JP2511987B2 - Aromatic polyimide polymer molded article manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a novel aromatic polyimide polymer molded article having high strength, high elastic modulus and extremely excellent heat resistance.

(Problems to be solved by conventional techniques and inventions) The wholly aromatic polyimide has the highest heat resistance among organic polymers, and it has already been put to practical use in molded products such as films by taking advantage of its characteristics. However, the mechanical properties of those existing products are very common, and the strength and elastic modulus are never high. As an example of obtaining a high-modulus polyimide molded product, as a fiber, a solution of a polyamic acid composed of a rigid aromatic diamine and a specific aromatic tetracarboxylic acid dianhydride is mixed-spun and stretched in Japanese Patent Publication No. 57-37687. After that, a method of heating to cyclize to an imide group is shown, but the mechanical properties of the obtained fiber are not very excellent. In addition, JP 60
-65112, the diamine component is 3,3'-dimethylbenzidine, and the acid anhydride component is pyromellitic dianhydride (A) and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride. High strength consisting of a mixture of a certain ratio of the product (B)
High modulus fibers are disclosed. In this publication, a solution obtained by dissolving the polyimide in a phenolic solvent is used as an undiluted solution, mixed spinning is performed in an ethanol coagulation bath, and then hot drawing is performed to obtain a polyimide fiber, but there are the following problems. That is,
Since 3,3'-dimethylbenzidine is used as the diamine component, the produced polyimide is a nuclear methyl substitution product, and the excellent heat resistance inherent to the polyimide is considerably impaired.

Therefore, a polyimide molded product having high strength and high elastic modulus and extremely excellent heat resistance is particularly desirable. As a result of intensive studies aimed at a polyimide molded product having the above-mentioned various properties, the present inventors have found that an aromatic polyimide copolymer composed of a mixture of a specific aromatic diamine or a mixture thereof and an aromatic tetracarboxylic dianhydride is The inventors have found that they are suitable for the purpose and arrived at the present invention.

(Means for Solving the Problem) That is, the present invention is based on the general formula (1) (Wherein R ₁ represents a tetravalent aromatic group) and the repeating unit represented by the general formula (2) Is a method for producing an aromatic polyimide polymer molded article, in which a polyimide copolymer mainly comprising a repeating unit represented by or a polyamic acid polymer which is a precursor thereof is stretched.

The polyimide used in the present invention mainly has repeating units represented by the general formulas (1) and (2). These repeating units must be present in an amount of 50 mol% or more, preferably 70% mol or more, more preferably 90% or more, based on the total repeating units.

In the copolymer having repeating units represented by the general formulas (1) and (2), the molar ratio of repeating units (1) /
The value of (2) is preferably 10/90 or more. (1)
When / (2) does not exceed 10/90 and the proportion of the repeating unit represented by the general formula (1) is small, an aromatic polyimide molded article having poor strength and elastic modulus is obtained.

In the general formula (1) or (2), R ₁ is an aromatic group having a bond on the carbon atom forming the aromatic ring. Etc. can be given.

The aromatic polyimide is usually obtained from its precursor polyamic acid, but it may be one prepared by another method. Polyamic acid is usually represented by the general formula (3) Aromatic tetracarboxylic dianhydride represented by and para-phenylenediami, aromatic diamine components such as diaminophenyl ether are used in a substantially polar amount to obtain by polymerizing in an organic polar solvent. May be.

When obtaining the copolymer having repeating units of the general formulas (1) and (2) of the present invention, the polyamic acid can be produced by various methods as described below.

(A) A mixture of paraphenylenediamine, diaminodiphenyl ether, and optionally other diamine, and aromatic tetracarboxylic dianhydride (3) are reacted in a substantially equimolar organic polar solvent to obtain a random copolymer. Copolymerization method.

(B) An aromatic tetracarboxylic dianhydride (3) and an aromatic diamine of either paraphenylenediamine or diaminodiphenyl ether are used so that the aromatic tetracarboxylic dianhydride (3) has an excess equivalent amount. , And react in an organic polar solvent to obtain a prepolymer having acid anhydride groups at both ends. Then, the other aromatic diamine compound is added thereto so that the wholly aromatic diamine is substantially equimolar to the aromatic tetracarboxylic dianhydride (3) and polymerized, and then the general formula (1) or ( A copolymerization method for obtaining a copolymer having a substantially constant length of a segment in which at least one monomer unit of 2) is continuous.

(C) Aromatic tetracarboxylic dianhydride (3) and either aromatic diamine of paraphenylenediamine or diaminodiphenyl ether are used so that the aromatic tetracarboxylic dianhydride (3) is in an excessively small amount. , And react in an organic polar solvent to obtain a prepolymer having amino groups at both ends. Subsequently, after the additional addition of the other aromatic diamine compound, so as to be substantially equimolar with the total diamine component, the insufficient amount of aromatic tetracarboxylic dianhydride is added and reacted to form a block copolymer. Copolymerization method to obtain.

The polyamic acid may be synthesized using any of the above methods and other methods. Further, it can be obtained by mixing different polyamic acid solutions. When the method (B) is used among the above methods, an excellent one in terms of tensile properties such as elongation and tensile strength can be obtained.

Specific examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and 3,3 ′, 4,4′-benzophenone tetra. Examples thereof include carboxylic acid dianhydride and naphthalene-1,2,5,6-dianhydride. You may use these individually or in combination of 2 or more types.

As the aromatic diamine component, 4,4'-diaminodiphenyl ether and a polyvalent amine other than para-phenylenediamine may be partially used. Examples of such amines include:
4,4'-bis (4-aminophenoxy) biphenyl, 4,
4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (2 Aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4- Bis (4-aminophenyl) benzene, bis [4- (4-aminophenoxy) phenyl]
Ether, 4,4'-diaminodiphenylmethane, bis (3-ethyl-4-aminophenyl) methane, bis (3
-Methyl-4-aminophenyl) methane, bis (3-chloro-4-aminophenyl) methane, 3,3-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 2,2 ', 5,5'- Tetrachloro-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfide, 3,3 '
-Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane,
4,4'-diaminobiphenyl, 4,4'-diaminooctafluorobiphenyl, 2,4'-diaminotoluene, metaphenylenediamine, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2, 2-bis [4- (4-
Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) propane, 2,2-
Bis (4-aminophenyl) hexafluoropropane,
2,2-bis (3-hydroxy-4-aminophenyl) propane, 2,2-bis (3-hydroxy-4-aminophenyl) hexafluoropropane, 9,9-bis (4-aminophenyl) -10- Examples thereof include hydro-anthracene, orthotolidine sulfone, 3,3 ', 4,4'-biphenyltetraamine and 3,3', 4,4'-tetraaminodiphenyl ether.

Examples of the organic polar solvent used in the reaction for producing the polyamic acid here include, for example, dimethyl sulfoxide, sulfoxide-based solvents such as diethyl sulfoxide, N, N-dimethylformamide, N, N-formaldehyde solvents such as diethylformamide, N, N-dimethylacetamide,
Acetamide-based solvents such as N, N-diethylacetamide, pyrrolidone-based solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-,
Phenolic solvents such as m- or p-cresol, xylenol, halogenated phenol, and catechol, hexamethylphosphoramide, γ-butyrolactone and the like can be mentioned, and it is desirable to use these alone or as a mixture, Furthermore, it is possible to use aromatic hydrocarbons such as xylene and toluene. Also,
It is desirable from the viewpoint of handling that the polyamide is dissolved in the organic polar solvent in an amount of 5 to 40% by weight, preferably 10 to 30% by weight.

In order to obtain the aromatic polyimide polymer of the present invention from this aromatic polyamic acid solution, either a thermal method of thermally dehydrating or a chemical method using a dehydrating agent may be used. The resulting polyimide polymer is preferable because it has excellent tensile properties such as elongation and tensile strength, and dimensional stability such as linear expansion coefficient. The aromatic polyimide polymer molded product of the present invention is a stretched product, but the stretching may be performed at the stage of the molded product such as a polyamic acid polymer film or fiber, or at the stage of the polyimide polymer molded product. May be performed at any time, or may be performed at an intermediate step. The stretching ratio is preferably 0.5 to 3.0, and the stretching temperature is in the range of 0 ° C to 60 ° C. Two methods are illustrated below for the imidization method and the stretching method.

(A) The polyamic acid polymer solution or a solution obtained by adding a dehydrating agent in a stoichiometric amount or more and a catalytic amount of a tertiary amine to the solution is cast or coated on a drum or an endless belt to form a film, The membrane is dried at a temperature below 150 ° C for about 5 to 90 minutes to obtain a self-supporting polyimide acid membrane. Next, this is peeled from the support, the end portion is fixed, and then stretching is performed. Stretching temperature is 50-150 ° C and stretching ratio is 0.5-3.0
Is preferred. Thereafter, it is imidized by gradually heating to about 100 to 500 ° C., and after cooling it is removed to obtain the molded aromatic polyimide polymer product of the present invention.

(B) The aromatic pomiamic acid polymer solution, or a solution prepared by adding a stoichiometric or more stoichiometric dehydrating agent and a catalytic amount of a tertiary amine to the solution is cast or coated on a drum or an endless belt. A film is formed, and the film is dried at a temperature of 150 ° C. or lower for about 5 to 90 minutes to obtain a self-supporting polyamic acid film. Then, after peeling it from the support and fixing the end, it is imidized by gradually heating to about 100 to 500 ° C., and then stretched at a temperature of 350 ° C. or higher, preferably 400 ° C. or higher, or 350 ° C. Stretching is carried out at a temperature not exceeding 100 ° C., followed by heating to 400 ° C. or higher, cooling and removal from this to obtain the aromatic polyimide polymer molded product of the present invention. The stretching ratio is preferably 0.5 to 3.0.

Examples of the dehydrating agent here include aliphatic acid anhydrides such as acetic anhydride, aromatic acid anhydrides, and the like. The catalyst may be, for example, an aliphatic tertiary such as triethylamine.
Examples thereof include tertiary amines, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine, picoline, and isoquinoline.

The stretched molded product of the polyimide copolymer having the general formulas (1) and (2) of the present invention as a repeating unit has significantly improved strength and elastic modulus as compared with a molded product which is not stretched. The degree of this improvement is very remarkable as compared with the case of the polyimide having only (2) as a repeating unit. Further, the stretch-molded product of the copolymer polyimide having the general formulas (1) and (2) as repeating units of the present invention improves not only the physical properties in the stretching direction but also the physical properties in the stretching direction and the vertical direction in the case of uniaxial stretching. There is a feature that can be done.

The present invention is effective not only in the case of a film but also in the case of a fiber. The obtained film can be used as a base film for magnetic recording and the like, and the fiber can be used as heat resistant reinforcing fiber and the like.

(Examples) Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

In the examples, ODA is 4,4'-diaminodiphenyl ether, p-PDA is paraphenylenediamine, PMDA is pyromellitic dianhydride, BPDA is 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, DMAc. Represents dimethylacetamide.

Comparative Example 1 ODA and PMDA were polymerized in DMAc to obtain a 15% by weight polyamic acid solution.

Cast the polyamic acid solution onto a glass plate and coat it at approximately 100 ° C.
After drying for about 60 minutes, peel the polyamic acid coating film from the glass plate, fix the coating film to the support frame, and then about 100 ° C for about 30 minutes, about 200 ° C for about 60 minutes, about 300 ° C for about 30 minutes. After heating for 60 minutes, dehydration ring closure drying and stretching at 450 ° C., a polyimide film of about 20 microns was obtained.

 Table 1 shows the properties and the stretching ratio of the obtained film.

Example 1 BPDA using ODA and p-PDA at a molar ratio of 10:90 in DMAc.
Polymerization was carried out to obtain a 15% by weight polyamic acid copolymer solution.

Using this polyamic acid solution, a polyimide copolymer film of about 20 microns was obtained in the same manner as in Comparative Example 1. Table 1 shows the properties and stretching ratio of this film.

Example 2 PMDA in DMAc using ODA and p-PDA at a molar ratio of 67:33.
Polymerization was carried out to obtain a 15% by weight polyamic acid copolymer solution. Using this polyamic acid solution, a polyimide copolymer film of about 20 microns was obtained in the same manner as in Comparative Example 1. Table 1 shows the properties and stretching ratio of this film.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 62-77921 (JP, A) JP 60-97834 (JP, A) JP 59-157319 (JP, A)

Claims (2)

(57) [Claims] 1. General formula (1): [In the formula, R ₁ represents a tetravalent aromatic group. ] And the repeating unit represented by the general formula (2): [In the formula, R ₁ is the same as above. ] The manufacturing method of the aromatic polyimide polymer molded item which has the process of extending | stretching the polyamic-acid polymer which is a polyimide copolymer or its precursor which has the repeating unit represented by these. 2. R ₁ is The method for producing an aromatic polyimide polymer molded article according to claim 1, which is at least one of the above.