JPH06200026A - Method for producing curable oligomer - Google Patents

Abstract

(57) [Summary] [Structure] Keep the reaction system below room temperature in an inert gas atmosphere, and add trimellitic anhydride dissolved in an aprotic polar solvent to a mixed solution of paratoluenesulfonic acid chloride and pyridine. Then, a diol compound previously dissolved in an aprotic polar solvent is added and reacted, and then an organic tetracarboxylic dianhydride or its derivative dissolved in an aprotic polar solvent is added, followed by dissolution in an aprotic polar solvent. The resulting diamine is reacted in an amount sufficient to obtain a telechelic oligoamic acid terminated with acid anhydride groups at both ends, and the primary amine dissolved in an aprotic polar solvent is added to terminate the reaction, and then the non-solvent is used. A method for producing a curable imide oligomer, which comprises thermally dehydrating and ring-closing with addition of a compound. [Effect] A polyimide oligomer that provides a cured product having excellent processability, heat resistance, mechanical strength, and dimensional stability can be easily produced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a curable oligomer. More specifically, the present invention relates to a method for producing an imide oligomer that provides a polyimide having excellent heat resistance, good solubility in an organic solvent, and reactivity suitable for lamination and molding.

[0002]

2. Description of the Related Art Thermosetting resins are used as various electrical insulating materials, structural materials, etc. as casting, impregnating, laminating and molding materials. In recent years, the usage conditions of materials have become more and more severe in each of these uses, and the heat resistance of materials has become an important characteristic. For applications that require heat resistance,
Conventionally, thermosetting polyimide resins and heat resistant epoxy resins have been used. Among them, as the thermosetting polyimide resin, kelimide containing a combination of a bismaleimide compound and diaminodiphenylmethane as a main component is used (Matsuo Fujisawa, Plastics, Vol. 34, No. 7, 7).
5 pages, 1983).

Recently, for example, a thermosetting polyimide in which 3-aminophenylacetylene is used as a primary amine and the terminal is terminated is put on the market as thermid (Hughes Aircraft, JP-A-50-5348, etc.). Several methods (for example, USP 4,125,563) are known for the synthesis of 3-aminophenylacetylene used here, but all have the problems that the synthetic route is long and the synthetic reagents are expensive. Was there. Further, a thermosetting polyimide in which propargylamine is used as a primary amine and the end of which is terminated is also proposed (Ube Industries, Ltd., JP-A-2-284923, JP-A-3-1744).
27). However, the thermal reaction initiation temperature of the propargyl group is 2
It is as high as 50 ° C., and the imide oligomer using this as a reactive group has a high curing temperature and is known to be inferior in terms of processability [“Polymer Engineering Science (Polym. Eng. Sci)”, 22. (1), 9-14 (198
2)]. Further, generally, polyimide resins have poor moisture absorption resistance, and it has been pointed out that dimensional stability in the processing step is a problem.

In order to solve such problems of polyimide, various resin improving methods have been proposed, and various polyesterimide resins have been proposed in view of processing characteristics (for example, USP 4, No. 757,118, 4,362,861
No. 3,852,246, etc., or JP-A-1-13819
etc). However, in general, polyester imide has a lower softening point and a better resin fluidity than polyimide, but it is pointed out that it is inferior to polyimide in terms of heat resistance [Kurita Keisuke et al., Polymer Processing, Volume 37, Vol. No., 22-26 (1989)]. Furthermore, as in the present invention, using trimellitic anhydride as a starting monomer and a paratoluenesulfonic acid chloride / pyridine-based reaction solvent to synthesize a novel acid dianhydride having an ester bond, and then introducing a diamine or the like. There is only a little knowledge about synthesizing polyesterimide in the same reaction system by the method described in H. Tanaka et al., Proceedings / Ah.
stracts of Third InternatinalConference On Polyimi
des, 65-68 pp (1988)], let alone much knowledge about thermosetting type or photo-reactive polyesterimide.

[0005]

DISCLOSURE OF THE INVENTION The present invention can easily produce a polyimide oligomer having excellent processability, high heat resistance, and a cured product having excellent mechanical strength, dimensional stability, and electrical characteristics. It provides a method.

[0006]

The present inventors have arrived at the present invention as a result of earnest studies to solve these technical problems in view of such circumstances. That is, the present invention keeps the reaction system at room temperature or below in an inert gas atmosphere,
After adding trimellitic anhydride dissolved in an aprotic polar solvent to a mixed solution of p-toluene chloride and pyridine, the diol compound HO- represented by the general formula (1) previously dissolved in an aprotic polar solvent is added. Ar ₁ —OH (1) (wherein Ar ₁ represents a divalent aromatic group) is added and reacted, and then the compound is dissolved in an aprotic polar solvent to give the general formula (2).

[0007]

[Chemical 8]

(Wherein Ar ₂ represents a tetravalent aromatic group) or an organic tetracarboxylic dianhydride represented by the general formula (3)

[0009]

[Chemical 9]

(In the formula, Y1, Y2, Y3 and Y4 are hydrogen,
An alkyl group selected from C1 to 5, Ar ₂ is a tetravalent aromatic group), and an acid dianhydride derivative represented by the following formula (4) H ₂ N- is dissolved in an aprotic polar solvent. Ar ₃ --NH ₂ (4) (wherein Ar ₃ represents a divalent organic group) is added with an amount of diamine represented by the following formula to provide a telechelic oligoamic acid terminated with acid anhydride groups at both ends. Reacted and further dissolved in an aprotic polar solvent, the general formula (5)

[0011]

[Chemical 10]

(In the formula, R represents a substituent having reactivity.) An acid anhydride represented by the formula is added to terminate the terminal, and then a nonsolvent is added to thermally dehydrate the ring. And a method for producing a curable imide oligomer.

First, the method for producing the curable oligomer of the present invention will be described in detail. The necessary amount of paratoluenesulfonic acid chloride (hereinafter referred to as TsCl) was weighed out in a sufficiently dried inert atmosphere such as argon or nitrogen, and the reaction system was kept at room temperature or lower, preferably 10%.
After cooling to ℃ or less, more preferably under ice-cooling, pyridine is added dropwise from a syringe while paying attention to heat generation. After sufficient reaction, a calculated amount of trimellitic anhydride (hereinafter referred to as TMA) is dissolved in an aprotic polar solvent and then added. Then, the diol compound represented by the general formula (1) is dissolved in the same aprotic polar solvent as described above under ice cooling, and then added. The reaction is appropriately performed even at room temperature to complete the reaction. Here, in order to obtain the copolymer, it is possible to add an acid dianhydride represented by the general formula (2) or an acid dianhydride derivative represented by the general formula (3). Next, the reaction system is ice-cooled again, and the organic diamine compound represented by the general formula (4) dissolved in the same aprotic polar solvent as described above is added. At this time, it is important to add a calculated amount of the diamine compound in advance so as to obtain a telechelic oligoesteramic acid solution having both acid anhydride groups terminated. After the oligoamic acid solution is sufficiently reacted, a primary amine having a thermosetting group represented by the general formula (5) dissolved in the same aprotic polar solvent as described above is used to terminate the oligomer terminal. To obtain an oligoamic acid solution which is a precursor of a reactive imide oligomer.

Finally, in order to thermally dehydrate and ring-close the oligoamic acid solution, a non-solvent is added and then converted to polyimide under reflux and azeotropy. As the non-solvent used here, xylene, which is an aromatic hydrocarbon, or toluene can be used,
Preferably toluene is used. In the reaction, water to be azeotropically distilled off is refluxed using a Dean-Stark reflux device until a theoretical amount of water is collected. The dehydration ring closure reaction to this imide structure can also use the chemical ring closure method together. After the reaction, the polyimide solution is poured into water or an alcoholic solvent with vigorous stirring to precipitate the polyimide as a powder. The powder is collected by filtration and then dried at 80 ° C. under reduced pressure for 48 hours.

As the organic tetracarboxylic dianhydride used in the present invention, organic tetracarboxylic dianhydrides having any structure can be used.
The group represented by (3) is preferable, and the Ar group is preferably a tetravalent organic group and is preferably an aromatic group. This Ar ₂
Specific examples of the group include the following.

[0016]

[Chemical 11]

[0017]

[Chemical 12]

Preferably, at least one of the following is selected.

[0019]

[Chemical 13]

As the Ar ₃ group of the diamine represented by the above general formula (4) used in the present invention, any divalent organic group can be used. Specific examples include the following.

[0021]

[Chemical 14]

[0022]

[Chemical 15]

Preferably, at least one of the following is selected.

[0024]

[Chemical 16]

Ar of the diol compound used in the present invention
₁ is essentially any divalent organic group, but specifically,

[0026]

[Chemical 17]

[0027]

[Chemical 18]

Can be illustrated. An aromatic group is particularly desirable, and specifically,

[0029]

[Chemical 19]

It is preferable to use at least one of the above as a main component. Illustrating the reactive functional group R represented by the general formula (5) used in the present invention for terminating the terminal,

[0031]

[Chemical 20]

From the viewpoint of cost and handling, it is preferable that

[0033]

[Chemical 21]

It is Examples of the organic solvent used in the reaction for producing a polyamic acid solution include, for example, dimethyl sulfoxide, sulfoxide-based solvents such as diethyl sulfoxide,
Examples thereof include formamide solvents such as N, N′-dimethylformamide and N, N′-diethylformamide, acetamide solvents such as N, N′-dimethylacetamide and N, N′-diethylacetamide. These may be used alone or as a mixed solvent of two or three or more. Furthermore, with these polar solvents, methanol, ethanol, isopropanol, benzene,
It can also be used as a mixed solvent with a non-solvent of polyamic acid such as methyl cellosolve. Further, the oligomer of the present invention can be used in combination with so-called B-stage formation, if necessary, when inducing a thermosetting reaction. B-stage conversion is 100 ° C. or higher, preferably 15
0 ° C or higher, more preferably 200 ° C or higher, 1 minute or longer,
It is preferable that the heating is carried out for 5 minutes or longer under hot air circulation under vacuum or under vacuum.

Although the mechanism for the particularly high heat resistance of the reactive polyimide of the present invention is not clear, formation of a benzene skeleton by thermosetting acetylene / acetylene or [3,3] sigmatropy of propargyl ether. It is said that the effect is due to the formation of the chromene skeleton by the transition / formation of the polymer by ring-opening thermosetting. [For example, 3rd International Sampe Electric Conference (3rd. Int. SAMPE Elect. Conf.) 16
Page 9, 1989, Dow Chemical. , JP 2-8
5275] Also, the number average degree of polymerization [Principles of Polymer Chemistry (Principles of Polymer Chem
istry), page 91, 1953], the degree of polymerization n is preferably 0 to 30, more preferably 0 to 20, and still more preferably 1 to 15. If it is more than that, there is a drawback that the solubility in the organic solvent decreases. Further, if it is less than that, a problem appears in terms of mechanical strength.

In obtaining a thermosetting resin from the curable oligomer of the present invention, known epoxy resin or epoxy resin curing agent, curing accelerator, filler, flame retardant, reinforcing agent, surface treatment agent, pigment may be used, if necessary. The various elastomers can be used alone or in combination of two or more. These thermosetting resins are not limited in their usage and can be applied in various modes. Among them, electrical laminates, so-called PWB
It can also be used as a matrix resin for (printed wiring board). When used for PWB applications, various fillers and reinforcing agents can be used. Examples of the filler include aluminum hydroxide, antimony trioxide, red phosphorus and the like. As the reinforcing material, carbon fiber, glass fiber, aramid fiber, liquid crystal polyester fiber such as Vectra, polybenzothiazole (PBT) fiber, woven fabric made of alumina fiber, non-woven fabric, mat, paper (paper) or a combination thereof is used. It can be illustrated.

[0037]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples, and the present invention is within the scope of the invention. The present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art. Reference Example 1 Production of 4-acetamidophenyl-1-propargyl ether A 50-ml dropping funnel, a 3-way cock, and a seal cap were attached to a 300-ml three-necked flask, and dried and replaced with nitrogen under reduced pressure. After charging 15.12 g (0.1 mol) of 4-acetamidophenol and 3.22 g (0.01 mol) of tetra-n-butylammonium bromide into the reactor, 4 g (0.1 mol) of sodium hydroxide was added to the reactor.
A solution dissolved in 30 ml water was added. Reaction temperature 50
After raising to ℃ and dissolving 4-acetamidophenol,
13.09 g (0.11 mol) of propargyl bromide was added from the dropping funnel over about 30 minutes. After reacting at 50 ° C. for 4 hours, the mixture was stirred overnight at room temperature. The precipitated crystals were filtered out and recrystallized from ethanol. 18.1
g (95.5%) of propargyl ether was obtained.

[Elemental analysis value] Calculated value: C; 69.83, H; 5.86, N; 7.40 Actual value: C; 69.78, H; 5.98, N; 7.33 [Spectrum Data] IR (neat, cm ⁻¹ ) ν = 3500, 3300, 296
0,2880,1880,1650,1610,156
0,1510,1450,1370,1270,124
0,1180,1030,840,810,660,6
30 1 H-NMR (CDCl ₃ , ppm) δ = 2.12
(S., 3H), 2.48 (tr., 1H), 4.61.
(D., J = 2.4 Hz, 2H), 6.77 to 7.6.
(M., 4H), 7.85 (br.s., 1H)

Reference Example 2 Preparation of 4-acetamidophenyl-1-allyl ether In Reference Example 1, propargyl bromide 13.09
g (0.11 mol) of allyl bromide 13.31 g
Except having changed to (0.11 mol), it carried out similarly to the reference example 1, and obtained 18.1 g (94.6%) of 4-acetamidophenyl-1-allyl ether.

[Elemental analysis value] Calculated value: C; 69.09, H; 6.85, N; 7.32 Actual value: C; 69.31, H; 6.64, N; 7.47 [Spectrum Data] IR (neat, cm ⁻¹ ) ν = 3500, 3300, 296
0,1880,1620,1620,1560,150
0,1470,1370,1270,1220,124
0,1150,1030,860,810,660 1H-NMR (CDCl ₃ , ppm) δ = 2.14
(S., 3H), 3.75 (s., J = 2.0Hz, 2
H), 5.23 (m., 2H), 5.96 (m., 1)
H), 8.0 (m., 4H)

Reference Example 3 Production of 4-aminophenyl-1-propargyl ether A 300-ml three-necked flask was equipped with a 50-ml dropping funnel, a three-way cock, and a sealum cap, and dried and replaced with nitrogen under reduced pressure. 5.68 g (0.03 mol) of 4-acetamido-1-propargyl ether and 150 g of 3N hydrochloric acid were charged into the reaction system and reacted under reflux for 4 hours. After the reaction, the reaction solution was poured into a saturated sodium carbonate solution and extracted from methylene chloride. The organic layer was dehydrated and filtered, and the solvent was distilled off. The precipitated crystals were recrystallized from ethanol to obtain 4.18 g (yield; 94.7%) of 4-aminophenyl-1-propargyl ether.

[Elemental analysis value] Calculated value: C; 73.46, H; 6.12, N; 9.5
2. Found: C; 73.85, H; 5.98, N; 9.8.
6. [Spectral data] IR (neat, cm ^-1 ) ν = 3600-3000, 300
0,2950,1620,1600,1580,149
5,1450,1350,1295,1220,116
0,990,905,860,780,735,69
0. 1H-NMR (CDCl ₃ , ppm) δ = 2.5 (t
r. , 1H), 3.5 (br.s., 2H), 4.75.
(D., J = 1.2 Hz, 1H), 6.7 (m., 4
H)

Reference Example 4 Preparation of 4-aminophenyl-1-allyl ether 5.68 g (0.03 mol) of 4-acetamido-1-propargyl ether in Reference Example 3 was replaced with 19.12 g of 4-acetamido-1-allyl ether. (0.1 mol)
In the same manner as in Reference Example 3, except that the amount of 3N hydrochloric acid was changed from 150 g to 200 g.
0.3%) of 4-aminophenyl-1-allyl ether was obtained.

[Elemental analysis value] Calculated value: C; 80.74, H; 5.81, N; 13.4
5 Found: C; 80.53, H; 5.98, N; 13.8.
1 [Spectral data] IR (neat, cm ⁻¹ ) ν = 3600-3000,300
0,2950,1620,1600,1580,149
5,1450,1350,1295,1220,116
0,990,905,860,780,735,690 ¹ H-NMR (chloroform-d, ppm) δ = 3.
5 (tr., 1H), 4.2 (br.s., 2H),
5.15 (d., J = 1.2 Hz, 1H), 6.7
(M., 4H)

Example 1 A one-liter four-necked flask was equipped with a three-way cock, a Dean Stark still, a Dimroth reflux condenser, and a searum cap, and the reactor was dried under reduced pressure. 9.53g
After adding (50 mmol) TsCl to the reaction system, it was thoroughly replaced with nitrogen. The reaction system was ice-cooled and 20 ml of dry pyridine was added while paying attention to the exotherm. 9.61 g (50 mmol) of trimellitic anhydride was dissolved in 70 ml of dry N, N'-dimethylformamide (DMF) and then added into the system within 30 minutes. After continuing the reaction at that temperature, 5.71 g (25 mmol) of bisphenol A dissolved in 20 ml of dry DMF was added dropwise under ice cooling. After 30 minutes, the ice bath was removed, and the reaction was continued at room temperature for 1 hour. After that, 30 ml
16.11 g of 4,4 ', 3, dissolved in dry DMF of
3'-Benzophenonetetracarboxylic acid dianhydride was added to the system, the reaction system was cooled again with ice, and 10.96 g (37.5 mmol) of 1,3-bis (3-aminophenoxybenzene) was added to 30 ml of dry DMF. ) Was added. After 30 minutes, the ice bath was removed, the reaction system was heated in an oil bath at 60 ° C., and the reaction was continued for 30 minutes. 1 to 15 ml dry DMF
1.04 g (75 mmol) of 4-aminophenyl-1-propargyl ether obtained in Reference Example 3 was added and reacted for 2.6 hours. Then, 200 ml of dry toluene was added, and then 5.5 ml (theoretical amount:
5.4 ml) of water of reaction was distilled off and dehydration ring closure was performed to obtain an imide oligomer having the following structure. 1.5 after reaction
The imide oligomer formed was precipitated by pouring the reaction solution into liter of methanol. The precipitated imide oligomer was filtered under reduced pressure and dried in vacuum at 80 ° C. for 48 hours to obtain 48.38 g (yield: 97.1%) of an oligomer as a pale yellow powder. [Spectral data] IR (neat, cm ⁻¹ ) ν = 3000, 2950, 178
0,1750,1700,1630,1600,158
0,1495,1440,1350,1295,122
0,1160,990,910,860,780,73
5,690.

When the oligomer was B-staged by melting and defoaming in a vacuum oven at 220 ° C., it became a reddish brown powder. Using 8.3 g of B-staged imide oligomer, 220 ° C. for 20 minutes, 250 ° C. for 30 minutes
Min., 270 ° C., 1 hour, pressed under contact pressure, having a density of 1.39 g / cm ³ 12 mm (width) × 12 cm (length)
A cast plate of × 3.4 mm (thickness) was obtained. This casting plate is 5
A flexural strength of 8.8 kg / mm ^2, and the flexural modulus of 315 kg / mm ^2, and impact strength of 35kg · cm / cm ^2, was a resin having a glass transition temperature of 253 ℃ (Tg). The moisture absorption rate was 0.27% (C-96 / 20/65).

Example 2 Instead of 10.96 g (37.5 mmol) of 1,3-bis (3-aminophenoxy) benzene, 7.96 g (3
An imide oligomer having the following structure was obtained in the same manner as in Example 1 except that 7.5 mmol of 3,3'-diaminobenzophenone was used. [Spectral data] IR (neat, cm ⁻¹ ) ν = 3000, 2950, 178
0,1750,1700,1620,1600,158
0,1495,1450,1350,1295,122
0,1160,990,905,860,780,73
5,690.

When the oligomer was B-staged by melting and defoaming in a vacuum oven at 220 ° C., it became a reddish brown powder. Using 8.9 g of B-staged imide oligomer, 220 ° C. for 20 minutes, 250 ° C. for 30 minutes
Min., 270 ° C., 1 hour, pressed under contact pressure, having a density of 1.36 g / cm ³ 12 mm (width) × 12 cm (length)
A cast plate of × 3.8 mm (thickness) was obtained. This casting plate is 3
A flexural strength of 8.8 kg / mm ^2, and the flexural modulus of 425 kg / mm ^2, and impact strength of 30kg · cm / cm ^2, was a resin having a glass transition temperature of 239 ℃ (Tg). The moisture absorption rate was 0.18% (C-96 / 20/65).

Example 3 11.04 g (75 mmol) of 4-aminophenyl-1-
Instead of propargyl ether, 15.31 g (75
mmol) was used in the same manner as in Example 1 except that 4-aminophenoxy-1-allyl ether obtained in Reference Example 4 was used to obtain an imide oligomer having the following structure. [Spectral data] IR (neat, cm ⁻¹ ) ν = 3000, 2950, 178
0,1750,1700,1620,1600,158
0,1495,1450,1350,1295,122
0,1160,990,905,860,780,73
5,690.

When the oligomer was B-staged by melting and defoaming in a vacuum oven at 220 ° C., it became a reddish brown powder. Using 7.5 g of B-staged imide oligomer, 220 ° C. for 20 minutes, 250 ° C. for 30 minutes
Min., 270 ° C, 1 hour, pressed under contact pressure, having a density of 1.37 g / cm ³ 12 mm (width) x 12 cm (length)
A cast plate of × 3.8 mm (thickness) was obtained. This casting plate has 4
A flexural strength of 8.8 kg / mm ^2, and the flexural modulus of 415kg / mm ^2, and impact strength of 25kg · cm / cm ^2, was a resin having a glass transition temperature of 238 ℃ (Tg). The moisture absorption rate was 0.21% (C-96 / 20/65).

Comparative Example Using 9.2 g of a commercially available imide type thermosetting oligomer, 220 ° C. for 20 minutes, 250 ° C. for 30 minutes, 270 ° C.
Pressed under contact pressure for 1 hour, density 1.35g / cm ³
12mm (width) × 12cm (length) × 3.5mm (thickness)
To obtain a casting plate. The cast plate has a flexural strength of 38.2kg / mm ^2, and a flexural modulus 261kg / mm ^2, 18kg · cm
/ Cm ² impact strength and glass transition temperature (T
g)). Moisture absorption rate is 0.75% (C
-96/20/65).

[0052]

EFFECTS OF THE INVENTION According to the present invention, an oligomer which provides a cured product having excellent processing characteristics and extremely high heat resistance which has never been obtained can be easily obtained. Furthermore, the curable oligomer synthesized according to the present invention has excellent mechanical strength, dimensional stability, electrical characteristics, etc., and in particular, it is possible to provide a polyimide in which voids and cracks are less likely to occur in a molded product. As described above, since the curable oligomer obtained by the production method of the present invention has many characteristics,
It is possible to provide a material having an extremely high industrial value for a wide range of applications such as a laminated plate, a heat resistant coating, a polymer material for electronic devices, and a molding material, and its utility is extremely large.

Claims (6)

[Claims] 1. A reaction system is kept at room temperature or below in an inert gas atmosphere, trimellitic anhydride dissolved in an aprotic polar solvent is added to a mixed solution of paratoluenesulfonic acid chloride and pyridine, and then aprotic acid is added. A diol compound represented by the general formula (1) HO-Ar ₁ -OH (1) (wherein Ar ₁ represents a divalent aromatic group) previously dissolved in a polar polar solvent is added and reacted, Then, the compound of the general formula (2) dissolved in an aprotic polar solvent (Wherein Ar ₂ represents a tetravalent aromatic group) or an organic tetracarboxylic dianhydride represented by the general formula (3) (In the formula, Y1, Y2, Y3 and Y4 are hydrogen, an alkyl group selected from C1 to 5 and Ar ₂ is a tetravalent aromatic group), an acid dianhydride derivative represented by A diamine represented by the general formula (4) H ₂ N—Ar ₃ —NH ₂ (4) (wherein Ar ₃ represents a divalent organic group) dissolved in a polar solvent is used as an acid anhydride group at both terminals. A compound of the general formula (5): embedded image was prepared by adding an amount necessary to obtain a stopped telechelic oligoamic acid, and further reacting it in an aprotic polar solvent. (In the formula, R represents a reactive substituent.) A primary amine represented by the formula is added to terminate the terminal, and then a non-solvent is added to thermally dehydrate ring closure. For producing a photosensitive imide oligomer. 2. The production method according to claim 1, wherein Ar ₁ is at least one selected from the following. [Chemical 4] 3. The production method according to claim 1, wherein Ar ₂ is at least one selected from the following. [Chemical 5] 4. The production method according to claim 1, wherein Ar ₃ is at least one selected from the following. [Chemical 6] 5. The production method according to claim 1, wherein R is at least one selected from the following. [Chemical 7] 6. The method according to claim 1, wherein the aprotic polar solvent is dimethylformamide.