JP6772519B2 - Polyimide film, its manufacturing method, transparent conductive film and touch panel - Google Patents

Description

The present invention relates to a polyimide film, a method for producing the same, a transparent conductive film, and a touch panel. More specifically, the present invention has good film transparency and has good durability against keystrokes when used as a base material for the transparent conductive film of a touch panel. The present invention relates to a film and a method for producing the film.

In the field of image display devices, a technique for inputting information by touching with a finger or the like is known. Among them, as a technology that has attracted particular attention, there is a display device that enables information input similar to that when a normal button is pressed with a finger or the like by touching various buttons displayed on the display with a finger or the like. This technology makes it possible to share the display and buttons, which brings great advantages such as space saving and reduction in the number of parts.

There are various types of touch panels that detect contact with fingers, etc., but capacitive touch panels are one of the most popular touch panels for devices that require multi-point detection, such as smartphones. Be done. The capacitance type touch panel is provided with, for example, a matrix-like electrode pattern in the detection surface, and is adapted to detect a change in capacitance at a position where it is in contact with a finger or the like.

Furthermore, in recent years, in addition to smartphones, tablet-type image display devices and notebook computers are also equipped with touch panels, and their applications are expected to expand as mobile information terminals.

As a transparent conductive layer of a touch panel, a technique using silver nanowires or copper nanowires is being studied. This technique has an advantage that the transmittance can be increased and the film can be thinned as compared with the conventional conductive layer using an ITO (indium tin oxide) electrode.

However, the transparent conductive layer using silver nanowires or copper nanowires is compared with the conductive layer using ITO electrodes when the contact with a finger or a touch pen (hereinafter, also referred to as keystroke) is repeated many times. There is a problem that the transparent conductive layer may be deteriorated and the durability against keystrokes is insufficient.

On the other hand, as the base material of the touch panel, a glass base material has been conventionally used because the process temperature at the time of forming the transparent conductive layer is relatively high. A touch panel using a glass base material has high durability for touch panel production, but it is difficult to make it thin, and there is a problem that the function is stopped due to damage during transportation and glass breakage during operation of a touch panel-equipped terminal. ..

In order to solve the above problems, it has been considered to replace the conductive member using a glass base material with a conductive film using a transparent resin base material.

Since the polyimide film is excellent in heat resistance and bending resistance and has a high elastic modulus, it is conceivable to use it as a transparent conductive film base material for a touch panel.

In order to obtain a transparent polyimide film, various methods have been proposed for improving the transparency by changing the chemical structure of the polyimide (see, for example, Patent Document 1).
However, it is difficult to obtain a sufficiently transparent polyimide film only by changing the chemical structure of the polyimide, and further improvement is required.

When producing a film from polyimide, casting film formation using a high boiling point organic solvent is usually performed. However, when a polyimide film is produced using a high boiling point solvent, there is a problem that the high boiling point organic solvent or the like is easily decomposed and reacted during high temperature treatment to cause coloring.

Therefore, it is conceivable to use a compound that is easily dissolved in a low boiling point organic solvent as polyimide and cast film formation at a low temperature.

The present inventors have studied various methods for casting and forming a film at a low temperature by using a compound that is easily dissolved in a low boiling point organic solvent as polyimide. In this case, it becomes easier to obtain a transparent polyimide with less coloring, but when the polyimide film is used as the base material of the transparent conductive film, there is a problem that the durability against the above-mentioned keystroke is insufficient. all right. In particular, it has been found that there is a new problem that the durability against keystrokes varies greatly depending on whether the front surface or the back surface of the polyimide film is brought into contact with the transparent conductive layer.

Therefore, it has been difficult to stably produce a transparent polyimide film having good durability against keystrokes when used as a base material of a transparent conductive film.

Japanese Unexamined Patent Publication No. 2000-53767

The present invention has been made in view of the above problems and situations, and the problems to be solved thereof are good transparency, good durability against keystrokes when used as a base material of a transparent conductive film, and little variation in durability. The purpose is to provide a polyimide film. Another object of the present invention is to provide a method for producing the polyimide film. Further, the present invention provides a transparent conductive film using the polyimide film and a touch panel.

In order to solve the above-mentioned problems according to the present invention, in the process of examining the cause of the above-mentioned problems, a specific polyimide is used and the elastic modulus of the surface of the polyimide film is set within a specific range, so that the transparency is improved. The present invention has been made by finding that a polyimide film having good durability against keystrokes when used as a base material of a transparent conductive film and having little variation in durability can be obtained. Further, they have found that a touch panel having good durability against keystrokes can be stably manufactured by manufacturing a polyimide film by a specific manufacturing method and using it as a base material of a conductive film of a touch panel, and have reached the present invention.

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

A polyimide film containing 1 to 50 g of polyimide dissolved in 100 g of dichloromethane at 1.25 ° C., wherein the surface elastic modulus of one surface (A) of the polyimide film and the surface elasticity of the other surface (B) polyimide film difference rate is Ri der less 2 GPa, and characterized that you containing a boiling point of within the range of 80 ° C. or less of the organic solvent in the 0.1 to 2.0 g / ^{m 2.}

2 . A method for producing a polyimide film for producing the polyimide film according to the first item , wherein a dope containing the polyimide and an organic solvent having a boiling point of 80 ° C. or lower is prepared, and the dope is cast on a support. In the step of forming the film, peeling the film from the support, and drying the peeled film, and peeling the film from the support, the boiling point is 80 ° C. or lower. A method for producing a polyimide film, which comprises peeling the organic solvent in a state where the residual solvent amount of the organic solvent is in the range of 5 to 40% by mass or in the range of 100 to 200% by mass.

3 . A transparent conductive film having the polyimide film according to the first item and a transparent conductive layer.

4 . A touch panel comprising the transparent conductive film according to the third item.

According to the above means of the present invention, it is possible to provide a polyimide film having good transparency, good durability against keystrokes when used as a base material of a transparent conductive film, and little variation in durability. Further, a method for producing the polyimide film can be provided.

Although the mechanism of expression or mechanism of action of the effects of the present invention has not been clarified, it is inferred as follows.

In the production of a normal polyimide film, it is necessary to use a high boiling point organic solvent and perform high temperature treatment at the time of casting film formation. Therefore, when the film is heated, the high boiling point organic solvent and the polyimide resin are decomposed and reacted, and coloring is likely to occur. However, the polyimide dissolved in the range of 1 to 50 g with respect to 100 g of dichloromethane at 25 ° C. is easily dissolved in an organic solvent having a low boiling point, so that it is easy to dry at a low temperature. Therefore, coloring due to high temperature treatment is likely to be reduced.

However, when an organic solvent having a low boiling point is used, the organic solvent is easily vaporized, so that only the heated surface of the casting film is easily vaporized and cured. At that time, under normal casting film conditions, the drying condition of the polyimide film cast on the support is different on the support side (hereinafter referred to as the B side) and the air side (hereinafter referred to as the A side). Since they are different, it is presumed that a difference in elastic value is likely to occur between the A-side surface and the B-side surface, and fine irregularities are likely to occur due to shrinkage of the casting film surface. If there are fine irregularities on the surface, the durability against keystrokes when used as a base material for a transparent conductive film deteriorates, so it is presumed that repeated keystrokes are likely to cause poor contact. In addition, it is presumed that there will be variations during manufacturing because the durability against keystrokes differs depending on whether the conductive layer side is installed on the surface with fine irregularities or the conductive layer is installed on the opposite surface. are doing.

In the present invention, in the step of peeling the film from the support, it is preferable that the film is peeled off in a state where the residual solvent amount of the organic solvent having a boiling point of 80 ° C. or lower is 5 to 40% by mass or 100 to 200% by mass. .. Under the above-mentioned production conditions, a transparent polyimide film having a small difference in elastic modulus between the A-side and the B-side was obtained. Further, the polyimide film produced in this manner is less likely to generate fine irregularities due to shrinkage of the surface of the cast film. Therefore, when the film is used as a base material for a transparent conductive film, it is presumed that fine irregularities are less likely to occur due to shrinkage of the surface of the cast film, and durability against keystrokes and manufacturing stability are improved. are doing.

Schematic cross-sectional view showing an example of the configuration of the transparent conductive film of the present invention. The figure which showed typically the example of the doping preparation process, the casting process and the drying process of the solution casting film forming method preferable for this invention. Schematic cross-sectional view of a display device provided with an example of the configuration of the touch panel of the present invention.

The polyimide film of the present invention is a polyimide film containing 1 to 50 g of polyimide dissolved in 100 g of dichloromethane at 25 ° C., and the surface elastic modulus of one surface (A) of the polyimide film and the other surface ( difference in surface modulus of B) is Ri der less 2 GPa, and characterized that you containing a boiling point of within the range of 80 ° C. or less of the organic solvent in the 0.1 to 2.0 g / ^{m 2.} This feature is technical feature common to the invention according to the following embodiments.

As a method for producing a polyimide film for producing the polyimide film of the present invention, there is a step of preparing a dope containing the polyimide and an organic solvent having a boiling point of 80 ° C. or lower, and the dope is cast on a support to form a film. In the step of peeling the film from the support, which includes a step of forming, a step of peeling the film from the support, and a step of drying the peeled film, a residual solvent of an organic solvent having a boiling point of 80 ° C. or lower is included. The flatness of the film surface is good when the amount is peeled off in the range of 5 to 40% by mass or in the range of 100 to 200% by mass, and when used as the base material of the transparent conductive film of the touch panel. , It is preferable from the viewpoint of good transparency and good durability against keystrokes.

Further, a transparent conductive film having the polyimide film of the present invention and a transparent conductive layer, and a touch panel provided with the transparent conductive film are preferable from the viewpoints of good durability against keystrokes and little variation in the durability.

Hereinafter, the present invention, its constituent elements, 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 the value are included as the lower limit value and the upper limit value.

<Overview of the polyimide film of the present invention>
The polyimide film of the present invention is a polyimide film containing a polyimide (hereinafter, also referred to as soluble polyimide) that is dissolved in a range of 1 to 50 g with respect to 100 g of dichloromethane at 25 ° C., and is one surface of the polyimide film. a surface elastic modulus (a), the difference is der following 2GPa the surface elastic modulus of the other surface (B) is, and a boiling point of a 80 ° C. or less of the organic solvent in the 0.1 to 2.0 g / ^{m 2} It contains in the range.

The polyimide film of the present invention preferably contains polyimide as a main component. The inclusion of polyimide as a main component means that the total amount of polyimide in the film is 50% by mass or more. It is preferably 80% by mass or more. When the total amount of polyimide in the film is 50% by mass or more, it is preferable from the viewpoint of improving bending resistance, heat resistance, and elastic modulus.

<Polyimide>
The polyimide according to the present invention is a resin having an imide structure (hereinafter, also referred to as a polyimide resin), and is a resin containing an imide bond in a repeating unit. The polyimide is preferably formed from a diamine or a derivative thereof and an acid anhydride or a derivative thereof.

(1) Polyimide resin having a structure represented by the formula (1.1) As a polyimide that can be used in the present invention, a polyimide having a repeating unit represented by the following formula (1.1) (hereinafter, hereinafter, Polyimide (A)) is preferable.

式（１．１）中、Ｒは、芳香族炭化水素環若しくは芳香族複素環、又は、炭素数４〜３９の４価の脂肪族炭化水素基若しくは脂環式炭化水素基を表す。Ａは、炭素数２〜３９の２価の脂肪族炭化水素基、脂環式炭化水素基、芳香族炭化水素基、又はこれらの組み合わせからなる基を表し、結合基として、−Ｏ−、−ＳＯ_２−、−ＣＯ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−、−ＯＳｉ（ＣＨ_３）_２−、−Ｃ_２Ｈ_４Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも一つの基を含有していても良い。

In the formula (1.1), R represents an aromatic hydrocarbon ring or an aromatic heterocycle, or a tetravalent aliphatic hydrocarbon group having 4 to 39 carbon atoms or an alicyclic hydrocarbon group. A represents a divalent aliphatic hydrocarbon group having 2 to 39 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a group consisting of a combination thereof, and as a bonding group, -O-,- At least one selected from the group consisting of SO _2- , -CO-, -CH _2- , -C (CH ₃ ) _2- , -OSi (CH ₃ ) _2- , -C ₂ H ₄ O- and -S- It may contain one group.

Examples of the aromatic hydrocarbon ring represented by R include a fluorene ring, a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, a naphthalene ring, a triphenylene ring, o-. Terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronen ring, fluorantrene ring, naphthalene ring, pentacene ring, perylene ring, pentaphene ring, picene ring, pyrene ring, pyranthrene ring, anthra entre Benzene ring and the like.

Similarly, examples of the aromatic heterocycle represented by R include a silol 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 oxadi ring. Azol 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 ( Any one or more of the carbon atoms that make up the carbazole ring are replaced by nitrogen atoms), any one of the carbon atoms that make up the dibenzosilol ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or dibenzofuran ring. Rings in which one or more are replaced by nitrogen atoms, benzodifuran ring, benzodithiophene ring, aclysine ring, benzoquinoline ring, phenazine ring, phenanthridin ring, phenanthroline ring, cyclazine ring, kindrin ring, tepenidin ring, quinindrin ring, triphenodi Thiadine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafran ring, anthradifuran ring, anthrathiophene ring, anthrazi ring Examples thereof include a thiophene ring, a thiantolen ring, a phenoxatiin ring, a dibenzocarbazole ring, an indolocarbazole ring, and a dithienobenzene ring.

Examples of the tetravalent aliphatic hydrocarbon group having 4 to 39 carbon atoms represented by R include butane-1,1,4,4-triyl group and octane-1,1,8,8-triyl group. Examples include groups such as decane-1,1,10,10-triyl groups.

Examples of the tetravalent alicyclic hydrocarbon group having 4 to 39 carbon atoms represented by R include cyclobutane-1,2,3,4-tetrayl group and cyclopentane-1,2,4,5. -Tetrayl group, cyclohexane-1,2,4,5-tetrayl group, bicyclo [2.2.2] octo-7-en-2,3,5,6-tetrayl group, bicyclo [2.2.2] Octane-2,3,5,6-tetrayl group, 3,3', 4,4'-dicyclohexyltetrayl group, 3,6-dimethylcyclohexane-1,2,4,5-tetrayl group, 3,6- Examples thereof include groups such as diphenylcyclohexane-1,2,4,5-tetrayl groups.

Examples of the divalent aliphatic hydrocarbon group having 2 to 39 carbon atoms having or not having the above-mentioned bonding group represented by A include a group represented by the following structural formula.

上記構造式において、ｎは、繰り返し単位の数を表し、１〜５が好ましく、１〜３がより好ましい。また、Ｘは、炭素数１〜３のアルカンジイル基、つまり、メチレン基、エチレン基、トリメチレン基、プロパン−１，２−ジイル基であり、メチレン基が好ましい。

In the above structural formula, n represents the number of repeating units, preferably 1 to 5, and more preferably 1 to 3. Further, 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.

Examples of the divalent alicyclic hydrocarbon group having 2 to 39 carbon atoms having or not having the above-mentioned bonding group represented by A include a group represented by the following structural formula.

Ａで表される上記結合基を有する又は有さない炭素数２〜３９の２価の芳香族炭化水素基としては、例えば、下記構造式で表される基が挙げられる。

Examples of the divalent aromatic hydrocarbon group having 2 to 39 carbon atoms having or not having the above-mentioned bonding group represented by A include a group represented by the following structural formula.

Ａで表される脂肪族炭化水素基、脂環式炭化水素基及び芳香族炭化水素基の組み合わせからなる基としては、例えば、下記構造式で表される基が挙げられる。

Examples of the group composed of a combination of an aliphatic hydrocarbon group represented by A, an alicyclic hydrocarbon group and an aromatic hydrocarbon group include a group represented by the following structural formula.

Ａで表される基としては、結合基を有する炭素数２〜３９の２価の芳香族炭化水素基、又は該芳香族炭化水素基と脂肪族炭化水素基の組み合わせであることが好ましく、特に、以下の構造式で表される基が好ましい。

The group represented by A is preferably a divalent aromatic hydrocarbon group having a bonding group and having 2 to 39 carbon atoms, or a combination of the aromatic hydrocarbon group and an aliphatic hydrocarbon group, particularly preferably. , A group represented by the following structural formula is preferable.

前記式（１．１）のポリイミドは、芳香族、脂肪族若しくは脂環式テトラカルボン酸又はその誘導体と、ジアミン又はその誘導体とを反応させてポリアミド酸を調製し、当該ポリアミド酸をイミド化させることにより得られる。

The polyimide of the formula (1.1) is prepared by reacting an aromatic, aliphatic or alicyclic tetracarboxylic acid or a derivative thereof with a diamine or a derivative thereof to prepare a polyamic acid, and the polyamic acid is imidized. Obtained by

Examples of the derivative of the aliphatic or alicyclic tetracarboxylic acid include aliphatic or alicyclic tetracarboxylic acid esters, aliphatic or alicyclic tetracarboxylic dianhydride and the like. Of the aliphatic or alicyclic tetracarboxylic acid or its derivative, an alicyclic tetracarboxylic dianhydride is preferable.

Here, the derivative is a compound that can be changed to an aliphatic or alicyclic tetracarboxylic acid. For example, in the case of an aliphatic tetracarboxylic acid dianhydride, a compound having two carboxy groups instead of the anhydride. , A compound in which one or both of these two carboxy groups are esterified, or an acid chloride in which one or both of these two carboxy groups are chlorinated is preferably used.

By using such an acyl compound, a polyimide film having high heat resistance and excellent optical properties and less coloring (yellowing) can be obtained.

Examples of the aliphatic tetracarboxylic acid include 1,2,3,4-butanetetracarboxylic acid. Examples of the alicyclic tetracarboxylic acid include 1,2,3,4-cyclobutanetetracarboxylic dian, 1,2,4,5-cyclopentanetetracarboxylic dian, and 1,2,4,5-cyclohexanetetracarboxylic dian. , Bicyclo [2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic acid, Bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, etc. Can be mentioned.

Examples of the aliphatic tetracarboxylic acid esters include monoalkyl esters, dialkyl esters, trialkyl esters, and tetraalkyl esters of the above aliphatic tetracarboxylic acids. Examples of the alicyclic tetracarboxylic acid ester include monoalkyl ester, dialkyl ester, trialkyl ester and tetraalkyl ester of the alicyclic tetracarboxylic acid. The alkyl group moiety is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.

Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride. Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclopentanetetracarboxylic dianhydride, 1,2. , 4,5-Cyclohexanetetracarboxylic dianhydride, Bicyclo [2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, Bicyclo [2.2.2] Examples thereof include octane-2,3,5,6-tetracarboxylic dianhydride and 2,3,5-tricarboxycyclopentylacetic acid dianhydride. Particularly preferred is 1,2,4,5-cyclohexanetetracarboxylic dianhydride. In general, in polyimide containing an aliphatic diamine as a constituent component, polyamic acid and diamine, which are intermediate products, form a strong salt, so that a solvent having a relatively high salt solubility (for example, cresol) is used to increase the molecular weight. , N, N-dimethylacetamide, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) are preferably used. However, even in the case of polyimide containing an aliphatic diamine as a constituent component, when 1,2,4,5-cyclohexanetetracarboxylic dianhydride is used as a constituent component, the polyamic acid and the diamine salt are bound by a relatively weak bond. Therefore, it is easy to increase the molecular weight, and it is easy to obtain a flexible film.

Examples of the aromatic tetracarboxylic acid include 4,4'-biphthalic acid anhydride, 4,4'-(hexafluoroisopropyridene) diphthalic acid anhydride, and 2,3,3', 4'-biphenyltetracarboxylic acid. Dianoxide, 4,4'-oxydiphthalic anhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, 4- (2,5-dioxotetracarboxylic dianhydride) -1, 2,3,4-Tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, 3,3', 4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,4'-oxydiphthalic acid anhydride, 3,4 , 9,10-Perylenetetracarboxylic dianhydride (Pigment Red 224), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 2,2-bis (4- (3,4-dicarboxyphenoxy) ) Phenyl) Propane dianhydride, 9,9-bis (3,4-dicarboxyphenyl) fluorene, 9,9-bis [4- (3,4-dicarboxyphenoxy) -phenyl] fluorene anhydride, etc. Be done.

In addition, for example, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, Tricyclo [6.4.0.02,7] dodecane-1,8: 2,7-tetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene- 1,2-Dicarboxylic acid anhydride and the like can be used.

Further, an acid anhydride having a fluorene skeleton or a derivative thereof may be used. It has the effect of improving the coloring peculiar to polyimide. Examples of the acid anhydride having a fluorene skeleton include 9,9-bis (3,4-dicarboxyphenyl) fluorene dianhydride and 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl. ] Fluorenic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-phenylphenyl] fluorenic dianhydride and the like can be used.

As the aromatic, aliphatic or alicyclic tetracarboxylic acid or a derivative thereof, one type may be used alone, or two or more types may be used in combination. Further, other tetracarboxylic dians or derivatives thereof (particularly dianhydride) may be used in combination as long as the solvent solubility of the polyimide, the flexibility of the polyimide film, the thermocompression bonding property, and the transparency are not impaired.

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-dicarboxyphenyl) 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-dicarboxyphenyl) Aromatic tetracarboxylic acids such as ethane, bis (2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane and derivatives thereof (particularly dianhydride); ethylenetetracarboxylic acid and the like. Examples thereof include aliphatic tetracarboxylic acids having 1 to 3 carbon atoms and derivatives thereof (particularly dianhydride).

As the acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanedianehydride or biphenyltetracarboxylic dianhydride is excellent in transparency and heat due to heat shrinkage. It 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 80 to 100 mol%, based on all the repeating units. Is 90-100 mol%. The number of repeating units of the formula (1.1) in one molecule of polyimide (A) is 10 to 2000, preferably 20 to 200, and the glass transition temperature is further 230 to 350 ° C. in this range. It is preferably 250 to 330 ° C., and more preferably 250 to 330 ° C.

As the diamine or a derivative thereof, for example, an aromatic diamine or an isocyanic acid ester is preferable, and an aromatic diamine is preferable.

The diamine or a derivative thereof used in the present invention may be any of aromatic diamines, aliphatic diamines and mixtures thereof, and aromatic diamines are preferable from the viewpoint of suppressing whitening of the polyimide film.

In the present invention, the "aromatic diamine" represents a diamine in which an amino group is directly bonded to an aromatic ring, and an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or the like is part of the structure thereof. It may contain a substituent (for example, a halogen atom, a sulfonyl group, a carbonyl group, an oxygen atom, etc.). The "aliphatic diamine" represents a diamine in which an amino group is directly bonded to an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and an aromatic hydrocarbon group or other substituent (a part of the structure thereof) is used. For example, it may contain a halogen atom, a sulfonyl group, a carbonyl group, an oxygen atom, etc.).

Examples of aromatic diamines include, for example, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, benzidine, o-trizine, m-trizine, bis (trifluoromethyl). Benzidine, Octafluorobenzidine, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl , 3,3'-difluoro-4,4'-diaminobiphenyl, 2,6-diaminonaphthalene, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4' −Diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 4,4′-diaminobenzophenone, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 2, 2-Bis (4- (2-methyl-4-aminophenoxy) phenyl) propane, 2,2-bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) propane, 2,2-bis ( 4- (4-Aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (2-methyl-4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (2,6) -Dimethyl-4-aminophenoxy) phenyl) hexafluoropropane, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (2-methyl-4-aminophenoxy) biphenyl, 4,4' -Bis (2,6-dimethyl-4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, bis (4- (4-aminophenoxy) phenyl) sulfone, bis (4- (2) −Methyl-4-aminophenoxy) phenyl) sulfone, bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) sulfone, bis (4- (4-aminophenoxy) phenyl) ether, bis (4-) (2-Methyl-4-aminophenoxy) phenyl) ether, bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) ether, 1,4-bis (4-aminophenoxy) benzene, 1,4 -Bis (2-methyl-4-aminophenoxy) benzene, 1,4-bis (2,6-dimethyl-4-aminophenoxy) benzene, 1,3-bis (4-) Aminophenoxy) benzene, 1,3-bis (2-methyl-4-aminophenoxy) benzene, 1,3-bis (2,6-dimethyl-4-aminophenoxy) benzene, 2,2-bis (4-amino) Phenyl) propane, 2,2-bis (2-methyl-4-aminophenyl) propane, 2,2-bis (3-methyl-4-aminophenyl) propane, 2,2-bis (3-ethyl-4-aminophenyl) propane Aminophenyl) propane, 2,2-bis (3,5-dimethyl-4-aminophenyl) propane, 2,2-bis (2,6-dimethyl-4-aminophenyl) propane, 2,2-bis (4) -Aminophenyl) Hexafluoropropane, 2,2-bis (2-methyl-4-aminophenyl) hexafluoropropane, 2,2-bis (2,6-dimethyl-4-aminophenyl) hexafluoropropane, α, α'-bis (4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (2-methyl-4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (2) , 6-Dimethyl-4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (3-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (2-methyl-4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (2,6-dimethyl-4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (3-aminophenyl) -1,3-diisopropylbenzene, 1,1-bis (4-aminophenyl) cyclopentane, 1,1-bis (2-) Methyl-4-aminophenyl) cyclopentane, 1,1-bis (2,6-dimethyl-4-aminophenyl) cyclopentane, 1,1-bis (4-aminophenyl) cyclohexane, 1,1-bis (2) -Methyl-4-aminophenyl) cyclohexane, 1,1-bis (2,6-dimethyl-4-aminophenyl) cyclohexane, 1,1-bis (4-aminophenyl) 4-methyl-cyclohexane, 1,1- Bis (4-aminophenyl) norbornan, 1,1-bis (2-methyl-4-aminophenyl) norbornan, 1,1-bis (2,6-dimethyl-4-aminophenyl) norbornan, 1,1-bis (4-Aminophenyl) Adamantane, 1,1-bis (2-methyl-4-aminophenyl) Adamantane, 1,1-bis (2,6-dimethyl-4-aminophenyl) Adamantane, 1,4-phenylenediamine, 3,3'-diaminobenzophenone, 2,2-bis (3-aminophenyl) hexafluoropropane , 3-Aminobenzylamine, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 2,2-bis [4- (4- (4- (4- (4-) 4-) Aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] sulfone, 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene, bis (2-aminophenyl) sulfide , Bis (4-aminophenyl) sulfide, 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 3,3'-diaminodiphenylmethane, 4 , 4'-ethylenedianiline, 4,4'-methylenebis (cyclohexylamine), 4,4'-methylenebis (2,6-diethylaniline), 4,4'-methylenebis (2-methylcyclohexylamine), etc. Be done.

Examples of the aliphatic diamine include ethylenediamine, hexamethylenediamine, polyethylene glycol bis (3-aminopropyl) ether, polypropylene glycol bis (3-aminopropyl) ether, 1,3-bis (aminomethyl) cyclohexane, and 1,4. -Bis (aminomethyl) cyclohexane, m-xylylene diamine, p-xylylene diamine, 1,4-bis (2-amino-isopropyl) benzene, 1,3-bis (2-amino-isopropyl) benzene, isophorone Diamine, Norbornan Diamine, siloxane Diamine, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodicyclohexylmethane, 3 , 3', 5,5'-Tetramethyl-4,4'-diaminodicyclohexylmethane, 2,3-bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,5-bis (aminomethyl) -Bicyclo [2.2.1] heptane, 2,6-bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,2-bis (4,4'-diaminocyclohexyl) propane, 2,2 -Bis (4,4'-diaminomethylcyclohexyl) propane and the like can be mentioned.

Further, a diamine having a fluorene skeleton or a derivative thereof may be used for the purpose of improving the coloring peculiar to polyimide. For example, 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene, 9,9-bis [4- (4-aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-Aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3) -Methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino) -3-Ethylphenoxy) -3-Phenylphenyl] Fluolene and the like can be used.

Further, a diamine compound having a triazine mother nucleus represented by the following formula can be preferably used.

トリアジン母核を有する上記式のジアミン化合物において、Ｒ^１は水素原子又は炭素数１〜１２（好ましくは炭素数１〜１０、さらに好ましくは炭素数１〜６）のアルキル基又はアリール基を表し、Ｒ^２は炭素数１〜１２（好ましくは炭素数１〜１０、さらに好ましくは炭素数１〜６）のアルキル基又はアリール基を表し、Ｒ^１とＲ^２は異なっていても良く、同じであっても良い。

In the diamine compound of the above formula having a triazine mother nucleus, R ¹ represents a hydrogen atom or an alkyl group or an aryl group having 1 to 12 carbon atoms (preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms). R ² represents an alkyl group or an aryl group having 1 to 12 carbon atoms (preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), and R ¹ and R ² may be different and are the same. You may.

Specific examples of the alkyl group or aryl group having 1 to 12 carbon atoms of R ¹ and R ² include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, phenyl, benzyl, naphthyl, methylphenyl and biphenyl. And so on.

The aminoanilino group connected to the two NH groups of triazine is 4-aminoanilino or 3-aminoanilino, which may be the same or different, but 4-aminoanilino is preferable.

Specific examples of the diamine compound having a triazine matrix and represented by the above formula include 2,4-bis (4-aminoanilino) -6-anilino-1,3,5-triazine and 2,4-bis ( 3-Aminoanilino) -6-anilino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-benzylamino-1,3,5-triazine, 2,4-bis (3-aminoanilino) ) -6-benzylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-naphthylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino)- 6-biphenylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-diphenylamino-1,3,5-triazine, 2,4-bis (3-aminoanilino) -6- Diphenylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-dibenzylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-di Naphthylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-N-methylanilino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-N -Methylnaphthylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-methylamino-1,3,5-triazine, 2,4-bis (3-aminoanilino) -6- Methylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-ethylamino-1,3,5-triazine, 2,4-bis (3-aminoanilino) -6-ethylamino -1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-dimethylamino-1,3,5-triazine, 2,4-bis (3-aminoanilino) -6-dimethylamino-1 , 3,5-Triazine, 2,4-bis (4-aminoanilino) -6-diethylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-dibutylamino-1,3 5-triazine, 2,4-bis (4-aminoanilino) -6-amino-1,3,5-triazine, 2,4-bis (3-aminoanilino) -6-amino-1,3,5-triazine, etc. Can be mentioned.

Examples of the isocyanic acid ester which is a diamine derivative include diisocyanate obtained by reacting the above aromatic or aliphatic diamine with phosgene.

In addition, examples of other diamine derivatives include diaminodisilanes, and examples thereof include trimethylsilylated aromatic or aliphatic diamines obtained by reacting the above aromatic or aliphatic diamines with chlorotrimethylsilane.

As the diamine, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl is preferable from the viewpoint of excellent transparency and easy heat correction by heat shrinkage.

The above diamines and their derivatives may be arbitrarily mixed and used, but the amount of diamines in them is preferably 50 to 100 mol%, more preferably 80 to 100 mol%.

(1.3) Synthesis method and imidization of polyamic acid (1.3.1) Synthesis of polyamic acid Polyamic acid contains at least one of the tetracarboxylic acids and at least one of the diamines in a suitable solvent. It is obtained by polymerizing the types.

The polyamic acid ester is formed by diesterifying the tetracarboxylic acid dianhydride with an alcohol such as methanol, ethanol, isopropanol, or n-propanol, and the obtained diester is prepared in an appropriate solvent. It can be obtained by reacting with a diamine compound. Further, the polyamic acid ester can also be obtained by esterifying the carboxylic acid group of the polyamic acid obtained as described above by reacting with the alcohol as described above.

The reaction between the tetracarboxylic dianhydride and the diamine compound can be carried out under conventionally known conditions. The order and method of adding the tetracarboxylic dianhydride and the diamine compound are not particularly limited. For example, polycarboxylic acid can be obtained by sequentially adding 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, based on 1 mol of the tetracarboxylic dianhydride. On the other hand, it is usually 1.2 mol or less, preferably 1.1 mol or less. By setting the amount of the diamine compound in such a range, the yield of the obtained polyamic acid can be improved.

The concentrations of the tetracarboxylic dianhydride and the diamine compound in the solvent are 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, based on the total amount of the solution, while usually 70. It is mass% or less, preferably 30 mass% or less. By setting the amount of the reaction substrate in such a range, polyamic acid can be obtained at low cost and in good yield.

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

Examples of the polymerization solvent used in this reaction include hydrocarbon solvents such as hexane, cyclohexane, heptane, benzene, toluene, xylene and mesityrene; 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- Amid solvents such as dimethylacetamide and N-methyl-2-pyrrolidone; aproton polar solvents such as dimethylsulfoxide and γ-butyrolactone; heterocyclic solvents such as pyridine, picolin, lutidine, quinoline and isoquinolin; Such as phenolic solvent, etc., but are not particularly limited. As the polymerization solvent, only one kind may be used, or two or more kinds of solvents may be mixed and used.

As the terminal group of the polyamic acid, an acid anhydride group and an amino group can be arbitrarily selected by excessively using either one of the tetracarboxylic acid dianhydride and the diamine compound at the time of the polymerization reaction.

When the terminal group is an acid anhydride terminal, the acid anhydride terminal may be left as it is without further treatment, or it may be hydrolyzed to obtain a dicarboxylic acid. Further, an alcohol having 4 or less carbon atoms may be used as an ester. Further, the end 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, phenylisocyanate, xylylene isocyanate, cyclohexylisocyanate. , Methylphenyl isocyanate, trifluoromethylphenyl isocyanate and the like.

When the terminal group is an amine terminal, it is possible to prevent the amino group from remaining at the terminal by sealing the terminal amino group with a monofunctional acid anhydride. The acid anhydride used here is not particularly limited as long as it is a monofunctional acid anhydride that becomes a dicarboxylic acid or a tricarboxylic acid when hydrolyzed. For example, maleic anhydride, methylmaleic anhydride, dimethylmaleic anhydride, succinic anhydride, norbornendicarboxylic acid anhydride, 4- (phenylethynyl) phthalic anhydride, 4-ethynylphthalic anhydride, phthalate. Acid anhydride, methylphthalic anhydride, dimethylphthalic anhydride, trimellitic anhydride, naphthalenedicarboxylic acid anhydride, 7-oxabicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride, bicyclo [2.2.1] Heptane-2,3-dicarboxylic acid anhydride, bicyclo [2.2.2] Octa-5-ene-2,3-dicarboxylic acid anhydride, 4-oxatricyclo [5.2] .2.0 ^2,6 ] Undecane-3,5-dione, octahydro-1,3-dioxoisobenzofuran-5-carboxylic acid, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, dimethylcyclohexanedicarboxylic Acid anhydrides, 1,2,3,6-tetrahydrophthalic anhydrides, methyl-4-cyclohexene-1,2-dicarboxylic acid anhydrides and the like can be mentioned.

(1.3.2) Imidization Method Here, the polyimide is a method of heating a polyamic acid solution to imidize the polyamic acid (thermal imidization method), or a ring-closing catalyst (imidization catalyst) in the polyamic acid solution. Can be obtained by a method of imidizing a polyamic acid by adding (chemical imidization method).

Further, a method of heating the polyamic acid solution to imidize the polyamic acid (thermal imidization method) or a method of adding a ring-closing catalyst (imidization catalyst) to the polyamic acid solution to imidize the polyamic acid (chemical imid). As for the conversion method), the reaction kettle for polymerizing the polyamic acid from the acid anhydride and the diamine may be continuously imidized in the reaction kettle.

In the thermal imidization method in a reaction vessel, the polyamic acid in the polymerization solvent is heat-treated in a temperature range of, for example, 80 to 300 ° C. for 0.1 to 200 hours to proceed with imidization. Further, the temperature range is preferably 150 to 200 ° C., and by setting the temperature to 150 ° C. or higher, imidization can be reliably advanced and completed, while by setting the temperature to 200 ° C. or lower, the solvent or the like can be used. It is possible to prevent an increase in resin concentration due to oxidation of unreacted raw materials and volatilization of a 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 co-boiling 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 the 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 promote 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 picolin, and other examples thereof include substitution or non-substituted or non-substituted amines. 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 a hydroxy group, and aromatic heterocyclic compounds, particularly 1,2. Lower alkyl imidazoles 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, substituted pyridines such as isoquinoline, 3,5-dimethylpyridine, 3,4-dimethylpyridine, 2,5-dimethylpyridine, 2,4-dimethylpyridine, 4-n-propylpyridine, p-toluene A sulfonic acid or the like can be preferably used. The amount of the ring-closing catalyst added is preferably 0.01 to 2 times equivalent, particularly about 0.02 to 1 times equivalent with respect to the amic acid unit of the polyamic acid. By using a ring closure catalyst, the physical properties of the obtained polyimide, particularly elongation and breaking resistance, may be improved.

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

The polyimide solution imidized in the reaction vessel in this way is advantageous because the molecular weight is less likely to decrease due to hydrolysis over time as compared with the polyimide solution.
Further, since the imidization reaction has proceeded in advance, for example, in the case of polyimide having an imidization rate of 100%, imidization on the web becomes unnecessary and the drying temperature can be lowered.

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

According to this method, it is possible to use different types of the polymerization solvent and the casting solvent, and by selecting the optimum solvent for each, it is possible to further bring out the performance of the polyimide film.

For example, in order to increase the molecular weight of polyamic acid, it is polymerized and ring-closed with dimethylacedamide, solidified with methanol, dried, then made into a solution with an additive added with dichloromethane, and then cast and dried. As a result, high molecular weight and low temperature drying become possible.

When dichloromethane is used as the solvent, it can be used in combination with other solvents. Auxiliary solvents such as tetrahydrofuran (THF), dioxolane, cyclohexanone, cyclopentanone, γ-butyrolactone, ethanol, methanol, butanol, and iropropanol can also be used as appropriate.

(1.4) Other Polyimide In addition to the above-mentioned polyimide, a polyimide containing atoms such as phosphorus, silicon, and sulfur can also be used.

For example, as the polyimide containing phosphorus, the polyimides described in paragraphs [0010]-[0021] of JP2011-74209A and paragraphs [0011]-[0025] of JP2011-074177 are used. Can be done.

As the polyimide containing silicon, the polyimide obtained by imidizing the polyimide precursor described in paragraphs [0030]-[0045] of JP2013-028996A can be used.

Examples of the polyimide containing sulfur include paragraphs [0009]-[0025] of JP2010-189322A, paragraphs [0012]-[0025] of JP2008-274234, and paragraphs of JP2008-274229. The polyimide obtained by imidizing the polyimide precursor described in [0012]-[0023] can be used.

In addition, the alicyclic polyimide described in paragraphs [0008]-[0012] of JP2009-256590 and paragraphs [0008]-[0012] of JP2009-256589 are preferably used. it can.

(2) Polyamide-imide The polyamide-imide used is a polyamide-imide containing a tricarboxylic acid or tetracarboxylic acid, a dicarboxylic acid as an acid component, and a diamine as an amine component as a constituent unit.

The polyamide-imide used has an acid component as an acid component.
a) Tricarboxylic acid; diphenyl ether-3,3', 4'-tricarboxylic acid, diphenylsulfone-3,3', 4'-tricarboxylic acid, benzophenone-3,3', 4'-tricarboxylic acid, naphthalene-1,2 , 4-Tricarboxylic acid, monoanhydrides such as tricarboxylic acids such as butane-1,2,4-tricarboxylic acid, singles such as esterified products, or mixtures of two or more.

b) Tetracarboxylic acid; diphenylsulfone-3,3', 4,4'-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid , Naphthalene-1,4,5,8-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, dianhydride , Alone, such as an esterified product, or a mixture of two or more.

c) Dicarboxylic acid; adipic acid, azelaic acid, sebacic acid, dicarboxylic acid of cyclohexane-4,4'-dicarboxylic acid, and these monoanhydrides and esters.

As an amine component,
d) Amin component 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2 , 2'-diethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-diethoxy-4,4'-diaminobiphenyl, p-phenylenediamine, m −Phenylenediamine, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 3,4′-diaminobiphenyl, 3,3′ −Diaminobiphenyl, 3,3′-diaminobenzanilide, 4,4′-diaminobenzanilide, 4,4′-diaminobenzophenone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 2,6- Tolylene diamine, 2,4-tolylene diamine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 3, 3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, p-xylene diamine, m-xylene diamine, 2,2'-bis (4-aminophenyl) propane, 1,3-bis (3-aminophenoxy) benzene , 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- ( 4-Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] propane, 4,4'-bis (4-aminophenoxy) biphenyl , 4,4'-bis (3-aminophenoxy) biphenyl, tetramethylenediamine, hexamethylenediamine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, cyclohexane-1,4-diamine, diaminosiloxane, or corresponding Diisocyanate alone or a mixture of two or more.

In particular, as acid components, trimellitic anhydride (TMA), 3,3,4', 4'-benzophenonetetracarboxylic dianhydride (BTDA), and 3,3,4', 4'-biphenyltetracarboxylic acid. A polyamide imide resin polymerized with a raw material containing dianhydride (BPDA) and 1,5-naphthalenedi isocyanate (NDI) as an isocyanate component is preferable.

The molar ratio of the imide bond to the amide bond of the polyamide-imide is preferably 99/1 to 60/40 molar ratio, more preferably 99/1 to 75/25, and even more preferably 90/10 to 80/20. is there. When the molar ratio of the imide bond to the amide bond is 60/40 or more, the heat resistance, the moisture resistance reliability, and the heat resistance reliability are improved. Further, when it is 99/1 or less, the elastic modulus tends to be low, and the folding resistance characteristics and the bending characteristics tend to be improved.

(2.1) Polyamide-imide having a structure represented by the formula (2) as an essential component One preferred embodiment has a structure represented by the formula (2) as an essential component, and further formulas (3) and the formula. A polyamide-imide resin containing at least one structure selected from the group represented by (4) and (5) as a repeating unit in the molecular chain.

（Ｘは、酸素原子、ＣＯ、ＳＯ_２、又は、結合を表す。ｎは０又は１を表す。）

（Ｙは、酸素原子、ＣＯ、又はＯＯＣ−Ｒ−ＣＯＯを表す。ｎは０又は１を、Ｒは二価の有機基を表す。）

ここで、式（３）中、Ｘが、ＳＯ_２、又は、結合（ビフェニル結合）であること、又は、ｎ＝０であることが好ましい。更に好ましくは、Ｘが結合（ビフェニル結合）であること、又はｎ＝０であることである。式（４）中、Ｙは、ベンゾフェノン型（ＣＯ）、又は、結合型（ビフェニル結合）が好ましい。

(X represents an oxygen atom, CO, SO ₂ or a bond. N represents 0 or 1.)

(Y represents an oxygen atom, CO, or OOC-R-COO. N represents 0 or 1, and R represents a divalent organic group.)

Here, in the formula (3), it is preferable that X is SO ₂ or a bond (biphenyl bond), or n = 0. More preferably, X is a bond (biphenyl bond) or n = 0. In the formula (4), Y is preferably a benzophenone type (CO) or a bound type (biphenyl bond).

In one preferred embodiment, formula (2) is a repeating unit from trimellitic anhydride and 1,5-naphthalenediocyanate, formula (3) is a repeating unit from terephthalic acid and 1,5-naphthalenediocyanate, formula (4). Is a repeating unit from biphenyltetracarboxylic dianhydride or benzophenonetetracarboxylic dianhydride and 1,5-naphthalenediocyanate, and the content ratio is formula (2) / {formula (3) + formula (4). + Formula (5)} = 1/99 to 40/60 molar ratio, and formula (3) / formula (4) = 10/90 to 90/10 molar ratio is preferable.

The higher the imidization rate, the more preferably the upper limit is 100%. The above-mentioned polyamide-imide resin can be synthesized by a usual method. For example, the isocyanate method, the amine method (acid chloride method, low temperature solution polymerization method, room temperature solution polymerization method, etc.) are used. The polyamide-imide 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 preferable. Also, industrially, it is preferable because the solution at the time of polymerization can be applied as it is.

(2.2) Polyamideimide having a structure represented by the formula (6) or the formula (7) As a preferable polyamide-imide resin, a compound containing the following formula (6) as a constituent unit can be preferably used. The compound having the structure represented by the formula (6) will be described below.

（式中、Ｒ_１はアリール基、シクロアルカン基であり、窒素、酸素、硫黄、ハロゲンを含んでもよい。）
（ポリアミドイミド樹脂のジアミン成分）
また、ジアミン成分としては、ｐ−フェニレンジアミン、ｍ−フェニレンジアミン、３，４′−ジアミノジフェニルエーテル、４，４′−ジアミノジフェニルエーテル、４，４′−ジアミノジフェニルスルホン、３，３′−ジアミノジフェニルスルホン、３，４′−ジアミノビフェニル、３，３′−ジアミノビフェニル、３，３′−ジアミノベンズアニリド、４，４′−ジアミノベンズアニリド、４，４′−ジアミノベンゾフェノン、３，３′−ジアミノベンゾフェノン、３，４′−ジアミノベンゾフェノン、２，６−トリレンジアミン、２，４−トリレンジアミン、４，４′−ジアミノジフェニルスルフィド、３，３′−ジアミノジフェニルスルフィド、４，４′−ジアミノジフェニルプロパン、３，３′−ジアミノジフェニルプロパン、３，３′−ジアミノジフェニルメタン、４，４′−ジアミノジフェニルメタン、Ｐ−キシレンジアミン、ｍ−キシレンジアミン、１，４−ナフタレンジアミン、１，５−ナフタレンジアミン、２，６−ナフタレンジアミン、２，７−ナフタレンジアミン、２，２′−ビス（４−アミノフェニル）プロパン、１，３−ビス（３−アミノフェノキシ）ベンゼン、１，３−ビス（４−アミノフェノキシ）ベンゼン、１，４−ビス（４−アミノフェノキシ）ベンゼン、２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン、ビス［４−（４−アミノフェノキシ）フェニル］スルホン、ビス［４−（３−アミノフェノキシ）フェニル］スルホン、ビス［４−（３−アミノフェノキシ）フェニル］プロパン、４，４′−ビス（４−アミノフェノキシ）ビフェニル、４，４′−ビス（３−アミノフェノキシ）ビフェニル、３，３′−ジメチル−４，４′−ジアミノビフェニル、４−メチル−１，３−フェニレンジアミン、３，３′−ジエチル−４，４′−ジアミノビフェニル、２，２′−ジメチル−４，４′−ジアミノビフェニル、２，２′−ジエチル−４，４′−ジアミノビフェニル、３，３′−ジメトキシ−４，４′−ジアミノビフェニル、３，３′−ジエトキシ−４，４′−ジアミノビフェニル、トランス−１，４−ジアミノシクロヘキサン、シス−１，４−ジアミノシクロヘキサン、１，４−ジアミノシクロヘキサン（トランス／シス混合物）、１，３−ジアミノシクロヘキサン、ジシクロヘキシルメタン−４，４′−ジアミン（トランス体、シス体、トランス／シス混合物）、イソホロンジアミン、１，４−シクロヘキサンビス（メチルアミン）、２，５−ビス（アミノメチル）ビシクロ〔２．２．１〕ヘプタン、２，６−ビス（アミノメチル）ビシクロ〔２．２．１〕ヘプタン、３，８−ビス（アミノメチル）トリシクロ〔５．２．１．０〕デカン、１，３−ジアミノアダマンタン、４，４′−メチレンビス（２−メチルシクロヘキシルアミン）、４，４′−メチレンビス（２−エチルシクロヘキシルアミン）、４，４′−メチレンビス（２，６−ジメチルシクロヘキシルアミン）、４，４′−メチレンビス（２，６−ジエチルシクロヘキシルアミン）、２，２−ビス（４−アミノシクロヘキシル）プロパン、２，２−ビス（４−アミノシクロヘキシル）ヘキサフルオロプロパン、１，３−プロパンジアミン、１，４−テトラメチレンジアミン、１，５−ペンタメチレンジアミン、１，６−ヘキサメチレンジアミン、１，７−ヘプタメチレンジアミン、１，８−オクタメチレンジアミン、１，９−ノナメチレンジアミンなどの単独、若しくは、２種以上の混合物、又は、これらに対応するジイソシアネートなどの単独、若しくは、２種以上の混合物をジアミン成分として用いることができる。

(In the formula, R ₁ is an aryl group or a cycloalkane group, and may contain nitrogen, oxygen, sulfur, and halogen.)
(Diamine component of polyamide-imide resin)
The diamine components include p-phenylenediamine, m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, and 3,3'-diaminodiphenyl sulfone. , 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 3,3'-diaminobenzanilide, 4,4'-diaminobenzanilide, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone , 3,4'-diaminobenzophenone, 2,6-tolylene diamine, 2,4-tolylene diamine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl Propane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, P-xylene diamine, m-xylene diamine, 1,4-naphthalenediamine, 1,5-naphthalenediamine , 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2'-bis (4-aminophenyl) propane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenyl) Aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, Bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] propane, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3) -Aminophenoxy) Biphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4-methyl-1,3-phenylenediamine, 3,3'-diethyl-4,4'-diaminobiphenyl, 2,2 ′ -Dimethyl-4,4′-diaminobiphenyl, 2,2′-diethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-diethoxy-4 , 4'-diaminobiphenyl, trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, 1,4-diaminocyclohexane (trans / cis mixture), 1,3-diaminocyclohexane, dicyclohexylmethane-4, 4'-diamine (trans-form, cis-form, trans / cis mixture) , Isophoronediamine, 1,4-cyclohexylaminebis (methylamine), 2,5-bis (aminomethyl) bicyclo [2.2.1] heptane, 2,6-bis (aminomethyl) bicyclo [2.2.1] ] Heptane, 3,8-bis (aminomethyl) tricyclo [5.2.1.0] decane, 1,3-diaminoadamantan, 4,4'-methylenebis (2-methylcyclohexylamine), 4,4'- Methylenebis (2-ethylcyclohexylamine), 4,4'-methylenebis (2,6-dimethylcyclohexylamine), 4,4'-methylenebis (2,6-diethylcyclohexylamine), 2,2-bis (4-amino) Cyclohexyl) propane, 2,2-bis (4-aminocyclohexyl) hexafluoropropane, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-Heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, etc. alone, or a mixture of two or more, or the corresponding diisocyanate, etc. alone, or two. The above mixture can be used as a diamine component.

Preferably, 3,3'-dimethyl-4,4'-diaminobiphenyl, dicyclohexylmethane-4,4'-diamine (trans form, cis form, trans / cis mixture), 4,4'-diaminodiphenyl ether, p- A single or a mixture of two or more kinds of phenylenediamine, 4-methyl-1,3-phenylenediamine, etc., or a single or a mixture of two or more kinds of diisocyanates corresponding thereto may be used as a diamine component. it can.

More preferably, 3,3'-dimethyl-4,4'-diaminobiphenyl, dicyclohexylmethane-4,4'-diamine (trans form, cis form, trans / cis mixture), 4,4'-diaminodiphenyl ether, 4 -Methyl-1,3-phenylenediamine or the like alone or a mixture of two or more kinds, or a corresponding diisocyanate or the like alone or a mixture of two or more kinds can be used as a diamine component.

More preferably, 3,3'-dimethyl-4,4'-diaminobiphenyl, dicyclohexylmethane-4,4'-diamine (trans form, cis form, trans / cis mixture), 4-methyl-1,3-phenylene. A single diamine or a mixture of two or more kinds, or a corresponding diisocyanate or a mixture of two or more kinds can be used as a diamine component.

(Preferable combination of acid component and diamine component)
Among the above acid components and diamine components, the following components are based on the heat resistance, solvent resistance, and durability in the film forming process, and the heat resistance, surface smoothness, and transparency of the produced polyamide-imide film. Is preferably used.

As the acid component, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride can be used. A polyamide-imide resin containing cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride as an acid component can be used.

As the diamine component, at least one or two compounds selected from the group consisting of 3,3'-dimethyl-4,4'-diaminobiphenyl and 4-methyl-1,3-phenylenediamine, or 3,3 At least one or two compounds selected from the group consisting of ′ -dimethyl-4,4 ′-diisocyanate biphenyl (o-trizine diisocyanate) and 4-methyl-1,3-phenylenediocyanate (toluene diisocyanate). Can be used.

Further, as a preferable polyamide-imide resin, a compound containing a structure represented by the following formula (7) as a constituent unit can be used.

（式中、Ｒ_２、Ｒ_３はそれぞれ水素、炭素数１〜３のアルキル基又はアリール基を表し、窒素、酸素、硫黄、ハロゲンを含んでもよい。）
なお、全酸成分を１００モル％とした場合、例示した酸成分は５０モル％以上１００％以下含まれるのがよく、より好ましくは７０モル％以上１００％以下含まれるのがよい。また、全ジアミン成分を１００モル％とした場合、例示したジアミン成分は５０モル％以上１００％以下含まれるのがよく、より好ましくは７０モル％以上１００％以下含まれるがよい。これらの範囲であれば、フィルム化するプロセスでの耐熱性、耐久性がよく、得られるポリアミドイミドフィルムの耐熱性、表面平滑性、及び透明性が特に良くなる。

(In the formula, R ₂ and R ₃ represent hydrogen, an alkyl group having 1 to 3 carbon atoms or an aryl group, respectively, and may contain nitrogen, oxygen, sulfur, and halogen.)
When the total acid component is 100 mol%, the illustrated acid component is preferably contained in an amount of 50 mol% or more and 100% or less, and more preferably 70 mol% or more and 100% or less. When the total diamine component is 100 mol%, the illustrated diamine component is preferably contained in an amount of 50 mol% or more and 100% or less, and more preferably 70 mol% or more and 100% or less. Within these ranges, the heat resistance and durability in the film forming process are good, and the heat resistance, surface smoothness, and transparency of the obtained polyamide-imide film are particularly good.

The molecular weight of the polyamide-imide resin used is 0.3 to 2.5 cm ³ / g in logarithmic viscosity at 30 ° C. in N-methyl-2-pyrrolidone (polymer concentration 0.5 g / cm ³ ). Is preferable, and more preferably, it has a molecular weight corresponding to 0.5 to 2.0 cm ³ / g. If the logarithmic viscosity is 0.3 cm ³ / g or more, the mechanical properties will be sufficient when a molded product such as a film is formed. Further, when it is 2.0 cm ³ / g or less, the solution viscosity does not become too high, and the molding process becomes easy.

(1.3) Polyetherimide The polyetherimide used is a thermoplastic resin containing an aromatic nucleus bond and an imide bond in its structural unit, and is not particularly limited. Specifically, the following formula (8) ) Or a polyetherimide having a repeating unit having a structure represented by the following formula (9).

上記式（８）で表される構造の繰り返し単位を有するポリエーテルイミドは、ゼネラルエレクトリック社製の商品名「Ｕｌｔｅｍ １０００」（ガラス転移温度：２１６℃）、「Ｕｌｔｅｍ １０１０」（ガラス転移温度：２１６℃）、上記式（９）で表される構造の繰り返し単位を有するポリエーテルイミドは、「Ｕｌｔｅｍ ＣＲＳ５００１」（ガラス転移温度Ｔｇ２２６℃）、が挙げられ、そのほかの具体例として、三井化学株式会社製の商品名「オーラムＰＬ５００ＡＭ」（ガラス転移温度２５８℃）などが挙げられる。

Polyetherimides having a repeating unit having a structure represented by the above formula (8) are trade names "Ultem 1000" (glass transition temperature: 216 ° C.) and "Ultem 1010" (glass transition temperature: 216) manufactured by General Electric Co., Ltd. ° C.), Examples of the polyetherimide having a repeating unit of the structure represented by the above formula (9) include "Ultem CRS5001" (glass transition temperature Tg226 ° C.), and as another specific example, manufactured by Mitsui Chemicals Co., Ltd. The trade name "Aurum PL500AM" (glass transition temperature 258 ° C.) and the like can be mentioned.

The method for producing the polyetherimide is not particularly limited, but usually, the amorphous polyetherimide having the structure represented by the above formula (8) is 4,4'-[isopropyridenebis (p.). -Phenyleneoxy)] As a polycondensate of diphthalic acid dianhydride and m-phenylenediamine, and the polyetherimide having the structure represented by the above structural formula (9) is 4,4'-[isopropyridenebis. (P-Phenyleneoxy)] It is synthesized by a method known as a polycondensate of diphthalic acid dianhydride and p-phenylenediamine.

Further, the polyetherimide may contain other copolymerizable monomer units such as an amide group, an ester group and a sulfonyl group within a range not exceeding the gist of the present invention. The polyetherimide may be used alone or in combination of two or more.

(4) The transparent heat-resistant resin having a polyesterimide imide structure preferably contains the polyesterimide structure represented by the formula (10) in the constituent unit.

（式（１０）中、Ｒ_１は特定の構造を有する２価の基を表す。Ｒ_２は２価の鎖式脂肪族基、２価の環式脂肪族基又は２価の芳香族基を表す。）
式（１０）中、Ｒ_１は、それぞれ、式（１１）、式（１２）又は式（１３）で表される構造を有する２価の基を表す。

(In the formula (10), R ₁ represents a divalent group having a specific structure. R ₂ represents a divalent chain aliphatic group, a divalent cyclic aliphatic group or a divalent aromatic group. Represent.)
In formula (10), R ₁ represents a divalent group having a structure represented by formula (11), formula (12) or formula (13), respectively.

式（１１）中、Ｒは、それぞれ２価の、鎖式脂肪族基、環式脂肪族基又は芳香族基を表し、複数個のＲは、互いに同一であっても、異なっていてもよい。これらの鎖式脂肪族基、環式脂肪族基又は芳香族基を、単独、又は２種類以上を組み合わせて使用することもできる。 (A divalent group having a structure represented by the formula (11))

In the formula (11), R represents a divalent chain aliphatic group, a cyclic aliphatic group or an aromatic group, respectively, and a plurality of Rs may be the same as or different from each other. .. These chain aliphatic groups, cyclic aliphatic groups or aromatic groups may be used alone or in combination of two or more.

m is a positive integer of 1 or more, preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. The upper limit of m is not particularly limited, but is preferably 25 or less, more preferably 20 or less, and further preferably 10 or less. If it exceeds 25, the heat resistance tends to decrease.

The chain aliphatic group, cyclic aliphatic group or aromatic group is "chain aliphatic compound having a divalent hydroxy group", "cyclic aliphatic compound having a divalent hydroxy group" or "2. It is desirable that the residue is derived from a diol such as "an aromatic compound having a valent hydroxy group". Further, it may be a residue derived from a "polycarbonate diol" that can be polymerized from the diol and carbonic acid esters, phosgene, or the like.

As the "chain-type aliphatic compound having a divalent hydroxy group", a branched or linear diol having two hydroxy groups can be used. For example, alkylene diol, polyoxyalkylene diol, polyester diol, polycaprolactone diol and the like can be mentioned. The following are branched or linear diols having two hydroxy groups that can be used as "chain aliphatic compounds having a divalent hydroxy group".

Examples of the alkylene diol include ethylene glycol, diethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and the like. 1,6-Hexanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-cyclohexanediol, 1,4- Cyclohexanedimethanol and the like can be mentioned.

Examples of the polyoxyalkylene diol include dimethylol propionic acid (2,2-bis (hydroxymethyl) propionic acid), dimethylolbutanoic acid (2,2-bis (hydroxymethyl) butanoic acid), polyethylene glycol, polypropylene glycol, and the like. Examples thereof include polytetramethylene glycol, polyoxytetramethylene glycol, and random copolymers of tetramethylene glycol and neopentyl glycol. Preferably, polyoxytetramethylene glycol is preferable.

Examples of the polyester diol include a polyester diol obtained by reacting a polyhydric alcohol exemplified below with a polybasic acid.

As the "multihydric alcohol component" used for the polyester diol, any various polyhydric alcohols can be used. For example, ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5. -Pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, cyclohexanemethanol, Neopentyl hydroxypiparic acid ester, ethylene oxide adduct and propylene oxide adduct of bisphenol A, ethylene oxide adduct and propylene oxide adduct of water-added bisphenol A, 1,9-nonanediol, 2-methyloctanediol, 1 , 10-Dodecanediol, 2-butyl-2-ethyl-1,3-propanediol, tricyclodecanemethanol, polyethylene glycol, polypropylene glycol, polyether polyols such as polytetramethylene glycol and the like can be used.

Any various polybasic acids can be used as the "polybasic acid component" used for the polyester diol. For example, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalic acid, 2,6-naphthalic acid, 4,4'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid. Acid, adipic acid, sebacic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, dimer acid, etc. Fat group and alicyclic dibasic acids can be used.

Specific examples of commercially available polyester diols include ODX-688 (aliphatic polyester diol manufactured by DIC Co., Ltd .: adipic acid / neopentyl glycol / 1,6-hexanediol, number average molecular weight of about 2000), Vylon (registered). Trademark) 220 (polyester diol manufactured by Toyobo Co., Ltd., number average molecular weight of about 2000) and the like can be mentioned.

Examples of the polycaprolactone diol include polycaprolactone diol obtained by ring-opening addition reaction of lactones such as γ-butyllactone, ε-caprolactone and δ-valerolactone.

The above-mentioned "chain-type aliphatic compound having a divalent hydroxy group" can be used alone or in combination of two or more.

Examples of the "cyclic aliphatic compound having a divalent hydroxy group" or the "aromatic compound having a divalent hydroxy group" include "a compound having two hydroxy groups on an aromatic ring or a cyclohexane ring" and "two. "Compounds in which phenol or alicyclic alcohol is bonded with a divalent functional group", "Compounds having one hydroxy group in both nuclei of the biphenyl structure", "Compounds having two hydroxy groups in the naphthalene skeleton", etc. Is used.

As "compounds having two hydroxy groups on the aromatic ring and cyclohexane ring", hydroquinone, 2-methylhydroquinone, resorcinol, catechol, 2-phenylhydroquinone, cyclohexanedimethanol, tricyclodecanemethanol, 1,4-dihydroxycyclohexane, 1 , 3-Dihydroxycyclohexane, 1,2-dihydroxycyclohexane, 1,3-adamantandiol, dicyclopentadiene dihydrate, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxy Carboxy group-containing diols such as benzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, and 3,5-dihydroxybenzoic acid can be used.

Examples of "two phenols" or "compounds in which an alicyclic alcohol is bonded with a divalent functional group" include 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4, 4'-(9-fluorenylidene) diphenol, 4,4'-dihydroxydicyclohexyl ether, 4,4'-dihydroxydicyclohexylsulfone, bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F and the like can be used.

Further, as an example of "a compound having one hydroxy group in both nuclei of the biphenyl structure", 4,4'-biphenol, 3,4'-biphenol, 2,2'-biphenol, 3,3', 5 , 5'-Tetramethyl-4,4'-biphenol and the like can be used.

Examples of the "compound having two hydroxy groups in the naphthalene skeleton" include 2,6-naphthalenediol, 1,4-naphthalenediol, 1,5-naphthalenediol, 1,8-naphthalenediol and the like.

The number average molecular weight of the diol is preferably 100 or more and 30,000 or less, more preferably 150 or more and 20,000 or less, and further preferably 200 or more and 10,000 or less. If the number average molecular weight is less than 100, low hygroscopicity and flexibility cannot be sufficiently exhibited.

If it is larger than 30,000, phase separation may not be possible and mechanical properties and colorless transparency may not be sufficiently exhibited depending on the composition and structure of the "diol" and the composition and structure of the diamine component (or isocyanate component) described later. ..

The polycarbonate diol may be a polycarbonate diol (copolymerized polycarbonate diol) having a plurality of types of alkylene groups described above in its skeleton. For example, a combination of 2-methyl-1,8-octanediol and 1,9-nonanediol, a combination of 3-methyl-1,5-pentanediol and 1,6-hexanediol, a combination of 1,5-pentanediol and 1 , Copolymerized polycarbonate diol that can be synthesized by a combination of 6-hexanediol and the like can be mentioned. Preferably, it is a copolymerized polycarbonate diol that can be synthesized from a combination of 2-methyl-1,8-octanediol and 1,9-nonanediol. Two or more of these polycarbonate diols can be used in combination.

Examples of commercially available polycarbonate diols that can be used include Kuraray polyol C series manufactured by Kuraray Co., Ltd. and Duranol series manufactured by Asahi Kasei Chemicals Co., Ltd. For example, Clare polyol C-1015N, Clare polyol C-1065N (carbonate diol manufactured by Kurare Co., Ltd .: 2-methyl-1,8-octanediol / 1,9-nonanediol, number average molecular weight of about 1000), Clare polyol C -2015N, Clare polyol C2065N (carbonate diol manufactured by Clare Co., Ltd .: 2-methyl-1,8-octanediol / 1,9-nonanediol, number average molecular weight of about 2000), Clare polyol C-1050, Clare polyol C- 1090 (Carlate carbonate diol manufactured by Clare Co., Ltd .: 3-methyl-1,5-pentanediol / 1,6-hexanediol, number average molecular weight of about 1000), Clare polyol C-2050, Clare polyol C-2090 (Co., Ltd.) Kulare carbonate diol: 3-methyl-1,5-pentanediol / 1,6-hexanediol, number average molecular weight of about 2000), duranol T5650E (Polycarbonate diol manufactured by Asahi Kasei Chemicals Co., Ltd .: 1,5-pentanediol / 1) , 6-Hexanediol, number average molecular weight about 500), Duranol T5651 (Polycarbonadiol manufactured by Asahi Kasei Chemicals Co., Ltd .: 1,5-pentanediol / 1,6-hexanediol, number average molecular weight about 1000), Duranol T5652 (Asahi Kasei) Polycarbonatediol manufactured by Chemicals Co., Ltd .: 1,5-pentanediol / 1,6-hexanediol, number average molecular weight of about 2000) and the like can be mentioned. Preferably, Kuraray polyol C-1015N and the like can be mentioned.

Examples of the method for producing the polycarbonate diol include transesterification of the raw material diol with carbonic acid esters and a dehydrochlorination reaction between the raw material diol and phosgene. Examples of the carbonic acid ester as a raw material include dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; diaryl carbonates such as diphenyl carbonate; and alkylene carbonates such as ethylene carbonate and propylene carbonate.

(A divalent group having a structure represented by the formula (12))
A divalent group having a structure represented by the formula (12) will be described.

式（１２）中、Ｒ_３は、直結、アルキレン基（−Ｃ_ｎＨ_２ｎ−）、パーフルオロアルキレン基（−Ｃ_ｎＦ_２ｎ−）、エーテル結合（−Ｏ−）、エステル結合（−ＣＯＯ−）、カルボニル基（−ＣＯ−）、スルホニル基（−Ｓ（＝Ｏ）_２−）、スルフィニル基（−ＳＯ−）、スルフェニル基（−Ｓ−）、カーボネート基（−ＯＣＯＯ−）、又はフルオレニリデン基を表す。ｎは１以上の正の整数である。ｎの上限は特に限定されないが、好ましくは１０以下、より好ましくは５以下、更に好ましくは３以下である。Ｘ_１〜Ｘ_８は、それぞれが同じであっても、異なっていても良く、それぞれ水素、ハロゲン又はアルキル基を表す。

In formula (12), R ₃ is directly linked, alkylene group (-C _n H _2n- ), perfluoroalkylene group (-C _n F _2n- ), ether bond (-O-), ester bond (-COO-). ), Carbonyl group (-CO-), sulfonyl group (-S (= O) _2- ), sulfinyl group (-SO-), sulfenyl group (-S-), carbonate group (-OCOO-), or fluorenylidene. Represents a group. n is a positive integer greater than or equal to 1. The upper limit of n is not particularly limited, but is preferably 10 or less, more preferably 5 or less, and further preferably 3 or less. X _{1 to} X ₈ may be the same or different, and represent hydrogen, halogen, or alkyl groups, respectively.

Specific examples of the divalent group having the structure represented by the formula (12) are not particularly limited, but a diphenyl ether skeleton, a diphenyl sulfone skeleton, a 9-fluorenylidene diphenol skeleton, a bisphenol A skeleton, a bisphenol F skeleton, Examples thereof include an ethylene oxide adduct skeleton of bisphenol A, a propylene oxide adduct skeleton of bisphenol A, a biphenyl skeleton, and a naphthalene skeleton.

The skeleton is preferably a residue derived from a compound having one hydroxy group each on both benzene rings of the formula (12). Examples of the raw material of the divalent group having the structure represented by the formula (12) include 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4,4'-(9-fluorenylidene) diphenol, and the like. Bisphenol A, bisphenol F, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, 4,4'-biphenol, 3,4'-biphenol, 2,2'-biphenol, 3,3', 5, 5'-tetramethyl-4,4'-biphenol, 2,6-naphthalene diol, 1,4-naphthalene diol, 1,5-naphthalene diol, 1,8-naphthalene diol and the like can be used.

Preferably, an ethylene oxide adduct of 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4,4'-(9-fluorenylidene) diphenol or bisphenol A is preferable. More preferably, it is an ethylene oxide adduct of 4,4'-dihydroxydiphenyl ether or bisphenol A.

These compounds can be used alone or in combination of two or more. By using these materials, it is possible for R ₁ position of formula (10), introducing the diphenyl ether skeleton, or the like.

式（１３）中、Ｒ_４は、直結、アルキレン基（−Ｃ_ｎＨ_２ｎ−）、パーフルオロアルキレン基（−Ｃ_ｎＦ_２ｎ−）、エーテル結合（−Ｏ−）、エステル結合（−ＣＯＯ−）、カルボニル基（−ＣＯ−）、スルホニル基（−Ｓ（＝Ｏ）_２−）、スルフィニル基（−ＳＯ−）、スルフェニル基（−Ｓ−）、カーボネート基（−ＯＣＯＯ−）、又はフルオレニリデン基を表す。ｎは１以上の正の整数である。ｎの上限は特に限定されないが、好ましくは１０以下、より好ましくは５以下、更に好ましくは３以下である。Ｘ_１′〜Ｘ_８′は、それぞれが同じであっても、異なっていても良く、それぞれ水素、ハロゲン又はアルキル基を表す。 (A divalent group having a structure represented by the formula (13))

In formula (13), R ₄ is directly linked, alkylene group (-C _n H _2n- ), perfluoroalkylene group (-C _n F _2n- ), ether bond (-O-), ester bond (-COO-). ), Carbonyl group (-CO-), sulfonyl group (-S (= O) _2- ), sulfinyl group (-SO-), sulfenyl group (-S-), carbonate group (-OCOO-), or fluorenylidene. Represents a group. n is a positive integer greater than or equal to 1. The upper limit of n is not particularly limited, but is preferably 10 or less, more preferably 5 or less, and further preferably 3 or less. X 1 _{'~X 8'} can be respectively the same or different, each represents hydrogen, a halogen or an alkyl group.

Specific examples of the divalent group having the structure represented by the formula (13) are not particularly limited, but are a dicyclohexyl ether skeleton, a dicyclohexylsulfone skeleton, a hydrogenated bisphenol A skeleton, a hydrogenated bisphenol F skeleton, and a hydrogenated bisphenol A skeleton. Examples include the ethylene oxide adduct skeleton of hydrogenated bisphenol A and the propylene oxide adduct skeleton of hydrogenated bisphenol A.

The skeleton is preferably a residue derived from a compound having one hydroxy group each on both cyclohexane rings of formula (13). Examples of the raw material of the divalent group having the structure represented by the formula (13) include 4,4'-dihydroxydicyclohexyl ether, 4,4'-dihydroxydicyclohexylsulfone, hydrogenated bisphenol A, hydrogenated bisphenol F, and hydrogenated. An ethylene oxide adduct of bisphenol A or a propylene oxide adduct of hydrogenated bisphenol A can be used.

Preferably, 4,4'-dihydroxydicyclohexyl ether or 4,4'-dihydroxydicyclohexylsulfone is preferable.

These compounds can be used alone or in combination of two or more. By using these materials, it is possible for R ₁ position of formula (10), introducing said dicyclohexyl ether skeleton or the like.

For example, the structure of the formula (10) is obtained by reacting a halide of a cyclohexanetricarboxylic acid anhydride with diols to obtain an ester group-containing tetracarboxylic acid dianhydride, and then the ester group-containing tetracarboxylic acid. It can be obtained by subjecting a dianoxide to a condensation reaction (polymethylation) with a diamine, diisocyanate, or the like.

(A divalent group having a structure represented by the formula (14))
The polyesterimide resin may further contain a structure represented by the formula (14) in the structural unit.

式（１０）のＲ_２及び式（１４）のＲ_２′について説明する。Ｒ_２及びＲ_２′はそれぞれ独立して、２価の鎖式脂肪族基、２価の環式脂肪族基又は２価の芳香族基であれば特に限定されない。これらの「２価の鎖式脂肪族基」、「２価の環式脂肪族基」、「２価の芳香族基」を、単独、又は２種類以上を組み合わせて使用することもできる。

Described _{R 2} 'of _{R 2} of the formula (10) (14). R ₂ and R ₂ ′ are not particularly limited as long as they are independently divalent chain aliphatic groups, divalent cyclic aliphatic groups or divalent aromatic groups. These "divalent chain aliphatic groups", "divalent cyclic aliphatic groups", and "divalent aromatic groups" can be used alone or in combination of two or more.

Preferably, R ₂ is a divalent group having a structure represented by the following formula (15), and R ₂ ′ is a divalent group having a structure represented by the following formula (16).

(A divalent group having a structure represented by the formula (15))
R ₂ in the formula (10) is preferably a divalent group having a structure represented by the formula (15) in view of the balance between heat resistance, flexibility, and low hygroscopicity.

式（１５）中、Ｒ_５は、直結、アルキレン基（−Ｃ_ｎＨ_２ｎ−）、パーフルオロアルキレン基（−Ｃ_ｎＦ_２ｎ−）、エーテル結合（−Ｏ−）、エステル結合（−ＣＯＯ−）、カルボニル基（−ＣＯ−）、スルホニル基（−Ｓ（＝Ｏ）_２−）、スルフィニル基（−ＳＯ−）又はスルフェニル基（−Ｓ−）を表す。ｎは１以上１０以下の正の整数であることが好ましく、より好ましくは１以上５以下、さらに好ましくは１以上３以下である。Ｘ_９〜Ｘ_１６は、同じであっても、異なっていても良く、それぞれ水素、ハロゲン又はアルキル基を表す。

In formula (15), R ₅ is directly linked, alkylene group (-C _n H _2n- ), perfluoroalkylene group (-C _n F _2n- ), ether bond (-O-), ester bond (-COO-). ), A carbonyl group (-CO-), a sulfonyl group (-S (= O) _2- ), a sulfinyl group (-SO-) or a sulfenyl group (-S-). n is preferably a positive integer of 1 or more and 10 or less, more preferably 1 or more and 5 or less, and further preferably 1 or more and 3 or less. X _{9 to} X ₁₆ may be the same or different and represent hydrogen, halogen or alkyl groups, respectively.

(A divalent group having a structure represented by the formula (16))
The R ₂ ′ in the formula (14) is preferably a divalent group having a structure represented by the formula (16) in view of the balance between heat resistance, flexibility, low hygroscopicity and the like.

式（１６）中、Ｒ_５′は、直結、アルキレン基（−Ｃ_ｎＨ_２ｎ−）、パーフルオロアルキレン基（−Ｃ_ｎＦ_２ｎ−）、エーテル結合（−Ｏ−）、エステル結合（−ＣＯＯ−）、カルボニル基（−ＣＯ−）、スルホニル基（−Ｓ（＝Ｏ）_２−）、スルフィニル基（−ＳＯ−）又はスルフェニル基（−Ｓ−）を表す。ｎは１以上１０以下の正の整数であることが好ましく、より好ましくは１以上５以下、さらに好ましくは１以上３以下である。Ｘ_９′〜Ｘ_１６′は、同じであっても、異なっていても良く、それぞれ水素、ハロゲン又はアルキル基を表す。

Wherein (16), _{R 5} 'are directly connected, an alkylene group _{(-C n H 2n} -), perfluoroalkylene group _{(-C n F 2n} -), ether bond (-O-), an ester bond (-COO Represents a −), a carbonyl group (−CO−), a sulfonyl group (−S (= O) ₂₋ ), a sulfinyl group (−SO−) or a sulfenyl group (−S−). n is preferably a positive integer of 1 or more and 10 or less, more preferably 1 or more and 5 or less, and further preferably 1 or more and 3 or less. X ₉ ′ to X ₁₆ ′ may be the same or different and represent hydrogen, halogen or alkyl groups, respectively.

In the formula (10) and (14), "a divalent chain aliphatic group", "divalent cyclic aliphatic group" or "divalent aromatic group" of R ₂ position of formula (10) and to introduce the R _{2 'position} of formula (14), it is preferable to use the corresponding diamine or diisocyanate component. That is, "aromatic diamine or corresponding aromatic diamine", "cyclic aliphatic diamine or corresponding cyclic aliphatic diamine", "chain aliphatic diamine or corresponding chain aliphatic diamine" are appropriately used. By selecting it, a polyesterimide resin having excellent heat resistance, flexibility, and low moisture absorption can be obtained.

The diamine component of R _{2 of the} formula (10) and R ₂ ′ of the formula (14) or the corresponding diisocyanate component may be the same or different. It is preferably the same, based on the preferred manufacturing method described below.

The diamine component having R ₂ and R ₂ ′ as the basic skeleton or the corresponding diisocyanate component will be described.

Specific examples of the "aromatic diamine or the corresponding aromatic diisocyanate" include 2,2'-bis (trifluoromethyl) benzidine, p-phenylenediamine, m-phenylenediamine, 2 as a diamine compound. , 4-Diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, 2,4-diaminodurene, 4,4'-diaminodiphenylmethane, 4,4'-methylenebis (2-methylaniline), 4, 4'-methylenebis (2-ethylaniline), 4,4'-methylenebis (2,6-dimethylaniline), 4,4'-methylenebis (2,6-diethylaniline), 4,4'-diaminodiphenyl ether, 3 , 4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminobenzophenone, 3 , 3'-diaminobenzophenone, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfide, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminobenz Anilide, P-xylene diamine, m-xylene diamine, 1,4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, benzidine, 3,3'-dihydroxybenzidine, 3,3'-Dimethoxybenzidine, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'- Diaminobiphenyl, 2,2'-diethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-diethoxy-4,4'-diaminobiphenyl, o- Trizine, m-trizine, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4'- Bis (4-aminophenoxy) biphenyl, bis (4- (3-aminophenoxy) phenyl) sulfone, bis (4- (4-aminophenoxy) phenyl) sulfone, 2,2-bis (4- (4-aminophenoxy) phenyl) ) Phenyl) propane, 2,2-bis (4- (4-aminophenoxy) fe Nyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, diaminoterphenyl and the like can be mentioned. Further, these may be used in combination of two or more.

Further, examples of the "cyclic aliphatic diamine or the corresponding cyclic aliphatic diisocyanate" as a diamine compound include trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, and 1,4-diamino. Cyclohexane (trans / cis mixture), 1,3-diaminocyclohexane, 4,4'-methylenebis (cyclohexylamine) (trans, cis, trans / cis mixture), isophoronediamine, 1,4-cyclohexanebis (methylamine) ), 2,5-bis (aminomethyl) bicyclo [2.2.1] heptane, 2,6-bis (aminomethyl) bicyclo [2.2.1] heptane, 3,8-bis (aminomethyl) tricyclo [5.2.1.0] Decane, 1,3-diaminoadamantan, 4,4'-methylenebis (2-methylcyclohexylamine), 4,4'-methylenebis (2-ethylcyclohexylamine), 4,4' -Methylenebis (2,6-dimethylcyclohexylamine), 4,4'-Methylenebis (2,6-diethylcyclohexylamine), 2,2-bis (4-aminocyclohexylamine) propane, 2,2-bis (4-amino) Cyclohexylamine) Hexafluoropropane and the like can be mentioned. Further, these may be used in combination of two or more.

Examples of the "chain-type aliphatic diamine or the corresponding chain-type aliphatic diamine" include 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1, Examples thereof include 6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, and 1,9-nonamethylenediamine. Further, these may be used in combination of two or more.

From the viewpoint of the balance of heat resistance, flexibility, low moisture absorption, etc., the diamine component of R ₂ in the formula (10) and the diamine component of R ₂ ′ in the formula (14) or the corresponding diamine component is exemplified as a diamine compound. Then, p-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 1,5-naphthalenediamine, o-trizine, diaminoterphenyl, 4,4'- It is a residue derived from methylenebis (cyclohexylamine), isophorone diamine, etc. More preferred are 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 1,5-naphthalenediamine, o-trizine, and even more preferred are 4,4'-diaminodiphenylmethane, 4,4'. -Diaminodiphenyl ether, o-trizine. Most preferably, it is a residue derived from 4,4'-diaminodiphenylmethane, o-tridine.

It is preferable that the polyimide according to the present invention contains a polyimide fluoride from the viewpoint of excellent transparency of the polyimide film and easy heat correction by heat shrinkage. The fluorine content is more preferably contained in the film in the range of 1 to 40% by mass because the effect of the present invention is large.
<Solubility of polyimide in dichloromethane or 1,3-dioxolane>
The polyimide according to the present invention has a limit amount (solubility) of 1 to 50 g that can be dissolved in 100 g of dichloromethane or 100 g of 1,3-dioxolane at 25 ° C. If the solubility is 1 g or more, it can be easily produced by the solution casting method. If the solubility is 50 g or more, it becomes difficult to form a film when the solution is poured, and it becomes difficult to form a film.

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 polyimide soluble, it is effective to reduce the proportion of imide groups and aromatic hydrocarbon structures that act in the direction of increasing the flatness of the molecular skeleton of polyimide. It is also effective to introduce structural isomers and bending groups, introduce aliphatic groups and alicyclic groups instead of aromatic groups, and introduce bulky skeletons such as fluorine atoms and fluorene.

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 dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, (bicyclo [4.2.0] octane) -3,4,5,8-tetracarboxylic dianhydride) Bicyclo [2.2.1] heptanedimethaneamine, as a structure with a bending group, 2,3', 3,4'-biphenyltetracarboxylic Acid dianhydride, 3,4'-oxydiphthalic dianhydride, 4,4'oxydiphthalic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4 ′-Diphenylsulfonetetracarboxylic dianhydride, 2,2-bis (4- (3,4-dicarboxyphenoxy) phenyl) propanedianhydride, 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) Examples thereof include −aminophenoxy) benzene, bis (3-aminophenyl) sulfone, 3,3′-diaminobenzophenone, and 3,4′-diaminodiphenyl ether.

Examples of the compound containing a fluorine atom include 4,4'-(hexafluoroisopropyridene) diphthalic acid anhydride, 2,2'-bis (trifluoromethyl) benzidine, and 2,2-bis (3-amino-). As a compound containing 4-hydroxyphenyl) hexafluoropropane and a fluorene group, 9,9-bis (4-amino-3-fluorophenyl) fluorene and 9,9-bis [4- (3,4-dicarboxy) Phenoxy) -phenyl] fluorene anhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -phenyl] fluorene anhydride, 9,9-Bis (3,4-dicarboxyphenyl) fluorofluorene Dianhydride Can be mentioned.

A polyimide having a limit amount (solubility) of 1 g or more that dissolves in 100 g of dichloromethane at 25 ° C. tends to be a transparent film having a total light transmittance of 80% or more. Further, it tends to be a colorless film having a yellow index value (YI value) of 4.0 or less.

<Physical properties of polyimide film>
(Surface elastic modulus)
The polyimide film of the present invention is characterized in that the difference between the surface elastic modulus of one surface (A) of the polyimide film and the surface elastic modulus of the other surface (B) is 2 GPa or less.

By setting the difference in surface elastic modulus to 2 GPa or less, the durability against keystrokes when the polyimide film is used as the base material of the transparent conductive film is good, and there is little variation in durability.

The difference in surface elastic modulus is more preferably 1 GPa or less, and most preferably 0 GPa.

The surface elastic modulus of the polyimide film can be measured by using a micro surface hardness tester. The specific method is as follows. A Vickers indenter (tip ridge angle 90 °, tip radius of curvature 35 to 50 nm) was brought into contact with the sample surface using a micro surface hardness tester (Triboscope manufactured by Hysiron), and then the load was increased to 1 mN in 10 seconds. Hold for 5 seconds. The penetration depth of the Vickers indenter at this time is Dv0. After that, when the load is 0 mN, the force (Fv) and the penetration depth (Dv) for pushing back the Vickers indenter are measured, and the inclination thereof is taken as the surface elastic modulus. This measurement is performed at 25 ° C. and 60% RH, and is represented by an average value of 10 points. Details of the principle are described in Handbook of Micro / Nano Tribology (Bharat Bhushan ed. CRC).

The difference between the surface elastic modulus of one surface (A) of the polyimide film and the surface elastic modulus of the other surface (B) in the present invention is determined from the numerical value of the surface elastic modulus of the surface having a large surface elastic modulus. It is a value obtained by subtracting the numerical value of the surface elastic modulus of the surface having a small elastic modulus, and is a positive value.

(Total light transmittance)
The polyimide film according to the present invention is preferably a transparent polyimide film, and as a measure of transparency, it is preferable that the total light transmittance is 80% or more when a sample having a thickness of 55 μm is prepared. It is more preferably 85% or more, and further preferably 90% or more. The higher the total light transmittance, the higher the transparency, which is preferable. The description of the numerical value that the total light transmittance is 80% or more indicates the preferable range.

The total light transmittance of the polyimide film can be measured according to JIS K 7375-2008 with one polyimide film sample whose humidity has been adjusted for 24 hours in an air conditioning room at 23 ° C. and 55% RH. For the measurement, the transmittance in the visible light region (range of 400 to 700 nm) can be measured using a spectrophotometer U-3300 of Hitachi High-Technologies Corporation.

In order to make the total light transmittance 80% or more, it can be adjusted by selecting the type of the above-mentioned polyimide.

(Yellow index value (YI value))
The polyimide film according to the present invention is preferably a colorless polyimide film. As a guideline for being colorless, the yellow index value (YI value) is preferably 4.0 or less. It is more preferably in the range of 0.3 to 2.0, and particularly preferably in the range of 0.3 to 1.6. The smaller the yellow index value (YI value), the less the coloring, which is preferable. The description of the numerical value that the yellow index value (YI value) is 4.0 or less indicates the preferable range.

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

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

As a method for measuring the yellow index value, a film sample is prepared, and a light source specified in JIS Z 8701 is used using a spectrophotometer U-3300 of Hitachi High-Technologies Corporation and an attached saturation calculation program. 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 equation.

Yellow index (YI) = 100 (1.28X-1.06Z) / Y
(Haze value)
In the present invention, it is preferable that the haze value of the roll-type polyimide film after heat treatment is 4% or less from the viewpoint of high transparency of the polyimide film.

The haze can be measured by the haze meter NDH 2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K 7136. 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 luminosity filter).

<Other additives>
(UV absorber)
It is preferable that the polyimide film of the present invention contains an ultraviolet absorber from the viewpoint of improving light resistance. The ultraviolet absorber aims to improve the light resistance by absorbing ultraviolet rays of 400 nm or less, and in particular, the transmittance at a wavelength of 370 nm is preferably in the range of 0.1 to 30%, which is more preferable. Is in the range of 1 to 20%, more preferably in the range of 2 to 10%.

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

For example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazole-2-yl) -6- (straight and side). Chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, etc., and also chinubin 109, chinubin 171, chinubin 234, chinubin 326, chinubin 327, chinubin 328, There are chinubins such as chinubin 928, all of which are commercially available products manufactured by BASF Japan Co., Ltd. and can be preferably used. Of these, halogen-free ones are preferable.

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

The polyimide film of the present invention preferably contains two or more types of ultraviolet absorbers.

Further, as the ultraviolet absorber, a polymer ultraviolet absorber can also be preferably used, and in particular, the 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 ultraviolet absorber is to dissolve the ultraviolet absorber in an alcohol such as methanol, ethanol or butanol, an organic solvent such as dichloromethane, methyl acetate, acetone or dioxolane, or a mixed solvent thereof, and then add the ultraviolet absorber to the dope. It may be added directly into the dope composition.

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

(Antioxidant)
Antioxidants are also called antioxidants. When an electronic device or the like is placed in a high humidity and high temperature state, the polyimide film may be deteriorated.

The antioxidant has a role of delaying or preventing the decomposition of the polyimide film due to, for example, halogen in the residual solvent amount in the polyimide film, phosphoric acid of the phosphoric acid-based plasticizer, or the like, and thus the polyimide film of the present invention. It is preferable to contain it in.

As such an antioxidant, the compounds described in paragraphs 0108 to 0119 of JP-A-2010-271619 can be preferably used.

The amount of these compounds added is preferably in the range of 1 ppm to 1.0% in terms of mass ratio with respect to the polyimide film, and more preferably in the range of 10 to 1000 ppm.

(Peeling accelerator)
A peeling accelerator may be added to the polyimide film of the present invention in order to improve the peelability during film production.

Many of the additives that reduce the peeling resistance of the polyimide film have a remarkable effect on surfactants, and preferable peeling agents are phosphoric acid ester-based surfactants, carboxylic acid or carboxylate-based surfactants, and the like. Sulfonic acid or sulfonate-based surfactants and sulfate ester-based surfactants are effective. Further, a fluorine-based surfactant in which a part of hydrogen atoms bonded to the hydrocarbon chain of the above-mentioned surfactant is replaced with a fluorine atom is also effective. The release agent is illustrated below.
RZ-1 C ₈ H ₁₇ OP (= O)-(OH) ₂
RZ-2 C ₁₂ H ₂₅ OP (= O)-(OK) ₂
RZ-3 C ₁₂ H ₂₅ OCH ₂ CH ₂ OP (= O)-(OK) ₂
RZ-4 C ₁₅ H ₃₁ (OCH ₂ CH ₂ ) ₅ OP (= 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 (t-C 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 triisopropylnaphthalene sulphonate RZ-16 Sodium tri-t-butylnaphthalene sulphonate 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 amount of the peeling accelerator added 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 polyimide.

If necessary, other additives such as inorganic fine particles and a retardation adjuster can be used in the polyimide film of the present invention.

<Manufacturing method of polyimide film>
A specific example of the method for producing the polyimide film will be described below.

The method for producing a polyimide film of the present invention includes a step of preparing a dope containing polyimide and a solvent, a step of casting the dope onto a support to form a film, and a step of peeling the film from the support. The step of drying the peeled film is included.

The method for producing a polyimide film of the present invention includes a step of preparing a dope containing the polyimide and a solvent (dope preparation step) and a step of casting the dope on a support to form a film (casting step). ), A step of peeling the film from the support (peeling step), a step of drying the obtained cast film to obtain a film (first drying step), a step of stretching the dried film (stretching step), A step of further drying the stretched film (second drying step), a step of winding the obtained polyimide film (winding step), and a step of heat-treating the film to imidize it if necessary (heating step). Etc. are more preferable.

Hereinafter, each step will be specifically described.

(Dope preparation process)
In the method for producing a polyimide film of the present invention, it is preferable that a soluble polyimide is dissolved in a solvent to prepare a dope, 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 point solvent having a boiling point of 80 ° C. or lower as the main solvent because the film manufacturing process temperature (particularly the drying temperature) can be reduced and the heat shrinkage rate can be reduced. Here, "used as the main solvent" means that 55% by mass or more is used with respect to the total amount of the solvent in the case of a mixed solvent, preferably 70% by mass or more, more preferably 80% by mass or more, and particularly preferably. Is to be used in an amount of 90% by mass or more. Of course, if used alone, it will be 100% by mass.

The low boiling point solvent may be any one that dissolves polyimide and other additives at the same time. For example, the chlorine-based solvent is dichloromethane, and the non-chlorine-based solvent is methyl acetate, ethyl acetate, amyl acetate, acetone, etc. 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, Examples thereof include 2,3,3,3-pentafluoro-1-propanol, nitroethane, methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol and the like.

Among the above solvents, low boiling point solvents having a boiling point of 80 ° C. or lower include dichloromethane (40 ° C.), ethyl acetate (77 ° C.), methyl ethyl ketone (79 ° C.), tetrahydrofuran (66 ° C.), and acetone (56.5 ° C.). , And at least one selected from 1,3-dioxolane (75 ° C.) is preferably contained as the main solvent (the boiling points are shown in parentheses).

Further, as the solvent contained in the case of the mixed solvent, as long as it can dissolve the polyimide according to the present invention, it can be used as long as it does not impair the effect of the present invention, and as a solvent other than the above-mentioned ones, For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylcaprolactam, hexamethylphosphoramide, tetramethylene. Solvents, dimethylsulfoxide, m-cresol, phenol, p-chlorophenol, 2-chloro-4-hydroxytoluene, diglyme, triglime, tetraglyme, dioxane, γ-butyrolactone, dioxolane, cyclopentanone, epsilon caprolactam, chloroform, etc. It can be used, and two or more types may be used in combination. In addition to these solvents, poor solvents such as hexane, heptane, benzene, toluene, xylene, chlorobenzene, and o-dichlorobenzene are used to the extent that the polyimide and organic compounds having a carbonyl group according to the present invention do not precipitate. You may.

Further, an alcohol solvent can also be used. It is preferable that the alcohol solvent is selected from methanol, ethanol and butanol from the viewpoint of improving the peelability and enabling high-speed casting. Of these, it is preferable to use methanol or ethanol. Higher proportions of alcohol in the dope gel the web, facilitating delamination from the metal support.

The dissolution of polyimide and other additives is carried out at normal pressure, below the boiling point of the main solvent, and pressurized above the boiling point of the main solvent, JP-A-9-955544, JP-A-9- Various melting methods can be used, such as the method performed by the cooling dissolution method described in JP-A-95557 or JP-A-9-95538, the method performed by the high-pressure method described in JP-A-11-21379, and the like.

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 doping is dichloromethane, the gel-like foreign matter in the doping can be removed by filtering the doping at a temperature of + 5 ° C. or higher at a boiling point of the dichloromethane at 1 atm. The preferred temperature range is 45 to 120 ° C, more preferably 45 to 70 ° C, and even more preferably within the range of 45 to 55 ° C.

Further, as the raw material of the resin used for the doping preparation, those in which polyimide and other compounds are pelletized in advance can also be preferably used.

(Cushion film forming process)
The prepared dope is pumped onto a die through a liquid feed pump (eg, a pressurized metering gear pump) and transferred indefinitely on a metal support such as a stainless belt or a rotating metal drum. Spread the dope from the die to the position.

The metal support in casting 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 width of the cast 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 does not have to 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 such as polytetrafluoroethylene can be used. When polyimide is used as the flexible substrate, the polyimide may be wound together with the metal support in which the polyimide is cast.

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, and particularly preferably 80 to 150 m / min. The higher the traveling speed of the metal support, the easier it is for companion gas to be generated, and the more remarkable the occurrence of film thickness unevenness due to disturbance.

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 gradually becomes thinner toward the discharge port in a cross section perpendicular to the width direction. Specifically, the die usually has tapered surfaces on the downstream side and the upstream side in the lower traveling direction, and the discharge port is formed in a slit shape between the tapered surfaces. A metal die is preferably used, and specific examples thereof include stainless steel and titanium. In the present invention, when producing 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 portion and can easily make the film thickness uniform. The pressure die includes a coat hanger die, a T die, and the like, and any of them is preferably used. Even when films of different thicknesses are continuously manufactured, the discharge rate of the die is maintained at a substantially constant value. Therefore, when a pressure die is used, conditions such as extrusion pressure and shear rate are also omitted. It is maintained at a constant value. Further, in order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the doping amount may be divided and laminated.

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

To evaporate the solvent, for example, a method of blowing heating air from the casting film side and the back side of the metal support with a dryer, a method of transferring heat from the back surface of the metal support with a heating liquid, and a method of transferring heat from the front and back by radiant heat. And so on. 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 differ 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 even more preferably 120 ° C. or lower.

In the solvent evaporation step, it is preferable to dry the casting film until the residual solvent amount is within the range of 10 to 150% by mass from the viewpoint of the peelability of the casting 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 (mass%) = {(MN) / N} x 100
Here, M is the mass of the casting film (film) at a predetermined time point, and N is the mass of M when it is dried at 200 ° C. for 3 hours. In particular, M when calculating the residual solvent amount achieved in the solvent evaporation step is the mass of the cast film immediately before the peeling step.

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

The peeling tension when peeling the metal support and the casting film is usually in the range of 60 to 400 N / m, but if wrinkles are likely to occur during peeling, the metal support is peeled at a tension of 190 N / m or less. 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 the most preferable.

In the method for producing a polyimide film of the present invention, in the step of peeling the cast film from the support, the residual solvent amount of the organic solvent having a boiling point of 80 ° C. or lower is 5 to 40% by mass, or 100 to 200% by mass. It is characterized by being peeled off in a state.

The difference in elastic modulus between the A-side and the B-side is reduced to 2 GPa or less by peeling while the residual solvent amount at the time of casting is in the range of 5 to 40% by mass or 100 to 200% by mass. can do.

As a means of achieving a state in which the residual solvent amount of the casting film is in the range of 5 to 40% by mass or in the range of 100 to 200% by mass, the support temperature at the time of casting is changed, or the atmospheric temperature is changed. It can be adjusted by changing the drying time, dew point, drying air volume, and wind speed on the support.

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

(1st drying step)
The first drying step is a drying step of heating the film and further evaporating the solvent. The drying means is not particularly limited, and for example, hot air, infrared rays, a heating roller, microwaves, or the like can be used. From the viewpoint of simplicity, it is preferable to dry the film with hot air or the like while transporting the film with rollers arranged in a staggered pattern. The drying temperature is preferably in the range of 30 to 200 ° C. in consideration of the amount of residual solvent, the expansion / contraction rate during transportation, and the like.

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

By lowering 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, etc. of the film can be controlled.

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

The stretching operation may be carried out in multiple stages. Further, when biaxial stretching is performed, simultaneous biaxial stretching may be performed, or biaxial stretching may be performed step by step. In this case, the term “stepwise” means, for example, that 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 of the steps. Is also possible.

That is, for example, the following stretching steps are also possible:
・ Stretching in the longitudinal direction → Stretching in the width direction → Stretching in the longitudinal direction → Stretching in the longitudinal direction ・ Stretching in the width direction → Stretching in the width direction → Stretching in the longitudinal direction → Stretching in the longitudinal direction Also, for simultaneous biaxial stretching Also includes the case of stretching in one direction and contracting the other with relaxation of tension. The preferable stretching ratio of simultaneous biaxial stretching can be in the range of × 1.01 times to × 1.5 times 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 can be obtained, and if it is 200% or less, stretching is easy.

In the method for producing a polyimide 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 within a desired range. It is preferable to stretch the polyimide film in a temperature range of (Tg-200) to (Tg + 100) ° C. with respect to the glass transition temperature (Tg). Stretching in the above temperature range lowers the haze because the stretching stress can be reduced. In addition, a polyimide film that suppresses the occurrence of breakage and is excellent in flatness and colorability of the polyimide film itself can be obtained. The stretching temperature is more preferably in the range of (TgL-150) to (TgH + 50) ° C.

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

In order to stretch in the width direction, for example, the width of both ends of the film is held by a clip or a pin in the width direction by performing a total drying treatment or a part of the treatment as shown in JP-A-62-46625. A method of drying while drying (called a tenter method), in particular, a tenter method using a clip is preferably used.

It is preferable that the film stretched in the longitudinal direction or the unstretched film is introduced into the tenter with both ends in the width direction gripped by the clip, and is stretched in the width direction while traveling together with the tenter clip.

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

If the stretching speed is 50% / min or more, the flatness is improved and the film can be processed at high speed, which is preferable from the viewpoint of production suitability. If the stretching speed is 1000% / min or less, the film breaks. It can be processed without any problem, which is preferable.

A more preferable stretching rate is in the range of 100 to 500% / min. The stretching rate is defined by the following formula.

Stretching rate (% / min) = [(d ₁ / d ₂ ) -1] × 100 (%) / t
(In the above formula, d ₁ is the width dimension of the resin film after stretching in the stretching direction, d ₂ is the width dimension of the resin film before stretching in the stretching direction, and t is the time (min) required for stretching. .)
In the stretching step, holding / relaxation is usually performed after stretching. That is, in this step, it is preferable to perform a stretching step of stretching the film, a holding step of holding the film in a stretched state, and a relaxing step of relaxing the film in the stretching direction in these orders. In the holding step, the stretching at the stretching ratio achieved in the stretching step is held at the stretching temperature in the stretching step. In the relaxation step, the stretching in the stretching step is held in the holding step, and then the tension for stretching is released to relax the stretching. The relaxation step may be performed at a temperature equal to or lower than the stretching temperature in the stretching step.

(Second drying step)
Then, the stretched film is heated and dried. When the film is heated by 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 a 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 and the like can be used. From the viewpoint of simplicity, it is preferable to dry the film with hot air or the like while transporting the film with rollers arranged in a staggered pattern. The drying temperature is preferably in the range of 40 to 150 ° C. from the viewpoint that heat shrinkage tends to be large. Further, it is more preferably 40 to 120 ° C.

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

(Winding process)
The winding step is a step of winding the obtained polyimide film and cooling it to room temperature. The winder may be one that is generally used, and can be wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress.

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

In the winding step, both ends of the polyimide film sandwiched by a tenter clip or the like when stretched and conveyed may be slit. It is preferable that the slit end of the polyimide film is finely cut within a width of 1 to 30 mm, then dissolved in a solvent and reused as a return material.

Each step from the solvent evaporation step to the winding step described above may be carried out in an air atmosphere or an inert gas atmosphere such as nitrogen gas. Further, each step, particularly the drying step and the stretching step, is performed in consideration of the explosive limit concentration of the solvent in the atmosphere.

(Heating process)
After the winding step, a heating step of further heat-treating the polyimide film dried in the second drying step is performed in order to promote imidization within the polymer chain molecule and between the polymer chain molecules to improve the mechanical properties. Is also good.

The second drying step may also serve as a heating step.

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

In the heating step, if the polyimide film is rapidly heated, problems such as an increase in surface defects occur. Therefore, it is preferable to appropriately select the heating method. Further, the heating step is preferably performed in a low oxygen atmosphere.

If the heating temperature in the second drying step and the heating step exceeds 450 ° C., the energy required for heating becomes very large, so that the manufacturing cost increases and the environmental load increases. Therefore, the heating temperature is 450 ° C. It is preferable to make the following.

After the drying step is completed, the polyimide film is characterized by containing an organic solvent having a boiling point of 80 ° C. or lower in the range of 0.1 to 2.0 g / m ² . The content of the organic solvent can be adjusted by changing the temperature, time, etc. of the drying step.

After the winding step, before or after the heating step, a step of slitting the widthwise end portion of the polyimide film, a step of removing static electricity when the polyimide film is charged, and the like are further performed. May be.

<Shape of polyimide film>
The polyimide film of the present invention is preferably long, specifically, has a length within the range of about 100 to 10,000 m, and is wound into a roll. The width of the polyimide 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.

<Use of polyimide film>
The polyimide film of the present invention can be preferably used as a film member of an image display device. The applicable device is not particularly limited, and examples thereof include 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, and a retardation film. .. From the viewpoint that the effect of the present invention can be obtained more efficiently, the polyimide film of the present invention is more preferably used as a base material of the transparent conductive film used for a touch panel.

<Transparent conductive film>
The transparent conductive film of the present invention is characterized by having the polyimide film of the present invention and a transparent conductive layer.

As an example of the configuration of the present invention, as shown in FIG. 1, the transparent conductive film 1 is provided with a surface protective layer 3 and a transparent conductive layer 4 laminated in this order on a polyimide film (base material) 2. Further, a surface protective layer 3 is provided on the other surface of the polyimide film (base material) 2.

The transparent conductive film of the present invention has a resistance value of 0.01 to 150 Ω / sq. Of the transparent conductive layer of the present application. It is preferably within the range of. More preferably, the resistance value of the transparent conductive layer is 0.1 to 100 Ω / sq. Is within the range of. The resistance value of the transparent conductive layer is 0.01Ω / sq. With the above, durability against keystrokes is obtained, and the resistance value is 150 Ω / sq. The following is preferable from the viewpoint of suppressing curl.

Further, the transparent conductive layer of the present application may satisfy the above resistance value, but preferably contains a copper mesh, copper is less likely to cause a migration phenomenon than other metals, and from the viewpoint of suppressing disconnection at the time of keystroke. preferable.

(Metal nanowires)
The metal nanowire is a conductive substance whose material is metal, whose shape is needle-shaped or thread-shaped, and whose diameter is nanometer-sized. The metal nanowires may be linear or curved. If a transparent conductive layer made of metal nanowires is used, the metal nanowires form a mesh, so that a good electric conduction path can be formed even with a small amount of metal nanowires, and electric resistance can be obtained. A small transparent conductive film can be obtained. Further, since the metal nanowires have a mesh shape, an opening can be formed in the gap between the meshes to obtain a transparent conductive film having high light transmittance.

The ratio of the thickness d to the length L (aspect ratio: L / d) of the metal nanowire is preferably in the range of 10 to 100,000, more preferably in the range of 50 to 100,000, and particularly preferably. Is in the range of 100 to 10,000. When metal nanowires having such a large aspect ratio are used, the metal nanowires can intersect well and a small amount of metal nanowires can exhibit high conductivity. As a result, a transparent conductive film having high light transmittance can be obtained.

In the present specification, the "thickness of metal nanowires" means the diameter of the metal nanowires when the cross section is circular, and the minor diameter when the cross section of the metal nanowires is elliptical. When it is a polygon, it means the longest diagonal line. The thickness and length of the metal nanowires can be confirmed by a scanning electron microscope or a transmission electron microscope.

The thickness of the metal nanowires is preferably less than 500 nm, more preferably less than 200 nm, particularly preferably in the range of 10 to 100 nm, and most preferably in the range of 10 to 50 nm. Within such a range, a transparent conductive layer having high light transmittance can be formed. Further, within such a range, it is more preferable from the viewpoint of the effect of the present invention. That is, the polyimide film of the present invention has improved durability against keystrokes even for finer metal nanowires, and the effect of the present invention is likely to be exhibited.

The length of the metal nanowires is preferably in the range of 2.5 to 1000 μm, more preferably in the range of 10 to 500 μm, and particularly preferably in the range of 20 to 100 μm. Within such a range, a transparent conductive film having high conductivity can be obtained.

As the metal constituting the metal nanowire, any suitable metal can be used as long as it is a highly conductive metal. Examples of the metal constituting the metal nanowire include silver, gold, copper, nickel and the like. Further, a material obtained by plating these metals (for example, gold plating) may be used. Of these, silver or copper is preferable from the viewpoint of conductivity.

Any suitable method can be adopted as the method for producing the metal nanowires. For example, a method of reducing silver nitrate in a solution, a method of applying an applied voltage or an electric current to the surface of the precursor from the tip of the probe, pulling out a metal nanowire at the tip of the probe, and continuously forming the metal nanowire. Can be mentioned. In the method of reducing silver nitrate in a solution, silver nanowires can be synthesized by liquid-phase reduction of a silver salt such as silver nitrate in the presence of a polyol such as ethylene glycol and polyvinylpyrrolidone.

Uniformly sized silver nanowires are available, for example, from Xia, Y. et al. etal. , Chem. Mater. (2002), 14, 4736-4745, Xia, Y. et al. etal. , Nano letters (2003) 3 (7), 955-960, can be mass-produced according to the method.

The transparent conductive layer can be formed by applying a composition for forming a transparent conductive layer containing the metal nanowires on the transparent base material. More specifically, a dispersion liquid (composition for forming a transparent conductive layer) in which the metal nanowires are dispersed in a solvent is applied onto the transparent substrate, and then the coated layer is dried to obtain a transparent conductive layer. Can be formed.

Examples of the solvent include water, alcohol solvents, ketone solvents, ether solvents, hydrocarbon solvents, aromatic solvents and the like. From the viewpoint of reducing the environmental load, it is preferable to use water.

The dispersion concentration of the metal nanowires in the composition for forming a transparent conductive layer containing the metal nanowires is preferably in the range of 0.1 to 1% by mass. Within such a range, a transparent conductive layer having excellent conductivity and light transmission can be formed.

The composition for forming a transparent conductive layer containing the metal nanowires may further contain any suitable additive depending on the purpose. Examples of the additive include a corrosion inhibitor for preventing corrosion of metal nanowires, a surfactant for preventing aggregation of metal nanowires, and the like. The type, number and amount of additives used can be appropriately set according to the purpose. In addition, the composition for forming a transparent conductive layer may contain any suitable binder resin, if necessary, as long as the effects of the present invention can be obtained.

Any suitable method can be adopted as a method for applying the composition for forming a transparent conductive layer containing the metal nanowires. Examples of the coating method include spray coating, bar coating, roll coating, die coating, inkjet coating, screen coating, dip coating, letterpress printing method, intaglio printing method, gravure printing method and the like.

As a method for drying the coating layer, any suitable drying method (for example, natural drying, blast drying, heat drying) can be adopted. For example, in the case of heat drying, the drying temperature is typically in the range of 100 to 200 ° C., and the drying time is typically in the range of 1 to 10 minutes.

When the transparent conductive layer contains metal nanowires, the thickness of the transparent conductive layer is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 3 μm, and particularly preferably in the range of 0.05 to 3 μm. Is in the range of 0.1 to 1 μm. Within such a range, a transparent conductive film having excellent conductivity and light transmittance can be obtained.

When the transparent conductive layer contains metal nanowires, the total light transmittance of the transparent conductive layer is preferably 85% or more, more preferably 90% or more, still more preferably 95% or more.

(Metal mesh)
The transparent conductive layer containing the metal mesh is formed by forming fine metal lines in a lattice pattern on the transparent base material. As the metal constituting the metal mesh, any suitable metal can be used as long as it is a highly conductive metal. Examples of the metal constituting the metal mesh include silver, gold, copper, nickel and the like. Further, a material obtained by plating these metals (for example, gold plating) may be used. Of these, copper is preferable, and migration phenomenon is unlikely to occur, and it is also preferable from the viewpoint of suppressing disconnection at the time of keystroke.

The transparent conductive layer containing the metal mesh can be formed by any suitable method. For the transparent conductive layer, for example, a photosensitive composition containing a silver salt (composition for forming a transparent conductive layer) is applied onto the laminate, and then exposure treatment and development treatment are performed to form a fine metal wire in a predetermined pattern. It can be obtained by forming in. Further, the transparent conductive layer can also be obtained by printing a paste containing metal fine particles (composition for forming a transparent conductive layer) on a predetermined pattern.

Details of such a transparent conductive film and a method for forming the same are described in, for example, Japanese Patent Application Laid-Open No. 2012-18634, and the description thereof is incorporated herein by reference. Further, as another example of the transparent conductive film composed of the metal mesh and the method for forming the transparent conductive film, the transparent conductive film described in JP-A-2003-331654 and the method for forming the transparent conductive film can be mentioned.

When the transparent conductive film contains a metal mesh, the thickness of the transparent conductive film is preferably in the range of 0.1 to 30 μm, more preferably in the range of 0.1 to 9 μm.

When the transparent conductive layer contains a metal mesh, the transmittance of the transparent conductive layer is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more.

<Touch panel>
The touch panel of the present invention is characterized by comprising the transparent conductive film of the present invention.
The touch panel of the present invention is not particularly limited as long as the shape of the pattern of the transparent conductive layer is a pattern that operates well as a touch panel (for example, a capacitive touch panel), but for example, Japanese Patent Application Laid-Open No. 2011-511357. Examples thereof include the patterns described in Japanese Patent Application Laid-Open No. 2010-164938, Japanese Patent Application Laid-Open No. 2008-310550, Japanese Patent Application Laid-Open No. 2003-511799, and Japanese Patent Application Laid-Open No. 2010-541109.

As shown in FIG. 2, in the touch panel, a transparent conductive film patterned on the x-axis and a transparent conductive film 1 patterned on the y-axis are laminated using an adhesive film 5, and a cover glass 6 is placed on the outermost surface. It can be manufactured by providing the touch panel, and the touch panel display device can be manufactured by combining the touch panel with the liquid crystal display device 7.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass".

[Example 1]
The structures of the compounds used in the following examples are listed below.

なお、上記の化合物の市販品の入手先は以下のとおりである。
酸無水物１：ダイキン工業社
酸無水物２：マナック株式会社
ジアミン１：ダイキン工業社
ジアミン２：三井化学ファイン株式会社
ジアミン７：和歌山精化株式会社
＜ポリイミドフィルム１の作製＞
（ポリイミド溶液Ａの調製）
乾燥窒素ガス導入管、冷却器、トルエンを満たしたＤｅａｎ−Ｓｔａｒｋ凝集器、撹拌機を備えた４口フラスコに、２，２−ビス（３，４−ジカルボキシフェニル）−１，１，１，３，３，３−ヘキサフルオロプロパン二無水物（酸無水物１）（ダイキン工業社製）２５．５９ｇ（５７．６ｍｍｏｌ）をＮ，Ｎ−ジメチルアセトアミド（１３４ｇ）に加え、窒素気流下、室温で撹拌した。

The sources of commercially available products of the above compounds are as follows.
Acid anhydride 1: Daikin anhydride Co., Ltd. Acid anhydride 2: Manac Co., Ltd. Diamine 1: Daikin Industries, Ltd. Diamine 2: Mitsui Kagaku Fine Co., Ltd. Diamine 7: Wakayama Seika Co., Ltd. <Preparation of polyimide film 1>
(Preparation of polyimide solution A)
2,2-Bis (3,4-dicarboxyphenyl) -1,1,1, in a four-necked flask equipped with a dry nitrogen gas introduction tube, a cooler, a Dean-Stark aggregator filled with toluene, and a stirrer. Add 25.59 g (57.6 mmol) of 3,3,3-hexafluoropropane dianhydride (acid anhydride 1) (manufactured by Daikin Industries, Ltd.) to N, N-dimethylacetamide (134 g) at room temperature under a nitrogen stream. Was stirred with.

To this, 19.2 g (60 mmol) of the 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl (diamine 1) (manufactured by Daikin Industries, Ltd.) was added, and the mixture was heated and stirred at 80 ° C. for 6 hours. Then, the outside temperature was heated to 190 ° C., and the water generated by imidization was azeotropically distilled off together with toluene. After continuing heating, refluxing and stirring for 6 hours, no water was generated. Subsequently, the mixture was heated for 7 hours while distilling off toluene, and after distilling off toluene, methanol was added to reprecipitate, and after the solid content was dried, a 12% by mass dichloromethane solution was used to prepare a polyimide solution A.

(Preparation of main doping)
A main dope for producing a crushed product having the following composition was prepared. First, dichloromethane (boiling point 40 ° C.) was added to the pressure dissolution tank. The polyimide solution A prepared above and the remaining components were put into a pressurized dissolution tank containing a solvent with stirring. This is heated and completely dissolved while stirring, and this is Azumi Filter Paper No. 1 manufactured by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to prepare the main dope for crushed product preparation.

(Composition of main doping)
Dichloromethane 330 parts by mass Polyimide solution A 100 parts by mass Inorganic fine particles (Aerosil R812, manufactured by Nippon Aerosil Co., Ltd.) 0.01 parts by mass (casting process)
The dope was then uniformly cast on the stainless steel belt support at a temperature of 30 ° C. and a width of 1500 mm using an endless belt casting device. The temperature of the stainless steel belt was controlled to 20 ° C.

(Peeling process)
On the stainless belt support, the film thickness at the time of casting was controlled to be 80 μm, evaporated for a predetermined drying time, and then peeled from the stainless belt support at a peeling tension of 60 N / m.

At this time, the residual solvent amount of dichloromethane in the casting film at the time of peeling was 5% by mass.

(Stretching process)
The peeled film was stretched 40 times in the width direction using a clip-type tenter while applying heat at 120 ° C.

(Drying process)
The stretched film was dried at a drying temperature of 120 ° C. until the residual solvent amount became 1% by mass to obtain a polyimide film having a dry film thickness of 63 μm. The obtained polyimide film was wound up to obtain a polyimide film 1.

<Preparation of polyimide films 2-14>
In the production of the polyimide film 1, the acid anhydride, the type of diamine, the type of organic solvent, the amount of residual solvent at the time of peeling, and the amount of residual solvent after drying were changed as shown in Tables 1 and 2. Polyimide films 2 to 14 were produced in the same manner as in the polyimide film 1 except for the above. In the preparation of the polyimide films 2 to 14, the acid anhydride and the diamine used as raw materials for the polyimide film used were the compounds shown in Table 1, and the same molar amount as that of the polyimide film 1 for mixing was used. The amount of residual solvent at the time of peeling and the amount of residual solvent after drying were adjusted by changing the drying air, the drying time, and the support temperature.

上記の各混合用ポリイミドフィルムは、幅１９００ｍｍ、長さ８０００ｍの長尺フィルムの形状で作製しポリイミドフィルム１〜１４を得た。なお、ポリイミドフィルム１〜１４は、沸点が８０℃以下の有機溶剤を０．１〜２．０ｇ／ｍ^２の範囲内で含有していた。

Each of the above-mentioned polyimide films for mixing was produced in the form of a long film having a width of 1900 mm and a length of 8000 m to obtain polyimide films 1 to 14. The polyimide films 1 to 14 contained an organic solvent having a boiling point of 80 ° C. or lower in the range of 0.1 to 2.0 g / m ² .

<Evaluation of polyimide film>
(Solubility)
Each polyimide resin used in the production of each polyimide film was dissolved in 100 g of dichloromethane at 60 ° C., and the upper limit of dissolution was measured. Table 1 shows the results of evaluating the solubility of each polyimide resin according to the following evaluation criteria.

◯: Solubility 1 g or more ×: Solubility less than 1 g (difference in surface elastic modulus)
The elastic modulus of the surface of each polyimide film was measured as follows. A Vickers indenter (tip ridge angle 90 °, tip radius of curvature 35 to 50 nm) was brought into contact with the sample surface using a micro surface hardness tester (Triboscope manufactured by Hysiron), and then the load was increased to 1 mN in 10 seconds. Hold for 5 seconds. The penetration depth of the Vickers indenter at this time is Dv0. After that, when the load was 0 mN, the force (Fv) and the penetration depth (Dv) for pushing back the Vickers indenter were measured, and the inclination was taken as the surface elastic modulus. This measurement was performed at 25 ° C. and 60% RH, and was expressed as an average value of 10 points. The value obtained by subtracting the value of the surface elastic modulus of the surface having a small surface elastic modulus from the value of the surface elastic modulus of the surface having a large surface elastic modulus was defined as the difference in the surface elastic modulus.

(Removability)
The peelability of each polyimide film in the casting film forming process was evaluated according to the following evaluation criteria.

◯: Normal production is possible Δ: Film peeling residue is likely to occur, which is a dangerous condition in manufacturing ×: The state of the film cannot be maintained and production is difficult. Table 2 shows the results of evaluation of the peelability of each polyimide film. Shown in.
<Manufacturing of transparent conductive film 1>
Next, an ultraviolet curable resin (JSR Opstar Z7527) and a surfactant (AGC Seimi Chemical's Surflon S-651) containing acrylic acid ester and amorphous silica as main components using microgravia on one side of the polyimide film 1 were used. ) Was applied to form a surface protective layer so as to have a thickness of 0.7 μm after drying, and the mixture was dried.

Then, using a high-pressure mercury lamp, the coating film was irradiated with ultraviolet rays at a light amount of 270 mJ / cm ² in the atmosphere to be cured, and a surface protective layer was formed on one side. Next, a surface protective layer was similarly formed on the surface opposite to the surface protective layer.

Next, a transparent conductive layer was formed.

Silver nanowires are available from Y. Sun, B. Gates, B.I. Mayers, & Y. Xia, "Crystalline silver nanowires by solution processing", Nanolets, (2002), 2 (2) After the method with polyols described in 165-168, ethylene glycol in the presence of polyvinylpyrrolidone (PVP). It is a nanowire synthesized by dissolving silver sulfate in water and reducing it. That is, in the present invention, nanowires synthesized by the modified polyol method described in Cambrios Technologies Corporation US Provisional Application No. 60 / 815,627 were used.

As a metal nanowire forming a transparent conductive layer, a silver nanowire having a minor axis diameter of about 70 to 80 nm and an aspect ratio of 100 or more synthesized by the above method is contained in an aqueous medium at 0.5% w / v. The aqueous dispersion composition (ClearOhmTM, Ink-A AQ manufactured by Cambrios Technologies Corporation) was applied onto the polyimide film 1 using a slot die coating machine so that the film thickness would be 1.5 μm, and the film was dried. Later, pressure treatment was performed at a pressure of 2000 kN / m ² to form a transparent conductive layer to obtain a transparent conductive film 1.

<Manufacturing of transparent conductive films 2 to 14>
The transparent conductive layer made of the transparent conductive film 1 was formed on the polyimide films 2 to 14, respectively, to prepare the transparent conductive films 2 to 14.

<Manufacturing of touch panel display device>
Touch panel members 1 to 14 were produced as shown in FIG. 3 using the transparent conductive films 1 to 14 patterned as described in JP-A-2010-541109.

Next, the touch panel members of Sony's 21.5-inch VAIO Tap21 (SVT21219DJB) that had been pasted together were peeled off, and the touch panel members produced above were pasted together to prepare touch panel display devices 1 to 14.

The following keystroke tests were performed on the touch panel display devices 1 to 14 produced in this manner, and then the resistance value change rate evaluation and the touch panel responsiveness evaluation were performed as follows.

(Keystroke test)
For the obtained touch panel display device, a keystroke tester 202 type-950-2 (manufactured by Touch Panel Laboratory Co., Ltd.) was used to input a pen from above the cover glass side under the conditions of a keystroke speed of 2 Hz and a load of 150 g. It was pressed 15,000 times. As the pen tip material of the input pen, a measuring board laid under the rubber is used as a glass substrate, the conductive mesh is placed on the glass substrate, and the input pen is pressed from above with a load of 300 g to slide a distance. The experiment was carried out using an experimental device capable of repeatedly sliding under the conditions of 5 cm and 1 second reciprocation (5 cm reciprocating in 1 second). The pen tip material of the input pen is polyacetal, and R is 0.8 mm.

(Evaluation of resistance value change rate)
Using a touch panel tester 001 type-29-2 (manufactured by Touch Panel Laboratory Co., Ltd.), the resistance value between terminals of the touch panel display device before and after the keystroke test was measured, and the resistance value change rate was evaluated based on the following evaluation criteria. ..

3: The rate of increase in surface resistance before and after the keystroke test indicates a value of less than 0.5% 2: The rate of increase in surface resistance before and after the keystroke test indicates a value of 0.5% or more and less than 1.5% 1 : The rate of increase in surface resistance before and after the keystroke test is 1.5% or more (touch panel responsiveness evaluation)
With the touch panel display device displayed after the keystroke test, the evaluator traced the touch panel screen from the left edge to the right edge with a finger to evaluate whether the pointer operated based on the following evaluation criteria.

When 3: 5 evaluators performed the above work 20 times each, the pointer responded 100 times out of 100 times.

When 2: 5 evaluators performed the above work 20 times each, the pointer responded 99 times out of 100 times.

When 1: 5 evaluators performed the above work 20 times each, the pointer responded 98 times or less out of 100 times.

The evaluation results for each item are shown in Table 3.

表３に示されるように、本発明のタッチパネルは、打鍵試験前後での抵抗変化率が小さく、応答性も良いことがわかる。

As shown in Table 3, it can be seen that the touch panel of the present invention has a small resistance change rate before and after the keystroke test and good responsiveness.

1 Transparent conductive film 2 Polyimide film (base material)
3 Surface protective layer 4 Transparent conductive layer 5 Adhesive film 6 Cover glass 7 Touch panel member 8 Liquid crystal display device 101 Melting pot 103, 106, 112, 115 Filter 104, 113 Stock pot 102, 105, 111, 114 Liquid transfer pump 108, 116 Conduit 110 Additive charging kettle 120 Confluence pipe 121 Mixer 130 Pressurized 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 Winding device 141 Stock Cauldron 143 Pump 144 Filter

Claims (4)

A polyimide film containing a polyimide that is dissolved in the range of 1 to 50 g with respect to 100 g of dichloromethane at 25 ° C.
A surface elastic modulus of the surface (A) one of said polyimide film, Ri difference der following 2GPa the surface elastic modulus of the other surface (B), and,
Polyimide film boiling is characterized that you containing 80 ° C. or less of the organic solvent in the range of 0.1 to 2.0 g / ^{m 2.} A method for producing a polyimide film for producing the polyimide film according to claim 1 .
A step of preparing a doping containing the polyimide and an organic solvent having a boiling point of 80 ° C. or lower.
A step of casting the dope onto a support to form a film,
The step of peeling the film from the support,
Including the step of drying the peeled film, and
In the step of peeling the film from the support, the residual solvent amount of the organic solvent having a boiling point of 80 ° C. or lower is in the range of 5 to 40% by mass, or in the range of 100 to 200% by mass. A method for producing a polyimide film. A transparent conductive film having the polyimide film according to claim 1 and a transparent conductive layer. A touch panel comprising the transparent conductive film according to claim 3 .

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