JP2006299079A - Method for manufacturing polyimide precursor molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyimide precursor molded product useful for manufacturing a polyimide molding article excellent in heat resistance and mechanical property. <P>SOLUTION: This method for manufacturing the polyimide precursor molded product comprises a step of molding a dope for molding containing an ester of a polyamic acid, as a repeating unit, represented by formula (I) (wherein R<SB>1</SB>is selected from a 1-18C aliphatic alcohol residue, a 7-18 aromatic alcohol residue and a 6-18 alicyclic alcohol, and may be same or different, and Ar<SB>1</SB>is a para-orientational divalent aromatic group) as a main component, a step of immersing a resultant molded product in a solidifying liquid and making a solidified product, and a step of immersing the solidified product in a swelling agent and followed by extending it. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a polyimide precursor molded article useful for producing a polyimide molded article having excellent heat resistance and mechanical properties.

Polyimide has been widely developed due to its high heat resistance and mechanical properties. In particular, wholly aromatic polyimides are expected to exhibit particularly high heat resistance and mechanical properties due to their rigid structure.
However, since the wholly aromatic polyimide is infusible and insoluble, it is difficult to mold it in the polyimide state.

  Therefore, in order to avoid this problem, after performing molding or orientation operation in the state of polyamic acid which is a reaction product of a diamine component and an acid anhydride, molding is performed at the polyimide precursor stage. There is a method of obtaining a polyimide molded body by converting. However, polyamic acid is generally very easily hydrolyzed and has a problem that its molecular weight is lowered during molding and thermal imidization.

  In order to solve this problem, studies have been made on polyimide fibers or films using a polyamic acid ester as a polyimide precursor. For example, it is described that a polymer solution composed of polyamic acid ester, hexethylphosphoric triamide and benzene is solidified with methanol and then stretched to obtain polyamic acid ester fibers (Non-patent Document 1). However, the solvent used to prepare the polymer solution is harmful to the human body, and because alcohol is used to solidify, complicated equipment is required. A method for producing a precursor molding has been desired.

Am. Chem. Soc. Polym. Prepn. , 34 (1), 746 (1993)

  The main object of the present invention is to solve the problems of the prior art as described above, and suppress precursors such as highly oriented polyimide fibers or films that can suppress the decrease in molecular weight without adversely affecting the physical properties and structure of the molded product. It is providing the manufacturing method of a body molding.

  As a result of intensive studies to achieve the above object, the present inventor performed a swelling treatment using a swelling agent composed of a mixed solution of an amide solvent and water on the molded product after solidification, and subsequently It has been discovered that a desired molded product can be obtained by a simple process by stretching, and the present invention has been derived.

That is, the present invention is as follows.
1. Formula (I)
(I)
(R ₁ is selected from an aliphatic alcohol residue having 1 to 18 carbon atoms, an aromatic alcohol residue having 7 to 18 carbon atoms, and an alicyclic alcohol residue having 6 to 18 carbon atoms. Ar ₁ is a divalent aromatic group represented by any of the following:

After forming a molding dope containing a polyamic acid ester whose main component is a repeating unit represented by the formula, the obtained molding is immersed in a coagulation liquid to obtain a coagulation, and then the coagulation is swollen. A method for producing a polyimide precursor molded product, wherein the polyimide precursor molded product is dipped in, and then stretched.
2. The method for producing a polyimide precursor molded product as described above, wherein the coagulation liquid is a mixed liquid composed of water and an amide solvent, and the content of water in the mixed liquid is 50% by weight or more.
3. The polyimide precursor molding as described above, wherein the amide solvent is at least one selected from the group consisting of N-methyl-2-pyrrolidone, N, N-dimethylacetamide and N, N dimethylformamide Manufacturing method.
4). A polyimide precursor molded product obtained by any of the above methods.
5. A method for producing a polyimide molded product, comprising heat-treating a polyimide precursor molded product obtained by any one of the above methods.
6). It is the polyimide molding obtained by said method.

According to the present invention, a highly oriented polyimide precursor molding can be obtained.
Moreover, the polyimide precursor molding obtained by this invention is heat-processed, molecular weight fall is suppressed and the highly oriented polyimide molding can be obtained.

The polymer comprising the repeating unit of the above formula (I) is composed of (a) an aromatic diamine compound and (b) the following formula:
(R ₁ has the same definition as in formula (I).)
It is manufactured by performing solution polymerization using the acid chloride represented by these.

As the (a) aromatic diamine compound used in the present invention,
And each aromatic ring may be substituted with a nucleus. These aromatic diamine compound groups are referred to as para-oriented aromatic diamines. Above all
Is preferred.

  Examples of the aromatic diamine component different from the para-oriented aromatic diamine include m-phenylenediamine, 1,4-diaminonaphthalene, 1,8-diaminonaphthalene, 2,7-diaminonaphthalene, and 2,6-diaminoanthracene. 2,7-diaminoanthracene, 1,8-diaminoanthracene, 2,4-diaminotoluene, 2,5-diamino (m-xylene), 2,5-diaminopyridine, 2,6-diaminopyridine, 3,5 -Diaminopyridine, 2,4-diaminotoluenebenzidine, 3,3'-diaminobiphenyl, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-diamino Benzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenyl amine 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylsulfone 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl thioether, 4,4 ′ -Diamino-3,3 ', 5,5'-tetramethyldiphenyl ether, 4,4'-diamino-3,3', 5,5'-tetraethyldiphenyl ether, 4,4'-diamino-3,3 ', 5 , 5'-tetramethyldiphenylmethane, 1,3-bis (3-amino Enoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,6-bis (3 -Aminophenoxy) pyridine, 1,4-bis (3-aminophenylsulfonyl) benzene, 1,4-bis (4-aminophenylsulfonyl) benzene, 1,4-bis (3-aminophenylthioether) benzene, 1, 4-bis (4-aminophenylthioether) benzene, 4,4′-bis (3-aminophenoxy) diphenylsulfone, 4,4′-bis (4-aminophenoxy) diphenylsulfone, bis (4-aminophenyl) aminebis (4-Aminophenyl) -N-methylamine bis (4-aminophenyl) -N-phenylamine bis (4-aminophenyl) phosphine oxide, 1,1-bis (3-aminophenyl) ethane, 1,1-bis (4-aminophenyl) ethane, 2,2-bis (3-aminophenyl) propane, 2, 2-bis (4-aminophenyl) propane, 2,2-bis (4-amino-3,5-dimethylphenyl) propane, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3 -Aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] methane, Bis [3-methyl-4- (4-aminophenoxy) phenyl] methane, bis [3-chloro-4- (4-aminophenoxy) phenyl] methane Bis [3,5-dimethyl-4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [3-methyl-4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [3-chloro-4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [3,5-dimethyl-4- (4-amino) Phenoxy) phenyl] ethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3-methyl-4- (4-aminophenoxy) phenyl] propane, 2,2- Bis [3-chloro-4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3,5-dimethyl-4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4 Aminophenoxy) phenyl] butane, 2,2-bis [3-methyl-4- (4-aminophenoxy) phenyl] butane, 2,2-bis [3,5-dimethyl-4- (4-aminophenoxy) phenyl ] Butane, 2,2-bis [3,5-dibromo-4- (4-aminophenoxy) phenyl] butane, 1,1,1,3,3,3-hexafluoro-2,2-bis (4- Aminophenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2-bis [3-methyl-4- (4-aminophenoxy) phenyl] propane and the like and their halogen atoms or alkyl groups Aromatic nucleus substitution product by

  The diamine component consists of a para-oriented aromatic diamine alone or a combination of a para-oriented aromatic diamine and a different aromatic diamine as described above. In the latter combination, the para-oriented aromatic diamine is based on the total diamine component in a proportion of more than 80 mol%, preferably more than 90 mol%, ie less than 20 mol%, preferably 10 It consists of less than mol%.

  Moreover, the acid chloride of (b) can be manufactured using a well-known method. For example, (1) pyromellitic diester is synthesized by reacting pyromellitic dianhydride with alcohol. As the alcohol used here, an aliphatic alcohol having 1 to 18 carbon atoms, an aromatic alcohol having 6 to 18 carbon atoms, or an alicyclic alcohol having 6 to 18 carbon atoms is used. To 12 aliphatic alcohols and alicyclic alcohols having 6 to 12 carbon atoms are preferred, and primary or secondary alcohols are particularly preferred. This reaction may be performed by simply reacting pyromellitic dianhydride in alcohol at room temperature to reflux temperature. However, at this time, it is preferable to reduce the moisture as much as possible to increase the yield. (2) Oxalyl chloride, thionyl chloride, etc. are added to the pyromellitic acid diester thus obtained to make carboxylic acid chloride, and (b) can be obtained by recrystallization.

  The solvent used for the polymerization is not particularly limited, but dissolves the raw material monomers (a) and (b) as described above and is substantially nonreactive with them, and preferably has an intrinsic viscosity of at least 1.0. As long as it is possible to obtain a polymer of 1.2 or more, more preferably any solvent can be used. For example, N, N, N ′, N′-tetramethylurea (TMU), N, N-dimethylacetamide (DMAC), N, N-diethylacetamide (DEAC), N, N-dimethylpropionamide (DMPR), N, N-dimethylbutyramide (NMBA), N, N-dimethylisobutyramide (NMIB), N-methylpyrrolidone-2 (NMP), N-ethylpyrrolidone-2 (NEP), N-methylcaprolactam (NMC), N, N-dimethylmethoxyacetamide, N-acetylpyrrolidine (NAPR), N-acetylpiperidine, N-methylpiperidone-2 (NMPD), N, N'-dimethylethyleneurea, N, N'-dimethylpropyleneurea, N, Amido solvents such as N, N ', N'-tetramethylmalonamide, N-acetylpyrrolidone, phenols such as p-chlorophenol, phenol, m-cresol, p-cresol, 2,4-dichlorophenol It can be mentioned system solvent or a mixture thereof.

  In this case, in order to increase the solubility, an appropriate amount of a known inorganic salt may be added before, during or at the end of polymerization. Examples of such inorganic salts include lithium chloride and calcium chloride.

  The polyamic acid ester can be produced in the same manner as in the usual solution polymerization method of polyamide in the above-mentioned solvent obtained by dehydrating the monomers (a) and (b). The reaction temperature at this time is 80 ° C. or less, preferably 60 ° C. or less. This is because an imidization reaction may occur if the temperature is too high. The concentration at this time is preferably about 1 to 20 wt% as the monomer concentration.

In the present invention, it is also possible to use trialkylsilyl chloride for the purpose of increasing the degree of polymerization of the polymer.
Further, when producing the polyamic acid ester, the molar ratio of these (a) aromatic diamine compound and (b) acid chloride is preferably 0.90 to 1.10, more preferably 0.95 to 1.05. And preferably used.

  The terminal of polyamic acid ester can also be sealed. In the case of sealing with an end-capping agent, examples of the end-capping agent include phthalic acid chloride and substituted products thereof, and examples of the amine component include aniline and substituted products thereof.

  In the reaction of acid chlorides and diamines that are generally used, aliphatic or aromatic amines or quaternary ammonium salts can be used in combination in order to capture the acid such as hydrogen chloride that is produced.

  As a method for obtaining a molding dope containing a polyamic acid ester, the polymer solution obtained by polymerization is poured into a non-solvent such as alcohol or water, the polymer is isolated, and then redissolved in an appropriate solvent and used for molding. The method and the method of using the polymer obtained by superposition | polymerization as it is for a shaping | molding are mentioned preferably. When adjusting the molding dope by re-dissolving, the above-mentioned solvent used for polymer polymerization can be used.

  The concentration of the polymer in the dope for molding is not particularly limited because the preferable concentration varies depending on the type of polymer, but is 0.1 wt% to 30 wt%, preferably 1 wt% to 25 wt%.

The molding dope as described above has excellent moldability and can be formed into a fiber, a film, a pulp-like particle or the like by a wet method or a dry jet wet method.
The dry jet wet method is a method in which a dope discharged from a spinning die or a forming die is once introduced into a coagulation bath after passing through a gas atmosphere, and in particular, the surface of a molded product is smoothed, the draft is increased, etc. Is effective.

The discharged (molded) dope is immersed in a coagulating liquid to obtain a coagulated product.
Here, as the coagulating liquid, a mixed solvent of an amide solvent and water can be used. Amide solvents include N, N, N ', N'-tetramethylurea (TMU), N, N-dimethylacetamide (DMAC), N, N-diethylacetamide (DEAC), N, N-dimethylpropionamide (DMPR), N, N-dimethylbutyramide (NMBA), N, N-dimethylisobutyramide (NMIB), N-methylpyrrolidone-2 (NMP), N-ethylpyrrolidone-2 (NEP), N-methylcaprolactam (NMC), N, N-dimethylmethoxyacetamide, N-acetylpyrrolidine (NAPR), N-acetylpiperidine, N-methylpiperidone-2 (NMPD), N, N'-dimethylethyleneurea, N, N'-dimethylpropylene Examples thereof include urea, N, N, N ′, N′-tetramethylmalonamide, N-acetylpyrrolidone, and the like, or a mixed solvent thereof.

As a mixing ratio of the amide solvent and water, 50% by weight or more of the coagulation liquid is water, and more preferably 55% by weight or more is water. When the amount is less than 50% by weight, the solidification property is not sufficient and handling becomes difficult.
Next, the obtained solidified product is immersed in a swelling agent, and then stretched under an appropriate stretching ratio, followed by drying to obtain a polyimide precursor molded product.

  Here, as the swelling agent, a mixed solvent of amide solvent and water that can swell without dissolving the filament can be used. Amide solvents include N, N, N ', N'-tetramethylurea (TMU), N, N-dimethylacetamide (DMAC), N, N-diethylacetamide (DEAC), N, N-dimethylpropionamide (DMPR), N, N-dimethylbutyramide (NMBA), N, N-dimethylisobutyramide (NMIB), N-methylpyrrolidone-2 (NMP), N-ethylpyrrolidone-2 (NEP), N-methylcaprolactam (NMC), N, N-dimethylmethoxyacetamide, N-acetylpyrrolidine (NAPR), N-acetylpiperidine, N-methylpiperidone-2 (NMPD), N, N'-dimethylethyleneurea, N, N'-dimethylpropylene Examples thereof include urea, N, N, N ′, N′-tetramethylmalonamide, N-acetylpyrrolidone, and the like, or a mixed solvent thereof.

  As a mixing ratio of the amide solvent and water, 50% by weight or more of the swelling agent is an amide solvent, and more preferably 55% by weight or more is an amide solvent. When the amount is less than 50% by weight, the swelling effect is not sufficient, and it is difficult to perform the stretching treatment.

  As an example of these, a forming dope comprising a polyamic acid ester and an amide solvent is dry-jetted into a coagulating liquid comprising a mixed solution of water / N-methyl-2-pyrrolidone = 70/30 (wt / wt). It is discharged by a wet method to complete coagulation, and subsequently passed through a swelling agent composed of a mixed solution of water / N-methyl-2-pyrrolidone = 30/70 (wt / wt) to swell the coagulated yarn. After swelling, a highly oriented polyimide precursor molding can be obtained by stretching, washing with water and drying.

Subsequently, a highly oriented polyimide molded product can be obtained by heat-treating the polyimide precursor molded product.
As temperature to heat-process, it is the range of 200-600 degreeC, and the range of 250-550 degreeC is preferable. In addition, the heat treatment can be performed in air or in an inert atmosphere such as nitrogen or argon.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these.
The intrinsic viscosity (ηinh) is a value measured at 30 ° C. with a polymer concentration of 0.5 g / dl using 3 wt% LiCl N-methyl-2-pyrrolidone.

[Reference Example 1]
200 g of pyromellitic anhydride (hereinafter sometimes referred to as PMDA) and 600 ml of dehydrated ethanol were mixed and refluxed to completely dissolve PMDA, and then 300 ml of ethanol was distilled off under reduced pressure. After cooling the resulting reaction product, the precipitate was filtered off and washed several times with ethyl acetate to obtain 2,5-dicarbomethoxyterephthalic acid. The obtained 2,5-dicarbomethoxyterephthalic acid (70 g) was dispersed in ethyl acetate (500 ml), and then reacted until oxalyl chloride (65 g) was added and completely dissolved. After removing the solvent by concentration under reduced pressure, the acid chloride obtained by recrystallization with hexane was confirmed to be 2,5-dicarbomethoxyterephthalic acid chloride as a result of NMR and infrared analysis. 3% by weight of lithium chloride dehydrated and dried at 250 ° C. was dissolved in N-methylpyrrolidone (hereinafter sometimes referred to as NMP), and 1.4852 g of paraphenylenediamine was dissolved in 100 ml of the above solvent in a dry nitrogen stream. The amine solution was kept at −10 ° C. by external cooling, and trimethylsilyl chloride (1.8 ml) was added. Further, 2.3838 g of the above-mentioned 2,5-dicarbomethoxyterephthalic acid chloride and 1.3941 g of terephthalic acid chloride were added, and the polymerization reaction was allowed to proceed for 1 hour. Further, stirring was continued at room temperature for 2 hours to complete the polymerization reaction. After completion of the reaction, the temperature was returned to room temperature and poured into a large amount of ion exchange water to precipitate a polymer. The obtained polymer was separated by filtration, further washed with ethanol and acetone, and then vacuum-dried. The ηinh measured with a 3 wt% LiCl N-methyl-2-pyrrolidone solution was 4.3.
The polymer was dissolved in a 3 wt% LiCl NMP solution at a concentration of 8 wt% to prepare a molding polymer dope.

[Example 1]
The obtained dope for molding was discharged into a 30 wt% NMP aqueous solution having a base of 0.3 mm and a discharge temperature of 50 ° C. at 50 ° C. The solidified yarn obtained was immersed in a 70 wt% NMP aqueous solution and swollen, and then 1.8 times Stretched. A polyamic acid ester fiber was obtained by washing with water and drying at 150 ° C. The fineness of the obtained fiber was 18.26 dtex, and the tensile modulus was 25.4 GPa.

  Furthermore, the polyamic acid ester fiber was heat-treated at 450 ° C. for 10 minutes to produce a polyimide fiber. The resulting fiber had a fineness of 14.2 dtex and a tensile modulus of 75.2 GPa.

[Comparative Example 1]
An attempt was made to draw the coagulated yarn obtained by discharging the dope for molding obtained in Reference Example 1 into a 30 wt% NMP aqueous solution having a base of 0.3 mm and a discharge temperature of 50 ° C. at 50 ° C., but could not be drawn. Therefore, the unstretched solidified yarn was dried at 150 ° C. to obtain a polyamic acid ester fiber. The fineness of the obtained fiber was 35.31 dtex, and the tensile modulus was 6.7 GPa.

  Furthermore, the polyamic acid ester fiber was heat-treated at 450 ° C. for 10 minutes to produce a polyimide fiber. The fineness of the obtained fiber was 25.96 dtex, and the tensile modulus was 13.3 GPa.

Claims (6)

Formula (I)
(R ₁ is selected from an aliphatic alcohol residue having 1 to 18 carbon atoms, an aromatic alcohol residue having 7 to 18 carbon atoms, and an alicyclic alcohol residue having 6 to 18 carbon atoms. Or Ar ₁ is a divalent aromatic group selected from any of the following:
After forming a molding dope containing a polyamic acid ester whose main component is a repeating unit represented by the formula, the obtained molding is immersed in a coagulation liquid to obtain a coagulation, and then the coagulation is swollen. A method for producing a polyimide precursor molded product, wherein the polyimide precursor molded product is dipped in, and then stretched.   The method for producing a polyimide precursor molded product according to claim 1, wherein the coagulation liquid is a mixed liquid composed of water and an amide solvent, and the content of water in the mixed liquid is 50 wt% or more. .   The polyimide precursor according to claim 2, wherein the amide solvent is at least one selected from the group consisting of N-methyl-2-pyrrolidone, N, N-dimethylacetamide and N, N dimethylformamide. Manufacturing method of body molded product.   The polyimide precursor molding obtained by the method in any one of Claims 1-3.   A method for producing a polyimide molded product comprising heat-treating a polyimide precursor molded product obtained by the method according to claim 1.   A polyimide molded product obtained by the method of claim 5.