KR20220158783A - Polyimide precursor composition and polyimide film/substrate laminate - Google Patents

Abstract

A polyimide precursor composition capable of producing a polyimide film/substrate laminate having small warpage and having excellent stability is provided. The polyimide precursor composition comprises a polyimide precursor, a phenyl group-containing linear siloxane compound having a positive refractive index of 1.54 or more and a solvent in an amount of more than 0.5 parts by mass and less than 30 parts by mass based on 100 parts by mass in terms of polyimide of the polyimide precursor. contain

Description

Polyimide precursor composition and polyimide film/substrate laminate

The present invention relates to a polyimide precursor composition and a polyimide film/substrate laminate having reduced warpage, which are suitably used for electronic device applications such as substrates for flexible devices, for example. Further, it relates to a method for manufacturing a flexible electronic device using the composition.

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

In displays such as liquid crystal displays and organic EL displays, semiconductor elements such as TFTs for driving each pixel are formed. For this reason, heat resistance and dimensional stability are requested|required of a board|substrate. Polyimide films are promising as substrates for display applications in that they are excellent in heat resistance, chemical resistance, mechanical strength, electrical properties, dimensional stability, and the like.

Since polyimide is generally colored yellowish brown, its use in transmissive devices such as liquid crystal displays with a backlight has been limited. However, in recent years, polyimide films with excellent transparency in addition to mechanical and thermal properties have been developed. Therefore, expectations are further rising as substrates for display applications (see Patent Literatures 1 to 3).

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

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

International Publication No. 2012/011590 International Publication No. 2013/179727 International Publication No. 2014/038715 Japanese Unexamined Patent Publication No. 2010-202729 International Publication No. 2018/221607 International Publication No. 2014/098235 Japanese Unexamined Patent Publication No. 2019-203117

When the methods of Patent Literatures 4 and 5 are applied to actual production, warpage occurs in the polyimide film/glass substrate laminate, making it difficult to form elements with high precision, or handling properties deteriorating in some cases. . In particular, in the case of using a large glass substrate, as a specific example, for example, manufacturing a large flexible electronic device (eg, large display device) or a plurality of flexible electronic devices (eg, display device) from one substrate In the case of application to the so-called multifaceted method, there are cases where the warpage extends to a level that cannot be ignored.

Patent Document 6 is an inorganic film by a polyimide precursor in which a silicone structure (polysiloxane structure) is introduced into a skeleton by using silicon diamine together with 2,2-bis (trifluoromethyl) benzidine as a diamine component. However, it is disclosed that residual stress between the support substrate and the polyimide film can be reduced. However, since the structure of polyimide is limited, versatility is insufficient, and target physical properties may not be obtained. In addition, a problem that the reactive group portion is easy to degas and the amount of degassing during heating is increased is also pointed out (Patent Document 7, 0008).

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

However, the specific cyclic siloxane compound and the specific linear siloxane compound described in Patent Literature 7 have a small effect on stress relaxation, for example, when added in a small amount, there is almost no effect on stress relaxation, and when added in a large amount, poly Since it remains in the mid film and is released upon reheating, there is a problem that devices are contaminated when forming barrier films, elements, and the like.

The present invention has been made in view of the conventional problems, and a main object is to provide a polyimide precursor composition capable of producing a polyimide film/substrate laminate having small warpage and having excellent stability. Another 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/substrate laminate, and an object of another aspect of the present invention is to provide a polyimide film obtained by using the polyimide precursor composition It is to provide a manufacturing method of a flexible electronic device using a precursor composition, and a flexible electronic device.

If this application incorporates the main disclosure, it is as follows.

1. Polyimide precursor (provided that the polyimide precursor is not imidized or is partially or completely imidized);

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 and less than 30 parts by mass based on 100 parts by mass in terms of polyimide of the polyimide precursor, and

menstruum

Polyimide precursor composition characterized in that it contains.

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

3. The composition according to the above item 1 or 2, characterized in that a phenyl group is bonded to the terminal Si.

4. Polyimide precursor (provided that the polyimide precursor is not imidized or is partially or completely imidized);

A phenyl group-containing linear siloxane compound represented by the following formula (S) in an amount of more than 0.5 parts by mass and less than 30 parts by mass based on 100 parts by mass in terms of polyimide of the polyimide precursor, and

menstruum

Polyimide precursor composition characterized in that it contains.

(Wherein, n is an integer of 0 to 50, preferably 0 to 10, R ₁ to R ₈ are each 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, when n is 2 or more, each of R ₄ and R ₅ may represent a different group in a plurality of occurrences, and at least one of R ₁ to R ₈ represents a phenyl group.)

In particular, it is preferable that the phenyl group-containing linear siloxane compound having a refractive index of 1.54 or higher according to the above item 1 is at least one selected from the phenyl group-containing linear siloxane compound represented by the formula (S).

5. The composition according to item 4 above, wherein at least one of R ₁ to R ₃ is a phenyl group and at least one of R ₆ to R ₈ is a phenyl group.

6. The above item 1, wherein the polyimide precursor contains a repeating unit selected from structures in which at least one of the structure represented by the following general formula (I) and the amide structure in the general formula (I) is imidized. The composition according to any one of 5 to 5.

(In Formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, R ₁ and R ₂ are independently of each other a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or It is an alkylsilyl group having 3 to 9 carbon atoms.)

7. X ₁ is a tetravalent group having an alicyclic structure, and Y ₁ is a divalent group having an alicyclic structure, characterized in that the content of the repeating unit represented by the general formula (I) is 50 mol% or less with respect to all repeating units The composition according to the above item 6.

8. The composition according to item 6 above, 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. The composition according to item 6 above, 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. The composition according to item 6 above, 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. Containing a repeating unit in which X ₁ of the general formula (I) is a tetravalent group having an alicyclic structure in a proportion of more than 60% of all repeating units (provided that X ₁ is a tetravalent group having an alicyclic structure and Y The content of the repeating unit represented by general formula (I), wherein ₁ is a divalent group having an alicyclic structure, is 50 mol% or less with respect to all repeating units).

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

{In Formula (4), n ₁₁ to n ₁₃ each independently represents an integer of 0 to 4, and R ₅₁ , R ₅₂ , and R ₅₃ are each independently an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, A carboxyl group or a trifluoromethyl group, W ₁ is a direct bond, -CO-, -NHCO-, -CONH-, -COO-, -OCO-, or Formula (6):

(R ₆₁ to R ₆₈ are a direct bond, -CO-, -NHCO-, -CONH-, -COO- or -OCO-.)}

The composition according to the above item 6, comprising groups represented by in an amount of 60 mol% or more with respect to the total Y ₁ .

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

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

write

A polyimide film/substrate laminate characterized by having a.

15. The laminate according to item 14, wherein the substrate is a glass substrate.

16. (a) Step of applying the polyimide precursor composition according to any one of the above items 1 to 12 onto a substrate, and

(b) a step of heating the polyimide precursor on the substrate and laminating a polyimide film on the substrate

Method for producing a polyimide film/substrate laminate having a.

17. The manufacturing method according to the above item 16, wherein the substrate 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 heating the polyimide precursor on the substrate to produce a polyimide film/substrate laminate in which a polyimide film is laminated on the substrate;

(c) a step of forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate, and

(d) step of peeling the substrate and the polyimide film

Method for manufacturing a flexible electronic device having a.

19. The manufacturing method according to the above item 18, wherein the substrate is a glass plate.

ADVANTAGE OF THE INVENTION According to this invention, it is possible to manufacture a polyimide film/substrate laminate with small warpage, and it is possible to provide a polyimide precursor composition with excellent stability. According to the embodiment of the polyimide precursor composition of the present invention, (i) in addition to the effect that it is possible to manufacture a polyimide film / glass substrate laminate with small warpage, (ii) the obtained polyimide film has excellent transparency (iii) exhibits one or more of the following effects: that the obtained polyimide film has excellent mechanical properties such as elongation at break, and (iv) stability (e.g., evaluated by uniformity, change in viscosity, etc.); In a preferred embodiment, in addition to the effect of (i), all of the effects of (ii) to (iv) are exhibited.

Furthermore, according to one aspect of the present invention, a polyimide film obtained by using the polyimide precursor composition and a polyimide film/substrate laminate can be provided. Further, according to another aspect of the present invention, a method for manufacturing a flexible electronic device using the polyimide precursor composition and a flexible electronic device can be provided.

1 is a diagram schematically showing warpage of a polyimide film/substrate laminate.
2 is a view for explaining a method of obtaining residual stress of a polyimide film/reference substrate laminate.

In this application, "flexible (electronic) device" means that the device itself is flexible, and usually, a semiconductor layer (a transistor, diode, etc. as an element) is formed on a substrate to complete the device. A "flexible (electronic) device" is distinguished from, for example, a COF (Chip On Film) device 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, there is no problem at all in using "hard" semiconductor elements such as IC chips mounted on a flexible substrate, electrically connected, or fused together. . Examples of flexible (electronic) devices that are suitably used include display devices such as liquid crystal displays, organic EL displays, and electronic paper, solar cells, and light-receiving devices such as CMOS.

Below, the polyimide precursor composition of this invention is demonstrated, and then the manufacturing method of a flexible electronic device is demonstrated.

<<Polyimide Precursor Composition>>

A polyimide precursor composition for forming a polyimide film contains a polyimide precursor, a specific siloxane compound and a solvent. Both the polyimide precursor and the specific siloxane compound are dissolved in a solvent.

In this application, the term "polyimide precursor" is used in the sense of a precursor capable of forming polyimide in a polyimide film. That is, the term "polyimide precursor" includes polyamic acids and derivatives (precisely defined by formula (I)), partially imidized polyamic acids and derivatives partially imidized, polyimide, and mixtures thereof. do. That is, the polyimide precursor is not imidated, or partially or completely imidated. Therefore, in this application, the term "polyimide precursor" includes all ranges of imidization rate 0% to 100%. However, in the polyimide precursor composition, all are dissolved in the solvent.

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

(In Formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, R ₁ and R ₂ are independently of each other a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or It is an alkylsilyl group having 3 to 9 carbon atoms.)

It has a repeating unit denoted by . Particularly preferred is a polyamic acid in which R ₁ and R ₂ are hydrogen atoms.

Further, another example of the polyimide precursor is a polyimide precursor in which imidation has progressed partially or completely, and at least one of the two amide structures (-CONH-) in the general formula (I) is -COOR ₁ and/or - A repeating unit imidized by reacting with COOR ₂ is included.

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

(In the formula, X ₁ is a tetravalent aliphatic or aromatic group, and Y ₁ is a divalent aliphatic or aromatic group.)

It has a repeating unit denoted by . In the case of a soluble polyimide, it can be contained in the polyimide precursor composition as a "polyimide precursor".

Below, the chemical structure of this polyimide is described as the structure of X ₁ and Y ₂ in the repeating units (general formulas (I) and (II)) and the monomers used for production (tetracarboxylic acid component, diamine component, other component), and then the manufacturing method will be described.

In the present specification, the tetracarboxylic acid component is tetracarboxylic acid, tetracarboxylic dianhydride, other tetracarboxylic acid silyl esters, tetracarboxylic acid esters, and tetracarboxylic acid esters used as raw materials for producing polyimide. and tetracarboxylic acid derivatives such as acid chloride. Although not particularly limited, it is convenient to use tetracarboxylic dianhydride for production, and an example using tetracarboxylic dianhydride as the tetracarboxylic acid component will be described in the following description. In addition, the diamine component is a diamine compound having two amino groups (-NH ₂ ) used as a raw material for producing polyimide.

In addition, in this specification, a polyimide film means both what is formed on a (carrier) base material and exists in a laminated body, and the film after peeling a base material. In addition, the material constituting the polyimide film, that is, the material obtained by heating (imidizing) the polyimide precursor composition may be referred to as a "polyimide material".

The polyimide contained in the polyimide film is not particularly limited, and the tetracarboxylic acid component and the diamine component are composed of a polyimide appropriately selected from aromatic compounds and aliphatic compounds. The aliphatic compound of the diamine component is preferably an alicyclic compound. As a polyimide, a wholly aromatic polyimide, a semi-cyclic polyimide, and a fully cyclic polyimide are mentioned, for example.

Although not particularly limited, since the obtained polyimide material has excellent heat resistance, it is preferable that X ₁ in general formula (I) is a tetravalent group having an aromatic ring and Y ₁ is a divalent group having an aromatic ring. Further, since the obtained polyimide material has excellent heat resistance and excellent transparency, it is preferable that X ₁ is a tetravalent group having an alicyclic structure and Y ₁ is a divalent group having an aromatic ring. Further, since the obtained polyimide material has excellent heat resistance and excellent dimensional stability, it is preferable that X ₁ is a tetravalent group having an aromatic ring and Y ₁ is a divalent group having an alicyclic structure.

In terms of properties of the polyimide material obtained, for example, transparency, mechanical properties, heat resistance, etc., X ₁ is a tetravalent group having an alicyclic structure, Y ₁ is a divalent group having an alicyclic structure, represented by formula (I) The content of the displayed repeating unit is preferably 50 mol% or less, more preferably 30 mol% or less or less than 30 mol%, more preferably 10 mol% or less, based on all repeating units.

In some embodiments, X ₁ is a tetravalent group having an aromatic ring, and Y ₁ is a divalent group having an aromatic ring, and the content of one or more types of repeating units of the formula (I) is, in total, in all repeating units. It is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 100 mol%. In this embodiment, especially when a highly transparent polyimide material is required, it is preferable that the polyimide contains a fluorine atom. That is, polyimide is a repeating unit of the above general formula (I) in which X ₁ is a tetravalent group having an aromatic ring containing a fluorine atom and/or Y ₁ is a divalent group having an aromatic ring containing a fluorine atom. It is preferable to include one or more types of repeating units of formula (I).

In a certain embodiment, in the polyimide precursor, X ₁ is a tetravalent group having an alicyclic structure, and Y ₁ is a divalent group having an aromatic ring. , preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 100 mol% based on all repeating units it is desirable

In a certain embodiment, in the polyimide precursor, X ₁ is a tetravalent group having an aromatic ring, and Y ₁ is a divalent group having an alicyclic structure, and the content of one or more types of repeating units of the formula (I) is a total of , It is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 100 mol% based on all repeating units. desirable.

Among them, the polyimide precursor contained in the polyimide precursor composition of the present invention is a repeating unit of the above general formula (I) in which X ₁ is a tetravalent group having an alicyclic structure and Y ₁ is a divalent group having an aromatic ring ( a), and at least one selected from the group consisting of the repeating unit (b) of the formula (I), wherein X ₁ is a tetravalent group having an aromatic ring and Y ₁ is a divalent group having an alicyclic structure. Preferably, it is particularly preferable to contain the repeating unit (a) of the above 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. 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% or more, based on all repeating units, as described above. mol% or more, more preferably 90 mol% or more, 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 of 6 to 40 carbon atoms is preferable.

As a tetravalent group which has an aromatic ring, the following are mentioned, for example.

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

which of However, Z ₂ in the formula is a divalent organic group, Z ₃ and Z ₄ are each independently an amide bond, an ester bond, and a carbonyl bond, and Z ₅ is an organic group containing an aromatic ring.)

Specifically as Z ₂ , an aliphatic hydrocarbon group having 2 to 24 carbon atoms and an aromatic hydrocarbon group having 6 to 24 carbon atoms are exemplified.

Specifically as Z ₅ , an aromatic hydrocarbon group having 6 to 24 carbon atoms is exemplified.

As the tetravalent group having an aromatic ring, since high heat resistance and high transparency of the polyimide film obtained are compatible, the following ones are particularly preferred.

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

Here, since high heat resistance, high transparency, and a low linear thermal expansion coefficient of the obtained polyimide film can be compatible, it is more preferable that Z ₁ is a direct bond.

As a further preferred group, in the above formula (9), Z ₁ is represented by the following formula (3A):

A compound which is a fluorenyl-containing group represented by is exemplified. Z ₁₁ and Z ₁₂ are each independently, preferably the same, and are a single bond or a divalent organic group. As Z ₁₁ and Z ₁₂ , an organic group containing an aromatic ring is preferable, for example, formula (3A1):

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

The structure represented by is preferred.

As the tetracarboxylic acid component giving the repeating unit of the general formula (I) in which X ₁ is a tetravalent group having an aromatic ring, for example, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane , 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid, pyromellitic acid, 3,3 ',4 ,4'-benzophenonetetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 4,4'- Oxydiphthalic acid, bis(3,4-dicarboxyphenyl)sulfone, m-terphenyl-3,4,3',4'-tetracarboxylic acid, p-terphenyl-3,4,3',4' -Tetracarboxylic acid, biscarboxyphenyldimethylsilane, bisdicarboxyphenoxydiphenyl sulfide, sulfonyldiphthalic acid, tetracarboxylic dianhydride, tetracarboxylic acid silyl ester, tetracarboxylic acid ester, tetracarboxylic acid Derivatives, such as boxylic acid chloride, are mentioned. As the tetracarboxylic acid component giving the repeating unit of the general formula (I) in which X ₁ is a tetravalent group having an aromatic ring containing a fluorine atom, for example, 2,2-bis(3,4-dicarboxyphenyl) ) Hexafluoropropane, tetracarboxylic acid dianhydride thereof, tetracarboxylic acid silyl ester, tetracarboxylic acid ester, tetracarboxylic acid chloride, and other derivatives thereof. Further, as a preferred compound, (9H-fluorene-9,9-diyl)bis(2-methyl-4,1-phenylene)bis(1,3-dioxo-1,3-dihydroisobenzofuran- 5-carboxylate). A tetracarboxylic acid component may be used independently, and may also be used in combination of multiple types.

As the tetravalent group having an alicyclic structure of X ₁ , a tetravalent group having an alicyclic structure of 4 to 40 carbon atoms is preferable, and a tetravalent group having at least one aliphatic 4- to 12-membered ring, more preferably an aliphatic 4-membered ring or an aliphatic 6-membered ring. it is more preferable Examples of the tetravalent group having a 4-membered aliphatic ring or a 6-membered aliphatic ring include the following ones.

(In the formula, R ₃₁ to R ₃₈ are each independently a direct bond or a divalent organic group. R ₄₁ to R ₄₇ and R ₇₁ to R ₇₃ are each independently in the formula: -CH ₂ -, - CH=CH-, -CH ₂ CH ₂ -, -O-, represents one member selected from the group consisting of -S- R ₄₈ is an organic group containing an aromatic ring or an alicyclic structure.)

Specifically, as R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ , R ₃₈ , a direct bond or an aliphatic hydrocarbon group having 1 to 6 carbon atoms or 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.

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

Specifically as W ₁ , a direct bond, a divalent group represented by the following formula (5), and a divalent group represented by the following formula (6) are exemplified.

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

As the tetravalent group having an alicyclic structure, since high heat resistance, high transparency, and low linear thermal expansion coefficient of the obtained polyimide can be compatible, the following ones are particularly preferred.

As a tetracarboxylic acid component giving the repeating unit of Formula (I) where X ₁ is a tetravalent group having an alicyclic structure, for example, 1,2,3,4-cyclobutanetetracarboxylic acid, isopropylidenediphene Koxybisphthalic 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) carboxylic acid), 4,4'-oxybis (cyclohexane-1,2-dicarboxylic acid), 4,4'-thiobis (cyclohexane-1,2-dicarboxylic acid), 4,4 '-sulfonylbis(cyclohexane-1,2-dicarboxylic acid), 4,4'-(dimethylsilanediyl)bis(cyclohexane-1,2-dicarboxylic acid), 4,4'- (tetrafluoropropane-2,2-diyl)bis(cyclohexane-1,2-dicarboxylic acid), octahydropentalene-1,3,4,6-tetracarboxylic acid, bicyclo[2.2. 1]heptane-2,3,5,6-tetracarboxylic acid, 6-(carboxymethyl)bicyclo[2.2.1]heptane-2,3,5-tricarboxylic acid, bicyclo[2.2.2] Octane-2,3,5,6-tetracarboxylic acid, bicyclo[2.2.2]oct-5-ene-2,3,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5] Decane-3,4,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5]dec-7-ene-3,4,9,10-tetracarboxylic acid, 9-oxatricyclo[4.2 .1.02,5] nonane-3,4,7,8-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane 5,5'',6,6''-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2c,3c,6c,7c-tetracarboxylic acid, (4arH ,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2t,3t,6c,7c-tetracarboxylic acid, decahydro-1,4-ethano-5,8-methanonaphthalene -2,3,6,7-tetracarboxylic acid, tetradecahydro -1,4:5,8:9,10-trimethanoanthracene-2,3,6,7-tetracarboxylic acid, tetracarboxylic dianhydride thereof, tetracarboxylic acid silyl ester, tetracarboxylic acid and derivatives such as boxylic acid esters and tetracarboxylic acid chlorides. A tetracarboxylic acid component may be used independently, and may also be used in combination of multiple types.

<Y ₁ and diamine component>

As the divalent group having an aromatic ring for Y ₁ , a divalent group having an aromatic ring having 6 to 40 carbon atoms, more preferably 6 to 20 carbon atoms is preferable.

As a divalent group which has an aromatic ring, the following are mentioned, for example.

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

Specifically as W ₁ , a direct bond, a divalent group represented by the following formula (5), and a divalent group represented by the following formula (6) are exemplified.

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

Here, since high heat resistance, high transparency, and a low linear thermal expansion coefficient of the obtained polyimide can be compatible, W ₁ is a direct bond or a group represented by formulas: -NHCO-, -CONH-, -COO-, or -OCO- It is especially preferable that it is 1 type selected from the group which consists of. Further, in the formula (6), wherein W ₁ and R ₆₁ to R ₆₈ are selected from the group consisting of a direct bond or a group represented by formulas: -NHCO-, -CONH-, -COO-, and -OCO-; Any of the divalent groups shown is particularly preferred.

As a further preferred group, in the above formula (4), W ₁ is represented by the following formula (3B):

A compound which is a fluorenyl-containing group represented by is exemplified. Z ₁₁ and Z ₁₂ are each independently, preferably the same, and are a single bond or a divalent organic group. As Z ₁₁ and Z ₁₂ , an organic group containing an aromatic ring is preferable, for example, formula (3B1):

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

The structure represented by is preferred.

As another preferred group, in the formula (4), a compound wherein W ₁ is a phenylene group, ie, a terphenyldiamine compound, is particularly preferred.

As another preferred group, in the formula (4), W ₁ is a structure of one first phenyl ring of formula (6), wherein R ₆₁ and R ₆₂ are 2,2-propylidene groups.

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

The compound represented by is mentioned.

As a diamine component giving the repeating unit of General formula (I) where Y _<1> is a divalent group which has an aromatic ring, for example, p-phenylenediamine, m-phenylenediamine, benzidine, and 3,3'-diamino -Biphenyl, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-bis(trifluoromethyl)benzidine, m-tolidine, 4,4'-diaminobenzanilide, 3,4 '-diaminobenzanilide, N,N'-bis(4-aminophenyl)terephthalamide, N,N'-p-phenylenebis(p-aminobenzamide), 4-aminophenoxy-4-diamino Benzoate, bis(4-aminophenyl)terephthalate, biphenyl-4,4'-dicarboxylic acid bis(4-aminophenyl)ester, p-phenylenebis(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, octafluorobenzidine, 3,3 '-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl , 2,4-bis (4-aminoanilino) -6-amino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-methylamino-1,3,5 -Triazine, 2,4-bis(4-aminoanilino)-6-ethylamino-1,3,5-triazine, 2,4-bis(4-aminoanilino)-6-anilino-1 ,3,5-triazine can As the diamine component giving the repeating unit of the general formula (I) where Y ₁ is a divalent group having an aromatic ring containing a fluorine atom, for example, 2,2'-bis(trifluoromethyl)benzidine, 3, 3'-bis (trifluoromethyl) benzidine, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, and 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. As a further preferred diamine compound, 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. A diamine component may be used independently and may also be used in combination of multiple types.

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

As a bivalent group which has an alicyclic structure, the following are mentioned, for example.

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

As V ₁ and V ₂ , specifically, a direct bond and a divalent group represented by the above formula (5) are exemplified.

As the divalent group having an alicyclic structure, since it is possible to achieve both high heat resistance and a low linear thermal expansion coefficient of the obtained polyimide, the following ones are particularly preferred.

As a divalent group which has an alicyclic structure, the following are preferable especially.

As a diamine component giving the repeating unit of General formula (I) where Y _<1> is a divalent group which has an alicyclic structure, 1, 4- diamino cyclohexane, 1, 4- diamino-2-methylcyclohexane, for example , 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-butylcyclo Hexane, 1,2-diaminocyclohexane, 1,3-diaminocyclobutane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, diaminobicycloheptane, Diaminomethylbicycloheptane, diaminooxybicycloheptane, diaminomethyloxybicycloheptane, isophoronediamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis(aminocyclohexyl)methane, bis(amino Cyclohexyl) isopropylidene, 6,6'-bis (3-aminophenoxy) -3,3,3', 3'-tetramethyl-1,1'-spirobiindan, 6,6'-bis( and 4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindan. A diamine component may be used independently and may also be used in combination of multiple types.

Any of non-aliphatic aliphatic tetracarboxylic acids (particularly dianhydrides) and/or aliphatic diamines can be used as the tetracarboxylic acid component and diamine component that give the repeating unit represented by the general formula (I) above. However, the content thereof is preferably 30 mol% or less or less than 30 mol%, more preferably 20 mol% or less, still more preferably 10 mol% based on 100 mol% of the total of the tetracarboxylic acid component and the diamine component. It is preferable that it is below (including 0%).

In a preferred embodiment of the present invention, X ₁ of the general formula (I) is more than 60%, more preferably 70 mol% or more, more preferably 80% of the total repeating units of the repeating unit having a tetravalent group having an alicyclic structure. mol% or more, more preferably 90 mol% or more, particularly preferably 100 mol%. When the alicyclic structure is less than 100%, X ₁ is preferably a tetravalent group having an aromatic ring in the remaining portion. The tetravalent group having a preferable alicyclic structure and the tetravalent group having an aromatic ring are as described above. 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 is a 2 group having an alicyclic structure The content of the repeating unit represented by the formula (I) as a valent group is preferably 50 mol% or less, more preferably 30 mol% or less or less than 30 mol%, and more preferably 10 mol% or less with respect to all repeating units. it is desirable

In one preferred embodiment of the present invention, a polyimide precursor that provides a polyimide film having a relatively large elastic modulus is preferred. When a polyimide film is produced using a polyimide precursor that does not contain a siloxane compound (for example, 10 μm thick), it is preferably 3.0 GPa or more, more preferably 3.5 GPa or more, and still more preferably 4.0 GPa. It is preferable to apply to providing the above polyimide film.

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

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

A structure in which R ₆₁ to R ₆₈ is a direct bond, -CO-, -NHCO-, -CONH-, -COO- or -OCO- is preferable. Examples of the diamine compound imparting this structure include p-phenylenediamine, 4,4'-diaminobenzanilide, 3,3'-bis(trifluoromethyl)benzidine, and m-tolidine. .

In this embodiment, Y ₁ of such a rigid structure is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, still more preferably, with respect to 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 preferably 40 mol% or less, more preferably 30 mol% or less, and still more preferably 30 mol% or less with respect to the total Y ₁ It is 20 mol% or less.

In this embodiment, X ₁ derived from the tetracarboxylic acid component may be a tetravalent contribution having an aromatic ring or a tetravalent contribution having an alicyclic structure, but since a highly transparent polyimide is obtained, X ₁ is fluorine. A tetravalent group having an aromatic ring containing or a tetravalent group having an alicyclic structure is preferable. As the tetravalent group having an alicyclic structure, a group represented by the above formula (10) is preferred, and a group represented by the formula (11) is more preferred. For example, in order to adjust physical properties, X ₁ may have other structures, but preferably 40 mol% or less, more preferably 30 mol% or less, still more preferably 20 mol% with respect to the total X ₁ below

A polyimide precursor can be manufactured from the said 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 of 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 as And the polyimide precursor can be easily manufactured for each of these classifications by the following manufacturing methods. However, the manufacturing method of the polyimide precursor used by this invention is not limited to the following manufacturing method.

1) Polyamic acid

The polyimide precursor contains tetracarboxylic dianhydride as a tetracarboxylic acid component and a diamine component in approximately equal moles in a solvent, preferably in a molar ratio of diamine component to tetracarboxylic acid component [number of moles of diamine component/tetracarboxylic acid]. The number of moles of the components] is preferably 0.90 to 1.10, more preferably 0.95 to 1.05, and reacted while suppressing imidation at a relatively low temperature of, for example, 120 ° C. or less, to obtain a suitable polyimide precursor solution. can

Although not limited, more specifically, diamine is dissolved in an organic solvent or water, and tetracarboxylic dianhydride is gradually added to the solution while stirring, at a temperature of 0 to 120°C, preferably 5 to 80°C. By stirring for 1 to 72 hours in the range, a polyimide precursor is obtained. When reacting at 80°C or higher, the molecular weight fluctuates depending on the temperature history at the time of polymerization, and imidation proceeds with heat, so there is a possibility that a polyimide precursor cannot be stably produced. The order of addition of diamine and tetracarboxylic dianhydride in the above production method is preferred because the molecular weight of the polyimide precursor tends to increase. Moreover, it is also possible to reverse the addition order of the diamine and tetracarboxylic dianhydride of the said manufacturing method, and since a precipitate is reduced, it is preferable. When water is used as the solvent, it is preferably 0.8 times the amount of imidazoles such as 1,2-dimethylimidazole or carboxyl groups of polyamic acid (polyimide precursor) that generates bases such as triethylamine. It is preferable to add in an amount equal to or more than equivalent.

2) Polyamic acid ester

A diester dicarboxylic acid is obtained by reacting tetracarboxylic dianhydride with any alcohol, and then reacted with a chlorinating reagent (thionyl chloride, oxalyl chloride, etc.) to obtain a diester dicarboxylic acid chloride. A polyimide precursor is obtained by stirring this diester dicarboxylic acid chloride and diamine in the range of -20 to 120°C, preferably -5 to 80°C for 1 to 72 hours. When reacting at 80°C or higher, the molecular weight fluctuates depending on the temperature history at the time of polymerization, and imidation proceeds with heat, so there is a possibility that a polyimide precursor cannot be stably produced. In addition, a polyimide precursor can be easily obtained also by subjecting diester dicarboxylic acid and diamine to dehydration condensation using a phosphorus-based condensing agent, a carbodiimide condensing agent, or the like.

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

3) polyamic acid silyl ester (indirect method)

In advance, diamine and a silylating agent are reacted to obtain a silylated diamine. If necessary, silylated diamine is purified by distillation or the like. Then, the silylated diamine is dissolved in the dehydrated solvent, and tetracarboxylic dianhydride is gradually added while stirring, and stirred at 0 to 120°C, preferably 5 to 80°C for 1 to 72 hours. , a polyimide precursor is obtained. When reacting at 80°C or higher, the molecular weight fluctuates depending on the temperature history at the time of polymerization, and imidation proceeds with heat, so there is a possibility that a polyimide precursor cannot be stably produced.

4) Polyamic acid silyl ester (direct method)

1) A polyimide precursor is obtained by mixing the polyamic acid solution obtained by this method and a silylating agent, and stirring for 1 to 72 hours in a range of 0 to 120°C, preferably 5 to 80°C. When reacting at 80°C or higher, the molecular weight fluctuates depending on the temperature history at the time of polymerization, and imidation proceeds with heat, so there is a possibility that a polyimide precursor cannot be stably produced.

As the silylating agent used in the methods 3) and 4), it is preferable to use a silylating agent that does not contain chlorine because it is not necessary to purify the silylated polyamic acid or the obtained polyimide. Examples of the silylating agent containing no chlorine atom include N,O-bis(trimethylsilyl)trifluoroacetamide, N,O-bis(trimethylsilyl)acetamide, and hexamethyldisilazane. Since it does not contain a fluorine atom and is low cost, N,O-bis (trimethylsilyl) acetamide and hexamethyldisilazane are particularly preferable.

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

The solvent used when manufacturing a polyimide precursor is water, but, for example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2- An aprotic solvent such as pyrrolidone, 1,3-dimethyl-2-imidazolidinone, or dimethyl sulfoxide is preferred, and any kind of solvent can be used without any problem as long as the raw material monomer component and the resulting polyimide precursor are dissolved. Since it can be used, the structure is not particularly limited. As the solvent, water, amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and N-ethyl-2-pyrrolidone, γ-butyrolactone, γ - Cyclic ester solvents such as valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, and α-methyl-γ-butyrolactone, carbonates such as ethylene carbonate and propylene carbonate Solvents, glycol solvents such as triethylene glycol, m-cresol, p-cresol, 3-chlorophenol, phenolic solvents such as 4-chlorophenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, Sulfolane, dimethyl sulfoxide and the like are preferably employed. In addition, other common organic solvents, namely phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cell Rosolve acetate, butyl cellosolve acetate, tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, Methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, turpentine, mineral spirits, petroleum naphtha solvents and the like can also be used. In addition, a solvent can also be used combining multiple types.

Although it does not specifically limit in manufacture of a polyimide precursor, A monomer and a solvent are injected|thrown-in and reaction is performed at the density|concentration at which the solid content concentration (polyimide conversion mass concentration) of a polyimide precursor becomes, for example, 5-45 mass %.

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

As the imidation 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 precursor (polyamic acid, polyamic acid ester, polyamic acid silyl ester) obtained by the above method has a low imidation rate. These can be imidated in a solution (thermal imidation, chemical imidation), imidation can be advanced, and a desired imidation rate can be adjusted. For example, a polyimide precursor in which imidation has progressed can be obtained by stirring a polyamic acid solution in a range of, for example, 80 to 230 ° C., preferably 120 to 200 ° C., for example, for 1 to 24 hours. . When the polyimide is solvent soluble, the polyimide obtained by pouring the reaction mixture after the imidation reaction into a poor solvent to precipitate the polyimide, or a solution of a polyimide precursor (low imidation rate) (if necessary, an imidation catalyst or dehydrating agent) For example, a polyimide obtained by casting a carrier substrate, heat-treating, drying, and imidizing (thermal imidation, chemical imidation) is dissolved in a solvent and used as a polyimide precursor for film production. can also

<Siloxane compound>

The siloxane compound used in the present invention is required to have a function capable of reducing residual stress at the interface of the polyimide film/substrate 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 be a homogeneous solution without turbidity, and that the polyimide film be obtained as a homogeneous film without turbidity.

In one embodiment of the present invention, a phenyl group-containing linear siloxane compound is preferable, and a refractive index of 1.54 or more is particularly preferable. The phenyl group is preferably bonded to the terminal Si. The siloxane compound is a silanol group (Si-OH), and a group that becomes a silanol group by hydrolysis, such as an alkoxysilyl group (Si-OR, R is an alkyl group), an aryloxysilyl group (Si-OAr, Ar is aryl group), an acyloxysilyl group (Si-OCOR, R is an alkyl group), a ketoxime group (Si-ON=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 each independently a hydrogen atom or 1 to 10 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, each of R ₄ and R ₅ may represent a different group in a plurality of occurrences, provided that the molecule contains at least one phenyl group. , At least one of R ₁ to R ₈ represents a phenyl group.

Preferably, at least one, preferably two or more of R ₁ to R ₃ and R ₆ to R ₈ are phenyl groups, more preferably one or more (preferably two or more) of R ₁ to R ₃ are Phenyl group Also, at least one (preferably two or more) of R ₆ to R ₈ is a phenyl group. In this case, it is also preferable that at least one of R ₄ and R ₅ is a phenyl group. Moreover, in a preferable embodiment, the refractive index of the compound represented by formula (S) is 1.54 or more.

When the siloxane compound is used, a uniform polyimide precursor composition without turbidity is obtained, a uniform polyimide film without turbidity is obtained, and a sufficient effect in reducing residual stress is obtained. In addition, even if the siloxane compound is added, the decrease in the 1% weight loss temperature and 5% weight loss temperature of the obtained film is very small (see Examples), so that the polyimide film volatilizes even when reheated for the formation of barrier films, elements, etc. Low emission of water/degradables. Therefore, when the polyimide precursor composition of the present invention is used, contamination of the flexible electronic device manufacturing equipment is prevented, and problems such as swelling of the film/inorganic film do not occur, so that the semiconductor element is not adversely affected. A flexible electronic device can be manufactured with good yield.

On the other hand, in the polyimide precursor composition to which cyclic siloxane is added described in Patent Document 7 (Japanese Unexamined Patent Publication No. 2019-203117), cyclic siloxane, a hydrolyzate thereof, a modified product thereof, etc. remain in the film after film formation, and the film On reheating, there is a high emission of volatiles/decomposition products. 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 will occur.

<Formulation of polyimide precursor composition>

The polyimide precursor composition used in the present invention contains at least one polyimide precursor, at least one siloxane compound, and a solvent.

The content of the siloxane compound can be adjusted in consideration of the effect of reducing residual stress between the polyimide film and the substrate. In general, if the amount is too small, the residual stress reduction effect is not sufficient. On the other hand, if the amount is too large, not only is it useless, but also turbidity occurs in the obtained polyimide film, 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 or more with respect to 100 parts by mass in terms of polyimide of the polyimide precursor. and usually less than 30 parts by weight, preferably 28 parts by weight or less, more preferably 25 parts by weight or less, still more preferably 23 parts by weight or less.

As the solvent, those described above as the solvent used when manufacturing the polyimide precursor can be used. Usually, although the solvent used when manufacturing a polyimide precursor can be used as it is, that is, as a polyimide precursor solution, you may use it after diluting or concentrating as needed. The concentration of the polyimide precursor is not particularly limited, but is usually 5 to 45% by mass in terms of polyimide conversion mass concentration (solid content concentration). It is preferable that the siloxane compound is dissolved and present in the polyimide precursor composition. Since a uniform and transparent polyimide film is usually not obtained when it is not completely dissolved in the polyimide precursor composition and there is turbidity, the type and/or amount of the siloxane compound is determined from this point of view. Here, the mass in terms of polyimide is the mass when all of the repeating units are completely imidized.

Although the viscosity (rotational viscosity) of the polyimide precursor of the present invention is not particularly limited, 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 preferably 0.01 to 1000 Pa·sec. , more preferably 0.1 to 100 Pa·sec. Further, thixotropic properties may be imparted as necessary. With a viscosity within the above range, it is easy to handle when coating or forming a film, and since repelling is suppressed and the leveling property is excellent, a good film can be obtained.

The polyimide precursor composition of the present invention, if necessary, a chemical imidation agent (acid anhydrides such as acetic anhydride, amine compounds such as pyridine and isoquinoline), antioxidants, ultraviolet absorbers, fillers (inorganic particles such as silica, etc. ), dyes, pigments, coupling agents such as silane coupling agents, primers, flame retardants, antifoaming agents, leveling agents, rheology control agents (flow aids), and the like.

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

<Imidazole compound>

The polyimide precursor composition may contain an imidazole compound. By containing imidazole, at least one of transparency, thickness direction retardation, mechanical properties, and thermal properties may be improved, for example. Examples of the imidazole compound include, but are not particularly limited to, 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, benzimidazole, and the like. have. From the viewpoint of stability of the polyimide precursor composition and improvement of mechanical properties, it is particularly preferred 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 effect of addition and the stability of the polyimide precursor composition. The amount of the imidazole compound is preferably from more than 0.01 mol to less than 1 mol with respect to 1 mol of the repeating unit of the polyimide precursor. If the content of the imidazole compound is too small, for example, mechanical properties such as elongation at break may be reduced. On the other hand, if the content of the imidazole compound is too large, the storage stability of the polyimide precursor composition may deteriorate. .

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 still more preferably 0.8 mol or less, still more preferably 0.8 mol or less, per 1 mol of the repeating unit. More preferably, it is 0.6 mol or less, and still more preferably 0.4 mol or less.

<<Manufacture of polyimide film/substrate laminate and flexible electronic device>>

The polyimide film/substrate laminate of the present invention includes (a) a step of applying a polyimide precursor composition onto a substrate, (b) heat treatment of the polyimide precursor on the substrate, and forming a polyimide film on the substrate. It can be manufactured by the process of manufacturing this laminated laminate (polyimide film/substrate laminate). In the method for manufacturing a flexible electronic device of the present invention, the polyimide film/substrate laminate manufactured in the steps (a) and (b) is used in an additional step, that is, (c) on the polyimide film of the laminate. It has the process of forming at least 1 layer chosen from a conductor layer and a semiconductor layer, and (d) process of peeling the said base material and the said 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 terms 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 among the terms 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 substrate, imidized and desolvated by heat treatment to form a polyimide film, and a laminate of the substrate and the polyimide film (polyimide film/ substrate laminate) is obtained.

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

In the present invention, a glass substrate is particularly preferred. As for the glass substrate, a flat, smooth, and large-area glass substrate has been developed and can be easily obtained. Since the problem of warpage becomes more prominent especially as the substrate becomes larger, and the glass substrate is relatively prone to warpage also in terms of rigidity, the subject in the case of using a glass substrate can be solved by applying the present invention. The thickness of the plate-shaped substrate 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 (longer side when rectangular) is, for example, about 100 mm to about 4000 mm, preferably about 200 mm to about 3000 mm, more preferably 300 mm. It is about 2500 mm.

Substrates 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, but examples thereof include slit coating, die coating, blade coating, spray coating, inkjet coating, nozzle coating, spin coating, and screen printing. Conventionally known methods, such as a method, a bar coater method, and an electrodeposition method, are mentioned.

In step (b), the polyimide precursor composition is subjected to heat treatment on the substrate, and converted to a polyimide film to obtain a polyimide film/substrate laminate. The heat treatment conditions are not particularly limited, for example, after drying at 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, and more Preferably, it is preferable to process at 250 ° C to 500 ° C. The heat treatment conditions in the case of using the polyimide solution are not particularly limited, but the maximum heating temperature is, for example, 100°C to 600°C, preferably 150°C or higher, more preferably 200°C or higher, and also preferably is 500°C or less, more preferably 450°C or less.

The thickness of the polyimide film is preferably 1 μm or more, more preferably 2 μm or more, and still more preferably 5 μm or more. When the thickness is less than 1 μm, the polyimide film cannot maintain sufficient mechanical strength, and when used as a flexible electronic device substrate, for example, it may not be able to withstand stress and break. In addition, the thickness of the polyimide film is preferably 100 μm or less, more preferably 50 μm or less, still more preferably 20 μm or less. When the thickness of a polyimide film becomes thick, thinning of a flexible device may become difficult. The thickness of the polyimide film is preferably 2 to 50 μm in order to achieve further thinning 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, when measured as a film having a thickness of 10 μm. Preferably it is 80% or more.

In the present invention, the polyimide film/substrate laminate is characterized by small warpage. Details of the measurement will be explained in the section of <<evaluation of warpage, measurement of residual stress>> described later, but in one embodiment, the characteristics of a polyimide film are measured in a polyimide film/silicon substrate (wafer) laminate. When evaluated by the residual stress between the polyimide film and the silicon substrate of , the residual stress is preferably 100 MPa or less, more preferably 95 MPa or less, in another embodiment preferably 73 MPa or less, and in another embodiment preferably Preferably it is 60 MPa or less, in another embodiment it is 40 MPa or less, and in another 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, Eagle-XG (registered trademark) manufactured by Corning Corporation of the 6th generation (glass substrate, vertical size: 1500 mm, horizontal size: 1850 mm, diagonal size: 2382 mm, thickness: 0.5 mm, modulus of elasticity: 73.6 GPa) In terms of , the magnitude of the warpage of the 10 μm thick polyimide film/glass substrate laminate is, in diagonal size, preferably 200 mm or less, more preferably 195 mm or less, and in other embodiments, preferably 150 mm Hereinafter, in another embodiment, it is preferably 120 mm or less, in another embodiment, 80 mm or less, and in another embodiment, it is less than 64 mm, more preferably less than 58 mm. Here, the magnitude of the warpage is the distance from the flat surface to the periphery when the laminate is placed on a flat surface as shown in FIG. 1 .

In one embodiment of the present invention, the elongation at break of the polyimide film having a thickness of 10 μm is preferably 10% or more.

In another 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, and still more preferably 200 MPa or more. For the breaking strength, a value obtained from a film having a thickness of about 5 to 100 µm can be used, for example.

It is particularly preferable that the above desirable properties relating to the polyimide film and the laminate are simultaneously satisfied.

The polyimide film in the polyimide film/substrate 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 substrate, the second layer may be laminated to form the flexible electronic device substrate. What has at least an inorganic film is preferable, and what functions as a barrier layer of water vapor, oxygen (air), etc. especially is preferable. As the water vapor barrier layer, for example, silicon nitride (SiN _x ), silicon oxide (SiO _x ), silicon oxynitride (SiO _x N _y ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), zirconium oxide ( and an inorganic film containing an inorganic substance selected from the group consisting of metal oxides such as ZrO ₂ ), metal nitrides, and metal oxynitrides. In general, as a film formation method of these thin films, physical vapor deposition methods such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition methods (chemical vapor deposition methods) such as plasma CVD and catalytic chemical vapor deposition (Cat-CVD) etc. are known. This 2nd layer can also be made into multiple layers.

When the second layer is a plurality of layers, it is also possible to combine a resin film and an inorganic film, for example, a three-layer structure of barrier layer/polyimide layer/barrier layer on the polyimide film in the polyimide film/substrate laminate. Examples of forming a and the like can be given.

In step (c), using the polyimide/substrate laminate obtained in step (b), a conductor layer and At least one layer selected from semiconductor layers is formed. These layers may be directly formed on a polyimide film (including a layer obtained by laminating a second layer), or may be formed on a layered layer of another layer required for a device, that is, indirectly.

An appropriate conductor layer and (inorganic, organic) semiconductor layer are selected for the conductor layer and/or semiconductor layer according to the elements and circuits required by the target electronic device. In the step (c) of the present invention, when forming at least one of the conductor layer and the semiconductor layer, 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 move to step (d) immediately after step (c), and after forming at least one layer selected from a conductor layer and a semiconductor layer in step (c), and further forming a device structure, You may proceed to (d).

When manufacturing a TFT liquid crystal display device as a flexible device, for example, on a polyimide film having an inorganic film formed on the entire surface as necessary, for example, a TFT made of metal wiring, amorphous silicon or polysilicon, a transparent pixel electrode form A TFT includes, for example, a gate metal layer, a semiconductor layer such as an amorphous silicon film, a gate insulating layer, wirings connected to pixel electrodes, and the like. On top of this, a structure necessary for a liquid crystal display can also be formed by a known method. Moreover, you may form a transparent electrode and a color filter on a polyimide film.

In the case of manufacturing an organic EL display, for example, a transparent electrode, a light emitting layer, a hole transporting layer, an electron transporting layer, etc. are additionally formed on a polyimide film on which an inorganic film is formed on the entire surface, for example, as necessary. can

Since the polyimide film preferred in the present invention is excellent in various properties such as heat resistance and toughness, the method for forming circuits, elements, and other structures necessary for the device is not particularly limited.

Next, in step (d), the substrate and the polyimide film are separated. The peeling method may be a mechanical peeling method of physically peeling by applying an external force, or a so-called laser peeling method of peeling by irradiating a laser beam from the base material surface.

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

<<Evaluation of warpage, measurement of residual stress>>

FIG. 1 schematically shows the warpage of a polyimide film/substrate laminate in which a polyimide film 1 is formed on a substrate 2 . The warpage of the polyimide film/substrate laminate differs depending on the modulus of elasticity of the base material. Moreover, even if it is the same type of base material, the "value of warp" differs according to thickness and size.

Further, according to the study of the present inventors, since polyimide elongates due to moisture absorption, the degree of warping of the polyimide film/substrate laminate differs depending on the dry state of the polyimide film. In particular, when evaluation is performed in the environmental atmosphere and environmental temperature, the polyimide film absorbs moisture and the warpage of the laminate tends to be reduced. Moreover, since conveyance and storage are also carried out in a dry atmosphere, the warpage of the layered product increases. That is, warpage, which is a problem in manufacturing electronic devices, cannot be accurately evaluated in measurements in the environmental atmosphere and environmental temperature. Therefore, it is preferable to measure warpage (or residual stress) in a dry state of the polyimide film. Therefore, it is conceivable to place the whole measuring device in a dry atmosphere, but it is impractical because the device becomes large-scale and it takes time for the polyimide film to be in an equilibrium state.

One aspect of the present invention made to solve this problem is,

(1) a step of preparing a polyimide film/standard substrate laminate in which a polyimide film is formed on a standard substrate;

(2) a step of measuring the radius of curvature (curvature) of the polyimide film/reference substrate laminate at a plurality of measurement temperatures of 80°C or higher;

(3) a step of calculating the residual stress between the polyimide film and the standard substrate in the polyimide film/standard substrate laminate at the measured temperature based on the measured radius of curvature (warpage); and

(4) Step of obtaining the residual stress at a predetermined temperature based on the residual stress at a plurality of measurement temperatures

It relates to a method for evaluating residual stress of a polyimide film/substrate laminate having.

In step (1), the reason for using the "standard substrate" is that the warpage of the polyimide film/substrate laminate differs depending on the substrate as described above, so in order to evaluate it as "polyimide film characteristics", measurement This is because it is preferable to use a base material (hereinafter referred to as a standard base material) suitable for the above. Since the main object of the present invention is to evaluate the warpage of the polyimide film / glass substrate laminate, it is also possible to perform the following measurement and evaluation using a glass substrate, but in the examples of this application, as a standard substrate, a predetermined thickness A silicon substrate (wafer) of was used. This is because the surface reflectance of the silicon substrate is large, and warpage can be easily measured by an optical method. In particular, it is not limited to a silicon substrate, and can be selected in consideration of a measuring device or method.

A polyimide film/substrate laminate is prepared according to the method for producing a polyimide film/substrate laminate described above, (a) a polyimide precursor composition is applied on a reference substrate, and (b) a polyimide precursor is applied on the reference substrate. is heat-treated, and a polyimide film is laminated on a standard substrate to manufacture, and this can be used as a measurement sample.

Next, in step (2), warpage is measured at a relatively high temperature at 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 particularly preferably 100°C or higher. The upper limit of the temperature is up to the Tg of the polyimide, and the decomposition temperature is the upper limit when the Tg is not observed. This is because, although the change in elastic modulus is small up to Tg, the elastic modulus changes greatly when Tg is exceeded, so it is not suitable as a measurement point for extrapolation to, for example, room temperature in the next step (4). Usually, it is 250 degrees C or less, Preferably it is 200 degrees C or less. Generally, a range of 100°C to 200°C, for example 100°C to 150°C, is preferred.

Therefore, in the method of this aspect, what is necessary is just to measure the warp in a some temperature different from this temperature range, preferably in 3 or more different temperature points, and more preferably in 4 or more different temperature points. It also depends on the measuring method and measuring device, but in order to increase the measurement accuracy, it is also preferable to measure a plurality of times at the same temperature, for example, 3 times or more, for example, about 10 times or more, and obtain an average value.

As the environment of the measurement method, the measurement device may be measured in a dry environment such as in dry air or in an inert gas. °C, relative humidity of 30 to 60%), since the measurement sample and its surroundings become the high temperature as described above, the measurement sample is placed in an extremely low-humidity environment.

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

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

here,

E/(1-ν): biaxial modulus of elasticity (Pa) of the substrate (reference substrate: silicon wafer);

1.805E11Pa in (100) silicon;

h: thickness of substrate (m)

t: thickness of polyimide film (m)

R: radius of curvature of the measurement sample (m)

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 determined based on the residual stress at a plurality of measurement temperatures calculated in step (3). The predetermined temperature is not a specially determined temperature, but a target temperature (temperature-of-interest) that can be selected according to the purpose. For example, 23°C may be employed.

In the example of FIG. 2 , residual stresses obtained from five different measured temperatures of 100° C. or higher are plotted on a graph with temperature on the abscissa axis and residual stress on the ordinate 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. can be saved

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 substrate).

In addition, in order to estimate the curvature of the polyimide film/objective base material laminate using the target base material (eg glass substrate) actually used for device manufacture, it is performed as follows. First, the curvature radius R of the warp occurring in the polyimide film/target substrate laminate is obtained using Equation 2 below.

here,

E: Tensile modulus of elasticity of the target substrate (Pa)

h: thickness of the target substrate (m)

t: thickness of polyimide film (m)

S: Residual stress (Pa) at 23°C (predetermined temperature) determined for a standard substrate

R: radius of curvature (m)

The radius of curvature calculated from Equation 2 can be substituted into Equation 3, and the size of the warp W shown in FIG. 1 can be calculated and estimated.

here,

L: the length (m) of the target description, for example, the diagonal distance, etc.

W: magnitude of deflection

According to the evaluation method of the residual stress of the polyimide film/substrate laminate of the present embodiment as described above, since the influence due to moisture absorption of the polyimide film can be eliminated, the following advantageous effects are obtained. First, when the polyimide film in the laminate is in a moisture absorption state, the warpage is relatively small and often different from the warpage that occurs in the actual process. However, this embodiment enabled appropriate evaluation. In addition, it became possible to evaluate stably without being affected by the measurement environment. In addition, since the difference in deflection between the moisture absorption state and the dry state varies depending on the composition of the polyimide (hygroscopicity differs depending on the composition), relative evaluation is also meaningless in the moisture absorption state. have been able to

Example

Hereinafter, the present invention is further explained by examples and comparative examples. In addition, this invention is not limited to the following example.

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

<Evaluation of polyimide precursor composition (varnish)>

[Varnish uniformity]

The varnish containing the siloxane compound was visually observed, and when it was in a uniform state, it was rated as ○, and when it was in a cloudy or phase-separated non-uniform state, it was rated as ×.

<Evaluation of polyimide film>

[Polyimide film uniformity]

The polyimide film was visually observed, and when it was in a uniform state, it was rated as ○, and when it was cloudy, it was rated as ×.

[400nm light transmittance]

The light transmittance at 400 nm of a polyimide film having a film thickness of about 10 µm was measured using a spectrophotometer for ultraviolet and visible light/V-650DS (manufactured by Nippon Bunko).

[Elastic modulus, elongation at break, strength at break]

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

[Coefficient of Linear Thermal Expansion (CTE)]

A polyimide film with a film thickness of about 10 μm was cut into a rectangle with a width of 4 mm to make a test piece, using TMA / SS6100 (manufactured by SII Nano Technology Co., Ltd.), chuck length 15 mm, load 2 g, temperature increase rate 20 ° C. The temperature was raised to 500 ° C. / min. 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 with a film thickness of about 10 μm as a test piece, the temperature was raised from 25° C. to 600° C. at a heating rate of 10° C./min in a nitrogen stream using a calorimeter measuring device (Q5000IR) manufactured by TA Instruments. From the obtained weight curve, the 1% and 5% weight loss temperatures were determined.

[Thickness direction retardation (R _th ) of the film]

A polyimide film having a thickness of 10 μm was used as a test piece, and phase difference measurement of the film was performed using a retardation measuring device (KOBRA-WR) manufactured by Oji Keisokugi Co., Ltd. at an angle of incidence of 40°. From the obtained retardation, the retardation in the thickness direction of the film having a film thickness of 10 μm was determined.

<Evaluation of polyimide film/substrate laminate>

The warpage of the polyimide film/silicon wafer laminate was measured using FLX-2320 manufactured by KLA Tencor. The radius of curvature of the silicon wafer alone is measured in advance in an environment of 23°C and 50% RH. After that, a polyimide film is formed on the silicon wafer. The radius of curvature of the laminate was measured, and the residual stress was calculated. In addition, when measuring the radius of curvature of the polyimide film/standard substrate laminate in a heated state, the radius of curvature of the silicon wafer alone was also measured at the same temperature.

<Raw material>

The abbreviation, 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

BAPB: 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: Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2"-norbornane-5,5",6,6"-tetracarboxylic dianhydride

DNDAxx: (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2t,3t,6c,7c-tetracarboxylic dianhydride

PMDA-H: cyclohexanetetracarboxylic 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 dianhydride

PMDA: pyromellitic dianhydride

[menstruum]

NMP: N-methyl-2-pyrrolidone

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

[Table 1-1]

[Table 1-2]

[Table 1-3]

<Example 1>

[Preparation of Polyimide Precursor Composition]

In a reaction vessel purged with nitrogen gas, 0.91 g (4 mmol) of DABAN, 0.54 g (5 mmol) of PPD, and 0.37 g (1 mmol) of BAPB were placed, N-methyl-2-pyrrolidone was added, and the total mass of the input monomers ( Total of diamine component and carboxylic acid component) added 29.73g of the quantity used as 16 mass %, and stirred at 50 degreeC for 1 hour. To this solution, 3.84 g (10 mmol) of CpODA was slowly added. It stirred at 70 degreeC for 4 hours, and obtained the 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 to obtain a uniform and viscous polyyi. A mid precursor composition was obtained.

[Manufacture of polyimide film/substrate laminate]

In order to manufacture a polyimide film/substrate laminate for polyimide film evaluation, a 6-inch Eagle-XG (registered trademark) manufactured by Corning Co., Ltd. (500 μm thick) was used as a glass substrate. A polyimide precursor composition is applied on a glass substrate by a spin coater, and heated as it is on the glass substrate from room temperature to 415° C. in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize the polyimide film/substrate. A laminate was obtained. The laminate was immersed in hot water to peel the polyimide film from the glass substrate, and after drying, the properties of the polyimide film were evaluated. The film thickness of the polyimide film is about 10 μm.

[Production of Polyimide Film/Base Substrate Laminate]

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

For the obtained polyimide film/reference substrate laminate, the curvature radii of warpage were measured at temperatures of 150°C, 140°C, 130°C, 120°C, and 110°C. In each temperature, it measured 20 times and calculated|required the average value. From the obtained radius of curvature, the residual stress at each temperature was calculated, and the residual stress at 23°C was obtained from a linear approximation by the least square method. In addition, the residual stress was determined from the radius of curvature of the warp measured in an environment of 23°C and 50% RH without heating. These results are shown in Table 2. In addition, a sixth generation glass substrate (purpose substrate) (Eagle-XG (registered trademark), vertical size: 1500 mm, horizontal size: 1850 mm, diagonal size: 2382 mm, thickness: 0.5 mm, modulus of elasticity: 73.6 GPa) is used. Thus, the value of the warpage that occurs when a polyimide film/substrate laminate is produced is calculated and shown in Table 2 as well.

<Examples 2 to 15 (excluding Examples 6 and 9), Comparative Examples 1 to 21 (excluding Comparative Examples 11 and 14)>

Polyimide was prepared 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 in Example 1. A film/standard substrate laminate was prepared, warpage of the laminate was measured in the same manner as in Example 1, and residual stress at 23°C was determined. The results are shown in Tables 2 to 5. Similarly, the values of warpage estimated for the polyimide film/substrate laminate using the 6th generation glass substrate (Eagle-XG (registered trademark) 500 μm thickness, elastic modulus: 73.6 GPa) are combined with Tables 2 to 5 indicate

<Example 6>

[Preparation of Polyimide Precursor Composition]

In a reaction vessel purged with nitrogen gas, 2.25 g (9.9 mmol) of DABAN and 0.04 g (0.1 mmol) of BAPB were placed, N-methyl-2-pyrrolidone was added, and the total mass of the input monomers (diamine component and carboxylic acid component) was added. 32.19 g of an amount of 16% by mass) was added, and the mixture was stirred at 50°C for 1 hour. To this solution, 3.84 g (10 mmol) of CpODA was slowly added. It stirred at 70 degreeC for 4 hours, and obtained the 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 concentration of 20% by mass of 2-phenylimidazole. The imidazole compound solution 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 stirred at room temperature for 3 hours to obtain a uniform and viscous product. A polyimide precursor composition was obtained.

HIVAC-F-5 as a siloxane compound is added to the polyimide precursor solution synthesized above in an amount of 5.0 parts by mass based on 100 parts by mass of the solid content after heating the polyimide precursor to become polyimide, and mixing; The mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide precursor composition. Using the obtained polyimide precursor composition, a polyimide film/reference substrate laminate was produced and evaluated 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.

<Comparative Example 11>

A polyimide film/reference substrate laminate was prepared 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]

In a reaction vessel purged with nitrogen gas, 1.82 g (8 mmol) of DABAN and 0.58 g (2 mmol) of TPE-Q were placed, and the total mass of charged monomers (total sum 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 slowly added to this solution. It stirred at 70 degreeC for 4 hours, and obtained the uniform and viscous polyimide precursor solution. Then, it stirred at 120 degreeC for 6 hours and obtained the partially imidated polyimide precursor solution whose imidation rate is 77 %.

HIVAC-F-5 as a siloxane compound is added to the polyimide precursor solution synthesized above in an amount of 10.0 parts by mass based on 100 parts by mass of the solid content after heating the polyimide precursor to become polyimide, and mixing; The mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide precursor composition. Using the obtained polyimide precursor composition, a polyimide film/standard substrate laminate was produced and evaluated 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.

<Comparative Example 14>

Except for not adding the siloxane compound, a polyimide film/reference substrate laminate was produced and evaluated in the same manner as in Example 9.

[Table 2]

[Table 3]

[Table 4]

[Table 5]

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

Claims (19)

A polyimide precursor (provided that the polyimide precursor is not imidized or is partially or completely imidized);
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 and less than 30 parts by mass based on 100 parts by mass in terms of polyimide of the polyimide precursor, and
menstruum
Polyimide precursor composition characterized in that it contains. The composition according to claim 1, wherein the siloxane compound does not have a silanol group or a group that becomes a silanol group upon hydrolysis. The composition according to claim 1 or 2, wherein a phenyl group is bonded to the terminal Si. A polyimide precursor (provided that the polyimide precursor is not imidized or is partially or completely imidized);
A phenyl group-containing linear siloxane compound represented by the following formula (S) in an amount of more than 0.5 parts by mass and less than 30 parts by mass based on 100 parts by mass in terms of polyimide of the polyimide precursor, and
menstruum
Polyimide precursor composition characterized in that it contains.

(Wherein, n is an integer of 0 to 10, R ₁ to R ₈ are each 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 when n is 2 or more Each of R ₄ and R ₅ may represent another group in a plurality of occurrences, and at least one of R ₁ to R ₈ represents a phenyl group.) The composition according to claim 4, wherein at least one of R ₁ to R ₃ is a phenyl group and at least one of R ₆ to R ₈ is a phenyl group. The polyimide precursor according to any one of claims 1 to 5, wherein at least one of the structure represented by the following general formula (I) and the amide structure in the general formula (I) is selected from structures in which imidation has been carried out. A composition comprising repeating units.

(In Formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, R ₁ and R ₂ are independently of each other a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or It is an alkylsilyl group having 3 to 9 carbon atoms.) The content of the repeating unit represented by the general formula (I) according to claim 6, wherein X ₁ is a tetravalent group having an alicyclic structure and Y ₁ is a divalent group having an alicyclic structure, based on all repeating units, 50 mol% A composition characterized by the following. 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 method according to claim 6, wherein X ₁ of Formula (I) contains a repeating unit of a tetravalent group having an alicyclic structure in a proportion of more than 60% of all repeating units (provided that X ₁ is a tetravalent group having an alicyclic structure). group and the content of the repeating unit represented by the general formula (I), wherein Y ₁ is a divalent group having an alicyclic structure, is 50 mol% or less with respect to all repeating units). The method according to claim 6, wherein Y ₁ of general formula (I) is of the following formula (4):

{In Formula (4), n ₁₁ to n ₁₃ each independently represents an integer of 0 to 4, and R ₅₁ , R ₅₂ , and R ₅₃ are each independently an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, A carboxyl group or a trifluoromethyl group, W ₁ is a direct bond, -CO-, -NHCO-, -CONH-, -COO-, -OCO-, or Formula (6):

(R ₆₁ to R ₆₈ are a direct bond, -CO-, -NHCO-, -CONH-, -COO- or -OCO-.)}
A composition characterized by containing the group represented by in an amount of 60 mol% or more with respect to the total Y ₁ . 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;
write
A polyimide film/substrate laminate characterized by having a. The laminate according to claim 14, wherein the substrate 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, and
(b) a step of heating the polyimide precursor on the substrate and laminating a polyimide film on the substrate
Method for producing a polyimide film/substrate laminate having a. The manufacturing method according to claim 16, wherein the substrate 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 heating the polyimide precursor on the substrate to produce a polyimide film/substrate laminate in which a polyimide film is laminated on the substrate;
(c) a step of forming at least one layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate, and
(d) step of peeling the substrate and the polyimide film
Method for manufacturing a flexible electronic device having a. The manufacturing method according to claim 18, wherein the substrate is a glass plate.

Images