JP2540546B2 - Polyimide resin composition - Google Patents

Description

The present invention relates to a novel polyimide resin composition having excellent heat resistance, dimensional stability, mechanical strength and the like.

[Conventional technology]

Conventionally, a polyimide resin obtained by the reaction of tetracarboxylic dianhydride and diamine is excellent in electrical strength because it is excellent in mechanical strength, dimensional stability, flame retardancy, and electrical insulation in addition to its high heat resistance. It is widely used in fields such as electronic equipment, aerospace equipment, and transportation equipment, and is expected to be used in the fields where heat resistance is required.

Many of the polyimides developed so far have excellent properties, but they have excellent heat resistance but poor processability, and resins developed for the purpose of improving processability are inferior in heat resistance and solvent resistance. There were merits and demerits in performance.

The present inventors have defined a general formula (I) as a polyimide resin which can be further melt-molded and has excellent mechanical strength, thermal properties, electrical properties, solvent resistance and the like. (In the formula, R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group,
Represents a tetravalent group selected from the group consisting of a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which aromatic groups are connected to each other directly or by a bridging member. . ] A polyimide resin having a repeating unit represented by (JP-A-63-243132).

The above-mentioned polyimide resin is a novel heat-resistant resin having good physical properties peculiar to polyimide resin, and compared with ordinary engineering plastics represented by polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polysulfone, polyphenylene sulfide, etc. Although the heat resistance was far superior, the glass transition temperature was 220 to 290 ℃ and the heat distortion temperature was around 200 to 270 ℃, which was a problem in terms of heat resistance.

[Problems that the invention is trying to solve]

An object of the present invention is to obtain a polyimide resin composition having further improved heat resistance, dimensional stability, mechanical strength, etc. without impairing the moldability of the polyimide resin.

[Means for solving problems]

As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a polyimide resin composition comprising the polyimide resin and a specific amount of reinforcing fibers is effective, and completed the present invention.

That is, the present invention includes (1). Formula (A) (In the formula, R is C = C, It represents at least one tetravalent group selected from the group consisting of: ) A polyimide resin composition comprising 100 parts by weight of a polyimide resin having a repeating unit represented by and 5 to 100 parts by weight of a reinforcing fiber, (2). The polyimide resin composition according to the above item (1), wherein the reinforcing fibers are carbon fibers, (3). The polyimide resin composition according to the above item (1), wherein the reinforcing fibers are glass fibers, (4). The polyimide resin composition according to the above item (1), wherein the reinforcing fiber is potassium titanate fiber, and (5). The polyimide resin composition according to the item (1), wherein the reinforcing fiber is an aromatic polyamide fiber.

The polyimide resin used in the present invention has the formula (II) as a diamine component. A polyimide obtained by further dehydrating and cyclizing a polyamic acid obtained by reacting an ether diamine represented by the formula (1) with one or more tetracarboxylic dianhydrides.

Further, other diamines can be mixed and used within a range that does not impair various good physical properties of the polyimide resin used in the present invention. Examples of diamines that can be used as a mixture include, for example, metaphenylenediamine, paraphenylenediamine, orthophenylenediamine, aminobenzylamine, p-aminobenzylamine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,
3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide,
3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone,
4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,
4'-diaminobenzophenone, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4-
(3-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane,
1,2-bis [4- (3-aminophenoxy) phenyl]
Ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-amino) Phenoxy) phenyl] propane, 2,2-bis [4
-(3-Aminophenoxy) phenyl] butane, 2,2-
Bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2 -Bis [4- (4-aminophenoxy) phenyl] -1,1,1,
3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 4,4'-bis (3-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl , Bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aquinophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4- Aminophenoxy) phenyl] sulfide, bis [4- (3
-Aminophenoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, Bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aquinophenoxy) benzoyl] benzene, 1,3bis [4-
(3-aminophenoxy) benzoyl] benzene and the like can be mentioned.

The tetracarboxylic dianhydride used in this method is
Formula (III) (In the formula, R is the same as R in the above formula (A).) Is a tetracarboxylic dianhydride.

That is, as the tetracarboxylic dianhydride used, for example, ethylenetetracarboxylic dianhydride, cyclopentanecarboxylic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-benzophenone Tetracarboxylic acid dianhydride, 2,2 ', 3,3'-benzophenone tetracarboxylic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 2,2'3,3 ′ -Biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis ( 3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2, 3-dicarboxyphenyl) methane dianhydride, bis (3,4-dical Xyphenyl) methane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic Acid dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracene tetracarboxylic acid dianhydride Anhydride, 1,2,7,8-phenanthrenetetracarboxylic acid dianhydride, 4,4 '-(p-phenylenedioxy) diphthalic acid dianhydride, 4,4'-(m-phenylenedioxy) diphthalate An acid dianhydride may be used.

These tetracarboxylic dianhydrides are used alone or in combination of two or more.

The reinforcing fibers used in the present invention are generally known inorganic or organic fibers such as carbon fibers, glass fibers, potassium titanate fibers, aromatic polyamide fibers, ceramic fibers and silicon carbide fibers.

As the carbon fiber, a fiber of high elasticity and high strength obtained by carbonizing polyacrylonitrile, petroleum pitch or the like as a main raw material can be used. Further, a carbon fiber having an appropriate diameter and an appropriate aspect ratio (ratio of length / diameter) is used in view of the reinforcing effect and the mixing property of the carbon fiber, and the diameter of the carbon fiber is usually 5 to 20 μ, particularly 8 to 15 μ. Aspect ratio is preferable, and aspect ratio is 1 to 600, especially 100 from the viewpoint of mixability and reinforcing effect.
It is preferably about 350. If the aspect ratio is small, there is no reinforcing effect, and if the aspect ratio is large, the mixing property is poor, and a good molded product cannot be obtained. Further, the surface of the carbon fiber is treated with various treatment agents such as epoxy oil, polyimide resin,
Those treated with a polyamide resin, a polycarbonate resin, a polyacetal resin or the like, or those using a known surface treatment agent depending on the purpose can also be used.

The glass fiber is made by thinning molten glass by various methods and quenching it into a thin fiber with a predetermined diameter. Single fibers are bundled with a sizing agent into a strand, and the strands are uniformly drawn and bundled. You can use roving etc. In addition, the glass fiber may be treated with a silane coupling agent such as aminosilane or epoxysilane, chromic chloride, or other surface-treating agent according to the purpose in order to have affinity with the base resin of the present invention. .

The length of glass fiber has a great influence on the physical properties of the obtained molded product and the workability at the time of manufacturing the molded product. In general, as the glass fiber length increases, the physical properties of the molded article improve, but conversely, the workability during the production of the molded article deteriorates. Therefore, the length of the glass fiber in the present invention is 0.1 to 6 mm, preferably 0.3 to 4 mm.
Those in the range of are preferable because both the physical properties and workability of the molded product are well balanced.

High strength fiber (whisker) for potassium titanate fiber
The chemical composition is K ₂ O ・ 6TiO ₂ , 6TiO ₂・ 1/2
It is a needle-like crystal based on H ₂ O and has a typical melting point of 1300 to 1
350 ℃ can be used. The average fiber length is 5 to 50 μm,
The average fiber diameter is 0.05 to 1.0 μm, and the average fiber length is preferably 20 to 30 μm and the average fiber diameter is preferably 0.1 to 0.3 μm. The potassium titanate fiber can be usually used without any treatment, but in order to have affinity with the base resin of the present invention, silane coupling agents such as aminosilane and epoxysilane, chromic chloride, and other surface treatment agents depending on the purpose. Those processed in can also be used.

As the aromatic polyamide fibers, for example, those having the following structural formulas as a typical example, and at least one kind or a mixture of two or more kinds thereof is used.

(I) In addition, aromatic polyamide fibers having various skeletons depending on the ortho, meta, and para isomer structures can be used in the same manner. Among them, the para-para-bonds of (1) have a high softening point and melting point and are used as heat-resistant organic fibers. This is the most preferable example in the present invention.

The above carbon fibers, glass fibers, potassium titanate fibers, and reinforcing fibers such as aromatic polyamide fibers are 5 to 100 parts by weight, preferably 10 to 10 parts by weight, based on 100 parts by weight of the polyimide resin.
50 parts by weight can be used. If it is 5 parts by weight or less, the reinforcing effect, which is a feature of the present invention, will not be obtained, and if it is used in an amount of 100 parts by weight or more, it will be a problem in terms of physical properties or moldability.

The polyimide resin composition according to the present invention can be produced by a generally known method, but the following method is particularly preferable.

(1) Polyimide powder and reinforcing fibers are premixed by using a mortar, Henschel mixer, drum blender, tumbler blender, ball mill, ribbon blender, etc., and then kneaded with a commonly known melt mixer, hot roll, etc., and then pelletized. Or pulverize.

(2) Polyimide powder is dissolved or suspended in an organic solvent in advance, and this solution or suspension is impregnated with reinforcing fibers. After that, the solvent is removed in a hot air oven, and then pelletized or powdered. In this case, as the solvent, for example, N, N-dimethylformamide, N, N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxy is used. Ethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy)
Ethane, bis {2- (5-methoxyethoxy) ethyl}
Ether, tetrahydrofuran, 1,3-dioxane, 1,4
-Dioxane, pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethylurea, hexamethylphosphoramide, phenol, m-cresol, p
-Cresol, o-cresol, anisole, p-chlorophenol and the like. These organic solvents may be used alone or in combination of two or more.

(3) After impregnating the reinforcing fibers in a solution prepared by dissolving the polyamic acid, which is the precursor of the polyimide of the present invention, in the organic solvent, it is heat-treated at 100 to 400 ° C, or a commonly used imidizing agent. After chemical imidization using, the solvent is removed to obtain pellets or powder.

Incidentally, for the composition of the present invention, as long as the object of the present invention is not impaired, an antioxidant and a heat stabilizer, an ultraviolet absorber, a flame retardant auxiliary, an antistatic agent, a lubricant, a usual coloring agent, etc. One or more additives can be added.

Other thermoplastic resins (eg, polyethylene, polypropylene, polyamide, polycarbonate, polyarylate, polysulfone, polyethersulfone, polyetherketone, modified polyphenylene oxide, polyphenylene sulphite, polyamideimide, polyetherimide, etc.), thermosetting It is also possible to add a suitable amount of a functional resin (for example, phenol resin, epoxy resin, etc.) or a filler such as clay, mica, silica, graphite, glass beads, alumina, calcium carbonate, etc. depending on the purpose.

The polyimide resin composition of the present invention is molded by a known molding method such as an injection molding method, an extrusion molding method, a compression molding method, a rotational molding method, and put into practical use.

〔Example〕

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

Synthesis Example In a two flask equipped with a stirrer, a reflux condenser, and a thermometer, 309 g of 3-nitrophenoxybenzoyl chloride (1.
11 mol), diphenyl ether 85.5 g (0.502 mol), 1,
Charge 2-dichloroethane 1.

The mixture is stirred so that the temperature does not exceed 40 ° C., and 198 g (1.49 mol) of anhydrous aluminum chloride is added portionwise over 1.5 hours. Five
After stirring at 5-60 ° C for 11 hours, cool and discharge into water 2.

The organic layer to be separated is washed with a 5% aqueous solution of NaOH and the solvent is distilled off under reduced pressure to obtain a crude dinitro compound of the following formula as a tan oil. Yield 312. (Yield 95%) This crude dinitro compound was added to 2-methoxyethanol 1.5
Into a catalytic reduction flask equipped with a reflux condenser, thermometer, and stirrer, 16.5 g of 5% Pd / C is added. When hydrogen is introduced at 30 to 35 ° C with vigorous stirring, the absorption of hydrogen stops in 7.5 hours. The crystals obtained are filtered hot to remove P
When d / C is removed and cooled, pale yellow crystals are precipitated. After filtration, washing, and drying, the desired aromatic diamine was obtained as pale yellow crystals.

Yield 253 (yield 85%) The crude crystals thus obtained were recrystallized from 2-methoxyethanol to obtain a pure product.

Light yellow crystal mp 169.5-171.5 ℃ Elemental analysis CHN Calcd (%) 77.01 4.76 4.73 Obsd (%) 76.86 4.59 4.65 IR (KBr disk cm ^-1 ): 3380 (Amino group) 1630 (Carbonyl group) 1220 (Ether bond) ) MS (FD method): 592 (M ⁺ ), 296 (M ⁺ / 2) [Examples] The present invention will be described in more detail below with reference to Production Examples, Examples, and Comparative Examples.

The values of% and parts shown in the following examples mean% by weight and parts by weight, respectively, unless otherwise specified.

Production Example 1 In a container equipped with a stirrer, a reflux condenser and a nitrogen introducing tube, 4,4'-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether (59.2 Kg, 100 mol) and N, N-
Dimethylacetamide (186.9 Kg) was charged, and 20.9 Kg (96 mol) of pyromellitic dianhydride was added 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 24 hours to obtain a polyamic acid solution. . The logarithmic viscosity of this polyamic acid was 0.69 dl / g. (Measurement temperature is 35 ℃, N, N-
Dimethylacetamide solvent, concentration 0.5 g / dl, values shown below were all under the same conditions. ) To this solution, 535 Kg of N, N-dimethylacetamide was further added, and 40.8 Kg (40
0 mol) of triethylamine and 60.3 Kg (600 mol) of acetic anhydride were added dropwise. After stirring at room temperature for about 24 hours, add water.
The solution was discharged into 2500 under vigorous stirring, the precipitate was filtered off, washed with methanol, and dried under reduced pressure at 150 ° C for 24 hours to obtain 72.5 kg (yield about 97.0%) of a pale yellow polyimide powder. Got The glass transition temperature of this polyimide powder is 227 ° C.
(Measured by DSC method), 5% weight loss temperature is 540 ℃
(Measured by the DTA-TG method).

 The measurement results of elemental analysis are as follows.

Production Examples 2 to 5 Various acid dianhydrides shown in Table 1 were used in place of the pyromellitic dianhydride used in Production Example 1, and polymerization was performed in the same manner as in Production Example 1 to obtain a polyimide powder. It was In Table 1, polyimide resin synthesis conditions, logarithmic viscosity of polyamic acid,
The glass transition temperature, elemental analysis value and 5 %% thermal decomposition temperature of the obtained polyimide powder are shown.

Examples 1 to 5, Comparative Examples 1 to 2 Polyimide powders obtained in Production Examples 1 to 5, each having an average diameter of 12 μm, a length of 3 mm, and an aspect ratio of 250 per 100 parts by weight.
Table 2 shows the carbon fibers (trade name: Torayca) manufactured by Toray
After adding the amount shown in, and mixing with a drum blender mixer (manufactured by Kawata Manufacturing Co., Ltd.), 400 with a single screw extruder with a diameter of 30 mm.
After melt-kneading at a temperature of ° C, the strand was air-cooled and cut to obtain pellets.

The obtained pellets were injection-molded with an injection molding machine (Argburg Allround A-220, manufactured by Arburg, West Germany) (injection pressure 500 Kg / cm ² , cylinder temperature 400 ° C, mold temperature).
180 ° C.) Tensile test pieces, bending test pieces, Izod impact strength test pieces, and mold shrinkage measurement test pieces were obtained.

Tensile test ASTM D-638, bending test ASTM D-790
The Izod impact strength test was conducted according to ASTM D-256, the heat distortion temperature was conducted according to ASTM D-684, and the molding shrinkage was conducted according to ASTM D-955. The results are shown in Table 2.

Examples 6 to 10 and Comparative Examples 3 to 4 Polyimide powders obtained in Production Examples 1 to 5, glass fibers treated with silane, having a fiber length of 3 mm and a fiber diameter of 13 μm per 100 parts by weight (Nitto Boseki Co., Ltd. Manufactured by CS-3PE-476S) in an amount shown in Table 3 and mixed by a drum blender mixer (manufactured by Kawata Manufacturing Co., Ltd.), and then a single screw extruder having a diameter of 30 mm.
After melt-kneading at a temperature of 310 to 350 ° C., the strand was air-cooled and cut to obtain pellets.

Various test pieces were prepared from the obtained pellets in the same manner as in Example 1 and each physical property was measured. The results are shown in Table 3.

Examples 11 to 15 and Comparative Examples 5 to 6 With respect to 100 parts by weight of each of the polyimide powders obtained in Production Examples 1 to 5, potassium titanate fibers having a cross-sectional diameter of 0.2 μm and an average fiber length of 20 μm (manufactured by Otsuka Chemical Co., Ltd.) Tismo-D) in an amount shown in Table 4 and mixed in a drum blender mixer (manufactured by Kawata Manufacturing Co., Ltd.), and then a single screw extruder having a diameter of 30 mm.
After melt-kneading at a temperature of 310 to 350 ° C., the strand was air-cooled and cut to obtain pellets.

Various test pieces were prepared from the obtained pellets in the same manner as in Example 1 and each physical property was measured. The results are shown in Table 4.

Examples 16 to 20 and Comparative Examples 7 to 8 Polyimide powders obtained in Production Examples 1 to 5, and 100 parts by weight of each, were mixed with aromatic polyamide fibers having an average fiber length of 3 mm (manufactured by DuPont, trade name Kevlar). The amounts shown in Table 5 were added, mixed in a drum blender mixer (Kawata Manufacturing Co., Ltd.), melt-kneaded at a temperature of 310 to 350 ° C. with a single screw extruder having a diameter of 30 mm, and then the strand was air-cooled and cut. Pellets were obtained.

Various test pieces were prepared from the obtained pellets in the same manner as in Example 1 and each physical property was measured. In addition, the fluidity test during molding processing is injection molding conditions (injection pressure 500 Kg / cm ² , cylinder temperature 400 ° C, mold temperature 180 ° C). At 10 mm in width and 2.0 mm in wall thickness, the flow length by spiral flow was measured and determined. The results are shown in Table 4.

〔The invention's effect〕

The heat-resistant resin composition of the present invention is excellent in heat resistance, dimensional stability, mechanical strength and the like, and can be melt-molded, for electric / electronic equipment, for aerospace equipment, for transportation equipment,
It can be used in a wide range of industrial fields for office equipment and general industrial equipment.

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Claims (5)

(57) [Claims] 1. Formula (A) (In the formula, R is C = C, It represents at least one tetravalent group selected from the group consisting of: ) A polyimide resin composition comprising 100 parts by weight of a polyimide resin having a repeating unit represented by and 5 to 100 parts by weight of reinforcing fibers. 2. The polyimide resin composition according to claim 1, wherein the reinforcing fibers are carbon fibers. 3. The polyimide resin composition according to claim 1, wherein the reinforcing fibers are glass fibers. 4. The polyimide resin composition according to claim 1, wherein the reinforcing fibers are potassium titanate fibers. 5. The polyimide resin composition according to claim 1, wherein the reinforcing fibers are aromatic polyamide fibers.