JP2537188B2 - Polyimide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel polyimide.

[Conventional technology]

Conventionally, polyimide obtained by the reaction of tetracarboxylic dianhydride and diamine, due to various excellent physical properties and good heat resistance, is expected to be widely used in the field where heat resistance is required in the future. ing.

Many of the conventionally developed polyimides show excellent properties, but they have excellent heat resistance but are not easy to process, and resins developed for the purpose of improving processability have heat resistance and solvent resistance. There were pros and cons in performance such as inferior

For example, formula (III) Polyimide having a basic skeleton represented by (DuPont Co .; trade name Kapton, Vespel) is a polyimide that does not have a clear glass transition temperature and has excellent heat resistance, but it is processed when used as a molding material. Difficult and must be processed using techniques such as sintering. Also, when used as a material for electrical and electronic parts, it has a property of having a high water absorption that adversely affects dimensional stability, insulation properties, and solder heat resistance.

Also formula (IV) Polyetherimide having a basic skeleton represented by is a resin excellent in processability, but has a low glass transition temperature of 217 ° C and halogenation such as methylene chloride. It is soluble in hydrocarbons and is not a satisfactory resin in terms of heat resistance and solvent resistance.

[Problems to be solved by the invention]

In addition to the excellent heat resistance inherent in polyimide, the object of the present invention is to obtain a polyimide which has excellent processability, low water absorption, excellent solvent resistance, and excellent alkali resistance, and which can be used for multiple purposes. It is in.

[Means for solving problems]

The present inventors have conducted extensive studies to achieve the above object, and as a result, found a novel polyimide.

That is, the present invention has the formula (I) It is composed of repeating units represented by the formula (II) Is a polyimide in which the polyamic acid having a repeating unit represented by is having an inherent viscosity of 0.1 to 4.0 dl / g.

Here, the logarithmic viscosity is a value measured at 35 ° C. in a solution in which 0.5 g of aromatic polyamic acid is dissolved in 100 ml of N, N-dimethylacetamide as a solvent.

The polyimide of the present invention has 4,4′-diamine component.
A novel polyimide obtained by further dehydrating and cyclizing a polyamic acid obtained by polymerizing bis (3-aminophenoxy) biphenyl and pyromellitic dianhydride as a tetracarboxylic dianhydride component. .

And also the polyimide of the present invention, while having the same heat resistance as conventional polyimide, has a characteristic that it is also thermoplastic, therefore it is melt moldable, it is a high heat resistant polyimide excellent in processability. is there.

Furthermore, the polyimide of the present invention is a polyimide having low water absorption, excellent solvent resistance and alkali resistance, and excellent flexibility.

Therefore, the polyimide of the present invention is a very useful polyimide as a base material for space / aircraft and a base material for electric / electronic parts.

 The polyimide of the present invention can be obtained by the following method.

That is, first, 4,4'-bis (3-aminophenoxy)
Biphenyl and pyromellitic dianhydride are polymerized in an organic solvent to obtain a polyamic acid.

The reaction for producing this polyamic acid is usually carried out in an organic solvent. Examples of the organic solvent used in this reaction include N,
N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-
Dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis {2- (2-methoxy Ethoxy) ethyl} ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethylurea,
Hexamethylphosphoramide, m-cresol, P-chlorophenol, anisole and the like can be mentioned. These organic solvents may be used alone or in combination of two or more.

The reaction temperature is usually 200 ° C or lower, preferably 50 ° C or lower.

 The reaction pressure is not particularly limited and can be carried out at normal pressure.

The reaction time depends on the type of solvent and the reaction temperature,
Usually, the reaction is carried out for a sufficient time to complete the production of the polyamic acid represented by the following formula (II). 4-24 hours is usually sufficient.

By such a reaction, a polyamic acid having a repeating unit of the following formula (II) is obtained.

In the present invention, the polyamic acid, which is a polyimide precursor, has an inherent viscosity of 0.1 to 4.0 dl / g, preferably 0.3 to 2.5 dl / g.

Further, the obtained polyamic acid is heated to 100 to 400 ° C. for imidization, or is chemically imidized by using an imidizing agent such as acetic anhydride to obtain a corresponding polyimide having a repeating unit of the following formula (I). Is obtained.

In addition, 4,4′-bis (3-aminophenoxy) biphenyl and pyromellitic dianhydride are suspended or dissolved in an organic solvent and then heated to generate polyamic acid as a precursor of polyimide and dehydration imidization. It is also possible to obtain a polyimide comprising a repeating unit of the above formula (I) by simultaneously performing the above. That is, it is possible to obtain a film-like or powder-like polyimide comprising the repeating unit of the above formula (I) by using a conventionally known method.

〔Example〕

The present invention will be specifically described with reference to Examples, Comparative Examples and Synthesis Examples.

Synthesis Example 3 In a glass reaction vessel, 186 g (1.0 mol) of 4,4'-dihydroxybiphenyl and 438 g (2.6 g of m-dinitrobenzene) were used.
Mol), 363 g of potassium carbonate and 2000 ml of N, N-dimethylformamide are charged and reacted at 145 to 150 ° C for 16 hours.
After completion of the reaction, cooling, the inorganic salt is filtered off, then the solvent of the filtrate is distilled off under reduced pressure, and then cooled to 65 ° C., and methanol is added.
Charge 2000 ml and stir for 1 hour. The crystals are filtered off, washed with water,
The crystals were washed with methanol and dried to obtain brown crystals of 4,4'-bis (3-nitrophenoxy) biphenyl. Yield 426g
(Yield 99.5%). Then, in the glass closed container of 1,
100 g (0.23 mol) of the obtained crude 4,4'-bis (3-nitrophenoxy) biphenyl was charged together with 1 g of 5% Pd / C (manufactured by Nippon Engelhardt) and 350 ml of methyl cellosolve. When hydrogen was introduced with vigorous stirring at 60 to 65 ° C, the reaction was completed after 8 hours without absorbing any more hydrogen. After cooling, the catalyst is removed by filtration, this is discharged into 500 ml of water and the crystals are filtered off. To this, add 48g of 35% hydrochloric acid and 540ml of 50% isopropanol, heat to dissolve, and let cool.
4,4'-bis (3-aminophenoxy) biphenyl hydrochloride was precipitated. After filtering this, 50% isopropanol
Add 540 ml and heat to dissolve, add 5 g of activated carbon and filter,
Neutralize with aqueous ammonia, filter the crystals, wash with water and dry 4,
4'-Bis (3-aminophenoxy) biphenyl was obtained. Yield 72.0g (85% yield), colorless crystals, melting point 144-146
C, purity 99.6% (by high performance liquid chromatography).

MS: 368 (M ⁺ ), 340, 184 IR (KBr, cm ⁻¹ : 3400 and 3310 (NH ₂ group), 1240 (ether bond) Example 1 equipped with a stirrer, reflux condenser and nitrogen inlet pipe In a container, 4,4'-bis (3-aminophenoxy) biphenyl 36.8 g (0.1 mol) and N, N-dimethylacetamide 17
After charging 5.8 g, 21.8 g (0.1 mol) of pyromellitic dianhydride was added in portions at room temperature under a nitrogen atmosphere while paying attention to increase in solution temperature, and the mixture was stirred at room temperature for about 20 hours. The polyamic acid thus obtained had an inherent viscosity of 2.47 dl / g.

A part of this polyamic acid solution was taken, cast on a glass plate, and then heated at 100 ° C., 200 ° C., and 300 ° C. for 1 hour to obtain a pale yellow transparent polyimide film having a film thickness of 25 μm. The tensile strength of this polyimide film is 14.8kg
/ mm ² , Tensile elongation was 70%. (The measuring method is based on ASTM D-882. The same applies to the following.) The glass transition temperature of this polyimide film is 271 ° C (measured by the TMA penetration method. The same applies below), and the temperature at which 5% weight loss occurs in air. Is 545
C (measured by DTA-TG. The same applies hereinafter).

The water absorption of this film when immersed in water at 23.5 ° C for 24 hours was 0.52%. (Measurement method is ASTM
According to D-570-63. The same applies below. Further, the film was immersed in a 30 wt% caustic soda aqueous solution heated to 70 ° C., but no change was observed.

To 150 g of the above polyamic acid solution, 337.5 g of N, N-dimethylacetamide was added and heated to 70 ° C. under stirring in a nitrogen atmosphere, and then 26.1 g (0.26 mol) of acetic anhydride and 9.05 g (0.09 mol) of triethylamine. When, was added dropwise, yellow polyimide powder began to precipitate in about 10 minutes after the completion of the addition, but the mixture was further stirred under heating for 2 hours and then filtered to obtain a polyimide powder. This polyimide powder was washed with methanol and dried under reduced pressure at 150 ° C for 5 hours to yield 34.5g.
Polyimide powder (yield 98%) was obtained. An X-ray analysis of this polyimide powder showed that it had a crystallinity of 21%.

The infrared absorption spectrum of this polyimide powder is shown in FIG. This spectrum diagram, around 1780 cm ^-1 and near 1720 cm ^-1 which is the characteristic absorption band of imide, and absorption at around 1240 cm ^-1 which is the characteristic absorption band of ether linkage was clearly observed.

This polyimide powder was completely insoluble in halogenated hydrocarbon solvents such as methylene chloride and chloroform.

The glass transition temperature of this polyimide powder was 260 ° C, and the melting point was 367 ° C. (Measured by DSC method). The notched Izod strength of the compression molded product obtained by compression molding this polyimide powder at 400 ° C and 300 kg / cm ² for 30 minutes is 18 kgcm / cm.
Met. (The measuring method is based on ASTM D-256. The same applies to the following.) Comparative Example-1 Using a commercially available Kapton 100H (Kapton 100H; trade name of DuPont) which is a polyimide represented by the formula (III). The water absorption measured in the same manner as in Example-1 was 2.9%. Also, when this Kapton film was immersed in a 30 wt% caustic soda solution heated to 70 ° C., it completely dissolved.

Comparative Example-2 A polyimide represented by the above formula (IV), which was a commercially available pellet of Ultem 1000 ULTEM1000; trade name of General Electric Co.) was dissolved in methylene chloride, and 20% by weight or more was dissolved.

Example-2 In a container equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, 368 g (1.0 mol) of 4,4'-bis (3-aminophenoxy) biphenyl and 5215 N, N-dimethylacetamide were added.
Into a nitrogen atmosphere at room temperature, 211.46 g (0.97 mol) of pyromellitic dianhydride was added in portions while paying attention to the rise in solution temperature, and the mixture was stirred at room temperature for about 20 hours. The polyamic acid thus obtained had an inherent viscosity of 0.52 dl / g.
In this polyamic acid solution, at room temperature under a nitrogen atmosphere 404 g
(4 mol) triethylamine and 612 g (6 mol) acetic anhydride were added dropwise. Approximately 1 hour after completion of dropping, yellow polyimide powder began to precipitate. Further, the mixture was stirred at room temperature for about 20 hours and then filtered to obtain a polyimide powder. This polyimide powder was sludged with methanol, separated and separated at 180 ℃.
After drying for 4 hours, 529 g (yield 97.3%) of polyimide powder was obtained.

The infrared absorption spectrum of the polyimide powder thus obtained was the same as in FIG. The X-ray analysis of this polyimide powder showed that it had a crystallinity of 9.3%.

Further, the polyimide powder obtained in this example was used to measure the melt viscosity using a Koka type flow tester (CFT-500 manufactured by Shimadzu Corporation). The orifice is 0.1 cm in diameter and 1 cm in length. The relationship between the shear rate and the melt viscosity obtained by changing the temperature is shown in FIG.

The obtained strand was light brown, transparent and very flexible.

Further, when this polyimide powder was extruded at 390 ° C., a brown transparent tough strand was obtained. This strand was pelletized and injection-molded at 390 ° C. and 500 kg / cm ² to obtain a brown transparent molded product. The tensile yield strength (measurement method is based on ASTM D-638. The same applies hereinafter) of this molded product is 1240 kg / cm ² , and the tensile breaking strength (measurement method is ASTM
According to D-638. The same applies below. ) Is 1110 kg / cm ² , and elongation at break (measurement method is based on ASTM D-638. The same applies hereinafter) is 40.
%, Izod strength with notch is 18.2 kgcm / cm, heat distortion temperature (measurement method is based on ASTM D-648. The same applies below) is 2.
It was 50 ° C.

Comparative Example-3 A commercially available Ultem 1000 was injection-molded under the same conditions as in Example-2, and the physical properties of the obtained molded product were measured.The tensile yield strength was 1090 kg / cm ² , and the tensile breaking strength was 1090 kg / cm ^2. , Breaking elongation 81%, notched Izod strength 4.7 kg ・ cm / c
m, heat distortion temperature was 200 ℃.

Example-3 In a container equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, 36.8 g (0.1 mol) of 4,4'-bis (3-aminophenoxy) biphenyl and 17 N, N-dimethylacetamide were added.
After charging 2.5 g, 20.71 g (0.095 mol) of pyromellitic dianhydride was added in portions at room temperature under a nitrogen atmosphere while paying attention to the rise in solution temperature, and the mixture was stirred at room temperature for about 20 hours. The polyamic acid thus obtained had an inherent viscosity of 0.58 dl / g.

To this polyamic acid solution, 345.1 g of N, N-dimethylacetamide was added, and while stirring, under a nitrogen atmosphere,
When heated to 0 ° C. and stirred at the same temperature for about 1 hour, yellow polyimide powder began to precipitate. Further, the mixture was stirred at the same temperature for 2 hours and then filtered to obtain a polyimide powder. After sludging this polyimide powder with methanol,
It was dried under reduced pressure for 4 hours to obtain 43.1 g (yield 80%) of polyimide powder.

The polyimide thus obtained had a melt viscosity of 4 × 10 ³ poise at 400 ° C. using a load of 100 kg and an orifice of 0.1 cm.

Example-4 In a container equipped with a stirrer, a reflux condenser and a nitrogen introducing tube, 4,4'-bis (3-aminophenoxy) biphenyl 3.68 g (0.01 mol) and pyromellitic anhydride 2.11 g (0.00
(97 mol) and m-cresol (52.1 g) were charged, and the mixture was heated in a nitrogen atmosphere while stirring and heated. At 135 ° C, a brown transparent homogeneous solution was formed. After heating to 150 ℃ and stirring, yellow polyimide powder began to precipitate in about 10 minutes. After stirring for 2 hours under heating,
Filtration gave a polyimide powder. The polyimide powder was washed with methanol and acetone and then dried under reduced pressure at 180 ° C. for 24 hours to obtain 4.62 g (yield 85.1%) of polyimide powder. The infrared absorption spectrum of the polyimide powder obtained here was similar to that shown in FIG.

〔The invention's effect〕

The present invention, in addition to the excellent heat resistance inherent in polyimide, has excellent processability, has a low water absorption rate, and also has excellent solvent resistance and alkali resistance, and provides a completely novel polyimide that can be used for multiple purposes. Is.

[Brief description of drawings]

FIG. 1 is an example of an infrared absorption spectrum diagram of the polyimide powder of the present invention, and FIG. 2 is a diagram showing the relationship between the melt viscosity and the shear rate of the polyimide powder of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akihiro Yamaguchi 1-13-24 Sasaki, Kamakura City (56) References JP-A-55-166622 (JP, A) JP-A-61-143433 (JP, A) JP-A-61-143435 (JP, A) JP-A-61-143478 (JP, A) JP-A-61-273953 (JP, A) JP-A-61-277921 (JP, A) JP-A-61-277923 (JP, A) Journal of Polymer Science 42 (7) pp.443-451.

Claims (1)

(57) [Claims] 1. A formula (I) Of the repeating unit represented by the formula (II) which is a precursor thereof. The logarithmic viscosity of polyamic acid consisting of repeating units represented by (N, N-dimethylacetamide solvent, concentration 0.5 g / 100 ml
Polyimide whose solvent, measured at 35 ° C) is 0.1 to 4.0 dl / g.