KR20180136582A - Thermoplastic polyimide - Google Patents

Abstract

An object of the present invention is to provide a thermoplastic polyimide excellent in transparency, heat resistance, melt heat stability, solvent nonvolatility, and the like, and a thermoplastic polyimide formed article obtained by melt extrusion molding the thermoplastic polyimide. The present invention relates to a thermoplastic polyimide having an alicyclic structure and having a 95% or more sealing ratio of terminal amino groups and an imidization rate of 95.8% or more.

Description

[0001] THERMOPLASTIC POLYIMIDE [0002]

The present invention relates to a thermoplastic polyimide excellent in transparency, heat resistance, melt thermal stability, solvent nonvolatility and the like, and a thermoplastic polyimide molded article obtained by melt extrusion molding the thermoplastic polyimide.

Since polyimide has excellent properties in terms of heat resistance, mechanical properties, chemical resistance and electrical characteristics, it is widely used in the fields of automobiles, aerospace industry, electricity, electronics, and batteries.

Polyimide is generally a thermosetting resin having excellent heat resistance while having no clear glass transition temperature. When it is used as a molding material, a special technique such as sintering molding must be used. In order to obtain a workpiece having a complicated shape by the sintering molding method, complicated and troublesome machining steps are required, such as cutting out a desired shape from a polyimide block by using a cutting machine such as an NC lathe, . Further, the polyimide generally has a total aromatic skeleton, so that the molded article is colored. Therefore, there is also a problem that it can not be used in applications requiring transparency.

Thus, in order to improve molding processability, thermoplastic polyimide capable of melt-molding at a certain temperature or higher has been developed, like a general-purpose thermoplastic resin. For example, Patent Document 1 discloses a thermoplastic polyimide having a skeleton of 3,3 ', 4,4'-diphenylether tetracarboxylic acid as a basic skeleton. Patent Document 1 discloses a method of imidizing a polyamic acid resin solution, which is a polyimide precursor, in a solution as a polyimide production method.

On the other hand, in order to improve the transparency, a transparent polyimide using at least one of an alicyclic tetracarboxylic acid dianhydride and an aliphatic diamine has been developed. For example, Patent Document 2 discloses a transparent polyimide using a 3,4,3 ', 4'-dicyclohexyltetracarboxylic acid dianhydride skeleton. In addition, as a method for producing the transparent polyimide, Method and a method of obtaining a transparent polyimide molded article by heat imidization. Patent Document 3 describes a method for obtaining a polyimide by imidizing a polyamic acid resin having an aliphatic tetracarboxylic acid skeleton in a solution.

Japanese Unexamined Patent Publication No. 4-331231 Japanese Patent Application Laid-Open No. 8-104750 Japanese Laid-Open Patent Publication No. 2005-15629 Japanese Patent Application Laid-Open No. 2008-297360

Since the polyimide described in Patent Document 1 has a high glass transition temperature and further has crystallinity, it is difficult to obtain a molten state at the upper limit of the melting temperature in a typical industrial process, Cast method. In addition, since the polyimide has a large number of aromatic skeletons, there is a problem in terms of color tone and transparency.

The technique disclosed in Patent Document 2 is a technique of forming a solution of polyamic acid by a solvent casting method (solution casting method) to obtain a polyimide film, but it is not possible to produce only a film on a thin film, , It takes time to dry the solvent, and thus the productivity is poor. In addition, since the polyamic acid solution easily hydrolyzes by moisture in the air, there is a problem that the molecular weight is changed during storage and the viscosity is lowered. Further, according to the studies of the present inventors, there is a problem that the imidization rate of the polyimide is insufficient and the primary amino group remains at the terminal thereof, and thus the melt thermal stability is insufficient, and that this causes coloration I got it.

On the other hand, Patent Document 3 discloses a solvent casting method in which polyimide is mixed with a solvent in a solution state. However, as in Patent Document 2, only a thin film can be produced, There is a problem in that it takes time to dry the polyimide and that the cost is increased thereby, and further, there is a problem that the primary amino group remains at the terminal of the polyimide, which causes coloring. Also in the method of obtaining a polyimide molded product by melt-molding a polyimide solution mixed with a solvent, since a solvent is contained in the polyimide, significant foaming is observed at the time of melting, and problems such as generation of a flammable gas , This viscosity needs to be improved.

Patent Document 4 discloses that polyimide having excellent solubility in an organic solvent is obtained by controlling the steric structure of polyimide having an alicyclic structure. However, Patent Document 4 also discloses a molding method using a conventional solvent casting method, and there are problems as exemplified in Patent Documents 2 and 3 above.

The polyimide having an alicyclic structure as described in Patent Documents 2 to 4 is thermoplastic and excellent in transparency and heat resistance, and is expected to be used as a polyimide film for use in flexible devices and organic EL However, conventional methods such as the solvent casting method used for forming polyimide have problems such as insufficient productivity, difficulty in forming a polyimide film only as a thin film, and difficulty in forming a thick film, I found out.

The present inventors have solved the problems in the solvent casting method as described above by the melt extrusion molding method. On the other hand, the polyimide having an alicyclic structure as described in Patent Documents 2 to 4, It has been found that it does not have such a melt heat stability as to be able to be applied.

The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to provide a thermoplastic polyimide excellent in transparency, heat resistance, melt thermal stability, solvent nonvolatility and the like and a thermoplastic polyimide formed article obtained by melt extrusion molding the thermoplastic polyimide.

The invention has been made in view of the above problems. As a result of intensive studies by the present inventors, it has been concluded that the problems of melt heat stability of the polyimide described in Patent Documents 2 to 4 are due to insufficient imidization rate of polyimide and residual terminal amino groups It came. Since the aromatic polyimide described in Patent Document 1 has a rigid structure, the amic acid structure hardly remains and the imidization proceeds easily. On the other hand, since Patent Documents 2 to 4 have an alicyclic structure, And the amic acid structure is likely to remain.

As described above, the inventors of the present invention have found that polyimide having an alicyclic structure can be obtained by increasing the imidization ratio and increasing the sealing ratio of the amino group, so that the polyimide having excellent melt heat stability is applicable to melt extrusion molding, The present invention has been completed.

That is, the gist of the present invention is in the following [1] to [9].

[1] A thermoplastic polyimide having an alicyclic structure, a terminal amino group having a sealing ratio of 95.0% or more, and an imidization rate of 95.8% or more.

[2] The thermoplastic polyimide according to [1], wherein the weight average molecular weight (Mw) is 10,000 to 500,000.

[3] The thermoplastic polyimide according to [1] or [2], wherein the alicyclic structure is a cyclohexane ring structure.

[4] The thermoplastic polyimide according to any one of [1] to [3], wherein the alicyclic structure is adjacent to the imide ring structure by sharing two carbon atoms.

[5] The thermoplastic polyimide according to any one of [1] to [4], wherein the alicyclic structure has at least one of a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2)

[Chemical Formula 1]

[6] A thermoplastic polyimide according to any one of [1] to [5], further having a structural unit represented by the following formula (3).

(2)

(3), R ¹ to R ⁸ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms or a hydroxyl group, X is a direct bond, A sulfur atom, an alkylene group having 1 to 4 carbon atoms, a sulfonyl group, a sulfonyl group, a sulfide group, a carbonyl group, an amide group, an ester group or a secondary amino group and n is an integer of 0 to 4)

[7] The thermoplastic polyimide according to any one of [1] to [6], wherein the polymer has a complex shear viscosity (η ^* ) at 310 ° C. of 1 × 10 ² to 5 × 10 ⁵ Pa · s.

[8] The thermoplastic polyimide according to any one of [1] to [7], wherein a change rate of a complex shear viscosity before and after elapse of 60 minutes at 310 ° C. is 300% or less.

[9] A thermoplastic polyimide formed article obtained by melt extrusion molding the thermoplastic polyimide described in any one of [1] to [8].

According to the present invention, there is provided a thermoplastic polyimide excellent in transparency, heat resistance, solvent nonvolatility and the like, and particularly excellent in melt heat stability such that melt extrusion molding is possible. According to the present invention, there is also provided a thermoplastic polyimide molding obtained by melt extrusion molding of the thermoplastic polyimide.

[Thermoplastic polyimide]

The thermoplastic polyimide of the present invention has an alicyclic structure and has a 95% or more sealing ratio of the terminal amino group and an imidization rate of 95.8% or more.

The thermoplastic polyimide of the present invention exerts an effect that the melt thermal stability is remarkably excellent as compared with the conventional polyimide having an alicyclic structure as described in Patent Documents 2 to 4. [ According to a detailed examination by the present inventors, it has been found that the imidization is not sufficiently progressed in the Patent Documents 2 to 4, the amic acid remains, and the sealing ratio of the terminal amino group is insufficient. In such a thermoplastic polyimide, a reaction occurs between an amic acid and a terminal amino group in the polyimide molecule when heated to 300 ° C or higher, and a reaction between the amic acid between the polyimide molecules occurs, . ≪ / RTI >

[Chemical structure]

The thermoplastic polyimide of the present invention has an alicyclic structure. The alicyclic structure is not particularly limited, but is usually an alicyclic structure having 5 to 12 carbon atoms, preferably an alicyclic structure having 6 to 10 carbon atoms, and particularly preferably a cyclohexane ring structure. The thermoplastic polyimide of the present invention has an alicyclic structure and thus has a thermoplasticity and a high transparency. The "alicyclic structure" in the present invention is also used to include those having a hetero atom in the ring structure, and it is preferably an alicyclic structure having no hetero atom in the ring structure.

The thermoplastic polyimide of the present invention can be obtained from a carboxylic acid dianhydride (hereinafter referred to as " acid dianhydride ") diamine compound as a raw material, as will be described later. The alicyclic structure in the thermoplastic polyimide of the present invention may be derived from an acid dianhydride or may be derived from a diamine compound, preferably an alicyclic structure derived from an acid dianhydride.

The thermoplastic polyimide of the present invention is preferably one in which the alicyclic structure is adjacent to the imide ring structure by sharing two carbon atoms. If the alicyclic structure is adjacent to the imide ring structure by sharing two carbon atoms, it is preferable that the structure is compatible with the transparency based on the alicyclic structure and the heat resistance and chemical stability derived from the imide ring structure. Preferable examples of the adjacent structure in which the alicyclic structure shares two carbon atoms with the imide ring structure include, for example, a structure in which the alicyclic structure is a cyclohexane ring structure (structure represented by the following formula (4)).

(3)

The aliphatic structure in the thermoplastic polyimide of the present invention preferably has at least one of a structural unit represented by the structural unit represented by the following formula (1) and a structural unit represented by the following formula (2). When at least one of the structural unit represented by the formula (1) and the structural unit represented by the formula (2) is contained, transparency and toughness are particularly excellent, which is preferable. The structural unit represented by the formula (1) can be usually derived from an acid dianhydride represented by the following formula (5), and the structural unit represented by the formula (2) May be introduced from an acid anhydride represented by the following formula.

[Chemical Formula 4]

In the thermoplastic polyimide of the present invention, the sealing ratio of the terminal amino group is not less than 95.0% and the imidization rate is not less than 95.8%, whereby excellent fusion thermal stability can be obtained so as to enable melt extrusion molding.

The thermoplastic polyimide of the present invention preferably has a sealing ratio of the terminal amino group of 96.0% or more, more preferably 97.0% or more, and still more preferably 98.0% or more, from the viewpoint of better melting heat stability . The upper limit of the sealing ratio of the terminal amino group of the thermoplastic polyimide is not limited, and is usually 100%.

As described later, the sealing ratio of the terminal amino group is determined by the ratio of the amount of the acid dianhydride to the diamine compound used, the amount of the end sealant used in the end sealing reaction and the kind thereof, the catalyst in the chemical imidization reaction step, And the amount of these used. The sealing ratio of the terminal amino group can be determined by ¹ H-NMR measurement. Specific examples thereof are shown in Examples. In the present invention, the term " sealing of the terminal amino group " means not only the hydrogen atom bonded to the terminal primary amino group is substituted by the terminal sealing agent, but also the terminal amino group in the chemical imidization reaction step, Reaction of a condensation agent, and the like, including unintended end sealing.

The thermoplastic polyimide of the present invention preferably has an imidization rate of 96.0% or more, more preferably 96.5% or more, still more preferably 97.0% or more from the viewpoint of better melt heat stability , Particularly preferably not less than 98.0%. The upper limit of the imidization rate of the thermoplastic polyimide is not limited, and is usually 100%.

In the present invention, the imidization rate can be controlled by the conditions of the end sealing step and the chemical imidization reaction step, as described later. In order to increase the imidization rate without going through the end sealing step, the dehydration condensing agent used in the chemical imidization reaction step is used in a relatively large amount as described later, whereby the imidization ratio can be increased. The imidization rate of the thermoplastic polyimide of the present invention is determined by ¹ H-NMR measurement, and specific examples thereof are shown in the examples. Further, when the imidization rate can not be obtained by ¹ H-NMR measurement, it can be obtained by NMR measurement based on atoms other than hydrogen atoms.

The thermoplastic polyimide of the present invention preferably has a structural unit represented by the following formula (3). Having a structural unit represented by the formula (3) is preferable because heat resistance and toughness tend to be better.

[Chemical Formula 5]

In formula (3), R ¹ to R ⁸ may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a hydroxyl group. Among them, a hydrogen atom or a methyl group is preferable.

In the formula (3), X is a direct bond, an oxygen atom, a sulfur atom, an alkylene group having 1 to 4 carbon atoms, a sulfonyl group, a sulfinyl group, a sulfide group, a carbonyl group, an amide group, an ester group or a secondary amino group. Among them, a direct bond, an oxygen atom, a sulfur atom, an alkylene group having 1 to 4 carbon atoms, a sulfonyl group or an amide group is preferable, and an oxygen atom is particularly preferable.

In the formula (3), n is an integer of 0 to 4. n is preferably an integer of 1 to 4.

In the structural unit represented by the formula (3) in one whole thermoplastic polyimide, R ¹ to R ⁸ , X and n may not necessarily be the same. In particular, when n is an integer of 2 or more, X may be a different structure.

Among the structural units represented by the formula (3), those represented by any one of the structural units represented by the following formulas (3-1) to (3-6) are preferable. Further, the structural units may be contained in only one type of thermoplastic polyimide in one molecule, or may be contained in combination of a plurality of types.

[Chemical Formula 6]

The thermoplastic polyimide of the present invention may have other structural units in addition to structural units represented by the above-mentioned formulas (1) to (3). The other structural units can be introduced based on raw materials other than the compounds represented by the formulas (5) to (7) listed in the production method described later.

[Properties]

The thermoplastic polyimide of the present invention preferably has a weight average molecular weight (Mw) of 10,000 or more, more preferably 30,000 or more, particularly preferably 45,000 or more, and preferably 500,000 or less, Preferably 300,000 or less, more preferably 150,000 or less, and particularly preferably 130,000 or less. When the weight average molecular weight of the polyimide is not lower than the lower limit value, it is preferable from the viewpoint of toughness when the polyimide is formed into a molded product. When the weight average molecular weight is lower than the upper limit, it is preferable from the viewpoint of fluidity and moldability. The weight average molecular weight of the thermoplastic polyimide of the present invention can be measured by gel permeation chromatography (GPC). More detailed conditions of the GPC measurement will be described later in Examples.

The thermoplastic polyimide of the present invention preferably has a complex shear viscosity (η ^* ) at 310 ° C. of 1 × 10 ² Pa · s or more, more preferably 1 × 10 ³ Pa · s or more, and more preferably 5 × 10 ⁵ Pa s or less, and more preferably 1 x 10 < ⁵ > Pa s or less. It is preferable that the complex shear viscosity is in the above-mentioned range because the fluidity becomes appropriate for molding. The complex shear viscosity can be controlled by the molecular weight, the molecular composition, and the like. In general, when the molecular weight is large, the complex shear viscosity becomes large. The complex shear viscosity can be measured by the method described in the following Examples.

Further, the thermoplastic polyimide of the present invention is excellent in melt heat stability. Specifically, the thermoplastic polyimide of the present invention has a complex shear viscosity (? ^* ₀ ) immediately after melting at 310 占 폚 for 60 minutes and a complex shear viscosity (? ^* ₆₀ ) after 60 minutes The rate of change in viscosity is preferably 300% or less, more preferably 200% or less, and even more preferably 100% or less. The rate of change of the complex shear viscosity shows the flow stability at the time of melting. Therefore, it is preferable that the rate of change of the complex shear viscosity is not more than the above-mentioned upper limit value from the viewpoint of melt stability and control of the film thickness when the film is formed easily. The lower limit of the rate of change of the complex shear viscosity is usually zero. The rate of change of the complex shear viscosity tends to decrease as the sealing ratio of the terminal amino group increases. In the present invention, the rate of change of the complex shear viscosity is defined by the following formula, and can be measured by the method described in the following Examples.

(Rate of change in complex shear viscosity) = [(? ^* ₆₀ -? ^* ₀ ) /? ^* ₀ ] 100

The thermoplastic polyimide of the present invention preferably has a glass transition temperature (Tg) of 150 占 폚 or higher, more preferably 200 占 폚 or higher, and particularly preferably 250 占 폚 or higher by a DMS method (dynamic thermomechanical measuring apparatus) to be. From the viewpoint of heat resistance, it is preferable that the glass transition temperature is not less than the lower limit. On the other hand, the upper limit of the glass transition temperature is not particularly limited, but is usually 350 DEG C or lower. The glass transition temperature according to the DMS method can be measured by the method described in the following Examples.

The thermoplastic polyimide of the present invention preferably has a thermal expansion coefficient of 100 ppm / 占 폚 or lower, more preferably 70 ppm / 占 폚 or lower, in the range of 100-200 占 폚. It is preferable that the thermal expansion coefficient is not more than the upper limit value because a polyimide molding having high dimensional accuracy can be produced.

[Process for producing thermoplastic polyimide]

The method for producing the thermoplastic polyimide of the present invention is not limited. For example, after the thermal imidation reaction process using the specific acid dianhydride and the specific diamine compound described below as raw materials, the end sealing reaction Process and / or chemical imidization process. The end sealing reaction step and the chemical imidization step may be carried out in an orderly manner, and they may be carried out at the same time. It is preferable that the end sealing reaction step and the chemical imidization step are performed after the end sealing reaction step.

[Raw material]

The thermoplastic polyimide of the present invention can be usually obtained by using an acid anhydride and a diamine compound as a raw material. As the raw material for the thermoplastic polyimide of the present invention, a compound having an alicyclic structure in at least one of an acid dianhydride and a diamine compound is used, and it is preferable to use an acid dianhydride having an alicyclic structure in view of raw material procurement and productivity Do.

(Hereinafter may be referred to as "H-BPDA") represented by the following formula (5) and an acid dianhydride (hereinafter referred to as "H-BPDA") represented by the following formula (6) as raw materials for the thermoplastic polyimide of the present invention, Quot; PMDA ") may be used. Further, H-BPDA is a known compound and can be obtained, for example, by the method described in Japanese Patent Laid-Open Publication No. 2011-45877. Also, H-PMDA is a known compound and can be obtained, for example, by the method described in JP-A-2009-191253.

(7)

In addition, it is preferable to use a diamine compound represented by the following formula (7) as a raw material for the thermoplastic polyimide of the present invention.

[Chemical Formula 8]

In the formula (7), R ^{1 '} to R ^8' are defined similarly to R ¹ to R ⁸ in the formula (3), and X 'is defined similarly to X. Also, n 'is defined similarly to n.

Examples of the diamine compound represented by the formula (7) include 4,4'-diaminodiphenyl ether (hereinafter sometimes referred to as ODA), 2,2'-dimethyl-4,4'-dia Bis (4-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-aminophenoxy) benzene, Bis (4-aminophenoxy) phenyl] propane, 4,4'-bis (4-aminophenoxy) biphenyl, 2,2'-bis (4-aminophenyl) terephthalate, bis (trifluoromethyl) -4,4'-diaminobiphenyl, 4,4'-diaminobenzoyl anilide, 4- (4-aminophenoxy) phenyl) sulfone, and bis (4-amino-3-carboxyphenyl) methane. Of these, 4,4'-diaminodiphenyl ether, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) Minobiphenyl and the like are preferable. These acid dianhydrides may be used alone or in combination of plural kinds.

The thermoplastic polyimide of the present invention may be used in combination with an acid anhydride other than H-BPDA and H-PMDA as raw materials. Examples of the acid dianhydrides other than H-BPDA and H-PMDA include ethylene tetracarboxylic acid dianhydride, butanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, 1,2,3,4 (2,3-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) (3,4-dicarboxyphenyl) methane dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2-bis , 2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride , 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, 3,3 ', 4,4'-benzophenonetet (P-phenylenedioxy) diphthalic acid dianhydride, 4,4- (m-phenyl) dicarboxylic acid dianhydride, 2,2 ', 3,3'-benzophenonetetracarboxylic acid dianhydride, Naphthalenedicarboxylic acid dianhydride, 1,2,5,6-naphthalenedicarboxylic acid dianhydride, 1,4,5,8-naphthalenedicarboxylic acid dianhydride, 2,3,6,7-naphthalenedicarboxylic acid dianhydride 2, 3, 4-benzenetetracarboxylic acid dianhydride, 2,2 ', 6,6'-biphenyltetracarboxylic acid dianhydride, 3,4,9,10-phe Anthracene tetracarboxylic acid dianhydride, 2,3,7-anthracene tetracarboxylic acid dianhydride, and 1,2,7,8-phenanthrene tetracarboxylic acid dianhydride, Or a combination of plural species may be used. When an acid dianhydride other than H-BPDA and H-PMDA is used, it is usually 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less, % Or less.

The thermoplastic polyimide of the present invention may be used as a raw material in combination with a diamine compound other than the diamine compound represented by the formula (7). Examples of the diamine compound other than the diamine compound represented by the formula (7) include 1,2-phenylenediamine, 1,3-phenylenediamine, 3,4'-diaminodiphenyl ether, 1,3 ' Bis (3-aminophenoxy) benzene, 4,4'-bis (3-aminophenoxy) benzene, (Aminophenoxy) benzene, bis (4- (3-aminophenoxy) phenyl) sulfone, 1,3-bis Phenoxy) neopentane, bis (4-amino-3-carboxyphenyl) methane, 1,4-diaminocyclohexane, 4,4'- methylenebis (cyclohexylamine), 4,4'- (4-aminophenyl) -5-1H-benzoxazole, 2,2-bis (3-methylphenyl) (3-amino-4-hydroxyphenyl) propane, and 2,2-bis (3-amino-4-hydroxylphenyl) hexafluoropropane. , These And also using one species may be used in combination of plural kinds. When a diamine compound other than the diamine compound represented by the above formula (7) is used, it is usually 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less based on all the diamine compounds used as a raw material % Or less.

In the thermoplastic polyimide of the present invention, the ratio of the acid dianhydride and the diamine compound used as the raw material is preferably 0.8 mol or more, and more preferably 1.0 mol or less, Many are more desirable. On the other hand, it is preferably 1.2 mol or less, and more preferably 1.1 mol or less. When the ratio of the acid dianhydride to the diamine compound used as the raw material is in the above range, polyimide having a large molecular weight tends to be obtained and polyimide toughness is preferably obtained. Particularly, the use of more than 1.0 mol of the diamine compound for the acid dianhydride is preferable because the end amino group is controlled to be larger than the acid anhydride end and the end sealing of the acid anhydride increases the sealing ratio of the terminal amino group of the finally obtained polyimide. This is because when the acid dianhydride is larger than the diamine compound, polyimide whose terminal is an acid anhydride is easily obtained, and in order to seal the terminal of the acid anhydride, it is necessary to use an encapsulating agent having an amino group.

[Thermal imidation reaction step]

In the present invention, the term " heat-imidization reaction step " means a step of carrying out the imidization reaction (condensation and dehydration cyclization reaction) by mixing the raw materials and, if necessary, a solvent and a catalyst and heating them.

Examples of the solvent used in the thermal imidation reaction include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide. Among these, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like are preferable. These solvents may be used alone, or two or more solvents may be used in combination. In addition, it is preferable that the solvent used here is left as it is to carry out a terminal sealing reaction or a chemical imidization reaction.

Examples of the catalyst used in the thermal imidation reaction include trimethylamine, triethylamine, tripropylamine, tributylamine, triethanolamine, pyridine, N, N-dimethylethanolamine, N, There may be mentioned triethylenediamine, N-methylpyrrolidine, N-ethylpyrrolidine, N-methylpiperidine, N-ethylpiperidine, imidazole, quinoline and isoquinoline. These catalysts may be used alone or in combination of two or more.

The reaction temperature in the thermal imidation reaction is preferably 120 to 200 占 폚, more preferably 130 to 190 占 폚. The thermal imidation reaction may be carried out under atmospheric pressure (0.1 MPa), under reduced pressure or under reduced pressure, and is usually carried out under atmospheric pressure. The reaction time for the heat-imidization reaction is usually 2 hours or more, and preferably 4 hours to 20 hours.

The thermal imidation reaction is preferably carried out in an inert gas atmosphere, and is preferably carried out under a nitrogen atmosphere, for example. Further, in order to sufficiently proceed the thermal imidation reaction, it is preferable to remove the water generated by the imidization reaction, and the removal efficiency of water can be improved by adding an azeotropic dehydrating agent such as toluene or xylene to the solvent.

[Terminal sealing reaction step]

In the present invention, the term " end sealing reaction step " means a step of sealing the terminal amino group of the polyimide with a terminal sealing agent.

The terminal sealing agent used in the terminal sealing reaction step is not particularly limited as long as it is capable of reacting with an amino group to form a stable structure, and examples thereof include phthalic anhydride, succinic anhydride, 1,2-cyclohexanedicarboxylic acid anhydride, Acid anhydrides such as 4-methylcyclohexane-1,2-dicarboxylic acid anhydride and (2-methyl-2-propenyl) succinic acid anhydride; And organic acid chlorides such as benzoic acid chloride. The above-mentioned end sealants may be used alone or in combination of plural kinds. When the terminal acid anhydride group of the thermoplastic polyimide of the present invention is sealed, an amine compound such as 3-aminophenylacetylene, aniline, or cyclohexylamine may be used as a terminal sealing agent. However, the sealing of the terminal anhydride group does not correspond to the sealing of the terminal amino group in the present invention.

The amount of the end sealant to be used is preferably 1 to 10 times the equivalent number of the diamine compound used as the raw material and the difference in the number of moles of the acid dianhydride (the amount of the unreacted primary amino group) Is 2 to 8 times the equivalent number. If the amount of the end sealant used is higher than the lower limit, the sealing ratio of the terminal amino group is increased. On the other hand, if the upper limit is not exceeded, the treatment of the untreated end sealant is less preferred. In the case where the chemical imidization reaction step described later is not carried out, it is preferable to increase the amount of the end sealant used to increase the sealing ratio of the terminal amino group.

The terminal sealing reaction is preferably carried out in a solvent. Examples of the solvent used in the terminal sealing reaction include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide. Among these, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like are preferable. These solvents may be used alone, or two or more solvents may be used in combination.

The reaction temperature in the end-sealing reaction step is usually 80 to 200 ° C, preferably 120 to 200 ° C. The thermal imidation reaction may be carried out under atmospheric pressure (0.1 MPa), under reduced pressure or under reduced pressure, and is usually carried out under atmospheric pressure. The reaction time of the terminal sealing reaction is usually 1 hour or more, preferably 2 hours to 10 hours.

[Chemical Imidization Reaction Process]

In the present invention, the "chemical imidization reaction step" generally means a step of mixing the polyimide, the organic amine compound and the dehydrating condensing agent in a solvent to carry out an imidation reaction.

Examples of the organic amine compound used in the chemical imidization reaction step include tertiary alkylamines such as trimethylamine, triethylamine, tripropylamine and tributylamine; Alkanolamines such as triethanolamine, N, N-dimethylethanolamine and N, N-diethylethanolamine; Alkylenediamines such as triethylenediamine; Pyridines such as pyridine; Pyrrolidines such as N-methyl pyrrolidine and N-ethyl pyrrolidine; Piperidines such as N-methylpiperidine and N-ethylpiperidine; Imidazoles such as imidazole; And quinolines such as quinoline and isoquinoline. These catalysts may be used alone or in combination of two or more. The amount of the organic amine compound to be used is preferably 0.1 wt% or more and less than 15 wt%, more preferably 0.5 wt% or more and less than 5 wt%, based on the solid content of the polyimide resin.

Examples of the dehydrating condensing agent used in the chemical imidization reaction step include acid anhydrides such as acetic anhydride, trifluoroacetic anhydride, and chloroacetic anhydride; N, N-2-substituted carbodiimides such as N, N-dicyclohexylcarbodiimide and N, N-diphenylcarbodiimide. These dehydrating agents may be used alone or in combination of two or more. The amount of the dehydrating agent to be used is preferably 0.1% by weight or more, more preferably 0.5% by weight or more based on the solid content of the polyimide resin. In order to obtain the thermoplastic polyimide of the present invention, It is preferable to use a large amount of the antioxidant, specifically, 15 wt% or more. On the other hand, the upper limit of the amount of the dehydrating condensing agent to be used is preferably 30% by weight or less, more preferably 25% by weight or less.

Examples of the solvent used in the chemical imidization reaction step include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide. Among these, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like are preferable. These solvents may be used alone, or two or more solvents may be used in combination.

The reaction temperature of the chemical imidization reaction step is usually from 40 to 200 ° C, preferably from 50 to 160 ° C. The chemical imidization reaction may be carried out under atmospheric pressure (0.1 MPa), under reduced pressure, or under reduced pressure, and is usually carried out under atmospheric pressure. The reaction time of the chemical imidization reaction is usually 30 minutes or more, preferably 1 to 6 hours.

The obtained polyimide is preferably purified by re-precipitation, washing, filtration and the like. By this purification, the raw materials and catalyst remaining in the system can be removed.

[Blending of additives]

Various additives may be added to the thermoplastic polyimide of the present invention within a range not hindering the effect of the present invention. Examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, and an antistatic agent.

Among the additives exemplified above, it is preferable to use an antioxidant. Examples of the antioxidant include phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like. These antioxidants may be used alone or in combination of two or more.

[Polyimide molded article]

By molding the thermoplastic polyimide of the present invention, a polyimide molded article can be obtained.

[Molding method]

In the present invention, the molding method of the thermoplastic polyimide molding is not particularly limited. The molding method can be adopted for various applications, and examples thereof include an extrusion molding method, an injection molding method, a blow molding method, and a compression molding method. The thermoplastic polyimide-formed body obtained by these methods can be processed by a processing method such as a lamination molding method, a roll processing method, a stretching processing method, a stamping processing method, and a hot pressing method. Among them, the thermoplastic polyimide of the present invention can be molded by melt extrusion molding because the thermoplastic polyimide of the present invention is remarkably excellent in melt thermal stability as described above. In addition, From the viewpoint that it can be efficiently produced.

The molding conditions of the thermoplastic polyimide molded article are not particularly limited. When extrusion molding is carried out, it is possible to use any one of a single-screw extruder and a twin-screw extruder. The temperature of the cylinder of the extruder is typically 280 ° C to 380 ° C, and the polyimide extruded from the die is cooled in the cooling roll. The temperature of the cooling roll is usually 0 ° C to 60 ° C.

[Properties]

The thermoplastic polyimide molded article of the present invention is excellent in transparency. The transparency of the thermoplastic polyimide molded article is evaluated by the total light transmittance according to JIS K 7105 (1981), preferably 70% or more, more preferably 75% or more, further preferably 80% Particularly preferably 85% or more. The thickness of the thermoplastic polyimide film at this time is not particularly limited, but is usually 0.01 to 10 mm, preferably 0.02 to 5 mm, and particularly preferably 0.03 to 1 mm.

[Usage]

The thermoplastic polyimide molding obtained from the thermoplastic polyimide of the present invention is excellent in transparency, heat resistance, solvent resistance, moldability, solvent nonvolatility and the like. Therefore, the present invention can be applied not only to film applications, which are typical applications of polyimide molded articles, but also to a wide variety of applications. For example, a member for a flexible solar cell, a member for a display, a tray for IC packaging, an IC socket, an IC socket, a wafer carrier, a connector, a socket, a hard disk carrier, a liquid crystal display carrier, , Heat insulating bearings for copiers, gears for copiers, thrust washers, transmission rings, piston rings, oil seals, bearing retainers, pump gears, conveyor chains, slide bushes for stretch machines, thermal insulation tape, heat resistant adhesive tape, Base, condenser, or film for a flexible printed circuit board. It is also used for the production of a structural member reinforced with glass fiber, carbon fiber, or the like, a bobbin of a small-sized coil, or a molded product of a terminal insulating tube. It can also be used for manufacturing a laminated material such as an insulating spacer, a magnetic head spacer, or a spacer of a transformer. It can also be used for the production of enamel coatings such as wire and cable insulation coatings, low temperature storage tanks, space insulation or integrated circuits. It can also be used for the production of yarns, fabrics or nonwoven fabrics having heat resistance.

Example

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless they exceed the gist thereof. The values of the various production conditions and the evaluation results in the following examples have a meaning as preferable values of the upper limit or the lower limit in the embodiment of the present invention. The preferable range is the value of the upper limit or the lower limit , The values in the following embodiments, or the values in the embodiments.

[Evaluation method of polyimide]

The evaluation methods of the structure and physical properties of the polyimide produced in the following examples are as follows.

[Sealing rate of terminal amino group]

The sealing rate of the terminal amino group was determined by ¹ H-NMR measurement as follows.

The integral value of the ortho-position peak (6.75 ppm) with respect to the terminal amino group by the ODA constituent unit in the polyimide was defined as S ₁ , and the integrated value of the peak (7.61 ppm) shifted by sealing the amino terminal was defined as S ₂ . From these values, the sealing ratio of the terminal amino group was determined by the following formula.

(Sealing ratio of terminal amino group) = 100 x [S ₂ / (S ₁ + S ₂ )]

( ¹ H-NMR measurement conditions)

Solvent: DMF-d7 (N, N-dimethylformamide-d7)

Frequency: 400 ㎒

Standard substance: DMF-d7 2.74 ppm

Accumulation count: 256 times

Mitigation Time: 1 second

[Imidization rate]

The imidization rate was obtained from the NMR chart obtained in the measurement of the sealing ratio of the terminal amino group from the residual ratio of amic acid as follows.

Five protons of the H-BPDA constituent units in the polyimide were observed at 1.0 to 2.0 ppm.

And the sum of the integral values of the peak group was defined as S ₃ . The integrated value of the peak (9.3 to 10.3 ppm) due to the amide hydrogen of the amic acid structure remaining in the polyimide was defined as S ₄ . From these values, the imidization rate was obtained by the following formula.

(Imidization rate) = 100 x [1 - (5S ₄ / S ₃ )]

[Weight average molecular weight (Mw)]

The weight average molecular weight in terms of polystyrene of the polyimide relating to the present invention was determined by the following method by gel permeation chromatography (GPC). First, GPC of standard polystyrene was measured under the following conditions, and a calibration curve was prepared. Subsequently, the GPC of the sample (polyimide) was measured under the same conditions, and the average molecular weight in terms of polystyrene was determined.

(GPC measurement conditions)

Column: Three Shodex AD-80M / S manufactured by Showa Denko Corporation

Free column: 1 Shodex KF-G manufactured by Showa Denko Corporation

Solvent: N, N-dimethylformamide (containing LiBr 50 mmol / l)

Flow rate: 1.0 ml / min

Temperature: Column 35 ° C

Sample concentration: 0.5 wt%

Detector: UV detector

Correction Samples: Monodisperse Standard Polystyrene

[Complex shear viscosity (? ^* )? Change rate of complex shear viscosity]

The initial complex shear viscosity (? ^* ₀ ) at a frequency of 1 Hz and the complex shear viscosity (? ^* ₆₀ ) after 60 minutes under the following measurement conditions were measured using a rotary rheometer (ARES- Respectively.

(Rotating type rheometer measurement condition)

A horizontal plate having a diameter of 25 mm was used as a jig for the time dispersion measurement of the rotating type rheometer (ARES).

Measuring temperature: 310 ° C

Each frequency: 1 rad / s

Strain: 1%

Warm-up time: 5 minutes

Measurement time: 0 to 60 minutes

[Synthesis of 3,3 ', 4,4'-bicyclohexyltetracarboxylic acid dianhydride (H-BPDA)]

≪ Synthesis Example 1 &

150 parts by weight of 3,3 ', 4,4'-biphenyltetracarboxylic acid dianhydride (manufactured by Mitsubishi Chemical Corporation) were dissolved in a solution prepared by dissolving 83.3 parts by weight of sodium hydroxide in 593 parts by weight of water, An aqueous solution of 4,4'-biphenyltetracarboxylic acid sodium salt was prepared and the salt was hydrogenated at 120 ° C using a ruthenium / carbon catalyst at 10 MPaG (relative pressure to atmosphere). Subsequently, 429 parts by weight of a 49% sulfuric acid aqueous solution was added dropwise, and the precipitated solid was filtered to obtain 3,3 ', 4,4'-bicyclohexyltetracarboxylic acid (H-BTC).

33.7 parts by weight of the obtained H-BTC and 90 parts by weight of acetic anhydride were added to the reactor under nitrogen. The mixture was heated while stirring and reacted at a reflux temperature (130 ° C to 140 ° C) for 3 hours. After the reaction, the reaction solution was cooled to 10 DEG C and the solid was filtered to obtain white crystals. The crystals obtained were washed with toluene and dried in a vacuum dryer to obtain 3,3 ', 4,4'-bicyclohexyltetracarboxylic acid dianhydride (H-BPDA).

[Production of polyimide]

≪ Example 1-1 >

60.0 parts by weight of the H-BPDA obtained in Synthesis Example 1, 40.0 parts by weight of 4,4-diaminodiphenyl ether (ODA), 40.0 parts by weight of N, N 200 parts by weight of dimethylacetamide and 95 parts by weight of toluene were added. Subsequently, the inside of the reactor was changed to a nitrogen atmosphere, and the internal temperature was heated to 145 占 폚 to carry out the heat imidation reaction. The water accompanying the imidization was azeotropically removed with toluene. When heating, refluxing and stirring were continued for 12 hours, no occurrence of water was observed.

Subsequently, 2.2 parts by weight of phthalic anhydride was added, and the mixture was stirred at 145 DEG C for 3 hours to carry out a terminal sealing reaction. After stirring for 3 hours, the reaction mixture was heated for 1 hour while removing toluene under reduced pressure. After the inner temperature was cooled to 60 占 폚, 1.0 part by weight of triethylamine and 2.0 parts by weight of acetic anhydride were added and the mixture was stirred at 60 占 폚 for 3 hours to carry out a chemical imidization reaction to obtain a polyimide solution. The obtained polyimide solution was added dropwise to methanol, and the precipitated polyimide was collected by filtration, dried under reduced pressure at 80 占 폚 for 3 hours, and dried at 150 占 폚 under reduced pressure for 3 hours to obtain a polyimide solid. Table 1 shows the physical properties of the obtained polyimide.

≪ Example 1-2 >

A polyimide was obtained in the same manner as in Example 1-1, except that the composition of the raw material was changed to the composition shown in Table 1 in Example 1-1. Table 1 shows the physical properties of the obtained polyimide.

≪ Example 1-3 >

A polyimide was obtained in the same manner as in Example 1-1, except that pyridine was used instead of triethylamine in Example 1-1, and the raw material composition was changed to the composition shown in Table 1-1. Table 1 shows the physical properties of the obtained polyimide.

≪ Example 1-4 >

59.1 parts by weight of the H-BPDA obtained in Synthesis Example 1, 40.9 parts by weight of 4,4-diaminodiphenyl ether (ODA), 40.9 parts by weight of N, N 200 parts by weight of dimethylacetamide and 95 parts by weight of toluene were added. Subsequently, the inside of the reactor was changed to a nitrogen atmosphere, and the internal temperature was heated to 145 占 폚. Water accompanying the imidization was azeotropically removed with toluene. When heating, refluxing and stirring were continued for 12 hours, no occurrence of water was observed.

Subsequently, 6.0 parts by weight of phthalic anhydride was added, and the mixture was stirred at 145 占 폚 for 3 hours. After stirring for 3 hours, the polyimide solution was obtained by heating for 1 hour while removing toluene under reduced pressure. The obtained polyimide solution was dropped into methanol, and the precipitated polyimide was recovered by filtration, dried at 80 ° C under reduced pressure for 3 hours, and then dried at 150 ° C under reduced pressure for 3 hours to obtain a polyimide solid. Table 1 shows the physical properties of the obtained polyimide.

<Examples 1-5 to 1-7>

A polyimide was obtained in the same manner as in Example 1-1, except that the composition of the raw material was changed to the composition shown in Table 1 in Example 1-1. Table 1 shows physical properties of each of the obtained polyimides.

&Lt; Example 1-8 &gt;

60.0 parts by weight of the H-BPDA obtained in Synthesis Example 1, 40.0 parts by weight of 4,4-diaminodiphenyl ether (ODA), 40.0 parts by weight of N, N 200 parts by weight of dimethylacetamide and 95 parts by weight of toluene were added. Subsequently, the inside of the reactor was changed to a nitrogen atmosphere, and the internal temperature was heated to 145 占 폚. Water accompanying the imidization was azeotropically removed with toluene. When heating, refluxing and stirring were continued for 12 hours, no occurrence of water was observed.

Subsequently, after the internal temperature was cooled to 60 占 폚, 10 parts by weight of triethylamine and 20 parts by weight of acetic anhydride were added and stirred at 60 占 폚 for 3 hours to obtain a polyimide solution. The obtained polyimide solution was dropped into methanol, and the precipitated polyimide was recovered by filtration, dried at 80 ° C under reduced pressure for 3 hours, and then dried at 150 ° C under reduced pressure for 3 hours to obtain a polyimide solid. Table 1 shows physical properties of each of the obtained polyimides.

&Lt; Example 1-9 &gt;

A polyimide was obtained in the same manner as in Example 1-4 except that the raw material composition was changed to the composition shown in Table 1 in Example 1-4. Table 1 shows the physical properties of the obtained polyimide.

<Example 1-10>

A polyimide was obtained in the same manner as in Example 1-1, except that the composition of the raw material was changed to the composition shown in Table 1 in Example 1-1. Table 1 shows the physical properties of the obtained polyimide.

&Lt; Example 1-11 &

A polyimide was obtained in the same manner as in Example 1-8 except that the raw material composition was changed to the composition shown in Table 1 in Example 1-8. Table 1 shows the physical properties of the obtained polyimide.

&Lt; Comparative Examples 1-1 to 1-5 &gt;

A polyimide was obtained in the same manner as in Example 1-1, except that the composition of the raw material was changed to the composition shown in Table 2 and the end sealing step and the chemical imidization step were not carried out in Example 1-1. Table 2 shows the physical properties of the obtained polyimide.

As can be seen from Tables 1 and 2, the polyimides obtained in Examples 1-1 to 1-11 had a change rate of the complex shear viscosity of 300% or less, And was superior in melt thermal stability, and was a polyimide suitable for melt extrusion molding. In particular, in Examples 1-1 to 1-8, the change rate of the complex shear viscosity was 100% or less and the melt thermal stability was remarkably excellent.

[Evaluation of polyimide molded article]

The evaluation methods of the structure and physical properties of the polyimide produced in the following examples are as follows.

[Heat resistance: glass transition temperature (Tg)]

The storage elastic modulus and loss elastic modulus of the sample with respect to the vibration load of the sample were measured using a dynamic thermomechanical measuring device (DMS / SS6100, manufactured by SII Nanotechnology Co., Ltd.) under the following measurement conditions to determine a glass transition temperature (Tg ) Were obtained. The higher the Tg, the better the heat resistance.

(DMS measurement conditions)

The peak temperature of the loss tangent (tan?) Obtained by dividing the storage elastic modulus (E ') of the test piece by the loss elastic modulus (E ") was defined as the glass transition temperature.

Measuring temperature range: 50 캜 to 400 캜 (rate of temperature rise: 2 캜 / min)

Tensile load: 5 g

Sample shape: 10 mm x 10 mm

Sample thickness: listed in Table 3

[Transparency: total light transmittance]

For the polyimide film, the total light transmittance was measured according to JIS K 7105 (1981). The higher the total light transmittance, the better the transparency. When the total light transmittance was 70% or more, the light transmittance was determined to be acceptable.

[Solvent nonvolatility: amount of residual solvent]

(TG / DTA6200, manufactured by SII Nanotechnology Co., Ltd.) under the following measurement conditions. 20 mg of the polyimide piece or the polyimide melt-formed body was heated from 40 占 폚 to 100 占 폚 at a temperature raising rate of 20 占 폚 / min and then stopped at 100 占 폚 for 130 minutes. Thereafter, the temperature was raised from 100 占 폚 to 350 占 폚 at a heating rate of 10 占 폚 / min, and the weight loss from 150 占 폚 to 300 占 폚 was defined as the residual solvent content. The lower the value, the better the solvent nonvolatility.

[Production of polyimide molded article]

&Lt; Example 2-1 &gt;

The polyimide obtained in Example 1-1 was fed to a single-screw extruder, melted at 330 캜, extruded onto a cooling roll set at 120 캜, cooled and solidified to obtain a polyimide film having a thickness of 100 탆. The obtained polyimide film was subjected to the above evaluation. The results are shown in Table 3.

&Lt; Example 2-2 &gt;

The polyimide obtained in Example 1-2 was fed to a biaxially stretching extruder, and the resin strand obtained by melting at 330 DEG C was cooled and then the strand was cut into a pelletizer to obtain a polyimide pellet. The obtained polyimide pellets were fed to a single-screw extruder, melted at 330 캜, extruded onto a cooling roll set at 120 캜, cooled and solidified to obtain a polyimide film having a thickness of 100 탆. The obtained polyimide film was subjected to the above evaluation. The results are shown in Table 3.

&Lt; Example 2-3 &gt;

A polyimide film was obtained in the same manner as in Example 2-2 except that the polyimide film had a thickness of 50 mu m. The obtained polyimide film was subjected to the above evaluation. The results are shown in Table 3.

As can be seen from Table 3, it can be seen that the polyimide films obtained in Examples 2-1 to 2-3 are excellent in transparency and heat resistance. Particularly, the weight loss before and after heating is small and the solvent nonvolatility is excellent.

While the invention has been described in detail and with reference to specific embodiments thereof, it is evident to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The present application is based on Japanese Patent Application (Japanese Patent Application No. 2012-274901) filed on December 17, 2012, the content of which is incorporated herein by reference.

Claims (9)

A thermoplastic polyimide having an alicyclic structure, a terminal amino group having a sealing ratio of 95.0% or more, and an imidization rate of 95.8% or more. The method according to claim 1,
A thermoplastic polyimide having a weight average molecular weight (Mw) of 10,000 to 500,000. 3. The method according to claim 1 or 2,
Wherein the alicyclic structure is a cyclohexane ring structure. 4. The method according to any one of claims 1 to 3,
Wherein the alicyclic structure shares two carbon atoms with the imide ring structure and is an adjacent structure. 5. The method according to any one of claims 1 to 4,
As the alicyclic structure, a thermoplastic polyimide having at least one of a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2).
[Chemical Formula 1]

6. The method according to any one of claims 1 to 5,
A thermoplastic polyimide further having a structural unit represented by the following formula (3).
(2)

(3), R ¹ to R ⁸ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms or a hydroxyl group, X is a direct bond, A sulfur atom, an alkylene group having 1 to 4 carbon atoms, a sulfonyl group, a sulfonyl group, a sulfide group, a carbonyl group, an amide group, an ester group or a secondary amino group and n is an integer of 0 to 4) 7. The method according to any one of claims 1 to 6,
A thermoplastic polyimide having a complex shear viscosity (? ^* ) At 310 占 폚 of 1 × 10 ² to 5 × 10 ⁵ Pa · s. 8. The method according to any one of claims 1 to 7,
And a change rate of a complex shear viscosity before and after elapse of 60 minutes at 310 占 폚 of 300% or less. A thermoplastic polyimide molded article obtained by melt extrusion molding the thermoplastic polyimide described in any one of claims 1 to 8.