TWI448488B - A polyimide precursor resin solution - Google Patents

Description

Polyimine precursor resin solution

The present invention relates to a polybendimimine precursor resin solution containing a polyimide intermediate precursor resin.

Polyimine is useful for applications in the electronics field and is used as an insulating film or protective coating on semiconductor devices. In particular, the wholly aromatic polyimine has a large contribution to high density, multi-function, and the like of a flexible circuit board or an integrated circuit due to its excellent heat resistance, mechanical properties, and electrical properties. As described above, when an interlayer insulating film or a protective film of a fine circuit is formed, a solution of a polyimide precursor is used in the past. Such a polyimide precursor solution is known as a solution of a polyamic acid obtained by reacting a diamine compound with a tetracarboxylic dianhydride, or a polyphthalate, polymethyl phthalate. Various solutions of esters, poly(p-guanidine) and the like. The polyimine precursor solution is a solution of a polymer having a high degree of polymerization. When a polyimide film is obtained from a polymer solution, the polymer solution is generally applied to copper or glass. The substrate is heated and heated to carry out solvent removal and hydrazine imidization to obtain a polyimide film. However, when the polymer solution having a high degree of polymerization is applied, since the degree of polymerization is high, in order to make the solution a coatable viscosity, there is a problem that it is necessary to lower the concentration of the solute. Further, when the solute concentration is increased in order to improve the productivity, the viscosity of the solution is increased, and there is a problem that the coating cannot be applied, and if the solute concentration is high, the polymer is made to have a low molecular weight in order to achieve a coatable viscosity. There is a problem that a coating film or film having excellent mechanical properties and thermal properties cannot be obtained. Furthermore, the polymer solution is difficult to withstand long-term storage, and it is extremely difficult to store it for a long period of time while maintaining its degree of polymerization.

In order to solve the above problems, for example, Patent Document 1 discloses a polyimine precursor solution obtained by adding a substantially monomolar diamine to a polyimine precursor having a dicarboxylic acid terminal.

Patent Document 2 discloses a high-concentration and low-viscosity polyimine precursor resin obtained by adding water during polymerization of a resin.

Patent Document 3 discloses a polybendimimine precursor solution obtained by adding a tetracarboxylic acid compound to a polyimine precursor precursor resin having an amine terminal. In this document, it is preferred that the amount of the tetracarboxylic acid compound added is excessively added, and in the examples, the tetracarboxylic acid compound is also excessively added.

Patent Document 4 discloses a polyilylimide precursor resin solution obtained by adding a diamine and/or an isocyanate compound to a polyimide precursor having a carboxylic acid terminal.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2001-31764

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-221398

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2010-1412

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2009-280661

The polyimine precursor solution disclosed in the above Patent Document 1 is obtained by adding a substantially monomolar diamine to a polyamidiamine precursor resin having a dicarboxylic acid terminal. At this time, when the reaction proceeds slowly, gelation of the varnish occurs, and the storage stability of the resin liquid may be lowered. Further, it is considered that the carboxylic acid terminal is remarkably lower in reactivity than the acid anhydride terminal, and the added diamine remains in the unreacted state in the resin liquid. Therefore, the diamine is oxidatively deteriorated and does not sufficiently react with the terminal of the dicarboxylic acid, and there is also a problem that a high molecular weight polyimine is not obtained.

Further, as described in Patent Document 2, when water is added during polymerization or after polymerization, the indole bond in the molecule of the polyimide precursor is hydrolyzed, and the storage stability of the polyimide precursor resin is lowered. The problem. Further, since the polymethylene imine precursor resin has a low molecular weight, the viscosity of the resin solution or the film forming property may be lowered, and a uniform coating film may not be obtained, and the film may be reduced in molecular weight. The problem of low physical properties of the amine film.

Further, as described in Patent Document 3, when a tetracarboxylic acid compound is excessively added, there is a high possibility that an unreacted tetracarboxylic acid compound remains in the solution during processing, and may become a foreign matter due to carbonization of high-temperature processing in the production step. As a result, there is a problem that the physical properties of the polyimide film are lowered.

Further, as the polyimine precursor resin solution disclosed in Patent Document 4, the reaction proceeds slowly by adding a substantially equimolar diamine monomer to the polyimine imide precursor resin having a carboxylic acid terminal, and the resin liquid The preservation stability may be low. Further, the carboxylic acid terminal is remarkably low in reactivity compared to the acid anhydride terminal, and it is considered that the added diamine remains in the unreacted state in the resin liquid. Therefore, the diamine is oxidatively deteriorated and does not sufficiently react with the carboxylic acid terminal, and there is a problem that a high molecular weight polyimine cannot be obtained.

In view of the above circumstances, an object of the present invention is to provide a polyilylimide precursor resin solution, which can obtain a polyimide film coating film having good physical properties, and has a high concentration and a low viscosity, and combines workability and storage stability. .

In order to solve the above-mentioned problems, the inventors of the present invention have found that a solution containing a polyimine precursor resin having a specific structure at one end and one carboxylic acid terminal at both ends can solve the above problems. The present invention has been completed.

That is, the present invention is as follows.

[1] A polyimine precursor resin solution comprising a polyamidene precursor resin represented by the following formula (1).

(In the formula (1), R ₁ represents a tetravalent organic group, R ₂ represents a divalent organic group, and R ₃ and R _{4 are} each the same or different, and represent a hydrogen atom or a monovalent organic group, and R ₅ represents The organic group of 3 valence, n represents an integer of 2 or more.)

[2] The polyimine precursor resin solution of [1], wherein the polyimine precursor resin is an amine-terminated polyimide precursor resin represented by the following formula (2) and the following formula ( 3) Resin obtained by reacting a tricarboxylic anhydride:

Formula (2)

(In the formula (2), R ₁ to R ₄ and n are synonymous with the above.).

Formula (3)

(In the formula (3), R ₅ is synonymous with the foregoing.).

[3] The polyimine precursor resin solution of [1] or [2], wherein R ₁ is selected from any one of the structures represented by the following formula (4):

[4] The polyimine precursor resin solution of [1] or [2], wherein R ₂ is selected from any one of the structures represented by the following formula (5):

[5] The polyimine precursor resin solution of [1] or [2], wherein R ₃ and R _{4 are} at least one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group and a phenyl group.

[6] The polyimine precursor resin solution according to [1] or [2], wherein R ₅ is selected from one or more of the structures represented by the following formula (6):

[7] The polyimine precursor resin solution according to [2], wherein the tricarboxylic acid is 0.3 to 0.7 times (mole ratio) relative to the terminal diamine of the amine terminal polyimine precursor resin. Anhydride reaction.

[8] A polyimide film of a polyimine resin obtained by hardening a solution of the polyimide precursor resin of any one of [1] to [7].

[9] A metal-clad laminate comprising a polyimine resin coating film as in [8] laminated on a metal foil.

[10] A flexible printed circuit board obtained by using a metal-clad laminate such as [9].

The polythenimine precursor resin solution of the present invention has a high concentration and a low viscosity, and is also excellent in storage stability.

Since the polythenimine precursor resin solution of the present invention has a high concentration and a low viscosity, it is excellent in workability in producing a polyimide film of a polyimide film.

In addition, the polyimine resin coating film obtained by curing the polyimine precursor resin solution of the present invention is excellent in balance of various physical properties such as strength, elongation, linear expansion coefficient, and adhesion.

[Formation of the Invention]

The form in which the present invention is carried out (hereinafter referred to as "this embodiment") will be described in detail below. The present invention is not limited to the embodiments described below, and various modifications can be made without departing from the spirit and scope of the invention.

The polyimine precursor resin solution of the present embodiment contains a polyimine precursor resin represented by the following formula (1).

(In the formula (1), R ₁ represents a tetravalent organic group, R ₂ represents a divalent organic group, and R ₃ and R _{4 are} each the same or different and represent a hydrogen atom or a monovalent organic group, and R ₅ represents a trivalent group. The organic group, n represents an integer of 2 or more).

A polyimine precursor resin having the structure represented by the above formula (1), wherein one of the molecular terminals is an amine terminal and the other molecule is a carboxylic acid terminal, and therefore, the heating is carried out in the molecule due to the imidization The formation of a guanamine bond between each other is characterized by an increase in molecular weight. Therefore, the solution containing the polyimine precursor resin having the above structure has a low molecular weight before the imidization, and has a high concentration and a low viscosity, so that the workability is excellent, and the molecular weight is increased after the imidization of the medium. The advantages of physical properties such as strength.

Further, since the polyimine precursor resin solution of the present embodiment does not require a monomer which coexists with an amine compound or a carboxylic acid compound, it is not necessary to cause the reaction to proceed slowly during the storage of the solution, and varnish gelation occurs. The storage stability is significantly superior.

Each symbol in the formula (1) will be described below. R ₁ represents a tetravalent organic group, and may be any one of an aromatic structure and an alicyclic structure, and is, for example, one or more selected from the structures represented by the following formula (4).

In the case of R ₁ , any one or more of the organic groups represented by the following structures are preferable from the viewpoint of adhesion and dimensional stability.

R ₂ represents a divalent organic group, and may be any one of an aromatic structure and an alicyclic structure, and is, for example, one or more selected from the structures represented by the following formula (5).

R _{2 is} preferably one or more organic groups represented by the following structures from the viewpoint of adhesion and dimensional stability.

R ₃ and R _{4 are} each the same or different and represent a hydrogen atom or a monovalent organic group. The monovalent organic group may be any of an aromatic structure, an alicyclic structure, or an aliphatic structure, such as a methyl group, an ethyl group, a phenyl group or the like.

R ₅ represents a trivalent organic group, and may be any one of an aromatic structure, an alicyclic structure, and an aliphatic structure, and is, for example, one or more selected from the structures represented by the following formula (6).

In the case of R ₅ , from the viewpoint of availability and cost, an organic group represented by the following structure is preferred.

n represents an integer of 2 or more, and is preferably an integer of 2 to 400, more preferably 50 to 350, and still more preferably 100 to 250.

The polyimine precursor resin solution of the present embodiment is obtained by dissolving the polyamidene precursor resin represented by the above formula (1) in a solvent. Here, the solvent is not particularly limited as long as it can dissolve the resin represented by the formula (1), and examples thereof include an aprotic polar compound, an ether compound, a water-soluble alcohol compound, a water-insoluble alcohol compound, and a ketone compound.

Aprotic polar compounds, specifically, for example, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl hydrazine, hexamethyl phosphate Tridecylamine, etc., ether compounds such as 2-methoxyethanol, 2-ethoxyethanol, 2-(methoxymethoxy)ethoxyethanol, 2-isopropoxyethanol, 2-butyl Oxyethanol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monoethyl ether, tetraethyl Glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, polyethylene glycol, Polypropylene glycol, tetrahydrofuran, two Alkane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, etc., water-soluble alcohol-based compounds, such as: methanol, ethanol, 1-propanol, 2-propanol , tert-butanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5- Pentylene glycol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, 1,2,6-hexanetriol, diacetone alcohol, etc., water-insoluble alcohol compound For example, benzyl alcohol or the like, a ketone compound such as 1,5,5-trimethyl-3-cyclohexanone or the like. Further, other solvents such as γ-butyrolactone and the like. These solvents may be used singly or in combination of two or more.

Among the above, preferred solvents are, for individual solvents, such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, diethylene glycol monomethyl The ether is, for example, a combination of N-methylpyrrolidone and diethylene glycol monomethyl ether, N-methylpyrrolidone and methanol, N-methylpyrrolidone and 2-methoxyethanol.

The content of the solvent is preferably 70 to 90% by mass based on the resin component containing the polyimide precursor resin. By setting the content of the solvent to 70 to 90% by mass, the varnish viscosity excellent in coatability can be obtained.

The solid content concentration of the polyamidene precursor resin solution in the present embodiment is preferably from 10 to 30% by mass, more preferably from 15 to 30% by mass, even more preferably from 20 to 30% by mass, from the viewpoint of workability. When the solid content concentration is less than 10% by mass, the drying shrinkage during processing of the polyimide film of the polyimide film tends to increase, and the workability (productivity) tends to be deteriorated. If it exceeds 30% by mass, the viscosity of the solution may excessively rise. Processability tends to deteriorate.

The viscosity of the polyamidene precursor resin solution in the present embodiment is preferably from 1,000 to 25,000 cP, more preferably from 2,000 to 15,000 cP, still more preferably from 2,000 to 10,000 cP. When the viscosity is less than 1000 cP, the productivity of the polyimide film of the polyimide film tends to deteriorate, and if it exceeds 25,000 cP, the workability tends to deteriorate.

The polyimine precursor precursor resin in the present embodiment can be obtained, for example, by reacting an amine-terminated polyimide precursor resin represented by the following formula (2) with a tricarboxylic anhydride represented by the following formula (3):

Formula (2)

(In the formula (2), R ₁ to R ₄ and n are synonymous with the above.)

Formula (3)

(In the formula (3), R ₅ is synonymous with the foregoing.).

In the above reaction, the reaction conditions are not particularly limited, and a tricarboxylic acid anhydride may be added to a solution in which an amine-terminated polyimide precursor resin is dissolved, and the mixed solution is stirred at a reaction temperature of 5 to 40 ° C for 0.5 to 8 hours to cause a reaction. .

The solvent for dissolving the amine-terminated polyimide precursor resin is not particularly limited, and examples thereof include an aprotic polar compound, an ether compound, a water-soluble alcohol compound, a water-insoluble alcohol compound, and a ketone compound. Among them, N-methylpyrrolidone and N,N-dimethylacetamide are aprotic polar compounds from the viewpoint of solubility and ease of availability.

In the above reaction, it is preferred to add a small amount of a tricarboxylic anhydride to the terminal diamine of the amine-terminated polyimide precursor resin and to react. By making the amount of the monocarboxylic acid of the tricarboxylic anhydride smaller than the terminal diamine of the amine-terminated polyimide precursor resin, the tricarboxylic anhydride can remain in the monomer solution in the monomer solution for the polyimine. The precursor resin is introduced into the carboxylic acid end. As a result, since the reactivity of the carboxylic acid is lower than that of the monomer state, it is difficult to cause a reaction with time, whereby the storage stability of the resin liquid is improved. Further, when the tricarboxylic acid anhydride does not remain in the monomer state in the monomer state, the adhesion of the polyimide film obtained by curing the polyimide film of the polyimide precursor tends to be improved.

In the above reaction, the reaction of the tricarboxylic anhydride with a terminal diamine of the amine-terminated polyimide precursor resin of 0.3 to 0.7 times (mole ratio) is more preferable. When the amount of the terminal diamine of the tricarboxylic acid anhydride relative to the amine-terminated polyimide precursor resin is in the above range, the amount of the tricarboxylic anhydride remaining in the monomer state can be reduced, and at the same time, it can be produced with good efficiency. A polyimine precursor resin in which the end of the molecule is an amine end and the other end is a carboxylic acid end. The amount of the tricarboxylic acid anhydride relative to the terminal diamine of the amine-terminated polyimide precursor resin is more preferably 0.4 to 0.6 times.

When the polyimine precursor resin is produced by the above method, the solution containing the polyimide precursor resin after the reaction can be directly used as the polyimide intermediate resin solution in the present embodiment. In this case, the polyimine precursor resin solution may contain, in addition to the amine-terminated polyimide precursor resin and the tricarboxylic anhydride as a raw material, and the polyimine precursor resin as a product, The carboxylic acid terminal polyimine precursor resin represented by the formula (4) is a carboxylic acid.

(In the formula (4), R ₁ to R ₅ and n are synonymous with the above.)

In the case of the ratio of each compound contained in the solution at this time, when the content ratio of each compound is inferred by the reaction theory, it is considered that the formula (1)>formula (4) Formula (2)> Formula (3).

In the reaction for producing a polyimide precursor resin, the amine terminal polyimine precursor resin represented by the following formula (2) which is a raw material

Formula (2)

(In the formula (2), R ₁ to R ₄ and n are synonymous with the above.) An acid component such as tetracarboxylic dianhydride or tetracarboxylic acid ester, and a diamine compound can be used as known (solution polymerization). The method is obtained by polycondensation. As the acid component, tetracarboxylic dianhydride is preferably used from the viewpoint of reactivity.

As the tetracarboxylic dianhydride and the diamine compound, any of an aliphatic compound and an aromatic compound can be used, and from the viewpoint of heat resistance, an aromatic compound is preferably used.

The aromatic tetracarboxylic dianhydride is not particularly limited, and examples thereof include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 3,3',4,4'-diphenyl. A ketone tetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3', 4,4'-diphenylphosphonium tetracarboxylic dianhydride or the like. Among the above, 3,3',4,4'-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride are preferred from the viewpoint of price or ease of availability.

The aromatic diamine compound is not particularly limited, and examples thereof include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminobiphenyl, and 4,4'-diamino group- 2,2'-bis(trifluoromethyl)biphenyl, 3,3'-diaminodiphenylanthracene, 4,4'-diaminodiphenylanthracene, 4,4'-diaminodiyl Phenyl sulfide, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diamino group Diphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy) Benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]anthracene, bis[4-(3-aminophenoxy) Phenyl]anthracene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoro Propane, etc. Among the above, p-phenylenediamine, 4,4'-diaminodiphenyl ether, and 1,3-bis(4-aminophenoxy)benzene are preferred from the viewpoint of price or ease of availability.

The tetracarboxylic dianhydride and the diamine compound may be used singly or in combination of two or more.

In the present embodiment, for example, tetracarboxylic dianhydride (1.0 mol) is slowly added to a solution obtained by dissolving a diamine compound (0.95 mol) in a solvent at room temperature to 30 ° C at room temperature. The mixture was stirred for 0.5 hour or more, whereby an amine-terminated polyimide precursor resin was obtained. In this case, the tetracarboxylic dianhydride may be added in a dispersed state without dissolving the diamine compound, and the diamine compound may be added in a dissolved or dispersed state after the tetracarboxylic dianhydride is added to the solvent. Thereafter, an amine-terminated polyimide precursor resin can be obtained by stirring at room temperature for 0.5 hour or more. Further, when the stirring temperature is in the range of -10 ° C to the boiling point of the solvent, and the stirring time is 0.5 hour or longer, the amine-terminated polyimide precursor resin of the present embodiment can also be obtained.

When the amine-terminated polyimide precursor resin is produced by the above method, the solution of the amine-containing terminal polyimide precursor resin after the reaction can be directly used as a raw material in the reaction for producing a polyimide precursor resin, or The amine-terminated polyimide precursor resin was added dropwise to the poor solvent of the amine-terminated polyimide precursor resin, and the polymer was analyzed, separated by filtration, and purified.

Further, in the reaction for producing a polyimine precursor resin, a tricarboxylic acid anhydride represented by the following formula (3) which is a raw material

The production method of (in the formula (3), R ₅ is synonymous with the above) can be produced according to a known method, and a commercially available product can also be used. Specific examples of the tricarboxylic acid anhydride include trimellitic anhydride and cyclohexane tricarboxylic anhydride. Among them, trimellitic anhydride is preferred from the viewpoint of availability.

Further, the polyamidene precursor resin solution of the present embodiment may contain a known additive. Such an additive is, for example, a tertiary amine such as pyridine or an acid anhydride such as acetic anhydride, or a coating agent such as a quinone imidization accelerator or a surfactant. Further, in the polyamidene precursor resin solution of the present embodiment, in order to obtain more excellent flame retardancy, a flame retardant may be blended. The flame retardant is, for example, an inorganic filler such as aluminum hydroxide, cerium oxide or barium sulfate, or an organic phosphorus compound such as a phosphate. Further, in the polyamidene precursor resin solution of the present embodiment, a lubricating material such as an inorganic filler may be blended in order to obtain more excellent slidability. The inorganic filler is, for example, cerium oxide, talc, calcium phosphate or the like. These may be used alone or in combination.

[Polyimide resin coating film]

By curing the polyimine precursor resin solution in the present embodiment, a polyimide film coating film can be obtained. Specifically, it can be obtained by coating a polyimide polyimide precursor resin solution on a substrate such as copper, aluminum, or glass and heating it to carry out oxime imidization. The hydrazine imidization temperature is 200 ° C or higher, preferably 250 ° C or higher, more preferably 300 ° C or higher, and heating for 5 minutes or longer, preferably 30 minutes or longer. The polyimide film of the polyimide may be used in the form of a polyimide coating in close contact with the substrate, or may be used as a polyimide film in the form of a polyimide film.

When the polyimide film is formed from a polyimine precursor resin solution, it can be removed by extrusion from a slit nozzle or by coating on a substrate with a bar coater or the like to remove the solvent, and then removing the solvent. After imidization, it is produced by peeling off from a base material. In order to obtain a polyimide pigment solution, the polyimide film is applied to a substrate by a conventional spin coating method, a spray coating method, a dipping method, or the like, and dried to remove the solvent, and then the imide is removed. Chemical.

The polyimine precursor resin solution of the present embodiment, the film and the coating obtained therefrom, for example, can be used for producing a film for FPC (Flexible Printed Substrate), a heat-resistant insulating tape, a heat-resistant adhesive tape, and a high-density magnetic film. Record substrates, capacitors, and the like. Further, for example, a sliding member filled with a fluororesin or graphite, a structural member reinforced with glass fibers or carbon fibers, a bobbin of a small coil, a sleeve, and a tube for end-insulation are molded or molded. Moreover, the manufacture of a laminated material such as an insulating spacer of a power transistor, a magnetic head spacer, a spacer of a power relay, and a spacer of a transformer. Further, it can be used for manufacturing enamel coating materials such as electric wires, cable insulation coating films, solar cells, low temperature storage tanks, space heat insulating materials, integrated circuits, and slot liners. Moreover, it can be used for the manufacture of an ultrafiltration membrane, a reverse osmosis membrane, and a gas separation membrane. Further, it is also possible to use a yarn, a woven fabric, a nonwoven fabric or the like which has heat resistance.

[Metal coated laminate]

The metal-clad laminate of the present embodiment is obtained by laminating a polyimide film obtained by curing the polyimine precursor resin solution on a metal foil.

The metal-clad laminate may be a three-layer flexible metal laminate composed of a metal foil, a polyimide resin layer, and an adhesive layer, or may be composed of a metal foil and a polyimide resin layer. The two-layer flexible metal laminate is preferably a two-layer flexible metal laminate from the viewpoint of heat resistance, dimensional stability, and weight reduction.

A metal foil such as a copper foil, a SUS foil, an aluminum foil or the like is preferable from the viewpoint of conductivity and circuit workability. Further, when a metal foil is used, an organic surface treatment such as an inorganic surface treatment such as galvanization or chrome plating or a decane coupling agent may be applied.

The two-layer flexible metal laminate of the present embodiment can be produced, for example, by a method comprising the steps of: applying a polyimide polyimide precursor resin solution to a metal foil; and applying the coating to the metal foil. The polyimine precursor resin solution is dried; the temperature is raised to 330 to 400 ° C to obtain a polyimine resin layer.

In the coating step, the thickness of the coating layer formed on the metal foil may be appropriately set between 2 and 150 μm depending on the application. The coating method may suitably employ a comma coater, a gravure coater, or the like in accordance with the coating thickness.

The step of drying the polyimine precursor resin solution applied to the metal foil is carried out at a temperature of 80 to 150 ° C, and it is preferred to appropriately set the temperature to be dried depending on the temperature. The amount of the solvent remaining after the coating and drying step is preferably 50% by mass or less based on 100% by mass of the solvent-containing resin component.

The metal clad laminate can also be produced by the following separate formation method. First, a polyimine precursor resin solution is applied onto a release film such as a PET (polyethylene terephthalate) film, a PP (polypropylene) film, or a PE (polyethylene) film to form a coating layer. Thereafter, the hardening and drying conditions (temperature: 80 to 160 ° C, time: 1 to 30 minutes) are hardened and dried to a semi-hardened state (hereinafter also referred to as B stage) to obtain a polyimide resin layer. Further, by performing a mold release treatment on the surface of the release film, the peeling property with the polyimide film layer can be improved.

Next, the resin-coated surface of the polyimide film layer was bonded to the rough surface of the metal foil to form a metal-clad laminate. As the bonding method, a pressing method, a lamination method using a hot roll, or the like can be used. The bonding conditions are preferably in the range of 200 to 350 ° C and a pressure of 0.5 to 5 MPa.

Further, although the above description has been made on the single-sided metal-clad laminate, it is also applicable to a double-sided metal-clad laminate in which metal foil is provided on both surfaces of the polyimide resin layer. The double-sided metal-clad laminate can be formed by providing a metal foil on both surfaces of the resin sheet produced by the above-described separate formation method, and then thermocompression bonding by the above-described bonding method.

The etched surface obtained by etching the metal layer of the metal clad laminate of the present embodiment into a predetermined shape is covered with a surface covering layer for metal foil circuit coating, whereby a flexible printed circuit board can be obtained. The surface coating layer is not limited as long as it can be coated with a metal foil circuit, and is, for example, a surface coating layer obtained by applying an adhesive to a film such as polyimide, a liquid resist, a dry film resist, or the like.

The strength of the polyimide film layer contained in the metal-clad laminate is preferably 100 MPa or more, more preferably 150 MPa or more.

The elongation of the polyimide film of the metal-clad laminate is preferably 20% or more, more preferably 30% or more. If the elongation of the polyimide layer is less than 20%, the elongation of the polyimide layer tends to be brittle when the elongation is too small.

The linear thermal expansion coefficient (CTE) of the polyimide film layer contained in the metal-clad laminate is preferably 22 ppm/K or less, more preferably 20 ppm/K or less. If the CTE of the polyimide film layer exceeds 22 ppm/K, the dimensional stability tends to deteriorate.

The adhesion between the polyimide film layer and the metal foil contained in the metal-clad laminate is preferably 8 N/cm or more, more preferably 10 N/cm or more. When the adhesiveness is less than 8 N/cm, peeling of the metal wiring occurs during processing, and the reliability tends to be low.

[surface coating]

The surface coating layer of the present embodiment includes a polyimide film formed of the above polyimine precursor resin solution.

The composition of the surface coating layer is not particularly limited, and an adhesive layer is usually contained in addition to the resin layer composed of the polyimide film. The adhesive layer to be contained in the surface layer is not particularly limited, and for example, one or more resins selected from the group consisting of epoxy resins, phenoxy resins, acrylic resins, and urethane resins may be contained. Further, in the adhesive layer, an additive such as a curing agent may be added depending on the type of the resin.

In the method for producing a cover layer, for example, a polyimide film, an adhesive layer, or a surface layer comprising a release film, the adhesive layer may be formed on the polyimide film and a predetermined amount of heat may be applied. The solvent component contained in the adhesive layer is evaporated. Thereafter, it was produced by laminating the release surface of the release film on the surface of the adhesive layer. At this time, the hardened state of the adhesive layer is hardened and dried as needed to be in a semi-hardened state (stage B). Further, the curing conditions can be appropriately adjusted depending on the amount of the resin of the main agent, the amount of the curing agent, and the like. Further, the adhesive layer may be provided on both sides of the polyimide film, and the release film may be appropriately removed after use.

[Flexible Printed Circuit Board]

The flexible printed circuit board of the present embodiment is obtained by providing a surface layer on a metal foil in which a metal layer of a metal clad laminate is etched into a predetermined shape and formed with a circuit. The thickness of the flexible printed circuit board of the present embodiment can be arbitrarily set depending on the application.

The flexible printed circuit board of the present embodiment can be suitably applied to, for example, a wafer package on a so-called flexible printed circuit board for IC chip packaging.

Moreover, the physical properties in the present specification can be measured by the methods described in the following examples unless otherwise specified.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited to the examples.

The diamine component, the acid anhydride component, and the solvent used in the examples and comparative examples are as follows.

(diamine component)

p-PDA: p-phenylenediamine (manufactured by Kanto Chemical Co., Ltd.)

4,4'-DAPE: 4,4'-diaminodiphenyl ether (made by Wakayama Seiki Co., Ltd.)

(anhydride component)

BPDA: 3,4,3',4'-biphenyltetracarboxylic dianhydride (Ube Industries, Ltd.)

PMDA: pyromellitic dianhydride (Daicel Chemical Industry Co., Ltd.)

TMA: trimellitic anhydride (manufactured by Kanto Chemical Co., Ltd.)

(solvent)

NMP: N-methyl-2-pyrrolidone (manufactured by Kanto Chemical Co., Ltd.)

The evaluation methods and measurement methods in the examples and comparative examples are as follows. In addition, the measurement of the strength, the elongation, and the coefficient of linear expansion (CTE) was carried out by using a copper foil obtained by removing the copper foil of the two-layer flexible copper-clad laminate obtained in the examples and the comparative examples.

(1) TMA addition amount (mole)

The difference between the molar number of the diamine component and the molar number of the tetracarboxylic dianhydride is taken as the molar number of the terminal diamine contained in the diamine-terminated polyimide precursor resin, and is used for the terminal diamine The TMA molar amount (TMA/terminal diamine) added as a molar number is taken as the TMA addition amount.

(2) Solid content concentration (% by mass)

The blending amount of the diamine component (a), the tetracarboxylic dianhydride component (b), the trimellitic anhydride component (c), and the polymerization solvent (d) when polymerizing the polyimine precursor resin is as follows Calculation.

Solid content concentration (% by mass) = [(a + b + c) / (a + b + c + d)] × 100

(3) Resin viscosity (cP)

The polymerized polyimide precursor resin solution was measured using a Viscotech digital rotary viscometer VISCOBASIC+L type at 25 ° C.

(4) Number average molecular weight (Mw), molecular weight distribution (Mw/Mn)

The polymerized polyimine precursor resin solution was dissolved in a solution of 0.01 mmol/L of lithium bromide and 0.01 mmol/L of phosphoric acid in a solution of N,N-dimethylacetamide, and GPC-made by Showa Denko Co., Ltd. was used. 104 system, calculated on the basis of polystyrene standards.

(5) Strength (MPa)

The measurement was carried out at a tensile speed of 50 mm/min in accordance with JIS K 7127 using a tensile tester (AUTOGRAPH AGS-J, manufactured by Shimadzu Corporation).

(6) Elongation (%)

The measurement was carried out at a tensile speed of 50 mm/min in accordance with JIS K 7127 using a tensile tester (AUTOGRAPH AGS-J, manufactured by Shimadzu Corporation).

(7) CTE (ppm/K)

Using a thermomechanical analyzer TMA-60 manufactured by Shimadzu Corporation, the sample size was set to a width of 5 mm and a length of 15 mm. When the load was 5 g and heated at a temperature increase rate of 10 ° C/min, the size was from 100 ° C to 200 ° C. Change seeking.

(8) Adhesion to copper foil (N/cm)

The copper foil of the two-layer flexible copper-clad laminate was formed into a sample having a pattern of a width of 3 mm, and was measured in accordance with JIS C 6471, item 8.1. The equipment was subjected to EZ-TEST manufactured by Shimadzu Corporation (stock) at a normal temperature and a test speed of 50 mm/min. The copper foil was peeled off at a 90-degree angle and the strength was measured.

(9) Storage stability

The polybendimimine precursor resin solution was stored in a 10 ° C environment for 6 months, and then measured by a Viscotech (digital) rotary viscometer VISCOBASIC + L type, and measured at 25 ° C, the viscosity change immediately after polymerization. When it is less than 1000 cP, it is rated as ○, and when it is 1000 cP or more, it is evaluated as ×.

[Example 1]

(1) Polymerization of an amine-terminated polyimide precursor resin represented by the following formula (2)'

In the formula, R ₁ represents at least one of the structures represented by the following formula (5),

R ₂ represents at least one of the structures represented by the following formula (6).

To the 500 L flask was added 240 g of NMP as a polymerization solvent. Next, 11.982 g (0.1108 mol) of p-PDA as a diamine component and 7.389 g (0.0369 mol) of 4,4'-DAPE were added, followed by stirring at 30 ° C to dissolve.

To the obtained solution, BPDA 37.543 g (0.1276 mol) and PMDA 3.097 g (0.0142 mol) as a tetracarboxylic dianhydride component were slowly added. Thereafter, the mixture was stirred at room temperature for 10 hours, whereby a solution (A) containing the amine-terminated polyimide precursor resin represented by the above formula (2)' was obtained.

(2) Production of a polythenimine precursor resin solution represented by the following formula (1)'

To 300 g of the solution (A) containing the amine-terminated polyimine precursor resin, 0.519 g (0.0027 mol) of TMA was added, and the mixture was stirred at room temperature for 3 hours, thereby obtaining a composition represented by the above formula (2)'. An amine-terminated polyimide precursor resin, a polyimine precursor resin represented by the following formula (1)', and a solution of a carboxylic acid terminal polyimine precursor resin represented by the following formula (4)' (B) ).

The same as in the formula (1) 'and (4)', R ₁ is and R ₂ of formula (2) 'R ₁ and R _2.

In the formula (1)' and the formula (4)', R ₅ represents at least one of the structures represented by the following formula (7).

In the formula (7), * represents a bonding site with a carbonyl group (C=O).

The obtained solution (B) was directly applied to a roughened surface of a copper foil (BH Y-22B-T-18 μm made of Nippon Minerals) using a bar coater, and the thickness of the resin layer after the imidization was 25 μm. It was dried at 130 ° C for 10 minutes.

The copper foil coated with the solution (B) was cooled to room temperature, and then heated to 360 ° C (temperature) at a temperature increase rate of 15 ° C / hour. Next, after maintaining at 360 ° C for 2 hours, it was naturally cooled to room temperature to obtain a two-layer flexible copper-clad laminate.

Further, the solution (B) contains the polyimine precursor resin represented by the above formula (1)', which was identified by the following FT-IR analysis.

Solution (C): Synthesis of a polyamidene precursor resin having a carboxylic acid end at both ends

To 300 g of the solution (A) containing the amine-terminated polyimide precursor resin, 1.140 g (0.0059 mol) of TMA was added, and the mixture was stirred at room temperature for 3 hours, thereby obtaining a solution (C). In the solution (C), it is considered that, similarly to the above solution (B), a polyimine precursor resin (2)' having an amine at both ends and a polyimine precursor resin each having an amine and a carboxylic acid ( 1) ', and the poly(iminemine precursor resin (4)' whose both ends are carboxylic acids. Further, the solution (C) is reacted by adding an excess of TMA to the solution (B). Therefore, it can be considered that the ratio of the polyimine precursor resin (4)' in which both ends of the solution (C) is a carboxylic acid is higher than that of the solution (B).

Production of samples for FT-IR:

The solutions (A), (B), and (C) were respectively cast on a polyethylene terephthalate (hereinafter abbreviated as PET) film, and coated by a bar coater so that the film thickness after drying became 25 μm. . Thereafter, the film was dried at 130 ° C for 10 minutes under normal pressure, and further dried at 130 ° C for 36 hours under vacuum to obtain three kinds of polyimine precursor resin films for FT-IR analysis.

Determination of FT-IR:

The obtained polyimide film of the polyimide precursor film was peeled off from the PET film, and the surface of the non-contact PET film was subjected to FT-IR-680 Plus by the Japanese spectroscopic method, and the wave number was 650 to 2000 cm ^-1 by the single-point reflection method. IR analysis.

data analysis:

The obtained IR chart is shown in Figure 1. Here, in order to confirm that the carboxylic acid group is introduced into the terminal of the polyimine precursor resin by the reaction of the amine terminal of the polyimine precursor resin with TMA, attention is paid to the vicinity of 1630 cm ^-1 of the amine group derived from the phenylamine. From the peak of the hydroxyl group of the carboxylic acid near 1410 cm ^-1 . 1100cm ^-1 to the peak intensity near the portion of the benzene ring derived from (S ₀₎ as the reference peak, and calculating the intensity of the peak portion from the vicinity of 1630cm ^{-1-aminophenyl} amine of the (S _1), from carboxymethylcellulose The ratio (S ₁ /S ₀ , S ₂ /S ₀ ) of the peak area (S ₂ ) in the vicinity of 1410 cm ^{-1 of the} acid hydroxyl group was analyzed for the behavior of the peak of each functional group source due to the presence or absence of addition of TMA. The results are shown in Table 1.

As shown in the above Table 1, it was confirmed that the ratio of the peak of the amine group derived from the phenylamine (near the vicinity of 1630 cm ^-1 ) was decreased by the addition of TMA, and the peak of the hydroxyl group of the carboxylic acid (near 1410 cm ^-1 ) was obtained. increase.

From the above, it was confirmed that by adding TMA to the amine-terminated polyimide precursor resin solution, the amine terminal reacts with TMA, and the terminal of one of them is introduced with a carboxylic acid group represented by the formula (1)' Polyimine precursor resin.

[Examples 2 to 4, Comparative Examples 1 and 2, and Reference Examples 1 to 3]

A polyimine precursor resin solution and a two-layer flexible copper-clad laminate were obtained in the same manner as in Example 1 except that the blending amounts described in Tables 1 and 2 were changed. In each of Examples, Comparative Examples and Reference Examples, the blending amounts and physical properties of the respective components are shown in Tables 2 and 3.

【Table 2】

The polyimide precursor resin solution of the present embodiment (Examples 1 to 4) has a high concentration and a low viscosity, and is also excellent in storage stability. Since the polyimine precursor resin solution of the present embodiment has a high concentration and a low viscosity, it is excellent in workability in producing a polyimide film of a polyimide film.

In addition, the polyimide film of the polyimide film obtained by curing the polyimine precursor resin solution of the present embodiment is excellent in balance of various physical properties such as strength, elongation, linear expansion coefficient, and adhesion.

The polyimine imide precursor resin solution of Comparative Example 1 in which TMA was not added was inferior in physical properties (especially elongation) of the obtained polyimide film coating film. Further, the polyamidimide precursor resin solution of Comparative Example 2 containing no TMA and containing 20% by weight of a high molecular weight polyimine had high viscosity, and was inferior in storage stability and workability.

The polyamidimide precursor resin solution of Reference Example 1 containing 15% by weight of a high molecular weight polyimine has a low solid content concentration, so that drying shrinkage at the time of production of a coating film is increased, and workability is poor.

[Industry Utilization]

The polyamidene precursor resin solution of the present invention can be utilized in the field of electronic materials, particularly in the field of flexible printed circuit boards.

Figure 1 shows an IR chart of a polyimide film of a polyimide precursor obtained in the examples.

Claims (7)

A polyamidene precursor resin solution comprising a polyamidene precursor resin represented by the following formula (1); In the formula (1), R ₁ represents a tetravalent organic group selected from any one of the structures represented by the following formula (4); and R ₂ represents any one selected from the structures represented by the following formula (5). a divalent organic group; each of R ₃ and R ₄ being the same or different and representing one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, and a phenyl group; and R ₅ represents a group selected from the group consisting of a trivalent organic group of any one of the structures represented by the formula (6); n represents an integer of 2 or more; The solution of the polyimine precursor resin in the first aspect of the invention, wherein, in the formula (1), R ₁ represents any one selected from the structures represented by the following formula (4-1); and R ₂ represents Any one of the structures represented by the following formula (5-1); R ₃ and R ₄ represent a hydrogen atom; and R ₅ represents any one selected from the structures represented by the following formula (6-1); The polyimine precursor resin solution according to claim 1 or 2, wherein the polyimine precursor resin is an amine-terminated polyimide precursor resin represented by the following formula (2) and the following formula (3) a resin obtained by reacting a tricarboxylic anhydride; In the formula (2), R ₁ to R ₄ and n are synonymous with the foregoing; In the formula (3), R ₅ is synonymous with the above. The polyamidiamine precursor resin solution of claim 3, wherein the tricarboxylic anhydride is 0.3 to 0.7 times the molar ratio relative to the terminal diamine of the amine-terminated polyimide precursor resin. reaction. A polyimide film coated with a polyimide film, as in the first to fourth aspects of the patent application Any one of the polyamidiene precursor resin solutions is obtained by hardening. A metal-clad laminate comprising a polyimide film coated on a metal foil as disclosed in claim 5 of the patent application. A flexible printed circuit board obtained by using a metal-clad laminate of the sixth aspect of the patent application.