JP2007169304A - Polyimide precursor, polyimide, polyimide-based plastic substrate plate and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyimide excellent in transparency, having high toughness and a high glass transition temperature jointly, and useful as an electrical insulation film in various electronic devices, a substrate for a liquid crystal display, a substrate for an organic EL display, a substrate for an electronic paper, a substrate for solar cells and especially as a plastic substrate for a flexible film liquid crystal display, its precursor, the plastic substrate by using the polyimide and a method for producing the same. <P>SOLUTION: This polyimide precursor having a structural unit having a specific tetracarboxylic acid dianhydride expressed by general formula (1) and a specific alicyclic diamine as constituting components, the polyimide obtained by imidizing the polyimide precursor and the polyimide-based plastic substrate plate obtained by using the polyimide are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention has high transparency, high toughness, and a high glass transition temperature. Electrical insulating films for various electronic devices, substrates for liquid crystal displays, substrates for organic luminescence displays, substrates for electronic paper, substrates for solar cells, particularly flexible. The present invention relates to a polyimide useful as a plastic substrate for a film liquid crystal display, a precursor thereof, and a plastic substrate using the polyimide.

  Currently, glass substrates are used for liquid crystal displays, but with the trend toward larger screens in recent years, problems of weight reduction and productivity improvement have become serious. As a solution to this, as a substitute for a heavy glass substrate, it is required to adopt a plastic substrate that is lighter and easier to mold. A transparent and sufficiently tough plastic substrate makes it possible to realize a flexible display panel that can be bent and rolled.

  However, the plastic substrate has the disadvantage that it is inferior in heat resistance to the glass substrate at the same time. For example, when a plastic substrate for a panel is applied to a full color TFT type liquid crystal panel, the plastic substrate must withstand a high temperature of 200 to 220 ° C. in the manufacturing process. However, vinyl polymers and polycarbonates typified by polymethyl methacrylate have high transparency, but the glass transition is inferior in heat resistance at around 100 ° C. and 150 ° C., respectively. At present, a material that satisfies the required characteristics as a plastic substrate having both heat resistance, transparency and toughness is not yet known.

  On the other hand, a polyimide resin is excellent in heat resistance, and is therefore a candidate for a plastic substrate material. Generally, polyimide has a high degree of polymerization that is easily obtained by equimolar reaction of an aromatic tetracarboxylic dianhydride such as pyromellitic anhydride and an aromatic diamine such as diaminodiphenyl ether in an aprotic polar solvent such as dimethylacetamide. The polyimide precursor is formed into a film and cured by heating.

  These wholly aromatic polyimides have not only excellent heat resistance but also chemical resistance, radiation resistance, electrical insulation, mechanical properties, etc., so they can be used for flexible printed circuit boards and tape automation bonding. Currently, it is widely used in various electronic devices such as base materials, protective films for semiconductor elements, and interlayer insulating films for integrated circuits.

  However, these wholly aromatic polyimides have a strong electron absorption transition from the ultraviolet region to the visible region, and thus have a drawback that the transparency of the film is extremely low. This is due to intramolecular conjugation through aromatic groups in the polyimide chain and intramolecular / intermolecular charge transfer interaction (see Non-Patent Document 1).

  In order to make the polyimide film transparent, it is effective to use an aliphatic or alicyclic monomer in one or both of acid dianhydride and diamine. As a result, intramolecular conjugation and charge transfer interaction of the polyimide chain are hindered, and as a result, the transparency of the polyimide film and its precursor film in the entire ultraviolet / visible region is dramatically increased. From the viewpoint of chemical and physical heat resistance, alicyclic monomers are often used rather than aliphatic structures.

  If the aromatic tetracarboxylic dianhydride is replaced with an alicyclic / aliphatic tetracarboxylic acid, there is a problem in polymerization reactivity, and a high molecular weight body having a sufficient molecular weight cannot be obtained. In this case, only those with insufficient toughness can be obtained. On the other hand, when the diamine is replaced with an alicyclic / aliphatic diamine, when the polyimide precursor is polymerized from various tetracarboxylic dianhydrides, salt formation occurs at the initial stage of the polymerization reaction, and the polymerization reaction is continued for a long time until the salt is dissolved. In addition, for example, in the case of a combination of pyromellitic dianhydride and trans-1,4-diaminocyclohexane, the polymerization reaction proceeds at all because of the formation of a very strong salt. A serious problem arises. This is because the basicity of the alicyclic / aliphatic diamine is much higher than that of the commonly used aromatic diamine.

  Non-Patent Document 2 discloses an interfacial polymerization method as a method for avoiding salt formation when using an alicyclic / aliphatic diamine. In this method, tetracarboxylic dianhydride and alcohol are first reacted to form a dialkyl ester of tetracarboxylic acid, which is then chlorinated and dissolved in an oil layer, and this and an aliphatic diamine dissolved in an alkaline aqueous solution are mixed with oil / water. Polymerization is performed at the interface to obtain an alkyl ester of polyamic acid. This is thermally imidized to obtain an alicyclic polyimide.

  However, in this polymerization method, the production process is complicated and it is difficult to obtain a polyimide precursor having a high degree of polymerization, and the variation in molecular weight from batch to batch is also large. Further, the interfacial polycondensation method has low productivity and is not practical. Further, as a serious problem, chlorine generated in the interfacial polymerization method remains in the polyimide precursor and cannot be washed and removed, which is not preferable for use as an electronic material.

  Therefore, there is a need for a new polyimide having a high molecular weight alicyclic structure that is suitable for electronic materials such as display substrate materials, has excellent transparency and heat resistance, and has sufficient toughness.

Prog. Polym. Sci., 26, 259 (2001) High Perform. Polym., 10, 11 (1998)

  The present invention has high transparency, high toughness, and a high glass transition temperature. Electrical insulating films in various electronic devices, liquid crystal display substrates, organic electroluminescence display substrates, electronic paper substrates, solar cell substrates, particularly flexible films. An object of the present invention is to provide a polyimide useful as a plastic substrate for a liquid crystal display and a precursor thereof, a plastic substrate using the polyimide, and a method for producing the same.

In view of the above problems, as a result of intensive research, the following knowledge was obtained.
(1) In the polyimide precursor of the present invention, salt formation is suppressed despite the diamine component being an alicyclic diamine, and a polyimide precursor having a high degree of polymerization is obtained.
(2) Moreover, the said polyimide precursor and the polyimide obtained by imidating this should be organic solvent soluble.
(3) Therefore, it should be easy to handle and suitable for molding of polyimide.
(4) The polyimide has characteristics as a plastic substrate that requires low water absorption, high transparency, high heat resistance, and the like.
Based on this knowledge, the present invention has been completed.

［式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、同一又は異なって、水素原子、炭素数１〜１２の直鎖状若しくは分岐鎖状のアルキル基、炭素数２〜１２の直鎖状若しくは分岐鎖状のアルケニル基、炭素数１〜１２の直鎖状若しくは分岐鎖状のアルコキシ基、炭素数４〜１２のシクロアルキル基、ニトリル基、ニトロ基、カルボキシル基、アミド基、ハロゲン原子、又は、炭素数１〜１２の直鎖状若しくは分岐鎖状のアルキル基、炭素数２〜１２の直鎖状若しくは分岐鎖状のアルケニル基、炭素数１〜１２の直鎖状若しくは分岐鎖状のアルコキシ基、ニトリル基、ニトロ基、カルボキシル基、アミド基及びハロゲン原子からなる群から選ばれる置換基を１個以上有していてもよい炭素数６〜１２の脂環族基若しくは炭素数６〜１２の芳香族基を表す。Ｘは、エーテル基、チオエーテル基、カルボニル基又はスルホニル基を表す。Ｚは、炭素数１〜１２の直鎖状若しくは分岐鎖状のアルキル基、炭素数１〜１２の直鎖状若しくは分岐鎖状のアルコキシ基、炭素数４〜１２のシクロアルキル基、ニトリル基、ニトロ基、カルボキシル基、アミド基及びハロゲン原子からなる群から選ばれる置換基を１個以上有していてもよい炭素数６〜２４の２価の脂環族基を表す。尚、両末端のベンゼン環に結合する２つのフェノキシカルボニル基の置換位置は、それぞれ同一又は異なって、カルバモイル基に対してｍ位又はｐ位である。］
で表される構造単位を有するポリイミド前駆体。 That is, the present invention provides the following inventions.
[Claim 1] General formula (1)

[Wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear chain having 2 to 12 carbon atoms. Or branched alkenyl group, linear or branched alkoxy group having 1 to 12 carbon atoms, cycloalkyl group having 4 to 12 carbon atoms, nitrile group, nitro group, carboxyl group, amide group, halogen atom Or a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, a linear or branched chain having 1 to 12 carbon atoms An alicyclic group having 6 to 12 carbon atoms or 6 carbon atoms which may have one or more substituents selected from the group consisting of an alkoxy group, a nitrile group, a nitro group, a carboxyl group, an amide group and a halogen atom. Table of 12 aromatic groups . X represents an ether group, a thioether group, a carbonyl group or a sulfonyl group. Z is a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkoxy group having 1 to 12 carbon atoms, a cycloalkyl group having 4 to 12 carbon atoms, a nitrile group, A bivalent alicyclic group having 6 to 24 carbon atoms which may have one or more substituents selected from the group consisting of a nitro group, a carboxyl group, an amide group and a halogen atom. The substitution positions of the two phenoxycarbonyl groups bonded to the benzene rings at both ends are the same or different and are the m-position or p-position with respect to the carbamoyl group. ]
The polyimide precursor which has a structural unit represented by these.

[Item 2] R ¹ , R ² , R ³ and R ⁴ are the same or different and are a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear chain having 2 to 12 carbon atoms. The polyimide precursor of claim | item 1 represented by a linear or branched alkenyl group or a C6-C12 cycloalkyl group.

  [Item 3] The polyimide precursor according to any one of Items 1 or 2, wherein X is a sulfonyl group or an ether group.

［式中、Ｒ^５、Ｒ^６、Ｒ^７及びＲ^８は、互いに同一又は異なって、それぞれ水素原子、メチル基又はエチル基を表す。Ａ^１及びｍ個のＡ^２は、同一又は異なって、それぞれ直接結合、又は炭素数１〜６のアルキリデン基を表す。ｍは、１又は２の整数を表す。］
で表される項１〜３のいずれかに記載のポリイミド前駆体。 [Claim 4] Z is the general formula (2).

[Wherein, R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different from each other and each represents a hydrogen atom, a methyl group or an ethyl group. A ¹ and m A ² are the same or different and each represents a direct bond or an alkylidene group having 1 to 6 carbon atoms. m represents an integer of 1 or 2. ]
The polyimide precursor in any one of claim | item 1-3 represented by these.

[Item 5] The polyimide precursor according to Item 4, wherein the configuration of A ¹ and A ² is a trans configuration, or the configuration of two A ² is a trans configuration.

  CLAIM | ITEM 6 The polyimide precursor in any one of claim | item 1 -5 which does not contain an amine salt substantially.

  CLAIM | ITEM 7 The polyimide precursor in any one of claim | item 1 -6 whose intrinsic viscosity is 0.4 dL / g or more.

  [Item 8] A polyimide precursor varnish comprising the polyimide precursor according to any one of Items 1 to 7 and an organic solvent.

［式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｘ及びＺは、一般式（１）におけるものと同義である。］
で表される構造単位を有するポリイミド。 [Item 9] General formula (3) obtained by imidizing the polyimide precursor according to any one of Items 1 to 7.

^{Wherein, R 1, R 2, R} 3, R 4, X and Z have the same meanings as in the general formula (1). ]
A polyimide having a structural unit represented by:

  CLAIM | ITEM 10 The polyimide of claim | item 9 whose water absorption is 2% or less.

  [Item 11] The polyimide according to Item 9 or 10, wherein the glass transition temperature is 200 ° C. or more, the light transmittance at a wavelength of 400 nm is 60% or more, the birefringence is 0.1 or less, and the elongation at break is 5% or more.

  [Item 12] A polyimide varnish comprising the polyimide according to any one of Items 9 to 11 and an organic solvent.

  CLAIM | ITEM 13 The polyimide molded body which consists of a polyimide of claim | item 9-11.

  [Item 14] The polyimide molded body according to item 13, wherein the polyimide molded body is in the form of a layer, a film, a film, or a sheet.

  [Item 15] A plastic substrate using the polyimide molded article according to item 14.

  [Item 16] The plastic substrate according to item 15, which is used for a display element.

  [Item 17] The plastic substrate according to item 16, wherein the display element is a liquid crystal display or an organic electroluminescence display.

  CLAIM | ITEM 18 The display element provided with the plastic substrate in any one of claim | item 15 -17.

CLAIM | ITEM 19 It is a manufacturing method of the plastic substrate in any one of claim | item 15-17, Comprising: The process of apply | coating the polyimide precursor varnish of claim | item 8 or the polyimide varnish of claim | item 12 on a support body. A step of drying, curing, and a step of peeling the polyimide molded body from the support,
A method of manufacturing a plastic substrate.

  Since the polyimide precursor of the present invention is excellent in solvent solubility, has a high degree of polymerization, and does not substantially contain a salt, the polyimide obtained from the polyimide precursor is excellent in heat resistance, transparency and mechanical properties. ing. In addition, a plastic substrate using the polyimide can be suitably used as a substrate for an electronic device, particularly as a plastic for a display element, using the characteristics.

［式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４及びＸは、一般式（１）におけるものと同義である。］ <Polyimide precursor>
The polyimide precursor of the present invention can be obtained by polymerizing an ester group-containing tetracarboxylic dianhydride represented by the following general formula (4) and an alicyclic diamine.

[Wherein, R ¹ , R ² , R ³ , R ⁴ and X have the same meaning as in general formula (1). ]

［式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４及びＸは一般式（１）中におけるものと同義である。］ The manufacturing method of the ester group containing tetracarboxylic dianhydride which concerns is not specifically limited, It can manufacture by a conventionally well-known method. For example, it can be produced by esterifying a trimellitic anhydride and a bisphenol compound represented by the following general formula (5).

[Wherein, R ¹ , R ² , R ³ , R ⁴ and X have the same meaning as in general formula (1). ]

Among the specific examples of the bisphenol compound represented by the general formula (5), examples of the compound in which X is a sulfonyl group include bis (4-hydroxyphenyl) sulfone and bis (4-hydroxy-3-methylphenyl). ) Sulfone, bis (4-hydroxy-3-ethylphenyl) sulfone, bis (4-hydroxy-3-propylphenyl) sulfone, bis (4-hydroxy-3-butylphenyl) sulfone, bis (4-hydroxy-3-) Pentylphenyl) sulfone, bis (4-hydroxy-3-hexylphenyl) sulfone, bis (4-hydroxy-3-heptylphenyl) sulfone, bis (4-hydroxy-3-octylphenyl) sulfone, bis (4-hydroxy- 3-nonylphenyl) sulfone, bis (4-hydroxy-3-decylphenyl) sulfone Hong, bis (4-hydroxy-3-undecylphenyl) sulfone, bis (4-hydroxy-3-dodecylphenyl) sulfone, bis (4-hydroxy-3,5-dimethylphenyl) sulfone, bis (4-hydroxy- 3,5-diethylphenyl) sulfone, bis (4-hydroxy-3, -ethyl-5-methyl) sulfone, bis (4-hydroxy-3,5-dipropylphenyl) sulfone, bis (4-hydroxy-3, 5-dibutylphenyl) sulfone, bis (4-hydroxy-3,5-dipentylphenyl) sulfone, bis (4-hydroxy-3,5-dihexylphenyl) sulfone, bis (4-hydroxy-3,5-diheptylphenyl) ) Sulfone, bis (4-hydroxy-3,5-dioctylphenyl) sulfone, bis (4-hydro) Cis-3,5-dinonylphenyl) sulfone, bis (4-hydroxy-3,5-didecylphenyl) sulfone, bis (4-hydroxy-3,5-diundecylphenyl) sulfone, bis (4-hydroxy-) 3,5-didodecylphenyl) sulfone, bis (4-hydroxy-3-vinylphenyl) sulfone, bis (4-hydroxy-3,5-divinylphenyl) sulfone, bis (4-hydroxy-3-allylphenyl) sulfone Alkyl or alkenyl substituents such as bis (4-hydroxy-3,5-diallylphenyl) sulfone;
Bis (4-hydroxy-3-methoxyphenyl) sulfone, bis (4-hydroxy-3-ethoxyphenyl) sulfone, bis (4-hydroxy-3-propoxyphenyl) sulfone, bis (4-hydroxy-3-butoxyphenyl) Sulfone, bis (4-hydroxy-3-pentyloxyphenyl) sulfone, bis (4-hydroxy-3-hexyloxyphenyl) sulfone, bis (4-hydroxy-3-heptyloxyphenyl) sulfone, bis (4-hydroxy) -3-octyloxyphenyl) sulfone, bis (4-hydroxy-3-nonyloxyphenyl) sulfone, bis (4-hydroxy-3-decyloxyphenyl) sulfone, bis (4-hydroxy-3-undecyloxyphenyl) Sulfone, bis (4-hydroxy-3-do Siloxyphenyl) sulfone, bis (4-hydroxy-3,5-dimethoxyphenyl) sulfone, bis (4-hydroxy-3,5-diethoxyphenyl) sulfone, bis (4-hydroxy-3,5-dipropoxyphenyl) ) Sulfone, bis (4-hydroxy-3,5-dibutoxyphenyl) sulfone, bis (4-hydroxy-3,5-dipentyloxyphenyl) sulfone, bis (4-hydroxy-3,5-dihexyloxyphenyl) Sulfone, bis (4-hydroxy-3,5-diheptyloxyphenyl) sulfone, bis (4-hydroxy-3,5-dioctyloxyphenyl) sulfone, bis (4-hydroxy-3,5-dinonyloxyphenyl) Sulfone, bis (4-hydroxy-3,5-didecyloxyphenyl) sulfone Bis (4-hydroxy-3,5-diundecyl oxyphenyl) sulfone, bis (4-hydroxy-3,5-di-dodecyloxy-phenyl) sulfone, alkoxy substitution products and the like;
Bis (4-hydroxy-3-cyclobutylphenyl) sulfone, bis (4-hydroxy-3-cyclopentylphenyl) sulfone, bis (4-hydroxy-3-cyclohexylphenyl) sulfone, bis (4-hydroxy-3-cycloheptyl) Phenyl) sulfone, bis (4-hydroxy-3-cyclooctylphenyl) sulfone, bis (4-hydroxy-3-cyclononylphenyl) sulfone, bis (4-hydroxy-3-decabitronnaphthylphenyl) sulfone, bis (4 -Hydroxy-3,5-dicyclobutylphenyl) sulfone, bis (4-hydroxy-3,5-dicyclopentylphenyl) sulfone, bis (4-hydroxy-3,5-dicyclohexylphenyl) sulfone, bis (4-bitroxy) -3-Cyclohexyl-5-methyl Phenyl) sulfone, bis (4-hydroxy-3,5-dicycloheptylphenyl) sulfone, bis (4-hydroxy-3,5-dicyclooctylphenyl) sulfone, bis (4-hydroxy-3,5-dicyclo) Cycloalkyl substituents such as nonylphenyl) sulfone, bis (4-hydroxy-3,5-didecabitronaphthylphenyl) sulfone, and the like;
Bis (4-hydroxy-3-phenylphenyl) sulfone, bis (4-hydroxy-3,5-diphenylphenyl) sulfone, bis (4-hydroxy-3-naphthylphenyl) sulfone, bis (4-hydroxy-3,5 -Aromatic substituents such as dinaphthylphenyl) sulfone;
Bis (4-hydroxy-3-cyanophenyl) sulfone, bis (4-hydroxy-3-nitrophenyl) sulfone, bis (4-hydroxy-3-carboxyphenyl) sulfone, bis (4-hydroxy-3-halogenophenyl) Sulfone, bis (4-hydroxy-3,5-dicyanophenyl) sulfone, bis (4-hydroxy-3,5-dinitrophenyl) sulfone, bis (4-hydroxy-3,5-dicarboxyphenyl) sulfone, bis ( 4-hydroxy-3,5-dihalogenophenyl) sulfone, and the like.

Examples of the bisphenol compound in which X is an ether group include bis (4-hydroxyphenyl) ether, bis (4-hydroxy-3-methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, Bis (4-hydroxy-3-propylphenyl) ether, bis (4-hydroxy-3-butylphenyl) ether, bis (4-hydroxy-3-pentylphenyl) ether, bis (4-hydroxy-3-hexylphenyl) Ether, bis (4-hydroxy-3-heptylphenyl) ether, bis (4-hydroxy-3-octylphenyl) ether, bis (4-hydroxy-3-nonylphenyl) ether, bis (4-hydroxy-3-decyl) Phenyl) ether, bis (4-hydroxy-3-undecylsulfate) Nyl) ether, bis (4-hydroxy-3-dodecylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxy-3,5-diethylphenyl) ether, bis (4 -Hydroxy-3, -ethyl-5-methyl) ether bis (4-hydroxy-3,5-dipropylphenyl) ether, bis (4-hydroxy-3,5-dibutylphenyl) ether, bis (4-hydroxy- 3,5-dipentylphenyl) ether, bis (4-hydroxy-3,5-dihexylphenyl) ether, bis (4-hydroxy-3,5-diheptylphenyl) ether, bis (4-hydroxy-3,5- Dioctylphenyl) ether, bis (4-hydroxy-3,5-dinonylphenyl) ether, bis ( -Hydroxy-3,5-didecylphenyl) ether, bis (4-hydroxy-3,5-diundecylphenyl) ether, bis (4-hydroxy-3,5-didodecylphenyl) ether, bis (4-hydroxy) -3-vinylphenyl) ether, bis (4-hydroxy-3,5-divinylphenyl) ether, bis (4-hydroxy-3-allylphenyl) ether, bis (4-hydroxy-3,5-diallylphenyl) ether Alkyl or alkenyl substituents such as
Bis (4-hydroxy-3-methoxyphenyl) ether, bis (4-hydroxy-3-ethoxyphenyl) ether, bis (4-hydroxy-3-propoxyphenyl) ether, bis (4-hydroxy-3-butoxyphenyl) Ether, bis (4-hydroxy-3-pentyloxyphenyl) ether, bis (4-hydroxy-3-hexyloxyphenyl) ether, bis (4-hydroxy-3-heptyloxyphenyl) ether, bis (4-hydroxy) -3-octyloxyphenyl) ether, bis (4-hydroxy-3-nonyloxyphenyl) ether, bis (4-hydroxy-3-decyloxyphenyl) ether, bis (4-hydroxy-3-undecyloxyphenyl) Ether, bis (4-hydroxy-3-do Siloxyphenyl) ether, bis (4-hydroxy-3,5-dimethoxyphenyl) ether, bis (4-hydroxy-3,5-diethoxyphenyl) ether, bis (4-hydroxy-3,5-dipropoxyphenyl) ) Ether, bis (4-hydroxy-3,5-dibutoxyphenyl) ether, bis (4-hydroxy-3,5-dipentyloxyphenyl) ether, bis (4-hydroxy-3,5-dihexyloxyphenyl) Ether, bis (4-hydroxy-3,5-diheptyloxyphenyl) ether, bis (4-hydroxy-3,5-dioctyloxyphenyl) ether, bis (4-hydroxy-3,5-dinonyloxyphenyl) Ether, bis (4-hydroxy-3,5-didecyloxyphenyl) ether Bis (4-hydroxy-3,5-diundecyl oxyphenyl) ether, bis (4-hydroxy-3,5-di-dodecyloxy-phenyl) ether, alkoxy substituted compounds and the like;
Bis (4-hydroxy-3-cyclobutylphenyl) ether, bis (4-hydroxy-3-cyclopentylphenyl) ether, bis (4-hydroxy-3-cyclohexylphenyl) ether, bis (4-hydroxy-3-cycloheptyl) Phenyl) ether, bis (4-hydroxy-3-cyclooctylphenyl) ether, bis (4-hydroxy-3-cyclononylphenyl) ether, bis (4-hydroxy-3-decabitronnaphthylphenyl) ether, bis (4 -Hydroxy-3,5-dicyclobutylphenyl) ether, bis (4-hydroxy-3,5-dicyclopentylphenyl) ether, bis (4-hydroxy-3,5-dicyclohexylphenyl) ether, bis (4-bitoxy) -3-Cyclohexyl-5-methyl Phenyl) ether, bis (4-hydroxy-3,5-dicycloheptylphenyl) ether, bis (4-hydroxy-3,5-dicyclooctylphenyl) ether, bis (4-hydroxy-3,5-dicyclo) Cycloalkyl substituents such as nonylphenyl) ether, bis (4-hydroxy-3,5-didecabitronaphtylphenyl) ether;
Bis (4-hydroxy-3-phenylphenyl) ether, bis (4-hydroxy-3,5-diphenylphenyl) ether, bis (4-hydroxy-3-naphthylphenyl) ether, bis (4-hydroxy-3,5) -Dinaphthylphenyl) ether, bis (4-hydroxy-3-cyanophenyl) ether, bis (4-hydroxy-3-nitrophenyl) ether, bis (4-hydroxy-3-carboxyphenyl) ether, bis (4- Hydroxy-3-halogenophenyl) ether, bis (4-hydroxy-3,5-dicyanophenyl) ether, bis (4-hydroxy-3,5-dinitrophenyl) ether, bis (4-hydroxy-3,5-di) Carboxyphenyl) ether, bis (4-hydroxy-3,5-dihalogenopheni ) Ether, and the like.

Examples of the bisphenol compound in which X is a thioether group include bis (4-hydroxyphenyl) thioether, bis (4-hydroxy-3-methylphenyl) thioether, bis (4-hydroxy-3-ethylphenyl) thioether, Bis (4-hydroxy-3-propylphenyl) thioether, bis (4-hydroxy-3-butylphenyl) thioether, bis (4-hydroxy-3-pentylphenyl) thioether, bis (4-hydroxy-3-hexylphenyl) Thioether, bis (4-hydroxy-3-heptylphenyl) thioether, bis (4-hydroxy-3-octylphenyl) thioether, bis (4-hydroxy-3-nonylphenyl) thioether, bis (4-hydroxy-3-decyl) Phenyl) thio Ether, bis (4-hydroxy-3-undecylphenyl) thioether, bis (4-hydroxy-3-dodecylphenyl) thioether, bis (4-hydroxy-3,5-dimethylphenyl) thioether, bis (4-hydroxy- 3,5-diethylphenyl) thioether, bis (4-hydroxy-3, -ethyl-5-methyl) thioether, bis (4-hydroxy-3,5-dipropylphenyl) thioether, bis (4-hydroxy-3, 5-dibutylphenyl) thioether, bis (4-hydroxy-3,5-dipentylphenyl) thioether, bis (4-hydroxy-3,5-dihexylphenyl) thioether, bis (4-hydroxy-3,5-diheptylphenyl) ) Thioether, bis (4-hydroxy-3,5-dio Tilphenyl) thioether, bis (4-hydroxy-3,5-dinonylphenyl) thioether, bis (4-hydroxy-3,5-didecylphenyl) thioether, bis (4-hydroxy-3,5-diundecylphenyl) Thioether, bis (4-hydroxy-3,5-didodecylphenyl) thioether, bis (4-hydroxy-3-vinylphenyl) thioether, bis (4-hydroxy-3,5-divinylphenyl) thioether, bis (4- Alkyl or alkenyl substituents such as hydroxy-3-allylphenyl) sulfone, bis (4-hydroxy-3,5-diallylphenyl) thioether;
Bis (4-hydroxy-3-methoxyphenyl) thioether, bis (4-hydroxy-3-ethoxyphenyl) thioether, bis (4-hydroxy-3-propoxyphenyl) thioether, bis (4-hydroxy-3-butoxyphenyl) Thioether, bis (4-hydroxy-3-pentyloxyphenyl) thioether, bis (4-hydroxy-3-hexyloxyphenyl) thioether, bis (4-hydroxy-3-heptyloxyphenyl) thioether, bis (4-hydroxy -3-octyloxyphenyl) thioether, bis (4-hydroxy-3-nonyloxyphenyl) thioether, bis (4-hydroxy-3-decyloxyphenyl) thioether, bis (4-hydroxy-3-undecyloxyphenyl) Thioether, bis (4-hydroxy-3-dodecyloxyphenyl) thioether, bis (4-hydroxy-3,5-dimethoxyphenyl) thioether, bis (4-hydroxy-3,5-diethoxyphenyl) thioether, bis (4 -Hydroxy-3,5-dipropoxyphenyl) thioether, bis (4-hydroxy-3,5-dibutoxyphenyl) thioether, bis (4-hydroxy-3,5-dipentyloxysiphenyl) thioether, bis (4- Hydroxy-3,5-dihexyloxyphenyl) thioether, bis (4-hydroxy-3,5-diheptyloxyphenyl) thioether, bis (4-hydroxy-3,5-dioctyloxyphenyl) thioether, bis (4-hydroxy) -3,5-dinonyloxyph Nyl) thioether, bis (4-hydroxy-3,5-didecyloxyphenyl) thioether, bis (4-hydroxy-3,5-diundecyloxyphenyl) thioether, bis (4-hydroxy-3,5-didodecyl) Alkoxy substituted products such as oxyphenyl) thioether;
Bis (4-hydroxy-3-cyclobutylphenyl) thioether, bis (4-hydroxy-3-cyclopentylphenyl) thioether, bis (4-hydroxy-3-cyclohexylphenyl) thioether, bis (4-hydroxy-3-cycloheptyl) Phenyl) thioether, bis (4-hydroxy-3-cyclooctylphenyl) thioether, bis (4-hydroxy-3-cyclononylphenyl) thioether, bis (4-hydroxy-3-decabitronnaphthylphenyl) thioether, bis (4 -Hydroxy-3,5-dicyclobutylphenyl) thioether, bis (4-hydroxy-3,5-dicyclopentylphenyl) thioether, bis (4-hydroxy-3,5-dicyclohexylphenyl) thioether, bis (4- Troxy-3-cyclohexyl-5-methylphenyl) thioether, bis (4-hydroxy-3,5-dicycloheptylphenyl) thioether, bis (4-hydroxy-3,5-dicyclooctylphenyl) thioether, bis (4 Cycloalkyl substituents such as -hydroxy-3,5-dicyclononylphenyl) thioether, bis (4-hydroxy-3,5-didecavitronylphenyl) thioether;
Bis (4-hydroxy-3-phenylphenyl) thioether, bis (4-hydroxy-3,5-diphenylphenyl) thioether, bis (4-hydroxy-3-naphthylphenyl) thioether, bis (4-hydroxy-3,5 -Aromatic substituents such as dinaphthylphenyl) thioether;
Bis (4-hydroxy-3-cyanophenyl) thioether, bis (4-hydroxy-3-nitrophenyl) thioether, bis (4-hydroxy-3-carboxyphenyl) thioether, bis (4-hydroxy-3-halogenophenyl) Thioether, bis (4-hydroxy-3,5-dicyanophenyl) thioether, bis (4-hydroxy-3,5-dinitrophenyl) thioether, bis (4-hydroxy-3,5-dicarboxyphenyl) thioether, bis ( 4-hydroxy-3,5-dihalogenophenyl) thioether, and the like.

Examples of the bisphenol compound in which X is a thioether group include bis (4-hydroxyphenyl) ketone, bis (4-hydroxy-3-methylphenyl) ketone, bis (4-hydroxy-3-ethylphenyl) ketone, Bis (4-hydroxy-3-propylphenyl) ketone, bis (4-hydroxy-3-butylphenyl) ketone, bis (4-hydroxy-3-pentylphenyl) ketone, bis (4-hydroxy-3-hexylphenyl) Ketone, bis (4-hydroxy-3-heptylphenyl) ketone, bis (4-hydroxy-3-octylphenyl) ketone, bis (4-hydroxy-3-nonylphenyl) ketone, bis (4-hydroxy-3-decyl) Phenyl) ketone, bis (4-hydroxy-3-undecylphenyl) ketone, bi (4-hydroxy-3-dodecylphenyl) ketone, bis (4-hydroxy-3,5-dimethylphenyl) ketone, bis (4-hydroxy-3,5-diethylphenyl) ketone, bis (4-hydroxy-3, -Ethyl-5-methyl) ketone, bis (4-hydroxy-3,5-dipropylphenyl) ketone, bis (4-hydroxy-3,5-dibutylphenyl) ketone, bis (4-hydroxy-3,5- Dipentylphenyl) ketone, bis (4-hydroxy-3,5-dihexylphenyl) ketone, bis (4-hydroxy-3,5-diheptylphenyl) ketone, bis (4-hydroxy-3,5-dioctylphenyl) ketone Bis (4-hydroxy-3,5-dinonylphenyl) ketone, bis (4-hydroxy-3,5-didecylphenyl) Ketone, bis (4-hydroxy-3,5-diundecylphenyl) ketone, bis (4-hydroxy-3,5-didodecylphenyl) ketone, bis (4-hydroxy-3-vinylphenyl) ketone, bis (4 Alkyl or alkenyl substituents such as -hydroxy-3,5-divinylphenyl) ketone, bis (4-hydroxy-3-allylphenyl) ketone, bis (4-hydroxy-3,5-diallylphenyl) ketone;
Bis (4-hydroxy-3-methoxyphenyl) ketone, bis (4-hydroxy-3-ethoxyphenyl) ketone, bis (4-hydroxy-3-propoxyphenyl) ketone, bis (4-hydroxy-3-butoxyphenyl) Ketone, bis (4-hydroxy-3-pentyloxyphenyl) ketone, bis (4-hydroxy-3-hexyloxyphenyl) ketone, bis (4-hydroxy-3-heptyloxyphenyl) ketone, bis (4-hydroxy) -3-octyloxyphenyl) ketone, bis (4-hydroxy-3-nonyloxyphenyl) ketone, bis (4-hydroxy-3-decyloxyphenyl) ketone, bis (4-hydroxy-3-undecyloxyphenyl) Ketone, bis (4-hydroxy-3-dodecyloxyphenyl) Bis (4-hydroxy-3,5-dimethoxyphenyl) ketone, bis (4-hydroxy-3,5-diethoxyphenyl) ketone, bis (4-hydroxy-3,5-dipropoxyphenyl) ketone, bis (4-hydroxy-3,5-dibutoxyphenyl) ketone, bis (4-hydroxy-3,5-dipentyloxysiphenyl) ketone, bis (4-hydroxy-3,5-dihexyloxyphenyl) ketone, bis ( 4-hydroxy-3,5-diheptyloxyphenyl) ketone, bis (4-hydroxy-3,5-dioctyloxyphenyl) ketone, bis (4-hydroxy-3,5-dinonyloxyphenyl) ketone, bis ( 4-hydroxy-3,5-didecyloxyphenyl) ketone, bis (4-hydroxy-3,5-diundecyl) Kishifeniru) ketone, bis (4-hydroxy-3,5-di-dodecyloxy-phenyl) ketone, alkoxy substituted compounds and the like;
Bis (4-hydroxy-3-cyclobutylphenyl) ketone, bis (4-hydroxy-3-cyclopentylphenyl) ketone, bis (4-hydroxy-3-cyclohexylphenyl) ketone, bis (4-hydroxy-3-cycloheptyl) Phenyl) ketone, bis (4-hydroxy-3-cyclooctylphenyl) ketone, bis (4-hydroxy-3-cyclononylphenyl) ketone, bis (4-hydroxy-3-decabitronaphtylphenyl) ketone, bis (4 -Hydroxy-3,5-dicyclobutylphenyl) ketone, bis (4-hydroxy-3,5-dicyclopentylphenyl) ketone, bis (4-hydroxy-3,5-dicyclohexylphenyl) ketone, bis (4-bitroxy) -3-cyclohexyl-5-methylphenyl) ketone, (4-hydroxy-3,5-dicycloheptylphenyl) ketone, bis (4-hydroxy-3,5-dicyclooctylphenyl) ketone, bis (4-hydroxy-3,5-dicyclononylphenyl) ketone , Cycloalkyl-substituted products such as bis (4-hydroxy-3,5-didecavitronaphtylphenyl) ketone;
Bis (4-hydroxy-3-phenylphenyl) ketone, bis (4-hydroxy-3,5-diphenylphenyl) ketone, bis (4-hydroxy-3-naphthylphenyl) ketone, bis (4-hydroxy-3,5 -Dinaphthylphenyl) ketone, bis (4-hydroxy-3-cyanophenyl) ketone, bis (4-hydroxy-3-nitrophenyl) ketone, bis (4-hydroxy-3-carboxyphenyl) ketone, bis (4- Hydroxy-3-halogenophenyl) ketone, bis (4-hydroxy-3,5-dicyanophenyl) ketone, bis (4-hydroxy-3,5-dinitrophenyl) ketone, bis (4-hydroxy-3,5-di) Carboxyphenyl) ketone, bis (4-hydroxy-3,5-dihalogenophenyl) ketone, and the like. That.

  Examples of esterification methods include a method of directly dehydrating ester from a carboxyl group and bisphenol compound in trimellitic anhydride, and a method of reacting a carboxyl group and a diacetate compound of bisphenol compound at high temperature to deacetate and esterify. A method, a method of dehydrating and condensing using a dehydrating reagent such as dicyclohexylcarbodiimide, a method of converting a carboxyl group into an acid halide, and reacting this with a bisphenol compound in the presence of a deoxidizing agent (base), tosyl chloride / N, Examples thereof include a method of activating and esterifying a carboxylic acid using an N-dimethylformamide / pyridine mixture. Among the above methods, trimellitic anhydride acid halide, that is, trimellitic anhydride chloride, is available at low cost, and esterification using an acid halide is preferable.

  Regarding the method using an acid halide, the reaction conditions will be described more specifically, but the present invention is not limited to these conditions. First, trimellitic anhydride chloride is dissolved in a solvent. A solution obtained by dissolving 0.5 mol and a suitable amount of a deoxidizing agent such as pyridine in the same solvent with respect to 1 mol of trimellitic anhydride chloride is slowly dropped into this solution with a dropping funnel. Under the present circumstances, reaction temperature is -10-50 degreeC normally, Preferably it is 0-30 degreeC. If the reaction temperature is higher than 50 ° C., some side reactions occur, which may reduce the yield, which is not preferable. The reaction time is exemplified by 2 to 48 hours.

  The solvent for the esterification reaction is not particularly limited, but tetrahydrofuran, 1,4-dioxane, picoline, pyridine, acetone, chloroform, toluene, xylene, dichloromethane, chloroform, 1,2-dichloroethane, N-methyl-2- Pyrrolidone, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, hexamethylphosphoramide, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, 1, Aprotic solvents such as 2-dimethoxyethane-bis (2-methoxyethyl) ether, phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, p-chlorophenol, etc. Protic dissolution of And the like. These solvents may be used alone or in combination of two or more. The amount of the solvent used is not particularly limited, but is usually in the range of 5 to 50% by weight of the solute, but is preferably in the range of 10 to 40% by weight from the viewpoint of side reaction control and precipitation filtration step. .

  The deoxidizer used in the reaction is not particularly limited, and examples thereof include organic tertiary amines such as pyridine, triethylamine and N, N-dimethylaniline, and inorganic bases such as potassium carbonate and sodium hydroxide. For example, when pyridine is used as a deoxidizing agent, pyridine hydrochloride is by-produced by the reaction, but when tetrahydrofuran is used as a solvent, pyridine hydrochloride hardly dissolves in the solvent, so the reaction solution after completion of the reaction is filtered. This is because pyridine hydrochloride can be almost completely separated. Illustrated as a preferred method.

  After completion of the reaction, the crude product can be obtained by removing the solvent from the reaction mother liquor as it is or from the filtrate obtained by filtering the hydrochloride from the reaction mother liquor under normal pressure or reduced pressure. Purification is preferably performed in order to separate and remove impurities (for example, chlorine component) in the crude product. The purification method is not particularly limited.For example, the crude product is redissolved in chloroform or ethyl acetate, and the organic layer is washed with water using a separatory funnel, the crude product is dispersed in water, Examples of the method include washing with stirring. During the water washing operation, the ester group-containing tetracarboxylic dianhydride is partially hydrolyzed to change to carboxylic acid, but is vacuum-dried at 80 to 250 ° C, preferably 120 to 200 ° C. The partially hydrolyzed product can be easily cyclized and returned to the acid dianhydride. Anhydrous acid can also be obtained by treating with an acid anhydride of an organic acid. Examples of the acid anhydride of the organic acid that can be used include acetic anhydride, propionic anhydride, maleic anhydride, phthalic anhydride, etc., but a mixed solvent containing acetic anhydride or acetic anhydride in terms of availability and drying. Are preferably used.

  The ester group-containing tetracarboxylic dianhydride after washing with water may be dried as it is. However, if the ester group-containing tetracarboxylic dianhydride is recrystallized with a mixed solvent containing acetic anhydride or acetic anhydride, the purity becomes higher. Can be obtained. During the recrystallization operation, since the ester group-containing tetracarboxylic dianhydride obtained when the recrystallization solution is heated to 120 ° C. or higher tends to be colored, it is preferable to perform the recrystallization operation at 110 ° C. or lower throughout. .

［式中、Ｒ^９、Ｒ^１０、Ｒ^１１及びＲ^１２は、同一又は異なって、水素原子、炭素数１〜１２の直鎖状若しくは分岐鎖状のアルキル基、炭素数２〜１２の直鎖状若しくは分岐鎖状のアルケニル基、又は炭素数６〜１２のシクロアルキル基を表す。Ｘは、一般式（１）におけるものと同義である。］
で表されるエステル基含有テトラカルボン酸二無水物が好ましく、Ｒ^９、Ｒ^１０、Ｒ^１１及びＲ^１２が、同一又は異なって炭素数１〜４の直鎖状若しくは分岐鎖状のアルキル基、又はシクロヘキシル基で表されるものがより好ましく、特に、メチル基又はエチル基で表されるものが好ましい。 Among the ester group-containing tetracarboxylic dianhydrides, general formula (6)

[Wherein, R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are the same or different and each represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear chain having 2 to 12 carbon atoms. Or a branched alkenyl group or a cycloalkyl group having 6 to 12 carbon atoms. X has the same meaning as in general formula (1). ]
An ester group-containing tetracarboxylic dianhydride represented by the following formula is preferred, and R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are the same or different and are linear or branched alkyl groups having 1 to 4 carbon atoms, Alternatively, those represented by a cyclohexyl group are more preferred, and those represented by a methyl group or an ethyl group are particularly preferred.

In addition, from the viewpoint of solvent solubility of the resulting polyimide, it is preferable that X in the general formula (1) is an ether group or a sulfonyl group, and a sulfonyl group is particularly preferable. Specific examples of such preferable ester group-containing tetracarboxylic dianhydrides include compounds represented by the following formulas (7) to (10).

  The ester group-containing tetracarboxylic dianhydride can be used alone or in admixture of two or more for the polymerization reaction of the polyimide precursor.

Furthermore, a part of the ester group-containing tetracarboxylic dianhydride of the present invention can be subjected to a polymerization reaction in place of other tetracarboxylic dianhydrides known in this field. Such tetracarboxylic dianhydrides include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride,
3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfonetetra Carboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropanoic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) propanoic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride aromatic tetracarboxylic dianhydride;
Bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5- (dioxotetrahydrofuryl-3-methyl-3-cyclohexene-1,2-dicarboxylic acid Acid anhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -tetralin-1,2-dicarboxylic anhydride, tetrahydrofuran-2,3,4,5-tetracarboxylic dianhydride, bicyclohexyl -3,3 ', 4,4'-tetracarboxylic dianhydride, 3c-carboxymethylcyclopentane-1r, 2c, 4c-tricarboxylic acid-1,4: 2,3-dianhydride, 1,2, Aliphatic compounds such as 4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride Examples thereof include alicyclic tetracarboxylic dianhydrides, which can be used alone or in a mixture of two or more for the polymerization reaction.These aromatic tetracarboxylic dianhydrides, aliphatic Alternatively, when using an alicyclic tetracarboxylic dianhydride, the amount used is 50 mol% or less, preferably 30 mol% or less, more preferably 10 mol% or less, especially in all tetracarboxylic dianhydrides. 5 mol% or less is desirable.

  Examples of the alicyclic diamine include linear or branched alkyl groups having 1 to 12 carbon atoms, linear or branched alkoxy groups having 1 to 12 carbon atoms, and cycloalkyl having 4 to 12 carbon atoms. C6-C24 alicyclic diamine which may have one or more substituents chosen from the group which consists of group, a nitrile group, a nitro group, a carboxyl group, an amide group, and a halogen atom is mentioned. In the claims and specification of the present application, the alicyclic diamine means a compound having at least one alicyclic structure in the structure, and the alicyclic structure includes a cyclo ring, a bicyclo ring, Any of spiro rings may be used.

  Specific examples of the alicyclic diamine include 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, bis (4-aminocyclohexyl) methane, and bis (4-amino-2-methyl). Cyclohexyl) methane, bis (4-amino-2-ethylcyclohexyl) methane, bis (4-amino-3,5-dimethylcyclohexyl) methane, bis (4-amino-3,5-diethylcyclohexyl) methane, bis (4 -Amino-3-ethyl-5-methylcyclohexyl) methane, bis (4-amino-3,5-dicyclohexylcyclohexyl) methane, 1,1-bis (4-aminocyclohexyl) ethane, 1,1-bis (4- Amino-2-methylcyclohexyl) ethane, 1,1-bis (4-amino-2-ethyl) Chloro) ethane, 1,1-bis (4-amino-3,5-dimethylcyclohexyl) ethane, 1,1-bis (4-amino-3,5-diethylcyclohexyl) ethane, 1,1-bis (4- Amino-3ethyl-5-methylcyclohexyl) ethane, 1,1-bis (4-amino-3,5-dicyclohexylcyclohexyl) ethane, 2,2-bis (4-aminocyclohexyl) propane, 2,2-bis ( 4-amino-3-methylcyclohexyl) propane, 2,2-bis (4-amino-3-ethylcyclohexyl) propane, 2,2-bis (4-amino-3,5-dimethylcyclohexyl) propane, 2,2 -Bis (4-amino-3,5-diethylcyclohexyl) proban, 2,2-bis (4-amino-3ethyl-5-methylcyclohexyl) L) Proban, 2,2-bis (4-amino-3,5-dicyclohexylcyclohexyl) proban, 2,2-bis (4-aminocyclohexyl) butane, 2,2-bis (4-amino-3-methylcyclohexyl) ) Butane, 2,2-bis (4-amino-3-ethylcyclohexyl) butane, 2,2-bis (4-amino-3,5-dimethylcyclohexyl) butane, 2,2-bis (4-amino-3) , 5-diethylcyclohexyl) butane, 2,2-bis (4-amino-3ethyl-5-methylcyclohexyl) butane, 2,2-bis (4-amino-3,5-dicyclohexylcyclohexyl) butane, 2,2 -Bis (4-aminocyclohexyl) hexafluoropropane, 2,2-bis (4-amino-3-methylcyclohexyl) hexafluoropropane Lopan, 2,2-bis (4-amino-3-ethylcyclohexyl) hexafluoropropane, 2,2-bis (4-amino-3,5-dimethylcyclohexyl) hexafluoropropane, 2,2-bis (4- Amino-3,5-diethylcyclohexyl) hexafluoropropane, 2,2-bis (4-amino-3ethyl-5-methylcyclohexyl) hexafluoropropane, 2,2-bis (4-amino-3,5-dicyclohexyl) (Cyclohexyl) hexafluoropropane, 1,1-bis (4-aminocyclohexyl) cyclohexane, 1,1-bis (4-amino-2-methylcyclohexyl) cyclohexane, 1,1-bis (4-amino-2-ethylcyclohexyl) ) Cyclohexane, 1,1-bis (4-amino-3,5-dimethylcyclohexane) Syl) cyclohexane, 1,1-bis (4-amino-3,5-diethylcyclohexyl) cyclohexane, 1,1-bis (4-amino-3ethyl-5-methylcyclohexyl) cyclohexane, 1,1-bis (4 -Amino-3,5-dicyclohexylcyclohexyl) cyclohexane, 1,2-bis (aminomethyl) cyclohexane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 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, isophoronediamine, 1,3-diaminoadamantane and the like.

［式中、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、Ａ^１、Ａ^２及びｍは、ぞれぞれ一般式（２）におけるものと同義である。］
で表されるシクロヘキサン骨格を有する脂環族ジアミンが好ましく、特に、２つのアミノ基が直接シクロヘキサン環に直接結合している脂環族ジアミンが好ましい。かかる好ましい脂環族ジアミンとしては具体的には、１，４−ビス（アミノメチル）シクロヘキサン、１，４−シクロヘキサンジアミン、ビス（４−アミノシクロヘキシル）メタン、ビス（４−アミノ−３−メチルシクロヘキシル）メタン、ビス（４−アミノ−３−エチルシクロヘキシル）メタン、ビス（４−アミノ−３，５−ジメチルシクロヘキシル）メタン、ビス（４−アミノ−３，５−ジエチルシクロヘキシル）メタン、ビス（４−アミノ−３エチル−５−メチルシクロヘキシル）メタン、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−３−メチルシクロヘキシル）プロパン、２，２−ビス（４−アミノ−３−エチルシクロヘキシル）プロパン、２，２−ビス（４−アミノ−３，５−ジメチルシクロヘキシル）プロパン、２，２−ビス（４−アミノ−３，５−ジエチルシクロヘキシル）プロパン、２，２−ビス（４−アミノ−３エチル−５−メチルシクロヘキシル）プロパン、が例示され、特に、１，４−シクロヘキサンジアミン、ビス（４−アミノシクロヘキシル）メタン、ビス（４−アミノ−３−メチルシクロヘキシル）メタン、ビス（４−アミノ−３−エチルシクロヘキシル）メタン、ビス（４−アミノ−３，５−ジメチルシクロヘキシル）メタン、ビス（４−アミノ−３，５−ジエチルシクロヘキシル）メタン、ビス（４−アミノ−３エチル−５−メチルシクロヘキシル）メタン、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−３−メチルシクロヘキシル）プロパン、２，２−ビス（４−アミノ−３−エチルシクロヘキシル）プロパン、２，２−ビス（４−アミノ−３，５−ジメチルシクロヘキシル）プロパン、２，２−ビス（４−アミノ−３，５−ジエチルシクロヘキシル）プロパン、２，２−ビス（４−アミノ−３エチル−５−メチルシクロヘキシル）プロパンが好ましい。 Among these alicyclic diamines, general formula (11) from the viewpoint of excellent heat resistance and transparency of the resulting polyimide.

[Wherein R ⁵ , R ⁶ , R ⁷ , R ⁸ , A ¹ , A ² and m have the same meanings as in general formula (2), respectively. ]
The cycloaliphatic diamine which has the cyclohexane skeleton represented by these is preferable, and especially the alicyclic diamine in which two amino groups are directly couple | bonded with the cyclohexane ring is preferable. Specific examples of such preferable alicyclic diamines include 1,4-bis (aminomethyl) cyclohexane, 1,4-cyclohexanediamine, bis (4-aminocyclohexyl) methane, and bis (4-amino-3-methylcyclohexyl). ) Methane, bis (4-amino-3-ethylcyclohexyl) methane, bis (4-amino-3,5-dimethylcyclohexyl) methane, bis (4-amino-3,5-diethylcyclohexyl) methane, bis (4- Amino-3ethyl-5-methylcyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, 2,2-bis (4-amino-3-methylcyclohexyl) propane, 2,2-bis (4- Amino-3-ethylcyclohexyl) propane, 2,2-bis (4-amino-3,5-dimethylcycle) Hexyl) propane, 2,2-bis (4-amino-3,5-diethylcyclohexyl) propane, 2,2-bis (4-amino-3ethyl-5-methylcyclohexyl) propane, and particularly 1 , 4-cyclohexanediamine, bis (4-aminocyclohexyl) methane, bis (4-amino-3-methylcyclohexyl) methane, bis (4-amino-3-ethylcyclohexyl) methane, bis (4-amino-3,5) -Dimethylcyclohexyl) methane, bis (4-amino-3,5-diethylcyclohexyl) methane, bis (4-amino-3ethyl-5-methylcyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, 2,2-bis (4-amino-3-methylcyclohexyl) propane, 2,2-bis (4-a Nor-3-ethylcyclohexyl) propane, 2,2-bis (4-amino-3,5-dimethylcyclohexyl) propane, 2,2-bis (4-amino-3,5-diethylcyclohexyl) propane, 2,2 -Bis (4-amino-3ethyl-5-methylcyclohexyl) propane is preferred.

Among the alicyclic diamines having a cyclohexane skeleton represented by the general formula (11), those in which amino groups bonded to the cyclohexane ring are in a trans configuration are preferable from the viewpoint of excellent heat resistance of the obtained polyimide. That is, in the general formula (11), when m is 1, an alicyclic diamine in which the configuration of A ¹ and A ² bonded to the cyclohexane ring is a trans configuration is preferable, and when m is 2, Preference is given to alicyclic diamines in which the configuration of A ¹ and A ² is in the trans configuration and / or the configuration of the two A ^{2 in} the trans configuration. Incidentally, in all of the repeating structural units represented by the general formula (1) or the general formula (3), the trans configuration is desirable, but 50 mol% or more, preferably 80 mol% or more of all repeating structural units. In particular, it is desirable that 95 mol% or more is an alicyclic diamine having a trans configuration. In other words, when m is 2, an alicyclic diamine in which the configuration of A ¹ and A ² is a cis configuration and the configuration of two A ² is a cis configuration is preferably 50 mol% or less, preferably Is preferably 20 mol% or less, and particularly preferably 5 mol% or less.

  Furthermore, if necessary, a part of the alicyclic diamine can be used in the polymerization reaction in place of other diamines known in this field. Specific examples of such diamines include 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8. -Aliphatic diamines such as octamethylenediamine and 1,9-nonamethylenediamine; p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, 2 , 4-diaminodurene, 4,4′-diaminodiphenylmethane, 4,4′-methylenebis (2-methylaniline), 4,4′-methylenebis (2-ethylaniline), 4,4′-methylenebis (2,6 -Dimethylaniline), 4,4'-methylenebis (2,6-diethylaniline), 4,4'-diamino Phenyl ketone, 3,4'-diaminodiphenyl ketone, 3,3'-diaminodiphenyl ketone, 2,4'-diaminodiphenyl ketone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4, 4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzanilide, benzidine, 3,3'-dihydroxybenzidine, 3,3'-dimethoxybenzidine, o-tolidine, m-tolidine, 2 , 2′-bis (trifluoromethyl) benzidine, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene 4,4′-bis (4-aminophenoxy) biphenyl, bis (4- (3-aminophen Xyl) phenyl) sulfone, bis (4- (4-aminophenoxy) phenyl) sulfone, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-amino) And aromatic diamines such as phenoxy) phenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, and p-terphenylenediamine.

  These diamines can be used alone or in admixture of two or more. When these aliphatic diamines and aromatic diamines are used, 20 mol% or less, preferably 10 mol% or less, particularly 5 mol% or less of the total diamine component is recommended.

  In addition, in this invention, in the range which does not impair the effect of this invention, end cap agents, such as monofunctional acid anhydride and amine, can be used together for the purpose of heat resistance, adhesive improvement, molecular weight control, etc. Specific examples of the end cap agent include phthalic anhydride, maleic anhydride, nadic anhydride, hexahydrophthalic anhydride and the like as the acid anhydride, and aniline, methylaniline, allylamine and the like as the amine. .

<Production of polyimide precursor>
There is no restriction | limiting in particular as a method of obtaining a polyimide precursor from the said ester group containing tetracarboxylic dianhydride and alicyclic diamine, It can manufacture by a conventionally well-known method. For example, alicyclic diamine is dissolved in a polar organic solvent under an inert gas atmosphere, and the ester group-containing tetracarboxylic dianhydride is gradually added to this solution at room temperature while stirring, and stirred for 1 to 72 hours. Can be obtained. In the present invention, the alicyclic diamine and the ester group-containing tetracarboxylic dianhydride do not form an amine salt that is hardly soluble in the solvent, and the polymerization reaction proceeds easily. The presence or absence of amine salt formation can be determined by the presence or absence of turbidity in the polymerization solution. Those in which the polymerization solution is not turbid are substantially free of amine salts.

  The usage-amount of the ester group containing tetracarboxylic dianhydride with respect to alicyclic diamine is 0.95-1.05 in molar ratio, Preferably it is 0.98-1.02. The monomer concentration is usually 5 to 30% by weight, preferably 10 to 20% by weight.

  Examples of polar organic solvents include N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, dimethylsulfoxide, γ-butyrolactone, 1 , 3-dimethyl-2-imidazolidinone, 1,2-dimethoxyethane-bis (2-methoxyethyl) ketone, terahydrofuran, 1,4-dioxane, picoline, pyridine, acetone, chloroform, toluene, xylene, etc. Solvents such as aprotic solvents such as aprotic solvents, phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, p-chlorophenol and the like.

  In the polymerization reaction of the polyimide precursor, the molecular weight of the imide group-containing polyimide precursor can be appropriately adjusted by selecting reaction conditions such as reaction temperature, reaction time, and raw material usage ratio. After the polymerization reaction as described above, the obtained slurry product is stirred and washed in a solvent such as methanol, ethanol, isopropyl alcohol, water, etc., and then dried under reduced pressure, whereby the above general formula (1) is obtained. A polyimide precursor is obtained. Usually, the reaction solution after completion of the polymerization reaction or a solution diluted with the same solvent as used in the above reaction can be used as the polyimide precursor varnish as necessary.

  It is also possible to carry out a polymerization reaction using a polymer dissolution accelerator often added during polymerization of the polyimide precursor, that is, metal salts such as lithium bromide and lithium chloride, but these metal salts are contained in the polyimide. If even a trace amount remains, when used as an electronic device material, the reliability is remarkably lowered, so it is not recommended to use it. In the present invention, a high molecular weight polyimide precursor can be obtained without using these.

  The polyimide precursor thus obtained is a high molecular weight polyimide precursor which does not substantially contain an alicyclic amine salt or a metal salt, and its molecular weight is usually 0 in a N, N-dimethylacetamide solvent. It is recommended that the intrinsic viscosity measured with an Ostwald viscometer under conditions of 0.5 g / dL and 30 ° C. is 0.4 dL / g or more, preferably 0.9 dL / g or more. The upper limit of the intrinsic viscosity is not particularly limited, but is usually 4.0 dL / g or less.

<Polyimide precursor varnish>
The polymerization reaction solution thus obtained is a polyimide precursor solution obtained by dissolving a polyimide precursor having the structural unit represented by the general formula (1) in the organic solvent used in the polymerization reaction. It is recommended that the concentration of is dissolved in the range of usually 1 to 50% by weight, preferably 5 to 30% by weight, particularly 10 to 20% by weight. The polyimide precursor solution can be used as it is as a polyimide resin precursor varnish, and the organic solvent used in the polymerization reaction is a low boiling point solvent (for example, aromatic hydrocarbons such as toluene, xylene, solvent naphtha, cyclohexane, etc. , Cycloaliphatic hydrocarbons such as methylcyclohexane and dimethylcyclohexane, ethers such as propylene glycol monomethyl ether and propylene glycol dimethyl ether, or ketones such as methyl ethyl ketone and methyl isobutyl ketone), or the polyimide precursor solution Or by adding a poor solvent (for example, lower alcohols such as methanol and isopropyl alcohol, acetic acid esters such as ethyl acetate and butyl acetate) and the like to isolate the polyimide precursor of the present invention, Desired Dissolved in an organic solvent can be a polyimide precursor varnish, the concentration of the polyimide at that time, it is recommended that the same concentration range as the polyimide precursor solution.

  Furthermore, the polyimide precursor varnish of the present invention contains an oxidation stabilizer, a terminal blocking agent, a filler, a silane coupling agent, a crosslinking agent, a photosensitizer, a photopolymerization initiator, a sensitizer, and the like as necessary. be able to.

<Polyimide and polyimide varnish>
The polyimide represented by the general formula (3) can be produced from the polyimide precursor varnish according to a known method. For example, as a method of imidation reaction, (1) a method in which the polyimide precursor varnish is heated to 100 to 250 ° C. in the presence of a small amount of azeotropic solvent, and the generated water is distilled out of the system by azeotropic distillation, (2) Examples include a method using a compound having a dehydrating action such as acetic anhydride for the polyimide precursor varnish.

  Examples of the azeotropic solvent include aromatic hydrocarbons such as toluene, xylene and solvent naphtha, and alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and dimethylcyclohexane. These may be used alone or in combination of two or more. Can be used. When an azeotropic solvent is used, the amount used is recommended to be 1 to 30% by weight, preferably 5 to 10% by weight, based on the total organic solvent.

  The reaction time is usually preferably 0.5 to 24 hours.

  The imidization reaction solution thus obtained is a polyimide resin solution obtained by dissolving a polyimide having a structural unit represented by the general formula (3) in an organic solvent used for the imidation reaction. 1-100 weight part of this imide is melt | dissolving with respect to 100 weight part of solvents. From the viewpoint of handleability of the polyimide resin solution, the imide is preferably 5 to 90 parts by weight, more preferably 20 to 80 parts by weight, and particularly preferably 30 to 75 parts by weight with respect to 100 parts by weight of the organic solvent. It is recommended that it be dissolved in The polyimide resin solution can be used as it is as a polyimide resin varnish, and the organic solvent used in the imidization reaction is a low-boiling solvent (for example, aromatic hydrocarbons such as toluene, xylene, solvent naphtha, cyclohexane, methyl, etc. Or cycloaliphatic hydrocarbons such as dimethylcyclohexane, ethers such as propylene glycol monomethyl ether and propylene glycol dimethyl ether, or ketones such as methyl ethyl ketone and methyl isobutyl ketone), or drying the polyimide resin solution by heating Alternatively, the polyimide of the present invention can be isolated by adding a poor solvent (for example, lower alcohols such as methanol and isopropyl alcohol, and acetic acid esters such as ethyl acetate and butyl acetate). The isolated polyimide can be made into a polyimide powder by drying, or it can be dissolved in another desired organic solvent to form a polyimide varnish, and the polyimide concentration at that time is determined by the polyimide resin solution. The same concentration range is recommended.

  Furthermore, the polyimide varnish of the present invention may contain an oxidation stabilizer, a terminal blocking agent, a filler, a silane coupling agent, a crosslinking agent, a photosensitizer, a photopolymerization initiator, a sensitizer, and the like as necessary. it can.

  The polyimide of the present invention preferably has a glass transition temperature of 200 ° C. or higher, more preferably 230 ° C. or higher. The light transmittance at a wavelength of 400 nm is preferably 60% or more, more preferably 65% or more, and birefringence is preferably 0.1 or less, more preferably 0.05 or less, In particular, 0.01 or less is recommended. The elongation at break is preferably 5% or more, particularly preferably 7% or more.

  The water absorption is preferably 2% by weight or less, particularly preferably 1% by weight or less. The elastic modulus is preferably 1 GPa or more, particularly 1.5 GPa or more. The thermal expansion coefficient is preferably 80 ppm / K or less, particularly preferably 30 ppm / K. The cutoff wavelength is preferably shorter than 360 nm, particularly shorter than 350 nm.

<Polyimide molded product>
The polyimide precursor of the present invention can be obtained by drying and curing the polyimide precursor varnish and the polyimide varnish (hereinafter referred to as “the present varnish” together) according to a conventionally known method. Moreover, also when isolated as a polyimide powder, the molded object of this invention can be obtained by shape | molding using conventionally well-known shaping | molding methods, such as compression molding, injection molding, and extrusion molding. From the viewpoint of easy handling, it is preferable to obtain a molded body from the varnish.

  For example, the present varnish is directly applied to the surface of the adherend by a known method, or the adherend is dipped in the present varnish of the present invention, and the resulting coating film is dried and cured to obtain a polyimide molded body. It can be. In this case, the resulting polyimide form is usually in the form of an electrically insulating layer or film. Although the thickness of this layer or film depends on the purpose of use, it is generally 0.1 to 500 μm, preferably 3 to 200 μm.

  Moreover, after apply | coating this varnish on support bodies, such as resin films, such as a glass substrate or PET, and drying and hardening the obtained coating film, the polyimide molded body obtained is peeled from a support body, and is sheet-like. Or a film-like molded object can also be obtained. It should be noted that the peeling from the support may not be performed after the drying and curing are completed, and after drying and curing until the self-supporting property is obtained, the drying and curing are performed again after peeling from the support. You may go. This method for producing a molded article is a preferred production method when the imide molded article of the present invention is used as a plastic substrate.

  Here, “drying and curing” means volatilization of the organic solvent from the varnish, and in the case of the polyimide precursor varnish, volatilization of the organic solvent and imidization reaction. Are not strictly distinguished. The drying and curing conditions vary depending on the type of base material and the method of use, but typically include conditions of 50 to 400 ° C. (preferably 100 to 350 ° C.) and 10 to 400 minutes (preferably 60 to 200 minutes). . In addition, it is desirable to perform heating while raising the temperature stepwise. The drying and curing are preferably performed in a vacuum or in an inert gas atmosphere such as nitrogen, and may be performed using a dehydrating reagent such as acetic anhydride.

<Plastic substrate>
The plastic substrate of the present invention is a glass substitute substrate using the above polyimide molded body, and may consist of a polyimide molded body alone, or on the surface of the polyimide molded body, such as a hard coat layer, a gas barrier layer, and ITO. It may be a plastic substrate composed of a plurality of layers on which transparent electrodes are formed. Applications of the plastic substrate include a wide range, for example, liquid crystal display substrates, organic electroluminescence (organic EL) display substrates, plastic substrates for display elements such as electronic paper substrates, solar cell substrates, touch panels. Films and the like are exemplified. Especially, it is suitable for the plastic substrate for display elements, and can be used suitably especially for the plastic substrate for flexible film liquid crystal displays. Therefore, the present invention also provides a display element comprising the plastic substrate of the present invention. Examples of the display element include a liquid crystal display, an organic EL display, and electronic paper.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, it is not limited to these Examples. The physical property values in the following examples were measured by the following methods.
<Infrared absorption spectrum: IR>
Using a Fourier transform infrared spectrophotometer (FT-IR5300 manufactured by JASCO Corporation), the infrared absorption spectra of the polyimide precursor and the polyimide thin film were measured by a transmission method. In order to confirm the molecular structure of the synthesized ester group-containing tetracarboxylic dianhydride, an infrared absorption spectrum was measured by the KBr method.

<Intrinsic viscosity>
A 0.5% by weight polyimide precursor solution (solvent: N, N-dimethylacetamide) was measured at 30 ° C. using an Ostwald viscometer.

<Glass transition temperature: Tg>
The glass transition temperature of the polyimide film was determined from the loss peak at a frequency of 0.1 Hz and a heating rate of 5 ° C./min by dynamic viscoelasticity measurement using a thermomechanical analyzer (TMA4000) manufactured by Bruker Ax.

<Linear thermal expansion coefficient: CTE>
The range of 100 to 200 ° C. from the elongation of the test piece at a load of 0.5 g / film thickness of 1 μm and a heating rate of 5 ° C./min by thermomechanical analysis using a Bruker Ax thermomechanical analyzer (TMA4000). The linear thermal expansion coefficient of the polyimide film was determined as the average value at.

<5% weight loss temperature: Td ⁵ >
Using a Bruker Ax thermogravimetric analyzer (TG-DTA2000), the initial weight of the polyimide film decreased by 5% in the temperature rising process from room temperature to 400 ° C. at a temperature rising rate of 10 ° C./min in nitrogen. The temperature of the hour was measured. Higher values indicate higher thermal stability.

<Cutoff wavelength>
Using a UV-visible spectrophotometer (V-520) manufactured by JASCO Corporation, the visible / ultraviolet transmittance from 200 nm to 900 nm was measured. The wavelength (cutoff wavelength) at which the transmittance was 0.5% or less was used as an index of transparency. The shorter the cutoff wavelength, the better the transparency of the polyimide film.

<Light transmittance>
The light transmittance at 400 nm was measured using an ultraviolet-visible spectrophotometer (V-520) manufactured by JASCO Corporation. Higher light transmittance means that the transparency of the polyimide film is better.

<Birefringence>
Using an Abbe refractometer (Abbe 4T) manufactured by Atago Co., Ltd., the refractive index _{in the} direction parallel to the polyimide film (n _in ) and perpendicular to the direction (n _out ) is measured with an Abbe refractometer (using a sodium lamp, wavelength 589 nm) The birefringence (Δn = n _in −n _out ) was determined from the difference between these refractive indexes.

<Water absorption rate>
A polyimide film (film thickness: 20 to 30 μm) vacuum-dried at 50 ° C. for 24 hours was immersed in water at 25 ° C. for 24 hours, and then excess water was wiped off, and the water absorption (%) was determined from the increase in mass.

<Elastic modulus, elongation at break>
Using a tensile tester (Tensilon UTM-2) manufactured by Toyo Baldwin Co., Ltd., a tensile test (stretching speed: 8 mm / min) was performed on a polyimide film specimen (3 mm × 30 mm), and the initial slope of the stress-strain curve From the elongation, the elongation at break (%) was determined from the elongation at the time when the membrane was broken. Higher elongation at break means higher film toughness.

<Synthesis Example 1> Synthesis of ester group-containing tetracarboxylic dianhydride 50 mmol of trimellitic anhydride chloride is dissolved in 27 mL of tetrahydrofuran and sealed. To this solution, 25 mmol of 4,4′-dihydroxydiphenylsulfone and 6 mL of pyridine dissolved in 14 mL of tetrahydrofuran were slowly added dropwise at room temperature using a syringe, and a white precipitate was formed. After completion of the dropwise addition, the reaction mixture was stirred at room temperature for 24 hours. After the solvent of the reaction solution was distilled off with an evaporator, water was added to the flask and washed to remove pyridine hydrochloride. It was vacuum dried at 180 ° C. for 24 hours to obtain a white crude product. Furthermore, recrystallized with acetic anhydride / acetic acid (volume ratio 7/3), washed with benzene, and finally dried under vacuum at 180 ° C. for 24 hours, and abbreviated as ester group-containing tetracarboxylic dianhydride (hereinafter abbreviated as “TAPS”). .) In addition, the characteristic absorption of the phenyl ester group and the acid anhydride group was confirmed from the IR of the product, and it was confirmed to be the target product.

<Synthesis Example 2> Synthesis of ester group-containing tetracarboxylic dianhydride 50 mmol of trimellitic anhydride chloride was dissolved in 47 mL of tetrahydrofuran. To this solution, 25 mmol of 4,4′-dihydroxydiphenyl ketone and 6 mL of pyridine dissolved in 23 mL of tetrahydrofuran were slowly added dropwise at room temperature using a syringe. A white precipitate formed following the dropwise addition. After completion of the dropwise addition, the reaction mixture was stirred at room temperature for 24 hours. The reaction solution was filtered to remove the white precipitate of pyridine hydrochloride in advance, and then the solvent was distilled off with an evaporator, followed by vacuum drying at 150 ° C. for 24 hours to obtain a yellow crude product. Next, in order to completely remove pyridine hydrochloride, solvent and pyridine, the crude product was thoroughly washed with water and vacuum-dried at 150 ° C. for 24 hours. Further, recrystallized twice with acetic anhydride / acetic acid (volume ratio 3/2), washed with benzene, and finally dried under vacuum at 150 ° C. for 24 hours to form ester group-containing tetracarboxylic dianhydride (hereinafter referred to as “TADE”). Abbreviated.) In addition, the characteristic absorption of the phenyl ester group and the acid anhydride group was confirmed from the IR of the product, and it was confirmed to be the target product.

<Synthesis Example 3>
First, 50 mmol of trimellitic anhydride chloride was dissolved in 47 mL of tetrahydrofuran. To this solution, 25 mmol of 4,4′-dihydroxybenzene and 6 mL of pyridine dissolved in 34 mL of tetrahydrofuran were slowly added dropwise at room temperature using a syringe. A white precipitate formed following the dropwise addition. After completion of the dropwise addition, the reaction mixture was stirred at room temperature for 24 hours. The reaction solution was filtered to remove pyridine hydrochloride in advance, and then the solvent was distilled off with an evaporator, followed by vacuum drying at 180 ° C. for 24 hours to obtain a white crude product. Further, recrystallized with acetic anhydride / acetic acid (volume ratio 7/3), washed with benzene, and finally dried under vacuum at 180 ° C. for 24 hours to obtain a high purity ester group-containing tetracarboxylic dianhydride (hereinafter referred to as “TAHQ”). Is abbreviated as).

<Example 1>
[Synthesis of polyimide precursor]
In a reaction vessel equipped with a stirrer, 10 mmol of bis (4-aminocyclohexyl) methane (cis-cis isomer content 8 mol%) was dissolved in 50 mL of N, N-dimethylacetamide, and this solution was obtained in Synthesis Example 1. 10 mmol of tetracarboxylic dianhydride (TAPS) was gradually added. After the addition of tetracarboxylic dianhydride, a completely uniform and transparent solution was obtained after about 30 minutes. Furthermore, it stirred at room temperature for 24 hours and obtained the transparent and viscous polyimide precursor solution. The solute concentration at this time was 14.7% by weight. This polyimide precursor solution did not precipitate or gel at all even when allowed to stand at room temperature and −20 ° C. for one month, and showed extremely high solution storage stability. The intrinsic viscosity of the polyimide precursor measured in N, N-dimethylacetamide at 30 ° C. was 0.911 dL / g, which was a high polymer.

[Evaluation of polyimide]
The polyimide precursor solution obtained by applying this polyimide precursor solution to a glass substrate and drying it at 60 ° C. for 1 hour is gradually increased on the substrate at 180 ° C., 230 ° C. and 250 ° C. for 30 minutes under reduced pressure. It was heated and heat-treated at 300 ° C. for 1 hour to obtain a transparent and tough polyimide film having a thickness of 20 μm. The completion of imidization was confirmed from the infrared absorption spectrum. In order to remove the residual strain, the film was peeled off from the substrate and then further heat treated at 210 ° C. for 1 hour. The polyimide film was not broken by a 180 ° bending test and showed flexibility. Table 1 shows the evaluation results of this polyimide film. This polyimide exhibited solubility in N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, and m-cresol. Infrared absorption spectra of the polyimide precursor and the polyimide thin film are shown in FIGS.

<Example 2>
A polyimide precursor and a polyimide film were prepared in the same manner as in Example 1 except that TADE obtained in Synthesis Example 2 was used instead of TAPS. The obtained polyimide film was not broken even by a 180 ° bending test and showed flexibility. The evaluation results of this polyimide film are shown in Table 1. The infrared absorption spectra of the polyimide precursor and the polyimide thin film are shown in FIGS.

<Example 3>
A polyimide was prepared in the same manner as in Example 1 except that trans-1,4-cyclohexanediamine was used instead of bis (4-methylcyclohexyl) methane, and TADE obtained in Synthesis Example 2 was used instead of TAPS. A precursor and a polyimide film were obtained. The obtained polyimide film showed flexibility without breaking even in a 180 ° bending test. The other evaluation results are shown in Table 1, and the infrared absorption spectra of the polyimide precursor and the polyimide film are shown in FIG. 5 and FIG.

<Comparative Example 1>
In a reaction vessel equipped with a stirrer, 10 mmol of trans-1,4-cyclohexanediamine was dissolved in 50 mL of N, N-dimethylacetamide, and 10 mmol of pyromellitic dianhydride was gradually added to this solution. However, a very strong insoluble salt was formed at the beginning of the reaction, the polymerization reaction did not proceed at all, and a polyimide precursor was not obtained.

<Comparative example 2>
A polyimide precursor was synthesized in the same manner as in Example 1 except that pyromellitic dianhydride was used instead of TAPS. However, a salt insoluble in the solvent was formed immediately after the reaction. It took several days of reaction time until the salt disappeared and a viscous polyimide precursor was obtained. The intrinsic viscosity of the obtained polyimide precursor is shown in Table 1. Further, polyimide and a polyimide film were prepared in the same manner as in Example 1. When the obtained polyimide film was subjected to a 180 ° bending test, it was broken and the toughness was insufficient. The evaluation results of other polyimide films are shown in Table 1.

<Comparative Example 3>
A polyimide precursor was synthesized in the same manner as in Example 1 except that TAHQ obtained in Synthesis Example 3 was used instead of TAPS. However, in this polymerization, a large amount of strong salt was formed, and it took 96 hours until a uniform and transparent solution was obtained after the addition of tetracarboxylic dianhydride. Furthermore, it stirred at room temperature for 24 hours and obtained the transparent and viscous polyimide precursor solution. The solute concentration at this time was 11.2% by weight. A polyimide film was prepared in the same manner as in Example 1. This polyimide precursor cast film was transparent again, but some turbidity was generated in the polyimide film because of crystallization of the polyimide. The results of evaluation using this polyimide film are shown in Table 1. When the obtained polyimide film was subjected to a 180 ° bending test, it was broken and the toughness was insufficient. Further, this polyimide did not dissolve in solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide and m-cresol.

<Comparative example 4>
A polyimide precursor was synthesized in the same manner as in Example 1 except that trans-1,4-cyclohexanediamine was used instead of bis (4-aminocyclohexyl) methane, and TAHQ was used instead of TAPS. It was. However, even in comparison with Comparative Example 3, a large amount of insoluble salt was formed, and after adding tetracarboxylic dianhydride, it took 168 hours until a uniform and transparent solution was obtained. A polyimide film was prepared in the same manner as in Example 1 using the obtained polyimide precursor solution. This polyimide precursor cast film was transparent again, but some turbidity was generated in the polyimide film because of crystallization of the polyimide. The results of evaluation using this polyimide film are shown in Table 1. Further, this polyimide did not dissolve in solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide and m-cresol.

Table 1

As is clear from Examples 1 to 3, the polyimide of the present invention provides a polyimide precursor having a high degree of polymerization despite the use of an alicyclic diamine as the diamine, and the polyimide is transparent. , High birefringence, excellent optical properties, mechanical properties such as elastic modulus and elongation at break, and heat resistance.
On the other hand, in Comparative Examples 1 and 2, a polyimide precursor cannot be obtained due to salt formation. In Comparative Examples 3 and 4, even if a polyimide precursor is obtained, polyimide is inferior in transparency and lacks toughness. .

  The polyimide of the present invention is useful as a material for a plastic substrate as a substitute for a glass substrate used in the field of electric / electronic components, such as for liquid crystal displays, for organic electroluminescence displays, for electronic paper, for solar cells, etc. It can be used for various applications such as plastic substrates for substituting glass substrates, electrical insulating films for electronic devices, optical materials, protective films for solar cell panels, and optical waveguides. In particular, since the polyimide copolymer of the present invention has high toughness, it can be applied particularly as a flexible film.

IR chart of the polyimide precursor obtained in Example 1 IR chart of the polyimide obtained in Example 1 IR chart of the polyimide precursor obtained in Example 2 IR chart of the polyimide obtained in Example 2 IR chart of the polyimide precursor obtained in Example 3 IR chart of the polyimide obtained in Example 3

Claims (19)

General formula (1)

[Wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear chain having 2 to 12 carbon atoms. Or branched alkenyl group, linear or branched alkoxy group having 1 to 12 carbon atoms, cycloalkyl group having 4 to 12 carbon atoms, nitrile group, nitro group, carboxyl group, amide group, halogen atom Or a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, a linear or branched chain having 1 to 12 carbon atoms An alicyclic group having 6 to 12 carbon atoms or 6 carbon atoms which may have one or more substituents selected from the group consisting of an alkoxy group, a nitrile group, a nitro group, a carboxyl group, an amide group and a halogen atom. Table of 12 aromatic groups . X represents an ether group, a thioether group, a carbonyl group or a sulfonyl group. Z is a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkoxy group having 1 to 12 carbon atoms, a cycloalkyl group having 4 to 12 carbon atoms, a nitrile group, A bivalent alicyclic group having 6 to 24 carbon atoms which may have one or more substituents selected from the group consisting of a nitro group, a carboxyl group, an amide group and a halogen atom. The substitution positions of the two phenoxycarbonyl groups bonded to the benzene rings at both ends are the same or different and are the m-position or p-position with respect to the carbamoyl group. ]
The polyimide precursor which has a structural unit represented by these. R ¹ , R ² , R ³ and R ⁴ are the same or different and are a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched chain having 2 to 12 carbon atoms. The polyimide precursor of Claim 1 represented by a shape-like alkenyl group or a C6-C12 cycloalkyl group.   The polyimide precursor according to claim 1, wherein X is represented by a sulfonyl group or an ether group. Z is the general formula (2)

[Wherein, R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different from each other and each represents a hydrogen atom, a methyl group or an ethyl group. A ¹ and m A ² are the same or different and each represents a direct bond or an alkylidene group having 1 to 6 carbon atoms. m represents an integer of 1 or 2. ]
The polyimide precursor in any one of Claims 1-3 represented by these. The polyimide precursor according to claim 4, wherein the configuration of A ¹ and A ² is a trans configuration, or the configuration of two A ² is a trans configuration.   The polyimide precursor in any one of Claims 1-5 which does not contain an amine salt substantially.   Intrinsic viscosity is 0.4 dL / g or more, The polyimide precursor in any one of Claims 1-6.   A polyimide precursor varnish comprising the polyimide precursor according to claim 1 and an organic solvent. The general formula (3) obtained by imidizing the polyimide precursor according to claim 1.

^{Wherein, R 1, R 2, R} 3, R 4, X and Z have the same meanings as in the general formula (1). ]
A polyimide having a structural unit represented by:   The polyimide according to claim 9, which has a water absorption of 2% or less.   11. The polyimide according to claim 9, wherein the polyimide has a glass transition temperature of 200 ° C. or more, a light transmittance at a wavelength of 400 nm of 60% or more, a birefringence of 0.1 or less, and a breaking elongation of 5% or more.   A polyimide varnish comprising the polyimide according to any one of claims 9 to 11 and an organic solvent.   A polyimide molded body comprising the polyimide according to claim 9.   The polyimide molded body according to claim 13, wherein the polyimide molded body is in the form of a layer, a film, a film, or a sheet.   A plastic substrate using the polyimide molded body according to claim 14.   The plastic substrate according to claim 15, which is used for a display element.   The plastic substrate according to claim 16, wherein the display element is a liquid crystal display or an organic electroluminescence display.   The display element provided with the plastic substrate in any one of Claims 15-17. It is a manufacturing method of the plastic substrate in any one of Claims 15-17, Comprising: The process of apply | coating the polyimide precursor varnish of Claim 8, or the polyimide varnish of Claim 12 on a support body, A step of drying, curing, and a step of peeling the polyimide molded body from the support;
A method of manufacturing a plastic substrate.

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