Polyamidimide, resin composition, molded article, and film

Abstract

The present invention relates to a polyamidimide and a resin composition comprising a polyamidimide and an acrylic resin. The polyamidimide comprises a diamine component, a tetracarboxylic dianhydride component, and a polybasic acid component, wherein the diamine component includes a diamine that has one or more structures selected from CF3-O-, -(CF2-O)n-, and -O-(CF2-CF2-O)n- (where n is an integer of 1-20). The diamine is preferably 2,2'-bis(trifluoromethoxy)benzidine, 3,3'-bis(trifluoromethoxy)benzidine, 2,3'-bis(trifluoromethoxy)benzidine, or the like.

Description

Polyamideimide, resin composition, molded article and film

[0001] The present invention relates to a polyamideimide, a resin composition containing the polyamideimide, and a molded article such as a film.

[0002] There is a demand for thinner, lighter, and more flexible electronic devices, such as display devices including liquid crystal displays, organic electroluminescence displays, and electronic paper, as well as solar cells and touch panels. By replacing the glass materials used in these devices with film materials, flexibility, thinner, and lighter devices can be achieved. Transparent polyimide films have been developed as glass replacement materials and are used for display substrates, cover films, and the like. Patent Document 1 proposes using polyamideimide as a material for cover films for flexible displays.

[0003] A method for producing a highly transparent polyamideimide film has been proposed that uses a polyamideimide resin that is soluble in organic solvents and does not require high-temperature imidization after film formation. Such soluble polyamideimides use fluorine-containing compounds as the diamine and / or tetracarboxylic dianhydride monomers to balance transparency and mechanical properties. For example, the polyamideimide disclosed 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 and other properties of the film can be improved by mixing a soluble polyamideimide with an acrylic resin.

[0005] International Publication No. WO 2013 / 048126 International Publication No. WO 2023 / 132310

[0006] In recent years, the environmental persistence of organic fluorine compounds (PFAS) has become a problem. In general, the carbon-fluorine bond contained in organic fluorine compounds has high bond energy and is difficult to decompose in the environment. In particular, the structure in which a trifluoromethyl group is bonded to a carbon atom (-C-CF ３ ), or a structure in which carbon atoms are bonded to both ends of a difluoromethylene group (—C—CF ２ Organic fluorine compounds containing fluorine atoms (C) have low decomposition properties in the environment and have been reported to have adverse effects on the human body.

[0007] In view of the above problems, an object of the present invention is to provide a polyamideimide that is environmentally safe, soluble in organic solvents, and highly transparent, as well as a resin composition containing the polyamideimide, and a molded article such as a film.

[0008] The present invention relates to a polyamideimide and a resin composition containing the polyamideimide and an acrylic resin. The polyamideimide contains CF as a diamine component. ３ -O-, -(CF ２ -O) ｎ -, and -O-(CF ２ -CF ２ -O) ｎ - (CF ２ -O) ｎ -, and -O-(CF ２ -CF ２ -O) ｎ In the -, n is an integer of 1 to 20.

[0009] Preferred examples of the specific diamine that is a fluorine atom-containing diamine include 2,2'-bis(trifluoromethoxy)benzidine, 3,3'-bis(trifluoromethoxy)benzidine, and 2,3'-bis(trifluoromethoxy)benzidine.

[0010] The polyamide-imide preferably contains, as a tetracarboxylic acid dianhydride component, one or more tetracarboxylic acid dianhydrides (specific acid dianhydrides) selected from the group consisting of tetracarboxylic acid dianhydrides having an ether bond, tetracarboxylic acid dianhydrides having a fluorene structure, tetracarboxylic acid dianhydrides having a xanthene structure, and bis(trimellitic anhydride) esters.

[0011] Preferred examples of the specific acid dianhydride include 4,4'-(4,4'-isopropylidenediphenoxy)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, 5,5'-(9H-fluoren-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylate], spiro[fluorene-9,9'xanthene]-2',3 1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylate, 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] The polyamideimide may contain a diamine other than the specific diamine as the diamine component, and may contain a tetracarboxylic acid dianhydride other than the specific acid dianhydride as the tetracarboxylic acid dianhydride component.

[0013] Examples of tetracarboxylic dianhydrides other than the specific acid dianhydrides include 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, and 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride.

[0014] The tetracarboxylic acid dianhydride other than the specific acid dianhydride may be an alicyclic tetracarboxylic acid dianhydride. Examples of the alicyclic tetracarboxylic acid dianhydride include 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic acid dianhydride, and 1,1'-bicyclohexane-3,3',4,4'tetracarboxylic acid-3,4:3',4'-dianhydride. The amount of the alicyclic tetracarboxylic dianhydride relative to the total amount of the tetracarboxylic dianhydride components in the polyamideimide may be 1 to 80 mol %.

[0015] Polyamideimide is a compound in which the carbon atoms of the aromatic ring are CF ３ - or -C(CF ３ ) ２ The amount of diamine having a structure in which - is directly bonded is less than 0.5 mol %, and the amount of CF on the carbon atom of the aromatic ring is less than 0.5 mol % based on the total amount of the tetracarboxylic dianhydride component. ３ - or -C(CF ３ ) ２ The amount of tetracarboxylic dianhydride having a structure in which - is directly bonded is preferably less than 0.5 mol %.

[0016] The polyamideimide is preferably soluble in dimethylformamide at 23°C.

[0017] The resin composition of the present invention contains the above-mentioned polyamide and an acrylic resin. The resin composition may contain the polyamideimide and the acrylic resin in a weight ratio ranging from 98:2 to 2:98.

[0018] The polyamideimide and resin composition described above can be applied to molded articles such as films.

[0019] Polyamideimides containing specific diamines as diamine components have excellent solubility in organic solvents and transparency. Furthermore, since the specific diamines have lower environmental persistence than organic fluorine compounds such as fluoroalkyl-substituted benzidines, the polyamideimides of the present invention have excellent environmental safety.

[0020] [Polyamideimide] Polyamideimide is a polymer having an imide structural unit represented by general formula (I), an amide structural unit represented by general formula (II), and / or an amideimide structural unit represented by general formula (III).

[0021]

[0022] 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. Y is a diamine residue, which is an organic group obtained by removing two amino groups from a diamine represented by the following general formula (V). X is a tetracarboxylic dianhydride (hereinafter sometimes referred to as "acid dianhydride") residue, which is an organic group obtained by removing two carboxy anhydride groups from a tetracarboxylic dianhydride represented by the following general formula (IV). Z is a dicarboxylic acid residue, which is an organic group obtained by removing two carboxy groups from a dicarboxylic acid represented by the following general formula (VI). W is a tricarboxylic acid anhydride residue, which is an organic group obtained by removing a carboxy anhydride group and a carboxy group from a tricarboxylic acid anhydride represented by the following general formula (VII).

[0023]

[0024] In other words, the polyamide-imide contains 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 contains 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 the 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 the general formula (II), and the carboxy anhydride group moiety and the carboxy group moiety of the tricarboxylic acid anhydride-derived structure (VIIa) form an imide bond and an amide bond, respectively, with the diamine-derived structure (Va), to form an amide-imide structural unit represented by the general formula (III).

[0025]

[0026] The polyamideimide may contain multiple types of diamine residues Y, multiple types of tetracarboxylic dianhydride residues X, multiple types of dicarboxylic acid residues Z, or multiple types of tricarboxylic acid anhydride residues W.

[0027] As will be described in detail later, polyamideimides are generally obtained by synthesizing polyamic acids using diamines, tetracarboxylic dianhydrides, and polybasic acid derivatives such as dicarboxylic dichlorides and tricarboxylic anhydride chlorides as monomers, followed by cyclodehydration of the amic acids at the bond between the tetracarboxylic or tricarboxylic acid and the diamine. Polybasic acid derivatives such as dicarboxylic dichlorides and tricarboxylic anhydride chlorides are used as starting monomers, and the resulting polyamideimides have Structure Z (dicarboxylic acid residue) obtained by removing two carboxy groups from a dicarboxylic acid or Structure W obtained by removing three carboxy groups from a tricarboxylic acid. Regardless of the type of starting material (monomer) used in polyamideimide synthesis, the structure corresponding to the tetracarboxylic dianhydride residue X contained in the polyamideimide 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 structures corresponding to the dicarboxylic acid residue Z and the tricarboxylic anhydride residue W are referred to as the "polybasic acid component."

[0028] The diamine component, tetracarboxylic dianhydride component, and polybasic acid component as monomer units constituting polyamideimide will be described below with examples.

[0029] <Diamine> (Specific diamine) The polyamidimide of the present invention contains CF as a diamine component. ３ -O-, -(CF ２ -O) ｎ -, and -O-(CF ２ -CF ２ -O) ｎ -, wherein n is an integer of 1 to 20. Hereinafter, these diamines will be referred to as "specific diamines."

[0030] In certain diamines, a trifluoromethyl group (-CF ３ ) or a difluoromethylene group (—CF ２ The carbon atom of the alkyl group (-C-CF) is bonded to an oxygen atom, and a trifluoromethyl group is bonded to the carbon atom. ３ ) and a structure in which carbon atoms are bonded to both ends of a difluoromethylene group (—C—CF２ As a result, polyamideimides containing a specific diamine as a diamine component are superior in environmental safety to conventional soluble polyamideimides containing an organic fluorine compound such as a fluoroalkyl-substituted benzidine as a diamine component.

[0031] Among the specific diamines, CF does not fall under the category of "specific fluorine structure" described below. ３ -O-, or -(CF ２ -O) ｎ From the viewpoint of the polymerizability and mechanical strength of the polyamideimide, those having a trifluoromethoxy group (CF ３ -O-) is preferred, and among them, diamines in which the oxygen atom of the trifluoromethoxy group is bonded to a carbon atom of an aromatic ring are preferred. From the viewpoint of reactivity, diamines in which a trifluoromethoxy group is bonded to a carbon atom of an aromatic ring are preferably those which do not have a fluorine atom directly bonded to the aromatic ring to which the trifluoromethoxy group is bonded, and particularly preferred are those which do not contain fluorine atoms other than the trifluoromethoxy group. Examples of specific diamines in which a trifluoromethoxy group is bonded to a carbon atom of an aromatic ring include trifluoromethoxy-substituted benzidine and trifluoromethoxy-substituted phenylenediamine.

[0032] 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, 2,3'-bis(trif 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.

[0033] 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.

[0034] From the viewpoint of the polymerizability and mechanical strength of the polyamideimide, trifluoromethoxy-substituted benzidine is preferred as the specific diamine. Among them, from the viewpoint of the solubility of the polyamideimide resin in organic solvents and compatibility with other resins, those having a trifluoromethoxy group at the 2- or 3-position of the 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 2- or 3-position of the biphenyl, in addition to a decrease in π electron density due to the electron-withdrawing properties of the trifluoromethoxy group, the steric hindrance of the trifluoromethoxy group inhibits π-π stacking between benzene rings, thereby shifting the absorption edge wavelength to shorter wavelengths and reducing coloration of the polyamideimide. Furthermore, in the case of TFMOB, the steric hindrance between the trifluoromethoxy groups at the 2- and 2'-positions of the biphenyl causes the bond between the two benzene rings of the biphenyl to twist, reducing the planarity of the π-conjugation, thereby shifting the absorption edge wavelength to shorter wavelengths and reducing the coloration of the polyamideimide.

[0035] The amount of the specific diamine relative to the total amount of the 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%. Among these, the amount of the trifluoromethoxy group-containing diamine is preferably within this range, and the amount of the trifluoromethoxy-substituted benzidine is particularly preferably within this range. The higher the ratio of the specific diamine, the more suppressed the coloring and the mechanical strength of the film, such as pencil hardness, elastic modulus, breaking strength, and breaking elongation, may be improved.

[0036] (Diamines other than the specific diamines) The polyamideimide may contain diamines other than the specific diamines as the diamine component. ３ and -C-CF ２ Those which do not contain —C— are preferred, and those which do not contain a fluorine atom are particularly preferred.

[0037] Examples of diamines not containing fluorine atoms 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, and 3,4'-diaminodiphenyl sulfone. 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-amino phenyl)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-amino 2,2-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]benz 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-dimethylbenzyl]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]diphenyl sulfone, 4,4'-bis[4-(4-aminophenoxy)phenoxy]diphenyl sulfone, 3,3'-diamino-4,4'-diphenoxybenzophenone, 3,3 '-Diamino-4,4'-diviphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 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-aminoprotoxy)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-diaminocyclohexane, 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, and the like.

[0038] The use of diaminodiphenyl sulfone as the diamine in addition to the specific diamine may improve the solubility in solvents and transparency of the polyamide-imide resin. Among diaminodiphenyl sulfones, 3,3'-diaminodiphenyl sulfone (3,3'-DDS) and 4,4'-diaminodiphenyl sulfone (4,4'-DDS) are preferred, and these may be used in combination.

[0039] When diaminodiphenyl sulfone is used in addition to the specific diamine, the amount of diaminodiphenyl sulfone relative to the total amount of the diamine components may be 1 to 80 mol %, 3 to 60 mol %, or 5 to 30 mol %.

[0040] The use of a diamine having a fluorene structure in addition to the specific diamine as the diamine may improve the solubility in solvents, transparency, and mechanical strength of the polyamide-imide resin. Preferred fluorene-containing diamines are 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.

[0041] When a diamine having a fluorene structure is used in addition to the specific diamine, the amount of the diamine having a fluorene structure relative to the total amount of the diamine components may be 1 to 80 mol %, 3 to 60 mol %, or 5 to 30 mol %.

[0042] The transparency of the polyamideimide may be improved by using an alicyclic diamine in addition to the specific diamine. Among the alicyclic diamines, isophoronediamine and 1,4-diaminocyclohexane are preferred, and these may be used in combination.

[0043] When an alicyclic diamine is used in addition to the specific diamine, the amount of the alicyclic diamine relative to the total amount of the diamine components may be 1 to 70 mol %, 3 to 50 mol %, 5 to 40 mol %, 10 to 30 mol %, or 12 to 25 mol %.

[0044] The total amount of the specific diamine, diaminodiphenylsulfone, diamine having a fluorene structure, and alicyclic diamine relative to the total amount of diamine components in the polyamideimide is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and may be 95 mol% or more, 99 mol% or more, or even 100 mol%.

[0045] The polyamideimide may contain a fluorine atom-containing diamine other than the specific diamine as a diamine component, but from the viewpoint of environmental safety of the polyamideimide, the amount of the fluorine atom-containing diamine other than the specific diamine relative to the total amount of the diamine components of the polyamideimide 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. The polyamideimide may not contain a fluorine atom-containing diamine other than the specific diamine as a diamine component.

[0046] Among fluorine atom-containing diamines, the structure in which a trifluoromethyl group is bonded to a carbon atom (—C—CF ３ ) and / or a structure in which carbon atoms are bonded to both ends of a difluoromethylene group (—C—CF ２ In order to improve the transparency and solubility in solvents of polyamideimides, general soluble polyamideimides contain CF4 as a diamine component on the carbon atom of the aromatic ring. ３ - or -C(CF ３ ) ２ Although it contains diamines having a structure in which - is directly bonded (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), from the viewpoint of environmental safety of polyamideimides, it is preferable that these diamines are not substantially contained. ３ - or -C(CF ３ ) ２ The amount of diamine to which - is directly bonded 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 may be 0.

[0047] <Tetracarboxylic acid dianhydride> (Specific acid dianhydride) The acid dianhydride component of the polyamideimide is not particularly limited, but from the viewpoint of improving environmental safety and providing solubility in organic solvents, it is preferable that the acid dianhydride component contains one or more acid dianhydrides selected from the group consisting of acid dianhydrides having an ether bond, bis(trimellitic anhydride) esters, acid dianhydrides having a fluorene structure, and acid dianhydrides having a xanthene structure. Hereinafter, these acid dianhydrides will be referred to as "specific acid dianhydrides".

[0048] Examples of acid dianhydrides 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 acid dianhydrides 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).

[0049] An example of a functional group containing an ether bond is a bisphenol derivative structure. An example of an acid dianhydride in which two phthalic anhydrides are bonded via a bisphenol derivative structure is a compound represented by the following general formula (5):

[0050]

[0051] In general formula (5), A is any divalent organic group, and p is 1 or 2. １ａ , R １ｂ , R ２ａ and R ２ｂ are each independently an arbitrary substituent, m1 and m2 are each independently an integer of 0 to 3, and n1 and n2 are each independently an integer of 0 to 4.

[0052] Examples of the divalent organic group A include the following (a), (b), and (c). ３ａ and R ３ｂ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group. ４ is an alkyl group having 1 to 10 carbon atoms, and k is an integer of 0 to 10. When k is 2 or more, multiple R ４may be the same or different.

[0053]

[0054] Substituent R １ａ and R １ｂ , and the substituent R ２ａ and R ２ｂ Examples of the alkyl group include an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, and halogens.

[0055] From the viewpoint of the solubility of the polyamideimide resin, the acid dianhydride having an ether bond is preferably one represented by general formula (1), and among these, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA) is particularly preferred.

[0056] The bis(trimellitic anhydride) ester is represented by the following general formula (1).

[0057]

[0058] In general formula (1), X is any divalent organic group, and at both ends of X, a carboxy group and a carbon atom of X are bonded. The carbon atoms bonded to the carboxy group may form a ring structure. Specific examples of the divalent organic group X include the following (A) to (K).

[0059]

[0060] R in formula (A) １ is an alkyl group having 1 to 20 carbon atoms or a fluorine atom, and m is an integer of 0 to 4. The group represented by formula (A) is a group obtained by removing two hydroxyl groups from hydroquinone which may have a substituent on the benzene ring. Examples of hydroquinone derivatives having a substituent on the benzene ring include tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, and 2,5-di-tert-amylhydroquinone.

[0061] R in formula (B) ２is an alkyl group having 1 to 20 carbon atoms or a fluorine atom, and n is an integer of 0 to 4. The group represented by formula (B) is a group obtained by removing two hydroxyl groups from a biphenol which may have a substituent on the benzene ring. Examples of biphenol derivatives having a substituent 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.

[0062] The group represented by formula (C) is a group obtained by removing two hydroxyl groups from 4,4'-isopropylidenediphenol (bisphenol A). The group represented by formula (D) is a group obtained by removing two hydroxyl groups from resorcinol.

[0063] In formula (E), p is an integer of 1 to 10. The group represented by formula (E) is a group obtained by removing two hydroxyl groups from a linear diol having 1 to 10 carbon atoms. Examples of the linear diol having 1 to 10 carbon atoms include ethylene glycol and 1,4-butanediol.

[0064] The group represented by formula (F) is a group obtained by removing two hydroxyl groups from 1,4-cyclohexanedimethanol.

[0065] R in formula (G) ３is a hydrogen atom, a fluorine atom, or 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 bisphenolfluorene, which may have a substituent on the benzene ring having a phenolic hydroxyl group. Examples of bisphenolfluorene derivatives having a substituent on the benzene ring having a phenolic hydroxyl group include biscresolfluorene. When X has the structure of formula (G), the compound falls under both acid dianhydrides and bis(trimellitic anhydride) esters having a fluorene structure, but is classified as a bis(trimellitic anhydride) ester in terms of the specific acid dianhydride category. Furthermore, a compound in which X in formula (1) has the structure of formula (J) falls under both acid dianhydrides having a fluorene structure, acid dianhydrides having a xanthene structure, and bis(trimellitic anhydride) esters, but is classified as a bis(trimellitic anhydride) ester in terms of the specific acid dianhydride category.

[0066] 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 for X. Of these, (A) to (D) are preferred, with (B) being the group having a biphenyl skeleton being particularly preferred. When X is a group represented by general formula (B), from the viewpoint of the solubility of the polyamideimide resin, X is preferably biphenylene or 2,2',3,3',5,5'-hexamethylbiphenyl-4,4'-diyl represented by the following formula (B1):

[0067]

[0068] In the general formula (1), the acid dianhydride in which X is biphenylene is bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-biphenyl-4,4'-diyl. In the general formula (1), the acid dianhydride in which X is a 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).

[0069]

[0070] As the bis(trimellitic anhydride) ester in which X in the general formula (1) is a structure other than formula (B), p-phenylenebis(trimellitic acid monoester anhydride) (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-isobenzofurancarboxylate) (BP-TME), tert-butylhydroquinone bis(trimellitate anhydride) (TA.BHQ), trimethylhydroquinone bis(trimellitate anhydride) (TA.TMHQ), are preferred.

[0071] From the viewpoint of the solubility of polyamideimide, TMHQ, TAHMBP, and OCBP-TME are particularly preferred as the bis(trimellitic anhydride) ester.

[0072] 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-fluoren-9-ylidene-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxamide] ( FDA-ATA), 5,5'-(9H-fluoren-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylate] (TBIS.MPN), and the like. From the viewpoint of the solubility of polyamideimide, BPAF, BPF-PA, or TBIS.MPN are preferred, and among these, BPAF or BPF-PA is particularly preferred.

[0073] Examples of acid dianhydrides having a xanthene structure include 5,5'-spiro[9H-fluorene-9,9'-[9H]xanthene]-3',6'-diylbis(1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylate (TBIS.RXN) and spiro[fluorene-9,9'xanthene]-2',3',6',7'-tetracarboxylic dianhydride (SFDA). These exemplary compounds contain a xanthene structure and a fluorene structure, but are classified as acid dianhydrides having a xanthene structure.

[0074] Polyamideimides containing the above-mentioned specific diamine as the diamine component and the specific acid dianhydride as the acid dianhydride component tend to exhibit solubility in organic solvents and have high transparency and mechanical strength.

[0075] Among the specific acid dianhydrides, from the viewpoint of solubility in organic solvents and transparency, 4'-(4,4'-isopropylidenediphenoxy)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-fluoren-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxaphenyl]fluorene dianhydride ... so-5-isobenzofurancarboxylate] (TBIS.MPN), spiro[fluorene-9,9'xanthene]-2',3',6',7'-tetracarboxylic dianhydride (SFDA), 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.

[0076] From the viewpoint of UV resistance of polyamideimide, among the specific acid dianhydrides, acid dianhydrides having an ether bond, 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, a-ODPA, s-ODPA, BPAF, BPF-PA, and SFDA are particularly preferred. These acid dianhydrides do not have an ester bond and do not undergo Friess transition due to UV light, so polyamideimide is less likely to discolor when exposed to UV light. Furthermore, from the viewpoint of compatibility with the acrylic resin described below, acid dianhydrides having an ether bond, acid dianhydrides having a fluorene structure, and acid dianhydrides having a xanthene structure are preferred as the specific acid dianhydrides.

[0077] From the viewpoint of making the polyamideimide soluble in an organic solvent, the total amount of the specific acid dianhydride relative to the total amount of the acid dianhydride components 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, or 50 mol% or more. The total amount of the specific acid dianhydride relative to the total amount of the acid dianhydride components may be 100 mol%, or 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.

[0078] (Acid dianhydride other than the specific acid dianhydride) Polyamideimide may contain an acid dianhydride other than the specific acid dianhydride as the acid dianhydride component. Examples of such acid dianhydrides include alicyclic tetracarboxylic acid dianhydrides and aromatic tetracarboxylic acid dianhydrides. From the viewpoint of environmental safety of polyamideimide, -C-CF ３ and -C-CF ２ Those which do not contain —C— are preferred, and those which do not contain a fluorine atom are particularly preferred.

[0079] The alicyclic tetracarboxylic dianhydride may have at least one alicyclic structure, and may have both an alicyclic ring and an aromatic ring in one molecule. The alicyclic ring may be polycyclic or may have a spiro structure. Examples of the alicyclic tetracarboxylic dianhydride 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, 1,1'-bicyclohexane-3,3',4,4'tetracarboxylic acid-3,4:3',4'-dianhydride, and 1,1'-bicyclohexane-3,3',4,4'tetracarboxylic acid-3,4:3',4'-dianhydride. hydrate, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2"-norbornane-5,5",6,6"-tetracarboxylic acid dianhydride, 2,2'-binorbornane-5,5',6,6'tetracarboxylic acid dianhydride, 3-(carboxymethyl)-1,2,4-cyclopentanetricarboxylic acid-1,4:2,3-dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4- Tetrahydronaphthalene-1,2-dicarboxylic 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 anhydride, 5,5'-[cyclohexylidenebis(4,1-phenyleneoxy)]bis-1,3-isobenzofurandione, 5-isobenzofurancarboxylic acid, 1,3-dihydro-1,3-di Oxo-,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[6.4.0.0(2,7)]dodecane-1,8:2,Examples of suitable dianhydrides include 7-tetracarboxylic acid 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, and decahydro[2]benzopyrano[6,5,4,-def][2]benzopyran-1,3,6,8-tetraone. By including an alicyclic tetracarboxylic acid dianhydride in addition to a specific dianhydride as the dianhydride component, the mechanical strength of the polyamideimide tends to be improved. Furthermore, by including an alicyclic tetracarboxylic acid dianhydride as the dianhydride component in the polyamideimide, the compatibility of the polyamideimide with acrylic resins tends to be enhanced.

[0080] Among alicyclic tetracarboxylic dianhydrides, from the viewpoint of transparency and mechanical strength of polyamideimide, 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-tetracarboxylic dianhydride (P ... Tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA-100), bicyclo[2.2.2]oct-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 acid-3,4:3',4'-dianhydride (H-BPDA) are preferred. Among these, 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 particularly preferred.

[0081] When an alicyclic tetracarboxylic dianhydride is used in addition to the specific acid dianhydride, the amount of the alicyclic tetracarboxylic dianhydride relative to the total amount of the acid dianhydride components 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 greater the amount of alicyclic tetracarboxylic dianhydride, the higher the mechanical strength tends to be. From the viewpoint of ensuring the solubility of the polyamideimide in organic solvents, the amount of the alicyclic tetracarboxylic dianhydride relative to the total amount of the acid dianhydride components is preferably 80 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less, and may be 40 mol% or less, 30 mol% or less, or 20 mol% or less. Furthermore, polyamideimides containing an alicyclic tetracarboxylic dianhydride within the above range as the acid dianhydride component tend to have excellent compatibility with acrylic resins.

[0082] Examples of aromatic tetracarboxylic dianhydrides other than the specific acid dianhydrides include pyromellitic 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' 2,3,3',4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 2,2',3,3',-biphenyltetracarboxylic 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.

[0083] When an aromatic tetracarboxylic dianhydride other than the specific acid dianhydride is used in addition to the specific acid dianhydride, the amount of the aromatic tetracarboxylic dianhydride other than the specific acid dianhydride relative to the total amount of the acid dianhydride components 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 the polyamideimide in organic solvents, the amount of the aromatic tetracarboxylic dianhydride other than the specific acid dianhydride relative to the total amount of the acid dianhydride components 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.

[0084] The polyamideimide may contain, as an acid dianhydride component, a chain aliphatic tetracarboxylic dianhydride such as ethylene tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, or meso-butane-1,2,3,4-tetracarboxylic dianhydride.

[0085] The amount of the fluorine atom-containing acid dianhydride relative to the total amount of the acid dianhydride components of the polyamideimide 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. The polyamideimide may not contain a fluorine atom-containing acid dianhydride as an acid dianhydride component.

[0086] Among fluorine atom-containing acid dianhydrides, the structure in which a trifluoromethyl group is bonded to a carbon atom (-C-CF ３ ) and / or a structure in which carbon atoms are bonded to both ends of a difluoromethylene group (—C—CF ２ -C-) has low decomposition properties and there are concerns about environmental safety. ３ - or -C(CF ３ ) ２Acid dianhydrides having a structure in which - is directly bonded (for example, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride, 9-trifluoromethylxanthenetetracarboxylic dianhydride) are poorly degradable in the environment, and therefore, from the viewpoint of environmental safety of polyamideimide, it is preferable that these acid dianhydrides are substantially not contained. ３ - or -C(CF ３ ) ２ The amount of acid dianhydride to which - is directly bonded 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 may be 0.

[0087] (Polybasic Acid) As described above, by using a dicarboxylic acid and / or a tricarboxylic acid anhydride as a polybasic acid component in addition to a diamine and a tetracarboxylic acid dianhydride, a polyamideimide containing a dicarboxylic acid-derived structure represented by general formula (VIa) and / or a tricarboxylic acid anhydride-derived structure represented by general formula (VIIa) can be obtained.

[0088] 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-furandicarboxylic acid.

[0089] 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 derivatives.

[0090] From the viewpoint of the solubility of the polyamideimide, the polybasic acid is preferably an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, or trimellitic anhydride, with an aromatic dicarboxylic acid being particularly preferred. Among the 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 the alicyclic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid and bi(cyclohexyl)-4,4'-dicarboxylic acid are preferred, with 1,4-cyclohexanedicarboxylic acid being particularly preferred.

[0091] In the preparation of polyamideimide and polyamic acid as its precursor, polybasic acid derivatives such as dicarboxylic acid dichlorides, dicarboxylic acid esters, dicarboxylic acid anhydrides, and tricarboxylic acid anhydride chlorides may be used in place of the polybasic acid.

[0092] <Ratio of Amide Structures in Polyamideimide> The polyamideimide preferably contains 90 to 110 molar parts of the tetracarboxylic dianhydride-derived structure represented by general formula (IVa), the dicarboxylic acid-derived structure represented by general formula (VIa), and the tricarboxylic anhydride-derived structure represented by general formula (VIIa) relative to 100 molar parts of the diamine-derived structure represented by general formula (Va). The total of the structures of general formulas (IVa), (VIa), and (VIIa) may be 93 to 107 molar parts, 95 to 105 molar parts, 97 to 103 molar parts, or 99 to 101 molar parts relative to 100 molar parts of the structure of general formula (Va).

[0093] The ratio of the total of the structures of general formula (VIa) and general formula (VIIa) to the total of the structures of general formula (IVa), (VIa), and (VIIa) is 1 to 99 mol %. The ratio of the structures of general formula (IVa) to the structures of general formula (VIa) is approximately equal to the ratio of the imide structures of general formula (I) to the amide structures of general formula (II), and the ratio of the structures of general formula (IVa) to the structures of general formula (VIIa) is approximately equal to the ratio of the imide structures of general formula (I) to the amide-imide structures of general formula (III). The ratio of the total of the structure of general formula (VIa) and 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.

[0094] The higher the ratio of the structures of general formulae (VIa) and (VIIa), that is, the higher the ratio of the amide structure, the more improved the solubility of the polyamideimide in organic solvents may be.

[0095] The amount of polybasic acid relative to the diamine component of the polyamideimide used in this embodiment, i.e., the total ratio of the structural units of general formulae (VI) and (VII) to the structural unit 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.

[0096] <Content of specific fluorine structure in polyamideimide> As described above, the diamine component is CF ３ -O-, -(CF ２ -O) ｎ -, and -O-(CF ２ -CF ２ -O) ｎ The polyamideimide containing one or more diamines (specific diamines) having the structure selected from -C-CF ３ , -C-CF ２It is substantially free of structures such as —C— and exhibits solubility in organic solvents.

[0097] In order to reduce the environmental persistence of fluorine-containing compounds, it is preferable that the polyamideimide contains a small amount of monomers having a specific fluorine structure. The specific fluorine structure is a trifluoromethyl group (CF ３ -), excluding those containing only the components of the following structural formula (i), and a difluoromethylene group (-CF ２ -), excluding those having only the components of the following structural formula (ii): CF ３ -X (i) X-CF ２ -X' (ii)

[0098] X in formula (i) and (ii) is —OR or —NRR′, and X′ in formula (ii) is —H, —CH ３ , aromatic, —C(O)—, —OR″, —SR″, and NR″R′″. R, R′ , R″, and R′″ each independently represent —H, —CH ３ , -CH ２ -, aromatic, or -C(O)-.

[0099] 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.

[0100] <Preparation of Polyamideimide> The method for preparing polyamideimide is not particularly limited. In general, a polyamide acid as a polyamideimide precursor is prepared by reacting a diamine with a tetracarboxylic dianhydride and a polybasic acid or its derivative, and the polyamide acid is then cyclized (imidized) to obtain a polyamideimide. As described above, by adjusting the monomer composition constituting the polyamideimide, i.e., the types and ratios of the acid dianhydride, polybasic acid or its derivative, and diamine, a polyamideimide having solubility in organic solvents and transparency can be obtained.

[0101] The method for preparing polyamic acid is not particularly limited, and any known method can be used. For example, a polyamic acid solution can be obtained by dissolving the acid dianhydride and the polybasic acid or its derivative in an organic solvent in approximately equimolar amounts (molar ratio of 90:100 to 110:100) with the diamine, followed by stirring. The concentration of the polyamic acid solution is typically 5 to 35 wt %, preferably 10 to 30 wt %. A concentration within this range ensures that the polyamic acid obtained by polymerization has an appropriate molecular weight and that the polyamic acid solution has an appropriate viscosity.

[0102] In the polymerization of polyamic acid, a method of adding an acid dianhydride to a diamine is preferred to suppress ring-opening of the acid dianhydride. When adding multiple types of diamines or multiple types of acid dianhydrides, they may be added all at once or in multiple portions. The physical properties of the polyamideimide can also be controlled by adjusting the order of addition of the monomers.

[0103] The organic solvent used in the polymerization of polyamic acid is not particularly limited, as long as it does not react with the diamine and the acid dianhydride and can dissolve the polyamic acid. Examples of organic solvents include urea solvents such as methylurea and N,N-dimethylethylurea; sulfoxide or sulfone solvents such as dimethyl sulfoxide, diphenyl sulfone, and tetramethyl sulfone; amide solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), N,N'-diethylacetamide, N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, and hexamethylphosphoric triamide; alkyl halide solvents such as chloroform and methylene chloride; aromatic hydrocarbon solvents such as benzene and toluene; and ether solvents such as tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether, and p-cresol methyl ether. These solvents are typically used alone or in combination as needed. From the viewpoint of the solubility and polymerization reactivity of polyamic acid, DMAc, DMF, NMP, etc. are preferably used.

[0104] Polyamideimide is obtained by dehydration cyclization of polyamic acid. One method for preparing polyamideimide from a polyamic acid solution involves adding a dehydrating agent, an imidization catalyst, etc. to the polyamic acid solution and allowing imidization to proceed in the solution. The polyamic acid solution may be heated to accelerate the imidization process. By mixing a solution containing polyamideimide produced by imidization of polyamic acid with a poor solvent, a polyamideimide resin precipitates as a solid. Isolating the polyamideimide resin as a solid allows impurities generated during polyamic acid synthesis, residual dehydrating agents, imidization catalysts, etc., to be washed and removed with the poor solvent, preventing discoloration of the polyamideimide and increased yellowness. Furthermore, isolating the polyamideimide resin as a solid allows the use of solvents suitable for film formation, such as low-boiling point solvents, when preparing a solution for film production.

[0105] The molecular weight of the polyamideimide (weight average molecular weight in terms of polyethylene oxide measured by gel permeation 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 small, the strength of the film may be insufficient. If the molecular weight is too large, the solubility of the polyamideimide resin and its compatibility with other resins may be poor.

[0106] The polyamideimide is preferably soluble in an organic solvent. Specifically, the polyamideimide is 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, the polyamideimide is 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 a lower boiling point than amide solvents, making it easier to remove residual solvent during film production. Therefore, polyamideimides soluble in non-amide solvents are expected to improve film productivity. The polyamideimide is particularly preferably soluble in methylene chloride.

[0107] [Resin Composition] The polyamideimide of the present invention exhibits solubility in organic solvents and can exhibit compatibility with other resins. The polyamideimide of the present invention has particularly high compatibility with acrylic resins and can be used as a resin composition containing the polyamideimide and the acrylic resin.

[0108] <Acrylic Resin> Examples of acrylic resins include poly(meth)acrylic acid esters such as polymethyl methacrylate, methyl methacrylate-(meth)acrylic acid copolymers, methyl methacrylate-(meth)acrylic acid ester copolymers, methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymers, methyl (meth)acrylate-styrene copolymers, etc. The stereoregularity of the polymer is not particularly limited, and may be any of isotactic, syndiotactic, and atactic.

[0109] From the viewpoints of transparency, compatibility with polyamideimide, and mechanical strength of molded articles such as films, the acrylic resin is preferably one having methyl methacrylate as a main structural unit. The amount of methyl methacrylate relative to the total amount of monomer components in the acrylic resin is preferably 60% by weight or more, and may be 70% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or 95% by weight or more. The acrylic resin may be a methyl methacrylate homopolymer.

[0110] The acrylic resin may be one into which an imide structure or a lactone ring structure has been introduced. Such modified polymers are preferably those into which an imide structure or a lactone ring structure has been introduced into an acrylic polymer having a methyl methacrylate content within the above range. That is, in the acrylic resin modified by the introduction of an imide structure or a lactone ring structure, the total amount of methyl methacrylate and the modified structure of methyl methacrylate is preferably 60% by weight or more, and may be 70% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or 95% by weight or more. The modified polymer may be one into which an imide structure or a lactone ring structure has been introduced into a methyl methacrylate homopolymer.

[0111] Introducing an imide structure into an acrylic polymer such as methyl methacrylate tends to increase the glass transition temperature of the acrylic resin. Furthermore, since the acrylic resin contains an imide structure, its compatibility with polyamideimide may be improved. For example, even if a specific polyamideimide resin is not compatible with polymethyl methacrylate, it may be compatible with an acrylic resin having a glutarimide structure.

[0112] Acrylic resins having a glutarimide structure can be obtained by heating and melting polymethyl methacrylate resin and treating it with an imidizing agent, as described in, for example, JP 2010-261025 A. Commercially available imide-modified polymethyl methacrylates, such as "PLEXIMID TT70" and "PLEXIMID 8805" manufactured by EVONIK, can also be used.

[0113] When the acrylic resin has a glutarimide structure, the glutarimide content may be 3% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 50% by weight or more. １ The introduction rate of the glutarimide structure (imidization rate) is determined from the H-NMR spectrum, and the imidization rate is calculated by converting it into weight. For example, in the case of methyl methacrylate into which a glutarimide structure has been introduced, the O—CH ３ The area A of the peak due to protons (around 3.5 to 3.8 ppm) and the N-CH ３ The imidization rate Im=B / (A+B) can be calculated from the area B of the peak (around 3.0 to 3.3 ppm) derived from protons.

[0114] From the viewpoint of the heat resistance of the resin composition and the molded article, the glass transition temperature of the acrylic resin is preferably 100°C or higher, more preferably 110°C or higher, and may be 115°C or higher or 120°C or higher.

[0115] From the viewpoints of solubility in organic solvents, compatibility with the polyamideimide, and strength of molded articles, the weight-average molecular weight (polystyrene equivalent) of the acrylic resin is preferably 5,000 to 5,000,000, more preferably 10,000 to 2,000,000, and may be 30,000 to 1,000,000 or 50,000 to 500,000. If the molecular weight of the acrylic resin is too small, the durability of the resulting film may be reduced. If the molecular weight of the acrylic resin is too high, film formability may be poor.

[0116] From the viewpoint of the thermal stability and light stability of the resin composition and film, it is preferable that the acrylic resin has a low content of reactive functional groups such as ethylenically unsaturated groups and carboxy groups. The iodine value of the acrylic resin is preferably 10.16 g / 100 g (0.4 mmol / g) or less, more preferably 7.62 g / 100 g (0.3 mmol / g) or less, and even more preferably 5.08 g / 100 g (0.2 mmol / g) or less. The iodine value of the acrylic resin may be 2.54 g / 100 g (0.1 mmol / g) or less or 1.27 g / 100 g (0.05 mmol / g) or less. The acid value of the acrylic resin is preferably 0.4 mmol / g or less, more preferably 0.3 mmol / g or less, and even more preferably 0.2 mmol / g or less. The acid value of the acrylic resin may be 0.1 mmol / g or less, 0.05 mmol / g or less, or 0.03 mmol / g or less. A small acid value tends to increase the stability of the acrylic resin and improve its compatibility with polyamideimide.

[0117] <Preparation of Resin Composition Containing Polyamideimide and Acrylic Resin> The polyamideimide resin and acrylic resin are mixed to prepare a resin composition. The polyamideimide resin and acrylic resin can be compatible at any ratio, so the ratio of polyamideimide resin to acrylic resin in the resin composition is not particularly limited. The mixing ratio (weight ratio) of polyamideimide resin to acrylic resin may be 98:2 to 2:98, 95:5 to 10:90, or 90:10 to 15:85. The higher the ratio of polyamideimide resin, the higher the elastic modulus of the film and the greater the mechanical strength. The higher the ratio of acrylic resin, the less coloring there is and the greater the transparency of the film.

[0118] In order to fully exert the effect of improving transparency by mixing polyamideimide and acrylic resin, the ratio of the acrylic resin to the total of polyamideimide and acrylic resin 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.

[0119] Polyamideimides are polymers with a special molecular structure, and generally have low solubility in organic solvents and are not compatible with other polymers. However, as described above, polyamideimides containing specific diamine components and acid dianhydride components exhibit high solubility in organic solvents and are compatible with acrylic resins.

[0120] A resin composition containing a polyamideimide resin and an acrylic resin preferably has a single glass transition temperature in differential scanning calorimetry (DSC) and / or dynamic mechanical analysis (DMA). When the resin composition has a single glass transition temperature, the polyamideimide resin and the acrylic resin can be considered to be completely compatible with each other. A film containing a polyamideimide resin and an acrylic resin also preferably has a single glass transition temperature.

[0121] The resin composition may be a simple mixture of a polyamideimide resin precipitated as a solid content and an acrylic resin, or a mixture of polyamideimide and an acrylic resin. Furthermore, when a polyamideimide solution is mixed with a poor solvent to precipitate a polyamideimide resin, an acrylic resin may be mixed with the solution, and the resin composition obtained by mixing the polyamideimide and the acrylic resin may be precipitated as a solid (powder).

[0122] The resin composition may be a mixed solution containing a polyamideimide resin and an acrylic resin. The method for mixing the resins is not particularly limited, and the resins may be mixed in a solid state or in a liquid state to form a mixed solution. A polyamideimide resin solution and an acrylic resin solution may be prepared separately, and then the two may be mixed to prepare a mixed solution of the polyamideimide resin and the acrylic resin.

[0123] The solvent for the solution containing the polyamideimide resin and the acrylic resin is not particularly limited as long as it can dissolve both the polyamideimide resin and the acrylic resin. Examples of the solvent 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 halide solvents such as chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chlorobenzene, dichlorobenzene, and methylene chloride.

[0124] From the viewpoints of the solubility of polyamideimide and the compatibility of polyamideimide with acrylic resin in solution, amide solvents are preferred. On the other hand, from the viewpoint of the removability of the solvent when producing a molded product such as a film, low-boiling non-amide solvents are preferred, and ketone solvents and alkyl halide solvents are preferred because they have excellent solubility in both polyamideimide and acrylic resin and have low boiling points, making it easy to remove the remaining solvent when producing a film.

[0125] The resin composition may contain organic or inorganic low molecular weight compounds, polymeric compounds (e.g., epoxy resins), etc. The resin composition may contain flame retardants, ultraviolet absorbers, crosslinking agents, dyes, pigments, surfactants, leveling agents, plasticizers, fine particles, sensitizers, etc. The fine particles 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 includes carbon fiber, glass fiber, aramid fiber, etc.

[0126] Resin compositions containing polyamideimide and acrylic resins tend to have lower melt viscosities than polyamideimide alone, and are excellent in moldability in injection molding, transfer molding, press molding, melt extrusion molding, and the like. Furthermore, solutions of resin compositions containing polyamideimide and acrylic resins tend to have lower solution viscosities than solutions of polyamideimide alone with the same solids concentration. Therefore, they are easy to handle, such as during solution transportation, and have high coatability, which is advantageous in reducing unevenness in film thickness.

[0127] A molded article molded from a solution of a resin composition containing polyamideimide and an acrylic resin has a lower glass transition temperature than a molded article molded from a solution of the same polyamideimide alone, and therefore tends to have a lower amount of residual solvent in the molded article when treated under the same heating conditions. In particular, when an amide-based high-boiling point solvent is used, high-temperature heating at 250°C or higher or 300°C or higher may be required to remove the solvent, which may result in a decrease in the transparency of the resulting molded article. However, when a resin composition containing polyamideimide and an acrylic resin is used, the amount of residual solvent can be reduced by heating for a shorter period of time, thereby suppressing coloration during heating and making it easier to obtain a molded article with high transparency.

[0128] [Molded Articles and Films] The above-mentioned polyamideimides and resin compositions containing polyamideimides and acrylic resins can be used to form various molded articles. Molding methods include melt methods such as injection molding, transfer molding, press molding, blow molding, inflation molding, calendar molding, and melt extrusion molding.

[0129] In one embodiment, the molded article is a film. The film may be molded 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 solution containing the polyamideimide is applied to a support, and the solvent is then dried and removed to obtain a film. Since the polyamideimide and the acrylic resin are compatible in solution, a highly transparent film can be produced by the solution method by using the polyamideimide and the acrylic resin in combination.

[0130] The resin solution can be applied to a support by a known method using a bar coater, a comma coater, or the like. The support may be a glass substrate, a metal substrate such as SUS, a metal drum, a metal belt, a plastic film, or the like. From the viewpoint of improving productivity, it is preferable to use an endless support such as a metal drum or a metal belt, or a long plastic film as the support and produce the film by a roll-to-roll method. When using a plastic film as the support, it is sufficient to appropriately select a material that is insoluble in the solvent of the film-forming dope.

[0131] It is preferable to heat the film when drying the solvent. The heating temperature is not particularly limited as long as it can remove the solvent and can suppress coloration of the resulting film, and is appropriately set between room temperature and about 250°C, with 50°C to 220°C being preferred. The heating temperature may be increased in stages. In order to increase the efficiency of solvent removal, the resin film may be peeled off from the support and dried after drying has progressed to a certain extent. Heating may be performed under reduced pressure to promote solvent removal.

[0132] The film may be stretched in one or more directions for the purpose of improving the mechanical strength, etc. When the film is stretched, the polymer chains are oriented in the stretching direction, which tends to improve the strength of the film in the in-plane direction and suppress the occurrence of breakage or cracks in the film.

[0133] Films used as cover films or substrate materials for foldable displays are repeatedly folded along the folding axis at the same location, and therefore are required to have high mechanical strength in a direction perpendicular to the folding axis. Therefore, by arranging the film so that the stretching direction is perpendicular to the folding axis, even when the film is repeatedly folded, breakage or cracking of the film at the folding location is unlikely to occur, and a device with high bending resistance can be provided.

[0134] The conditions for stretching the film are not particularly limited. For example, the stretching temperature is the glass transition temperature of the film ±40°C. The stretching temperature may be about 120 to 300°C, 150 to 250°C, or 180 to 230°C.

[0135] The stretching ratio is about 1 to 200%, and may be 5 to 150%, 10 to 120%, or 20 to 100%. The stretching ratio (%) is 100×(L １ -L ０ ) / L ０ and L ０ is the length in the stretching direction of the film before stretching (original length), and L １ is the length of the stretched film in the stretching direction. The larger the stretching ratio, the larger the tensile modulus in the stretching direction tends to be. In particular, in a compatible system of polyamideimide and acrylic resin, the tensile modulus in the stretching direction tends to be larger, and as a result, the flex resistance tends to be improved. The higher the ratio of methyl methacrylate in the monomer components of the acrylic resin, the more pronounced the tendency for the tensile modulus in the stretching direction to increase. If the stretching ratio is excessively large, the mechanical strength in the direction perpendicular to the stretching direction tends to decrease, and the handleability of the film may be reduced.

[0136] The film may be biaxially stretched to increase the strength in any in-plane direction. The 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 perpendicular direction may be the same or different. When a difference in stretching ratio is made, the mechanical strength in the direction with the larger stretching ratio tends to be relatively larger. When a biaxially stretched film with anisotropic stretching ratio is used in a foldable device, it is preferable to arrange it so that the direction with the larger stretching ratio is perpendicular to the folding axis.

[0137] The thickness of the film is not particularly limited and may be appropriately set depending on the application. The film thickness is, for example, 5 to 300 μm. From the viewpoint of obtaining a film that is both self-supporting and flexible and has high transparency, the film thickness is preferably 20 μm to 200 μm, and may be 30 μm to 150 μm, 40 μm to 100 μm, or 50 μm to 80 μm. The thickness of a film used as a cover film for a display is preferably 10 μm or more. When the film is stretched, the thickness after stretching is preferably within the above range.

[0138] The haze of the film is not particularly limited, but 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, polyamideimide and acrylic resin are compatible, so a film containing polyamideimide and acrylic resin has low haze and excellent transparency, similar to a film made of polyamideimide alone.

[0139] The total light transmittance of the film is not particularly limited, but is preferably 87% or more, more preferably 88% or more, and may be 89% or more or 90% or more. A film containing polyamideimide and an acrylic resin has a higher total light transmittance than a film made of polyamideimide alone, and can exhibit a total light transmittance of 90% or more.

[0140] The yellowness index (YI) of the film is not particularly limited, but 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. A film containing polyamideimide and an acrylic resin has a lower YI than a film containing polyamideimide alone, and even if the YI of a film containing polyamideimide alone exceeds 10, it is possible to reduce the YI by adopting a mixed system with an acrylic resin. A film containing polyamideimide and an acrylic resin can achieve a low YI of 1.0 or less.

[0141] From the viewpoint of strength, the tensile modulus of the film is preferably 2.5 GPa or more, more preferably 3.0 GPa or more, more preferably 3.5 GPa or more, and may be 4.0 GPa or more. The pencil hardness of the film is preferably 6B or more, more preferably 4B or more, even more preferably B or more, and may be H or more, 2H or more, or 3H or more. In a compatible system of polyamideimide and acrylic resin, even if the ratio of acrylic resin is increased, the pencil hardness tends not to decrease. Therefore, a film with little coloration and excellent transparency can be provided without significantly decreasing the excellent mechanical strength specific to polyamideimide.

[0142] The polyamideimide-containing film of the present invention is suitable for use as a display material due to its low coloration and high transparency. In particular, films with high mechanical strength can be applied to surface components such as display cover windows. Furthermore, since the polyamideimide is substantially free of specific fluorine structures, it is highly degradable and environmentally safe. When used in practice, the film of the present invention may be provided with an antistatic layer, an easy-adhesion layer, a hard coat layer, an antireflection layer, etc., on its surface.

[0143] The following examples will be used to further explain the present invention, but the present invention is not limited to these examples.

[0144] [Preparation of Polyamide-imide Resin] N,N-dimethylacetamide (DMAc) was placed in a separable flask and stirred under a nitrogen atmosphere. Diamine, tetracarboxylic dianhydride, and polybasic acid derivative were added in the ratios shown in Tables 1 and 2, and the mixture was stirred under a nitrogen atmosphere for 5 to 10 hours to react, yielding a polyamic acid solution with a solids concentration of 10 wt %.

[0145] To 100 g of the polyamic acid solution, 5.5 g of pyridine was added as an imidization catalyst, and after complete dispersion, 8 g of acetic anhydride was added, and the mixture was stirred for 3 hours at 90° C. to carry out imidization. In Comparative Examples 1 to 4 in Table 2, the solubility of polyamideimide in DMAc was low, and gelation or precipitation occurred during the imidization process, so the subsequent operations were not carried out.

[0146] After the imidization, the solution was cooled to room temperature, and then 100 g of 2-propyl alcohol (hereinafter referred to as IPA) was added at a rate of 2 to 3 drops per second while stirring, causing polyamideimide to precipitate. 150 g of IPA was then added, and after stirring for approximately 30 minutes, the solution was subjected to suction filtration using a Kiriyama funnel. The resulting solid was washed with IPA and then dried for 12 hours in a vacuum oven set at 120°C, yielding a polyamideimide resin.

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[0148] [Film Evaluation] <Haze and Total Light Transmittance> The film was cut into a 3 cm square, and the haze and total light transmittance (TT) were measured using a haze meter "HZ-V3" manufactured by Suga Test Instruments in accordance with JIS K7136 and JIS K7361-1.

[0149] <Total Light Transmittance> The film was cut into a 3 cm square, and the total light transmittance (TT) was measured using a haze meter "HZ-V3" manufactured by Suga Test Instruments in accordance with JIS K7136 and JIS K7361-1.

[0150] <Yellowness Index> The film was cut into a 3 cm square, and the yellowness index (YI) was measured according to JIS K7373 using a spectrophotometer "SC-P" manufactured by Suga Test Instruments.

[0151] <Tensile modulus> The film was cut into a 10 mm wide strip and allowed to stand at 23°C / 55% RH for 1 day to condition the humidity. The tensile modulus was then measured using an AUTOGRAPH AGS-X manufactured by Shimadzu Corporation under the following conditions: Grip distance: 100 mm, Pulling speed: 20.0 mm / min, Measurement temperature: 23°C.

[0152] [Evaluation Results] The compositions of the polyamideimides of the Examples and Comparative Examples, and the evaluation results of the polyamideimide films of the Examples, are shown in Tables 1 and 2. In Comparative Examples 1 to 4, solvent-soluble polyamideimides were not obtained, so Table 2 shows only the compositions.

[0153] In Tables 1 and 2, and Table 3 described later, the composition of the polyamideimide (diamine, tetracarboxylic dianhydride, and polybasic acid derivative) is shown as a molar ratio where the sum of the total amount of tetracarboxylic dianhydride and the total amount of polybasic acid derivative is 100 parts by mole, and the compounds are described by the following abbreviations. <Diamines> TFMOB: 2,2'-bis(trifluoromethoxy)benzidine 2,2-Bz: 2,2'-dimethylbenzidine 3,3'-DDS: 3,3'-diaminodiphenylsulfone BAFL: 9,9-bis(4-aminophenyl)fluorene m-Tol: 4,4'-diamino-2,2'-dimethylbiphenyl <Acid dianhydrides> BPADA: 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride s-ODPA: 4,4'-oxydiphthalic anhydride BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride BPF-PA: 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride TBIS. MPN: 5,5'-(9H-fluoren-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylate] TBIS.RXN: 5,5'-spiro[9H-fluorene-9,9'-[9H]xanthene]-3',6'-diylbis(1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylate) TAHMBP: bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-2,2',3,3',5,5'-hexamethylbiphenyl-4,4'diyl CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride PMDA: pyromellitic dianhydride BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride <Polybasic acid derivatives> TPC: Terephthalic acid dichloride TMAC: Trimellitic anhydride chloride

[0154]

[0155]

[0156] The polyamideimides of Examples 1 to 22, which contained a specific diamine as the diamine component, were soluble in organic solvents and could be used to prepare transparent films.On the other hand, the polyamideimides of Comparative Examples 1 to 4, which did not contain a specific diamine, were insoluble in organic solvents.

[0157] These results show that by using a specific diamine that does not contain a specific fluorine structure as the diamine component, a polyamideimide that is highly environmentally safe and has excellent solubility in organic solvents and transparency can be obtained.

[0158] [Preparation of resin composition of polyamideimide and acrylic resin] The polyamideimide of Example 1 and glutarimide-modified acrylic resin (prepared according to "Acrylic Resin Production Example 3" of JP 2018-70710 A; glutarimide content 33 wt%, glass transition temperature 131 ° C., hereinafter "HGI") were dissolved in DMF at a 50:50 weight ratio to prepare a solution with a solids concentration of 10 wt%. The polyamideimide of Examples 3, 9 to 14, 16, 18, 21, and 22 and a commercially available polymethyl methacrylate resin ("Parapet HM1000" manufactured by Kuraray, glass transition temperature: 120 ° C., acid value: 0.0 mmol / g, hereinafter "HM") were dissolved in DMF at a 50:50 weight ratio to prepare a solution with a solids concentration of 10 wt%. In all examples, the mixed resin solution was transparent, indicating compatibility between the polyamideimide and the acrylic resin.

[0159] [Film Preparation and Evaluation] The mixed resin solution was applied to a non-alkali glass plate and dried by heating in the air at 60°C for 15 minutes, 90°C for 15 minutes, 120°C for 15 minutes, 150°C for 15 minutes, 180°C for 15 minutes, and 200°C for 15 minutes to prepare a film having a thickness of approximately 50 μm.

[0160] The resulting film was evaluated in the same manner as the polyamideimide film described above. The polyamideimide composition, the type of acrylic resin, and the evaluation results of the film are shown in Table 3.

[0161]

[0162] The films of Examples 101, 103, 109-114, 116, 118, 121, and 122, which are mixed resin films of polyamideimide and acrylic resin, have mechanical strength (tensile modulus) equivalent to that of the films of Examples 1, 3, 9-14, 16, 18, 21, and 22, which are films of polyamideimide alone, and tend to have improved transparency compared to films of polyamideimide alone. For example, the polyamideimide film of Example 12 had a YI of over 10, while the film of Example 112 had a YI reduced to 4.2 and a total light transmittance of over 90%, significantly improving transparency. In the other examples, it can be seen that the mixed resin films of polyamideimide and acrylic resin have a smaller YI, a higher total light transmittance, and excellent transparency compared to films of polyamideimide alone.

[0163] These results show that polyamideimides using specific diamines as the diamine component are soluble in organic solvents, have excellent compatibility with acrylic resins, and can give highly transparent films.

Claims

1. A polyamide-imide having a diamine component, a tetracarboxylic dianhydride component, and a polybasic acid component, wherein the diamine component is CF ３ -O-, -(CF ２ -O) ｎ -, and -O-(CF ２ -CF ２ -O) ｎ - (n is an integer of 1 to 20), 2. The polyamideimide according to claim 1, wherein the fluorine atom-containing diamine is 2,2'-bis(trifluoromethoxy)benzidine, 3,3'-bis(trifluoromethoxy)benzidine, or 2,3'-bis(trifluoromethoxy)benzidine.

3. The polyamideimide according to claim 1, comprising, as a tetracarboxylic dianhydride component, one or more tetracarboxylic dianhydrides selected from the group consisting of tetracarboxylic dianhydrides having an ether bond, tetracarboxylic dianhydrides having a fluorene structure, tetracarboxylic dianhydrides having a xanthene structure, and bis(trimellitic anhydride) esters.

4. The one or more tetracarboxylic dianhydrides selected from the group consisting of tetracarboxylic dianhydrides having an ether bond, tetracarboxylic dianhydrides having a fluorene structure, tetracarboxylic dianhydrides having a xanthene structure, and bis(trimellitic anhydride) esters are selected from the group consisting of 4,4'-(4,4'-isopropylidenediphenoxy)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, 5,5'-(9H-fluoren-9-ylidenebis(2-methyl-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5-isobenzofuran-2-yl ... furan 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.

5. The polyamideimide according to claim 3, further comprising, as the tetracarboxylic dianhydride component, one or more tetracarboxylic dianhydrides selected from the group consisting of 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, and 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride.

6. The polyamideimide according to claim 1, which contains an alicyclic tetracarboxylic dianhydride as the tetracarboxylic dianhydride component, and the amount of the alicyclic tetracarboxylic dianhydride relative to the total amount of the tetracarboxylic dianhydride component is 1 to 80 mol %.

7. The polyamideimide according to claim 6, wherein the alicyclic tetracarboxylic dianhydride is one or more selected from the group consisting of 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, and 1,1'-bicyclohexane-3,3',4,4'tetracarboxylic acid-3,4:3',4'-dianhydride.

8. The amount of CF on the carbon atom of the aromatic ring relative to the total amount of the diamine component ３ - or -C(CF ３ ) ２ The amount of the diamine having a structure in which - is directly bonded is less than 0.5 mol %, and the amount of the diamine having a structure in which - is directly bonded to a carbon atom of an aromatic ring is less than 0.5 mol % based on the total amount of the tetracarboxylic dianhydride component. ３ - or -C(CF ３ ) ２ The polyamideimide according to claim 1, wherein the amount of the tetracarboxylic dianhydride having a structure in which - is directly bonded is less than 0.5 mol %.

9. The polyamideimide according to claim 1, which is soluble in dimethylformamide at 23°C.

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

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

12. A resin composition comprising the polyamideimide according to any one of claims 1 to 9 and an acrylic resin.

13. The resin composition according to claim 12, comprising said polyamideimide and said acrylic resin in a weight ratio ranging from 98:2 to 2:

98.

14. A molded article comprising the resin composition according to claim 12.

15. A film comprising the resin composition according to claim 12.

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