JP7264264B2 - Polyimide precursor composition and method for producing flexible electronic device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyimide precursor composition suitably used for electronic device applications such as flexible device substrates, and a method for producing a flexible electronic device.

Polyimide films have been widely used in fields such as electric/electronic devices and semiconductors due to their excellent heat resistance, chemical resistance, mechanical strength, electrical properties, dimensional stability, and the like. On the other hand, in recent years, with the advent of an advanced information society, the development of optical materials such as optical fibers and optical waveguides in the field of optical communication, and liquid crystal alignment films and protective films for color filters in the field of display devices is progressing. In the field of display devices in particular, studies on plastic substrates that are lightweight and excellent in flexibility as an alternative to glass substrates and development of displays that can be bent or rolled are being actively pursued.

In displays such as liquid crystal displays and organic EL displays, semiconductor elements such as TFTs are formed for driving each pixel. Therefore, the substrate is required to have heat resistance and dimensional stability. Polyimide films have excellent heat resistance, chemical resistance, mechanical strength, electrical properties, dimensional stability, and the like, and are therefore promising substrates for display applications.

Polyimide is generally colored in yellowish brown, which limits its use in transmissive devices such as liquid crystal displays equipped with a backlight. A polyimide film having excellent transparency has been developed, and expectations are rising for use as a substrate for display applications (see Patent Documents 1 to 3).

In general, it is difficult to maintain flatness of a flexible film, so it is difficult to uniformly and accurately form semiconductor elements such as TFTs, fine wiring, and the like on a flexible film. For example, in Patent Document 4, "a step of coating a specific precursor resin composition on a carrier substrate to form a solid polyimide resin film, a step of forming a circuit on the resin film, the circuit A method for manufacturing a flexible device, which is a display device or a light receiving device, including each step of peeling off a solid resin film on the surface of which is formed from the carrier substrate.

Further, in Patent Document 5, as a method of manufacturing a flexible device, elements and circuits necessary for the device are formed on a polyimide film/glass substrate laminate obtained by forming a polyimide film on a glass substrate. Later, a method is disclosed including exfoliating the glass substrate by irradiating a laser from the glass substrate side.

International Publication No. 2012/011590 International Publication No. 2013/179727 International Publication No. 2014/038715 JP 2010-202729 A International Publication No. 2018/221607 International Publication No. 2012/173204 International Publication No. 2015/080139

Mechanical peeling as described in Patent Document 4 has the advantage that it is simple and does not require additional equipment. It may damage the elements and circuits formed on the polyimide film when peeling from the polyimide film. On the other hand, laser peeling as described in Patent Document 5 can reduce the peel strength during peeling while ensuring high adhesion between the polyimide film and the glass substrate when forming elements and circuits. There is an advantage that the damage to the circuit is small. However, the equipment cost increases, such as the need for a laser irradiation device.

By the way, in Patent Document 6, a polyimide precursor solution obtained from 3,3′,4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine was added with monoethyl phosphate (Example 4) and monolauryl. Phosphate ester (Example 5), polyphosphoric acid (Example 6) are respectively added to the composition, but by adding these phosphorus compounds, the polyimide film formed on the substrate and the substrate A decrease in the peel strength of the film and the fabrication of flexible electronic devices are not described.

Furthermore, Patent Document 7 describes, as a comparative example, an example in which phosphoric acid (Comparative Example 2) and tributyl phosphate (Comparative Example 4) were added to a polyimide precursor solution having specific components. It is not described at all that the addition of a phosphorus compound lowers the peel strength between a polyimide film formed on a substrate and the substrate.

The present invention has been made in view of the conventional problems, and the main purpose thereof is to provide a polyimide precursor composition capable of producing a flexible electronic device using an industrially simple apparatus and process, and a flexible It aims at providing the manufacturing method of an electronic device.

A summary of the main disclosures of this application follows.

1. polyimide precursor,
P(=O)OH structure or P(=O)OR (wherein R has 4 or more carbon atoms A polyimide precursor composition (provided that it satisfies the following condition (A)), comprising: a phosphorus compound having a (alkyl group) structure; and a solvent.
(A) The polyimide precursor is not a polyimide precursor obtained only from 3,3′,4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine.
2. 2. The composition according to item 1, wherein the content of the phosphorus compound is 0.01 mol % or more based on the total monomer units of the polyimide precursor.
3. 3. The composition according to item 1 or 2, wherein the phosphorus compound does not contain a compound having an aryl group directly bonded to P.
4. 4. The composition according to any one of items 1 to 3, wherein the phosphorus compound has a molecular weight of less than 400.
5. The above item, wherein the polyimide precursor comprises a repeating unit selected from a structure represented by the following general formula (I) and a structure in which at least one of the amide structures in the general formula (I) is imidized. The composition according to any one of 1-4.

（一般式Ｉ中、Ｘ_１は４価の脂肪族基または芳香族基であり、Ｙ_１は２価の脂肪族基または芳香族基であり、Ｒ_１およびＲ_２は互いに独立して、水素原子、炭素数１～６のアルキル基または炭素数３～９のアルキルシリル基である。）
６． Ｘ_１が脂環構造を有する４価の基であり、Ｙ_１が脂環構造を有する２価の基である一般式（Ｉ）で表される繰り返し単位の含有量が、全繰り返し単位に対して、５０モル％以下であることを特徴とする上記項５に記載の組成物。
７． 一般式（Ｉ）中のＸ_１が芳香族環を有する４価の基であり、Ｙ_１が芳香族環を有する２価の基であることを特徴とする上記項５に記載の組成物。
８． 一般式（Ｉ）中のＸ_１が脂環構造を有する４価の基であり、Ｙ_１が芳香族環を有する２価の基であることを特徴とする上記項５に記載の組成物。
９． 一般式（Ｉ）中のＸ_１が芳香族環を有する４価の基であり、Ｙ_１が脂環構造を有する２価の基であることを特徴とする上記項５に記載の組成物。
１０． 一般式（Ｉ）のＸ_１が脂環構造を有する４価の基である繰り返し単位を全繰り返し単位中の６０％超の割合で含有すること（但し、Ｘ_１が脂環構造を有する４価の基であり且つＹ_１が脂環構造を有する２価の基である一般式（Ｉ）で表される繰り返し単位の含有量は、全繰り返し単位に対して、５０モル％以下である）を特徴とする上記項５に記載の組成物。
１１． （ａ）ポリイミド前駆体、Ｐ（＝Ｏ）ＯＨ構造またはＰ（＝Ｏ）ＯＲ（式中、Ｒは炭素数４以上のアルキル基）構造を有するリン化合物および溶媒を含有するポリイミド前駆体組成物を、基材上に塗布する工程、
（ｂ）前記基材上で前記ポリイミド前駆体を加熱処理し、前記基材上にポリイミドフィルムが積層された積層体を製造する工程、
（ｃ）前記積層体のポリイミドフィルム上に、導電体層および半導体層から選ばれる少なくとも1つの層を形成する工程、および
（ｄ）前記基材と前記ポリイミドフィルムとを、外力によって剥離する工程
を有するフレキシブル電子デバイスの製造方法。
１２． 前記ポリイミド前駆体組成物が、上記項１～１０のいずれか１項に記載ポリイミド前駆体組成物であることを特徴とする上記項１１に記載の製造方法。
１３． 前記基材が、ガラス板である上記項１１または１２に記載の製造方法。
１４． 前記基材と前記ポリイミドフィルムを剥離する工程において、レーザ照射を行わないことを特徴とする上記項１１～１３のいずれか１項に記載の製造方法。
１５． 基材とこの基材に形成されたポリイミドフィルムとを有する積層体の、前記基材とポリイミドフィルムの間の剥離強度を低下させる方法であって、
前記ポリイミドフィルム形成のためのポリイミド前駆体組成物が、Ｐ（＝Ｏ）ＯＨ構造またはＰ（＝Ｏ）ＯＲ（式中、Ｒは炭素数４以上のアルキル基）構造を有するリン化合物を含有することを特徴とする、積層体の剥離強度低下方法。
１６． 前記ポリイミド前駆体組成物が、上記項１～１０のいずれか１項に記載ポリイミド前駆体組成物であることを特徴とする上記項１５に記載の方法。
１７． 前記基材が、ガラス板である上記項１５または１６に記載の方法。

(In general formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, R ₁ and R ₂ are independently hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.)
6. X ₁ is a tetravalent group having an alicyclic structure, and Y ₁ is a divalent group having an alicyclic structure. 6. The composition according to item 5, wherein the content of the composition is 50 mol % or less.
7. 6. The composition according to item 5, wherein X ₁ in general formula (I) is a tetravalent group having an aromatic ring, and Y ₁ is a divalent group having an aromatic ring.
8. 6. The composition according to item 5, wherein X ₁ in general formula (I) is a tetravalent group having an alicyclic structure, and Y ₁ is a divalent group having an aromatic ring.
9. 6. The composition according to item 5, wherein X ₁ in general formula (I) is a tetravalent group having an aromatic ring, and Y ₁ is a divalent group having an alicyclic structure.
10. X ₁ of the general formula (I) contains a repeating unit that is a tetravalent group having an alicyclic structure in a proportion of more than 60% of all repeating units (provided that X ₁ is a tetravalent group having an alicyclic structure and Y ₁ is a divalent group having an alicyclic structure. 6. The composition according to item 5, characterized in that:
11. (a) a polyimide precursor composition containing a polyimide precursor, a phosphorus compound having a P (= O) OH structure or a P (= O) OR (wherein R is an alkyl group having 4 or more carbon atoms) structure and a solvent A step of applying onto the substrate,
(b) a step of heat-treating the polyimide precursor on the base material to produce a laminate in which a polyimide film is laminated on the base material;
(c) forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate; and (d) separating the base material and the polyimide film by an external force. A method of manufacturing a flexible electronic device comprising:
12. 12. The production method according to item 11 above, wherein the polyimide precursor composition is the polyimide precursor composition according to any one of items 1 to 10 above.
13. 13. The manufacturing method according to item 11 or 12, wherein the substrate is a glass plate.
14. 14. The manufacturing method according to any one of items 11 to 13, wherein laser irradiation is not performed in the step of separating the base material and the polyimide film.
15. A method for reducing the peel strength between a substrate and a polyimide film of a laminate having a substrate and a polyimide film formed on the substrate, comprising:
Polyimide precursor composition for forming the polyimide film contains a phosphorus compound having a P (= O) OH structure or P (= O) OR (wherein R is an alkyl group having 4 or more carbon atoms) structure A method for reducing the peel strength of a laminate, characterized by:
16. 16. The method according to item 15 above, wherein the polyimide precursor composition is the polyimide precursor composition according to any one of items 1 to 10 above.
17. 17. The method according to item 15 or 16, wherein the substrate is a glass plate.

ADVANTAGE OF THE INVENTION According to this invention, the polyimide precursor composition which can manufacture a flexible electronic device with an industrially simple apparatus and process can be provided. Moreover, according to the present invention, it is possible to provide a simple method for manufacturing a flexible electronic device using a polyimide film as a substrate. The use of the polyimide precursor composition of the present invention can appropriately reduce the peel strength between the substrate and the polyimide film. Therefore, it is possible to manufacture a flexible electronic device by using a simple apparatus and process, and it is possible to manufacture the device with a high yield with little possibility of damaging the element.

In this application, the term "flexible (electronic) device" means that the device itself is flexible, and the device is usually completed by forming semiconductor layers (elements such as transistors and diodes) on a substrate. A "flexible (electronic) device" is distinguished from a device such as a COF (Chip On Film) in which a "hard" semiconductor element such as an IC chip is mounted on a conventional FPC (Flexible Printed Circuit Board). However, in order to operate or control the "flexible (electronic) device" of the present application, "hard" semiconductor elements such as IC chips are mounted on the flexible substrate, electrically connected, and used in combination There is nothing wrong with doing Suitable flexible (electronic) devices include display devices such as liquid crystal displays, organic EL displays, and electronic papers, and light receiving devices such as solar cells and CMOS.

The polyimide precursor composition of the present invention will be described below, and then the method for producing a flexible electronic device will be described.

<<polyimide precursor composition>>
A polyimide precursor composition for forming a polyimide film contains a polyimide precursor, a phosphorus compound and a solvent. Both the polyimide precursor and the phosphorus compound are dissolved in the solvent.
In this application, the term "polyimide precursor" is used to mean a precursor capable of forming a polyimide in a polyimide film. That is, the term "polyimide precursor" includes polyamic acids and derivatives (precisely defined by formula (I)), partially imidized polyamic acids and derivatives that have undergone partial imidization, and polyimides, Both dissolve in solvents.

The polyimide precursor has the following general formula (I):

（一般式Ｉ中、Ｘ_１は４価の脂肪族基または芳香族基であり、Ｙ_１は２価の脂肪族基または芳香族基であり、Ｒ_１およびＲ_２は互いに独立して、水素原子、炭素数１～６のアルキル基または炭素数３～９のアルキルシリル基である。）
で表される繰り返し単位を有する。特に好ましくは、Ｒ_１およびＲ_２が水素原子であるポリアミック酸である。

(In general formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, R ₁ and R ₂ are independently hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.)
It has a repeating unit represented by Particularly preferred are polyamic acids in which R ₁ and R ₂ are hydrogen atoms.

Also, the partially imidized polyimide precursor contains repeating units in which at least one of the two amide structures in general formula (I) is imidized.

A polyimide formed from a polyimide precursor having a repeating unit represented by general formula (I) has the following general formula (II):

（式中、Ｘ_１は４価の脂肪族基または芳香族基であり、Ｙ_１は２価の脂肪族基または芳香族基である。）
で表される繰り返し単位を有する。溶解可能なポリイミドである場合には、「ポリイミド前駆体」として、ポリイミド前駆体組成物中に含有させることができる。

(Wherein, X ₁ is a tetravalent aliphatic or aromatic group, and Y ₁ is a divalent aliphatic or aromatic group.)
It has a repeating unit represented by When it is a soluble polyimide, it can be contained as a "polyimide precursor" in the polyimide precursor composition.

The chemical structures of such polyimides are shown below, the structures of X ₁ and Y ₂ in the repeating units (general formulas (I) and (II)) and the monomers (tetracarboxylic acid component, diamine component , and other components), and then the manufacturing method will be described.

As used herein, the tetracarboxylic acid component means a tetracarboxylic acid, a tetracarboxylic dianhydride, and other tetracarboxylic acid silyl esters, tetracarboxylic acid esters, tetracarboxylic acid chlorides, and the like, which are used as raw materials for producing polyimide. Contains carboxylic acid derivatives. Although not particularly limited, it is convenient to use a tetracarboxylic dianhydride in terms of production, and in the following explanation, an example using a tetracarboxylic dianhydride as a tetracarboxylic acid component will be described. Also, the diamine component is a diamine compound having two amino groups (--NH ₂ ), which is used as a raw material for producing polyimide.

Also, in this specification, the polyimide film means both the one formed on the (carrier) substrate and present in the laminate, and the film after peeling off the substrate. Moreover, the material which comprises the polyimide film, ie, the material obtained by heat-processing (imidating) the polyimide precursor composition, may be called "polyimide material."

The polyimide contained in the polyimide film is not particularly limited, and the tetracarboxylic acid component and the diamine component are composed of polyimides appropriately selected from aromatic compounds and aliphatic compounds. The aliphatic compound of the diamine component is preferably a cycloaliphatic compound. Examples of polyimides include wholly aromatic polyimides, semi-alicyclic polyimides, and wholly alicyclic polyimides.

Although not particularly limited, since the resulting polyimide material has excellent heat resistance, X ₁ in the general formula (I) is a tetravalent group having an aromatic ring, and Y ₁ has an aromatic ring. A divalent group is preferred. In addition, since the resulting polyimide material has excellent heat resistance and at the same time excellent transparency, X ₁ is a tetravalent group having an alicyclic structure, and Y ₁ is a divalent group having an aromatic ring. preferable. In addition, since the resulting polyimide material has excellent heat resistance and excellent dimensional stability, X ₁ is a tetravalent group having an aromatic ring, and Y ₁ is a divalent group having an alicyclic structure. is preferred.

From the viewpoint of the properties of the resulting polyimide material, such as transparency, mechanical properties, or heat resistance, X ₁ is a tetravalent group having an alicyclic structure, and Y ₁ is a divalent group having an alicyclic structure. The content of the repeating unit represented by formula (I), which is a group, is preferably 50 mol% or less, more preferably 30 mol% or less or less than 30 mol%, more preferably 10 mol%, based on all repeating units % or less.

In one embodiment, the content of one or more repeating units of the above formula (I), wherein X ₁ is a tetravalent group having an aromatic ring and Y ₁ is a divalent group having an aromatic ring However, the total is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, particularly preferably 100 mol%, based on all repeating units. Preferably. In this embodiment, the polyimide preferably contains fluorine atoms, especially when a highly transparent polyimide material is desired. That is, the polyimide is a repeating unit of the general formula (I) in which X ₁ is a tetravalent group having an aromatic ring containing a fluorine atom and / or Y ₁ has an aromatic ring containing a fluorine atom 2 It preferably contains at least one repeating unit represented by the general formula (I), which is a valent group.

In one embodiment, the polyimide is one of the repeating units represented by the general formula (I), wherein X ₁ is a tetravalent group having an alicyclic structure and Y ₁ is a divalent group having an aromatic ring. The total content of the above is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, particularly preferably 90 mol% or more, based on all repeating units. 100 mol % is preferred.

In one embodiment, the polyimide is one or more repeating units represented by the above formula (I), wherein X ₁ is a tetravalent group having an aromatic ring and Y ₁ is a divalent group having an alicyclic structure. The total content of all repeating units is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, particularly preferably 100 Mole % is preferred.

<X ₁ and tetracarboxylic acid component>
The tetravalent group having an aromatic ring for X ₁ is preferably a tetravalent group having 6 to 40 carbon atoms and having an aromatic ring.

Examples of the tetravalent group having an aromatic ring include the following.

（式中、Ｚ_１は直接結合、または、下記の２価の基：

(Wherein, Z ₁ is a direct bond or the following divalent group:

のいずれかである。ただし、式中のＺ_２は、２価の有機基、Ｚ_３、Ｚ_４はでそれぞれ独立にアミド結合、エステル結合、カルボニル結合であり、Ｚ_５は芳香環を含む有機基である。）

is either However, _Z2 in the formula is a divalent organic group, Z3 _{and Z4} are each independently an amide bond, an ester bond and a carbonyl bond, and _Z5 is an organic group containing an aromatic ring. )

Z ₂ specifically includes an aliphatic hydrocarbon group having 2 to 24 carbon atoms and an aromatic hydrocarbon group having 6 to 24 carbon atoms.

Z ₅ specifically includes an aromatic hydrocarbon group having 6 to 24 carbon atoms.

As the tetravalent group having an aromatic ring, the following groups are particularly preferable because they can achieve both high heat resistance and high transparency of the resulting polyimide film.

（式中、Ｚ_１は直接結合、または、へキサフルオロイソプロピリデン結合である。）

(In the formula, Z ₁ is a direct bond or a hexafluoroisopropylidene bond.)

Here, it is more preferable that _Z1 is a direct bond because the obtained polyimide film can have both high heat resistance, high transparency, and a low coefficient of linear thermal expansion.

In addition, as a preferred group, in the above formula (9), Z ₁ is the following formula (3A):

で表されるフルオレニル含有基である化合物が挙げられる。Ｚ_１１およびＺ_１２はそれぞれ独立に、好ましくは同一で、単結合または２価の有機基である。Ｚ_１１およびＺ_１２としては、芳香環を含む有機基が好ましく、例えば式（３Ａ１）：

and a compound that is a fluorenyl-containing group represented by: Z ₁₁ and Z ₁₂ are each independently, preferably the same, a single bond or a divalent organic group. Z ₁₁ and Z ₁₂ are preferably organic groups containing an aromatic ring, such as formula (3A1):

（Ｚ_１３およびＺ_１４は、互いに独立に単結合、－ＣＯＯ－、－ＯＣＯ－または－Ｏ－であり、ここでＺ_１４がフルオレニル基に結合した場合、Ｚ_１３が－ＣＯＯ－、－ＯＣＯ－または－Ｏ－でＺ_１４が単結合の構造が好ましく；Ｒ_９１は炭素数１～４のアルキル基またはフェニル基であり、好ましくはメチルであり、ｎは０～４の整数であり、好ましくは１である。）
で表される構造が好ましい。

(Z ₁₃ and Z ₁₄ are each independently a single bond, -COO-, -OCO- or -O-, where when Z ₁₄ is bonded to a fluorenyl group, Z ₁₃ is -COO-, -OCO- or -O- and Z ₁₄ is preferably a single bond structure; R ₉₁ is an alkyl group having 1 to 4 carbon atoms or a phenyl group, preferably methyl; n is an integer of 0 to 4, preferably 1.)
A structure represented by is preferred.

Examples of the tetracarboxylic acid component that gives the repeating unit of general formula (I) in which X ₁ is a tetravalent group having an aromatic ring include 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane , 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid, pyromellitic acid, 3,3′,4,4′-benzophenone Tetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 4,4'-oxydiphthalic acid, bis(3,4-dicarboxy phenyl)sulfone, m-terphenyl-3,4,3′,4′-tetracarboxylic acid, p-terphenyl-3,4,3′,4′-tetracarboxylic acid, biscarboxyphenyldimethylsilane, bisdi Carboxyphenoxydiphenyl sulfide, sulfonyldiphthalic acid, and their derivatives such as tetracarboxylic dianhydrides, tetracarboxylic acid silyl esters, tetracarboxylic acid esters and tetracarboxylic acid chlorides. Examples of tetracarboxylic acid components that give repeating units of general formula (I), wherein X ₁ is a tetravalent group having an aromatic ring containing a fluorine atom, include 2,2-bis(3,4-dicarboxy phenyl)hexafluoropropane and its derivatives such as tetracarboxylic dianhydride, tetracarboxylic acid silyl ester, tetracarboxylic acid ester and tetracarboxylic acid chloride. Furthermore, as a preferred compound, (9H-fluorene-9,9-diyl)bis(2-methyl-4,1-phenylene)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate) is mentioned. The tetracarboxylic acid component may be used alone or in combination of multiple types.

The tetravalent group having an alicyclic structure of X ₁ is preferably a tetravalent group having an alicyclic structure having 4 to 40 carbon atoms, at least one aliphatic 4- to 12-membered ring, more preferably aliphatic More preferably it has a 4-membered ring or an aliphatic 6-membered ring. Preferred tetravalent groups having an aliphatic 4-membered ring or an aliphatic 6-membered ring include the following.

（式中、Ｒ_３１～Ｒ_３８は、それぞれ独立に直接結合、または、２価の有機基である。Ｒ_４１～Ｒ_４７は、それぞれ独立に 式：－ＣＨ_２－、－ＣＨ＝ＣＨ－、－ＣＨ_２ＣＨ_２－、－Ｏ－、－Ｓ－で表される基よりなる群から選択される１種を示す。Ｒ_４８は芳香環もしくは脂環構造を含む有機基である。）

(Wherein, R ₃₁ to R ₃₈ are each independently a direct bond or a divalent organic group. R ₄₁ to R ₄₇ are each independently Formula: -CH ₂ -, -CH=CH-, —CH ₂ CH ₂ —, —O—, and —S—, wherein R ₄₈ is an organic group containing an aromatic ring or an alicyclic structure.)

Specifically, R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ and R ₃₈ are a direct bond, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or Oxygen atom (--O--), sulfur atom (--S--), carbonyl bond, ester bond and amide bond.

Examples of the organic group containing an aromatic ring as R ₄₈ include the following.

（式中、Ｗ_１は直接結合、または、２価の有機基であり、ｎ_１１～ｎ_１３は、それぞれ独立に０～４の整数を表し、Ｒ_５１、Ｒ_５２、Ｒ_５３は、それぞれ独立に炭素数１～６のアルキル基、ハロゲン基、水酸基、カルボキシル基、またはトリフルオロメチル基である。）

(Wherein, W ₁ is a direct bond or a divalent organic group, n ₁₁ to n ₁₃ each independently represent an integer of 0 to 4, R ₅₁ , R ₅₂ and R ₅₃ each independently is an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, a carboxyl group, or a trifluoromethyl group.)

Specific examples of W ₁ include a direct bond, a divalent group represented by the following formula (5), and a divalent group represented by the following formula (6).

（式（６）中のＲ_６１～Ｒ_６８は、それぞれ独立に直接結合または前記式（５）で表される２価の基のいずれかを表す。）

(R ₆₁ to R ₆₈ in formula (6) each independently represent either a direct bond or a divalent group represented by formula (5) above.)

As the tetravalent group having an alicyclic structure, the following groups are particularly preferable because the obtained polyimide can have both high heat resistance, high transparency, and a low coefficient of linear thermal expansion.

Examples of the tetracarboxylic acid component that gives the repeating unit of formula (I) in which X ₁ is a tetravalent group having an alicyclic structure include 1,2,3,4-cyclobutanetetracarboxylic acid, isopropylidene diphenoxybis phthalic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, [1,1'-bi(cyclohexane)]-3,3',4,4'-tetracarboxylic acid, [1,1'-bi (cyclohexane)]-2,3,3′,4′-tetracarboxylic acid, [1,1′-bi(cyclohexane)]-2,2′,3,3′-tetracarboxylic acid, 4,4′- methylenebis(cyclohexane-1,2-dicarboxylic acid), 4,4'-(propane-2,2-diyl)bis(cyclohexane-1,2-dicarboxylic acid), 4,4'-oxybis(cyclohexane-1,2 -dicarboxylic acid), 4,4′-thiobis(cyclohexane-1,2-dicarboxylic acid), 4,4′-sulfonylbis(cyclohexane-1,2-dicarboxylic acid), 4,4′-(dimethylsilanediyl) Bis(cyclohexane-1,2-dicarboxylic acid), 4,4′-(tetrafluoropropane-2,2-diyl)bis(cyclohexane-1,2-dicarboxylic acid), octahydropentalene-1,3,4 ,6-tetracarboxylic acid, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid, 6-(carboxymethyl)bicyclo[2.2.1]heptane-2,3,5 -tricarboxylic acid, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic acid, bicyclo[2.2.2]oct-5-ene-2,3,7,8-tetracarboxylic acid acid, tricyclo[4.2.2.02,5]decane-3,4,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5]dec-7-ene-3,4, 9,10-tetracarboxylic acid, 9-oxatricyclo[4.2.1.02,5]nonane-3,4,7,8-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone- α′-spiro-2″-norbornane 5,5″,6,6″-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2c,3c, 6c,7c-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2t,3t,6c,7c-tetracarboxylic acid and tetracarboxylic dianhydrides thereof, Derivatives such as tetracarboxylic acid silyl esters, tetracarboxylic acid esters, and tetracarboxylic acid chlorides can be mentioned. The tetracarboxylic acid component may be used alone or in combination of multiple types.

< _Y1 and diamine component>
The divalent group having an aromatic ring for Y ₁ preferably has 6 to 40 carbon atoms, more preferably a divalent group having 6 to 20 carbon atoms and having an aromatic ring.

Examples of the divalent group having an aromatic ring include the following.

（式中、Ｗ_１は直接結合、または、２価の有機基であり、ｎ_１１～ｎ_１３は、それぞれ独立に０～４の整数を表し、Ｒ_５１、Ｒ_５２、Ｒ_５３は、それぞれ独立に炭素数１～６のアルキル基、ハロゲン基、水酸基、カルボキシル基、またはトリフルオロメチル基である。）

(Wherein, W ₁ is a direct bond or a divalent organic group, n ₁₁ to n ₁₃ each independently represent an integer of 0 to 4, R ₅₁ , R ₅₂ and R ₅₃ each independently is an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, a carboxyl group, or a trifluoromethyl group.)

Specific examples of W ₁ include a direct bond, a divalent group represented by the following formula (5), and a divalent group represented by the following formula (6).

（式（６）中のＲ_６１～Ｒ_６８は、それぞれ独立に直接結合または前記式（５）で表される２価の基のいずれかを表す。）

(R ₆₁ to R ₆₈ in formula (6) each independently represent either a direct bond or a divalent group represented by formula (5) above.)

Here, since the obtained polyimide can have both high heat resistance, high transparency, and a low coefficient of linear thermal expansion, W ₁ is a direct bond or a formula: -NHCO-, -CONH-, -COO-, -OCO- One selected from the group consisting of groups represented by is particularly preferred. In addition, W ₁ is one selected from the group consisting of groups represented by the formulas: -NHCO-, -CONH-, -COO-, and -OCO-, wherein R ₆₁ to R ₆₈ are direct bonds. Any one of the divalent groups represented by formula (6) is also particularly preferred.

In addition, as a preferable group, in the above formula (4), W ₁ is represented by the following formula (3B):

で表されるフルオレニル含有基である化合物が挙げられる。Ｚ_１１およびＺ_１２はそれぞれ独立に、好ましくは同一で、単結合または２価の有機基である。Ｚ_１１およびＺ_１２としては、芳香環を含む有機基が好ましく、例えば式（３Ｂ１）：

and a compound that is a fluorenyl-containing group represented by: Z ₁₁ and Z ₁₂ are each independently, preferably the same, a single bond or a divalent organic group. Z ₁₁ and Z ₁₂ are preferably organic groups containing aromatic rings, such as formula (3B1):

（Ｚ_１３およびＺ_１４は、互いに独立に単結合、－ＣＯＯ－、－ＯＣＯ－または－Ｏ－であり、ここでＺ_１４がフルオレニル基に結合した場合、Ｚ_１３が－ＣＯＯ－、－ＯＣＯ－または－Ｏ－でＺ_１４が単結合の構造が好ましく；Ｒ_９１は炭素数１～４のアルキル基またはフェニル基であり、好ましくはフェニルであり、ｎは０～４の整数であり、好ましくは１である。）
で表される構造が好ましい。

(Z ₁₃ and Z ₁₄ are each independently a single bond, -COO-, -OCO- or -O-, where when Z ₁₄ is bonded to a fluorenyl group, Z ₁₃ is -COO-, -OCO- or -O- and Z ₁₄ is preferably a single bond; R ₉₁ is an alkyl group having 1 to 4 carbon atoms or a phenyl group, preferably phenyl; n is an integer of 0 to 4, preferably 1.)
A structure represented by is preferred.

Another preferred group is a compound in which _W1 is a phenylene group in the above formula (4), that is, a terphenyldiamine compound, and particularly preferred is a compound in which all are para bonds.

Another preferred group includes compounds in which R ₆₁ and R ₆₂ are 2,2-propylidene groups in the structure of formula (4) above where W ₁ is the first phenyl ring of formula (6).

As still another preferred group, in the above formula (4), W ₁ is represented by the following formula (3B2):

で表される化合物が挙げられる。

The compound represented by is mentioned.

Examples of diamine components that give repeating units of general formula (I) wherein Y ₁ is a divalent group having an aromatic ring include p-phenylenediamine, m-phenylenediamine, benzidine, 3,3′-diamino- biphenyl, 2,2′-bis(trifluoromethyl)benzidine, 3,3′-bis(trifluoromethyl)benzidine, m-tolidine, 4,4′-diaminobenzanilide, 3,4′-diaminobenzanilide, N,N'-bis(4-aminophenyl)terephthalamide, N,N'-p-phenylenebis(p-aminobenzamide), 4-aminophenoxy-4-diaminobenzoate, bis(4-aminophenyl)terephthalate, Biphenyl-4,4'-dicarboxylic acid bis(4-aminophenyl) ester, p-phenylene bis(p-aminobenzoate), bis(4-aminophenyl)-[1,1'-biphenyl]-4,4' -dicarboxylate, [1,1′-biphenyl]-4,4′-diylbis(4-aminobenzoate), 4,4′-oxydianiline, 3,4′-oxydianiline, 3,3′- Oxydianiline, p-methylenebis(phenylenediamine), 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene , 4,4′-bis(4-aminophenoxy)biphenyl, 4,4′-bis(3-aminophenoxy)biphenyl, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2 , 2-bis(4-aminophenyl)hexafluoropropane, bis(4-aminophenyl)sulfone, 3,3′-bis(trifluoromethyl)benzidine, 3,3′-bis((aminophenoxy)phenyl)propane , 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, bis(4-(4-aminophenoxy)diphenyl)sulfone, bis(4-(3-aminophenoxy)diphenyl)sulfone, octa fluorobenzidine, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2, 4-bis(4-aminoanilino)-6-amino-1,3,5-triazine, 2,4-bis(4-aminoanilino)-6-methylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino)-6-ethylamino-1,3,5-triazine, 2,4-bis(4-aminoanilino)-6-anilino-1,3,5-triazine. Examples of the diamine component that gives the repeating unit of general formula (I), wherein Y ₁ is a divalent group having an aromatic ring containing a fluorine atom, include 2,2′-bis(trifluoromethyl)benzidine, 3 ,3′-bis(trifluoromethyl)benzidine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2 '-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. Additionally, preferred diamine compounds include 4,4′-(((9H-fluorene-9,9-diyl)bis([1,1′-biphenyl]-5,2-diyl))bis(oxy))diamine, [1,1′:4′,1″-terphenyl]-4,4″-diamine, 4,4′-([1,1′-binaphthalene]-2,2′-diylbis(oxy))diamine mentioned. A diamine component may be used individually and can also be used in combination of multiple types.

The divalent group having an alicyclic structure for Y ₁ is preferably a divalent group having an alicyclic structure having 4 to 40 carbon atoms, at least one aliphatic 4- to 12-membered ring, more preferably aliphatic It is more preferred to have a 6-membered ring.

Examples of divalent groups having an alicyclic structure include the following.

（式中、Ｖ_１、Ｖ_２は、それぞれ独立に直接結合、または、２価の有機基であり、ｎ_２１～ｎ_２６は、それぞれ独立に０～４の整数を表し、Ｒ_８１～Ｒ_８６は、それぞれ独立に炭素数１～６のアルキル基、ハロゲン基、水酸基、カルボキシル基、またはトリフルオロメチル基であり、Ｒ_９１、Ｒ_９２、Ｒ_９３は、それぞれ独立に 式：－ＣＨ_２－、－ＣＨ＝ＣＨ－、－ＣＨ_２ＣＨ_２－、－Ｏ－、－Ｓ－で表される基よりなる群から選択される１種である。）

(Wherein, V ₁ and V ₂ are each independently a direct bond or a divalent organic group, n ₂₁ to n ₂₆ each independently represent an integer of 0 to 4, R ₈₁ to R ₈₆ each independently represents an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, a carboxyl group or a trifluoromethyl group; R ₉₁ , R ₉₂ and R ₉₃ each independently represent the formula: —CH ₂ —, It is one selected from the group consisting of groups represented by -CH=CH-, -CH ₂ CH ₂ -, -O- and -S-.)

Specific examples of V ₁ and V ₂ include a direct bond and a divalent group represented by formula (5) above.

As the divalent group having an alicyclic structure, the following groups are particularly preferable because they can achieve both high heat resistance and a low coefficient of linear thermal expansion of the resulting polyimide.

脂環構造を有する２価の基としては、中でも、下記のものが好ましい。

Among the divalent groups having an alicyclic structure, the following are preferred.

Examples of the diamine component that gives the repeating unit of general formula (I) wherein Y ₁ is a divalent group having an alicyclic structure include 1,4-diaminocyclohexane and 1,4-diamino-2-methylcyclohexane. , 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1 ,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,3-diamino Cyclobutane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, diaminobicycloheptane, diaminomethylbicycloheptane, diaminooxybicycloheptane, diaminomethyloxybicycloheptane, isophoronediamine, diaminotricyclohexane Decane, diaminomethyltricyclodecane, bis(aminocyclohexyl)methane, bis(aminocyclohexyl)isopropylidene, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl -1,1′-spirobiindane, 6,6′-bis(4-aminophenoxy)-3,3,3′,3′-tetramethyl-1,1′-spirobiindane. A diamine component may be used individually and can also be used in combination of multiple types.

In a preferred embodiment of the polyimide precursor invention, the polyimide precursor is a polyimide precursor obtained only from 3,3′,4,4′-biphenyltetracarboxylic acid derivative (dianhydride) and p-phenylenediamine. isn't it. Preferably, X ₁ in general formula (I) is derived from a 3,3′,4,4′-biphenyltetracarboxylic acid derivative (s-BPDA etc.) and Y ₁ is derived from p-phenylenediamine (PPD) The proportion of repeating units is 25 mol % or less, more preferably 10 mol % or less, preferably 0 mol % (excluding at least one of s-BPDA and the like and PPD) in all repeating units.

In a preferred embodiment of the invention relating to the polyimide precursor, the polyimide precursor and the polyimide are a tetracarboxylic acid derivative (dianhydride) having an aromatic ring and not containing fluorine atoms and a tetracarboxylic acid derivative (dianhydride) having an aromatic ring and containing fluorine atoms. It is not a polyimide precursor and a polyimide obtained only from a diamine compound that does not contain. That is, at least one of X ₁ and Y ₁ in general formula (I) preferably contains a repeating unit that is a group having an alicyclic structure or a group having an aromatic ring containing a fluorine atom. Preferably, X ₁ in general formula (I) is a group having an aromatic ring (excluding those containing fluorine) and Y ₁ is a group having an aromatic ring (excluding those containing fluorine) The proportion of repeating units is 25 mol% or less, more preferably 10 mol% or less, and 0 mol% of all repeating units (at least one of X ₁ and Y ₁ has an aromatic ring and a fluorine are not groups containing no atoms) are also preferred.

As the tetracarboxylic acid component and the diamine component that give the repeating unit represented by the general formula (I), aliphatic tetracarboxylic acids (especially dianhydrides) other than alicyclic and/or aliphatic diamines are used. However, the content thereof is preferably 30 mol% or less or less than 30 mol%, more preferably 20 mol% or less, still more preferably 10 mol% or less, relative to the total 100 mol% of the tetracarboxylic acid component and the diamine component. It is preferably mol % or less (including 0%).

Among the above, in a preferred embodiment of the present invention, repeating units in which X ₁ in general formula (I) is a tetravalent group having an alicyclic structure account for more than 60%, more preferably 70 mol, of all repeating units. % or more, more preferably 80 mol % or more, still more preferably 90 mol % or more, and particularly preferably 100 mol % or more. When the alicyclic structure is less than 100%, X ₁ is preferably a tetravalent group having an aromatic ring in the remainder. Preferred tetravalent groups having an alicyclic structure and tetravalent groups having an aromatic ring are as described above. In addition, Y ₁ may be either a divalent group having an aromatic ring or a divalent group having an alicyclic structure, but as described above, X ₁ is a tetravalent group having _an alicyclic structure, is a divalent group having an alicyclic structure. It is preferably less than mol %, more preferably 10 mol % or less.

In another preferred embodiment of the present invention, it is preferable that the polyimide (and the polyimide material) has a breaking strength of 80 MPa or more when formed into a film. As the breaking strength, for example, a value obtained from a film having a thickness of about 5 to 100 μm can be used. Moreover, this breaking strength is a value obtained for a film obtained by heating a coating film of a polyimide precursor solution composition or a polyimide solution composition, preferably at a maximum temperature of 310°C.

A polyimide precursor can be produced from the above tetracarboxylic acid component and diamine component. _The polyimide precursor used in the present invention (polyimide precursor containing at least one repeating unit represented by the formula (I) ₎ is
1) Polyamic acid (R ₁ and R ₂ are hydrogen),
2) polyamic acid ester (at least part of R ₁ and R ₂ is an alkyl group),
3) 4) polyamic acid silyl ester (at least a portion of R ₁ and R ₂ are alkylsilyl groups),
can be classified into Polyimide precursors can be easily produced by the following production methods for each of these classifications. However, the method for producing the polyimide precursor used in the present invention is not limited to the following production method.

1) Polyamic acid A polyimide precursor is prepared by mixing a tetracarboxylic acid dianhydride as a tetracarboxylic acid component and a diamine component in a solvent in approximately equimolar amounts, preferably the molar ratio of the diamine component to the tetracarboxylic acid component number/moles of tetracarboxylic acid component] is preferably from 0.90 to 1.10, more preferably from 0.95 to 1.05. It can be suitably obtained as a polyimide precursor solution by reacting while.

Although not limited, more specifically, diamine is dissolved in an organic solvent or water, and tetracarboxylic dianhydride is gradually added to this solution while stirring, and the temperature is adjusted to 0 to 120°C, preferably 5 A polyimide precursor is obtained by stirring in the range of ~80°C for 1 to 72 hours. When the reaction is carried out at 80° C. or higher, the molecular weight fluctuates depending on the temperature history during polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be stably produced. The order of addition of the diamine and the tetracarboxylic dianhydride in the above production method is preferable because the molecular weight of the polyimide precursor tends to increase. In addition, it is possible to reverse the order of addition of the diamine and the tetracarboxylic dianhydride in the production method described above, which is preferable because the precipitates are reduced. When water is used as a solvent, imidazoles such as 1,2-dimethylimidazole, or a base such as triethylamine, with respect to the carboxyl group of the polyamic acid to be generated (polyimide precursor), preferably 0.8 equivalents It is preferable to add in the above amount.

2) Polyamic Acid Ester A tetracarboxylic acid dianhydride is reacted with any alcohol to obtain a diester dicarboxylic acid, which is then reacted with a chlorinating reagent (thionyl chloride, oxalyl chloride, etc.) to obtain a diester dicarboxylic acid chloride. The diester dicarboxylic acid chloride and diamine are stirred at −20 to 120° C., preferably −5 to 80° C. for 1 to 72 hours to obtain a polyimide precursor. When the reaction is carried out at 80° C. or higher, the molecular weight fluctuates depending on the temperature history during polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be stably produced. A polyimide precursor can also be easily obtained by subjecting a diester dicarboxylic acid and a diamine to dehydration condensation using a phosphorus-based condensing agent, a carbodiimide condensing agent, or the like.

Since the polyimide precursor obtained by this method is stable, it can be purified by reprecipitation by adding a solvent such as water or alcohol.

3) Polyamic acid silyl ester (indirect method)
A diamine and a silylating agent are reacted in advance to obtain a silylated diamine. If necessary, the silylated diamine is purified by distillation or the like. Then, the silylated diamine is dissolved in the dehydrated solvent, and tetracarboxylic dianhydride is gradually added while stirring, and the Stirring for ~72 hours gives the polyimide precursor. When the reaction is carried out at 80° C. or higher, the molecular weight fluctuates depending on the temperature history during polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be stably produced.

4) Polyamic acid silyl ester (direct method)
The polyamic acid solution obtained by method 1) and the silylating agent are mixed and stirred at 0 to 120° C., preferably 5 to 80° C. for 1 to 72 hours to obtain a polyimide precursor. When the reaction is carried out at 80° C. or higher, the molecular weight fluctuates depending on the temperature history during polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be stably produced.

Using a chlorine-free silylating agent as the silylating agent used in method 3) and method 4) eliminates the need to purify the silylated polyamic acid or the resulting polyimide. preferred. The chlorine atom-free silylating agent includes N,O-bis(trimethylsilyl)trifluoroacetamide, N,O-bis(trimethylsilyl)acetamide and hexamethyldisilazane. N,O-bis(trimethylsilyl)acetamide and hexamethyldisilazane are particularly preferred because they do not contain fluorine atoms and are low in cost.

In the silylation reaction of diamine in method 3), an amine-based catalyst such as pyridine, piperidine, and triethylamine can be used to promote the reaction. This catalyst can be used as it is as a polymerization catalyst for the polyimide precursor.

Solvents used in preparing the polyimide precursor include water and, for example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3 -Aprotic solvents such as dimethyl-2-imidazolidinone and dimethyl sulfoxide are preferred, and any type of solvent can be used without any problem as long as the raw material monomer components and the polyimide precursor to be formed dissolve. The structure is not limited. Solvents include water, amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone , γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone and other cyclic ester solvents, ethylene carbonate, propylene carbonate and other carbonate solvents, triethylene glycol and other glycol solvents, m-cresol, p-cresol, 3 Phenolic solvents such as -chlorophenol and 4-chlorophenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethylsulfoxide and the like are preferably employed. In addition, other common organic solvents, namely phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran. , dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, turpene, mineral spirits, petroleum Naphtha-based solvents and the like can also be used. In addition, a solvent can also be used in combination of multiple types.

The logarithmic viscosity of the polyimide precursor is not particularly limited, but the logarithmic viscosity in an N,N-dimethylacetamide solution having a concentration of 0.5 g/dL at 30° C. is 0.2 dL/g or more, more preferably 0.3 dL/g. Above, it is particularly preferably 0.4 dL/g or more. When the logarithmic viscosity is 0.2 dL/g or more, the molecular weight of the polyimide precursor is high, and the obtained polyimide is excellent in mechanical strength and heat resistance.

As the imidization rate of the polyimide precursor, a wide range of about 0% (5% or less) to about 100% (95% or more) can be used. The polyimide precursors (polyamic acid, polyamic acid ester, polyamic acid silyl ester) obtained by the above method have a low imidization rate. These can be imidized in a solution (thermal imidization, chemical imidization) to promote imidization and adjust the imidization rate to a desired level. For example, by stirring the polyamic acid solution at a temperature of 80 to 230° C., preferably 120 to 200° C. for 1 to 24 hours, an imidized polyimide precursor can be obtained. If the polyimide is solvent-soluble, the polyimide obtained by depositing the polyimide by putting the reaction mixture after the imidization reaction into a poor solvent, or a solution of a polyimide precursor (low imidization rate) (if necessary, imidization containing a catalyst and a dehydrating agent) is, for example, cast on a carrier substrate, dried by heat treatment, and imidized (thermal imidization, chemical imidization), and the resulting polyimide is dissolved in a solvent. may be used in polyimide precursors for film production.

<Phosphorus compound>
Usable phosphorus compounds are compounds having at least one structure selected from P(=O)OH and P(=O)OR (R is an alkyl group having 4 or more carbon atoms) in the molecule. The phosphorus compound preferably does not have an aryl group directly bonded to the phosphorus atom P, and more preferably does not contain an aryl group in the molecule. Phosphorus compounds can have one or more phosphorus atoms in the molecule.

In one preferred embodiment of the invention, the phosphorus compound contains only one phosphorus atom. Compounds containing one phosphorus atom include compounds represented by formula (P).

式中、Ｒ_１～Ｒ_３の少なくとも１つの基は、ＯＨまたは炭素数４以上のアルコキシ基を表し、残りの基は独立してＯＨ、アルコキシ基、Ｈおよびアルキル基から選ばれる基を表す。

In the formula, at least one group of R ₁ to R ₃ represents OH or an alkoxy group having 4 or more carbon atoms, and the remaining groups independently represent groups selected from OH, alkoxy groups, H and alkyl groups.

The alkoxy group having 4 or more carbon atoms preferably includes an alkoxy group having 4 to 18 carbon atoms, more preferably 4 to 12 carbon atoms. These may be linear, branched or alicyclic, but are preferably linear alkoxy groups. The alkoxy group "not limited to 4 or more carbon atoms" preferably includes alkoxy groups having 1 to 18 carbon atoms, and in addition to the above alkoxy groups having 4 or more carbon atoms, alkoxy groups having 1 to 3 carbon atoms are mentioned.

Examples of alkyl groups include alkyl groups having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 6 carbon atoms. These may be linear, branched or alicyclic, but are preferably linear alkyl groups.

When at least one group of R ₁ to R ₃ is OH, the remaining groups are not particularly limited, but groups selected from OH, alkoxy groups and alkyl groups are preferred. In this case, the combinations of R ₁ to R ₃ are all OH (phosphoric acid), two OH and one alkoxy group (monoalkyl phosphate), one OH and two alkoxy groups (dialkyl phosphate). ), two OH and one alkyl group (monoalkylphosphonic acid), one OH and two alkyl groups (dialkylphosphinic acid), one OH and one alkoxy group and one alkyl group (monoalkylphosphinate ester).

When at least one group of R ₁ to R ₃ is an alkoxy group having 4 or more carbon atoms, the remaining groups are not particularly limited, but groups selected from OH, alkoxy groups and alkyl groups are preferred. The case where R ₁ to R ₃ contain OH corresponds to the case where the alkoxy group has 4 or more carbon atoms in the above combination. Combinations of R ₁ to R ₃ selected from alkoxy groups and alkyl groups include alkoxy groups all having 4 or more carbon atoms (trialkyl phosphate), two alkoxy groups having 4 or more carbon atoms and one alkyl group ( monoalkylphosphonic acid dialkyl ester), one alkoxy group having 4 or more carbon atoms and two alkyl groups (dialkylphosphinic acid monoalkyl ester). If the phosphorus compound contains multiple alkoxy groups, these are preferably the same for ease of availability. Therefore, when the compound needs to contain an "alkoxy group having 4 or more carbon atoms", the plurality of alkoxy groups are preferably the same "alkoxy group having 4 or more carbon atoms".

Phosphorus compounds having a plurality of phosphorus atoms include polyphosphoric acids such as diphosphoric acid, triphosphoric acid, cyclotriphosphoric acid, and tetraphosphoric acid, and ester compounds thereof (partially or wholly esterified compounds). mentioned. For fully esterified compounds, at least a portion, preferably all, of the alkoxy moieties of the ester are alkoxy groups having 4 or more carbon atoms. In the case of a partially esterified compound, the number of carbon atoms in the alkoxy moiety is not limited, but an alkoxy group having 4 or more carbon atoms is also preferable.

Phosphorus compounds containing multiple phosphorus atoms also include compounds with poly- or oligo-phosphate ester structures. Specifically, compounds represented by the general formula (PPE) can be mentioned.

In formula (PPE), R ₁ to R ₃ each independently represent a group selected from OH, an alkoxy group, H and an alkyl group, and _at least one of R ₁ to R ₃ One group represents OH or an alkoxy group having 4 or more carbon atoms. _R4 represents a divalent hydrocarbon group. n is an integer of 0 or more.

Preferred groups for R ₁ to R ₃ are the same as R ₁ to R ₃ shown for formula (P). Most preferably, all of R ₁ to R ₃ represent alkoxy groups having 4 or more carbon atoms. R ₄ is preferably a hydrocarbon group having 1 to 16 carbon atoms, more preferably 1 to 6 carbon atoms, and preferably a linear or branched alkylene group. n is preferably 0 to 4, more preferably 0 to 2, even more preferably 0.

In the present invention, it may be preferable that the molecular weight of the phosphorus compound is less than 400, and in particular the phosphorus compound represented by formula (P) and the phosphorus compound represented by formula (PPE) have a molecular weight of less than 400. is preferred.

Specific examples of phosphorus compounds include phosphoric acid, methylphosphonic acid, ethylphosphonic acid, n-propylphosphonic acid, isopropylphosphonic acid, n-butylphosphonic acid, sec-butylphosphonic acid, isobutylphosphonic acid and tert-butylphosphonic acid. acids, n-pentylphosphonic acid, isopentylphosphonic acid, neopentylphosphonic acid, n-hexylphosphonic acid, cyclohexylphosphonic acid, heptylphosphonic acid, n-octylphosphonic acid, nonylphosphonic acid, decylphosphonic acid, dodecylphosphonic acid, dodecylphosphonic acid, benzenephosphonic acid, (4-hydroxyphenyl)phosphonic acid, methylenediphosphonic acid, 1,2-ethylenediphosphonic acid, o-xylylenediphosphonic acid, m-xylylenediphosphonic acid, p-xylylenediphosphonic acid acid, dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, ethylbutylphosphinic acid, dipropylphosphinic acid, phenylphosphinic acid, diphenylphosphinic acid, methylphenylphosphinic acid, (2-carboxyethyl)phenylphosphinic acid, (2 -ethylhexyl) mono-2-ethylhexyl phosphate, tri-n-butyl phosphate, tri-n-pentyl phosphate, tri-n-hexyl phosphate, tris(2-ethylhexyl) phosphate, tris(2-butoxyethyl) phosphate , tris(1H,1H,5H-octafluoropentyl) phosphate, 2-ethylhexyldiphenyl phosphate, dibutyl phosphite (=dibutyl phosphonate), diisobutyl phosphite (=diisobutyl phosphonate), and the like. . In the above compounds, the alkyl group may be replaced with a structural isomer having the same number of carbon atoms, at least one H in the alkyl group or aryl group may be replaced with fluorine, and the substitution in the aryl group The position is arbitrary. Moreover, a phosphorus compound can be used individually or in combination of 2 or more types.

In one embodiment of the present invention, the polyimide precursor composition is such that when the phosphorus compound is phosphoric acid or tributyl phosphate, the polyimide precursor is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2 A polyimide precursor obtained only from "-norbornane-5,5",6,6"-tetracarboxylic dianhydride (CpODA), 4,4'-diaminobenzanilide (DABAN) and paraphenylenediamine (PPD) It may be preferred to differ from certain compositions, hi one embodiment of the invention, it may also be preferred that the polyimide precursor is selected from a combination of CpODA, DABAN and PPD and a different combination of monomers.

<Formulation of Polyimide Precursor Composition>
The polyimide precursor composition used in the present invention comprises at least one polyimide precursor, at least one phosphorus compound as described above, and a solvent.

The content of the phosphorus compound can be adjusted in consideration of the peel strength between the polyimide film and the substrate. In general, if the amount is too small, the peel strength is too high and peeling becomes difficult. It may become large (yellowness index b ^* increases), making it unsuitable for transparent applications.

The content of the phosphorus compound is preferably more than 0.001 mol %, more preferably more than 0.001 mol %, relative to the total monomer units of the polyimide precursor (i.e. formula (I), the repeating unit of formula (I) is counted as 2 mol) is 0.005 mol % or more, more preferably 0.01 mol % or more, still more preferably 0.02 mol % or more, still more preferably 0.05 mol % or more. Also, it is usually less than 5 mol %, more preferably 4 mol % or less, still more preferably 3 mol % or less, particularly preferably 2 mol % or less.

As the solvent, those mentioned above as the solvent used in preparing the polyimide precursor can be used. Generally, the solvent used in preparing the polyimide precursor can be used as it is, that is, as the polyimide precursor solution, but if necessary, it may be used after being diluted or concentrated. The phosphorus compound is present dissolved in the polyimide precursor composition.

The viscosity (rotational viscosity) of the polyimide precursor of the present invention is not particularly limited, but using an E-type rotational viscometer, the rotational viscosity measured at a temperature of 25 ° C. and a shear rate of 20 sec ⁻¹ is 0.01 to 1000 Pa · sec. is preferred, and 0.1 to 100 Pa·sec is more preferred. In addition, thixotropy can be imparted as necessary. When the viscosity is within the above range, handling is easy during coating or film formation, repelling is suppressed, and leveling is excellent, so that a good film can be obtained.

The polyimide precursor composition of the present invention contains, if necessary, a chemical imidizing agent (an acid anhydride such as acetic anhydride, an amine compound such as pyridine or isoquinoline), an antioxidant, an ultraviolet absorber, a filler (such as silica). inorganic particles, etc.), dyes, pigments, coupling agents such as silane coupling agents, primers, flame retardants, antifoaming agents, leveling agents, rheology control agents (fluidity aids), and the like.

The polyimide precursor composition can be prepared by adding and mixing a phosphorus compound or a solution of a phosphorus compound to the polyimide precursor solution obtained by the method described above. The tetracarboxylic acid component and the diamine component may be reacted in the presence of a phosphorus compound as long as it does not affect the reaction.

<<Manufacturing of polyimide/substrate laminate and flexible electronic device>>
The method for producing a flexible electronic device of the present invention comprises: (a) a step of applying a polyimide precursor composition on a substrate; (b) heat-treating the polyimide precursor on the substrate; (c) forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate. and (d) separating the base material and the polyimide film by an external force.

A polyimide precursor composition that can be used in the method of the present invention contains a polyimide precursor, a phosphorus compound and a solvent. As the phosphorus compound, those described in the section on the phosphorus compound can be used. As the polyimide precursor, those described in the section on the polyimide precursor composition can be used. Polyimide precursors described as being preferred in the polyimide precursor composition section are also preferred in the method of the present invention, but are not particularly limited.

In one embodiment of the method of the present invention, in step (a), the polyimide precursor composition contains phosphoric acid or tributyl phosphate as the phosphorus compound, the tetracarboxylic acid component consists of CpODA, and the diamine component consists of DABAN and A method using a precursor composition consisting of a mixture of PPDs and carrying out the production of the polyimide/substrate laminate in step (b) under heating conditions with a maximum temperature of 410° C., preferably 410° C. or higher. do not. Preferably, in the step (a), as the polyimide precursor composition, "precursor containing phosphoric acid or tributyl phosphate as a phosphorus compound, CpODA as a tetracarboxylic acid component, and a mixture of DABAN and PPD as a diamine component It does not include methods of using the composition.

First, in step (a), a polyimide precursor solution (including an imide solution with a high imidization rate and, if necessary, a composition solution containing additives) is cast on a substrate, and heat-treated to form an imide. A polyimide film is formed by desolvating and removing the solvent (mainly removing the solvent in the case of a polyimide solution) to obtain a laminate of the substrate and the polyimide film (polyimide/substrate laminate).

As the base material, a heat-resistant material is used. For example, a plate-like or A sheet-like base material, or a film or sheet-like base material such as a heat-resistant plastic material (such as polyimide) is used. In general, a flat and smooth plate shape is preferable, and glass substrates such as soda lime glass, borosilicate glass, alkali-free glass, and sapphire glass are generally used; semiconductor substrates such as silicon, GaAs, InP, and GaN (including compound semiconductors); Metal substrates such as iron, stainless steel, copper, and aluminum are used. In particular, glass substrates are preferred because flat, smooth, and large-area substrates have been developed and are readily available. These substrates may have an inorganic thin film (for example, a silicon oxide film) or a resin thin film formed on the surface.
Although the thickness of the plate-like substrate is not limited, it is, for example, 20 μm to 4 mm, preferably 100 μm to 2 mm, from the viewpoint of ease of handling.

The method of casting the polyimide precursor solution onto the base material is not particularly limited, and examples thereof include conventionally known methods such as spin coating, screen printing, bar coating, and electrodeposition.

In step (b), the polyimide precursor composition is heat treated on the substrate to convert it into a polyimide film to obtain a polyimide/substrate laminate. The heat treatment conditions are not particularly limited. For example, after drying in a temperature range of 50°C to 150°C, the maximum heating temperature is, for example, 150°C to 600°C, preferably 200°C to 550°C, more preferably 250°C. It is preferred to process at ~500°C. The heat treatment conditions when using a polyimide solution are not particularly limited, but the maximum heating temperature is, for example, 100° C. to 600° C., preferably 150° C. or higher, more preferably 200° C. or higher, and preferably 500° C. 450° C. or less, more preferably 450° C. or less.

The thickness of the polyimide film is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more. If the thickness is less than 1 μm, the polyimide film cannot maintain sufficient mechanical strength, and when used as a flexible electronic device substrate, for example, it may not withstand stress and break. Also, the thickness of the polyimide film is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 20 μm or less. When the thickness of the polyimide film increases, it may become difficult to reduce the thickness of the flexible device. The thickness of the polyimide film is preferably 2 to 50 μm in order to make it thinner while maintaining sufficient resistance as a flexible device.

In one embodiment, the polyimide film preferably has excellent optical properties such as 400 nm transmittance, total light transmittance (average transmittance at 380 nm to 780 nm), and yellowness b* (YI). The 400 nm light transmittance is preferably 50% or more, more preferably 70% or more, even more preferably 75% or more, and most preferably 80% or more, when each measured with a 10 μm thick film, and the total light transmittance is It is preferably 84% or more, more preferably 85% or more, and the yellowness b* (YI) is preferably 0 or more and 5 or less, more preferably 3 or less. Of 400 nm transmittance, total light transmittance and yellowness b*(YI), preferably at least one, more preferably at least two, and most preferably three simultaneously satisfy the preferred ranges.

In one embodiment, the polyimide film preferably has a small thickness direction retardation (retardation) _Rth . Moreover, in the polyimide precursor composition of the present invention, the addition of the phosphorus compound specified in the present invention hardly changes the _Rth of the resulting polyimide film. Therefore, in the present invention, the peel strength between the polyimide film and the substrate can be adjusted without affecting _Rth .

The obtained polyimide film is laminated in close contact with a base material such as a glass substrate. In order to facilitate mechanical peeling, the peel strength between the substrate and the polyimide film is preferably 0 when measured according to JIS K6854-1, for example, in a 90° peel test at a tensile speed of 2 mm/min. 0.8 N/in (N/25.4 mm) or less, more preferably 0.6 N/in or less, and even more preferably 0.4 N/in or less. On the other hand, the lower limit is preferably 0.01 N/in or more. Peel strength is usually measured in air or air.

The polyimide film in the polyimide/substrate laminate may have a second layer such as a resin film or an inorganic film on the surface. That is, after forming a polyimide film on a substrate, a second layer may be laminated to form a flexible electronic device substrate. It preferably has at least an inorganic film, and particularly preferably one that functions as a barrier layer against water vapor, oxygen (air), or the like. Examples of water vapor barrier layers include silicon nitride (SiN _x ), silicon oxide (SiO _x ), silicon oxynitride (SiO _x N _y ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and zirconium oxide. Inorganic films containing inorganic substances selected from the group consisting of metal oxides such as (ZrO ₂ ), metal nitrides and metal oxynitrides. In general, methods for forming these thin films include physical vapor deposition methods such as vacuum vapor deposition, sputtering, and ion plating, and chemical vapor deposition such as plasma CVD and catalytic chemical vapor deposition (Cat-CVD). method (chemical vapor deposition method) and the like are known. This second layer can also be multi-layered.

In the present invention, the polyimide precursor composition containing a phosphorus compound can reduce the peel strength. Accordingly, the present application provides a method for reducing the peel strength between a substrate and a polyimide film formed thereon in a laminate having a substrate and a polyimide film formed thereon, comprising: Also disclosed is an invention relating to a method for reducing the peel strength of a laminate, wherein the polyimide precursor composition of No. 1 contains the phosphorus compound described above.

In step (c), using the polyimide/substrate laminate obtained in step (c), on a polyimide film (including a second layer such as an inorganic film laminated on the surface of the polyimide film), At least one layer selected from a conductor layer and a semiconductor layer is formed. These layers may be formed directly on the polyimide film (including the lamination of the second layer) or may be formed indirectly on the lamination of the other layers required for the device. good.

As the conductor layer and/or the semiconductor layer, an appropriate conductor layer and (inorganic or organic) semiconductor layer are selected according to the elements and circuits required by the intended electronic device. When forming at least one of the conductor layer and the semiconductor layer in the step (c) of the present invention, it is also preferable to form at least one of the conductor layer and the semiconductor layer on the polyimide film on which the inorganic film is formed.

The conductor layer and the semiconductor layer include both those formed on the entire surface of the polyimide film and those formed on a part of the polyimide film. In the present invention, step (d) may be performed immediately after step (c), or after forming at least one layer selected from a conductor layer and a semiconductor layer in step (c), the device structure is further formed. After forming, the step (d) may be performed.

When manufacturing a TFT liquid crystal display device as a flexible device, for example, a metal wiring, a TFT made of amorphous silicon or polysilicon, and a transparent pixel electrode are formed on a polyimide film on which an inorganic film is formed on the entire surface if necessary. A TFT includes, for example, a gate metal layer, a semiconductor layer such as an amorphous silicon film, a gate insulating layer, wiring connected to a pixel electrode, and the like. On top of this, a structure necessary for a liquid crystal display can also be formed by a known method. Also, a transparent electrode and a color filter may be formed on the polyimide film.
When manufacturing an organic EL display, for example, a transparent electrode, a light-emitting layer, a hole-transporting layer, an electron-transporting layer, etc. are formed on a polyimide film on which an inorganic film is formed on the entire surface if necessary, and a TFT is formed as necessary. can do.

Since the polyimide film preferred in the present invention is excellent in various properties such as heat resistance and toughness, there are no particular restrictions on the method of forming the circuits, elements and other structures necessary for the device.

Next, in step (d), the base material and the polyimide film are physically separated by an external force. "By an external force" means applying a force so as to separate the substrate and the polyimide film. For example, it is peeled off manually or using an appropriate tool, jig, device, or the like. At the time of peeling, one or both of the base material and the polyimide film are bent. not in the range. For this purpose, a suitable tool, jig, device, or the like can be used for peeling so that the radius of curvature of the polyimide film is not reduced. Specifically, for example, (i) a method of peeling by inserting a tool such as a blade between the substrate and the polyimide film and moving it, (ii) a method of peeling the film by pulling it up from the substrate (at this time , a tool such as a blade may be used), and (iii) a method of curving and peeling the substrate while maintaining the flatness of the film as much as possible. Peeling is preferably performed in gas or vacuum, and usually in air or atmosphere.

A device is completed by forming or incorporating a structure or parts necessary for the device into a (semi-) product using the polyimide film after peeling off the base material as a substrate.

In a preferred embodiment of the present invention, the base material and the polyimide film are peeled off only by an external force peeling method without laser irradiation.

In a different embodiment of the present invention, the method of the present invention, i.e., the method of using a polyimide precursor containing a phosphorus compound, can be applied as an aid when laser irradiation alone does not achieve peeling.

Accordingly, a different aspect of the invention is
(a) a polyimide precursor composition containing a polyimide precursor, a phosphorus compound having a P (= O) OH structure or a P (= O) OR (wherein R is an alkyl group having 4 or more carbon atoms) structure and a solvent A step of applying onto the substrate,
(b) a step of heat-treating the polyimide precursor on the base material to produce a laminate in which a polyimide film is laminated on the base material;
(c) forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate;
(e) irradiating the laminate with a laser beam; and (d) separating the base material and the polyimide film by an external force.

A further different aspect of the invention relates to a method for enabling laser ablation in cases where laser irradiation ablation is not possible. Depending on the composition and / or for reasons such as insufficient laser output, when laser irradiation does not cause peeling, laser peeling is possible by using a polyimide precursor composition containing a phosphorus compound do. That is, this aspect
(a2) applying a polyimide precursor composition containing a polyimide precursor and a solvent onto a substrate;
(b2) a step of heat-treating the polyimide precursor on the base material to produce a laminate in which a polyimide film is laminated on the base material;
(c2) forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate; and (e2) irradiating the laminate with laser light. , wherein the polyimide precursor composition contains a phosphorus compound having a P (= O) OH structure or P (= O) OR (wherein R is an alkyl group having 4 or more carbon atoms) structure The present invention relates to a method for manufacturing flexible electronic devices.

The present invention will be further described below with reference to examples and comparative examples. In addition, the present invention is not limited to the following examples.

<Evaluation of polyimide film>
[b*(YI)]
Using a UV-visible spectrophotometer / V-650DS (manufactured by JASCO Corporation), ASTEM E313
b ^* (=YI; yellowness index) of a polyimide film having a film thickness of 10 μm and a size of 3 cm square was measured according to the standards of . The light source was D65 and the viewing angle was 2°.

[400 nm light transmittance, total light transmittance]
Using a UV-visible spectrophotometer / V-650DS (manufactured by JASCO Corporation), the light transmittance at a wavelength of 400 nm and the total light transmittance of a polyimide film having a thickness of 10 μm and a size of 5 cm square (average transmittance at wavelengths of 380 nm to 780 nm). was measured.

[Peel strength]
Using TENSILON RTA-500 manufactured by Orientec Co., Ltd., the peel strength in the 90° direction was measured under the condition of a tensile speed of 2 mm/min.

[Glass transition temperature (Tg)]
A polyimide film having a film thickness of about 10 μm was cut into a strip of 4 mm in width to obtain a test piece, and TMA/SS6100 (manufactured by SII Nanotechnology Co., Ltd.) was used, with a chuck length of 15 mm, a load of 2 g, and a heating rate of 20 ° C./ The temperature was raised to 500°C in minutes. The glass transition temperature (Tg) was calculated from the inflection point of the obtained TMA curve.

[1% weight loss temperature (Td1%)]
A polyimide film having a thickness of about 10 μm was used as a test piece, and the temperature was raised from 25° C. to 600° C. at a rate of 10° C./min in a nitrogen stream using a calorimeter (Q5000IR) manufactured by TA Instruments. A 1% weight loss temperature was obtained from the obtained weight curve.

The abbreviations of the compounds used in the examples below are as follows.
TFMB: 4,4'-bis(trifluoromethyl)benzidine ODA: 4,4'-diaminodiphenyl ether 4,4'-DDS: 4,4'-diaminodiphenylsulfone m-TD: 2,2'-dimethyl-4 ,4'-diaminobiphenyl BAFL: 9,9-bis(4-aminophenyl)fluorene BAPB: 4,4'-bis(4-aminophenoxy)biphenyl 6FDA: 4,4'-(2,2-hexafluoroiso Propylene)diphthalic dianhydride PMDA-HS: 1R,2S,4S,5R-cyclohexanetetracarboxylic dianhydride s-BPDA: 3,3′,4,4′-biphenyltetracarboxylic dianhydride BPADA: 5 ,5′-((propane 2-2-diylbis(1,4-phenylene))bis(oxy))bis(isobenzofuran-1,3-dione)
CpODA: norbornane-2-spiro-α-cyclopentanone-α'-spiro-2″-norbornane-5,5″,6,6″-tetracarboxylic dianhydride CBDA: cyclobutanetetracarboxylic dianhydride PPHT : N,N'-(1,4-phenylene)bis(1,3-dioxooctahydroisobenzofuran-5-carboxamide)

[Synthesis Example 1]
8.38 g (26.2 mmol) of TFMB was placed in a reaction vessel purged with nitrogen gas, and N-methyl-2-pyrrolidone was added so that the total mass of the charged monomers (the sum of the diamine component and the carboxylic acid component) was 20% by mass. A total of 80.03 g was added and stirred at room temperature for 30 minutes. To this solution was slowly added 11.62 g (26.2 mmol) of 6FDA. After stirring at room temperature for 12 hours, a uniform and viscous polyimide precursor solution was obtained.

[Synthesis Example 2]
8.02 g (40.0 mmol) of ODA was placed in a reaction vessel purged with nitrogen gas, and N,N-dimethylacetamide was added so that the total mass of the charged monomers (the sum of the diamine component and the carboxylic acid component) was 17% by mass. of 83.04 g was added and stirred at room temperature for 30 minutes. 8.98 g (40.0 mmol) of PMDA-HS was slowly added to this solution. After stirring at room temperature for 12 hours, a uniform and viscous polyimide precursor solution was obtained.

[Synthesis Example 3]
6.68 g (20.8 mmol) of TFMB was placed in a reaction vessel purged with nitrogen gas, and N-methyl-2-pyrrolidone was added so that the total mass of the charged monomers (the sum of the diamine component and the carboxylic acid component) was 20% by mass. A total of 59.99 g was added and stirred at room temperature for 30 minutes. 6FDA 6.48 g (14.6 mmol) and s-BPDA 1.85 g (6.3 mmol) were gradually added to this solution. After stirring at room temperature for 12 hours, a uniform and viscous polyimide precursor solution was obtained.

[Synthesis Example 4]
10.20 g (31.9 mmol) of TFMB and 0.16 g (0.6 mmol) of 4,4′-DDS were placed in a reaction vessel purged with nitrogen gas, and N,N-dimethylacetamide was added to the total mass of the charged monomers. 80.02 g was added in an amount such that (the sum of the diamine component and the carboxylic acid component) was 20% by mass, and the mixture was stirred at room temperature for 30 minutes. 0.17 g (0.3 mmol) of BPADA and 9.47 g (32.2 mmol) of s-BPDA were slowly added to this solution. After stirring at room temperature for 12 hours, a uniform and viscous polyimide precursor solution was obtained.

[Synthesis Example 5]
10.93 g (51.5 mmol) of m-TD was placed in a reaction vessel purged with nitrogen gas, and N-methyl-2-pyrrolidone was added. % was added and stirred at room temperature for 30 minutes. 1.98 g (5.1 mmol) of CpODA and 9.88 g (46.3 mmol) of CBDA were gradually added to this solution. After stirring at room temperature for 12 hours, a uniform and viscous polyimide precursor solution was obtained.

[Synthesis Example 6]
13.55 g (38.9 mmol) of BAFL and 33.44 g (90.8 mmol) of BAPB are placed in a reaction vessel purged with nitrogen gas, and N-methyl-2-pyrrolidone is added to the total mass of charged monomers (diamine component and 395.02 g was added in such an amount that the sum of carboxylic acid components) was 21% by mass, and the mixture was stirred at room temperature for 30 minutes. 12.46 g (32.4 mmol) of CpODA and 45.55 g (97.2 mmol) of PPHT were gradually added to this solution. After stirring at room temperature for 12 hours, a uniform and viscous polyimide precursor solution was obtained.

[Example 1]
1.6 mg (0.017 mmol) of methylphosphonic acid and 0.56 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 30.17 g of the polyamic acid solution obtained in Synthesis Example 1 (the total amount of monomers in the polyamic acid solution is 15.8 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers was 0.11 mol %.

This polyamic acid solution was applied onto the substrate glass plate by a spin coater, and the coating film was heated from 30°C to 350°C at a temperature elevation rate of 3°C/min in a nitrogen atmosphere. A polyimide film having a thickness of 10 μm was formed on the glass plate. The peel strength was measured by making a 1 inch (25.4 mm) wide test sample from the resulting polyimide film/glass laminate. For the tensile test, after the obtained polyimide film/glass laminate was immersed in water, the polyimide film was peeled off from the glass plate, dried, cut into a predetermined size to prepare a test sample, and the properties were measured. did Also in the following examples, tensile test samples were prepared and measured in the same manner. The optical properties were measured by mechanically peeling off the polyimide film from the polyimide film/glass laminate and cutting it into a predetermined size to prepare a test sample. The same applies to the following examples, but for comparative examples in which peel strength is high and mechanical peeling is not possible, measurement samples were prepared in the same manner as the preparation of tensile test samples. The results are shown in the table.

[Example 2]
2.2 mg (0.023 mmol) of methylphosphonic acid and 0.53 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a homogeneous solution. 30.00 g of the polyamic acid solution obtained in Synthesis Example 2 (the total amount of monomers in the polyamic acid solution is 24.0 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.10 mol %.
This polyamic acid solution was applied onto the substrate glass plate by a spin coater, and the coating film was heated from 30°C to 350°C at a temperature elevation rate of 3°C/min in a nitrogen atmosphere. A polyimide film having a thickness of 10 μm was formed on the glass plate. The obtained film was peeled off from the glass plate, and various properties were measured.

[Example 3]
1.6 mg (0.017 mmol) of methylphosphonic acid and 0.53 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 30.02 g of the polyamic acid solution obtained in Synthesis Example 3 (the total amount of monomers in the polyamic acid solution is 16.7 millimoles) was added to the solution and stirred at room temperature for 12 hours to form a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.10 mol %.

This polyamic acid solution was applied onto the substrate glass plate by a spin coater, and the coating film was heated from 30°C to 350°C at a temperature elevation rate of 3°C/min in a nitrogen atmosphere. A polyimide film having a thickness of 10 μm was formed on the glass plate. The obtained film was peeled off from the glass plate, and various properties were measured.

[Example 4]
To 1.9 mg (0.020 mmol) of methylphosphonic acid was added 29.99 g of the polyamic acid solution obtained in Synthesis Example 4 (the total amount of monomers in the polyamic acid solution was 20.8 mmol), and the mixture was stirred at room temperature for 12 hours to obtain a uniform mixture. to obtain a viscous polyimide precursor solution. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.10 mol %.

This polyamic acid solution was applied onto a glass plate as a substrate by a spin coater, and the coating film was heated from 30° C. to 70° C. at a heating rate of 2.5° C./min in a nitrogen atmosphere. C. for 20 minutes, then heated from 70.degree. C. to 120.degree. C. at a temperature increase rate of 2.5.degree. The temperature was raised from 120° C. to 300° C. using a pressure cooker, and heat treatment was performed at 300° C. for 5 minutes to form a polyimide film having a thickness of 10 μm on the glass plate. The obtained film was peeled off from the glass plate, and various properties were measured.

[Example 5]
To 3.1 mg (0.032 mmol) of methylphosphonic acid was added 30.03 g of the polyamic acid solution obtained in Synthesis Example 5 (the total amount of monomers in the polyamic acid solution was 30.9 mmol), and the mixture was stirred at room temperature for 12 hours to form a uniform mixture. to obtain a viscous polyimide precursor solution. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.10 mol %.

This polyamic acid solution was applied onto the substrate glass plate by a spin coater, and the coating film was heated from 30°C to 80°C at a temperature elevation rate of 3°C/min in a nitrogen atmosphere. Then, the temperature was raised from 80° C. to 260° C. at a heating rate of 3° C./min and heat-treated at 260° C. for 10 minutes to form a polyimide film having a thickness of 10 μm on the glass plate. The obtained film was peeled off from the glass plate, and various properties were measured.

[Example 6]
1.9 mg (0.020 mmol) of methylphosphonic acid and 0.60 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 40.02 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 20.8 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.10 mol %.

This polyamic acid solution was applied onto a glass plate as a base material by a spin coater, and the coating film was heated from 30°C to 310°C at a heating rate of 5°C/min in a nitrogen atmosphere, and then to 310°C. A polyimide film having a thickness of 10 μm was formed on the glass plate by heating for 20 minutes. The obtained film was peeled off from the glass plate, and various properties were measured.

[Comparative Example 1]
A polyimide film was formed in the same manner as in Example 6 except that the polyamic acid solution obtained in Synthesis Example 6 was used as it was, and various properties were measured. However, as for the peel test, although an attempt was made to prepare a test sample, the adhesive force between the glass plate and the polyimide film was too large to form a gripping portion for the film, so the measurement could not be performed.

[Comparative Example 2]
10 mg (0.10 mmol) of methylphosphonic acid and 10.02 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. To 14.5 mg of this solution was added 30.00 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution was 15.6 mmol), and the mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor. Body solution was obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.001 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various properties were measured.

[Example 7]
10 mg (0.10 mmol) of methylphosphonic acid and 10.01 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. To 149.9 mg of this solution was added 29.98 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution was 15.5 mmol), and the mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor. Body solution was obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.01 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Example 8]
49.9 mg (0.52 mmol) of methylphosphonic acid and 5.07 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a homogeneous solution. To 50.2 mg of this solution was added 20.01 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution was 10.4 mmol), and the mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor. Body solution was obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.05 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Example 9]
7.7 mg (0.080 mmol) of methylphosphonic acid and 0.52 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 30.14 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 15.6 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 0.5 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Example 10]
12.0 mg (0.13 mmol) of methylphosphonic acid and 0.50 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 20.16 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 10.5 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 1.2 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Comparative Example 3]
49.8 mg (0.52 mmol) of methylphosphonic acid and 0.50 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a homogeneous solution. 20.03 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 10.4 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of methylphosphonic acid to the total amount of polyimide monomers is 5.0 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured. However, the peel strength between the glass plate and the polyimide film was too small, and the film spontaneously peeled off during preparation of the peel test sample.

[Example 11]
2.4 mg (0.021 mmol) of phosphoric acid and 0.60 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 43.29 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 22.4 mmol) was added to the solution, and the mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of phosphoric acid to the total amount of polyimide monomers is 0.09 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Example 12]
9.2 mg (0.080 mmol) of phosphoric acid and 0.51 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 30.00 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 15.6 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of phosphoric acid to the total amount of polyimide monomers is 0.51 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Example 13]
12.2 mg (0.106 mmol) of phosphoric acid and 0.53 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 19.99 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 10.4 mmol) was added to the solution and stirred at room temperature for 12 hours to form a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of phosphoric acid to the total amount of polyimide monomers is 1.0 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Example 14]
4.5 mg (0.017 mmol) of tributyl phosphate and 0.60 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 35.96 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 18.6 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of tributyl phosphate to the total amount of polyimide monomers is 0.09 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Example 15]
32.7 mg (0.123 mmol) of tributyl phosphate and 0.50 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 20.06 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 10.4 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of tributyl phosphate to the total amount of polyimide monomers is 1.2 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Example 16]
4.4 mg (0.0201 mmol) of diphenylphosphinic acid and 0.61 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 40.11 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 20.8 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of diphenylphosphinic acid to the total amount of polyimide monomers is 0.10 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Comparative Example 4]
3.5 mg (0.023 mmol) of diethyl methylphosphonate and 0.61 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 40.06 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 20.8 mmol) was added to the solution and stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution. Obtained. Calculated from the charged amount, the ratio of diethyl methylphosphonate to the total amount of polyimide monomers is 0.11 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Comparative Example 5]
4.6 mg (0.021 mmol) of tributylphosphine oxide and 0.79 g of N-methyl-2-pyrrolidone were added to the reactor to obtain a homogeneous solution. 39.97 g of the polyamic acid solution obtained in Synthesis Example 6 (the total amount of monomers in the polyamic acid solution is 20.7 millimoles) was added to the solution and stirred at room temperature for 12 hours to form a uniform and viscous polyimide precursor solution. Obtained. Calculating from the charged amount, the ratio of tributylphosphine oxide to the total amount of polyimide monomers was 0.10 mol %. A polyimide film was formed in the same manner as in Example 6 except that this polyamic acid solution was used, and various characteristics were measured.

[Comparative Examples 6 to 9]
Polyimide films were formed in the same manner as in Example 6 except that the polyamic acid solutions obtained in Synthesis Examples 1 to 3 and 5 were used as they were, and various properties were measured.

Tables 3 to 7 show the compositions of Examples and Comparative Examples, and the measurement results of b ^* , peeling properties, and 400 nm transmittance for the films obtained. 10.

INDUSTRIAL APPLICABILITY The present invention can be suitably applied to the manufacture of flexible electronic devices, for example, display devices such as liquid crystal displays, organic EL displays and electronic papers, and light receiving devices such as solar cells and CMOS.

Claims (14)

polyimide precursor,
Phosphoric acid, a monoalkylphosphonic acid having two OH and one alkyl group attached to the phosphorus atom, in an amount greater than 0.001 mol % and less than 5 mol % relative to the total monomer units of the polyimide precursor; Dialkylphosphinic acids with one OH and two alkyl groups bonded to the phosphorus atom, monoalkylphosphinic acid alkyl esters with one OH, one alkoxy group and one alkyl group bonded to the phosphorus atom, the phosphorus atom monoalkyl phosphonic acid dialkyl ester in which two alkoxy groups having 4 or more carbon atoms and one alkyl group are bonded to the phosphorus atom, and one alkoxy group having 4 or more carbon atoms and two alkyl groups are bonded to the phosphorus atom A polyimide precursor composition comprising a phosphorus compound selected from the group consisting of dialkylphosphinic acid monoalkyl esters , and a solvent, provided that the following condition (A) is satisfied.
(A) The polyimide precursor is not a polyimide precursor obtained only from 3,3′,4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine. 2. The composition according to claim 1, wherein the phosphorus compound content is in an amount of 0.01 mol % or more relative to the total monomer units of the polyimide precursor. 3. The composition of claim 1 or 2 , wherein the phosphorus compound has a molecular weight of less than 400. The polyimide precursor comprises a repeating unit selected from the structure represented by the following general formula (I) and a structure in which at least one of the amide structures in the general formula (I) is imidized. 4. The composition according to any one of 1 to 3 .

(In general formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, R ₁ and R ₂ are independently hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.) X ₁ is a tetravalent group having an alicyclic structure, and Y ₁ is a divalent group having an alicyclic structure. 50 mol % or less of the composition according to claim 4 . 5. The composition according to claim 4 , wherein _X1 in general formula (I) is a tetravalent group having an aromatic ring, and _Y1 is a divalent group having an aromatic ring. 5. The composition according to claim 4 , wherein _X1 in general formula (I) is a tetravalent group having an alicyclic structure, and _Y1 is a divalent group having an aromatic ring. 5. The composition according to claim 4 , wherein _X1 in general formula (I) is a tetravalent group having an aromatic ring, and _Y1 is a divalent group having an alicyclic structure. X ₁ of the general formula (I) contains a repeating unit that is a tetravalent group having an alicyclic structure at a rate of more than 60% in all repeating units (provided that X ₁ is a tetravalent group having an alicyclic structure and Y ₁ is a divalent group having an alicyclic structure. 5. The composition of claim 4 , characterized in that. (a) applying the polyimide precursor composition according to any one of claims 1 to 9 onto a substrate;
(b) a step of heat-treating the polyimide precursor on the base material to produce a laminate in which a polyimide film is laminated on the base material;
(c) forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate; and (d) separating the base material and the polyimide film by an external force. A method of manufacturing a flexible electronic device comprising: The manufacturing method according to claim 10 , wherein the substrate is a glass plate. 12. The manufacturing method according to claim 10 , wherein laser irradiation is not performed in the step of separating the base material and the polyimide film. A method for reducing the peel strength between a substrate and a polyimide film of a laminate having a substrate and a polyimide film formed on the substrate, comprising:
Peel strength of the laminate, characterized in that the polyimide precursor composition for forming the polyimide film contains a phosphorus compound so as to become the polyimide precursor according to any one of claims 1 to 9. Lowering method. 14. The method of claim 13 , wherein the substrate is a glass plate.