JP2626827B2 - Polyimide stretch molded article and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is made of a specific aromatic polyimide of pyromellitic acid type, and has highly excellent physical properties, particularly high orientation having extremely high Young's modulus (tensile modulus). The present invention relates to a stretched aromatic polyimide molded article (for example, a film, a fiber or the like), and to a novel method for producing the stretched polyimide article under specific conditions.

The pyromellitic acid-based polyimide stretch molded article of the present invention has a high level of tensile strength by using a specific diamine component, as compared with this kind of aromatic polyimide film molded by a conventional solution casting method. Since it has strength, heat resistance, and the like, and has an extremely high Young's modulus, it can be suitably used for various applications, particularly as a thin film or a thin fiber.

[Description of Prior Art]

Conventionally, as a method for producing an aromatic polyimide film (stretched film) having heat shrinkability, for example, as described in JP-B-57-41330, a biphenyltetralucanoic acid-based aromatic polyimide precursor is used. Solution (polyamic acid or polyamic acid) at 20-200 ° C
At a temperature of 200 to 300 ° C., and dried until the volatile matter content becomes 10% by weight or less, at least 50% of the amic acid bonds of the polyamic acid obtained. A method has been proposed in which a polyimide film whose% is converted to an imide bond is obtained, and then the polyimide film is stretched in at least one direction at a temperature of 100 to 500 ° C so that the stretching ratio becomes 1.05 to 5 times.

However, in the above-mentioned known method, although it is possible to produce a specific biphenyltetracarboxylic acid-based polyimide film having heat shrinkability, the direction obtained from pyromellitic acids and 4,4′-diaminodiphenyl ether is preferred. As for the “self-supporting unstretched film” composed of an aromatic polyamic acid and an organic polar solvent, the stretching operation itself was not easy, and the obtained stretched molded product did not have sufficiently high physical properties.

[Problems to be solved]

An object of the present invention is to provide a pyromellitic acid-based aromatic polyimide stretch molded article having high physical properties (in particular, having a high Young's modulus) and to easily produce the aromatic polyimide stretch molded article having high physical properties. Is to provide a way to

[Means to solve the problem]

The first invention of this application is directed to an aromatic tetracarboxylic acid component containing pyromellitic acid of 80 mol% or more and 3,4'-
An aromatic polyimide obtained from an aromatic diamine component containing at least 80 mol% of diaminodiphenyl ether, and having a tensile strength of 20 to 100 kg / mm ² and a Young's modulus of 7
Relates polyimide stretched moldings are 00~3000kg / mm ^2, further, the second invention, an aromatic tetracarboxylic acid component containing a pyromellitic acid or 80 mol%, 3,4'-diaminodiphenyl ether Is formed from an aromatic polyamic acid solution obtained by polymerizing an aromatic diamine component containing at least 80 mol% of the same in an organic polar solvent, and then forming the polyamic acid. The thin film or fibrous body of the solution is heated to 200 ° C. or more to form a polyimide molded body, and the polyimide molded body (unstretched molded body) is stretched 1.5 to 3.5 times at a temperature of 250 to 450 ° C. Finally, the present invention relates to a method for producing a stretched polyimide article, wherein the stretched article is subjected to a heat treatment at a temperature of 200 ° C. or higher.

Hereinafter, the invention of this application will be described in more detail.

The aromatic polyimide in the stretched polyimide molded article of the present invention is, for example, pyromellitic acid or its acid dianhydride, or at least one kind of pyromellitic acids selected from acid esterified products thereof, at least 80 mol%,
Preferably, an aromatic tetracarboxylic acid component containing 90 mol% or more and 3,4′-diaminodiphenyl ether
An aromatic diamine component containing at least 90% by mole, preferably at least 90% by mole, is composed of a pyromellitic acid-based aromatic polyimide obtained by polymerization using approximately equimolar amounts of both components.

The pyromellitic acid-based aromatic polyimide has a secondary transition temperature of about 280 to 380 ° C., particularly preferably 300 to 360 °.
It is preferable that the temperature is about ° C.

In the above-mentioned aromatic tetracarboxylic acid component, examples of the tetracarboxylic acid compounds that can be used in addition to pyromellitic acids include biphenyltetracarboxylic acid or an acid dianhydride thereof, benzophenonetetracarboxylic acid or an acid dianhydride thereof. Anhydride, bis (3,4-dicarboxyphenyl) methane or its acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane or its acid dianhydride, bis (3,4-dicarboxylic acid) (Carboxyphenyl) sulfone or its acid dianhydride.

In the aromatic diamine component, examples of the aromatic diamine compounds that can be used in addition to 3,4′-diaminodiphenyl ether include, for example, 4,4′-diaminodiphenyl ether and 3,3′-diaminodiphenyl ether. Other diaminodiphenyl ethers, 4,
4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane,
Diaminodiphenylalkanes such as 3,4'-diaminodiphenylpropane, and 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide and the like can be mentioned, in particular, 4,4'-diaminodiphenylether And diaminodiphenyl ethers.

In the polyimide stretch molding method of the present invention, if the content of 3,4'-diaminodiphenyl ether in the aromatic diamine component for producing an aromatic polyimide is too small, the diamine component having such a low content is used. It is difficult to stretch the aromatic polyimide molded article obtained from the above, and the stretched molded article made of the aromatic polyimide is deteriorated in mechanical properties.

The aromatic polyimide stretch molded article of the present invention is obtained, in particular, from the aforementioned aromatic tetracarboxylic acid component mainly containing pyromellitic acids and the aromatic diamine component mainly containing 3,4′-diaminodiphenyl ether. It has a tensile strength of about 20 to 100 kg / mm ² , preferably about 25 to 95 kg / mm ² , and a Young's modulus (tensile modulus of elasticity) of 700 to 3000 kg. /
mm ² , and preferably about 750 to 2600 kg / mm ² .

The stretched polyimide molded article of the present invention has the above-described tensile strength and Young's modulus, and has an elongation at break of 10%.
% Or less, particularly preferably about 2 to 8%, for example, a film (sheet) having a thickness of 500 μm or less, particularly about 1 to 200 μm, or a diameter of 1000 μm or less,
In particular, it is preferably a highly oriented aromatic polyimide stretch molded article such as a fibrous body having a thickness of about 1 to 500 μm.

Conventionally, such as polyimide stretched molded article of the present invention, high heat resistance, tensile holds the like strength 20 kg / mm ² or more, aromatic polyimides stretch forming of "pyromellitic acid having a Young's modulus 700 kg / mm ² or more The body '' was completely unknown.

In the method for producing a stretched polyimide molded article of the present invention, for example, first, an aromatic tetracarboxylic acid component mainly containing the aforementioned pyromellitic acids and an aromatic diamine mainly containing 3,4′-diaminodiphenyl ether It is obtained by polymerizing roughly equimolar to the components (differences within ± 2.0 mol%, especially ± 1.5%) in an organic polar solvent, preferably at a temperature of 80 ° C or less, particularly preferably 0 to 60 ° C. Using a solution of "high molecular weight aromatic polyamic acid", form a thin film, fibrous body, etc. of the polyamic acid solution, and heat the thin film, fibrous body, etc. at a high temperature to remove the solvent Together with the polymer to form an unstretched polyimide molded article (unstretched molded article), and the unstretched molded article is stretched at a temperature of 250 to 450 ° C. at a draw ratio of 1.
By stretching to 5 to 3.5 times, a stretch molded article of pyromellitic acid-based aromatic polyimide is formed with good reproducibility, and finally, the stretch molded article is subjected to a heat treatment at a temperature of 200 ° C. or more, so that pyromellitic is obtained. An acid-based stretched polyimide product can be produced.

In the production method of the present invention, the "residue of aromatic diamine of polyimide" forming an unfinished molded article of pyromellitic acid-based aromatic polyimide is 3,4'-diaminodiphenyl ether (3,4 ' -DADE) is particularly important, and a polyimide consisting of a residue of a diamine other than the above 3,4'-DADE may not be able to perform sufficient stretching even at a high temperature, Even if stretching is possible, a polyimide stretched molded article having high physical properties cannot be obtained (see Comparative Example 2).

Further, the production method of the present invention is characterized in that a pyromellitic acid-based polyimide molded article (unstretched molded article) is stretched at a high temperature, for example, Comparative Examples 2 and 3
As shown in the above, the molded product of polyamic acid obtained from the aforementioned pyromellitic acid and 3,4'-diaminodiphenyl ether is stretched, and then the polymer forming the stretched molded product is imidized to obtain a polyimide. Even if a stretch molded article is manufactured, a polyimide stretch molded article having high physical properties cannot be obtained.

The organic polar solvent for polymerization used in the production of the aromatic polyamic acid described above is an organic polar solvent capable of uniformly dissolving the polyamic acid in an amount of 3% by weight or more, particularly 5% by weight or more. , N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-di-lower alkylcarboxamides such as N, N-methylethylacetamide, N -Methyl-2-pyrrolidone, dimethylsulfoxide, diethylsulfoxide, dimethylsulfone, diethylsulfone, hexamethylsulfoxide, and other organic polar solvents, and the organic polar solvents described above may be the same organic polar solvents. It is preferably a polar solvent.

The "unstretched molded article such as the aromatic polyimide film or fiber" used in the production method of the present invention is,
Having a self-supporting property, and a stretch ratio is a molded body that is not stretched to 1.2 times or more and is in a substantially unstretched state, and a method of producing an unstretched molded body is not particularly limited. Without using, for example, a polyamic acid solution uniformly dissolved in an organic polar solvent of the aromatic polyamic acid, a solution casting film forming method at a temperature of 40 to 150 ° C., particularly preferably 40 to 120 ° C. Film formation, or
From a liquid film or fibrous body formed by spinning at the same temperature, 200 ° C. or more, especially 200 ~
At a temperature of 400 ° C., most of the solvent is removed by evaporation, and at the same time, an aromatic polyamic acid is imidized to produce an undrawn molded article such as a polyimide film or solidified fiber.

In the production method of the present invention, the "unstretched molded article of polyimide" obtained as described above is stretched at a stretching temperature of 250 to 4
The film is stretched (uniaxially or biaxially stretched) at 50 ° C., preferably about 280 to 400 ° C., in at least one direction to 1.5 to 3.5 times, preferably about 1.8 to 3.2 times,
Heat treatment is performed at a high temperature of 0 ° C. or higher, preferably 200 to 550 ° C., particularly 250 to 530 ° C. to produce a pyromellitic acid-based aromatic polyimide stretch molded article.

The production of the “unstretched molded body” and the stretching operation thereof can be performed by known means. For example, both ends of the unstretched molded body are supported by a pair of support members provided at appropriate intervals on a base. The unstretched molded body is fixedly attached to the support member with a fastener such as a chuck, and the gap between the pair of support members is gradually widened along the base. By stretching the "unstretched molded article" to an appropriate stretching ratio.

When the above-mentioned stretched molded body is subjected to heat treatment at a temperature of 200 or more, at least both ends in the stretching direction of the stretched molded body to be subjected to the heat treatment are fixed at a fixed distance with a pair of support members, a frame, or the like. It is preferable to perform the heat treatment
Also, for example, a first heat treatment at a temperature of 200 to 280 ° C., a second heat treatment at a temperature of 280 to 350 ° C., and a tertiary heat treatment at a temperature higher than 350 are further performed in a multi-stage heat treatment. Can also be performed.

The above-mentioned heat treatment is optimally performed at a temperature of 350 to 550 ° C., especially 360 to 520 ° C. in the aromatic polyimide stretched molded article, since a stretched molded article with high physical properties can be obtained.

In the production method of the present invention, the aromatic polyamic acid used in the production of the polyimide molded article (unstretched molded article) is obtained from an aromatic tetracarboxylic acid component and an aromatic diamine component at a low temperature of about 60 ° C. or less. A polyamic acid-based soluble polyamic acid obtained by polymerization of (polyimide precursor) and the logarithmic viscosity (measurement temperature; 30 ° C., concentration;
5 g / 100 ml solvent, solvent; N, N-dimethylacetamide)
0.1 to 7, particularly about 0.2 to 5, the imidation ratio is 30% or less, particularly 20% or less, more preferably 10% or less, and the concentration of about 40% by weight in the above-mentioned organic polar solvent is obtained. Preferably, the polymer is a polymer that can be uniformly dissolved.

The logarithmic viscosity is a value calculated by the following equation.

The imidation rate is an imidation rate determined by an infrared analysis method (IR method). The absorbance at 1780 cm ⁻¹ , which is an absorption peak based on an imide bond in an infrared absorption spectrum of a sample, and an absorption based on a phenyl group are measured. 1510cm which is the peak
^The imidation ratio can be calculated from the ratio to the absorbance of ^-1 .

In the production method of the present invention, "a specific pyromellitic acid obtained from an aromatic tetracarboxylic acid component mainly containing pyromellitic acids and an aromatic diamine component mainly containing 3,4'-diaminodiphenyl ether is used. The main feature is that the system-based aromatic polyimide molded article (unstretched molded article) is stretched 1.5 to 3.5 times at a high temperature of 250 to 450 ° C. and finally heat-treated at a high temperature. By such a manufacturing method,
It is possible to produce a pyromellitic acid-based aromatic polyimide stretch molded article having high physical properties with good reproducibility.

〔Example〕

Examples 1 to 8 32.719 g (0.15 mol) of pyromellitic dianhydride and 3,4 '
-Aromatic polyamic acid solvent obtained by polymerizing 30.036 g (0.15 mol) of diaminodiphenyl ether in 565 g of an N, N-dimethylacetamide (DMAc) solvent at a polymerization temperature of 25 ° C. and a nitrogen atmosphere for 6 hours [ Polymer concentration; 10
%, Solution viscosity at 25 ° C (solution viscosity measured by a rotational viscometer); 130 poise, logarithmic viscosity (concentration: 0.5% by weight, measurement temperature: 30 ° C); 1.80].

Then, using the aromatic polyamic acid solution,
The solution was cast on a glass plate to a uniform thickness at about 50 ° C, and the resulting liquid thin film was dried at 55 ° C for 1 hour, further dried at 50 ° C for 24 hours, and then dried at 150 ° C. For 60 minutes at 200
Aromatic polyimide film based on pyromellitic acid (polymer imidation ratio: 60 minutes at 250 ° C and 120 minutes at 250 ° C)
90% or more, the second order transition temperature of the polymer;

The polyimide film was cut into rectangular pieces having a width of 10 mm and a length of 70 mm.
A pair of support members (width 10 mm) arranged on the substrate at an interval of mm
Install the film so that there is no slack, sandwich the film at both ends with a chuck and fix it.
After raising the temperature at a temperature raising rate of 1 ° C./sec and holding the film between the supporting members for 10 minutes at the stretching temperature shown in Table 1, one of the pair of supporting members is gradually moved within about 1 minute. Then, the distance between the supporting members was increased, and the polyimide film was stretched at the stretching ratio shown in Table 1.

In Examples 1 to 6, the physical properties of the stretched product thus obtained were measured.

In Examples 7 and 8, after performing the above-described stretching operation, the stretched polyimide film (stretched molded product)
With the stretched molded body attached to the support member, a heat treatment was further performed under the conditions shown in Table 1 to produce an aromatic polyimide stretched molded body.

Table 1 shows the physical properties of the stretched molded articles obtained as described above.

Comparative Example 1 A polyimide stretch molded article was produced in the same manner as in Example 1 except that the stretching ratio was set to 1.3.

Table 1 shows the physical properties of the stretched molded article obtained as described above.

Comparative Example 2 A polyamic acid solution was prepared in the same manner as in Example 1, except that 4,4'-diaminodiphenyl ether was used as the aromatic diamine component instead of 3,4'-diaminodiphenyl ether.

Then, a polyimide stretch molded article was produced in the same manner as in Example 1 except that the above-mentioned polyamic acid solution was used and the stretching ratio was set to 1.8.

Table 1 shows the physical properties of the stretched molded article obtained as described above.

[Functions and Effects of the Present Invention] The stretched aromatic polyimide molded article of the present invention is a film or fiber made of a highly heat-resistant aromatic polyimide obtained mainly from pyromellitic acids and 3,4'-diaminobiphenyl ether. Pyromellitic acid, which is a stretch-formed body such as a dendritic body and has high physical properties such as a tensile speed of 20 to 100 kg / mm ² and a Young's modulus (tensile elastic modulus) of 800 to 3000 kg / mm ² The present invention provides, for the first time, an aromatic polyimide stretch molded article.

The method for producing an aromatic polyimide stretched molded article of the present invention is mainly based on the use of an aromatic polyamic acid solution obtained from pyromellitic acids and 3,4'-diaminobiphenyl ether, and the molded polyimide is molded. This is a method in which the above-mentioned aromatic polyimide stretched molded article having high physical properties can be produced with good reproducibility by stretching the molded article (unstretched molded article) at a high temperature and subjecting it to heat treatment.

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Claims (2)

(57) [Claims] 1. An aromatic polyimide obtained from an aromatic tetracarboxylic acid component containing at least 80 mol% of pyromellitic acids and an aromatic diamine component containing at least 80 mol% of 3,4'-diaminodiphenyl ether. And a tensile strength of 20 to 100 kg / mm ² and a Young's modulus of 700
A stretched polyimide molded product of up to 3000 kg / mm ² . 2. An aromatic tetracarboxylic acid component containing at least 80 mol% of pyromellitic acids and an aromatic diamine component containing at least 80 mol% of 3,4'-diaminodiphenyl ether are substantially equimolar in organic polarity. Form a thin film or fibrous body from the aromatic polyamic acid solution obtained by polymerization in a solvent, and then heat the thin film or fibrous body of those polyamic acid solutions to 200 ° C or higher to form a polyimide molded body Then, the polyimide molded body is stretched 1.5 to 3.5 times at a temperature of 250 to 450 ° C., and finally, the stretched molded body is stretched by 20 times.
A method for producing a stretched polyimide article, comprising performing a heat treatment at a temperature of 0 ° C. or higher.