JP2007230019A - Manufacturing method of metal clad laminated sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a metal clad laminated sheet, which is suitably used in a flexible printed wiring board or the like and composed of at least a conductor and a plurality of polyimide layers, having drastically higher productivity as compared with that of a conventional method. <P>SOLUTION: The manufacturing method of the metal clad laminated sheet wherein at least two kinds of the polyimide layers are provided on the conductor includes a process for forming at least two layers by casting at least two kinds of solutions, each of which is a solution selected from a solution containing a precursor of a polyimide resin and a solution containing the polyimide resin and contains a solution containing at least one kind of the precursor of the polyimide resin, on the conductor by coextrusion and is characterized in that a chemical dehydrating agent and a catalyst are added to the solution containing at least one kind of the precursor of the polyimide of the solutions used in coextrusion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metal-clad laminate suitably used for a flexible printed wiring board and the like. More specifically, the present invention relates to a method for producing a metal-clad laminate comprising at least a conductor and a plurality of polyimide layers.

  In recent years, the demand for various printed circuit boards has increased with the reduction in weight, size and density of electronic products. Among these printed boards, the demand for flexible wiring boards is growing. The flexible wiring board is also referred to as a flexible printed wiring board (FPC). The flexible laminate has a structure in which a circuit made of a metal foil is formed on an insulating film.

  The flexible laminate is generally formed of various insulating materials, and a flexible insulating film is used as a substrate, and a metal foil is bonded to the surface of the substrate by heating and pressure bonding via various adhesive materials. Manufactured by. A polyimide film or the like is preferably used as the insulating film, and an epoxy or acrylic thermosetting adhesive is generally used as the adhesive material. A flexible wiring board using such a thermosetting adhesive has a three-layer structure of substrate / adhesive material / metal foil, and is also referred to as a three-layer FPC.

  The thermosetting adhesive used for the three-layer FPC has an advantage that it can be bonded at a relatively low temperature. However, as the requirements for various characteristics such as heat resistance, flexibility, and electrical reliability for FPC become stricter in the future, it is considered that the three-layer FPC using a thermosetting adhesive becomes difficult to cope with.

  On the other hand, FPCs in which a metal layer is directly provided on an insulating film and FPCs using thermoplastic polyimide as an adhesive layer have been proposed. Such an FPC is also called a two-layer FPC because a metal layer is directly formed on an insulating substrate. This two-layer FPC has characteristics superior to those of the three-layer FPC and can sufficiently meet the demands for the various characteristics described above, so that demand is expected to increase in the future.

  The two-layer FPC is manufactured using a metal-clad laminate having a structure in which a metal foil is laminated on a substrate. The metal-clad laminate can be produced by casting a polyamic acid, which is a polyimide precursor, on a conductor, casting it, then imidizing it, and metalizing by directly forming a metal layer on the polyimide film by sputtering or plating. And a laminating method in which a polyimide film and a metal foil are bonded via a thermoplastic polyimide.

  Of these, the casting method is the most productive, and is therefore the most cost effective method for producing metal-clad laminates.

  In the casting method, in order to provide both adhesiveness and dimensional stability, it is generally performed to provide a plurality of polyimide resin layers on a conductor. As a method of producing a plurality of polyimide resin layers on a conductor, one polyimide precursor solution is cast on a conductor and dried, and then the next polyimide precursor solution is cast thereon (for example, a sequential casting method (for example, Patent Document 1) and a coextrusion method (for example, Patent Document 2) in which a plurality of polyimide precursor solutions are simultaneously cast on a conductor using a coextrusion die are known.

  Among these, the co-extrusion method is more advantageous than the sequential casting method because it is superior in productivity and because there are fewer steps of defects such as contamination due to fewer steps.

However, the conventional coextrusion method has been studied on the premise of a so-called thermal curing method in which imidization is substantially performed only by heating. The thermal curing method has a problem in that productivity is low because the process of volatilization / removal of the solvent and imidization in the film forming process takes a very long time. The low productivity has the problem of increasing the total cost.
Japanese Patent Laid-Open No. 10-323935 Japanese Patent Publication No. 4-79713

  This invention is made | formed in view of said subject, Comprising: It is providing the manufacturing method of a metal-clad laminated board which has productivity significantly higher than the conventional method.

  As a result of intensive studies in view of the above-mentioned problems, the present inventors have uniquely found a method for producing a metal-clad laminate having high productivity, and have completed the present invention. That is, this invention can solve the said subject with the following novel manufacturing methods.

  That is, the present invention is a method for producing a metal-clad laminate having at least two polyimide layers on a conductor, which is a solution selected from a solution containing a polyimide resin precursor or a solution containing a polyimide resin. A step of casting at least two kinds of solutions including a solution containing a precursor of at least one type of polyimide resin onto a conductor by coextrusion to form a plurality of layers of two or more layers. Among the solutions used in the above, a solution containing at least one polyimide resin precursor contains a chemical dehydrating agent and a catalyst, and relates to a method for producing a metal-clad laminate.

  In a preferred embodiment, the chemical dehydrating agent and the catalyst are used in an amount of 0.5 to 4.0 mol of chemical dehydrating agent with respect to 1 mol of amic acid unit in the polyamic acid contained in the solution containing the chemical dehydrating agent and catalyst. It is a 0.05-2.0 mol catalyst, It is related with the manufacturing method of the said metal-clad laminated board characterized by the above-mentioned.

  A more preferred embodiment relates to the method for producing a metal-clad laminate, wherein the polyimide layer comprises at least a high heat resistant polyimide layer and a thermoplastic polyimide layer.

  A more preferred embodiment relates to the method for producing a metal-clad laminate, wherein the polyimide layer is provided with a thermoplastic polyimide layer on both sides of the high heat-resistant polyimide layer.

  In a more preferred embodiment, the precursor solution of thermoplastic polyimide-precursor solution of high heat-resistant polyimide-precursor solution of thermoplastic polyimide is cast on the conductor by coextrusion in this order, and then dried. After firing, a laminate composed of a conductor-thermoplastic polyimide layer-high heat-resistant polyimide layer-thermoplastic polyimide layer is prepared, and then the thermoplastic polyimide layer on the side not in contact with the conductor of the laminate and the second It is related with the manufacturing method of the said metal-clad laminated board characterized by carrying out heat lamination of a conductor.

  According to the present invention, the productivity of the metal-clad laminate can be dramatically improved as compared with the conventional method, and as a result, the metal-clad laminate can be provided at a low cost.

  Embodiments of the present invention will be described below.

  The method for producing a metal-clad laminate according to the present invention is a method for producing a metal-clad laminate having at least two kinds of polyimide layers on a conductor, and a solution containing a polyimide resin precursor or a polyimide resin A solution selected from the group consisting of at least one polyimide resin precursor and a solution containing at least one polyimide resin precursor is cast on the conductor by coextrusion to form two or more layers. Among the solutions used for the coextrusion, a solution containing at least one polyimide resin precursor contains a chemical dehydrating agent and a catalyst.

  The polyimide layer is not particularly limited as long as it is two or more layers. Preferably, the polyimide layer is preferably at least two layers of a high heat resistant polyimide layer imparting dimensional stability and a thermoplastic polyimide layer imparting adhesiveness to the conductor. Preferably there is.

  Hereinafter, description will be given based on an example of the embodiment.

<High heat resistant polyimide layer>
The high heat resistant polyimide layer according to the present invention is not particularly limited in its molecular structure and thickness as long as it contains 90 wt% or more of a non-thermoplastic polyimide resin. The non-thermoplastic polyimide used for the high heat resistant polyimide layer is manufactured using polyamic acid as a precursor. Any known method can be used as a method for producing the polyamic acid, and usually, the aromatic tetracarboxylic dianhydride and the aromatic diamine are controlled by dissolving substantially equimolar amounts in an organic solvent. It is produced by stirring under temperature conditions until the polymerization of the acid dianhydride and diamine is completed. These polyamic acid solutions are usually obtained at a concentration of 5 to 35 wt%, preferably 10 to 30 wt%. When the concentration is in this range, an appropriate molecular weight and solution viscosity are obtained.

As the polymerization method, any known method and a combination thereof can be used. The characteristic of the polymerization method in the polymerization of polyamic acid is the order of addition of the monomers, and the physical properties of the polyimide obtained can be controlled by controlling the order of addition of the monomers. Therefore, in the present invention, any method of adding monomers may be used for the polymerization of polyamic acid. The following method is mentioned as a typical polymerization method. That is,
1) A method in which an aromatic diamine is dissolved in an organic polar solvent and this is reacted with a substantially equimolar amount of an aromatic tetracarboxylic dianhydride for polymerization.
2) An aromatic tetracarboxylic dianhydride is reacted with a small molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having acid anhydride groups at both ends. Then, the method of superposing | polymerizing using an aromatic diamine compound so that an aromatic tetracarboxylic dianhydride and an aromatic diamine compound may become substantially equimolar in all the processes.
3) An aromatic tetracarboxylic dianhydride and an excess molar amount of the aromatic diamine compound are reacted in an organic polar solvent to obtain a prepolymer having amino groups at both ends. Subsequently, after adding an aromatic diamine compound here, using the aromatic tetracarboxylic dianhydride so that the aromatic tetracarboxylic dianhydride and the aromatic diamine compound are substantially equimolar in all steps. How to polymerize.
4) A method in which an aromatic tetracarboxylic dianhydride is dissolved and / or dispersed in an organic polar solvent and then polymerized using an aromatic diamine compound so as to be substantially equimolar.
5) A method in which a substantially equimolar mixture of aromatic tetracarboxylic dianhydride and aromatic diamine is reacted in an organic polar solvent for polymerization.
And so on. These methods may be used singly or in combination.

  In the present invention, the polyamic acid obtained by using any of the above polymerization methods may be used, and the polymerization method is not particularly limited.

  In this invention, it is also preferable to use the polymerization method which obtains a prepolymer using the diamine component which has a rigid structure mentioned later. By using this method, a polyimide film having a high elastic modulus and a small hygroscopic expansion coefficient tends to be easily obtained. The molar ratio of the diamine having a rigid structure and the acid dianhydride used in preparing the prepolymer in the present method is 100: 70 to 100: 99 or 70: 100 to 99: 100, and further 100: 75 to 100: 90 or 75: 100-90: 100 is preferable. When this ratio is less than the above range, it is difficult to obtain the effect of improving the elastic modulus and the hygroscopic expansion coefficient, and when it exceeds the above range, there are cases where the linear expansion coefficient becomes too small or the tensile elongation becomes small.

  Here, the material used for the polyamic acid composition concerning this invention is demonstrated.

  Suitable tetracarboxylic dianhydrides that can be used in the present invention are pyromellitic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetra. Carboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′- Benzophenone tetracarboxylic dianhydride, 4,4′-oxyphthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,4,9,10-perylenetetracarboxylic acid Dianhydride, bis (3,4-dicarboxyphenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxy) Phenyl) eta Dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride, oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) Sulfone dianhydride, p-phenylenebis (trimellitic acid monoester acid anhydride), ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (trimellitic acid monoester acid anhydride) and the like These can be used alone or in a mixture of any proportion.

  Among these acid dianhydrides, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 4,4′-oxyphthalic dianhydride, 3,3 ′ It is preferable to use at least one selected from 4,4'-biphenyltetracarboxylic dianhydride.

  Among these acid dianhydrides, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-oxyphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetra The preferred amount of use in the case of using at least one selected from carboxylic dianhydrides is 60 mol% or less, preferably 55 mol% or less, more preferably 50 mol% or less, based on the total acid dianhydrides. 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-oxyphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride When using at least one kind, if the amount used exceeds this range, the glass transition temperature of the polyimide film may become too low, or the storage elastic modulus at the time of heating may become too low, making film formation itself difficult. Therefore, it is not preferable.

  Moreover, when using pyromellitic dianhydride, the preferable usage-amount is 40-100 mol%, More preferably, it is 45-100 mol%, Most preferably, it is 50-100 mol%. By using pyromellitic dianhydride in this range, the glass transition temperature and the storage elastic modulus at the time of heating can be easily maintained in a range suitable for use or film formation.

  Suitable diamines that can be used in the polyamic acid composition that is a precursor of the non-thermoplastic polyimide according to the present invention include 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane, benzidine, and 3,3 ′. -Dichlorobenzidine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'- Diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 4,4′-oxydianiline, 3,3′-oxydianiline, 3,4′-oxydianiline, 1,5-diaminonaphthalene, 4,4 '-Diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'- Aminodiphenylethylphosphine oxide, 4,4′-diaminodiphenyl N-methylamine, 4,4′-diaminodiphenyl N-phenylamine, 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene, 1,2-diaminobenzene, bis {4- (4-aminophenoxy) phenyl} sulfone, bis {4- (4-aminophenoxy) phenyl} propane, bis {4- (3-aminophenoxy) phenyl} sulfone, 4 , 4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) ) Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-amino) Phenoxy) benzene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone and the like.

  As the diamine component, a diamine having a rigid structure and an amine having a flexible structure can be used in combination, and the preferred use ratio in that case is 80/20 to 20/80, more preferably 70/30 to 30/70, in molar ratio. Particularly, it is 60/40 to 30/70. If the use ratio of the rigid diamine exceeds the above range, the tensile elongation of the resulting film tends to be small, and if it falls below this range, the glass transition temperature becomes too low or the storage modulus during heat decreases. In some cases, the film formation is difficult, and it may be harmful.

  In the present invention, the diamine having a rigid structure is the following general formula (1).

（ただし、式中のＲ₂は、下記一般式群（１）

(In the formula, R ₂ represents the following general formula group (1)

で表される２価の芳香族基からなる群から選択される基であり、式中のＲ₃は同一または異なっていてもよく、Ｈ−、ＣＨ₃−、−ＯＨ、−ＣＦ₃、−ＳＯ₄、−ＣＯＯＨ、−ＣＯ-ＮＨ₂、Ｃｌ−、Ｂｒ−、Ｆ−及びＣＨ₃Ｏ−からなる群より選択される何れかの１つの基である。）
で表されるものをいう。

R _{3 in} the formula may be the same or different, and H—, CH ₃ —, —OH, —CF ₃ , — One group selected from the group consisting of SO ₄ , —COOH, —CO—NH ₂ , Cl—, Br—, F— and CH ₃ O—. )
The one represented by

  The diamine having a flexible structure is a diamine having a flexible structure such as an ether group, a sulfone group, a ketone group, or a sulfide group, and is preferably represented by the following general formula (2).

（ただし、式中のＲ₄は、下記一般式群（２）

(In the formula, R ₄ represents the following general formula group (2)

で表される２価の有機基からなる群から選択される基であり、式中のＲ₅は同一または異なっていてもよく、Ｈ−、ＣＨ₃−、−ＯＨ、−ＣＦ₃、−ＳＯ₄、−ＣＯＯＨ、−ＣＯ-ＮＨ₂、Ｃｌ−、Ｂｒ−、Ｆ−及びＣＨ₃Ｏ−からなる群より選択される何れかの１つの基である。）
本発明において用いられる高耐熱性ポリイミド層は、上記の範囲の中で所望の特性を有するように適宜芳香族酸二無水物および芳香族ジアミンの種類、配合比を決定して用いることにより得ることができる。

In a divalent radical selected from the group consisting of organic groups represented, R ₅ in the formula may be the same or _{different, H-, CH 3 -, -} OH, -CF 3, -SO ₄ , any one group selected from the group consisting of —COOH, —CO—NH ₂ , Cl—, Br—, F— and CH ₃ O—. )
The high heat-resistant polyimide layer used in the present invention is obtained by appropriately determining the type and blending ratio of aromatic dianhydride and aromatic diamine so as to have desired characteristics within the above range. Can do.

  As the preferred solvent for synthesizing the polyamic acid, any solvent can be used as long as it dissolves the polyamic acid. However, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N- Examples thereof include methyl-2-pyrrolidone, and N, N-dimethylformamide and N, N-dimethylacetamide can be particularly preferably used.

  In addition, a filler can be added for the purpose of improving various film properties such as slidability, thermal conductivity, conductivity, corona resistance, and loop stiffness. Any filler may be used, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica and the like.

The particle size of the filler is not particularly limited because it is determined by the film characteristics to be modified and the kind of filler to be added, but generally the average particle size is 0.05 to 100 μm, preferably 0.1. It is -75 micrometers, More preferably, it is 0.1-50 micrometers, Most preferably, it is 0.1-25 micrometers. If the particle size is below this range, the modification effect is less likely to appear. If the particle size is above this range, the surface properties may be greatly impaired or the mechanical properties may be greatly deteriorated. Further, the number of added parts of the filler is not particularly limited because it is determined by the film properties to be modified, the filler particle diameter, and the like. Generally, the addition amount of the filler is 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, and more preferably 0.02 to 80 parts by weight with respect to 100 parts by weight of the polyimide. If the amount of filler added is less than this range, the effect of modification by the filler hardly appears, and if it exceeds this range, the mechanical properties of the film may be greatly impaired. Addition of filler
1. 1. A method of adding to a polymerization reaction solution before or during polymerization 2. A method of kneading fillers using three rolls after the completion of polymerization. Any method such as preparing a dispersion containing filler and mixing it with a polyamic acid organic solvent solution may be used, but a method of mixing a dispersion containing filler with a polyamic acid solution, particularly immediately before film formation. This method is preferable because the contamination by the filler in the production line is minimized. When preparing a dispersion containing a filler, it is preferable to use the same solvent as the polymerization solvent for the polyamic acid. Further, in order to disperse the filler satisfactorily and stabilize the dispersion state, a dispersant, a thickener and the like can be used within a range not affecting the film physical properties.

  The solution containing the precursor of the non-thermoplastic polyimide resin thus obtained is also referred to as a solution containing a precursor of high heat resistant polyimide.

<Thermoplastic polyimide layer>
The thermoplastic polyimide layer according to the present invention has a thermoplastic polyimide resin content and molecular structure contained in the layer as long as desired properties such as a significant adhesive force with a conductor and a suitable linear expansion coefficient are expressed. The thickness is not particularly limited. However, it is preferable that substantially 50 wt% or more of the thermoplastic polyimide resin is substantially contained in order to exhibit desired properties such as a significant adhesive force and a suitable linear expansion coefficient.

  As the thermoplastic polyimide contained in the thermoplastic polyimide layer, thermoplastic polyimide, thermoplastic polyamideimide, thermoplastic polyetherimide, thermoplastic polyesterimide and the like can be suitably used. Among these, thermoplastic polyesterimide is particularly preferably used from the viewpoint of low moisture absorption characteristics.

  The thermoplastic polyimide contained in the thermoplastic polyimide layer according to the present invention is obtained by a conversion reaction from the precursor polyamic acid. As the method for producing the polyamic acid, any known method can be used as in the precursor of the high heat resistant polyimide layer.

  Further, considering that it exhibits a significant adhesive force with the conductor layer and does not impair the heat resistance of the resulting metal-clad laminate, the thermoplastic polyimide in the present invention is glass in the range of 150 to 300 ° C. It preferably has a transition temperature (Tg). In addition, Tg can be calculated | required from the value of the inflexion point of the storage elastic modulus measured with the dynamic viscoelasticity measuring apparatus (DMA).

  The polyamic acid that is a precursor of the thermoplastic polyimide used in the present invention is not particularly limited, and any known polyamic acid can be used. Regarding the production of the polyamic acid solution, the raw materials and the production conditions can be used in exactly the same manner.

  The properties of thermoplastic polyimide can be adjusted by combining various raw materials to be used, but generally the glass transition temperature becomes higher and / or the storage elastic modulus during heat when the ratio of rigid diamine is increased. Is unfavorable because it increases the adhesion and processability. The diamine ratio of the rigid structure is preferably 40 mol% or less, more preferably 30 mol% or less, and particularly preferably 20 mol% or less.

  Specific examples of preferable thermoplastic polyimide resins include those obtained by polymerization reaction of acid dianhydrides including biphenyltetracarboxylic dianhydrides and diamines having aminophenoxy groups.

  Furthermore, for the purpose of controlling the properties of the adhesive film according to the present invention, inorganic or organic fillers, and other resins may be added as necessary.

<Manufacture of metal-clad laminates>
The method for obtaining the metal-clad laminate according to the present invention must be a coextrusion method. The co-extrusion method according to the present invention includes, for example, a solution containing a precursor of a high heat resistant polyimide and a solution containing a thermoplastic polyimide or a solution containing a precursor of a thermoplastic polyimide. And simultaneously extruding both solutions as at least two layers of thin film from the outlet of the multilayer die. To describe a generally used method, both solutions extruded from two or more multilayer dies are continuously extruded onto a conductor held in a backup roll, and then a multilayer thin film on the support. By volatilizing at least a part of the solvent in the form and further sufficiently heat-treating at a high temperature (250-600 ° C.), the solvent is substantially removed and imidization proceeds, so that the target metal-clad laminate is obtained. A board is obtained. Further, for the purpose of improving the melt fluidity of the adhesive layer, the imidization rate may be intentionally lowered and / or the solvent may be left.

  The conductor according to the present invention is not limited as long as it is a metal foil, but is preferably a copper foil, particularly a copper foil having a thickness of 5 to 20 μm, or an ultrathin copper foil with a carrier copper foil. As the copper foil, either a rolled copper foil or an electrolytic copper foil can be suitably used, and any known treatment can be used for the surface treatment of the copper foil.

  In general, polyimide is obtained by a dehydration conversion reaction from a polyimide precursor, that is, a polyamic acid. As a method for performing the conversion reaction, a thermal curing method performed only by heat and a chemical curing method using a chemical curing agent are used. The two methods are most widely known. However, in the present invention, it is essential to employ a chemical curing method.

  Here, the chemical curing agent includes a chemical dehydrating agent and a catalyst. The chemical dehydrating agent here is a dehydrating ring-closing agent for polyamic acid, and as its main component, aliphatic acid anhydride, aromatic acid anhydride, N, N'-dialkylcarbodiimide, lower aliphatic halide, halogen A lower aliphatic acid anhydride, an arylsulfonic acid dihalide, a thionyl halide, or a mixture of two or more thereof can be preferably used. Of these, aliphatic acid anhydrides and aromatic acid anhydrides work particularly well. A suitable introduction amount of the chemical dehydrating agent is 0.5 to 4.0 mol, preferably 0.7 to 4.0, relative to 1 mol of the amic acid unit in the polyamic acid contained in the solution containing the chemical dehydrating agent. Mol, particularly preferably 1.0 to 4.0 mol. If the above range is exceeded, the conductor may corrode. On the other hand, below the above range, the curing rate is not sufficient and the effects of the present invention may not be exhibited.

  The catalyst is a component having an effect of promoting the dehydration ring-closing action of the chemical dehydrating agent on the polyamic acid. For example, an aliphatic tertiary amine, an aromatic tertiary amine, or a heterocyclic tertiary amine is used. it can. Of these, nitrogen-containing heterocyclic compounds such as imidazole, benzimidazole, isoquinoline, quinoline, or β-picoline are preferred. Furthermore, introduction of an organic polar solvent into a solution composed of a chemical dehydrating agent and a catalyst can be appropriately selected. A suitable introduction amount of the catalyst is 0.05 to 2.0 mol, preferably 0.1 to 2.0 mol, particularly preferably 0.1 mol to 1 mol of amic acid unit in the polyamic acid contained in the solution containing the catalyst. Is 0.2 to 2.0 mol. When the above range is exceeded, the catalyst may remain in the polyimide layer and may be inferior in long-term heat resistance. On the other hand, below the above range, the curing rate is not sufficient and the effects of the present invention may not be exhibited.

  The polyimide precursor for introducing the chemical curing agent can suitably express the effect of the present invention regardless of which layer is formed, but the method of introducing the chemical curing agent only in the high heat-resistant polyimide layer, The most favorable results can be obtained with respect to simplification of the apparatus, prevention of corrosion of the conductor, and physical properties of the polyimide layer.

  There is no particular limitation regarding the method of volatilization of the solvent in the precursor solution of the high heat-resistant polyimide extruded from the multilayer die having two or more layers and the solution containing the thermoplastic polyimide or the solution containing the precursor of the thermoplastic polyimide. The method using heating and / or blowing is the simplest method. When the temperature at the time of heating is too high, the solvent is volatilized rapidly, and the trace of the volatilization causes a micro defect to be formed in the finally obtained adhesive film. Preferably there is.

  As for the imidization time, it suffices to take a sufficient time for the imidization and drying to be substantially completed, and although it is not uniquely limited, generally it is appropriately set within a range of about 1 to 600 seconds. Is done.

  As the above-mentioned multilayer die having two or more layers, those having various structures can be used. For example, a T die for forming a film for a plurality of layers can be used. In addition, any conventionally known structure can be suitably used, and feed block T dies and multi-manifold T dies are exemplified as particularly suitable ones.

  Moreover, it can also be preferably selected to provide a conductor on both sides of the polyimide layer by thermally laminating the second conductor with the thermoplastic polyimide layer on the side not in contact with the conductor of the obtained metal-clad laminate. The second conductor according to the present invention is not limited as long as it is a metal foil like the conductor, but is a copper foil, particularly a copper foil with a thickness of 5 to 20 μm, or an ultrathin copper foil with a carrier copper foil. It is preferable. As the copper foil, either a rolled copper foil or an electrolytic copper foil can be suitably used, and any known treatment can be used for the surface treatment of the copper foil.

  The method of thermal lamination is not particularly limited, and examples thereof include a double belt method and a hot roll method in which pressure is applied with a pair of hot rolls. Also in the hot roll method, a method of sandwiching a protective film between the hot roll and the metal-clad laminate, a method of surrounding the hot roll with a booth, and filling the inside of the booth with an inert gas can be mentioned.

Next, the manufacturing method of the adhesive film which concerns on this invention is demonstrated in detail by an Example.

(Synthesis Example 1; Synthesis of Polyamic Acid as Precursor of High Heat-Resistant Polyimide)
239 kg of N, N-dimethylformamide (hereinafter also referred to as DMF) cooled to 10 ° C., 6.9 kg of 4,4′-oxydianiline (hereinafter also referred to as ODA), p-phenylenediamine (hereinafter also referred to as p-PDA) After dissolving 9.4 kg of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (hereinafter also referred to as BAPP) 6.2 kg, pyromellitic dianhydride (hereinafter also referred to as PMDA). ) 10.4 kg was added and dissolved by stirring for 1 hour. To this, 20.3 kg of benzophenone tetracarboxylic dianhydride (hereinafter also referred to as BTDA) was added and dissolved by stirring for 1 hour.

  A separately prepared DMF solution of PMDA (PMDA: DMF = 0.9 kg: 7.0 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3500 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution of a precursor of a high heat resistant polyimide compound having a solid content concentration of 18% by weight and a rotational viscosity at 23 ° C. of 3500 poise.

(Synthesis Example 2; Synthesis of Polyamic Acid as Precursor of Thermoplastic Polyimide)
To a 300 L reaction vessel, 78 kg of DMF and 11.56 kg of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) were added, and while stirring under a nitrogen atmosphere, 3,3′4,4 7.87 kg of '-biphenyltetracarboxylic dianhydride (BPDA) was gradually added. Subsequently, 0.38 kg of ethylenebis (trimellitic acid monoester acid anhydride) (TMEG) was added and stirred for 30 minutes in an ice bath. A solution prepared by dissolving 0.2 kg of TMEG in 4 kg of DMF was separately prepared, and this was gradually added to the above reaction solution while paying attention to the viscosity and stirred. When the viscosity reached 3300 poise, addition and stirring were stopped to obtain a polyamic acid solution as a precursor of a thermoplastic polyimide compound.

Example 1
The following chemical dehydrating agent and catalyst were contained in the polyamic acid solution of the precursor of the high heat-resistant polyimide obtained in Synthesis Example 1.
Chemical dehydrating agent: 2.0 mol per 1 mol of polyamic acid amic acid unit which is acetic anhydride as precursor of high heat-resistant polyimide Catalyst: Amido acid unit of polyamic acid which is isoquinoline as precursor of high heat-resistant polyimide 0.5 mol per mol Next, from the multi-manifold type three-layer coextrusion multilayer die having a lip width of 520 mm, both outer layers are the polyamic acid solution of the precursor of the thermoplastic polyimide obtained in Synthesis Example 2, and the inner layer is A multilayer film having a three-layer structure formed in the order of becoming a polyamic acid solution as a precursor of a high heat-resistant polyimide solution is continuously extruded, and on a mat surface of a copper foil running 50 mm below the T die. Casted. As the copper foil, a copper foil USLP-SE made by Nippon Electrolytic Co., Ltd. having a thickness of 12 μm was used. Next, the multilayered copper foil was dried at 130 ° C. for 100 seconds, then dried and imidized at 300 ° C. for 16 seconds, 400 ° C. for 29 seconds, and 450 ° C. for 17 seconds in a tenter furnace. A metal-clad laminate having a good shape with a plastic polyimide layer of 2 μm and a high heat-resistant polyimide layer of 10 μm was obtained.

  The thermoplastic polyimide layer on the side of the obtained metal-clad laminate, to which the copper foil was not bonded, and a 12 μm thick copper foil USLP-SE made by Nippon Electrolytic Co., Ltd. were pressure-bonded using a hot roll. The pressure bonding conditions were as follows: protective material (Apical 125 NPI; manufactured by Kaneka Corporation) was used on both sides of the heat roll and the metal-clad laminate, laminating temperature 380 ° C., laminating pressure 30 N / cm, laminating speed 1.5 m / min. did.

  The obtained metal-clad laminate had good appearance.

(Example 2)
A metal-clad laminate was produced in the same manner as in Example 1 except that 18 μ-thick Japan Energy rolled copper foil BHY-22BT was used as the conductor and the second conductor.

  The obtained metal-clad laminate had good appearance.

(Comparative Example 1)
An attempt was made to produce a metal-clad laminate by the same means as in Example 1 except that no chemical dehydrating agent and catalyst were used. However, the polyamic acid solution is not sufficiently dried at the exit of the tenter furnace. A metal-clad laminate could not be obtained.

Claims (5)

  A method for producing a metal-clad laminate having at least two polyimide layers on a conductor, wherein the solution is selected from a solution containing a polyimide resin precursor or a solution containing a polyimide resin, and at least one kind Including a step of forming a plurality of two or more layers by coextrusion of at least two or more kinds of solutions including a solution containing a polyimide resin precursor, and among the solutions used for the coextrusion, A method for producing a metal-clad laminate, wherein a solution containing at least one polyimide resin precursor contains a chemical dehydrating agent and a catalyst.   The chemical dehydrating agent and the catalyst are added in an amount of 0.5 to 4.0 mol of chemical dehydrating agent and 0.05 to 2 with respect to 1 mol of amic acid unit in the polyamic acid contained in the solution containing the chemical dehydrating agent and the catalyst. The method for producing a metal-clad laminate according to claim 1, wherein the catalyst is 0.0 mol of catalyst.   The method for producing a metal-clad laminate according to claim 1, wherein the polyimide layer comprises at least a high heat resistant polyimide layer and a thermoplastic polyimide layer.   The method for producing a metal-clad laminate according to any one of claims 1 to 3, wherein the polyimide layer is provided with a thermoplastic polyimide layer on both sides of the high heat-resistant polyimide layer.   On the conductor, a precursor solution of a thermoplastic polyimide-a precursor solution of a highly heat-resistant polyimide-a precursor solution of a thermoplastic polyimide is cast on the conductor by coextrusion in the above order, and then dried and fired. After producing a laminate comprising a thermoplastic polyimide layer, a high heat resistance polyimide layer, and a thermoplastic polyimide layer, the thermoplastic polyimide layer on the side not in contact with the conductor of the laminate and the second conductor are thermally laminated. The method for producing a metal-clad laminate according to claim 1, wherein: