JP2005088309A - Substrate film with metal foil layer and substrate film with metal foil on both sides - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate film with metal foil which has enough adhesive properties between the metal foil and the substrate film even when metal foil having a smooth surface is used and excellent heat resistance even when the substrate film with metal foil on both sides is formed and is excellent in work properties during production and low in costs. <P>SOLUTION: The substrate film with the metal foil is composed of the metal foil and the substrate film made of the cured product of a curable resin set on the metal foil. The curable resin contains a polyamidimide having a main chain of a siloxane structure and a weight average molecular weight of at least 80,000, an amide-reactive compound, and an inorganic filler which are incorporated in prescribed amounts respectively.Since the cured product of the curable resin is excellent in heat resistance and adhesive properties to a smooth metal surface, the substrate film with the metal foil is high in heat resistance, and the metal foil can hardly be peeled off from the substrate film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a substrate film with metal foil and a substrate film with double-sided metal foil.

  In recent years, as a printed wiring board mounted on a portable electronic device or the like, a flexible printed wiring board having characteristics such as being thin and excellent in flexibility has been widely used. Among them, for the purpose of further improving the wiring density in the printed wiring board, a flexible printed wiring board in which wiring circuits are formed on both surfaces has attracted attention. These flexible printed wiring boards are composed of a resin substrate film and a wiring circuit formed on the surface of the substrate film, and the resin forming the substrate film is excellent in heat resistance, flexibility and mechanical strength. Polyimide is mainly used (for example, refer to Patent Document 1). A flexible printed wiring board having such a configuration uses a substrate film with a metal foil in which a metal foil is laminated on the surface (one side or both sides) of the substrate film, and this metal foil is processed by a known method such as etching. In general, the wiring circuit is manufactured.

  By the way, the characteristic that the metal foil and the board | substrate film are adhere | attached firmly is calculated | required by the board | substrate film with metal foil used in such a manufacturing method. This is because if the adhesive strength between the metal foil and the substrate film is weak, there is a risk that the formed wiring circuit will be peeled off from the substrate film. Therefore, in a conventional substrate film with a metal foil, a metal foil having a fine irregular shape formed on the surface by electrical or chemical roughening treatment is used, and the resin before the formation of the substrate film is made into this irregularity at the time of manufacture. The adhesive force was improved by making it soak and exhibit the anchor effect.

Such a conventional substrate film with a metal foil is manufactured, for example, by the following manufacturing method. That is, (A) a method of forming a polyimide film that is a substrate film by casting a polyamic acid varnish that is a polyimide precursor on the surface of a metal foil, and then imidizing the applied polyamic acid, (B) A method of adhering a preformed polyimide film and a metal foil through an adhesive layer, (C) By modifying the polyimide, properties such as high solvent solubility and heat fusibility are imparted. A method of adhering a polyimide film and a metal foil whose adhesion has been improved by modification, (D) after forming a thin film made of metal on the surface of the polyimide film by a dry process such as sputtering, and further by plating or the like on this thin film A method of forming a metal layer is known.
JP 2003-012924 A

  However, when the conventional substrate film with a metal foil using a metal foil having a roughened surface is used, it is difficult to increase the frequency of a transmission signal in the obtained flexible printed wiring board. This is because the magnetic field lines generated in the vicinity of the current flowing in the wiring interfere with the center of the conductor, and the current concentrates on the surface of the wiring circuit due to this interference (this phenomenon is generally referred to as the “skin effect”). It is caused by. When the surface of the wiring circuit is roughened like the above-described prior art printed wiring board, when current is concentrated on the surface due to the skin effect, the resistance is remarkably increased due to the unevenness. In this case, it is difficult to increase the frequency of the transmission signal, and it is also difficult to increase the operation speed of the electronic device equipped with this flexible printed wiring board.

  Therefore, it is desirable to use a metal foil having a smooth surface from the viewpoint of speeding up the operation. However, when a metal foil having a smooth surface is used, the anchor effect between the polyimide and the metal foil described above becomes difficult to obtain, and the adhesion between the metal foil and the polyimide film is lowered, and the wiring formed thereby becomes a substrate. There is a risk of inconvenience such as peeling from the surface. For this reason, in the conventional substrate film with metal foil, it was difficult to use metal foil with a smooth surface.

  Moreover, there existed some inconveniences shown below in the manufacturing method of the board | substrate film with a metal foil of said (A)-(D). For example, the method (A) is unsuitable for the production of a double-sided metal foil-attached substrate film having metal foils on both sides. This is because the imidization of polyamic acid proceeds by causing a dehydration cyclization reaction under a high temperature condition of 300 ° C. or higher, and water is generated along with the dehydration cyclization reaction. In order to form a substrate film with a double-sided metal foil, it is necessary to imidize the metal foil on a polyamic acid varnish coated on the metal foil. If it is covered, it will be difficult to remove the water generated with imidization. If it becomes like this, the production | generation of the polyimide film which is a board | substrate film will become disadvantageous, and manufacture of a board | substrate film with a double-sided metal foil will become difficult.

  On the other hand, in the method (B), since the preliminarily formed polyimide film and the metal foil are bonded via the adhesive layer, it is possible to easily manufacture the substrate film with double-sided metal foil. it can. However, since the resin constituting the adhesive layer is generally lower in heat resistance than polyimide, the heat resistance of the resulting laminated sheet with metal foil has also been lowered.

  In addition, a laminate with a double-sided metal foil can also be produced by the method (C) described above, and according to such a method, no adhesive layer is required for adhesion between the metal foil and the substrate film. There is no concern of a decrease in heat resistance. However, since the modified polyimide has a lower glass transition temperature than that of the unmodified one, it has still been difficult to obtain a substrate film with metal foil having sufficient heat resistance.

  According to the above method (D), the above-mentioned drawbacks in the methods (A) to (C) are eliminated. However, this method requires a two-step process that requires complicated operations or apparatuses such as sputtering and plating, which increases the manufacturing cost.

  The present invention has been made in view of the above circumstances, and even when a metal foil with a smooth surface is used, the adhesion between the metal foil and the substrate film is sufficient, and the substrate with double-sided metal foil An object is to provide a substrate film with a metal foil which has excellent heat resistance even when a film is formed, and which is excellent in workability and cost during production.

In order to achieve the above object, a substrate film with a metal foil of the present invention is a substrate film with a metal foil comprising a metal foil and a substrate film made of a cured product of a curable resin and provided on the metal foil, The curable resin includes a polyamideimide having a siloxane structure in the main chain and a weight average molecular weight of 80,000 or more, an amide reactive compound having a functional group that reacts with an amide group of the polyamideimide, and the total volume. The content of the amide group in the polyamide-imide (“content of amide group” is hereinafter abbreviated as “amount of amide group”) is Pa weight. %, If the amide-reactive compound contains an amide group, its content is Ea% by weight, and the silicon atom content in the polyamide-imide (“silicon atom content” is hereinafter abbreviated as “silicon content”). ) Is Pc wt%, and when the amide-reactive compound contains a silicon atom, when the content is Ec wt%, the weight part B of the amide-reactive compound with respect to 100 parts by weight of the polyamideimide is represented by the following formula ( It is characterized by satisfying I) and (II).
3 ≦ (Pa × 100 + Ea × B) / (100 + B) ≦ 11 (I)
1 ≦ (Pc × 100 + Ec × B) / (100 + B) ≦ 16 (II)

  Since the curable resin that satisfies the conditions of the above formulas (I) and (II) has extremely high adhesiveness to the metal foil, even if the metal foil has a smooth surface, the curable resin It is strongly bonded to a smooth surface. Therefore, the substrate film formed by curing the curable resin is also firmly bonded to the smooth surface of the metal foil. Moreover, since curable resin which comprises a board | substrate film contains the polyamideimide which has high heat resistance, the board | substrate film with metal foil obtained also comes to have the outstanding heat resistance. Furthermore, since the polyamideimide contained in the curable resin is a polymer having a high degree of polymerization having a molecular weight of 80000 or more, the formed substrate film also has a high mechanical strength.

  Furthermore, since the curing reaction of the curable resin is caused by a reaction between the amide group in the polyamideimide and the functional group that reacts with the amide group of the amide reactive compound, the curable resin is applied onto the metal foil. Then, a substrate film with metal foil can be easily obtained by causing a curing reaction. Also, unlike the case of forming polyimide from a polyimide precursor, water is not generated during the curing reaction, so it is easy to install both sides of a metal foil on both sides of a layer made of a curable resin. A substrate film with a metal foil can be formed.

  Specifically, the polyamideimide as a component constituting the curable resin is a diamine mixture containing an aromatic diamine represented by the following general formula (1) and a siloxane diamine represented by the following general formula (2); Polyamideimide obtained by reacting aromatic diisocyanate with diimidedicarboxylic acid obtained by reacting with trimellitic anhydride is preferable.

［式中、Ｘは下記一般式（３ａ）又は（３ｂ）で表される２価の基、Ｒ^１はアルキル基、フェニル基又は置換フェニル基、Ｒ^２はアルキレン基、フェニレン基又は置換フェニレン基、ｎは１〜１５の整数を示す。

但し、Ｙは、炭素数１〜３の２価の脂肪族炭化水素基、炭素数１〜３の２価のハロゲン化脂肪族炭化水素基、スルホニル基、エーテル基、カルボニル基又は単結合であり、複数存在するＲ^１及びＲ^２のそれぞれは同一であっても異なっていてもよい。］

[Wherein, X is a divalent group represented by the following general formula (3a) or (3b), R ¹ is an alkyl group, a phenyl group or a substituted phenyl group, and R ² is an alkylene group, a phenylene group or a substituted phenylene group. , N represents an integer of 1-15.

Y is a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms, a divalent halogenated aliphatic hydrocarbon group having 1 to 3 carbon atoms, a sulfonyl group, an ether group, a carbonyl group, or a single bond. Each of R ¹ and R ² present in a plurality may be the same or different. ]

  Furthermore, as the amide-reactive compound, a polyfunctional epoxy compound having two or more glycidyl groups is preferable. Since such a polyfunctional epoxy compound has a high reactivity with the amide group of polyamideimide, the reaction between both easily occurs by heating or the like, and the adhesion of the substrate film to the substrate is further improved.

  The substrate film with double-sided metal foil according to the present invention is obtained by sandwiching a substrate film made of a cured product of a curable resin between a first metal foil and a second metal foil, thereby forming the substrate film. The curable resin to be used is preferably the same as the curable resin used for the above-described substrate film with metal foil. Such a substrate film with a double-sided metal foil can be preferably used for the production of a double-sided flexible printed wiring board in which a wiring board is formed on both sides, and the double-sided flexible printed wiring board thus obtained has a substrate and a wiring pattern. It is particularly excellent in properties such as adhesion and heat resistance.

  The substrate film with a double-sided metal foil having such a configuration is obtained by sandwiching a curable resin to be a substrate film by curing between the first metal foil and the second metal foil, and then heating and / or the whole. Or it is preferable in what is obtained by pressurizing.

  Here, as a specific method for sandwiching the curable resin between the first metal foil and the second metal foil, a curable resin to be a substrate film by curing is used as the first metal foil. And the method of making two laminated bodies obtained by laminating | stacking on the one surface of 2nd metal foil contact so that curable resin may oppose can be illustrated.

  Moreover, it is preferable that the metal foil in the board | substrate film with a metal foil of this invention or the board | substrate film with a double-sided metal foil has a 10 point average surface roughness of the adhesion surface with respect to the board | substrate film of 3.0 micrometers or less, respectively. In this way, even if a skin effect occurs in a printed wiring board manufactured using these metal foil-fitted substrate films, the increase in resistance caused thereby is suppressed to the extent that it does not affect the increase in frequency of the transmission signal. .

  The substrate film with metal foil or the substrate film with double-sided metal foil of the present invention is made of the above-mentioned specific polyamideimide, so that even if a smooth metal foil is used on the surface, the substrate film is made of metal. Adhesiveness between the foil and the substrate film is sufficient, heat resistance is excellent, and the manufacturing method is simple. Such a substrate film with a metal foil can be suitably used as a flexible printed wiring board compatible with high-frequency driving by forming a wiring pattern by performing known patterning on the metal foil.

(Substrate film with metal foil)
The board | substrate film with metal foil of this invention is provided with the board | substrate film which consists of metal foil and the hardened | cured material of curable resin provided on this metal foil as mentioned above. Moreover, the board | substrate film with a double-sided metal foil of this invention has the structure by which the board | substrate film which consists of hardened | cured material of curable resin was pinched | interposed between the 1st and 2nd metal foil.

  The substrate film has a siloxane structure in the main chain and a polyamideimide having a weight average molecular weight of 80000 or more, an amide reactive compound having a functional group that causes a reaction with the amide group of the polyamideimide, and the total volume. It consists of curable resin containing 5-50 volume% inorganic filler with respect to this. In such a curable resin, the amount of amide groups in the polyamideimide is Pa wt%, when the amide reactive compound contains an amide group, the amount of amide groups is Ea wt%, the amount of silicon in the polyamideimide is Pc wt%, When the amide-reactive compound contains a silicon atom, when the silicon content is Ec wt%, the weight part B of the amide-reactive compound with respect to 100 parts by weight of the polyamideimide represents the above formulas (I) and (II). Formulated to satisfy.

  When the curable resin satisfies the above formulas (I) and (II), the content of all amide groups (total amount of amide groups) contained in the polyamideimide and amide reactive compound in the curable resin is 3 to 11% by weight, and the content of all silicon atoms contained in the polyamideimide and amide-reactive compound (total silicon amount) is 1 to 16% by weight. When the curable resin does not satisfy at least one of the above formula (I) or (II) and the total amide group amount and the total silicon amount are out of the above ranges, the resulting heat resistance of the substrate film with metal foil is In addition, the adhesive strength between the metal foil and the substrate film becomes insufficient.

  From the viewpoint of further improving the heat resistance and the adhesive strength, the lower limit of (Pa × 100 + Ea × B) / (100 + B) in the above formula (I) is preferably 6, the upper limit is preferably 9, and the ( The lower limit of Pc × 100 + Ec × B) / (100 + B) is preferably 5, and the upper limit is preferably 12.

  Moreover, when the weight average molecular weight of the polyamideimide contained in the curable resin is less than 80,000, the mechanical strength of the obtained substrate film with metal foil is insufficient for the use of the flexible printed wiring board. From the viewpoint of improving the mechanical strength, the weight average molecular weight of the polyamideimide is preferably 80,000 to 150,000, and more preferably 100,000 to 120,000.

  By applying a curable resin satisfying such conditions to a substrate film with a metal foil as a substrate film having a thickness of preferably 5 μm or less, more preferably 4 μm or less, and even more preferably 3 μm or less, The board | substrate film with metal foil excellent in adhesiveness and heat resistance can be obtained. This is mainly due to the polyamideimide in which the siloxane structure is introduced into the polyamideimide having high heat resistance. The polyamideimide having such a structure not only has high adhesiveness with a metal foil or the like, but the residual organic solvent component contained in the resin is extremely easily 5 wt% at a temperature at which the curable resin is not cured. % Can be reduced to below%. When the amount of the remaining organic solvent in the curable resin is reduced to 5% by weight or less, even if the substrate film is exposed to a high temperature in the subsequent process such as soldering, there is almost no blistering due to volatilization of the organic solvent. Does not occur. For this reason, the obtained board | substrate film with metal foil comes to have high heat resistance. Hereinafter, first, each component of curable resin which can comprise such a substrate film is demonstrated.

(Polyamideimide)
Polyamideimide constituting the curable resin has a siloxane structure, an amide bond and an imide bond in the main chain. Here, the siloxane structure refers to a structure having a —SiO— bond in the structure. The siloxane structure is preferably a structure in which two monovalent organic groups are bonded to a silicon atom.

  For example, the polyamideimide is a diimide obtained by reacting a diamine mixture containing the aromatic diamine represented by the general formula (1) and the siloxane diamine represented by the general formula (2) with trimellitic anhydride. Dicarboxylic acid can be obtained and obtained by reacting the obtained diimide dicarboxylic acid with diisocyanate.

In the aromatic diamine represented by general formula (1), the aliphatic hydrocarbon group having 1 to 3 carbon atoms represented by _{Y, -C (CH 3) 2} - group is preferably represented by, The halogenated aliphatic hydrocarbon group having 1 to 3 carbon atoms is preferably a group represented by —C (CF ₃ ) ₂ —. In the siloxane diamine represented by the general formula (2), R ¹ is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and R ² may be carbon. An alkylene group having 1 to 6 carbon atoms is preferable, and an alkylene group having 1 to 3 carbon atoms is more preferable.

  Examples of such aromatic diamines include 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), bis [4- (3-aminophenoxy) phenyl] sulfone, and bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, bis [4- (4-aminophenoxy) phenyl] methane, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ketone, 1,3-bis (4-aminophenoxy) benzene, 1 , 4-bis (aminophenoxy) benzene.

Especially, as aromatic diamine, it is preferable to use the compound represented by following General formula (4), and it is especially preferable to use BAPP. In the formula, Y is as defined above.

  Moreover, as a siloxane diamine represented by the said General formula (2), it is preferable to use a dimethylsiloxane type | system | group both terminal amine and a dimethyl diphenylsiloxane type | mold terminal diamine. Specifically, dimethylsiloxane-based both terminal amines are amino-modified silicone oils X-22-161AS (amine equivalent 450), X-22-161A (amine equivalent 840), X-22-161B (amine equivalent 1500) ( As described above, commercially available as Shin-Etsu Chemical Co., Ltd., BY16-853 (amine equivalent 650), BY-16-853B (amine equivalent 2200) (above, Toray Dow Corning Silicone). Further, dimethyldiphenylsiloxane-based both terminal diamines are commercially available as X-22-9409 (amine equivalent 680), X-22-1660B (amine equivalent 2260, above, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. These can be used alone or in combination.

  In the production of polyamideimide, first, diimide dicarboxylic acid is obtained by reacting a diamine mixture of aromatic diamine and siloxane diamine as described above with trimellitic anhydride. The diimide dicarboxylic acid thus obtained includes compounds represented by the following general formula (5a) and the following general formula (5b).

In the formula, Z is a residue excluding the amino group of the compound represented by the general formula (1). R ¹ , R ² and n are as defined above.

  In the reaction of a diamine mixture containing aromatic diamine and siloxane diamine with trimellitic anhydride, the number of moles of aromatic diamine is A, the number of moles of siloxane diamine is B, and the number of moles of trimellitic anhydride is C. , (A + B) / C is preferably reacted so as to be 1.0 / 2.0 to 1.0 / 2.2. Here, the mixing ratio A / B of A and B is preferably 99.9 / 0.1 to 0/100, and the mixing ratio is preferably determined according to the amine equivalent of B. For example, when the amine equivalent of siloxane diamine is 400 to 500, A / B is 99.9 / 0.1 to 0/100, and when the amine equivalent is 800 to 1000, A / B is 99.9 / 0.1. When A60 is -60/40 and the amine equivalent is 1500-1600, A / B is preferably 99.9 / 0.1-60 / 40. By making A, B and C within the above ranges, the diimide dicarboxylic acid represented by the general formulas (5a) and (5b) can be more easily generated, and the total amount of amide groups and total silicon in the resulting polyamideimide It becomes easy to provide said formula (I) and (II) about quantity.

  In the formation reaction of diimide dicarboxylic acid, first, a diamine mixture containing aromatic diamine and siloxane diamine and trimellitic anhydride are reacted in an aprotic polar solvent at 50 to 90 ° C., and further azeotroped with water. It is preferable to produce by adding a possible aromatic hydrocarbon and reacting at 120 to 180 ° C. to cause a dehydration cyclization reaction. Examples of the aprotic polar solvent used in the reaction include dimethylacetamide, dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, 4-butyrolactone, sulfolane and the like, and N-methyl-2-pyrrolidone is used. More preferred.

  Examples of aromatic hydrocarbons that can be azeotroped with water include toluene, benzene, xylene, and ethylbenzene, and it is preferable to use toluene. The aromatic hydrocarbon is preferably added at a weight ratio of 0.1 to 0.5 with respect to the aprotic polar solvent. And after completion | finish of a dehydration ring closure reaction, it is preferable to raise the temperature further to about 190 degreeC, and to remove the aromatic hydrocarbon which can azeotrope with water.

In the production of polyamideimide, the diimide dicarboxylic acid thus obtained is then reacted with diisocyanate to obtain polyamideimide. As the diisocyanate used here, a compound represented by the following general formula (6) can be used.

In the formula, E is a divalent organic group having at least one aromatic ring or a divalent aliphatic hydrocarbon group, and is a group represented by —C ₆ H ₄ —CH ₂ —C ₆ H ₄ —. And at least one group selected from the group consisting of a tolylene group, a naphthylene group, a hexamethylene group, a 2,2,4-trimethylhexamethylene group and an isophorone group.

  As the diisocyanate represented by the general formula (6), an aliphatic diisocyanate or an aromatic diisocyanate can be used, but it is preferable to use an aromatic diisocyanate, and it is particularly preferable to use both in combination.

  Examples of aromatic diisocyanates include 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, 2,4-tolylene dimer, and the like. As an example, it is particularly preferable to use MDI. By using MDI as the aromatic diisocyanate, the flexibility of the polyamideimide obtained can be improved, the crystallinity can be reduced, and the film-formability of the polyamideimide can be improved.

  Examples of the aliphatic diisocyanate include hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and isophorone diisocyanate.

  When an aromatic diisocyanate and an aliphatic diisocyanate are used in combination, it is preferable to add an aliphatic diisocyanate to the aromatic diisocyanate in an amount of about 5 to 10 mol%, and the combined use further improves the heat resistance of the resulting polyamideimide. Can be improved.

As a result of the reaction between the diimide dicarboxylic acid mixture and the diisocyanate, for example, a polyamideimide having repeating units represented by the following general formula (7) and the following general formula (8) is obtained. These repeating units may be bonded in blocks or may be bonded randomly. In the formula, Z, E, R ^1, R ² and n are as defined above.

  The reaction between the diimide dicarboxylic acid mixture and the aromatic diisocyanate is desirably carried out after removing the aromatic hydrocarbon azeotropic with water in the preparation of the diimide dicarboxylic acid mixture and then cooling the solution to room temperature. Aromatic diisocyanate is added to the solution thus cooled, the temperature is raised to about 190 ° C., and a reaction is carried out for about 2 hours to obtain a polyamideimide. In such a reaction, the amount of aromatic diisocyanate added is preferably 1.0 to 1.5 equivalents, more preferably 1.1 to 1.3 equivalents, relative to 1 equivalent of the resulting diimide dicarboxylic acid mixture. When the addition amount of the aromatic diisocyanate is less than 1.0 equivalent, the flexibility of the obtained substrate film tends to be lowered, and even when it exceeds 1.5 equivalents, the flexibility of the obtained substrate film is similarly obtained. Tend to decrease.

(Amide reactive compounds)
Next, the amide reactive compound constituting the curable resin will be described. As the amide-reactive compound, a thermosetting resin having a functional group that reacts with an amide group can be used. Such amide-reactive compounds may contain amide groups and / or silicon atoms. Examples of the thermosetting resin include polyfunctional epoxy compounds, polyimide resins, unsaturated polyester resins, polyurethane resins, bismaleimide resins, triazine-bismaleimide resins, phenol resins, and the like, and polyfunctional epoxy compounds are preferable. By using a polyfunctional epoxy compound as the amide-reactive compound, not only the heat resistance of the resulting substrate film but also the mechanical and electrical properties can be improved. As such a polyfunctional epoxy compound, a polyfunctional epoxy compound having two or more epoxy groups is preferable, and a polyfunctional epoxy compound having three or more epoxy groups is more preferable.

  Examples of the polyfunctional epoxy compound having two or more epoxy groups include an epoxy resin obtained by reacting a polyhydric phenol such as bisphenol A, a novolac type phenol resin, or an orthocresol novolac type phenol resin with epichlorohydrin; 1,4-butane Epoxy resin formed by reacting polyhydric alcohol such as diol with epichlorohydrin; polyglycidyl ester formed by reacting polybasic acid such as phthalic acid or hexahydrophthalic acid with epichlorohydrin; amine, amide or heterocyclic nitrogen base N-glycidyl derivative of a compound having a alicyclic epoxy resin and the like.

  Particularly suitable as the polyfunctional epoxy compound, as the polyfunctional epoxy compound having three or more glycidyl groups, ZX-15548-2 (manufactured by Tohto Kasei Co., Ltd.), DER-331L (bisphenol A type epoxy resin manufactured by Dow Chemical Co., Ltd.) YDCN-195 (Cresol novolac type epoxy resin manufactured by Tohto Kasei Co., Ltd.) is commercially available and can be suitably used.

  The compounding amount of the amide reactive compound to be contained in the curable resin is determined so that the amide group or silicon atom in the curable resin has a predetermined content. Specifically, the weight part B of the amide-reactive compound with respect to 100 parts by weight of the polyamide-imide is such that the amount of amide groups in the polyamide-imide is Pa wt%, the amount of amide groups in the amide-reactive compound is Ea wt%, When the amount of silicon is Pc wt% and the amount of silicon in the amide-reactive compound is Ec wt%, it is determined so as to satisfy the above formulas (I) and (II).

  When a polyfunctional epoxy compound is used as the amide-reactive compound, it is preferable to further add a curing agent or a curing accelerator for the polyfunctional epoxy compound in the curable resin. Known curing agents and curing accelerators can be added. For example, as the curing agent, amines such as dicyandiamide, diaminodiphenylmethane, guanylurea; imidazoles; hydroquinone, resorcinol, bisphenol A and their halides, polyfunctional phenols such as novolac-type phenol resin, resole-type phenol resin; Examples thereof include acid anhydrides such as phthalic anhydride, benzophenone tetracarboxylic dianhydride, and methyl hymic acid. Examples of the curing accelerator include imidazoles such as alkyl group-substituted imidazole and benzimidazole.

  When adding a hardening | curing agent, the compounding quantity can be determined according to the epoxy equivalent in a polyfunctional epoxy compound. For example, when an amine compound is added as a curing agent, the compound is blended so that the active hydrogen equivalent of the amine is equal to the epoxy equivalent of the polyfunctional epoxy compound. When the curing agent is a polyfunctional phenol or acid anhydride, the compounding amount is 0.6 to 1.2 equivalent of phenolic hydroxyl group or carboxyl group with respect to 1 equivalent of polyfunctional epoxy compound. It is preferable that On the other hand, when adding a hardening accelerator, it is preferable that the compounding quantity shall be 0.001-10 weight part with respect to 100 weight part of polyfunctional epoxy compounds. When the compounding amount of these curing agents or curing accelerators is less than the above range, the polyfunctional epoxy compound is insufficiently cured and the glass transition temperature after curing of the curable resin tends to decrease. On the other hand, when the amount is larger than the above range, the electrical characteristics after curing of the curable resin tend to be reduced by the remaining curing agent or curing accelerator.

(Inorganic filler)
The curable resin of the present invention further contains an inorganic filler in addition to the above polyamideimide and amide reactive compounds. When an inorganic filler is contained in the curable resin, the coefficient of thermal expansion of the formed substrate film is reduced, and the elastic modulus is improved, whereby the heat resistance and mechanical properties of the obtained substrate film with metal foil are improved. The strength is also extremely good.

  Examples of such inorganic fillers include calcium carbonate, alumina, titanium oxide, mica, aluminum carbonate, aluminum hydroxide, magnesium silicate, aluminum silicate, silica, short glass fiber, aluminum borate whisker, and silicon carbide whisker. And these can be used alone or in combination. Content of these inorganic fillers is 5-50 volume% with respect to the total volume (total volume of solid content of curable resin) of curable resin, and it is preferable in it being 10-50 volume%, and 20-40. More preferably, it is volume%. When content of an inorganic filler is less than 5 volume% or exceeds 50 volume%, it exists in the tendency for the intensity | strength of a board | substrate film to fall or the adhesive strength with the metal foil of a board | substrate film to fall.

  These inorganic fillers are preferably subjected to a predetermined pretreatment for improving dispersibility in the curable resin. Examples of such pretreatment include surface treatment of an inorganic filler with a silicone polymer. In this case, the inorganic filler is blended with the silicone polymer solution, and the mixed solution is mixed with other components of the curable resin (kneading, etc.), so that the surface-treated filler is contained in the curable resin. Can be made. The amount of the silicone polymer used is preferably about 0.01 to 10% by weight, more preferably about 0.05 to 5% by weight, based on the weight of the inorganic filler.

  Examples of the predetermined pretreatment also include a surface treatment of an inorganic filler with a silane coupling agent. In this case as well, as in the case of the silicone polymer, an inorganic filler is blended in the silane coupling agent solution, and this mixed solution is mixed with other components of the curable resin. The amount of the silane coupling agent used is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, based on the weight of the inorganic filler.

  As described above, each component of the curable resin for forming the substrate film has been described. In the curable resin, a filler, a coupling agent, a flame retardant, and the like are further added as other components within a range not inhibiting the curing. You can also.

(Metal foil)
Next, the metal foil used for the substrate film with metal foil will be described. The metal foil is not particularly limited as long as it is made of a metal that is generally used for forming a wiring circuit of a flexible printed wiring board, but a copper foil that is often used as a wiring material is particularly preferable. As the copper foil, an electrolytic copper foil, a rolled copper foil, or the like can be used, and it is preferable that the surface has no irregularities formed by roughening treatment or the like. In order to increase the frequency of a transmission signal when a wiring circuit is formed, a copper foil having a small surface roughness is preferable. Specifically, at least one surface of the copper foil is defined in JIS B0601-1994. The ten-point average surface roughness (Rz) is preferably 3 μm or less, and more preferably Rz is 2 μm. The glossy surface of a normal electrolytic copper foil satisfies these conditions, and when such a copper foil is used, the glossy surface can be used as an adhesive surface to the substrate film as it is.

  Examples of the copper foil satisfying such conditions include F2-WS (Furukawa Circuit Foil, Rz = 3.0) and 3EC-VLP (Mitsui Metals, Rz = 3.0). As a small copper foil, F0-WS (Furukawa Circuit Foil, Rz = 1.2 μm) is commercially available. Further, the thickness of these copper foils is preferably about 9 to 18 μm. In addition, a peelable copper foil in which a release treatment is performed on the surface of the carrier copper foil and an extremely thin copper foil is laminated thereon can be used. In this case, the copper foil having a thickness of 3 μm or 5 μm is used. Can be used. As such copper foil, for example, MTS (manufactured by Mitsui Kinzoku Co., Ltd.), NAP (manufactured by Nippon Electrolytic Co., Ltd.), FCF (manufactured by Furukawa Circuit Foil Co., Ltd.) and the like are commercially available.

  Metal foils other than copper foil include nickel, nickel-phosphorus, nickel between aluminum foil having a thickness of 5 to 200 μm, copper foil layer having a thickness of 0.5 to 15 μm and copper foil layer having a thickness of 10 to 300 μm. -The composite foil of the 3 layer structure which provided the intermediate | middle layer which consists of a tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc., the composite foil of the 2 layer structure which compounded aluminum and copper foil, etc. are mentioned. These metal foils also preferably have a surface roughness that satisfies the above-described conditions.

(Manufacture of substrate film with metal foil)
The substrate film with metal foil of the present invention can be produced by applying a curable resin on the metal foil and then curing the curable resin to obtain a substrate film. Application | coating of curable resin on metal foil can be implemented by a well-known method, Specifically, the method by a comma coater, a dip coater, a kiss coater, natural casting application | coating etc. is mentioned. Such application is preferably performed in a varnish state in which the curable resin is dissolved or dispersed in an organic solvent or the like, and the concentration of the curable resin is 0.1 to 10%, preferably 2 to 6%. In this case, examples of the organic solvent used for the varnish include dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, sulfolane, cyclohexanone, and the like.

  The metal foil with resin in which the curable resin layer is laminated on the metal foil in this manner is heated and / or pressurized under predetermined conditions to cure the curable resin to form a substrate film, and a single-sided metal having a metal foil on one side A substrate film with foil is formed. The heating in this case can be preferably carried out at a temperature of 160 to 250 ° C., and the pressurization can be carried out under a pressure of 0.1 to 8.0 MPa, preferably under vacuum. Heating and pressing are preferably performed simultaneously using a vacuum press or the like, and these treatments are performed for 10 minutes or more, preferably 30 minutes or more, more preferably 60 minutes or more, so that the metal foil and the substrate film can be bonded. The board | substrate film with metal foil excellent in property can be manufactured.

(Substrate film with double-sided metal foil and its manufacture)
Moreover, the curable resin mentioned above can be used suitably also for the board | substrate film with a double-sided metal foil provided with metal foil on both surfaces of the board | substrate film which consists of the hardened | cured material of the said curable resin. Such a substrate film with double-sided metal foil is heated by sandwiching a curable resin to be a substrate film by curing between two metal foils (first metal foil and second metal foil). And what was obtained by the method of pressurizing is preferable. In such a method, for example, a layer made of a curable resin is formed by applying a curable resin on one metal foil, and then a metal foil is further disposed on the curable resin layer. A curable resin can be sandwiched between the foils. In this case, application | coating of curable resin on metal foil can be implemented like the case in the board | substrate film with single-sided metal foil mentioned above. The two metal foils may be the same or different.

  In addition, the curable resin includes two laminates obtained by laminating the curable resin on one side of each of the two metal foils (the first metal foil and the second metal foil). It can also be made to clamp between 1st metal foil and 2nd metal foil by making curable resin contact so that it may oppose. In this case, the curable resin and the metal foil in the two laminates may be the same or different from each other, but at least the curable resin is desirably the same from the viewpoint of adhesion between the laminates.

  When the curable resin is sandwiched between the two metal foils in this way, the curable resin between the metal foils is cured by heating and / or pressing the whole under the same conditions as in the production of the substrate film with a single-sided metal foil. Thus, a substrate film made of a cured product of the curable resin is formed. Thus, a substrate film with double-sided metal foil is obtained.

  The substrate film with double-sided metal foil thus obtained has characteristics that the surface of the metal foil is smooth, and that the adhesion between the substrate film and the metal foil, heat resistance, and flexibility are extremely excellent. A printed wiring board such as a flexible printed wiring board that can operate in a high-frequency region is obtained by forming a wiring pattern by performing known patterning such as etching or plating on the metal foil using the substrate film with double-sided metal foil. Can do.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

[Synthesis of Polyamideimide]
(Synthesis Example 1)
To a 1 L separable flask equipped with a 25 mL water meter with a cock connected to a reflux condenser, a thermometer, and a stirrer, 2,2-bis [4- (4-aminophenoxy) phenyl] as an aromatic diamine 57.5 g (0.14 mol) of propane (BAPP), 50.5 g (0.06 mol) of reactive silicon oil KF8010 (manufactured by Shin-Etsu Chemical Co., Ltd., amine equivalent 421) as siloxane diamine, 80. trimellitic anhydride (TMA) 80. 7 g (0.42 mol) and 462 g of N-methyl-2-pyrrolidone (NMP) as an aprotic polar solvent were charged and stirred at 80 ° C. for 30 minutes.

  After completion of stirring, 100 mL of toluene was added as an aromatic hydrocarbon azeotropic with water, and the temperature was raised to 160 ° C. and refluxed for 2 hours. When it is confirmed that water has accumulated in the moisture determination receiver about 7.2 mL or more and water is no longer distilled, water and toluene in the moisture determination receiver are removed, and the temperature is further increased to 190 ° C. Then, toluene in the reaction solution was removed.

  After returning the solution in the flask to room temperature, 60.1 g (0.24 mol) of 4,4′-diphenylmethane diisocyanate (MDI) was added as an aromatic isocyanate, and the temperature was raised to 190 ° C. and reacted for 2 hours. After the reaction, the solution was cooled to room temperature to obtain an NMP solution of polyamideimide having a weight average molecular weight (MW) of 110,000, an amide group amount of 8.05% by weight, and a silicon amount of 8.68% by weight.

(Synthesis Example 2)
In a 1 L separable flask equipped with a 25 mL water meter with a cock connected to a reflux condenser, a thermometer, and a stirrer, 41.1 g (0.10 mol) of BAPP as an aromatic diamine and reactive as a siloxane diamine 84.2 g (0.10 mol) of silicon oil KF8010, 80.7 g (0.42 mol) of TMA, and 494 g of NMP as an aprotic polar solvent were charged and stirred at 80 ° C. for 30 minutes.

  After completion of stirring, 100 mL of toluene was added as an aromatic hydrocarbon azeotropic with water, and the temperature was raised to 160 ° C. and refluxed for 2 hours. When it is confirmed that water has accumulated in the moisture determination receiver about 7.2 mL or more and water is no longer distilled, water and toluene in the moisture determination receiver are removed, and the temperature is further increased to 190 ° C. Then, toluene in the reaction solution was removed.

  After returning the solution in the flask to room temperature, 60.1 g (0.24 mol) of MDI was added as an aromatic isocyanate, and the temperature was raised to 190 ° C. and reacted for 2 hours. After the reaction, the solution was cooled to room temperature to obtain an NMP solution of polyamideimide having a MW of 105000, an amide group amount of 7.38% by weight, and a silicon amount of 13.26% by weight.

(Synthesis Example 3)
In a 1 L separable flask equipped with a 25 mL water meter with a cock connected to a reflux condenser, a thermometer, and a stirrer, 41.05 g (0.10 mol) of BAPP as an aromatic diamine and reactive as a siloxane diamine Silicon oil X-22-9409 (manufactured by Shin-Etsu Chemical Co., Ltd., amine equivalent 679) 135.8 g (0.10 mol), 80.7 g (0.42 mol) of TMA, 476 g of NMP as an aprotic polar solvent, Stir at 80 ° C. for 30 minutes.

  After completion of stirring, 100 mL of toluene was added as an aromatic hydrocarbon azeotropic with water, and the temperature was raised to 160 ° C. and refluxed for 2 hours. When it is confirmed that water has accumulated in the moisture determination receiver about 7.2 mL or more and water is no longer distilled, water and toluene in the moisture determination receiver are removed, and the temperature is further increased to 190 ° C. Then, toluene in the reaction solution was removed.

  After returning the solution in the flask to room temperature, 60.1 g (0.24 mol) of MDI was added as an aromatic isocyanate, 0.6 g of triethylamine was further added, and the temperature was raised to 130 ° C. and reacted for 4 hours. . After the reaction, the solution was cooled to room temperature to obtain an NMP solution of polyamideimide having a MW of 98,000, an amide group amount of 6.12% by weight, and a silicon amount of 10.99% by weight.

(Comparative Synthesis Example 1)
Reactive silicone oil X-22-161A (made by Shin-Etsu Chemical Co., Ltd., amine) was added as a siloxane diamine to a 1-L separable flask equipped with a 25 mL water meter with a cock connected to a reflux condenser, a thermometer, and a stirrer. Equivalent 805) 161.0 g (0.10 mol), 40.34 g (0.21 mol) of TMA, and 540 g of NMP as an aprotic polar solvent were charged and stirred at 80 ° C. for 30 minutes.

  After completion of stirring, 100 mL of toluene was added as an aromatic hydrocarbon azeotropic with water, and the temperature was raised to 160 ° C. and refluxed for 2 hours. After confirming that about 3.6 mL of water has accumulated in the moisture meter and the water is no longer distilled, remove the water and toluene in the meter and further raise the temperature to 190 ° C. Then, toluene in the reaction solution was removed.

  After returning the solution in the flask to room temperature, 30.1 g (0.12 mol) of MDI was added as an aromatic isocyanate, 1.0 g of triethylamine was further added, and the temperature was raised to 110 ° C. and reacted for 4 hours. . After the reaction, the solution was cooled to room temperature to obtain an NMP solution of polyamideimide having MW 85000, amide group amount 4.07% by weight, and silicon amount 27.96% by weight.

(Comparative Synthesis Example 2)
A 25-mL water quantitative receiver with a cock connected to a reflux condenser, a thermometer, a 1 L separable flask equipped with a stirrer, 57.5 g (0.14 mol) of BAPP as an aromatic diamine, and reactive as a siloxane diamine 50.5 g (0.06 mol) of silicone oil KF8010, 76.8 g (0.40 mol) of TMA, and 548 g of NMP as an aprotic polar solvent were charged and stirred at 80 ° C. for 30 minutes.

  After completion of stirring, 100 mL of toluene was added as an aromatic hydrocarbon azeotropic with water, and the temperature was raised to 160 ° C. and refluxed for 2 hours. After confirming that water has accumulated in the moisture determination receiver about 7.2 mL or more and water is no longer being distilled, remove the water toluene in the moisture determination receiver and further raise the temperature to 190 ° C. The toluene in the reaction solution was removed.

  After returning the solution in the flask to room temperature, 50.1 g (0.20 mol) of MDI was added as an aromatic isocyanate, and the temperature was raised to 190 ° C. and reacted for 2 hours. After the reaction, the solution was cooled to room temperature to obtain an NMP solution of polyamideimide having a MW of 30000, an amide group amount of 8.05% by weight, and a silicon amount of 8.68% by weight.

[Preparation of curable resin for substrate film]
(Filler pretreatment)
In a glass flask equipped with a stirrer, a condenser, and a thermometer, 0.60 g of acetic acid and 17.8 g of distilled water were further added to a solution containing 20 g of dimethoxydimethylsilane, 25 g of tetramethoxysilane, and 105 g of methanol. The mixture was stirred at 0 ° C. for 8 hours to obtain a silicone polymer. The obtained silicone polymer, 700 g of silica filler and 300 g of dimethylacetamide were mixed and stirred at 80 ° C. for 1 hour to obtain a slurry containing silica filler.

(Preparation Example 1)
102.8 g of NMP solution of polyamideimide obtained in Synthesis Example 1 (resin solid content 35% by weight), DER331L which is an epoxy resin as an amide-reactive compound (8.0 g of bisphenol A type epoxy resin manufactured by Dow Chemical Co.) (Dimethylacetamide solution having a resin solid content of 50% by weight) and 0.08 g of 2-ethyl-4-methylimidazole were blended and stirred for about 1 hour until the composition became uniform. Thereafter, 30.8 g of the above-described slurry was put into the solution and mixed for 2 minutes using a rotation / revolution mixer to knead and degas. Further, this solution is filtered through a 200 mesh nylon cloth, and the filtrate is kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide reactive compound is 7.3 wt. %, The total silicon amount was 7.8% by weight, and a curable resin varnish having a silica filler content of 21.2% by volume in the curable resin was obtained.

(Preparation Example 2)
102.8 g of NMP solution of polyamideimide obtained in Synthesis Example 2 (resin solid content 35% by weight), DER331L which is an epoxy resin as an amide-reactive compound (8.0 g of bisphenol A type epoxy resin manufactured by Dow Chemical Company) (Dimethylacetamide solution having a resin solid content of 50% by weight) and 0.08 g of 2-ethyl-4-methylimidazole were blended and stirred for about 1 hour until the composition became uniform. Thereafter, 30.8 g of the above-described slurry was put into the solution and mixed for 2 minutes using a rotation / revolution mixer to knead and degas. Further, this solution is filtered through a 200-mesh nylon cloth, and the filtrate is kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide-reactive compound is 6.6 wt. %, The total silicon amount was 11.9% by weight, and a curable resin varnish having a silica filler content of 21.2% by volume in the curable resin was obtained.

(Preparation Example 3)
7. 90.0 g of NMP solution of polyamideimide obtained in Synthesis Example 3 (resin solid content 40 wt%), YDCN500-10 (Cresol novolac type epoxy resin, manufactured by Tohto Kasei Co., Ltd.) which is an epoxy resin as an amide reactive compound 0 g (dimethylacetamide solution having a resin solid content of 50% by weight) and 0.08 g of 2-ethyl-4-methylimidazole were blended and stirred for about 1 hour until the composition became uniform. Thereafter, 30.8 g of the above-described slurry was put into the solution and mixed for 2 minutes using a rotation / revolution mixer to knead and degas. Further, this solution is filtered with a 200 mesh nylon cloth, and the filtrate is kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide reactive compound is 5.5 wt. %, The total silicon amount was 9.9% by weight, and a curable resin varnish having a silica filler content of 21.2% by volume in the curable resin was obtained.

(Preparation Example 4)
91.4 g of NMP solution of polyamideimide obtained in Synthesis Example 1 (resin solid content 35% by weight), 13000 g of NC3000H (manufactured by Nippon Kayaku Co., Ltd., zylock epoxy resin) as an amide reactive compound ( (Dimethylacetamide solution having a resin solid content of 50% by weight) and 0.16 g of 2-ethyl-4-methylimidazole were blended and stirred for about 1 hour until the composition became uniform. Thereafter, 38.0 g of the above-mentioned slurry was put into the solution, and mixed for 2 minutes using a rotation / revolution mixer to perform kneading and defoaming. Further, this solution is filtered through a 200 mesh nylon cloth, and the filtrate is kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide reactive compound is 7.3 wt. %, The total silicon amount was 7.8% by weight, and a curable resin varnish having a silica filler content of 25% by volume in the curable resin was obtained.

(Preparation Example 5)
108.3 g of NMP solution of polyamideimide obtained in Synthesis Example 1 (resin solid content 35% by weight), 4.0 g of NC3000H which is an epoxy resin as an amide reactive compound (dimethylacetamide solution having a resin solid content of 50% by weight) 2-ethyl-4-methylimidazole (0.16 g) was added and stirred for about 1 hour until the composition became homogeneous. Thereafter, 38.0 g of the above-mentioned slurry was put into the solution, and mixed for 2 minutes using a rotation / revolution mixer to perform kneading and defoaming. Further, this solution was filtered with a 200 mesh nylon cloth, and the filtrate was kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide reactive compound was 7.6 wt. %, The total silicon content was 8.2% by weight, and a curable resin varnish having a silica filler content of 25% by volume in the curable resin was obtained.

(Comparative Preparation Example 1)
90.0 g of NMP solution of polyamideimide obtained in Comparative Synthesis Example 1 (resin solid content 40 wt%), 8.0 g of DER331L epoxy resin as amide reactive compound (dimethylacetamide solution 50 wt% resin solid content) ), 0.08 g of 2-ethyl-4-methylimidazole was blended and stirred for about 1 hour until the composition became homogeneous. Thereafter, 30.8 g of the above-described slurry was put into the solution and mixed for 2 minutes using a rotation / revolution mixer to knead and degas. Further, this solution is filtered with a 200 mesh nylon cloth, and the filtrate is kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide reactive compound is 3.7 wt. %, The total silicon amount was 25.2% by weight, and a varnish of a curable resin having a silica filler content of 21.2% by volume in the curable resin was obtained.

(Comparative Preparation Example 2)
120.0 g of NMP solution of polyamideimide obtained in Comparative Synthesis Example 2 (resin solid content 30% by weight), 8.0 g of DER331L, which is an epoxy resin as an amide reactive compound (dimethylacetamide solution of 50% resin solid content) ), 0.08 g of 2-ethyl-4-methylimidazole was blended and stirred for about 1 hour until the composition became homogeneous. Thereafter, 30.8 g of the above-described slurry was put into the solution and mixed for 2 minutes using a rotation / revolution mixer to knead and degas. Further, this solution was filtered with a 200 mesh nylon cloth, and the filtrate was kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide reactive compound was 7.3 wt. %, The total silicon amount was 7.8% by weight, and a curable resin varnish having a silica filler content of 21.2% by volume in the curable resin was obtained.

(Comparative Preparation Example 3)
59.4 g of NMP solution of polyamideimide obtained in Comparative Synthesis Example 1 (resin solid content 35% by weight), 40.0 g of DER331L epoxide resin as an amide reactive compound (dimethylacetamide solution of 50% resin solid content) ), 0.40 g of 2-ethyl-4-methylimidazole was blended and stirred for about 1 hour until the composition became homogeneous. Thereafter, 35.8 g of the above-mentioned slurry was put into the solution and mixed for 2 minutes using a rotation / revolution mixer to knead and degas. Further, this solution was filtered with a 200 mesh nylon cloth, and the filtrate was kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide reactive compound was 14.0 wt. %, The total silicon content was 2.0% by weight, and a curable resin varnish having a silica filler content of 21.2% by volume in the curable resin was obtained.

(Comparative Preparation Example 4)
102.8 g of NMP solution of polyamideimide obtained in Synthesis Example 1 (resin solid content 35% by weight), 8.0 g of DER331L, which is an epoxy resin as an amide reactive compound (dimethylacetamide solution having a resin solid content of 50% by weight) Then, 0.08 g of 2-ethyl-4-methylimidazole was blended and stirred for about 1 hour until the composition became homogeneous, and then the solution was degassed, and all of the mixture of polyamideimide and amide-reactive compound was mixed. A curable resin varnish having an amide group amount of 7.3% by weight and a total silicon amount of 7.8% by weight was obtained.

(Comparative Preparation Example 5)
102.8 g of NMP solution of polyamideimide obtained in Synthesis Example 1 (resin solid content 35% by weight), 8.0 g of DER331L, which is an epoxy resin as an amide reactive compound (dimethylacetamide solution having a resin solid content of 50% by weight) Then, 0.08 g of 2-ethyl-4-methylimidazole was blended and stirred for about 1 hour until the composition became uniform. Thereafter, 66.7 g of the above-mentioned slurry was put into the solution and mixed for 2 minutes using a rotation / revolution mixer to knead and degas. Further, this solution is filtered through a 200 mesh nylon cloth, and the filtrate is kneaded for 1 minute with a rotation / revolution mixer, so that the total amount of amide groups in the mixture of polyamideimide and amide reactive compound is 7.3 wt. %, The total silicon amount was 7.8% by weight, and a curable resin varnish having a silica filler content of 53.8% by volume in the curable resin was obtained.

[Production of substrate film with metal foil]
(Examples 1-5, Comparative Examples 1-5)
The varnish of the curable resin obtained in Preparation Examples 1 to 5 and Comparative Adjustment Examples 1 to 5, the roughened surface (Rz = 5.0 μm) or the glossy surface (Rz = 1.5 μm) of the electrolytic copper foil (thickness 12 μm). ), Respectively, and dried at 130 ° C. for 20 minutes to obtain a metal foil with resin, and this metal foil with resin was heated at 230 ° C. for 60 minutes to obtain a substrate film with single-sided metal foil. . Also, two metal foils with resin obtained using each varnish were prepared, and the same metal foils with resin were stacked so that the resin side was in contact with each other to form a laminate. Vacuum pressing was performed at 2 MPa for 60 minutes to obtain a substrate film with double-sided copper foil. In addition, the single-sided metal obtained using the curable resin of the comparative preparation examples 1-5 by making the board | substrate film with a single-sided metal foil obtained using the curable resin of the preparation examples 1-5 into Example 1a-5a, respectively. The board | substrate film with foil was made into Comparative Examples 1a-5a. Moreover, let the board | substrate film with a double-sided metal foil obtained using the curable resin of Preparation Examples 1-5 be Examples 1b-5b, and the double-sided metal foil obtained using the curable resin of Comparative Preparation Examples 1-5 The attached substrate film was set as Comparative Examples 1b to 5b.

[Measurement of breaking strength]
In order to measure the breaking strength of the substrate films in the substrate films with metal foils of Examples 1 to 5 and Comparative Examples 1 to 5, the metal foils in the substrate films with single-sided metal foils of Examples 1a to 5a and Comparative Examples 1a to 5a were used. Each substrate film obtained by etching and removing with an aqueous ammonium persulfate solution was dried at 100 ° C. for 20 minutes, then cut into a 10 mm width strip, and Autograph AC100C (Shimadzu Corporation) was obtained using each strip. Tensile test was conducted to determine the breaking strength of each substrate film. The obtained results are shown in Table 1.

[Confirmation of warpage]
The board | substrate film with metal foil of Examples 1a-5a and Comparative Examples 1a-5a was observed visually, and it was evaluated whether the curvature has produced. The results obtained are shown in Table 2, where the substrate film with metal foil in which no occurrence of warpage was observed was marked with ◯, and the substrate film with metal foil in which warpage was observed was marked with x.

[Measurement of adhesive strength]
Peeling strength (90 °) when the copper foils in the substrate films with metal foils of Examples 1a to 5a, Examples 1b to 5b, Comparative Examples 1a to 5a, and Comparative Examples 1b to 5b are each peeled in the direction of 90 degrees. The peel strength, based on JIS C6481) was measured, and the obtained value was defined as the adhesive strength (kN / m) between the copper foil and the substrate film. The adhesive strength was measured for both the substrate film with metal foil in which the roughened surface of the metal foil was bonded to the substrate film and the substrate film with metal foil in which the glossy surface was bonded to the substrate film. The obtained results are shown in Table 2.

[Solder heat resistance test]
What cut | disconnected the board film with metal foil of Example 1a-5a, Example 1b-5b, Comparative example 1a-5a, and Comparative example 1b-5b to 20 mm x 20 mm was used as the sample for a solder heat resistance test, and this sample was used. Each piece is immersed in a 260 ° C solder bath, and the solder heat resistance is evaluated by visually checking whether there is blistering at the adhesive interface between the copper foil and the substrate film or peeling of the copper foil from the substrate film. It was. The solder heat resistance was evaluated by measuring the time (seconds) from when the sample was immersed in the solder bath until blistering or peeling occurred. The obtained results are shown in Table 2.

  From Tables 1 and 2, the substrate films with metal foils of Examples 1 to 5 are all 1.2 kN / m or more for the glossy surface when the substrate film is adhered to the roughened surface of the electrolytic copper foil. Even if they are bonded together, it has been found that the adhesive strength is 0.7 kN / m or more, and the substrate film used in these materials has a breaking strength of 58 MPa or more. Furthermore, in the board | substrate film with metal foil of Examples 1-5, generation | occurrence | production of the curvature was not seen.

  On the other hand, the substrate films with metal foils of Comparative Examples 1 to 3 in which the total amide group amount and the total silicon amount were outside the range of the substrate film with metal foils of the present invention were substrates with respect to the roughened surface of the metal foil. Even if the film was adhered, the adhesive strength was 0.6 kN / m or less.

  Moreover, the board | substrate film with a metal foil of the comparative example 4 which does not contain an inorganic filler in curable resin produced the curvature | sledge with the electrolytic copper foil outside. Furthermore, the substrate film with metal foil of Comparative Example 5 in which the content of the inorganic filler was 50% by volume or more, and the substrate film with metal foil of Comparative Example 2 in which the weight average molecular weight of the polyamideimide was less than 80000, The breaking strength of the substrate film was 15.6 MPa and 12.3 MPa, respectively, and it was found that the substrate film was inferior to the substrate films in other substrate films with metal foil.

Claims (9)

A metal foil and a substrate film comprising a cured product of a curable resin and provided on the metal foil, and a substrate film with a metal foil comprising:
The curable resin includes a polyamideimide having a siloxane structure in the main chain and a weight average molecular weight of 80,000 or more, an amide reactive compound having a functional group that reacts with an amide group of the polyamideimide, and a total volume. 5 to 50% by volume of an inorganic filler, and
The content of amide groups in the polyamideimide is Pa wt%, when the amide reactive compound contains an amide group, the content is Ea wt%, the content of silicon atoms in the polyamideimide is Pc wt%, When the amide reactive compound contains a silicon atom, when the content is Ec wt%,
The weight part B of the amide-reactive compound with respect to 100 parts by weight of the polyamideimide is represented by the following formulas (I) and (II):
3 ≦ (Pa × 100 + Ea × B) / (100 + B) ≦ 11 (I)
1 ≦ (Pc × 100 + Ec × B) / (100 + B) ≦ 16 (II)
The board | substrate film with metal foil characterized by satisfy | filling.   The substrate film with metal foil according to claim 1, wherein the ten-point average surface roughness of the surface of the metal foil facing the substrate film is 3.0 μm or less. The polyamideimide is
Diimide dicarboxylic acid obtained by reacting an aromatic diamine represented by the following general formula (1) and a diamine mixture containing a siloxane diamine represented by the following general formula (2) with trimellitic anhydride,
3. The substrate film with metal foil according to claim 1, which is a polyamideimide obtained by reacting diisocyanate.

[Wherein, X is a divalent group represented by the following general formula (3a) or (3b), R ¹ is an alkyl group, a phenyl group or a substituted phenyl group, and R ² is an alkylene group, a phenylene group or a substituted phenylene group. , N represents an integer of 1-15.

Y is a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms, a divalent halogenated aliphatic hydrocarbon group having 1 to 3 carbon atoms, a sulfonyl group, an ether group, a carbonyl group, or a single bond. Each of R ¹ and R ² present in a plurality may be the same or different. ]   The substrate film with metal foil according to any one of claims 1 to 3, wherein the amide-reactive compound is a polyfunctional epoxy compound having two or more glycidyl groups. A substrate film with a double-sided metal foil formed by sandwiching a substrate film made of a cured product of a curable resin between the first metal foil and the second metal foil,
The curable resin includes a polyamideimide having a siloxane structure in the main chain and a weight average molecular weight of 80,000 or more, an amide reactive compound having a functional group that reacts with an amide group of the polyamideimide, and a total volume. 5 to 50% by volume of an inorganic filler, and
The content of amide groups in the polyamideimide is Pa wt%, when the amide reactive compound contains an amide group, the content is Ea wt%, the content of silicon atoms in the polyamideimide is Pc wt%, When the amide reactive compound contains a silicon atom, when the content is Ec wt%,
The weight part B of the amide-reactive compound with respect to 100 parts by weight of the polyamideimide is represented by the following formulas (I) and (II):
3 ≦ (Pa × 100 + Ea × B) / (100 + B) ≦ 11 (I)
1 ≦ (Pc × 100 + Ec × B) / (100 + B) ≦ 16 (II)
The board | substrate film with a double-sided metal foil characterized by satisfy | filling.   6. The substrate film with double-sided metal foil according to claim 5, wherein the ten-point average surface roughness of the surface of the metal foil facing the substrate film is 3.0 [mu] m or less. A substrate film with a double-sided metal foil obtained by sandwiching a curable resin to be a substrate film by curing between the first metal foil and the second metal foil and heating and / or pressing the whole. And
The curable resin has a siloxane structure in the main chain, and a polyamideimide having a weight average molecular weight of 80000 or more, an amide reactive compound having a functional group that reacts with an amide group of the polyamideimide, and the whole 5 to 50% by volume of inorganic filler with respect to the product, and
The content of amide groups in the polyamideimide is Pa wt%, when the amide reactive compound contains an amide group, the content is Ea wt%, the content of silicon atoms in the polyamideimide is Pc wt%, When the amide reactive compound contains a silicon atom, when the content is Ec wt%,
The weight part B of the amide-reactive compound with respect to 100 parts by weight of the polyamideimide is represented by the following formulas (I) and (II):
3 ≦ (Pa × 100 + Ea × B) / (100 + B) ≦ 11 (I)
1 ≦ (Pc × 100 + Ec × B) / (100 + B) ≦ 16 (II)
The board | substrate film with a double-sided metal foil characterized by satisfy | filling.   Two laminates obtained by laminating a curable resin to be a substrate film by curing on one side of the first metal foil and the second metal foil are contacted so that the curable resin faces each other. 8. A substrate film with a double-sided metal foil according to claim 7, wherein a curable resin to be a substrate film by curing is sandwiched between the first metal foil and the second metal foil. .   The substrate film with double-sided metal foil according to claim 7 or 8, wherein a ten-point average surface roughness of a surface of the metal foil facing the curable resin is 3.0 µm or less.