WO2009139086A1

WO2009139086A1 - Polyester-imide precursor and polyester-imide

Info

Publication number: WO2009139086A1
Application number: PCT/JP2008/066535
Authority: WO
Inventors: 明宏加藤; 徹小泉
Original assignee: 旭化成イーマテリアルズ株式会社
Priority date: 2008-05-16
Filing date: 2008-09-12
Publication date: 2009-11-19
Also published as: TW200948862A; TWI395770B; CN102027044A

Abstract

A polyester-imide precursor characterized by having repeating units represented by the following formula (1). (In the formula (1), Ar is the tetravalent aromatic group represented by the formula (2) and B₁ is an ester structure having a specific structure.)

Description

Polyesterimide precursor and polyesterimide

The present invention relates to a polyesterimide precursor and a polyesterimide used for a laminated board such as a flexible printed wiring board.

Polyimide not only has excellent heat resistance, but also has properties such as chemical resistance, radiation resistance, electrical insulation, and excellent mechanical properties, so it is used for FPC (Flexible Printed Circuit) substrates and TAB (Tape Automated Bonding). Widely used in various electronic devices such as base materials, protective films for semiconductor elements, and interlayer insulating films for integrated circuits. In addition to these characteristics, polyimide has become increasingly important in recent years because of its simplicity of manufacturing method and extremely high film purity.

As electronic devices become lighter, thinner, and more demanding, the demands on polyimide have become stricter year by year. Not only solder heat resistance, but also the dimensional stability of polyimide film against thermal cycling and moisture absorption, transparency, and adhesion to metal substrates There has been a demand for multifunctional polyimide materials that simultaneously satisfy a plurality of characteristics such as strength, moldability, and fine workability such as through holes.

In recent years, the demand for polyimide as an FPC substrate has increased dramatically. The composition of the copper clad laminate and FCCL (Flexible Copper Clad Laminate), which are the raw materials of FPC, are mainly classified into three types. That is, 1) a three-layer type in which a polyimide layer (hereinafter also referred to as “polyimide film”) and a copper foil are attached using an epoxy adhesive, etc., 2) a polyimide solution is applied to the copper foil, and then dried or a polyimide precursor After applying the body solution, dry, imidize, or form a copper layer on the polyimide layer by vapor deposition / sputtering, etc. Non-adhesive two-layer type, 3) Pseudo two-layer type using thermoplastic polyimide as the adhesive layer, It has been known. In applications where a high degree of dimensional stability is required for the polyimide layer, a two-layer FCCL without an adhesive is advantageous.

The polyimide as the FPC board undergoes dimensional changes when exposed to various thermal cycles in the mounting process. In order to suppress this as much as possible, in addition to the glass transition temperature (Tg) of the polyimide being higher than the process temperature, the coefficient of linear thermal expansion below the glass transition temperature is as low as possible, matching the coefficient of linear thermal expansion of the metal foil. It is desirable that As will be described later, the control of the linear thermal expansion coefficient of the polyimide layer is important from the viewpoint of reducing the residual stress generated during the two-layer FCCL manufacturing process. In addition, for FPC boards, development of highly flame-retardant polyimide is desired from the viewpoint of safety.

Many polyimides are insoluble in organic solvents and do not melt above the glass transition temperature, so it is usually not easy to mold the polyimide itself. Therefore, polyimide generally includes an aromatic tetracarboxylic dianhydride such as pyromellitic anhydride (PMDA) and an aromatic diamine such as 4,4′-oxydianiline (ODA), and dimethylacetamide (DMAc). First, a polyimide precursor solution having a high degree of polymerization is polymerized in an aprotic polar organic solvent to polymerize the polyimide precursor solution, and this polyimide precursor solution is applied onto a metal foil, for example, a copper foil. The film is formed by heating and dehydration ring closure (imidization).

Residual stress is generated in the process of cooling the metal / polyimide laminate to room temperature after the imidization reaction at a high temperature, and serious problems such as FCCL curling, peeling, and film cracking often occur. Even when the polyimide solution is used, the problem of residual stress occurs in the drying-cooling process, as in the case of using the polyimide precursor solution.

As a measure for reducing the residual stress, it is effective to reduce the coefficient of linear thermal expansion of the polyimide itself, which is an insulating film. Most polyimides have a linear thermal expansion coefficient in the range of 40 ppm / ° C. to 100 ppm / ° C., which is much larger than that of metal foil, for example, copper foil, 17 ppm / ° C. The research and development of polyimide, which exhibits a coefficient of linear thermal expansion of about 20 ppm / ° C. or less, has been conducted.

Currently, a polyimide formed from 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine is well known as a practical polyimide material. Although this polyimide film shows a very low linear thermal expansion coefficient of 5 ppm / ° C. to 10 ppm / ° C., depending on the film thickness and production conditions, it does not show a low hygroscopic expansion coefficient (see Non-Patent Document 1).

Dimensional stability of polyimide is required not only for thermal cycling but also for moisture absorption. Conventional polyimide absorbs 2 to 3% by mass of water. Circuit misalignment due to dimensional changes due to moisture absorption of the insulating layer is a serious problem for high-density wiring and multilayer wiring. A serious problem may be caused by deterioration of electrical characteristics such as corrosion at the polyimide / conductor interface, ion migration, and dielectric breakdown. Therefore, the polyimide layer as the insulating film is required to have a hygroscopic expansion coefficient as low as possible.

In order to realize a low hygroscopic expansion coefficient, for example, it has been reported that a polyesterimide using an acid dianhydride having an ester structure in the skeleton represented by the formula (20) is effective (see Patent Document 1).

However, the polyesterimide film produced using the general formula (20) as the acid dianhydride and the formulas (21) to (23) as the diamine in order to realize a low hygroscopic expansion coefficient, the diamine has a highly flexible structure. Therefore, it is considered that not only a high linear thermal expansion coefficient but also a polyesterimide film made of a combination thereof becomes a combustible film.

Here, when a diamine having a rigid structure such as formula (24) is used as the diamine, the coefficient of thermal expansion is low, but because of its rigidity, it has a high elastic modulus, which is not preferable in applications where low resilience is required. Further, it is presumed that the adhesion (peeling strength with the metal foil) is further lowered.

Therefore, a polyesterimide using an acid dianhydride (hereinafter referred to as TABP) represented by the formula (19) has also been reported (see Patent Document 2).

There is a description that the polyesterimide obtained from the diamine and the acid dianhydride disclosed in Patent Document 2 achieves a low thermal expansion coefficient and a low water absorption (1.2% to 1.9%) at the same time. . However, it is considered difficult for a polyesterimide film having a water absorption rate of 1.2% to satisfy a low hygroscopic expansion coefficient (8 ppm /% RH or less, 30% RH-70% RH). Moreover, in the processing process of the FPC board which consists of a thin film polyimide film, in order to avoid the fall of the yield by a polyimide film tear, it is calculated | required that a polyimide film is high tear strength, The said literature is about tear strength. Is not disclosed. Also, it is believed that high tear strength cannot be achieved with the described polyesterimide composition. Moreover, since the flexible molecule | numerator like Formula (21) and Formula (25) is used, it is thought that a glass transition temperature is also low.

On the other hand, a polyesterimide using a compound having an ester structure as a diamine has also been reported (see Patent Document 3). However, in this case as well, it is considered that high tear strength cannot be obtained in the same manner as described above.

In addition, there is a possibility that problems may occur due to the use of TABP. A general method for producing an acid dianhydride having an ester structure is a method of reacting trimellitic anhydride chloride with a diol in benzene or toluene (Patent Document 4), or a lower alkanoic acid ester of phenol and anhydrous. A transesterification reaction with trimellitic acid (Patent Document 5) is known, and a TABP crude crystal can be obtained by these methods. However, when the obtained crude crystals are used for copolymerization with an aromatic diamine, the resulting polyimide precursor solution partially gels, and when a polyimide film is produced using the polyimide precursor solution, polyimide is obtained. There is a possibility that the mechanical properties of the film are significantly deteriorated.

Thus, while maintaining the polymerization reactivity and film forming processability, it has the same low linear thermal expansion coefficient, high flame retardancy, and low hygroscopic expansion coefficient (8 ppm /% RH or less, 30% RH-70% RH) as copper foil. In addition to flexibility, solder heat resistance, high glass transition temperature, high adhesion, and low elastic modulus, it is not easy in terms of molecular design to obtain a polyimide that achieves high tear strength. At present, no satisfactory practical materials are known.
Japanese Patent Laid-Open No. 10-70157 JP 2006-336011 A Japanese Patent No. 3712164 Japanese Patent Publication No. 43-5911 JP 07-41472 A Macromolecules, 29, 7897 (1996).

The present invention has been made in view of such points, and has high flame retardancy, low hygroscopic expansion coefficient, low linear thermal expansion coefficient equivalent to copper foil, high glass transition temperature, high adhesion, low elastic modulus, and high tear strength. It aims at providing the polyesterimide which has both.

The polyesterimide precursor of the present invention has a repeating unit represented by the following formula (1).

(In the formula (1), Ar is a tetravalent aromatic group represented by the formula (2), and B ₁ is a divalent fragrance selected from at least one of the formulas (3) to (9). R ₁ represents an alkyl group having 1 to 6 carbon atoms, R ₂ to R ₄ represent an alkyl group having 1 to 6 carbon atoms and a hydrogen atom, which are independent of each other, and may be the same or different R ₅ represents an alkyl group having 1 to 6 carbon atoms, and R ₆ to R ₉ represent an alkyl group having 1 to 6 carbon atoms and a hydrogen atom.)

In the polyesterimide precursor of the present invention, in the polyesterimide precursor, B ₁ in the formula (1) is preferably a repeating unit represented by the formula (3) or the formula (4). 4) is more preferable, and in Formula (4), R ₂ to R ₄ are particularly preferably Formula (10) in which a hydrogen atom is selected.

The polyesterimide precursor of the present invention has repeating units represented by the following formula (11) and formula (12), and the molar ratio of formula (11) and formula (12) is formula (11) / formula (12 ) = 20/80 to 80/20.

(In the formula (11) and the formula (12), Ar is a tetravalent aromatic group represented by the formula (2). In the formula (12), B ₂ is represented by the formulas (13) to (17). Is a divalent aromatic group selected from at least one, and R ₁₀ to R ₁₈ each represents an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and each is independent and may be the same or different Good.)

In the polyesterimide precursor of the present invention, B ₂ in the formula (12) in the polyesterimide precursor is a repeating unit represented by the formula (16), the formula (17), or the formula (18). Preferably, Formula (16) is more preferable.

In the polyesterimide precursor of the present invention, the weight average molecular weight Mw is preferably 30,000 to 400,000.

In the polyesterimide precursor of the present invention, the ester group-containing tetracarboxylic dianhydride represented by the formula (19) used for obtaining the polyesterimide precursor is melted by a differential scanning calorimeter (DSC). Thermal peak temperature (a) ° C, temperature at the intersection of tangents with the temperature at which the rise to the melting heat peak starts and the temperature at which the peak slope settles constant is (b) ° C, and the temperature range ΔT = ((b) -(A)) When it is set to ° C, (a) ≥ 322 ° C and ΔT ≤ 5 ° C are satisfied.

The polyesterimide of the present invention is obtained by imidizing the above polyesterimide precursor.

The method for producing a polyesterimide according to the present invention is characterized in that the polyesterimide precursor is heated or imidized using a dehydrating reagent to obtain a polyesterimide.

The laminate of the present invention has a polyesterimide layer and a metal layer, and the polyesterimide layer is composed of the polyesterimide.

The laminate of the present invention is obtained by applying the polyesterimide precursor on a metal foil, drying, and imidizing with heating or a dehydrating reagent.

The flexible printed wiring board of the present invention is characterized in that the metal layer of the laminated board is patterned into wiring.

The polyesterimide obtained from the polyesterimide precursor according to the present invention has high flame retardancy, low hygroscopic expansion coefficient, low linear thermal expansion coefficient equivalent to copper foil, high glass transition temperature, high adhesion, low elastic modulus, high tearing. It has the effect of having strength.

It is a figure which shows the profile shown with a differential scanning calorimeter.

As a molecular design for low linear thermal expansion of polyimide, it is necessary to make the main chain skeleton as straight and rigid as possible (various conformations are difficult to take due to internal rotation). However, on the other hand, this reduces the entanglement of the polymer chains and may cause the film to become brittle. In addition, excessive introduction of a flexible unit such as an ether structure into the polyimide skeleton greatly contributes to improvement in film toughness and adhesion strength with metal foil, but it hinders the expression of low linear thermal expansion characteristics. is expected.

The ester structure focused on in the present invention has a higher internal rotation barrier than the ether structure, and the change in conformation is relatively hindered. Therefore, the ester structure behaves as a rigid structural unit and imparts some flexibility to the polyimide main chain. It is expected to give a flexible film.

Also, since the ester structure has a lower polarizability than the amide structure or imide structure, the introduction of the ester structure into the polyimide is advantageous for reducing the hygroscopic expansion coefficient.

In the present invention, a monomer having a specific aromatic skeleton and an ester structure is selected as the acid dianhydride and diamine, and the specific aromatic skeleton and the ester structure are introduced into the polyimide. A polyesterimide precursor having a repeating unit can be obtained. Thereby, the polyesterimide precursor according to the present invention has high flame retardancy, low hygroscopic expansion coefficient, low linear thermal expansion coefficient equivalent to copper foil, high glass transition temperature, high adhesion, low elastic modulus, and high tear strength. Realized at the same time.

In the formula (1), Ar is a tetravalent aromatic group represented by the formula (2), and B ₁ is a divalent aromatic group selected from at least one of the formulas (3) to (9) It is a group. R ₁ represents an alkyl group having 1 to 6 carbon atoms. R ₂ to R ₄ each represent an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and are independent and may be the same or different. R ₅ represents an alkyl group having 1 to 6 carbon atoms. R ₆ to R ₉ each represents an alkyl group having 1 to 6 carbon atoms or a hydrogen atom.

The polyesterimide precursor according to the present invention is produced by using an ester group-containing tetracarboxylic dianhydride monomer and an ester group-containing diamine monomer. Depending on the reaction position of the diamine and acid dianhydride, four types of isomers can be considered. Since the same product is obtained from the four types of isomers after imidation, the resulting polyesterimide precursor is represented by the general formula (1 ).

When polymerizing the polyesterimide precursor of the present invention, a tetracarboxylic dianhydride (hereinafter referred to as TABP) having an ester structure represented by the formula (19) is used as an essential component as a monomer having an ester group. ) To at least one of diamines selected from the formula (33) is used. R ₁ represents an alkyl group having 1 to 6 carbon atoms. R ₂ to R ₄ each represent an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and are independent and may be the same or different. R ₅ represents an alkyl group having 1 to 6 carbon atoms. R ₆ to R ₉ each represents an alkyl group having 1 to 6 carbon atoms or a hydrogen atom. Here, from the viewpoint of low elastic modulus and adhesiveness, Formula (26) and Formula (27) are preferable, Formula (27) is more preferable, and Formula (33) is particularly preferable.

Furthermore, from the viewpoint of the warp of the laminated board after curing and the tear strength of the resulting polyesterimide film, when polymerizing the polyesterimide precursor of the present invention, a diamine having an ester structure represented by TABP and formula (33) ( Hereinafter, it is preferable to use BPIP) as an essential component and to use at least one diamine selected from the formulas (34) to (39). Moreover, Formula (37), Formula (38), and Formula (39) are more preferable, and Formula (37) is particularly preferable from the viewpoint of the tear strength of the resulting polyesterimide film. Here, R ₁₀ to R ₁₈ represent an alkyl group having 1 to 6 carbon atoms and a hydrogen atom, and are independent and may be the same or different.

In general, it is known that a polyesterimide film having a linear thermal expansion coefficient equivalent to that of copper foil is less warped after curing. The knowledge that it cannot be determined has been obtained, and the one having a linear thermal expansion coefficient equivalent to that of the copper foil and less warping is more preferable in the processing step of the FPC board.

Here, in order to obtain a molar ratio of the general formula (11) / general formula (12) = 20/80 to 80/20, TABP and the total diamine are mixed at a ratio of about 1: 1, Is 100 mol%, BPIP is used in a diamine molar ratio of 20 mol% to 80 mol%, and at least one diamine having an ester structure selected from the general formula (34) to the general formula (39) is used as the diamine molar ratio. Used at 20 mol% to 80 mol%.

Here, from the viewpoint of the linear thermal expansion coefficient, the warp of the laminated plate after curing, and the tear strength of the obtained film, the molar ratio is represented by the general formula (11) / general formula (12) = 20/80 to 80/20. A ratio is preferable, and a ratio of the general formula (11) / general formula (12) = 30/70 to 70/30 is more preferable.

Further, TABP used as an essential component is preferably highly pure from the viewpoint of making a high molecular weight polyimide precursor solution having no gel component, adhesive strength of the metal / polyimide laminate, and tear strength of the polyimide film. . Specifically, in the profile of FIG. 1 shown by the differential scanning calorimeter, the melting heat peak temperature is (a) ° C., the virtual tangent line with the temperature at which the rise to the melting heat peak starts and the melting point When the temperature at which the thermal peak intersects with the straight line along the substantially straight line portion is (b) ° C. and the temperature range ΔT = ((b) − (a)) ° C., (a) ≧ 322 ° C. and ΔT ≦ A TABP satisfying 5 ° C. is preferred, and a TABP satisfying (a) ≧ 325 ° C. and ΔT ≦ 4 ° C. is more preferred.

The present inventor has focused on the process of purifying TABP in order to make TABP highly pure, and has found the following. That is, by recrystallization in a specific solvent, concentration, and temperature conditions, the 4,4′-biphenol derivative represented by the formula (40) mixed together and the 4,4′-form represented by the formula (41) are mixed. Oligomer bodies estimated to be obtained by ring-opening and reaction of biphenol and trimellitic anhydride chloride are efficiently removed, and then subjected to dehydration heat drying treatment, thereby adhering water adhering to the crystals and It was found that the water of crystallization was removed, and the tetracarboxylic acid that was partially opened during recrystallization was dehydrated to obtain high-purity TABP.

(Where n is 1 to 5)

With TABP, as the purity increases, the temperature of the heat of fusion peak indicated by the differential scanning calorimeter (DSC) shifts to the high temperature side, and the temperature of the heat of fusion peak is (a) ° C. The temperature difference between (a) and (b) when the temperature at the intersection of the virtual tangent with the temperature at which the start of the rise starts as a contact and the straight line along the substantially straight line portion of the melting heat peak is (b) ° C. Becomes smaller.

TABP uses a reaction product obtained by reaction between trimellitic anhydride chloride and diol in an organic solvent, or transesterification of a lower alkanoic acid ester of phenol with trimellitic acid or its anhydride in a specific solvent, concentration. It is obtained by recrystallization under temperature conditions, followed by dehydration heat drying treatment.

The solvent used for recrystallization to obtain high-purity TABP is preferably a lactone solvent having a cyclic ester structure, a solvent having a cyclic ketone structure, a cyclic carbonate structure, or a cyclic sulfone structure. Examples include α-methylene-γ-valerolactone, α-methylene-γ-butyrolactone, γ-methylene-γ-butyrolactone, γ-valerolactone, γ-butyrolactone, cyclopentanone, propylene carbonate, ethylene carbonate, sulfolane. It is done. These can be used alone or in admixture of two or more. Of these, γ-butyrolactone, γ-valerolactone, and sulfolane are preferably used from the viewpoints of solubility, recrystallization yield, and economic efficiency.

The amount of the solvent used is 1 to 150 parts by weight, particularly 4 to 100 parts by weight, based on 1 part by weight of the product obtained by the reaction, considering the removal of impurities and the recrystallization yield. It is preferable that When the concentration of the ester group-containing tetracarboxylic dianhydride in the solution of the ester group-containing tetracarboxylic dianhydride and the solvent is defined as the solid content concentration, the solid content concentration is preferably 50% or less. From the viewpoint of rate, it is preferably 20% or less.

At the time of recrystallization, it is mixed with a predetermined amount of solvent so as to have the above-mentioned concentration, heated to 150 ° C. to 300 ° C., and completely dissolved. Thereafter, the precipitate obtained by allowing the system to stand at room temperature is filtered off. By this step, the 4,4′-biphenol derivative represented by the formula (40) generated during the reaction or the 4,4′-biphenol represented by the formula (41) and trimellitic anhydride chloride are opened to react. Oligomer bodies estimated to be obtained in this manner are efficiently removed by remaining in the filtrate.

(Where n is 1 to 5)

The precipitate obtained by filtration is heated at a rate of temperature increase of 1 ° C./min to 20 ° C./min, 200 ° C. to 300 ° C. under an inert atmosphere such as nitrogen, helium, argon, etc. in atmospheric pressure or under reduced pressure. By carrying out the dehydration heat treatment at a temperature of 3 ° C. for 3 hours or more, the adhering water adhering to the crystal and the water of crystallization are removed, and the tetracarboxylic acid that has been ring-opened at the time of recrystallization is dehydrated. In order to efficiently remove the adhering water and water of crystallization adhering to the crystal, it is held at a temperature of 100 ° C. to 130 ° C. for 30 minutes to 1 hour, and then at a temperature of 200 ° C. to 300 ° C. for 3 hours. It is more preferable to carry out dehydration heating (dehydration ring closure reaction) as described above. Further, the rate of temperature rise is preferably 20 ° C./min or less from the viewpoint that the heating of the crystal is made uniform and the crystal is locally heated to avoid a decomposition reaction such as decarboxylation.

The melting heat peak temperature (a) ° C. indicated by the differential scanning calorimeter (DSC) is the melting point (mp) of the substance, shifts to a higher temperature side than 322 ° C., preferably 325 ° C., and rises to the melting heat peak. The temperature difference between (a) and (b) is 5 ° C., where (b) ° C. is the temperature at which the hypothetical tangent line with the temperature starting from the point of contact as the contact point and the straight line along the substantially straight line portion of the melting heat peak Preferably it becomes narrower than 4 degreeC, and there exists a correlation with the improvement of the purity of TABP. By satisfying these conditions, it is possible to polymerize a polyesterimide precursor having a high molecular weight and no gel component.

Also, it is possible to produce a polyimide having the above characteristics at a low cost without using an expensive monomer such as a fluorinated monomer (a monomer containing a fluorine atom) in order to obtain a low hygroscopic expansion coefficient.

Embodiments of the present invention will be described in detail below, but these are examples of the embodiments of the present invention and are not limited to these contents.

In the present invention, in addition to the structural characteristics such as rigidity and hydrophobicity of a monomer having an ester structure and a specific aromatic structure, an appropriate flexibility is blended in a balanced manner. High flame retardancy, low hygroscopic expansion coefficient, low linear thermal expansion coefficient equivalent to copper foil, high glass transition temperature, flexibility, high adhesion, low elastic modulus when used as an imide laminate and polyesterimide film In addition, it is possible to obtain a material having physical properties that cannot be obtained by a conventional material and has both high tear strength.

<Method for producing polyesterimide precursor>
The method for producing the polyesterimide precursor according to the present invention is not particularly limited, and a known method can be applied. More specifically, it is obtained by the following method.

First, a diamine is dissolved in a reaction solvent, tetracarboxylic dianhydride powder is gradually added thereto, and a mechanical stirrer is used at 0 ° C. to 100 ° C., preferably 20 ° C. to 90 ° C., for 0.5 hour to 100 hours. Preferably, stirring is performed for 1 hour to 24 hours. At this time, the monomer concentration is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 40% by mass, and particularly preferably 10% by mass to 40% by mass from the viewpoint of the degree of polymerization and the solubility of the monomer and the polymer to be formed. 25 mass% is preferable. By carrying out polymerization in this monomer concentration range, a polyesterimide precursor solution having a uniform and high degree of polymerization can be obtained. Here, the obtained polyesterimide precursor solution is the same as the polyesterimide precursor described in the claims.

The weight average molecular weight (Mw) of the polyesterimide film is preferably 30,000 to 400,000, more preferably 30,000 to 300,000. Particularly preferred is 50,000 to 200,000. Here, from the viewpoint of toughness, 30,000 or more is preferable, and 50,000 or more is more preferable. Further, from the viewpoint of adhesiveness and coating property, the weight average molecular weight (Mw) is preferably 400,000 or less, more preferably 300,000 or less, and particularly preferably 200,000 or less.

Aromatic tetracarboxylic dianhydrides that can be used in combination with TABP within the range that does not impair the required characteristics of the polyesterimide film and the polymerization reactivity of the polyesterimide precursor include 3,3 ′, 4,4′-biphenyltetracarboxylic acid. Acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′ , 4,4'-biphenyl ether tetracarboxylic dianhydride, p-phenylenebis (trimellitic acid monoester acid anhydride), p-methylphenylenebis (trimellitic acid monoester acid anhydride), 3,3 ' , 4,4′-biphenylsulfonetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropa Acid dianhydride, 2,2'-bis (3,4-carboxyphenyl) propanoic acid dianhydride, and the like 1,4,5,8-naphthalene tetracarboxylic dianhydride. Two or more of these may be used in combination.

The aliphatic tetracarboxylic dianhydride that can be used in combination with TABP is not particularly limited as long as the required properties of the polyesterimide film and the polymerization reactivity of the polyesterimide precursor are not impaired, but bicyclo [2.2.2]. Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5- (dioxotetrahydrofuryl-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 4- (2 , 5-Dioxotetrahydrofuran-3-yl) -tetralin-1,2-dicarboxylic anhydride, tetrahydrofuran-2,3,4,5-tetracarboxylic dianhydride, bicyclo-3,3 ′, 4,4 '-Tetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid Such anhydrides. It is also possible to use two or more of these.

Fragrance that can be used in combination with a diamine having an ester structure represented by the general formula (26) to the general formula (39) as long as the polymerization reactivity of the polyesterimide precursor according to the present invention and the required properties of the polyesterimide are not significantly impaired. The group diamine is not particularly limited, but p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, 2,4-diaminodurene, 4,4 '-Diaminodiphenylmethane, 4,4'-methylenebis (2-methylaniline), 4,4'-methylenebis (2-ethylaniline), 4,4'-methylenebis (2,6-dimethylaniline), 4,4' -Methylenebis (2,6-diethylaniline), 4,4'-diaminodiphenyl ether, 3,4'-diamy Diphenyl ether, 3,3'-diaminodiphenyl ether, 2,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 3,3'-diamino Benzophenone, 4,4′-diaminobenzanilide, benzidine, 3,3′-dihydroxybenzidine, 3,3′-dimethoxybenzidine, o-tolidine, m-tolidine, 2,2′-bis (trifluoromethyl) benzidine, 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- (3-aminophenoxy) phenyl) sulfur , Bis (4- (4-aminophenoxy) phenyl) sulfone, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-aminophenoxy) phenyl) Examples include hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, and p-terphenylenediamine. Two or more of these may be used in combination.

Fat that can be used in combination with a diamine having an ester structure represented by the general formula (26) to the general formula (39) as long as the polymerization reactivity of the polyesterimide precursor according to the present invention and the required properties of the polyesterimide are not significantly impaired. The group diamine is not particularly limited. For example, 4,4′-methylenebis (cyclohexylamine), isophoronediamine, trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, 1,4-cyclohexanebis ( Methylamine), 2,5-bis (aminomethyl) bicyclo [2.2.1] heptane, 2,6-bis (aminomethyl) bicyclo [2.2.1] heptane, 3,8-bis (aminomethyl) ) Tricyclo [5.2.1.0] decane, 1,3-diaminoadamantane, 2,2-bis (4-amino) Cyclohexyl) propane, 2,2-bis (4-aminocyclohexyl) hexafluoropropane, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, Examples include 1,7-heptamethylenediamine, 1,8-octamethylenediamine, and 1,9-nonamethylenediamine. Two or more of these may be used in combination.

The solvent used in the polymerization reaction is not a problem as long as the raw material monomer and the generated polyesterimide precursor are dissolved, and the structure is not particularly limited. Specifically, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone; γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, Cyclic ester solvents such as ε-caprolactone and α-methyl-γ-butyrolactone; carbonate solvents such as ethylene carbonate and propylene carbonate; glycol solvents such as triethylene glycol; m-cresol, p-cresol, 3-chlorophenol And phenol solvents such as 4-chlorophenol; acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like. From the viewpoint of solubility, aprotic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone are used. preferable.

Other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol monomethyl ether acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, Tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, petroleum naphtha solvents, etc. Can also be used.

The polyesterimide precursor according to the present invention can be isolated as a powder by dropping, filtering and drying the solution in a large amount of poor solvent such as water or methanol.

<Method for producing polyesterimide>
The polyesterimide according to the present invention can be produced by subjecting the polyesterimide precursor obtained by the above method to a dehydration ring-closing reaction (imidation reaction). At this time, usable forms of polyesterimide are a film, a metal foil / polyesterimide laminate, a powder, a molded product, and a solution.

The polyesterimide precursor solution is cast on a metal foil such as a copper foil or an aluminum foil and dried in an oven at 40 ° C. to 180 ° C., preferably 50 ° C. to 150 ° C. The obtained metal / polyesterimide precursor laminate was fixed to a SUS metal plate with a tape and fixed in a vacuum, in an inert gas such as nitrogen, or in air, 200 ° C. to 430 ° C., preferably 250 ° C. A metal / polyimide laminate is obtained by heating at ˜400 ° C. The polyesterimide film according to the present invention can be produced by etching and removing the metal layer of the laminate. There is also a method of obtaining a polyesterimide film using a silicon substrate on which a metal is deposited. In this case, the polyesterimide precursor solution is cast on a silicon substrate on which a metal layer is deposited, dried and heated by the above method, and a silicon / polyesterimide layer laminate on which the metal layer is deposited is obtained. . Thereafter, the metal layer of the laminate is etched and the polyesterimide layer (polyesterimide film) is peeled off from the silicon substrate, whereby the target product can be obtained.

There is also a method for obtaining a polyesterimide film using a glass substrate. The polyesterimide precursor solution is cast on a glass substrate and dried in an oven at 40 ° C. to 180 ° C., preferably 50 ° C. to 150 ° C., to obtain a laminate of a glass substrate / polyesterimide precursor layer. Thereafter, the polyesterimide precursor layer (polyesterimide precursor film) is peeled off from the laminate, the polyesterimide precursor film is fixed to a metal frame using a tape, and heated by the method described above. Can be obtained.

From the viewpoint of the ring-closing reaction of imidization, 200 ° C. or higher is preferable, and from the viewpoint of thermal stability of the produced polyesterimide film, 430 ° C. or lower is preferable. The imidization is desirably performed in a vacuum or in an inert gas, but may be performed in air if the imidization temperature is not too high.

In addition, the imidization reaction is carried out by adding a tertiary amine such as pyridine or triethylamine to the polyesterimide precursor solution instead of heat treatment to prepare a polyesterimide precursor film, and heating the chemical imide while heating at 200 ° C to 300 ° C. It is also possible to carry out by immersing the polyesterimide precursor film in a solution containing a dehydrating reagent such as acetic anhydride in the presence of a tertiary amine such as pyridine or triethylamine.

Here, although the manufacturing method of the polyesterimide film from the polyesterimide precursor solution was described, it is not limited to this, The heat-dried polyesterimide precursor film and the isolated polyesterimide precursor are heated, Alternatively, a polyesterimide may be produced by cyclization using a dehydrating reagent. When the polyesterimide is insoluble in a solvent, a crystalline polyesterimide powder can be obtained as a precipitate. A polyesterimide molded body can be produced by heating and compressing the polyesterimide powder at 200 ° C. to 450 ° C., preferably 250 ° C. to 430 ° C.

Further, by adding and stirring a dehydrating reagent such as N, N′-dicyclohexylcarbodiimide or trifluoroacetic anhydride to the polyesterimide precursor solution, the mixture is reacted at 0 ° C. to 100 ° C., preferably 0 ° C. to 60 ° C. Polyisoimide, which is an isomer of polyesterimide, is produced. The polyisoimide solution can be easily converted into a polyesterimide by heat-treating at 250 ° C. to 450 ° C., preferably 270 ° C. to 400 ° C., after forming a film by the same procedure as described above. The isoimidization reaction can also be performed by immersing the polyesterimide precursor film in a solution containing the dehydrating reagent.

When the polyesterimide is dissolved in a solvent, the polyesterimide solution can be easily produced by heating the polyesterimide precursor solution as it is or after appropriately diluting with the same solvent to 150 ° C. to 200 ° C. At this time, toluene, xylene, or the like may be added in order to azeotropically distill off water which is a by-product of imidization. A base such as γ-picoline can be added as a catalyst.

It is also possible to isolate the polyesterimide as a powder by dropping and filtering the obtained polyesterimide solution in a large amount of poor solvent such as water or methanol. Further, the polyesterimide powder can be redissolved in the above solvent to obtain a polyesterimide solution.

The polyesterimide of the present invention can be obtained by imidizing the polyesterimide precursor of the present invention. Usually, the molecular weight and terminal structure of the produced polyesterimide can be adjusted by adjusting the ratio of the tetracarboxylic dianhydride and the diamine compound used in the production. The preferred molar ratio of total tetracarboxylic dianhydride to total diamine is 0.90 to 1.10.

The terminal structure of the resulting polyesterimide is an amine or acid anhydride structure depending on the molar charge ratio of all tetracarboxylic dianhydrides and all diamines at the time of production. When the terminal structure is an amine, the terminal structure may be capped with a carboxylic acid anhydride. Examples of these include phthalic anhydride, 4-phenylphthalic anhydride, 4-phenoxyphthalic anhydride, 4-phenylcarbonylphthalic anhydride, 4-phenylsulfonylphthalic anhydride, etc. It is not limited to. You may use these carboxylic anhydrides individually or in mixture of 2 or more types.

Further, when the terminal structure is an acid anhydride, the terminal structure may be capped with a monoamine. Specific examples include aniline, toluidine, aminophenol, aminobiphenyl, aminobenzophenone, naphthylamine and the like. You may use these monoamines individually or in mixture of 2 or more types.

The addition polymerization conditions can be carried out in accordance with the conventional polyamic acid addition polymerization conditions. Specifically, first, an aromatic diamine is dissolved in a solvent at 0 ° C. to 80 ° C. under an inert atmosphere such as nitrogen, helium, argon, etc., and then tetracarboxylic acid at 40 ° C. to 100 ° C. The dianhydride is allowed to undergo addition polymerization for 4 to 8 hours while being quickly added. Thereby, a polyesterimide precursor is obtained.

A polyesterimide film can also be formed by applying the above polyesterimide solution on a substrate and drying at 40 ° C to 400 ° C, preferably 100 ° C to 300 ° C.

A polyester imide precursor solution is applied onto a metal foil, for example, a copper foil, dried, and then imidized under the above-described conditions, whereby a metal plate and a polyester imide layer laminate (FCCL) which is an original fabric of an FPC board are obtained. Obtainable. Here, a copper foil is used as the metal foil, and a non-adhesive two-layer type composed of a copper foil and a polyesterimide layer can be obtained by directly applying a polyesterimide precursor solution. On the other hand, a three-layer and pseudo two-layer type in which a polyesterimide layer and a copper foil are bonded using an epoxy adhesive or a thermoplastic polyimide as an adhesive are also generally known as FCCL configurations. In this case, since it is essential for the adhesive to be thermoplastic, it is essential to contain a bending component in the constituent unit of the adhesive, and the high hygroscopic expansion coefficient, glass transition temperature, and heat resistance are lowered. For this reason, in a three-layer or pseudo-two-layer type laminate, a high hygroscopic expansion coefficient, a low glass transition temperature, and a low heat resistance are inevitably caused by the thermoplastic adhesive layer. On the other hand, since the polyesterimide of the present invention has high adhesiveness, it is possible to obtain a two-layer laminate without using an adhesive layer, and the polyesterimide itself is also non-thermoplastic. Therefore, it is possible to simultaneously have high glass transition temperature heat resistance and low hygroscopic expansion coefficient.

As the metal foil of the FPC board, various metal foils can be used, but aluminum foil, copper foil, and stainless steel foil are preferable, and copper foil is particularly preferable. These metal foils may be subjected to surface treatment such as mat treatment, plating treatment, chromate treatment, aluminum alcoholate treatment, aluminum chelate treatment, silane coupling agent treatment, and the like.

The thickness of the metal foil is not particularly limited, but is preferably 35 μm or less, more preferably 18 μm or less.

FCCL can be manufactured as follows, for example.
First, the polyesterimide precursor solution is coated on a metal foil using a blade coater, a lip coater, a gravure coater or the like. Then, it is dried to form a polyesterimide precursor layer (hereinafter also referred to as “polyesterimide precursor film”). The coating thickness is affected by the solid content concentration of the polyesterimide precursor solution, but the polyesterimide precursor layer is heated at 200 ° C. to 400 ° C. in an inert atmosphere such as nitrogen, helium, or argon. A polyesterimide layer can be formed by making it. The thickness of the polyesterimide layer is 100 μm or less, preferably 50 μm or less, more preferably 30 μm or less.

Here, the peel strength from the metal foil is preferably 0.8 N / mm or more, and more preferably 1.0 N / mm or more. Warpage is preferably 10 mm or less, and more preferably 3 mm or less.

By using the above FCCL as an etching solution using ferric chloride aqueous solution (manufactured by Tsurumi Soda Co., Ltd., 40 Baume, ferric chloride 37% or more) at room temperature or under 50 ° C. heating condition, By etching the metal layer into a desired circuit shape, an adhesive-free flexible printed wiring board can be manufactured.

Here, the tear strength of the polyimide film is preferably 50 mN or more, more preferably 60 mN or more, and particularly preferably 80 mN or more in the polyimide film 26 μm. The elastic modulus is preferably 4.0 GPa to 6.5 GPa. The hygroscopic expansion coefficient is preferably 7 ppm /% RH or less, the linear thermal expansion coefficient is preferably 16 ppm / ° C. to 25 ppm / ° C., and the glass transition temperature is preferably 350 ° C. or higher.

Add additives such as an oxidation stabilizer, a filler, an adhesion promoter, a silane coupling agent, a photosensitizer, a photopolymerization initiator, and a sensitizer to the polyesterimide of the present invention and its precursor solution as necessary. Can do.

The polyesterimide of the present invention has high flame retardancy, low hygroscopic expansion coefficient, low linear thermal expansion coefficient equivalent to copper foil, high glass transition temperature, high adhesive strength, low elastic modulus, and high tear strength. It can be used for an electrical insulating film, a flexible printed wiring board, a display substrate, an electronic paper substrate, a solar cell substrate, etc. in a device, and is particularly useful as a substrate for a flexible printed wiring board.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, the physical-property value in the following examples was measured by the method shown below.

<Polyesterimide precursor solution>
First, a diamine containing an ester structure is dissolved in N-methyl-2-pyrrolidone, and tetracarboxylic dianhydride powder containing an ester structure is gradually added thereto, and then heated at 80 ° C. using a mechanical stirrer. For 3 to 5 hours. At this time, polymerization was performed in a monomer concentration range of 10% by mass to 20% by mass of the monomer to obtain a polyesterimide precursor solution having a uniform and high polymerization degree.

<Copper foil / polyesterimide laminate>
A 12 μm-thick copper foil (NIPPON ELECTRIC CO., LTD. USLP foil) was placed on a metal coating table so that the matte surface was the surface. The surface temperature of the coating table was set to 90 ° C., and the polyesterimide precursor solution obtained above was applied to the copper foil mat surface with a doctor blade. Then, after leaving still for 30 minutes on a coating table, and further leaving still in a dryer at 100 ° C. for 30 minutes, a copper foil / polyesterimide precursor laminate without tackiness (polyesterimide precursor layer thickness 47 μm and 24 μm) was obtained. Next, a copper foil / polyesterimide precursor laminate was fixed on a SUS metal plate with a tape and fixed at 30 ° C. at 150 ° C. at a temperature rising rate of 5 ° C./min in a hot air drier in a nitrogen atmosphere. Minutes, imidization was carried out at 200 ° C. for 1 hour and at 400 ° C. for 1 hour. Then, the metal plate made from SUS was removed, and the laminated board of copper foil / polyesterimide was obtained.

<Polyesterimide film>
The copper foil of the copper foil / polyesterimide laminate obtained above was heated to a ferric chloride solution (Tsurumi Soda Co., Ltd., 40 Baume, ferric chloride 37% or more) at room temperature or 50 ° C. or less. By etching under, polyester imide films with film thicknesses of 26 μm and 12 μm were obtained.

<Weight average molecular weight: Mw>
0.01 g of a polyesterimide precursor solution was measured with a precision balance and dissolved in 10 g of a developing solvent. The developing solvent is 2.61 g of lithium bromide (Aldrich), 1 L of dimethylformamide (Wako Pure Chemical Industries, for liquid chromatography), phosphoric acid aqueous solution (Wako Pure Chemical Industries, purity 85%) 5 .88 g was dissolved. This solution was filtered through a 10 μm filter. Then, TPC guard Column Super HH (trade name, manufactured by Tosoh Corporation) is used as a guard column, and TSK-GEL SUPER HM-H (trade name, manufactured by Tosoh Corporation) is connected in series as a preparative column. The molecular weight was measured at a flow rate of 0.5 ml / min using the above developing solvent. The molecular weight was converted using polystyrene.

<Glass transition temperature: Tg>
Using a thermomechanical analyzer (TMA-50) manufactured by Shimadzu Corporation, a polyesterimide film having a width of 3 mm, a length of 18 mm (length between chucks of 15 mm) and a thickness of 26 μm was measured by thermomechanical analysis. Measure the elongation in the range of 50 ° C to 450 ° C under a nitrogen atmosphere (flow rate 20 ml / min) at a temperature of 50 ° C / min, and determine the glass transition temperature of the polyesterimide film (26 µm thickness) from the inflection point of the obtained curve. Asked.

<Linear thermal expansion coefficient: CTE>
Using a thermomechanical analyzer (TMA-50) manufactured by Shimadzu Corporation, a polyesterimide film having a width of 3 mm, a length of 18 mm (length between chucks of 15 mm) and a thickness of 26 μm was measured by thermomechanical analysis. Measure the elongation at a temperature of 50 ° C to 450 ° C under a nitrogen atmosphere (flow rate of 20 ml / min) at a temperature of 50 ° C / min. Polyesterimide film (thickness 26 µm) ) Was determined.

<Hygroscopic expansion coefficient: CHE>
A polyester imide film having a width of 3 mm, a length of 30 mm (length between chucks of 15 mm), and a thickness of 26 μm was obtained using a thermal mechanical analyzer (TM-9400) and a humidity atmosphere adjustment device (HC-1) manufactured by ULVAC-RIKO. Measure the elongation when the humidity is changed from 30% RH to 70% RH at 23 ° C and a load of 5g, and obtain the hygroscopic expansion coefficient of the polyesterimide film as the average elongation value of the film at 30% RH to 70% RH. It was.

<Flame retardance>
Forty test pieces of polyesterimide film having a thickness of 12 μm were prepared so as to be 20 cm long × 5 cm wide. Among the 40 test pieces, 20 pieces were left in an atmosphere of 23 ° C. and 50% relative humidity for 48 hours or longer (accepted state), and the remaining 20 pieces were aged at 70 ° C. for 168 hours, then at 23 ° C. and relative humidity. It cooled in the desiccator below 20% for 4 hours. VTM-0 evaluation was performed by a flammability test in an atmosphere of 23 ° C. and a relative humidity of 55% using an evaluation method based on the UL94VTM test, using each of five polyesterimide films. (The flame used for the evaluation at this time was a blue flame having a size of 20 mm, and the temperature rise time of copper slag from 100 ° C. to 700 ° C. was 42.9 seconds.)

<Solder heat resistance evaluation>
Cut the copper foil / polyesterimide laminate to a size of 3 cm in length x 3 cm in width, mask the 2.5 cm x 2.5 cm center using a masking tape, under the same conditions as above, The copper foil was etched using a ferric chloride solution (Tsurumi Soda Co., Ltd., 40 Baume, ferric chloride 37% or more) to obtain a test piece. The obtained test piece was allowed to stand for 1 hour or longer in a dryer 105 ° C. and dried, and then left in the solder bath surface set at 300 ° C. for 2 minutes so that the copper foil side was in contact with the copper. The appearance of the foil and the polyesterimide film, such as blistering and wrinkle generation, was evaluated by visual observation, and a case where no change in the appearance was observed was taken as a good result (◯).

<Boiled solder heat resistance evaluation>
The test piece produced similarly to solder heat resistance evaluation was obtained, purified water was put into the container with a reflux condenser, the obtained test piece was immersed, and it left still at 100 degreeC for 2 hours. Then, the test piece was thrown into normal temperature purified water, each test piece was taken out one by one, and the water | moisture content of both surfaces was wiped off with the paper towel. Then, in a solder bath set at 280 ° C., leave it on the surface of the solder bath for 2 minutes so that the copper foil side is in contact with the copper foil and the polyesterimide film. A case where no change in appearance was observed was evaluated as a good result (◯).

<Adhesive strength between copper foil and polyesterimide layer>
About the measuring method of the test piece, it carried out according to JIS C6471 standard. For the test piece, a copper foil / polyesterimide laminate was cut into a size of 15 cm long × 1 cm wide, masked with a 1 cm center width of 3 mm using a masking tape, and chlorinated under the same conditions as above. The copper foil was etched using a ferric solution. The obtained test piece was left to dry at 105 ° C. for 1 hour or longer and then attached to a FR-4 substrate having a thickness of 3 mm with a double-sided adhesive tape. A conductor having a width of 3 mm was peeled off at the interface with the polyesterimide film and attached to an aluminum tape as a grip allowance to prepare a sample.

The obtained sample was fixed to a Shimadzu tensile tester (Autograph AG-10KNI). When fixing, a jig was attached in order to surely peel off in the direction of 90 °, and the load at the time of peeling 50 mm at a speed of about 50 mm / min was measured and calculated as the adhesive strength per 1 cm.

<Elastic modulus>
Using a RTG-1210 type tensile tester manufactured by Orientec Co., Ltd., a polyimide film of 3 mm × 50 mm was stretched at a test length of 50 mm and a test speed of 50 mm / min. The elastic modulus was a tensile elongation of 0.4% of the polyesterimide film. It was calculated from the slope of stress between ˜1.0%. (When a 50 mm sample breaks when it is stretched to 100 mm, it is described as “tensile elongation at break of 100%”.)

<Trouser tear strength>
A polyester imide film is cut out into 50 mm × 150 mm as a sample, and the RTG-1210 type tensile tester (Orientec Co., Ltd. equipped with UR-50ND type load cell) is used, and the method described in JIS K7128-1 Measured at a test speed of 50 mm / min.

<Warpage>
A copper foil / polyesterimide laminate was cut to a size of 10 cm × 10 cm and left in a constant temperature and humidity chamber at 23 ° C. and 50% humidity for one day. Thereafter, the distance between each of the four pieces of the sample and the installation surface was measured, and the average value of the measured distances was taken as the value of warpage. Here, the case of curling to the polyesterimide side was defined as the value (+).
<Melting heat peak temperature (a) ° C., temperature range ΔT = ((b) − (a)) ° C.>

About 5 mg of tetracarboxylic dianhydride (hereinafter referred to as TABP) having an ester structure represented by the formula (19) was weighed, put into an attached aluminum sample container, covered with a lid, and crimped to prepare a measurement sample. Similarly, an unbalanced aluminum sample container and a lid crimped were used as standard substances. A standard substance and a measurement sample are placed in a heating furnace of a differential scanning calorimeter (DSC-60, manufactured by Shimadzu Corporation), and measured at a heating rate of 10 ° C./min in an N ₂ atmosphere at room temperature to 350 ° C. Measurements were made in the range. The peak temperature of the heat of fusion is (a) ° C., and the temperature that is the intersection of the virtual tangent with the contact temperature being the temperature at which the rise to the heat of fusion peak starts, and the straight line along the substantially linear portion of the heat of fusion peak is (b) The temperature range ΔT = ((b) − (a)) ° C. was calculated. The calibration of temperature and heat flow was performed with an indium standard material.

Example 1
(Synthesis Example 1) Synthesis of TABP In a 1 L Separa flask, 100 ml of an N, N-dimethylformamide solution and 200 mmol of trimellitic anhydride chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved, and 0% in an ice bath in a nitrogen atmosphere. Cooled to ° C. Thereafter, a solution of 4,4′-biphenol dissolved in 50 ml of N, N-dimethylformamide and 50 ml of pyridine was dropped at a stirring speed of 100 rpm over 2 hours so as to be 10 ° C. or less, and then at room temperature. Stir for 6 hours. The solution turned red when the dripping was started, and a yellow precipitate was formed as the dripping was completed.

Next, the precipitate was filtered, washed with N, N-dimethylformamide, further washed with water and then filtered twice, and the filtered product was dried to obtain yellowish white crystals containing TABP. Thereafter, the mixture was heat-dried at 130 ° C. for 2 hours at a rate of temperature increase of 10 ° C./min while reducing the pressure in a vacuum dryer to obtain yellow crystals which were unpurified TABP.

<Purification of TABP>
In a 300 ml flask, 10 g of the obtained crude TABP was placed in 150 ml of a γ-butyrolactone solution, heated to 200 ° C. in an oil bath and dissolved with stirring over 30 minutes. At this time, no insoluble matter was observed. Thereafter, heating and stirring of the oil bath were stopped and the mixture was gradually cooled to room temperature.

When the solution was allowed to stand at room temperature, needle-like yellowish white crystals were precipitated while the solution was slowly separated into two layers. The precipitate was collected by filtration, heated and dried at 130 ° C. for 2 hours at a heating rate of 10 ° C./min while reducing the pressure in a vacuum dryer, and then further heated at 200 ° C. at a heating rate of 10 ° C./min. After heating and drying for a period of time and cooling to room temperature while maintaining the degree of vacuum, the pressure was changed to atmospheric pressure, and then high purity TABP yellow crystals of the target product were obtained.

As a result of measuring 5 mg of the obtained TABP with a differential scanning calorimeter (DSC-60, manufactured by Shimadzu Corporation), the peak temperature of heat of fusion (a) 325 ° C., temperature range ΔT = It was ((b)-(a)) = 3.2 ° C.

<Polymerization of polyesterimide precursor, imidization and polyesterimide film property evaluation>
In a well-dried closed reaction vessel with a stirrer, 12.84 mmol of a diamine having an ester structure represented by the formula (33) (hereinafter referred to as BPIP) was added, 61 mL of N-methyl-2-pyrrolidone was added, and the solution was heated to 80 ° C. Warm and dissolve. After dissolution, 13.38 mmol of TABP powder obtained above was gradually added to this solution. By stirring for 30 minutes, the solution viscosity increased rapidly. The mixture was further stirred for 4 hours to obtain a transparent, uniform and viscous polyesterimide precursor solution having repeating units represented by the general formula (1). Here, in the formula (1), _{B 1} is a divalent aromatic group represented by the formula (10).

This polyesterimide precursor solution did not precipitate or gel at all even when allowed to stand at room temperature and 20 ° C. for one month, and showed high solution storage stability.

A 12 μm-thick copper foil (NIPPON ELECTRIC CO., LTD. USLP foil) was allowed to stand on a metal coating table so that the matte surface was the surface. The surface temperature of the coating table was set to 90 ° C., and the polyesterimide precursor solution was applied to the copper foil mat surface with a doctor blade. Then, after leaving still for 30 minutes on a coating table, and further leaving still in a dryer at 100 ° C. for 30 minutes, a laminate of a copper foil / polyesterimide precursor without tackiness (the thickness of the polyesterimide precursor layer is 47 μm and 24 μm) was obtained. Next, the laminate of the copper foil / polyesterimide precursor was fixed with a tape on a SUS metal plate, and 30 ° C. at 150 ° C. at a temperature rising rate of 5 ° C./min in a hot air drier in a nitrogen atmosphere. Minutes, imidization was performed at 200 ° C. for 1 hour and at 400 ° C. for 1 hour. Thereafter, the SUS metal plate was removed, and a copper foil / polyesterimide laminate without curling was obtained. Etching the copper foil of this copper foil / polyesterimide laminate with aqueous ferric chloride (Tsurumi Soda Co., Ltd., 40 Baume, ferric chloride 37% or more) at room temperature or under 50 ° C heating conditions By doing so, the light brown polyesterimide film with a film thickness of 26 micrometers and 12 micrometers was obtained.

The polyesterimide film having a film thickness of 26 μm was not broken by a 180 ° bending test and showed flexibility. It was not soluble in organic solvents such as N-methyl-2-pyrrolidone and dimethylacetamide. Also, TMA measurement showed a low linear thermal expansion coefficient equivalent to 22 ppm / ° C. (average value between 50 ° C. and 200 ° C.) and copper foil. When the hygroscopic expansion coefficient was measured, an extremely low hygroscopic expansion coefficient of 5.0 ppm /% RH (average value between 30% RH and 70% RH) was shown. Evaluation of the flame retardancy of a polyesterimide film having a thickness of 12 μm showed the performance of UL94VTM-0. Moreover, it showed good solder heat resistance and boiling solder heat resistance. The elastic modulus was as low as 5.1 GPa, and the trouser tear strength was 62 mN and a high tear strength in a 26 μm polyesterimide film.

(Example 2)
In a well-dried sealed reaction vessel equipped with a stirrer, 6.42 mmol of BPIP and 6.42 mmol of a diamine having an ester structure represented by the formula (37) (hereinafter referred to as APAB) were added, and 61 mL of N-methyl-2-pyrrolidone was added. Was dissolved by heating to 80 ° C. After dissolution, 13.38 mmol of TABP powder obtained in Example 1 was gradually added to this solution. By stirring for 30 minutes, the solution viscosity increased rapidly. The mixture was further stirred for 4 hours, and had a repeating unit represented by the formula (11) and a repeating unit represented by the formula (12), and the molar ratio of the formula (11) and the formula (12) was the formula (11) / A transparent, uniform and viscous polyesterimide precursor solution having a ratio of formula (12) = 50/50 was obtained. Here, in the formula (12), _{B 2} is a divalent aromatic group represented by the formula (16).

According to the method described in Example 1, film formation and imidization were performed to produce a polyesterimide film, and physical properties were similarly evaluated. The physical property values are shown in Table 1. In addition to the results shown in Table 1, the warpage also showed a good value of 1 mm.

(Example 3)
BPIP 8.99 mmol and APAB 3.85 mmol were placed in a well-closed sealed reaction vessel equipped with a stirrer, N-methyl-2-pyrrolidone 63 mL was added, and the solution was heated to 80 ° C. to dissolve. After dissolution, 13.38 mmol of TABP obtained in Example 1 was gradually added to this solution. By stirring for 30 minutes, the solution viscosity increased rapidly. The mixture is further stirred for 4 hours, has a repeating unit represented by the general formula (11) and a repeating unit represented by the general formula (12), and the molar ratio of the general formula (11) and the general formula (12) is generally A transparent, uniform and viscous polyesterimide precursor solution having a ratio of formula (11) / general formula (12) = 70/30 was obtained. Here, in General Formula (12), B ₂ is a divalent aromatic group represented by Formula (16).

In accordance with the method described in Example 1, film formation and imidization were performed to prepare a polyesterimide film, and physical properties were similarly evaluated. The physical property values are shown in Table 1. In addition to the results shown in Table 1, the warpage was as good as 10 mm.

Example 4
In a well-dried sealed reaction vessel equipped with a stirrer, BPIP 6.88 mmol and diamine having an amide structure represented by formula (38) (hereinafter referred to as DABA) 6.88 mmol were added, and 65 ml of N-methyl-2-pyrrolidone was added, Was dissolved by heating to 80 ° C. After dissolution, 14.33 mmol of TABP powder obtained in Example 1 was gradually added to this solution. By stirring for 30 minutes, the solution viscosity increased rapidly. The mixture is further stirred for 4 hours, has a repeating unit represented by the general formula (11) and a repeating unit represented by the general formula (12), and the molar ratio of the general formula (11) and the general formula (12) is generally A transparent, uniform and viscous polyesterimide precursor solution having a ratio of formula (11) / general formula (12) = 50/50 was obtained. Here, in General Formula (12), B ₂ is a divalent aromatic group represented by Formula (17).

(Example 5)
In a well-closed closed reaction vessel with a stirrer, BPIP 9.63 mmol and diamine having an ester structure represented by the formula (39) (hereinafter referred to as BPTP) 4.13 mmol were added, and 71 mL of N-methyl-2-pyrrolidone was added to the solution. Was dissolved by heating to 80 ° C. After dissolution, 14.79 mmol of TABP powder obtained in Example 1 was gradually added to this solution. By stirring for 30 minutes, the solution viscosity increased rapidly. The mixture is further stirred for 4 hours, has a repeating unit represented by the general formula (11) and a repeating unit represented by the general formula (12), and the molar ratio of the general formula (11) and the general formula (12) is generally A transparent, uniform and viscous polyesterimide precursor solution having a ratio of formula (11) / general formula (12) = 70/30 was obtained. Here, in General Formula (12), B ₂ is a divalent aromatic group represented by Formula (18).

According to the method described in Example 1, film formation and imidization were performed to produce a polyesterimide film, and physical properties were similarly evaluated. The physical property values are shown in Table 1. In addition to the results shown in Table 1, the warpage was as good as -3 mm. Here, −3 mm means warping to the copper foil side.

(Example 6)
In a well-dried sealed reaction vessel with a stirrer, 50 mmol of BPIP was placed and dissolved in 191 mL of N-methyl-2-pyrrolidone, and then 50 mmol of TABP powder obtained in Example 1 was gradually added thereto. After 30 minutes, the solution viscosity increased rapidly. Furthermore, it stirred at 80 degreeC for 4 hours, and obtained the transparent, uniform and viscous polyesterimide precursor. The obtained polyesterimide precursor did not precipitate or gel at all even after being allowed to stand at room temperature and −20 ° C. for one month, and showed high solution storage stability. The intrinsic viscosity of the polyesterimide precursor measured with an Ostwald viscometer in N-methyl-2-pyrrolidone at a concentration of 0.5% by mass at 30 ° C. was 2.8 dL / g. This polyesterimide precursor was filtered with a 5 μm membrane filter under a pressure condition of nitrogen 3 kg / cm ² to obtain a target polyesterimide precursor.

According to the method described in Example 1, a light brown polyesterimide film having a film thickness of 25 μm and 12 μm was obtained by film formation and imidization, and physical properties were similarly evaluated. Table 3 shows the physical property values. This polyesterimide film did not break even in the 180 ° bending test and showed flexibility. Moreover, it did not show any solubility in any organic solvent.

The polyesterimide precursor obtained above was spin-coated on a 6-inch silicon wafer with a spin coater (MS-250, manufactured by Mikasa Co., Ltd.) and allowed to stand at 100 ° C. for 30 minutes in a dryer. A polyesterimide precursor / silicon wafer laminate (polyesterimide precursor layer thickness 17 μm) having no tackiness was obtained. Thereafter, the laminate was imidized in a hot air drier in a nitrogen atmosphere at a heating rate of 5 ° C./min, 150 ° C. for 30 minutes, 200 ° C. for 1 hour, and 400 ° C. for 1 hour. It was. Then, it peeled from the silicon wafer with hydrofluoric acid, and the 10-micrometer-thick polyesterimide film was obtained. When a tensile test was performed on the obtained polyesterimide film, an elastic modulus of 5.4 GPa and an elongation at break of 53% were obtained.

Here, the intrinsic viscosity (η) was measured at 30 ° C. using a Ostwald viscometer for a 0.5% by mass polyesterimide precursor.

(Example 7)
In a 300 ml flask, 10 g of unpurified TABP obtained in Synthesis Example 1 and 150 ml of sulfolane were placed, heated to 180 ° C. in an oil bath, and dissolved with stirring over 30 minutes. Thereafter, TABP was evaluated in the same manner as in Example 1. The obtained TABP was measured with a differential scanning calorimeter (DSC-60, manufactured by Shimadzu Corporation). As shown in Table 2, the peak temperature of the heat of fusion (a) 322.5 ° C., the temperature range Δ T = ((b) − (a)) = 4.5 ° C. The molecular weight was maximized when the charge ratio of acid dianhydride and diamine was 0.99. Moreover, the intrinsic viscosity of the polyesterimide precursor obtained with the preparation ratio of 0.99 was 2.4 dL / g. And according to the method described in Examples 1 and 6, film formation and imidization were performed to produce a polyesterimide film, and physical properties were similarly evaluated. Table 3 shows the physical property values.

(Comparative Example 1)
In a well-dried closed reaction vessel with a stirrer, 9.27 mmol of BPIP was added, 48 mL of N-methyl-2-pyrrolidone was added, and the solution was heated to 80 ° C. to dissolve. After dissolution, 9.66 mmol of a tetracarboxylic dianhydride (hereinafter referred to as TAHQ) powder having an ester structure represented by the formula (20) was gradually added to this solution. By stirring for 30 minutes, the solution viscosity increased rapidly. The mixture was further stirred for 4 hours to obtain a transparent, uniform and viscous polyesterimide precursor solution.

According to the method described in Example 1, film formation and imidization were performed to produce a polyesterimide film, and physical properties were similarly evaluated. The physical property values are shown in Table 1.

It showed linear thermal expansion coefficient close to copper foil, high thermal stability and flexibility, low elastic modulus, and relatively high adhesiveness, but the hygroscopic expansion coefficient was relatively high at 7.6 ppm /% RH, and the tear strength Is as low as 42 mN in a 26 μm polyesterimide film. Further, the flame resistance performance was low with a film having a thickness of 12 μm, and the performance of UL94VTM-0 was not obtained.

(Comparative Example 2)
According to the method described in Example 2, except that TAHQ was used instead of TABP and APAB 10.49 mol and 4,4′-diaminodiphenyl ether (hereinafter referred to as ODA) 2.62 mol were used as the diamine in Example 2. The imide precursor was polymerized, formed into a film and imidized to produce a polyesterimide film, and the physical properties were similarly evaluated. The physical property values are shown in Table 1. Although it showed linear thermal expansion coefficient close to copper foil, high thermal stability and flexibility, the hygroscopic expansion coefficient was relatively high at 8.3 ppm /% RH, the elastic modulus was high at 7.9 GPa, and the adhesive strength Is as low as 0.3 N / mm, and the tear strength is as low as 42 mN in a 26 μm polyesterimide film. Further, the flame resistance performance was low with a film having a thickness of 12 μm, and the performance of UL94VTM-0 was not obtained.

(Comparative Example 3)
In Comparative Example 1, a polyesterimide precursor was polymerized according to the method described in Comparative Example 1 except that the diamine represented by the formula (23) (hereinafter referred to as BAPB) was used as the diamine. A polyesterimide film was prepared and similarly evaluated for physical properties. The physical property values are shown in Table 1.

High glass transition temperature, high adhesiveness, and elastic modulus showed a low value of 5.2 GPa, but the linear thermal expansion coefficient showed a high value of 32 ppm / ° C., and the hygroscopic expansion coefficient was as high as 13.2 ppm /% RH. The tear strength is as low as 45 mN in a 26 μm polyesterimide film. In addition, blistering was observed in the solder heat resistance test, and the flame resistance performance was low with the film having a thickness of 12 μm, and the performance of UL94VTM-0 was not obtained.

(Comparative Example 4)
In Comparative Example 1, a polyester imide precursor was polymerized according to the method described in Comparative Example 1 except that TABP obtained in Example 1 was used instead of TAHQ, and APAB was used as a diamine. A polyesterimide film was prepared and similarly evaluated for physical properties. The physical property values are shown in Table 1. Evaluation of flame retardancy of polyimide film with high thermal stability and flexibility, low hygroscopic expansion coefficient, high tear strength and film thickness of 12μm showed the performance of UL94VTM-0, but the linear thermal expansion coefficient was 13ppm. The coefficient of linear thermal expansion was lower than that of copper foil at / ° C., the adhesive strength was as low as 0.4 N / mm, and the elastic modulus was as high as 7.7 GPa.

The polyesterimide of the present invention can be suitably used as an electrical insulating film, a flexible printed wiring board, a display substrate, an electronic paper substrate, a solar cell substrate, particularly a flexible printed wiring board substrate in various electronic devices.

Claims

A polyesterimide precursor having a repeating unit represented by the following formula (1).

(In the formula (1), Ar is a tetravalent aromatic group represented by the formula (2), and B 1 is a divalent fragrance selected from at least one of the formulas (3) to (9). R 1 represents an alkyl group having 1 to 6 carbon atoms, R 2 to R 4 represent an alkyl group having 1 to 6 carbon atoms and a hydrogen atom, which are independent of each other, and may be the same or different R 5 represents an alkyl group having 1 to 6 carbon atoms, and R 6 to R 9 represent an alkyl group having 1 to 6 carbon atoms and a hydrogen atom.)
In the formula (1) of the polyesterimide precursor according to claim 1, polyesterimide precursor B 1 is characterized by having a repeating unit represented by the formula (3) or (4).
In the formula (1) of the polyesterimide precursor according to claim 1, polyesterimide precursor B 1 is characterized by having a repeating unit represented by the formula (4).
In the formula (1) of the polyesterimide precursor according to claim 1, polyesterimide precursor B 1 is characterized by having a repeating unit represented by the formula (10).
It has a repeating unit represented by the following formula (11) and formula (12), and the molar ratio of formula (11) and formula (12) is formula (11) / formula (12) = 20/80 to 80/20 A polyesterimide precursor, characterized in that

(In the formula (11) and the formula (12), Ar is a tetravalent aromatic group represented by the formula (2). In the formula (12), B 2 is represented by the formulas (13) to (17). Is a divalent aromatic group selected from at least one, and R 10 to R 18 each represents an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and each is independent and may be the same or different Good.)
Of polyesterimide precursor according to claim 5, wherein (12), polyester B 2 is characterized in that it is a repeating unit represented by the formula (16), equation (17) or formula (18) Imide precursor.
Of polyesterimide precursor according to claim 5, wherein (12), polyesterimide precursor B 2 is characterized in that it is a repeating unit represented by the formula (16).
The polyesterimide precursor according to any one of claims 1 to 7, wherein the weight average molecular weight Mw is 30,000 to 400,000.
The polyesterimide precursor according to any one of claims 1 to 8, wherein the ester group-containing tetracarboxylic dianhydride represented by the formula (19) used for obtaining the polyesterimide precursor is a differential scan. The melting heat peak temperature (a) ° C indicated by the calorimeter (DSC), the temperature at the intersection of the tangent line with the temperature at which the rise to the melting heat peak starts and the peak slope settled constant is (b) ° C And a temperature range ΔT = ((b) − (a)) ° C., a polyesterimide precursor satisfying (a) ≧ 322 ° C. and ΔT ≦ 5 ° C.
A polyesterimide obtained by imidizing the polyesterimide precursor according to any one of claims 1 to 9.
A method for producing a polyesterimide, which is obtained by heating or imidizing the polyesterimide precursor according to any one of claims 1 to 9 using a dehydrating reagent.
A laminate having a polyesterimide layer and a metal layer, wherein the polyesterimide layer is composed of the polyesterimide according to claim 10.
The polyesterimide precursor according to any one of claims 1 to 9 is applied on a metal foil, dried, and then imidized by heating or using a dehydrating reagent. The laminated board as described in.
14. A flexible printed wiring board, wherein the metal layer of the laminated board according to claim 12 is patterned into a wiring.