JP4551094B2 - Adhesive film, flexible metal-clad laminate with improved dimensional stability obtained therefrom, and method for producing the same - Google Patents

Description

  The present invention relates to an adhesive film provided with an adhesive layer on at least one surface of an insulating film, a flexible metal-clad laminate obtained by bonding a metal foil to the adhesive film with a hot roll laminator, and a method for producing the same.

  In recent years, the demand for various printed circuit boards has increased with the reduction in weight, size and density of electronic products, and in particular, the demand for flexible laminates (also referred to as flexible printed wiring boards (FPC), etc.) has increased. ing. 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. As the adhesive material, a thermosetting adhesive such as epoxy or acrylic is generally used (FPC using these thermosetting adhesives is hereinafter also referred to as three-layer FPC).

  Thermosetting adhesives have the advantage that they can be bonded at relatively low temperatures. However, in the future, as required characteristics such as heat resistance, flexibility, and electrical reliability become stricter, it is considered that it is difficult to cope with a three-layer FPC using a thermosetting adhesive. On the other hand, an FPC (hereinafter also referred to as a two-layer FPC) in which a metal layer is directly provided on an insulating film or a thermoplastic polyimide is used for an adhesive layer has been proposed. This two-layer FPC has characteristics superior to those of the three-layer FPC, and demand is expected to increase in the future.

  As a method for producing a flexible metal-clad laminate for use in a two-layer FPC, a polyamic acid, which is a polyimide precursor, is cast on a metal foil, applied, and then casted directly onto a polyimide film by sputtering or plating. Examples thereof include a metallizing method for providing a metal layer and a laminating method for bonding a polyimide film and a metal foil through a thermoplastic polyimide. Among these, the lamination method is superior in that the thickness range of the metal foil that can be handled is wider than that of the casting method and the apparatus cost is lower than that of the metalizing method. As a device for laminating, a hot roll laminating device or a double belt press device for continuously laminating a roll-shaped material is used. Of these, the hot roll laminating method can be used more preferably from the viewpoint of productivity.

  When a conventional three-layer FPC was produced by a laminating method, a thermosetting resin was used for the adhesive layer, so that the laminating temperature could be less than 200 ° C. (see Patent Document 1). On the other hand, since the two-layer FPC uses thermoplastic polyimide as an adhesive layer, it is necessary to apply a high temperature of 200 ° C. or higher, and in some cases, close to 400 ° C., in order to develop heat-fusibility. Therefore, residual distortion occurs in the flexible metal-clad laminate obtained by laminating, and it appears as a dimensional change when wiring is formed by etching and when solder reflow is performed to mount components.

  In particular, in the laminating method, when an adhesive layer containing a thermoplastic polyimide is provided on a polyimide film, the polyamic acid which is a precursor of the thermoplastic polyimide is cast and applied, and then continuously heated to imidize, Since the heating and pressurization is continuously performed when the metal foil is bonded, the material is often placed in a heating environment under tension. Therefore, different thermal stresses are generated in the longitudinal direction (hereinafter also referred to as MD direction) and in the width direction (hereinafter also referred to as TD direction). Specifically, a pulling force acts in the MD direction where tension is applied, and conversely, a shrinking force acts in the TD direction. As a result, when the metal foil is etched from the flexible laminate and when heated through solder reflow, this strain is released, the MD direction contracts, and conversely, the TD direction expands.

  In recent years, in order to achieve miniaturization and weight reduction of electronic devices, wiring provided on a substrate has been miniaturized, and components to be mounted are mounted with miniaturization and high density. For this reason, if the dimensional change after forming the fine wiring is increased, there is a problem that the component and the board are not well connected due to deviation from the component mounting position in the design stage.

Therefore, attempts have been made to suppress dimensional changes by controlling the laminating pressure or controlling the tension of the adhesive film (see Patent Document 2 or 3). However, although the dimensional change is improved by these means, it is not sufficient yet, and further improvement of the dimensional change is demanded.
JP-A-9-199830 JP 2002-326308 A JP 2002-326280 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an adhesive film from which a flexible metal-clad laminate in which the occurrence of dimensional change is suppressed when produced by a laminating method, and a metal It is an object of the present invention to provide a flexible metal-clad laminate obtained by laminating foil, particularly a flexible metal-clad laminate capable of suppressing the occurrence and variation of dimensional changes when produced by a laminating method, and a method for producing the same.

  As a result of intensive studies in view of the above problems, the present inventors have appropriately determined both the storage elastic modulus decrease start temperature of the insulating film to be the core film and the storage elastic modulus of the insulating film at the metal foil bonding temperature. The inventors have independently found out that the dimensional change rate and the variation of the obtained flexible metal-clad laminate can be improved by controlling and further appropriately controlling the heat laminating conditions, and completed the present invention.

  That is, the first of the present invention is an adhesive film for a flexible metal-clad laminate in which an adhesive layer is provided on at least one surface of the insulating film, and the storage elastic modulus lowering start temperature of the insulating film is 250 ° C. or higher, and It is related with the adhesive film characterized by the storage elastic modulus of the insulating film in metal foil bonding temperature being 0.01 G-1.0 GPa.

  A preferred embodiment relates to the adhesive film as described above, wherein the adhesive layer contains a thermoplastic polyimide.

  Furthermore, a preferable embodiment relates to the adhesive film described above, which can be bonded to a metal foil at a temperature of 300 ° C. or higher.

  A second aspect of the present invention relates to a method for producing a flexible metal-clad laminate, wherein a metal foil is bonded to the adhesive film using a hot roll laminator having a pair of metal rolls.

  A preferred embodiment relates to the above production method, wherein a polyimide film having a thickness of 75 μm or more is disposed as a protective material between a heating roll and a metal foil, and the adhesive film and the metal foil are bonded together.

  Further preferred embodiment is characterized in that after bonding the adhesive film and the metal foil, the protective material is placed on the outside of the metal foil, and the heating roll is brought into contact for 0.1 second or more. It relates to the manufacturing method.

  In a more preferred embodiment, after bonding the adhesive film and the metal foil, the protective material is still placed on the outside of the metal foil under a tension of 1 to 10 N / cm (lamination temperature -200 ° C.) The present invention relates to the above production method, wherein post-heating treatment is performed in a temperature atmosphere of (lamination temperature + 100 ° C.).

  The third aspect of the present invention is the dimensional change rate before and after removing the metal foil, and the total value of the dimensional change rate before and after performing heat treatment at 250 ° C. for 30 minutes after removing the metal foil. The present invention relates to a flexible metal-clad laminate characterized by being in the range of -0.05 to + 0.05% in both the MD direction and the TD direction.

  A preferred embodiment is that when the standard deviation of the dimensional change rate before and after removing the metal foil and the total value of the dimensional change rate before and after performing heat treatment at 250 ° C. for 30 minutes after removing the metal foil is σ, The flexible metal-clad laminate is characterized in that 3σ is 0.02 or less in the TD direction.

  According to the present invention, the dimensional stability of a flexible metal-clad laminate, particularly a flexible metal-clad laminate produced by a laminating method, can be improved. Specifically, the dimensional change rate before and after removing the metal foil, and the dimensional change rate before and after performing heat treatment at 250 ° C. for 30 minutes after the metal foil removal, and the variation in the dimensional change rate can be reduced. Further, it can be suitably used for an FPC or the like in which fine wiring is formed, and problems such as misalignment can be improved.

  One embodiment of the present invention will be described below.

  The adhesive film according to the present invention is characterized in that an adhesive layer is provided on at least one surface of the insulating film.

  As the insulating film used in the present invention, any film such as a polyimide film, a polyester film, a liquid crystal polymer film, a nylon film, an aramid film, and a polyamideimide film may be used, but a polyimide film from the viewpoint of heat resistance and insulating characteristics. Is preferably used.

  Hereinafter, the case where a polyimide film is used as the insulating film will be described based on an example of the embodiment.

  The polyimide film used in the present invention is manufactured using polyamic acid as a precursor. Any known method can be used as a method for producing the polyamic acid. Usually, the polyamic acid obtained by dissolving a substantially equimolar amount of an aromatic dianhydride and an aromatic diamine in an organic solvent is obtained. The organic solvent solution is produced by stirring under controlled temperature conditions until the polymerization of the acid dianhydride and the 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 of polymerizing by reacting a substantially equimolar mixture of aromatic tetracarboxylic dianhydride and aromatic diamine in an organic polar solvent.
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 the present invention, it is also preferable to use a polymerization method for obtaining a prepolymer using a diamine component having a rigid structure typified by paraphenylenediamine or substituted benzidine. 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 acid dianhydrides that can be used in the present invention are pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid. Dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetra Carboxylic dianhydride, 4,4′-oxyphthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride , Bis (3,4-dicarboxyphenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) Ethane dianhydride, bi (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride, oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, including 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 preferably used alone or in any desired mixture.

  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 polyimide precursor polyamic acid composition according to the present invention include 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane, benzidine, 3,3′-dichlorobenzidine, 3, 3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenylsulfone, 4, 4'-diaminodiphenyl sulfone, 4,4'-oxydianiline, 3,3'-oxydianiline, 3,4'-oxydianiline, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyldiethylsilane 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenyl Tylphosphine 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- (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-aminophenoxy) benzene, 3,3′-diaminobenzophenone, 4,4′-diamy Benzophenone and their analogs thereof.

  The polyimide film used in the present invention is obtained by appropriately determining the type and blending ratio of the aromatic dianhydride and aromatic diamine so as to be a film having 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.

  A conventionally well-known method can be used about the method of manufacturing a polyimide film from these polyamic acid solutions. This method includes a thermal imidization method and a chemical imidization method, and either method may be used to produce a film, but the imidization by the chemical imidation method is more preferably used in the present invention. It tends to be easy to obtain a polyimide film having various characteristics.

In addition, the production process of the polyimide film particularly preferable in the present invention is as follows.
a) a step of reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride in an organic solvent to obtain a polyamic acid solution;
b) casting a film-forming dope containing the polyamic acid solution on a support;
c) a step of peeling the gel film from the support after heating on the support;
d) further heating to imidize and dry the remaining amic acid,
It is preferable to contain.

  In the above step, a curing agent containing a dehydrating agent typified by an acid anhydride such as acetic anhydride and an imidation catalyst typified by a tertiary amine such as isoquinoline, β-picoline or pyridine may be used. .

  Hereafter, the manufacturing process of a polyimide film is demonstrated taking the preferable one form of this invention and a chemical imide method as an example. However, the present invention is not limited to the following examples. The film forming conditions and heating conditions can vary depending on the type of polyamic acid, the thickness of the film, and the like.

A film forming dope is obtained by mixing a dehydrating agent and an imidization catalyst in a polyamic acid solution at a low temperature. Subsequently, this film-forming dope is cast into a film on a support such as a glass plate, an aluminum foil, an endless stainless steel belt, or a stainless drum, and the temperature on the support is 80 ° C. to 200 ° C., preferably 100 ° C. to 180 ° C. By heating in the region, the dehydrating agent and imidization catalyst are activated to partially cure and / or dry, and then peel from the support to obtain a polyamic acid film (hereinafter referred to as gel film).
The gel film is in the intermediate stage of curing from polyamic acid to polyimide, has self-supporting properties, and has the formula (1)
(AB) × 100 / B (1)
In formula (1), A and B represent the following.
A: Weight of gel film B: The volatile content calculated from the weight after heating the gel film at 450 ° C. for 20 minutes is in the range of 5 to 500% by weight, preferably 5 to 200% by weight, more preferably 5 to 5%. It is in the range of 150% by weight. It is preferable to use a film in this range, and problems such as film breakage, uneven film color due to drying unevenness, and characteristic variations may occur during the baking process.

  The preferable amount of the dehydrating agent is 0.5 to 5 mol, preferably 1.0 to 4 mol, relative to 1 mol of the amic acid unit in the polyamic acid. Moreover, the preferable quantity of an imidation catalyst is 0.05-3 mol with respect to 1 mol of amic acid units in a polyamic acid, Preferably it is 0.2-2 mol.

  If the dehydrating agent and the imidization catalyst are below the above ranges, chemical imidization may be insufficient, and may break during firing or mechanical strength may decrease. Moreover, when these amounts exceed the above range, the progress of imidization becomes too fast, and it may be difficult to cast into a film, which is not preferable.

  The end of the gel film is fixed to avoid shrinkage during curing, water, residual solvent, residual conversion agent and catalyst are removed, and the remaining amic acid is completely imidized to obtain the present invention. A polyimide film is obtained.

  At this time, it is preferable to finally heat at a temperature of 400 to 650 ° C. for 5 to 400 seconds. Above this temperature and / or for a long time, the film may suffer from thermal degradation and may cause problems. Conversely, if the temperature is lower than this temperature and / or the time is shorter, the predetermined effect may not be exhibited.

  Moreover, in order to relieve the internal stress remaining in the film, heat treatment can be performed under the minimum tension necessary for transporting the film. This heat treatment may be performed in the film manufacturing process, or may be provided separately. The heating conditions vary depending on the characteristics of the film and the apparatus used, and therefore cannot be determined in general. However, it is generally 200 ° C. or higher and 500 ° C. or lower, preferably 250 ° C. or higher and 500 ° C. or lower, particularly preferably 300 ° C. or higher. The internal stress can be relaxed by heat treatment at a temperature of 450 ° C. or lower for 1 to 300 seconds, preferably 2 to 250 seconds, particularly preferably 5 to 200 seconds.

Control of various properties of the polyimide film can be appropriately controlled according to the type of monomer used, the order of addition of the monomers during polymerization, the imidization method to be selected, etc., but in the present invention, the molecular design generally has the following properties. It is preferable to do.
1. The tensile elastic modulus is 4.0 GPa or more, preferably 4.5 GPa or more, particularly preferably 5.0 GPa or more. 2. Hygroscopic expansion coefficient is 20 ppm or less, preferably 16 ppm or less. The linear expansion coefficient is 1-20 ppm, preferably 5-18 ppm
In particular, the polyimide film according to the present invention has a storage elastic modulus lowering start temperature of 250 ° C. or higher and a storage elastic modulus at a metal foil bonding temperature of 0.01 to 1.0 GPa, after removing the copper foil and 250 It becomes possible to obtain a flexible metal-clad laminate excellent in dimensional stability after heating at 30 ° C. for 30 minutes.

  Specifically, MD /, which has a storage elastic modulus lowering start temperature and has a storage elastic modulus at a metal foil laminating temperature in the range of 0.01 to 1.0 GPa, is particularly prominently generated by the laminating method. Residual strain of TD can be alleviated, and the occurrence of dimensional change after removal of the metal foil and after heating can be suppressed. The storage elastic modulus decrease start temperature here indicates a storage elastic modulus inflection point when the storage elastic modulus of the polyimide film is measured. The storage modulus inflection point can be obtained by dynamic viscoelasticity measurement (DMA). Further, by setting the storage elastic modulus decrease start temperature to 250 ° C. or higher, it is possible to suppress the occurrence of dimensional change after heating, particularly after high temperature heating of 250 ° C. for 30 minutes.

  When the core polyimide film does not have a storage elastic modulus lowering start temperature, or when the storage elastic modulus at the metal foil bonding temperature is outside the above range, MD / TD residual strain generated during lamination is sufficiently relaxed It may not be possible to suppress the occurrence of dimensional changes. On the other hand, when the storage elastic modulus lowering start temperature is lower than 250 ° C., the polyimide film as the core is softened during the solder reflow or solder dipping process, so that the occurrence of dimensional change may not be suppressed.

  That is, by appropriately controlling both the storage elastic modulus decrease start temperature and the storage elastic modulus at the metal foil laminating temperature, the wiring pattern forming process by etching the metal foil layer and the dimensional change in the solder reflow or solder dipping process. It is possible to suppress the occurrence of defects.

  The adhesive layer used in the present invention may be any of acrylic, epoxy, modified epoxy, phenol, polyamideimide, polyimide, but from the viewpoint of heat resistance, insulation reliability, and laminate processability. It is preferable to use an adhesive layer containing thermoplastic polyimide.

  As the thermoplastic polyimide contained in the adhesive layer, thermoplastic polyimide, thermoplastic polyamideimide, thermoplastic polyetherimide, thermoplastic polyesterimide, and the like can be suitably used. The thermoplastic polyimide in the present invention has a glass transition temperature and is 10 to 400 ° C. (temperature increase rate: 10) in thermomechanical analysis (TMA) in compression mode (probe diameter 3 mmφ, load 5 g). That which causes permanent compression deformation in the temperature range of ° C / min).

  Further, from the viewpoint of heat resistance, the adhesive layer preferably has a higher glass transition temperature (Tg), and it is preferable to use an adhesive layer that can be bonded to the metal foil at 300 ° C. or higher. The state “possible to be bonded to a metal foil” as used herein refers to a state in which the storage elastic modulus of the adhesive layer is greatly lowered by heat and expresses meltability. Specifically, the storage elastic modulus of the adhesive layer at 300 ° C. or higher is preferably 10 GPa or less, and more preferably 1 GPa or less. Especially preferably, it is 0.1 GPa or less.

  However, if the Tg of the adhesive layer is excessively increased, the laminating temperature becomes very high, so that it may be impossible to perform lamination with an existing apparatus. The thermoplastic polyimide in the present invention has a Tg in the range of 150 to 300 ° C., considering that it can be laminated with existing equipment and does not impair the heat resistance of the resulting metal-clad laminate. It is preferable. 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 is not particularly limited, and any known polyamic acid can be used. Also for the production, known raw materials, reaction conditions, and the like can be used (for example, see Examples described later). Moreover, you may add an inorganic or organic filler as needed.

  The adhesive film used for manufacturing the flexible metal-clad laminate according to the present invention can be obtained by providing an adhesive layer on at least one surface of the insulating film. As a method for producing the adhesive film, a method of forming an adhesive layer on the insulating film to be the core film, a method of forming the adhesive layer into a sheet shape, and bonding the resultant to the core film can be suitably exemplified.

  Among these, when the former method is adopted, the method of casting and applying the adhesive solution to the core film is not particularly limited, and existing methods such as a die coater, a reverse coater, and a blade coater can be used. However, when thermoplastic polyimide is contained in the adhesive layer, if the polyamic acid that is the precursor of the thermoplastic polyimide is completely imidized, the solubility in an organic solvent may decrease, so the core film It may be difficult to provide the adhesive layer thereon. Therefore, from the above viewpoint, it is more preferable to prepare a solution containing polyamic acid which is a precursor of thermoplastic polyimide, apply this to the core film, and then imidize. As the imidization method at this time, either a thermal cure method or a chemical cure method can be used.

  Regardless of which imidation procedure is employed, heating is performed in order to promote imidization efficiently, and the temperature at that time ranges from (glass transition temperature of thermoplastic polyimide−100 ° C.) to (glass transition temperature + 200 ° C.). It is preferable to set within the range of (Glass transition temperature of thermoplastic polyimide−50 ° C.) to (Glass transition temperature + 150 ° C.). The higher the temperature of the heat curing, the easier the imidization occurs, so the curing speed can be increased, which is preferable in terms of productivity. However, if it is too high, the thermoplastic polyimide may cause thermal decomposition. On the other hand, if the temperature of the heat curing is too low, imidization is difficult to proceed even with chemical curing, and the time required for the curing process becomes long.

  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. Moreover, in order to improve the melt fluidity of the adhesive layer, it is possible to intentionally lower the imidization rate and / or leave the solvent.

  The tension applied during imidization is preferably in the range of 1 kg / m to 15 kg / m, and particularly preferably in the range of 5 kg / m to 10 kg / m. If the tension is smaller than the above range, sagging or meandering may occur during film conveyance, which may cause problems such as wrinkling during winding or inability to uniformly wind. On the other hand, when it is larger than the above range, since it is heated at a high temperature in a state where a strong tension is applied, the dimensional characteristics of the obtained flexible metal-clad laminate may be deteriorated.

  In addition, the adhesive layer may include other materials such as a filler, depending on the application. In addition, if necessary, various surface treatments such as corona treatment, plasma treatment, and coupling treatment may be performed on the surface of the core film before providing the adhesive layer. What is necessary is just to adjust suitably about the thickness structure of each layer (core insulating film layer, adhesive layer) of an adhesive film so that it may become the total thickness according to a use.

  The metal foil used in the present invention is not particularly limited, but when the flexible metal-clad laminate of the present invention is used for electronic equipment / electric equipment, for example, copper or copper alloy, stainless steel or its Examples include foils made of alloys, nickel, nickel alloys (including 42 alloys), aluminum, or aluminum alloys. In general flexible metal-clad laminates, copper foil such as rolled copper foil and electrolytic copper foil is frequently used, but it can also be preferably used in the present invention. In addition, the antirust layer, the heat-resistant layer, or the contact bonding layer may be apply | coated to the surface of these metal foil.

  In the present invention, the thickness of the metal foil is not particularly limited, and may be any thickness that can exhibit a sufficient function depending on the application. It is preferably -35 µm, more preferably 2-25 µm, particularly 3-18 µm. If the thickness of the metal foil is less than this range, connection failure or connection reliability is liable to decrease when mounted on various substrates using an anisotropic conductive film, etc., and if it exceeds the above range, fine wiring is formed. Tend to be difficult. The metal foil can be laminated using a thicker one, and then thinned by a known method such as etching.

  In order to bond the metal foil and the polyimide film through the adhesive layer in the present invention, for example, a hot roll laminating apparatus having a pair of metal rolls or a continuous treatment by a double belt press (DBP) can be used. Among these, it is preferable to use a hot roll laminating apparatus having a pair of metal rolls because the apparatus configuration is simple and advantageous in terms of maintenance cost. The “heat roll laminating apparatus having a pair of metal rolls” herein may be an apparatus having a metal roll for heating and pressurizing a material, and the specific apparatus configuration is particularly limited. It is not a thing.

  The specific configuration of the means for carrying out the thermal lamination is not particularly limited, but a protective material is disposed between the pressing surface and the metal foil in order to improve the appearance of the resulting laminate. It is preferable to do. The protective material is not particularly limited as long as it can withstand the heating temperature in the heat laminating process, and preferably a heat-resistant plastic such as a non-thermoplastic polyimide film, a metal foil such as a copper foil, an aluminum foil, or a SUS foil. Can be used. Among these, a polyimide film, particularly a non-thermoplastic polyimide film, is more preferably used from the viewpoint of excellent balance between heat resistance and reuse. In addition, if the thickness is thin, the function of buffering and protecting at the time of lamination will not be sufficiently fulfilled, so the thickness of the non-thermoplastic polyimide film is preferably 75 μm or more.

  Further, the protective material does not necessarily have to be a single layer, and may have a multilayer structure of two or more layers having different characteristics.

  Further, when the laminate temperature is high, if the protective material is used as it is for the laminate, the appearance and dimensional stability of the obtained flexible metal-clad laminate may be deteriorated due to rapid thermal expansion. Therefore, it is preferable to preheat the protective material before lamination. Examples of the preheating means include a method of bringing a protective material into contact with a heating roll. The contact time is preferably 1 second or longer, more preferably 10 seconds or longer. By preheating the protective material, since the thermal expansion of the protective material is completed when laminating, the appearance and dimensional characteristics of the flexible metal-clad laminate are suppressed. When the contact time is shorter than the above, since the lamination is performed without the thermal expansion of the protective material, the thermal expansion of the protective material occurs during the lamination, and the appearance and dimensional characteristics of the resulting flexible metal-clad laminate are deteriorated. There are things to do. The distance at which the protective material is held on the heating roll is not particularly limited, and may be appropriately adjusted from the diameter of the heating roll and the contact time.

  When thermoplastic polyimide is contained in the adhesive layer of the adhesive film, the laminating temperature is inevitably high, so that the difference between the temperature of the flexible metal-clad laminate immediately after laminating and room temperature becomes large. Therefore, if the protective material is peeled off immediately after lamination, the flexible metal-clad laminate is rapidly cooled without being held by the protective material, causing rapid contraction, and the appearance and dimensional characteristics may be deteriorated. Therefore, after lamination, it is preferable to cool the flexible metal-clad laminate with the protective material adhered and fixed, and to peel off the protective material when the temperature of the flexible metal-clad laminate is lowered to some extent. The timing at which the protective material is peeled off from the flexible metal-clad laminate is preferably when the temperature of the flexible metal-clad laminate is equal to or lower than the glass transition temperature of the adhesive layer + 50 ° C., and is lower than the glass transition temperature of the adhesive layer + 20 ° C. Time points are more preferred. If the protective material is peeled before the temperature is lowered, the appearance and dimensional characteristics may be deteriorated.

  The heating method of the material to be laminated in the heat laminating means is not particularly limited. For example, heating using a conventionally known method capable of heating at a predetermined temperature, such as a heat circulation method, a hot air heating method, an induction heating method, or the like. Means can be used. Similarly, the pressurization method of the material to be laminated in the heat laminating means is not particularly limited, and a conventionally known method capable of applying a predetermined pressure such as a hydraulic method, a pneumatic method, a gap pressure method, etc. The pressurizing means adopting can be used.

  The heating temperature in the heat laminating step, that is, the laminating temperature is preferably a temperature of Tg + 50 ° C. or higher of the adhesive film, and more preferably Tg + 100 ° C. of the adhesive film. If it is Tg + 50 degreeC or more temperature, an adhesive film and metal foil can be heat-laminated favorably. Moreover, if it is Tg + 100 degreeC or more, the lamination speed | rate can be raised and the productivity can be improved more.

  The laminating speed in the thermal laminating step is preferably 0.5 m / min or more, and more preferably 1.0 m / min or more. If it is 0.5 m / min or more, sufficient thermal lamination is possible, and if it is 1.0 m / min or more, productivity can be further improved.

  The higher the pressure in the thermal laminating process, that is, the laminating pressure, there is an advantage that the laminating temperature can be lowered and the laminating speed can be increased, but generally the flexible metal-clad laminate obtained when the laminating pressure is too high. Dimensional characteristics tend to deteriorate. Conversely, if the laminating pressure is too low, the adhesive strength of the metal foil of the flexible metal-clad laminate obtained is lowered. Therefore, the laminating pressure is preferably in the range of 49 to 490 N / cm (5 to 50 kgf / cm), and more preferably in the range of 98 to 294 N / cm (10 to 30 kgf / cm). Within this range, the three conditions of the lamination temperature, the lamination speed and the lamination pressure can be made favorable, and the productivity can be further improved.

  The polyimide film tension during lamination is preferably 0.01 to 2 N / cm, more preferably 0.02 to 1.5 N / cm, and particularly preferably 0.05 to 1.0 N / cm. If the tension is below this range, it may be difficult to obtain a flexible metal-clad laminate with good appearance, and if it exceeds this range, the dimensional stability tends to be inferior.

  When thermoplastic polyimide is contained in the adhesive layer of the adhesive film, the laminating temperature is inevitably high, so the flexible metal-clad laminate immediately after laminating is also very hot. Therefore, the flexible metal-clad laminate immediately after lamination tends to generate thermal stress due to tension. Therefore, the flexible metal-clad laminate immediately after lamination is brought into contact with a heating roll while the protective material is still placed, etc., and is gradually cooled to a certain extent in a state where it is not affected by tension, and at the same time heat laminated It is preferable to relieve the residual strain that is sometimes generated and then separate it from the heating roll. The contact time with the heating roll is preferably 0.1 seconds or more, more preferably 0.2 seconds or more, and particularly preferably 0.5 seconds or more. When the contact time is shorter than the above range, the temperature of the flexible metal-clad laminate is hardly lowered, and the dimensional characteristics may deteriorate due to the influence of tension. The holding time is preferably as long as possible. However, since it depends on the roll diameter and the laminating speed, it is adjusted within a range that can be selected by those skilled in the art in consideration of productivity and equipment specifications.

  In addition, even if it is gradually cooled by bringing it into contact with a heating roll after lamination, the difference between the flexible metal-clad laminate and the room temperature is still large, and the residual strain may not be alleviated. Problems may arise in the appearance or dimensional characteristics of the laminate. Therefore, the flexible metal-clad laminate after being brought into contact with a heating roll and gradually cooled is preferably passed through a post-heating step with the protective material still disposed. The tension at this time is preferably in the range of 1 to 10 N / cm. Moreover, it is preferable to make the atmospheric temperature of post-heating into the range of (lamination temperature -200 degreeC)-(lamination temperature +100 degreeC). The “atmosphere temperature” here refers to the outer surface temperature of the protective material in close contact with both surfaces of the flexible metal-clad laminate. The actual temperature of the flexible metal-clad laminate varies somewhat depending on the thickness of the protective material, but if the temperature of the surface of the protective material is within the above range, the effect of post-heating can be exhibited. The outer surface temperature of the protective material can be measured using a thermocouple or a thermometer.

  When the tension is smaller than the above range, sagging or the like occurs during conveyance, and it may be difficult to obtain a flexible metal-clad laminate having a good appearance. Conversely, when it is larger than the above range, since a strong tension is applied while being heated, the dimensional stability of the obtained flexible metal-clad laminate may be deteriorated. On the other hand, when the post-heating temperature is out of the above range, the effect of post-heating may not be sufficiently exhibited, and the appearance or dimensional characteristics of the flexible metal-clad laminate may not be improved or deteriorated.

  The heating method in the post-heating step is not particularly limited, and examples thereof include a heater method capable of controlling the temperature in the width direction, a heating roll method, and a heating oven method. The heater is not particularly limited as long as it can be adjusted to a predetermined temperature, and can be a far red heater or a near red heater. The set temperature in each heating method is appropriately adjusted depending on the distance between the heat source and the laminate, the installation interval, and the like, but the ambient temperature in the post-heating step is within the above range.

  In order to obtain the flexible metal-clad laminate according to the present invention, it is preferable to use a thermal laminating apparatus that continuously press-bonds the material to be laminated while heating, but in this thermal laminating apparatus, before the thermal laminating means, A laminated material feeding means for feeding the laminated material may be provided, or a laminated material winding means for winding the laminated material may be provided after the thermal laminating means. By providing these means, the productivity of the thermal laminating apparatus can be further improved. The specific configuration of the laminated material feeding means and the laminated material winding means is not particularly limited. For example, a known roll shape capable of winding an adhesive film, a metal foil, or a laminated sheet to be obtained. A winder etc. can be mentioned.

  Furthermore, it is more preferable to provide a protective material winding means and a protective material feeding means for winding and feeding the protective material. If these protective material take-up means and protective material feeding means are provided, the protective material can be reused by winding the protective material once used in the thermal laminating step and installing it again on the pay-out side. . Further, when winding the protective material, end position detecting means and winding position correcting means may be provided in order to align both ends of the protective material. As a result, the end portions of the protective material can be aligned and wound with high accuracy, so that the efficiency of reuse can be increased. The specific configurations of the protective material winding means, the protective material feeding means, the end position detecting means, and the winding position correcting means are not particularly limited, and various conventionally known devices can be used.

  In the flexible metal-clad laminate obtained by the manufacturing method according to the present invention, the dimensional change rate before and after removing the metal foil, and the total value of the dimensional change rate before and after heating at 250 ° C. for 30 minutes after removing the metal foil. Is very preferably in the range of −0.05 to +0.05 in both the MD direction and the TD direction. Further, when the standard deviation of the dimensional change rate before and after removing the metal foil and the total value of the dimensional change rate before and after performing heat treatment at 250 ° C. for 30 minutes after removing the metal foil is σ, MD direction, TD direction In both cases, it is very preferable that 3σ is 0.02 or less. The rate of dimensional change before and after removal of the metal foil is expressed as a ratio between a difference between a predetermined dimension in the flexible metal-clad laminate before the etching process and a predetermined dimension after the etching process and a predetermined dimension before the etching process. . The dimensional change rate before and after heating is represented by a ratio between a difference between a predetermined dimension in the flexible metal-clad laminate after the etching process and a predetermined dimension after the heating process and a predetermined dimension before the heating process.

  If the dimensional change rate is out of the above range, the flexible metal-clad laminate tends to have a high defect rate during component mounting. Further, when 3σ of the dimensional change rate is out of the above range, the variation for each product lot increases, and similarly, the defect rate at the time of component mounting tends to increase.

  The method for measuring the dimensional change rate is not particularly limited, and any method known in the art can be used as long as it can measure the increase or decrease in dimensions that occurs before and after the etching or heating process in the flexible metal-clad laminate. Can be used.

  Here, it is essential to measure the dimensional change rate in both the MD direction and the TD direction. When imidizing and laminating continuously, the tension is different in the MD direction and the TD direction, so a difference appears in the degree of thermal expansion / contraction and the dimensional change rate is also different. Therefore, a material having a small dimensional change rate is required to have a low change rate in both the MD direction and the TD direction. In the present invention, the dimensional change rate before and after removing the metal foil of the flexible metal-clad laminate, and the total value of the dimensional change rate before and after heating at 250 ° C. for 30 minutes after removing the metal foil are MD direction, It is very preferable that the TD direction is in the range of -0.05 to +0.05. Furthermore, it is very preferable that 3σ is 0.02 or less in both the MD direction and the TD direction.

  In addition, the specific conditions of the etching process at the time of measuring a dimensional change rate are not specifically limited. That is, since the etching conditions differ depending on the type of metal foil and the shape of the pattern wiring to be formed, the etching process conditions for measuring the dimensional change rate in the present invention are any conventionally known conditions. Also good. Similarly, in the heating process, it is sufficient that heating is performed at 250 ° C. for 30 minutes, and specific conditions are not particularly limited.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to these Examples.

  In addition, the tensile elastic modulus, linear expansion coefficient, storage elastic modulus and storage elastic modulus lowering start point of thermoplastic film, glass transition temperature of thermoplastic polyimide, dimensional change rate of flexible laminate, metal in synthesis examples, examples and comparative examples The evaluation method of the foil peel strength is as follows.

(Tensile modulus)
The measurement of the tensile elastic modulus was performed according to ASTM D882.

(Linear expansion coefficient)
The linear expansion coefficient at 50 to 200 ° C. was measured by using TMA120C manufactured by Seiko Electronics Co., Ltd. (sample size: 3 mm width, 10 mm length), and the temperature was temporarily increased from 10 ° C. to 400 ° C. at a load of 3 g at 10 ° C./min. After heating, it was cooled to 10 ° C., further heated at 10 ° C./min, and calculated as an average value from the thermal expansion coefficients at 50 ° C. and 200 ° C. during the second temperature increase.

(Storage elastic modulus measurement)
Using a DMS200 manufactured by Seiko Electronics Co., Ltd. (sample size: width 9 mm, length 40 mm), measured at a frequency of 1, 5 and 10 Hz at a temperature rising rate of 3 ° C./min in a temperature range of 20 to 400 ° C., and storage elasticity The starting point of rate decrease and the storage elastic modulus at 380 ° C. were evaluated. The temperature at the inflection point was set as the onset of storage elastic modulus decrease.

(Judgment of thermoplasticity)
Using TMA120C manufactured by Seiko Electronics Co., Ltd., compression mode (probe diameter: 3 mmφ), 10 ° C / min at a load of 5 g, the temperature was once raised from 10 ° C to 400 ° C, cooled to 10 ° C, and subjected to permanent compression deformation The presence or absence was judged.

(Glass-transition temperature)
The glass transition temperature of the thermoplastic polyimide was measured in a temperature range from room temperature to 400 ° C. at a rate of temperature increase of 3 ° C./min using a DMS200 manufactured by Seiko Electronics Co., Ltd. The transition temperature was used.

(Dimensional change rate)
Based on JIS C6481, four holes were formed in the flexible laminate, and the distance of each hole was measured. Next, after carrying out an etching process to remove the metal foil from the flexible laminate, it was left in a temperature-controlled room at 20 ° C. and 60% RH for 24 hours. Then, each distance was measured about the said four holes similarly to the etching process front. The measured value of the distance of each hole before metal foil removal was set to D1, and the measured value of the distance of each hole after metal foil removal was set to D2, and the dimensional change rate was calculated | required by following Formula.
Dimensional change rate (%) = {(D2-D1) / D1} × 100
In addition, the said dimensional change rate was measured about both MD direction and TD direction.

Subsequently, the measurement sample after etching was heated at 250 ° C. for 30 minutes and then left in a constant temperature room at 20 ° C. and 60% RH for 24 hours. Then, each distance was measured about the said four holes. The measured value of the distance of each hole after heating was set to D3, and the dimensional change rate before and after heating was obtained by the following formula.
Dimensional change rate (%) = {(D3-D2) / D2} × 100
In addition, the said dimensional change rate was measured about both MD direction and TD direction.

(Stripping strength of metal foil: Adhesive strength)
A sample was prepared according to “6.5 Peel Strength” of JIS C6471, and a 5 mm wide metal foil part was peeled off at a peeling angle of 180 degrees and 50 mm / min, and the load was measured.

(Synthesis Example 1)
780 g of DMF and 115.6 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) were added to a glass flask having a capacity of 2000 ml, and 3,3′4 while stirring under a nitrogen atmosphere. , 4′-Biphenyltetracarboxylic dianhydride (BPDA) was gradually added. Subsequently, 3.8 g of ethylenebis (trimellitic acid monoester acid anhydride) (TMEG) was added and stirred for 30 minutes in an ice bath. A solution in which 2.0 g of TMEG was dissolved in 20 g of DMF was separately prepared, and this was gradually added to the reaction solution while being careful of the viscosity and stirred. When the viscosity reached 3000 poise, addition and stirring were stopped to obtain a polyamic acid solution.

  This polyamic acid solution was cast on a 25 μm PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) so as to have a final thickness of 20 μm, and dried at 120 ° C. for 5 minutes. After peeling off the dried self-supporting film from PET, it is fixed to a metal pin frame and dried at 150 ° C. for 5 minutes, 200 ° C. for 5 minutes, 250 ° C. for 5 minutes, 350 ° C. for 5 minutes, A single layer sheet was obtained. The glass transition temperature of this thermoplastic polyimide was 240 ° C. Further, in the determination of thermoplasticity, it was found that the thermoplastic has thermoplasticity due to the occurrence of permanent compression deformation.

Example 1
After dissolving 6.20 kg of p-phenylenediamine (p-PDA) and 11.50 kg of 4,4′-oxydianiline (ODA) in 229 kg of N, N-dimethylformamide (DMF) cooled to 10 ° C., benzophenone tetra 18.50 kg of carboxylic acid dianhydride (BTDA) was added and dissolved, and 15.79 kg of p-phenylenebis (trimellitic acid monoester acid anhydride) (TMHQ) was further dissolved. To this, 4.01 kg of pyromellitic dianhydride (PMDA) was further added and stirred for 1 hour to completely dissolve it. A separately prepared DMF solution of PMDA (PMDA: DMF = 1.0 kg: 14 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of 19% by weight and a rotational viscosity at 23 ° C. of 3400 poise.

In this polyamic acid solution, a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was continuously stirred with a mixer at a weight ratio of 50% with respect to the polyamic acid solution. It was extruded from a T die and cast onto a stainless endless belt running 20 mm below the die. The resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt (volatile content 45% by weight) and fixed to the tenter clip, 300 ° C. for 20 seconds, 450 ° C. × 20 After being dried and imidized at 500 ° C. for 20 seconds, plasma treatment was performed to obtain a 17 μm polyimide film.
Storage elastic modulus decrease start temperature: 265 ° C
Storage elastic modulus at 380 ° C .: 0.3 GPa
Tensile modulus: 6 GPa
Linear expansion coefficient: 17ppm
After diluting the polyamic acid solution obtained in Synthesis Example 1 with DMF until the solid content concentration becomes 10% by weight, the final single-sided thickness of the thermoplastic polyimide layer (adhesive layer) is 4 μm on both sides of the 17 μm polyimide film. After applying the polyamic acid, heating was performed at 140 ° C. for 1 minute. Then, it passed through the far-infrared heater furnace with an atmospheric temperature of 390 ° C. for 20 seconds to carry out heating imidization to obtain an adhesive film. The linear expansion coefficient was 23 ppm. Polyimide using 18 μm rolled copper foil (BHY-22B-T, manufactured by Japan Energy) on both sides of the obtained adhesive film and apical 125 NPI (manufactured by Kaneka Chemical Co., Ltd.) on both sides of the copper foil as protective materials. Thermally laminating under the conditions of film tension 0.4N / cm, laminating temperature 380 ° C, laminating pressure 196N / cm (20kgf / cm), laminating speed 1.5m / min, flexible copper clad laminate (FCCL ) Was produced. Table 1 shows the characteristics of this FCCL.

(Example 2)
After dissolving 1.55 kg of 4,4′-oxydianiline (ODA) and 4.50 kg of p-phenylenediamine (p-PDA) in 229 kg of N, N-dimethylformamide (DMF) cooled to 10 ° C., benzophenone tetra 7.67 kg of carboxylic dianhydride (BTDA) was added and dissolved, and further 16.36 kg of p-phenylenebis (trimellitic acid monoester anhydride) (TMHQ) was dissolved. To this, 11.94 kg of pyromellitic dianhydride (PMDA) was further added and stirred for 1 hour to completely dissolve it. A separately prepared DMF solution of PMDA (PMDA: DMF = 1.04 kg: 14 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of 19% by weight and a rotational viscosity at 23 ° C. of 3200 poise.

In this polyamic acid solution, a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was continuously stirred with a mixer at a weight ratio of 50% with respect to the polyamic acid solution. It was extruded from a T die and cast onto a stainless endless belt running 20 mm below the die. The resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt (volatile content 45% by weight) and fixed to the tenter clip, 300 ° C. for 20 seconds, 450 ° C. × 20 After being dried and imidized at 500 ° C. for 20 seconds, plasma treatment was performed to obtain a 17 μm polyimide film.
Storage elastic modulus decrease start temperature: 277 ° C
Storage elastic modulus at 380 ° C .: 0.5 GPa
Tensile modulus: 5.3 GPa
Linear expansion coefficient: 17ppm
After diluting the polyamic acid solution obtained in Synthesis Example 1 with DMF until the solid content concentration becomes 10% by weight, the final single-sided thickness of the thermoplastic polyimide layer (adhesive layer) is 4 μm on both sides of the 17 μm polyimide film. After applying the polyamic acid, heating was performed at 140 ° C. for 1 minute. Then, it passed through the far-infrared heater furnace with an atmospheric temperature of 390 ° C. for 20 seconds to carry out heating imidization to obtain an adhesive film. The linear expansion coefficient was 23 ppm. Polyimide using 18 μm rolled copper foil (BHY-22B-T, manufactured by Japan Energy) on both sides of the obtained adhesive film and apical 125 NPI (manufactured by Kaneka Chemical Co., Ltd.) on both sides of the copper foil as protective materials. FCCL was produced by continuous thermal lamination under the conditions of film tension of 0.4 N / cm, laminating temperature of 380 ° C., laminating pressure of 196 N / cm (20 kgf / cm), laminating speed of 1.5 m / min. Table 1 shows the characteristics of this FCCL.

( Reference Example 3; Production of polyimide film)
After dissolving 4.08 kg of p-phenylenediamine (p-PDA) in 234 kg of N, N-dimethylformamide (DMF) cooled to 10 ° C., 4.12 kg of pyromellitic dianhydride (PMDA) was added for 1 hour. Stir to dissolve completely. Further, 15.50 kg of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) was dissolved, and then p-phenylenebis (trimellitic acid monoester anhydride) (TMHQ) 10.38 kg. Was dissolved. Further, 6.76 kg of pyromellitic dianhydride (PMDA) was added thereto and stirred for 1 hour to completely dissolve. A separately prepared DMF solution of PMDA (PMDA: DMF = 0.65 kg: 9 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of 19% by weight and a rotational viscosity at 23 ° C. of 3200 poise.

In this polyamic acid solution, a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was continuously stirred with a mixer at a weight ratio of 50% with respect to the polyamic acid solution. It was extruded from a T die and cast onto a stainless endless belt running 20 mm below the die. The resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt (volatile content 45% by weight) and fixed to the tenter clip, 300 ° C. for 20 seconds, 450 ° C. × 20 After being dried and imidized at 500 ° C. for 20 seconds, plasma treatment was performed to obtain a 17 μm polyimide film.
Storage elastic modulus decrease start temperature: 285 ° C
Storage elastic modulus at 380 ° C .: 0.7 GPa
Tensile modulus: 4.5 GPa
Linear expansion coefficient: 19ppm
After diluting the polyamic acid solution obtained in Synthesis Example 1 with DMF until the solid content concentration becomes 10% by weight, the final single-sided thickness of the thermoplastic polyimide layer (adhesive layer) is 3 μm on both sides of the 17 μm polyimide film. After applying the polyamic acid, heating was performed at 140 ° C. for 1 minute. Then, it passed through the far-infrared heater furnace with an atmospheric temperature of 390 ° C. for 20 seconds to carry out heating imidization to obtain an adhesive film. The linear expansion coefficient was 24 ppm. Polyimide using 18 μm rolled copper foil (BHY-22B-T, manufactured by Japan Energy) on both sides of the obtained adhesive film and apical 125 NPI (manufactured by Kaneka Chemical Co., Ltd.) on both sides of the copper foil as protective materials. FCCL was produced by continuous thermal lamination under the conditions of film tension of 0.4 N / cm, laminating temperature of 380 ° C., laminating pressure of 196 N / cm (20 kgf / cm), laminating speed of 1.5 m / min. Table 1 shows the characteristics of this FCCL.

Example 4
After dissolving 3.09 kg of p-phenylenediamine (p-PDA) in 233 kg of N, N-dimethylformamide (DMF) cooled to 10 ° C., 5.98 kg of pyromellitic dianhydride (PMDA) was added for 1 hour. Stir to dissolve completely. Further, after 17.17 kg of 4,4′-oxydianiline (ODA) was dissolved, 15.72 kg of p-phenylenebis (trimellitic acid monoester anhydride) (TMHQ) was dissolved. Here, 11.05 kg of BTDA was added and dissolved, and 3.19 kg of pyromellitic dianhydride (PMDA) was further added and stirred for 1 hour to completely dissolve. A separately prepared DMF solution of PMDA (PMDA: DMF = 0.80 kg: 10 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of 19% by weight and a rotational viscosity at 23 ° C. of 3500 poise.

In this polyamic acid solution, a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was continuously stirred with a mixer at a weight ratio of 50% with respect to the polyamic acid solution. It was extruded from a T die and cast onto a stainless endless belt running 20 mm below the die. The resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt (volatile content 45% by weight) and fixed to the tenter clip, 300 ° C. for 20 seconds, 450 ° C. × 20 After being dried and imidized at 500 ° C. for 20 seconds, plasma treatment was performed to obtain a 17 μm polyimide film.
Storage elastic modulus decrease start temperature: 252 ° C
Storage elastic modulus at 380 ° C .: 0.2 GPa
Tensile modulus: 6.5 GPa
Linear expansion coefficient: 12ppm
After diluting the polyamic acid solution obtained in Synthesis Example 1 with DMF to a solid content concentration of 10% by weight, the final single-sided thickness of the thermoplastic polyimide layer (adhesive layer) is 4. on both sides of the 17 μm polyimide film. After applying polyamic acid so as to be 5 μm, heating was performed at 140 ° C. for 1 minute. Then, it passed through the far-infrared heater furnace with an atmospheric temperature of 390 ° C. for 20 seconds to carry out heating imidization to obtain an adhesive film. The linear expansion coefficient was 22 ppm. Polyimide using 18 μm rolled copper foil (BHY-22B-T, manufactured by Japan Energy) on both sides of the obtained adhesive film and apical 125 NPI (manufactured by Kaneka Chemical Co., Ltd.) on both sides of the copper foil as protective materials. FCCL was produced by continuous thermal lamination under the conditions of film tension of 0.4 N / cm, laminating temperature of 380 ° C., laminating pressure of 196 N / cm (20 kgf / cm), laminating speed of 1.5 m / min. Table 1 shows the characteristics of this FCCL.

(Comparative Example 1)
After dissolving 5.96 kg of p-PDA in 235 kg of N, N-dimethylformamide (DMF) cooled to 10 ° C., 15.15 kg of p-phenylenebis (trimellitic acid monoester anhydride) (TMHQ) is dissolved. I let you. Further, 6.75 kg of benzophenonetetracarboxylic dianhydride (BTDA) was added and completely dissolved. Further, after 8.82 kg of 4,4′-oxydianiline (ODA) was added and dissolved, 4.52 kg of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) was further dissolved. Here, 11.00 kg of BTDA was dissolved, and further 4.79 kg of PMDA was added and stirred for 1 hour to completely dissolve. A separately prepared DMF solution of PMDA (PMDA: DMF = 0.72 kg: 9 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of 19% by weight and a rotational viscosity at 23 ° C. of 3200 poise.

In this polyamic acid solution, a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was continuously stirred with a mixer at a weight ratio of 50% with respect to the polyamic acid solution. It was extruded from a T die and cast onto a stainless endless belt running 20 mm below the die. The resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt (volatile content 45% by weight) and fixed to the tenter clip, 300 ° C. for 20 seconds, 450 ° C. × 20 After being dried and imidized at 500 ° C. for 20 seconds, plasma treatment was performed to obtain a 17 μm polyimide film.
Storage elastic modulus decrease start temperature: 233 ° C
Storage elastic modulus at 380 ° C .: 0.2 GPa
Tensile modulus: 5.6 GPa
Linear expansion coefficient: 20ppm
After diluting the polyamic acid solution obtained in Synthesis Example 1 with DMF until the solid content concentration becomes 10% by weight, the final thickness of one side of the thermoplastic polyimide layer (adhesive layer) on both sides of the 17 μm polyimide film is 2. After applying polyamic acid so as to be 5 μm, heating was performed at 140 ° C. for 1 minute. Then, it passed through the far-infrared heater furnace with an atmospheric temperature of 390 ° C. for 20 seconds to carry out heating imidization to obtain an adhesive film. The linear expansion coefficient was 23 ppm. Polyimide using 18 μm rolled copper foil (BHY-22B-T, manufactured by Japan Energy) on both sides of the obtained adhesive film and apical 125 NPI (manufactured by Kaneka Chemical Co., Ltd.) on both sides of the copper foil as protective materials. FCCL was produced by continuous thermal lamination under the conditions of film tension of 0.4 N / cm, laminating temperature of 380 ° C., laminating pressure of 196 N / cm (20 kgf / cm), laminating speed of 1.5 m / min. Table 1 shows the characteristics of this FCCL.

(Comparative Example 2)
To 234 kg of N, N-dimethylformamide (DMF) cooled to 10 ° C., 7.23 kg of p-PDA was added and dissolved, and 13.37 kg of PMDA was added and completely dissolved. Further, 1.83 kg of BAPP was dissolved, and 7.66 kg of TMHQ was added and completely dissolved. Further, 9.70 kg of BTDA was added thereto and stirred for 1 hour to completely dissolve. A separately prepared DMF solution of PMDA (PMDA: DMF = 0.73 kg: 9 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of 19% by weight and a rotational viscosity at 23 ° C. of 3300 poise.

In this polyamic acid solution, a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was continuously stirred with a mixer at a weight ratio of 50% with respect to the polyamic acid solution. It was extruded from a T die and cast onto a stainless endless belt running 20 mm below the die. The resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt (volatile content 45% by weight) and fixed to the tenter clip, 300 ° C. for 20 seconds, 450 ° C. × 20 After being dried and imidized at 500 ° C. for 20 seconds, plasma treatment was performed to obtain a 17 μm polyimide film.
Storage elastic modulus decrease start temperature: 265 ° C
Storage elastic modulus at 380 ° C .: 2 GPa
Tensile modulus: 7 GPa
Linear expansion coefficient: 7ppm
After diluting the polyamic acid solution obtained in Synthesis Example 1 with DMF to a solid content concentration of 10% by weight, the final thickness of one side of the thermoplastic polyimide layer (adhesive layer) is 5 μm on both sides of the 17 μm polyimide film. After applying the polyamic acid, heating was performed at 140 ° C. for 1 minute. Then, it passed through the far-infrared heater furnace with an atmospheric temperature of 390 ° C. for 20 seconds to carry out heating imidization to obtain an adhesive film. The linear expansion coefficient was 21 ppm. Polyimide using 18 μm rolled copper foil (BHY-22B-T, manufactured by Japan Energy) on both sides of the obtained adhesive film and apical 125 NPI (manufactured by Kaneka Chemical Co., Ltd.) on both sides of the copper foil as protective materials. FCCL was produced by continuous thermal lamination under the conditions of film tension of 0.4 N / cm, laminating temperature of 380 ° C., laminating pressure of 196 N / cm (20 kgf / cm), laminating speed of 1.5 m / min. Table 1 shows the characteristics of this FCCL.

(Comparative Example 3)
After dissolving 13.4 kg of 4,4′-oxydianiline (ODA) and 7.21 kg of p-phenylenediamine (p-PDA) in 232 kg of N, N-dimethylformamide (DMF) cooled to 10 ° C., benzophenone tetra Carboxylic dianhydride (BTDA) was added and dissolved in 12.89 kg, and p-phenylenebis (trimellitic acid monoester acid anhydride) (TMHQ) in 6.11 kg was dissolved. Further, 16.58 kg of pyromellitic dianhydride (PMDA) was added thereto and stirred for 1 hour to completely dissolve. A separately prepared DMF solution of PMDA (PMDA: DMF = 0.87 kg: 11 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of 19% by weight and a rotational viscosity at 23 ° C. of 3400 poise.

In this polyamic acid solution, a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was continuously stirred with a mixer at a weight ratio of 50% with respect to the polyamic acid solution. It was extruded from a T die and cast onto a stainless endless belt running 20 mm below the die. The resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt (volatile content 45% by weight) and fixed to the tenter clip, 300 ° C. for 20 seconds, 450 ° C. × 20 After being dried and imidized at 500 ° C. for 20 seconds, plasma treatment was performed to obtain a 17 μm polyimide film.
Storage elastic modulus decrease start temperature: 312 ° C
Storage elastic modulus at 380 ° C .: 1.5 GPa
Tensile modulus: 6.1 GPa
Linear expansion coefficient: 15ppm
After diluting the polyamic acid solution obtained in Synthesis Example 1 with DMF until the solid content concentration becomes 10% by weight, the final single-sided thickness of the thermoplastic polyimide layer (adhesive layer) is 4 μm on both sides of the 17 μm polyimide film. After applying the polyamic acid, heating was performed at 140 ° C. for 1 minute. Then, it passed through the far-infrared heater furnace with an atmospheric temperature of 390 ° C. for 20 seconds to carry out heating imidization to obtain an adhesive film. The linear expansion coefficient was 23 ppm. Polyimide using 18 μm rolled copper foil (BHY-22B-T, manufactured by Japan Energy) on both sides of the obtained adhesive film and apical 125 NPI (manufactured by Kaneka Chemical Co., Ltd.) on both sides of the copper foil as protective materials. FCCL was produced by continuous thermal lamination under the conditions of film tension of 0.4 N / cm, laminating temperature of 380 ° C., laminating pressure of 196 N / cm (20 kgf / cm), laminating speed of 1.5 m / min. Table 1 shows the characteristics of this FCCL.

  As shown in Comparative Examples 1 to 3, when the properties of the core film were out of the specified range, the thermal laminate method resulted in large dimensional changes and variations in the flexible metal-clad laminate.

  On the other hand, in Examples 1 to 4 in which all the characteristics are within the predetermined range, the occurrence of the dimensional change and the variation in the dimensional change were suppressed, and the adhesiveness was not deteriorated.

Claims (9)

An adhesive film for a flexible metal-clad laminate in which an adhesive layer is provided on at least one surface of the insulating film, the insulating film having a storage elastic modulus lowering start temperature of 250 ° C. or higher, and an insulating property at a metal foil bonding temperature storage modulus of the film is Ri 0.01G~1.0GPa der,
The insulating film includes an acid dianhydride including at least pyromellitic dianhydride and 4,4′-benzophenonetetracarboxylic dianhydride, and at least p-phenylenediamine and 4,4′-oxydianiline. An adhesive film, which is a polyimide film obtained using diamine .   The adhesive film according to claim 1, wherein the adhesive layer contains a thermoplastic polyimide.   The adhesive film according to claim 1, wherein the adhesive film can be bonded to the metal foil at a temperature of 300 ° C. or higher.   A method for producing a flexible metal-clad laminate, comprising attaching a metal foil to the adhesive film according to claim 1 using a hot roll laminating apparatus having a pair of metal rolls.   5. A flexible metal-clad laminate according to claim 4, wherein a polyimide film having a thickness of 75 μm or more is disposed as a protective material between the heating roll and the metal foil, and the adhesive film and the metal foil are bonded together. Method.   6. The flexible metal according to claim 5, wherein after bonding the adhesive film and the metal foil, the heating metal is brought into contact with the heating roll for 0.1 second or more in a state where the protective material is disposed on the outside of the metal foil. A method for producing a tension laminate.   After laminating the adhesive film and the metal foil, with the protective material remaining on the outside of the metal foil, under a tension of 1 to 10 N / cm, (lamination temperature -200 ° C.) to (lamination temperature + 100 ° C.) The method for producing a flexible metal-clad laminate according to claim 5 or 6, wherein post-heating treatment is performed in a temperature atmosphere of the following.   A flexible metal-clad laminate obtained by the manufacturing method according to any one of claims 4 to 7, wherein the rate of dimensional change before and after removing the metal foil, and before and after heat treatment at 250 ° C for 30 minutes after removing the metal foil A flexible metal-clad laminate having a total dimensional change rate in the range of -0.05 to + 0.05% in both the MD and TD directions.   When the standard deviation of the dimensional change rate before and after removing the metal foil and the total value of the dimensional change rate before and after performing heat treatment at 250 ° C. for 30 minutes after removing the metal foil is σ, 3σ in both the MD direction and the TD direction is 3σ. The flexible metal-clad laminate according to claim 8, wherein the flexible metal-clad laminate is 0.02 or less.