KR20210109458A - Organic solvent, mixed solution and method for producing polyimide film - Google Patents

Abstract

The present invention relates to an organic solvent which allows preparation of a polyamic acid solution having high storage stability and can improve the visibility of a film obtained by using the polyamic acid solution. The present invention also relates to a method for producing a polyimide film which can provide a polyimide film having high visibility by using the organic solvent to inhibit an increase in haze. The organic solvent includes an aprotic polar solvent having a boiling point of 200℃ or lower and water, and has a content of the aprotic polar solvent of 50% or more as determined by gas chromatography and a water content of 40-500 ppm as determined by the Carl Fischer's method. The method for producing a polyimide film uses a mixed solution containing the organic solvent, a tetracarboxylic anhydride ingredient and a diamine ingredient to obtain a polyimide film.

Description

Organic solvent, mixed solution, and the manufacturing method of a polyimide film TECHNICAL FIELD

The present invention provides an organic solvent useful for producing polyimide or a precursor thereof usable as a material for, for example, a circuit board, a mixed solution containing this organic solvent, a tetracarboxylic anhydride component, and a diamine component, and this mixed solution It relates to the manufacturing method of the used polyimide film.

Polyimide has excellent heat resistance, mechanical properties and electrical properties. The polyimide film using this polyimide is widely used for various purposes other than the base material of the circuit wiring board (simply referred to as a circuit board) typified by Flexible Printed Circuits (FPC).

As a method of manufacturing a polyimide film, the tenter method and the casting method are known typically. Among them, the tenter method is a method in which a polyimide precursor (polyamic acid) solution is cast on a rotating drum, peeled off from the rotating drum in the state of a gel film, and cured by heating in a tenter furnace to obtain a polyimide film (for example, See Patent Document 1). In addition, the casting method is a method of apply|coating the solution of polyimide precursors to arbitrary supporting base materials, such as copper foil, drying and hardening by heat processing, and obtaining a polyimide film (for example, refer patent document 2).

In manufacture of a polyimide, tetracarboxylic dianhydride and diamine are made to react normally, and it is set as the polyamic acid which is a precursor. In this state, it is soluble in organic solvents, but when this is heat-treated at a high temperature of 200°C or higher, dehydration ring closure occurs within the molecule, resulting in polyimide insoluble in organic solvents. Therefore, in either case of the tenter method or the casting method, a polyimide is prepared by using the polyimide precursor containing an organic solvent, heat processing this and imidating (hardening) this.

Although a polyimide precursor is unstable with respect to a heat|fever or water in many cases, from a viewpoint of improving storage stability, it is proposed that water content shall be 1 weight% or less (refer patent document 3, for example).

Japanese Patent Laid-Open No. 2000-191806 Japanese Patent Laid-Open No. 2004-322441 Japanese Patent Laid-Open No. 2009-263646

The present invention can prepare a polyamic acid solution with high storage stability regardless of the chemical structure of the finally obtained polyimide, and further, a polyimide film (or polyimide layer) is prepared using the polyamic acid solution. When obtained, it aims at providing the organic solvent which can improve the visibility of the polyimide film (or polyimide layer) obtained. Furthermore, it aims at providing the manufacturing method of the polyimide film which suppresses a raise of a haze by using said organic solvent, and can obtain the polyimide film (or polyimide layer) excellent in visibility.

As a result of the inventors earnestly examining in order to solve the said subject, the boiling point about the organic solvent which forms the mixed solution containing a tetracarboxylic-acid anhydride component and a diamine component, the haze of the polyimide film or polyimide layer obtained Focusing on the effect on (Haze), by appropriately controlling the moisture content of the organic solvent, it was found that the imidization temperature of the polyimide precursor could be increased to reduce the residual solvent after imidization, and further increase the haze From being able to suppress this, the present invention was completed.

That is, the gist of the present invention is as follows.

(1) the following components A and B;

A) an aprotic polar solvent having a boiling point of 200° C. or less under 1 atm;

B) water

contains, the content of the component A measured by gas chromatography is 50% or more, and the content of the component B measured by the Karl Fischer method is in the range of 40 to 500 ppm organic solvent.

(2) The organic solvent according to (1), wherein the component A is at least one member selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

(3) The organic solvent according to (1) or (2), characterized in that it is a solvent used for mixing and polymerizing a tetracarboxylic acid anhydride component and a diamine component to obtain a polyamic acid.

(4) A mixed solution containing the organic solvent according to any one of (1) to (3), a tetracarboxylic anhydride component, and a diamine component.

(5) The mixed solution as described in (4) characterized by containing 50 mol% or more of the monomer which has a biphenyl skeleton among all the monomer components derived from the said tetracarboxylic-acid anhydride component and the said diamine component.

(6) The said diamine component contains 20 mol% or more of the diamine compound represented by following General formula (1), The mixed solution as described in (4) or (5) characterized by the above-mentioned.

[In the general formula (1), the linking group Z represents a single bond or -COO-, and Y is independently a monovalent hydrocarbon group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen or phenyl group, or represents a perfluoroalkyl group or alkenyl group having 1 to 3 carbon atoms, n represents an integer of 1 to 2, and p and q independently represent an integer of 0 to 4.]

(7) the following steps a to d;

a) Step of preparing a mixed solution containing the organic solvent according to any one of (1) to (3), a tetracarboxylic anhydride component, and a diamine component;

b) a step of reacting the tetracarboxylic anhydride component and the diamine component in the mixed solution to obtain a polyamic acid solution;

c) forming a resin film of the polyamic acid by applying the polyamic acid solution on a substrate and drying;

d) a step of heat-treating the resin film and imidizing the polyamic acid to obtain a polyimide film

A method for producing a polyimide film, characterized in that it comprises a.

(8) The method for producing a polyimide film according to (7), wherein the organic solvent is recovered from the solvent vapor generated in the step c and reused as an organic solvent in the mixed solution.

(9) The method for producing a polyimide film according to (7), wherein the organic solvent in the step a is obtained through the step of recovering the solvent vapor generated in the step c.

The organic solvent of the present invention ensures storage stability when applied, for example, as a solution of polyamic acid, suppresses imidization of polyamic acid at low temperature, and reduces the amount of residual solvent after imidization. can In addition, since the organic solvent of the present invention has a boiling point in a specific range and a water content is controlled, a polyimide film can be produced without reducing the physical properties of the polyimide film. In addition, since it is possible to repeatedly reuse the used organic solvent, the manufacturing cost can be significantly reduced, and it is excellent in terms of environment, and for example, production with high yield in continuous production such as roll-to-roll method possible, and has high industrial use value. Since it is possible to suppress the rise of the haze of the polyimide layer in manufacturing the metal-clad laminate, for example, when light is transmitted through the polyimide layer in the FPC mounting process, diffusion is suppressed, and the polyimide that can be recognized by the camera is suppressed. It can be done as a mid-layer.

Next, an embodiment of the present invention will be described.

[Organic solvent]

The organic solvent of this embodiment is the following components A and B;

A) an aprotic polar solvent having a boiling point of 200° C. or less under 1 atm;

B) water

contains

<Component A>

Component A is an aprotic polar solvent having a boiling point of 200° C. or less under 1 atm. From the viewpoint of compatibility with water and ease of control of water content, it is preferable that the lower limit of the boiling point is 120° C. or more. If the boiling point is 200° C. or less, for example, the polyamic acid is easily released out of the system in the process of imidization, and the content of the aprotic polar solvent contained in the polyimide film after imidization can be reduced. The residual amount of the aprotic polar solvent is closely related to the imidation ratio of polyamic acid, and when the ratio of the aprotic polar solvent is large with respect to the imidation ratio, the aprotic polar solvent functions as a plasticizer, It is thought that the haze at the time of film-forming rises because reconformation of a molecular chain occurs. Therefore, the aprotic polar solvent having a boiling point of more than 200°C tends to remain at the time of imidization, and the haze is high.

As a specific example of the aprotic polar solvent which is component A, For example, N,N- dimethylformamide (boiling point; 153 degreeC), N,N- dimethylacetamide (boiling point; 166 degreeC), dimethyl sulfoxide (boiling point; 189). ° C), N,N-diethylacetamide (boiling point; 168 ° C.), 2-butanone (boiling point; 79 ° C.), N-methyl caprolactam (boiling point; 106 ° C.), cyclohexanone (boiling point; 155 ° C.) , dioxane (boiling point; 101° C.), tetrahydrofuran (boiling point; 66° C.), diglyme (boiling point; 162° C.), and the like. Among these, N,N-dimethylformamide, N,N-dimethylacetamide and dimethylsulfoxide are preferable, and N,N-dimethylacetamide is more preferable from the viewpoint of easiness of controlling the physical properties of the resin film of polyamic acid. .

The aprotic polar solvent is contained as a main component of the organic solvent which concerns on this invention, and the density|concentration measured by gas chromatography is 50 % or more. From the viewpoint of easiness of controlling the moisture content, it is preferably 99% or more, more preferably 99.5% or more, still more preferably 99.99% or more. In addition, unless otherwise indicated, % which shows a density|concentration here shows weight%.

In the organic solvent of this invention, you may make it contain solvents other than the component A. Examples of the solvent other than the component A include N-methyl-2-pyrrolidone, hexamethylphosphoramide, dimethyl sulfate, triglyme, and cresol. Two or more types of these solvents may be mixed, Furthermore, aromatic hydrocarbons like xylene and toluene may be mixed.

<Component B>

In the organic solvent of the present invention, the content of water of component B as measured by the Karl Fischer method is within the range of 40 to 500 ppm, preferably within the range of 40 to 450 ppm, more preferably within the range of 40 to 400 ppm good. By controlling within this range, for example, hydrolysis of the polyamic acid in the process of imidization of the polyamic acid is less likely to occur, and water molecules capable of coordinating to the amide group of the polyamic acid exist at low temperature of the polyamic acid. Since the ring-closure reaction of For this reason, with advancing of imidation of polyamic acid, the residual amount of an aprotic polar solvent can be reduced, and it is thought that the haze raise at the time of film-forming can be suppressed.

The organic solvent of this embodiment is suitably used as a solvent used in order to mix and superpose|polymerize a tetracarboxylic-acid anhydride component and a diamine component, and to obtain a polyamic acid, and imidate a polyamic acid, and let it be a polyimide. That is, the organic solvent according to the present invention, the tetracarboxylic acid anhydride component, and the diamine component are included to form a mixed solution, and the organic solvent of this embodiment is a tetracarboxylic acid anhydride derived from the tetracarboxylic acid anhydride component. A polyimide having a high ratio of monomer residues having a biphenyl skeleton (hereinafter, sometimes referred to as "biphenyl skeleton-containing residues") to all monomer residues consisting of residues and diamine residues derived from the diamine component. It can be used suitably for manufacture of the polyimide film which has a polyimide layer.

Among all the monomer components derived from a tetracarboxylic-acid anhydride component and a diamine component, it is preferable to contain 40 mol% or more of the monomer which has a biphenyl skeleton, and it is more preferable to contain 50 mol% or more. That is, the ratio of the biphenyl skeleton-containing residues to all the monomer residues derived from all the monomer components constituting the polyimide is preferably 40 mol% or more, more preferably 50 mol% or more. Here, "acid anhydride residue" means a tetravalent group derived from tetracarboxylic acid anhydride, and "diamine residue" means a divalent group derived from a diamine compound.

A polyimide with a high ratio of a biphenyl skeleton-containing residue tends to form an ordered structure, and the polyimide film which has a polyimide layer containing such a polyimide tends to raise a haze and fall easily in visibility. Moreover, it is thought that an ordered structure is easy to form, so that there is much residual amount of the aprotic polar solvent in the process of imidating a polyamic acid. For this reason, it is estimated that an aprotic polar solvent functions as a plasticizer, and the reconformation of a biphenyl skeleton part is having an influence. For this reason, controlling the residual amount of the aprotic polar solvent after imidation is important for controlling the haze of a polyimide film.

The polyimide layer containing a polyimide with a high ratio of a biphenyl skeleton containing residue is a polyimide layer in manufacturing a metal clad laminated board, for example, WHEREIN: It is preferable to comprise a polyimide film as a main layer. Here, "main" means having the largest thickness in a plurality of polyimide layers constituting the polyimide film, preferably 50% or more, more preferably 60% with respect to the total thickness of the polyimide film. % or more.

In addition, the biphenyl skeleton is a skeleton in which two phenyl groups are single bonded as shown in the following formula (a). Therefore, as a biphenyl skeleton containing residue, a biphenyldiyl group, a biphenyltetrayl group, etc. are mentioned, for example. The aromatic ring contained in these residues may have arbitrary substituents.

As a typical example of a biphenyldiyl group, what is represented by a following formula (b) is mentioned. Representative examples of the biphenyltetrayl group include those represented by the following formula (c). In addition, in a biphenyldiyl group and a biphenyltetrayl group, the bond in an aromatic ring is not limited to the position shown in Formula (b) and Formula (c), Moreover, as mentioned above, it is contained in these residues. The aromatic ring used may have arbitrary substituents.

The biphenyl skeleton-containing residue is a structure derived from a raw material monomer, and may be derived from tetracarboxylic anhydride, may be derived from a diamine compound, or may be derived from both.

As a diamine residue contained in a polyimide, the diamine residue derived from the diamine compound represented by General formula (1) is mentioned preferably.

In general formula (1), linking group Z represents a single bond or -COO-, Y is independently a C1-C3 monovalent hydrocarbon group optionally substituted with a halogen or a phenyl group, or a C1-C3 alkoxy group or carbon number A perfluoroalkyl group or an alkenyl group of 1 to 3 is represented, n is an integer of 1 to 2, p and q independently represent an integer of 0 to 4; Here, "independently" means that a plurality of substituents Y and integers p and q may be the same as or different from each other in the formula (1).

The diamine residue derived from the diamine compound represented by the general formula (1) (hereinafter, may be referred to as "diamine residue (1)") easily forms an ordered structure and can improve dimensional stability. From this point of view, the diamine residue (1) is 20 mole parts or more, preferably within the range of 70 to 99 mole parts, and more preferably within the range of 80 to 99 mole parts with respect to 100 mole parts of the total diamine residues contained in the polyimide. It is better to contain in

Preferred specific examples of the diamine residue (1) include 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-diethyl-4,4'-diaminobiphenyl ( m-EB), 2,2'-diethoxy-4,4'-diaminobiphenyl (m-EOB), 2,2'-dipropoxy-4,4'-diaminobiphenyl (m-POB) ), 2,2'-n-propyl-4,4'-diaminobiphenyl (m-NPB), 2,2'-divinyl-4,4'-diaminobiphenyl (VAB), 4,4 and diamine residues derived from diamine compounds such as '-diaminobiphenyl and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB). Among these, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) is particularly preferable because it tends to form an ordered structure.

In addition, in order to lower the elastic modulus of the polyimide film and improve elongation and bending resistance, the polyimide is at least one diamine selected from the group consisting of diamine residues represented by the following general formulas (2) and (3). It is preferred to include residues.

In the formulas (2) and (3), R ₅ , R ₆ , R ₇ and R ₈ are each independently a halogen atom or an alkyl group or an alkoxy group optionally substituted with a halogen atom having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. represents an alkenyl group of, and X is independently -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -CO-, -COO-, -SO ₂ represents a divalent group selected from -, -NH- or -NHCO-, and X ₁ and X ₂ are each independently a single bond, -O-, -S-, -CH ₂ -, -CH(CH ₃ )- , -C(CH ₃ ) ₂ -, -CO-, -COO-, -SO ₂ -, -NH- or -NHCO- represents a divalent group selected from, but _{both X 1} and X ₂ are single bonds Except for the case, j, k, l, and m independently represent an integer of 0 to 4.

_{In addition, "independently" means a plurality of linking groups X, linking groups X 1} and X ₂ , and a plurality of substituents R ₅ , R ₆ , R _{7 in} either or both of the formulas (2) and (3). , R ₈ , and the integers j, k, l, and m may be the same as or different from each other.

Since the diamine residue represented by General formula (2) and (3) has a flexible site|part, flexibility can be provided to a polyimide. Here, since the diamine residue represented by General formula (3) has four benzene rings, in order to suppress an increase in the coefficient of thermal expansion (CTE), it is preferable to make the terminal group couple|bonded with a benzene ring into para position. In addition, from the viewpoint of suppressing an increase in the coefficient of thermal expansion (CTE) while imparting flexibility to the polyimide, the diamine residues represented by the general formulas (2) and (3) are added to 100 molar parts of the total diamine residues contained in the polyimide. To this, it is preferable to contain it within the range of 2 to 30 mole parts.

In the diamine residue represented by the general formula (2), at least one of m, n and o is preferably 0, and as _{a preferable example of the groups R 5} , R _{6 and R 7} , which may be substituted with a halogen atom having 1 to 4 carbon atoms and an alkyl group, an alkoxy group having 1 to 3 carbon atoms, or an alkenyl group having 2 to 3 carbon atoms. Moreover, as a preferable example of the coupling group X in General formula (2), -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -SO ₂ -, or -CO- is mentioned. Preferred specific examples of the diamine residue represented by the general formula (2) include 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,4-bis(4-aminophenoxy)benzene (TPE-) Q), bis(4-aminophenoxy)-2,5-di-tert-butylbenzene (DTBAB), 4,4-bis(4-aminophenoxy)benzophenone (BAPK), 1,3-bis[ and diamine residues derived from diamine compounds such as 2-(4-aminophenyl)-2-propyl]benzene and 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene.

Diamine residue represented by the general formula (3) is preferably in the range of at least one of m, n, o and p 0, also a group of the R _5, R _6, R ₇ and R ₈ Preferred examples of, 1 to 4 carbon atoms and an alkyl group optionally substituted with a halogen atom, an alkoxy group having 1 to 3 carbon atoms, or an alkenyl group having 2 to 3 carbon atoms. _{Moreover, as a preferable example of linking group X 1} and X ₂ in general formula (3), a single bond, -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -SO ₂ -, or -CO - can be heard. However, from a viewpoint of providing a bending site|part _{, the case where both of coupler X 1} and X ₂ is a single bond shall be excluded. As a preferable specific example of the diamine residue represented by General formula (3), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 2,2'-bis[4-(4-aminophenoxy) Derived from diamine compounds such as phenyl]propane (BAPP), 2,2'-bis[4-(4-aminophenoxy)phenyl]ether (BAPE), and bis[4-(4-aminophenoxy)phenyl]sulfone and diamine residues to be used.

Among the diamine residues represented by the general formula (2), a diamine residue derived from 1,3-bis(4-aminophenoxy)benzene (TPE-R) (sometimes referred to as “TPE-R residue”) is Particularly preferred, among the diamine residues represented by the general formula (3), a diamine residue derived from 2,2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) (referred to as “BAPP residue”) may be used) is particularly preferred. Since the TPE-R residue and the BAPP residue have a flexible site, the elastic modulus of the polyimide film can be lowered and flexibility can be imparted. In addition, since the BAPP residue has a large molecular weight, the effect of lowering the imide group concentration of the polyimide and suppressing moisture absorption of the polyimide film can also be expected.

Examples of other diamine residues contained in the polyimide include m-phenylenediamine (m-PDA), 4,4'-diaminodiphenyl ether (4,4'-DAPE), 3,3'-diamino Diphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4, 4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 3,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfide, 3,3'-diamino Diphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 3 ,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 2,2-bis-[4-(3-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy) Phenyl]sulfone, bis[4-(3-aminophenoxy)biphenyl, bis[1-(3-aminophenoxy)]biphenyl, bis[4-(3-aminophenoxy)phenyl]methane, bis[ 4-(3-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)]benzophenone, 9,9-bis[4-(3-aminophenoxy)phenyl]fluorene, 2, 2-bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis-[4-(3-aminophenoxy)phenyl]hexafluoropropane, 3,3'-dimethyl -4,4'-diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6- Diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3''-diamino-p-terphenyl, 4, 4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, bis( p-aminocyclohexyl)methane, bis(p-β-amino-t-butylphenyl)ether, bis(p-β-methyl-δ-aminopentyl)benzene, p-bis(2-methyl-4-aminopentyl) )benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis(β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2, 5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole and diamine residues derived from aromatic diamine compounds such as piperazine and the like.

Although there is no restriction|limiting in particular as a tetracarboxylic acid residue contained in polyimide, For example, tetracarboxylic acid residue derived from pyromellitic dianhydride (PMDA) (hereinafter also referred to as PMDA residue), 3,3',4 A tetracarboxylic acid residue derived from ,4'-biphenyltetracarboxylic dianhydride (BPDA) (hereinafter also referred to as a BPDA residue) is preferably used. These tetracarboxylic acid residues tend to form an ordered structure. In addition, the PMDA residue is a residue responsible for the control of the coefficient of thermal expansion and the control of the glass transition temperature. Moreover, since the BPDA residue has no polar group among the tetracarboxylic acid residues and has a relatively large molecular weight, the effect of lowering the imide group concentration of the polyimide and suppressing moisture absorption of the polyimide film can also be expected.

From this point of view, the total amount of PMDA residues and/or BPDA residues is preferably 50 mol parts or more, more preferably 50 to 100 parts by mol relative to 100 mol parts of all tetracarboxylic acid residues contained in the polyimide, Most preferably, it is in the range of 70 to 100 molar parts.

Examples of the other tetracarboxylic acid residue contained in the polyimide include 2,3',3,4'-biphenyltetracarboxylic dianhydride and 2,2',3,3'-biphenyltetracarboxyl. Acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 2,2',3,3'-, 2,3,3 ',4'- or 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,3',3,4'-diphenylethertetracarboxylic dianhydride, bis(2,3 -dicarboxyphenyl) ether dianhydride, 3,3'', 4,4''-, 2,3,3'', 4''- or 2,2'', 3,3''-p-ter Phenyltetracarboxylic dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)-propane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl)methane dianhydride , bis(2,3- or 3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(2,3- or 3,4-dicarboxyphenyl)ethane dianhydride, 1,2,7,8 -, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5 ,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1 ,2,5,6-tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7- ( Or 1,4,5,8-) tetrachloronaphthalene-1,4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 2,3,8,9-, 3 ,4,9,10-, 4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic acid dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5- tetracarboxylic acid and tetracarboxylic acid residues derived from aromatic tetracarboxylic dianhydrides such as dianhydride and 4,4'-bis(2,3-dicarboxyphenoxy)diphenylmethane dianhydride.

Polyimide WHEREIN: By selecting the type of the said tetracarboxylic acid residue and a diamine residue, and each molar ratio in the case of applying 2 or more types of tetracarboxylic acid residue or a diamine residue, a thermal expansion coefficient, a storage modulus, and a tensile modulus of elasticity etc can be controlled. Moreover, when it has two or more structural units of a polyimide, although it may exist as a block and may exist randomly, it is preferable to exist randomly from a viewpoint of suppressing in-plane fluctuation|variation.

[Method for producing polyimide film]

The manufacturing method of the polyimide film of this embodiment is following process a-d;

a) the process of preparing the mixed solution containing the organic solvent which concerns on this invention, a tetracarboxylic-acid anhydride component, and a diamine component;

b) a step of reacting the tetracarboxylic anhydride component and the diamine component in the mixed solution to obtain a solution of polyamic acid;

c) forming a resin film of the polyamic acid by applying the polyamic acid solution on a substrate and drying;

d) a step of heat-treating the resin film and imidizing the polyamic acid to obtain a polyimide film

can be provided.

<Process a>

The organic solvent used in the process a contains the said components A and B.

<Process b>

In step b, for example, a tetracarboxylic anhydride and a diamine compound are dissolved in an organic solvent in approximately equimolar amounts, stirred at a temperature within the range of 0 to 100°C for 30 minutes to 24 hours, and polymerization reaction is performed, and a solution of polyamic acid get In the case of reaction, a reaction component is melt|dissolved so that the polyamic acid produced|generated may become in the range of 5-30 mass % in a solvent, Preferably it exists in the range of 10-20 mass %.

The viscosity of the solution of polyamic acid is preferably in the range of 500 cps to 100,000 cps. When it deviates from this range, it will become easy to generate|occur|produce defects, such as thickness nonuniformity and a stripe, in a film at the time of the coating operation by a coater etc.

<Process c and process d>

The polyamic acid solution obtained in step b is applied on a substrate, and then dried and imidized (or cured) by heat treatment. As the method of heat treatment, generally, heat treatment such as heating for a period of time within a range of 1 to 60 minutes under a temperature condition within a range of 80 to 400°C is suitably employed. At that time, in order to advance imidization of the polyamic acid, a heat treatment for evaporating the organic solvent to be dissolved or miscible and a heat treatment for releasing the organic solvent coordinated with the polyamic acid to the outside of the system are required.

After forming the resin film of polyamic acid in the process c, you may imidate on a base material, and you may peel a resin film from a base material, and may imidate it. In the case where the polyimide film is a polyimide film including a plurality of polyimide layers, as an aspect of the method for producing the polyimide film, for example, applying and drying a solution of polyamic acid on a substrate is repeated a plurality of times. , a method of imidization (hereinafter, the casting method), a method of imidization after coating and drying in a state in which polyamic acid is simultaneously laminated in multiple layers by multilayer extrusion (hereinafter, the multilayer extrusion method), etc. can

Even when the polyimide film is a single layer or a multiple layer, it is preferable to complete imidization of the polyamic acid on the substrate. Since the resin film of polyamic acid is imidated while being fixed to the base material, it is possible to suppress the expansion/contraction change of the polyimide layer in the imidization process, and to maintain the thickness and dimensional accuracy of the polyimide film.

<Reference>

About the base material used in process c, it is used for the objective of reinforcing a polyimide film (or a polyimide layer), and suppressing the expansion-contraction change of a polyimide film, and maintaining dimensional accuracy. In addition, the base material becomes the object to which the solution of polyamic acid is apply|coated, and shapes, such as a cut sheet form, a roll form, or an endless belt form, can be used. In order to obtain productivity, it is efficient to set it as the form of roll form or endless belt form, and set it as the form which can produce continuously. Moreover, it is preferable that the support base material is roll shape formed in the elongate shape from a viewpoint of expressing the improvement effect of the dimensional accuracy of a polyimide film more largely.

Examples of the material of the base material include metals, ceramics, resins, and those having heat resistance such as carbon, but metals are preferred from the viewpoint of thermal conductivity and flexibility. Therefore, as a base material, metal films, for example, copper foil, aluminum foil, stainless steel foil, iron foil, silver foil, gold foil, zinc foil, indium foil, tin foil, zirconium foil, tantalum foil, titanium foil, cobalt foil, and these alloy foil is mentioned. When a polyimide film is applied as an insulating layer of a circuit wiring board and a base material is applied as a wiring layer of a circuit wiring board, copper foil or copper alloy foil is preferable as a base material. In addition, when peeling and using a polyimide film from a base material, a smooth stainless steel belt, a stainless drum, etc. can be used suitably as a base material.

The inside of the range of 5-35 micrometers is preferable, for example, and, as for the thickness of the metal foil as a base material, the inside of the range of 9-18 micrometers is more preferable. When metal foil is thicker than 35 micrometers, the flexibility and bendability as a laminated body containing a polyimide layer and a metal foil layer will worsen. On the other hand, when metal foil is thinner than 5 micrometers, in the manufacturing process as a laminated body, adjustment of tension|tensile_strength etc. becomes difficult, and it will become easy to produce defects, such as wrinkles. Moreover, these metal foils may give chemical or mechanical surface treatment to the surface for the purpose of improvement, such as adhesive force, and may give chemical surface treatment for the purpose of rust prevention.

<Recovery and Reuse of Organic Solvents>

It is preferable to have a process of recovering|recovering the organic solvent from the solvent vapor|steam generated in process c. The organic solvent is recovered by recovering the organic solvent from the solvent vapor generated by drying after applying the polyamic acid solution, but the organic solvent may also be recovered from the solvent vapor generated in the heat treatment step of step d. . The solvent recovered in this way is reused as the organic solvent in step a.

The method for recovering and reusing the solvent vapor is not particularly limited, but for example, a cooling method, an adsorption method using a solid adsorbent such as activated carbon or zeolite, an adsorption method using a liquid non-volatile solvent, an absorption method using water, etc. can be heard Moreover, a general solvent recovery apparatus can be used, for example, a multiple effect vapor type solvent recovery apparatus, a heat pump type solvent recovery apparatus, a heat pump type multiple effect type concentration apparatus, an evaporation concentration apparatus, etc. are mentioned.

Solvent vapor is hydrophilic and easily soluble in water, has a higher boiling point than water and is less than the vapor pressure of water, so it is easier to evaporate than water. It is preferable to include a step of dissolving the water-soluble substance to be used in water. The recovered solution can be concentrated by evaporating water having a high vapor pressure by thermal energy supplied from the outside. As the thermal energy, it is preferable to use the heat of the solvent vapor, but when the solvent vapor is low temperature, heat by a heater or the like may be used. The concentrated recovered liquid may be subjected to acid treatment, alkali treatment, activated carbon treatment, or the like as necessary.

In addition, the concentrated recovery liquid can be regenerated and reused as an organic solvent of the raw material in step a by purification such as distillation, for example.

When using the organic solvent containing the recycled solvent, it is preferable that 50 volume% or more of the organic solvent used as a raw material is a recycled solvent. When the ratio of the reused solvent to the organic solvent used as a raw material shall be 50 volume% or more, a cost advantage increases.

Example

The features of the present invention will be described in more detail with reference to Examples below. However, the scope of the present invention is not limited to the examples. In addition, in the following examples, various measurements and evaluation are based on the following unless otherwise indicated.

[Evaluation of moisture content]

The moisture content of the regenerated solvent was measured using a Karl Fischer moisture measuring device (a trace moisture measuring device AQ-300, manufactured by Hiranuma Sangyo).

[Measurement of solvent purity]

Solvent purity was measured using a gas chromatograph (column: G-100). It is the value which showed the ratio of the main peak area of the solvent in the obtained total peak area in percentage.

[Measurement of viscosity]

The viscosity in 25 degreeC was measured using the E-type viscometer (The Brookfield company make, brand name; DV-II+Pro). The rotation speed was set so that the torque might be 10% to 90%, and after 2 minutes had elapsed from the start of the measurement, the value when the viscosity was stabilized was read.

[Measurement of surface roughness of copper foil]

For the surface roughness of copper foil, AFM (Brooker AXS, brand name; Dimension Icon type SPM), probe (Brooker AXS, brand name; TESPA (NCHV), tip curvature radius 10nm, spring constant 42N/m) Using, it measured in the range of 80 micrometers x 80 micrometers of the copper foil surface in tapping mode, and calculated|required 10-point average roughness (Rzjis).

[Evaluation of HAZE]

Using a haze measuring apparatus (turbidimeter: Nippon Denshoku Kogyo Co., Ltd. make, brand name; NDH5000), it carried out by the measuring method of ASTM D1003 about the polyimide film of 5 cm x 5 cm size.

[Measurement of coefficient of thermal expansion (CTE)]

Using a thermomechanical analyzer (manufactured by Bruker, trade name; 4000SA), a polyimide film having a size of 3 mm (coating width direction) x 20 mm (coating length direction) was applied at a constant temperature increase rate of 30°C while applying a load of 5.0 g. The temperature was raised to 260°C, and the temperature was maintained at that temperature for 10 minutes, then cooled at a rate of 5°C/min, and the average coefficient of thermal expansion (coefficient of thermal expansion) from 250°C to 100°C was obtained.

The symbol used for the Example and the reference example shows the following compounds.

PMDA: pyromellitic dianhydride

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl

TPE-Q: 1,4-bis(4-aminophenoxy)benzene

BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane

Bisaniline-P: 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene (manufactured by Mitsui Chemicals Fine, trade name; bisaniline-P)

DMAc: N,N-dimethylacetamide

DMF: N,N-dimethylformamide

[Synthesis Example 1]

14.20 parts by mass of m-TB (0.067 parts by mol) and 3.45 parts by mass of TPE-Q (0.012 parts by mol) and DMAc (water content of 10 wt ppm, purity of 99.9% or more) of a new product in an amount such that the solid content concentration after polymerization is 15 wt % in the reaction tank It was added and stirred at room temperature to dissolve. Next, after adding 12.66 parts by mass of PMDA (0.058 mol parts) and 5.69 parts by mass of BPDA (0.019 mol parts), stirring was continued for 3 hours at room temperature to perform polymerization reaction to obtain polyamic acid solution a-1. The viscosity of the polyamic acid solution a-1 was 34,900 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 30,100 cps.

[Synthesis Example 2]

14.49 parts by mass of m-TB (0.068 parts by mol), 1.11 parts by mass of TPE-Q (0.004 parts by mol) and 1.31 parts by mass of bisaniline-P (0.004 mol parts) and a new product in an amount such that the solid content concentration after polymerization is 15% by weight in the reactor DMAc (water content 10 wt ppm, purity 99.9% or more) was added and dissolved by stirring at room temperature. Next, after adding 8.13 mass parts PMDA (0.037 mol part) and 10.97 mass parts BPDA (0.037 mol part), stirring was continued at room temperature for 3 hours, the polymerization reaction was carried out, and the polyamic-acid solution b-1 was obtained. The viscosity of the polyamic acid solution b-1 was 35,500 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 32,800 cps.

[Synthesis Example 3]

14.20 parts by mass of m-TB (0.067 parts by mol) and 3.45 parts by mass of TPE-Q (0.012 mol parts) and DMF of a new product in an amount such that the solid content concentration after polymerization is 15% by weight (water content 15 wt ppm, purity 99.9% or more) was added to the reaction tank It was added and stirred at room temperature to dissolve. Next, after adding 12.66 parts by mass of PMDA (0.058 mol parts) and 5.69 parts by mass of BPDA (0.019 mol parts), stirring was continued for 3 hours at room temperature, followed by polymerization reaction to obtain polyamic acid solution a-2. The viscosity of the polyamic acid solution a-2 was 32,700 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 28,900 cps.

[Synthesis Example 4]

18.71 parts by mass of BAPP (0.046 mol parts) and a new DMAc (moisture content of 10 wt ppm, purity of 99.9% or more) in an amount such that the solid content concentration after polymerization is 12% by weight were added to the reaction tank, and stirred at room temperature to dissolve. Next, after adding 10.09 mass parts PMDA (0.046 mol part), stirring was continued at room temperature for 3 hours, the polymerization reaction was performed, and the polyamic-acid solution c-1 was obtained. The viscosity of the polyamic acid solution c-1 was 2,100 cps.

[Synthesis Example 5]

18.71 parts by mass of BAPP (0.046 mol parts) and new DMF (moisture content: 15 wt ppm, purity of 99.9% or more) in an amount such that the solid content concentration after polymerization is 12% by weight were added to the reaction tank, and stirred at room temperature to dissolve. Subsequently, after adding 10.09 mass parts of PMDA (0.046 mol part), stirring was continued at room temperature for 3 hours, the polymerization reaction was performed, and the polyamic-acid solution c-2 was obtained. The viscosity of the polyamic acid solution c-2 was 1,600 cps.

[Production Example 1]

After the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to one side of a long rolled copper foil (Rzjis = 0.88 μm) having a thickness of 18 μm and a width of 1,080 mm to a thickness of 2.5 μm after curing, The solvent was removed by heating and drying at 130°C. Then, on the dried polyamic acid solution c-1, the polyamic acid solution a-1 prepared in Synthesis Example 1 was uniformly applied to a thickness of 20 μm after curing, and then the solvent was removed by heating at 130° C. . Further, on the dried polyamic acid solution a-1, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to a thickness of 2.5 μm after curing, and then the solvent was removed by heating at 130° C. . At this time, the said process used for application|coating and heat treatment of the polyamic acid solution c-1, the polyamic acid solution a-1, and the polyamic acid solution c-1 was made into the 1st heat treatment process. Then, through the 2nd heat treatment process of heating up from 160 degreeC to 360 degreeC and imidating, the copper clad laminated body 1 containing the polyimide resin layer of 25 micrometers in thickness was obtained. With respect to the obtained copper clad laminated board A-1, copper foil was etched away using ferric chloride aqueous solution, and the multilayer polyimide film A-1 was prepared. The haze of this multilayer polyimide film A-1 was 75.30 %, and CTE was 21 ppm/K.

(Process of recovering and regenerating the solvent)

At this time, the solvent vapor generated in the first heat treatment process was dissolved in gas-liquid contact with water to obtain a solvent recovery solution, and then separated by distillation into solvent and water to obtain regenerated DMAc1.

At this time, the purity of the regenerated DMAc1 was 99.99 (%) and the moisture content was 41 (wt ppm).

[Production Example 2]

After the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to one side of a long rolled copper foil (Rzjis = 0.88 μm) having a thickness of 18 μm and a width of 1,080 mm to a thickness of 2.5 μm after curing, The solvent was removed by heating and drying at 130°C. Then, on the dried polyamic acid solution c-1, the polyamic acid solution b-1 prepared in Synthesis Example 2 was uniformly applied to a thickness of 20 μm after curing, and then the solvent was removed by heating and drying at 130° C. . Further, on the dried polyamic acid solution b-1, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to a thickness of 2.5 μm after curing, and then the solvent was removed by heating and drying at 130° C. .

At this time, the said process used for application|coating and heat treatment of the polyamic acid solution c-1, the polyamic acid solution b-1, and the polyamic acid solution c-1 was made into the 1st heat treatment process. Then, the copper clad laminated body B-1 containing a 25-micrometer-thick multilayer polyimide resin layer was obtained through the 2nd heat treatment process of heating up and imidating from 160 degreeC to 360 degreeC. With respect to the obtained copper clad laminated board B-1, copper foil was etched away using ferric chloride aqueous solution, and multilayer polyimide film B-1 was prepared. The haze of this multilayer polyimide film B-1 was 81.83 %, and CTE was 23 ppm/K.

The solvent vapor generated in the first heat treatment step was dissolved by contacting water and gas-liquid in the same manner as in Production Example 1 to obtain a solvent recovery solution, followed by separation with a solvent and water by distillation to obtain regenerated DMAc2. Further, the same production as in Production Example 2 was performed twice, and the solvent vapor generated in the first heat treatment step was recovered and separated from water to obtain regenerated DMAc3 and regenerated DMAc4.

Table 1 shows the results of measuring the purity and moisture content of the obtained regenerated DMAc.

[Production Example 3]

After the polyamic acid solution c-2 prepared in Synthesis Example 5 was uniformly applied to one side of a long rolled copper foil (Rzjis = 0.88 μm) having a thickness of 18 μm and a width of 1,080 mm so that the thickness after curing was 2.5 μm, The solvent was removed by heating and drying at 130°C. Then, on the dried polyamic acid solution c-2, the polyamic acid solution a-2 prepared in Synthesis Example 3 was uniformly applied to a thickness of 20 μm after curing, and then the solvent was removed by heating and drying at 130° C. . Further, on the dried polyamic acid solution a-2, the polyamic acid solution c-2 prepared in Synthesis Example 5 was uniformly applied to a thickness of 2.5 μm after curing, and then the solvent was removed by heating at 130° C. . At this time, the said process used for application|coating and heat treatment of the polyamic acid solution c-2, the polyamic acid solution a-2, and the polyamic acid solution c-2 was made into the 1st heat treatment process. Then, the copper clad laminated body A-2 containing a 25-micrometer-thick multilayer polyimide resin layer was obtained through the 2nd heat treatment process of heating up and imidating from 160 degreeC to 360 degreeC. With respect to the obtained copper clad laminated board A-2, copper foil was etched away using ferric chloride aqueous solution, and the multilayer polyimide film A-2 was prepared. The haze of this multilayer polyimide film A-2 was 72.16 %, and CTE was 20 ppm/K.

The solvent vapor generated in the first heat treatment step was dissolved by contacting water and gas-liquid in the same manner as in Production Example 1 to obtain a solvent recovery solution, followed by separation with a solvent and water by distillation to obtain regenerated DMF1.

At this time, the purity of the regenerated DMF1 was 99.98 (%) and the moisture content was 246 (wt ppm).

[Production Example 4]

After the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to one side of a long rolled copper foil (Rzjis = 0.88 μm) having a thickness of 18 μm and a width of 1,080 mm to a thickness of 2.5 μm after curing, The solvent was removed by heating and drying at 130°C. Then, on the dried polyamic acid solution c-1, the polyamic acid solution a-2 prepared in Synthesis Example 3 was uniformly applied to a thickness of 20 μm after curing, and then the solvent was removed by heating and drying at 130° C. . Further, on the dried polyamic acid solution a-2, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to a thickness of 2.5 μm after curing, and then the solvent was removed by heating and drying at 130° C. . At this time, the said process used for application|coating and heat treatment of the polyamic acid solution c-1, the polyamic acid solution a-2, and the polyamic acid solution c-1 was made into the 1st heat treatment process. Then, the copper clad laminated body A-3 which consists of a 25-micrometer-thick multilayer polyimide resin layer was obtained through the 2nd heat treatment process of heating up and imidating from 160 degreeC to 360 degreeC. About the obtained copper clad laminated board A-3, copper foil was etched away using ferric chloride aqueous solution, and the multilayer polyimide film A-3 was prepared. The haze of this multilayer polyimide film A-3 was 72.52 %, and CTE was 20 ppm/K.

The solvent vapor generated in the first heat treatment step was dissolved in gas-liquid contact with water in the same manner as in Production Example 1 to obtain a solvent recovery solution, and then separated by distillation with a solvent and water to obtain a regenerated DMF/DMAc mixed solution 1.

At this time, the regenerated DMF/DMAc mixed solution 1 had a purity of 99.98 (%) and a moisture content of 121 (wt ppm).

[Example 1]

14.20 parts by mass of m-TB (0.067 mol parts) and 3.45 parts by mass of TPE-Q (0.012 mol parts) and regenerated DMAc1 in an amount such that the solid content concentration after polymerization is 15% by weight were added to the reaction tank, and stirred at room temperature to dissolve. Then, after adding 12.66 mass parts PMDA (0.058 mol part) and 5.69 mass parts BPDA (0.019 mol part), stirring was continued at room temperature for 3 hours, the polymerization reaction was carried out, and the polyamic-acid solution a-3 was obtained. The viscosity of the polyamic acid solution a-3 was 31,200 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 26,500 cps.

Next, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to one side of a long rolled copper foil (Rzjis = 0.88 μm) having a thickness of 18 μm and a width of 1,080 mm so that the thickness after curing was 2.5 μm. Then, the solvent was removed by heating and drying at 130°C. Then, the polyamic acid solution a-3 was uniformly coated on the dried polyamic acid solution c-1 to a thickness of 20 μm after curing, and then the solvent was removed by heating and drying at 130°C. Further, on the dried polyamic acid solution a-3, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to a thickness of 2.5 μm after curing, and then the solvent was removed by heating and drying at 130° C. . Then, the copper clad laminated body A-3 which consists of a 25-micrometer-thick multilayer polyimide resin layer was obtained through the 2nd heat treatment process of heating up and imidating from 160 degreeC to 360 degreeC. About the obtained copper clad laminated board A-3, copper foil was etched away using ferric chloride aqueous solution, and the multilayer polyimide film A-3 was prepared. The haze of this multilayer polyimide film A-3 was 71.78 %, and CTE was 21 ppm/K.

[Example 2]

A polyamic acid solution a-4, a copper clad laminate A-4, and a multilayer polyimide film A-4 were obtained in the same manner as in Example 1 except that the DMAc used was changed to the regenerated DMAc2.

The obtained polyamic acid solution a-4 had a viscosity of 28,700 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 19,100 cps. Moreover, the haze of the multilayer polyimide film A-4 was 65.20 %, and CTE was 22 ppm/K.

[Example 3]

A polyamic acid solution a-5, a copper clad laminate A-5, and a multilayer polyimide film A-5 were obtained in the same manner as in Example 1 except that the DMAc used was changed to the regenerated DMAc3.

The obtained polyamic acid solution a-5 had a viscosity of 26,500 cps. Moreover, the viscosity at the time of storing for 20 days at 23 degreeC and 50 %RH was 15,500 cps. Moreover, the haze of the multilayer polyimide film A-5 was 61.71 %, and CTE was 22 ppm/K.

[Example 4]

Polyamic acid solution a-6, copper clad laminate A in the same manner as in Example 1, except that the DMAc used was changed to recycled DMF1, and the polyamic acid solution c-1 was changed to the polyamic acid solution c-2. -6, multilayer polyimide film A-6 was obtained.

The obtained polyamic acid solution a-6 had a viscosity of 26,100 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 13,700 cps. Moreover, the haze of the multilayer polyimide film A-6 was 60.08 %, and CTE was 21 ppm/K.

[Example 5]

14.49 parts by mass of m-TB (0.068 parts by mol), 1.11 parts by mass of TPE-Q (0.004 parts by mol) and 1.31 parts by mass of bisaniline-P (0.004 mol parts) in the reactor, and regenerated DMAc2 in an amount such that the solid content concentration after polymerization is 15% by weight was added and dissolved by stirring at room temperature. Then, after adding 8.13 mass parts PMDA (0.037 mol part) and 10.97 mass parts BPDA (0.037 mol part), stirring was continued at room temperature for 3 hours, the polymerization reaction was carried out, and the polyamic-acid solution b-2 was obtained. The viscosity of the polyamic acid solution b-2 was 29,900 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 22,500 cps.

Next, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to one side of a long rolled copper foil (Rzjis = 0.88 μm) having a thickness of 18 μm and a width of 1,080 mm so that the thickness after curing was 2.5 μm. Then, the solvent was removed by heating and drying at 130°C. Next, the polyamic acid solution b-2 was uniformly coated on the dried polyamic acid solution c-1 to a thickness of 20 μm after curing, and then the solvent was removed by heating and drying at 130°C. Further, on the dried polyamic acid solution b-2, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to a thickness of 2.5 μm after curing, and then the solvent was removed by heating and drying at 130°C. . Then, the copper clad laminated body B-2 containing the polyimide resin layer of 25 micrometers in thickness was obtained through the 2nd heat treatment process of heating up and imidating from 160 degreeC to 360 degreeC. About the obtained copper clad laminated board B-2, copper foil was etched away using ferric chloride aqueous solution, and the multilayer polyimide film B-2 was prepared. The haze of this multilayer polyimide film B-2 was 78.67 %, and CTE was 23 ppm/K.

[Example 6]

14.49 parts by mass of m-TB (0.068 parts by mol), 1.11 parts by mass of TPE-Q (0.004 parts by mol), and 1.31 parts by mass of bisaniline-P (0.004 mol parts) in the reactor, and recycled DMF in an amount such that the solid content concentration after polymerization is 15% by weight /DMAc mixed solution 1 was added and stirred at room temperature to dissolve. Then, after adding 8.13 mass parts PMDA (0.037 mol part) and 10.97 mass parts BPDA (0.037 mol part), stirring was continued at room temperature for 3 hours, the polymerization reaction was carried out, and the polyamic-acid solution a-7 was obtained. The viscosity of the polyamic acid solution a-7 was 25,900 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 17,700 cps.

Next, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to one side of a long rolled copper foil (Rzjis = 0.88 μm) having a thickness of 18 μm and a width of 1,080 mm so that the thickness after curing was 2.5 μm. Then, the solvent was removed by heating and drying at 130°C. Next, the polyamic acid solution a-7 was uniformly coated on the dried polyamic acid solution c-1 to a thickness of 20 μm after curing, and then the solvent was removed by heating and drying at 130°C. Further, on the dried polyamic acid solution a-7, the polyamic acid solution c-1 prepared in Synthesis Example 4 was uniformly applied to a thickness of 2.5 μm after curing, and then the solvent was removed by heating at 130° C. . Then, the copper clad laminated body A-7 containing the polyimide resin layer of 25 micrometers in thickness was obtained through the 2nd heat processing process of heating up and imidating from 160 degreeC to 360 degreeC. With respect to the obtained copper clad laminated board A-7, copper foil was etched away using ferric chloride aqueous solution, and the multilayer polyimide film A-7 was prepared. The haze of this multilayer polyimide film A-7 was 63.87 %, and CTE was 21 ppm/K.

[Reference Example 1]

A polyamic acid solution a-8, a copper-clad laminate A-7, and a multilayer polyimide film A-8 were obtained in the same manner as in Example 1 except that the DMAc used was changed to the regenerated DMAc4.

The obtained polyamic acid solution a-7 had a viscosity of 21,900 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 9,100 cps. Moreover, the haze of the multilayer polyimide film A-8 was 59.55 %, and CTE was 23 ppm/K.

[Reference Example 2]

A polyamic acid solution b-3, a copper clad laminate B-3, and a multilayer polyimide film B-3 were obtained in the same manner as in Example 5 except that the DMAc used was changed to the regenerated DMAc4.

The obtained polyamic acid solution b-3 had a viscosity of 22,100 cps. Moreover, the viscosity when it preserve|saved for 20 days at 23 degreeC and 50 %RH was 9,800 cps. Moreover, the haze of the multilayer polyimide film B-3 was 72.22 %, and CTE was 24 ppm/K.

As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention can be variously modified without being limited to the said embodiment.

Claims (9)

The following components A and B;
A) an aprotic polar solvent having a boiling point of 200° C. or less under 1 atm;
B) water
contains, the content of the component A measured by gas chromatography is 50% or more, and the content of the component B measured by the Karl Fischer method is in the range of 40 to 500 ppm organic solvent. The organic solvent according to claim 1, wherein the component A is at least one selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide and dimethylsulfoxide. The organic solvent according to claim 1 or 2, which is a solvent used to obtain polyamic acid by mixing and polymerizing the tetracarboxylic anhydride component and the diamine component. The mixed solution containing the organic solvent in any one of Claims 1-3, a tetracarboxylic-acid anhydride component, and a diamine component. The mixed solution according to claim 4, wherein 50 mol% or more of a monomer having a biphenyl skeleton is contained in the total monomer components derived from the tetracarboxylic anhydride component and the diamine component. The mixed solution according to claim 4 or 5, wherein the diamine component contains 20 mol% or more of the diamine compound represented by the following general formula (1).

[In the general formula (1), the linking group Z represents a single bond or -COO-, and Y is independently a monovalent hydrocarbon group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen or phenyl group, or represents a perfluoroalkyl group or alkenyl group having 1 to 3 carbon atoms, n represents an integer of 1 to 2, and p and q independently represent an integer of 0 to 4.] The following steps a to d;
a) The process of preparing the mixed solution containing the organic solvent in any one of Claims 1-3, a tetracarboxylic-acid anhydride component, and a diamine component;
b) a step of reacting the tetracarboxylic anhydride component and the diamine component in the mixed solution to obtain a polyamic acid solution;
c) forming a resin film of the polyamic acid by applying the polyamic acid solution on a substrate and drying;
d) a step of heat-treating the resin film and imidizing the polyamic acid to obtain a polyimide film
A method for producing a polyimide film, comprising: The method for producing a polyimide film according to claim 7, wherein the organic solvent is recovered from the solvent vapor generated in the step c, and reused as the organic solvent of the mixed solution. The method for producing a polyimide film according to claim 7, wherein the organic solvent in the step a is obtained through the step of recovering the solvent vapor generated in the step c.