JP6041204B2 - Base material for manufacturing flexible printed wiring board, flexible printed wiring board, and flex-rigid printed wiring board - Google Patents

Description

  The present invention relates to a substrate for manufacturing a flexible printed wiring board suitable as a material for manufacturing a flexible printed wiring board or a flex-rigid printed wiring board, and a flexible print manufactured using the substrate for manufacturing a flexible printed wiring board. The present invention relates to a wiring board and a flex / rigid printed wiring board.

  Many flexible printed wiring boards and flex-rigid printed wiring boards are used in small and thin electronic devices. In recent years, demands for multi-layered flexible printed wiring boards and flex / rigid printed wiring boards have increased due to demands for higher density and thinness in electronic devices, and requirements for quality have become severe. For multilayering, for example, a bonding sheet, a metal foil with resin, or the like is used (see Patent Documents 1 and 2).

JP 2011-49332 A Japanese Patent Application No. 2005-127101

  With the increase in the number of flexible printed wiring boards and flex-rigid printed wiring boards, via holes are often formed in these printed wiring boards. For this purpose, laser processing is often employed from the viewpoint of fine wiring.

  However, if a hole is formed in the flexible printed wiring board or the flex-rigid printed wiring board by laser processing, a resin residue remains on the inner surface of the hole, or the inner surface becomes rough and irregularities are easily formed. In particular, unevenness is easily formed on the inner surface of the hole by the desmear treatment. As a result, it is difficult to form a uniform plating layer when the inner surface of the hole is plated, and therefore, the conduction stability of the via hole tends to be impaired.

  Therefore, in order to improve laser processability, it is conceivable to include an inorganic filler in the insulating layer of the flexible printed wiring board or the flex-rigid printed wiring board, but in that case, the flexible printed wiring board or the flex-rigid printed wiring board There arises a problem that the flexibility (flexibility) of the glass tends to decrease.

  The present invention has been made in view of the above-mentioned reasons, and an object of the present invention is to provide a flexible printed wiring board or a flex-rigid printed wiring board having excellent laser processability and good flexibility (flexibility). A flexible printed wiring board manufacturing base material used for manufacturing, a flexible printed wiring board manufactured using this flexible printed wiring board manufacturing base material, and a flex-rigid printed wiring board are provided. .

  The substrate for producing a flexible printed wiring board according to the first aspect of the present invention comprises at least one particle-containing resin layer containing silica having an average particle size of 5 to 200 nm and a maximum particle size of 500 nm or less in a range of 2 to 20 phr. Prepare.

  The base material for manufacturing a flexible printed wiring board according to the second aspect of the present invention further comprises a metal foil laminated directly or indirectly on the particle-containing resin layer in the first aspect.

  The substrate for manufacturing a flexible printed wiring board according to the third aspect of the present invention is the first resin layer and the second half-cured state laminated on the first resin layer in the first aspect. A resin layer, and at least one of the first resin layer and the second resin layer is the particle-containing resin layer.

  In the base material for manufacturing a flexible printed wiring board according to the fourth aspect of the present invention, in the third aspect, the first resin layer is formed from a first resin composition containing a polyamideimide resin, The structural unit constituting the polyamideimide resin includes a first structural unit represented by the following structural formula (1) and a second structural unit represented by the following structural formula (2). The ratio of the second structural unit to the total of the unit and the second structural unit is in the range of 5 to 35 mol%.

  In the base material for manufacturing a flexible printed wiring board according to the fifth aspect of the present invention, in the fourth aspect, the first resin composition further contains bismaleimide.

  In the base material for producing a flexible printed wiring board according to the sixth aspect of the present invention, in the fifth aspect, the bismaleimide is 4,4′-diphenylmethane bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3′-. It is at least one selected from dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide and 1,6′-bismaleimide- (2,2,4-trimethyl) hexane.

  In the base material for manufacturing a flexible printed wiring board according to the seventh aspect of the present invention, in the fifth or sixth aspect, the total amount of the polyamideimide resin and the bismaleimide in the first resin composition. The ratio of the bismaleimide is in the range of 3 to 30% by mass.

  In the flexible printed wiring board manufacturing substrate according to the eighth aspect of the present invention, in any one of the third to seventh aspects, the thickness of the first resin layer is in the range of 2 to 15 μm.

  The flexible printed wiring board which concerns on the 9th aspect of this invention is equipped with the insulating layer formed from the said particle | grain containing resin layer in the base material for flexible printed wiring board manufacture concerning a 1st aspect.

  The flexible printed wiring board which concerns on the 10th aspect of this invention is an insulating layer formed from the said particle | grain containing resin layer in the base material for flexible printed wiring board manufacture concerning a 2nd aspect, and the said flexible printed wiring board manufacture A conductor wiring formed from the metal foil in the substrate.

  A flexible printed wiring board according to an eleventh aspect of the present invention is the first resin layer and the second resin layer in the flexible printed wiring board manufacturing base material according to any one of the third to eighth aspects. And a conductive wiring formed from the metal foil in the flexible printed wiring board manufacturing base material.

  The multilayer flexible printed wiring board which concerns on the 12th aspect of this invention is equipped with the insulating layer formed from the said particle | grain containing resin layer in the base material for flexible printed wiring board manufacture concerning a 1st aspect.

  A multilayer flexible printed wiring board according to a thirteenth aspect of the present invention is an insulating layer formed from the particle-containing resin layer in the flexible printed wiring board manufacturing substrate according to the second aspect, and the flexible printed wiring board manufacture. And a conductor wiring formed from the metal foil in the base material 1.

  A multilayer flexible printed wiring board according to a fourteenth aspect of the present invention is the first resin layer and the second resin in the substrate for manufacturing a flexible printed wiring board according to any one of the third to eighth aspects. An insulating layer formed from a layer, and a conductor wiring formed from the metal foil in the substrate for manufacturing the flexible printed wiring board.

  A flex-rigid printed wiring board according to a fifteenth aspect of the present invention is a flex-rigid printed wiring board comprising a plurality of rigid parts and a flex part that connects adjacent rigid parts. The insulating layer formed from the said particle | grain containing resin layer in the base material for flexible printed wiring board manufacture which concerns on this is provided.

  A flex-rigid printed wiring board according to a sixteenth aspect of the present invention is a flex-rigid printed wiring board including a plurality of rigid parts and a flex part that connects adjacent rigid parts, and the second aspect. An insulating layer formed from the particle-containing resin layer in the flexible printed wiring board manufacturing base material according to the present invention and a conductor wiring formed from the metal foil in the flexible printed wiring board manufacturing base material.

  A flex-rigid printed wiring board according to a seventeenth aspect of the present invention is a flex-rigid printed wiring board comprising a plurality of rigid parts and a flex part that connects adjacent rigid parts, In the flexible printed wiring board manufacturing base material according to any one of the aspects 8, the insulating layer formed from the first resin layer and the second resin layer, and the flexible printed wiring board manufacturing base material Conductor wiring formed from the metal foil.

  According to the present invention, a flexible printed wiring board manufacturing base used for manufacturing a flexible printed wiring board or a flex-rigid printed wiring board having excellent laser processability and good flexibility (flexibility). A material can be obtained.

  Moreover, according to this invention, the flexible printed wiring board which is manufactured using the said base material for flexible printed wiring board manufacture, is excellent in laser workability, and has favorable flexibility (flexibility), and a flex. -A rigid printed wiring board can be obtained.

It is sectional drawing which shows the base material (metal foil with resin) for flexible printed wiring board manufacture in 1st embodiment of this invention. It is sectional drawing which shows the base material (metal-clad base material) for flexible printed wiring board manufacture in 2nd embodiment of this invention. It is sectional drawing which shows the base material (bonding sheet) for flexible printed wiring board manufacture in 3rd embodiment of this invention. (a) thru | or (e) are sectional drawings which show the manufacture process of the multilayer flexible printed wiring board in 4th embodiment of this invention. (a) thru | or (e) are sectional drawings which show the manufacture process of the multilayer flexible printed wiring board in the 5th embodiment of this invention. (A) thru | or (c) are sectional drawings which show the manufacturing process of the flex-rigid printed wiring board in the 6th embodiment of this invention.

  The substrate 1 for producing a flexible printed wiring board includes at least one particle-containing resin layer containing silica having an average particle diameter of 5 to 200 nm and a maximum particle diameter of 500 nm or less in a range of 2 to 20 phr. The particle-containing resin layer is composed of, for example, a layer containing a resin in a cured state (C stage state) or a semi-cured state (B stage state) and the silica.

  The average particle diameter of silica is measured by a dynamic light scattering method. As the measuring device, for example, a particle size distribution / particle size distribution measuring device (manufactured by Otsuka Electronics Co., Ltd., model number FPAR-1000) is used. The maximum particle size of silica is measured by a dynamic light scattering method. Also in this case, for example, a particle size distribution / particle size distribution measuring device (manufactured by Otsuka Electronics Co., Ltd., model number FPAR-1000) is used as the measuring device. The silica is not particularly limited, but spherical silica is preferably used. In this case, the packing property of silica in the particle-containing resin layer is improved. The shape of the spherical silica particles is preferably a true sphere, but may not be a true sphere as long as it is considered substantially spherical.

  The particle-containing resin layer in the flexible printed wiring board manufacturing substrate 1 is used for forming an insulating layer in the flexible printed wiring board or the flex printed wiring board. When the insulating layer is formed from the particle-containing resin layer, when the insulating layer is irradiated with laser light for drilling, the thermal conductivity of the insulating layer is improved by the action of silica, so that the resin is formed on the inner surface of the hole. Generation | occurrence | production of a residue, or the inner surface of a hole being rough and uneven | corrugated forming are suppressed. Moreover, even if the desmear process which uses desmear liquids, such as an alkaline permanganate solution, is given to the inner surface of a hole, it is suppressed that an unevenness | corrugation is formed in the inner surface of a hole. For this reason, when the plating process is performed on the inner surface of the hole formed by laser processing, the plating layer is easily formed uniformly, and thus the conduction stability of the via hole is improved. Moreover, the present inventors have found that silica having a particle size as described above hardly inhibits the flexibility of the insulating layer. For this reason, in this embodiment, the favorable laser workability of a flexible printed wiring board or a flex printed wiring board, and the favorable flexible property can be made to make compatible.

  The particle-containing resin layer may further contain an inorganic filler other than silica having the above particle diameter as long as the above action is not inhibited. However, it is particularly preferable that the particle-containing resin layer does not contain an inorganic filler other than silica having the above particle diameter.

  The configuration other than the particle-containing resin layer in the substrate 1 for manufacturing a flexible printed wiring board is not particularly limited as long as it can be used to manufacture a flexible printed wiring board or a flex-rigid printed wiring board.

  For example, the flexible printed wiring board manufacturing substrate 1 may be composed of only one or a plurality of particle-containing resin layers, or one or a plurality of particle-containing resin layers, and a resin layer other than the particle-containing resin layer, You may be comprised from. The substrate 1 for manufacturing a flexible printed wiring board may include a metal foil 2. In this case, the metal foil 2 may be laminated directly or indirectly on the particle-containing resin layer. In addition, the direct means that the metal foil 2 is in direct contact with the particle-containing resin layer, and the indirect means a layer other than the particle-containing resin layer between the metal foil 2 and the particle-containing resin layer. Means intervening. In this case, the particle-containing resin layer can be used to form an insulating layer on the flexible printed wiring board or the flex-rigid printed wiring board. Further, the metal foil 2 can be used for forming a conductor wiring on a flexible printed wiring board or a flex-rigid printed wiring board.

  The substrate 1 for manufacturing a flexible printed wiring board includes a metal foil 2, a first resin layer 3 laminated on the metal foil 2, and a semi-cured first layer laminated on the first resin layer 3. Two resin layers 4 may be provided. That is, the flexible printed wiring board manufacturing substrate 1 may have a structure in which the metal foil 2, the first resin layer 3, and the second resin layer 4 are laminated in this order. In this case, at least one of the first resin layer 3 and the second resin layer 4 is a particle-containing resin layer. In this case, the first resin layer 3 and the second resin layer 4 can be used to form an insulating layer on the flexible printed wiring board or the flex-rigid printed wiring board. Further, the metal foil 2 can be used for forming a conductor wiring on a flexible printed wiring board or a flex-rigid printed wiring board.

  Examples of the substrate 1 for producing a flexible printed wiring board include a metal foil with resin, a metal-clad substrate, and a bonding sheet.

  The base material 1 for flexible printed wiring board manufacture which concerns on 1st embodiment of this invention is shown in FIG. The substrate 1 for manufacturing a flexible printed wiring board in the present embodiment includes a metal foil 2, a first resin layer 3, and a second resin layer 4 in a B-stage state. 11 (metal foil with flexible resin for multilayers).

  In the present embodiment, at least one of the first resin layer 3 and the second resin layer 4 is a particle-containing resin layer. That is, at least one of the first resin layer 3 and the second resin layer 4 contains silica having an average particle size of 5 to 200 nm and a maximum particle size of 500 nm or less in a range of 2 to 20 phr. When the first resin layer 3 is a particle-containing resin layer, when the laser processing is performed on the insulating layer formed from the first resin layer 3 and the second resin layer 4, the first resin layer 3 is formed thereby. Resin residues are less likely to occur on the inner surfaces of the holes. Further, when the second resin layer 4 is a particle-containing resin layer, when the laser processing is applied to the insulating layer formed from the first resin layer 3 and the second resin layer 4, the second resin layer 4 is formed thereby. In particular, the inner surface of the hole is less likely to be rough, and the inner surface is less likely to be uneven. Thereby, the laser processability in the case of performing laser processing on the insulating layer is improved.

  In particular, the first resin layer 3 and the second resin layer 4 are preferably both particle-containing resin layers. That is, the first resin layer 3 contains silica having an average particle size of 5 to 200 nm and a maximum particle size of 500 nm or less in the range of 2 to 20 phr, and the second resin layer 4 has an average particle size of 5 to 200 nm and the maximum particle size. It is preferable to contain silica having a diameter of 500 nm or less in the range of 2 to 20 phr. In this case, when laser processing is performed on the insulating layer formed from the first resin layer 3 and the second resin layer 4, a resin residue is hardly generated on the inner surface of the hole formed thereby. Unevenness is less likely to occur on the inner surface. As a result, the laser processability when the insulating layer is subjected to laser processing is significantly improved.

  There are no particular restrictions on the material of the metal foil 2. An example of the metal foil 2 is a copper foil. Although the thickness of the metal foil 2 is set suitably, it is preferable that it is the range of 1-70 micrometers.

  The first resin layer 3 is preferably formed from a first resin composition containing a polyamideimide resin. Further, when the first resin layer 3 is a particle-containing resin layer, the first resin composition contains silica having an average particle diameter of 5 to 200 nm and a maximum particle diameter of 500 nm or less in a range of 2 to 20 phr. .

  The structural unit (repeating unit) constituting the polyamideimide resin in the first resin composition includes a first structural unit represented by the following structural formula (1) and a second structural unit represented by the following structural formula (2). It is preferable that a structural unit is included.

  The ratio of the second structural unit to the total of the first structural unit and the second structural unit is preferably in the range of 5 to 35 mol%. When the proportion of the second structural unit is 35 mol% or less (that is, the proportion of the first structural unit is 65 mol% or more), the heat resistance of the insulating layer formed from the first resin layer 3 is improved. . In addition, the proportion of the second structural unit is 5 mol% or more (that is, the proportion of the first structural unit is 95 mol% or less), so that the solubility of the polyamide-imide resin in the solvent is improved. The molding defect when the resin layer 3 is formed is suppressed. This ratio is preferably in the range of 10 to 30 mol%.

  The structural unit in the polyamideimide resin is preferably only the first structural unit and the second structural unit, but the structural unit other than the first structural unit and the second structural unit (third structural unit). May further be included. The ratio of the third structural unit to all the structural units in the polyamideimide resin is preferably 20 mol% or less, and more preferably 10 mol% or less.

  The third structural unit has a structure represented by the following structural formula (3), for example.

  A in the structural formula (3) is an aromatic residue. Although it does not specifically limit as a structure of A, The structure shown to following [Chemical Formula 4] can be enumerated.

R ¹ and R ² in [Chemical Formula 4] are selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and an allyl group. However, the same structure as the first structural unit and the second structural unit is excluded from the third structural unit.

  As a method for synthesizing the polyamide-imide resin, an appropriate method such as an isocyanate method or an amine method (an acid chloride method, a low temperature solution polymerization method, a room temperature solution polymerization method, etc.) may be adopted, and among them, the isocyanate method should be adopted. Is preferred.

  In the isocyanate method, for example, trimellitic acid or a derivative thereof (anhydride, halide, etc.) and an aromatic diisocyanate for introducing an aromatic residue are added to an organic solvent, and a catalyst is added if necessary. Added. Under this condition, the polyamideimide resin is synthesized by reacting at a temperature of preferably 10 to 200 ° C. for 1 to 24 hours.

  As the aromatic diisocyanate for introducing the aromatic residue, 4,4'-diisocyanato-3,3'-dimethylbiphenyl and tolylene 2,4-diisocyanate are used. In this case, by adjusting the molar ratio of 4,4′-diisocyanato-3,3′-dimethylbiphenyl and tolylene 2,4-diisocyanate, the structural unit (1) and the structural unit ( The ratio of 2) is adjusted. Moreover, a 3rd structural unit is introduce | transduced into a polyamide-imide resin by further using appropriate aromatic diisocyanate as needed.

  Examples of the organic solvent include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethylsulfoxide, γ -Butyrolactone, cyclohexanone, cyclopentanone and the like. In addition to these solvents, hydrocarbon organic solvents such as toluene and xylene, ether organic solvents such as diglyme, triglyme and tetrahydrofuran, and ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone may be used in combination.

  Examples of the catalyst include tertiary amines, alkali metal compounds, and alkaline earth metal compounds.

  In the amine method, for example, trimellitic acid or a derivative thereof (anhydride, halide, etc.) and an aromatic diamine for introducing an aromatic residue are added to an organic solvent, and further if necessary. A catalyst is added. Under this condition, the polyamideimide resin is synthesized by reacting at a temperature of preferably 0 to 200 ° C. for 1 to 24 hours.

  The molecular weight of the polyamideimide resin is not particularly limited, but the number average molecular weight is preferably in the range of 10,000 to 40,000 from the viewpoint of further improving the solubility of the polyamideimide resin in the solvent. This number average molecular weight is a value measured by gel permeation chromatography.

  One specific example of the polyamide-imide resin is product number HR-16NN manufactured by Toyobo Co., Ltd.

  The first resin composition preferably further contains bismaleimide. In this case, the heat resistance of the insulating layer composed of the first resin layer 3 is further improved. The bismaleimide is not particularly limited, but 4,4′-diphenylmethane bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide, and 1 , 6′-bismaleimide- (2,2,4-trimethyl) hexane is preferably used.

  The ratio of bismaleimide to the total amount of polyamideimide resin and bismaleimide in the first resin composition is preferably in the range of 3 to 30% by mass. When this proportion is 3% by mass or more, the heat resistance of the insulating layer composed of the first resin layer 3 is sufficiently improved, and when this proportion is 30% by mass or less, the first resin layer 3 Good flexibility of the insulating layer made of is maintained. This ratio is preferably in the range of 3 to 20% by mass.

  The first resin composition preferably contains an epoxy compound instead of or together with bismaleimide. Also in this case, the heat resistance of the insulating layer composed of the first resin layer 3 is further improved. The epoxy compound is not particularly limited, but is preferably a polyfunctional epoxy resin having a naphthalene skeleton. Examples of the polyfunctional epoxy resin having a naphthalene skeleton include novolac type epoxy resins, trifunctional type epoxy resins, aralkyl type epoxy resins, and cresol type cocondensation type epoxy resins. Besides these, as the polyfunctional epoxy compound, bisphenol A type epoxy resin, polyphenol type epoxy resin, polyglycidylamine type epoxy resin, alcohol type epoxy resin, alicyclic epoxy resin, novolac type epoxy having phenol skeleton and biphenyl skeleton Resin.

  The ratio of the epoxy compound to the total amount of the polyamideimide resin and the epoxy compound in the first resin composition is preferably in the range of 3 to 30% by mass. When this proportion is 3% by mass or more, the heat resistance of the insulating layer composed of the first resin layer 3 is sufficiently improved, and when this proportion is 30% by mass or less, the first resin layer 3 Good flexibility of the insulating layer made of is maintained. This ratio is preferably in the range of 3 to 20% by mass.

  The first resin composition is prepared by containing a polyamideimide resin and silica in an appropriate solvent, and preferably further containing bismaleimide. When silica is blended with the first resin composition, for example, colloidal silica containing silica can be blended with the first resin composition.

  Solvents include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethylsulfoxide, γ- Examples include butyrolactone, cyclohexanone, and cyclopentanone. In addition to these solvents, hydrocarbon organic solvents such as toluene and xylene, ether organic solvents such as diglyme, triglyme and tetrahydrofuran, and ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone may be used in combination. Moreover, you may mix | blend the solvent used for the synthesis | combination of the polyamideimide resin with a 1st resin composition as it is.

  The ratio of the solvent in the first resin composition is appropriately set in consideration of the applicability of the first resin composition, film formability, etc., but the viscosity of the first resin composition is particularly 200 to 200. The solvent content is preferably adjusted so as to be in the range of 800 cP.

  The first resin composition may contain appropriate additives in addition to the above components.

  The first resin layer 3 is formed by applying and depositing the first resin composition on the metal foil 2. As a method for applying the first resin composition onto the metal foil 2, an appropriate method such as comma coating, die coating, roll coating, gravure coating, or the like may be employed.

  The solvent is volatilized from the first resin composition by heating the first resin composition applied onto the metal foil 2, whereby the first resin layer 3 is formed. The heating temperature in this case may be an appropriate temperature at which the solvent can be volatilized. In particular, the maximum heating temperature during heating is preferably in the range of 230 to 290 ° C. In this case, thermal shrinkage in the process of cooling the first resin layer 3 is suppressed, and thus the metal foil 11 with resin 11 Is effectively suppressed.

  The first resin layer 3 formed in this way has high flexibility and heat resistance, so that the flexibility and heat resistance of the insulating layer formed from the first resin layer 3 are improved. Moreover, since high heat resistance is exhibited without requiring a halogen-based flame retardant, generation of toxic gas and smoke generation during combustion are suppressed. Further, the affinity between the first resin layer 3 and a thermosetting resin such as an epoxy resin is increased.

  The thickness of the first resin layer 3 is not particularly limited, but is preferably in the range of 2 to 15 μm. In this case, sufficiently high flexibility is imparted to the insulating layer formed from the first resin layer 3. From the viewpoint of reducing the size and thickness of the printed wiring board, the first resin layer 3 is preferably thinner. Therefore, the thickness of the first resin layer 3 is preferably in the range of 2 to 10 μm, and more preferably in the range of 2 to 8 μm. In addition, when the 1st resin layer 3 is formed from a polyimide resin, surface treatments, such as a corona discharge process for improving the adhesiveness with the 2nd resin layer 4, are needed, Therefore, by surface treatment In order to avoid damage, the first resin layer 3 needs to have a certain thickness. For this reason, it was difficult to reduce the thickness of the first resin layer 3 formed from a polyimide resin. However, as described above, the first resin layer 3 according to the present embodiment has high adhesiveness with a thermosetting resin such as an epoxy resin, and thus surface treatment for improving adhesiveness is not required. For this reason, in this embodiment, it is not necessary to consider the damage due to the surface treatment, and therefore the first resin layer 3 can be made thinner.

  By forming the second resin layer 4 in the B-stage state on the first resin layer 3, the metal foil 11 with resin in the first embodiment is obtained.

  The second resin layer 4 is formed from, for example, a second resin composition containing an epoxy resin. When the second resin layer 4 is a particle-containing resin layer, the second resin composition further contains silica having an average particle size of 5 to 200 nm and a maximum particle size of 500 nm or less in a range of 2 to 20 phr. When silica is blended with the second resin composition, for example, colloidal silica containing silica can be blended with the second resin composition.

  For example, the second resin composition is applied on the first resin layer 3, and the second resin composition on the first resin layer 3 is heat-dried and semi-cured (B-stage). A second resin layer 4 is formed.

  Here, the 1st resin layer 3 by this embodiment exhibits high adhesiveness between thermosetting resin compositions, such as an epoxy resin composition. For this reason, when forming the 2nd resin layer 4 on the 1st resin layer 3, it is not necessary to perform the surface treatment for adhesiveness improvement to the 1st resin layer 3 previously. For this reason, productivity of the metal foil 11 with a resin becomes high.

  In particular, the second resin composition preferably contains an epoxy resin, a curing agent, and a carbodiimide-modified soluble polyamide.

  The epoxy resin in the second resin composition can contain, for example, one or more selected from glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, and oxidized type epoxy resins. Examples of the glycidyl ether type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, alcohol type epoxy resin and the like. Examples of the glycidyl ester type epoxy resin include hydrophthalic acid type epoxy resin and dimer acid type epoxy resin. Examples of the glycidylamine type epoxy resin include aromatic amine type epoxy resins and aminophenol type epoxy resins. An alicyclic epoxy resin is mentioned as an oxidation type epoxy resin. Examples thereof include an epoxy resin having a naphthalene skeleton, a novolac epoxy resin having a phenol skeleton and a biphenyl skeleton (biphenyl novolac epoxy resin), and a phosphorus-modified epoxy resin (described later). The epoxy resin preferably contains no halogen.

  In particular, the epoxy resin in the second resin composition preferably contains an epoxy resin having a naphthalene skeleton. In this case, the heat resistance, migration resistance, and chemical resistance of the printed wiring board are improved. The epoxy resin having a naphthalene skeleton is preferably at least one of the compounds represented by the following structural formulas (11) to (13). In this case, the printed circuit board has heat resistance, migration resistance, and chemical resistance. Is further improved.

  The curing agent in the second resin composition may include polyamines, modified polyamines, acid anhydrides, hydrazine derivatives, polyphenols, and the like. Examples of polyamines include aliphatic polyamines, alicyclic polyamines, and aromatic polyamines. Among these, examples of the aliphatic polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, and diethylaminopropylamine. Examples of the alicyclic polyamine include isophorone diamine, 1,3-bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norbornene diamine, 1,2-diaminocyclohexane, and laromine. Examples of the aromatic polyamine include diaminodiphenylmethane, metaphenylenediamine, and diaminodiphenylsulfone. Examples of acid anhydrides include hexahydrophthalic anhydride, methyl tetrahydro anhydride, methyl hexahydrophthalic anhydride, methyl nadic anhydride, hydrogenated methyl nadic anhydride, trialkyltetrahydrophthalic anhydride, and methylcyclohexene tetracarboxylic acid. Anhydride, trimellitic anhydride, pyromellitic acid-free, benzophenone tetracarboxylic dianhydride, aliphatic dibasic acid polyanhydride and the like can be mentioned. Examples of the polyphenol-based curing agent include phenol novolak, xylene novolak, bis A novolak, triphenylmethane novolak, biphenyl novolak, dicyclopentadienephenol novolak, and terpene phenol novolak. The curing agent may include an aminotriazine novolac resin, a novolac type phenol resin, and the like.

  In particular, the curing agent preferably contains at least one of an aminotriazine novolac resin represented by the following structural formula (14) and dicyandiamide. In this case, the second resin layer 4 is stably maintained in the B-stage state for a long period of time (storage stability is improved), and the printed circuit board has flame retardancy and chemical resistance. improves.

  The content of the curing agent in the second resin composition is in the range of 10 to 45 mass% with respect to the total amount of the epoxy resin, the curing agent and the carbodiimide-modified soluble polyamide in the second resin composition. Is preferred.

  The carbodiimide-modified soluble polyamide contained in the second resin composition is produced, for example, by reacting a soluble polyamide and a carbodiimide compound at a reaction temperature of, for example, 50 to 250 ° C. in the presence or absence of a solvent. .

  The soluble polyamide is 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass with respect to 100 parts by mass of a mixture of alcohol and at least one of an aromatic organic solvent and a ketone organic solvent. Part or more of the polyamide is completely soluble. Examples of the alcohol include methanol, ethanol, isopropyl alcohol and the like. Examples of the aromatic organic solvent include benzene and toluene. Examples of the ketone organic solvent include cyclohexanone, 2-butanone, and cyclopentanone. The boiling points of these alcohols, aromatic solvents and ketone solvents are preferably 130 ° C. or lower.

  The soluble polyamide is obtained, for example, by subjecting a polyamide other than the soluble polyamide (polyamide before solubilization) to a treatment for solubilization. Examples of the treatment method for solubilization include a method in which a hydrogen atom in an amide group of a polyamide before solubilization is partially substituted with a methoxymethyl group. When a methoxy group is introduced into the polyamide by this method, the crystallinity of the polyamide is inhibited by losing the hydrogen bonding ability from the amide group, thereby increasing the solubility of the polyamide in the solvent. Examples of the treatment method for solubilization include a method in which polyether or polyester is introduced into a polyamide molecule before solubilization to form a copolymer. Examples of the polyamide before solubilization include nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, nylon 46, and the like.

  Specific examples of the soluble polyamide include Zytel 61 (trade name) manufactured by DuPont, Versalon (trade name) manufactured by General Mills, Amilan CM4000 (trade name) manufactured by Toray Industries, and Amilan CM8000 manufactured by Toray Industries, Inc. (Trade name), PA-100 (trade name) manufactured by Fuji Kasei Kogyo Co., Ltd., Toresin (trade name) manufactured by Nagase ChemteX Corporation, and the like.

  A carbodiimide compound is a compound having one or more carbodiimide groups in one molecule. Examples of the carbodiimide compound include a monocarbodiimide compound and a polycarbodiimide compound. A carbodiimide compound is synthesized, for example, by a decarboxylation condensation reaction of various polyisocyanates in a solvent-free or inert solvent at a temperature of about 70 ° C. or higher in the presence of an organic phosphorus compound or organometallic compound as a catalyst. The

  Examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide and the like. Among these, dicyclohexylcarbodiimide or diisopropylcarbodiimide is preferable from the viewpoint of easy availability industrially.

  The polycarbodiimide compound is produced by various methods. For example, a polycarbodiimide compound can be prepared by a known method for producing polycarbodiimide (for example, US Pat. No. 2,941,956, J. Org. Chem. 28, 2069-2075 (1963), Chemical Review 1981, Vol. 81 No. 4). , p619-621).

  The carbodiimide compound is not particularly limited as long as it has one or more carbodiimide groups in one molecule. From the viewpoint of improving the reactivity and hydrolysis stability, 4,4′-dicyclohexylmethanecarbodiimide, etc. A polycarbodiimide compound having two or more carbodiimide groups in the molecule is preferable. In particular, aliphatic or alicyclic polycarbodiimide compounds are preferred. The degree of polymerization of the polycarbodiimide compound is preferably in the range of 2-30, more preferably in the range of 2-20. When the polymerization degree is 2 or more, the heat resistance of the printed wiring board is preferable, and when the polymerization degree is 20 or less, the compatibility between the components in the second resin composition is preferable. .

  Organic diisocyanate is mentioned as polyisocyanate used for manufacture of a polycarbodiimide compound. Examples of organic diisocyanates include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and mixtures thereof. Specifically, 1,5-naphthalene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diene Isocyanate, 2,6-tolylene diisocyanate, mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 2,6-diisopropylphenyl diisocyanate 1,3,5-triisopropylbenzene 2,4-diisocyanate, and the like. Among these, aliphatic (including alicyclic) organic diisocyanates are preferable from the viewpoint of improving the flexibility and moisture resistance of the printed wiring board, and particularly ilophorone diisocyanate and dicyclohexylmethane-4,4′-diisocyanate. Tetramethylxylylene diisocyanate and a mixture thereof are more preferable.

  During the production of the polycarbodiimide compound, the degree of polymerization of the polycarbodiimide compound can be appropriately controlled by stopping the polymerization reaction halfway by cooling the reaction system during the polymerization reaction of the polyisocyanate. In this case, the terminal of the molecule of the polycarbodiimide compound is an isocyanate group. In order to more appropriately control the degree of polymerization of the polycarbodiimide compound, a compound such as a monoisocyanate compound capable of reacting with an isocyanate group (hereinafter referred to as an end-capping agent) is an isocyanate group at the end of the molecule of the polycarbodiimide compound. By reacting with all or a part of the polycarbodiimide compound, all or part of the isocyanate groups of the polycarbodiimide compound may be sealed. When the polymerization degree of the polycarbodiimide compound is appropriately controlled, the compatibility between the soluble polyamide and the polycarbodiimide compound is improved, and the storage stability of the member including the second resin layer 4 is improved.

  Examples of the monoisocyanate compound that can be used as the end-capping agent include phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate.

End capping agents other than monoisocyanate compounds may be used. Examples of the end-capping agent other than the monoisocyanate compound include active hydrogen compounds that can react with an isocyanate group. As such an active hydrogen compound, for example, (i) an aliphatic, aromatic or alicyclic compound having an —OH group, methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, compounds such as polypropylene glycol monomethyl ether; (ii) = diethylamine having an NH group, compounds such as dicyclohexylamine; butylamine with (iii) -NH ₂ group, cyclohexylamine; a (iv) -COOH groups (V) compounds having an epoxy group; (vi) compounds having an epoxy group; (vii) acetic anhydride, methyltetrahydro; compounds having a succinic acid, benzoic acid, cyclohexane and the like; Phthalic anhydride, methyl Kisahidoro anhydride such as phthalic anhydride, and the like.

The decarboxylation condensation reaction of organic diisocyanate can proceed in the presence of a suitable carbodiimidization catalyst. As carbodiimidization catalysts, organophosphorus compounds, organometallic compounds (represented by the general formula M- (OR) _n , where M is titanium (Ti), sodium (Na), potassium (K), vanadium (V), tungsten (W), Hafnium (Hf), Zirconium (ZR), Lead (Pb), Manganese (Mn), Nickel (Ni), Calcium (Ca), Barium (Ba), and other metal elements, R is carbon number 1-20 And an alkyl group or an aryl group, and n represents the valence of M).

  Among these carbodiimidization catalysts, particularly from the viewpoint of improving reaction activity, phospholene oxides are used from among organic phosphorus compounds, and alkoxides of titanium, hafnium, or zirconium from among organometallic compounds. Are preferably used. Specific examples of the phosphorene oxides include 3-methyl-1-phenyl-2-phospholene-1-oxide, 3-methyl-1-ethyl-2-phospholene-1-oxide, and 1,3-dimethyl-2. -Phospholene-1-oxide, 1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 1-methyl-2-phospholene-1-oxide or their double bond isomers Is mentioned. Of these phospholene oxides, 3-methyl-1-phenyl-2-phospholene-1-oxide is preferably used in terms of industrial availability.

  A carbodiimide-modified soluble polyamide is produced by reacting a soluble polyamide and a carbodiimide compound in the presence or absence of a solvent. In this case, a reactive functional group such as a carboxyl group or amino group of the soluble polyamide reacts with a carbodiimide group or an isocyanate group of a carbodiimide compound that can react with these.

  As a method of reacting soluble polyamide and carbodiimide compound in the presence of a solvent, for example, there is a method of adding the soluble polyamide and carbodiimide compound to the solvent and agitating the resulting solution while heating to advance the reaction. Can be mentioned. In particular, it is preferable that the soluble polyamide is first added to a solvent, and a carbodiimide compound is further added to the resulting solution, and then this solution is heated and stirred under reflux (reflux) to advance the reaction. When the solvent is removed from the solution after the reaction under normal pressure or reduced pressure, a carbodiimide-modified soluble polyamide is obtained.

  As a method of reacting the soluble polyamide and the carbodiimide compound in the absence of a solvent, for example, a method of proceeding the reaction by mixing the carbodiimide compound with the soluble polyamide melted by being heated to a temperature equal to or higher than the melting point, Examples thereof include a method in which the reaction proceeds while mixing by melting and kneading a soluble polyamide and a carbodiimide compound with a twin screw extruder.

  When the soluble polyamide reacts with the carbodiimide compound, the ratio of the carbodiimide compound to 100 parts by mass of the soluble polyamide is preferably in the range of 0.5 to 20 parts by mass, and more preferably 1 to 10 parts by mass. In this case, the moisture resistance and heat resistance of the printed wiring board are sufficiently improved, and the plasticity of the printed wiring board is not excessively increased and the impact resistance is not easily lost. That is, when the ratio of the carbodiimide compound is 0.5 parts by mass or more, the moisture resistance and heat resistance of the printed wiring board are sufficiently improved. On the other hand, when the ratio is 20 parts by mass or less, the plasticity of the printed wiring board becomes too high and the impact resistance is hardly deteriorated.

  During the reaction between the soluble polyamide and the carbodiimide compound, it is preferable that the reaction system does not contain a compound that inhibits the modification of the soluble polyamide. In particular, the reaction system contains only the carbodiimide compound, the soluble polyamide and the solvent used as necessary. It is preferable. Specific examples of the compound that inhibits the modification of the soluble polyamide include epoxy resins, amine resins, melamine resins, and phenol resins.

  The reaction time of the soluble polyamide with the carbodiimide compound is appropriately set according to the type of the soluble polyamide or carbodiimide compound, the reaction method, the reaction temperature, etc., but is preferably in the range of 1 to 500 minutes, preferably 5 to 200 minutes. If it is the range, it is still more preferable.

  The temperature of the reaction system during the reaction between the soluble polyamide and the carbodiimide compound is also appropriately set according to the type of the soluble polyamide or carbodiimide compound, the reaction method, the reaction temperature, etc., but is preferably in the range of 50 to 250 ° C. . In particular, when the soluble polyamide and the carbodiimide compound react in the presence of a solvent, the temperature of the reaction system is preferably in the range of 50 to 150 ° C, more preferably in the range of 70 to 130 ° C. On the other hand, when the soluble polyamide and the carbodiimide compound react in the absence of a solvent, the temperature of the reaction system is preferably in the range of 130 to 250 ° C, more preferably 150 to 220 ° C. When the temperature of this reaction system is 50 ° C. or higher, the reaction between the soluble polyamide and the carbodiimide compound is sufficiently fast and the modification of the soluble polyamide occurs rapidly, which is preferable from an industrial viewpoint. Furthermore, it is preferable that the temperature of the reaction system is 250 ° C. or less because the product is hardly deteriorated due to decomposition of the resin or the like.

  Thus, when soluble polyamide and a carbodiimide compound react, soluble polyamide will modify and it will become carbodiimide modified soluble polyamide. As this reaction proceeds, the carbodiimide group of the carbodiimide compound decreases accordingly. For this reason, when each of the raw material and the product is measured by infrared spectroscopy, the peak attributed to the carbodiimide group decreases in the infrared absorption spectrum measured for the product. Furthermore, when differential thermogravimetric analysis of the raw material and the product is performed, a plurality of absorption peaks such as an absorption peak due to the amide resin and an absorption peak due to the carbodiimide resin are observed in the raw material, but in the product, the endothermic peak is It is aggregated into one. These confirm that the soluble polyamide has been modified.

  A composition containing a carbodiimide-modified soluble polyamide is excellent in storage stability as compared with a composition containing a soluble polyamide and a carbodiimide compound. That is, a composition containing a soluble polyamide and a carbodiimide compound thickens when it is made into a solution, and becomes easier to gel, whereas a composition containing a carbodiimide-modified soluble polyamide is less susceptible to changes such as thickening, Long-term storage is possible.

  The content of the carbodiimide-modified soluble polyamide in the second resin composition is 20 to 70% by mass with respect to the total amount of the epoxy resin, the curing agent, and the carbodiimide-modified soluble polyamide in the second resin composition. It is preferable that it is the range of these. When the content of the carbodiimide-modified soluble polyamide is 20% by mass or more, the flexibility of the printed wiring board is improved, and when the content is 70% by mass or less, the flame retardancy and heat resistance of the printed wiring board are improved. To do.

  The second resin composition may contain a curing accelerator such as 2-ethyl-4-methylimidazole as necessary.

  It is preferable that the second resin composition further contains a phenoxy resin. In this case, the flexibility of the printed wiring board is further improved. The phenoxy resin may include a bisphenol A type phenoxy resin, a bisphenol A / bisphenol F type copolymer phenoxy resin, a phosphorus-modified phenoxy resin (described later), and the like. The content of the phenoxy resin in the second resin composition is preferably in the range of 5 to 30% by mass with respect to the total amount of the second resin composition.

  The second resin composition preferably also contains at least one of a phosphorus-based flame retardant such as a phosphorus-modified epoxy resin, a phosphorus-modified phenoxy resin, and phosphazene. In this case, the flame retardancy of the printed wiring board is further improved. The total ratio of the contents of the phosphorus-modified epoxy resin, phosphorus-modified phenoxy resin, and phosphorus flame retardant with respect to the total amount of the second resin composition is preferably in the range of 10 to 40% by mass.

  The phosphorus-modified epoxy resin can be obtained, for example, by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with 1,4-naphthoquinone and further reacting with a cresol novolac resin.

  The main molecular skeleton of the phosphorus-modified phenoxy resin is composed of a phenoxy resin, and one mole of the phosphorus-modified phenoxy resin contains, for example, several phosphorus elements (about 1 to 5).

  Examples of the phosphorus flame retardant include phosphazene, monomeric phosphate ester, condensed phosphate ester, reactive phosphorus flame retardant, phosphate, and phosphazene compound. Specific examples of the monomeric phosphate ester include triphenyl phosphate, tricresyl phosphate, trixynyl phosphate, triethyl phosphate, cresyl diphenyl phosphate, xylyl diphenyl phosphate, cresyl bis (di-2,6-xylenyl) phosphate, 2 -Ethylhexyl diphenyl phosphate and the like. Specific examples of the condensed phosphate ester include resorcinol bis (diphenyl) phosphate, bisphenol A bis (diphenyl) phosphate, bisphenol A bis (dicresyl) phosphate, resorcinol bis (di-2,6-xylenyl) phosphate, and the like. . Specific examples of reactive phosphorus flame retardants include bisphenol A bisphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide, 2- (diphenylphosphinyl) hydroquinone, and the like. Is mentioned. Specific examples of the phosphate include melamine phosphate, dimelamine phosphate, melamine pyrophosphate, dimelamine pyrophosphate, melamine polyphosphate, ethylenediamine phosphate, and the like. Specific examples of the phosphazene compound include phosphonitrile acid phenyl ester, cyanophenol / phenol mixed substituted cyclophosphazene, phosphonitrile chloride / hydroquinone / phenol condensate, and the like.

  The second resin composition is prepared by blending the above components. Furthermore, the 2nd resin composition may contain the organic solvent for viscosity adjustment as needed.

  When the second resin composition thus obtained contains a carbodiimide-modified soluble polyamide, the storage stability, adhesion, flexibility, and fillability of the second resin composition are increased. In other words, carbodiimide-modified soluble polyamides are produced by the reaction of reactive functional groups such as carboxyl groups and amino groups possessed by soluble polyamides with carbodiimide groups and isocyanate groups of carbodiimide compounds which can react with these, so It is difficult to react with epoxy resin. Therefore, the storage stability of the second resin composition is increased, and the storage stability and press moldability of the metal foil with resin 11 including the second resin layer 4 formed from the second resin composition are improved. Get higher. Furthermore, the handleability and processability (storage stability and press formability) of the second resin composition and the second resin layer 4 and various properties of the printed wiring board (adhesion, flexibility, filling properties, etc.) Can be compatible.

  Furthermore, when the second resin composition contains the carbodiimide-modified soluble polyamide, the insulating properties of the second resin layer 4 are improved, and the flame retardancy, heat resistance, and chemical resistance are further improved.

  From the second resin composition having the above composition, the second resin layer 4 having a high resin flow can be formed. The resin flow of the second resin layer 4 adjusts the heating temperature and the heating rate when the second resin layer 4 is formed by heating and drying the coating film of the second resin composition. Therefore, it can be easily adjusted.

  The second resin composition 4 is formed on the first resin layer 3, and the second resin composition 4 is further heated and dried to be semi-cured, whereby the second resin layer 4 can be formed. In this case, the second resin layer 4 made of a semi-cured product of the second resin composition is formed. As a method for applying the second resin composition, an appropriate method such as a comma coater, a die coater, a roll coater, or a gravure coater may be employed. Although the heating conditions at the time of heating and drying of the second resin composition are appropriately set, the heating temperature is preferably in the range of 130 ° C. to 160 ° C., and the heating time is preferably in the range of 2 to 10 minutes.

  The thickness of the second resin layer 4 is not particularly limited, but is preferably in the range of 10 to 40 μm from the viewpoint of further improving the filling property and further reducing the thickness of the flexible printed wiring board.

  The resin-coated metal foil 11 thus configured is used for producing a printed wiring board, and particularly preferably for producing a flexible printed wiring board or a flex-rigid printed wiring board. That is, the metal foil 2 in the metal foil with resin 11 is used for forming a conductor wiring in the printed wiring board, and the first resin layer 3 and the second resin layer 4 in the metal foil with resin 11 are Used to form an insulating layer in a printed wiring board. For example, the printed wiring board can be multilayered by laminating the resin-attached metal foil 11 on the core material.

  The base material 1 for flexible printed wiring board manufacture which concerns on 2nd embodiment of this invention is shown in FIG. This flexible printed wiring board manufacturing substrate 1 is a flexible metal-clad substrate 12 (single-sided flexible metal-clad substrate). The metal-clad substrate 12 includes a metal foil 2 and a first resin layer 3 laminated on one surface in the thickness direction of the metal foil 2. The thickness of the first resin layer 3 is preferably 2 to 15 μm. The first resin layer 3 is composed of a particle-containing resin layer. That is, the first resin layer 3 contains silica having an average particle diameter of 5 to 200 nm and a maximum particle diameter of 500 nm or less in a range of 2 to 20 phr.

  The metal foil 2 in the present embodiment can have the same configuration as the metal foil 2 in the first embodiment.

  The first resin layer 3 in this embodiment is the same as the first resin layer 3 containing silica having an average particle diameter of 5 to 200 nm and a maximum particle diameter of 500 nm or less in the range of 2 to 20 phr in the first embodiment. It has a configuration and can be formed by the same method as the first resin layer 3 in the first embodiment. That is, as a resin composition for forming the first resin layer 3 in the present embodiment, silica having an average particle diameter of 5 to 200 nm and a maximum particle diameter of 500 nm or less in the first embodiment is within a range of 2 to 20 phr. The 1st resin composition to contain can be used.

  The first resin layer 3 formed in this way has high flexibility and heat resistance, so that the flexibility and heat resistance of the insulating layer formed from the first resin layer 3 are improved. Moreover, since high heat resistance is exhibited without requiring a halogen-based flame retardant, generation of toxic gas and smoke generation during combustion are suppressed. Further, the affinity between the first resin layer 3 and a thermosetting resin such as an epoxy resin is high. For this reason, in producing a multilayer printed wiring board by laminating the metal-clad base material 12 on an appropriate core material, the metal-clad base material 12 and the core material are joined via a thermosetting resin composition such as an epoxy resin composition. In this case, it is not necessary to previously apply a surface treatment for improving the adhesion to the first resin layer 3, and thus the productivity of the printed wiring board is improved. Moreover, since it is not necessary to consider the damage by surface treatment, the 1st resin layer 3 can be reduced in thickness.

  The printed wiring board can be multilayered by laminating the highly flexible metal-clad base material 12 thus configured on the core material via a thermosetting resin composition such as an epoxy resin composition. A bonding sheet can also be used as the thermosetting resin composition.

  The base material 1 for flexible printed wiring board manufacture which concerns on 3rd embodiment of this invention is shown in FIG. This flexible printed wiring board manufacturing substrate 1 is a bonding sheet 13. The bonding sheet 13 is composed of a particle-containing resin layer in a semi-cured state (B stage state). This particle-containing resin layer has, for example, the same configuration as the second resin layer 4 containing silica having an average particle diameter of 5 to 200 nm and a maximum particle diameter of 500 nm or less in the range of 2 to 20 phr in the first embodiment. Moreover, as a resin composition used in order to form this particle-containing resin layer, for example, silica having an average particle diameter of 5 to 200 nm and a maximum particle diameter of 500 nm or less in the first embodiment is contained in a range of 2 to 20 phr. A second resin composition can be used.

  As shown in FIG. 3, the bonding sheet 13 may be used in a state of being laminated on the release film 26. As the release film 26, for example, an appropriate resin film such as a polyethylene terephthalate film is used.

  The bonding sheet 13 can be formed, for example, by applying the second resin composition on the release film 26 and further heating and drying the second resin composition to be semi-cured. In this case, a bonding sheet 13 made of a semi-cured product of the second resin composition is formed. As a method for applying the second resin composition, an appropriate method such as a comma coater, a die coater, a roll coater, or a gravure coater may be employed. Although the heating conditions at the time of heating and drying of the second resin composition are appropriately set, the heating temperature is preferably in the range of 130 ° C. to 160 ° C., and the heating time is preferably in the range of 2 to 10 minutes.

  The thickness of the bonding sheet 13 is not particularly limited, but is preferably in the range of 10 to 40 μm from the viewpoint of further improving the filling property and further reducing the thickness of the flexible printed wiring board.

  A manufacturing process of the flexible printed wiring board 15 according to the fourth embodiment of the present invention is shown in FIG. In the present embodiment, the resin-coated metal foil 11 according to the first embodiment is used for multilayering the flexible printed wiring board 15.

  In this embodiment, first, as shown to Fig.4 (a), the flexible laminated board 5 provided with the 1st insulating layer 6 and the metal foil 7 laminated | stacked on the single side | surface or both surfaces of the 1st insulating layer 6. FIG. Is prepared. The first insulating layer 6 is easily flexible. The first insulating layer 6 is made of various highly flexible insulating materials such as polyimide resin, liquid crystal polymer, polyethylene terephthalate resin, and polyethylene naphthalate resin. Although the thickness of the 1st insulating layer 6 is set suitably, it is preferable that it is the range of 12-50 micrometers. Although the material in particular of metal foil 7 is not restrict | limited, A copper foil is mentioned as the example. The flexible laminate 5 is formed, for example, by bonding or heat-sealing a metal foil 7 to the first insulating layer 6.

  As shown in FIG. 4B, the first conductor wiring 8 is formed by performing a process such as an etching process on the metal foil 7 of the flexible laminate 5. Furthermore, an opening may be formed in the first insulating layer 6 and a via hole may be formed by performing hole plating in the opening. Thereby, the core material 9 comprised from the 1st insulating layer 6 and the 1st conductor wiring 8 laminated | stacked on this 1st insulating layer 6 is obtained. The first conductor wiring 8 may be formed only on one surface in the thickness direction of the first insulating layer 6, or may be formed on both surfaces in the thickness direction of the first insulating layer 8. .

  As shown in FIG. 4C and FIG. 4D, the resin-coated metal foil 11 according to the first embodiment is laminated on the core material 9. In this case, the metal foil with resin 11 is overlaid on each of both surfaces of the core material 9 so that the first conductor wiring 8 is covered with the second resin layer 4. The resin-attached metal foil 11 may be stacked only on one side of the core material 9. Subsequently, the resin-attached metal foil 11 and the core material 9 are pressurized and heated in the direction in which they are laminated. As a result, the second resin layer 4 is first softened and filled between the lines of the first conductor wiring 8, and further, when via holes are formed in the first insulating layer 6, the via holes are also filled. The Subsequently, the second resin layer 4 is thermally cured. Thereby, an insulating layer (second insulating layer 10) made of the cured product of the first resin layer 3 and the second resin layer 4 is formed.

  When the core material 9 and the resin-coated metal foil 11 are laminated and integrated by the above method, the first conductor wiring is formed on each of both surfaces in the thickness direction of the first insulating layer 6 as shown in FIG. 8. A laminate 14 having a structure in which the second insulating layer 10 and the metal foil 2 are sequentially laminated is obtained. The laminate 14 has a structure in which the first conductor wiring 8, the second insulating layer 10, and the metal foil 2 are sequentially laminated only on one surface in the thickness direction of the first insulating layer 6. Also good.

  The outermost metal foil 2 derived from the resin-attached metal foil 11 in the laminate 14 is subjected to a process such as an etching process, whereby a conductor wiring (second wire) is formed as shown in FIG. Conductor wiring 25) is formed.

  Moreover, a hole is formed in the second insulating layer 10 by applying laser processing to the laminate 14. The inner surface of the hole is subjected to desmear treatment with a desmear solution such as an alkaline permanganate solution. Further, a plating process (hole plating) is performed on the inner surface of the hole. As a result, a via hole 27 is formed in the second insulating layer 10. In the present embodiment, when laser processing is performed in this way, laser processability is improved as described above, and therefore, a plating layer is easily formed uniformly when plating processing is performed. For this reason, the conduction stability of the via hole 27 is improved.

  The manufacturing process of the flexible printed wiring board 15 which concerns on 5th embodiment of this invention is shown in FIG. In this embodiment, in order to make the flexible printed wiring board 15 multilayer in the fourth embodiment, instead of the metal foil 11 with resin, the metal-clad base material 12 and the third embodiment according to the second embodiment are used. Such a bonding sheet 13 is used.

  In this embodiment, first, similarly to the fourth embodiment, a flexible laminate 5 including a first insulating layer 6 and a metal foil 7 is prepared as shown in FIG. 5, the core material 9 including the first insulating layer 6 and the first conductor wiring 8 is formed as shown in FIG.

  As shown in FIGS. 5C and 5D, the core sheet 9 is sequentially laminated with the bonding sheet 13 according to the third embodiment and the metal-clad base material 12 according to the second embodiment. In this case, the bonding sheet 13 is overlaid on each of both surfaces of the core material 9 so as to cover the first conductor wiring 8, and the first resin layer 3 of the metal-clad base material 12 is overlaid on the bonding sheet 13. The bonding sheet 13 and the metal-clad base material 12 may be stacked only on one side of the core material 9. Subsequently, the metal-clad base material 12, the bonding sheet 13, and the core material 9 are pressurized and heated in the direction in which they are laminated. As a result, the bonding sheet 13 is first softened and filled between the lines of the first conductor wiring 8, and when via holes are formed in the first insulating layer 6, the via holes are also filled. Subsequently, the bonding sheet 13 is thermally cured. Thereby, an insulating layer (second insulating layer 10) composed of the first resin layer 3 and a cured product of the bonding sheet 13 is formed.

  As a result, as shown in FIG. 5D, the first conductor wiring 8, the second insulating layer 10, and the metal foil 2 are sequentially laminated on both surfaces of the first insulating layer 6 in the thickness direction. A laminate 14 having the structure is obtained. The laminate 14 has a structure in which the first conductor wiring 8, the second insulating layer 10, and the metal foil 2 are sequentially laminated only on one surface in the thickness direction of the first insulating layer 6. Also good.

  The outermost metal foil 2 derived from the metal-clad base material 12 in the laminate 14 is subjected to a process such as an etching process so that a conductor wiring (second conductor) is formed as shown in FIG. A wiring 25) is formed.

  Moreover, a hole is formed in the laminate 14 by performing laser processing on the laminate 14. Furthermore, the via hole 27 is formed by performing a plating process (hole plating) on the inner surface of the hole. In the present embodiment, when laser processing is performed in this way, laser processability is improved as described above, and therefore, a plating layer is easily formed uniformly when plating processing is performed. For this reason, the conduction stability of the via hole 27 is improved.

  A manufacturing process of the flex-rigid printed wiring board 24 according to the sixth embodiment of the present invention is shown in FIG.

  The flex-rigid printed wiring board 24 includes a plurality of rigid portions 23 and a flex portion 22 that connects between the rigid portions 23. The rigid portion 23 is a rigid portion having a hardness and strength that can withstand the weight of the mounted component and can be fixed to the housing. In addition, the flex portion 22 is a flexible portion that is configured by a portion of the core material 16 that is not multilayered and is flexible. A via hole 27 is formed in the rigid portion 23. The flex-rigid printed wiring board 24 is used in a small and lightweight device such as a portable electronic device by being bent at the flex portion 22 and housed in a housing or the like.

  The flex-rigid printed wiring board 24 is manufactured by using the flexible printed wiring board 15 in which the via hole 27 according to the fourth or fifth embodiment is formed as the core material 16.

  The rigid portion 23 can be formed by multilayering the core material 16 except for the portion that becomes the flex portion 22. A technique for multilayering is not particularly limited, and a known technique is used. In this embodiment, a build-up method using a metal foil 17 with resin for multilayering is employed.

  As shown in FIG. 6A, the metal foil with resin 17 includes a metal foil 18 and a resin layer 19 laminated on one side of the metal foil 18. The resin-attached metal foil 17 is formed by, for example, applying a thermosetting resin composition such as an epoxy resin composition to the mat surface of a metal foil 18 such as a copper foil, and semi-curing the thermosetting resin composition (B stage state). It is manufactured by forming the resin layer 19 by heating and drying until it becomes. The thickness of the metal foil 18 is preferably in the range of 6 to 18 μm, and the thickness of the resin layer 19 is preferably in the range of 10 to 100 μm.

  As shown in FIG. 6B, in each of a plurality of regions in the core material 16 where the rigid portion 23 is formed, the resin layer 19 of the metal foil 17 with resin is superimposed on each of both surfaces of the core material 16, and this state Then, the resin layer 19 is bonded to the core material 16 and the resin layer 19 is cured to form an insulating layer (third insulating layer 20). The molding conditions in this case are appropriately set. For example, the molding pressure is set in the range of 1 to 3 MPa, and the molding temperature is set in the range of 160 to 200 ° C.

  Subsequently, as shown in FIG. 6C, a conductor wiring (third conductor wiring 21) is formed by performing an etching process or the like on the metal foil 18 derived from the metal foil 17 with resin. Thereby, the rigid part 23 is formed and the flex part 22 is formed between the adjacent rigid parts 23. A through hole, a via hole, or the like may be formed in the rigid portion 23 as necessary. Further, the rigid portion 23 may be further multilayered by a build-up method or the like.

[Synthesis of carbodiimide compounds]
590 g of 4,4′-dicyclohexylmethane diisocyanate, 62.6 g of cyclohexyl isocyanate and 6.12 g of carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) were blended to obtain a mixture. The reaction was allowed to proceed by heating the mixture at 180 ° C. for 48 hours. As a result, 4,4′-dicyclohexylmethanecarbodiimide resin (degree of polymerization = 10) was synthesized.

[Synthesis of carbodiimide-modified soluble polyamide]
To a 1 liter separable flask, add 50.0 g of ester copolymerized amide resin (trade name CM8000, manufactured by Toray Industries, Inc.) and 450.0 g of a mixed solvent of isopropyl alcohol and toluene (mass mixing ratio 4: 6). These were dissolved by stirring. To the solution in the separable flask thus obtained, 5.0 g of a carbodiimide compound (4,4′-dicyclohexylmethanecarbodiimide resin) was added. Subsequently, this separable flask was immersed in an oil bath at 120 ° C., the solution in the separable flask was heated and stirred for 3 hours under reflux, and then the solvent was removed by drying under reduced pressure. Thereby, a solution containing a carbodiimide-modified soluble polyamide was obtained.

When infrared spectrophotometry was performed on this carbodiimide-modified soluble polyamide, an absorption peak indicating the presence of a carbodiimide group was observed at 2120 cm ⁻¹ . Further, when differential scanning calorimetry was performed on the carbodiimide-modified soluble polyamide, one endothermic peak was observed. The carbodiimide-modified soluble polyamide had a glass transition temperature (Tg) of 120 ° C., a 5% weight loss temperature of 320 ° C., and a solution viscosity of 860 mPa · s.

[Example 1]
(Preparation of first resin composition)
192 g (50 mol%) trimellitic anhydride (manufactured by Nacalai Tesque), 211 g (40 mol%) of 4,4′-diisocyanato-3,3′-dimethylbiphenyl, 35 g (10 mol) of tolylene 2,4-diisocyanate %), 1 g of diazabicycloundecene (manufactured by Sun Apro Co., Ltd.), and 2482 g of N, N-dimethylacetamide (DMAC, manufactured by Nacalai Tesque Co., Ltd.) were obtained to obtain a mixture having a polymer concentration of 15% by mass. The mixture was heated to 100 ° C. over 1 hour, and then the mixture was maintained at 100 ° C. for 6 hours to proceed the reaction.

  The polymer concentration was then adjusted to 10 wt% by adding an additional 1460 g of DMAC to the mixture, and then the mixture was cooled to room temperature. As a result, a resin solution containing a polyamideimide resin was obtained.

  Subsequently, colloidal silica (dispersion medium methyl ethyl ketone, solid content concentration 50% by mass) containing spherical silica having a particle size shown in the table below is added to the resin solution, and the ratio of silica to 100 parts by mass of resin solid content in the liquid. (Phr) was added so as to have the ratio shown in the table.

  As a result, a resin solution (first resin composition) in which polyamideimide was dissolved was obtained. This resin solution is a yellowish brown transparent liquid, and it is thus confirmed that the polyamideimide is sufficiently dissolved.

(Preparation of second resin composition)
The epoxy resin, epoxy resin curing agent, carbodiimide-modified soluble polyamide, phosphazene, and curing accelerator shown in the following table were mixed in a container so that the ratio in the solid content of the resin would be shown in the table. Thus, a second resin composition having a solid content of 30% by mass was prepared.

(Production of metal foil with resin)
The first resin composition was applied on one side of a copper foil having a thickness of 12 μm using a comma coater and a dryer connected thereto. Subsequently, the first resin composition was heated at 200 ° C. for 4 minutes, and then heated and dried at 250 ° C. for 10 minutes using a dryer. As a result, a first resin layer having a thickness of 7 μm was formed on the copper foil. This obtained the metal-clad base material provided with the metal foil and the 1st resin layer laminated | stacked on the single side | surface of this metal foil.

  Without applying any surface treatment to the first resin layer in this metal-clad substrate, using a comma coater and a dryer connected thereto, the second resin composition was applied on the first resin layer, Subsequently, the second resin composition was heat-dried at 150 ° C. for 3 minutes. As a result, a second resin layer in a B stage state having a thickness of 30 μm was formed.

  Thereby, metal foil with resin provided with metal foil, the 1st resin layer, and the 2nd resin layer was obtained.

[Examples 2 to 16, Comparative Examples 1 to 3]
In Example 1, the composition of the first resin composition and the composition of the second resin composition were changed as shown in the table below. When bismaleimide was blended in the first resin composition, the ratio of the polyamideimide resin and bismaleimide in the resin solid content was as shown in the table below. When blending spherical silica with the second resin composition, colloidal silica containing spherical silica having a particle size shown in the following table (dispersion medium methyl ethyl ketone, solid content concentration 50% by mass) It added so that the ratio (phr) of the silica with respect to 100 mass parts of resin solid content might become the ratio shown in a table | surface. Other than that was obtained by the same method and the same conditions as in Example 1 to obtain a metal foil with a resin including a metal foil, a first resin layer, and a second resin layer.

[Evaluation test]
About the resin-coated metal foil obtained in each Example and Comparative Example, as follows, chemical resistance, copper foil peel strength, solder heat resistance, flexibility, circuit filling properties, flame resistance, migration resistance, and Laser workability was evaluated. The evaluation results are shown in the table below.

(Folding resistance)
A single-sided flexible substrate comprising a polyimide film having a thickness of 25 μm and a copper foil having a thickness of 18 μm laminated on one side of the polyimide film was prepared. Conductor wiring was formed by patterning the copper foil on this single-sided flexible substrate. A laminated body was obtained by stacking a second resin layer of a metal foil with resin on each of both surfaces of this single-sided flexible substrate and heating and pressing them at 180 ° C. for 1 hour. The metal foil disposed on each of both surfaces of the laminate was removed by etching, thereby obtaining a sample.

  This sample was tested by the MIT method. The measurement conditions were R = 0.38 mm, a load of 500 g, and the number of bendings per hour was 175 times per minute. As a result, the folding resistance (flexibility) was evaluated based on the number of bendings required until the conductor wiring could not be conducted.

(Laser workability)
A double-sided flexible substrate comprising a polyimide film having a thickness of 25 μm and a copper foil having a thickness of 18 μm laminated on both sides of the polyimide film was prepared. A four-layer plate was prepared by overlaying a second resin layer of a metal foil with a resin on each of both surfaces of this double-sided flexible substrate, and heating and pressing them at 180 ° C. for 1 hour. A conformal mask having a diameter of 100 μm was formed by etching the outermost copper foil of the four-layer plate. Using this conformal mask, a hole was formed in the insulating layer by performing laser processing using a carbon dioxide laser (manufactured by Hitachi Via Mechanics Co., Ltd.). Subsequently, desmear treatment was performed on the inner surface of the hole using an alkaline permanganate solution.

  Then, the presence or absence of the resin residue was confirmed by visually observing the inner surface of the hole. In addition, the inner surface of the hole was observed by SEM, and the degree of roughness of the inner surface of the hole was confirmed.

(Copper foil peel strength)
A second resin layer of a resin-coated metal foil was placed on each of both surfaces of a polyimide film having a thickness of 25 μm, and these were heated and pressed at 180 ° C. for 1 hour to prepare a sample.

  The peeling strength when the copper foil of the outermost layer of this sample was peeled in the 90 ° direction was measured, and this was used as an index of adhesion between the first resin layer and the second resin layer.

(chemical resistance)
Two metal foils with resin were stacked with the second resin layers facing each other, and these were heated and pressed at 180 ° C. for 1 hour to obtain a sample. All the copper foil in this sample was removed by etching. Next, the sample was immersed in an aqueous sodium hydroxide solution (concentration: 3% by mass, temperature: 40 ° C.) for 3 minutes, then taken out, washed with water, and thoroughly wiped off with a clean dry cloth. Subsequently, changes in appearance such as discoloration, swelling, and peeling of the sample were immediately observed visually. As a result, the case where the appearance change was not recognized was evaluated as “pass”, and the case where the appearance change was observed was evaluated as “fail”.

(Solder heat resistance)
A second resin layer 4 of a metal foil with resin was placed on each of both surfaces of a polyimide film having a thickness of 25 μm, and these were heated and pressed at 180 ° C. for 1 hour to prepare a sample. The sample was immersed in a solder bath heated to 260 ° C. and a solder bath heated to 288 ° C. for 60 seconds, and the appearance of the sample was observed. As a result, the sample was evaluated as “pass” when no abnormality in appearance such as swelling or peeling was observed, and “failed” when abnormality in appearance was observed.

(Circuit fillability)
A single-sided flexible printed wiring board comprising an insulating layer made of a polyimide film and a comb-shaped electrode formed on one side of the insulating layer was prepared. The comb-shaped electrode was formed by etching a rolled copper foil having a thickness of 35 μm. A sample was prepared by stacking a second resin layer of a metal foil with resin on the surface of the single-sided flexible printed wiring board on which the comb-shaped electrodes were formed, and heating and pressing them at 180 ° C. for 1 hour. The filling property of the resin between the conductor wirings in the comb electrode in this sample was visually observed, and the case where no filling was observed was evaluated as “pass”, and the case where unfilling was observed was evaluated as “fail”.

(Flame retardance)
A second resin layer of a metal foil with resin was stacked on each of both surfaces of a polyimide film having a thickness of 25 μm, and these were heated and pressed at 180 ° C. for 1 hour to obtain a laminate. The metal foil disposed on each of both surfaces of the laminate was removed by etching, thereby obtaining a sample. The flame retardancy of this sample was evaluated according to the flame retardancy criteria of 94 VTM according to UL94. As a result, the case of conforming to 94VTM-0 was evaluated as “pass”, and the case where it was not so was evaluated as “fail”.

(Migration resistance)
A single-sided flexible printed wiring board comprising an insulating layer made of a polyimide film and a comb-shaped electrode formed on one side of the insulating layer was prepared. A sample was prepared by stacking a second resin layer of a metal foil with resin on the surface of the single-sided flexible printed wiring board on which the comb-shaped electrodes were formed, and heating and pressing them at 180 ° C. for 1 hour. While this sample was exposed to an environment of 85 ° C./85% RH, a voltage of 10 V was applied to the comb electrode for 250 hours. Subsequently, the presence or absence of migration was evaluated by visually observing the sample. As a result, the case where migration was not recognized was evaluated as “pass”, and the case where migration was recognized was evaluated as “fail”.

In addition, the detail of the raw material in a table | surface is as follows.
Bismaleimide 1: 4,4′-diphenylmethane bismaleimide (manufactured by Daiwa Kasei Kogyo Co., Ltd., product number BMI-1000).
Bismaleimide 2: bisphenol A diphenyl ether bismaleimide (manufactured by Daiwa Kasei Kogyo Co., Ltd., product number BMI-4000).
-Epoxy resin having a naphthalene skeleton (1): Nippon Kayaku Co., Ltd., product number NC-7000L.
-Epoxy resin having a naphthalene skeleton (2): manufactured by DIC Corporation, part number HP-4700.
-Epoxy resin (3) having a naphthalene skeleton: manufactured by DIC Corporation, product number HP-4770.
Phenoxy resin: manufactured by Nippon Steel Chemical Co., Ltd., product number YP-50, methyl ethyl ketone solution having a resin solid content of 65% by mass.
Phosphorus-modified epoxy resin: manufactured by Nippon Steel Chemical Co., Ltd., product number FX-305EK70, methyl ethyl ketone solution having a resin solid content of 70% by mass.
Carbodiimide-modified soluble polyamide: synthetic product according to this example, mixed solvent solution of isopropyl alcohol and toluene (mass ratio 4: 6), solid content concentration 11% by mass.
-Phosphazene: manufactured by Otsuka Chemical Co., Ltd., product number SPB-100.
Curing accelerator: 2-ethyl-4-methylimidazole, Shikoku Kasei Kogyo Co., Ltd., product number 2E4MZ.

  As can be seen from the above table, it was confirmed that each example had high flexibility, good laser processability, and excellent solder heat resistance and migration resistance.

DESCRIPTION OF SYMBOLS 1 Base material for flexible printed wiring board manufacture 2 Metal foil 3 First resin layer 4 Second resin layer 15 Printed wiring board 24 Flex-rigid printed wiring board

Claims (9)

Comprising at least one particle-containing resin layer containing silica having an average particle size of 5 to 200 nm and a maximum particle size of 500 nm or less in a range of 2 to 20 phr ;
A first resin layer and a semi-cured second resin layer laminated on the first resin layer, wherein at least one of the first resin layer and the second resin layer, The particle-containing resin layer,
The first resin layer is formed from a first resin composition containing a polyamideimide resin and a bismaleimide,
The structural unit constituting the polyamide-imide resin includes a first structural unit represented by the following structural formula (1) and a second structural unit represented by the following structural formula (2). ratio of the second constitutional unit structural units to the total of the second constitutional unit is 5 to 35 mol% of the range der Ru flexible printed wiring board manufacturing base material.
The substrate for manufacturing a flexible printed wiring board according to claim 1, further comprising a metal foil directly or indirectly laminated on the particle-containing resin layer. The bismaleimide is 4,4′-diphenylmethane bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide, and 1,6′-bis. The substrate for producing a flexible printed wiring board according to claim 1 or 2 , which is at least one selected from maleimide- (2,2,4-trimethyl) hexane. Ratio of the bismaleimide to the total amount of the polyamide-imide resin and the bismaleimide of the first resin composition is according to any one of claims 1 to 3 in the range of 3 to 30 wt% Base material for manufacturing flexible printed wiring boards. The substrate for manufacturing a flexible printed wiring board according to any one of claims 1 to 4 , wherein the thickness of the first resin layer is in a range of 2 to 15 µm. The flexible printed wiring board provided with the insulating layer formed from said 1st resin layer and said 2nd resin layer in the base material for flexible printed wiring board manufacture of Claim 1 . The insulating layer formed from said 1st resin layer and said 2nd resin layer in the base material for flexible printed wiring board manufacture of Claim 2 , and the said metal foil in the said base material for flexible printed wiring board manufacture A flexible printed wiring board comprising: a conductor wiring formed from: A flex-rigid printed wiring board comprising a plurality of rigid parts and a flex part that connects adjacent rigid parts,
A flex-rigid printed wiring board comprising an insulating layer formed of the first resin layer and the second resin layer in the substrate for manufacturing a flexible printed wiring board according to claim 1 . A flex-rigid printed wiring board comprising a plurality of rigid parts and a flex part that connects adjacent rigid parts,
The insulating layer formed from said 1st resin layer and said 2nd resin layer in the base material for flexible printed wiring board manufacture of Claim 2 , and the said metal foil in the said base material for flexible printed wiring board manufacture A flex-rigid printed wiring board comprising conductor wiring formed from