Resin compositions, molded articles, and films

Abstract

The present invention aims to provide a resin composition containing polyamide-imide and polycarbonate that is environmentally safe, soluble in organic solvents, and has excellent transparency, as well as molded articles such as films. [Solution] A resin composition comprising polyamide-imide and polycarbonate, wherein the polyamide-imide is a polyamide-imide having imide bonds and amide bonds, and having a structure derived from at least a tetracarboxylic dianhydride component and a diamine component, and the diamine is CF3-O-,-(CF2-O) n -, -O-(CF2-CF2-O) n The above problem can be solved by a resin composition characterized by containing a diamine having one or more structures selected from any of the following (where n is an integer from 1 to 20).

Description

[Technical Field]

[0001] The present invention relates to resin compositions and molded articles such as films. [Background technology]

[0002] Display devices such as liquid crystal displays, organic EL displays, and electronic paper, as well as electronic devices such as solar cells and touch panels, are required to be thinner, lighter, and more flexible. By replacing the glass material used in these devices with a film material, flexibility, thinning, and weight reduction can be achieved. Transparent polyimide film has been developed as a glass substitute material and is used in display substrates and cover films. Patent document 1 proposes the use of polyamide-imide as a material for the cover film of a flexible display.

[0003] As a method for producing highly transparent polyamide-imide films, a method has been proposed that uses a polyamide-imide resin that is soluble in organic solvents and does not require high-temperature imidation after film formation. Such soluble polyamide-imides use fluorine-containing compounds as the diamine and / or tetracarboxylic dianhydride monomers, from the viewpoint of balancing transparency and mechanical properties. For example, the polyamide-imide in Patent Document 1 uses 2,2'-bis(trifluoromethyl)benzidine (TFMB) as the diamine and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) as the tetracarboxylic dianhydride.

[0004] Patent document 2 describes that the transparency of a film can be improved by mixing soluble polyamide-imide with polycarbonate. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2013 / 048126 [Patent Document 2] Japanese Patent Publication No. 2023-159875 [Overview of the project] [Problems that the invention aims to solve]

[0006] In recent years, the environmental persistence of organofluorine compounds (PFAS) has become a concern. Generally, the carbon-fluorine bonds in organofluorine compounds have high bond energy and are difficult to decompose in the environment. In particular, organofluorine compounds containing structures in which a trifluoromethyl group is bonded to a carbon atom (-C-CF3) or structures in which carbon atoms are bonded to both ends of a difluoromethylene group (-C-CF2-C-) have low decomposability in the environment, and their effects on human health have also been pointed out.

[0007] In view of these issues, the present invention aims to provide a resin composition containing polyamide-imide that is environmentally safe, soluble in organic solvents, and transparent, as well as molded articles such as films. [Means for solving the problem]

[0008] As a result of diligent research, the inventors have found that the above problem can be solved by the following configuration.

[0009] 1) A resin composition comprising polyamide-imide and polycarbonate, The polyamide-imide is a polyamide-imide having imide bonds and amide bonds, and having a structure derived from at least a tetracarboxylic dianhydride component and a diamine component. The aforementioned diamine is CF3-O-, -(CF2-O) n -, -O-(CF2-CF2-O) n A resin composition characterized by containing a diamine having one or more structures selected from the following (where n is an integer from 1 to 20).

[0010] 2) The resin composition according to 1), characterized in that the tetracarboxylic dianhydride component includes one or more acid dianhydrides selected from tetracarboxylic dianhydrides having an ether bond, tetracarboxylic dianhydrides having a fluorene structure, tetracarboxylic dianhydrides having a xanthene structure, and bis(trimellitic anhydride) esters.

[0011] 3) One or more acidic dianhydrides selected from the ether-linked tetracarboxylic dianhydrides, fluorene-containing tetracarboxylic dianhydrides, xanthene-containing tetracarboxylic dianhydrides, and bis(trimellitic anhydride) esters, such as 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride, 3,4'-oxydiphthalic anhydride, 4,4'-oxydiphthalic anhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, and 5,5'-(9H-fluorene-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobene The resin composition according to 2), comprising at least one of the following: zofuran carboxylate, spiro[fluorene-9,9'xanthene]-2',3',6',7'-tetracarboxylic dianhydride, 5,5'-spiro[9H-fluorene-9,9'-[9H]xanthene]-3',6'-diylbis(1,3-dihydro-1,3-dioxo-5-isobenzofuran carboxylate, p-phenylenebis(trimellitic acid monoester anhydride), bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-biphenyl-4,4'diyl, and bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-2,2',3,3',5,5'-hexamethylbiphenyl-4,4'diyl.

[0012] 4) The aforementioned CF3-O-, -(CF2-O) n -, -O-(CF2-CF2-O) nThe diamine having a structure selected from (where n is an integer from 1 to 20) is selected from 2,2'-bis(trifluoromethoxy)benzidine, 3,3'-bis(trifluoromethoxy)benzidine, 2,3'-bis(trifluoromethoxy)benzidine, and the resin composition according to any one of 1) to 3).

[0013] 5). The content of the tetracarboxylic dianhydride component having a CF3-group directly bonded to the aromatic ring of the polyamideimide or -C(CF3)2- directly bonded to the aromatic ring is less than 0.5 mol% in all the tetracarboxylic dianhydride components. The resin composition according to any one of 1) to 4), characterized in that the content of the diamine component having a CF3-group directly bonded to the aromatic ring of the polyamideimide resin composition or -C(CF3)2- directly bonded to the aromatic ring is less than 0.5 mol% in all the diamine components.

[0014] 6). The polyamideimide contains, as the tetracarboxylic dianhydride, one or more acid dianhydrides selected from the tetracarboxylic dianhydride having a fluorene structure, the tetracarboxylic dianhydride having a xanthene structure, the tetracarboxylic dianhydride having an ether bond, and bis(trimellitic anhydride) ester, and the total ratio of the structure derived from the tetracarboxylic dianhydride having a fluorene structure, the structure derived from the tetracarboxylic dianhydride having a xanthene structure, the structure derived from the tetracarboxylic dianhydride having an ether bond, and the structure derived from bis(trimellitic anhydride) ester to the total amount of the structure derived from the tetracarboxylic dianhydride is 50 to 100 mol%. The resin composition according to any one of 1) to 5).

[0015] 7). The resin composition according to any one of 1) to 6), characterized in that the glass transition temperature (Tg) of the polycarbonate is 150 °C or higher.

[0016] 8). The resin composition according to any one of 1) to 7), characterized in that the weight average molecular weight (Mw) of the polycarbonate is 50,000 or higher.

[0017] 9). The resin composition according to any one of 1) to 8), wherein the polyamideimide and the polycarbonate are in a composition ratio (weight ratio) range of 2:98 to 98:2.

[0018] 10). A molded body containing the resin composition according to any one of 1) to 9).

[0019] 11). A film containing the resin composition according to any one of 1) to 9).

Advantages of the Invention

[0020] A resin composition containing a polyamideimide containing a specific diamine as a diamine component and a polycarbonate is excellent in solubility in an organic solvent and transparency. Further, since the specific diamine has lower environmental persistence than an organic fluorine compound such as fluoroalkyl-substituted benzidine, the resin composition and molded bodies such as films of the present invention are excellent in environmental safety.

Modes for Carrying Out the Invention

[0021] The present invention is a resin composition containing a polyamideimide and a polycarbonate, where the polyamideimide has an imide bond and an amide bond and has a structure derived from at least a tetracarboxylic dianhydride component and a diamine component, the diamine contains a diamine having one or more structures selected from any of CF3-O-, -(CF2-O)n-, -O-(CF2-CF2-O) n -(where n is an integer of 1 to 20), and is characterized in that it is a resin composition.

[0022] [Polyamideimide] The polyamideimide of the present invention has an imide bond and an amide bond and has a structure derived from at least a tetracarboxylic dianhydride component and a diamine component.

[0023] Polyamide-imide is a polymer having imide structural units represented by general formula (I) and amide structural units represented by general formula (II) and / or amide-imide structural units represented by general formula (III).

[0024] [ka]

[0025] In general formulas (I) to (III), X is a tetravalent organic group, Y and Z are divalent organic groups, and W is a trivalent organic group. X is a tetracarboxylic dianhydride (hereinafter sometimes referred to as "acid dianhydride") residue, which is an organic group obtained by removing two anhydrous carboxyl groups from a tetracarboxylic dianhydride represented by general formula (IV) below. Y is a diamine residue, which is an organic group obtained by removing two amino groups from a diamine represented by general formula (V) below. Z is a dicarboxylic acid residue, which is an organic group obtained by removing two carboxyl groups from a dicarboxylic acid represented by general formula (VI) below. W is a tricarboxylic acid anhydride residue, which is an organic group obtained by removing two anhydrous carboxyl groups from a tricarboxylic acid anhydride represented by general formula (VII) below.

[0026] [ka]

[0027] In other words, polyamide-imide includes a diamine-derived structure represented by the following general formula (Va) and a tetracarboxylic dianhydride-derived structure represented by the following general formula (IVa), and further includes one or more structures selected from the group consisting of a dicarboxylic acid-derived structure represented by the following general formula (VIa) and a tricarboxylic acid anhydride-derived structure represented by the following general formula (VIIa). The diamine-derived structure (Va) and the tetracarboxylic dianhydride-derived structure (IVa) form an imide bond to form an imide structural unit represented by general formula (I), the diamine-derived structure (Va) and the dicarboxylic acid-derived structure (VIa) form an amide bond to form an amide structural unit represented by general formula (II), and the anhydride carboxyl group portion and carboxyl group portion of the tricarboxylic acid anhydride-derived structure (VIIa) form an imide bond and an amide bond, respectively, to the diamine-derived structure (Va), to form an amide-imide structural unit represented by general formula (III). When the amide-imide structural unit represented by general formula (III) is formed, a structure corresponding to the tetracarboxylic dianhydride-derived structure, such as general formula (III'), is also generated. (In general formula (III'), X is a tetravalent organic group, Y is a divalent organic group, and W is a trivalent organic group.)

[0028] [ka]

[0029] [ka]

[0030] The polyamide-imide may contain multiple types of tetracarboxylic dianhydride residues X, multiple types of diamine residues Y, multiple types of dicarboxylic acid residues Z, and multiple types of tricarboxylic acid anhydride residues W.

[0031] As will be detailed later, polyamide-imides are generally obtained by synthesizing polyamic acids using polybasic acid derivatives such as diamines, tetracarboxylic dianhydrides, and dicarboxylic acid dichlorides and tricarboxylic acid anhydride chlorides as monomers, and then dehydrating and cyclizing the amide acid at the bond between the tetracarboxylic or tricarboxylic acid and the diamine. Polybasic acid derivatives such as dicarboxylic acid dichlorides and tricarboxylic acid anhydride chlorides are used as starting monomers, but the resulting polyamide-imides have a structure Z (dicarboxylic acid residue) obtained by removing two carboxyl groups from the dicarboxylic acid, or a structure W obtained by removing three carboxyl groups from the tricarboxylic acid. Regardless of the type of starting material (monomer) used in the synthesis of polyamide-imides, the structure corresponding to the tetracarboxylic dianhydride residue X contained in the polyamide-imide is referred to as the "tetracarboxylic dianhydride component," the structure corresponding to the diamine residue Y is referred to as the "diamine component," and the structure corresponding to the dicarboxylic acid residue Z and the tricarboxylic acid anhydride residue W are referred to as the "polybasic acid component."

[0032] Below, we will explain, with examples, the diamine component, tetracarboxylic dianhydride component, and polybasic acid component as monomer units that constitute polyamide-imide.

[0033] <Diamine> (Specific diamines) The polyamide of the present invention has CF3-O-,-(CF2-O) as its diamine component. n -, and -O-(CF2-CF2-O) n -Includes a diamine having one or more structures selected from the following. n is an integer from 1 to 20. Hereinafter, these diamines will be referred to as "specific diamines".

[0034] In certain diamines, the carbon atom of the trifluoromethyl group (-CF3) or the carbon atom of the difluoromethylene group (-CF2-) is bonded to an oxygen atom. Compared to structures where the trifluoromethyl group is bonded to a carbon atom (-C-CF3) or structures where carbon atoms are bonded to both ends of the difluoromethylene group (-C-CF2-C-), these diamines tend to be more biodegradable and have lower environmental persistence. Therefore, polyamide-imides containing certain diamines as the diamine component are more environmentally safe than conventional soluble polyamide-imides containing organofluorine compounds such as fluoroalkyl-substituted benzidines as the diamine component.

[0035] Among the specific diamines, those that do not fall under the "specific fluorine structure" described later are CF3-O- or -(CF2-O) n Diamines having a trifluoromethoxy group (CF3-O-) are preferred from the viewpoint of polymerizability and mechanical strength of polyamide-imides, and among these, diamines in which the oxygen atom of the trifluoromethoxy group is bonded to the carbon atom of the aromatic ring are preferred. Examples of specific diamines in which the trifluoromethoxy group is bonded to the carbon atom of the aromatic ring include trifluoromethoxy-substituted benzidine and trifluoromethoxy-substituted phenylenediamine.

[0036] Examples of trifluoromethoxy-substituted benzidines include 2-(trifluoromethoxy)benzidine, 3-(trifluoromethoxy)benzidine, 2,3-bis(trifluoromethoxy)benzidine, 2,5-bis(trifluoromethoxy)benzidine, 2,6-bis(trifluoromethoxy)benzidine, 2,3,5-tris(trifluoromethoxy)benzidine, 2,3,6-tris(trifluoromethoxy)benzidine, 2,3,5,6-tetrakis(trifluoromethoxy)benzidine, 2,2'-bis(trifluoromethoxy)benzidine (TFMOB), 3,3'-bis(trifluoromethoxy)benzidine, and 2,3'-bis(trifluoromethoxy)benzidine. Examples include 0(trifluoromethoxy)benzidine, 2,2',3-tris(trifluoromethoxy)benzidine, 2,3,3'-tris(trifluoromethoxyl)benzidine, 2,2',5-tris(trifluoromethoxy)benzidine, 2,2',6-tris(trifluoromethoxy)benzidine, 2,3',5-tris(trifluoromethoxy)benzidine, 2,3',6-tris(trifluoromethoxy)benzidine, 2,2',3,3'-tetrakis(trifluoromethoxy)benzidine, 2,2',5,5'-tetrakis(trifluoromethoxy)benzidine, and 2,2',6,6'-tetrakis(trifluoromethoxy)benzidine.

[0037] Examples of trifluoromethoxy-substituted phenylenediamines include 1,2-diamino-4-(trifluoromethoxy)benzene, 1,3-diamino-4-(trifluoromethoxy)benzene, 1,4-diamino-2-(trifluoromethoxy)benzene, 1,4-diamino-2,3-bis(trifluoromethoxy)benzene, 1,4-diamino-2,5-bis(trifluoromethoxy)benzene, 1,4-diamino-2,6-bis(trifluoromethoxy)benzene, 1,4-diamino-2,3,5-tris(trifluoromethoxy)benzene, and 1,4-diamino-2,3,5,6-tetrakis(trifluoromethoxy)benzene.

[0038] From the viewpoint of polymerizability and mechanical strength of polyamide-imides, trifluoromethoxy-substituted benzidines are preferred as specific diamines. Among these, from the viewpoint of solubility in organic solvents and compatibility with other resins, those having a trifluoromethoxy group at the 2nd or 3rd position of biphenyl are preferred, with 2,2'-bis(trifluoromethoxy)benzidine (hereinafter referred to as "TFMOB"), 3,3'-bis(trifluoromethoxy)benzidine, and 2,3'-bis(trifluoromethoxy)benzidine being more preferred, and TFMOB being particularly preferred. By having a trifluoromethoxy group at the 2nd or 3rd position of biphenyl, in addition to the decrease in π electron density due to the electron-withdrawing properties of the trifluoromethoxy group, π-π stacking between benzene rings is inhibited due to the steric hindrance of the trifluoromethoxy group, so the absorption edge wavelength is shifted to a shorter wavelength, and the coloration of the polyamide-imide can be reduced. Furthermore, TFMOB reduces the coloration of polyamide-imide because the steric hindrance between the trifluoromethoxy groups at the 2 and 2' positions of biphenyl causes the bond between the two benzene rings of biphenyl to twist, reducing the planarity of the π-conjugated structure. This causes the absorption edge wavelength to shift to a shorter wavelength.

[0039] The amount of specific diamine relative to the total amount of diamine components is preferably 10 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, and may be 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 mol% or more, or even 100 mol%. In particular, it is preferable that the amount of trifluoromethoxy group-containing diamine be within this range, and especially preferable that the amount of trifluoromethoxy-substituted benzidine be within this range. The higher the ratio of specific diamine, the more the discoloration is suppressed, and the mechanical strength of the film, such as pencil hardness, elastic modulus, breaking strength, and elongation at break, may improve.

[0040] (Diamines other than specified diamines) Polyamide-imides may contain diamines other than specified diamines as diamine components. From the viewpoint of environmental safety of polyamide-imides, those that do not contain -C-CF3 and -C-CF2-C- are preferred, and those that do not contain fluorine atoms are particularly preferred.

[0041] Examples of diamines that do not contain a fluorine atom include 2,2'-dimethylbenzidine, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di(3-aminophenyl)propane, 2,2-di(4-aminophenyl)propane, 2-(3-aminophenyl)-2 -(4-aminophenyl)propane, 1,1-di(3-aminophenyl)-1-phenylethane, 1,1-di(4-aminophenyl)-1-phenylethane, 1-(3-aminophenyl)-1-(4-aminophenyl)-1-phenylethane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminobenzoyl)benzene, 1,3-bis(4-aminobenzoyl)benzene , 1,4-bis(3-aminobenzoyl)benzene, 1,4-bis(4-aminobenzoyl)benzene, 1,3-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,3-bis(4-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene, 2,6-bis(3-aminophenoxy)benzonitrile, 2,6-bis(3-aminophenoxy)pyridine, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-Bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 2,2-bis[4-( 3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)-α,α-dimethyl [Benzyl]benzene, 1,4-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-aminophenoxy)-α,α-dimethylbenzyl]benzene, 4,4'-bis[4-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenylsulfone, 4,4'-bis[4-(4-aminophenoxy)phenoxy]diphenyl Lusulfone, 3,3'-diamino-4,4'-diphenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobindan, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobindan, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 1,3-Bis(4-aminobutyl)tetramethyldisiloxane, α,ω-bis(3-aminopropyl)polydimethylsiloxane, α,ω-bis(3-aminobutyl)polydimethylsiloxane, bis(aminomethyl) ether, bis(2-aminoethyl) ether, bis(3-aminopropyl) ether, bis(2-aminomethoxy)ethyl ether, bis[2-(2-aminoethoxy)ethyl] ether, bis[2-(3-aminoprothoxy)ethyl] ether, 1,2-bis(aminomethoxy)ethane, 1,2-bis(2-aminoethoxy)ethane, 1,2-bis[2-(aminomethoxy)ethoxy]ethane, 1,2-bis[2-(2-aminoethoxy)ethoxy]ethane, ethylene glycol bis(3-aminopropyl) ether, diethylene glycol bis(3-aminopropyl) ether, triethylene glycol bis(3-aminopropyl) Ether, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexa Examples include trans-1,4-diaminocyclohexane, 1,2-di(2-aminoethyl)cyclohexane, 1,3-di(2-aminoethyl)cyclohexane, 1,4-di(2-aminoethyl)cyclohexane, bis(4-aminocyclohexyl)methane, isophoronediamine, 2,6-bis(aminomethyl)bicyclo[2.2.1]heptane, 2,5-bis(aminomethyl)bicyclo[2.2.1]heptane, etc.

[0042] In addition to specific diamines, using diaminodiphenylsulfone as the diamine may improve the solubility and transparency of the polyamide-imide resin in the solvent. Among diaminodiphenylsulfones, 3,3'-diaminodiphenylsulfone (3,3'-DDS) and 4,4'-diaminodiphenylsulfone (4,4'-DDS) are preferred, and these may be used in combination.

[0043] When diaminodiphenylsulfone is used in addition to specific diamines, the amount of diaminodiphenylsulfone relative to the total amount of diamine components may be 1 to 80 mol%, 3 to 60 mol%, or 5 to 30 mol%.

[0044] In addition to specific diamines, using diamines having a fluorene structure as the diamine may improve the solubility in solvents, transparency, and mechanical strength of the polyamide-imide resin. Preferred fluorene-containing diamines include 9,9-bis(4-aminophenyl)fluorene, 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, and 9,9-bis(4-amino-3-methylphenyl)fluorene, and these may be used in combination.

[0045] When using a diamine having a fluorene structure in addition to a specific diamine, the amount of the diamine having a fluorene structure relative to the total amount of the diamine component may be 1 to 80 mol%, 3 to 60 mol%, or 5 to 30 mol%.

[0046] In addition to specific diamines, using alicyclic diamines as diamines may improve the transparency of polyamide-imides. Among alicyclic diamines, isophorone diamine and 1,4-diaminocyclohexane are preferred, and these may be used in combination.

[0047] When using alicyclic diamines in addition to specific diamines, the amount of alicyclic diamine relative to the total amount of diamine components may be 1-70 mol%, 3-50 mol%, 5-40 mol%, 10-30 mol%, or 12-25 mol%.

[0048] The total amount of specific diamines, diaminodiphenylsulfone, diamines having a fluorene structure, and alicyclic diamines relative to the total amount of diamine components in polyamide-imide is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and may also be 95 mol% or more or 99 mol% or more, or even 100 mol%.

[0049] Polyamide-imides may contain fluorine-containing diamines other than specified diamines as diamine components. However, from the viewpoint of environmental safety of polyamide-imides, the amount of fluorine-containing diamines other than specified diamines relative to the total amount of diamine components of polyamide-imides is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and may be 5 mol% or less, 1 mol% or less, or 0.5 mol% or less. Polyamide-imides may also not contain fluorine-containing diamines other than specified diamines as diamine components.

[0050] Among fluorine atom-containing diamines, those having a structure in which a trifluoromethyl group is bonded to a carbon atom (-C-CF3) and / or a structure in which carbon atoms are bonded to both ends of a difluoromethylene group (-C-CF2-C-) have low degradability and raise concerns about environmental safety. From the viewpoint of improving the transparency and solubility of polyamide-imides, general soluble polyamide-imides contain diamines as diamine components that have a structure in which CF3- or -C(CF3)2- is directly bonded to the carbon atom of the aromatic ring (for example, trifluoromethoxy-substituted benzidines such as 2,2'-bis(trifluoromethyl)benzidine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane). However, from the viewpoint of the environmental safety of polyamide-imides, it is preferable that they substantially do not contain these diamines. The amount of diamine in which CF3- or -C(CF3)2- is directly bonded to the carbon atom of the aromatic ring, relative to the total amount of diamine components in the polyamide-imide, is preferably less than 0.5 mol%, and may be 0.3 mol% or less, 0.1 mol% or less, or 0.05 mol% or less, or even 0.

[0051] <Tetracarboxylic acid dianhydride> (Specified acid dianhydride) The acid dianhydride component of the polyamideimide is not particularly limited, but from the viewpoint of enhancing environmental safety and imparting solubility in organic solvents, as the acid dianhydride component, it preferably contains one or more acid dianhydrides selected from the group consisting of acid dianhydrides having an ether bond, bis(trimellitic anhydride) ester, acid dianhydrides having a fluorene structure, and acid dianhydrides having a xanthene structure. Hereinafter, these acid dianhydrides are referred to as "specific acid dianhydrides".

[0052] Examples of the acid dianhydride having an ether bond include those in which two phthalic anhydrides are bonded via an ether bond (-O-) or a functional group containing an ether bond. Examples of the acid dianhydride in which two phthalic anhydrides are bonded via an ether bond include 3,4'-oxydiphthalic anhydride (a-ODPA) and 4,4'-oxydiphthalic anhydride (s-ODPA).

[0053] Examples of the functional group containing an ether bond include a bisphenol derivative structure. Examples of the acid dianhydride in which two phthalic anhydrides are bonded via a bisphenol derivative structure include the compound represented by the following general formula (1).

[0054] [Chemical formula]

[0055] In general formula (1), A is an arbitrary divalent organic group, and p is 1 or 2. R 1a , R 1b , R 2a and R 2b are each independently an arbitrary substituent, m1 and m2 are each independently an integer from 0 to 3, and n1 and n2 are each independently an integer from 0 to 4.

[0056] Examples of the divalent organic group A include the following (a), (b), and (c). R 3a and R 3bEach of these is independently a hydrogen atom, a C1-C10 alkyl group, or a phenyl group. (b) R 4 R is an alkyl group having 1 to 10 carbon atoms, and k is an integer from 0 to 10. If k is 2 or greater, multiple R 4 They may be the same or they may be different.

[0057] [ka]

[0058] Substituent R 1a and R 1b , and substituent R 2a and R 2b Examples include alkyl groups having 1 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, phenyl groups, and halogens.

[0059] From the viewpoint of solubility of polyamide-imide resins, the acid dianhydride having an ether bond is preferably one represented by general formula (1), and among these, 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic acid anhydride (BPADA) is particularly preferred.

[0060] Bis(trimellitic anhydride) esters are represented by the following general formula (2).

[0061] [ka]

[0062] In general formula (2), X is any divalent organic group, with carboxyl groups bonded to the carbon atoms of X at both ends. The carbon atoms bonded to the carboxyl groups may form a ring structure. Specific examples of divalent organic groups X are listed below (A) to (K).

[0063] [ka]

[0064] R in equation (A) 1 m is an alkyl group having 1 to 20 carbon atoms or a fluorine atom, and m is an integer from 0 to 4. The group represented by formula (A) is a hydroquinone which may have substituents on the benzene ring, with two hydroxyl groups removed. Examples of hydroquinone derivatives having substituents on the benzene ring include tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, and 2,5-di-tert-amylhydroquinone.

[0065] R in equation (B) 2 n is an alkyl group having 1 to 20 carbon atoms or a fluorine atom, and n is an integer from 0 to 4. The group represented by formula (B) is a biphenol which may have substituents on the benzene ring, with two hydroxyl groups removed. Examples of biphenol derivatives having substituents on the benzene ring include 2,2'-dimethylbiphenyl-4,4'-diol, 3,3'-dimethylbiphenyl-4,4'-diol, 3,3',5,5'-tetramethylbiphenyl-4,4'-diol, and 2,2',3,3',5,5'-hexamethylbiphenyl-4,4'-diol.

[0066] The group represented by formula (C) is the group obtained by removing two hydroxyl groups from 4,4'-isopropylidenediphenol (bisphenol A). The group represented by formula (D) is the group obtained by removing two hydroxyl groups from resorcinol.

[0067] In formula (E), p is an integer between 1 and 10. The group represented by formula (E) is a straight-chain diol with 1 to 10 carbon atoms from which two hydroxyl groups have been removed. Examples of straight-chain diols with 1 to 10 carbon atoms include ethylene glycol and 1,4-butanediol.

[0068] The group represented by formula (F) is the group obtained by removing two hydroxyl groups from 1,4-cyclohexanedimethanol.

[0069] R in equation (G) 3X is a hydrogen atom, a fluorine atom, and an alkyl group having 1 to 20 carbon atoms, and q is an integer from 0 to 4. The group represented by formula (G) is a group obtained by removing two hydroxyl groups from bisphenol fluorene, which may have substituents on a benzene ring having phenolic hydroxyl groups. Examples of bisphenol fluorene derivatives having substituents on a benzene ring having phenolic hydroxyl groups include biscresol fluorene. When X has the structure of formula (G), it falls under both acid dianhydrides having a fluorene structure and bis(trimellitic anhydride) esters, but for the classification of specific acid dianhydrides, it is classified as a bis(trimellitic anhydride) ester. Furthermore, a compound in formula (1) where X has the structure of formula (J) falls under any of acid dianhydrides having a fluorene structure, acid dianhydrides having a xanthene structure, and bis(trimellitic anhydride) esters, but for the classification of specific acid dianhydrides, it is classified as a bis(trimellitic anhydride) ester.

[0070] The bis(trimellitic anhydride) ester is preferably an aromatic ester. Of the above (A) to (K), (A), (B), (C), (D), (G), (H), and (I) are preferred as X. Among these, (A) to (D) are preferred, and the group having a biphenyl skeleton of (B) is particularly preferred. When X is a group represented by general formula (B), from the viewpoint of the solubility of the polyamide-imide resin, X is preferably biphenylene or 2,2',3,3',5,5'-hexamethylbiphenyl-4,4'-diyl represented by the following formula (B1).

[0071] [ka]

[0072] The acidic dianhydride in general formula (2) where X is biphenylene is bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-biphenyl-4,4'diyl. The acidic dianhydride in general formula (2) where X is the group represented by formula (B1) is bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-2,2',3,3',5,5'-hexamethylbiphenyl-4,4'diyl (TAHMBP), represented by the following formula (3).

[0073] [ka]

[0074] Preferred bis(trimellitic anhydride) esters in which X in general formula (2) is a structure other than that of formula (B) include p-phenylenebis(trimellitic anhydride monoester) (TMHQ), bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-biphenyl-4,4'-diyl (OCBP-TME), 5,5'-(3,3'-dimethyl[1,1'-biphenyl]-4,4'-diyl)bis(1,3-dihydro-1,3-dioxo-5-isobenzofuran carboxylate) (BP-TME), tert-butylhydroquinone bis(trimellitate anhydride) (TA.BHQ), and trimethylhydroquinone bis(trimellitate anhydride) (TA.TMHQ).

[0075] From the viewpoint of polyamide-imide solubility, TMHQ, TAHMBP, and OCBP-TME are particularly preferred as bis(trimellitic anhydride) esters.

[0076] Examples of acid dianhydrides having a fluorene structure include 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride (BPF-PA), N,N'-(9H-fluorene-9-ylidenedi-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzofrancarboxamide] (FDA-ATA), and 5,5'-(9H-fluorene-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzofrancarboxylate] (TBIS.MPN). From the viewpoint of polyamide-imide solubility, BPAF, BPF-PA, or TBIS.MPN are preferred, and among these, BPAF or BPF-PA are particularly preferred.

[0077] Examples of acid dianhydrides having a xanthene structure include 5,5'-spiro[9H-fluorene-9,9'-[9H]xanthene]-3',6'-diirbis(1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylate (TBIS.RXN), spiro[fluorene-9,9'xanthene]-2',3',6',7'-tetracarboxylic dianhydride (SFDA), etc. Although these example compounds contain both xanthene and fluorene structures, they are classified as acid dianhydrides having a xanthene structure.

[0078] Polyamide-imides containing the aforementioned specific diamine as the diamine component and a specific acid dianhydride as the acid dianhydride component tend to be soluble in organic solvents and possess high transparency and mechanical strength.

[0079] From the viewpoint of solubility in organic solvents and transparency, among specific acid dianhydrides, 4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride (BPADA), 3,4'-oxydiphthalic anhydride (a-ODPA), 4,4'-oxydiphthalic anhydride (s-ODPA), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride (BPF-PA), 5,5'-(9H-fluorene-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzofuran carboxylate](TBIS.MPN), spiro[fluorene -9,9'xanthene]-2',3',6',7'-tetracarboxylic dianhydride (SFDA), 5,5'-spiro[9H-fluorene-9,9'-[9H]xanthene]-3',6'-diylbis(1,3-dihydro-1,3-dioxo-5-isobenzofuran carboxylate), p-phenylenebis(trimellitic acid monoester anhydride) (TMHQ), bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-biphenyl-4,4'diyl (OCBP-TME), and bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-2,2',3,3',5,5'-hexamethylbiphenyl-4,4'diyl (TAHMBP) are preferred.

[0080] From the viewpoint of UV resistance of polyamide-imides, among the specific acid dianhydrides, acid dianhydrides having ether bonds, acid dianhydrides having a fluorene structure, and acid dianhydrides having a xanthene structure are preferred. From the viewpoint of solubility in solvents and mechanical strength, BPADA, α-ODPA, α-ODPA, BPAF, BPF-PA, and SFDA are particularly preferred. These acid dianhydrides do not have ester bonds and do not undergo fleece transition due to UV light, so discoloration is less likely to occur when polyamide-imides are exposed to UV light. Furthermore, from the viewpoint of compatibility with polycarbonates, which will be discussed later, acid dianhydrides having ether bonds, acid dianhydrides having a fluorene structure, and acid dianhydrides having a xanthene structure are preferred as specific acid dianhydrides.

[0081] From the viewpoint of making polyamide-imide soluble in organic solvents, the total amount of specific acid dianhydrides relative to the total amount of acid dianhydrides is preferably 15 mol% or more, more preferably 20 mol% or more, even more preferably 25 mol% or more, and may be 30 mol% or more, 35 mol% or more, 40 mol% or more, 45 mol% or more, 50 mol% or more, or 60 mol% or more. The total amount of specific acid dianhydrides relative to the total amount of acid dianhydrides may be 100 mol%, and may be 95 mol% or less, 90 mol% or less, 85 mol% or less, 80 mol% or less, 75 mol% or less, or 70 mol% or less.

[0082] (Acid dianhydrides other than specified acid dianhydrides) Polyamide-imides may contain acid dianhydrides other than specific acid dianhydrides as acid dianhydrides. Examples of such acid dianhydrides include alicyclic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. From the viewpoint of environmental safety of polyamide-imides, those that do not contain -C-CF3 and -C-CF2-C- are preferred, and those that do not contain fluorine atoms are particularly preferred.

[0083] Alicyclic tetracarboxylic dianhydrides only need to have at least one alicyclic structure, and may have both an alicyclic and an aromatic ring in one molecule. The alicyclic may be polycyclic and may have a spiro structure. Examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and 1,1'-bicyclohexane-3,3',4,4'tetracarboxylic acid-3,4:3', 4'-Dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic dianhydride, 2,2'-binorbornane-5,5',6,6'tetracarboxylic dianhydride, 3-(carboxymethyl)-1,2,4-cyclopentanetricarboxylic acid-1,4:2,3-dianhydride, bicyclo[2.2.2]octa-7-en-2,3,5,6-tetracarboxylic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, cyclohexane-1,4-diylbis(methylene)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate), 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 5,5'-[cyclohexylidenebis(4,1-phenyleneoxy)]bis-1,3-isobenzofrandione, 5-isobenzofurancarboxylic acid,1, 3-Dihydro-1,3-Dioxo-,5,5'-[1,4-Cyclohexanediylbis(methylene)] ester, Bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, Bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 3,5,6-Tricarboxynorbornane-2-acetic acid 2,3:5,6-dianhydride, Decahydro-1,4,5,8-Dimethanonaphthalene-2,3,6,7-tetracarboxylic dianhydride, Tricyclo[6.4.0.Examples include 0(2,7) dodecane-1,8:2,7-tetracarboxylic dianhydride, octahydro-1H,3H,8H,10H-biphenyleno[4a,4b-c:8a,8b-c']difuran-1,3,8,10-tetraone, ethylene glycol bis(hydrogenated trimellitic anhydride) ester, decahydro[2]benzopyrano[6,5,4,-def][2]benzopyran-1,3,6,8-tetraone, etc. The inclusion of alicyclic tetracarboxylic dianhydrides in addition to specific acid dianhydrides as acid dianhydride components tends to improve the mechanical strength of polyamide-imides. Furthermore, the inclusion of alicyclic tetracarboxylic dianhydrides as acid dianhydride components in polyamide-imides tends to increase the compatibility between polyamide-imides and polycarbonates.

[0084] Among alicyclic tetracarboxylic dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA-100), bicyclo[2.2.2]octa-7-ene-2,3,5,6-tetracarboxylic dianhydride (BEDA), bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride (BODA), and 1,1'-bicyclohexane-3,3',4,4'tetracarboxylic dianhydride-3,4:3',4'-dianhydride (H-BPDA) are preferred from the viewpoint of transparency and mechanical strength of the polyamide-imide. In particular, from the viewpoint of mechanical strength, tetracarboxylic anhydrides in which two acid anhydride groups are bonded to one alicyclic ring are preferred, and CBDA is especially preferred.

[0085] When using alicyclic tetracarboxylic dianhydrides in addition to specific acid dianhydrides, the amount of alicyclic tetracarboxylic dianhydrides relative to the total amount of acid dianhydrides may be 1 mol% or more, 3 mol% or more, 5 mol% or more, 10 mol% or more, 12 mol% or more, or 15 mol% or more. The higher the amount of alicyclic tetracarboxylic dianhydrides, the higher the mechanical strength tends to be. From the viewpoint of ensuring the solubility of polyamide-imide in organic solvents, the amount of alicyclic tetracarboxylic dianhydrides relative to the total amount of acid dianhydrides is preferably 80 mol% or less, more preferably 60 mol% or less, even more preferably 50 mol% or less, and may be 40 mol% or less, 30 mol% or less, or 20 mol% or less. Furthermore, polyamide-imides containing alicyclic tetracarboxylic dianhydrides within the above ranges as acid dianhydrides tend to have excellent compatibility with polycarbonates.

[0086] Aromatic tetracarboxylic dianhydrides other than specific acid dianhydrides include pyromellitic acid dianhydride (PMDA), 1,2,3,4-benzenetetracarboxylic dianhydride (MPDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), and 2,2',3,3'-biphenyltetracarboxylic dianhydride. Examples include phenyltetracarboxylic dianhydride (i-BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 5,5'-dimethylmethylenebis(phthalic anhydride), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, terphenyltetracarboxylic dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, and bis(3,4-dicarboxyphenyl)sulfone dianhydride. Among these aromatic tetracarboxylic dianhydrides, a-BPDA, s-BPDA, i-BPDA, PMDA, MPDA, and DSDA are preferred from the viewpoint of improving mechanical strength.

[0087] When using aromatic tetracarboxylic dianhydrides other than the specified acid dianhydrides in addition to the specified acid dianhydrides, the amount of aromatic tetracarboxylic dianhydrides other than the specified acid dianhydrides relative to the total amount of acid dianhydrides may be 1 mol% or more, 3 mol% or more, 5 mol% or more, 10 mol% or more, 12 mol% or more, or 15 mol% or more. From the viewpoint of ensuring the solubility of polyamide-imide in organic solvents, the amount of aromatic tetracarboxylic dianhydrides other than the specified acid dianhydrides relative to the total amount of acid dianhydrides is preferably 80 mol% or less, more preferably 60 mol% or less, even more preferably 50 mol% or less, and may also be 40 mol% or less, 30 mol% or less, or 20 mol% or less.

[0088] Polyamide-imide may contain linear aliphatic tetracarboxylic dianhydrides as acid dianhydride components, such as ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, and meso-butane-1,2,3,4-tetracarboxylic dianhydride.

[0089] The amount of fluorine-containing dianhydride relative to the total amount of dianhydride components in polyamide-imide is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and may also be 5 mol% or less, 1 mol% or less, or 0.5 mol% or less. Polyamide-imide may also not contain fluorine-containing dianhydride as an acid dianhydride component.

[0090] Among fluorine atom-containing acid dianhydrides, those having a structure in which a trifluoromethyl group is bonded to a carbon atom (-C-CF3) and / or a structure in which carbon atoms are bonded to both ends of a difluoromethylene group (-C-CF2-C-) have low degradability and raise concerns about environmental safety. In particular, acid dianhydrides having a structure in which CF3- or -C(CF3)2- is directly bonded to a carbon atom of an aromatic ring (e.g., 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 9,9-bis(trifluoromethyl)xanthenetetracarboxylic acid dianhydride, 9-trifluoromethylxanthenetetracarboxylic acid dianhydride) have low environmental degradability, so from the viewpoint of the environmental safety of polyamide-imides, it is preferable that they substantially do not contain these acid dianhydrides. The amount of acid dianhydride in which CF3- or -C(CF3)2- is directly bonded to the carbon atom of the aromatic ring, relative to the total amount of acid dianhydride components of the polyamide-imide, is preferably less than 0.5 mol%, and may be 0.3 mol% or less, 0.1 mol% or less, or 0.05 mol% or less, or even 0.

[0091] The polyamide-imide contains one or more acidic dianhydrides (specific acidic dianhydrides) selected from tetracarboxylic dianhydrides having a fluorene structure, tetracarboxylic dianhydrides having a xanthene structure, tetracarboxylic dianhydrides having an ether linkage, and bis(trimellitic anhydride) esters as tetracarboxylic dianhydrides, and from the viewpoint of compatibility, the total ratio of the structure derived from tetracarboxylic dianhydrides having a fluorene structure, tetracarboxylic dianhydrides having a xanthene structure, tetracarboxylic dianhydrides having an ether linkage, and bis(trimellitic anhydride) esters to the total amount of structure derived from tetracarboxylic dianhydrides is preferably 40 to 100 mol%, more preferably 50 to 100 mol%, and even more preferably 70 to 100 mol%.

[0092] (polybasic acid) As described above, by using dicarboxylic acids and / or tricarboxylic anhydrides as polybasic acid components in addition to diamines and tetracarboxylic dianhydrides, polyamide-imides containing a dicarboxylic acid-derived structure represented by general formula (VIa) and / or a tricarboxylic anhydride-derived structure represented by general formula (VIIa) can be obtained.

[0093] Examples of dicarboxylic acids include aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-oxybisbenzoic acid, 4,4'-biphenyldicarboxylic acid, and 2-fluoroterephthalic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-hexahydroterephthalic acid, hexahydroisophthalic acid, 1,3-cyclopentanedicarboxylic acid, and bi(cyclohexyl)-4,4'-dicarboxylic acid; and heterocyclic dicarboxylic acids such as 2,5-thiophenedicarboxylic acid and 2,5-franzicarboxylic acid.

[0094] Examples of tricarboxylic acid anhydrides include trimellitic anhydride, 2-fluorotrimellitic anhydride, 5-fluorotrimellitic anhydride, 6-fluorotrimellitic anhydride, 2,5-difluorotrimellitic anhydride, 2,6-difluorotrimellitic anhydride, 5,6-difluorotrimellitic anhydride, and 2,5,6-trifluorotrimellitic anhydride, as well as other trimellitic anhydride derivatives.

[0095] From the viewpoint of polyamide-imide solubility, preferred polybasic acids are aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and trimellitic anhydride, with aromatic dicarboxylic acids being particularly preferred. Among aromatic dicarboxylic acids, terephthalic acid, isophthalic acid, 4,4'-biphenyldicarboxylic acid, and 4,4'-oxybisbenzoic acid are preferred, with terephthalic acid and isophthalic acid being particularly preferred, and terephthalic acid being particularly preferred. Among alicyclic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid and bi(cyclohexyl)-4,4'-dicarboxylic acid are preferred, with 1,4-cyclohexanedicarboxylic acid being particularly preferred.

[0096] In the preparation of polyamide-imides and polyamic acids as precursors, polybasic acid derivatives such as dicarboxylic acid dichlorides, dicarboxylic acid esters, dicarboxylic acid anhydrides, and tricarboxylic acid anhydride chlorides may be used instead of polybasic acids.

[0097] <Ratio of amide structures in polyamide-imides> Preferably, the polyamide-imide contains 90 to 110 mole parts of the total structure derived from the tetracarboxylic dianhydride represented by general formula (IVa), the dicarboxylic acid represented by general formula (VIa), and the tricarboxylic acid anhydride represented by general formula (VIIa) relative to 100 mole parts of the diamine-derived structure represented by general formula (Va). The total of the structure of general formula (IVa), general formula (VIa), and general formula (VIIa) may be 93 to 107 mole parts, 95 to 105 mole parts, 97 to 103 mole parts, or 99 to 101 mole parts relative to 100 mole parts of the structure of general formula (Va).

[0098] The ratio of the structure of general formula (VIa) to the sum of the structures of general formula (VIIa) is between 1 and 99 mol%. The ratio of the structure of general formula (IVa) to the structure of general formula (VIa) is approximately equal to the ratio of the imide structure of general formula (I) to the amide structure of general formula (II), and the ratio of the structure of general formula (IVa) to the structure of general formula (VIIa) is approximately equal to the ratio of the imide structure of general formula (I) to the amide-imide structure of general formula (III). The ratio of the structure of general formula (VIa) to the total of the structure of general formula (VIIa) to the total of the structure of general formula (IVa), the structure of general formula (VIa), and the structure of general formula (VIIa) may be 5 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, or 50 mol% or more, and may be 80 mol% or less, 75 mol% or less, 70 mol% or less, 65 mol% or less, or 60 mol% or less.

[0099] The higher the proportion of structures of general formulas (VIa) and (VIIa), i.e., the higher the proportion of amide structures, the more likely it is that the solubility of polyamide-imides in organic solvents will improve.

[0100] The amount of polybasic acid relative to the diamine component of the polyamide-imide used in this embodiment, that is, the total ratio of structural units of general formula (VI) and general formula (VII) to structural units of general formula (V), may be 5 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, or 50 mol% or more, and may be 80 mol% or less, 75 mol% or less, 70 mol% or less, 65 mol% or less, or 60 mol% or less.

[0101] <Content of specific fluorine structures in polyamide-imides> As mentioned above, the diamine components are CF3-O-, -(CF2-O) n -, and -O-(CF2-CF2-O) n Polyamide-imides containing diamines (specific diamines) having one or more structures selected from - exhibit solubility in organic solvents without substantially containing structures such as -C-CF3, -C-CF2-C-.

[0102] To reduce the environmental persistence of fluorine-containing compounds, it is preferable that polyamide-imides use a small amount of monomers having specific fluorine structures. Specific fluorine structures are those obtained by excluding structures containing only the components of structural formula (i) below from those having a trifluoromethyl group (CF3-), and those obtained by excluding structures containing only the components of structural formula (ii) below from those having a difluoromethylene group (-CF2-). CF3-X (i) X-CF2-X' (ii)

[0103] In formulas (i) and (ii), X is -OR or -NRR', and in formula (ii), X' is one of -H, -CH3, aromatic, -C(O)-, -OR'', -SR'', and NR''R'''. R, R', R'', and R'''' are each independently one of -H, -CH3, -CH2-, aromatic, or -C(O)-.

[0104] From the viewpoint of improving environmental degradability, the amount of fluorine atoms contained in the specific fluorine structure per 1 kg of polyamideimide is preferably less than 500 mg, more preferably less than 300 mg, even more preferably less than 100 mg, and particularly preferably less than 50 mg.

[0105] <Preparation of polyamide-imides> The method for preparing polyamideimides is not particularly limited. Generally, polyamide acids are prepared as polyamideimide precursors by reacting diamines with tetracarboxylic dianhydrides and polybasic acids or their derivatives, and polyamideimides are obtained by dehydrating and cyclizing (imidizing) the polyamide acids. As described above, by adjusting the monomer composition constituting the polyamideimide, i.e., the types and ratios of acid dianhydrides, polybasic acids or their derivatives, and diamines, polyamideimides with solubility in organic solvents and transparency can be obtained.

[0106] The method for preparing polyamic acid is not particularly limited, and any known method can be applied. For example, a polyamic acid solution can be obtained by dissolving an acidic dianhydride and a polybasic acid or its derivative in an organic solvent such that the total amount is approximately equimolar to the diamine (molar ratio of 90:100 to 110:100), and then stirring. The concentration of the polyamic acid solution is usually 5 to 35% by weight, preferably 10 to 30% by weight. When the concentration is within this range, the polyamic acid obtained by polymerization has an appropriate molecular weight, and the polyamic acid solution has an appropriate viscosity.

[0107] In the polymerization of polyamic acids, it is preferable to add the dianhydride to the diamine to suppress ring-opening of the dianhydride. When adding multiple types of diamines or dianhydrides, they may be added all at once or in multiple steps. The properties of the polyamide-imide can also be controlled by adjusting the order of monomer addition.

[0108] The organic solvent used for polymerization of polyamic acid is not particularly limited, as long as it does not react with diamines and acidic dianhydrides and can dissolve polyamic acid. Examples of organic solvents include urea-based solvents such as methylurea and N,N-dimethylethylurea; sulfoxide or sulfone-based solvents such as dimethyl sulfoxide, diphenyl sulfone, and tetramethylsulfone; amide-based solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), N,N'-diethylacetamide, N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, and hexamethylphosphate triamide; alkyl halide-based solvents such as chloroform and methylene chloride; aromatic hydrocarbon-based solvents such as benzene and toluene; and ether-based solvents such as tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether, and p-cresol methyl ether. These solvents are usually used individually or in appropriate combinations of two or more as needed. From the viewpoint of polyamic acid solubility and polymerization reactivity, DMAc, DMF, NMP, etc., are preferably used.

[0109] Polyamide-imide can be obtained by dehydration cyclization of polyamic acid. One method for preparing polyamide-imide from a polyamic acid solution is to add a dehydrating agent, an imidation catalyst, etc., to the polyamic acid solution and allow imidation to proceed in the solution. To accelerate the progression of imidation, the polyamic acid solution may be heated. By mixing the solution containing the polyamide-imide produced by the imidation of polyamic acid with a poor solvent, the polyamide-imide resin precipitates as a solid. By isolating the polyamide-imide resin as a solid, impurities generated during the synthesis of polyamic acid, as well as residual dehydrating agents and imidation catalysts, can be washed and removed with the poor solvent, preventing discoloration and increased yellowness of the polyamide-imide. Furthermore, by isolating the polyamide-imide resin as a solid, solvents suitable for film formation, such as low-boiling point solvents, can be applied when preparing the solution for film production.

[0110] The molecular weight of the polyamide-imide (weight-average molecular weight in terms of polyethylene oxide, measured by gel filtration chromatography (GPC)) is preferably 10,000 to 1,000,000, more preferably 20,000 to 500,000, and even more preferably 40,000 to 300,000. If the molecular weight is too low, the film strength may be insufficient. If the molecular weight is too high, the solubility of the polyamide-imide resin and its compatibility with other resins may be poor.

[0111] Polyamide-imides are preferably soluble in organic solvents. Specifically, polyamide-imides are preferably soluble in dimethylformamide (DMF) at 23°C at a concentration of 1% by weight or more. In addition to being soluble in amide solvents such as DMF, polyamide-imides are preferably soluble in non-amide solvents. Examples of non-amide solvents include ketone solvents such as acetone and methyl ethyl ketone, alkyl halide solvents such as chloroform and dichloromethane, and ester solvents such as ethyl acetate and γ-butyrolactone. Non-amide solvents have lower boiling points compared to amide solvents, and residual solvents are easily removed during film production; therefore, polyamide-imides soluble in non-amide solvents can be expected to improve film productivity. Polyamide-imides are particularly preferably soluble in methylene chloride.

[0112] [Resin composition] The polyamide-imide of the present invention exhibits solubility in organic solvents and compatibility with other resins. In particular, the polyamide-imide of the present invention has high compatibility with polycarbonate and can be used as a resin composition containing polyamide-imide and polycarbonate.

[0113] <Polycarbonate> Polycarbonate refers to a polymer in which monomer units are linked by carbonate bonds (-O-(C=O)-O-). From the viewpoint of transparency, it is preferable that the monomer units, specifically 50 mol% or more of the total monomers as the main component, have a bisphenol structure such as bisphenol A, bisphenol AP, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, bisphenol Z, and it is more preferable that bisphenol A is present.

[0114] The preferred weight-average molecular weight of polycarbonate is 5,000 to 200,000, more preferably 10,000 to 100,000, and even more preferably 50,000 to 100,000, from the viewpoint of balancing compatibility with polyamide-imide and the strength of the molded article. Furthermore, using polycarbonate with a weight-average molecular weight of 50,000 or more tends to improve mechanical strength. Specifically, TEIJIN's Panlight AD-5503, K-1300Y, L-1225L, L-1225LM, L-1225Y, L-1225Z100, L-1225Z100M, L-1225ZL100, L-1250Y, L-1250Z100, LD-1000RM, LN-1010RM, LN-2250Y, LN-2250Z, LN-2520A, LN-2520HA, LN-2525ZA, LN-3000RM, LN-3050RM, LS-2250, LV-2225L, LV-2225Y, LV-2225Z, LV-2250Y, LV-22 Examples include 50Z, MN-4800, MN-4800Z, MN-4805Z, Yupiron K4100, ML200, ML300, ML400 from Mitsubishi Engineering Plastics, APEC1695, APEC1697, APEC1795, APEC1797, APEC1895, APEC1897, APEC2095, APEC2097, APEC9351, APEC9371 from Covestro, and PCZ-200, FPC-0820, FPC-0220, FPC8225, FPC2136, FPC0330, FPC-F124 from Mitsubishi Gas Chemical.

[0115] As raw material monomers for constituting polycarbonate without losing the effects of the present invention, 1,2-bis(4-hydroxyphenyl)ethane, 2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane, 1,2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-ethyl-4-hydroxyphenyl)propane, 2,2-bis(3-n-propyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxyphenyl) 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2,2-bis(3-allyl-4-hydroxyphenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl) hydroxyphenyl) sulfoxide, bis(4-hydroxyphenyl) sulfone, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 6,6'-dihydroxy-3,3,3',3'-tetramethylspiro(bis)indan, 2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxyanthrene, 2,7-dihydroxyphenoxatine, 2,7-dihydroxy-9,10-dimethylphenazine, 3,6-dihydroxybenzofuran, 3,6-dihydro It may contain xyanthrene, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,2'-dimethylbiphenyl-4,4'-diol, 3,3'-dimethylbiphenyl-4,4'-diol, isopropylidenediphenol, 3,3',5,5'-tetramethylbiphenyl-4,4'-diol, 2,2',3,3',5,5'-hexamethylbiphenyl-4,4'-diol, resorcinol, etc.

[0116] Furthermore, the X in general formula (4) can include an annular structure to the extent that the effects of the present invention are not lost. X can include fluorene skeletons, phthalimide skeletons, and alicyclic skeletons such as cyclohexylmethylidene, 1,1-ethene, 2-[2.2.1]-bicycloheptylidene, cyclohexylidene, cyclopentylidene, cyclododecylidene, and adamantylidene. Specifically, examples of dihydric alcohols constituting polycarbonates include 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 3,3-bis(4-hydroxyphenyl)phthalimidine, 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, and 4,4'-(3,3,5-trimethylcyclohexylidene)diphenol.

[0117] [ka]

[0118] From the viewpoint of the heat resistance of the film, the glass transition temperature of polycarbonate is preferably 100°C or higher, more preferably 120°C or higher, and may be 150°C or higher or 180°C or higher.

[0119] <Preparation of a resin composition containing polyamide-imide and polycarbonate> A resin composition is prepared by mixing the above-mentioned polyamide-imide resin and polycarbonate. Since the above-mentioned polyamide-imide resin and polycarbonate can be compatible in any ratio, the ratio of polyamide-imide resin to polycarbonate in the resin composition is not particularly limited. The mixing ratio (weight ratio) of polyamide-imide resin to polycarbonate may be 98:2 to 2:98, 95:5 to 10:90, or 90:10 to 15:85. The higher the proportion of polyamide-imide resin, the higher the elastic modulus of the film tends to be, and the better the mechanical strength tends to be. The higher the proportion of polycarbonate, the less coloration the film tends to have and the higher its transparency tends to be.

[0120] In order to fully realize the effect of improving transparency by mixing polyamide-imide and polycarbonate, the ratio of polycarbonate to the total of polyamide-imide and polycarbonate is preferably 10% by weight or more, and may be 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, 40% by weight or more, 45% by weight or more, or 50% by weight or more.

[0121] Polyamide-imides are polymers with a unique molecular structure. Generally, they have low solubility in organic solvents and are incompatible with other polymers. However, as mentioned above, polyamide-imides containing specific diamine and acid dianhydride components exhibit high solubility in organic solvents and compatibility with polycarbonates.

[0122] Resin compositions containing polyamide-imide resin and polycarbonate preferably have a single glass transition temperature in differential scanning calorimetry (DSC) and / or dynamic viscoelasticity measurement (DMA). When a resin composition has a single glass transition temperature, the polyamide-imide resin and polycarbonate can be considered to be perfectly miscible. Films containing polyamide-imide resin and polycarbonate also preferably have a single glass transition temperature.

[0123] The resin composition may simply be a mixture of polyamide-imide resin and polycarbonate precipitated as solid components, or it may be a mixture of polyamide-imide and polycarbonate. Alternatively, when precipitating the polyamide-imide resin by mixing the polyamide-imide solution with a poor solvent, polycarbonate may be mixed into the solution to precipitate a resin composition of polyamide-imide and polycarbonate as a solid (powder).

[0124] The resin composition may be a mixed solution containing polyamide-imide resin and polycarbonate. The method of mixing the resins is not particularly limited; they may be mixed in a solid state or mixed in a liquid state to form a mixed solution. A polyamide-imide resin solution and a polycarbonate solution may be prepared separately, and then the two may be mixed to prepare a mixed solution of polyamide-imide resin and polycarbonate.

[0125] The solvent for a solution containing polyamide-imide resin and polycarbonate is not particularly limited as long as it is soluble in both the polyamide-imide resin and polycarbonate. Examples of solvents include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; ether solvents such as tetrahydrofuran and 1,4-dioxane; ketone solvents such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, diethyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone; and alkyl halogenated solvents such as chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chlorobenzene, dichlorobenzene, and methylene chloride.

[0126] In terms of the solubility of polyamide-imide and the compatibility between polyamide-imide and polycarbonate in solution, amide-based solvents are preferred. On the other hand, in terms of the ease of solvent removal when producing molded articles such as films, low-boiling-point non-amide-based solvents are preferred. Ketone-based solvents and alkyl halogenated solvents are preferred because they have excellent solubility for both polyamide-imide and polycarbonate, have low boiling points, and allow for easy removal of residual solvent during film production.

[0127] The resin composition may contain organic or inorganic low-molecular-weight compounds, high-molecular-weight compounds (e.g., epoxy resins), etc. The resin composition may also contain flame retardants, ultraviolet absorbers, crosslinking agents, dyes, pigments, surfactants, leveling agents, plasticizers, fine particles, sensitizers, etc. The fine particles may include organic fine particles such as polystyrene and polytetrafluoroethylene, and inorganic fine particles such as colloidal silica, carbon, and layered silicates, and may have a porous or hollow structure. The fiber reinforcing material may include carbon fibers, glass fibers, aramid fibers, etc.

[0128] Resin compositions containing polyamide-imide and polycarbonate tend to have lower melt viscosity compared to polyamide-imide alone, resulting in excellent moldability in injection molding, transfer molding, press molding, and melt extrusion molding. Furthermore, solutions of resin compositions containing polyamide-imide and polycarbonate tend to have lower solution viscosity compared to solutions of polyamide-imide alone at the same solid content concentration. Therefore, they offer excellent handling properties, such as easier transport of the solution, high coating properties, and advantages in reducing film thickness variations.

[0129] Molded articles formed from a resin composition containing polyamide-imide and polycarbonate from a solution tend to have a lower glass transition temperature compared to molded articles formed from a solution of the same polyamide-imide alone. Therefore, when processed under the same heating conditions, the amount of residual solvent in the molded article tends to be lower. In particular, when using high-boiling point amide solvents, high-temperature heating of 250°C or above or 300°C or above may be required to remove the solvent, which can result in a decrease in the transparency of the resulting molded article. However, by using a resin composition containing polyamide-imide and polycarbonate, the amount of residual solvent can be reduced with shorter heating times, thus suppressing discoloration during heating and making it easier to obtain molded articles with high transparency.

[0130] [Molded articles and films] The above-mentioned polyamide-imide and resin compositions containing polyamide-imide and polycarbonate can be used to form various molded articles. Molding methods include injection molding, transfer molding, press molding, blow molding, inflation molding, calendering, and melt extrusion molding.

[0131] In one embodiment, the molded body is a film. The film can be formed by either a melting method or a solution method, but the solution method is preferred from the viewpoint of producing a film with excellent transparency and uniformity. In the solution method, a film is obtained by coating a solution containing the above-mentioned polyamide-imide onto a support and drying off the solvent. Since the above-mentioned polyamide-imide and polycarbonate are compatible in solution, it is possible to produce a highly transparent film by the solution method by using polyamide-imide and polycarbonate in combination.

[0132] As a method for applying the resin solution onto the support, known methods using bar coaters, comma coaters, etc., can be applied. As the support, glass substrates, metal substrates such as SUS, metal drums, metal belts, plastic films, etc., can be used. From the viewpoint of improving productivity, it is preferable to use an endless support such as a metal drum or metal belt, or a long plastic film, as the support and manufacture the film by roll-to-roll. When using a plastic film as the support, a material that does not dissolve in the film-forming doping solvent should be appropriately selected.

[0133] Heating is preferable when drying the solvent. The heating temperature is not particularly limited as long as it can remove the solvent and suppress discoloration of the resulting film, and can be appropriately set between room temperature and approximately 250°C, with 50°C to 220°C being preferred. The heating temperature may be increased in stages. To improve the efficiency of solvent removal, the resin film may be peeled from the support and dried after a certain degree of drying has progressed. Heating may be performed under reduced pressure to promote solvent removal.

[0134] The film may be stretched in one or more directions for purposes such as improving its mechanical strength. When a film is stretched, the polymer chains orient themselves in the direction of stretching, which improves the in-plane strength of the film and tends to suppress the occurrence of cracks and fissures.

[0135] Films used as cover films or substrate materials for foldable displays require high mechanical strength in the direction perpendicular to the bending axis, as they are repeatedly folded along the same point at the same location. Therefore, by arranging the film so that its stretching direction is perpendicular to the bending axis, cracks and breaks are less likely to occur at the folding point even after repeated folding, providing a device with high bending resistance.

[0136] The stretching conditions for the film are not particularly limited. For example, the stretching temperature is approximately ±40°C of the film's glass transition temperature. The stretching temperature may also be approximately 120-300°C, 150-250°C, or 180-230°C.

[0137] The stretching ratio is approximately 1-200%, but may also be 5-150%, 10-120%, or 20-100%. A higher stretching ratio tends to result in a higher tensile modulus in the stretching direction. In particular, in compatible systems of polyamide-imide and polycarbonate, the tensile modulus in the stretching direction increases, and this tends to improve bending resistance. The higher the proportion of methyl methacrylate in the monomer components of polycarbonate, the more pronounced the increase in the tensile modulus in the stretching direction becomes. If the stretching ratio is excessively high, the mechanical strength in the direction perpendicular to the stretching direction tends to decrease, which may reduce the handling properties of the film.

[0138] From the viewpoint of increasing strength in any direction within the plane, the film may be biaxially stretched. Biaxial stretching may be simultaneous biaxial stretching or sequential biaxial stretching. In biaxial stretching, the stretching ratio in one direction and the stretching ratio in the direction perpendicular to it may be the same or different. If there is a difference in the stretching ratio, the mechanical strength tends to be relatively higher in the direction with the larger stretching ratio. When using a biaxially stretched film with anisotropic stretching ratio in a foldable device, it is preferable to position the direction with the larger stretching ratio perpendicular to the folding axis.

[0139] The film thickness is not particularly limited and can be set appropriately depending on the application. For example, the film thickness is 5 to 300 μm. From the viewpoint of achieving both self-supporting properties and flexibility, and a highly transparent film, the film thickness is preferably 20 μm to 200 μm, but may also be 30 μm to 150 μm, 40 μm to 100 μm, or 50 μm to 80 μm. For use as a cover film for displays, the film thickness is preferably 10 μm or more. When stretching the film, it is preferable that the thickness after stretching is within the above range.

[0140] The haze of the film is preferably 10% or less, more preferably 5% or less, even more preferably 4% or less, and may be 3.5% or less, 3% or less, 2% or less, or 1% or less. The lower the haze of the film, the better. As described above, since polyamide-imide and polycarbonate are compatible, a film containing polyamide-imide and polycarbonate has low haze and excellent transparency, similar to a film made of polyamide-imide alone.

[0141] The total light transmittance of the film is preferably 87% or higher, more preferably 88% or higher, and may be 89% or higher or 90% or higher. A film containing polyamide-imide and polycarbonate has a higher total light transmittance than a film made of polyamide-imide alone, and can exhibit a total light transmittance of 90% or higher.

[0142] The yellowness of the film is not particularly limited, but the yellowness (YI) of the film is preferably 10 or less, more preferably 5.0 or less, and may be 4.0 or less, 3.0 or less, 2.0 or less, 1.5 or less, or 1.0 or less. Films containing polyamide-imide and polycarbonate have a lower YI compared to films containing polyamide-imide alone, even when the YI of a film containing polyamide-imide alone exceeds 10. By adopting a mixed system with polycarbonate, it is possible to reduce the YI. Films containing polyamide-imide and polycarbonate can achieve a low YI of 1.0 or less.

[0143] From the viewpoint of strength, the tensile modulus of the film is preferably 2.5 GPa or higher, more preferably 3.0 GPa or higher, and may also be 4.0 GPa or higher. The pencil hardness of the film is preferably 6B or higher, more preferably 4B or higher, even more preferably B or higher, and may also be H or higher, 2H or higher, or 3H or higher. In a compatible system of polyamide-imide and polycarbonate, the pencil hardness tends not to decrease even when the proportion of polycarbonate is increased. Therefore, it is possible to provide a film with less discoloration and excellent transparency without significantly reducing the excellent mechanical strength characteristic of polyamide-imide.

[0144] The polyamide-imide film of the present invention is suitable for use as a display material because it has little coloration and high transparency. In particular, films with high mechanical strength can be applied to surface components such as cover windows of displays. Furthermore, since polyamide-imide substantially does not contain specific fluorine structures, it is highly biodegradable and environmentally safe. For practical use, the film of the present invention may be provided with an antistatic layer, an easy-adhesion layer, a hard coat layer, an anti-reflective layer, etc. on its surface. [Examples]

[0145] The embodiments of the present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following embodiments.

[0146] [Preparation of polyamide-imide resin] Dimethylformamide (DMF) was placed in a separable flask and stirred under a nitrogen atmosphere. Diamine, tetracarboxylic dianhydride, and polybasic acid derivatives were then added in the proportions shown in Table 1 and stirred under a nitrogen atmosphere for 5 to 10 hours to react and obtain a polyamic acid solution with a solid content of 10% by weight.

[0147] To 100 g of polyamic acid solution, 5.5 g of pyridine was added as an imidation catalyst and completely dispersed. Then, 8 g of acetic anhydride was added, and the mixture was stirred at 90°C for 3 hours to carry out imidation.

[0148] After cooling the imidized solution to room temperature, 100g of 2-propyl alcohol (hereinafter referred to as IPA) was added at a rate of 2-3 drops / second while stirring to precipitate polyamide-imide. Further 150g of IPA was added, and after stirring for approximately 30 minutes, suction filtration was performed using a Kiriyama funnel. The resulting solid was washed with IPA and then dried in a vacuum oven set to 120°C for 12 hours to obtain polyamide-imide resin.

[0149] [Film production example] <Examples 1-4, Comparative Examples 1-2> A DMF solution with a resin content of 10% by weight was prepared by mixing dimethylformamide (DMF) with polyamide-imide (PAI) obtained in the above example of polyamide-imide resin production and commercially available polycarbonate PCZ-200 (manufactured by Mitsubishi Gas Chemical, glass transition temperature = 175°C, hereafter PC1) or FPC-2136 (manufactured by Mitsubishi Gas Chemical, weight-average molecular weight = 61,000, glass transition temperature = 131°C, hereafter PC2) in a 50:50 weight ratio. This solution was applied to an alkali-free glass plate and heated and dried in an air atmosphere for 15 minutes at 60°C, 90°C, 15 minutes at 120°C, 15 minutes at 150°C, 15 minutes at 180°C, and 15 minutes at 200°C to produce a film.

[0150] [Film Evaluation] <Haze and total light transmittance> The film was cut into 3cm squares, and the haze and total light transmittance (TT) were measured using a Suga Test Instruments HZ-V3 haze meter in accordance with JIS K7136 and JIS K7361-1.

[0151] <Total light transmittance> The film was cut into 3cm squares, and the total light transmittance (TT) was measured using a Suga Test Instruments HZ-V3 haze meter in accordance with JIS K7136 and JIS K7361-1.

[0152] <Yellowness> The film was cut into 3cm squares, and the yellowness (YI) was measured according to JIS K7373 using a Suga Test Instruments SC-P spectrophotometer.

[0153] <Tensile modulus> The film was cut into strips 10 mm wide, allowed to stand for 1 day at 23°C / 55%RH to adjust humidity, and then the tensile modulus was measured using Shimadzu Corporation's "AUTOGRAPH AGS-X" under the following conditions. Distance between gripping parts: 100mm Tensile speed: 20.0 mm / min Measurement temperature: 23℃

[0154] [Evaluation Results] Table 1 shows the compositions of the polyamideimides in the examples and comparative examples, as well as the evaluation results of the polyamideimide films in the examples.

[0155] In Table 1, the composition of the polyamide-imide (diamine, tetracarboxylic dianhydride, and polybasic acid derivative) is shown as a molar ratio where the total amount of tetracarboxylic dianhydride and the total amount of polybasic acid derivative is 100 mole parts, and the compounds are indicated by the following abbreviations.

[0156] <Diamine> TFMOB: 2,2'-Bis(trifluoromethoxy)benzidine BAFL: 9,9-bis(4-aminophenyl)fluorene 4,4'-ODA:4,4'-diaminodiphenyl ether

[0157] <Acid dianhydride> BPADA: 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride TAHMBP: Bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-2,2',3,3',5,5'-hexamethylbiphenyl-4,4 'Jiil CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

[0158] <Polybasic acid derivatives> IPC: Isophthalate Dichloride TPC: Dichloride terephthalate TMAC: Trimellitus Chloride Anhydride

[0159] The polyamide-imides of Examples 1-4, which contained a specific diamine as the diamine component, were soluble in organic solvents and compatible with polycarbonate, allowing for the production of transparent films. On the other hand, Comparative Examples 1 and 2, which did not contain the specific diamine, were insoluble in organic solvents.

[0160] These results indicate that by using a specific diamine that does not contain a specific fluorine structure as the diamine component, a polyamide-imide with high environmental safety and excellent solubility and transparency in organic solvents can be obtained.

[0161] [Table 1]

Claims

1. A resin composition comprising polyamide-imide and polycarbonate, The polyamide-imide is a polyamide-imide having imide bonds and amide bonds, and having a structure derived from at least a tetracarboxylic dianhydride component and a diamine component. The aforementioned diamine is CF ３ -O-, -(CF ２ -O) ｎ -, -O-(CF ２ -CF ２ -O) ｎ A resin composition characterized by containing a diamine having one or more structures selected from any of the following (where n is an integer from 1 to 20).

2. The resin composition according to claim 1, characterized in that the tetracarboxylic dianhydride component includes one or more acidic dianhydrides selected from tetracarboxylic dianhydrides having an ether bond, tetracarboxylic dianhydrides having a fluorene structure, tetracarboxylic dianhydrides having a xanthene structure, and bis(trimellitic anhydride) esters.

3. One or more acidic dianhydrides selected from the ether-bonded tetracarboxylic dianhydrides, fluorene-containing tetracarboxylic dianhydrides, xanthene-containing tetracarboxylic dianhydrides, and bis(trimellitic anhydride) esters include 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride, 3,4'-oxydiphthalic anhydride, 4,4'-oxydiphthalic anhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, and 5,5'-(9H-fluorene-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzo The resin composition according to claim 2, comprising at least one of the following: lancarboxylate, spiro[fluorene-9,9'xanthene]-2',3',6',7'-tetracarboxylic dianhydride, 5,5'-spiro[9H-fluorene-9,9'-[9H]xanthene]-3',6'-diylbis(1,3-dihydro-1,3-dioxo-5-isobenzofuran carboxylate, p-phenylenebis(trimellitic acid monoester anhydride), bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-biphenyl-4,4'diyl, and bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-2,2',3,3',5,5'-hexamethylbiphenyl-4,4'diyl.

4. The above CF ３ -O-, -(CF ２ -O) ｎ -, -O-(CF ２ -CF ２ -O) ｎ - selected diamine having a structure (where n is an integer from 1 to 20) is selected from 2,2'-bis(trifluoromethoxy)benzidine, 3,3'-bis(trifluoromethoxy)benzidine, 2,3'-bis(trifluoromethoxy)benzidine, The resin composition according to claim 1, characterized in that

5. CF directly connected to the aromatic ring of the aforementioned polyamide-imide ３ - Directly attached to the group or aromatic ring - C (CF ３ ) ２ The content of tetracarboxylic dianhydride components having - is less than 0.5 mol% of the total tetracarboxylic dianhydride components. CF directly connected to the aromatic ring of the polyamide-imide resin composition ３ - Directly attached to the group or aromatic ring - C (CF ３ ) ２ The resin composition according to claim 1, characterized in that the content of the diamine component having - is less than 0.5 mol% of the total diamine components.

6. The resin composition according to claim 2, wherein the polyamide-imide comprises, as a tetracarboxylic dianhydride, one or more acid dianhydrides selected from tetracarboxylic dianhydrides having a fluorene structure, tetracarboxylic dianhydrides having a xanthene structure, tetracarboxylic dianhydrides having an ether linkage, and bis(trimellitic anhydride) ester, and the total ratio of the structure derived from tetracarboxylic dianhydrides having a fluorene structure, the structure derived from tetracarboxylic dianhydrides having a xanthene structure, the structure derived from tetracarboxylic dianhydrides having an ether linkage, and the structure derived from bis(trimellitic anhydride) ester to the total amount of structure derived from tetracarboxylic dianhydrides is 50 to 100 mol%.

7. The resin composition according to claim 1, characterized in that the glass transition temperature (Tg) of the polycarbonate is 150°C or higher.

8. The resin composition according to claim 1, characterized in that the weight-average molecular weight (Mw) of the polycarbonate is 50,000 or more.

9. The resin composition according to claim 1, wherein the polyamide-imide and the polycarbonate are in a composition ratio (weight ratio) in the range of 2:98 to 98:

2.

10. A molded article comprising the resin composition according to any one of claims 1 to 9.

11. A film comprising the resin composition according to any one of claims 1 to 9.

Images