WO2018070398A1

WO2018070398A1 - Transparent polyimide resin, transparent polyimide resin composition, transparent polyimide resin film, infrared absorbing composition, infrared cut filter, and production method for transparent polyimide resin film

Info

Publication number: WO2018070398A1
Application number: PCT/JP2017/036735
Authority: WO
Inventors: 一成中原; 悠太郎堀江; 福坂　潔; 康敏伊藤
Original assignee: コニカミノルタ株式会社
Priority date: 2016-10-12
Filing date: 2017-10-11
Publication date: 2018-04-19
Also published as: JPWO2018070398A1; JP7036021B2

Abstract

The transparent polyimide resin according to the present invention is characterized in that at least one of the terminals of the polyimide has either a terminal group having an aromatic ring that has an NICS value falling within the range of -15.0 to -8.0 or a terminal group having two or more aromatic rings that have an NICS value falling within the range of -15.0 to -7.0.

Description

Transparent polyimide resin, transparent polyimide resin composition, transparent polyimide resin film, infrared absorbing composition, infrared cut filter, and method for producing transparent polyimide resin film

The present invention relates to a transparent polyimide resin, a transparent polyimide resin composition, a transparent polyimide resin film, an infrared absorbing composition, an infrared cut filter, and a method for producing a transparent polyimide resin film. More specifically, the transparency of the film is good and the mechanical strength is improved. It is related with the transparent polyimide resin etc. which were excellent in.

In recent years, with the widespread use of smartphones and tablet terminals, technology for further reducing the weight and thickness of these has become necessary, and polymer substrates that replace glass substrates have been demanded. In particular, a transparent substrate used for the outermost surface of the display is required to have strong mechanical strength and chemical stability such as scratch resistance, flexibility, impact resistance, and light resistance. In addition, with the widespread use of organic electroluminescence (EL) displays, foldable displays have been developed, and such displays are required to be transparent and have excellent bending resistance. In addition, transparent and flexible printed boards are required to have high mechanical strength (bending strength, elastic modulus, etc.) and heat resistance. Furthermore, high durability is required for in-vehicle films. Thus, a transparent film with high mechanical strength and high heat resistance is expected in many fields.

Polyimide has been developed as a glass replacement film in recent years due to its high mechanical strength and heat resistance.

However, conventional polyimides composed of aromatic rings (hereinafter also referred to as “totally aromatic polyimides”) have high mechanical strength and heat resistance, but charge transfer complexes (hereinafter also referred to as “CT complexes”) within and between molecules. The film is colored yellow to form a film, and cannot be used as a display film. Therefore, molecular design that suppresses the formation of intermolecular CT complexes and intramolecular CT complexes has been carried out.

As a method for suppressing intermolecular CT complexes, a method for inhibiting packing of molecular chains by introducing bulky substituents has been developed. However, in this method, since the interaction between the molecular chains is lowered, the mechanical strength is greatly reduced, so that the required strength cannot be imparted.

In addition, as a method of suppressing the generation of intramolecular CT complex, a method of suppressing the generation of CT complex by orthogonalizing the structures of the polyimide donor site and the acceptor site, a method of introducing an alicyclic monomer, A method for forming a cyclic structure and a method using a fluorine-based monomer have been developed.

However, although any method is effective for transparency, it has not yet been able to obtain the required mechanical strength because it is designed to weaken the interaction between molecules sterically or electronically.

In addition, there is a report of improving the mechanical strength by introducing a heat-crosslinkable substituent at the end of the polyimide that has been made transparent by the above method (see, for example, Patent Document 1).

However, in addition to insufficient mechanical strength required by this method, cross-linking results in polyimide that is insoluble in organic solvents, and reuses the cut film (returned material) at the end of the film that occurs during film production. It was difficult. That is, the cut product (returned material) is reused as part of the polyimide resin added in the production of the next lot, and when it is dissolved in an organic solvent to prepare a dope, it is reused because it is insoluble in the organic solvent. There was a problem that productivity was low because it was not possible.

On the other hand, in general, the polymer terminal has a large molecular mobility and affects the melting point, glass transition point, and thermal decomposition temperature. For example, by introducing an aromatic skeleton at the end of polylactic acid, the mobility at the molecular end is suppressed by the π-π interaction between the aromatic skeletons to improve the thermal decomposition temperature (non- (See Patent Document 1). In order to improve the mechanical strength of the resin in addition to heat resistance, it is effective to reduce the mobility of the entire polymer chain, so it is necessary to suppress not only the mobility of the polymer end but also the mobility of the main chain .

Patent Document 2 describes that during polyimide synthesis, the amount of carboxylic dianhydride units is increased and polymerized, and the terminal is made carboxylic anhydride to suppress coloring. However, the elastic modulus of the transparent polyimide having a carboxylic anhydride terminal described in this document is described as 1.0 to 3.0 GPa, which is insufficient for the required mechanical strength. If the terminal is a carboxylic acid anhydride, coloring by the amine can be suppressed, but since the carboxylic acid anhydride decomposes into a dicarboxylic acid structure, the terminal mobility is improved, and the elastic modulus and heat resistance are improved. It is not considered.

In the example of Patent Document 3, it is described that phthalic anhydride is modified at the amine terminal of a transparent polyimide. However, this patent document has no description about the effect of terminal modification on mechanical strength, and the mechanical strength and heat resistance required by the polyimide terminal-modified with phthalic anhydride described in Examples could not be imparted.

Therefore, there is a problem that it is difficult to obtain a transparent polyimide having good mechanical strength and heat resistance.

JP 2011-074384 A Japanese Patent Laid-Open No. 2015-021022 JP 2012-251080 A

The present invention has been made in view of the above-mentioned problems and situations, and a problem to be solved is to provide a transparent polyimide resin having good transparency and excellent mechanical strength (bending resistance, elastic modulus, etc.). Moreover, it is providing the transparent polyimide resin composition using a polyimide resin, a transparent polyimide resin film, an infrared rays absorption composition, and an infrared cut filter. Furthermore, it is providing the manufacturing method of a transparent polyimide resin film.

In the process of examining the cause of the above-mentioned problems in order to solve the above-mentioned problems according to the present invention, even if it is a transparent polyimide resin, by introducing a substituent having a specific aromaticity at the end of the polyimide, The inventors have found that the mechanical strength is improved, and have reached the present invention.

In addition, the transparent polyimide resin having aromaticity at the terminal has excellent solubility in a solvent (hereinafter also referred to as “re-solubility”) and is easy to produce a film by a solution casting method, and thus is excellent in productivity. I found.

That is, the problem according to the present invention is solved by the following means.

1. A transparent polyimide resin containing a polyimide having an aromatic moiety, wherein at least one of the ends of the polyimide has a terminal group having an aromatic ring having a NICS value in the range of -15.0 to -8.0, and A transparent polyimide resin having any group of terminal groups having two or more aromatic rings having a NICS value in the range of -15.0 to -7.0.

2. 2. The transparent polyimide resin according to item 1, wherein the polyimide is a polymer of an aromatic dicarboxylic acid anhydride and an aromatic diamine having a sterically hindering group at the ortho position of the amino group.

3. 3. The transparent polyimide resin according to item 1 or 2, wherein the polyimide is a polymer of an alicyclic dicarboxylic acid anhydride and an aromatic diamine.

4. Any one of Items 1 to 3, wherein the terminal group is a terminal group having one or more aromatic rings having a NICS value in the range of -15.0 to -10.0. The transparent polyimide resin as described in the item.

5. The said polyimide has the structure represented by following General formula (1) or General formula (2), The transparent polyimide resin as described in any one of 1st term | claim to 4th term | claim characterized by the above-mentioned.

(Wherein A and R each independently represents an aromatic ring, an aromatic heterocyclic ring, an aliphatic hydrocarbon group having 2 to 39 carbon atoms, or an alicyclic hydrocarbon group having 2 to 39 carbon atoms, A and R may be —O—, —SO ₂ —, —CO—, —CH ₂ —, —C (CH ₃ ) ₂ —, —OSi (CH ₃ ) ₂ —, A plurality of aromatic hydrocarbon rings, aromatic heterocycles, aliphatic hydrocarbon groups having 2 to 39 carbon atoms via at least one linking group of -C ₂ H ₄ O-, -S-, and a simple bond; Alternatively, an alicyclic hydrocarbon group may be linked, provided that at least one aromatic moiety is present in the structure represented by A or R. R ₁ to R ₈ are each independently a polyimide. Represents a terminal group, provided that at least one of R ₁ to R ₄ and at least one of R ₅ to R ₈ are N Two end groups having one or more aromatic rings having an ICS value in the range of -15.0 to -8.0, or two aromatic rings having an NICS value in the range of -15.0 to -7.0. It is a terminal group having two or more.)

6). In said general formula (1) or general formula (2), said A represents the following structure, The polyimide resin of Claim 5 characterized by the above-mentioned.

[The above structure is bonded to N in the general formula (1) and the general formula (2) in the * part. ]

7). In said general formula (1) or general formula (2), said R represents the following structure, The polyimide resin of Claim 5 or 6 characterized by the above-mentioned.

[The above structure is bonded to the carbonyl group in the imide group at the * moiety. ]

8. A transparent polyimide resin composition comprising the transparent polyimide resin according to any one of items 1 to 7.

9. A transparent polyimide resin film comprising the transparent polyimide resin according to any one of items 1 to 7.

10. An infrared ray absorbing composition comprising the transparent polyimide resin according to any one of items 1 to 7.

11. An infrared cut filter comprising the transparent polyimide resin according to any one of items 1 to 7.

12 A step of preparing a dope obtained by dissolving the transparent polyimide resin according to any one of items 1 to 7 in an organic solvent, and casting the dope on a support to form a film The manufacturing method of the transparent polyimide resin film characterized by including a process.

The above-mentioned means of the present invention can provide a transparent polyimide resin having good transparency and excellent mechanical strength. Moreover, the transparent polyimide resin composition using a transparent polyimide resin, a transparent polyimide resin film, an infrared rays absorption composition, and an infrared cut filter can be provided. Moreover, the manufacturing method of the said transparent polyimide resin film excellent in productivity can be provided.

The expression mechanism or action mechanism of the effect of the present invention is considered as follows.

In order to develop a transparent polyimide resin film that is transparent, high in mechanical strength, and excellent in re-dissolvable productivity, the present inventors have introduced substituents that can interact strongly between polymer ends and between the polymer ends and the main chain. It was thought that mechanical strength could be improved even if it was a transparent polyimide resin film by modifying.

As described above, the transparent polyimide is produced by a method of suppressing the generation of a CT complex by making the structure of the polyimide donor site and acceptor site orthogonal, a method of introducing an alicyclic monomer, a method of using a fluorine-based monomer, etc. Has been developed. In order to improve the mechanical strength of the transparent polyimide resin, it is necessary to give them an interaction that connects the ends and the ends and the main chain. The present inventors paid attention to π-π interaction and CH-π interaction as the interaction. The transparent polyimide that can use these interactions is a polyimide containing an aromatic moiety in the main chain, and it was thought that the mechanical strength could be improved by introducing a substituent having a specific aromaticity at the terminal. .

The present inventors examined the end of the transparent polyimide in accordance with the above idea, and introduced a specific aromatic substituent having no crosslinking group at the end of the transparent polyimide containing an aromatic skeleton in the main chain. As a result, a transparent polyimide resin having high mechanical strength could be obtained.

Also, since the ends are not cross-linked but interact by π-π interaction or CH-π interaction, it is considered that a highly productive film that can be re-dissolved can be obtained.

In the present invention, “polyimide” refers to a compound having a polyimide structure, “polyimide resin” refers to a resin containing the polyimide, and “polyimide resin film” refers to a film made from the polyimide resin.

The figure which showed typically an example of the dope preparation process, casting process, and drying process of the solution casting film forming method preferable for this invention

The transparent polyimide resin of the present invention has a terminal group having an aromatic ring having a NICS value in the range of -15.0 to -8.0 at least one end of the polyimide, and a NICS value of -15.0 to It has any group of terminal groups having two or more aromatic rings in the range of −7.0. This feature is a technical feature common to the claimed invention.

As an embodiment of the present invention, the polyimide is a polymer of an aromatic dicarboxylic acid anhydride and an aromatic diamine having a sterically hindered group at the ortho position of the amino group, a transparent polyimide resin, and a transparent It is preferable from the viewpoint of excellent transparency of the polyimide resin film.

The polyimide is preferably a polymer of an alicyclic dicarboxylic acid anhydride and an aromatic diamine from the viewpoint of excellent transparency of the transparent polyimide resin and the transparent polyimide resin film.

Further, the terminal group is preferably a terminal group having one or more aromatic rings having a NICS value in the range of −14.0 to −10.0 from the viewpoint of excellent mechanical strength of the transparent polyimide resin film. .

Moreover, it is preferable that the polyimide has a structure represented by the general formula (1) or the general formula (2) from the viewpoint of excellent re-solubility, and production by a solution casting method is possible, thereby improving productivity. Excellent. This effect is an effect that cannot be obtained with a polyimide resin having a crosslinkable group at the end of the polyimide.

The transparent polyimide resin composition of the present invention preferably contains the transparent polyimide resin of the present invention from the viewpoint of excellent transparency, mechanical strength, and heat resistance.

The transparent polyimide resin film of the present invention preferably contains the transparent polyimide resin of the present invention from the viewpoint of excellent mechanical strength, heat resistance, and productivity of the transparent polyimide resin film.

The method for producing the transparent polyimide resin film of the present invention includes a step of preparing a dope obtained by dissolving the transparent polyimide resin of the present invention in an organic solvent, and casting the dope on a support to form a film. It is preferable from a viewpoint which is excellent in productivity of a transparent polyimide resin film to include a process.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

<Outline of Transparent Polyimide Resin of the Present Invention>
The transparent polyimide resin of the present invention is a transparent polyimide resin containing a polyimide having an aromatic moiety, and has a NICS value in the range of −15.0 to −8.0 at at least one of the ends of the polyimide. It has a terminal group having an aromatic ring and any group of terminal groups having two or more aromatic rings having a NICS value in the range of -15.0 to -7.0.

In addition, the conventional transparent polyimide resin (for example, the transparent polyimide resin described in Patent Document 2) has a benzene ring at the terminal, and does not correspond to the terminal group having a specific NICS value according to the present invention.

<Polyimide>
The polyimide according to the present invention is a compound containing an imide bond in a repeating unit, and is preferably formed from diamine or a derivative thereof and an acid anhydride or a derivative thereof.

The polyimide according to the present invention is characterized in that it includes a structure that suppresses the CT complex between and within the polyimide. Thereby, coloring is improved and transparency is improved. In order to suppress intermolecular and intramolecular CT complexes, an aromatic diamine having an electron-withdrawing group, an aromatic diamine having a sterically hindered group at the ortho position, a monomer having a highly sterically hindered group, an alicyclic ring It is necessary to use a formula monomer or the like.

In addition, the polyimide according to the present invention is characterized by having an aromatic moiety in the main chain in order to provide desired performance. The aromatic part should just be introduce | transduced into any one of diamine or its derivative (s), and an acid anhydride or its derivative (s), and may be introduce | transduced into both structures.
In particular, the polyimide according to the present invention is preferably a polymer of an aromatic dicarboxylic acid anhydride and an aromatic diamine having a sterically hindered group at the ortho position of the amino group. The polyimide is preferably a polymer of an alicyclic dicarboxylic acid anhydride and an aromatic amine.

The terminal of the polyimide according to the present invention is substituted with a structure containing an aromatic ring having a NICS value of -15.0 to -8.0, or two or more aromatic rings having a NICS value of -15.0 to -7.0 are present. It is characterized by being substituted with the structure it contains. This suppresses the mobility of the resin by forming π-π interaction or CH-π interaction between the resin ends or the aromatic moiety contained in the main chain described above, so that the mechanical strength and heat resistance are reduced. improves.

The polyimide according to the present invention is substituted with a structure containing an aromatic ring having a NICS value of -15.0 to -8.0 on at least one of the terminals, or an aromatic ring having a NICS value of -15.0 to -7.0. As long as it is substituted with a structure containing 2 or more, and it is preferable that both ends are substituted.
The molecular weight of the polyimide in the present invention is preferably in the range of 30,000 to 500,000, more preferably in the range of 50,000 to 300,000, and in the range of 70,000 to 250,000. It is particularly preferred. If the molecular weight is 30,000 or more, the mechanical strength as a polymer is improved, and if it is 500,000 or less, the viscosity becomes an appropriate viscosity, so that the productivity of polyimide and polyimide film is excellent.

<Polyimide having a structure represented by General Formula (1) or General Formula (2)>
As the polyimide that can be used in the present invention, a polyimide having a repeating unit represented by the general formula (1) or the general formula (2) and a terminal structure is particularly preferable.

(Wherein A and R each independently represents an aromatic ring, an aromatic heterocyclic ring, an aliphatic hydrocarbon group having 2 to 39 carbon atoms, or an alicyclic hydrocarbon group having 2 to 39 carbon atoms, A and R may be —O—, —SO ₂ —, —CO—, —CH ₂ —, —C (CH ₃ ) ₂ —, —OSi (CH ₃ ) ₂ —, A plurality of aromatic hydrocarbon rings, aromatic heterocycles, aliphatic hydrocarbon groups having 2 to 39 carbon atoms via at least one linking group of -C ₂ H ₄ O-, -S-, and a simple bond; Alternatively, an alicyclic hydrocarbon group may be linked, provided that at least one aromatic moiety is present in the structure represented by A or R. R ₁ to R ₈ are each independently a polyimide. Represents a terminal group, provided that at least one of R ₁ to R ₄ and at least one of R ₅ to R ₈ are N Two end groups having one or more aromatic rings having an ICS value in the range of -15.0 to -8.0, or two aromatic rings having an NICS value in the range of -15.0 to -7.0. It is a terminal group having two or more.)
The A or R has at least one aromatic moiety in the structure, and has a partial structure that suppresses the intermolecular or intramolecular CT described above. The polyimide resin can be made transparent by having a partial structure that suppresses intermolecular or intramolecular CT in the structure represented by A or R. In the present invention, “having two or more aromatic rings” means that there are two or more 5-membered rings or 6-membered rings, and the condensed ring counts each ring individually. Therefore, in the present invention, the naphthalene ring is “two aromatic rings”.

As the aromatic hydrocarbon ring represented by A and R, for example, benzene ring, biphenyl ring, naphthalene ring, azulene ring, fluorene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, pyranthrene ring, Anthraanthrene rings and the like can be mentioned.

As the aromatic ring represented by A and R, a benzene ring, a biphenyl ring, a naphthalene ring and a pyrene ring are preferable, and a benzene ring, a biphenyl ring and a naphthalene ring are more preferable. By introducing these rings, the mechanical strength is improved.

Examples of the aromatic heterocycle represented by A and R include a silole ring, a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, and an oxadiazole ring. , Triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, azacarbazole ring (carbazole ring) Any one or more of the carbon atoms constituting the dibenzosilole ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or dibenzofuran ring. Is a nitrogen atom Substituted ring, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, quindrine ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphene Nodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene ring, thianthrene ring Phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring and the like.

As the aromatic heterocycle represented by A and R, a pyridine ring, a pyrimidine ring, a triazine ring, a benzimidazole ring and a quinazoline ring are preferable, and a pyridine ring, a pyrimidine ring and a triazine ring are more preferable. By introducing these heteroaromatic rings, mechanical strength, heat resistance, and transparency are improved.
Examples of the aliphatic hydrocarbon group having 4 to 39 carbon atoms represented by A and R include groups such as butane, octane and decane.

Examples of the alicyclic hydrocarbon group having 4 to 39 carbon atoms represented by A and R include, for example, cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.2] oct-7-ene, bicyclo [2 2.2] groups such as octane, dicyclohexylmethane, 3,6-dimethylcyclohexylmethane, 1,4-diphenylcyclohexane and the like.

Examples of the divalent aliphatic hydrocarbon group having 2 to 39 carbon atoms represented by A and R include, in addition to a linear or branched aliphatic hydrocarbon group having 2 to 39 carbon atoms, the following structural formula: And the group represented.

In the above structural formula, n represents the number of repeating units, preferably 1 to 5, and more preferably 1 to 3. X is an alkanediyl group having 1 to 3 carbon atoms, that is, a methylene group, an ethylene group, a trimethylene group, or a propane-1,2-diyl group, and a methylene group is preferable.

In the general formulas (1) and (2), A preferably has the following structure.

In addition, the said structure couple | bonds with N in General formula (1) and General formula (2) in * part.

Among them, A-4, A-7, A-8, A-9, A-11, A-15, A-13, A-17, A-18, A-21, A-22, A-23, Transparency is improved by containing A-24, A-25, AC-1, AC-3, AC-4, AC-7, AC-8, AC-9, AC-10, AC-11. Further preferred.

A-1, A-2, A-5, A-6, A-7, A-8, A-12, A-9, A-19, A-22, A-24, A-26, AC-3, AC-7, AC-10, and AC-11 are preferable because the mechanical strength is improved by improving the rigidity of the main chain.

In the general formula (1) and the general formula (2) in the present invention, R preferably has the following structure.

The above structure is bonded to the carbonyl group in the imide group at the * part.

Among these, B-1, B-4, B-5, B-6, B-9, B-10, and B-17 are more preferable from the viewpoint of improving transparency due to the effects of electronic effects and steric hindrance. .

B-1, B-4, B-5, B-6, B-9, B-14, B-15, B-16, and B-17 have high main chain rigidity and improved mechanical strength. Therefore, it is preferable.

In addition, it is preferable to contain B-6 and B-15 from the viewpoint of improving the light resistance to ultraviolet rays.

The substituent that can be substituted for A and R is not particularly limited, and examples thereof include a hydrogen atom, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (methyl group, ethyl group, n-propyl). Group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group etc.), alkenyl group (vinyl group, allyl group) Etc.), cycloalkenyl groups (2-cyclopenten-1-yl, 2-cyclohexen-1-yl groups, etc.), alkynyl groups (ethynyl group, propargyl group, etc.), aryl groups (phenyl group, p-tolyl group, naphthyl group) Etc.), heteroaryl group (2-pyrrole group, 2-furyl group, 2-thienyl group, pyrrole group, imidazolyl group) Oxazolyl group, thiazolyl group, benzimidazolyl group, benzoxazolyl group, 2-benzothiazolyl group, pyrazolinone group, pyridyl group, pyridinone group, 2-pyrimidinyl group), cyano group, hydroxy group, nitro group, carboxy group, alkoxy group (Methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group, etc.), aryloxy group (phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group) , 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.), acyl group (acetyl group, pivaloylbenzoyl group, etc.), acyloxy group (formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, Benzoyloxy group, p Methoxyphenylcarbonyloxy group, etc.), amino group (amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group, etc.), acylamino group (formylamino group, acetylamino group, pivaloylamino) Group, lauroylamino group, benzoylamino group, etc.), alkyl and arylsulfonylamino groups (methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenyl) Sulfonylamino group, etc.), mercapto group, alkylthio group (methylthio group, ethylthio group, n-hexadecylthio group, etc.), arylthio group (phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group, etc.), sulfa Moyl group (N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoylsulfamoyl group, N -(N'phenylcarbamoyl) sulfamoyl group, etc.), sulfo group, carbamoyl group (carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- ( Methylsulfonyl) carbamoyl group and the like. These groups may be further substituted with the same group.

The substituent substituted with A is preferably a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an amide group, an aryl group, or a perfluoroalkyl group. Transparency improves by containing these groups.

Any one of R ₁ to R ₄ or any one of R ₅ to R _{8 in} the general formula (1) and the general formula (2) has a NICS value in the range of −15.0 to −8.0. A terminal group having one or more aromatic rings, or a terminal group having two or more aromatic rings having a NICS value in the range of -15.0 to -7.0, The other group which does not have represents the group similar to the substituent which can be substituted by A and R in General formula (1) and General formula (2). A compound having an aromatic ring having a NICS value of less than −15.0 is substantially difficult to synthesize, or has a very low productivity because it introduces a complicated synthesis route by introducing a substituent.

Any one of R ₁ to R ₄ in the general formula (1) and any one of R ₅ to R ₈ in the general formula (2) is within a range of NICS values from −15.0 to −8.0. More preferably, it is a terminal group having one or more aromatic rings.

R ₁ and R ₃ in the general formula (1) and R ₅ and R ₇ in the general formula (2) both have one or more aromatic rings having a NICS value in the range of -15.0 to -8.0. Or a terminal group having two or more aromatic rings having a NICS value in the range of -15.0 to -7.0, both having a NICS value of -15.0 to -8.0. More preferably, it is a terminal group having one or more aromatic rings within the range.

Among the groups represented by R ₁ to R ₈ in the general formula (1) and the general formula (2), one or more aromatic rings having a NICS value in the range of −15.0 to −8.0 are included. A group that is not a terminal group and that is not a terminal group having two or more aromatic rings having a NICS value in the range of -15.0 to -7.0 is not particularly limited. This is the same group as the substituent that can be substituted for A and R in the general formula (2). R ₁ and R ₂ , R ₃ and R ₄ , R ₅ and R ₆ , and R ₇ and R ₈ may be condensed to form a ring.

Two end groups having one or more aromatic rings having a NICS value in the range of -15.0 to -8.0, or two aromatic rings having a NICS value in the range of -15.0 to -7.0. The NICS value of the terminal group having two or more is preferably −8.0 or less, more preferably −9.0 or less, and particularly preferably −10.0 or less. When the NICS value is in the above range, the mechanical strength is improved by strengthening the interaction between the terminal and the main chain or the terminals.

The end group of the polyimide represented by R ₁ to R ₈ in the general formula (1) and the general formula (2) preferably has the following structure.

In the above structure, the * part is bonded to the main chain part of the polyimide.

For example, when the CH / π interaction is formed using the CH group portion of the water-adsorbing resin and the π electrons of the additive, it is naturally better that the additive has a stronger π property. There is an index called NICS (nucleus-independent chemical shift) value as an example that directly represents the strength of the π property.

This NICS value is an index used for quantification of aromaticity by magnetic properties. If the ring is aromatic, the ring current effect strongly shields the center of the ring, and conversely if it is antiaromatic. Anti-shielding (J. Am. Chem. Soc. 1996, 118, 6317). Depending on the magnitude of the NICS value, it is possible to determine the strength of the ring current, that is, the degree of contribution of π electrons to the aromaticity of the ring. Specifically, it represents the chemical shift (calculated value) of a virtual lithium ion arranged directly in the center of the ring, and the larger the value, the stronger the π property.

Some reports have been made on the measured NICS values. For example, Canadian Journal of Chemistry. , 2004, 82, 50-69, and The Journal of Organic Chemistry. , 2000, 67, 1333-1338.

In the present invention, the NICS value was calculated using Gaussian 09 (Revision C.01, US Gaussian Software). Specifically, first, the structure was optimized using B3LYP (density functional method) as a calculation method and 6-31G * (a function obtained by adding a polarization function to a split valence basis set) as a basis function. Subsequently, using the optimized structure, a dummy atom is placed at the center of the ring for calculating the NICS value, and one point calculation is performed by the NMR shielding constant calculation method (GIAO) with the basis function 6-311 + G ** to which the dispersion function is added. A value obtained by multiplying the NMR shielding constant of the obtained dummy atom by -1 was defined as a NICS value.

Table 1 below shows the NICS values in typical ring structures described in the literature.

As described in Table 1 above, a 5-membered aromatic heterocyclic ring such as a pyrrole ring, a thiophene ring, or a furan ring has a larger NICS value than an aromatic hydrocarbon such as a benzene ring or a naphthalene ring. The use of such an aromatic five-membered ring is expected to enhance the CH / π interaction.

The intermolecular force contributed by π electrons includes π / π interaction in addition to CH / π interaction. The π / π interaction is an intermolecular force that acts between two aromatic rings. Since an aromatic ring has a high polarizability, it is an intermolecular force that greatly contributes to dispersion force (London dispersion force). For this reason, an aromatic ring having a wide π-conjugated system has a higher polarizability and is likely to interact with π / π. Benzene, which is a 6π-electron system, has the most stable structure when one benzene ring is placed perpendicular to one benzene ring and a benzene ring and a hydrogen atom interact with each other. Naphthalene (10π electrons) and anthracene (14π electrons) with a wide system are most stable when the aromatic rings are stacked by π / π interaction. Is strong.

Also, the NICS value can be controlled by a substituent substituted on the ring, and when the electron donating group is substituted, the NICS value becomes negative and when the electron withdrawing group is substituted, the NICS value tends to become positive.

Aromatic, aliphatic or alicyclic tetracarboxylic acids or their derivatives may be used alone or in combination of two or more. Further, other tetracarboxylic acids or derivatives thereof (particularly dianhydrides) may be used in combination as long as they do not impair the solvent solubility of polyimide, the flexibility of the transparent polyimide resin film, the thermocompression bonding property, and the transparency.

Examples of such other tetracarboxylic acids or derivatives thereof include pyromellitic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 2, 2-bis (3,4-dicarboxyphenyl) propane, 2,2-bis (2,3-dicarboxyphenyl) propane, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1 , 3,3,3-hexafluoropropane, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane, bis (3,4-dicarboxy) Phenyl) sulfone, bis (3,4-dicarboxyphenyl) ether, bis (2,3-dicarboxyphenyl) ether, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 2,2 ′ 3,3′-benzophenonetetracarboxylic acid, 4,4- (p-phenylenedioxy) diphthalic acid, 4,4- (m-phenylenedioxy) diphthalic acid, 1,1-bis (2,3-dicarboxyl) Aromatic tetracarboxylic acids such as phenyl) ethane, bis (2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane and their derivatives (especially dianhydrides); ethylenetetracarboxylic acid Examples thereof include aliphatic tetracarboxylic acids having 1 to 3 carbon atoms and derivatives thereof (particularly dianhydrides).

As the acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride or biphenyltetracarboxylic dianhydride is excellent in transparency and heat due to heat shrinkage. This is preferable from the viewpoint of easy correction.

The repeating unit represented by the formula (1.1) is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, still more preferably 80 to 100 mol%, particularly preferably all the repeating units. Is 90 to 100 mol%. The number of repeating units of formula (1.1) in one molecule of polyimide (A) is 10 to 2000, preferably 20 to 200, and further within this range, the glass transition temperature is 230 to 350 ° C. The temperature is preferably 250 to 330 ° C.

Next, the polyimide synthesis method according to the present invention will be described.

<Polyamide acid synthesis method and imidization>
(Synthesis of polyamic acid)
The polyamic acid can be obtained by polymerizing at least one of the tetracarboxylic acids and at least one of the diamines in a suitable solvent.

The polyamic acid ester is diesterified by ring-opening the tetracarboxylic dianhydride with an alcohol such as methanol, ethanol, isopropanol, or n-propanol, and the obtained diester is converted into the above-mentioned diester in an appropriate solvent. It can be obtained by reacting with a diamine compound. Furthermore, the polyamic acid ester can also be obtained by esterification by reacting the carboxylic acid group of the polyamic acid obtained as described above with an alcohol as described above.

The reaction between the tetracarboxylic dianhydride and the diamine compound can be carried out under conventionally known conditions. There are no particular limitations on the order of addition or addition method of the tetracarboxylic dianhydride and the diamine compound. For example, a polycarboxylic acid can be obtained by sequentially adding a tetracarboxylic dianhydride and a diamine compound to a solvent and stirring at an appropriate temperature.

The amount of the diamine compound is usually 0.8 mol or more, preferably 1 mol or more with respect to 1 mol of tetracarboxylic dianhydride. On the other hand, it is 1.2 mol or less normally, Preferably it is 1.1 mol or less. The yield of the polyamic acid obtained can be improved by making the quantity of a diamine compound into such a range.

The concentration of tetracarboxylic dianhydride and diamine compound in the solvent is appropriately set according to the reaction conditions and the viscosity of the polyamic acid solution. For example, the total mass of the tetracarboxylic dianhydride and the diamine compound is not particularly limited, but is usually 1% by mass or more, preferably 5% by mass or more with respect to the total amount of the solution, while usually 70%. It is not more than mass%, preferably not more than 30 mass%. By setting the amount of the reaction substrate in such a range, the polyamic acid can be obtained at a low cost and in a high yield.

The reaction temperature is not particularly limited, but is usually 0 ° C. or higher, preferably 20 ° C. or higher, and is usually 100 ° C. or lower, preferably 80 ° C. or lower. The reaction time is not particularly limited but is usually 1 hour or longer, preferably 2 hours or longer, and is usually 100 hours or shorter, preferably 24 hours or shorter. By performing the reaction under such conditions, the polyamic acid can be obtained at a low cost and in a high yield.

Examples of the polymerization solvent used in this reaction include hydrocarbon solvents such as hexane, cyclohexane, heptane, benzene, toluene, xylene and mesitylene; carbon tetrachloride, dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and dichlorobenzene. And halogenated hydrocarbon solvents such as fluorobenzene; ether solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane and methoxybenzene; ketone solvents such as acetone and methyl ethyl ketone; N, N-dimethylformamide, N, N— Amide solvents such as dimethylacetamide and N-methyl-2-pyrrolidone; aprotic polar solvents such as dimethyl sulfoxide and γ-butyrolactone; pyridine, picoline, lutidine, quinoline and isoquinoline Ring-based solvents; phenols and phenolic solvents such as cresol, but and the like, but is not particularly limited. As a polymerization solvent, only 1 type can also be used and 2 or more types of solvents can also be mixed and used.

As the terminal group of the polyamic acid, an acid anhydride group or an amino group can be arbitrarily selected by using either one of a tetracarboxylic dianhydride and a diamine compound in excess during the polymerization reaction.

When the terminal group is an acid anhydride terminal, the terminal may be sealed with a monofunctional amine compound or isocyanate compound. The amine compound or isocyanate compound used here is not particularly limited as long as it is a monofunctional primary amine compound or isocyanate compound. For example, aniline, methylaniline, dimethylaniline, trimethylaniline, ethylaniline, diethylaniline, triethylaniline, aminophenol, methoxyaniline, aminobenzoic acid, biphenylamine, naphthylamine, cyclohexylamine, phenyl isocyanate, xylylene isocyanate, cyclohexyl isocyanate , Methylphenyl isocyanate, trifluoromethylphenyl isocyanate, and the like.

Further, when the terminal group is an amine terminal, for example, 4-ethynylphthalic anhydride, methylphthalic anhydride, dimethylphthalic anhydride, trimellitic anhydride, naphthalenedicarboxylic anhydride, etc. Can do. Also, amides may be formed by reaction with monocarboxylic acid anhydrides or acid chlorides, such as p-methoxybenzoic anhydride, naphthalenecarboxylic acid chloride, 4-acetoxybenzoic acid chloride, thiophene-2-carbonyl chloride, etc. Can be raised.

(Imidation method)
Here, the polyimide is a method in which the polyamic acid solution is heated to imidize the polyamic acid (thermal imidization method), or a polycyclic acid (imidation catalyst) is added to the polyamic acid solution to imidize the polyamic acid. It can be obtained by a method (chemical imidization method).

Also, a method of imidizing polyamic acid by heating the polyamic acid solution (thermal imidization method), or a method of imidizing polyamic acid by adding a ring-closing catalyst (imidation catalyst) to the polyamic acid solution (chemical imide) As for the conversion method), a reaction vessel for polymerizing polyamic acid from an acid anhydride and a diamine may be continued as it is and imidized in the reaction vessel.

In the thermal imidization method in the reaction kettle, the polyamic acid in the polymerization solvent is heated for, for example, 80 to 300 ° C. for 0.1 to 200 hours to advance imidization. Further, the temperature range is preferably 150 to 200 ° C., and by setting the temperature range to 150 ° C. or higher, imidization can be reliably progressed and completed. It is possible to prevent an increase in the resin concentration due to oxidation of unreacted raw materials and volatilization of the solvent.

Further, in the thermal imidization method, an azeotropic solvent can be added to the polymerization solvent in order to efficiently remove water generated by the imidization reaction. As the azeotropic solvent, for example, aromatic hydrocarbons such as toluene, xylene and solvent naphtha, and alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and dimethylcyclohexane can be used. When an azeotropic solvent is used, the amount added is about 1 to 30% by mass, preferably 5 to 20% by mass, based on the total amount of organic solvent.

On the other hand, in the chemical imidization method, a known ring closure catalyst is added to the polyamic acid in the polymerization solvent to advance imidization. Specific examples of the ring-closing catalyst include aliphatic tertiary amines such as trimethylamine and triethylenediamine, and heterocyclic tertiary amines such as isoquinoline, pyridine and picoline. Examples thereof include substituted nitrogen-containing heterocyclic compounds, N-oxide compounds of nitrogen-containing heterocyclic compounds, substituted or unsubstituted amino acid compounds, aromatic hydrocarbon compounds having an hydroxy group, or aromatic heterocyclic compounds. -Lower alkyl imidazole such as dimethylimidazole, N-methylimidazole, N-benzyl-2-methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 5-methylbenzimidazole, N-benzyl-2-methyl Imidazole derivatives such as imidazole, isoquinoline, 3 A substituted pyridine such as 5-dimethylpyridine, 3,4-dimethylpyridine, 2,5-dimethylpyridine, 2,4-dimethylpyridine, 4-n-propylpyridine, p-toluenesulfonic acid, etc. can be preferably used. it can. The addition amount of the ring closure catalyst is preferably about 0.01 to 2 times equivalent, particularly about 0.02 to 1 time equivalent to the amic acid unit of the polyamic acid. By using a ring-closing catalyst, the properties of the resulting polyimide, particularly elongation and breaking resistance, may be improved.

In the thermal imidization method or chemical imidization method, a dehydrating agent may be added to the polyamic acid solution. Examples of such a dehydrating agent include aliphatic acid anhydrides such as acetic anhydride, phthalates, and the like. Examples thereof include aromatic acid anhydrides such as acid anhydrides, and these can be used alone or in combination. In addition, it is preferable to use a dehydrating agent because the reaction can proceed at a low temperature. Although it is possible to imidize polyamic acid only by adding a dehydrating agent to the polyamic acid solution, it is preferable to imidize by heating or addition of a ring-closing catalyst as described above because the reaction rate is slow. .

Thus, the polyimide solution imidized in the reaction kettle is advantageous because it is less likely to cause a decrease in molecular weight due to hydrolysis over time than the polyimide solution.
Further, since the imidization reaction has progressed in advance, for example, in the case of a polyimide having an imidization rate of 100%, imidization on the cast film is unnecessary, and the drying temperature can be lowered.

Alternatively, the ring-closed polyimide may be reprecipitated using a poor solvent or the like, purified to a solid, dissolved in a solvent, and cast and dried to form a film.

According to this method, it is possible to make the polymerization solvent and the solvent to be cast different from each other, and it is possible to draw out the performance of the transparent polyimide resin film by selecting an optimum solvent for each.

For example, in order to increase the molecular weight of polyamic acid, it is polymerized and cyclized with dimethylacetamide, solidified with methanol, dried, then made into a solution containing an additive with dichloromethane, then cast and dried. Thus, high molecular weight and low temperature drying are possible.

Also, when dichloromethane is used as a solvent, it can be used in combination with other solvents. A co-solvent such as tetrahydrofuran (THF), dioxolane, cyclohexanone, cyclopentanone, γ-butyrolactone, ethanol, methanol, butanol, ilopropanol can be used as appropriate.

The higher the imidization rate, the more preferable upper limit is 100%. The polyamideimide resin can be synthesized by a usual method. For example, an isocyanate method, an amine method (acid chloride method, low temperature solution polymerization method, room temperature solution polymerization method, etc.), etc., but the polyamideimide resin used in the present invention is preferably soluble in an organic solvent, as described above. For reasons such as ensuring the reliability of peel strength (adhesive strength), production by the isocyanate method is preferred. Also, industrially, it is preferable because the solution at the time of polymerization can be applied as it is.

<Physical properties of transparent polyimide resin>
(Total light transmittance)
The polyimide resin of the present invention is a transparent polyimide resin. In the present invention, the transparent polyimide resin means a polyimide resin having a total light transmittance of 80% or more when a polyimide film having a thickness of 40 μm is produced from the polyimide resin.

The total light transmittance is more preferably 85% or more, and still more preferably 90% or more. A higher total light transmittance is preferable because transparency increases. The description of the numerical value that the total light transmittance is 80% or more shows the preferable range.

The total light transmittance of the transparent polyimide resin film can be measured according to JIS K 7375-2008 for one transparent polyimide resin film sample conditioned for 24 hours in an air conditioning room at 23 ° C. and 55% RH. The measurement can measure the transmittance in the visible light region (range of 400 to 700 nm) using a spectrophotometer U-3300 manufactured by Hitachi High-Technologies Corporation.

全 To make the total light transmittance 80% or more, it can be adjusted by selecting the type of polyimide.

(Yellow index value (YI value))
The transparent polyimide resin of the present invention is preferably a colorless transparent polyimide resin. As a measure of being colorless, it is preferable that a yellow index value (YI value) when a transparent polyimide resin film having a thickness of 40 μm is made of the transparent polyimide resin is 5.0 or less. More preferably, it is in the range of 0.3 to 2.0, and particularly preferably in the range of 0.3 to 1.6. A smaller yellow index value (YI value) is preferable because coloring is less. The description of the numerical value that the yellow index value (YI value) is 5.0 or less indicates the preferable range.

The YI value can be adjusted by selecting the type of polyimide.

The yellow index value can be obtained according to the YI (yellow index: yellowness index) of the film defined in JIS K 7103.

The yellow index value is measured by preparing a film sample and using a spectrophotometer U-3300 manufactured by Hitachi High-Technologies Corporation and the attached saturation calculation program, etc., as a light source specified in JIS Z 8701. The tristimulus values X, Y and Z of the color are obtained, and the yellow index value is obtained according to the definition of the following formula.

Yellow index (YI) = 100 (1.28X-1.06Z) / Y
(Solubility of transparent polyimide resin in dichloromethane)
The transparent polyimide resin of the present invention preferably has a limit amount (solubility) that dissolves in 100 g of dichloromethane at 25 ° C. from the viewpoint of producing a film with high productivity by the solution casting method. If the solubility is 1 g or more, it can be easily produced by the solution casting method. When the solubility is 50 g or more, it is difficult to form a film at the time of casting the solution, and film formation becomes difficult.

The solubility of the polyimide according to the present invention can be adjusted by selecting the type of polyimide used in the present invention.

In order to make polyimides soluble, it is effective to reduce the ratio of the structure of imide groups and aromatic hydrocarbons that work in the direction of increasing the planarity of the molecular skeleton of polyimide. It is also effective to introduce structural isomers, bending groups, aliphatic groups or alicyclic groups instead of aromatic groups, and bulky skeletons such as fluorine atoms and fluorenes.

Examples of compounds include alicyclic, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,3,4, 5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, (bicyclo [4.2.0] octane -3,4,7,8-tetracarboxylic dianhydride) bicyclo [2.2.1] heptanedimethanamine, the structure having a bending group is 2,3 ', 3,4'-biphenyltetracarboxylic Acid dianhydride, 3,4'-oxydiphthalic anhydride, 4,4 'oxydiphthalic anhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride, 3,3 ', 4,4 ′ -Difeni Sulfonetetracarboxylic dianhydride, 2,2-bis (4- (3,4-dicarboxyphenoxy) phenyl) propane dianhydride, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2- Bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) ) Benzene, bis (3-aminophenyl) sulfone, 3,3'-diaminobenzophenone, 3,4'-diaminodiphenyl ether.

Examples of the compound containing a fluorine atom include 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, 2,2'-bis (trifluoromethyl) benzidine, 2,2-bis (3-amino-4 -Hydroxyphenyl) hexafluoropropane, compounds containing a fluorene group include 9,9-bis (4-amino-3-fluorophenyl) fluorene, 9,9-bis [4- (3,4-dicarboxyphenoxy) ) -Phenyl] fluorene anhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -phenyl] fluorene anhydride, 9,9-Bis (3,4-dicboxyphenyl) fluorene Pilot fluorene Dianhydride It is done.

<Transparent polyimide resin composition>
Various resins, additives and solvents can be mixed into the transparent polyimide resin of the present invention to obtain a transparent polyimide resin composition. As a preferable course of the transparent polyimide resin composition of the present invention, it can be used as a material for a resin molded product or the like, in addition to a manufacturing material such as a transparent polyimide resin film described below.

<Transparent polyimide resin film>
A transparent polyimide resin film can be obtained using the above-described transparent polyimide resin and transparent polyimide resin composition of the present invention.

(Additive)
It is preferable that the following additives are mixed in the transparent polyimide resin film of the present invention.

(Mechanical strength modifier)
In order to improve the mechanical strength, the transparent polyimide resin film of the present invention can contain a mechanical strength modifier. Since the transparent polyimide resin in the present invention contains an aromatic ring in the main chain and has an aromatic ring having a specific NICS value at the polymer terminal, a compound having an aromatic ring is preferable from the viewpoint of improving mechanical strength. It is more preferable to add a compound containing two or more compounds or a compound containing a heteroaromatic ring, and a compound containing two or more aromatic rings or a nitrogen-containing aromatic heterocyclic compound is particularly preferable.

Examples of the preferable compound include compounds represented by general formula (1) and general formula (2) described in International Publication No. 2014/109350, compounds containing a 1,3,5-triazine skeleton, Examples thereof include compounds containing a 3-pyrimidine skeleton and polyesters containing an aromatic ring described in paragraph [0040] of JP2013-232005.

(Matting agent)
In order to improve the handleability, the transparent polyimide resin film of the present invention has, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, silicic acid. It is preferable to include a matting agent such as inorganic fine particles such as aluminum, magnesium silicate and calcium phosphate, and a crosslinked polymer. Of these, silicon dioxide is preferable because it can reduce the haze of the film.

The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm.

These fine particles preferably form secondary particles having a particle size of 0.1 to 5 μm and are contained in the polyimide. A preferable average particle size is 0.1 to 2 μm, and more preferably 0.2 to 0.00. 6 μm. As a result, irregularities having a height of about 0.1 to 1.0 μm are formed on the film surface, thereby providing appropriate slipperiness to the film surface.

The primary average particle diameter of the fine particles used in the present invention is measured by observing the particles with a transmission electron microscope (magnification of 500,000 to 2,000,000 times), observing 100 particles, measuring the particle diameter, and measuring the average. Let the value be the primary average particle size.

(UV absorber)
The transparent polyimide resin film of the present invention preferably contains an ultraviolet absorber from the viewpoint of improving light resistance. The ultraviolet absorber is intended to improve light resistance by absorbing ultraviolet rays of 400 nm or less, and the transmittance at a wavelength of 370 nm is preferably in the range of 0.1 to 30%, more preferably. Is in the range of 1-20%, more preferably in the range of 2-10%.

The UV absorbers preferably used in the present invention are benzotriazole UV absorbers, benzophenone UV absorbers, and triazine UV absorbers, and particularly preferably benzotriazole UV absorbers and benzophenone UV absorbers.

For example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6- (linear and side Chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, etc., and tinuvin 109, tinuvin 171, tinuvin 234, tinuvin 326, tinuvin 327, tinuvin 328, There are tinuvins (registered trademark) such as tinuvin 928, and these are all commercially available products manufactured by BASF Japan Ltd. and can be preferably used. Of these, halogen-free ones are preferred.

In addition, a discotic compound such as a compound having a 1,3,5-triazine ring is also preferably used as the ultraviolet absorber.

The transparent polyimide resin film of the present invention preferably contains two or more kinds of ultraviolet absorbers.

Also, as the ultraviolet absorber, a polymeric ultraviolet absorber can be preferably used, and in particular, a polymer type ultraviolet absorber described in JP-A-6-148430 is preferably used. Moreover, it is preferable that the ultraviolet absorber does not have a halogen group.

The method of adding the UV absorber is to add the dope after dissolving the UV absorber in an alcohol such as methanol, ethanol, butanol, an organic solvent such as dichloromethane, methyl acetate, acetone, dioxolane, or a mixed solvent thereof, or You may add directly in dope composition.

For inorganic powders that do not dissolve in organic solvents, use a dissolver or sand mill in the organic solvent and transparent polyimide resin film to disperse them before adding them to the dope.

The amount of UV absorber used is not uniform depending on the type of UV absorber, usage conditions, etc., but when the dry film thickness of the transparent polyimide resin film is 15 to 50 μm, it is 0.5% relative to the transparent polyimide resin film. The range of ˜10% by mass is preferred, and the range of 0.6˜4% by mass is more preferred.

(Antioxidant)
Antioxidants are also referred to as deterioration inhibitors. When an electronic device or the like is placed in a high humidity and high temperature state, the transparent polyimide resin film may be deteriorated.

The antioxidant has a role of delaying or preventing the transparent polyimide resin film from being decomposed by, for example, the residual solvent amount of halogen in the transparent polyimide resin film or phosphoric acid of the phosphoric acid plasticizer. It is preferable to make it contain in the transparent polyimide resin film of invention.

As such an antioxidant, a hindered phenol compound is preferably used. For example, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di- -T-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3 -(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino)- 1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], oct Decyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxy Benzyl) -isocyanurate and the like.

In particular, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3 -(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di- A phosphorus processing stabilizer such as t-butylphenyl) phosphite may be used in combination.

The amount of these compounds added is preferably in the range of 1 ppm to 1.0% by mass relative to the transparent polyimide resin film, and more preferably in the range of 10 to 1000 ppm.

(Phase difference control agent)
In order to improve the display quality of image display devices such as liquid crystal display devices, a retardation control agent is added to the transparent polyimide resin film, or an alignment film is formed to provide a liquid crystal layer, derived from a polarizing plate protective film and a liquid crystal layer By compounding the above phase difference, optical compensation ability can be imparted to the transparent polyimide resin film.

Examples of the retardation control agent include aromatic compounds having two or more aromatic rings as described in European Patent No. 91656A2, and rod-like compounds described in JP-A-2006-2025. Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound is preferably an aromatic heterocyclic ring including an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring. The aromatic heterocycle is generally an unsaturated heterocycle. Of these, the 1,3,5-triazine ring described in JP-A-2006-2026 is preferable.

In addition, the compound having the structure represented by the general formula (A1) also functions as a phase difference controlling agent. For this reason, the compound which has a structure represented by general formula (A1) can provide both the function of both phase difference control and optical value fluctuation | variation suppression with respect to temperature / humidity environmental fluctuation | variation with one compound.

The amount of these retardation control agents added is preferably in the range of 0.5 to 20% by mass, preferably in the range of 1 to 10% by mass with respect to 100% by mass of the transparent polyimide resin film resin. It is more preferable.

(Peeling accelerator)
As additives for reducing the peeling resistance of transparent polyimide resin films, there are many remarkable effects on surfactants, and preferable release agents include phosphate ester type surfactants, carboxylic acid or carboxylate type surfactants. Agents, sulfonic acid or sulfonate surfactants, and sulfate ester surfactants are effective. A fluorine-based surfactant in which part of the hydrogen atoms bonded to the hydrocarbon chain of the surfactant is substituted with fluorine atoms is also effective. Examples of the release agent are given below.
RZ-1 C ₈ H ₁₇ O—P (═O) — (OH) ₂
RZ-2 C ₁₂ H ₂₅ O—P (═O) — (OK) ₂
RZ-3 C ₁₂ H ₂₅ OCH ₂ CH ₂ O—P (═O) — (OK) ₂
RZ-4 C ₁₅ H ₃₁ (OCH ₂ CH ₂ ) ₅ O—P (═O) — (OK) ₂
_{_{_{RZ-5 {C 12 H 25}}} O (CH 2 CH 2 O) 5} 2 -P (= O) -OH
RZ-6 {C ₁₈ H ₃₅ (OCH ₂ CH ₂ ) ₈ O} ₂ —P (═O) —ONH ₄
RZ-7 (tC ₄ H ₉ ) ₃ —C ₆ H ₂ —OCH ₂ CH ₂ O—P (═O) — (OK) ₂ RZ-8 (iso-C ₉ H ₁₉ —C ₆ H ₄ — O— (CH ₂ CH ₂ O) ₅ —P (═O) — (OK) (OH)
RZ-9 C ₁₂ H ₂₅ SO ₃ Na
RZ-10 C ₁₂ H ₂₅ OSO ₃ Na
RZ-11 C ₁₇ H ₃₃ COOH
RZ-12 C ₁₇ H ₃₃ COOH · N (CH ₂ CH ₂ OH) ₃
RZ-13 iso-C ₈ H ₁₇ —C ₆ H ₄ —O— (CH ₂ CH ₂ O) ₃ — (CH ₂ ) ₂ SO ₃ Na
_{_{_{RZ-14 (iso-C 9}}} H 19) 2 -C 6 H 3 -O- (CH 2 CH 2 O) 3 - (CH 2) 4 SO 3 Na
RZ-15 sodium triisopropyl naphthalene sulfonate RZ-16 sodium tri-t-butyl naphthalene sulfonate RZ-17 C ₁₇ H ₃₃ CON (CH ₃ ) CH ₂ CH ₂ SO ₃ Na
RZ-18 C ₁₂ H ₂₅ -C ₆ H ₄ SO ₃ .NH ₄
The addition amount of the peeling accelerator is preferably 0.05 to 5% by mass, more preferably 0.1 to 2% by mass, and most preferably 0.1 to 0.5% by mass with respect to the cyclic polyimide.

The additive contained in the transparent polyimide resin film of the present invention is not limited to the fine particles.

The transparent polyimide resin composition and transparent polyimide resin film of the present invention can contain a dye having absorption in the visible to infrared. By adding a dye having absorption in the visible range, for example, it can be used for a specific wavelength cut film or the like that can control the wavelength of the display light source and expand the color range. Moreover, the pigment | dye which has absorption in an infrared region can be used for the infrared cut film for sensors, for example. By adding these dyes, it becomes possible to adjust to a desired transmittance.
There is no particular limitation on the dye having absorption in the visible to infrared, and an organic dye or an inorganic dye can be used. Examples of organic dyes include phthalocyanine dyes, azo dyes, oxocarbon dyes, cyanine dyes, Ni complex dyes, and the like.
From the viewpoint of heat resistance and sharpness of absorption, the organic dye is preferably a phthalocyanine dye, an oxocarbon dye, a cyanine dye, or a Ni complex dye, and more preferably an oxocarbon dye. Examples of the inorganic dye include metal oxide fine particles and copper complex compounds.
Preferred inorganic dyes include tungsten oxide fine particles, indium oxide fine particles, and copper complex fine particles having phosphonic acid as a ligand, and copper complex fine particles having phosphonic acid as a ligand are more preferable.
The copper complex fine particles used in the present invention are preferably copper complex fine particles containing phosphonic acid and copper ions described in JP-A-2002-006101, and alkylphosphonic acids having 2 to 6 carbon atoms and copper ions. Particularly preferred are copper complex-based fine particles containing.
The dye having visible to infrared absorption used in the transparent polyimide resin composition and transparent polyimide resin film of the present invention may be dissolved in the resin or dispersed as fine particles.
The addition amount of the dye having absorption in the visible to infrared region used in the transparent polyimide resin composition and the transparent polyimide resin film of the present invention is not particularly limited, but is preferably in the range of 0.01 to 80% by mass. A range of 05 to 50% by mass is further preferable, and a range of 0.1 to 30% by mass is particularly preferable. It can adjust to a desired transmittance | permeability by adjusting to these ranges. The addition of 0.01% by mass or more makes it possible to control the transmittance. By setting the content within 35% by mass, bleeding out, dye aggregation, and fine particle aggregation are suppressed, and transparency is improved.

(Physical properties of transparent polyimide resin film)
The transparent polyimide resin film of the present invention preferably has the above-described total light transmittance and YI value, but other preferable physical property values include the following physical property values.

(Elastic modulus)
The tensile modulus can be measured by the following method according to JIS K7127.
1) A film is cut out to a size of 100 mm (MD direction) × 10 mm (TD axis) to obtain a test piece. Using a Tensilon RTC-1225A manufactured by Orientec Co., the distance between chucks is 50 mm, the test piece is pulled in the longitudinal direction (MD direction) of the test piece, and the tensile elastic modulus in the MD direction is measured. The measurement can be performed at 23 ° C. and 55% RH.
2) Similarly, the film is cut into a size of 100 mm (TD direction) × 10 mm (MD direction) to obtain a test piece. The test piece is pulled in the length direction (TD direction) in the same manner as described above, and the tensile elastic modulus in the TD direction is measured.
3) The average value of the tensile elastic modulus in the MD direction and the TD direction obtained in 1) and 2) is calculated.

From the viewpoint of the mechanical strength of the transparent polyimide resin film, the tensile elastic modulus of the transparent polyimide resin film is preferably 4 GPa or more, and more preferably 5 GPa or more.

(Haze value)
In this invention, about the transparent polyimide resin film of the roll body after heat processing, it is preferable from a viewpoint that the transparency of a transparent polyimide resin film is that a haze value is 4% or less.

The haze can be measured according to JIS K 7136 using a haze meter NDH-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). Measured under the conditions of 23 ° C. and 55% RH, the light source of the haze meter is a halogen bulb of 5V9W, and the light receiving part is a silicon photocell (with a relative visibility filter).

<Method for producing transparent polyimide resin film>
The specific example of the manufacturing method of the said transparent polyimide resin film is demonstrated below.

The method for producing a transparent polyimide resin film of the present invention includes a step of preparing a dope obtained by dissolving the transparent polyimide resin of the present invention in an organic solvent, and a step of casting the dope on a support to form a film. including.

The method for producing the transparent polyimide resin film of the present invention includes a step of preparing a dope obtained by dissolving the transparent polyimide resin of the present invention in an organic solvent (dope preparation step), and casting the dope on a support. Forming a film (casting film forming process), peeling the film from the support (peeling process), drying the obtained cast film to obtain a film (first drying process), drying A step of stretching the formed film (stretching step), a step of further drying the stretched film (second drying step), a step of winding up the obtained transparent polyimide resin film (winding step), and if necessary It is more preferable to include a step of heating the film to imidize (heating step) and the like.

The above process will be described with reference to the drawings.

FIG. 1 is a diagram schematically showing an example of a dope preparation step, a casting step, a drying step, and a winding step of a solution casting film forming method preferable for the present invention.

The fine particle dispersion in which the solvent and the matting agent are dispersed by the disperser passes from the charging tank 141 through the filter 144 and is stocked in the stock tank 142. On the other hand, the cycloolefin resin as the main dope is dissolved in the dissolving pot 101 together with the solvent, and a matting agent stored in the stock pot 142 is appropriately added and mixed to form the main dope. The obtained main dope is filtered from the filter 103 and the stock kettle 104 by the filter 106, the additive is added by the merge pipe 120, mixed by the mixer 121, and fed to the pressure die 130.

On the other hand, additives (for example, UV absorbers, antioxidants, etc.) are dissolved in a solvent, passed from the additive charging pot 110 through the filter 112 and stocked in the stock pot 113. After that, the main dope is mixed by the merging pipe 120 and the mixer 121 through the filter 115 and the conduit 116.

The main dope fed to the pressure die 130 is cast on a metal belt-like support 131 to form a web 132, and peeled at a peeling position 133 after predetermined drying to obtain a film. The peeled web 132 is dried until it reaches a predetermined residual solvent amount while passing through a large number of conveying rollers in the first drying device 134 and then stretched in the longitudinal direction or the width direction by the stretching device 135. After stretching, the film is dried while being passed through the transport roller 137 until it reaches a predetermined residual solvent amount by the second drying device 136, and is wound into a roll by the winding device 138.

Hereinafter, each process will be described in detail.

(Dope preparation process)
In the method for producing the transparent polyimide resin film of the present invention, it is preferable that a dope is prepared by dissolving a transparent polyimide resin in a solvent, and the dope is used to form a film by a solution casting film forming method.

As the solvent, it is preferable to use a low-boiling solvent having a boiling point of 80 ° C. or lower as the main solvent because the film production process temperature (particularly the drying temperature) can be reduced and the thermal shrinkage can be reduced. Here, “used as a main solvent” means that if it is a mixed solvent, 55% by mass or more is used with respect to the total amount of the solvent, preferably 70% by mass or more, more preferably 80% by mass or more, and particularly preferably. Is 90% by mass or more. Of course, if it is used alone, it becomes 100% by mass.

The low boiling point solvent only needs to dissolve polyimide and other additives at the same time. For example, as the chlorinated solvent, dichloromethane, as the non-chlorinated solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, Methyl ethyl ketone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3- Difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2, 2,3,3,3-pentafluoro-1-propanol, nitroethane, methanol, ethanol, n-propanol, so- propanol, n- butanol, sec- butanol, tert- butanol and the like.

Among them, as the low boiling point solvent having a boiling point of 80 ° C. or less, among the above solvents, dichloromethane (40 ° C.), ethyl acetate (77 ° C.), methyl ethyl ketone (79 ° C.), tetrahydrofuran (66 ° C.), acetone (56.5 ° C.) And at least one selected from 1,3-dioxolane (75 ° C.) as a main solvent (the parentheses each represent a boiling point).

Moreover, as a solvent contained in the case of a mixed solvent, as long as it can dissolve the transparent polyimide resin of the present invention, it can be used as long as the effect of the present invention is not hindered. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylcaprolactam, hexamethylphosphoramide, tetra Methylene sulfone, dimethyl sulfoxide, m-cresol, phenol, p-chlorophenol, 2-chloro-4-hydroxytoluene, diglyme, triglyme, tetraglyme, dioxane, γ-butyrolactone, dioxolane, cyclopentanone, epsilon caprolactam, chloroform, etc. But Is capable of use, it may be used in combination of two or more thereof. In addition to these solvents, a poor solvent such as hexane, heptane, benzene, toluene, xylene, chlorobenzene, or o-dichlorobenzene is used to such an extent that the polyimide and the organic compound having a carbonyl group according to the present invention do not precipitate. May be.

Alcohol solvents can also be used. The alcohol solvent is preferably selected from methanol, ethanol, and butanol from the viewpoint of improving peelability and enabling high-speed casting. Of these, methanol or ethanol is preferably used. When the ratio of the alcohol in the dope increases, the web gels and peeling from the metal support becomes easy.

For dissolving polyimide and other additives, a method carried out at normal pressure, a method carried out below the boiling point of the main solvent, a method carried out under pressure above the boiling point of the main solvent, JP-A-9-95544, JP-A-9- Various dissolution methods can be used, such as a method using the cooling dissolution method described in JP-A-95557 or JP-A-9-95538, and a method using high pressure described in JP-A-11-21379.

The prepared dope is guided to a filter by a liquid feed pump or the like and filtered. For example, when the main solvent of the dope is dichloromethane, the gel-like foreign matter in the dope can be removed by filtering the dope at a temperature of boiling point at 1 atm of the dichloromethane + 5 ° C. or more. A preferred temperature range is 45 to 120 ° C, more preferably 45 to 70 ° C, and even more preferably within a range of 45 to 55 ° C.

Further, as a raw material for the resin used for preparing the dope, a material obtained by pelletizing polyimide and other compounds in advance can be preferably used.

(Casting film forming process)
The prepared dope is fed to a die through a feed pump (for example, a pressurized metering gear pump), and cast on an endless support that moves indefinitely, such as a stainless steel belt or a metal support such as a rotating metal drum. Cast the dope from the die into position.

The metal support in casting (cast) is preferably a mirror-finished surface, and the support is a stainless steel belt or a drum whose surface is plated with a casting, or a metal support such as a stainless steel belt or a stainless steel belt. Is preferably used. The cast width can be in the range of 1 to 4 m, preferably in the range of 1.5 to 3 m, more preferably in the range of 2 to 2.8 m. The support may not be made of metal, for example, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, polybutylene terephthalate (PBT) film, nylon 6 film, nylon 6,6 film, polypropylene film. A belt made of polytetrafluoroethylene or the like can be used. When using a polyimide as a flexible substrate, you may wind up a transparent polyimide resin film with the metal support body which cast the polyimide.

The traveling speed of the metal support is not particularly limited, but is usually 5 m / min or more, preferably 10 to 180 m / min, particularly preferably 80 to 150 m / min. As the traveling speed of the metal support increases, entrained gas is more likely to be generated, and the occurrence of film thickness unevenness due to disturbance is more pronounced.

The traveling speed of the metal support is the moving speed of the outer surface of the metal support.

The die has a shape that becomes gradually narrower toward the discharge port in the vertical cross section with respect to the width direction. In general, the die usually has tapered surfaces on the downstream side and the upstream side in the lower traveling direction, and a discharge port is formed in a slit shape between the tapered surfaces. A die made of metal is preferably used, and specific examples include stainless steel, titanium, and the like. In the present invention, when manufacturing films having different thicknesses, it is not necessary to change to dies having different slit gaps.

¡It is preferable to use a pressure die that can adjust the slit shape of the die base and easily make the film thickness uniform. Examples of the pressure die include a coat hanger die and a T die, and any of them is preferably used. Even when films with different thicknesses are continuously manufactured, the discharge rate of the dies is maintained at a substantially constant value. Therefore, when a pressure die is used, conditions such as extrusion pressure and shear rate are also substantially reduced. Maintained at a constant value. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and laminated.

(Solvent evaporation process)
The solvent evaporation step is a pre-drying step which is performed on a metal support and the cast film is heated on the metal support to evaporate the solvent.

To evaporate the solvent, for example, a method of blowing heated air from the casting membrane side and the back side of the metal support by a dryer, a method of transferring heat from the back side of the metal support by a heating liquid, a method of transferring heat from the front and back by radiant heat Etc. A method of appropriately selecting and combining them is also preferable. The surface temperature of the metal support may be the same as a whole or may vary depending on the position. The temperature of the heating air is preferably in the range of 10 to 220 ° C.

The temperature of the heating air (drying temperature) is preferably 200 ° C. or lower, more preferably 140 ° C. or lower, and further preferably 120 ° C. or lower.

In the solvent evaporation step, it is preferable to dry the cast film until the residual solvent amount is in the range of 10 to 150% by mass from the viewpoint of the peelability of the cast film and the transportability after peeling.

In the present invention, the amount of residual solvent can be expressed by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Here, M is the mass at a predetermined point of the casting membrane (film), and N is the mass when M is dried at 200 ° C. for 3 hours. In particular, M when calculating the amount of residual solvent achieved in the solvent evaporation step is the mass of the cast film immediately before the peeling step.

(Peeling process)
The cast film from which the solvent has evaporated on the metal support is peeled off at the peeling position.

The peeling tension when peeling the metal support from the casting film is usually in the range of 60 to 400 N / m. However, if wrinkles are likely to occur during peeling, peeling is performed with a tension of 190 N / m or less. It is preferable.

In the present invention, the temperature at the peeling position on the metal support is preferably in the range of −50 to 60 ° C., more preferably in the range of 10 to 40 ° C., and in the range of 15 to 40 ° C. Is most preferred.

The peeled film may be sent directly to the stretching process, or may be sent to the stretching process after being sent to the first drying process so as to achieve a desired residual solvent amount. In the present invention, from the viewpoint of stable conveyance in the stretching step, it is preferable that the film is sequentially sent to the first drying step and the stretching step after the peeling step.

(First drying step)
The first drying step is a drying step in which the film is heated and the solvent is further evaporated. The drying means is not particularly limited, and for example, hot air, infrared rays, a heating roller, microwaves and the like can be used. From the viewpoint of simplicity, it is preferable to dry with hot air or the like while transporting the film with rollers arranged in a staggered manner. The drying temperature is preferably in the range of 30 to 200 ° C., taking into account the amount of residual solvent and the stretching ratio during conveyance.

The drying temperature is preferably 200 ° C. or lower, more preferably 140 ° C. or lower, and further preferably 120 ° C. or lower.

¡By reducing the drying temperature, the heat shrinkage rate of the film can be increased.

(Stretching process)
By stretching the film peeled from the metal support, the film thickness, flatness, orientation and the like of the film can be controlled.

In the film production method of the present invention, it is preferable to stretch in the longitudinal direction or the width direction.

The stretching operation may be performed in multiple stages. Moreover, when performing biaxial stretching, simultaneous biaxial stretching may be performed and you may implement in steps. In this case, stepwise means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any one of the stages. Is also possible.

Thus, for example, the following stretching steps are possible:
-Stretch in the longitudinal direction-> Stretch in the width direction-> Stretch in the longitudinal direction-> Stretch in the longitudinal direction-Stretch in the width direction-> Stretch in the width direction-> Stretch in the longitudinal direction-> Stretch in the longitudinal direction Includes stretching in one direction and contracting the other while relaxing the tension. The preferred draw ratio for simultaneous biaxial stretching can be in the range of x1.01 to x1.5 in both the width direction and the longitudinal direction.

The amount of residual solvent at the start of stretching is preferably in the range of 0.1 to 200% by mass.

If the amount of the residual solvent is 0.1% by mass or more, the effect of improving the flatness by stretching is obtained, and if it is 200% or less, stretching is easy.

In the method for producing a transparent polyimide resin film of the present invention, the film may be stretched in the longitudinal direction or the width direction, preferably in the width direction, so that the film thickness after stretching is in a desired range. The transparent polyimide resin film is preferably stretched in a temperature range of (Tg−200) to (Tg + 100) ° C. with respect to the glass transition temperature (Tg). If it extends in the said temperature range, since a extending | stretching stress can be reduced, a haze will become low. Moreover, generation | occurrence | production of a fracture | rupture is suppressed and the transparent polyimide resin film excellent in planarity and the coloring property of transparent polyimide resin film itself is obtained. The stretching temperature is more preferably in the range of (TgL−150) to (TgH + 50) ° C.

In the method for producing a transparent polyimide resin film according to the present invention, the self-supporting film peeled from the support can be stretched in the longitudinal direction by regulating the running speed with a stretching roller.

In order to stretch the film in the width direction, for example, the entire width of the film is held with clips or pins in the width direction in the entire drying process or a part of the process as disclosed in JP-A-62-46625. A method of drying while drying (referred to as a tenter method), among which a tenter method using a clip is preferably used.

The film stretched in the longitudinal direction or the unstretched film is preferably introduced into the tenter in a state where both ends in the width direction are held by the clip, and stretched in the width direction while running with the tenter clip.

When stretching in the width direction, stretching in the width direction of the film at a stretching speed in the range of 50 to 1000% / min is preferable from the viewpoint of improving the flatness of the film.

If the stretching speed is 50% / min or more, the planarity is improved and the film can be processed at high speed, which is preferable from the viewpoint of production aptitude, and if it is within 1000% / min, the film is broken. Can be processed without any problem.

More preferable stretching speed is in the range of 100 to 500% / min. The stretching speed is defined by the following formula.

Stretching speed (% / min) = [(d ₁ / d ₂ ) −1] × 100 (%) / t
(In the above formula, d ₁ is the width dimension in the stretching direction of the resin film after stretching, d ₂ is the width dimension in the stretching direction of the resin film before stretching, and t is the time (min) required for stretching. .)
In the stretching step, usually, after stretching, holding and relaxation are performed. That is, in this step, it is preferable to perform a stretching step for stretching the film, a holding step for holding the film in a stretched state, and a relaxation step for relaxing the film in the stretched direction in this order. In the holding step, the drawing at the draw ratio achieved in the drawing step is held at the drawing temperature in the drawing step. In the relaxation stage, the stretching in the stretching stage is held in the holding stage, and then the stretching is relaxed by releasing the tension for stretching. The relaxation step may be performed at a temperature lower than the stretching temperature in the stretching step.

(Second drying step)
Next, the stretched film is heated and dried. In the case of heating the film with hot air or the like, a means for preventing the mixing of used hot air by installing a nozzle capable of exhausting used hot air (air containing solvent or wet air) is also preferably used. The hot air temperature is more preferably in the range of 40 to 350 ° C. The drying time is preferably about 5 seconds to 30 minutes, more preferably 10 seconds to 15 minutes.

Further, the heating and drying means is not limited to hot air, and for example, infrared rays, heating rollers, microwaves, etc. can be used. From the viewpoint of simplicity, it is preferable to dry with hot air or the like while transporting the film with rollers arranged in a staggered manner. The drying temperature is preferably in the range of 40 to 150 ° C. from the viewpoint of easy heating shrinkage. More preferably, it is 40 to 120 ° C.

In the second drying step, it is preferable to dry the film until the residual solvent amount is 0.5% by mass or less.

(Winding process)
A winding process is a process of winding up the obtained transparent polyimide resin film, and cooling to room temperature. The winding machine may be a commonly used one, and can be wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, a program tension control method with a constant internal stress, or the like.

The thickness of the transparent polyimide resin film is not particularly limited, and is preferably in the range of 1 to 200 μm, particularly 1 to 100 μm, for example.

In the winding process, both ends of the transparent polyimide resin film sandwiched between tenter clips when stretched and conveyed may be slit. The slit end portion of the transparent polyimide resin film is preferably cut into a width of 1 to 30 mm, then dissolved in a solvent and reused as a recycled material.

Each process from the solvent evaporation process to the winding process described above may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas. Moreover, each process, especially a drying process and a extending process, are performed in consideration of the explosion limit concentration of the solvent in the atmosphere.

(Heating process)
After the winding step, a heating step of further heat-treating the transparent polyimide resin film dried in the second drying step in order to improve imidization in the polymer chain molecules and between the polymer chain molecules to improve mechanical properties. You can go.

In addition, the said 2nd drying process may serve as a heating process.

The heating means is performed using a known means such as hot air, an electric heater, or a microwave. As the electric heater, the above-described infrared heater can be used.

In the heating step, if the transparent polyimide resin film is heated rapidly, problems such as an increase in surface defects occur, and therefore it is preferable to select a heating method as appropriate. The heating step is preferably performed in a low oxygen atmosphere.

When the heating temperature in the second drying step and the heating step exceeds 450 ° C., the energy required for heating becomes very large, resulting in an increase in manufacturing cost and an increase in environmental load. The following is preferable.

In addition, after the winding process, before or after the heating process, the process of slitting the width direction end of the transparent polyimide resin film, the process of neutralizing this when the transparent polyimide resin film is charged, etc. May be further performed.

<Shape of transparent polyimide resin film>
The transparent polyimide resin film of the present invention is preferably long, specifically, preferably has a length in the range of about 100 to 10,000 m, and is wound into a roll. Further, the width of the transparent polyimide resin film of the present invention is preferably 1 m or more, more preferably 1.4 m or more, and particularly preferably 1.4 to 4 m.

The transparent polyimide resin film of the present invention can be used as a coating film in addition to the single film as described above. For example, a transparent polyimide resin composition (infrared absorbing composition) of the present invention containing an infrared absorbing compound is applied as an infrared absorbing layer on a silicon wafer or a color filter for an image sensor and dried to form a film. The film can be used as it is without being peeled off, or can be used without being peeled off by applying a transparent polyimide resin composition as an infrared absorbing layer to an elemental glass or phosphoric acid glass and drying it.

The infrared absorbing layer is preferably a near infrared absorbing layer.
In the case of a resin film, the film thickness of the infrared absorbing layer is usually 20 to 200 μm, preferably 50 to 100 μm. In the case of coating by spin coating or die coating, it is usually 0.1 to 100 μm, preferably 0.5 to 10 μm.
When the film thickness is in the above range, an infrared absorption layer having excellent infrared absorption ability and transmittance and strength in the range of 430 to 580 nm can be obtained.

<Board>
The transparent polyimide resin film of the present invention may be formed on a substrate, and there is no particular limitation on the type of glass, plastic and the like, and it may be transparent or opaque.
When extracting light from the support substrate side, the support substrate is preferably transparent.
Examples of the transparent support substrate preferably used include glass, quartz, transparent electrodes such as ITO, and transparent resin films. Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloolefin resins such as polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.
The glass substrate is not particularly limited as long as it is a glass substrate containing silicate as a main component, and examples thereof include a quartz glass substrate having a crystal structure. In addition, an absorption glass substrate in which CuO or the like is added to fluorophosphate glass or phosphate glass, a borosilicate glass substrate, a soda glass substrate, a colored glass substrate, an alkali-free glass substrate, a quartz glass substrate, or the like is used. In particular, glass substrates such as alkali-free glass substrates and low α-ray glass substrates are preferred.

<Other constituent layers>
As one of the embodiments, the other constituent layers constituting the image sensor are not particularly limited. For example, the imaging element support substrate, the light receiving unit, the mixed polarization filter, the mixed color filter, and the microlens. A dielectric multilayer film, an antireflection layer, a hard coat layer, and the like.

The dielectric multilayer film is configured by alternately laminating a low refractive index dielectric film and a high refractive index dielectric film. Here, the low refractive index and the high refractive index mean having a low refractive index and a high refractive index with respect to the refractive index of the adjacent layer.
The high refractive index dielectric film preferably has a refractive index (nd) of 1.6 or more, more preferably in the range of 2.2 to 2.5.
Examples of the high refractive index dielectric film material include Ta ₂ O ₅ , TiO ₂ , and Nb ₂ O ₅ . Of these, TiO ₂ is preferable from the viewpoints of film formability, reproducibility in refractive index, and stability.
On the other hand, the low refractive index dielectric film preferably has a refractive index (nd) of less than 1.6, more preferably 1.45 or more and less than 1.55, and even more preferably 1.45 to 1. Within the range of .47. Examples of the low refractive index dielectric material include SiO _x N _y . SiO ₂ is desirable from the viewpoints of film reproducibility, stability, economy, and the like.
For the dielectric multilayer film, for example, a vacuum film formation process such as a CVD method, a sputtering method, or a vacuum deposition method, or a wet film formation process such as a spray method or a dip method can be used.
In the dielectric multilayer film used in the present invention, the average transmittance of light having a wavelength of 430 to 620 nm is preferably 90% or more, more preferably 92% or more, and further preferably 95% or more in the spectral transmittance curve at an incident angle of 0 °. . In the spectral transmittance curve at an incident angle of 0 °, the average transmittance of light having a wavelength of 710 to 1100 nm is preferably 10% or less, more preferably 8% or less, and further preferably 5% or less. Further, in the spectral transmittance curve at an incident angle of 0 °, it is preferable to have a wavelength at which the transmittance is 50% at a wavelength of 350 to 430 nm and a wavelength at which the transmittance is 50% at a wavelength of 650 to 750 nm.
For this purpose, the dielectric multilayer film is preferably 15 or more, more preferably 25 or more, more preferably 30 or more as the total number of laminated layers of the low refractive index dielectric layer and the high refractive index dielectric layer. Is more preferable. However, when the total number of laminated layers increases, the warp of the dielectric multilayer film increases, and the total film thickness increases. Therefore, 100 layers or less is preferable, 75 layers or less are more preferable, and 60 layers or less are more preferable. The film thickness is preferably thin from the viewpoint of reducing the thickness of the optical filter after satisfying the preferred number of seat layers.
The film thickness of such a dielectric multilayer film is preferably in the range of 2 to 10 μm.

<Use of transparent polyimide resin film>
The transparent polyimide resin film of the present invention can be preferably used as a transparent FPC, an in-vehicle film, a film member of an image display device, and a sensor film. The device to be applied is not particularly limited. For example, an organic electroluminescence (EL) image display device, a liquid crystal image display device (LCD), an organic photoelectric conversion device, a touch panel, a polarizing plate, a retardation film, a transparent FPC film, an image Examples include an infrared cut film for sensors, an infrared cut film for iris authentication, and the like.

(Touch panel)
The polyimide resin film of the present invention can be used as a transparent conductive film for a touch panel by providing the film with a transparent conductive layer. The shape of the pattern of the transparent conductive layer is not particularly limited as long as it is a pattern that works well as a touch panel (for example, a capacitive touch panel). For example, JP 2011-511357 A, JP 2010-164938 A JP-A-2008-310550, JP-T-2003-511799, JP-T-2010-541109, and the like.

A touch panel can be produced by laminating a transparent conductive film patterned on the x-axis and a transparent conductive film patterned on the y-axis using an adhesive film and providing a cover glass on the outermost surface. A touch panel display device can be manufactured by combining with a display device.

(LED lighting device)
The transparent polyimide resin film of the present invention can be used as an LED substrate to provide an LED certification device. For example, a composite substrate with a double-sided substrate or an aluminum plate can be used. In the case where heat dissipation is required as the brightness of the LED increases, it is possible to improve the heat dissipation by combining with an aluminum plate. The present invention can also be applied to an organic electroluminescence lighting device using an organic material.

(Front member for flexible display)
The transparent polyimide resin film of the present invention can also be used as a front member for a flexible display.

As a flexible display on which a front member for flexible display is mounted, for example, an organic EL device in which an organic functional layer such as a light emitting layer is laminated on a substrate, a gas barrier film, a film color filter, polarizing plate protection on one side or both sides A polarizing plate including a film, a film-type touch sensor, and the like are laminated in this order. The front member for flexible display is laminated | stacked on the film type touch sensor of the flexible display comprised as mentioned above, for example.

In addition, the transparent polyimide resin film of this invention may be used for the board | substrate of the organic EL device which comprises the said flexible display, and may be used for the polarizing plate protective film of the polarizing plate which comprises the said flexible display.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

Dicarboxylic acid anhydrides and diamines used for the synthesis of polyimide were samples purified by recrystallization or column chromatography.

[Example 1]
<Preparation of polyimide resin film 1>
To a 4-neck flask equipped with a dry nitrogen gas inlet tube, a condenser, a Dean-Stark agglomerator filled with toluene, and a stirrer, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1, 4,4.4 g (0.10 mol) of 3,3,3-hexafluoropropane dianhydride (manufactured by Daikin Industries, Ltd.) was added to N, N-dimethylacetamide (400 g), and the mixture was stirred at room temperature under a nitrogen stream.

Then, 18.8 g (0.11 mol) of 2,4-diethyl-6-methyl-1,3-phenylenediamine was added, and the mixture was heated and stirred at 40 ° C. for 10 hours. 0.2g of benzoic anhydride was added to this reaction liquid, and it heated and stirred for 3 hours. The reaction solution was uniformly cast on a stainless steel belt support at a temperature of 40 ° C. and a width of 150 mm. The temperature of the stainless steel belt was controlled at 40 ° C. Next, the stainless steel belt was put into a reduced pressure oven at 50 ° C., the pressure was reduced to 0.1 kPa, and heating was performed at a reduced pressure for 30 minutes. Thereafter, the temperature was raised to 220 ° C. by 1 ° C. in 1 minute while maintaining the reduced pressure, and then heated under reduced pressure for 6 hours. The oven was cooled and the film was peeled from the stainless steel belt to obtain a polyimide resin film 1 having a thickness of 40 μm.

Infrared absorption analysis (IR) measurement was performed using FT / IR-670Plus manufactured by JASCO Corporation. Absorbance of IR imide group (near 1375CM ^-1 ) / (absorbance of IR benzene ring (near 1500 cm ^-1 )) )), It was confirmed that the imidation ratio was 95% or more.

<Preparation of polyimide resin films 2 to 60>
Polyimide resin films 2 to 60 were obtained by the same molar ratio and synthesis method as those of polyimide resin film 1 except that the monomers used and the end-capping compounds were changed to compounds capable of obtaining the partial structure shown in Table 2. When synthesizing each polyimide, when a plurality of dicarboxylic acid anhydrides are used, a plurality of types of dicarboxylic acid anhydrides are dissolved simultaneously, and when a plurality of diamine compounds are used, they are simultaneously dissolved in N, N-dimethylacetamide. It was added dropwise to the reaction solution later. The total amount of the dicarboxylic acid to be used, the total amount of the diamine compound, and the total amount of the end-capping agent were added so as to have the same molar amount as the material constituting the polyimide resin film 1. Moreover, when using together 2 types of dicarboxylic acid or a diamine compound, the mixing ratio of 2 types of compounds was added by equimolar amount of 1: 1.

For the obtained polyimide resin films 2 to 60, the imidization rate was measured by the same method as for the polyimide resin film 1, and it was confirmed that the imidization rate was 95% or more.

(Preparation of polyimide resin film 61)
To a four-necked flask equipped with a dry nitrogen gas inlet tube, a cooler, and a stirrer, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane 48.1 g (0.11 mol) of anhydride (manufactured by Daikin Industries) was added to N, N-dimethylacetamide (400 g), and the mixture was stirred at room temperature under a nitrogen stream.

2,2′-bis (trifluoromethyl) benzidine (32.0 g, 0.10 mol) was added thereto, and the mixture was heated and stirred at 40 ° C. for 10 hours. The reaction solution was uniformly cast on a stainless steel belt support at a temperature of 40 ° C. and a width of 150 mm. The temperature of the stainless steel belt was controlled at 40 ° C.

Next, the stainless steel belt was put into a 50 ° C. vacuum oven and the pressure was reduced to 0.1 kPa, followed by heat drying for 1 hour. Thereafter, the temperature was set to 220 ° C., and heat drying was performed for 6 hours. The oven was cooled and the film was peeled from the stainless steel belt to obtain a polyimide resin film 61 having a thickness of 40 μm.
It was confirmed that the imidation ratio was 95% or more by the same method as for the polyimide resin film 1.

(Preparation of polyimide resin films 62 to 64)
Polyimide resin films 62 to 64 were obtained by the same molar ratio and synthesis method as those of the polyimide resin film 61 except that the monomers used and the end-capping compounds were changed to compounds that give the partial structures shown in Table 2. The imidization rate was measured by the same method as that for the polyimide resin film 1, and it was confirmed that the imidization rate was 95% or more.

(Preparation of polyimide resin films 65-73)
Polyimide resin films 65 to 73 were obtained by the same molar ratio and synthesis method as those of the polyimide resin film 1 except that the monomers used and the end-capping compounds were changed to compounds capable of obtaining the partial structures shown in Table 2. It was confirmed that the imidation ratio was 95% or more by the same method as for the polyimide resin film 1.

(Preparation of polyimide resin film 74 (comparative example))
A polyimide resin having a terminal sealed with phthalic anhydride was prepared in the same manner as described in paragraphs [0094] to [0096] of JP2012-251080A. The obtained resin was uniformly cast on a stainless steel belt support at a temperature of 40 ° C. and a width of 150 mm so that the thickness after drying was 40 μm. The temperature of the stainless steel belt was controlled at 40 ° C. Next, the stainless steel belt was put into a reduced pressure oven at 50 ° C., the pressure was reduced to 0.1 kPa, and heating was performed at a reduced pressure for 30 minutes. Thereafter, the temperature was raised to 200 ° C. by 1 ° C. in 1 minute while maintaining the reduced pressure, and then heated under reduced pressure for 4 hours. The oven was cooled and the film was peeled from the stainless steel belt to obtain a polyimide resin film 74 having a thickness of 40 μm.

It was confirmed that the imidation ratio was 95% or more by the same method as for the polyimide resin film 1.

The terminal group of the synthesized comparative compound was made to have the following partial structure.

The elastic modulus, bending resistance, and YI value of the polyimide resin films 1 to 74 produced as described above were evaluated as follows. The weight average molecular weights of the polyimide resin films 1 to 74 were all in the range of 100,000 to 250,000.

(Elastic modulus)
The prepared polyimide resin film was stored for 24 hours in an environment of 23 ° C. and 55% RH. Thereafter, the elastic modulus was measured according to the method described in JIS K7127 under the environment of 23 ° C. and 55% RH. Tensilon RTA-100 manufactured by Orientec Co., Ltd. was used as the tensile tester. The shape of the test piece was No. 1 type test piece, and the test speed was 10 mm / min. Based on the numerical value of the obtained elastic modulus, it was evaluated according to the following criteria.
A 5.0 GPa or more B 4.0 GPa or more and less than 5.0 GPa C less than 4.0 GPa (bending resistance)
The prepared polyimide resin film was subjected to a bending resistance test (sliding bending test) using a bending fatigue tester. Evaluation was continued under the conditions of a load of 500 G, a refraction angle of 135 °, a refraction cycle of 175 cpm, and a refractive portion locality radius of 0.38 mm until the bent portion became cloudy by visual observation. The polyimide resin film of the present invention was an excellent polyimide resin film with no white turbidity at the bent portion even when the number of folding times was 5000 times or more, and little curling after the bending test.
A: 10,000 times or more B: 6,000 times or more and less than 10,000 times C: Less than 6,000 times (YI value)
The yellow index value is measured according to JIS Z8701 using the spectrophotometer U-3300 manufactured by Hitachi High-Technologies Corporation and the attached saturation calculation program. The tristimulus values X, Y, and Z of the light source color being obtained were obtained, and the yellow index value was obtained according to the following formula.

The YI value was evaluated as a measure of the transparency of the polyimide resin film.

Yellow index (YI) = 100 (1.28X-1.06Z) / Y
A: Less than 2.0 B: 2.0 or more and less than 4.0 C: 4.0 or more and less than 5.0 D: 5.0 or more and less than 6.0 The above evaluation results and the composition of the polyimide resin are summarized. The results are shown in Table 2 and Table 3.

The NICS values in the table were calculated using Gaussian 03 (Revision B.03, US Gaussian software). Specifically, from the structure optimized using B3LYP (density functional method) as the calculation method and 6-31 + G (function in which the diffusion gauss function is added to the split valence basis set) as the basis function, the NMR shielding constant It is calculated by a calculation method (GIAO).

At that time, the NICS value was calculated by substituting the * part of the partial structure of the exemplified compound and the comparative compound with a saturated hydrocarbon.

In the table, evaluation 1 is the value of the ring with the largest NICS value among the aromatic rings, and was classified according to the following criteria.
A: The value of the ring with the largest NICS value among aromatic rings is -15.0 or more and -10.0 or less B: The value of the ring with the largest NICS value among aromatic rings is -10.0 Greater than -9.0 C: The value of the ring with the largest NICS value among the aromatic rings is greater than -9.0 and less than -8.0 D: The ring with the largest NICS value among the aromatic rings The value of is greater than −8.0 E: No aromatic ring In the table, the evaluation 2 is the case where there are two or more aromatic rings, and was classified according to the following criteria.
A: having two or more aromatic rings having a NICS value of −15.0 or more and −8.0 or less B: one or more aromatic rings having a NICS value of greater than −8.0 and −7.0 or less, C having one aromatic ring having a NICS value of -15.0 or more and -8.0 or less C: having two or more aromatic rings having a NICS value of greater than −8.0 and −7.0 or less D: A˜ As is clear from Tables 2 and 3 that do not fall under C, the transparent polyimide resin film of the present invention had good elastic modulus, bending resistance, and YI value.

[Example 2]
Of the polyimide resin films prepared in Example 1, polyimide resin film numbers 1, 6, 30, 43 to 57, 66, 69, 70, 72 were redissolved in a mixed solvent of dichloromethane and ethanol, and film number 24 , 33 were redissolved in cyclohexanone, and each polyimide resin film was prepared by the following method.

<Preparation of polyimide resin film C1>
The polyimide resin film 1 produced in Example 1 was dissolved in 30 g, 200 g of dichloromethane, and 5 g of ethanol, formed on a glass substrate at 25 ° C., and then peeled and dried by heating in an oven at 120 ° C. for 20 minutes for 40 μm polyimide. Resin film C1 was obtained.

<Preparation of polyimide resin film C2>
A polyimide resin film C2 was produced in the same manner as the production of the polyimide resin film C1, except that the polyimide resin film to be re-dissolved was changed to the polyimide resin film 6 of Example 1.

<Preparation of polyimide resin films C3 and C4>
Polyimide resin films C3 and C4 were produced in the same manner as the production of the polyimide resin film C1, except that the polyimide resin film 24 and the polyimide resin film 33 were changed and the solvent was changed to 200 g of cyclohexanone.

<Preparation of polyimide resin films C5 to C24>
Polyimide resin films C5 to C24 were produced in the same manner as the production of the polyimide resin film C1, except that the polyimide resin film 1 was changed to a film having the resin composition shown in the table.

For the obtained polyimide resin films C1 to C25, the elastic modulus, bending resistance, and YI value were evaluated in the same manner as in Example 1.

The above evaluation results and the composition of the polyimide resin are summarized in Table 4.

As can be seen from Table 4, the transparent polyimide resin film of the present invention had good elastic modulus, bending resistance, and YI value.

[Example 3]
The following additives were added to the polyimide resin films C1 to C24 obtained in Example 2 at a ratio of 5% by mass with respect to the polyimide resin to prepare polyimide resin films D1 to D24 in the same manner as in Example 2. Evaluation similar to Example 2 was performed with respect to each obtained polyimide resin film.

The above evaluation results and the composition of the polyimide resin are summarized in Table 5.

As additive 4, a compound synthesized by the same method as that for ester compound 1 described in paragraph [0243] of JP2013-232005A was used.

As additive 5, a compound synthesized by the same method as that for ester compound 4 described in paragraph [0245] of JP2013-232005A was used.

For the obtained polyimide resin films D1 to D24, the elastic modulus, bending resistance, and YI value were evaluated in the same manner as in Example 2.

As can be seen from Table 5, the transparent polyimide resin film of the present invention had good elastic modulus, bending resistance, and YI value. In addition, it has been clarified that the dimensional stability due to wet heat is improved when stored in an environment of 60 ° C. and 90% RH for 500 hours.

[Example 4]
<Preparation of polyimide resin film E1>
30 g of the polyimide resin film 11 prepared in Example 1, 200 g of dichloromethane, 5 g of ethanol, and 30 mg of the following infrared-absorbing organic dye 1 were added and dissolved, formed on a glass substrate at 25 ° C., and 120 ° C. after peeling. Was dried in an oven for 20 minutes to obtain a 40 μm polyimide resin film E1.

<Preparation of polyimide resin film E2>
30 g of the polyimide resin film 44 prepared in Example 1, 200 g of dichloromethane, 5 g of ethanol, and 30 mg of the following organic dye 1 were added and dissolved, and the film was formed on a glass substrate at 25 ° C. A 40 μm polyimide resin film E <b> 2 was obtained by heat drying for a few minutes.

<Preparation of polyimide resin film E3>
30 g of the polyimide resin film 59 produced in Example 1, 200 g of dichloromethane, 5 g of ethanol, and 30 mg of the following organic dye 1 were added and dissolved, formed on a glass substrate at 25 ° C., and peeled off in a 120 ° C. oven. A 40 μm polyimide resin film E3 was obtained by heat drying for a few minutes.

<Preparation of polyimide resin film E4>
30 g of the polyimide resin film 61 prepared in Example 1, 200 g of dichloromethane, 5 g of ethanol, and 30 mg of the following organic dye 1 were added and dissolved, and the film was formed on a glass substrate at 25 ° C. A 40 μm polyimide resin film E4 was obtained by heat drying for minutes.

<Preparation of polyimide resin film E5>
30 g of the polyimide resin film 62 produced in Example 1, 200 g of dichloromethane, 5 g of ethanol, and 30 mg of the following organic dye 1 were added and dissolved, formed on a glass substrate at 25 ° C., and after peeling, 20 in a 120 ° C. oven. A 40 μm polyimide resin film E5 was obtained by heat drying for a few minutes.

<Preparation of polyimide resin films E6 to E10>
Polyimide resin films E6 to E10 were produced in the same manner except that the organic dye of the polyimide resin films E1 to E5 was changed to the organic dye 2.

<Preparation of polyimide resin films E11 to E15>
Polyimide resin films E11 to E15 were produced in the same manner except that the organic dye of the polyimide resin films E1 to E5 was changed to the organic dye 3.

<Heat resistance evaluation>
The absorbance after heating the polyimide resin films E1 to E5 on a hot plate at 250 ° C. for 10 minutes was measured.
The absorbances at the maximum absorption wavelengths of the polyimide resin films E1 to E3 and E6 to E8 varied within 1 to 5%, while E11 to E13 varied within 6 to 10%, but the polyimide resin films E4 to E5, E9 ~ E10 and E14 ~ E15 fluctuated 20% or more.
From this, it became clear that the heat resistance of the dye in the film obtained by adding an organic dye to the polyimide resin of the present invention has been improved. Although it is presumed, it is thought that decomposition | disassembly of a pigment | dye is suppressed by suppressing a vibration because the terminal of the polyimide resin of this invention interacts.

<Production of dielectric multilayer film>
An IR cut filter was produced by forming a dielectric multilayer film on the polyimide resin films E1 to E15 by the following method.

(Deposition of near-infrared reflective dielectric multilayer film as the first dielectric multilayer film)
On one main surface of the polyimide resin film, using an IAD vacuum vapor deposition apparatus, starting with a high refractive index film, a high refractive index film and a low refractive index film are alternately formed for a total of 40 layers (total layer thickness) And 5920 nm) as a first dielectric multilayer film and a gold infrared reflective dielectric multilayer film (hereinafter referred to as dielectric multilayer film R). ) Was formed. Note that TiO ₂ was used as the high refractive index material, and SiO ₂ was used as the low refractive index material.
(Deposition of dielectric layer)
On the surface opposite to the side having the dielectric multilayer film R obtained above, using a vacuum deposition apparatus, a dielectric composed of two layers of a 30 nm layer made of Al ₂ O ₃ and a 165 nm layer made of SiO ₂ is used. The body layer was formed in this order. The refractive index of the layer made of Al ₂ O _{3 formed} was 1.60, and the refractive index of the layer made of SiO _{2 formed} was 1.45.

An image sensor was prepared using the composition as a mixed color filter with reference to Japanese Patent Application Laid-Open No. 2016-72266. CMOS sensors and CCD sensors using polyimide resin films E1 to E3, E6 to E8, and E11 to E13 Showed good performance. On the other hand, polyimide resin films E4 to E5, E9 to E10, and E14 to E15 did not satisfy sufficient performance. Presumably, the polyimide resin films E4 to E5, E9 to E10, and E14 to E15 are considered to be due to the progress of decomposition of the organic dye due to the heat and stress applied during the dielectric multilayer film fabrication process and sensor fabrication.

[Example 5]
An IR cut filter was prepared by forming a polyimide thin film to which a dielectric multilayer film and a dye were added on a glass substrate by the following method.

(Deposition of near-infrared reflective dielectric multilayer film as the first dielectric multilayer film)
Asahi Glass fluorophosphate glass substrate NF-50TX (hereinafter referred to as “glass substrate A”) having a size of 76 mm × 76 mm × 0.214 mm is obtained by using Asahi Glass hydrofluoroether solvent Asahiklin (registered trademark) AE3000 (trade name). Washed for 10 minutes with a sonic cleaner.
A high refractive index film and a low refractive index film are alternately formed on one main surface of the cleaned glass substrate A obtained above using an IAD vacuum vapor deposition apparatus, and then totaled. It is referred to as a near-infrared reflective dielectric multilayer film (hereinafter, dielectric multilayer film R) as a first dielectric multilayer film having 40 layers (total layer thickness: 5950 nm). ) Was formed. Note that TiO ₂ was used as the high refractive index material, and SiO ₂ was used as the low refractive index material.

(Deposition of dielectric layer)
The glass substrate A having the dielectric multilayer film R obtained above was washed again with an ultrasonic cleaner for 20 minutes using the Asahi Glass hydrofluoroether solvent Asahiklin (registered trademark) AE3000. On the surface opposite to the side having the dielectric multilayer film R of the cleaned glass substrate A obtained above, a 30 nm layer made of Al ₂ O ₃ and a 170 nm layer made of SiO ₂ were formed using a vacuum deposition apparatus. These two dielectric layers were formed in this order. The refractive index of the layer made of Al ₂ O _{3 formed} was 1.60, and the refractive index of the layer made of SiO _{2 formed} was 1.45.

(Near infrared absorption layer deposition)
30 g of polyimide resin film 11 produced in Example 1, 400 g of dichloromethane, 10 g of ethanol, and 1.2 g of organic dye 1 used in Example 4 were added and stirred and dissolved at room temperature to obtain a coating solution.
The obtained coating solution is applied onto the dielectric layer of the glass substrate A having the dielectric multilayer film R and the dielectric layer on both main surfaces obtained above by a spin coater, and dried by heating at 100 ° C. for 5 minutes. Thus, a laminate 1 was obtained in which a near-infrared absorbing layer having a thickness of 1 μm was laminated in this order.
In the same manner, laminates 2 to 5 were obtained using polyimide films 44, 59, 61 and 62 of Example 1. Further, by changing the dye 1 to the dye 2, the laminates 6 to 10 were changed to the dye 3, and the laminates 11 to 15 were obtained.

An image pickup device was manufactured using the composition as a mixed color filter with reference to Japanese Patent Application Laid-Open No. 2016-72266. As a result, a CMOS sensor and a CCD sensor using the laminates 1 to 3, 6 to 8, and 11 to 13 were used. Showed good performance. On the other hand, the laminates 4, 5, 9, 10, 14, and 15 did not satisfy sufficient performance. Presumably, the laminates 4, 5, 9, 10, 14, and 15 are considered to have been caused by the decomposition of the organic dye due to heat and stress applied during the dielectric multilayer film production process and sensor production.

The present invention is used for a transparent polyimide resin film, a transparent polyimide resin composition, a transparent polyimide resin film, an infrared absorbing composition, an infrared cut filter, and a method for producing a transparent polyimide resin film, which have good film transparency and excellent mechanical strength. can do.

101

Melting pot

103, 106, 112, 115

Filter

104, 113

Stock pot

102, 105, 111, 114

Liquid feed pump

108, 116 Conduit 110 Additive charging pot 120 Merge pipe 121 Mixer 130 Pressure die 131 Metal belt 132 Web 133 Peeling position 134 First drying device 135 Stretching device 136 Second drying device 137 Conveying roller 138 Winding device 141 Loading kettle 142 Stock kettle 143 Pump 144 Filter

Claims

A transparent polyimide resin containing a polyimide having an aromatic moiety,
At least one end of the polyimide has an end group having an aromatic ring with a NICS value in the range of -15.0 to -8.0, and a NICS value in the range of -15.0 to -7.0. A transparent polyimide resin having any one of terminal groups having two or more aromatic rings.
2. The transparent polyimide resin according to claim 1, wherein the polyimide is a polymer of an aromatic dicarboxylic acid anhydride and an aromatic diamine having a sterically hindering group at the ortho position of the amino group.
The transparent polyimide resin according to claim 1 or 2, wherein the polyimide is a polymer of an alicyclic dicarboxylic acid anhydride and an aromatic diamine.
4. The terminal group according to claim 1, wherein the terminal group is a terminal group having one or more aromatic rings having a NICS value in the range of -15.0 to -10.0. The transparent polyimide resin as described in the item.
The said polyimide has the structure represented by following General formula (1) or General formula (2), The transparent polyimide resin as described in any one of Claim 1- Claim 4 characterized by the above-mentioned.

(Wherein A and R each independently represents an aromatic ring, an aromatic heterocyclic ring, an aliphatic hydrocarbon group having 2 to 39 carbon atoms, or an alicyclic hydrocarbon group having 2 to 39 carbon atoms, A and R may be —O—, —SO 2 —, —CO—, —CH 2 —, —C (CH 3 ) 2 —, —OSi (CH 3 ) 2 —, A plurality of aromatic hydrocarbon rings, aromatic heterocycles, aliphatic hydrocarbon groups having 2 to 39 carbon atoms via at least one linking group of -C 2 H 4 O-, -S-, and a simple bond; Alternatively, an alicyclic hydrocarbon group may be linked, provided that at least one aromatic moiety is present in the structure represented by A or R. R 1 to R 8 are each independently a polyimide. Represents a terminal group, provided that at least one of R 1 to R 4 and at least one of R 5 to R 8 are N Two end groups having one or more aromatic rings having an ICS value in the range of -15.0 to -8.0, or two aromatic rings having an NICS value in the range of -15.0 to -7.0. It is a terminal group having two or more.)
In the said General formula (1) or General formula (2), said A represents the following structure, The polyimide resin of Claim 5 characterized by the above-mentioned.

[The above structure is bonded to N in the general formula (1) and the general formula (2) in the * part. ]
In the said General formula (1) or General formula (2), said R represents the following structure, The polyimide resin of Claim 5 or Claim 6 characterized by the above-mentioned.

[The above structure is bonded to the carbonyl group in the imide group at the * moiety. ]
A transparent polyimide resin composition comprising the transparent polyimide resin according to any one of claims 1 to 7.
A transparent polyimide resin film comprising the transparent polyimide resin according to any one of claims 1 to 7.
An infrared-absorbing composition comprising the transparent polyimide resin according to any one of claims 1 to 7.
An infrared cut filter comprising the transparent polyimide resin according to any one of claims 1 to 7.
A step of preparing a dope obtained by dissolving the transparent polyimide resin according to any one of claims 1 to 7 in an organic solvent, and casting the dope on a support to form a film The manufacturing method of the transparent polyimide resin film characterized by including a process.