JP2011131455A - Method for producing polyimide molded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for independently utilizing a polyimide film in which imidization is perfectly completed. <P>SOLUTION: The method of producing polyimide molded body is characterized in that the polyimide film that contains a biphenyltetracarboxylic acid component as the acid component of polyimide is crushed into powder whose volume-average particle size is 200 μm or less and, substantially, only the powder is molded. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a polyimide molded body by reusing a polyimide film which is difficult to reuse by itself.

  Polyimide films are engineering plastics with excellent heat resistance, mechanical properties, sliding properties, and chemical resistance, and are used in various fields, mainly for electrical and electronic equipment. Many thermoplastic engineering plastics, such as polypropylene and polyethylene terephthalate, can be reused by being melted by heating and then molded or mixed with a single or unused product.

  In contrast, polyimide films generally do not have a clear melting point unlike engineer plastics as described above, are non-thermoplastic, and are resistant to chemicals such as organic solvents. Cannot be reused. For this reason, the polyimide film which cannot be used as a product due to the ears and ends of the polyimide film or other factors is often treated as waste.

  In order to reuse these polyimide films, the polyimide film is cut and cut into small pieces, mixed with a polyamic acid solution in an amount of about 2 to 70% by weight, and a polyimide sheet is prepared from the polyamic acid solution containing the small pieces (Patent Document) 1) or a polyimide resin molded product obtained by molding a resin molded product mainly composed of polyimide to be reused or a mixture of 1 to 90 parts by weight of a crushed product of a polyimide resin raw material to 10 to 99 parts by weight. (Patent Document 2) has been proposed. These small pieces, crushed products of films, etc. use polyimide that has been completely imidized, and it has not been possible to produce a molded body using only the polyimide powder. Therefore, in these documents, in addition to the polyimide film to be reused, a new polyamic acid or a polyimide powder that has not been imidized is used, and in order to reuse, a new polyamic acid or polyimide powder is used. Therefore, there is a problem in cost for re-use.

  On the other hand, a polyimide film containing a biphenyltetracarboxylic acid component as an acid component of polyimide is well known (Patent Document 3). However, it is not described that these films are crushed and reused, and even if they are reused, they are mixed with other substances and formed into a form that is easy to mold. Yes, the polyimide film was not used alone for molding.

JP 2006-131753 A JP 2006-232996 A JP 2005-119159 A

  This invention provides the method of utilizing independently the polyimide film in which imidation was completed completely in view of the problem of the said prior art.

In order to solve the above problems, the present invention employs the following means. That is, the present invention
(1) Manufacture of a polyimide molded body characterized by pulverizing a polyimide film containing a biphenyltetracarboxylic acid component as an acid component of polyimide into a powder having a volume average particle diameter of 200 μm or less and substantially molding only this powder. Method,
(2) The method for producing a polyimide molded body according to the above (1), wherein the content of the biphenyltetracarboxylic acid component is 2 to 100 mol% with respect to the total acid component,
(3) The method for producing a polyimide molded body according to (1) or (2) above, wherein both the bending elongation and the tensile elongation of the molded body are 2% or more.

  Although it is the manufacturing method of the polyimide molded body of this invention, according to this method, the desired polyimide molded body can be obtained by reusing the polyimide film conventionally made impossible to reuse alone.

  In addition, when reused, the molded product can be formed without using other polyimide resin or powder other than the polyimide film, and it is necessary to create a new polyimide resin and powder for reuse. As a result, the number of steps involved in reuse can be greatly reduced.

  The present invention will be specifically described below.

  The present invention provides a polyimide molded body characterized in that a polyimide film containing a biphenyltetracarboxylic acid component as an acid component of polyimide is pulverized into a powder having a volume average particle diameter of 200 μm or less and substantially only this powder is molded. It is a manufacturing method. In the present invention, “acid component” is a generic term including “acid” and “acid dihydrate”, and “acid component” in a polymer such as a film constitutes a polymer. It means an “acid residue derived from an acid component”.

  A polyimide film is usually produced by reacting a tetracarboxylic dianhydride compound and a diamine compound in an organic solvent, casting the obtained polyamic acid solution on a support, and proceeding imidization. The present invention is characterized in that at least biphenyltetracarboxylic acid is contained as the tetracarboxylic acid component. The amount of biphenyltetracarboxylic acid to be used is preferably 2 to 100 mol% with respect to the total acid component, and the lower limit thereof is preferably 5 mol%, 15 mol% and 25 mol% successively. Usable biphenyltetracarboxylic acid components include 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 2,3 ′, 3,4′-biphenyltetracarboxylic acid, and 2,2 ′, 3,3′-biphenyl. Examples thereof include tetracarboxylic acids, and amide-forming derivatives and acid anhydrides thereof. Of these, the most preferred biphenyltetracarboxylic acid component is 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride. This biphenyltetracarboxylic acid component may be used alone or in combination of two or more, and an acid component other than the above may be used in combination.

  Specific examples of the acid component used in combination here include pyromellitic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, oxydiphthalic acid, 2,3,6,7-naphthalenedicarboxylic acid, 2,2 -Acid anhydrides such as bis (3,4-dicarboxyphenyl) ether, pyridine-2,3,5,6-tetracarboxylic acid and amide-forming derivatives thereof.

  As the diamine component constituting the polyimide of the present invention, paraphenylenediamine, metaphenylenediamine, benzidine, paraxylylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 2,2-bis (4-aminophenoxy) Phenyl) propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4 ′ -Bis (3-aminophenoxy) biphenyl and their amides Forming derivatives thereof. Of these, paraphenylenediamine and 4,4'-diaminodiphenyl ether are preferred. These diamine components may be used alone or in combination of two or more.

  A typical method for producing a polyimide film is as follows. In a separable flask, diamines such as 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, and paraphenylenediamine are used alone or in combination, and an organic solvent such as N, N′-dimethylacetamide is further added. Stir at room temperature under a nitrogen atmosphere. After stirring for about 1 hour, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride were added in several portions. After further stirring for about 1 hour, pyromellitic acid 2 An anhydrous N, N′-dimethylacetamide solution is added dropwise over 30 minutes, and the mixture is further stirred for about 1 hour to obtain a polyamic acid solution. The obtained polyamic acid is taken on a polyester film, and a uniform film is formed using a spin coater. This is heated and dried in an oven at 100 ° C. for 1 hour to obtain a self-supporting polyamic acid film. The self-supporting polyamic acid film is peeled from the polyester film, fixed to a metal frame, and heat-treated at 200 to 400 ° C. to obtain a polyimide film.

  In addition, if the polyimide film used for this invention is a polyimide film containing a biphenyl tetracarboxylic acid component as an acid component, the polyimide film currently mass-produced industrially can be utilized.

  In the present invention, the polyimide film is pulverized. As a pulverizer, a freezer mill, a ball mill, a bead mill, a sand mill, a jet mill, a turbo mill, an atomizer mill, an impact mill, and the like can be used, and a plurality of different pulverizing devices may be used in combination. In addition, the polyimide film can be easily pulverized by chemical treatment or heating before pulverization, or can be adjusted to a desired size by cutting. The size of the pulverized particles needs to have a volume average particle size of 200 μm or less, more preferably 10 to 150 μm, and still more preferably a fine powder of 15 to 80 μm. This is because if the volume average particle diameter of the polyimide powder is larger than 200 μm, the bulk density increases, and a sufficient density cannot be obtained when formed into a molded body. The density of the resin is related to the strength of the molded body, and if a sufficient density cannot be obtained, the resin becomes brittle.

  The greatest feature of the present invention resides in that the polyimide powder obtained as described above is molded substantially alone. Even if the conventional polyimide film is made into a powder, it cannot be formed alone. “Substantially” may be used alone or may contain a small amount of other substances, for example, a polyimide film other than the polyimide film defined in the present invention.

  The method for molding the polyimide powder in the present invention is not particularly limited, and examples thereof include a hot press in which heating and pressing are performed simultaneously. Moreover, you may dry the powder to be used before shaping | molding, or you may perform the pre-molding which only pressurizes, without applying heat before performing a hot press. Further, these steps may be performed in an atmosphere using an inert gas such as nitrogen.

  The obtained molded body preferably has the same physical properties as a normal polyimide molded body, and both the bending elongation and the tensile elongation are preferably 2% or more. The flexural modulus is preferably 2 GPa or more and the bending strength is preferably 50 MPa or more.

  Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited only to these examples. In addition, the physical property in each Example was measured with the following method.

<Volume average particle diameter>
Measurement was performed using a laser type particle size distribution measuring machine LMS-30 manufactured by Seishin Corporation.

<Bending elongation, bending elongation>
Measured according to ASTM D790.

<Tensile elongation, tensile strength>
Measured according to ASTM D1708.

Example 1
(Making polyimide film)
In a 300 ml separable flask equipped with a chemical stirrer, 4.94 g (0.065 mol) of 4,4′-diaminodiphenyl ether, 6.99 g (0.065 mol) of paraphenylenediamine, 189.32 g of N, N′-dimethylacetamide And stirred at room temperature under a nitrogen atmosphere. After stirring for 60 minutes, 13.3 g (0.045 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 14.11 g (0.065 mol) of pyromellitic dianhydride were divided into several times. After stirring for 180 minutes, 14.09 g of a pyromellitic dianhydride N, N′-dimethylacetamide solution (6 wt%) was added dropwise over 30 minutes, and the mixture was further stirred for 60 minutes to obtain a polyamic acid solution. Obtained.

  Part of the obtained polyamic acid was taken on a polyester film, and a uniform film was formed using a spin coater. This was heated and dried in an oven at 100 ° C. for 1 hour to obtain a self-supporting polyamic acid film.

The polyimide film was obtained by peeling the self-supporting polyamic acid film from the polyester film, fixing it to a metal frame, and performing heat treatment at 200 ° C. for 30 minutes, 300 ° C. for 20 minutes, and 400 ° C. for 5 minutes. .
The film thickness at this time was 53 μm.

(Making polyimide powder)
The polyimide film obtained by the above method was cut with a shredder and then pulverized with a jet mill. When the obtained powder was measured with a laser type particle size distribution measuring machine LMS-30 manufactured by Seishin Enterprise, the volume average particle diameter was 63 μm.

(Creation of molded body)
Using this powder, a compact was produced from the powder by a hot press method. The powder was put into a molding machine, the temperature was raised to 400 ° C. under a pressure of 2.0 ton / cm ² , and this state was maintained for 30 minutes to obtain a molded body. Table 1 shows the physical properties of the obtained molded body.

Example 2
(Making polyimide film)
In a 300 ml separable flask equipped with a chemical stirrer, 20.02 g (0.100 mol) of 4,4′-diaminodiphenyl ether and 182.98 g of N, N′-dimethylacetamide were placed and stirred at room temperature in a nitrogen atmosphere. After stirring for 60 minutes, 28.54 g (0.097 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added in several portions, and after further stirring for 120 minutes, pyromellitic dianhydride was added. 10.9 g of N, N′-dimethylacetamide solution (6 wt%) of the product was added dropwise over 30 minutes, and the mixture was further stirred for 60 minutes to obtain a polyamic acid solution.

  Part of the obtained polyamic acid was taken on a polyester film, and a uniform film was formed using a spin coater. This was heated and dried in an oven at 100 ° C. for 1 hour to obtain a self-supporting polyamic acid film.

  The polyimide film was obtained by peeling the self-supporting polyamic acid film from the polyester film, fixing it to a metal frame, and performing heat treatment at 200 ° C. for 30 minutes, 300 ° C. for 20 minutes, and 400 ° C. for 5 minutes. . At this time, the film thickness was 42 μm.

(Making polyimide powder)
The obtained film was used, cut with a shredder, and pulverized with a jet mill. When the obtained powder was measured with a laser type particle size distribution measuring machine LMS-30 manufactured by Seishin Enterprise, the volume average particle size was 70 μm.

(Creation of molded body)
Using this powder, a compact was produced from the powder by a hot press method. The powder was put into a molding machine, the temperature was raised to 400 ° C. under a pressure of 2.0 ton / cm ² , and this state was maintained for 30 minutes to obtain a molded body. Table 1 shows the physical properties of the obtained molded body.

Example 3
(Making polyimide film)
In a 300 ml separable flask equipped with a chemical stirrer, 14.06 g (0.130 mol) of paraphenylenediamine and 190.87 g of N, N′-dimethylacetamide were placed and stirred at room temperature in a nitrogen atmosphere. After stirring for 60 minutes, 37.10 g (0.126 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added in several portions, and after further stirring for 120 minutes, pyromellitic dianhydride was added. 14.18 g of N, N′-dimethylacetamide solution (6 wt%) was dropped over 30 minutes, and the mixture was further stirred for 60 minutes to obtain a polyamic acid solution.

  Part of the obtained polyamic acid was taken on a polyester film, and a uniform film was formed using a spin coater. This was heated and dried in an oven at 100 ° C. for 1 hour to obtain a self-supporting polyamic acid film.

The polyimide film was obtained by peeling the self-supporting polyamic acid film from the polyester film, fixing it to a metal frame, and performing heat treatment at 200 ° C. for 30 minutes, 300 ° C. for 20 minutes, and 400 ° C. for 5 minutes. .
The film thickness at this time was 48 μm.

(Making polyimide powder)
The obtained film was cut with a shredder and then pulverized with a jet mill. When the obtained powder was measured with a laser type particle size distribution measuring machine LMS-30 manufactured by Seishin Enterprise, the volume average particle size was 68 μm.

(Creation of molded body)
Using this powder, a compact was produced from the powder by a hot press method. The powder was put into a molding machine, and the temperature was raised to 400 ° C. under a pressure of 2.0 [ton / cm ² ], and this state was maintained for 30 minutes. Table 1 shows the physical properties of the obtained molded body.

Example 4
(Making polyimide film)
In a 300 ml separable flask equipped with a chemical stirrer, 23.03 g (0.115 mol) of 4,4′-diaminodiphenyl ether and 185.69 g of N, N′-dimethylacetamide were placed and stirred at room temperature in a nitrogen atmosphere. After stirring for 60 minutes, 8.46 g (0.028 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 18.06 g (0.082 mol) of pyromellitic dianhydride were divided into several times. After stirring for 120 minutes, 12.54 g of N, N′-dimethylacetamide solution of pyromellitic dianhydride (6 wt%) was added dropwise over 30 minutes, and the mixture was further stirred for 60 minutes to obtain a polyamic acid solution. Obtained.

  Part of the obtained polyamic acid was taken on a polyester film, and a uniform film was formed using a spin coater. This was heated and dried in an oven at 100 ° C. for 1 hour to obtain a self-supporting polyamic acid film.

  The polyimide film was obtained by peeling the self-supporting polyamic acid film from the polyester film, fixing it to a metal frame, and performing heat treatment at 200 ° C. for 30 minutes, 300 ° C. for 20 minutes, and 400 ° C. for 5 minutes. . The film thickness at this time was 47 μm.

(Making polyimide powder)
The obtained film was cut with a shredder and then pulverized with a jet mill. The obtained powder was measured with a laser type particle size distribution analyzer LMS-30 manufactured by Seishin Corporation. The volume average particle size was 65 μm.

(Creation of molded body)
Using this powder, a compact was produced from the powder by a hot press method. The powder was put into a molding machine, and the temperature was raised to 400 ° C. under a pressure of 2.0 [ton / cm ² ], and this state was maintained for 30 minutes. Table 1 shows the physical properties of the obtained molded body.

Comparative Example 1
(Making polyimide film)
In a 300 ml separable flask equipped with a chemical stirrer, 25.03 g (0.125 mol) of 4,4′-diaminodiphenyl ether and 192.50 g of N, N′-dimethylacetamide were placed and stirred at room temperature in a nitrogen atmosphere. After stirring for 60 minutes, 26.45 g (0.121 mol) of pyromellitic dianhydride was added in several portions. After further stirring for 120 minutes, an N, N′-dimethylacetamide solution of pyromellitic dianhydride ( 6 wt%) 13.63 g was added dropwise over 30 minutes and stirred for 60 minutes to obtain a polyamic acid solution.

  Part of the obtained polyamic acid was taken on a polyester film, and a uniform film was formed using a spin coater. This was heated and dried in an oven at 100 ° C. for 1 hour to obtain a self-supporting polyamic acid film.

  The polyimide film was obtained by peeling the self-supporting polyamic acid film from the polyester film, holding it with a metal frame, and performing heat treatment under conditions of 200 ° C. for 30 minutes, 300 ° C. for 20 minutes, and 400 ° C. for 5 minutes. . The film thickness at this time was 55 μm.

(Making polyimide powder)
The polyimide film was cut with a shredder and pulverized with a jet mill. When the obtained powder was measured with a laser type particle size distribution measuring machine LMS-30 manufactured by Seishin Enterprise, the volume average particle diameter was 63 μm.

(Creation of molded body)
Using this powder, a compact was produced from the powder by a hot press method. The powder was put into a molding machine and the temperature was raised to 400 ° C. with a pressure of 2.0 ton / cm ² , and this state was maintained for 30 minutes. However, the adhesion between the powders is insufficient. A molded product could not be obtained.

Comparative Example 2
(Making polyimide film)
In a 300 ml separable flask equipped with a chemical stirrer, 20.02 g (0.100 mol) of 4,4′-diaminodiphenyl ether and 182.98 g of N, N′-dimethylacetamide were placed and stirred at room temperature in a nitrogen atmosphere. After stirring for 60 minutes, 28.54 g (0.097 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added in several portions, and after further stirring for 120 minutes, pyromellitic dianhydride was added. 10.9 g of N, N′-dimethylacetamide solution (6 wt%) of the product was added dropwise over 30 minutes, and the mixture was further stirred for 60 minutes to obtain a polyamic acid solution.

  Part of the obtained polyamic acid was taken on a polyester film, and a uniform film was formed using a spin coater. This was heated and dried in an oven at 100 ° C. for 1 hour to obtain a self-supporting polyamic acid film.

The polyimide film was obtained by peeling the self-supporting polyamic acid film from the polyester film, fixing it to a metal frame, and performing heat treatment at 200 ° C. for 30 minutes, 300 ° C. for 20 minutes, and 400 ° C. for 5 minutes. .
At this time, the film thickness was 42 μm.

(Making polyimide powder)
The obtained film was cut with a scissors and then pulverized with a jet mill. When the obtained powder was measured with a laser type particle size distribution measuring machine LMS-30 manufactured by Seishin Enterprise, the volume average particle size was 252 μm.

(Creation of molded body)
Using this powder, a compact was produced from the powder by a hot press method. The powder was put into a molding machine and the temperature was raised to 400 ° C. with a pressure of 2.0 [ton / cm ² ] applied, and this state was maintained for 30 minutes, but the adhesion between the powders was insufficient. Therefore, a molded body could not be obtained.

  Since the polyimide powder of the present invention can produce a molded body equivalent to an existing polyimide molded body only with the prepared powder, it is equivalent to an existing polyimide molded body only from a polyimide film for reuse. Resin can be made.

Claims (3)

A method for producing a polyimide molded body, comprising: pulverizing a polyimide film containing a biphenyltetracarboxylic acid component as an acid component of polyimide into a powder having a volume average particle diameter of 200 μm or less, and substantially molding only this powder. 2. The method for producing a polyimide molded body according to claim 1, wherein the content of the biphenyltetracarboxylic acid component is 2 to 100 mol% with respect to the total acid component. The method for producing a polyimide molded body according to claim 1 or 2, wherein both the bending elongation and tensile elongation of the molded body are 2% or more.