JP6086139B2 - Polyimide precursor and polyimide - Google Patents

Description

The present invention relates to a polyimide precursor and a polyimide that have excellent heat resistance and also have extremely high transparency.

  In recent years, with the arrival of an advanced information society, development of optical materials such as a liquid crystal alignment film and a protective film for a color filter in the display device field, such as an optical fiber and an optical waveguide in the optical communication field, is progressing. Especially in the field of display devices, we are actively investigating plastic substrates that are lightweight and have excellent flexibility as glass substrate substitutes, and developing displays that can be bent and rolled, and are used for such applications. There is a need for higher performance optical materials that can be used.

  Aromatic polyimide is essentially yellowish brown due to intramolecular conjugation and the formation of charge transfer complexes. For this reason, as a means to suppress coloration, for example, introduction of fluorine atoms into the molecule, imparting flexibility to the main chain, introduction of bulky groups as side chains, etc. inhibits intramolecular conjugation and charge transfer complex formation. Thus, a method for expressing transparency has been proposed. In addition, a method for expressing transparency by using a semi-alicyclic or fully alicyclic polyimide that does not form a charge transfer complex in principle has been proposed.

Patent Document 1 has high transparency, high film toughness, high glass transition temperature, and solution processability used for liquid crystal display substrates, organic electroluminescence display substrates, electronic paper substrates, solar cell substrates, and the like. In order to obtain a plastic substrate, it is disclosed to use a polyimide having an ester bond-containing tetracarboxylic acid precursor.
Patent Document 2 discloses a polyamic acid and / or polyimide using an amide bond-containing compound as a liquid crystal aligning agent. The polyamic acid and / or polyimide has an amide bond in the diamine component used, and the acid dianhydride component has aliphatic, alicyclic or aromatic.

  However, in the polyimides of Patent Document 1 and Patent Document 2, there are cases where both the requirements of high heat resistance and transmittance are not satisfied, and there is a demand for satisfying all of these requirements.

JP 2008-297362 A JP-A-5-203952

  The present invention has been made in view of the above circumstances, and is a semi-finished product using an alicyclic tetracarboxylic dianhydride as a tetracarboxylic acid component and an aromatic diamine having an amide bond and an alicyclic ring as a diamine component. The purpose of the alicyclic polyimide is to improve heat resistance and transmittance.

  That is, an object of the present invention is to provide a polyimide precursor and a polyimide that have excellent characteristics such as high heat resistance and also have extremely high transparency.

The present invention relates to the following items.
1. The polyimide precursor characterized by including the repeating unit represented by following Chemical formula (1).

Here, A is a divalent group having two or more amide bonds and one or more alicyclic rings in the chemical structure, and B has at least one aliphatic six-membered ring in the chemical structure. It is a tetravalent group having no aromatic ring. X ₁ and X ₂ are each independently hydrogen, an alkyl group having 1 to 3 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.

2. 2. The polyimide precursor according to item 1, wherein A is a divalent group selected from the group consisting of the following chemical formulas (2) to (5).

Here, R ₁ and R ₃ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, and R ₂ is a divalent group having an alicyclic ring having 3 to 18 carbon atoms. , And n1 is an integer of 1-10.

Here, R ₄ and R ₆ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, and R ₅ is a divalent group having an alicyclic ring having 3 to 18 carbon atoms. , And n2 is an integer of 1-10.

Here, R ₇ and R ₉ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, and R ₈ is a divalent group having an alicyclic ring having 3 to 18 carbon atoms. , And n3 is an integer of 1-10.

Here, R ₁₀ and R ₁₂ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, and R ₁₁ is a divalent group having an alicyclic ring having 3 to 18 carbon atoms. , And n4 is an integer of 1-10.

3. 2. The polyimide precursor according to item 1, wherein B is a tetravalent group selected from the group consisting of the following chemical formulas (6) to (9).

Here, R ₁₃ is a direct bond, CH ₂ group, C (CH ₃ ) ₂ group, SO ₂ group, Si (CH ₃ ) ₂ group, C (CF ₃ ) ₂ group, oxygen atom, or sulfur atom. is there.

Here, R ₁₄ is any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.

Here, R ₁₅ and R ₁₆ are each independently any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.

4). 4. The polyimide precursor solution composition, wherein the polyimide precursor according to any one of items 1 to 3 is uniformly dissolved in an organic solvent.

5. The polyimide characterized by including the repeating unit represented by following Chemical formula (10).

Here, A is a divalent group having two or more amide bonds and one or more alicyclic rings in the chemical structure, and B has at least one aliphatic six-membered ring in the chemical structure. It is a tetravalent group having no aromatic ring.

6). Item 6. The polyimide according to Item 5, wherein A is a divalent group selected from the group consisting of the following chemical formulas (11) to (14).

Here, R ₁₇ and R ₁₉ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, and R ₁₈ is a divalent group having an alicyclic ring having 3 to ₁₈ carbon atoms. , And n5 is an integer of 1-10.

Here, R ₂₀ and R ₂₂ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, and R ₂₁ is a divalent group having an alicyclic ring having 3 to 18 carbon atoms. , And n6 is an integer of 1-10.

Here, R ₂₃ and R ₂₅ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, and R ₂₄ is a divalent group having an alicyclic ring having 3 to 18 carbon atoms. , And n7 is an integer of 1-10.

Here, R ₂₆ and R ₂₈ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, and R ₂₇ is a divalent group having an alicyclic ring having 3 to 18 carbon atoms. , And n8 is an integer of 1-10.

7). Item 6. The polyimide according to Item 5, wherein B is a tetravalent group selected from the group consisting of the following chemical formulas (15) to (18).

Here, R ₂₉ is a direct bond, CH ₂ group, C (CH ₃ ) ₂ group, SO ₂ group, Si (CH ₃ ) ₂ group, C (CF ₃ ) ₂ group, oxygen atom, or sulfur atom. is there.

Here, R ₃₀ is any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.

Here, R ₃₁ and R ₃₂ are each independently any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.

8). Item 8. A polyimide film formed using the polyimide obtained by using the polyimide precursor solution composition according to item 4 or the polyimide according to item 5-7.

  A diamine having the structure represented by the following chemical formula (19).

Here, R ₃₃ is a divalent group having an alicyclic ring having 3 to 18 carbon atoms. An alicyclic ring is any of a monocyclic ring, a polycyclic ring, a spiro ring, and a bridged ring.

An object of the present invention is to provide a polyimide precursor and a polyimide that have excellent characteristics of high heat resistance and also have extremely high transparency.

The polyimide precursor of this invention is a polyimide precursor comprised including the repeating unit represented by the said Chemical formula (1).
In other words, the polyimide precursor of the present invention includes at least one alicyclic tetracarboxylic acid component having at least one aliphatic 6-membered ring in the chemical structure and no aromatic ring, and two or more in the chemical structure. It is a semi-alicyclic polyimide precursor obtained from an aromatic diamine component having an amide bond and one or more alicyclic rings.

In the present invention, the diamine component is an aromatic diamine component having two or more amide bonds and one or more alicyclic rings in the chemical structure.
In the polyimide precursor of the present invention, an amide bond is introduced into the chemical structure by the diamine component. The polyimide obtained from the polyimide precursor having an amide bond introduced is considered to have improved solvent resistance and the like because the intermolecular interaction is increased by the amide bond. Therefore, the diamine component preferably has two or more amide bonds in the chemical structure. In addition, when there are too many amide bonds in a diamine component, the solubility of a polyimide precursor may fall. Further, by having an alicyclic structure, conjugation and charge transfer interaction inside and outside the molecule are hindered, and transparency is increased.

  The diamine component that introduces the chemical structures of the chemical formulas (2) to (5) and (11) to (14) is obtained by reacting, for example, a nitro compound having a specific reactive group and a compound having a specific reactive group. Later it is obtained by reduction of the nitro group.

  n1-8 shows the integer of 1-10, Preferably it is an integer of 1-5. As a synthesis method of the compounds (2), (3), (11), and (12), for example, an alicyclic compound having a diacid chloride group and an amine compound having a nitro group are reacted in a solvent in the presence of basicity. And then reducing the nitro group of the reaction product to an amino group.

  As a synthesis method of the compounds (4), (5), (13), and (14), for example, an alicyclic compound having a diamine and a nitro compound having an acid chloride are reacted in a solvent in the presence of a basic compound. And a method of reducing the nitro group of the reaction product to an amino group.

  For the reduction, palladium-carbon, platinum-carbon, Raney nickel, rhodium-alumina, iron or the like can be used as a catalyst, and reduction can be performed with hydrogen gas, hydrochloric acid, hydrazine or the like.

  As a solvent used for the reduction reaction, for example, a solvent having high solubility in raw materials such as 1,3-dimethyl-2-imidazolidinone, N-methyl-pyrrolidone, N, N-dimethylformamide is preferable, Any type of solvent can be used without any problem as long as it does not react with the raw material or product, so that the structure is not particularly limited.

R ₂ , R ₅ , R ₈ , R ₁₁ , R ₁₈ , R ₂₁ , R ₂₄ , and R _{27 in the} chemical formulas (2) to (5) and (11) to (14) are an alicyclic ring having 3 to 18 carbon atoms. Is a divalent group. An alicyclic ring is any of a monocyclic ring, a polycyclic ring, a spiro ring, and a bridged ring. One example thereof is a divalent group selected from the group consisting of the following chemical formulas (20) to (25). In particular, the following chemical formula (20) is preferable.

Here, n9 is an integer of 1-16. (When n9 is 1, it represents a 3-membered ring, and when n9 is 1, it represents a 4-membered ring.)

Here, n10 and n11 are each independently an integer of 1 to 15.

Here, n12 and n13 are each independently an integer of 1 to 14.

Here, R ₃₄ , R ₃₅ , and R ₃₆ are CH ₃ groups, C (CH ₃ ) ₃ groups, Si (CH ₃ ) ₃ groups, CF ₃ groups, OH groups, OCH ₃ groups, or CH ₂ CH A group connected by a group.

Here, R ₃₇ is any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.

R < ₁ >, R < ₃ >, R < ₄ >, R < ₆ >, R < ₇ >, R < ₉ >, R < ₁₀ >, R < ₁₂ >, R <_17> , R <_19> , R < ₂₀ > in the chemical formulas (2) to (5) and (11) to (14). , R ₂₂ , R ₂₃ , R ₂₅ , R ₂₆ , R ₂₈ are any of divalent groups selected from the group consisting of the following chemical formulas (26) to (29).

Here, R ₃₈ is any one of a CH ₃ group, a C (CH ₃ ) ₃ group, a Si (CH ₃ ) ₃ group, a CF ₃ group, an OH group, and an OCH ₃ group.

Here, R ₃₉ is a direct bond, a CH ₂ group, a C (CH ₃ ) ₂ group, a SO ₂ group, a Si (CH ₃ ) ₂ group, a C (CF ₃ ) ₂ group, an oxygen atom, or a sulfur atom. is there.

  Examples of the alicyclic compound having diacid chloride include 1,2-cyclopropanedicarboxylic acid dichloride, 1,2-cyclobutanedicarboxylic acid dichloride, 1,3-cyclobutanedicarboxylic acid dichloride, and 1,2-cyclopentanedicarboxylic acid dichloride. 1,3-cyclopentanedicarboxylic acid dichloride, 1,2-cyclohexanedicarboxylic acid dichloride, 1,3-cyclohexanedicarboxylic acid dichloride, 1,4-cyclohexanedicarboxylic acid dichloride, 1,4- (2-norbornene) dicarboxylic acid dichloride 1,4-bicyclo [2.2.2] octane dicarboxylic acid dichloride, 4,4′-spirobicyclohexane dicarboxylic acid dichloride, 1,3-adamantane dicarboxylic acid dichloride, etc. Bonn acid dichloride and the like. Of these, 1,4-cyclohexanedicarboxylic acid dichloride and 1,3-adamantanedicarboxylic acid dichloride are preferred.

  Examples of amino compounds having a nitro group include o-nitroaniline, m-nitroaniline, p-nitroaniline, 4-amino-4'-nitrobiphenyl, 3-amino-4'-nitrobiphenyl, 4-amino-3 '. -Nitrobiphenyl, 1-amino-4-nitronaphthalene, 1-amino-5-nitronaphthalene and the like. Of these, p-nitroaniline and 4-amino-4'-nitrobiphenyl are preferred.

  Examples of the alicyclic compound having a diamine include 1,2-diaminocyclopropane, 1,2-diaminocyclobutane, 1,3-diaminocyclobutane, 1,2-diaminocyclopentane, 1,3-diaminocyclopentane, 1 , 2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,4-diamino (2-norbornene), 1,4-diaminobicyclo [2.2.2] octane, 4,4 ′ -Cycloaliphatic diamines such as diaminospirobicyclohexane and 1,3-diaminoadamantane. Of these, 1,4-diaminocyclohexane and 1,3-diaminoadamantane are preferred.

  Nitro compounds having acid chloride include 2-nitrobenzoyl chloride, 3-nitrobenzoyl chloride, 4-nitrobenzoyl chloride, 4′-nitro-1,1′-biphenyl-4-carboxylic acid chloride, 3′-nitro- 1,1′-biphenyl-4-carboxylic acid chloride, 4′-nitro-1,1′-biphenyl-3-carboxylic acid chloride, 4-nitro-1-naphthalenecarboxylic acid chloride, 5-nitro-1-naphthalenecarboxylic acid And acid chloride. Of these, 4-nitrobenzoyl chloride and 4'-nitro-1,1'-biphenyl-4-carboxylic acid chloride are preferred.

The diamine component of the present invention is based on a combination of the alicycles of the chemical formulas (20) to (25) and the aromatics of the chemical formulas (26) to (29). For this reason, examples of the diamine component include N, N ′-(1,4-bicyclo [2.2.2] octanediyl) bis (4-aminobenzamide), N, N ′-(1,4-bicyclo). [2.2.1] Heptanediyl) bis (4-aminobenzamide), N, N ′-(1,3-adamantanediyl) bis (4-aminobenzamide), N, N ′-(1,4-cyclohexanediyl) ) Bis (4-aminobenzamide), N, N′-bis (4-aminophenyl) -1,4-cyclohexanedicarboxamide, N, N′-bis (4-aminophenyl) -1,4-bicyclo [ 2.2.2] Octanedicarboxamide, N, N′-bis (4-aminophenyl) -1,4-bicyclo [2.2.1] heptanedicarboxamide, N, N′-bis (4- Aminophenyl) -1 Such as 3-adamantane dicarboxamide amides. Of these, N, N ′-(1,3-adamantanediyl) bis (4-aminobenzamide) and N, N ′-(1,4-cyclohexanediyl) bis (4-aminobenzamide) are preferable.

  A plurality of the diamine components of the present invention can be used in combination, and other diamine components generally used in polyimide are in a small amount (preferably less than 30 mol%, within a range where the characteristics of the polyimide of the present invention can be expressed). More preferably, it can be used in combination.

In the present invention, the tetracarboxylic acid component is an alicyclic tetracarboxylic acid component having at least one aliphatic 6-membered ring and no aromatic ring in the chemical structure, and therefore there are a plurality of 6-membered rings. A plurality of 6-membered rings may be composed of two or more common carbon atoms. Further, the 6-membered ring may be a bridged ring type in which carbon atoms constituting the ring (inside the 6-membered ring) further form a ring by a chemical bond.
A tetracarboxylic acid component having a six-membered ring structure that is not asymmetrical and highly symmetric is preferable because it enables high-density packing of polymer chains and is excellent in solvent resistance, heat resistance, and mechanical strength of polyimide. . Furthermore, the tetracarboxylic acid component is a polyalicyclic type in which a plurality of 6-membered rings are constituted by two or more common carbon atoms, and the carbon atoms in which the 6-membered rings form a ring further form a ring by a chemical bond. The formed crosslinked ring type is more preferable because good heat resistance, solvent resistance, and low linear expansion property of polyimide can be easily achieved.

Examples of the tetracarboxylic acid component into which the chemical structures of the chemical formulas (6), (7), (15), and (16) are introduced include cyclohexane-1,2,4,5-tetracarboxylic acid, [1,1 ′ -Bi (cyclohexane)]-3,3 ', 4,4'-tetracarboxylic acid, [1,1'-bi (cyclohexane)]-2,3,3', 4'-tetracarboxylic acid, [1, 1′-bi (cyclohexane)]-2,2 ′, 3,3′-tetracarboxylic acid, 4,4′-methylenebis (cyclohexane-1,2-dicarboxylic acid), 4,4 ′-(propane-2, 2-diyl) bis (cyclohexane-1,2-dicarboxylic acid), 4,4′-oxybis (cyclohexane-1,2-dicarboxylic acid), 4,4′-thiobis (cyclohexane-1,2-dicarboxylic acid), 4,4′-sulfonylbis (cyclohexane-1,2- Carboxylic acid), 4,4 ′-(dimethylsilanediyl) bis (cyclohexane-1,2-dicarboxylic acid), 4,4 ′-(tetrafluoropropane-2,2-diyl) bis (cyclohexane-1,2- And derivatives thereof such as dicarboxylic acids) and acid dianhydrides thereof. Among these, 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 derivatives and these The acid dianhydride is preferred.
Although these tetracarboxylic acid components are not particularly limited, the ratio of specific stereoisomers is 80% or more, more preferably 90% or more, and particularly preferably 95% or more by performing separation and purification. Excellent heat resistance and solvent resistance. The specific stereoisomer of the tetracarboxylic acid component is 1R, 2S, 4S, 5R-cyclohexanetetracarboxylic acid (hereinafter abbreviated as PMTA-HS, and the acid dianhydride is further referred to as PMDA-HS. 1S, 2S, 4R, 5R-cyclohexanetetracarboxylic acid (hereinafter may be abbreviated as PMTA-HH, and the acid dianhydride may be abbreviated as PMDA-HH), (1R , 1 ′S, 3R, 3 ′S, 4R, 4 ′S) dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic acid (hereinafter sometimes abbreviated as trans-DCTA). trans-DCDA may be abbreviated.), (1R, 1 ′S, 3R, 3 ′S, 4S, 4′R) dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic acid (hereinafter cis-DCTA) And abbreviation In some cases, the acid dianhydride may be abbreviated as cis-DCDA.) PMTA-HS, trans-DCTA, and cis-DCTA are excellent in reactivity when acid dianhydride is used. More preferable.

Examples of the polyalicyclic or cross-linked tetracarboxylic acid component that introduces the chemical structures of the chemical formulas (8), (9), (17), and (18) include, for example, 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, decahydro-1,4: 5,8-dimethanol naphthalene 2,3,6,7 derivatives and their acid dianhydrides such as tetracarboxylic acid. Among these, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, decahydro -1,4: 5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic acid and the like and their acid dianhydrides are easy to produce and the heat resistance of the resulting polyimide It is more preferable because it is excellent.
Although these tetracarboxylic acid components are not particularly limited, the ratio of specific stereoisomers is 80% or more, more preferably 90% or more, and particularly preferably 95% or more by performing separation and purification. Excellent heat resistance and solvent resistance. Moreover, as a specific stereoisomer of the tetracarboxylic acid component,
1rC7-bicyclo [2.2.2] octane-2t, 3t, 5c, 6c-tetracarboxylic acid-2,3: 5,6-dianhydride (hereinafter sometimes abbreviated as cis / trans-BTTA-H, Further, the acid dianhydride may be abbreviated as cis / trans-BTA-H.)
1rC7-bicyclo [2.2.2] octane-2c, 3c, 5c, 6c-tetracarboxylic acid-2,3: 5,6-dianhydride (hereinafter sometimes abbreviated as cis / cis-BTTA-H, Further, the acid dianhydride may be abbreviated as cis / cis-BTA-H.)
(4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acid (hereinafter sometimes abbreviated as DNTAxx, and the acid dianhydride is further abbreviated as DNDAxx. Sometimes.)
(4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene-2c, 3c, 6c, 7c-tetracarboxylic acid (hereinafter sometimes abbreviated as DNTAdx, and the acid dianhydride is further abbreviated as DNDAdx) Sometimes.)
Are preferred, and DNDAxx and DNDAdx are more preferred because of their excellent reactivity with diamines.

  The tetracarboxylic acid component may be a single tetracarboxylic acid component as described above, or may be used in combination of two or more. In addition, other aromatic or aliphatic tetracarboxylic acid components generally used in polyimide are in a small amount (preferably less than 30 mol%, more preferably less than 10 mol%) within the range in which the characteristics of the polyimide of the present invention can be expressed. ) Can be used together. For example, other aromatic or aliphatic tetracarboxylic acid components that can be used in the present invention include 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 4- (2,5-dioxy). Oxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid, pyromellitic acid, benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, oxydiphthalic acid, biscarboxyphenyldimethylsilane, bis Examples include dicarboxyphenoxydiphenyl sulfide, sulfonyldiphthalic acid, cyclobutanetetracarboxylic acid, isopropylidenediphenoxybisphthalic acid, and acid dianhydrides thereof.

In the polyimide precursor of the present invention, X ₁ and X _{2 in} the chemical formula (1) are each independently hydrogen, an alkyl group having 1 to 3 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms. X ₁ and X ₂ can change the type of the functional group and the introduction rate of the functional group by a production method described later. X ₁ and X ₂ are preferably hydrogen because the production method is easy. Further, because of excellent storage stability of the polyimide precursor, X _1, X ₂ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group or an ethyl group. Furthermore, since the linear thermal expansion coefficient of polyimide becomes small, X ₁ and X ₂ are preferably an alkylsilyl group having 3 to 9 carbon atoms, and more preferably a trimethylsilyl group or a t-butyldimethylsilyl group. The introduction rate of the functional group is not particularly limited, but when an alkyl group or an alkylsilyl group is introduced, X ₁ and X ₂ are each 25% or more, preferably 50% or more, more preferably 75% or more.

The polyimide precursor of the present invention can be classified as a chemical structure into 1) polyamic acid, 2) polyamic acid ester, and 3) polyamic acid silyl ester according to the chemical structure taken by X ₁ and X ₂ . And it can manufacture easily with the following manufacturing methods for every said classification. However, the manufacturing method of the polyimide precursor of this invention is not necessarily limited to the following manufacturing methods.

1) Polyamic acid A diamine is dissolved in an organic solvent, and tetracarboxylic dianhydride is gradually added to this solution while stirring, followed by stirring at 0 to 120 ° C, preferably 5 to 80 ° C for 1 to 72 hours. Thereby, a polyimide precursor is obtained. When the reaction is carried out at 80 ° C. or higher, the molecular weight varies depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be produced stably.
Moreover, when the molar ratio of the tetracarboxylic acid component and the diamine component is an excess of the diamine component, if necessary, an amount of a carboxylic acid derivative substantially corresponding to the excess mole number of the diamine component is added, and the tetracarboxylic acid component and the diamine are added. The molar ratio of the components can be approximated to the equivalent. As the carboxylic acid derivative herein, a tetracarboxylic acid that does not substantially increase the viscosity of the polyimide precursor solution, that is, substantially does not participate in molecular chain extension, or a tricarboxylic acid that functions as a terminal terminator and its anhydride, Dicarboxylic acid and its anhydride are preferred.

2) Polyamic acid ester After reacting tetracarboxylic dianhydride with an arbitrary alcohol to obtain a diester dicarboxylic acid, it is reacted with a chlorinating reagent (thionyl chloride, oxalyl chloride, etc.) to obtain a diester dicarboxylic acid chloride. A polyimide precursor is obtained by stirring the diester dicarboxylic acid chloride and the diamine at -20 to 120 ° C, preferably -5 to 80 ° C for 1 to 72 hours. When the reaction is carried out at 80 ° C. or higher, the molecular weight varies depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be produced stably. Alternatively, a polyimide precursor can be easily obtained by dehydrating and condensing diester dicarboxylic acid and diamine using a phosphorus condensing agent or a carbodiimide condensing agent. Since the polyimide precursor obtained by this method is stable, it can also be purified by reprecipitation by adding a solvent such as water or alcohol.

3) Polyamic acid silyl ester A diamine and a silylating agent are reacted in advance to obtain a silylated diamine (if necessary, purification of the silylated diamine by distillation or the like), and in a dehydrated solvent In the solution, the silylated diamine is dissolved, and while stirring, tetracarboxylic dianhydride is gradually added, and the mixture is stirred at 0 to 120 ° C., preferably 5 to 80 ° C. for 1 to 72 hours, A polyimide precursor is obtained. When the reaction is carried out at 80 ° C. or higher, the molecular weight varies depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be produced stably. As the silylating agent used here, it is preferable to use a silylating agent not containing chlorine because it is not necessary to purify the silylated diamine. Examples of the silylating agent not containing a chlorine atom include N, O-bis (trimethylsilyl) trifluoroacetamide, N, O-bis (trimethylsilyl) acetamide, and hexamethyldisilazane. N, O-bis (trimethylsilyl) acetamide and hexamethyldisilazane are preferred because they do not contain fluorine atoms and are low in cost. In addition, amine-based catalysts such as pyridine, piperidine and triethylamine can be used in the silylation reaction of diamine in order to accelerate the reaction. This catalyst can be used as it is as a polymerization catalyst for the polyimide precursor.

  Moreover, since all the said manufacturing methods can be performed suitably in an organic solvent, as a result, the polyimide precursor solution composition of this invention can be obtained easily.

  The solvent used in preparing the polyimide precursor is preferably an aprotic solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, etc. If the monomer component and the polyimide precursor to be produced are dissolved, any type of solvent can be used without any problem, and the structure is not particularly limited. Amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ -Cyclic ester solvents such as butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, phenol solvents such as m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol, Acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably employed. In addition, other common organic solvents such as phenol, 0-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, ptyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, Tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, Petroleum naphtha solvents can also be used.

  The solvent used in preparing the polyimide precursor and the solvent used in the polyimide precursor solution composition described below (hereinafter, sometimes referred to as an organic solvent used in combination) are related to the following purity. Characteristics, ie, (a) light transmittance, (b) light transmittance after heat reflux treatment, (c) purity by gas chromatography analysis, (d) impurity peak ratio by gas chromatography analysis, (e) non-volatile It is preferable to satisfy the conditions defined below with respect to at least one of the component amount and (f) the metal component content, and it is usually more preferable to satisfy more conditions.

(A) As an organic solvent to be used, an organic solvent having a light transmittance of 89% or more, more preferably 90% or more, particularly preferably 91% or more at an optical path length of 1 cm and 400 nm. (B) As an organic solvent to be used An organic solvent having an optical path length of 1 cm after refluxing in nitrogen for 3 hours and a light transmittance at 400 nm of 20% or more, more preferably 40% or more, and particularly preferably 80% or more. (C) Organic solvent used An organic solvent having a purity determined by gas chromatography analysis of 99.8% or more, more preferably 99.9% or more, and even more preferably 99.99% or more (d) The total amount of impurity peaks appearing on the long side with respect to the retention time of the main component peak obtained by chromatography analysis is less than 0.2%, more preferably Organic solvent that is 0.1% or less, and particularly preferably 0.05% or less (e) The non-volatile component at 250 ° C. of the organic solvent used is 0.1% or less, more preferably 0.05% or less (F) Metal component of the organic solvent used (for example, Li, Na, Mg, Ca, Al, K, Ca, Ti, Cr, Mn, Fe) , Co, Ni, Cu, Zn, Mo, Cd) is preferably 10 ppm or less, more preferably 1 ppm or less, particularly 500 ppb or less, and particularly preferably 300 ppb or less.

  Moreover, the conditions in these characteristics are based on the sum total of the organic solvent used. That is, the organic solvent used is not limited to one type and may be two or more types. Two or more types of organic solvents are used when a mixed solvent is used in a specific process or when a different solvent is used depending on the process, for example, when a polymerization solvent and a diluent solvent for an additive are different. Also means. When two or more types of organic solvents are used (hereinafter referred to as mixed solvents), the conditions of each characteristic relating to purity are applied to the entire mixed solvent, and when organic solvents are used in multiple steps The condition of each characteristic relating to purity is applied to a mixed solvent in which all organic solvents to be finally contained in the varnish are mixed. Each characteristic may be measured by actually mixing an organic solvent, or the characteristics of each organic solvent may be obtained, and the characteristics of the entire mixture may be obtained by calculation. For example, when 70 parts of solvent A having a purity of 100% and 30 parts of solvent B having a purity of 90% are used, the purity of the organic solvent used is calculated to be 97%.

  The solvent used in the polyimide precursor solution composition of the present invention is not a problem as long as the polyimide precursor is dissolved, and the structure is not particularly limited. Amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ -Cyclic ester solvents such as butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, phenol solvents such as m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol, Acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably employed. In addition, other common organic solvents such as phenol, 0-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, ptyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, Tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, Petroleum naphtha solvents can also be used. A combination of these can be used.

  The polyimide precursor solution composition of the present invention may contain chemical imidizing agents (acid anhydrides such as acetic anhydride, amine compounds such as pyridine and isoquinoline), antioxidants, fillers, dyes, pigments, silanes as necessary. Coupling agents such as coupling agents, primers, flame retardants, antifoaming agents, leveling agents, rheology control agents (flow aids), release agents and the like can be added.

  The polyimide of the present invention is characterized by including a repeating unit represented by the chemical formula (10), and is suitably obtained by subjecting the polyimide precursor of the present invention to a dehydration ring-closing reaction (imidation reaction). Can be manufactured. The imidization method is not particularly limited, and known thermal imidization and chemical imidization methods can be suitably applied. As for the form of the polyimide to be obtained, a film, a laminate of the polyimide film and another substrate, a coating film, powder, beads, a molded body, a foam, a varnish, and the like can be preferably exemplified.

  When the polyimide of the present invention is a film having a thickness of 10 μm, the light transmittance at 400 nm is 65% or more, preferably 70% or more, more preferably 75% or more, and particularly preferably 80% or more. It has high transparency.

  Further, the polyimide of the present invention has a 5% weight loss temperature of 420 ° C. or higher, preferably 450 ° C. or higher, more preferably 477 ° C. or higher when formed into a film, and has excellent heat resistance.

  In addition, although the film which consists of a polyimide of this invention is based also on a use, Preferably it is about 1 micrometer-250 micrometers as a film thickness, More preferably, it is about 1 micrometer-150 micrometers.

  The polyimide of the present invention has excellent properties such as high heat resistance, and also has extremely high transparency. Therefore, the polyimide of the present invention is suitably used in applications for transparent substrates for displays, transparent substrates for touch panels, or substrates for solar cells. be able to.

Below, an example of the manufacturing method of a polyimide film / base material laminated body or a polyimide film using the polyimide precursor of this invention is described. However, it is not limited to the following method.
For example, the polyimide precursor solution composition of the present invention is cast on a base material such as ceramic (glass, silicon, alumina), metal (copper, aluminum, stainless steel), heat-resistant plastic film (polyimide), nitrogen, etc. In an inert gas or in the air, using hot air or infrared rays, and drying in a temperature range of 20 to 180 ° C, preferably 20 to 150 ° C. Next, the obtained polyimide precursor film is peeled off from the substrate, or the polyimide precursor film is peeled off from the substrate, and the end of the film is fixed, in vacuum, in an inert gas such as nitrogen, or A polyimide film / substrate laminate or a polyimide film can be produced by hot imidization in air using hot air or infrared rays at a temperature of about 200 to 500 ° C., more preferably about 250 to 450 ° C. In order to prevent the resulting polyimide film from being oxidized and deteriorated, it is desirable to carry out the heating imidization in a vacuum or in an inert gas. If the temperature of the heating imidization is not too high, it may be performed in air. The thickness of the polyimide film here (in the case of a polyimide film / substrate laminate) is preferably 1 to 250 μm, more preferably 1 to 150 μm, for transportability in the subsequent steps.

  Further, the imidation reaction of the polyimide precursor contains a dehydration cyclization reagent such as acetic anhydride in the presence of a tertiary amine such as pyridine or triethylamine instead of the heating imidation by the heat treatment as described above. It is also possible to carry out by chemical treatment such as immersion in a solution. Also, a partially imidized polyimide precursor is prepared by previously charging and stirring these dehydrating cyclization reagents in a polyimide precursor solution composition, and casting and drying them on a substrate. In addition, a polyimide film / substrate laminate or a polyimide film can be obtained by further heat-treating this as described above.

  The polyimide film / base laminate or the polyimide film thus obtained can be used to form a flexible conductive substrate by forming a conductive layer on one side or both sides thereof.

A flexible conductive substrate can be obtained, for example, by the following method. That is, as a first method, a conductive material (metal or metal oxide) is formed on the polyimide film surface by sputtering deposition, printing or the like without peeling the polyimide film / substrate laminate from the substrate. , Conductive organic material, conductive carbon, etc.) are formed to produce a conductive layer / polyimide film / substrate laminate. Thereafter, if necessary, a transparent and flexible conductive substrate composed of the conductive layer / polyimide film laminate can be obtained by peeling the electric conductive layer / polyimide film laminate from the base material.
As a second method, the polyimide film is peeled off from the substrate of the polyimide film / substrate laminate to obtain a polyimide film, and a conductive substance (metal or metal oxide, conductive organic substance, A conductive layer of conductive carbon or the like can be formed in the same manner as in the first method, and a transparent and flexible conductive substrate comprising a conductive layer / polyimide film laminate can be obtained.
In the first and second methods, if necessary, before forming a conductive layer on the surface of the polyimide film, a gas barrier layer such as water vapor or oxygen, a light adjusting layer, etc. by sputtering deposition or gel-sol method. An inorganic layer such as may be formed.
The conductive layer is preferably formed with a circuit by a photolithography method, various printing methods, an inkjet method, or the like.

The board | substrate of this invention has a circuit of a conductive layer on the surface of the polyimide film comprised by the polyimide of this invention through a gas barrier layer and an inorganic layer as needed. This substrate is flexible, excellent in transparency, bendability, and heat resistance, and has an extremely low coefficient of thermal expansion and solvent resistance, so that a fine circuit can be easily formed. Therefore, this board | substrate can be used suitably as a board | substrate for displays, a touch panel, or a solar cell.
That is, a transistor (inorganic transistor, organic transistor) is further formed on this substrate by vapor deposition, various printing methods, an ink jet method or the like to manufacture a flexible thin film transistor, and a liquid crystal element, an EL element, a photoelectric transistor for a display device are manufactured. It is suitably used as an element.

  Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples. In addition, this invention is not limited to a following example.

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

Evaluation of polyimide film
[Light transmittance]
The light transmittance at 400 nm of a 10 μm-thick polyimide film was measured using MCPD-300 manufactured by Otsuka Electronics.
[5% weight loss temperature]
A polyimide film having a thickness of 10 μm was used as a test piece, and the temperature was increased from 25 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min in a nitrogen stream using a calorimeter measuring device (Q-5000) manufactured by SII Nanotechnology. . From the obtained weight curve, a 5% weight loss temperature was determined.

The abbreviations and purity of the raw materials used in the following examples are as follows.
NAABA: N, N ′-(1,3-adamantanediyl) bis (4-aminobenzamide) purity 99.3% (LC analysis)
NCHABA: N, N ′-(1,4-cyclohexanediyl) bis (4-aminobenzamide) purity 99.2% (LC analysis)
4-APTP: N, N′-bis (4-aminophenyl) terephthalamide Purity 99.95% (GC analysis)
PMDA-HS: 1R, 2S, 4S, 5R-cyclohexanetetracarboxylic dianhydride purity 92.7% (GC analysis), purity 99.9% as hydrogenated pyromellitic dianhydride (GC analysis)
BTA-H: Bicyclo [2.2.2] octane-2,3: 5,6-tetracarboxylic dianhydride purity 99.9% (GC analysis)
DNDAxx: (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethananaphthalene-2t, 3t, 6c, 7c-tetracarboxylic dianhydride purity 99.2% (NMR analysis)

[Synthesis Example 1]
After dissolving 16.1 g of p-nitrobenzoic acid chloride and 10.3 g of pyridine in 80 g of dimethylformamide, 7.2 g of 1,3-diaminoadamantane and 20 g of N, N-dimethylformamide are gradually added dropwise at 25 ° C. The reaction was allowed for 5 hours. Subsequently, the reaction solution was washed three times with a sodium hydrogen carbonate solution, and then the solvent was removed. Thereafter, recrystallization was performed from chloroform and N, N-dimethylformamide to obtain dinitro compounds as pale yellow crystals.

[Synthesis Example 2]
After dissolving 4 g of the dinitro compound obtained in Synthesis Example 1 and 400 mg of 10% Pd / C in 25 g of 1,3-dimethyl-2-imidazolidinone, hydrogen was blown in and a pressure of 3 MPa was applied. Next, the reaction was performed at 70 ° C. for 7 hours, and after cooling to room temperature, depressurization was performed. Thereafter, 10% Pd / C was removed by Celite filtration, and then ultrapure water or a poor solvent was added to obtain NAABA. (Yield 82%, purity 99.3%)

[Synthesis Example 3]
A dinitro compound was obtained in the same manner as in Synthesis Example 1 except that 1,4-diaminocyclohexane was used in place of 1,3-diaminoadamantane in Synthesis Example 1, and a reduction reaction similar to Synthesis Example 2 was performed. Got.

  Table 1 shows the structural formulas of the tetracarboxylic acid component and the diamine component used in Examples and Comparative Examples.

[Example 1]
In a reaction vessel substituted with nitrogen gas, 0.60 g (1.5 mmol) of NAABA was put, and N, N-dimethylacetamide dehydrated using molecular sieve was charged, and the total mass of monomers (total of diamine component and carboxylic acid component) Was added in an amount of 20% by mass and stirred at 25 ° C. for 2 hours.
To this solution, 0.37 g (1.5 mmol) of BTA-H was gradually added. The mixture was stirred at 80 ° C. for 6 hours to obtain a uniform and viscous polyimide precursor solution.

A polyimide precursor solution filtered through a PTFE membrane filter was applied to a glass substrate, and the nitrogen atmosphere (oxygen concentration of 200 ppm or less) was maintained as it was on a glass substrate at 120 ° C. for 1 hour, 150 ° C. for 30 minutes, 200 ° C. for 30 minutes, The temperature was raised to 350 ° C. and heated for 5 minutes to thermally imidize to obtain a colorless and transparent polyimide film / glass laminate. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled to obtain a polyimide film having a thickness of 10 μm.
The results of measuring the properties of this polyimide film are shown in Table 2.

[Examples 2 to 4, Comparative Examples 1 and 2]
The diamine component and the carboxylic acid component were set to the chemical compositions described in Table 2, and a polyimide precursor solution and a polyimide film were obtained in the same manner as in Example 1.
The results of measuring the properties of this polyimide film are shown in Table 2.

From the results shown in Table 2, the polyimide obtained from the polyimide precursor using the diamine having an amide bond and an alicyclic ring of the present invention has a higher transmission than the polyimide obtained from the polyimide precursor using the aromatic diamine. It can be seen that the rate is shown. In addition, the aromatic ring is known to have higher heat resistance than the alicyclic ring, but in the polyimide obtained from the polyimide precursor using the diamine having the alicyclic ring of the present invention, the polyimide using the aromatic diamine is used. It turns out that the heat resistance equivalent to the polyimide obtained from the precursor is shown.
Furthermore, from the comparison of the diamine components in Examples 2 and 4, the polyimide obtained from the polyimide precursor using the adamantane skeleton diamine has higher heat resistance than the polyimide obtained from the polyimide precursor using the cyclohexane skeleton diamine. It can be seen that it exhibits high transmittance and high transmittance.
As described above, the polyimide obtained from the polyimide precursor of the present invention has excellent light transmittance and high heat resistance, and the polyimide film of the present invention is colorless and transparent for display applications and the like. And can be suitably used as a transparent substrate capable of forming a fine circuit.

The present invention can provide a polyimide precursor and a polyimide having excellent heat resistance and extremely high transparency. This polyimide precursor and polyimide have high transparency and a low linear expansion coefficient that facilitates the formation of fine circuits, and therefore can be suitably used for forming substrates for display applications and the like.

Claims (6)

The polyimide precursor characterized by including the repeating unit represented by following Chemical formula (1).
Here, A is a divalent group selected from the group consisting of the following chemical formulas ( 4 ) to (5), and B is an aromatic ring having at least one aliphatic 6-membered ring in the chemical structure. Is a tetravalent group that does not have X ₁ and X ₂ are each independently hydrogen, an alkyl group having 1 to 3 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.
Here, R ₇ and R ₉ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, R ₈ is a divalent group of the following chemical formula (20), and n3 is It is an integer of 1-10.
Here, R ₁₀ and R ₁₂ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, R ₁₁ is a divalent group of the following chemical formula (20), and n4 is It is an integer of 1-10.
The polyimide precursor according to claim 1, wherein B is a tetravalent group selected from the group consisting of the following chemical formulas (6) to (9).

Here, R ₁₃ is a direct bond, CH ₂ group, C (CH ₃ ) ₂ group, SO ₂ group, Si (CH ₃ ) ₂ group, C (CF ₃ ) ₂ group, oxygen atom, or sulfur atom. is there.
Here, R ₁₄ is any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.
Here, R ₁₅ and R ₁₆ are each independently any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.   A polyimide precursor solution composition, wherein the polyimide precursor according to claim 1 is uniformly dissolved in an organic solvent. The polyimide characterized by including the repeating unit represented by following Chemical formula (10).
Here, A is a divalent group selected from the group consisting of the following chemical formulas ( 4 ) to (5), and B is an aromatic ring having at least one aliphatic 6-membered ring in the chemical structure. Is a tetravalent group that does not have
Here, R ₇ and R ₉ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, R ₈ is a divalent group of the following chemical formula (20), and n3 is It is an integer of 1-10.
Here, R ₁₀ and R ₁₂ are each independently a divalent group having an aromatic ring having 6 to 18 carbon atoms, R ₁₁ is a divalent group of the following chemical formula (20), and n4 is It is an integer of 1-10.
The polyimide according to claim 4, wherein B is a tetravalent group selected from the group consisting of the following chemical formulas (6) to (9).

Here, R ₁₃ is a direct bond, CH ₂ group, C (CH ₃ ) ₂ group, SO ₂ group, Si (CH ₃ ) ₂ group, C (CF ₃ ) ₂ group, oxygen atom, or sulfur atom. is there.
Here, R ₁₄ is any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.
Here, R ₁₅ and R ₁₆ are each independently any one of a CH ₂ group, a CH ₂ CH ₂ group, an oxygen atom, and a sulfur atom.   The polyimide film formed using the polyimide obtained using the polyimide precursor solution composition of Claim 3, or the polyimide of Claim 4.