JP2005325329A - Polyamide-imide resin, resin composition and metal-clad laminated body using the same resin or resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively produce a two-layer CCL and a two-layer flexible printed board excellent in processability, flexibility, resistance to HAI(high-current arc ignition) and hygroscopic properties and resins and insulator films used therefor. <P>SOLUTION: The polyamide-imide resin comprises at least one kinds of component selected from a group consisting of components represented by general formula (1), general formula (2), general formula (3) and general formula (4) as an essential component. In the polyamide-imide resin, the copolymerization ratio (mole ratio) of [general formula (1)] to [general formula (2)+general formula (3)+general formula (4)] is (99/1) to (5/95). In the general formula (1) and general formula (2), X is an oxygen atom, CO or SO<SB>2</SB>or a direct bond and n is 0 or 1. In the general formula (3), Y is an oxygen atom, CO or OOC-R-COO and n is o or 1 and R is a divalent organic group. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a flexible metal-clad laminate, a flexible printed board, a heat-resistant resin composition used therein, and an insulating film, which are obtained by applying a heat-resistant resin solution to a metal foil and drying it. More specifically, it is excellent in heat resistance, dimensional stability, adhesion, insulation, etc., and in particular, a flexible metal excellent in processability (solution moldability), flexibility, HAI (high current arc ignition) resistance, and moisture absorption characteristics. The present invention relates to a tension laminate, a flexible printed circuit board, a heat resistant resin composition used therefor, and an insulating film.

  In the present specification and claims, a “flexible metal-clad laminate” is a laminate formed from a metal foil and a resin layer, and is a laminate useful for the production of, for example, a flexible printed circuit board. . In addition, the “flexible printed circuit board” can be manufactured by a conventionally known method such as a subtractive method using a flexible metal-clad laminate, and a conductor circuit may be partially or fully covered by a cover as necessary. A so-called flexible circuit board (FPC), flat cable, circuit board for tape automated bonding (TAB), etc., which are covered with a film, screen printing ink, or the like are generically named.

  A conventional flexible metal-clad laminate for a flexible printed circuit board is obtained by bonding a polyimide film and a metal foil with an adhesive such as a rubber-modified epoxy resin or acrylic resin. The flexible printed circuit board formed from the flexible metal-clad laminate bonded with this adhesive is inferior in heat resistance such as solder heat resistance and thermal dimensional stability because the heat resistance of the adhesive is significantly inferior to that of the polyimide film. There was a problem.

In order to solve these problems, a technique for forming a metal-clad laminate (two-layer CCL) having a two-layer structure without an adhesive layer by directly applying a polyimide resin solution to a metal foil has been proposed. (For example, refer to Patent Documents 1 and 2). However, these two-layer CCL
(1) Since the polyimide resin to be applied is insoluble in an organic solvent, it is necessary to imidize by applying a polyamic acid solution, which is a precursor thereof, and then performing high-temperature heat treatment on the metal foil. Therefore, it is inferior to workability.
(2) Since the elastic modulus of the resin film layer formed on the metal foil is high, the flexible printed board is inferior in bending resistance.
There are disadvantages such as.

  In order to improve the processability and bending resistance as described above, in Patent Document 3, a resin composition that is soluble in an organic solvent and has a low film elastic modulus is directly applied to a metal foil and dried. A technique for forming a two-layer CCL has been proposed. However, although the resin composition used here is excellent in workability and bending resistance, it is inferior in resistance to HAI (high current arc ignition), so it is loaded with high voltage and large current as a flexible printed circuit board. There is a disadvantage that it is not suitable for a certain application. In addition, the resin film layer has a high moisture absorption rate and has a drawback that the yield in the processing process of the flexible printed wiring board is low.

On the other hand, a polyimide resin or the like has been conventionally used as an insulating film for a flexible printed board (a film for a coverlay or a film for a substrate). For example, Patent Document 4 describes a polyimide film used as an insulating film for a flexible printed circuit board.
However, these insulating films have a drawback in that the adhesion between them has not been good. In addition, in a flexible printed circuit board obtained by combining an insulating film, a metal foil, and an adhesive, the properties and performance of the insulating film, the properties and performance of the metal foil, and the properties and performances of the adhesive, respectively, In terms of performance, it is extremely difficult to predict the performance as a flexible printed circuit board. In the development of a flexible printed circuit board, will the required performance as a flexible printed circuit board be satisfied unless it is actually evaluated by combining various materials? There was a special situation where it was not possible to predict whether or not.

  For this reason, it has been extremely difficult for those skilled in the art to predict whether a general-purpose conventional adhesive can be used for a flexible printed circuit board. For example, in the case of a flexible printed wiring board composed of four layers of a base film layer, a metal foil layer, an adhesive layer, and an insulating film, the performance of the flexible printed wiring board is satisfied as the entire four layers. There was a need. If the adhesive force between the base film layer and the adhesive layer is not sufficient, the performance as a flexible printed circuit board cannot be satisfied, and the adhesive force between the metal foil layer and the adhesive layer is sufficient. Otherwise, the performance as a flexible printed circuit board cannot be satisfied, and when the adhesive force between the insulating film layer and the adhesive layer is not sufficient, the performance as a flexible printed circuit board cannot be satisfied. In addition, even if each of the four layers of material is a material having good performance, if there is a variation in physical properties between one of the four layers and the other layer, a flexible printed circuit board can be used. Can cause serious flaws.

  Therefore, in order to satisfy the required performance such as heat resistance, adhesiveness, and insulation required for flexible printed circuit boards, four layers (or when providing an adhesive layer between the base material layer and the metal foil layer) It is not enough to select a material with excellent performance for each of the five layers), and the interaction between the first layer material and the other layer material, the second layer material and the other layer material Interaction between the material of the third layer and the material of the other layer, the interaction of the material of the fourth layer and the material of the other layer, and in the case of the five layers, the material of the fifth layer All interactions with other layers of material need to be considered and designing an appropriate layer configuration has been extremely difficult for those skilled in the art.

  For example, in Patent Document 5, a polyester / polyurethane type adhesive is described, but it can be easily predicted by those skilled in the art whether such an adhesive can be used as an adhesive for a flexible pudding substrate. It wasn't.

  For this reason, for example, an NBR type adhesive as described in Patent Document 6 is used as an adhesive for a flexible print base. In this type of adhesive, in particular, a fine pattern is formed. In a flexible printed circuit board having a circuit, it has been difficult to ensure sufficient performance for various required qualities as a flexible printed circuit board.

JP-A-57-50670 JP-A-57-66690 JP 2001-105530 A JP 7-41588 A JP-A-11-116930 JP 2000-273430 A

The object of the present invention is to solve the above-mentioned problems, and in particular, a flexible metal-clad laminate for a flexible printed circuit board that can be used in applications where high reliability is required, and a flexible print. The substrate is to be manufactured at a low cost. That is, the first object of the present invention is excellent in workability (no imidization process on a metal foil, that is, no heat treatment at high temperature), flexibility, and HAI (high current arc ignition) resistance. A two-layer CCL, a two-layer flexible printed circuit board, and a resin and an insulating film used therefor are manufactured at low cost. The second object is to produce a flexible metal-clad laminate, a flexible printed circuit board, and a resin and insulating film used therefor, which are further excellent in moisture absorption characteristics, at low cost.
In addition to these characteristics, it also has various performances such as heat resistance, adhesiveness, dimensional stability, and insulation (migration properties, especially migration performance when the wiring thickness is narrow and the wiring spacing is narrow). An object of the present invention is to provide a flexible printed circuit board which is excellent and has an excellent balance of various performances.

  As a result of diligent research to achieve the above object, the present inventors have developed a heat-resistant resin film that simultaneously satisfies each of the properties of solvent solubility / HAI resistance / low elastic modulus / low hygroscopicity, which has never existed before. And as a result of earnestly examining the layer structure, processing method, etc. as a flexible printed circuit board including these materials, it has been achieved. That is, this invention is the following polyamide imide resin, a resin composition, an insulating film, a flexible metal-clad laminate using the same, and a flexible printed circuit board.

（Ｘは、酸素原子、ＣＯ、ＳＯ₂、又は、直結を示し、ｎは０又は１を示す。）

（Ｙは、酸素原子、ＣＯ、又はＯＯＣ−Ｒ−ＣＯＯを示し、ｎは０又は１を、Rは二価の有機基を示す。）

The first invention comprises at least one selected from the group consisting of general formula (1) and general formula (2), general formula (3) and general formula (4) as an essential component, and the copolymerization ratio thereof is { The general formula (1)} / {the general formula (2) + the general formula (3) + the general formula (4)} = 99/1 to 5/95 (molar ratio).

(X represents an oxygen atom, CO, SO ₂ , or direct connection, and n represents 0 or 1)

(Y represents an oxygen atom, CO, or OOC-R-COO, n represents 0 or 1, and R represents a divalent organic group.)

  The second invention comprises at least one selected from the group consisting of general formula (2) and general formula (3) and general formula (4) as an essential component, and the copolymerization ratio thereof is {general formula (2)} / {General formula (3) + General formula (4)} = 95 / 5-5 / 95 (molar ratio) polyamideimide resin.

  According to a third invention, in the general formula (2), the bond ratio of the ratio in which the amide bond is in the para position and the ratio in which the amide bond is in the meta position is para position / meta position = 5/95 to 100/0 mol%. The polyamide-imide resin according to the first or second invention.

（Ｘは、酸素原子、ＣＯ、ＳＯ₂、又は、直結を示し、ｎは０又は１を示す。） 4th invention is the polyamideimide resin as described in 1st or 2nd invention whose general formula (2) is General formula (5).

(X represents an oxygen atom, CO, SO ₂ , or direct connection, and n represents 0 or 1)

  A fifth invention is a polyamide-imide resin according to any one of the first to fourth inventions, which is non-halogen.

  A sixth invention is the polyamide-imide resin according to the fifth invention, which is soluble in an organic solvent.

  7th invention is a polyamide-imide resin as described in 6th invention whose HAI resistance is 15 times or more.

  An eighth invention is a polyamide-imide resin obtained by reacting a silicone compound with the polyamide-imide resin according to any one of the first to seventh inventions.

  A ninth invention is a polyamide-imide resin composition obtained by mixing a silicone compound with the polyamide-imide resin according to any one of the first to seventh inventions.

  A tenth invention is a polyamide-imide resin composition obtained by mixing silica with the polyamide-imide resin according to any one of the first to seventh inventions.

  An eleventh invention is the polyamide-imide resin composition according to the tenth invention, wherein the silica particle system is 1 nm to 10 μm.

  A twelfth invention is a polyamide obtained by blending the polyamideimide resin according to any one of the first to seventh inventions with a polyimide resin containing a biphenyl skeleton and / or a polyamideimide resin (including precursors thereof). Imide resin composition.

  A thirteenth aspect of the present invention is a polyamide imide resin containing 3,3′-dimethyl-4,4′-diaminobiphenyl as an essential component as an amine component in the polyamide imide resin according to any one of the first to seventh aspects of the invention. A polyamide-imide resin composition obtained by blending.

  In a fourteenth invention, the acid component of the polyamideimide resin containing 3,3′-dimethyl-4,4′-diaminobiphenyl as an essential component is trimellitic anhydride, benzophenonetetracarboxylic dianhydride, and biphenyltetracarboxylic acid. The polyamide-imide resin composition according to the thirteenth invention, comprising dianhydride as an essential component.

  The fifteenth invention is obtained by dissolving the polyamideimide resin described in any of the first to eighth inventions or the polyamideimide resin composition described in any of the ninth to fourteenth inventions in an organic solvent. varnish.

  In the sixteenth invention, the organic solvent is N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethyl It is at least one selected from the group consisting of sulfooxide, γ-butyrolactone, cyclohexanone and cyclopentanone, or a part of these is selected from the group consisting of toluene, xylene, diglyme, triglyme, tetrahydrofuran, methyl ethyl ketone and methyl isobutyl ketone. The varnish according to the fifteenth aspect, which is replaced with at least one selected from the above.

  A seventeenth invention is a film obtained from the polyamideimide resin according to any one of the first to eighth inventions or the polyamideimide resin composition according to any one of the ninth to fourteenth inventions.

  An eighteenth invention is a film in which an adhesive is laminated on at least one surface of the film according to the seventeenth invention.

According to a nineteenth aspect of the present invention, the adhesive contains an epoxy resin and a polyester urethane resin, the epoxy resin contains a novolac type epoxy resin and a bisphenol A type epoxy resin, and the polyester urethane resin comprises the following (1), The film according to the eighteenth invention that satisfies the conditions of (2), (3), and (4).
(1) The total content of terephthalic acid and isophthalic acid in 100 mol% of the acid component of the polyester component is 70 mol% to 100 mol%,
(2) the isocyanate component contains hexamethylene diisocyanate,
(3) Acid value is 100-1000 equivalent / 10 < ⁶ > g,
(4) The number average molecular weight is 8000 to 100,000.

  In a twentieth aspect, the metal foil is directly on at least one side of the polyamide-imide resin according to any one of the first to eighth aspects or the polyamide-imide resin composition according to any one of the ninth to fourteenth aspects. A flexible metal-clad laminate that is laminated or laminated via an adhesive layer.

  A twenty-first invention is a flexible printed circuit board obtained from the metal-clad laminate according to the twentieth invention.

  The 22nd invention is a flexible printed circuit board including a base film layer, a conductor layer, an adhesive layer, and a cover film layer, wherein the cover film layer is a polyamide-imide resin according to any one of the 1st to 8th inventions, Or the flexible printed circuit board which is the polyamide-imide resin composition as described in any one of 9th-14th invention.

  A twenty-third invention is a flexible printed board including a base film layer, a conductor layer, an adhesive layer, and a cover film layer, wherein the base film layer is the polyamide-imide resin according to any one of the first to eighth inventions. Or a polyamideimide resin composition according to any one of the ninth to fourteenth inventions.

24th invention contains the polyester urethane resin by which the adhesive bond layer was bridge | crosslinked with the epoxy resin, this epoxy resin contains a novolak type epoxy resin and / or a bisphenol A type epoxy resin, and this polyester urethane The flexible printed wiring board according to claim 22 or 23, wherein the resin satisfies the following conditions (1), (2), (3), and (4).
(1) The total content of terephthalic acid and isophthalic acid in 100 mol% of the acid component of the polyester component is 70 mol% to 100 mol%,
(2) the isocyanate component contains hexamethylene diisocyanate,
(3) Acid value is 100-1000 equivalent / 10 < ⁶ > g,
(4) The number average molecular weight is 8000 to 100,000.

  The flexible metal-clad laminate of the present invention is composed of a heat-resistant polyamide-imide resin that simultaneously satisfies the following properties: solvent solubility / HAI resistance / low elastic modulus / low hygroscopicity. Excellent adhesion, excellent HAI resistance, flexibility and moisture absorption. Furthermore, since the polyamideimide resin used is soluble in an organic solvent, it can be produced at low cost without the need for heat treatment at high temperatures. Therefore, since a flexible substrate that can be used even for printed wiring boards loaded with a high voltage or a large current can be manufactured at a low cost, there are significant industrial advantages. In addition, the flexible printed circuit board of the present invention is excellent in heat resistance, adhesiveness, dimensional stability, flexibility, insulation, etc. (migration resistance), and is excellent in the balance of these various performances from the prior art. This is an effect of the present invention that could not be easily achieved.

[Polyamideimide resin]
One preferred embodiment of the polyamide-imide resin used for achieving the object of the present invention comprises a unit represented by the general formula (1) as an essential component, and further includes the general formula (2), the general formula (3) and The molecular chain contains at least one unit selected from the group represented by formula (4) as a repeating unit. Here, in the general formula (2), X is preferably SO ₂ , direct connection (biphenyl), or n = 0, and more preferably direct connection (biphenyl), or n = 0. In general formula (3), Y is preferably CO or direct bond (biphenyl), particularly from the viewpoint of HAI resistance, in which the free rotation of the aromatic ring or imide ring is small and the entropy change in melting or dissolution is small. Further, the units represented by the following general formula (2) and general formula (3) may be one kind or two or more kinds, respectively. Note that a substituent may be bonded to the naphthalene skeleton or benzene skeleton which is an essential component.

  The content ratio of the general formula (1) and the general formula (2), the general formula (3), and the general formula (4) is {general formula (1)} / {general formula (2) + general formula ( 3) + general formula (4)} = 99/1 to 5/95, more preferably {general formula (1)} / {general formula (2) + general formula (3) + general formula (4)} = 90 / 10-50 / 50. When the content ratio exceeds 99/1, the HAI resistance (high current arc ignition property) is deteriorated, and the moisture absorption rate of the resin is increased, so that the moisture absorption characteristics tend to be deteriorated.

  HAI resistance, as described in the examples below, uses a stainless steel electrode and a copper electrode, generates an arc with a voltage of 240 V, a short-circuit current of 32.5 mm, and a power factor of 50% 40 times per minute. It measures the number of arcs until the material ignites, and is a characteristic that is required 15 times or more in printed wiring board applications where high voltage or large current is loaded.

  When the content ratio of the general formula (1) is less than 5 mol%, there are portions depending on the composition of the general formula (2), the general formula (3), and the general formula (4), but the resin dissolves in the organic solvent. When this resin is coated on copper foil and a two-layer CCL is molded, it must be molded in the form of a precursor and heat treatment at a high temperature is required. May be worse. Furthermore, since the elasticity modulus of a resin film becomes high, it exists in the tendency for the bending characteristic at the time of processing to a flexible printed circuit board to fall.

  As described above, the content ratio of the general formula (2), the general formula (3), and the general formula (4) is such that the copolymerization ratio with respect to the general formula (1) is within the above range. A satisfactory one is obtained. Here, the general formula (2), the general formula (3), and the general formula (4) may each be one type or two or more types, but the preferred molar ratio when using one type is the general formula (1) / General formula (2) = 99/1 to 80/20, General formula (1) / General formula (3) = 99/1 to 40/60, General formula (1) / General formula (4) = 99/1 80/20. When the content ratio of the general formula (1) exceeds the upper limit in each of these content ratios, the HAI resistance (high current arc ignition property) is deteriorated, and the moisture absorption rate of the resin is increased. There is a tendency for the characteristics to deteriorate. On the other hand, when the content of the general formula (1) is less than the lower limit, the solubility in a solvent is poor, and the elastic modulus of the resin film is increased, so that the bending resistance tends to be lowered. The deterioration of these properties, in particular, solubility and bending resistance are high in the general formula (2) in which the amide bond is in the para position with respect to each other, and in general formula (3), Y is a biphenyl bond or a carbonyl bond. This is remarkable when a composition excellent in the effect of improving HAI resistance such as (CO) is used. Even if the general formula (1) is 5 mol% or less, it is possible to find a combination of compositions satisfying the properties of HAI resistance / solubility / flexibility, but these individual performances and various performances In order to obtain a composition having an excellent balance, it is effective to introduce 5 mol% or more of the general formula (1) into the molecular chain.

  Furthermore, a particularly preferred embodiment from the viewpoint of HAI resistance and moisture absorption characteristics is a molar ratio of the content ratio of the amide-forming component of the general formula (2) and the imide-forming component of the general formula (3) and / or the general formula (4) It is preferable to adjust to {General Formula (2)} / {General Formula (3) + General Formula (4)} = 5/95 to 95/5. If the content of {general formula (2)} in general formula (2) and general formula (3) and / or general formula (4) is less than 5 mol%, the effect of improving moisture absorption is small, and 95 mol If it exceeds 50%, the effect of improving HAI resistance may be small. In one preferred embodiment, the general formula (1) is a repeating unit from trimellitic anhydride and 1,5-naphthalene diisocyanate, the general formula (2) is a repeating unit from terephthalic acid and 1,5-naphthalene diisocyanate, (3) is a repeating unit from biphenyltetracarboxylic dianhydride and 1,5-naphthalene diisocyanate, and the content ratio thereof is general formula (1) / {general formula (2) + general formula (3)} = 90 / It is 10-70 / 30 molar ratio, and is general formula (2) / general formula (3) = 10 / 90-90 / 10 molar ratio.

  In the above, when the content of {general formula (1)} in general formula (1), general formula (2) and general formula (3) exceeds 90 mol%, the HAI resistance and moisture absorption characteristics are deteriorated. In addition, if it is less than 70 mol%, the solvent solubility of the resin may be deteriorated and the film elastic modulus may be increased. In addition, when the content of {general formula (2)} in the general formulas (2) and (3) is less than 10 mol%, the moisture absorption characteristics are deteriorated. There is a possibility that the solvent solubility may deteriorate.

  In another preferred embodiment of the polyamideimide resin used for achieving the object of the present invention, the unit represented by the general formula (2) is an essential component, and further, the general formula (3) and the general formula (4) are used. In the molecular chain, at least one unit selected from the group represented by the formula is contained as a repeating unit, and the copolymerization ratio thereof is {general formula (2)} / {general formula (3) + general formula (4)} = polyamideimide resin in which 95/5 to 5/95 (molar ratio). A more preferable copolymerization ratio is {general formula (2)} / {general formula (3) + general formula (4)} = 80/20 to 20/80 (molar ratio), more preferably {general formula (2)} / {General formula (3) + General formula (4)} = 50/50 to 20/80 (molar ratio). {General formula (2)} / {general formula (3) + general formula (4)} = 95/5 or more, the moisture absorption rate of the resin is high, so the hygroscopic property tends to deteriorate, and the HAI resistance There is little improvement effect. Moreover, when {general formula (2)} / {general formula (3) + general formula (4)} = 5/95 or less, the solubility of the resin in an organic solvent tends to be deteriorated, and the resin is placed on a copper foil. When the two-layer CCL is molded by coating, it must be molded in the form of a precursor, and heat treatment at a high temperature is required, so that workability may be deteriorated. Furthermore, since the elasticity modulus of a resin film becomes high, it exists in the tendency for the bending characteristic at the time of processing to a flexible printed circuit board to fall.

Here, in the general formula (2), X is preferably SO ₂ , direct connection (biphenyl), or n = 0, and more preferably direct connection (biphenyl), or n = 0. In the general formula (3), Y is particularly preferably CO or direct bond (biphenyl), which has less free rotation of the aromatic ring or imide ring and has little entropy change of melting or dissolution, from the viewpoint of HAI resistance. Further, the units represented by the following general formula (2) and general formula (3) may be one kind or two or more kinds, respectively. Note that a substituent may be bonded to the naphthalene skeleton or benzene skeleton which is an essential component.

  In the above, one preferred embodiment is that the general formula (2) is a repeating unit from terephthalic acid and 1,5-naphthalene diisocyanate, and the general formula (3) is biphenyltetracarboxylic dianhydride and / or benzophenonetetracarboxylic acid dicarboxylic acid. Repeating unit from anhydride and 1,5-naphthalene diisocyanate, general formula (4) is a repeating unit from pyromellitic anhydride and 1,5-naphthalene diisocyanate, the content ratio of which is general formula (2) / {general Formula (3) + general formula (4)} = 5/95 to 40/60 molar ratio. If the content of {general formula (2)} in general formula (2) and general formula (3) and / or general formula (4) exceeds 40 mol%, the HAI resistance and moisture absorption characteristics will decrease. In addition, if it is less than 5 mol%, the solvent solubility of the resin may be deteriorated.

In both embodiments, a preferred common aspect will be described. In the general formula (2), it is particularly preferable that the bond ratio of the ratio in which the amide bond is in the para position and the ratio in the meta position satisfies the para position / meta position = 5/95 to 100/0 mol%. More preferably, the bond ratio of the ratio in which the amide bond is in the para position and the ratio in the meta position satisfies the para position / meta position = 20/80 to 100/0 mol%, and most preferably the para position. / Meta position = when satisfying 50/50 to 100/0 mol%. When the para position is 5 mol% or less, the effect of improving the HAI resistance (high current arc ignition resistance) tends to decrease. In particular, the polyamideimide resin in which the general formula (2) is the general formula (5) exhibits excellent characteristics in terms of HAI resistance (high current arc ignition resistance). Further, in the general formula (5), X is preferably SO ₂ , direct connection (biphenyl), or n = 0, more preferably direct connection (biphenyl), or n = 0.

  Further, these polyamide-imide resins are preferably non-halogen-based resins that do not contain halogens such as fluorine, chlorine, bromine, and iodine from the viewpoint of environmental considerations.

  Furthermore, it is desirable that these polyamideimide resins can be dissolved in an organic solvent in consideration of workability when a flexible metal-clad laminate or a laminated film with an adhesive layer, which will be described later, is taken into consideration. The organic solvents mentioned here are N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethylsulfone. It is at least one selected from the group consisting of oxide, γ-butyrolactone, cyclohexanone and cyclopentanone, or a part thereof is selected from the group consisting of toluene, xylene, diglyme, triglyme, tetrahydrofuran, methyl ethyl ketone and methyl isobutyl ketone. Replaced with at least one of the above. In the present invention, being soluble in an organic solvent means 10% by weight or more dissolved in any one of the above-mentioned single solvents or a mixed organic solvent containing 20% or more of at least one of them. To do. Preferably, it is 15% by weight or more, more preferably 20% by weight or more. In addition, when the resin is in a solid state, whether or not it has been dissolved is determined by adding a specified weight of resin powder passing through 80 mesh into a 200 ml beaker and gently stirring at 25 ° C. for 24 hours. It was determined that it was dissolved at 25 ° C. for 24 hours, and the solution that was not gelled, non-uniformized, clouded, or precipitated was dissolved.

In order to be soluble in a solvent, (1) the above-mentioned preferred resin composition is made (2) the ratio of imide group / amide group is lowered (3) polycarboxylic acid component and polyamine component having an alicyclic group described later (4) A polycarboxylic acid component having an aliphatic group, which will be described later, and a copolymerized as a polyamine component (5) A flexible group is introduced into the aromatic ring.
(6) A bulky compound is introduced into the polymer chain.
(7) The polymer is modified with an epoxy compound described later.
Etc. can be achieved.

  As described above, with the naphthalene skeleton as the main skeleton and the bond ratio set to a specific ratio, the rigidity / flexibility of the polymer chain itself, the intermolecular force between the polymer chains, the plane orientation, etc. are well balanced. In addition, the HAI resistance and the low hygroscopicity can be expressed while maintaining the properties of solvent solubility and low elastic modulus.

[Production of polyamide-imide resin]
The polyamide-imide resin of the present invention can be synthesized by a usual method. For example, the isocyanate method, the amine method (acid chloride method, low temperature solution polymerization method, room temperature solution polymerization method, etc.), etc., but since the polyamideimide resin used in the present invention is preferably soluble in an organic solvent, it is industrially used. Is preferably an isocyanate method in which the solution at the time of polymerization can be applied as it is.

  In the case of the isocyanate method, the resin composition used in the present invention by reacting the aromatic diisocyanate with trimellitic anhydride, aromatic dicarboxylic acid, aromatic tetracarboxylic dianhydride, etc. as raw materials in an organic solvent in an approximately stoichiometric amount. You can get things. Here, as the aromatic tetracarboxylic acid anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, diphenyl ether-3,3 ′, 4,4′-tetracarboxylic Acid, ethylene glycol bisanhydro trimellitate, etc., aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, etc., and aromatic diisocyanate as 1,4- Naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 2,7-naphthalene diisocyanate and the like can be used. From the balance of HAI resistance / flexibility / moisture absorption properties, the preferred combination of raw materials is as aromatic tetracarboxylic anhydride, benzophenone tetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride is aromatic diisocyanate As 1,5-naphthalene diisocyanate. As the aromatic dicarboxylic acid, terephthalic acid and biphenyl dicarboxylic acid are preferable.

  The reaction is preferably carried out in an organic solvent usually at 10 ° C. to 200 ° C. for 1 hour to 24 hours, and the reaction is a catalyst for the reaction of an isocyanate and an active hydrogen compound, for example, tertiary amines, alkali metal compounds, alkaline earth metals You may carry out in presence of a compound etc.

  Further, in the case of the amine method, the present invention is obtained by reacting trimellitic anhydride chloride, aromatic dicarboxylic acid chloride, aromatic tetracarboxylic dianhydride, and aromatic diamine as raw materials in an organic solvent in a substantially stoichiometric reaction. A polyamide-imide resin used in the above can be obtained. Here, as the aromatic tetracarboxylic acid anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, diphenyl ether-3,3 ′, 4,4′-tetracarboxylic Acids, ethylene glycol bisanhydro trimellitate, etc., and aromatic dicarboxylic acid chlorides include terephthalic acid chloride, isophthalic acid chloride, biphenyl dicarboxylic acid chloride, diphenyl ether dicarboxylic acid chloride, diphenyl sulfone dicarboxylic acid chloride, etc., aromatic diamine 1,4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine and the like can be used. The reaction is preferably performed in an organic solvent at 0 to 100 ° C. for about 1 to 24 hours. A preferable combination of raw materials is the same as in the isocyanate method.

  As a polymerization solvent for producing the polyamideimide resin of the present invention, an organic solvent capable of dissolving the polyamideimide resin can be used. Typical examples of such organic solvents include, for example, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane. Dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, cyclopentanone, etc., preferably N-methyl-2-pyrrolidone. Some of these can be replaced with 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.

  The molecular weight of the polyamideimide resin of the present invention is the molecular weight corresponding to 0.3 to 2.5 dl / g in N-methyl-2-pyrrolidone (polymer concentration 0.5 g / dl) and logarithmic viscosity at 30 ° C. Those having a molecular weight corresponding to 0.5 to 2.0 dl / g are more preferable. If the logarithmic viscosity is 0.3 dl / g or less, the mechanical properties may be insufficient when formed into a molded product such as a film, and if the log viscosity is 2.0 dl / g or more, the solution viscosity becomes high. It can be difficult.

  The polyamide-imide resin of the present invention has the characteristics intended by the present invention for the purpose of balancing various performances such as heat resistance, adhesiveness, dimensional stability, flexibility, insulation properties (migration resistance), moisture absorption characteristics, etc. In addition to the acid component, isocyanate component or amine component shown above, it is possible to copolymerize the acid component and amine component shown below. Also, a resin separately polymerized by a combination of these acid component and amine component can be mixed and used. Of course, the resins polymerized separately in combination of the above-mentioned acid component and amine component may be mixed together. In addition to the above-mentioned acid component, in addition to the acid component described below and the above-described amine component, described below A separately polymerized resin may be mixed in combination with the amine component.

Examples of the acid component include the following.
a) Tricarboxylic acid; diphenyl ether-3,3 ′, 4′-tricarboxylic acid, diphenylsulfone-3,3 ′, 4′-tricarboxylic acid, benzophenone-3,3 ′, 4′-tricarboxylic acid, naphthalene-1,2 , 4-tricarboxylic acid, monoanhydrides such as tricarboxylic acid such as butane-1,2,4-tricarboxylic acid, esterified compounds, or a mixture of two or more.
b) Tetracarboxylic acid; diphenylsulfone-3,3 ′, 4,4′-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid , Naphthalene-1,4,5,8-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid monoanhydride, dianhydride , Esterified product alone or a mixture of two or more.
c) Dicarboxylic acid; adipic acid, azelaic acid, sebacic acid, dicarboxylic acid of cyclohexane-4,4′-dicarboxylic acid, and monoanhydrides and esterified products thereof.

Examples of the amine component include the following.
d) Amine component 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2 , 2′-diethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-diethoxy-4,4′-diaminobiphenyl, p-phenylenediamine, m -Phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminobiphenyl, 3,3 ' -Diaminobiphenyl, 3,3'-diaminobenzanilide, 4,4'-diaminobenzanilide, 4,4'-diaminobenzophenone, 3,3'-diamy Nobenzophenone, 3,4'-diaminobenzophenone, 2,6-tolylenediamine, 2,4-tolylenediamine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4 ' -Diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, p-xylenediamine, m-xylenediamine, 2,2'-bis (4-amino) Phenyl) propane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4 -(4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] propane, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3 -Aminophenoxy) biphenyl, tetramethylenediamine, hexamethylenediamine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, cyclohexane-1,4-diamine, diaminosiloxane, or the corresponding diisocyanate alone or in two kinds The above mixture is mentioned.

  In particular, surprisingly, by blending the polyamideimide resin of the present invention with a polyimide resin and / or polyamideimide resin containing a biphenyl skeleton, heat resistance, adhesion, dimensional stability, flexibility, insulation (resistance resistance) This is effective not only for balancing various performances such as migration properties) and moisture absorption characteristics, but also for improving HAI resistance depending on the blending ratio. The biphenyl skeleton is preferably copolymerized by 50 mol% or more of the carboxylic acid component and / or the amine component. Preferably 70 mol% or more is copolymerized. The resin containing a biphenyl skeleton is preferably a polyamide-imide resin containing 3,3′-dimethyl-4,4′-diaminobiphenyl as an essential component as an amine component, and more preferably, as shown in the examples below, 3 Polyamideimide resin containing 3,3'-dimethyl-4,4'-diaminobiphenyl as an amine component and trimellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride as an essential component of the acid component It is.

  A preferable amount to be blended is 5% to 70% by weight, preferably 10% to 50% by weight in terms of solid content (weight ratio) when the total amount of polyamideimide (polyimide) resin is 100% by weight. More preferably, it is 20 to 40% by weight. Below 5% by weight, there is little effect in balancing various performances as a flexible printed circuit board, such as heat resistance, adhesiveness, dimensional stability, flexibility, insulation (migration resistance), moisture absorption characteristics, etc., and HAI resistance There is little improvement effect. On the other hand, if it is 70% by weight or more, the HAI resistance tends to decrease. As a matter of course, in terms of HAI resistance itself, a resin having a naphthalene skeleton, which is a heat resistant resin of the present invention, is remarkably superior to the above-described resins having a biphenyl skeleton. The effect of these blends, particularly the effect of improving HAI resistance, is that the polymer chain having a naphthalene skeleton and the polymer chain having a biphenyl skeleton are entangled with each other while forming a physical crosslinking point and the like, thereby forming a bulk film. It is thought that sometimes a specific layer structure similar to the IPN structure is formed.

  In addition, polyimide resins and / or polyamideimide resins containing a biphenyl skeleton to be blended with the above polyamideimide resin may be heat resistant, adhesive, dimensional stability, bending even with polyamic acid resin, which is a precursor of polyimide or polyamideimide. It is effective in balancing various performances as a flexible printed circuit board, such as properties, insulation (migration resistance), and moisture absorption characteristics, and in improving HAI resistance. When a polyamic acid resin is blended, an imidization step is required at the time of molding a flexible metal-clad laminate or film, but in the present invention, dehydration in a polyamide-imide resin (especially effective in the case of thermoplasticity) Since it becomes a polyimidation reaction, imidization under relatively mild conditions is possible as shown in the examples described later. For this reason, the resin composition which does not impair the workability (polyimide-ization at a comparatively low temperature) which is one feature of the present invention can be obtained. As a polyamic acid resin which is a precursor of polyimide, or a ring-closed body (polyimide) thereof, a polyimide containing a biphenyl skeleton synthesized by a combination of an acid component and an amine component shown below and / or a polyamic acid is preferable.

Examples of the acid component and amine component that can be used for the polyimide resin and / or the polyamide-imide resin containing the biphenyl skeleton to be blended with the polyamide-imide resin are shown below.
Acid component; trimellitic anhydride, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid, diphenylethertetracarboxylic acid, naphthalenetetracarboxylic acid monoanhydride, dianhydride, esterified product, etc., alone or a mixture of two or more.
Amine component; 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2, 2'-diethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-diethoxy-4,4'-diaminobiphenyl, p-phenylenediamine, m- Phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminobiphenyl, 3,3'- Diaminobiphenyl, 3,3′-diaminobenzanilide, 4,4′-diaminobenzanilide, 4,4′-diaminobenzophenone, 3,3′-diamino Benzophenone, 3,4'-diaminobenzophenone, 2,6-tolylenediamine, 2,4-tolylenediamine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4 ' -Diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, p-xylenediamine, m-xylenediamine, 1,4-naphthalenediamine, 1,5 -Naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2'-bis (4-aminophenyl) propane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2 Bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-amino Phenoxy) phenyl] propane, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, tetramethylenediamine, hexamethylenediamine, isophoronediamine, 4,4′- Dicyclohexylmethanediamine, cyclohexane-1,4-diamine, diaminosiloxane, or the corresponding diisocyanate alone or a mixture of two or more.

Among the acid component and amine component, particularly preferred combinations are as follows.
Acid component; biphenyl tetracarboxylic acid, diphenyl ether tetracarboxylic acid monoanhydride, dianhydride, esterified product or the like alone or a mixture of two or more.
Amine component; 3,3′-dimethyl-4,4′-diaminobiphenyl, p-phenylenediamine, m-phenylenediamine, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,4′-diamino Biphenyl, 3,3′-diaminobiphenyl, 3,3′-diaminobenzanilide, 4,4′-diaminobenzanilide, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-amino) Phenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-bis (4-aminophenoxy) biphenyl, 4 , 4′-bis (3-aminophenoxy) biphenyl, or the corresponding diisocyanate alone, or two or more mixture.

Among the acid component and amine component, the most preferred combinations are as follows.
Acid component; trimellitic anhydride, benzophenonetetracarboxylic dianhydride and biphenyltetracarboxylic dianhydride.
Amine component; 3,3′-dimethyl-4,4′-diaminobiphenyl, p-phenylenedimine.
In particular, biphenyltetracarboxylic anhydride / benzophenonetetracarboxylic dianhydride) = 1/99 to 99/1 molar ratio, preferably biphenyltetracarboxylic anhydride / benzophenonetetracarboxylic dianhydride = 30/70 to 70/30 molar ratio and {biphenyltetracarboxylic anhydride + benzophenonetetracarboxylic dianhydride} / trimellitic anhydride = 30 / 70-1 / 99 molar ratio, preferably {biphenyltetracarboxylic anhydride Product + benzophenonetetracarboxylic dianhydride} / trimellitic anhydride = 20/80 to 5/95 molar ratio. Further, 3,3′-dimethyl-4,4′-diaminobiphenyl is preferably a polyamide-imide resin copolymerized by 50 mol% or more, preferably 80 mol% or more.

  The molecular weight of polyamic acid resin, which is a precursor of polyimide or polyamideimide, or a ring-closed product thereof (polyimide, polyamideimide) is logarithm at 30 ° C. in N-methyl-2-pyrrolidone (polymer concentration 0.5 g / dl). Those having a molecular weight corresponding to 0.3 to 5.0 dl / g in terms of viscosity are preferred, more preferably those having a molecular weight corresponding to 0.8 to 2.5 dl / g. When the logarithmic viscosity is 0.3 dl / g or less, mechanical properties may be insufficient when formed into a molded product such as a film. On the other hand, when the logarithmic viscosity is 5.0 dl / g or more, compatibility with a polyamide-imide resin or molding processing may occur. May be difficult.

[Polyamideimide resin solution]
If necessary, the polyamide-imide resin solution of the present invention may be used for the purpose of improving various properties of the flexible metal-clad laminate or flexible printed circuit board, such as mechanical properties, electrical properties, slipperiness, and flame retardancy. Other resins, organic compounds, and inorganic compounds may be mixed or reacted to be used in combination. For example, lubricant (silica, talc, silicone, etc.), adhesion promoter, flame retardant (phosphorus, triazine, aluminum hydroxide, etc.), stabilizer (antioxidant, ultraviolet absorber, polymerization inhibitor, etc.), plating activity Agents, organic and inorganic fillers (talc, titanium oxide, silica, fluorine polymer fine particles, pigments, dyes, calcium carbide, etc.), silicone compounds, fluorine compounds, isocyanate compounds, blocked isocyanate compounds, acrylic resins, urethanes Resin, polyester resin, polyamide resin, epoxy resin, resin such as phenol resin and organic compounds, or these curing agents, inorganic compounds such as silicon oxide, titanium oxide, calcium carbonate, iron oxide, etc. do not hinder the purpose of this invention Can be used together in a range. If necessary, a catalyst for polyimide formation such as aliphatic tertiary amine, aromatic tertiary amine, heterocyclic tertiary amine, aliphatic acid anhydride, aromatic acid anhydride, hydroxy compound, etc. It may be added. For example, triethylamine, triethylenediamine, dimethylaniline, pyridine, picoline, isoquinoline, imidazole, undecene, hydroxyacetophenone and the like are preferable, and pyridine compound, imidazole compound and undecene compound are particularly preferable. Among them, benzimidazole, triazole, 4 -Pyridinemethanol, 2-hydroxypyridine and diazabicyclo [5.4.0] undecene-7 are preferred, and 2-hydroxypyridine and diazabicyclo [5.4.0] undecene-7 are more preferred.

  In particular, by mixing or reacting the polyamideimide resin with a silicone compound (silica or the like) or a silicone resin (silicon resin) compound, the HAI resistance is further improved. Examples of silicone compounds used include so-called silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane, silicone oil, silicone rubber, silicone varnish (Shin-Etsu Chemical). (Such as KR272 manufactured by KK) and intermediates thereof (KR9218 manufactured by Shin-Etsu Chemical Co., Ltd., ES1002T, etc.) are preferred. Silazane compounds such as hexamethyldisilazane, trimethylsilylimidazole, and dimethyltrimethylsilylamine (TSL8802, TSL883, TSl8834, etc. manufactured by Toshiba Silicone Co., Ltd.) also have the same effects as described above.

  Moreover, as silica to be used, those having various shapes such as spheres and scales can be used, and the particle diameter thereof is 1 nm to 10 μm, preferably 5 nm to 1 μm, more preferably 10 nm to 100 nm. When the particle diameter is 1 nm or less, the effect of improving the HAI resistance is small, and when it is 10 μm or more, the compatibility with the polyamideimide resin is deteriorated and the mechanical properties of the film tend to be lowered. Particularly preferable silica is DMAC-ST (particle diameter 20 nm) manufactured by Nissan Chemical Co., Ltd., XBA-ST (particle diameter 30 n), or Nanotech (particle diameter 25 nm) manufactured by CI Kasei Co., Ltd.

  The amount to be mixed or reacted is 0.01% to 20% by weight, preferably about 0.1% to 3% by weight with respect to 100% by weight of the polyamideimide resin. The effect of improving the HAI resistance is small, and if it is 20% by weight or more, the compatibility with the polyamideimide resin is deteriorated, and the mechanical properties and heat resistance of the film are lowered. Here, when the silicone resin is reacted, the amount of the silicone resin compound is mixed with the polyamideimide resin solution, and then heated and stirred at a temperature of 50 to 200 ° C. for 1 to 10 hours.

  Even if the resin composition to be mixed or blended is changed, the effect of improving the HAI resistance is manifested to some extent by changing the mixing or reaction amount of the silicone resin in the case of a polyamideimide resin system. In this case, as the polyamide-imide resin, any acid component, amine component, or isocyanate component exemplified in the present specification may be used as long as it is manufactured by the manufacturing method described in the present specification. In order to satisfy the final heat resistance / dimensional stability / adhesiveness / workability (solvent solubility) / low elastic modulus / HAI resistance / moisture absorption characteristics of the present application, the general formula (1 ), A polyamideimide resin having at least one repeating unit of the general formula (2), the general formula (3) and the general formula (4) as an essential component, or the general formula (2) and the general formula (3) And / or a polyamideimide resin having at least one repeating unit of the general formula (4) as an essential component is suitable.

  The concentration of the polyamideimide resin in the polyamideimide resin solution thus obtained can be selected from a wide range, but is generally about 5 to 40% by weight, and preferably about 8 to 20% by weight. When the concentration is out of the above range, the coatability tends to be lowered. Preferred solvents for the polyamide-imide resin solution include N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, and dimethylsulfo because of coating properties and the like. Among them, oxide, γ-butyrolactone, cyclohexanone, cyclopentanone, etc., particularly preferably N-methyl-2-pyrrolidone. Some of these can be replaced with 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. In addition, since these solvents can also be applied as solvents during polymerization, the polymerization solution can be applied as it is, so that a resin solution having excellent processability can be easily obtained.

  As an appropriate solution viscosity, the B-type viscosity at 25 ° C. is in the range of 1 to 1000 poise. When the viscosity is out of the above range, the coatability may be lowered.

[Heat resistant film]
A film can be produced using the above polyamideimide resin or resin composition. The polyamide-imide resin film is coated with a solution of the polyamide-imide resin on a support such as an endless belt, a drum, or a carrier film, and the coating film is dried. It is formed by.

(Dry)
In the present invention, there are no particular limitations on the drying conditions after coating, but generally, after initial drying at a temperature 70 ° C. to 130 ° C. lower than the boiling point (Tb (° C.)) of the solvent used in the polyamideimide resin solution, It is preferable to further dry (secondary drying) at a temperature near the boiling point of the solvent or at a temperature equal to or higher than the boiling point.
When the initial drying temperature is higher than (Tb-70) ° C., foaming occurs on the coated surface, and when the drying temperature is lower than (Tb-130) ° C., the drying time becomes longer and the productivity may be lowered. . The initial drying temperature varies depending on the type of solvent, but is generally about 60 to 150 ° C, preferably about 80 to 120 ° C. The time required for the initial drying is generally an effective time for the solvent remaining rate in the coating film to be about 5 to 40% under the above temperature conditions, but generally about 1 to 30 minutes, especially 2 ~ 15 minutes.

  The heat treatment conditions are not particularly limited, and may be dried at a temperature near the boiling point of the solvent or at a temperature equal to or higher than the boiling point, but is generally 120 ° C to 500 ° C, preferably 200 ° C to 400 ° C. When the temperature is 120 ° C. or lower, the drying time becomes longer and the productivity is lowered. When the temperature is 500 ° C. or higher, the deterioration reaction may progress depending on the resin composition, and the resin film may become brittle. The time required for the heat treatment may be an effective time that generally eliminates the solvent remaining rate in the coating film under the above temperature conditions, but is generally about several minutes to several tens of hours. Usually, the heat treatment is performed by drying a certain amount of solvent in the initial drying to form a self-supporting film, and then peeling off from the support, and fixing the end of the self-supporting film to a pin or the like. The method of performing is preferable.

In the present invention, drying and heat treatment may be performed under an inert gas atmosphere or under reduced pressure. Examples of the inert gas include nitrogen, carbon dioxide, helium, and argon, but it is preferable to use easily available nitrogen. Moreover, when it carries out under reduced pressure, it is preferable to carry out under the pressure of about 10 < ^-5 > -10 < ³ > Pa, preferably about 10 < ^-1 > -200 Pa.
The heat-resistant film of the present invention thus obtained is characterized by excellent heat resistance, dimensional stability, adhesiveness, and insulation (migration resistance). In addition, imidization process is not required and molding is possible only by drying solvent, or because heat treatment at high temperature is unnecessary, it can be manufactured at low cost and has excellent HAI resistance, flexibility and moisture absorption characteristics. It is characterized by that.

  In the case of preparing the flexible metal-clad laminate of the present invention comprising a polyamideimide resin film layer and a metal foil, which will be described later, the thickness of the polyamideimide resin film layer can be selected from a wide range. The later thickness is about 5 to 100 μm, preferably about 10 to 50 μm. When the thickness is less than 5 μm, the mechanical properties such as film strength and handling properties are inferior. On the other hand, when the thickness exceeds 100 μm, the properties such as flexibility and workability (drying property, coating property) are deteriorated. Tend to. In the case of a cover film to be described later, the thickness after drying is generally about 5 to 100 μm, preferably about 10 to 50 μm, and may be subjected to a surface treatment if necessary. For example, surface treatment such as hydrolysis, corona discharge, low temperature plasma, physical roughening, and easy adhesion coating treatment can be performed.

[Heat resistant film laminated with adhesive]
By providing an adhesive layer on the heat resistant film, it can be used as an adhesive film. Although the use of this heat resistant film with an adhesive layer is not particularly limited, it exhibits excellent characteristics when used as a cover film or a base film of a flexible printed board described later. As the adhesive layer, a composition containing an epoxy resin and a polyester polyurethane resin is preferable. Here, the epoxy resin is preferably a composition containing a novolac type epoxy resin and a bisphenol A type epoxy resin.
Here, the polyester polyurethane resin is preferably a composition that satisfies the following conditions (1), (2), (3), and (4) before being crosslinked with the epoxy resin;
(1) Among the acid components of the polyester component, the total content of terephthalic acid and isophthalic acid is 70 mol% to 100 mol%,
(2) the isocyanate component contains hexamethylene diisocyanate,
(3) Acid value is 100-1000 equivalent / 10 < ⁶ > g,
(4) The number average molecular weight is 8000 to 100,000.

(Acid component)
In the above, terephthalic acid or isophthalic acid is used as the acid component of the polyester component of the polyester polyurethane resin. Either terephthalic acid or isophthalic acid may be used alone, or both terephthalic acid and isophthalic acid may be used.
The acid component of the polyester component of the polyester urethane resin preferably has a total content of terephthalic acid and isophthalic acid of 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 It is at least mol%, particularly preferably 100 mol%. When the blending amount of terephthalic acid and isophthalic acid is too small, the heat resistance tends to decrease.
As the dibasic acid component of the polyester polyol, in addition to terephthalic acid and isophthalic acid, various known dibasic acids can be used in combination as required. For example, the following dibasic acids can be used:
Aromatic dibasic acids such as orthophthalic acid, 1,5-naphthalic acid, 2,6-naphthalic acid, 4,4′-diphenyldicarboxylic acid, 2,2′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid , Adipic acid, sebacic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, dimer acid, etc. Aliphatic and alicyclic dibasic acids.
Aromatic dibasic acids are preferred in terms of heat resistance. Moreover, in order to balance adhesiveness and heat resistance, it is also preferable to use an aliphatic dibasic acid. In particular, orthophthalic acid, 2,6-naphthalic acid, and adipic acid are preferable.

(Glycol component)
Any glycol can be used as the glycol component of the polyester polyol. For example, the following glycols can be used. ;
Ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentane Diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, cyclohexanemethanol, neo Pentylhydroxypiparic acid ester, ethylene oxide adduct and propylene oxide adduct of bisphenol A, ethylene oxide adduct and propylene oxide adduct of water-added bisphenol A, 1,9-nonanediol, 2-methyloctanediol, , 10-dodecane diol, 2-butyl-2-ethyl-1,3-propanediol, tricyclodecane methanol.
Of the above glycols, ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, diethylene glycol, neopentyl glycol, and cyclohexanedimethanol are preferred.
It is also preferable to use polyether polyol as glycol. Specific examples include polyethers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

(Isocyanate)
The isocyanate component of the polyurethane component of the polyester polyurethane resin preferably contains 1,6-hexamethylene diisocyanate (hereinafter simply referred to as “hexamethylene diisocyanate”). Of 100 mol% of the isocyanate component, hexamethylene diisocyanate is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and 90 mol% or more. More preferably, it is particularly preferably 95 mol% or more, particularly preferably 100 mol% or more. If the amount of hexamethylene diisocyanate is too small, the adhesiveness is likely to be lowered.
As the organic diisocyanate component of the polyester polyurethane resin, any known isocyanate can be used in combination with hexamethylene diisocyanate, if necessary. Specifically, the following isocyanate is mentioned, for example. :
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, tetramethylene diisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate, 1, 5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 3,3′-dimethyl-4,4′-diisocyanate, 4,4′-diisocyanate diphenyl ether, 1,6-xylylene diisocyanate, 1,3-diisocyanate methylcyclohexane, 1,4-diisocyanate methylcyclohexane, 4,4′-diisocyanate methylcyclohexane, 4,4′-diisocyanate methylcyclohexylmethane, isophorone diisocyanate Nate.

(Acid value)
The acid value of the polyester polyurethane resin is preferably 100 to 1000 equivalents / 10 ⁶ g. The acid value is preferably 200 equivalents / 10 ⁶ g or more, particularly preferably 300 equivalents / 10 ⁶ g or more, more preferably 400 equivalents / 10 ⁶ g or more, and particularly preferably 500 equivalents. / 10 ⁶ g or more. Moreover, Preferably it is 900 equivalent / 10 < ⁶ > g or less, More preferably, it is 800 equivalent / 10 < ⁶ > g or less, More preferably, it is 700 equivalent / 10 < ⁶ > g or less. When the acid value is too large, the storage stability of the semi-finished product is likely to be lowered, and the water resistance and alkali resistance of the resin are likely to be lowered. If the acid value is too small, the heat resistance tends to decrease.
The acid value of the polyester polyurethane resin can be adjusted by, for example, a method of introducing a carboxyl group into the polyester polyurethane resin.
Specific examples of such a method include a method using a high molecular weight polyol having a carboxyl group as a raw material, and a method of binding a carboxyl group-containing diol compound such as dimethylolpropionic acid or dimethylolbutanoic acid to a resin. The specific method of the former is preferably a method of synthesizing a polyester diol and then subjecting the resulting diol to an addition reaction with a carboxylic acid anhydride compound or a method of depolymerizing with a carboxylic acid compound.

(Number average molecular weight)
The number average molecular weight of the polyester polyurethane resin is preferably 8000 to 100,000. Preferably it is 10,000 or more, More preferably, it is 12000 or more, More preferably, it is 14000 or more. Moreover, it is preferably 80000 or less, more preferably 60000 or less, further preferably 40000 or less, and particularly preferably 20000 or less. When the number average molecular weight is too large, it becomes difficult to synthesize the resin, and the viscosity is increased and the handleability of the resin is likely to be lowered. When the number average molecular weight is too small, the bending resistance tends to be lowered.
In the molecular weight distribution of the polyester polyurethane resin, the ratio of the molecular weight of 5000 or less is preferably 20% by weight or less. When the proportion of the molecular weight is 5000 or less, the curing reaction tends to proceed even at room temperature, and during storage, it is necessary to store at a low temperature or in a short period of time, and the heat resistance after curing tends to decrease.

The number average molecular weight of the polyester polyol used as a raw material for the polyester polyurethane resin is preferably 1000 or more, more preferably 3000 or more, still more preferably 7000 or more, and particularly preferably 10,000 or more. preferable. Moreover, it is preferable that it is 80000 or less, and it is more preferable that it is 50000 or less.
In the polyester polyurethane resin, the proportion of the polyester component, that is, the polyester polyol is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 60% by weight or more, 70 More preferably, it is more than 75 weight%, and it is especially preferable that it is 75 weight% or more. Moreover, it is preferable that it is 95 weight% or less, and it is more preferable that it is 90 weight% or less. When the amount of polyester polyol is too small, the heat resistance tends to decrease, and conversely, when too large, the adhesiveness tends to decrease.

  Therefore, regarding the ratio between the number average molecular weight of the polyester polyurethane resin and the number average molecular weight of the polyester polyol, it is preferable that the number average molecular weight of the polyester polyurethane resin is 100% and the number average molecular weight of the polyester polyol is 20% or more. More preferably, it is 40% or more, more preferably 60% or more, and even more preferably 70% or more. It is particularly preferably 75% or more. Moreover, it is preferable that it is 95% or less, and it is more preferable that it is 90% or less.

(Epoxy resin)
In the above adhesive, the polyester polyurethane resin is cross-linked using an epoxy resin. Here, as the epoxy resin, it is preferable to use a novolac type epoxy resin and a bisphenol A type epoxy resin in combination.
About the compounding quantity of an epoxy resin, it is preferable to mix | blend so that the equivalent ratio of the sum total of the carboxyl group in a polyurethane and the glycidyl group in all the epoxy resins may be set to 1: 0.5-1: 5, More preferably One to one to one to three. When the amount of epoxy resin is too small, the amount of unreacted epoxy resin remaining in the final product of the flexible printed board tends to increase, and the remaining unreacted epoxy resin may reduce performance such as heat resistance.

Examples of novolak type epoxy resins include phenol novolak glycidyl ether, cresol novolac glycidyl ether, brominated phenol novolac glycidyl ether, and brominated cresol novolak glycidyl ether. A brominated novolac type epoxy resin is preferably used in terms of flame retardancy.

  The epoxy equivalent of the novolac type epoxy resin is preferably 100 or more, more preferably 150 or more. Moreover, Preferably it is 700 or less, More preferably, it is 400 or less.

  The compounding amount of the novolac type epoxy resin is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, further preferably 20 parts by weight or more with respect to 100 parts by weight of the solid content of the polyester urethane resin. Yes, particularly preferably 25 parts by weight or more. Moreover, it is preferably 70 parts by weight or less, more preferably 65 parts by weight or less, still more preferably 60 parts by weight or less, and particularly preferably 55 parts by weight or less.

Examples of the bisphenol A type epoxy resin include bisphenol A glycidyl ether and brominated bisphenol A diglycidyl ether.
The epoxy equivalent of the bisphenol A type epoxy resin is preferably 200 or more, more preferably 400 or more. Moreover, Preferably it is 1000 or less, More preferably, it is 800 or less.

  The blending amount of the bisphenol A type epoxy resin is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and further preferably 20 parts by weight or more with respect to 100 parts by weight of the solid content of the polyester urethane resin. Yes, particularly preferably 25 parts by weight or more. Moreover, it is preferably 70 parts by weight or less, more preferably 65 parts by weight or less, still more preferably 60 parts by weight or less, and particularly preferably 55 parts by weight or less.

  The compounding ratio of the novolac type epoxy resin and the bisphenol A type epoxy resin is not particularly limited, but preferably the novolak type epoxy resin is 20% by weight or more in the total amount by weight of the novolac type epoxy resin and the bisphenol A type epoxy resin. It mix | blends so that it may become. More preferably, it is 30 weight% or more, More preferably, it is 40 weight% or more. Further, it is preferably 80% by weight or less, more preferably 70% by weight or less, and still more preferably 60% by weight or less.

  If necessary, an epoxy resin other than the novolac type epoxy resin and the bisphenol A type epoxy resin may be used as the adhesive. Specifically, the following epoxy resins are exemplified. Glycidyl ethers such as bisphenol S diglycidyl ether, glycidyl ester types such as hexahydrophthalic acid glycidyl ester, dimer acid glycidyl ester, triglycidyl isocyanurate, tetraglycidyl diaminodiphenylmethane, etc., 3,4-epoxycyclohexylmethylcarboxyl Alicyclic or alicyclic epoxies such as rate, epoxidized polybutadiene, and epoxidized soybean oil.

(Curing agent)
Any conventionally known curing agent for epoxy resins can be used as the curing agent that catalyzes the curing reaction of the epoxy resin.
Diaminodiphenylmethane, diaminodiphenyl sulfide, diaminobenzophenone, diaminodiphenylsulfone, amine compounds such as diethyltriamine, triethylamine, benzyldimethylamine, basic compounds such as triphenylphosphine, 2-alkyl-4-methylimidazole, 2-phenyl- Examples include imidazole derivatives such as 4-alkylimidazole, acid anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride and trimellitic anhydride, amine complexes of boron trifluoride such as boron trifluoride triethylamine complex, and dicyandiamide. You may use these individually or in mixture of 2 or more types. An acid anhydride is preferred, and tetrahydrophthalic anhydride is more preferred.

When an acid anhydride is used, the blending amount thereof is preferably 1 part by weight or more, more preferably 3 parts by weight or more, and still more preferably, based on 100% by weight of the solid content of the polyester polyurethane resin. 5 parts by weight or more. Moreover, Preferably it is 20 weight part or less, More preferably, it is 15 weight part or less, More preferably, it is 10 weight part or less.
In the case of using an acid anhydride, the acid anhydride reacts with the epoxy to form a part of the carboxyl group, so that the acid value of the resin can be adjusted by using the acid anhydride. That is, the acid anhydride can serve not only as a curing agent but also as a function of adjusting the acid value.

  When an imidazole derivative is used as the curing agent, the blending amount is preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more with respect to 100 parts by weight of the solid content of the polyester polyurethane resin. is there. Moreover, Preferably it is 5 weight part or less, More preferably, it is 3 weight part or less, More preferably, it is 1 weight part or less. If the amount used is too small, the epoxy resin may not be sufficiently cured. If it is too high, the curing agent remaining in the final product may adversely affect the performance of the product.

(Glass-transition temperature)
The glass transition temperature (Tg) of the polyester polyurethane resin used for the adhesive is not particularly limited, but is preferably 0 ° C. or higher, more preferably 5 ° C. or higher, still more preferably 8 ° C. or higher, particularly preferably. It is 10 ° C or higher, and particularly preferably 10 ° C or higher. Moreover, it is preferably 50 ° C. or lower, more preferably 40 ° C. or lower, further preferably 30 ° C. or lower, and particularly preferably 25 ° C. or lower. When the glass transition temperature is too low, it is difficult to obtain sufficient heat resistance. When the glass transition temperature is too high, it is difficult to obtain sufficient adhesion.

(Inorganic filler)
An inorganic filler may be added to the adhesive as necessary. Inorganic fillers that can be used include metal oxides such as aluminum hydroxide, magnesium hydroxide, calcium aluminate hydrate, silica, alumina, zinc oxide, antimony trioxide, antimony pentoxide, magnesium oxide, and titanium oxide. Metal oxides such as calcium carbonate, inorganic salts such as calcium carbonate, and carbon black. These inorganic fillers may be used alone or in combination of two or more. For example, if aluminum hydroxide is used, flame retardancy can be improved.

  The inorganic filler may be surface-treated as necessary. Examples of the surface treatment material include silane coupling agents such as 3-aminopropyltriethoxysilane and 3-glycidoxypropyltrimethoxysilane, and silane compounds such as hexamethyldisilazane and chlorosilane.

  The amount of the inorganic filler added is preferably 1 part by weight or more, more preferably 10 parts by weight or more, further preferably 30 parts by weight or more, and particularly preferably 50 parts by weight or more with respect to 100% by weight of the solid content of the resin component. . Moreover, 500 weight part or less is preferable and 150 weight part or less is especially preferable. If the amount is too small, it is difficult to obtain the effect of adding the filler. If the amount is too large, the viscosity of the adhesive may increase and workability may decrease.

  The particle size of the inorganic filler is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. Moreover, it is preferably 0.01 μm or more, more preferably 0.1 μm or more, and further preferably 0.5 μm or more. If the particle size is too large, the wiring pattern may be adversely affected, and those having a very small particle size may be very difficult to obtain.

(Other)
Any conventionally known additive used for the adhesive for flexible printed circuit boards can be added to the adhesive as necessary. For example, an antioxidant or an ion scavenger can be added.
The thickness of the adhesive layer between the cover film and the conductor layer is not particularly limited as long as it does not hinder the performance of the flexible printed wiring board. Preferably it is 1 micrometer or more, More preferably, it is 5 micrometers or more, More preferably, it is 10 micrometers or more. Moreover, it is preferably 100 μm or less, more preferably 50 μm or less. If the thickness is too thin, sufficient adhesiveness may not be obtained. On the other hand, if the thickness is too thick, processability (drying properties, coating properties, laminating properties), etc. may be reduced. is there.
Moreover, about the part from which the conductor layer is removed by the etching etc., the adhesive has a thickness obtained by adding the thickness of the adhesive layer between the cover film and the base film (or base film side adhesive). .

[Metal foil]
A flexible metal-clad laminate can be obtained by laminating with a metal foil using the polyamide-imide resin or resin composition of the present invention. As the metal foil used in the present invention, copper foil, aluminum foil, steel foil, nickel foil and the like can be used, and composite metal foil obtained by compounding these and metal foil treated with other metals such as zinc and chromium compounds. Can also be used. Although there is no limitation in particular about the thickness of metal foil, For example, metal foil of 3-50 micrometers can be used suitably.
The metal foil is usually in the form of a ribbon, and its length is not particularly limited. Also, the width of the ribbon-like metal foil is not particularly limited, but is generally about 25 to 300 cm, particularly about 50 to 150 cm.

[Method for producing double-layer CCL]
In the present invention, the polyamide-imide resin film layer is formed by applying the polyamide-imide resin solution directly or via an adhesive layer to the metal foil, drying the coating film, and optionally heat-treating it.

(Coating)
In the present invention, the polyamide-imide resin solution is applied directly to the metal foil or via an adhesive layer and dried. The application method is not particularly limited, and a conventionally well-known method can be applied. For example, after adjusting the viscosity of the polyamide-imide resin solution, which is the coating solution, with a roll coater, knife coater, doctor, blade coater, gravure coater, die coater, reverse coater, etc., directly on the metal foil or via an adhesive layer Can be applied. The adhesive composition when applied through the adhesive layer is not particularly limited, and acrylonitrile butadiene rubber (NBR) adhesive, polyamide adhesive, polyester adhesive, polyester urethane adhesive, epoxy resin , Acrylic resin, polyimide resin, polyamideimide resin, polyesterimide resin, and other adhesives can be used, but from the viewpoint of heat resistance, adhesiveness, bending resistance, etc., polyimide resin, polyamideimide resin, or A resin composition in which an epoxy resin is blended with these resins is preferable, and the thickness of the adhesive layer is preferably about 5 to 30 μm. Further, from the viewpoint of insulation performance, polyester or polyester urethane resin, or a resin composition in which an epoxy resin is blended with these resins is preferable, and the thickness of the adhesive layer is preferably about 5 to 30 μm. The thickness of the adhesive is not particularly limited as long as it does not hinder the performance of the flexible printed circuit board, but if the thickness is too thin, sufficient adhesiveness may not be obtained. When the thickness is too thick, processability (drying property, coating property) and the like may be deteriorated. As a means for forming a laminated structure through the adhesive layer, a heat-resistant film molded using the heat-resistant resin of the present invention described later and a metal foil are bonded together by the above-mentioned adhesive by a method such as heat lamination. You can also.
In addition, for the purpose of improving various properties of the flexible printed circuit board, the polyamideimide resin solution, which is the coating liquid of the present invention, is applied directly to the metal foil or via the adhesive layer, or after application / drying, It is also possible to further apply an adhesive. The adhesive composition and thickness are the same as described above from the viewpoints of heat resistance, adhesion, bending resistance, curling properties of the flexible printed wiring board, and the conditions for coating and drying are the same as those of the polyamideimide resin solution of the present invention. The same conditions can be applied.

  For example, as shown in Example 12 to be described later, trimellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic acid is further provided on the resin film side of the flexible metal-clad laminate obtained in Example 1 to be described later. By laminating a polyamideimide resin film layer having a different composition obtained from acid dianhydride and o-tolidine diisocyanate, various properties such as HAI resistance, flex resistance and curling property can be improved. Further, as shown in Example 13 described later, a polyimide resin obtained from biphenyltetracarboxylic dianhydride, p-phenylenediamine, etc. on the resin film side of the flexible metal-clad laminate obtained in Example 8 described later. By laminating the layers, various properties such as HAI resistance, flex resistance and curling properties can be improved.

(Dry)
In the present invention, there are no particular limitations on the drying conditions after coating, but generally, after initial drying at a temperature 70 ° C. to 130 ° C. lower than the boiling point (Tb (° C.)) of the solvent used in the polyamideimide resin solution, It is preferable to further dry (secondary drying) at a temperature near the boiling point of the solvent or at a temperature equal to or higher than the boiling point.

  When the initial drying temperature is higher than (Tb-70) ° C., foaming occurs on the coated surface, and unevenness of the residual solvent in the thickness direction of the resin layer increases, so that the bilayer CCL warps (curls). There is a case where the warp of the flexible printed circuit board obtained by processing the circuit becomes large.

  On the other hand, when the drying temperature is lower than (Tb-130) ° C., the drying time becomes longer and the productivity may be lowered. The initial drying temperature varies depending on the type of solvent, but is generally about 60 to 150 ° C, preferably about 80 to 120 ° C. The time required for the initial drying is generally an effective time for the solvent remaining rate in the coating film to be about 5 to 40% under the above temperature conditions, but generally about 1 to 30 minutes, especially 2 ~ 15 minutes.

  The secondary drying conditions are not particularly limited, and may be dried near the boiling point of the solvent or at a temperature equal to or higher than the boiling point, but is generally 120 ° C to 400 ° C, preferably 200 ° C to 300 ° C. When the temperature is 120 ° C. or lower, the drying time becomes longer and the productivity is lowered. When the temperature is 300 ° C. or higher, the deterioration reaction may progress depending on the resin composition, and the resin film may be brittle. The time required for the secondary drying may be an effective time that generally eliminates the solvent remaining rate in the coating film under the above temperature conditions, but is generally about several minutes to several tens of hours.

In the present invention, drying may be performed under an inert gas atmosphere or under reduced pressure. Examples of the inert gas include nitrogen, carbon dioxide, helium, and argon, but it is preferable to use easily available nitrogen. Moreover, when it carries out under reduced pressure, it is preferable to carry out under the pressure of about 10 < ^-5 > -10 < ³ > Pa, preferably about 10 < ^-1 > -200 Pa.

  In the present invention, there are no particular limitations on the drying method for both initial drying and secondary drying, but it can be performed by a conventionally known method such as a roll support method or a floating method. Further, continuous heat treatment in a heating furnace such as a tenter type, winding in a wound state, and heat treatment in a batch type oven may be performed. In the case of a batch type, it is preferable to wind up so that a coating surface and a non-coating surface do not contact.

  The flexible metal-clad laminate of the present invention thus obtained is characterized by being excellent in heat resistance, dimensional stability, and adhesiveness because it has a metal foil directly on at least one surface of the polyamideimide resin film layer. In addition, no imidization process is required and molding is possible only by drying the solvent, or because heat treatment at high temperature is unnecessary, it can be manufactured at low cost and has excellent HAI resistance, flexibility and moisture absorption characteristics. It is characterized by.

  Incidentally, in the flexible metal-clad laminate of the present invention comprising a polyamideimide resin film layer and a metal foil, the thickness of the polyamideimide resin film layer can be selected from a wide range, but in general, the thickness after absolutely dry is 5 About 100 μm, preferably about 10-50 μm. When the thickness is less than 5 μm, the mechanical properties such as film strength and handling properties are inferior. On the other hand, when the thickness exceeds 100 μm, the properties such as flexibility and workability (drying property, coating property) are deteriorated. Tend to. In addition, the flexible metal-clad laminate of the present invention may be subjected to a surface treatment as necessary. For example, surface treatment such as hydrolysis, low-temperature plasma, physical roughening, and easy adhesion coating treatment can be performed.

[Cover film]
As a cover film layer of the flexible printed board of the present invention, any conventionally known insulating film can be used as an insulating film for a flexible printed board. As the resin for the base film, a resin containing halogen may be used, or a resin not containing halogen may be used. From the viewpoint of environmental problems, a resin containing no halogen is preferable, but from the viewpoint of flame retardancy, a resin containing halogen can also be used.

For example, films produced from various polymers such as polyimide, polyester, polyphenylene sulfide, polyethersulfone, polyetheretherketone, aramid, polycarbonate, polyarylate, and polyamideimide can be used.
In particular, from the viewpoint of heat resistance, adhesiveness, dimensional stability, flexibility, insulation, etc. (migration resistance), or HAI resistance, moisture absorption characteristics, and the balance of these various performances, more preferably a polyimide film or A polyamide-imide film, more preferably a polyamide-imide film.

  As the polyimide, any conventionally known resin film can be used. Preferably, tetracarboxylic acid anhydride (pyromellitic acid anhydride or biphenyltetracarboxylic acid anhydride) and diamine (diaminodiphenyl ether or p-phenylene) are used. A resin synthesized by reacting with a diamine) (in N-methyl-2-pyrrolidone, 0.5 g / dl, having a molecular weight corresponding to a logarithmic viscosity at 30 ° C. of 0.3 to 5.0 dl / g) Those having a molecular weight corresponding to 0.8 to 2.5 dl / g, if the logarithmic viscosity is too low, the mechanical properties may be insufficient, If it is too high, the viscosity of the solution becomes high, which may make the molding process difficult.) Or, commercially available Kapton EN (manufactured by Toray DuPont Co., Ltd.), API Le NPI (manufactured by Kaneka Corporation), and the like.

  As the polyamideimide film, any conventionally known resin film can be used, and the polyamideimide resin and the resin composition film of the present invention are particularly preferable.

A cover film can contain arbitrary additives as needed other than a resin component. As such an additive, any additive conventionally used for a flexible printed circuit board (for example, a flame retardant, a lubricant, etc.) can be used.
The thickness of the cover film is not particularly limited as long as it does not hinder the performance of the flexible printed circuit board. The thickness after absolutely dry is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. Moreover, it is preferably 200 μm or less, more preferably 150 μm or less, and still more preferably 100 μm or less. If the thickness is too thin, mechanical properties such as film strength and handling properties may be inferior. On the other hand, if the thickness is too thick, characteristics such as flexibility and workability (drying properties, coating properties, Laminarity) may decrease.
In addition, you may surface-treat to a cover film as needed. For example, surface treatments such as hydrolysis, corona discharge, low temperature plasma, physical roughening, and easy adhesion coating treatment can be applied.

[Flexible printed circuit board]
Using the flexible metal-clad laminate of the present invention, a flexible printed circuit board can be produced by a method such as a subtractive method. When covering the circuit surface for the purpose of protecting the solder resist of the conductor circuit or dirt or scratches, as described above, a heat-resistant film such as polyimide is bonded to the wiring board (conductor circuit) via an adhesive. Or a method of applying a liquid coating agent to a wiring board by a screen printing method. As the liquid coating agent, conventionally known epoxy-based or polyimide-based inks can be used, but polyimide-based inks are preferable. It is also possible to directly bond an epoxy or polyimide adhesive sheet to the wiring board. The flexible printed circuit board thus obtained is excellent in heat resistance, dimensional stability and adhesiveness, and also has excellent resistance to HAI, flexibility, moisture absorption, and insulation, so it can be printed with high voltage and large current. Since it can be used for wiring boards, it has a great industrial advantage.

(Method for manufacturing flexible printed circuit board)
The flexible printed circuit board of the present invention can be manufactured using a conventionally known process except that the material of each layer described above is used.
In a preferred embodiment, a semi-finished product in which an adhesive layer is laminated on a cover film layer (hereinafter referred to as “cover film with adhesive”) is produced. On the other hand, a semi-finished product in which a desired circuit pattern is formed by laminating a metal foil layer on a base film layer (hereinafter referred to as “base film side two-layer semi-finished product”) or an adhesive layer is laminated on the base film layer. Then, a semi-finished product (hereinafter referred to as “base film side three-layer semi-finished product”) in which a desired circuit pattern is formed by laminating a metal foil layer thereon is manufactured. (Hereinafter, “base film side two-layer semi-product” and “base film side three-layer semi-product” are collectively referred to as “base film side semi-product”) By laminating the base film side semi-finished product, a 4-layer or 5-layer flexible printed wiring board can be obtained.

(Manufacturing method of base film side semi-finished product)
A base film side semi-finished product is manufactured by forming a circuit in a metal foil layer using the above-mentioned flexible metal-clad laminate. A conventionally known method can be used to form the circuit. An additive method may be used and a subtractive method may be used. The subtractive method is preferable.
An arbitrary pattern can be formed as the circuit wiring pattern. In particular, the flexible printed circuit board of the present invention exhibits a high level of performance even in a circuit having a fine wiring pattern, and therefore the flexible printed circuit board of the present invention is particularly advantageous in a circuit having a fine wiring pattern.

Specifically, the wiring thickness of the circuit can be 300 μm or less, the wiring thickness can be 150 μm or less, and the wiring thickness can be 100 μm or less. In addition, the thickness of the wiring can be set to 70 μm or less.
The interval between the wirings can be 300 μm or less, can be 150 μm or less, can be 100 μm or less, and can be 70 μm or less. The sum of the wiring thickness and the wiring interval (circuit pitch) can be 600 μm or less, can be 300 μm or less, and can also be 150 μm or less.

  In some cases, in the base film side semi-finished product, an adhesive on the base film side, that is, an adhesive may be used between the base film and the conductor layer. When an adhesive is used between the base film and the conductor layer, the performance of the flexible printed wiring board may be deteriorated due to the adhesive, but the adhesion between the base film and the conductor layer is reduced. If it is not sufficient, it is preferable to use an adhesive.

  When an adhesive is used between the base film and the conductor layer, the adhesive is not particularly limited, and acrylonitrile butadiene rubber (NBR) adhesive, polyamide adhesive, polyester adhesive, polyester urethane adhesive Adhesives such as adhesives, epoxy resin adhesives, acrylic resin adhesives, polyimide resin adhesives, polyamideimide resin adhesives, and polyesterimide resin adhesives can be used. From the viewpoint of bending properties, a polyimide resin system, a polyamideimide resin system, or a resin composition in which an epoxy resin is blended with these resins is preferable, and the thickness of the adhesive layer is preferably about 5 to 30 μm. In addition, a polyester or polyester urethane resin system or a resin composition in which an epoxy resin is blended with these resins is also preferable, and the thickness of the adhesive layer is preferably about 5 to 30 μm. The thickness of the adhesive is not particularly limited as long as it does not hinder the performance of the flexible printed circuit board, but if the thickness is too thin, sufficient adhesiveness may not be obtained. When the thickness is too thick, processability (drying property, coating property, laminating property) and the like may be deteriorated.

Among them, a polyester polyurethane adhesive can be preferably used. More preferably, the adhesive is used as an adhesive on the cover film side. Specifically, a preferred resin for the adhesive is, for example, a polyester polyurethane resin crosslinked with an epoxy resin. Here, Preferably, the total amount of terephthalic acid and isophthalic acid is 70 mol%-100 mol% among 100 mol% of the acid component of a polyester component. Preferably, the isocyanate component of the polyester polyurethane resin contains hexamethylene diisocyanate. Preferably, the polyester polyurethane resin has an acid value of 100 to 1000 equivalents / 10 ⁶ g. Preferably, the number average molecular weight of the polyester polyurethane resin is 8000 to 100,000. Preferably, the epoxy resin is a mixture of a novolac type epoxy resin and a bisphenol A type epoxy resin.

In a preferred embodiment, the cover film side adhesive can be used as the base film side adhesive as the cover film side adhesive.
In one embodiment, the same adhesive as the adhesive on the cover film side can be used as the adhesive on the base film side.

As a means for forming a laminated structure through the adhesive layer, the heat-resistant film molded using the heat-resistant resin of the present invention and the metal foil are bonded together by the above-mentioned adhesive by a method such as heat lamination. You can also.
In addition, depending on the combination of the cover film layer and the adhesive layer, by using an insulating film that can be used for the above-described cover film as a base film, heat resistance, adhesiveness, dimensional stability, flexibility, It is also possible to obtain a flexible substrate that can balance various performances such as insulation properties (migration resistance) and moisture absorption characteristics.

(Manufacturing method of cover film with adhesive)
The cover film with an adhesive is manufactured, for example, by applying an adhesive to the cover film and drying. A preferred adhesive is the above-mentioned adhesive on the cover film side. As a method of laminating the adhesive, a general method can be applied, and there is no particular limitation. It can be applied to an insulating film, dried and laminated. In some cases, it is possible to form an adhesive layer on the releasable film by the above application method, and to laminate the adhesive layer on the insulating film by a transfer method. Drying conditions are set as appropriate according to the adhesive used. Usually, it is about 30 to 150 ° C. If necessary, a crosslinking reaction can be performed in the applied adhesive. In a preferred embodiment, the adhesive layer is semi-cured.

  The obtained cover film with adhesive may be used as it is for pasting with the base material-side semi-finished product, and after sticking and storing the release film, it is pasted with the base film-side semi-finished product. They may be used together.

(Lamination of base film side semi-finished product and cover film with adhesive)
Any method can be used as a method of bonding the base film side semi-finished product and the cover film with adhesive. For example, it can bond together using a press or a roll. Moreover, both can also be bonded together, heating by the method of using a heating press or a heating roll press apparatus.

  For example, if the adhesive layer in the semi-finished product is in an uncured or semi-cured state, it can be cured by proceeding with the crosslinking reaction of the adhesive layer by heating at the time of bonding. It is also possible to easily obtain a final product in which the agent layer is completely cured. When the crosslinking reaction is insufficient, or when it is necessary to precisely control the crosslinking reaction, post-curing can be performed as necessary after pasting by any of the above methods.

[How to use flexible printed circuit board]
The flexible printed circuit board of the present invention can have any laminated structure that can be employed as a flexible printed circuit board. For example, as described above, four layers of a base film layer, a metal foil layer, an adhesive layer, and a cover film layer, or a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer It is possible to make a flexible printed circuit board composed of five layers.

  Further, if necessary, a configuration in which two or three or more of the above-mentioned flexible printed boards are laminated may be employed. For example, it is possible to stack a plurality of the above-mentioned four-layer type flexible printed circuit boards or five-layer type flexible printed circuit boards and bond the flexible printed circuit board and the flexible printed circuit board with an adhesive as necessary. More specifically, for example, the base film layer of the first flexible printed circuit board, the metal foil layer of the first flexible printed circuit board, the adhesive layer of the first flexible printed circuit board, and the cover of the first flexible printed circuit board A film layer; an adhesive layer that bonds the first flexible printed circuit board and the second flexible printed circuit board; a base film layer of the second flexible printed circuit board; a metal foil layer of the second flexible printed circuit board; A total of nine layers of the adhesive layer of the flexible printed circuit board and the cover film layer of the second flexible printed circuit board can be laminated in order.

Further, for example, the four-layer type flexible printed circuit board or the five-layer type flexible printed circuit board may be formed in such a manner that the bottoms of two base film films are bonded to each other by an adhesive layer and back to back. In this case, for example, if the 4-layer type flexible printed circuit board is used,
A cover film layer of a first flexible printed circuit board;
An adhesive layer of the first flexible printed circuit board;
A metal foil layer of the first flexible printed circuit board;
A base film layer of a first flexible printed circuit board;
An adhesive for adhering the base films of the first flexible printed circuit board and the second flexible printed circuit board;
A base film layer of a second flexible printed circuit board;
The metal foil layer of the second flexible printed circuit board A total of 9 layers of the adhesive layer of the second flexible printed circuit board and the cover film layer of the second flexible printed circuit board can be laminated in order.
For example, if the above-mentioned 5-layer type flexible printed circuit board is used,
A cover film layer of a first flexible printed circuit board;
An adhesive layer on the cover film side of the first flexible printed circuit board;
A metal foil layer of the first flexible printed circuit board;
An adhesive layer on the base film side of the first flexible printed circuit board,
A base film layer of a first flexible printed circuit board;
An adhesive for adhering the base films of the first flexible printed circuit board and the second flexible printed circuit board;
A base film layer of a second flexible printed circuit board;
An adhesive layer on the base film side of the second flexible printed circuit board,
A metal foil layer of the second flexible printed circuit board;
An adhesive layer on the cover film side of the second flexible printed circuit board, and a cover film layer of the second flexible printed circuit board,
A total of 11 layers can be stacked in order.

  In addition, a laminated structure of a total of 10 layers in which the adhesive layer on the base film side of the first flexible printed board or the adhesive layer on the second flexible print base film side is omitted, that is, the above four-layer type flexible It is good also as a form which adhere | attached the printed circuit board and the 5-layer type flexible printed wiring board back to back.

[Applications of flexible printed circuit boards]
The flexible printed circuit board of the present invention can be used for various products in which a flexible printed circuit board has been conventionally used. In particular, it can be suitably used for applications that require thin wiring and applications that require a narrow interval between wirings. For example, it is suitable for products whose wiring thickness is 100 μm or less. Further, for example, it is suitable for a product having a wiring interval of 300 μm or less, more suitable for a product having a wiring interval of 150 μm or less, and further suitable for a product having a wiring interval of 100 μm or less. Therefore, it can be suitably used for applications in which the sum (circuit pitch) of the wiring thickness and the wiring interval is narrow. It is suitable for products having a circuit pitch of 600 μm or less, more suitable for products having a circuit pitch of 300 μm or less, further suitable for products having a circuit pitch of 200 μm or less, and particularly suitable for products having a circuit pitch of 150 μm or less.

  Further, since the flexible printed board of the present invention is excellent in insulation (migration), it can be suitably used for applications where a high voltage is applied. For example, it can be used for applications where a voltage of 100 V or higher is applied, and can also be used for applications where a voltage of 200 V or higher is applied.

  Specific examples of the final product in which the flexible printed circuit board of the present invention is used include a plasma display and a mobile phone.

Usually, a flexible printed circuit board used for applications where a high voltage is applied, for example, a flexible printed circuit board used in the periphery of a display such as a plasma display, has a line insulation resistance of 10 ¹⁰ Ω or more even under humidification, It is necessary to maintain insulation reliability of a line breakdown voltage of 1.0 KV or more, and the conventional flexible printed circuit board has insufficient insulation reliability. However, the flexible printed circuit board of the present invention has excellent reliability even in such applications. Expresses sex. The dielectric breakdown voltage between lines and the stability over time of the insulation resistance between lines are the various normal states after heating and humidifying the conductor circuit of the flexible printed circuit board with a voltage of 100 V or more applied. This is a comparison value for the value of.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not particularly limited by the examples.
[Production example of two-layer CCL]
The evaluation method of the characteristic value in each example is as follows. The powdered polyamideimide resin sample used for evaluation was prepared by reprecipitation and purification of the polymer dope obtained in each Example with a large amount of acetone. Moreover, the resin film (base film) was obtained by etching and removing the metal foil of the flexible metal-clad laminate obtained in each Example and Comparative Example with 35% ferric chloride (40 ° C.).

<Logarithmic viscosity>
Using a powdered polymer sample, it was dissolved in N-methyl-2-pyrrolidone so that the polymer concentration would be 0.5 g / dl. Measured and calculated by the following formula.
Logarithmic viscosity (dl / g) = [ln (V ₁ / V ₂ )] / V ₃

In the above formula, V ₁ represents a solution viscosity measured by Ubbelohde viscometer, V ₂ is shown a solvent viscosity measured by Ubbelohde viscometer, V ₁ and V ₂ polymer solution and solvent (N- methyl - 2-pyrrolidone) was determined from the time it took to pass through the capillary of the viscosity tube. V ₃ is the polymer concentration (g / dl).

<Tg>
The glass transition point of the resin film layer obtained by etching away the metal foil of the flexible metal-clad laminate of the present invention by TMA (Thermomechanical Analysis / Rigaku Corporation) tensile load method was measured under the following conditions. The film was measured for a film that was once heated to the inflection point in nitrogen at a heating rate of 10 ° C./min and then cooled to room temperature.
Load: 5g
Sample size: 4 (width) x 20 (length) mm
Temperature increase rate: 10 ° C / min
Atmosphere: Nitrogen

<Coefficient of thermal expansion (CTE)>
The thermal expansion coefficient of the resin film layer obtained by etching away the metal foil of the flexible metal-clad laminate of the present invention by TMA (Thermomechanical Analysis / Rigaku Corporation) tensile load method was measured under the following conditions. The film was measured for a film that was once heated to an inflection point in nitrogen at a heating rate of 10 ° C./min and then cooled to room temperature.
Load: 5g
Sample size: 4 (width) x 20 (length) mm
Temperature increase rate: 10 ° C / min
Atmosphere: Nitrogen
Measurement temperature range: 100 ° C to 200 ° C

<Solder heat resistance>
The metal foil of the flexible metal-clad laminate was etched by the subtractive method, and (35% ferric chloride solution) a circuit pattern with a width of 1 mm was conditioned at 25 ° C and 65% (humidity) for 24 hours. After flux cleaning, it was immersed in a jet solder bath at 320 ° C. for 20 seconds, and the presence or absence of peeling or swelling was observed with a microscope.

<Dimensional change rate>
The measurement was performed in the MD direction and the TD direction under conditions of 150 ° C. × 30 minutes with IPC-FC241 (IPC-TM-650, 2.2.4 (c)).

<Adhesive strength>
According to IPC-FC241 (IPC-TM-650, 2.4.9 (A)), the adhesive strength between the circuit pattern and the heat-resistant resin layer was measured using a sample in which the circuit pattern was created by the subtractive method.

<Hygroscopic rate>
According to IPC-FC241 (IPC-TM-650, 2.6.2 (A)), it measured by the following method. (If the cut surface of the sample is rough, it was finished smoothly with abrasive paper of P240 or higher specified in JIS R 6252)
(1) The dried weighing bottle is dried in an oven at 100 ° C. to 105 ° C. for 1 hour, cooled to room temperature in a desiccator, and accurately weighed to the nearest 0.0001 g (D0). Thereafter, the weighing bottle is returned to the desiccator.
(2) The dried resin film (sample removed by etching) is dried in an oven at 105 ° C. to 110 ° C. for 1 hour. The resin film sample is placed in the weighing bottle of item (1), cooled to room temperature, and accurately weighed to the nearest 0.0001 g (D1).
(3) Take out the resin film sample from the weighing bottle (return the weighing bottle to the desiccator), and adjust the humidity in an atmosphere of 25 ° C. ± 1 ° C. and 90% RH ± 3% RH for 24 hours ± 1 hour.
(4) After humidity control, the resin film sample is put in a weighing bottle and sealed, and after cooling to room temperature in a desiccator, its weight is accurately measured to the unit of 0.0001 g (M1). The weighing bottle is weighed in advance (M0) immediately before the sample is put.
(5) The moisture absorption rate WA (%) is calculated by the following formula.
WA = {(M1−M0) − (D1−D0)} × 100 / {(M1−M0)} (%)

<Flexibility>
An etching film sample having a width of 10 mm and a length of 150 mm was measured according to JIS C 5016 under the conditions of a load of 500 g and a bending diameter of 0.38 mm until the film was broken.

<Strength, elongation and elastic modulus of resin film>
A sample with a width of 10 mm and a length of 100 mm was prepared from a resin film obtained by etching away the metal foil, and a tensile speed of 20 mm / min was measured with a tensile tester (trade name “Tensilon tensile tester”, manufactured by Toyo Baldwin). And the distance between chucks was 40 mm.

<HAI resistance>
Based on the UL746A standard, an arc having a voltage of 240 V, a short-circuit current of 32.5 kg, and a power factor of 50% was generated 40 times per minute, and the number of times until the sample was ignited was measured. In the evaluation, 20 times or more were evaluated as ◎, 15 times or more as ◯, and 10 times or less as ×.

Comparative Example 1
In a reaction vessel, 192 g of trimellitic anhydride (manufactured by Mitsubishi Gas Chemical Co., Inc.), 157 g of 1,5-naphthalene diisocyanate (75 mol%, manufactured by Sumitomo Bayer Urethane Co., Ltd.), 63 g of 4,4′-diphenylmethane diisocyanate (25 mol) %, Manufactured by Sumitomo Bayer Urethane Co., Ltd.), diazabicycloundecene 1 g (manufactured by San Apro Co., Ltd.), and N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) 1836 g (Mitsubishi Chemical Corporation) ) (Polymer concentration: 15%) was added, the temperature was raised to 100 ° C. over 2 hours, and the reaction was allowed to proceed for 5 hours. Subsequently, NMP534g (polymer concentration 12 weight%) was added, and it cooled to room temperature. The obtained polymer dope was yellowish brown transparent and the polymer was dissolved in NMP. The logarithmic viscosity was as shown in Table 1.

Using the polymer solution obtained as described above, a flexible metal-clad laminate was prepared under the following molding process conditions, and various properties with the contents shown in Tables 1 and 2 were evaluated.
(A) Initial drying The resin solution obtained above was removed by using a knife coater on an electrolytic copper foil (trade name “NDP-III”, manufactured by Mitsui Kinzoku Co., Ltd.) having a thickness of 18 μm and a thickness after solvent removal of 25 μm. It was coated so that Subsequently, it dried for 5 minutes at the temperature of 100 degreeC, and obtained the flexible metal-clad laminated body initially dried.
(B) Secondary drying The above initially dried laminate was wound around an aluminum can with an outer diameter of 16 inches so that the coated surface was on the outside, and was heat-treated with a vacuum dryer or an inert oven under the conditions shown below. . The solvent in the coating film of the obtained laminate was completely removed.
Drying conditions under reduced pressure; 200 ° C. × 24 hr (the degree of reduced pressure varied between 10 and 100 Pa due to volatilization of the solvent)
Heating under nitrogen (flow rate; 20 L / min); 260 ° C. × 3 hr

Comparative Examples 2-6
A resin varnish was prepared under the same polymerization conditions as in Comparative Example 1 except that the monomer composition was changed to the contents shown in Table 1. Next, a flexible metal-clad laminate was prepared under the same conditions as in Comparative Example 1, and various characteristics having the contents shown in Tables 1 and 2 were evaluated.

Examples 1-8
A resin varnish was prepared under the same polymerization conditions as in Comparative Example 1 except that the monomer composition was changed to the contents shown in Table 1. Next, a flexible metal-clad laminate was prepared under the same conditions as in Comparative Example 1, and various characteristics having the contents shown in Tables 1 and 2 were evaluated.

Examples 9-11
The silicone compound (additive) shown in Table 1 is added to the polymerization dope obtained by the production method described in Example 1 in an amount shown in Table 1 with respect to 100 parts by weight of the solid content of the polyamideimide resin. Reacted for hours. Using the obtained resin varnish, a flexible metal-clad laminate was prepared by the method described in Comparative Example 1, and then the metal foil was etched away with 35% ferric chloride (40 ° C.) to obtain a film. It was. Next, various characteristics shown in Tables 1 and 2 were evaluated.

Example 12 (Example in which a polyamide-imide resin is further laminated)
In a reaction vessel, 144 g of trimellitic anhydride (manufactured by Mitsubishi Gas Chemical Co., Inc.), 64 g of benzophenone tetracarboxylic dianhydride (manufactured by Daicel Chemical Industries), 15 g of biphenyl tetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation) ), O-tolidine diisocyanate 264 g (manufactured by Nippon Soda Co., Ltd.), triethylenediamine 3 g (manufactured by Nacalai Tesque), and N-methyl-2-pyrrolidone 2300 g (manufactured by Mitsubishi Chemical Corporation) (polymer concentration 15) %), The temperature was raised to 100 ° C. over 2 hours, and the reaction was allowed to proceed for 5 hours. Next, 726 g of NMP (polymer concentration: 12% by weight) was added, and the mixture was cooled to room temperature. The obtained polymer dope was yellowish brown transparent and the polymer was dissolved in NMP. The polymer solution obtained as described above was applied to the resin surface of the flexible metal-clad laminate obtained in Example 1 so that the thickness after drying was 10 μm, and under the molding processing conditions described in Comparative Example 1. A flexible metal-clad laminate was created. There was no curl of the flexible metal-clad laminate thus obtained, and there was no curl of the film obtained by etching the metal foil. Further, the film obtained by etching had a moisture absorption rate of 1.4% and a HAI resistance of 20 times. Further, the flexible printed wiring board obtained from the flexible printed metal-clad laminate had a bending resistance of 13270 times.

Example 13 (Example in which polyimide resin is further laminated)
a) 54 g of p-phenylenediamine (manufactured by Nacalai Tesque) and 1810 g of N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical) were added to the reaction vessel, and after cooling to 5 ° C., the mixture was stirred and dissolved. Subsequently, 147 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation) was gradually added and reacted at 5 ° C. for 2 hours (polymer concentration 10%). Next, 1 g of 2-hydroxypyridine (2 mol% based on the monomer; manufactured by Nacalai Tesque) was added and reacted for 1 hour. The obtained polymer dope was light yellowish brown and transparent, and the polymer was dissolved in NMP. The logarithmic viscosity was 2.0 dl / g.
The polymer solution obtained as described above was applied to the resin surface of the flexible metal-clad laminate obtained in Example 8 so that the thickness after drying was 10 μm, and under the molding process conditions described in Comparative Example 1. A flexible metal-clad laminate was created. There was no curl of the flexible metal-clad laminate thus obtained, and there was no curl of the film obtained by etching the metal foil. Further, the film obtained by etching had a moisture absorption rate of 1.5% and a HAI resistance of 23 times. Moreover, the bending resistance of the flexible printed wiring board obtained from the flexible printed metal-clad laminate was 12300 times.

b) 43 g of p-phenylenediamine (50 mol%; manufactured by Nacalai Tesque), 3200 g of N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical), 80 g of 4,4′-diaminodiphenyl ether (50) Mol%; manufactured by Nacalai Tesque Co., Ltd.) was added, and the mixture was cooled to 5 ° C. and stirred to dissolve. Next, 236 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation) was gradually added and reacted at 5 ° C. for 2 hours (polymer concentration 10%). Next, 1 g of 2-hydroxypyridine (2 mol% based on the monomer; manufactured by Nacalai Tesque) was added and reacted for 1 hour. The obtained polymer dope was light yellowish brown and transparent, and the polymer was dissolved in NMP. The logarithmic viscosity was 1.9 dl / g.
The polymer solution obtained as described above was applied to the resin surface of the flexible metal-clad laminate obtained in Example 8 so that the thickness after drying was 10 μm, and under the molding process conditions described in Comparative Example 1. A flexible metal-clad laminate was created. There was no curl of the flexible metal-clad laminate thus obtained, and there was no curl of the film obtained by etching the metal foil. Further, the film obtained by etching had a moisture absorption rate of 1.7% and a HAI resistance of 24 times. Moreover, the bending resistance of the flexible printed wiring board obtained from the flexible printed metal-clad laminate was 14700 times.

Example 14
In a reaction vessel, 190 g of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (40 mol%; manufactured by Daicel Chemical Industries), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride 88 g (20 mol%; manufactured by Mitsubishi Chemical Corporation), pyromellitic anhydride 33 g (10 mol%; manufactured by Mitsubishi Chemical Corporation), terephthalic acid 50 g (20 mol%; manufactured by Mitsubishi Gas Chemical Co., Ltd.) , 25 g of isophthalic acid (10 mol%; manufactured by Mitsubishi Gas Chemical Co., Inc.), 315 g of 1,5-naphthalenediocyanate (100 mol%, manufactured by Sumitomo Bayer Urethane Co., Ltd.), 3 g of diazabicycloundecene (San Apro Corporation) Product) and 3000 g of N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation) (polymer concentration 16%) were added, the temperature was raised to 100 ° C. over 2 hours, and the reaction was allowed to proceed for 5 hours. Next, 534 g (polymer concentration 12% by weight) of diglyme was gradually added and cooled to room temperature. The obtained polymer dope was yellowish brown transparent and the polymer was dissolved in NMP. The logarithmic viscosity was as shown in Table 3.

Using the polymer solution obtained as described above, a flexible metal-clad laminate was prepared under the following molding process conditions, and various properties with the contents shown in Tables 3 and 4 were evaluated.
(A) Initial drying Using the knife coater on the electrolytic copper foil (trade name “USLP-SE”, manufactured by Nihon Denki Co., Ltd.) having a thickness of 18 μm, the resin solution obtained above has a thickness after solvent removal of 20 μm. It was coated so that Subsequently, it dried for 5 minutes at the temperature of 100 degreeC, and obtained the flexible metal-clad laminated body initially dried.
(B) Secondary drying The above initially dried laminate was wound around an aluminum can with an outer diameter of 16 inches so that the coated surface was on the outside, and was heat-treated with a vacuum dryer or an inert oven under the conditions shown below. . The solvent in the coating film of the obtained laminate was completely removed.
Drying conditions under reduced pressure; 200 ° C. × 24 hr (the degree of reduced pressure varied between 10 and 100 Pa due to volatilization of the solvent)
Heating under nitrogen (flow rate; 20 L / min); 260 ° C. × 10 hr

Examples 15-17
A resin varnish was prepared under the same polymerization conditions as in Example 14 except that the monomer composition was changed to the contents shown in Table 3. Next, a flexible metal-clad laminate was prepared under the same conditions as in Example 14, and various characteristics shown in Tables 3 and 4 were evaluated.

Examples 18-21
Into the polymerization dope obtained by the production method described in Example 8, the silicon (silica) compound (additive) shown in Table 3 was added in an amount shown in Table 3 with respect to 100 parts by weight of the solid content of the polyamideimide resin, and dispersed. did. (Dispersion was performed in the dilute solution of Example 8 and added to the dope of Example 8 in a predetermined amount) Using the obtained resin varnish, a flexible metal-clad laminate was prepared by the method described in Example 14, Various characteristics shown in Tables 3 and 4 were evaluated.

Examples 22-27
The polymer dope obtained by the production method described in Example 8 was blended with the resin varnish shown in Table 3 in an amount shown in Table 3 with respect to 100 parts by weight of the solid content of the polyamideimide resin. Using the obtained resin varnish, a flexible metal-clad laminate was prepared by the method described in Example 14, and various characteristics shown in Tables 3 and 4 were evaluated.

Synthesis Example 1 Production Example of Polyimide Resin for Blending a) 43 g (50 mol%) of p-phenylenediamine (manufactured by Nacalai Tesque), 4,4′-diaminodiphenyl ether (manufactured by Nacalai Tesque) in a reaction vessel 80 g (50 mol%) and 3230 g (polymer concentration 10%) of N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation) were added, and the mixture was cooled to 5 ° C., stirred and dissolved. Subsequently, 235 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation) was gradually added and reacted at 5 ° C. for 5 hours. The obtained polymer dope was light yellowish brown and transparent, and the polymer was dissolved in NMP. The logarithmic viscosity was 2.0 dl / g.
b) 78 g (90 mol%) of p-phenylenediamine (manufactured by Nacalai Tesque), 16 g (10 mol%) of 4,4'-diaminodiphenyl ether (manufactured by Nacalai Tesque), N-methyl- 2-Pyrrolidone (Mitsubishi Chemical Co., Ltd.) 2960 g (polymer concentration 10%) was added, cooled to 5 ° C., stirred and dissolved. Subsequently, 235 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation) was gradually added and reacted at 5 ° C. for 5 hours. The obtained polymer dope was light yellowish brown and transparent, and the polymer was dissolved in NMP. The logarithmic viscosity was 2.4 dl / g.

[Example of heat-resistant film production]
Example 28
The resin varnish prepared in Example 2 was applied to a PET film having a thickness of 100 μm with a knife coater so that the thickness after drying was 25 μm. Subsequently, after 5 minutes finger-drying at 100 ° C., the film was peeled from the PET film to obtain a self-supporting film.
The obtained film was fixed to the stainless steel frame at the top and bottom and left and right ends, and heat-treated with a vacuum dryer or an inert oven under the conditions shown below. The obtained film was transparent and the solvent in the coating film was completely removed. The film properties were as shown in Table 5.
Drying conditions under reduced pressure; 200 ° C x 24 hours
(The degree of vacuum varied between 10 and 100 Pa due to solvent volatilization)
Heating under nitrogen (flow rate; 20 L / min); 260 ° C. × 10 hr

Examples 29-35
A film was prepared in the same manner as in Example 28 except that the resin varnish used was changed to the contents shown in Table 5, and the characteristics shown in Table 5 were evaluated.

Comparative Examples 7-9
A film was prepared in the same manner as in Example 28 except that the resin varnish used was changed to the contents shown in Table 5, and the characteristics shown in Table 5 were evaluated.

[Production example of adhesive]
Each measurement evaluation item of polyester resin and polyester urethane resin followed the following method. In addition, the following measurement evaluation item of the polyester polyurethane resin removed the solvent by drying the solution obtained by the following synthesis example at 120 degreeC for 1 hour, and performed each measurement for the obtained solid according to the following method.
(1) Resin composition: using a nuclear magnetic resonance analyzer (NMR) Gemini 200 manufactured by Varian in deuterated chloroform solvent. ¹ H-NMR analysis was performed and determined from the integration ratio.
(2) Number average molecular weight: Calculated from the results of GPC measurement at a column temperature of 35 ° C. and a flow rate of 1 ml / min using Waters Gel Permeation Chromatography (GPC) 160C with tetrahydrofuran as an eluent. The calculated value of polystyrene conversion was obtained. However, Showa Denko Co., Ltd. shodex KF-802, 804, 806 was used for the column.
(3) Glass transition point: 5 mg of sample was put in an aluminum sample pan and sealed, and heated to 200 ° C. using a differential scanning calorimeter (DSC) DSC-220 manufactured by Seiko Instruments Inc. Measured at a rate of 20 ° C./min. For the glass transition temperature, the temperature at the intersection with the tangent indicating the maximum slope at the extended line transition of the base line was obtained.
(4) Measurement of acid value: 0.2 g of sample was dissolved in 20 cm ³ of chloroform and titrated with 0.1 N potassium hydroxide ethanol solution to obtain the equivalent (eq / 10 ⁶ g) per 10 ⁶ g of resin. It was. Phenolphthalein was used as the indicator.

Synthesis example 2; Production example of polyester urethane adhesive (synthesis of polyester)
In a reaction vessel equipped with a thermometer, stirrer, reflux condenser and distillation tube, 66.4 parts of terephthalic acid, 64.7 parts of isophthalic acid, 29.2 parts of adipic acid, 1.9 parts of trimellitic anhydride, 2- First, 126 parts of methyl-1,3-propanediol, 72 parts of 1,4-butanediol and 0.07 part of tetrabutyl titanate were added, and the temperature was gradually raised to 230 ° C. over 4 hours. The esterification reaction was carried out while removing. Subsequently, this was subjected to reduced pressure initial polymerization until 10 mmHg over 20 minutes, and the temperature was raised to 240 ° C., and further subjected to late polymerization at 1 mmHg or less for 1 hour, then returned to normal pressure, under a nitrogen stream, The mixture was cooled to 220 ° C., 1.9 parts of trimellitic anhydride was added, and the mixture was stirred at 220 ° C. for 1 hour to allow the trimellitic anhydride to react with the polyester to obtain the target polyester. The characteristic values of the polyester thus obtained were as follows.
Resin composition Acid component; Terephthalic acid 40 mol%
Isophthalic acid 39 mol%
Adipic acid 18 mol%
Trimellitic acid 2 mol%
Glycol component;
2-Methyl-1,3-propanediol 60 mol%
1,4-butanediol 40 mol%
Number average molecular weight; 12000
Glass transition point: 12 ° C
Acid value: 110 equivalent / t

(Synthesis example of polyester polyurethane)
A reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a distillation tube was charged with 100 parts of the polyester obtained by the polyester synthesis example and 100 parts of toluene, and the resin was dissolved at 100 ° C. Thereafter, the temperature was raised to 130 ° C., 60.8 parts of toluene was distilled, and the reaction system was dehydrated by azeotropic distillation of toluene and water. Thereafter, the system was cooled to 60 ° C., 39.1 parts of methyl ethyl ketone and 9 parts of dimethylolbutanoic acid were charged, and the mixture was stirred at 60 ° C. for 30 minutes. Subsequently, 0.2 part of dibutyltin dilaurate was added, the temperature was raised to 80 ° C. for reaction, and after completion of the reaction, 98 parts of methyl ethyl ketone was added to adjust the solid content concentration to 40% to obtain the desired polyester polyurethane. The characteristic values of the polyester polyurethane thus obtained were as follows.
Number average molecular weight; 15000
Glass transition point: 10 ° C
Acid value: 630 equivalent / t

(Manufacturing example of adhesive)
In a reaction vessel equipped with a thermometer, a stirrer and a reflux condenser, 125 parts of the polyester polyurethane solution obtained in the synthesis example of polyester polyurethane, 133.5 parts of methyl ethyl ketone, and BREN-S (Nippon Kayaku Co., Ltd.) as an epoxy resin 25 parts of brominated phenol novolac type epoxy resin), 15 parts of Epicoat 5051 (brominated bisphenol A type epoxy resin manufactured by Japan Epoxy Resin Co., Ltd.), bromine manufactured by Epicoat 872 (Japan Epoxy Resin Co., Ltd.) 10 parts of bisphenol A type epoxy resin), 2 parts of Rikagit TH (Shin Nippon Rika Co., Ltd. ethylene glycol bis (anhydrotrimellitate)) as a curing agent, Kayamar PM2 (Nippon Kayaku ( Acrylic phosphorus-containing monomer (made by Co., Ltd.) After dissolution, 0.6 parts of 2HPZ-CN (imidazole compound manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a curing catalyst, C11Z-A (2, 4-diamino-6- (2 ′ manufactured by Shikoku Kasei Kogyo Co., Ltd.) -Undecylimidazolyl) -ethyl-S-triazine) 0.4 parts and 30 parts of aluminum hydroxide as a flame retardant were added and sufficiently stirred to obtain a desired adhesive solution.

Comparative Synthesis Example 1: Comparative production example of polyester urethane adhesive (comparative production example of polyester urethane)
A reaction vessel equipped with a thermometer, a stirrer, and a distillation tube was charged with 100 parts of polypropylene glycol having a number average molecular weight of 1000 and 100 parts of toluene, and the resin was dissolved at 100 ° C. Thereafter, the temperature was raised to 130 ° C., 55 parts of toluene was distilled, and the reaction system was dehydrated by azeotropic distillation of toluene and water. Thereafter, the system was cooled to 60 ° C., 45 parts of methyl ethyl ketone and 3 parts of neopentylprecol were added and stirred at 60 ° C. for 30 minutes. Thereafter, 32 parts of 4,4′-diphenylmethane diisocyanate was charged and stirred at 60 ° C. for 30 minutes. Subsequently, 0.2 part of dibutyltin dilaurate was added, the temperature was raised to 80 ° C. for reaction, and after completion of the reaction, 112.5 parts of methyl ethyl ketone was added to adjust the solid content concentration to 40% to obtain a polyether polyurethane. The characteristic values of the polyester polyurethane thus obtained were as follows.
Number average molecular weight; 12000
Glass transition point: -30 ° C
Acid value: 3 equivalent / t

(Comparative example of adhesive)
In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 250 parts of the polyether polyurethane solution obtained in the comparative synthesis example of polyether polyurethane, 73.5 parts of methyl ethyl ketone, and BREN-S (Nipponization) as an epoxy resin 20 parts of brominated phenol novolac type epoxy resin manufactured by Yakuhin Co., Ltd., 15 parts of YDB400 (brominated bisphenol A type epoxy resin manufactured by Toto Kasei Co., Ltd.), 3,3 ′, 4,4 as curing agent Charge 5 parts of '-benzophenonetetracarboxylic dianhydride and 3 parts of Rikagit TMTA-C (glycerol tris anhydrotrimellitate manufactured by Shin Nippon Rika Co., Ltd.), dissolve at 50 ° C, and then use 2PHZ as a curing catalyst. -CN (Shikoku Chemicals Co., Ltd. imidazole compound) 0.6 parts, C11Z-A ((Shikoku Chemicals Co., Ltd.) 0.4 part of 2,4-diamino-6- (2′-undecylimidazolyl) -ethyl-S-triazine) manufactured by the company, 5 parts of antimony trioxide as a flame retardant aid were added and sufficiently stirred to obtain an adhesive solution. Got.

[Production example of film with adhesive]
Example 36
The adhesive prepared in Synthesis Example 2 was applied to the polyamideimide film produced in Example 35 with a comma coater so that the thickness after drying was 25 μm, and dried at 80 ° C. for 3 minutes and 150 ° C. for 3 minutes. Thus, a film with an adhesive was obtained. The laminate did not warp and was good in appearance. Subsequently, the releasable PET film was bonded and stored in an atmosphere of 25 ° C., 65% RH, and 40 ° C. for 24 hours.

Example 37
The adhesive prepared in Synthesis Example 2 was applied to the polyamideimide film produced in Example 34 with a comma coater so that the thickness after drying was 25 μm, and dried at 80 ° C. for 3 minutes and 150 ° C. for 3 minutes. Thus, a film with an adhesive was obtained. The laminate did not warp and was good in appearance. Subsequently, the releasable PET film was bonded and stored in an atmosphere of 25 ° C., 65% RH, and 40 ° C. for 24 hours.

Comparative Example 10
The adhesive prepared in Synthesis Example 2 was applied to a polyimide film having a thickness of 25 μm (Apical NPI manufactured by Kaneka Chemical Co., Ltd.) with a comma coater so that the thickness after drying would be 25 μm, and 80 ° C. For 3 minutes and at 150 ° C. for 3 minutes to obtain a film with an adhesive. The laminate did not warp and was good in appearance. Subsequently, the releasable PET film was bonded and stored in an atmosphere of 25 ° C., 65% RH, and 40 ° C. for 24 hours.

Comparative Example 11
The adhesive prepared in Comparative Synthesis Example 1 was applied to a polyimide film having a thickness of 25 μm (Apical NPI manufactured by Kaneka Chemical Co., Ltd.) with a comma coater so that the thickness after drying was 25 μm. The film was dried at 150 ° C. for 3 minutes and at 150 ° C. for 3 minutes to obtain a film with an adhesive. Subsequently, the releasable PET film was bonded and stored in an atmosphere of 25 ° C., 65% RH, and 40 ° C. for 24 hours.

[Production example of 3-layer CCL]
Comparative Example 12
The matte surface (treated surface) of the electrolytic copper foil (Nippon Electrolytic Co., Ltd. USLP-SE) and the adhesive surface of the film with adhesive produced in Comparative Example 10 were superposed on each other, and the temperature was 160 ° C. and the pressure was 20 kgf / cm ^2. Roll lamination was performed under the condition of a passing speed of 3 m / min. Next, after-curing was performed at 100 ° C. for 16 hours to obtain a CCL with good appearance and no curling.

Example 38
A CCL having good appearance without curling was produced in the same manner as in Comparative Example 12 except that the film with adhesive produced in Example 36 was used.

[Example of flexible printed circuit board production]
Example 39
A photosensitive resist is laminated on the copper foil surface of the two-layer flexible metal-clad copper clad laminate produced in Example 8, and is exposed, baked and developed with a mask film (IPC-FC241, JIS Z 3197, or The evaluation pattern described in JIS C 5016) was transferred. Next, using a 35% cupric chloride solution at 40 ° C., the copper foil was removed by etching, and the resist used for circuit formation was removed with an alkali to perform circuit processing.
Next, the adhesive film produced in Example 37, in which the necessary portions for electrical connection were previously punched and punched with a mold, were overlaid so that the adhesive layer was in contact with the circuit surface, and press lamination (160 ° C. × 4 minutes, pressure 20 kgf / cm ² (196.138 N / cm ² )) and after-curing (100 ° C. × 16 hours) to obtain a flexible printed wiring board.
Various characteristics shown in Table 7 were evaluated for the flexible printed circuit board obtained as described above.

In addition, evaluation of the flexible printed circuit board was performed as follows.
(Evaluation of insulation (migration resistance))
Using a comb-type electrode defined in JIS Z 3197 defined in Table 6 (a flexible printed circuit board in which only the pitch of the pattern is changed to the content in Table 7 and covered), under an atmosphere of 85 ° C. and 85% RH, The line insulation resistance value (DC500V ± 5V applied, after holding for 1 minute) of the time-lapsed sample prepared by continuously energizing for 1500 hours (DC100V) was measured by the method of JIS C 5016.

(Adhesion evaluation)
The flexible printed circuit board is cut into a strip shape having a width of 3 mm, and in accordance with IPC-FC241 (IPC-TM-650, 2.4.9 (A)), the adhesive strength between the copper foil surface and the base film surface and the cover film. Was measured and the lowest value was defined as the adhesive strength.

(Evaluation of heat resistance)
In accordance with JIS C5016 standard, the temperature of the jet solder bath was raised from 240 ° C. to 340 ° C. in increments of 10 ° C., and the upper limit temperature at which appearance changes such as peeling and blistering did not occur was measured. The sample was conditioned at 25 ° C. and 65% (RH) for 24 hours and flux washed.

(Evaluation of bending resistance)
Measurements were made at a bending diameter of 0.38 mm and 1.0 mm according to JIS-C-5016.

Examples 40-44, Comparative Examples 13-15
A flexible printed wiring board was obtained in the same manner as in Example 39 except that the flexible metal-clad copper clad laminate and the cover film with adhesive were changed to those shown in Table 7. Next, various characteristics shown in Table 7 were evaluated.

  As mentioned above, although this invention has been illustrated using preferable embodiment of this invention, this invention should not be limited and limited to this embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments of the present invention. Patents, patent applications and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Is understood.

  As described above, the flexible metal-clad laminate of the present invention is composed of a heat-resistant polyamide-imide resin that simultaneously satisfies the solvent solubility / HAI resistance / low elastic modulus / low hygroscopic properties. It has excellent properties, dimensional stability, adhesiveness and insulation, and also has excellent HAI resistance, flexibility and moisture absorption properties. Moreover, since the internal stress of the flexible metal-clad laminate can be reduced by molding according to the molding processing conditions of the present invention, it does not curl and exhibits excellent dimensional stability. Furthermore, since the polyamideimide resin used is soluble in an organic solvent, it can be manufactured at low cost. Therefore, there is a great industrial advantage because a flexible printed circuit board that can be used even for printed wiring boards loaded with high voltage or large current can be manufactured at low cost.

Claims (24)

At least one selected from the group consisting of general formula (1) and general formula (2), general formula (3) and general formula (4) is an essential component, and the copolymerization ratio is {general formula (1)} / {Polyamideimide resin which is General formula (2) + General formula (3) + General formula (4)} = 99 / 1-5 / 95 (molar ratio).

(X represents an oxygen atom, CO, SO ₂ , or direct connection, and n represents 0 or 1)

(Y represents an oxygen atom, CO, or OOC-R-COO, n represents 0 or 1, and R represents a divalent organic group.)

  At least one selected from the group consisting of general formula (2) and general formula (3) and general formula (4) is an essential component, and the copolymerization ratio thereof is {general formula (2)} / {general formula (3 ) + General formula (4)} = 95/5 to 5/95 (molar ratio). In the general formula (2), the bond ratio of the ratio in which the amide bond is in the para position and the ratio in the meta position is para position / meta position = 5/95 to 100/0 mol%. The polyamide-imide resin described. The polyamideimide resin according to claim 1 or 2, wherein the general formula (2) is the general formula (5).

(X represents an oxygen atom, CO, SO ₂ , or direct connection, and n represents 0 or 1)   The polyamide-imide resin according to any one of claims 1 to 4, which is non-halogen-based.   The polyamide-imide resin according to claim 5, which is soluble in an organic solvent.   The polyamideimide resin according to claim 6, which has a HAI resistance of 15 times or more.   A polyamideimide resin obtained by reacting the polyamideimide resin according to claim 1 with a silicone compound.   The polyamide-imide resin composition which mixed the silicone compound with the polyamide-imide resin in any one of Claims 1-7.   The polyamide-imide resin composition which mixed the polyamide-imide resin in any one of Claims 1-7 with the silica.   The polyamideimide resin composition according to claim 10, wherein the silica particle system is 1 nm to 10 μm.   A polyamideimide resin composition obtained by blending the polyamideimide resin according to any one of claims 1 to 7 with a polyimide resin containing a biphenyl skeleton and / or a polyamideimide resin (including precursors thereof). A polyamideimide resin composition obtained by blending the polyamideimide resin according to any one of claims 1 to 7 with a polyamideimide resin containing 3,3'-dimethyl-4,4'-diaminobiphenyl as an essential component as an amine component. Stuff.   The acid component of the polyamide-imide resin containing 3,3′-dimethyl-4,4′-diaminobiphenyl as an essential component is an essential component of trimellitic anhydride, benzophenonetetracarboxylic dianhydride and biphenyltetracarboxylic dianhydride The polyamidoimide resin composition of Claim 13 included as.   A varnish obtained by dissolving the polyamideimide resin according to any one of claims 1 to 8 or the polyamideimide resin composition according to any one of claims 9 to 14 in an organic solvent.   Organic solvent is N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethylsulfoxide, γ-butyrolactone , At least one selected from the group consisting of cyclohexanone and cyclopentanone, or at least one selected from the group consisting of toluene, xylene, diglyme, triglyme, tetrahydrofuran, methyl ethyl ketone and methyl isobutyl ketone. The varnish of claim 15 replaced.   The film obtained from the polyamide-imide resin in any one of Claims 1-8, or the polyamide-imide resin composition in any one of Claims 9-14.   The film by which the adhesive agent was laminated | stacked on the at least one surface of the film of Claim 17. The adhesive contains an epoxy resin and a polyester urethane resin, the epoxy resin contains a novolac type epoxy resin and a bisphenol A type epoxy resin, and the polyester urethane resin has the following (1), (2), (3 The film according to claim 18, which satisfies the conditions of (4) and (4).
(1) Among 100 mol% of the acid component of the polyester component, the total content of terephthalic acid and isophthalic acid is 70 mol% to 100 mol%,
(2) the isocyanate component contains hexamethylene diisocyanate,
(3) Acid value is 100-1000 equivalent / 10 < ⁶ > g,
(4) The number average molecular weight is 8000 to 100,000.   A metal foil is directly laminated on at least one side of the polyamideimide resin according to any one of claims 1 to 8 or the polyamideimide resin composition according to any one of claims 9 to 14, or laminated via an adhesive layer. Flexible metal-clad laminate.   A flexible printed circuit board obtained from the metal-clad laminate according to claim 20.   In the flexible printed board containing a base film layer, a conductor layer, an adhesive layer, and a cover film layer, the cover film layer is the polyamide-imide resin according to any one of claims 1 to 8, or any one of claims 9 to 14. A flexible printed circuit board comprising the polyamideimide resin composition according to claim 1.   In the flexible printed board containing a base film layer, a conductor layer, an adhesive layer, and a cover film layer, the base film layer is the polyamideimide resin according to any one of claims 1 to 8, or the claims 9 to 14 A flexible printed circuit board comprising the polyamideimide resin composition according to any one of the above. The adhesive layer contains a polyester urethane resin crosslinked with an epoxy resin, the epoxy resin contains a novolac type epoxy resin and / or a bisphenol A type epoxy resin, and the polyester urethane resin has the following (1) 24) The flexible printed wiring board according to claim 22 or 23, wherein the conditions of (2), (3), and (4) are satisfied.
(1) Among 100 mol% of the acid component of the polyester component, the total content of terephthalic acid and isophthalic acid is 70 mol% to 100 mol%,
(2) the isocyanate component contains hexamethylene diisocyanate,
(3) Acid value is 100-1000 equivalent / 10 < ⁶ > g,
(4) The number average molecular weight is 8000 to 100,000.