WO2021193978A1

WO2021193978A1 - Polyimide precursor composition and polyimide film/substrate laminate

Info

Publication number: WO2021193978A1
Application number: PCT/JP2021/013323
Authority: WO
Inventors: 卓也岡; 幸徳小濱
Original assignee: 宇部興産株式会社
Priority date: 2020-03-27
Filing date: 2021-03-29
Publication date: 2021-09-30
Also published as: TW202142599A; JPWO2021193978A1; TWI781563B; JP7400948B2; CN115551949A; KR20220158783A; CN115551949B

Abstract

Provided is a polyimide precursor composition that has excellent stability and that enables production of a polyimide film/substrate laminate having less warpage. The polyimide precursor composition contains: a polyimide precursor; a phenyl group-containing linear siloxane compound that has a refractive index of 1.54 or greater and that is contained in an amount more than 0.5 parts by mass but less than 30 parts by mass with respect to 100 parts by mass expressed in terms of polyimides of the polyimide precursor; and a solvent.

Description

Polyimide precursor composition and polyimide film / base material laminate

The present invention relates to a polyimide precursor composition preferably used for electronic device applications such as a substrate of a flexible device, and a polyimide film / base material laminate with reduced warpage. In addition, the present invention relates to a method for manufacturing a flexible electronic device using the composition.

Polyimide film has been widely used in fields such as electrical / electronic device fields and semiconductor fields because it has excellent heat resistance, chemical resistance, mechanical strength, electrical characteristics, and dimensional stability. On the other hand, in recent years, with the advent of the advanced information society, the development of optical materials such as optical fibers and optical waveguides in the field of optical communication, liquid crystal alignment films in the field of display devices, and protective films for color filters has been progressing. Especially in the field of display devices, a lightweight and highly flexible plastic substrate is being studied as an alternative to a glass substrate, and a display that can be bent or rolled is being actively developed.

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

Since polyimide is generally colored yellowish brown, its use in transmissive devices such as liquid crystal displays equipped with a backlight has been restricted, but in recent years, in addition to mechanical and thermal properties, it has been limited. A polyimide film having excellent transparency has been developed, and expectations are further increasing 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, etc. on the flexible film. For example, Patent Document 4 states, "A step of applying 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, and the circuit. Describes a method for manufacturing a flexible device, which is a display device or a light receiving device, including each step of peeling a solid resin film formed on the surface of the carrier substrate from the carrier substrate.

Further, in Patent Document 5, as a method for 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 including irradiating a laser from the glass substrate side to peel off the glass substrate is disclosed.

International Publication No. 2012/011590 International Publication No. 2013/179727 International Publication No. 2014/038715 JP-A-2010-202729 International Publication No. 2018/221607 International Publication No. 2014/098235 JP-A-2019-203117

When the methods of Patent Documents 4 and 5 are applied to actual production, the polyimide film / glass base material laminate is warped, which makes it difficult to form the element accurately and deteriorates the handleability. In some cases. In particular, when a large glass substrate is used, as a specific example, it is applied to a so-called multi-chamfering method for manufacturing a large flexible electronic device (for example, a large display device) or a plurality of flexible electronic devices (for example, a display device) from one substrate. In that case, the warp may expand to a non-negligible degree.

Patent Document 6 describes an inorganic film and a support by a polyimide precursor in which a silicone structure (polysiloxane structure) is introduced into a skeleton by using a silicone diamine together with 2,2-bis (trifluoromethyl) benzidine as a diamine component. It is disclosed that the residual stress between the substrate and the polyimide film can be reduced. However, since the structure of polyimide is limited, it lacks versatility and may not obtain the desired physical properties. Further, it has been pointed out that the reactive group portion is easily degassed and the amount of degassing during heating is increased (Patent Document 7 0008).

Patent Document 7 describes a specific linear shape having a specific cyclic polysiloxane compound or a silanol group, a hydrolyzable alkoxysilyl group, or the like at the terminal with respect to 100 parts by mass of the polyimide precursor and a solvent. It is disclosed that the residual stress generated at the interface between the polyimide film and the glass substrate can be reduced by using the polyimide precursor resin composition containing 0.01 to 0.5 parts by mass of the polysiloxane compound.

However, the specific cyclic siloxane compound and the specific linear siloxane compound described in Patent Document 7 have a small stress relaxation effect. For example, when a small amount of the compound is added, the stress relaxation effect is almost nonexistent, and when a large amount is added. Remains in the polyimide film and is released at the time of reheating, so that there is a problem that the apparatus is contaminated at the time of forming the barrier membrane, the element and the like.

The present invention has been made in view of the conventional problems, and a main object thereof is a polyimide precursor composition capable of producing a polyimide film / base material laminate having a small warpage and excellent stability. To provide things. Further, an object of one aspect of the present invention is to provide a polyimide film obtained by using the polyimide precursor composition and a polyimide film / base material laminate, and further, an object of another aspect of the present invention is. , A method for producing a flexible electronic device using the polyimide precursor composition, and a flexible electronic device.

The main disclosure items of this application are summarized below.

1. 1. Polyimide precursors (provided that the polyimide precursors are not imidized or are partially or completely imidized),
Contains a phenyl group-containing linear siloxane compound having a refractive index of 1.54 or more in an amount of more than 0.5 parts by mass to less than 30 parts by mass with respect to 100 parts by mass of the polyimide precursor in terms of polyimide, and a solvent. A polyimide precursor composition comprising.

2. Item 2. The composition according to Item 1, wherein the siloxane compound does not have a silanol group and a group that hydrolyzes to become a silanol group.

3. Item 2. The composition according to Item 1 or 2, wherein the phenyl group is bonded to the terminal Si.

4. Polyimide precursors (provided that the polyimide precursors are not imidized or are partially or completely imidized),
Contains a phenyl group-containing linear siloxane compound represented by the following formula (S) and a solvent in an amount of more than 0.5 parts by mass to less than 30 parts by mass with respect to 100 parts by mass of the polyimide precursor in terms of polyimide. A polyimide precursor composition comprising.

(In the formula, n is an integer of 0 to 50, preferably 0 to 10, and R ₁ to R ₈ are independent of each other, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an aryl having 6 to 15 carbon atoms. Selected from the groups, when n is 2 or more, R ₄ and R ₅ may each represent different groups in multiple occurrences, and _{at least one of R 1} to R ₈ represents a phenyl group).
In particular, the phenyl group-containing linear siloxane compound having a refractive index of 1.54 or more in the above item 1 is at least one selected from the phenyl group-containing linear siloxane compound represented by the above formula (S). Is preferable.

5. Item 4. The composition according to Item 4, wherein _{one or more of R 1} to R ₃ is a phenyl group and one or more of R ₆ to R _{8 is a phenyl group.}

6. The above-mentioned item, wherein the polyimide precursor contains 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 to 5.

(In the general formula I, X ₁ is a tetravalent aliphatic group or an aromatic group, Y ₁ is a divalent aliphatic group or an aromatic group, and R ₁ and R ₂ are independent of each other and hydrogen. Atomic, an alkyl group having 1 to 6 carbon atoms or an alkylsilyl group having 3 to 9 carbon atoms.)

7. The content of the repeating unit represented by the general formula (I), in which X ₁ is a tetravalent group having an alicyclic structure and Y _{1 is a divalent group having an alicyclic structure, is based on all the repeating units.} The composition according to Item 6, wherein the composition is 50 mol% or less.

8. Item 6. The composition according to Item 6, _{wherein X 1} in the general formula (I) is a tetravalent group having an aromatic ring, and Y _{1 is a divalent group having an aromatic ring.}

9. Item 6. The composition according to Item 6, wherein _{X 1} in the general formula (I) is a tetravalent group having an alicyclic structure, and Y _{1 is a divalent group having an aromatic ring.}

10. Item 6. The composition according to Item 6, _{wherein X 1} in the general formula (I) is a tetravalent group having an aromatic ring, and Y _{1 is a divalent group having an alicyclic structure.}

11. The X ₁ of the general formula (I) contains 60 percent proportion of the total repeating units of repeating units is a tetravalent group having an alicyclic structure (however, tetravalent X ₁ has an alicyclic structure The content of the repeating unit represented by the general formula (I), which is a group of the above and Y ₁ is a divalent group having an alicyclic structure, is 50 mol% or less with respect to all the repeating units). The composition according to item 6 above.

12. _{Y 1} of the general formula (I) is the following formula (4):

{In formula (4), n ₁₁ to n ₁₃ independently represent integers of 0 to 4, and R ₅₁ , R ₅₂ , and R ₅₃ independently represent alkyl groups and halogen groups having 1 to 6 carbon atoms, respectively. It is a hydroxyl group, a carboxyl group, or a trifluoromethyl group, and W ₁ is a direct bond, -CO-, -NHCO-, -CONH-, -COO-, -OCO-, or the formula (6) :.

(R ₆₁ to R ₆₈ are direct bonds, -CO-, -NHCO-, -CONH-, -COO- or -OCO-.)}
Based on composition according to Item 6, characterized in that it comprises an amount of more than 60 mol% relative to the total Y ₁ represented in.

13. A polyimide film obtained from the polyimide precursor composition according to any one of the above items 1 to 12.

14. A polyimide film obtained from the polyimide precursor composition according to any one of the above items 1 to 12, and a polyimide film.
A polyimide film / base material laminate characterized by having a base material.

15. Item 2. The laminate according to Item 14, wherein the base material is a glass substrate.

16. (A) The step of applying the polyimide precursor composition according to any one of the above items 1 to 12 onto a base material, and (b) the polyimide precursor being heat-treated on the base material to obtain the above. A method for producing a polyimide film / substrate laminate, which comprises a step of laminating a polyimide film on a substrate.

17. Item 16. The manufacturing method according to Item 16, wherein the base material is a glass substrate.

18. (A) A step of applying the polyimide precursor composition according to any one of the above items 1 to 12 onto a substrate.
(B) A step of heat-treating the polyimide precursor on the base material to produce a polyimide film / base material laminate in which the polyimide film is laminated on the base material.
Flexible electrons having (c) a step of forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminated body, and (d) a step of peeling the base material and the polyimide film. How to make the device.

19. Item 8. The manufacturing method according to Item 18, wherein the base material is a glass plate.

According to the present invention, it is possible to produce a polyimide film / base material laminate having a small warp, and to provide a polyimide precursor composition having excellent stability. According to the embodiment of the polyimide precursor composition of the present invention, in addition to the effect that (i) a polyimide film / glass substrate laminate having a small warp can be produced, (ii) the obtained polyimide film can be obtained. One or more of the effects of excellent transparency, (iii) the obtained polyimide film has excellent mechanical properties such as elongation at break, and (iv) excellent stability (eg, evaluated by uniformity, viscosity change, etc.). In a preferred embodiment, all of the effects of (ii) to (iv) are exhibited in addition to the effect of (i).

Further, according to one aspect of the present invention, it is possible to provide a polyimide film obtained by using the polyimide precursor composition and a polyimide film / base material laminate. Further, according to another aspect of the present invention, it is possible to provide a method for producing a flexible electronic device using the polyimide precursor composition, and a flexible electronic device.

It is a figure which shows typically the warp of the polyimide film / base material laminate. It is a figure for demonstrating the method of determining the residual stress of a polyimide film / reference base material laminate.

In the present application, "flexible (electronic) device" means that the device itself is flexible, and usually, a semiconductor layer (transistor, diode, etc. as an element) is formed on a substrate to complete the device. 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 wiring board). However, in order to operate or control the "flexible (electronic) device" of the present application, a "hard" semiconductor element such as an IC chip is mounted on a flexible substrate or electrically connected to be fused and used. There is nothing wrong with doing it. Flexible (electronic) devices that are preferably used include liquid crystal displays, organic EL displays, display devices such as electronic paper, solar cells, and light receiving devices such as CMOS.

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

<< Polyimide precursor composition >>
The polyimide precursor composition for forming the polyimide film contains a polyimide precursor, a specific siloxane compound and a solvent. Both the polyimide precursor and the particular siloxane compound are dissolved in the solvent.
In the present 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" refers to polyamic acids and derivatives (precisely defined by formula (I)), partially imidized polyamic acids and derivatives that have been partially imidized, polyimides, and mixtures thereof. including. That is, the polyimide precursor is not imidized, or is partially or completely imidized. Therefore, in the present application, the term "polyimide precursor" includes all ranges from 0% to 100% imidization rate. However, all of the polyimide precursor compositions are dissolved in a solvent.

An example of the polyimide precursor is the following general formula (I):

(In the general formula I, X ₁ is a tetravalent aliphatic group or an aromatic group, Y ₁ is a divalent aliphatic group or an aromatic group, and R ₁ and R ₂ are independent of each other and hydrogen. Atomic, 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 is a polyamic acid in which _{R 1} and R _{2 are hydrogen atoms.}

A different example of the polyimide precursor is a polyimide precursor that has been partially or completely imidized, and at least one of the two amide structures (-CONH-) in the general formula (I) is -COOR _1. Includes repeating units that have been imidized by reacting with and / or -COOR _2.

The polyimide formed from the polyimide precursor having the repeating unit represented by the general formula (I) is the following general formula (II):

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

Below, the chemical structure of such polyimide, the repeating unit (formula (I) and (II)) X ₁ and Y ₂ of the structure and the monomers used in the preparation (tetracarboxylic acid component in the diamine component , Other components), followed by a description of the manufacturing method.

In the present specification, the tetracarboxylic acid component is tetracarboxylic acid, tetracarboxylic acid dianhydride, other tetracarboxylic acid silyl ester, tetracarboxylic acid ester, tetracarboxylic acid chloride and the like used as a raw material for producing polyimide. Contains carboxylic acid derivatives. Although not particularly limited, it is convenient to use tetracarboxylic dianhydride in production, and the following description describes an example in which tetracarboxylic dianhydride is used as the tetracarboxylic acid component. The diamine component is a diamine compound having _two amino groups (-NH 2), which is used as a raw material for producing polyimide.

Further, in the present specification, the polyimide film means both a film formed on a (carrier) base material and existing in a laminate, and a film after the base material is peeled off. Further, the material constituting the polyimide film, that is, the material obtained by heat-treating (imidizing) the polyimide precursor composition may be referred to as "polyimide material".

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

Although not particularly limited, since the obtained 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. It is preferably a divalent group. Further, since the obtained polyimide material has excellent heat resistance and transparency, X ₁ is a tetravalent group having an alicyclic structure, and Y ₁ is a divalent group having an aromatic ring. preferable. Further, since the obtained polyimide material has excellent heat resistance and dimensional stability, X ₁ is a tetravalent group having an aromatic ring and Y ₁ is a divalent group having an alicyclic structure. Is preferable.

From the viewpoint of the properties of the obtained polyimide material, for example, transparency, mechanical properties, heat resistance, etc., 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 the basic formula (I) is preferably 50 mol% or less, more preferably 30 mol% or less or less than 30 mol%, more preferably 10 mol, based on all the repeating units. % Or less is preferable.

In certain embodiments, the content of one or more of the repeating units of 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, in total, with respect to all repeating units, 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%. It is preferable to have. In this embodiment, especially when a highly transparent polyimide material is required, the polyimide preferably contains a fluorine atom. That is, the polyimide is a _{tetravalent group in which X 1} has an aromatic ring containing a fluorine atom, and / or Y ₁ has an aromatic ring containing a fluorine atom. It is preferable to include one or more of the repeating units of the general formula (I) which is the basis of the valence.

In certain embodiments, the polyimide precursor is a repeating unit of 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 one or more 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, relative to all repeating units. It is preferably 100 mol%.

In certain embodiments, the polyimide precursor is _one of the repeating units of 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 the seeds or more 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 the repeating units. Is preferably 100 mol%.

Among them, in the polyimide precursor contained in the polyimide precursor composition of the present invention, X ₁ is a tetravalent group having an alicyclic structure and Y ₁ is a divalent group having an aromatic ring. The repeating unit (a) of the general formula (I) and the repeating unit of the above formula (I) in which X ₁ is a tetravalent group having an aromatic ring and Y ₁ is a divalent group having an alicyclic structure. It is preferable to contain at least one selected from the group consisting of (b), and in particular, X ₁ is a tetravalent group having an alicyclic structure and Y ₁ is a divalent group having an aromatic ring. It preferably contains the repeating unit (a) of the formula (I). In this case, the ratio of the repeating unit (a) or the repeating unit (b) is preferably 50 mol% or more, more preferably 70 mol% or more, and more preferably 80 mol% with respect to all the repeating units, as described above. The above is more preferably 90 mol% or more, and particularly preferably 100 mol%.

<X ₁ and tetracarboxylic acid component>
As the _{tetravalent group having an aromatic ring of X 1} , a tetravalent group having an aromatic ring having 6 to 40 carbon atoms is preferable.

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

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

Is one of. However, Z ₂ in the formula is a divalent organic group, Z _{3 and} Z ₄ are independently amide bonds, ester bonds and carbonyl bonds, respectively, and Z ₅ is an organic group containing an aromatic ring. )

Specific examples of Z ₂ include an aliphatic hydrocarbon group having 2 to 24 carbon atoms and an aromatic hydrocarbon group having 6 to 24 carbon atoms.

Specific examples of Z ₅ include aromatic hydrocarbon groups having 6 to 24 carbon atoms.

As the tetravalent group having an aromatic ring, the following is particularly preferable because it can achieve both high heat resistance and high transparency of the obtained polyimide film.

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

Here, it is more preferable that _{Z 1} 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 preferable group, in the above formula (9), Z ₁ is the following formula (3A):

Examples thereof include compounds which are fluorenyl-containing groups represented by. Z ₁₁ and Z ₁₂ are independent, preferably identical, single-bonded or divalent organic groups, respectively. As Z ₁₁ and Z ₁₂ , organic groups containing an aromatic ring are preferable, and for example, the formula (3A1):

(Z ₁₃ and Z ₁₄ are single bonds independently of each other, -COO-, -OCO- or -O-, where if Z ₁₄ is attached to a fluorenyl group, then Z ₁₃ is -COO-, -OCO-. Alternatively, _{a structure in which Z 14} is a single bond in _{—O— is preferable; R 91} is an alkyl group or a phenyl group having 1 to 4 carbon atoms, preferably methyl, and n is an integer of 0 to 4, preferably an integer of 0 to 4. It is 1.)
The structure represented by is preferable.

Examples of the tetracarboxylic acid component that gives the repeating unit of the 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-dioxo tetrahydrofuran-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 Examples thereof include carboxyphenoxydiphenyl sulfide, sulfonyldiphthalic acid, and derivatives such as tetracarboxylic acid dianhydride, tetracarboxylic acid silyl ester, tetracarboxylic acid ester, and tetracarboxylic acid chloride. Examples of the tetracarboxylic acid component that gives the repeating unit of the general formula (I) in which X ₁ is a tetravalent group having an aromatic ring containing a fluorine atom include 2,2-bis (3,4-dicarboxy). Examples thereof include phenyl) hexafluoropropane and derivatives thereof such as tetracarboxylic acid dianhydride, tetracarboxylic acid silyl ester, tetracarboxylic acid ester and tetracarboxylic acid chloride. Further, as a preferable compound, (9H-fluorene-9,9-diyl) bis (2-methyl-4,1-phenylene) bis (1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate) Can be mentioned. The tetracarboxylic acid component may be used alone or in combination of two or more.

As the _{tetravalent group having an alicyclic structure of X 1} , a tetravalent group having an alicyclic structure having 4 to 40 carbon atoms is preferable, and at least one aliphatic 4- to 12-membered ring, more preferably an aliphatic group. It is more preferable to have a 4-membered ring or an aliphatic 6-membered ring. Tetravalent groups having a preferred aliphatic 4-membered ring or aliphatic 6-membered ring include:

(In the formula, R ₃₁ to R ₃₈ are independently directly bonded or divalent organic groups. R ₄₁ to R ₄₇ and R ₇₁ to R ₇₃ are independent formulas: -CH _2- , -CH = CH-, -CH ₂ CH _2- , -O-, -S- represents one selected from the group consisting of groups. R ₄₈ is an organic containing an aromatic ring or an alicyclic structure. Is the basis.)

Specific examples of R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ , and R ₃₈ include a direct bond, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an aliphatic hydrocarbon group having 1 to 6 carbon atoms. Examples thereof include an oxygen atom (—O—), a sulfur atom (—S—), a carbonyl bond, an ester bond, and an amide bond.

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

(In the formula, W ₁ is a directly bonded or divalent organic group, n ₁₁ to n ₁₃ each independently represent an integer of 0 to 4, and R ₅₁ , R ₅₂ , and R ₅₃ are independent of each other. It 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).

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

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

Examples of the tetracarboxylic acid component that gives the repeating unit of the formula (I) in which X _{1 is a tetravalent group having an alicyclic structure include 1,2,3,4-cyclobutanetetracarboxylic acid and isopropyridenediphenoxybis.} 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] octa-5-ene-2,3,7,8-tetracarboxylic acid Acid, tricyclo [4.2.2.02,5] decan-3,4,7,8-tetracarboxylic acid, tricyclo [4.2.2.02,5] deca-7-ene-3,4 9,10-Tetracarboxylic acid, 9-oxatricyclo [4.2.1.02,5] nonane-3,4,7,8-tetracarboxylic acid, norbornan-2-spiro-α-cyclopentanone- α'-Spiro-2''-norbornan 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, decahydro-1,4-ethano-5, 8-Metanonaphthalene-2 , 3,6,7-Tetracarboxylic acid, Tetradecahydro-1,4: 5,8: 9,10-Trimethanoanthracene-2,3,6,7-Tetracarboxylic acid and these tetracarboxylic acids Derivatives such as anhydrides, 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 two or more.

<Y ₁ and diamine component>
As the _{divalent group having an aromatic ring of Y 1} , a divalent group having an aromatic ring having 6 to 40 carbon atoms, more preferably 6 to 20 carbon atoms is preferable.

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

Here, since the high heat resistance, high transparency, and low coefficient of linear thermal expansion of the obtained polyimide can be compatible with each other, W ₁ can be directly bonded, or the formulas: -NHCO-, -CONH-, -COO-, -OCO-. It is particularly preferable that it is one selected from the group consisting of the groups represented by. Further, W ₁ is one selected from the group consisting of groups in which R ₆₁ to R ₆₈ are directly bonded or represented by the formulas: -NHCO-, -CONH-, -COO-, -OCO-. It is also particularly preferable that it is one of the divalent groups represented by the formula (6).

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

Examples thereof include compounds which are fluorenyl-containing groups represented by. Z ₁₁ and Z ₁₂ are independent, preferably identical, single-bonded or divalent organic groups, respectively. As Z ₁₁ and Z ₁₂ , organic groups containing an aromatic ring are preferable, and for example, the formula (3B1):

(Z ₁₃ and Z ₁₄ are single bonds independently of each other, -COO-, -OCO- or -O-, where if Z ₁₄ is attached to a fluorenyl group, then Z ₁₃ is -COO-, -OCO-. Alternatively, _{a structure in which Z 14} is a single bond in _{—O— is preferable; R 91} is an alkyl group or a phenyl group having 1 to 4 carbon atoms, preferably phenyl, and n is an integer of 0 to 4, preferably an integer of 0 to 4. It is 1.)
The structure represented by is preferable.

_{As another preferable group, a compound in which W 1} is a phenylene group in the above formula (4), that is, a terphenyldiamine compound can be mentioned, and a compound having all parabonds is particularly preferable.

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

As yet another preferable group, in the above formula (4), W ₁ is the following formula (3B2):

Examples thereof include compounds represented by.

Examples of the diamine component that gives the repeating unit of the general formula (I) in which 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-trizine, 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, Examples thereof include 2,4-bis (4-aminoanilino) -6-ethylamino-1,3,5-triazine and 2,4-bis (4-aminoanilino) -6-anilino-1,3,5-triazine. Examples of the diamine component that gives the repeating unit of the general formula (I) in which 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 can be mentioned. In addition, 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 Can be mentioned. The diamine component may be used alone or in combination of two or more.

As the _{divalent group having an alicyclic structure of Y 1} , a divalent group having an alicyclic structure having 4 to 40 carbon atoms is preferable, and at least one aliphatic 4- to 12-membered ring, more preferably an aliphatic group. It is more preferable to have a 6-membered ring.

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

(In the formula, V ₁ and V ₂ are independently directly bonded or divalent organic groups, and n ₂₁ to n ₂₆ each independently represent an integer of 0 to 4, and R ₈₁ to R _86. Are independently alkyl groups, halogen groups, hydroxyl groups, carboxyl groups, or trifluoromethyl groups having 1 to 6 carbon atoms, and R ₉₁ , R ₉₂ , and R ₉₃ are independently represented by the formulas: -CH _2- , respectively. -CH = CH-, -CH ₂ CH _2- , -O-, -S- is one selected from the group consisting of groups represented by.)

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

As the divalent group having an alicyclic structure, the following are particularly preferable because both the high heat resistance of the obtained polyimide and the low coefficient of linear thermal expansion can be achieved.

As the divalent group having an alicyclic structure, the following are preferable.

Examples of the diamine component that gives the repeating unit of the general formula (I) in which 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, diaminomethylbicycloheptan, diaminooxybicycloheptane, diaminomethyloxybicycloheptane, isophoronediamine, diaminotricyclo Decane, diaminomethyltricyclodecane, bis (aminocyclohexane) methane, bis (aminocyclohexyl) isopropylidene, 6,6'-bis (3-aminophenoxy) -3,3,3', 3'-tetramethyl -1,1'-spirobiindan, 6,6'-bis (4-aminophenoxy) -3,3,3', 3'-tetramethyl-1,1'-spirobiindan can be mentioned. The diamine component may be used alone or in combination of two or more.

As the tetracarboxylic acid component and the diamine component that give the repeating unit represented by the general formula (I), any aliphatic tetracarboxylic acid (particularly dianhydride) and / or aliphatic diamine other than the alicyclic type is 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 20 mol% or less, based on 100 mol% of the total of the tetracarboxylic acid component and the diamine component. It is preferably 10 mol% or less (including 0%).

In a preferred embodiment of the present invention _{, the repeating unit in which X 1} of the general formula (I) is a tetravalent group having an alicyclic structure is more than 60%, more preferably 70 mol% or more, more than all the repeating units. It is preferably contained in an amount of 80 mol% or more, more preferably 90 mol% or more, and particularly preferably 100 mol% or more. When the alicyclic structure is less than 100%, the rest is preferably a tetravalent group in which _{X 1 has an aromatic ring.} The tetravalent groups having a preferred alicyclic structure and the tetravalent groups having an aromatic ring are as described above. Further, 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, and Y ₁ The content of the repeating unit represented by the formula (I), which is a divalent group having an alicyclic structure, is preferably 50 mol% or less, more preferably 30 mol% or less or 30 with respect to all the repeating units. It is preferably less than mol%, more preferably 10 mol% or less.

In one preferred embodiment of the present invention, a polyimide precursor that provides a polyimide film having a relatively large elastic modulus is preferable. When a polyimide film is prepared using a polyimide precursor containing no siloxane compound (for example, 10 μm thickness), a polyimide of preferably 3.0 GPa or more, more preferably 3.5 GPa or more, and even more preferably 4.0 GPa or more. It is preferably applied to those that give a film.

In one preferred embodiment of the invention, a polyimide precursor that provides a polyimide having a relatively rigid structure is preferred. In particular, the polyimide precursor preferably contains a repeating unit having a Y ₁ having a rigid structure, as a specific example, the above-mentioned formula (4):

The structure represented by is preferred, where n ₁₁ to n ₁₃ and R ₅₁ , R ₅₂ , R ₅₃ are as defined above, but W ₁ is a direct bond, -CO-, -NHCO-,-. CONH-, -COO-, -OCO-, or the above equation (6):

In, a structure in which R ₆₁ to R ₆₈ are directly bonded, -CO-, -NHCO-, -CONH-, -COO- or -OCO- is preferable. Examples of diamine compounds giving this structure include p-phenylenediamine, 4,4'-diaminobenzanilide, 3,3'-bis (trifluoromethyl) benzidine, m-trizine and the like.

In this embodiment, Y ₁ having such a rigid structure is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, still more preferably 80 mol% or more, based on the total Y _1. It contains 90 mol% or more, and 100 mol% is also preferable. _{The polyimide precursor may have Y 1} having a non-rigid structure in order to adjust the physical properties, but is preferably 40 mol% or less, more preferably 30 mol% or less, and even more based on the total Y _1. It is preferably 20 mol% or less.

_{In this embodiment, X 1} derived from the tetracarboxylic acid component may be a tetravalent group having an aromatic ring or a tetravalent group having an alicyclic structure, but has high transparency. Since polyimide can be obtained, it is preferable that X ₁ is a tetravalent group having an aromatic ring containing fluorine, or a tetravalent group having an alicyclic structure. As the tetravalent group having an alicyclic structure, a group represented by the above formula (10) is preferable, and a group represented by the formula (11) is more preferable. For example, in order to adjust the physical properties, X ₁ may have another structure, but it is preferably 40 mol% or less, more preferably 30 mol% or less, and even more preferably 20 mol with respect _{to the total X 1.} % Or less.

The polyimide precursor can be produced from the above-mentioned tetracarboxylic acid component and diamine component. The polyimide precursor used in the present invention (a polyimide precursor containing at least one of the repeating units represented by the above formula (I)) depends on the chemical structure taken by _{R 1} and R _2.
1) Polyamic acid (R ₁ and R ₂ are hydrogen),
2) Polyamic acid ester ( _{at least a part of R 1} and R ₂ is an alkyl group),
3) 4) Polyamic acid silyl ester ( _{at least a part of R 1} and R ₂ is an alkylsilyl group),
Can be classified into. Then, the polyimide precursor can be easily produced by the following production methods for each of these categories. However, the method for producing the polyimide precursor used in the present invention is not limited to the following production method.

1) In the polyamic acid polyimide precursor, the tetracarboxylic acid dianhydride as the tetracarboxylic acid component and the diamine component are substantially equimolar, preferably the molar ratio of the diamine component to the tetracarboxylic acid component [molar of the diamine component]. Number / number of moles of tetracarboxylic acid component] is preferably 0.90 to 1.10, more preferably 0.95 to 1.05, and suppresses imidization at a relatively low temperature of, for example, 120 ° C. or lower. By reacting while reacting, it can be suitably obtained as a polyimide precursor solution.

More specifically, but not limited to, the diamine is dissolved in an organic solvent or water, and the tetracarboxylic dianhydride is gradually added to the solution with stirring, and the temperature is 0 to 120 ° C., preferably 5. A polyimide precursor can be obtained by stirring in the range of about 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 at the time of polymerization, and imidization proceeds due to heat, so that the polyimide precursor may not be stably produced. The order of adding diamine and tetracarboxylic dianhydride in the above production method is preferable because the molecular weight of the polyimide precursor tends to increase. It is also possible to reverse the order of addition of the diamine and the tetracarboxylic dianhydride in the above production method, which is preferable because the precipitates are reduced. When water is used as the solvent, imidazoles such as 1,2-dimethylimidazole or bases such as triethylamine are preferably 0.8 times equivalent to the carboxyl group of the polyamic acid (polyimide precursor) to be produced. It is preferable to add in the above amount.

2) Polyamic acid ester Tetracarboxylic acid dianhydride is reacted with an arbitrary alcohol to obtain a diester dicarboxylic acid, which is then reacted with a chlorination reagent (thionyl chloride, oxalyl chloride, etc.) to obtain a diester dicarboxylic acid chloride. A polyimide precursor can be obtained by stirring the diester dicarboxylic acid chloride and diamine at −20 to 120 ° C., preferably −5 to 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 at the time of polymerization, and imidization proceeds due to heat, so that the polyimide precursor may not be stably produced. A polyimide precursor can also be easily obtained by dehydrating and condensing a diesterdicarboxylic acid and a diamine 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 adding a solvent such as water or alcohol to reprecipitate.

3) Polyamic acid silyl ester (indirect method)
A diamine is reacted with a silylating agent 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 the tetracarboxylic dianhydride is gradually added while stirring to obtain 1 in the range of 0 to 120 ° C., preferably 5 to 80 ° C. A polyimide precursor can be obtained by stirring for about 72 hours. When the reaction is carried out at 80 ° C. or higher, the molecular weight fluctuates depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so that the polyimide precursor may not be stably produced.

4) Polyamic acid silyl ester (direct method)
A polyimide precursor is obtained by mixing the polyamic acid solution obtained by the method 1) with a silylating agent and stirring at 0 to 120 ° C., preferably 5 to 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 at the time of polymerization, and imidization proceeds due to heat, so that the polyimide precursor may not be stably produced.

Using a chlorine-free silylating agent as the silylating agent used in the methods 3) and 4) does not require purification of the silylated polyamic acid or the obtained polyimide. Suitable. Examples of the chlorine atom-free silylating agent include N, O-bis (trimethylsilyl) trifluoroacetamide, N, O-bis (trimethylsilyl) acetamide, and hexamethyldisilazane. N, O-bis (trimethylsilyl) acetamide and hexamethyldisilazane are particularly preferable because they do not contain fluorine atoms and are low in cost.

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

The solvent used in preparing the polyimide precursor is water or, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3. Aprotonic solvents such as -dimethyl-2-imidazolidinone and dimethyl sulfoxide are preferable, and any kind of solvent can be used without any problem as long as the raw material monomer component and the generated polyimide precursor are dissolved. The structure is not limited. As the solvent, 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, cyclic ester solvent such as α-methyl-γ-butyrolactone, carbonate solvent such as ethylene carbonate and propylene carbonate, glycol solvent such as triethylene glycol, m-cresol, p-cresol, 3 -Pharmonic solvents such as chlorophenol and 4-chlorophenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethylsulfoxide and the like are preferably adopted. In addition, other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methylcellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran. , Dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methylisobutylketone, diisobutylketone, cyclopentanone, cyclohexanone, methylethylketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, turpen, mineral spirit, petroleum A naphtha-based solvent or the like can also be used. A plurality of types of solvents can be used in combination.

The production of the polyimide precursor is not particularly limited, but the reaction is carried out by charging a monomer and a solvent at a concentration such that the solid content concentration (polyimide-equivalent mass concentration) of the polyimide precursor is, for example, 5 to 45% by mass.

The logarithmic viscosity of the polyimide precursor is not particularly limited, but the logarithmic viscosity of the N, N-dimethylacetamide solution at 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 preferable that it is 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 mechanical strength and heat resistance of the obtained polyimide are excellent.

As the imidization rate of the polyimide precursor, a wide range from 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), and imidization can proceed to adjust to a desired imidization rate. For example, a polyimide precursor with advanced imidization can be obtained by stirring the polyamic acid solution in the range of, for example, 80 to 230 ° C., preferably 120 to 200 ° C. for, for example, 1 to 24 hours. When the polyimide is solvent-soluble, the reaction mixture after the imidization reaction is put into a poor solvent to precipitate the polyimide, or a solution of a polyimide precursor (low imidization rate) (imidization if necessary). (Contains a catalyst and a dehydrating agent), for example, is cast on a carrier substrate, heat-treated, dried, and imidized (thermal imidized, chemically imidized), and the obtained polyimide is dissolved in a solvent. It may be used as a polyimide precursor for film production.

<Siloxane compound>
The siloxane compound used in the present invention is required to have a function of reducing the residual stress at the interface between the polyimide film / base material laminate. In addition to this, it is required not to impair the transparency of the polyimide film. Therefore, it is required that the polyimide precursor composition is a uniform solution without turbidity and that the polyimide film can be obtained as a uniform film without turbidity.

In one embodiment of the present invention, a phenyl group-containing linear siloxane compound is preferable, and one having a refractive index of 1.54 or more is particularly preferable. The phenyl group is preferably bonded to the terminal Si. The siloxane compound includes a silanol group (Si-OH), a group that hydrolyzes to a silanol group, for example, an alkoxysilyl group (Si-OR, R is an alkyl group), an aryloxysilyl group (Si-OAr, Ar is an aryl). Group), acyloxysilyl group (Si—OCOR, R is an alkyl group), ketooxime group (Si—N = CR ₂ , R is an alkyl group) and the like.

In one embodiment of the present invention, the siloxane compound is preferably a compound represented by the following general formula (S).

Here, n is an integer of 0 to 50, preferably 0 to 10, more preferably 0 to 5, and most preferably 0 to 2, and R ₁ to R ₈ are independent of each other and have a hydrogen atom and 1 to 1 to carbon atoms. It is selected from an alkyl group of 6 and an aryl group of 6 to 15 carbon atoms, and when n is 2 or more, R ₄ and R ₅ may each represent different groups in multiple appearances, provided that at least in the molecule. At least one of R ₁ to R ₈ represents a phenyl group such that it contains one phenyl group.

_Preferably, at least one of R 1 ~ _{R 3} and _R 6 ~ _{R 8,} preferably 2 or more phenyl groups, more preferably one or more of _R 1 ~ _{R 3} (preferably two or more) A phenyl group and one or more (preferably two or more) of _{R 6} to R _{8 are phenyl groups.} In this case, it is also preferable that at least one of _{R 4} and R _{5 is a phenyl group.} Further, in a preferred embodiment, the refractive index of the compound represented by the formula (S) is 1.54 or more.

When the above siloxane compound is used, a uniform polyimide precursor composition without turbidity can be obtained, a uniform polyimide film without turbidity can be obtained, and a sufficient effect of reducing residual stress can be obtained. Further, since the decrease in the 1% weight reduction temperature and the 5% weight reduction temperature of the obtained film even when the above siloxane compound is added is very small (see Examples), the polyimide film forms a barrier membrane, an element, etc. Therefore, even if it is reheated, the release of volatile substances / decomposition products is small. Therefore, when the polyimide precursor composition of the present invention is used, contamination of the manufacturing apparatus of the flexible electronic device is prevented, and problems such as swelling of the film / inorganic film do not occur, so that the yield is not adversely affected on the semiconductor element. Can manufacture flexible electronic devices well.

On the other hand, in the polyimide precursor composition to which the cyclic siloxane described in Patent Document 7 (Japanese Unexamined Patent Publication No. 2019-203117) is added, the cyclic siloxane, its hydrolyzate or its modified product and the like are contained in the film even after the film is formed. It remains and releases a lot of volatiles / decomposition products when the film is reheated. Therefore, when it is actually applied to device manufacturing, there is a concern that problems such as contamination of the manufacturing equipment and swelling of the film / inorganic film may occur.

<Formulation of polyimide precursor composition>
The polyimide precursor composition used in the present invention contains at least one polyimide precursor, at least one of the above siloxane compounds, and a solvent.

The content of the siloxane compound can be adjusted in consideration of the effect of reducing the residual stress between the polyimide film and the base material. In general, if it is too small, the effect of reducing residual stress is not sufficient, while if it is too large, not only is it wasted, but also the obtained polyimide film becomes turbid, and a uniform and transparent polyimide film may not be obtained. ..

The content of the siloxane compound is more than 0.5 parts by mass, preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass with respect to 100 parts by mass of the polyimide precursor in terms of polyimide. It is usually less than 30 parts by mass, preferably 28 parts by mass or less, more preferably 25 parts by weight or less, and even more preferably 23 parts by mass or less.

As the solvent, the above-mentioned solvent described as the solvent used when preparing the polyimide precursor can be used. Usually, the solvent used in preparing the polyimide precursor can be used as it is, that is, as the polyimide precursor solution, but it may be diluted or concentrated if necessary. The concentration of the polyimide precursor is not particularly limited, but is usually 5 to 45% by mass in terms of polyimide-equivalent mass concentration (solid content concentration). The siloxane compound is preferably present dissolved in the polyimide precursor composition. If the polyimide precursor composition is not completely dissolved and becomes turbid, a uniform and transparent polyimide film cannot usually be obtained. Therefore, the type and / or amount of the siloxane compound is determined from this viewpoint. Here, the polyimide reduced mass is the mass when all the repeating units are completely imidized.

The viscosity (rotational viscosity) of the polyimide precursor of the present invention is not particularly limited, but the rotational viscosity ^{measured using an E-type rotational viscometer at a temperature of 25 ° C. and a shear rate of 20 sec -1} is 0.01 to 1000 Pa · sec. Is preferable, and 0.1 to 100 Pa · sec is more preferable. Moreover, thixotropic property can be imparted as needed. When the viscosity is in the above range, it is easy to handle when coating or forming a film, repelling is suppressed, and the leveling property is excellent, so that a good film can be obtained.

The polyimide precursor composition of the present invention can be used as a chemical imidizing agent (acid anhydride such as acetic anhydride or an amine compound such as pyridine or isoquinolin), an antioxidant, an ultraviolet absorber, a filler (silica, etc.), if necessary. Inorganic particles, etc.), dyes, pigments, coupling agents such as silane coupling agents, primers, flame retardant materials, defoaming agents, leveling agents, polyimide control agents (fluid aids), and the like.

The polyimide precursor composition can be prepared by adding a siloxane compound or a solution of a siloxane compound to the polyimide precursor solution obtained by the method as described above and mixing them. If the reaction is not affected, the tetracarboxylic acid component and the diamine component may be reacted in the presence of the siloxane compound.

<Imidazole compound>
The polyimide precursor composition can also contain an imidazole compound. The inclusion of imidazole may improve, for example, at least one of transparency, thickness direction retardation, mechanical and thermal properties. The imidazole compound is not particularly limited, and examples thereof include 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, and benzimidazole. From the viewpoint of stability of the polyimide precursor composition and improvement of mechanical properties, it is particularly preferable to contain at least one imidazole compound selected from 2-phenylimidazole and benzimidazole.

The content of the imidazole compound in the polyimide precursor composition can be appropriately selected in consideration of the balance between the addition effect and the stability of the polyimide precursor composition. The amount of the imidazole compound is preferably more than 0.01 mol and less than 1 mol per 1 mol of repeating unit of the polyimide precursor. If the content of the imidazole compound is too low, mechanical properties such as elongation at break may be reduced, while if the content of the imidazole compound is too high, the storage stability of the polyimide precursor composition deteriorates. In some cases.

The content of the imidazole compound is more preferably 0.02 mol or more, still more preferably 0.025 mol or more, still more preferably 0.05 mol or more, and even more preferably, with respect to 1 mol of the repeating unit. It is 0.8 mol or less, still more preferably 0.6 mol or less, and even more preferably 0.4 mol or less.

<< Manufacture of polyimide film / base material laminate and flexible electronic device >>
In the polyimide film / base material laminate of the present invention, (a) a step of applying a polyimide precursor composition onto a base material, (b) the polyimide precursor is heat-treated on the base material, and the base material is used. It can be produced by a step of producing a laminate (polyimide film / base material laminate) in which a polyimide film is laminated on top. The method for producing a flexible electronic device of the present invention uses the polyimide film / base material laminate produced in the steps (a) and (b), and further steps, that is, (c) on the polyimide film of the laminate. In addition, there is a step of forming at least one layer selected from a conductor layer and a semiconductor layer, and (d) a step of peeling the base material and the polyimide film.

The polyimide precursor composition that can be used in the method of the present invention contains a polyimide precursor, a siloxane compound, and a solvent. As the siloxane compound, those described in the above-mentioned siloxane compound section can be used. As the polyimide precursor, those described in the section of the polyimide precursor composition can be used. The polyimide precursor described as preferable in the section of the polyimide precursor composition is also preferable in the method of the present invention, but is not particularly limited.

First, in step (a), a polyimide precursor composition is cast on a base material, imidized and desolvated by heat treatment to form a polyimide film, and a laminate (polyimide) of the base material and the polyimide film is formed. Film / substrate laminate) is obtained.

As the base material, a heat-resistant material is used, for example, a plate-like material such as a ceramic material (glass, alumina, etc.), a metal material (iron, stainless steel, copper, aluminum, etc.), a semiconductor material (silicon, compound semiconductor, etc.) or the like. A sheet-like base material, or a film such as a heat-resistant plastic material (polyimide, etc.) or a sheet-like base material is used. Generally, a flat and smooth plate shape is preferable, and generally, a glass substrate such as soda lime glass, borosilicate glass, non-alkali glass, or sapphire glass; a semiconductor (including compound semiconductor) substrate such as silicon, GaAs, InP, or GaN; Metal substrates such as iron, stainless steel, copper and aluminum are used.

A glass substrate is particularly preferable in the present invention. Glass substrates that are flat, smooth, and have a large area have been developed and are easily available. The problem of warpage becomes more apparent as the area of the substrate becomes larger, and the glass substrate is relatively prone to warpage in terms of rigidity. Therefore, the problem of using the glass substrate can be solved by applying the present invention. The thickness of the plate-shaped base material such as a glass substrate is not limited, but from the viewpoint of ease of handling, it is, for example, 20 μm to 4 mm, preferably 100 μm to 2 mm. The size of the plate-shaped base material is not particularly limited, but one side (long side in the case of a rectangle) is, for example, about 100 mm to 4000 mm, preferably about 200 mm to 3000 mm, and more preferably about 300 mm to 2500 mm. Is.

The base material such as these glass substrates may have an inorganic thin film (for example, a silicon oxide film) or a resin thin film formed on the surface.

The method of casting the polyimide precursor composition onto the substrate is not particularly limited, and for example, a slit coating method, a die coating method, a blade coating method, a spray coating method, an inkjet coating method, a nozzle coating method, a spin coating method, and screen printing. Examples thereof include conventionally known methods such as a method, a bar coater method, and an electrodeposition method.

In step (b), the polyimide precursor composition is heat-treated on the base material and converted into a polyimide film to obtain a polyimide film / base material laminate. The heat treatment conditions are not particularly limited, but are, 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. Treatment at ~ 500 ° C. is preferable. The heat treatment conditions when the polyimide solution is used 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. Hereinafter, it is more preferably 450 ° C. or lower.

The thickness of the polyimide film is preferably 1 μm or more, more preferably 2 μm or more, and further 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 cannot withstand stress and may be broken. The thickness of the polyimide film is preferably 100 μm or less, more preferably 50 μm or less, and further preferably 20 μm or less. If the thickness of the polyimide film is increased, it may be 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 the film thinner while maintaining sufficient resistance as a flexible device.

In one embodiment, the polyimide film has a 400 nm light transmittance of preferably 50% or more, more preferably 70% or more, still more preferably 75% or more, and most preferably 80% or more when measured with a film having a thickness of 10 μm. be.

In the present invention, the polyimide film / base material laminate is characterized in that the warp is small. The details of the measurement will be described later in the section << Evaluation of warpage, measurement of residual stress >>, but in one embodiment, the characteristics of the polyimide film are the same as those of the polyimide film in the polyimide film / silicon substrate (wafer) laminate. When evaluated by the residual stress between the silicon substrates, the residual stress is preferably 100 MPa or less, more preferably 95 MPa or less, preferably 73 MPa or less in different embodiments, preferably 60 MPa or less in different embodiments, and further different. In the embodiment, it is 40 MPa or less, and in a different embodiment, it is less than 27 MPa, more preferably less than 25 MPa. However, it is assumed that the polyimide film is placed at 23 ° C. in a dry state.

Using this as a base material, 6th generation Corning's Eagle-XG (registered trademark) (glass substrate, vertical size: 1500 mm, horizontal size: 1850 mm, diagonal size: 2382 mm, thickness: 0.5 mm, elastic modulus: Converted to 73.6 GPa), the warp size of the 10 μm thick polyimide film / glass substrate laminate is preferably 200 mm or less, more preferably 195 mm or less in diagonal size, and preferably 150 mm or less in different embodiments. In a further different embodiment, it is preferably 120 mm or less, in a further different embodiment it is 80 mm or less, and in a further different embodiment it is less than 64 mm, more preferably less than 58 mm. Here, the magnitude of the warp is the distance from the flat surface to the peripheral portion when the laminated body is placed on the flat surface as shown in FIG.

Further, in one embodiment of the present invention, the polyimide film has a breaking elongation of a film having a thickness of 10 μm, preferably 10% or more.

Further, in a different preferred embodiment of the present invention, the breaking strength of the polyimide film is preferably 150 MPa or more, more preferably 170 MPa or more, even more preferably 180 MPa or more, still more preferably 200 MPa or more. As the breaking strength, a value obtained from a film having a film thickness of, for example, about 5 to 100 μm can be used.

It is particularly preferable that the above preferable properties of the polyimide film and the laminate are satisfied at the same time.

The polyimide film in the polyimide film / base material laminate may have a second layer such as a resin film or an inorganic film on the surface. That is, after forming the polyimide film on the base material, the second layer may be laminated to form the flexible electronic device substrate. It preferably has at least an inorganic film, and particularly preferably one that functions as a barrier layer for water vapor, oxygen (air), or the like. Examples of the water vapor barrier layer 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. Examples thereof include an inorganic film containing an inorganic substance selected from the group consisting of metal oxides such as (ZrO _{2), metal nitrides and metal oxynitrides.} Generally, these thin film deposition methods 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). The method (chemical vapor deposition method) is known. The second layer may be a plurality of layers.

When the second layer is a plurality of layers, a resin film and an inorganic film can be composited. For example, a barrier layer / polyimide layer / barrier layer can be formed on the polyimide film in the polyimide film / base material laminate. An example of forming a three-layer structure can be mentioned.

In the step (c), the polyimide / base material laminate obtained in the step (b) is used on a polyimide film (including a polyimide film in which a second layer such as an inorganic film is laminated on the surface of the polyimide film). It forms at least one layer selected from a conductor layer and a semiconductor layer. These layers may be formed directly on a polyimide film (including a laminate of a second layer) or on a laminate of other layers required for the device, i.e. indirectly. good.

For the conductor layer and / or the semiconductor layer, an appropriate conductor layer and (inorganic, organic) semiconductor layer are selected according to the elements and circuits required by the target 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. The present invention may immediately shift to step (d) after step (c), or after forming at least one layer selected from a conductor layer and a semiconductor layer in step (c), further device structure is provided. After forming, the process may proceed to step (d).

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 having an inorganic film formed on the entire surface, if necessary. The 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 required for a liquid crystal display can also be formed by a known method. Further, a transparent electrode and a color filter may be formed on the polyimide film.

When manufacturing an organic EL display, for example, a TFT is formed on a polyimide film having an inorganic film formed on the entire surface, for example, in addition to a transparent electrode, a light emitting layer, a hole transport layer, an electron transport layer, and the like. can do.

Since the polyimide film preferable in the present invention is excellent in various properties such as heat resistance and toughness, the method for forming the circuit, element, and other structures required for the device is not particularly limited.

Next, in step (d), the base material and the polyimide film are peeled off. The peeling method may be a mechanical peeling method in which physical peeling is performed by applying an external force, or a so-called laser peeling method in which laser light is irradiated from the substrate surface to peel.

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

<< Evaluation of warpage, measurement of residual stress >>
FIG. 1 schematically shows the warp of the polyimide film / base material laminate in which the polyimide film 1 is formed on the base material 2. The warp of the polyimide film / base material laminate depends on the elastic modulus of the base material. Even if the same type of base material is used, the "warp value" differs depending on the thickness and size.

Further, according to the study of the present inventor, since the polyimide stretches due to moisture absorption, the degree of warpage of the polyimide film / base material laminate differs depending on the dry state of the polyimide film. In particular, when the evaluation is performed in the environmental atmosphere and the environmental temperature, the polyimide film tends to absorb moisture and the warp of the laminate tends to be small, whereas in the production of flexible electronic devices, it is under vacuum, reduced pressure, or inactive. Since the film formation is carried out in an atmosphere and the transportation and storage are also carried out in a dry atmosphere, the warp of the laminate becomes large. In other words, it is not possible to accurately evaluate the warpage that becomes a problem in the manufacture of electronic devices by measuring in the environmental atmosphere and environmental temperature. Therefore, it is preferable to measure the warp (or residual stress) in a dry state of the polyimide film. Therefore, it is conceivable to place the entire measuring device in a dry atmosphere, but this is not practical because the device becomes large and it takes time for the polyimide film to reach an equilibrium state.

One aspect of the present invention made to solve such a problem is
(1) A step of preparing a polyimide film / reference base material laminate in which a polyimide film is formed on a reference base material.
(2) A step of measuring the radius of curvature (warp) of the polyimide film / reference base material laminate at a plurality of measurement temperatures of 80 ° C. or higher.
(3) A step of calculating the residual stress at the measured temperature between the polyimide film in the polyimide film / reference base material laminate and the reference base material based on the measured radius of curvature (warp), and (4) a plurality. The present invention relates to a method for evaluating a residual stress of a polyimide film / base material laminate having a step of obtaining a residual stress at a predetermined temperature based on the residual stress at the measurement temperature of.

The reason for using the "reference base material" in the step (1) is that the warp of the polyimide film / base material laminate differs depending on the base material as described above. This is because it is preferable to use a reference base material (hereinafter referred to as a reference base material) suitable for the above. Since the main object of the present invention is to evaluate the warp of the polyimide film / glass substrate laminate, the following measurements and evaluations can be performed using the glass substrate. In, a silicon substrate (wafer) having a predetermined thickness was used as a reference base material. This is because the reflectance of the surface of the silicon substrate is high, and the warpage can be easily measured by an optical method. In particular, it is not limited to the silicon substrate, and can be selected in consideration of the measuring device and method.

The polyimide film / reference base material laminate is coated with (a) the polyimide precursor composition on the reference base material according to the above-mentioned method for producing the polyimide film / base material laminate, and (b) on the reference base material. The polyimide precursor can be heat-treated to be produced by laminating a polyimide film on a reference base material, and this can be used as a measurement sample.

Next, in step (2), the warp is measured at a relatively high temperature in which the polyimide film is in a dry state. The "relatively high temperature in a dry state" is, for example, 80 ° C. or higher, and 100 ° C. or higher is particularly preferable. The upper limit of the temperature is Tg of polyimide, and when Tg is not observed, the decomposition temperature is the upper limit. This is because the change in elastic modulus is small up to Tg, but the elastic modulus changes significantly when it exceeds Tg, so that it is not suitable as a measurement point to be extrapolated to, for example, room temperature in the next step (4). Usually, it is 250 ° C. or lower, preferably 200 ° C. or lower. Generally, the range of 100 ° C. to 200 ° C., for example, 100 ° C. to 150 ° C. is preferable.

Therefore, in the method of this embodiment, the warp may be measured at a plurality of different temperatures in such a temperature range, preferably at three or more different temperatures, and more preferably at four or more different temperatures. Further, although it depends on the measuring method and the measuring device, in order to improve the measurement accuracy, it is preferable to measure a plurality of times, for example, 3 times or more, for example, about 10 times or more at the same temperature to obtain an average value.

As the environment of the measuring method, the measuring device may be measured in a dry environment such as in dry air and an inert gas, but the environment in which the measuring device is placed is, for example, a normal environmental atmosphere and an environmental temperature (for example,). Even at 15 ° C. to 30 ° C. and relative humidity of 30 to 60%), the measurement sample and its surroundings become hot as described above, so that the measurement sample is placed in an extremely low humidity environment.

"Warp" can be measured by various methods and can be expressed by various indexes. A method of optically obtaining light (for example, laser light) from the reflection angle or the like is convenient and preferable. "Warp" can be expressed by the radius of curvature as an example.

Next, in the step (3), the residual stress S is calculated according to the mathematical formula 1 based on the measured value of the warp obtained in the step (2).

here,
E / (1-ν): Biaxial elastic modulus (Pa) of the substrate (reference base material: silicon wafer),
(100) For silicon, 1.805E11Pa,
h: Substrate thickness (m)
t: Polyimide film thickness (m)
R: Radius of curvature (m) of the measurement sample
_{1 / R = 1 / R 2} -1 / R 1
R ₁ : Radius of curvature of the substrate (silicon wafer) before film formation R ₂ : Radius of curvature after film formation S: Average value of residual stress (Pa)

Next, in step (4), the residual stress at a predetermined temperature is obtained based on the residual stress at a plurality of measurement temperatures calculated in step (3). The predetermined temperature is not a particularly fixed temperature, but a target temperature (temperature-of-interest) that can be selected according to the purpose, and may be a temperature at which the laminate is used and warpage is a problem. At room temperature, for example, 23 ° C. may be adopted.

In the example of FIG. 2, the residual stress obtained from five different measurement temperatures of 100 ° C. or higher is plotted on a graph with the temperature on the horizontal axis and the residual stress on the vertical axis. The predetermined temperature is 23 ° C. in this example. The method for obtaining the residual stress at a predetermined temperature from the measurement point is not particularly limited, but usually, as shown in FIG. 2, a linear approximation (by the least squares method) is performed and extrapolated to 23 ° C. to obtain the residual stress at 23 ° C. be able to.

In this way, the characteristics of the polyimide film can be evaluated by the residual stress at 23 ° C. between the polyimide film and the silicon substrate (as a reference base material).

Further, in order to estimate the warp of the polyimide film / target base material laminate using the target base material (for example, glass substrate) actually used for device manufacturing, the following is performed. First, the radius of curvature R of the warp generated in the polyimide film / target base material laminate is obtained by using the following mathematical formula 2.

here,
E: Tension elastic modulus (Pa) of the target base material
h: Thickness of target base material (m)
t: Polyimide film thickness (m)
S: Residual stress (Pa) at 23 ° C. (predetermined temperature) determined for the reference base material.
R: Radius of curvature (m)

The radius of curvature calculated from Equation 2 can be substituted into Equation 3 to calculate and estimate the magnitude of the warp (W) shown in FIG.

here,
L: Length (m) of the target base material, for example, diagonal distance, etc.
W: The size of the warp

According to the method for evaluating the residual stress of the polyimide film / base material laminate of the present embodiment as described above, the influence of moisture absorption of the polyimide film can be eliminated, and the following advantageous effects can be obtained. First, when the polyimide film in the laminated body is in a hygroscopic state, the warp is relatively small, which is often different from the warp generated in the actual process, but this embodiment enables an appropriate evaluation. In addition, stable evaluation has become possible without being affected by the measurement environment. Further, since the difference in warpage between the hygroscopic state and the dry state differs depending on the composition of the polyimide (because the hygroscopicity differs depending on the composition), the relative evaluation was meaningless in the hygroscopic state. You can now make accurate comparisons.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

In each of the following examples, the evaluation was performed by the following method.

<Evaluation of polyimide precursor composition (varnish)>
[Varnish uniformity]
The varnish containing the siloxane compound is visually observed, and if it is in a uniform state, it is evaluated as ◯, and if it is in a non-uniform state such as cloudiness or phase separation, it is evaluated as x.

<Evaluation of polyimide film>
[Polyimide film uniformity]
Visually observe the polyimide film, and if it is in a uniform state, mark it as ◯, and if it is cloudy, mark it as x.

[400 nm light transmittance]
Using an ultraviolet-visible spectrophotometer / V-650DS (manufactured by JASCO Corporation), the light transmittance of a polyimide film having a film thickness of about 10 μm at 400 nm was measured.

[Elastic modulus, elongation at break, strength at break]
A polyimide film with a thickness of about 10 μm was punched into a dumbbell shape of IEC450 standard to make a test piece, and using TENSILON manufactured by ORIENTEC, the chuck length was 30 mm, the tensile speed was 2 mm / min, and the initial elastic modulus and breaking point elongation were determined. The breaking strength was measured.

[Coefficient of linear thermal expansion (CTE)]
A polyimide film with a thickness of about 10 μm is cut into strips with a width of 4 mm to make test pieces, and using TMA / SS6100 (manufactured by SII Nanotechnology Co., Ltd.), the chuck length is 15 mm, the load is 2 g, and the temperature rise rate is 20 ° C. The temperature was raised to 500 ° C. in minutes. From the obtained TMA curve, the coefficient of linear thermal expansion from 150 ° C. to 250 ° C. was determined.

[1%, 5% weight loss temperature]
Using a polyimide film having a film thickness of about 10 μm as a test piece, the temperature was raised from 25 ° C. to 600 ° C. in a nitrogen stream at a heating rate of 10 ° C./min using a calorimeter measuring device (Q5000IR) manufactured by TA Instruments. From the obtained weight curve, the 1% and 5% weight loss temperatures were determined.

[Film thickness direction phase difference (R _th )]
A polyimide film having a film thickness of 10 μm was used as a test piece, and a phase difference measuring device (KOBRA-WR) manufactured by Oji Measuring Instruments Co., Ltd. was used to measure the phase difference of the film with an incident angle of 40 °. From the obtained phase difference, the phase difference in the thickness direction of the film having a film thickness of 10 μm was determined.

<Evaluation of polyimide film / base material laminate>
The warp of the polyimide film / silicon wafer laminate was measured using FLX-2320 manufactured by KLA Tencor. The radius of curvature of a single silicon wafer is measured in advance in an environment of 23 ° C. and 50% RH. Then, a polyimide film is formed on the silicon wafer. The radius of curvature of the laminate was measured and the residual stress was calculated. When the radius of curvature of the polyimide film / reference base material laminate was measured in a heated state, the radius of curvature of the silicon wafer alone was also measured at the same temperature.

<Raw materials>
The abbreviations, purity, etc. of the raw materials used in each of the following examples are as follows.

[Diamine component]
DABAN: 4,4'-diaminobenzanilide PPD: p-phenylenediamine BABP: 4,4'-bis (4-aminophenoxy) biphenyl TPE-Q: 1,4-bis (4-aminophenoxy) benzene TFMB: 2 , 2-bis (trifluoromethyl) benzidine BAFL: 9,9-bis (4-aminophenyl) fluorene 4,4'-ODA: 4,4'-diaminodiphenyl ether (or 4,4'-oxydianiline)
t-DACH: 1,4-diaminocyclohexane

[Tetracarboxylic acid component]
CpODA: Norbornan-2-spiro-α-cyclopentanone-α'-spiro-2 "-norbornan-5,5", 6,6 "-tetracarboxylic acid dianhydride DNDAxx: (4arH, 8acH) -decahydro- 1t, 4t: 5c, 8c-dimethanonaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acid dianhydride PMDA-H: Cyclohexanetetracarboxylic acid dianhydride PPHT: (Octahydro-1,3-dioxo-5- Isobenzofurancarboxylic acid) 1,4-phenylenediamide 6FDA: 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride s-BPDA: 3,3', 4,4'-biphenyltetracarboxylic acid Acid dianhydride PMDA: Piromellitic acid dianhydride

[solvent]
NMP: N-methyl-2-pyrrolidone

Table 1-1 shows the tetracarboxylic acid component and the diamine component used in Examples and Comparative Examples, and Tables 1-2 and 1-3 show the structures and refractive indexes of the siloxane compounds used in Examples and Comparative Examples.

<Example 1>
[Preparation of polyimide precursor composition]
In a reaction vessel replaced with nitrogen gas, 0.91 g (4 mmol) of DABAN, 0.54 g (5 mmol) of PPD and 0.37 g (1 mmol) of BABP were placed, and N-methyl-2-pyrrolidone was added to the total monomer. 29.73 g of an amount having a mass (total of diamine component and carboxylic acid component) of 16% by mass was added, and the mixture was stirred at 50 ° C. for 1 hour. 3.84 g (10 mmol) of CpODA was gradually added to this solution. Stirring at 70 ° C. for 4 hours gave a uniform and viscous polyimide precursor solution.

HFDSi as a siloxane compound was added to the polyimide precursor solution synthesized above in an amount of 10.0 parts by mass with respect to 100 parts by mass of the solid content of the polyimide precursor, mixed, and stirred at room temperature for 3 hours. A uniform and viscous polyimide precursor composition was obtained.

[Manufacturing of polyimide film / base material laminate]
In order to produce a polyimide film / base material laminate for evaluation of a polyimide film, a 6-inch Eagle-XG® (registered trademark) (500 μm thickness) manufactured by Corning Inc. was used as a glass substrate. The polyimide precursor composition is applied onto a glass substrate with a spin coater, and under a nitrogen atmosphere (oxygen concentration of 200 ppm or less), the polyimide film is thermally imidized by heating from room temperature to 415 ° C. on the glass substrate as it is. / A substrate laminate was obtained. The laminate was soaked in hot water to peel off the polyimide film from the glass substrate, dried, and then the characteristics of the polyimide film were evaluated. The film thickness of the polyimide film is about 10 μm.

[Manufacturing of polyimide film / reference base material laminate]
A 6-inch silicon wafer (625 μm thick, (100) substrate) was used as a reference base material for evaluating the polyimide film. The polyimide precursor composition is applied onto a silicon wafer with a spin coater, and under a nitrogen atmosphere (oxygen concentration of 200 ppm or less), it is heated from room temperature to 415 ° C. on the silicon wafer as it is to thermally imidize the polyimide film. / A reference base material laminate was obtained. The film thickness of the polyimide film in the laminate is about 10 μm.

The radius of curvature of the warp of the obtained polyimide film / reference base material laminate was measured at temperatures of 150 ° C., 140 ° C., 130 ° C., 120 ° C. and 110 ° C. The average value was calculated by measuring 20 times at each temperature. The residual stress at each temperature was calculated from the obtained radius of curvature, and the residual stress at 23 ° C. was obtained from the linear approximation by the least squares method. Further, the residual stress was obtained from the radius of curvature of the warp measured in an environment of 23 ° C. and 50% RH without heating. The results are shown in Table 2. 6th generation glass substrate (target base material) (Eagle-XG (registered trademark), vertical size: 1500 mm, horizontal size: 1850 mm, diagonal size: 2382 mm, thickness: 0.5 mm, elastic modulus: 73.6 GPa ) To produce a polyimide film / base material laminate, the value of warpage generated is calculated and shown in Table 2.

<Examples 2 to 15 (excluding Examples 6 and 9), Comparative Examples 1 to 21 (excluding Comparative Examples 11 and 14)>
In Example 1, the polyimide film was obtained in the same manner as in Example 1 except that the tetracarboxylic acid component, the diamine component, the siloxane compound, and the maximum temperature during film formation were changed to the compounds and conditions shown in Tables 2 to 5. / A reference base material laminate was produced, the warp of the laminate was measured in the same manner as in Example 1, and the residual stress at 23 ° C. was determined. The results are shown in Tables 2 to 5. Similarly, Tables 2 to show the estimated warpage values for the polyimide film / substrate laminate using the 6th generation glass substrate (Eagle-XG® 500 μm thickness, elastic modulus: 73.6 GPa). Shown according to 5.

<Example 6>
[Preparation of polyimide precursor composition]
2.25 g (9.9 mmol) of DABAN and 0.04 g (0.1 mmol) of BABP were placed in a reaction vessel replaced with nitrogen gas, and N-methyl-2-pyrrolidone was added to the total mass of the monomer (diamine component). 32.19 g was added in an amount such that the sum of the carboxylic acid components and the carboxylic acid component was 16% by mass, and the mixture was stirred at 50 ° C. for 1 hour. 3.84 g (10 mmol) of CpODA was gradually added to this solution. Stirring at 70 ° C. for 4 hours gave a uniform and viscous polyimide precursor solution.

2-Phenylimidazole as an imidazole compound was dissolved in 4 times the mass of N-methyl-2-pyrrolidone to obtain a uniform solution having a solid content concentration of 2-phenylimidazole of 20% by mass. The solution of the imidazole compound and the polyimide precursor solution synthesized above were mixed so that the amount of the imidazole compound was 0.1 mol per 1 mol of the repeating unit of the polyimide precursor, and the mixture was stirred at room temperature for 3 hours. A uniform and viscous polyimide precursor composition was obtained.

HIVAC-F-5 as a siloxane compound was added to the polyimide precursor solution synthesized above in an amount of 5.0 parts by mass with respect to 100 parts by mass of the solid content after the polyimide precursor was heated to form a polyimide. It was added, mixed and stirred at room temperature for 3 hours to give a uniform and viscous polyimide precursor composition. Using the obtained polyimide precursor composition, a polyimide film / reference base material laminate was produced in the same manner as in Example 1 except that the maximum temperature during film formation was changed to the conditions shown in Table 3, and evaluated. went.

<Comparative Example 11>
A polyimide film / reference base material laminate was produced and evaluated in the same manner as in Example 6 except that the siloxane compound was not added.

<Example 9>
[Preparation of partially imidized polyimide precursor composition]
DABAN 1.82 g (8 mmol) and TPE-Q 0.58 g (2 mmol) were placed in a reaction vessel replaced with nitrogen gas, and the total amount of the charged monomers (total of diamine component and carboxylic acid component) was 20% by mass. 14.50 g of N-methyl-2-pyrrolidone and 0.58 g of γ-butyrolactone were added, and the mixture was stirred at 50 ° C. for 1 hour. 3.02 g (10 mmol) of DNDAxx was gradually added to this solution. Stirring at 70 ° C. for 4 hours gave a uniform and viscous polyimide precursor solution. Then, the mixture was stirred at 120 ° C. for 6 hours to obtain a partially imidized polyimide precursor solution having an imidization ratio of 77%.

HIVAC-F-5 as a siloxane compound was added to the polyimide precursor solution synthesized above in an amount of 10.0 parts by mass with respect to 100 parts by mass of the solid content after the polyimide precursor was heated to form a polyimide. It was added, mixed and stirred at room temperature for 3 hours to give a uniform and viscous polyimide precursor composition. Using the obtained polyimide precursor composition, a polyimide film / reference base material laminate was produced in the same manner as in Example 1 except that the maximum temperature during film formation was changed to the conditions shown in Table 4, and evaluated. went.

<Comparative Example 14>
A polyimide film / reference base material laminate was produced and evaluated in the same manner as in Example 9 except that the siloxane compound was not added.

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

Claims

Polyimide precursors (provided that the polyimide precursors are not imidized or are partially or completely imidized),
Contains a phenyl group-containing linear siloxane compound having a refractive index of 1.54 or more in an amount of more than 0.5 parts by mass to less than 30 parts by mass with respect to 100 parts by mass of the polyimide precursor in terms of polyimide, and a solvent. A polyimide precursor composition comprising.
The composition according to claim 1, wherein the siloxane compound does not have a silanol group and a group that hydrolyzes to become a silanol group.
The composition according to claim 1 or 2, wherein the phenyl group is bonded to the terminal Si.
Polyimide precursors (provided that the polyimide precursors are not imidized or are partially or completely imidized),
Contains a phenyl group-containing linear siloxane compound represented by the following formula (S) and a solvent in an amount of more than 0.5 parts by mass to less than 30 parts by mass with respect to 100 parts by mass of the polyimide precursor in terms of polyimide. A polyimide precursor composition comprising.

(In the formula, n is an integer of 0 to 10, and R 1 to R 8 are independently selected from a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 15 carbon atoms, and n When is 2 or more, R 4 and R 5 may each represent different groups in a plurality of appearances, and at least one of R 1 to R 8 represents a phenyl group.)
The composition according to claim 4, wherein one or more of R 1 to R 3 is a phenyl group and one or more of R 6 to R 8 is a phenyl group.
A claim, wherein the polyimide precursor contains 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 to 5.

(In the general formula I, X 1 is a tetravalent aliphatic group or an aromatic group, Y 1 is a divalent aliphatic group or an aromatic group, and R 1 and R 2 are independent of each other and hydrogen. Atomic, an alkyl group having 1 to 6 carbon atoms or an alkylsilyl group having 3 to 9 carbon atoms.)
The content of the repeating unit represented by the general formula (I), in which X 1 is a tetravalent group having an alicyclic structure and Y 1 is a divalent group having an alicyclic structure, is based on all the repeating units. The composition according to claim 6, wherein the composition is 50 mol% or less.
The composition according to claim 6, wherein X 1 in the general formula (I) is a tetravalent group having an aromatic ring, and Y 1 is a divalent group having an aromatic ring.
The composition according to claim 6, wherein X 1 in the general formula (I) is a tetravalent group having an alicyclic structure, and Y 1 is a divalent group having an aromatic ring.
The composition according to claim 6, wherein X 1 in the general formula (I) is a tetravalent group having an aromatic ring, and Y 1 is a divalent group having an alicyclic structure.
The X 1 of the general formula (I) contains 60 percent proportion of the total repeating units of repeating units is a tetravalent group having an alicyclic structure (however, tetravalent X 1 has an alicyclic structure The content of the repeating unit represented by the general formula (I), which is a group of the above and Y 1 is a divalent group having an alicyclic structure, is 50 mol% or less with respect to all the repeating units). The composition according to claim 6.
Y 1 of the general formula (I) is the following formula (4):

{In formula (4), n 11 to n 13 independently represent integers of 0 to 4, and R 51 , R 52 , and R 53 independently represent alkyl groups and halogen groups having 1 to 6 carbon atoms, respectively. It is a hydroxyl group, a carboxyl group, or a trifluoromethyl group, and W 1 is a direct bond, -CO-, -NHCO-, -CONH-, -COO-, -OCO-, or the formula (6) :.

(R 61 to R 68 are direct bonds, -CO-, -NHCO-, -CONH-, -COO- or -OCO-.)}
Group A composition according to claim 6, characterized in that it comprises an amount of more than 60 mol% relative to the total Y 1 represented in.
A polyimide film obtained from the polyimide precursor composition according to any one of claims 1 to 12.
A polyimide film obtained from the polyimide precursor composition according to any one of claims 1 to 12, and a polyimide film.
A polyimide film / base material laminate characterized by having a base material.
The laminate according to claim 14, wherein the base material is a glass substrate.
(A) The step of applying the polyimide precursor composition according to any one of claims 1 to 12 onto a base material, and (b) the polyimide precursor being heat-treated on the base material to obtain the above. A method for producing a polyimide film / substrate laminate, which comprises a step of laminating a polyimide film on a substrate.
The manufacturing method according to claim 16, wherein the base material is a glass substrate.
(A) A step of applying the polyimide precursor composition according to any one of claims 1 to 12 onto a substrate.
(B) A step of heat-treating the polyimide precursor on the base material to produce a polyimide film / base material laminate in which the polyimide film is laminated on the base material.
Flexible electrons having (c) a step of forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminated body, and (d) a step of peeling the base material and the polyimide film. How to make the device.
The production method according to claim 18, wherein the base material is a glass plate.