JP2023034768A - reaction accelerator - Google Patents

Abstract

To provide a reaction accelerator capable of further accelerating a polymerization reaction involving a condensation reaction.SOLUTION: There is provided a reaction accelerator used for a polymerization reaction involving a condensation reaction which comprises: at least one compound (A) selected from the group consisting of a basic compound having a 5-membered nitrogen-containing heterocyclic ring containing a nitrogen atom to which an alkyl group is bonded as a substituent as a constituent atom of the heterocyclic ring and a basic compound having a six-membered nitrogen-containing heterocyclic ring containing a nitrogen atom to which an alkyl group is bonded as a substituent as a constituent atom of the heterocyclic ring; and at least one compound (B) selected from the group consisting of acetic acid, γ-valerolactone and δ-valerolactone.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a reaction accelerator, and more particularly to a reaction accelerator used for promoting a polymerization reaction accompanied by a condensation reaction.

BACKGROUND ART Conventionally, various reaction accelerators have been used in polymerization reactions involving condensation reactions. As such a reaction accelerator, for example, in JP-A-2017-133027 (Patent Document 1), a tetracarboxylic dianhydride and an aromatic diamine are heated in a solution and polymerized to obtain a polyimide. It is disclosed that a tertiary amine can be suitably used in the reaction (polymerization reaction in such polyimide production involves condensation reaction). We are using. In the field of such reaction accelerators, the appearance of new reaction accelerators capable of further accelerating the reaction is desired.

JP 2017-133027 A

The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a reaction accelerator capable of further promoting a polymerization reaction that accompanies a condensation reaction.

As a result of intensive studies to achieve the above object, the present inventors have found that the reaction accelerator used in the polymerization reaction that accompanies the condensation reaction is A basic compound having a 5-membered nitrogen-containing heterocyclic ring containing at least one compound (A) selected from the group consisting of; at least one compound (B) selected from the group consisting of acetic acid, γ-valerolactone and δ-valerolactone; Surprisingly, when the polymerization reaction accompanied by the condensation reaction is carried out for the same time as compared with the case of using a conventional reaction accelerator, it is possible to further increase the logarithmic viscosity of the resulting polymer. The inventors have found that the polymerization reaction can be further accelerated, and have completed the present invention.

That is, the reaction accelerator of the present invention is
A reaction accelerator used in a polymerization reaction involving a condensation reaction,
A basic compound having a 5-membered nitrogen-containing heterocyclic ring containing a nitrogen atom to which an alkyl group is bonded as a substituent, and a heterocyclic ring composed of a nitrogen atom to which an alkyl group is bonded as a substituent. at least one compound (A) selected from the group consisting of basic compounds having a 6-membered nitrogen-containing heterocycle as an atom;
at least one compound (B) selected from the group consisting of acetic acid, γ-valerolactone and δ-valerolactone;
It is characterized by including

In the reaction accelerator of the present invention, the compound (A) is a basic compound having an imidazole ring containing, as a ring-constituting atom, a nitrogen atom to which an alkyl group is bonded as a substituent, and an alkyl group as a substituent. is preferably at least one selected from the group consisting of basic compounds having a piperidine ring containing a nitrogen atom as a ring-constituting atom.

Moreover, in the reaction accelerator of the present invention, the alkyl group is preferably one selected from the group consisting of methyl, ethyl and propyl groups.

Furthermore, in the reaction accelerator of the present invention, the compound (A) is preferably at least one selected from the group consisting of 1,2-dimethylimidazole and 1-ethylpiperidine.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the reaction accelerator which can accelerate the polymerization reaction accompanying a condensation reaction more.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to its preferred embodiments.

The reaction accelerator of the present invention is a reaction accelerator used for a polymerization reaction involving a condensation reaction,
A basic compound having a 5-membered nitrogen-containing heterocyclic ring containing a nitrogen atom to which an alkyl group is bonded as a substituent, and a heterocyclic ring composed of a nitrogen atom to which an alkyl group is bonded as a substituent. at least one compound (A) selected from the group consisting of basic compounds having a 6-membered nitrogen-containing heterocycle as an atom;
at least one compound (B) selected from the group consisting of acetic acid, γ-valerolactone and δ-valerolactone;
It is characterized by including

The compound (A) according to the present invention is a basic compound having, as a substituent, the nitrogen-containing heterocyclic ring of a five-membered ring containing, as a constituent atom of the heterocyclic ring, a nitrogen atom to which an alkyl group is bonded, and an alkyl At least one compound (basic compound) selected from the group consisting of basic compounds having a 6-membered nitrogen-containing heterocyclic ring containing a nitrogen atom to which a group is bonded as a constituent atom of the heterocyclic ring. A compound that can be selected as such a compound (A) has a 5- or 6-membered nitrogen-containing heterocyclic ring in its structure, and the nitrogen atom contained as a constituent atom of the nitrogen-containing heterocyclic ring At least one of them is a compound (basic compound) having a structure in which an alkyl group is bonded as a substituent. Thus, the compound that can be selected as the compound (A) is a structural portion in which an alkyl group is bonded as a substituent to the nitrogen atom that constitutes the nitrogen-containing heterocycle (the nitrogen atom that constitutes the nitrogen-containing heterocycle It is a compound containing a structural portion in which a bonded hydrogen atom is substituted with an alkyl group).

The 5-membered nitrogen-containing heterocyclic ring and the 6-membered nitrogen-containing heterocyclic ring are not particularly limited, and examples thereof include pyrrolidone ring, piperidone ring, imidazole ring, pyridine ring, pyrrole ring, pyrimidine ring, morpholine ring, Pyrrolidine ring, piperidine ring, piperazine ring, pyrazine ring and the like are included. From the viewpoint of basicity, availability, etc., the 5-membered and 6-membered nitrogen-containing heterocyclic rings are more preferably imidazole rings, piperidine rings, and pyridine rings, and particularly preferably imidazole rings and piperidine rings. .

In addition, the compound (A) has an alkyl group as a substituent from the viewpoint of having a moderate boiling point that can be used even under relatively high temperature conditions (for example, 130 ° C. to 220 ° C.) from the group consisting of a basic compound having an imidazole ring containing as a ring-constituting atom a nitrogen atom to which More preferably, at least one is selected.

In addition, the 5- or 6-membered nitrogen-containing heterocyclic ring in the structure of the compound that can be selected as the compound (A) contains, as a constituent atom of the heterocyclic ring, a nitrogen atom to which an alkyl group is bonded as a substituent. there is In such a compound (A), the alkyl group preferably has 1 to 7 carbon atoms (more preferably 1 to 3 carbon atoms, more preferably 1 to 2 carbon atoms). When the number of carbon atoms in such an alkyl group is equal to or less than the upper limit, compared with the case where the upper limit is exceeded, when molding the resulting polymer, a molded product of the polymer (e.g., film) It tends to be possible to more easily prevent the compound (A) from remaining inside, and to suppress deterioration of the physical properties of the polymer due to the residue at a higher level.

In the compound (A), the alkyl group is preferably a methyl group, an ethyl group, or a propyl group, more preferably a methyl group or an ethyl group, from the viewpoint of availability and boiling point. The nitrogen-containing heterocyclic ring in the compound that can be selected as the compound (A) may have a plurality of nitrogen atoms to which alkyl groups are bonded as substituents.

Compounds that can be used as the compound (A) are not particularly limited, but 1,2-dimethylimidazole, 1-ethylpiperidine (also known as N-ethylpiperidine), 1-methylpiperidine, 2-methylpiperidine , 4-methylpiperidine, 1-methylimidazole, 2-methylimidazole, 1-butylimidazole, 1-(4-methoxyphenyl)-1H-imidazole, and 1-phenylimidazole can be preferably used. Further, among such compounds, 1,2-dimethylimidazole, 1-ethylpiperidine, and 1-phenylimidazole are more preferable as the compound (A), since a higher reaction promoting effect can be obtained. 2-dimethylimidazole and 1-ethylpiperidine are particularly preferred.

The compound (B) is at least one compound selected from the group consisting of acetic acid, γ-valerolactone and δ-valerolactone. By using such a compound (B) in combination with the compound (A), the polymerization reaction accompanied by the condensation reaction can be further accelerated, although the reaction mechanism and the like are not necessarily clear. In addition, although the reaction mechanism and the like are not necessarily clear, among the compounds (B), γ-valerolactone and δ-valerolactone contribute to the reaction by reacting with water during the condensation reaction to form an acid. The present inventors are inferring that.

From the viewpoint of availability and workability, γ-valerolactone is more preferable as such a compound (B).

Further, the reaction accelerator of the present invention contains the compound (A) and the compound (B). The molar ratio of compound (A) to compound (B) ([compound (A)]:[compound (B)]) in the reaction accelerator of the present invention is 0.9:1.1 to 1.9:1.1. It is preferably 1:0.9 (more preferably 0.95:1.05 to 1.05:0.95). When the content of the compound (A) is at least the lower limit, there is a tendency to obtain a higher effect in promoting the reaction than when it is less than the lower limit. In some cases, there is a tendency to obtain a higher effect in promoting the reaction than when the upper limit is exceeded.

The type of polymerization reaction using the reaction accelerator of the present invention is not particularly limited as long as it involves a condensation reaction. By using the reaction accelerator of the present invention in a polymerization reaction involving a condensation reaction, the resulting polymer (polymer) can be obtained when the reaction is carried out for the same time as compared with the case where a conventional reaction accelerator is used. It becomes possible to further improve the logarithmic viscosity. Further, according to such a reaction accelerator of the present invention, compared with the case of using a conventional reaction accelerator, the amount of polymer necessary for making the molecular weight of the obtained polymer (polymer) a desired size is required. It is also possible to make the time (required time) shorter (make the reaction proceed faster).

The polymerization reaction that accompanies such a condensation reaction is not particularly limited, but for example, a polymerization reaction in which a polyimide is obtained by heating a tetracarboxylic dianhydride and a diamine in a solution to proceed with the polymerization reaction ( Polymerization reaction for obtaining polyimide) can be mentioned as a suitable one. In addition, in the polymerization reaction for obtaining such a polyimide, by heating the tetracarboxylic dianhydride and the diamine in a solution, the addition polymerization reaction between the tetracarboxylic dianhydride and the diamine (polyamic A reaction to form an acid) and a subsequent condensation reaction (reaction to form a polyimide from the polyamic acid) proceed almost simultaneously as a series of reactions to form a polyimide. In addition, in the polymerization reaction for obtaining polyimide, the reaction mechanism and the like are not necessarily clear, but the reaction accelerator of the present invention is a process in which tetracarboxylic dianhydride and diamine react to form a polyamic acid, and , polyamic acid undergoes an intramolecular condensation reaction to form a polyimide.

Hereinafter, a suitable example of a polymerization reaction accompanied by a condensation reaction, "a polymerization reaction in which a polyimide is obtained by heating a tetracarboxylic dianhydride and a diamine in a solution to proceed with the polymerization reaction (hereinafter, sometimes referred to as , simply referred to as “polymerization reaction for obtaining polyimide”)”, a preferred method of using the reaction accelerator of the present invention will be described.

When the polymerization reaction for obtaining the polyimide is performed, the specific method and the reaction conditions are not particularly limited except for using the reaction accelerator of the present invention as a reaction accelerator. Known conditions (for example, methods and conditions described in JP-A-2017-133027) can be employed. When performing a polymerization reaction for obtaining such a polyimide, among others, a mixed solution of a solvent, a tetracarboxylic dianhydride, a diamine, and the reaction accelerator of the present invention is prepared, and the mixed solution is added to 130 C. to 220.degree. C. (particularly preferably 150.degree. C. to 200.degree. C.) to allow the polymerization reaction accompanied by the condensation reaction to proceed in a solvent.

As such a solvent, a known solvent that can be used for polyimide polymerization can be appropriately used. As such a solvent, γ-butyrolactone, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N,N-dimethylformamide, from the viewpoint of being able to further improve the solubility of the polyimide, Dimethylsulfoxide, hexamethylphosphoramide, tetramethylenesulfone, p-chlorophenol, m-cresol, 2-chloro-4-hydroxytoluene can be mentioned as suitable. Such solvents can be used singly or in combination of two or more.

Moreover, the tetracarboxylic dianhydride and diamine used in the polymerization reaction for obtaining the polyimide are not particularly limited, and known compounds can be appropriately selected and used according to the design of the polyimide. Examples of such tetracarboxylic dianhydrides and diamines include compounds having an aliphatic structure (e.g., tetracarboxylic dianhydrides having an alicyclic structure, diamines having a chain aliphatic structure, alicyclic Diamines having a formula structure, etc.), compounds having an aromatic structure (eg, tetracarboxylic dianhydrides having an aromatic structure, diamines having an aromatic structure) may be utilized. The tetracarboxylic dianhydride and diamine are preferably selected appropriately so that a polyimide that can be dissolved in a solvent can be produced. In addition, as such a tetracarboxylic dianhydride and diamine, since the resulting polyimide has a higher solvent solubility, either one of the tetracarboxylic dianhydride and the diamine has an alicyclic structure. Alternatively, both the tetracarboxylic dianhydride and the diamine are preferably compounds having an alicyclic structure, and the tetracarboxylic dianhydride is a compound having an alicyclic structure (alicyclic tetracarboxylic acid dianhydride having the formula structure) and the diamine is an aromatic compound (aromatic diamine).

Regarding the tetracarboxylic dianhydrides, tetracarboxylic dianhydrides having an alicyclic structure are considered to have lower reactivity than tetracarboxylic dianhydrides having an aromatic structure. Among aromatic diamines, electron-withdrawing aromatic diamines such as 2,2′-bis(trifluoromethyl)benzidine (abbreviated as “TFMB”) are considered to have low reactivity. be done. The reaction accelerator of the present invention is used when producing a polyimide by combining such monomers with low reactivity (a tetracarboxylic dianhydride having an alicyclic structure and an aromatic diamine having an electron-withdrawing property ( For example, even when used in combination with TFMB), the polymerization reaction can proceed efficiently. Therefore, the reaction accelerator of the present invention can be suitably used for a polymerization reaction in which a polyimide is produced by reacting a tetracarboxylic dianhydride having an alicyclic structure with an aromatic diamine. I can say.

Moreover, the tetracarboxylic dianhydride having the alicyclic structure, which can be suitably used as such a tetracarboxylic dianhydride, is not particularly limited, but among them, norbornane-2-spiro -α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (abbreviation "CpODA"), the following formula (1) ~ ( 2):

(the compound represented by the above formula (1) (abbreviation “BNBDA”), the compound represented by the above formula (2) (abbreviation “BzDA”)), bicyclo[2.2.2]octo -7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, tetrahydrofuran-2,3 ,4,5-tetracarboxylic dianhydride, bicyclo-3,3′,4,4′-tetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2 ,3,4-cyclobutanetetracarboxylic dianhydride and 1,2,3,4-cyclopentanetetracarboxylic dianhydride can be mentioned as suitable examples.

Further, the tetracarboxylic dianhydride having an aromatic structure (aromatic tetracarboxylic dianhydride), for example, pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4' -biphenylsulfonetetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)propanoic dianhydride, hydroquinone bis(trimellitate anhydride), 1,4,5,8-naphthalene Examples include tetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and the like.

In addition, the aromatic compound (aromatic diamine) suitable as the diamine is not particularly limited, and known compounds can be used as appropriate. For example, 2,2′-bis(trifluoromethyl)benzidine (abbreviated as “TFMB”) can also be used as appropriate. Examples of such aromatic diamines include TFMB, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene and 2,4-diaminodurene. , 4,4′-methylenedianiline, 4,4′-methylenebis(3-methylaniline), 4,4′-methylenebis(3-ethylaniline), 4,4′-methylenebis(2-methylaniline), 4 , 4′-methylenebis(2-ethylaniline), 4,4′-methylenebis(3,5-dimethylaniline), 4,4′-methylenebis(3,5-diethylaniline), 4,4′-methylenebis(2 ,6-dimethylaniline), 4,4′-methylenebis(2,6-diethylaniline), 4,4′-oxydianiline, 3,4′-oxydianiline, 3,3′-oxydianiline, 2 ,4'-oxydianiline, 2,2'-oxydianiline, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone , 4,4′-diaminobenzanilide, benzidine, 3,3′-dihydroxybenzidine, 3,3′-dimethoxybenzidine, o-tolidine, m-tolidine, 1,4-bis(4-aminophenoxy)benzene, 1 ,4-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 4,4′-bis(4-aminophenoxy) biphenyl, bis(4-(3-aminophenoxy)phenyl)sulfone, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 2, 2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, p-terphenylenediamine and the like.

Examples of diamines having an aliphatic structure, such as the diamines having an alicyclic structure and the diamines having a chain aliphatic structure, include 4,4′-methylenebis(cyclohexylamine), 4, 4′-methylenebis(3-methylcyclohexylamine), 4,4′-methylenebis(3-ethylcyclohexylamine), 4,4′-methylenebis(3,5-dimethylcyclohexylamine), 4,4′-methylenebis(3 ,5-diethylcyclohexylamine), isophoronediamine, trans-1,4-cyclohexanediamine, cis-1,4-cyclohexanediamine, 1,4-cyclohexanebis(methylamine), 2,5-bis(aminomethyl)bicyclo [2.2.1] heptane, 2,6-bis(aminomethyl)bicyclo[2.2.1]heptane, 3,8-bis(aminomethyl)tricyclo[5.2.1.0]decane, 1 ,3-diaminoadamantane, 2,2-bis(4-aminocyclohexyl)propane, 2,2-bis(4-aminocyclohexyl)hexafluoropropane, 1,3-propanediamine, 1,4-tetramethylenediamine, 1 ,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine and the like.

Further, in the polymerization reaction for obtaining the polyimide, the amount of the reaction accelerator of the present invention is not particularly limited. The amount of (A) is preferably 0.05 to 2 mol (more preferably 0.1 to 1 mol). The amount of the reaction accelerator used in the present invention is such that the amount of compound (B) used in the reaction accelerator is 0.05 to 2 mol (more preferably 0.05 to 1 mol of tetracarboxylic dianhydride). 1 to 1 mol). When the amount of each of the compounds (A) and (B) is equal to or higher than the lower limit, there is a tendency to obtain a higher effect in promoting the reaction than when the amount is less than the lower limit. On the other hand, when it is equal to or less than the upper limit, there is a tendency that a higher effect in terms of suppressing side reactions can be obtained compared to when the upper limit is exceeded. Further, the amount of the tetracarboxylic dianhydride used in the polymerization reaction for obtaining the polyimide is not particularly limited, but from the viewpoint of polymerization reactivity, The amount of all acid anhydride groups in the resulting tetracarboxylic dianhydride is preferably 0.9 to 1.1 molar equivalents (more preferably 0.95 to 1.05 molar equivalents).

Furthermore, in the polymerization reaction for obtaining the polyimide, the amount of the solvent used is not particularly limited, but from the viewpoint of the solubility and polymerization reactivity of the polyimide, the tetracarboxylic dianhydride and the diamine It is preferable that the total amount is 10 to 50% by mass (more preferably 15 to 35% by mass).

By carrying out the polymerization reaction for obtaining the polyimide in this way, the polyimide can be produced efficiently, and the logarithmic viscosity, which is an index of the molecular weight of the polyimide, can be made sufficiently high. The type of polyimide obtained in this way is not particularly limited, and depending on the type of monomer, it may be a so-called all-aliphatic polyimide, which is produced by combining an aliphatic monomer and an aromatic monomer. It may be a semi-aromatic polyimide (semi-aliphatic polyimide), or a wholly aromatic polyimide. The polyimide thus obtained is preferably soluble in a solvent from the viewpoint of high moldability. A polyimide dissolved in such a solvent can be prepared by appropriately selecting monomers (tetracarboxylic dianhydride and diamine) to be used from known monomers.

As described above, the preferred method of using the reaction accelerator of the present invention has been described by citing a case where it is used in a polymerization reaction for obtaining a polyimide as a suitable example, but the polymerization reaction ( Polymerization reaction accompanied by condensation reaction) is not limited to the polymerization reaction for obtaining the aforementioned polyimide, and any polymerization reaction accompanied by condensation reaction can be appropriately applied.

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

<About compound abbreviations>
The abbreviations of the compounds used in each example are shown below.
・BzDA: a compound represented by the above formula (2) ・TFMB: 2,2′-bis(trifluoromethyl)benzidine ・GBL: γ-butyrolactone

<Evaluation of properties of polyimide obtained in each example>
<Measurement of logarithmic viscosity of polyimide>
Sampling from the polyimide solution obtained in each example etc., prepare a measurement sample (solvent: N,N-dimethylacetamide (DMAc)) with a concentration of 0.5 g / dL, and keep it in a constant temperature bath at 30 ° C. Viscosity (logarithmic viscosity) was measured using an Ostwald type viscometer (an automatic viscosity measuring device manufactured by CANNON (trade name: "mini-PV-HX")). The results obtained are shown in Tables 1 and 2.

<Measurement of weight average molecular weight (Mw) of polyimide>
The weight average molecular weights (Mw) of the polyimides in the polyimide solutions obtained in Examples 1 to 4 and Comparative Example 1 were measured as follows. That is, by sampling from the polyimide solution obtained in each example etc., preparing a sample for measurement diluted with DMAc, and using a gel permeation chromatography (GPC) measurement device (manufactured by Tosoh Corporation) as a measurement device , Product name: HLC-8320GPC / 4 columns: manufactured by Tosoh Corporation, product name: TSK gel SuperAW4000, 3000, 2500, SuperH-RC), GPC measurement is performed, and the obtained data is converted with polystyrene. Thus, the weight average molecular weight (Mw) of polyimide was obtained. The results obtained are shown in Tables 1 and 2.

(Example 1)
Under a nitrogen stream, 0.9607 g (3 mmol) of diamine TFMB, 0.1802 g (3 mmol) of acetic acid as compound (B), and 7.1 g of GBL as a solvent were added to a 50 mL two-necked flask and heated to 105°C. After dissolving the solid content in the solvent, the mixture was stirred at a temperature of 105°C for 30 minutes to obtain a solution (I). Next, 0.3396 g (3 mmol) of 1-ethylpiperidine as compound (A) and 1.2193 g (3 mmol) of BzDA as tetracarboxylic dianhydride are added to solution (I) to obtain a mixed solution. After that, the temperature is raised to 195° C., and the polymerization reaction is allowed to proceed by reacting at a temperature of 195° C. for 5 hours under a nitrogen atmosphere while appropriately adding GBL so that the liquid volume of the mixed solution is constant. , to obtain a resin solution containing polyimide (polyimide solution: polyimide varnish).

(Examples 2-5)
A resin solution containing polyimide ( Polyimide solution) was obtained. In each example, the amount of compound (A) used and the amount of compound (B) used were set to 3 mmol as shown in Table 1, respectively.

(Comparative example 1)
Except that 3 mmol of triethylamine was used as a comparative component of compound (A) instead of 1-ethylpiperidine, compound (B) was not used, and the amount of GBL used as a solvent was changed as shown in Table 2. A resin solution containing polyimide (polyimide solution) was obtained in the same manner as in Example 1.

(Comparative Examples 2-4)
Except that 3 mmol of triethylamine was used as a comparative component of compound (A) instead of 1-ethylpiperidine, and the amount of GBL used as a solvent and the type of compound (B) were changed as shown in Table 2. A resin solution containing polyimide (polyimide solution) was obtained in the same manner as in Example 1. In each comparative example, the amount of compound (B) used was 3 mmol as shown in Table 2.

(Comparative Examples 5-6)
Except that 3 mmol of pyridine was used as a comparative component of compound (A) instead of 1-ethylpiperidine, and the amount of GBL used as a solvent and the type of compound (B) were changed as shown in Table 2. A resin solution containing polyimide (polyimide solution) was obtained in the same manner as in Example 1. In each comparative example, the amount of compound (B) used was 3 mmol as shown in Table 2.

As is clear from the results shown in Tables 1 and 2, when the compound (A) and the compound (B) were combined and used as a reaction accelerator during polymerization (Examples 1 to 5), the obtained All the logarithmic viscosities of the polyimides were 0.38 or more. On the other hand, when triethylamine was used alone as a reaction accelerator without using the compound (B) (Comparative Example 1), the logarithmic viscosity was 0.36, which is similar to that of Examples 1 to 5. was low in comparison. The logarithmic viscosity of polyimide can be used as an index of molecular weight. In fact, when the weight average molecular weights (Mw) of the polyimides obtained in Examples 1 to 4 and Comparative Example 1 are compared, it is found that compound (A) and compound (B) are produced during polymerization even though the reaction time is the same. When used in combination (Examples 1 to 4), the weight average molecular weight (Mw) was at least 5698 or more than when triethylamine was used alone (Comparative Example 1). From these results, when compound (A) and compound (B) were used in combination as a reaction accelerator (Examples 1 to 5), when triethylamine was used alone as a reaction accelerator (Comparative Example 1 ), it was found that it is possible to promote the polymerization reaction accompanied by the condensation reaction.

Further, from the results shown in Table 2, the logarithmic viscosity of the polyimide obtained when the compound (B) was used in combination with triethylamine as a reaction accelerator (Comparative Examples 2 to 4) was When compared with the logarithmic viscosity of the polyimide obtained in the case of using (Comparative Example 1), the value was low. Therefore, when the compound (B) is combined with triethylamine (Comparative Examples 2 to 4), the effect of promoting the progress of the reaction is greater than when triethylamine is used alone as a reaction accelerator (Comparative Example 1). was found to return and decrease. Furthermore, the logarithmic viscosity of the polyimide obtained when pyridine and the compound (B) are combined and used as a reaction accelerator (Comparative Examples 5-6) are the logarithmic viscosities of the polyimides obtained in Examples 1-5, And compared with the logarithmic viscosity of the polyimide obtained in Comparative Example 1, it was a low value. From these results, it was found that the desired reaction promoting effect could not be obtained by combining compound (B) with triethylamine or pyridine.

Considering the results described above, the polymerization reaction can be further accelerated by combining the compound (B) with a specific compound (A) such as 1-ethylpiperidine or 1,2-dimethylimidazole. It turns out that it is possible to From the results shown in Tables 1 and 2, the reaction accelerator of the present invention can further accelerate the polymerization reaction accompanied by the condensation reaction, and when the reaction is performed for the same time, the molecular weight is increased. It has been found that it is possible to produce large polyimides.

As explained above, according to the present invention, it is possible to provide a reaction accelerator capable of further promoting a polymerization reaction accompanied by a condensation reaction. Thus, the reaction accelerator of the present invention is excellent in terms of the effect of accelerating the polymerization reaction that accompanies the condensation reaction. Therefore, it is useful, for example, as a reaction accelerator used to accelerate the polymerization reaction of polyimide. is.

Claims (4)

A reaction accelerator used in a polymerization reaction involving a condensation reaction,
A basic compound having a 5-membered nitrogen-containing heterocyclic ring containing a nitrogen atom to which an alkyl group is bonded as a substituent, and a heterocyclic ring composed of a nitrogen atom to which an alkyl group is bonded as a substituent. at least one compound (A) selected from the group consisting of basic compounds having a 6-membered nitrogen-containing heterocycle as an atom;
at least one compound (B) selected from the group consisting of acetic acid, γ-valerolactone and δ-valerolactone;
A reaction accelerator characterized by comprising: The compound (A) is a basic compound having an imidazole ring containing a nitrogen atom to which an alkyl group is bonded as a substituent and a nitrogen atom to which an alkyl group is bonded as a substituent. 2. The reaction accelerator according to claim 1, which is at least one selected from the group consisting of basic compounds having a piperidine ring. 3. The reaction accelerator according to claim 1, wherein said alkyl group is one selected from the group consisting of methyl, ethyl and propyl groups. 4. The compound (A) according to any one of claims 1 to 3, wherein the compound (A) is at least one selected from the group consisting of 1,2-dimethylimidazole and 1-ethylpiperidine. Reaction accelerator.