JP2017177602A - Polyimide laminate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyimide laminate film capable of suppressing crack generation due to alkali environment, when a flexible metal clad laminate is manufactured by using the polyimide laminate film and a flexible printed wiring board is continuously manufactured by a roll-to-roll method.SOLUTION: There is provided a polyamide laminate film using a thermoplastic polyimide by laminating a thermoplastic polyimide layer on at least a single-sided surface of a non-thermoplastic polyimide film. A storage elastic modulus at 300°C and 5 Hz of a thermoplastic polyimide is 1.4×10Pa to 3.5×10Pa, the storage elastic modulus has an inflection point at a higher temperature than a glass transition temperature, and a storage elastic modulus at the inflection point is 0.7×10Pa to 1.6×10Pa.SELECTED DRAWING: None

Description

  The present invention relates to a polyimide laminated film that can be suitably used for a flexible metal-clad laminate.

  In recent years, demand for various flexible printed circuit boards (hereinafter also referred to as FPCs) has been increasing with increasing demand for electronic products such as smartphones, tablet computers, notebook computers, and the like.

  In FPC, for example, an insulating film layer such as polyimide is used as a core film (hereinafter also referred to as a base film or a base material), and a metal foil is provided on the surface of the core film via adhesive layers made of various adhesive materials. It can be obtained by manufacturing a flexible metal-clad laminate bonded by heating and pressure-bonding the layers, and further forming a circuit pattern. Conventionally, an epoxy resin or an acrylic resin has been used for the adhesive layer, but these have poor heat resistance, and use applications are limited. However, a two-layer flexible printed wiring board (hereinafter also referred to as a two-layer FPC) using thermoplastic polyimide as an adhesive layer is expected to further increase demand because of its excellent heat resistance and flexibility.

In addition, there is an increasing demand for weight reduction, miniaturization, and thinning of electronic devices more than ever, and in order to achieve this, it is desired to thin the FPC to be mounted. In addition, with the change in the production process of flexible copper clad laminates due to productivity improvement (cost reduction), demands on the load on materials such as polyimide film, particularly improvement in mechanical strength, are increasing.
In the conventional manufacturing method of FPC, a manufacturing process including a developing process, an etching process, a resist stripping process, and the like is performed in a batch system (non-continuous process). There have been reports on controlling the resistance of polyimide to an alkaline solution used in development, etching treatment, and resist stripping process (for example, Patent Document 1), and disclosure has also been made regarding increasing the strength by increasing the orientation of a polyimide film ( For example, Patent Document 2).

JP 2012-186377 A WO01 / 081456

  As a result of intensive studies by the present inventors, when processing into FPC, there is a step of contacting an alkaline aqueous solution, and alkali resistance is also required. In the roll-to-roll method, which is an example of a continuous method, a load stronger than that in the conventional batch method is applied to the polyimide laminated film and comes into contact with the alkaline aqueous solution. As a result, the problem that a phenomenon such as a crack, a crack, and a tear in the polyimide laminated film that has not been recognized by the alkali treatment in the conventional batch method as disclosed in Patent Document 1 has become apparent.

  In addition, the material disclosed in Patent Document 2 is not enough to withstand the process of continuously manufacturing FPC by the roll-to-roll method as described above, even though it is not a problem in the conventional batch-type FPC manufacturing process. A polyimide material that is sufficient and does not generate cracks even after such a process has not been provided so far.

  This invention was made in view of the above-mentioned subject, Comprising: The polyimide film which can suppress the crack which generate | occur | produces in a film, and a crack and a tear under an alkaline environment in the roll-to-roll type flexible metal laminated board manufacturing process, polyimide It is providing a laminated film and a metal-clad laminate.

As a result of intensive studies in view of the above-mentioned problems, the present inventors have controlled the primary structure and higher-order structure of thermoplastic polyimide by the manufacturing method, and formed an aggregated structure in the resin, so that the film is generated in an alkaline environment. The present inventors have found that cracks (hereinafter also referred to as desmear cracks) that can be suppressed can be suppressed, and the present invention has been completed. That is, this invention relates to the following polyimide laminated films.
1) A polyimide laminated film in which a thermoplastic polyimide layer is laminated on at least one surface of a non-thermoplastic polyimide film, wherein the thermoplastic polyimide layer contains a thermoplastic polyimide, and measured by dynamic viscoelasticity measurement (5 Hz) of the thermoplastic polyimide. The storage elastic modulus at 300 ° C. is 1.4 × 10 ⁸ Pa to 3.5 × 10 ⁸ Pa, and the temperature dependence curve of the storage elastic modulus has an inflection point at a temperature higher than the glass transition temperature of the thermoplastic polyimide. the storage elastic modulus of ^{0.7 × 10 8 Pa~1.6 × 10 8} Pa at the inflection point, a polyimide laminate film which is a thermoplastic polyimide.
2) The polyimide laminated film according to 1), wherein the thermoplastic polyimide has a block component containing at least one of an acid dianhydride component having a rigid component or a diamine having a rigid component.
3) The acid dianhydride having a rigid component contains at least 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and the diamine having a rigid component is 4,4′-diaminodiphenyl ether or 4,4 The polyimide laminated film according to 1) or 2), comprising at least one of '-bis (4-aminophenoxy) biphenyl.

  The polyimide laminated film obtained by this invention can suppress the crack which generate | occur | produces in a polyimide film also in the manufacturing process of a roll-to-roll type continuous FPC.

It is a figure which shows the temperature dependence of the storage elastic modulus of Example 1 of this invention. It is a figure which shows the temperature dependence of the storage elastic modulus of the comparative example 3 of this invention.

  Embodiments of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to each configuration described below, and various modifications can be made within the scope shown in the claims, and technical means disclosed in different embodiments and examples respectively. Embodiments and examples obtained by appropriately combining them are also included in the technical scope of the present invention. In addition, all the academic literatures and patent literatures described in this specification are incorporated by reference in this specification. Unless otherwise specified in this specification, “A to B” indicating a numerical range means “A or more (including A and greater than A) and B or less (including B and less than B)”, respectively.

  The present inventors have found that it is effective for toughness in an alkaline environment that polyimide has a specific primary structure. That is, in order to improve the toughness of the polyimide laminated film in an alkaline environment, in a temperature dependence curve (hereinafter also referred to as a DMA curve) of storage elastic modulus obtained by dynamic viscoelasticity measurement, 340 ° C. to 360 ° It has been found that a multilayer polyimide film in which an adhesive layer is formed of a thermoplastic polyimide having a shoulder portion that attempts to maintain a constant elastic modulus at ° C. has good alkali resistance (desmear resistance). The present inventors have found for the first time that such a molecular design improves toughness in an alkaline environment.

  The thermoplastic polyimide of the present invention refers to one having a glass transition temperature (Tg) of 150 ° C. to 350 ° C. measured by differential scanning calorimetry (DSC).

  The non-thermoplastic polyimide of the present invention generally means a polyimide that does not soften or show adhesiveness even when heated. That is, the non-thermoplastic polyimide of the present invention refers to a polyimide that does not have a glass transition temperature, and refers to a polyimide that does not exhibit a glass transition temperature (Tg) by differential scanning calorimetry (DSC).

(Polyimide laminated film)
The polyimide laminated film of the present invention is a polyimide laminated film in which a thermoplastic polyimide layer is laminated on at least one surface of a non-thermoplastic polyimide film, the thermoplastic polyimide layer containing thermoplastic polyimide, and the dynamic viscosity of the thermoplastic polyimide. storage elastic modulus at 300 ° C. by elasticity measurement (5 Hz) (also referred to as E ') is ^{1.4 × 10 8 Pa~3.5 × 10 8} Pa, the temperature dependence curve of the storage modulus (DMA curve) Has an inflection point (hereinafter sometimes referred to as E 'inflection point) at a temperature higher than the glass transition temperature, and the storage elastic modulus at the inflection point is 0.7 × 10 ⁸ Pa to 1.6 × 10 ^8. It is a polyimide laminated film characterized by being a thermoplastic polyimide which is Pa.

  Here, the dynamic viscoelasticity of the polyimide forming the adhesive layer is obtained by measuring the dynamic viscoelasticity using a film obtained from the polyimide as a test piece and plotting the storage elastic modulus against the temperature. Can do.

The dynamic viscoelasticity measurement is performed under the condition where the measurement frequency is 5 Hz. Preferably the storage modulus of ^{1.4 × 10 8 Pa~3.5 × 10 8} Pa at 300 ° C., more preferably from ^{1.5 × 10 8 Pa~3.2 × 10 8} Pa, More preferably, it is 1.6 × 10 ⁸ Pa to 3.0 × 10 ⁸ Pa. When the storage elastic modulus at 300 ° C. is within this range, it is preferable in that not only the resistance of the desmear liquid but also the hygroscopic solder heat resistance as an adhesive layer is improved.

  It is preferable that the temperature dependence curve (DMA curve) of the storage elastic modulus has an inflection point at a temperature higher than the glass transition temperature of the thermoplastic polyimide. When it has an inflection point, it is easy to express the effect of the aggregation structure.

Preferably the storage modulus at the inflection point of the DMA curve is ^{0.7 × 10 8 Pa~1.6 × 10 8} Pa, it is ^{0.9 × 10 8 Pa~1.5 × 10 8} Pa are more preferable, further preferably ^{0.8 × 10 8 Pa~1.2 × 10 8} Pa. When the storage elastic modulus at the inflection point is within this range, the storage elastic modulus of the aggregate structure showing the effect of suppressing the occurrence of cracks in the desmear liquid is appropriate.

(Thermoplastic polyimide)
The thermoplastic polyimide contained in the thermoplastic polyimide layer in the present invention is obtained by imidizing thermoplastic polyamic acid (hereinafter sometimes referred to as thermoplastic polyamic acid) as a precursor.

The raw material monomer that can constitute the thermoplastic polyamic acid used in the present invention has a storage elastic modulus at 300 ° C. of a thermoplastic polyimide obtained by imidizing a thermoplastic polyamic acid as a precursor at 1.6 × 10 ⁸ Pa- a 3.0 × ¹⁰ 8 Pa, in a temperature higher than the glass transition temperature has an inflection point of the storage modulus, the storage modulus is ^{0.7 × 10 8 Pa~1.6 × 10 8} Pa There is no particular limitation as long as it can be expressed. Diamines and acid dianhydrides commonly used in the synthesis of polyamic acids can be used.

  The diamine is not particularly limited as long as the effects of the present invention can be exhibited, but an aromatic diamine is preferable in terms of heat resistance and the like. For example, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 3,3 '-Diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-oxydianiline, 3,3'-oxydianiline, 3,4'-oxydianiline, 4,4'-diaminodiphenyldiethyl Silane, 4,4′-diaminodiphenylsilane, 4,4′-diaminodiphenylethylphosphine oxide, 4,4′-diaminodiphenyl N-methylamine, 4,4′-diaminodiphenyl N-phenylamine, 1,4- Diaminobenzene (p-phenylenediamine), bis {4- (4-aminophenoxy) pheny } 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 (3-aminophenoxy) benzene, 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis (4-aminophenoxyphenyl) propane Etc., and these can be used alone or in combination.

  The acid dianhydride is not particularly limited as long as the effects of the present invention can be exhibited, but an aromatic acid dianhydride is preferable in terms of heat resistance and the like. For example, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 1,2,5,6 -Naphthalenetetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2 ', 3,3′-benzophenonetetracarboxylic dianhydride, 4,4′-oxyphthalic dianhydride, 3,4′-oxyphthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane Acid dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) propanoic dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ) Ethane dianhydride 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methanoic dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride , Oxydiphthalic acid dianhydride, bis (3,4-dicarboxyphenyl) sulfonic acid dianhydride, p-phenylenebis (trimellitic acid monoester acid anhydride), ethylenebis (trimellitic acid monoester acid anhydride) Bisphenol A bis (trimellitic acid monoester acid anhydride) and the like.

  In the present invention, it is considered that the aggregate structure of the thermoplastic polyimide suppresses the penetration of the desmear liquid and brings about an effect of preventing the occurrence of cracks. The aggregate structure of the present invention means packing of molecular chains having local order. Polyimides are composed of rigid structural units such as aromatic rings or aromatic heterocycles, and therefore have little entanglement and are difficult to form a folded chain like a general polymer. On the other hand, molecular chain packing unique to a molecular chain having an imide ring occurs, and molecular chain packing with the local ordering occurs. The aggregation structure can be controlled by the film forming conditions of the polyimide film and the primary structure of the thermoplastic polyimide. There are various methods for realizing the aggregate structure by the primary structure of the thermoplastic polyimide, but the thermoplastic polyimide has a block component containing at least one of an acid dianhydride component having a rigid component or a diamine having a rigid component. Can also be achieved.

  The acid dianhydride having a rigid component contains at least 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and the diamine having a rigid component is 4,4′-diaminodiphenyl ether or 4,4 ′. More preferably, it contains at least one of -bis (4-aminophenoxy) biphenyl. A compound in which at least one of 4,4′-diaminodiphenyl ether and 4,4′-bis (4-aminophenoxy) biphenyl is bonded to 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. It is particularly preferred.

  Among diamines, particularly when a large amount of rigid paraphenylenediamine or the like is contained in an amount of 70 mol% or more, toughness may be lost due to the rigidity, and the entire thermoplastic polyimide may become brittle. On the other hand, when 2,2-bis [4- (4-aminophenoxy) phenyl] propane or the like is particularly bulky and flexible, the entire thermoplastic polyimide is softened and a sufficient aggregate structure cannot be formed. Therefore, in the present invention, among diamines, 4,4′-diaminodiphenyl ether, 4,4′-bis (4-aminophenoxy) biphenyl, and 1,3-bis (4-aminophenoxy) benzene are included. Particularly preferable among acid dianhydrides, it is particularly preferable to include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride.

(Production of thermoplastic polyamic acid)
As the solvent used in producing the thermoplastic polyamic acid of the present invention, any solvent can be used as long as it dissolves the polyamic acid, but amide solvents, that is, N, N-dimethylformamide, N, N -Dimethylacetamide, N-methyl-2-pyrrolidone and the like, and N, N-dimethylformamide and N, N-dimethylacetamide can be particularly preferably used.

  As the method for producing the thermoplastic polyimide acid of the present invention, any known method can be used as long as it is a thermoplastic polyimide capable of achieving the object of the present application.

For example, the following steps (Aa) to (Ac):
(Aa) a step of reacting an aromatic diamine and an aromatic dianhydride in an organic polar solvent in an excess of aromatic diamine to obtain a prepolymer having amino groups at both ends;
(Ab) a step of additionally adding an aromatic diamine having a structure different from that used in the step (Aa),
(Ac) Further, the aromatic dianhydride having a structure different from that used in the step (Aa) is substantially equal to the aromatic diamine and aromatic dianhydride in all steps. Adding and polymerizing so that
Can be manufactured by.

Alternatively, the following steps (Ba) to (Bc):
(Ba) An aromatic diamine and an aromatic acid dianhydride are reacted in an organic polar solvent in an excess of aromatic acid dianhydride, and a prepolymer having acid anhydride groups at both ends is obtained. Obtaining step,
(Bb) a step of additionally adding an aromatic dianhydride having a structure different from that used in the step (Ba),
(Bc) Furthermore, the aromatic diamine having a different structure from that used in the step (Ba) is used so that the aromatic diamine and the aromatic dianhydride are substantially equimolar in all steps. Adding and polymerizing,
It is also possible to obtain polyamic acid by going through.

  Synthetic methods (for example, steps (Aa) to (Ac), and (A)) in which the order of addition is set so that a specific diamine or acid dianhydride selectively binds to any diamine or acid dianhydride, and ( Ba) to (Bc)) are referred to as sequence polymerization in the present invention. On the other hand, a synthesis method in which the diamine and acid dianhydride to be bonded are not selected in the charging order is referred to as random polymerization in the present invention.

(Solid content concentration of thermoplastic polyamic acid)
The solid content concentration during the production of the thermoplastic polyamic acid of the present invention is not particularly limited, and the polyamic acid having sufficient mechanical strength when used as a non-thermoplastic polyimide is within the range of 5 wt% to 35 wt%. can get.

(Imidization of thermoplastic polyamic acid)
The thermoplastic polyimide produced in the present invention is imidized by various methods such as a chemical imidization method and a thermal imidization method. The chemical imidizing agent contains at least one of a dehydrating agent or an imidization catalyst. Here, the dehydrating agent has a dehydrating cyclization action on polyamic acid, and examples thereof include aliphatic acid anhydrides, aromatic acid anhydrides, N, N′-dialkylcarbodiimides, halogenated lower aliphatics, Halogenated lower fatty acid anhydride, arylphosphonic acid dihalide, thionyl halide, or a mixture of two or more thereof. Among these, from the viewpoint of easy availability and cost, aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and lactic acid anhydride, or a mixture of two or more thereof can be preferably used. The preferable amount of the dehydrating agent is 0.5 mol to 5 mol, preferably 1.0 mol to 4 mol, relative to 1 mol of the amic acid unit in the polyamic acid.

  Moreover, the imidation catalyst means a component having an effect of promoting dehydration and cyclization action on polyamic acid, for example, aliphatic tertiary amine, aromatic tertiary amine, heterocyclic tertiary amine, etc. are used. It is done. Among them, those selected from heterocyclic tertiary amines are particularly preferably used from the viewpoint of reactivity as an imidization catalyst. Specifically, quinoline, isoquinoline, β-picoline, pyridine and the like are preferably used. A preferable amount of the imidation catalyst is 0.05 mol to 3 mol, preferably 0.2 mol to 2 mol, relative to 1 mol of the amic acid unit in the polyamic acid.

  When the dehydrating agent and the imidization catalyst are within these ranges, imidization sufficiently proceeds, and it is possible to reduce the breakage during the production of the imidized film and the decrease in mechanical strength.

(Composition of thermoplastic polyamic acid)
The thermoplastic polyamic acid of the present invention includes various additives such as fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, pigments, dyes, fatty acid esters, and organic lubricants (for example, waxes). Can be added.

(Non-thermoplastic polyimide)
As the polyimide laminated film of the present invention, one having the thermoplastic polyimide layer of the present invention on at least one surface of a non-thermoplastic polyimide film can be used. Hereinafter, examples of the non-thermoplastic polyimide film used in the present invention will be described.

  The diamine and acid dianhydride used for producing the non-thermoplastic polyimide that can be used for the non-thermoplastic polyimide film are not particularly limited. For example, the diamine and acid dianhydride used with a thermoplastic polyamic acid can be illustrated. Among these, diamines include 4,4′-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2′-dimethyl-4,4′-diamino-1,1. '-Biphenyl, 3,3'-dimethyl-4,4'-diamino-1,1'-biphenyl, paraphenylenediamine, 4,4'-bis (4-aminophenoxy) biphenyl, benzophenone as acid dianhydride Tetracarboxylic dianhydride, pyromellitic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and oxydiphthalic acid are preferred from the viewpoint of adhesion to the thermoplastic polyimide layer.

  Polyamic acid which is a precursor of non-thermoplastic polyimide (hereinafter sometimes referred to as non-thermoplastic polyamic acid) is a mixture of diamine and acid dianhydride in an organic solvent so as to be substantially equimolar, It is obtained by heat treatment and reaction. For example, the order of adding the raw material diamine and acid dianhydride is not particularly limited. However, it is possible to control the characteristics of the obtained non-thermoplastic polyimide by controlling not only the chemical structure of the raw material but also the order of addition. The polymerization method, polymerization solvent, reaction temperature and reaction time of the non-thermoplastic polyimide are not particularly limited. There are no particular limitations on the curing agent, curing conditions, and the like when polyamic acid is used as polyimide. Also when making it react, the method of thermal imidation or chemical imidation can be utilized.

  A filler may be added to the non-thermoplastic polyamic acid 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.

  Non-thermoplastic polyimide film obtained by imidizing non-thermoplastic polyamic acid, or thermosetting resin such as epoxy resin and phenoxy resin, polyether ketone, polyether ether ketone as long as the properties as a polyimide laminated film are not impaired A thermoplastic resin such as may be mixed. A known method can be applied to the addition method of these resins.

(Manufacture of polyimide laminated film)
The method for producing the polyimide laminated film is not particularly limited as long as the thermoplastic polyimide layer can be laminated on at least one surface of the non-thermoplastic polyimide film. For example, a method in which a polymer solution containing a thermoplastic polyamic acid is applied to a non-thermoplastic polyimide film followed by heat treatment, or a polymer solution containing a non-thermoplastic polyamic acid and a polymer solution containing a thermoplastic polyamic acid are bonded to a multilayer die. And a method of performing heat treatment by casting on the surface of a support (for example, a metal, ceramic, polymer roll or belt).

  The method for obtaining the non-thermoplastic polyimide film is not particularly limited, and various known methods can be applied. For example, a polymer solution containing non-thermoplastic polyamic acid is cast on the surface of a support (eg, metal, ceramic, polymer roll or belt) to form a polymer solution film. Thereafter, heat treatment is performed as necessary, and the solvent is removed from the polymer solution to obtain a self-supporting film. Further, heat treatment is performed, the imidization reaction is advanced, and a non-thermoplastic polyimide film is produced.

(Flexible metal-clad laminate)
A flexible metal-clad laminate can be produced by bonding the polyimide laminate film of the present invention to a metal foil such as a copper foil. As a manufacturing method of a flexible metal-clad laminate, for example, a hot roll laminating apparatus having a pair of metal rolls or a continuous process using 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. In addition, since a dimensional change is particularly likely to occur when bonded to a metal foil with a hot roll laminating apparatus having a pair of metal rolls, the multilayer polyimide film of the present invention was bonded to the metal foil with a hot roll laminating apparatus. In some cases, a significant effect is exhibited. 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.

(Desmear crack resistance of flexible metal foil laminate)
The polyimide laminated film obtained by the present invention can suppress the occurrence of desmear cracks when a flexible printed wiring board is continuously produced in a roll-to-roll manner. As a method for examining this, in the present invention, the crack resistance of the flexible metal foil laminate when immersed in a desmear solution was evaluated. Those in which cracks were not confirmed even after being immersed in the swelling solution for 15 minutes or more by this method are suitable in that they can suppress the occurrence of cracks caused by an alkaline environment, and cracks were confirmed even after being immersed for 45 minutes or more. Those that have not been performed are particularly suitable.

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

(Dynamic viscoelasticity measurement)
The storage elastic modulus was obtained by measuring the dynamic viscoelasticity in a nitrogen atmosphere with DMS6100 manufactured by SII Nano Technology, and plotting the temperature dependence of the storage elastic modulus.
Sample measurement range; width 9 mm
Distance between grips 20mm
Measurement temperature range: 0 ° C to 400 ° C
Temperature increase rate: 3 ° C./min Strain amplitude: 10 μm
Measurement frequency: 5Hz
Minimum tension / compression force: 100mN
Tension / compression gain; 1.5
Initial value of force amplitude: 100mN
(Crack resistance when dipping in flexible metal foil laminate)
The flexible metal foil laminates obtained in Examples and Comparative Examples were cut into a size of 10 cm in the longitudinal direction and a width of 5 cm, and the metal foil layer on one side of the cut laminate was etched. The test piece was sandwiched between cushion materials and hot-pressed for 90 minutes at 180 ° C. and 17.23 kgf / cm 2. Thereafter, the film was immersed in a swelling liquid kept at 50 ° C. for 90 seconds, desmear liquid kept at 70 ° C. for 600 seconds, and neutralized liquid kept at room temperature for 40 seconds. After soaking, it was washed with water and then dried at 60 ° C. for 10 minutes. Thereafter, the test piece was pressed as follows. First, a test piece was sandwiched between cushion materials, and hot pressing was performed for 90 minutes under the conditions of 180 ° C. and 17.23 kgf / cm 2. At this time, an FR4 substrate having 1.0 cm × 2.5 cm × 8 holes cut out was used. The above test piece was immersed in the swelling solution for 90 seconds, and then cut into a size of 2.2 cm × 5.0 cm for each hole of the FR4 substrate to obtain a test piece for measurement. The test piece for measurement was immersed in a desmear liquid maintained at 70 ° C. for a predetermined time (15, 30, 45, 60 minutes), and then sequentially immersed in a neutralizing liquid maintained at room temperature for 40 seconds. After immersing, the FR4 cavity portion in the test piece washed with water and dried at 60 ° C. for 10 minutes was used for observation. Observation was carried out using an optical microscope to determine the presence or absence of cracks at 50 to 200 times. ◎ if no crack was confirmed even if immersed in the swelling liquid for 45 minutes or more, ○ if no crack was confirmed even if immersed for 15 minutes or more, crack was confirmed when immersed for 15 minutes Was marked with x.

(Hygroscopic solder heat resistance of flexible metal-clad laminates)
The double-sided flexible metal-clad laminates obtained in the examples and comparative examples were cut into 3.5 cm squares, and one side (for convenience, the A side) had a 2.5 cm square copper foil layer left in the center of the sample. On the opposite side (for convenience, B side), five samples were prepared by removing the excess copper foil layer by etching treatment so that the copper foil layer remained on the entire surface. The resulting sample was 85 ° C., 85% R.D. H. The sample was left for 72 hours under the humidification conditions, and a moisture absorption treatment was performed. After the moisture absorption treatment, the sample was immersed in a 300 ° C. solder bath for 10 seconds. For the sample after solder immersion, the copper foil layer on the B side is completely removed by etching, and if the appearance of the part where the copper foil overlaps is not changed, ○ (good), whitening of the multilayer polyimide layer, swelling, copper When any peeling of the foil layer was confirmed, it was set as x (bad).

(Synthesis of thermoplastic polyimide precursor)
(Synthesis Example 1)
With the reaction system maintained at 20 ° C., 12.25 g of ODA was added to 321.68 g of DMF. Subsequently, 22.54 g of BAPB was added, and 25.20 g of BPDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BPDA was dissolved, 7.21 g of PMDA was added and stirred for 30 minutes. A solution in which 0.80 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to the increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 2)
With the reaction system kept at 20 ° C., 12.25 g of ODA was added to 32.68 g of DMF, and 16.20 g of BPDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BPDA was dissolved, 22.54 g of BAPB was added. Subsequently, 9.00 g of BPDA was gradually added, and then 7.21 g of PMDA was added and stirred for 30 minutes. A solution in which 0.80 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to the increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by sequence polymerization.

(Synthesis Example 3)
With the reaction system maintained at 20 ° C., 10.93 g of ODA was added to 321.77 g of DMF. Subsequently, 20.11 g of BAPB was added, and 21.41 g of BPDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BPDA was dissolved, 4.98 g of BAPP was added. Subsequently, 9.79 g of PMDA was added and stirred for 30 minutes. A solution in which 0.79 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the reaction solution while paying attention to increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by sequence polymerization.

(Synthesis Example 4)
With the reaction system kept at 20 ° C., 7.12 g of ODA was added to 322.01 g of DMF. Subsequently, 21.82 g of BAPB was added, and 6.92 g of TPE-R was added. Thereafter, 24.40 g of BPDA was gradually added while stirring in a nitrogen atmosphere. After visually confirming that BPDA was dissolved, PMDA 6.98 was added and stirred for 30 minutes. A solution in which 0.78 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to an increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 5)
While maintaining the inside of the reaction system at 20 ° C., 9.64 g of ODA was added to 321.85 g of DMF. Subsequently, 22.17 g of BAPB was added, and 3.51 g of TPE-R was added. Thereafter, 24.79 g of BPDA was gradually added while stirring in a nitrogen atmosphere. After visually confirming that BPDA was dissolved, PMDA 7.09 was added and stirred for 30 minutes. A solution in which 0.79 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the reaction solution while paying attention to increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 6)
With the reaction system kept at 20 ° C., 9.97 g of ODA was added to 321.51 g of DMF. Subsequently, 22.92 g of BAPB was added, and 1.35 g of PDA was added. Thereafter, 25.63 g of BPDA was gradually added while stirring in a nitrogen atmosphere. After visually confirming that BPDA was dissolved, PMDA 7.33 was added and stirred for 30 minutes. A solution in which 0.81 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the reaction solution while paying attention to an increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 7)
With the reaction system kept at 20 ° C., 7.9 g of ODA was added to 300.78 g of DMF. Subsequently, 19.60 g of BAPB was added, and 4.31 g of PDA was added. Thereafter, 27.39 g of BPDA was gradually added while stirring in a nitrogen atmosphere. After visually confirming that BPDA was dissolved, PMDA 7.83 was added and stirred for 30 minutes. A solution in which 0.87 g of PMDA was dissolved in DMF so as to have a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 8)
With the reaction system kept at 20 ° C., ODA 9.78 g was added to DMF 321.70 g. Subsequently, 22.49 g of BAPB was added, and 2.59 g of m-TB was added. Thereafter, 25.15 g of BPDA was gradually added while stirring in a nitrogen atmosphere. After visually confirming that BPDA was dissolved, PMDA 7.19 was added and stirred for 30 minutes. A solution in which 0.80 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to the increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 9)
With the reaction system maintained at 20 ° C., 22.54 g of BAPB was added to 32.68 g of DMF, and 16.20 g of BPDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BPDA was dissolved, 12.25 g of ODA was added. Subsequently, 9.00 g of BPDA was gradually added, and then 7.21 g of PMDA was added and stirred for 30 minutes. A solution in which 0.80 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to the increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by sequence polymerization.

(Synthesis Example 10)
With the inside of the reaction system kept at 20 ° C., 12.60 g of ODA was added to 32.39 g of DMF. Subsequently, 13.91 g of BAPB was added, and 7.35 g of TPE-R was added. Thereafter, 25.91 g of BPDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BPDA was dissolved, PMDA 6.98 was added and stirred for 30 minutes. A solution prepared by dissolving 0.82 g of PMDA in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 11)
With the reaction system maintained at 20 ° C., 18.26 g of ODA was added to 321.02 g of DMF. Subsequently, 14.40 g of BAPB was added, and 26.82 g of BPDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BPDA was dissolved, 7.67 g of PMDA was added and stirred for 30 minutes. A solution in which 0.85 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to an increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 12)
With the reaction system kept at 20 ° C., 6.93 g of ODA was added to 322.27 g of DMF. Subsequently, 29.76 g of BAPB was added, and 23.76 g of BPDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BPDA was dissolved, 6.79 g of PMDA was added and stirred for 30 minutes. A solution prepared by dissolving 0.76 g of PMDA in DMF so that the solid content concentration is 7.2% is prepared, and this solution is gradually added to the above reaction solution while paying attention to increase in viscosity, so that the viscosity becomes 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis Example 13)
With the reaction system kept at 20 ° C., 9.50 g of ODA was added to 322.00 g of DMF. Subsequently, 17.48 g of BAPB was added, and 20.94 g of BPDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BPDA was dissolved, 9.74 g of BAPP was added. Subsequently, 9.57 g of PMDA was added and stirred for 30 minutes. A solution in which 0.78 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to an increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by sequence polymerization.

(Synthesis Example 14)
With the reaction system kept at 20 ° C., 10.78 g of ODA was added to 321.91 g of DMF. Subsequently, 19.84 g of BAPB was added, and 4.91 g of BAPP was added. Thereafter, 24.64 g of BPDA was gradually added while stirring in a nitrogen atmosphere. After visually confirming that BPDA was dissolved, PMDA 7.05 was added and stirred for 30 minutes. A solution in which 0.78 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to an increase in viscosity, so that the viscosity became 800 poise. The polymerization was terminated when reached. The obtained thermoplastic polyimide precursor was synthesized by random polymerization.

(Synthesis of non-thermoplastic polyimide precursor)
(Synthesis Example 15)
With the reaction system kept at 20 ° C., 10.53 g of ODA was added to 657.82 g of DMF. Subsequently, 32.39 g of BAPP was added, and 16.95 g of BTDA was gradually added while stirring under a nitrogen atmosphere. After visually confirming that BTDA was dissolved, 14.34 g of PMDA was added, and then 14.22 g of PDA and 29.83 g of PMDA were added, followed by stirring for 30 minutes. A solution in which 1.72 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to increase in viscosity, so that the viscosity became 2000 poise. The polymerization was terminated when reached.

  To this polyamic acid solution, an imidization accelerator consisting of acetic anhydride / isoquinoline / DMF (weight ratio 2.0 / 0.6 / 2.8) was added at a weight ratio of 50% with respect to the polyamic acid solution. The mixture was stirred with a mixer, extruded from a T die, and cast onto a stainless steel endless belt. This resin film is heated at 130 ° C. for 90 seconds, and then the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip. At 250 ° C. for 11 seconds, 350 ° C. for 11 seconds, 450 ° C. for 120 seconds. Drying and imidization were performed to obtain a polyimide film having a thickness of 12.5 μm.

  Table 1 shows the monomer addition order (molar ratio), polymerization method, and glass transition temperature (Tg) of Synthesis Examples 1 to 15.

Example 1
On both surfaces of the polyimide film obtained in Synthesis Example 15, the polyamic acid solution obtained in Synthesis Example 1 was applied so that the final single-sided thickness was 3.0 μm, and 150 ° C. × 68 seconds, 80 ° C. × 9 seconds. And dried. Subsequently, imidization was performed by heating at 340 ° C. for 12 seconds to obtain a laminated polyimide film having a total thickness of 18.5 μm.

  Lamination temperature 360 using 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) on both sides of the obtained laminated polyimide film, and using protective films (Apical 125 NPI; manufactured by Kaneka) on both sides of the copper foil. Thermal lamination was performed under the conditions of ° C., laminating pressure of 265 N / cm (27 kgf / cm), and laminating speed of 1.0 m / min to prepare a flexible metal foil laminate. The hygroscopic solder heat resistance of the obtained flexible metal-clad laminate was evaluated. The results are shown in Table 2.

  Subsequently, the polyamic acid solution obtained in Synthesis Example 1 was applied to an aluminum foil using a comma coater and dried at 120 ° C. for 180 seconds. Then, the polyimide film of the contact bonding layer was obtained by heating at 250 degreeC for 60 second, and also heating at 350 degreeC for 200 second, and etching the aluminum foil of a base material. The storage elastic modulus of the obtained polyimide film was measured. The results are shown in Table 2.

(Example 2 to Comparative Example 6)
Except for changing the thermoplastic polyimide precursor to Synthesis Example 2 to Synthesis Example 14, the same procedure as in Example 1 was carried out to prepare a flexible metal foil laminate / adhesive layer polyimide film, moisture absorption solder heat resistance evaluation, and storage elastic modulus. Was measured. The results are shown in Table 2.

(Discussion)
From the results of Table 2, the storage elastic modulus temperature dependency curve (DMA curve) has an inflection point at a temperature higher than the glass transition temperature, and the storage elastic modulus at the inflection point is 0.7 × 10 ⁸ Pa-1. It can be seen that the thermoplastic polyimide of .6 × 10 ⁸ Pa is excellent in desmear crack resistance.

1. 1. The shoulder portion of the storage elastic modulus obtained from the dynamic viscoelasticity measurement of the present invention. Inflection point of storage modulus obtained from dynamic viscoelasticity measurement of the present invention

Claims (3)

A polyimide laminated film in which a thermoplastic polyimide layer is laminated on at least one surface of a non-thermoplastic polyimide film, the thermoplastic polyimide layer containing a thermoplastic polyimide, and 300 ° C. by dynamic viscoelasticity measurement (5 Hz) of the thermoplastic polyimide. The storage elastic modulus of the resin is 1.4 × 10 ⁸ Pa to 3.5 × 10 ⁸ Pa, and the temperature dependence curve of the storage elastic modulus has an inflection point at a temperature higher than the glass transition temperature of the thermoplastic polyimide, storage modulus at the inflection point is ^{0.7 × 10 8 Pa~1.6 × 10 8} Pa, polyimide laminate film which is a thermoplastic polyimide.   The polyimide laminated film according to claim 1, wherein the thermoplastic polyimide has a block component containing at least one of an acid dianhydride component having a rigid component or a diamine having a rigid component. The acid dianhydride having a rigid component contains at least 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and the diamine having a rigid component is 4,4′-diaminodiphenyl ether or 4,4′- The polyimide laminated film according to claim 1, comprising at least one of bis (4-aminophenoxy) biphenyl.