain an amino compound having at least two primary amino groups as functional groups.

The resin film of the present invention is a resin film containing a thermoplastic resin layer.
The thermoplastic resin layer has the following components (A) and (B);
(A) Thermoplastic polyimide,
And (B) a polystyrene elastomer resin having an acid value of 10 mgKOH / g or less,
The content of the component (B) is in the range of 10 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the component (A).

In the resin film of the present invention, the thermoplastic resin layer is dielectric at 10 GHz measured by a split post dielectric resonator (SPDR) after humidity adjustment for 24 hours under constant temperature and humidity conditions of 23 ° C. and 50% RH. The orthogonal contact (Tan δ) may be 0.0020 or less.

The laminate of the present invention is a laminate having a substrate and an adhesive layer laminated on at least one surface of the substrate, and the adhesive layer is characterized by being made of the resin film. And.

The coverlay film of the present invention is a coverlay film having a coverlay film material layer and an adhesive layer laminated on the coverlay film material layer, and the adhesive layer is made from the above resin film. It is characterized by becoming.

The copper foil with resin of the present invention is a copper foil with resin in which an adhesive layer and a copper foil are laminated, and the adhesive layer is made of the resin film.

The metal-clad laminate of the present invention is a metal-clad laminate having an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, and at least one layer of the insulating resin layer is It is characterized by being made of the above resin film.

The circuit board of the present invention is formed by wiring processing the metal layer of the metal-clad laminate.

Since the polyimide composition of the present invention contains a thermoplastic polyimide and a polystyrene elastomer resin having a specific acid value, a resin having excellent adhesive strength having practically sufficient peel strength while maintaining a low dielectric positive contact. A film can be formed. Therefore, the polyimide composition and the resin film of the present invention can be particularly preferably used as a circuit board material such as FPC in an electronic device that requires high-speed signal transmission, for example. Further, by improving the dielectric property of the resin film, it becomes possible to apply it to a direct conversion receiver. Further, since the peel strength of the resin film can be improved, it can be applied to electronic devices having any structure as a highly reliable low-dielectric adhesive.

Hereinafter, embodiments of the present invention will be described.

[Polyimide composition]
The polyimide composition according to the embodiment of the present invention has the following components (A) and (B);
(A) thermoplastic polyimide, and (B) polystyrene elastomer resin having an acid value of 10 mgKOH / g or less.
Contains.

<(A) component: thermoplastic polyimide>
The thermoplastic polyimide of the component (A) is a thermoplastic polyimide having solvent solubility, and is an imidized precursor polyamic acid obtained by reacting a tetracarboxylic acid anhydride component with a diamine component. .. The "thermoplastic polyimide" is a polyimide that is generally softened by heating, solidified by cooling, and can be repeated, and the glass transition temperature (Tg) can be clearly confirmed. It means a polyimide in which the glass transition temperature can be clearly confirmed in a temperature range of less than 150 ° C. Further, from the viewpoint of thermal pressure bonding at low temperature, polyimide is preferable because the glass transition temperature can be clearly confirmed in a temperature range of less than 100 ° C., and storage at 30 ° C. measured using a dynamic viscoelastic modulus measuring device (DMA) is preferable. A polyimide having an elastic modulus of 1.0 × 10 ⁸ Pa or more and a storage elastic modulus of less than 3.0 × 10 ⁷ Pa at a glass transition temperature of + 30 ° C. is more preferable. The "non-thermoplastic polyimide" is a polyimide that generally does not soften or show adhesiveness even when heated, but in the present invention, it is measured using a dynamic viscoelastic modulus measuring device (DMA). A polyimide having a storage elastic modulus of 1.0 × 10 ⁹ Pa or more at ° C. and a storage elastic modulus of 3.0 × 10 ⁸ Pa or more at 300 ° C.

(Tetracarboxylic acid anhydride component)
The thermoplastic polyimide of the component (A) can contain a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride generally used for the thermoplastic polyimide without particular limitation, but for all tetracarboxylic acid residues. Therefore, it is preferable to contain 90 mol% or more of the tetracarboxylic acid residue derived from the tetracarboxylic acid anhydride represented by the following general formula (1) in total. By containing a total of 90 mol% or more of tetracarboxylic acid residues derived from the tetracarboxylic acid anhydride represented by the following general formula (1) with respect to all tetracarboxylic acid residues, the polyimide is flexible. It is preferable that both properties and heat resistance are easy to achieve. If the total amount of tetracarboxylic acid residues derived from the tetracarboxylic acid anhydride represented by the following general formula (1) is less than 90 mol%, the solvent solubility of the polyimide tends to decrease.

In the general formula (1), X represents a single bond or a divalent group selected from the following formula.

In the above equation, Z indicates -C ₆ H ₄ -,-(CH ₂ ) n- or -CH ₂ -CH (-OC (= O) -CH ₃ ) -CH _2- , where n is 1. Indicates an integer of ~ 20.

Examples of the tetracarboxylic acid anhydride represented by the general formula (1) include 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), 3,3', 4,4'. -Benzophenone tetracarboxylic acid dianhydride (BTDA), 3,3', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride (DSDA), 4,4'-oxydiphthalic acid anhydride (ODPA), 4,4 '-(Hexafluoroisopropylidene) diphthalic acid anhydride (6FDA), 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), p-phenylene bis (trimerit) Acid monoesteric acid anhydride) (TAHQ), ethylene glycol bisamhydrotrimethylate (TMEG) and the like can be mentioned. Among these, especially when 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) is used, the adhesiveness of the polyimide can be improved, and the ketone group present in the molecular skeleton can be used. The amino group of the amino compound for forming a crosslink, which will be described later, may react to form a C = N bond, and the effect of improving heat resistance is likely to be exhibited. From this point of view, the tetravalent tetracarboxylic acid residue (BTDA residue) derived from BTDA is preferably 50 mol% or more, more preferably 60 mol% or more, based on all the tetracarboxylic acid residues. May contain.

The thermoplastic polyimide of the component (A) contains a tetracarboxylic acid residue derived from an acid anhydride other than the tetracarboxylic acid anhydride represented by the above general formula (1) as long as the effect of the invention is not impaired. can do. The tetracarboxylic acid residue is not particularly limited, but for example, pyromellitic acid dianhydride, 2,3', 3,4'-biphenyltetracarboxylic acid dianhydride, 2,2', 3 , 3'-or 2,3,3', 4'-benzophenone tetracarboxylic acid dianhydride, 2,3', 3,4'-diphenyl ether tetracarboxylic acid dianhydride, bis (2,3-dicarboxyphenyl) ) Ether dianhydride, 3,3'', 4,4''-, 2,3,3'', 4''-or 2,2'',3,3''-p-terphenyltetracarboxylic Acid dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) methane dianhydride, Bis (2,3- or 3,4-dicarboxyphenyl) sulfonate dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride, 1,2,7, 8-1,2,6,7-or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 2,2-bis (3,4-Dicarboxyphenyl) Tetrafluoropropane dianhydride 2,3,5,6-cyclohexane dianhydride 1,2,5,6-naphthalene tetracarboxylic acid dianhydride 1,4,5 , 8-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1 , 2,5,6-Tetracarboxylic acid dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-Tetracarboxylic acid dianhydride, 2,3,6,7-( Or 1,4,5,8-) Tetrachloronaphthalene-1,4,5,8-(or 2,3,6,7-) Tetracarboxylic acid dianhydride 2,3,8,9-3 , 4,9,10-, 4,5,10,11-or 5,6,11,12-perylene-tetracarboxylic acid dianhydride, cyclopentane-1,2,3,4-tetracarboxylic acid dianhydride, Pyrazine-2,3,5,6-tetracarboxylic acid dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic acid dianhydride, thiophene-2,3,4,5-tetracarboxylic acid dianhydride Examples thereof include tetracarboxylic acid residues derived from aromatic tetracarboxylic acid dianhydrides such as anhydrous, 4,4'-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride.

(Diamine component)
As the thermoplastic polyimide of the component (A), it is preferable to use a diamine component containing an aliphatic diamine in an amount of preferably 40 mol% or more, more preferably 60 mol% or more, based on the total diamine component as a raw material. That is, the thermoplastic polyimide of the component (A) may contain, preferably 40 mol% or more, more preferably 60 mol% or more of the diamine residue derived from the aliphatic diamine with respect to all the diamine residues. good. By containing the diamine residue derived from the aliphatic diamine in the above amount, the dielectric property of the polyimide is improved, and the thermal pressure bonding property is improved and lowered by lowering the glass transition temperature of the polyimide (lower Tg). Internal stress due to elastic modulus can be relaxed. If the diamine residue derived from the aliphatic diamine is less than 40 mol% with respect to all the diamine residues, the effect of improving the dielectric loss tangent and the thermocompression bonding characteristics may not be sufficiently obtained. Here, as the aliphatic diamine, for example, a dimer diamine composition containing dimer diamine as a main component, in which two terminal carboxylic acid groups of dimer acid are substituted with a primary aminomethyl group or an amino group, hexamethylene. Diamines, dodecanediamines, cyclohexanediamines, polyoxyalkyleneamines, 4,4-diaminodicyclohexylmethane and the like can be used, with diamine diamine compositions being particularly preferred.

(Diamine Diamine Composition)
The diamine diamine composition contains the following component (a) as a main component, and the amounts of the components (b) and (c) are controlled.

(A) Dimer diamine;
The diamine diamine of the component (a) means that the two terminal carboxylic acid groups (-COOH) of the dimer acid are replaced with a primary aminomethyl group ( _-CH2 -NH ₂ ) or an amino group (-NH ₂ ). Means a diamine that has been made. Fatty acid is a known dibasic acid obtained by the intermolecular polymerization reaction of unsaturated fatty acids, and its industrial production process is almost standardized in the industry, and unsaturated fatty acids having 11 to 22 carbon atoms are clay-catalyzed. It is obtained by quantifying it with the like. The main component of industrially obtained dimer acid is a dibasic acid having 36 carbon atoms obtained by dimerizing an unsaturated fatty acid having 18 carbon atoms such as oleic acid, linolenic acid and linolenic acid. Depending on the degree, it contains an arbitrary amount of monomeric acid (18 carbon atoms), trimeric acid (54 carbon atoms), and other polymerized fatty acids having 20 to 54 carbon atoms. Further, although the double bond remains after the dimerization reaction, in the present invention, the dimer acid is also included in which the degree of unsaturation is further reduced by the hydrogenation reaction. The dimerdiamine of the component (a) replaces the terminal carboxylic acid group of the dibasic acid compound in the range of 18 to 54 carbon atoms, preferably 22 to 44 carbon atoms with a primary aminomethyl group or an amino group. It can be defined as a diamine compound obtained.

As a characteristic of dimer diamine, the property derived from the skeleton of dimer acid can be imparted. That is, since dimer diamine is an aliphatic of macromolecules having a molecular weight of about 560 to 620, the molar volume of the molecule can be increased and the polar groups of polyimide can be relatively reduced. It is considered that such a characteristic of the dimer acid type diamine contributes to improving the dielectric property by reducing the relative permittivity and the dielectric loss tangent while suppressing the decrease in the heat resistance of the polyimide. In addition, since it has two freely moving hydrophobic chains having 7 to 9 carbon atoms and two chain-like aliphatic amino groups having a length close to 18 carbon atoms, it not only gives flexibility to the polyimide, but also gives the polyimide flexibility. Since the polyimide can have an asymmetrical chemical structure or a non-planar chemical structure, it is considered that the polyimide can be made to have a low dielectric constant and a low dielectric constant tangent.

As the diamine diamine composition, the diamine diamine content of the component (a) is increased to 96% by weight or more, preferably 97% by weight or more, more preferably 98% by weight or more by a purification method such as molecular distillation. That's good. By setting the diamine diamine content of the component (a) to 96% by weight or more, it is possible to suppress the spread of the molecular weight distribution of the polyimide. If technically possible, it is best that all (100% by weight) of the diamine diamine composition is composed of the diamine diamine of the component (a).

(B) A monoamine compound obtained by substituting a terminal carboxylic acid group of a monobasic acid compound having 10 to 40 carbon atoms with a primary aminomethyl group or an amino group;
The monobasic acid compound in the range of 10 to 40 carbon atoms is a monobasic unsaturated fatty acid in the range of 10 to 20 carbon atoms derived from the raw material of dimer acid, and a by-product during the production of dimer acid. It is a mixture of monobasic acid compounds in the range of 21 to 40 carbon atoms. The monoamine compound is obtained by substituting the terminal carboxylic acid group of these monobasic acid compounds with a primary aminomethyl group or an amino group.

The monoamine compound of the component (b) is a component that suppresses an increase in the molecular weight of polyimide. During the polymerization of polyamic acid or polyimide, the monofunctional amino group of the monoamine compound reacts with the terminal acid anhydride group of the polyamic acid or polyimide to seal the terminal acid anhydride group, and the molecular weight of the polyamic acid or polyimide is sealed. Suppress the increase.

(C) An amine compound obtained by substituting a terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group in the range of 41 to 80 carbon atoms with a primary aminomethyl group or an amino group (however, the dimer). (Excluding diamine);
The polybasic acid compound having a hydrocarbon group in the range of 41 to 80 carbon atoms is mainly composed of a tribasic acid compound in the range of 41 to 80 carbon atoms, which is a by-product during the production of dimer acid. It is a polybasic acid compound. Further, it may contain a polymerized fatty acid other than fatty acid having 41 to 80 carbon atoms. The amine compound is obtained by substituting the terminal carboxylic acid group of these polybasic acid compounds with a primary aminomethyl group or an amino group.

The amine compound of the component (c) is a component that promotes an increase in the molecular weight of polyimide. A trifunctional or higher amino group containing a triamine derived from trimeric acid as a main component reacts with a polyamic acid or a terminal acid anhydride group of polyimide to rapidly increase the molecular weight of polyimide. Further, an amine compound derived from a polymerized fatty acid other than dimer acid having 41 to 80 carbon atoms also increases the molecular weight of the polyimide and causes gelation of the polyamic acid or the polyimide.

In the above diamine diamine composition, when quantifying each component by measurement using gel permeation chromatography (GPC), it is easy to confirm the peak start, peak top and peak end of each component of the diamine diamine composition. In addition, a sample of the diamine diamine composition treated with anhydrous acetic acid and pyridine is used, and cyclohexanone is used as an internal standard substance. Using the sample thus prepared, each component is quantified by the area percent of the GPC chromatogram. The peak start and peak end of each component are set to the minimum value of each peak curve, and the area percentage of the chromatogram can be calculated based on this.

Further, in the dimer diamine composition used in the present invention, the total area of the components (b) and (c) is 4% or less, preferably less than 4%, in terms of the area percentage of the chromatogram obtained by GPC measurement. By setting the total of the components (b) and (c) to 4% or less, it is possible to suppress the spread of the molecular weight distribution of the polyimide.

The area percentage of the chromatogram of the component (b) is preferably 3% or less, more preferably 2% or less, still more preferably 1% or less. By setting it in such a range, it is possible to suppress a decrease in the molecular weight of the polyimide, and further widen the range of the molar ratio of the tetracarboxylic acid anhydride component and the diamine component. The component (b) may not be contained in the diamine diamine composition.

The area percentage of the chromatogram of the component (c) is 2% or less, preferably 1.8% or less, and more preferably 1.5% or less. Within such a range, it is possible to suppress a rapid increase in the molecular weight of the polyimide, and further suppress an increase in the dielectric loss tangent of the resin film at a wide frequency range. The component (c) may not be contained in the diamine diamine composition.

When the area percent ratio (b / c) of the chromatograms of the components (b) and (c) is 1 or more, the molar ratio of the tetracarboxylic acid anhydride component and the diamine component (tetracarboxylic acid anhydride component /). The diamine component) is preferably 0.97 or more and less than 1.0, and such a molar ratio makes it easier to control the molecular weight of the polyimide.

When the area percent ratio (b / c) of the components (b) and (c) in the chromatogram is less than 1, the molar ratio of the tetracarboxylic acid anhydride component and the diamine component (tetracarboxylic acid anhydride component). The / diamine component) is preferably 0.97 or more and 1.1 or less, and by setting such a molar ratio, it becomes easier to control the molecular weight of the polyimide.

The weight average molecular weight of the polyimide is preferably in the range of, for example, 10,000 to 200,000. Further, for example, when applied as an adhesive for FPC, the weight average molecular weight of the polyimide is more preferably in the range of 20,000 to 150,000, and further preferably in the range of 40,000 to 150,000. When the weight average molecular weight of the polyimide is less than 20,000, the flow resistance tends to deteriorate. On the other hand, when the weight average molecular weight of polyimide exceeds 150,000, the viscosity increases excessively and becomes insoluble in a solvent, and defects such as uneven thickness of the adhesive layer and streaks tend to occur during coating work. become.

The diamine diamine composition is preferably purified for the purpose of reducing the component (a) other than the diamine diamine. The purification method is not particularly limited, but a known method such as a distillation method or precipitation purification is preferable. The diamine diamine composition before purification can be obtained as a commercially available product, and examples thereof include PRIAMINE 1073 (trade name), PRIAMINE 1074 (trade name), and PRIAMINE 1075 (trade name) manufactured by Croda Japan.

Examples of the diamine compound other than the aliphatic diamine used for the polyimide include aromatic diamine compounds. Specific examples thereof include 1,4-diaminobenzene (p-PDA; paraphenylenediamine), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-n-. Propyl-4,4'-diaminobiphenyl (m-NPB), 4-aminophenyl-4'-aminobenzoate (APAB), 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [ 4- (3-Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) biphenyl, bis [1- (3-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) phenyl] methane , Bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy)] benzophenone, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2- Bis- [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 3,3'-dimethyl-4,4'- Diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3''-diamino-p-terphenyl, 4,4'-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4'-[1,3-phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t-butylphenyl) ether, bis (p-β) -Methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2 , 6-diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m -Xylylene diamine, p-xylylene diamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2'-methoxy-4, 4'-Diaminobenzanilide, 4,4'-Zia Minovensanilide, 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene, 6-amino-2- (4-aminophenoxy) benzoxazole, 1,3-bis (3-aminophenoxy) ) Examples thereof include diamine compounds such as benzene.

The polyimide can be produced by reacting the above-mentioned tetracarboxylic acid anhydride component and the diamine component in a solvent to generate a polyamic acid, and then heating and closing the ring. For example, a polyimide precursor is obtained by dissolving a tetracarboxylic acid anhydride component and a diamine component in an organic solvent in approximately equimolar amounts, stirring at a temperature in the range of 0 to 100 ° C. for 30 minutes to 24 hours, and carrying out a polymerization reaction. Polyamic acid is obtained. In the reaction, the reaction components are dissolved in the organic solvent so that the precursor to be produced is in the range of 5 to 50% by weight, preferably in the range of 10 to 40% by weight. Examples of the organic solvent used in the polymerization reaction include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2 -Butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethylsulfate, cyclohexanone, methylcyclohexane, dioxane, tetrahydrofuran, diglime, triglime, methanol, ethanol, benzyl alcohol, cresol and the like can be mentioned. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can be used in combination. The amount of such an organic solvent used is not particularly limited, but it should be adjusted so that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 50% by weight. Is preferable.

The synthesized polyamic acid is usually advantageous to be used as a reaction solvent solution, but can be concentrated, diluted or replaced with another organic solvent if necessary. In addition, polyamic acid is generally excellent in solvent solubility, and is therefore advantageously used. The viscosity of the polyamic acid solution is preferably in the range of 500 cps to 100,000 cps. If it is out of this range, defects such as uneven thickness and streaks are likely to occur in the film during coating work by a coater or the like.

The method of imidizing the polyamic acid to form the polyimide is not particularly limited, and for example, a heat treatment such as heating in the solvent at a temperature in the range of 80 to 400 ° C. for 1 to 24 hours is preferably adopted. Will be done. Further, the temperature may be heated under a constant temperature condition, or the temperature may be changed in the middle of the process.

In the thermoplastic polyimide of the component (A), select the types of the tetracarboxylic acid anhydride component and the diamine component, and the molar ratio of each when two or more types of the tetracarboxylic acid anhydride component or the diamine component are applied. Therefore, the dielectric property, the thermal expansion coefficient, the tensile elasticity, the glass transition temperature, and the like can be controlled. Further, in the thermoplastic polyimide of the component (A), when a plurality of structural units of the polyimide are present, it may exist as a block or may exist at random, but it is preferable that it exists at random.

The imide group concentration of the thermoplastic polyimide of the component (A) is preferably 22% by weight or less, more preferably 20% by weight or less. Here, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide base portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 22% by weight, the molecular weight of the resin itself becomes small, the low moisture absorption property deteriorates due to the increase in polar groups, and the Tg and the tensile elastic modulus increase.

The thermoplastic polyimide of the component (A) is most preferably a completely imidized structure. However, a part of the polyimide may be an amic acid. The imidization rate is determined by measuring the infrared absorption spectrum of the polyimide thin film by the single reflection ATR method using a Fourier transform infrared spectrophotometer (commercially available product: manufactured by Nippon Spectroscopy Co., Ltd., trade name; FT / IR620). It can be calculated from the absorbance of C = O expansion and contraction derived from the imide group of 1780 cm ^-1 with the benzene ring absorber near 1015 cm ^-1 as a reference.

<Component (B): Polystyrene elastomer resin>
The polystyrene elastomer resin of the component (B) is a copolymer of styrene or a derivative thereof and a conjugated diene compound, and contains a hydrogenated agent thereof. Here, the styrene or a derivative thereof is not particularly limited, and examples thereof include styrene, methylstyrene, butylstyrene, divinylbenzene, and vinyltoluene. The conjugated diene compound is not particularly limited, and examples thereof include butadiene, isoprene, and 1,3-pentadiene.
Further, it is preferable that the polystyrene elastomer resin is hydrogenated. Due to the addition of hydrogen, the stability against heat is further improved, deterioration such as decomposition and polymerization is less likely to occur, and the aliphatic property is enhanced, and the compatibility with the thermoplastic polyimide of the component (A) is improved. Will increase.

The copolymer structure of the polystyrene elastomer resin of the component (B) may be a block structure or a random structure. Preferred specific examples of the polystyrene elastomer resin include styrene-butadiene-styrene block copolymer (SBS), styrene-butadiene-butylene-styrene block copolymer (SBBS), and styrene-ethylene-butylene-styrene block copolymer (SEBS). ), Styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), and the like, but the present invention is not limited thereto.

The acid value of the polystyrene elastomer resin of the component (B) is 10 mgKOH / g or less, preferably 1 mgKOH / g or less, and more preferably 0 mgKOH / g. By blending the polystyrene elastomer resin having an acid value of 10 mgKOH / g or less with the polyimide composition, the dielectric loss tangent when the resin film is formed can be lowered and good peel strength can be maintained. On the other hand, when the acid value exceeds 10 mgKOH / g, the dielectric property deteriorates due to the increase in polar groups, the compatibility with the component (A) deteriorates, and the adhesion when forming the resin film deteriorates. .. Therefore, the lower the acid value, the better, and the one without acid denaturation (that is, the one having an acid value of 0 mgKOH / g) is the most suitable as the component (B) of the present invention. In the present invention, since the thermoplastic polyimide of the component (A) can exhibit excellent adhesiveness when it contains a residue derived from an aliphatic diamine, it is not acid-modified (that is, it is aliphatic-like). Even if a polystyrene elastomer resin (which has strong properties) is used, it is possible to avoid a decrease in adhesive strength as is a concern in Patent Document 1.

The polystyrene elastomer resin as the component (B) preferably has a content ratio of the styrene unit [-CH ₂ CH (C ₆ H ₅ )-] in the range of 10% by weight or more and 65% by weight or less, preferably 20% by weight or more. It is more preferably in the range of 65% by weight or less, and most preferably in the range of 30% by weight or more and 60% by weight or less. When the content ratio of the styrene unit in the polystyrene elastomer resin is less than 10% by weight, the elastic coefficient of the resin deteriorates and the handleability as a film deteriorates, and when it exceeds 65% by weight, the resin becomes rigid and the adhesive becomes adhesive. In addition to being difficult to use as a plastic, the amount of rubber component in the polystyrene elastomer resin is reduced, which leads to deterioration of the dielectric property.
Further, when the content ratio of the styrene unit is within the above range, the ratio of the aromatic ring in the resin film becomes high, so that via holes (through holes) and via holes are formed by laser processing in the process of manufacturing the circuit board using the resin film. When forming a blind via hole, it is possible to enhance the absorption in the ultraviolet region, and it is possible to further improve the laser processability.

The weight average molecular weight of the polystyrene elastomer resin as the component (B) is preferably in the range of, for example, 50,000 to 300,000, more preferably in the range of 80,000 to 270,000. If the weight average molecular weight of the component (B) is lower than the above range, the effect of improving the dielectric properties may be low, and conversely, if it is high, the viscosity of the polyimide composition becomes high, and a resin film can be produced. It can be difficult.

As the polystyrene elastomer resin of the component (B), a commercially available product can be appropriately selected and used as long as the acid value is 10 mgKOH / g or less. Examples of such commercially available polystyrene elastomer resins include A1535HU (trade name), G1652MU (trade name), G1726VS (trade name), G1645VS (trade name), FG1901GT (trade name), and G1650MU (trade name) manufactured by KRATON. ), G1654HU (trade name), G1730VO (trade name), MD1653MO (trade name) and the like can be preferably used.

[Mixing amount]
The content of the component (B) with respect to 100 parts by weight of the component (A) in the polyimide composition is in the range of 10 parts by weight or more and 100 parts by weight or less, preferably in the range of 20 parts by weight or more and 90 parts by weight or less, and 30 parts by weight. It is more preferably in the range of 80 parts by weight or more and 80 parts by weight or less. If the content of the component (B) with respect to 100 parts by weight of the component (A) is less than 10 parts by weight, the effect of lowering the dielectric loss tangent may not be sufficiently exhibited. On the other hand, when the weight ratio of the component (B) exceeds 100 parts by weight, the adhesiveness when the resin film is formed is lowered, and the solid content concentration in the polyimide composition is too high to increase the viscosity, resulting in handling. Sex may be reduced.

[Arbitrary ingredient]
When the thermoplastic polyimide of the component (A) has a ketone group, it is referred to as an amino compound having the ketone group and at least two primary amino groups as functional groups (in the present specification, "amino compound for cross-linking formation"). A crosslinked structure can be formed by reacting the amino groups (which may be noted) to form a C = N bond. By forming the crosslinked structure, the heat resistance of the thermoplastic polyimide forming the adhesive layer can be improved. Therefore, the polyimide composition of the present embodiment can contain an amino compound for forming a crosslink as an optional component.

A preferred tetracarboxylic acid anhydride for forming a polyimide having a ketone group is, for example, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA), and a diamine compound is, for example, 4 , 4'-Bis (3-aminophenoxy) benzophenone (BABP), 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene (BABB) and other aromatic diamines can be mentioned. For the purpose of forming a crosslinked structure, the polyimide composition of the present embodiment contains BTDA residues derived from BTDA, preferably 50 mol% or more, more preferably 50 mol% or more, particularly with respect to all tetracarboxylic acid residues. It is preferable to contain the thermoplastic polyimide of the component (A) and the amino compound for forming a bridge, which are contained in an amount of 60 mol% or more.

Examples of the crosslink-forming amino compound include (I) a dihydrazide compound, (II) an aromatic diamine, and (III) an aliphatic amine. Among these, the dihydrazide compound is preferable. Aliphatic amines other than dihydrazide compounds tend to form a crosslinked structure even at room temperature, and there is a concern about the storage stability of the varnish, while aromatic diamines need to be heated to a high temperature in order to form a crosslinked structure. As described above, when the dihydrazide compound is used, both the storage stability of the varnish and the shortening of the curing time can be achieved at the same time. Examples of the dihydrazide compound include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutarate dihydrazide, adipic acid dihydrazide, pimelliate dihydrazide, suberic acid dihydrazide, azeline acid dihydrazide, sevacinate dihydrazide, and sebacic acid dihydrazide. Dihydrazide, humalic acid dihydrazide, diglycolic acid dihydrazide, tartrate dihydrazide, apple acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoenyl dihydrazide, 4,4-bisbenzenedihydrazide, 1,4 -Dihydrazide compounds such as naphthoic acid dihydrazide, 2,6-pyridinediacid dihydrazide and itaconic acid dihydrazide are preferred. The above dihydrazide compounds may be used alone or in combination of two or more.

Further, the amino compounds such as (I) dihydrazide compound, (II) aromatic diamine, and (III) aliphatic amine are, for example, a combination of (I) and (II), a combination of (I) and (III), and the like. It is also possible to use two or more kinds in combination across categories, such as the combination of (I), (II) and (III).

Further, from the viewpoint of making the network-like structure formed by cross-linking with the cross-linking amino compound more dense, the cross-linking amino compound used in the present invention has a molecular weight (when the cross-linking amino compound is an oligomer). The weight average molecular weight) is preferably 5,000 or less, more preferably 90 to 2,000, still more preferably 100 to 1,500. Among these, an amino compound for forming a crosslink having a molecular weight of 100 to 1,000 is particularly preferable. When the molecular weight of the cross-linking amino compound is less than 90, one amino group of the cross-linking amino compound only forms a C = N bond with the ketone group of the polyimide resin, and the periphery of the remaining amino groups is sterically formed. Due to the bulkiness, the remaining amino groups tend to be difficult to form a C = N bond.

In the case of cross-linking the ketone group in the thermoplastic polyimide of the component (A) and the amino compound for cross-linking, the amino compound for cross-linking is added to the resin solution containing the component (A) in the thermoplastic polyimide. The ketone group of No. 1 and the primary amino group of the amino compound for forming a crosslink are subjected to a condensation reaction. By this condensation reaction, the resin solution is cured to become a cured product. In this case, the amount of the amino compound for forming a bridge is 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, in total for the primary amino group with respect to 1 mol of the ketone group. It can be more preferably 0.03 mol to 0.9 mol, and most preferably 0.04 mol to 0.6 mol. If the amount of the cross-linking amino compound added so that the total number of primary amino groups is less than 0.004 mol per 1 mol of ketone group, the cross-linking by the cross-linking amino compound is not sufficient, so that after curing, the cross-linking is not sufficient. When the amount of the cross-linking amino compound added exceeds 1.5 mol, the unreacted cross-linking amino compound acts as a thermoplastic and the heat resistance of the adhesive layer is lowered. Tend to let.

The conditions for the condensation reaction for cross-linking are that the ketone group in the thermoplastic polyimide of component (A) reacts with the primary amino group of the cross-linking amino compound to form an imine bond (C = N bond). If it is a condition, it is not particularly limited. The temperature of the heat condensation is to release the water generated by the condensation to the outside of the system, or to simplify the condensation step when the heat condensation reaction is subsequently performed after the synthesis of the thermoplastic polyimide of the component (A). For this reason, for example, the range of 120 to 220 ° C. is preferable, and the range of 140 to 200 ° C. is more preferable. The reaction time is preferably about 30 minutes to 24 hours. The end point of the reaction is the absorption derived from the ketone group in the polyimide resin near 1670 cm ^-1 by measuring the infrared absorption spectrum using, for example, a Fourier transform infrared spectrophotometer (commercially available product: FT / IR620 manufactured by Nippon Spectroscopy). It can be confirmed by the decrease or disappearance of the peak and the appearance of the absorption peak derived from the imine group near 1635 cm ^-1 .

The heat condensation between the ketone group of the thermoplastic polyimide of the component (A) and the primary amino group of the amino compound for forming a crosslink is, for example,
(1) A method of adding and heating an amino compound for forming a crosslink, following the synthesis (imidization) of the thermoplastic polyimide of the component (A).
(2) An excess amount of an amino compound is charged in advance as a diamine component, and following the synthesis (imidization) of the thermoplastic polyimide of the component (A), the remaining amino compounds that are not involved in imidization or amidization are used for cross-linking formation. A method of using it as an amino compound and heating it with a thermoplastic polyimide, or
(3) A method of heating a polyimide composition to which an amino compound for forming a crosslink is added after processing it into a predetermined shape (for example, after applying it to an arbitrary substrate or forming it into a film).
It can be done by such as.

In order to impart heat resistance to the thermoplastic polyimide of the component (A), the formation of an imine bond was described by forming a crosslinked structure, but the present invention is not limited to this, and as a method for curing the thermoplastic polyimide of the component (A). For example, it is also possible to blend and cure a compound having an unsaturated bond such as an epoxy resin, an epoxy resin curing agent, a maleimide, an activated ester resin, or a resin having a styrene skeleton.

In the polyimide composition of the present embodiment, if necessary, as an optional component, an inorganic filler, an organic filler, a plasticizer, a curing accelerator, a coupling agent, a pigment, and a flame retardant, as long as the effects of the invention are not impaired. Etc. can be appropriately blended. Here, examples of the inorganic filler include silicon dioxide, aluminum oxide, beryllium oxide, niobium oxide, titanium oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, magnesium fluoride, and silica. Examples thereof include potassium oxide and metal phosphinic acid salts. These can be used alone or in admixture of two or more. Further, as an optional component, another resin component such as an epoxy resin, a fluororesin, or an olefin resin may be blended.

Further, the polyimide composition of the present embodiment can contain a solvent such as an organic solvent. The thermoplastic polyimide of the component (A) is solvent-soluble, and the polystyrene elastomer resin of the component (B) also exhibits good solubility in aromatic hydrocarbon-based solvents such as xylene and toluene. , The polyimide composition of the present embodiment can be prepared as a polyimide solution (wanice) containing a solvent. Examples of the organic solvent include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone and dimethyl. One or more selected from sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactum, dimethylformamide, cyclohexanone, dioxane, tetrahydrofuran, diglime, triglime, cresol, etc., and the above aromatic hydrocarbon solvent. It is preferable to use a mixed solvent in which the above is mixed at an arbitrary ratio.
The content of the solvent is not particularly limited, but it is preferable to adjust the content so that the concentration of the polyamic acid or the polyimide is about 5 to 30% by weight.

[viscosity]
The viscosity of the polyimide composition is preferably in the range of, for example, 3000 cps to 100,000 cps as the viscosity range in which the handleability when the polyimide composition is applied is improved and a coating film having a uniform thickness is easily formed. It is more preferably within the range of 50,000 cps. If it is out of the above viscosity range, defects such as thickness unevenness and streaks are likely to occur in the film during coating work by a coater or the like.

[Preparation of polyimide composition]
The polyimide composition can be prepared, for example, by blending a polystyrene elastomer resin with a resin solution of a thermoplastic polyimide prepared by using an arbitrary solvent and mixing them. At this time, in order to uniformly mix the thermoplastic polyimide and the polystyrene elastomer resin, the polystyrene elastomer resin may be mixed in a state of being dissolved in a solvent, or a solvent showing high solubility in the polystyrene elastomer resin is added. You may.

The polyimide composition of the present embodiment has excellent flexibility and thermoplasticity when an adhesive layer is formed by using the polyimide composition. Therefore, for example, in FPCs, rigid flex circuit boards, etc., it has preferable properties for applications such as an adhesive layer material and an adhesive for a coverlay film that protects a wiring portion.

[Resin film]
The resin film of the present embodiment is a resin film composed of a single layer or a plurality of layers including a thermoplastic resin layer, and the thermoplastic resin layer mainly contains the solid content (remaining portion excluding the solvent) of the polyimide composition. It is made into a film as an ingredient. That is, the thermoplastic resin layer has the component (A) and the component (B);
(A) Thermoplastic polyimide,
And (B) a polystyrene elastomer resin having an acid value of 10 mgKOH / g or less,
The content of the component (B) with respect to 100 parts by weight of the component (A) is within the range of 10 parts by weight or more and 100 parts by weight or less. The resin film of the present embodiment has excellent high frequency characteristics and excellent adhesiveness (particularly peel strength).

The resin film of the present embodiment is not particularly limited as long as it is an insulating resin film containing the above-mentioned thermoplastic resin layer, and may be a film (sheet) made of only an insulating resin, such as a copper foil. It may be an insulating resin film laminated on a base material such as a resin sheet such as a glass plate, a polyimide film, a polyamide film, or a polyester film.

(Relative permittivity)
The resin film of the present embodiment is provided under constant temperature and humidity conditions of 23 ° C. and 50% RH in order to ensure impedance matching when used for a circuit board such as an FPC and to reduce electrical signal loss. The relative dielectric constant (ε) at 10 GHz after humidity control for 24 hours is preferably 3.3 or less, and more preferably 3.1 or less. If this relative permittivity exceeds 3.3, inconveniences such as loss of electrical signals are likely to occur on the transmission path of high-frequency signals when used for circuit boards such as FPCs.

(Dissipation factor)
Further, the resin film of the present embodiment is subjected to humidity control for 24 hours under constant temperature and humidity conditions of 23 ° C. and 50% RH in order to reduce the loss of electric signals when used for a circuit board such as an FPC. The dielectric loss tangent (Tanδ) at 10 GHz is preferably 0.0020 or less, more preferably 0.0018 or less. If this dielectric loss tangent exceeds 0.0020, inconveniences such as loss of electrical signals are likely to occur on the transmission path of high-frequency signals when used for circuit boards such as FPCs.

(Glass-transition temperature)
The resin film of the present embodiment preferably has a glass transition temperature (Tg) of 250 ° C. or lower, and more preferably 40 ° C. or higher and 200 ° C. or lower. When the Tg of the resin film is 250 ° C. or lower, thermocompression bonding at a low temperature becomes possible, so that the internal stress generated during laminating can be alleviated and the dimensional change after circuit processing can be suppressed. If the Tg of the resin film exceeds 250 ° C., the bonding temperature becomes high, which may impair the dimensional stability after circuit processing.

(Thickness)
The thickness of the resin film of the present embodiment is preferably in the range of, for example, 5 μm or more and 125 μm or less, and more preferably in the range of 8 μm or more and 100 μm or less. If the thickness of the resin film is less than 5 μm, problems such as wrinkles may occur during transportation in the production of the resin film, while if the thickness of the resin film exceeds 125 μm, the productivity of the resin film may decrease. There is.

(Tension modulus)
The resin film of the present embodiment preferably has a tensile elastic modulus in the range of 0.1 GPa to 3.0 GPa from the viewpoints of reducing wrinkles, preventing air bubbles from being caught during laminating, and handling properties. The range of 0.2 GPa to 2.0 GPa is more preferable.

(Maximum elongation)
The resin film of the present embodiment preferably has a maximum elongation in the range of 30% to 200%, preferably 60% to 160, from the viewpoint of bendability and crack prevention when applied as an insulating resin layer of FPC. The range of% is more preferable.

Since the resin film of the present embodiment has low dielectric adjacency and excellent adhesiveness, the adhesive layer in the coverlay film, the circuit board, the multilayer circuit board, the adhesive layer in the copper foil with resin, and the bond ply. It is useful as a bonding sheet or the like.

[Laminate]
The laminate according to the embodiment of the present invention has a base material and an adhesive layer laminated on at least one surface of the base material, and the adhesive layer is made of the above resin film. .. The laminated body may include any layer other than the above. Examples of the base material in the laminate include a base material of an inorganic material such as a copper foil and a glass plate, and a base material of a resin material such as a polyimide film, a polyamide film, and a polyester film.
Preferred embodiments of the laminate include a coverlay film, a copper foil with a resin, and the like.

[Coverlay film]
The coverlay film, which is one aspect of the laminated body, has a coverlay film material layer as a base material and an adhesive layer laminated on one side of the coverlay film material layer, and is an adhesive layer. Is made of the above resin film. The coverlay film may contain any layer other than the above.

The material of the coverlay film material layer is not particularly limited, and for example, a polyimide-based film such as a polyimide resin, a polyetherimide resin, or a polyamide-imide resin, a polyamide-based film, or a polyester-based film can be used. Among these, it is preferable to use a polyimide film having excellent heat resistance. Further, the coverlay film material may contain a black pigment in order to effectively exhibit light-shielding property, concealing property, design property, etc., and the surface of the film material may contain a black pigment as long as the effect of improving the dielectric property is not impaired. It can contain any component such as a matte pigment that suppresses gloss.

The thickness of the coverlay film material layer is not particularly limited, but is preferably in the range of, for example, 5 μm or more and 100 μm or less.
The thickness of the adhesive layer is not particularly limited, but is preferably in the range of, for example, 10 μm or more and 75 μm or less.

The coverlay film of the present embodiment can be manufactured by the method exemplified below.
First, as a first method, a varnish-like polyimide composition containing a solvent is applied to one side of a film material layer for a coverlay, and then dried at a temperature of, for example, 80 to 180 ° C. to form an adhesive layer. By doing so, it is possible to form a coverlay film having a coverlay film material layer and an adhesive layer.

Further, as a second method, a varnish-like polyimide composition containing a solvent is applied onto an arbitrary substrate, dried at a temperature of, for example, 80 to 180 ° C., and then peeled off for an adhesive layer. The coverlay film can be formed by forming the resin film of the above and heat-bonding the resin film to the film material layer for the coverlay at a temperature of, for example, 60 to 220 ° C.

[Copper foil with resin]
A copper foil with a resin, which is another aspect of the laminated body, is obtained by laminating an adhesive layer on at least one side of a copper foil as a base material, and the adhesive layer is made of the above resin film. The copper foil with resin of the present embodiment may contain any layer other than the above.

The thickness of the adhesive layer in the resin-attached copper foil is preferably in the range of, for example, 2 to 125 μm, and more preferably in the range of 2 to 100 μm. If the thickness of the adhesive layer does not reach the above lower limit, there may be a problem that sufficient adhesiveness cannot be guaranteed. On the other hand, if the thickness of the adhesive layer exceeds the above upper limit value, problems such as deterioration of dimensional stability occur. Further, from the viewpoint of low dielectric constant and low dielectric loss tangent, the thickness of the adhesive layer is preferably 3 μm or more.

The material of the copper foil in the copper foil with resin is preferably one containing copper or a copper alloy as a main component. The thickness of the copper foil is preferably 35 μm or less, more preferably in the range of 5 to 25 μm. From the viewpoint of production stability and handleability, the lower limit of the thickness of the copper foil is preferably 5 μm. The copper foil may be rolled copper foil or electrolytic copper foil. Further, as the copper foil, a commercially available copper foil can be used.

The copper foil with resin may be prepared, for example, by sputtering a metal on a resin film to form a seed layer and then forming a copper layer by, for example, copper plating, or heat the resin film and the copper foil. It may be prepared by laminating by a method such as crimping. Further, in order to form an adhesive layer on the copper foil, the copper foil with resin may be prepared by casting a coating liquid of the polyimide composition, drying it to form a coating film, and then performing the necessary heat treatment. good.

[Metal-clad laminate]
(First aspect)
The metal-clad laminate according to the embodiment of the present invention includes an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, and at least one layer of the insulating resin layer is described above. It is made of a resin film. The metal-clad laminate of the present embodiment may include any layer other than the above.

(Second aspect)
The metal-clad laminate according to another embodiment of the present invention is, for example, an insulating resin layer, an adhesive layer laminated on at least one surface of the insulating resin layer, and an insulating resin layer via the adhesive layer. It is a so-called three-layer metal-clad laminate provided with a laminated metal layer, and the adhesive layer is made of the above resin film. The three-layer metal-clad laminate may include any layer other than the above. In the three-layer metal-clad laminate, the adhesive layer may be provided on one or both sides of the insulating resin layer, and the metal layer may be provided on one or both sides of the insulating resin layer via the adhesive layer. Just do it. That is, the three-layer metal-clad laminate may be a single-sided metal-clad laminate or a double-sided metal-clad laminate. A single-sided FPC or a double-sided FPC can be manufactured by processing a wiring circuit by etching a metal layer of a three-layer metal-clad laminate.

The insulating resin layer in the three-layer metal-clad laminate is not particularly limited as long as it is composed of a resin having electrical insulating properties, and is, for example, polyimide, epoxy resin, phenol resin, polyethylene, polypropylene, polytetrafluoroethylene. , Silicone, ETFE and the like, but it is preferably composed of polyimide. The polyimide layer constituting the insulating resin layer may be a single layer or a plurality of layers, but preferably includes a non-thermoplastic polyimide layer.

The thickness of the insulating resin layer in the three-layer metal-clad laminate is preferably in the range of, for example, 1 to 125 μm, and more preferably in the range of 5 to 100 μm. If the thickness of the insulating resin layer does not reach the above lower limit, there may be a problem that sufficient electrical insulation cannot be guaranteed. On the other hand, if the thickness of the insulating resin layer exceeds the above upper limit value, problems such as warpage of the metal-clad laminated board are likely to occur.

The thickness of the adhesive layer in the three-layer metal-clad laminate is preferably in the range of, for example, 0.1 to 125 μm, and more preferably in the range of 0.3 to 100 μm. In the three-layer metal-clad laminate of the present embodiment, if the thickness of the adhesive layer does not reach the above lower limit value, there may be a problem that sufficient adhesiveness cannot be guaranteed. On the other hand, if the thickness of the adhesive layer exceeds the above upper limit value, problems such as deterioration of dimensional stability occur. Further, from the viewpoint of reducing the dielectric constant and the low dielectric loss tangent of the entire insulating layer, which is a laminate of the insulating resin layer and the adhesive layer, the thickness of the adhesive layer is preferably 3 μm or more.
The ratio of the thickness of the insulating resin layer to the thickness of the adhesive layer (thickness of the insulating resin layer / thickness of the adhesive layer) is preferably in the range of, for example, 0.1 to 3.0, and is preferably 0.15 to 2. The range of 0.0 is more preferable. By setting such a ratio, it is possible to suppress the warp of the three-layer metal-clad laminate. Further, the insulating resin layer may contain a filler, if necessary. Examples of the filler include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, metal salts of organic phosphinic acid and the like. These can be used alone or in admixture of two or more.

[Circuit board]
The circuit board according to the embodiment of the present invention is formed by wiring the metal layer of the metal-clad laminate according to any one of the above embodiments. A circuit board such as an FPC can be manufactured by processing one or more metal layers of a metal-clad laminate into a pattern by a conventional method to form a wiring layer (conductor circuit layer). The circuit board may include a coverlay film that covers the wiring layer.

Examples are shown below, and the features of the present invention will be described more specifically. However, the scope of the present invention is not limited to the examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Measurement of Weight Average Molecular Weight (Mw) of Polyimide]
The weight average molecular weight was measured by a gel permeation chromatograph (manufactured by Tosoh Corporation, trade name; HLC-8220GPC was used). Polystyrene was used as a standard substance, and tetrahydrofuran (THF) was used as a developing solvent.

[Measurement of storage elastic modulus]
The measurement was performed using a dynamic viscoelasticity measuring device (DMA: manufactured by TA Instruments, trade name: RSA-G2).

[Evaluation of dielectric properties]
Using a vector network analyzer (manufactured by Agilent, trade name; vector network analyzer E8633C) and an SPDR resonator, the polyimide film (cured polyimide film) is heated under the conditions of temperature; 23 ° C., humidity; 50% RH for 24 hours. After being left to stand, the relative permittivity (ε) and the dielectric positive tangent (Tanδ) at a frequency of 10 GHz were measured.

[Glass transition temperature (Tg)]
The adhesive sheet pressed under the conditions of temperature: 160 ° C., pressure: 3.5 MPa, time: 60 minutes was cut into a test piece having a size of 5 mm × 20 mm, and a dynamic viscoelastic modulus measuring device (DMA: TA Instrument) was cut out. Using RSA-G2) manufactured by Ment, measurement was performed from 30 ° C to 200 ° C at a temperature rise rate of 4 ° C / min and a frequency of 11 Hz, and the temperature at which the elastic modulus change (tan δ) was maximized was transferred to glass. The temperature was set.

[Tension modulus and maximum elongation]
Using a tension tester (Tensilon manufactured by Orientech), a tensile test of 50 mm / min was performed on a test piece (width; 12.7 mm, length; 127 mm) of a resin film, and a tensile elastic modulus and maximum elongation at 25 ° C. Asked.

[Solder heat resistance test (drying)]
Etching and removing one of the copper foils of the double-sided copper-clad laminate (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name; Espanex MB12-25-12UEG), and the other copper foil surface and the adhesive sheet with copper foil. They were laminated in a sandwiched manner and pressed under the conditions of temperature; 160 ° C., pressure; 3.5 MPa, time; 60 minutes. After drying this test piece with copper foil at 135 ° C./60 minutes, it was immersed in a solder bath set at each evaluation temperature from 260 ° C. to 300 ° C. in increments of 260 ° C. for 10 seconds, and the adhesive state was observed. It was confirmed that there were no problems such as foaming, blistering, and peeling. As a judgment, if no defect was found at 280 ° C, it was evaluated as 〇 (good), and if a defect was observed, it was evaluated as × (defective).

[Solder heat resistance test (moisture absorption)]
The copper foil on one side of the double-sided copper-clad laminate (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name; Espanex MB12-25-12UEG) is removed by etching, and the other copper foil surface and the adhesive sheet are removed with copper foil. They were laminated in a sandwiched manner and pressed under the conditions of temperature; 160 ° C., pressure; 3.5 MPa, time; 60 minutes. The test piece with the copper foil was left at 40 ° C. and relative humidity; 90% RH for 72 hours, and then immersed in a solder bath set at each evaluation temperature from 240 ° C. to 10 ° C. in increments of 10 ° C. for 10 seconds. By observing the adhesive state, it was confirmed whether there were any problems such as foaming, blistering, and peeling. As a judgment, if no defect was found at 260 ° C., it was evaluated as 〇 (good), and if a defect was found, it was evaluated as × (defective).

[Measurement of peel strength]
Double-sided copper-clad laminate (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name; Espanex MB12-25-12UEG) was cut into a width of 50 mm and a length of 100 mm, and then the copper foil on one side was removed by etching. An adhesive sheet is placed on the foil side, and a polyimide film (manufactured by Toray DuPont Co., Ltd., trade name; Kapton 50EN-S) is further laminated on this adhesive sheet, and the temperature; 160 ° C., pressure; 3.5 MPa, The laminate was prepared by pressing under the condition of time; 60 minutes. This laminated body is cut out to a width of 5 mm and used as a test piece, and is adhered when the test piece is pulled in the 180 ° direction at a speed of 50 mm / min using a tensile tester (manufactured by Toyo Seiki Seisakusho, trade name; Strograph VE). The peel strength between the agent layer and the copper foil was measured and used as the peel strength.

[Evaluation method of film retention]
The adhesive sheet was cut into test pieces having a width of 20 mm and a length of 20 mm, bent so as to have creases along the diagonal line, and then opened to observe the state of the film. At this time, those with no cracks in the test piece even after making creases and opening were rated as "good", and those with some cracks were rated as "impossible".

[Evaluation method for film defects]
A polyimide varnish was applied to one side of the release-treated PET film, dried at 100 ° C. for 5 minutes, and then dried at 120 ° C. for 10 minutes, and the state of the peeled film was observed. At this time, those having no faintness (dragging marks) due to agglomerates or poor solubility of the elastomer resin were rated as "good", and those with faintness were rated as "impossible".

[Acid value]
The acid value is the number of mg of potassium hydroxide (KOH) required to neutralize 1 g of the sample. This is measured, for example, by the following method. First, weigh the sample precisely, put it in a 250 mL flask, add 50 mL of ethanol or an equal volume mixture of ethanol and ether, heat to dissolve, and if necessary, titrate with 0.1N potassium hydroxide solution while shaking (shaking). Indicator: Phenolphthalein). The end point of the titration is the point where the pink color of the liquid lasts for 30 seconds. Then, a blank test is performed in the same manner for correction, and the acid value value is obtained from the following formula.
Acid value = [Consumption of 0.1N potassium hydroxide solution (mL) x 5.611] / [Sample amount (g)]

The abbreviations used in this example indicate the following compounds.
BTDA: 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride DDA: manufactured by Croda Japan Co., Ltd., trade name: PRIAMINE 1075 distilled and purified (a component; 99.2% by weight, b component: 0 %, C component; 0.8%, amine value: 210 mg KOH / g)
N-12: Dihydrazide dodecanedioate NMP: N-methyl-2-pyrrolidone elastomer resin 1: KRATON, trade name; A1535HU (hydrogenated polystyrene elastomer resin, styrene unit content: 58% by weight, specific gravity; 0.96, No acid value)
Elastomer resin 2: Made by KRATON, trade name; G1652MU (hydrogenated polystyrene elastomer resin, styrene unit content ratio 30% by weight, specific gravity; 0.91, no acid value)
Elastomer resin 3: Made by KRATON, trade name; G1726VS (hydrogenated polystyrene elastomer resin, styrene unit content ratio 30% by weight, specific gravity; 0.91, no acid value)
Elastomer resin 4: KRATON, trade name; G1645VS (hydrogenated polystyrene elastomer resin, styrene unit content 13% by weight, specific gravity; 0.89, no acid value)
Elastomer resin 5: manufactured by KRATON, trade name; FG1901GT (hydrogenated polystyrene elastomer resin, styrene unit content ratio 30% by weight, specific gravity; 0.91, acid value 10 mgKOH / g)
Elastomer resin 6: Manufactured by Asahi Kasei Corporation, trade name; Tuftec M1913 (hydrogenated polystyrene elastomer resin, styrene unit content ratio 30% by weight, specific gravity; 0.91, acid value 11 mgKOH / g)
Elastomer resin 7: manufactured by Asahi Kasei Corporation, trade name; Tuftec M1943 (hydrogenated polystyrene elastomer resin, styrene unit content 20% by weight, specific gravity; 0.91, acid value 11 mgKOH / g)
In the above DDA, "%" of the a component, the b component and the c component means the area percentage of the chromatogram in the GPC measurement. The molecular weight of DDA was calculated by the following formula (1).
Molecular weight = 56.1 x 2 x 1000 / amine value ... (1)

(Synthesis Example 1)
A 1000 ml separable flask is charged with 55.51 g BTDA (0.1721 mol), 94.49 g DDA (0.1735 mol), 210 g NMP and 140 g xylene and mixed well at 40 ° C. for 1 hour. Then, a polyamic acid solution was prepared. This polyamic acid solution was heated to 190 ° C., heated for 10 hours, stirred, and 125 g of xylene was added to complete imidization of polyimide solution 1 (solid content; 31% by weight, weight average molecular weight; 80,900, heat). Plastic polyimide) was prepared.

[Example 1]
1.12 g of N-12 and 7.8 g of the elastomer resin 1 are mixed with 100 g of the polyimide solution 1 prepared in Synthesis Example 1, xylene is added so that the solid content becomes 27% by weight, and the mixture is diluted and stirred. The polyimide varnish 1a was prepared by the above.

[Examples 2 to 8]
Polyimide varnishes 2a to 8a were prepared in the same manner as in Example 1 except that the blending amounts were changed as shown in Table 1 using elastomer resins 1, 2, 3, 4, and 5.

Comparative Examples 1 and 2
Polyimide varnish 9a, the same as in Example 1, except that the blending amounts of the elastomer resins 6 and 7 were changed as shown in Table 1 and the solid content concentration of the polyimide varnish was 31% by weight. 10a was prepared.

Comparative Example 3
A polyimide varnish 11a was prepared in the same manner as in Example 1 except that no elastomer was used and the solid content concentration of the polyimide varnish was 31% by weight.

Tables 1 and 2 show the formulations of Examples 1 to 8 and Comparative Examples 1 to 3.

[Example 9]
The polyimide varnish 1a prepared in Example 1 is applied to one side of a PET film that has been mold-released, dried at 100 ° C. for 5 minutes, dried at 120 ° C. for 10 minutes, and peeled off to obtain an adhesive sheet 1b. (Thickness; 25 μm) was prepared.
The various evaluation results of the adhesive sheet 1b are as follows.
Relative permittivity; 2.5, dielectric loss tangent; 0.0018, tensile elastic modulus; 0.3 GPa, maximum elongation; 136%, Tg; 41 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.5 kN / m, film defect; good

[Example 10]
An adhesive sheet 2b was prepared in the same manner as in Example 9 using the polyimide varnish 2a.
The various evaluation results of the adhesive sheet 2b are as follows.
Relative permittivity; 2.5, dielectric loss tangent; 0.0015, tensile modulus; 0.3 GPa, maximum elongation; 195%, Tg; 43 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.4 kN / m, film defect; good

[Example 11]
An adhesive sheet 3b was prepared in the same manner as in Example 9 using the polyimide varnish 3a.
The various evaluation results of the adhesive sheet 3b are as follows.
Relative permittivity; 2.5, dielectric loss tangent; 0.0013, tensile elastic modulus; 0.3 GPa, maximum elongation; 230%, Tg; 42 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.3 kN / m, film defect; good

[Example 12]
An adhesive sheet 4b was prepared in the same manner as in Example 9 using the polyimide varnish 4a.
The various evaluation results of the adhesive sheet 4b are as follows.
Relative permittivity; 2.6, dielectric loss tangent; 0.0018, tensile modulus; 0.4 GPa, maximum elongation; 118%, Tg; 40 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.5 kN / m, film defect; good

[Example 13]
An adhesive sheet 5b was prepared in the same manner as in Example 9 using the polyimide varnish 5a.
The various evaluation results of the adhesive sheet 5b are as follows.
Relative permittivity; 2.8, dielectric loss tangent; 0.0017, tensile modulus; 0.3 GPa, maximum elongation; 144%, Tg; 40 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.6 kN / m, film defect; good

[Example 14]
An adhesive sheet 6b was prepared in the same manner as in Example 9 using the polyimide varnish 6a.
The various evaluation results of the adhesive sheet 6b are as follows.
Relative permittivity; 2.6, dielectric loss tangent; 0.0018, tensile modulus; 0.3 GPa, maximum elongation; 103%, Tg; 42 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.4 kN / m, film defect; good

[Example 15]
Using the polyimide varnish 7a, the adhesive sheet 7b was prepared in the same manner as in Example 9.
The various evaluation results of the adhesive sheet 7b are as follows.
Relative permittivity; 2.6, dielectric loss tangent; 0.0020, tensile modulus; 0.2 GPa, maximum elongation; 103%, Tg; 41 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.4 kN / m, film defect; good

[Example 16]
An adhesive sheet 8b was prepared in the same manner as in Example 9 using the polyimide varnish 8a.
The various evaluation results of the adhesive sheet 8b are as follows.
Relative permittivity; 2.6, dielectric loss tangent; 0.0019, tensile modulus; 0.3 GPa, maximum elongation; 122%, Tg; 41 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.2 kN / m, film defect; good

Comparative Example 4
An adhesive sheet 9b was prepared in the same manner as in Example 9 using the polyimide varnish 9a.
The various evaluation results of the adhesive sheet 9b are as follows.
Relative permittivity; 2.8, dielectric loss tangent; 0.0022, tensile modulus; 0.3 GPa, maximum elongation; 201%, Tg; 43 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); ×, peel strength; 1.6 kN / m, film defect; not possible

Comparative Example 5
An adhesive sheet 10b was prepared in the same manner as in Example 9 using the polyimide varnish 10a.
The various evaluation results of the adhesive sheet 10b are as follows.
Relative permittivity; 2.8, dielectric loss tangent; 0.0022, tensile modulus; 0.2 GPa, maximum elongation; 185%, Tg; 41 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.4 kN / m, film defect; not possible

Comparative Example 6
An adhesive sheet 11b was prepared in the same manner as in Example 9 using the polyimide varnish 11a.
The various evaluation results of the adhesive sheet 11b are as follows.
Relative permittivity; 2.6, dielectric loss tangent; 0.0021, tensile modulus; 0.5 GPa, maximum elongation; 119%, Tg; 44 ° C., film retention; good, solder heat resistance test (dry); ×, Solder heat resistance test (moisture absorption); ×, peel strength; 1.0 kN / m, film defect; good

The above results are summarized in Table 3.

From Table 3, the adhesive sheets 1b to 8b of Examples 9 to 16 to which the elastomer resin 1 and the elastomer resins 2, 3, 4, and 5 were added were compared with the adhesive sheets 9b and 10b of Comparative Examples 4 and 5. It was confirmed that the dielectric loss tangent was 0.0020 or less, high peel strength was obtained, and there were no film defects. From these results, the adhesive sheet as the resin film according to the present embodiment can be expected to reduce the transmission loss in the high frequency band of, for example, about 10 to 20 GHz, and while maintaining flexibility and film retention. , It was confirmed that it has excellent peel strength.

As described above, as shown in each example, by adding a hydrogenated polystyrene elastomer resin having an acid value of 10 mgKOH / g or less to a polyimide made from an aliphatic diamine, a clear improvement in dielectric properties can be seen, and further peeling is observed. There was also an improvement in strength.
Further, the adhesive sheet obtained in each example may retain its shape as a film by using a hydrogenated polystyrene elastomer resin having an acid value of 10 mgKOH / g or less in a practical range. confirmed.

From the above results, it was confirmed that the resin film according to the present embodiment is suitably used as a material for a circuit board such as a high frequency FPC.

Although the embodiments of the present invention have been described in detail for the purpose of illustration, the present invention is not limited to the above embodiments and can be modified in various ways.

Claims (12)

The following components (A) and (B);
(A) thermoplastic polyimide, and (B) polystyrene elastomer resin having an acid value of 10 mgKOH / g or less.
The polyimide composition containing the above component (A) and having the content of the component (B) in the range of 10 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the component (A). The polyimide composition according to claim 1, wherein the content ratio of the styrene unit in the component (B) is in the range of 10% by weight or more and 65% by weight or less. The thermoplastic polyimide is formed by reacting a tetracarboxylic acid anhydride component with a diamine component, and according to claim 1 or 2, the diamine component contains 40 mol% or more of an aliphatic diamine with respect to the diamine component. Polyimide composition. The third aspect of claim 3, wherein the aliphatic diamine is a dimerdiamine composition containing a dimerdiamine as a main component, wherein the two terminal carboxylic acid groups of the dimer acid are replaced with a primary aminomethyl group or an amino group. Polyimide composition. The polyimide composition according to any one of claims 1 to 4, further comprising an amino compound having at least two primary amino groups as functional groups. A resin film containing a thermoplastic resin layer.
The thermoplastic resin layer has the following components (A) and (B);
(A) thermoplastic polyimide, and (B) polystyrene elastomer resin having an acid value of 10 mgKOH / g or less.
The resin film is characterized in that the content of the component (B) with respect to 100 parts by weight of the component (A) is within the range of 10 parts by weight or more and 100 parts by weight or less. The thermoplastic resin layer has a dielectric loss tangent (Tan δ) of 0. The resin film according to claim 6, which is 0020 or less. A laminate having a substrate and an adhesive layer laminated on at least one surface of the substrate.
A laminate characterized in that the adhesive layer is made of the resin film according to claim 6. A coverlay film having a coverlay film material layer and an adhesive layer laminated on the coverlay film material layer.
A coverlay film, wherein the adhesive layer is made of the resin film according to claim 6. A copper foil with a resin in which an adhesive layer and a copper foil are laminated.
A copper foil with a resin, wherein the adhesive layer is made of the resin film according to claim 6. A metal-clad laminate having an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer.
A metal-clad laminate characterized in that at least one of the insulating resin layers is made of the resin film according to claim 6. A circuit board obtained by wiring the metal layer of the metal-clad laminate according to claim 11.