JPH06343B2 - Method for producing molded polyimide sheet - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a novel method for producing a sheet molded article composed of an aromatic polyimide sheet having concave portions (or convex portions) of various shapes.

BACKGROUND OF THE INVENTION Since aromatic polyimide has high heat resistance and excellent chemical and physical properties, it has attracted attention as a plastic material to be used under severe conditions, and many studies have been conducted. However, most of the aromatic polyimides known so far are used as a flat sheet-shaped body (including a film-shaped body). However, a method of industrially producing container-shaped molded articles of various shapes made of the aromatic polyimide sheet has not been known.

The reason for this is that most aromatic polyimides do not substantially have the thermoplasticity of ordinary plastics, so the aromatic polyimides are directly extruded or injected to form a container-shaped molded body. Alternatively, it is not possible to perform various known sheet moldings or the like using the aromatic polyimide sheet.

In order to make more effective use of the high heat resistance and high chemical resistance of aromatic polyimides, electrical and electronic equipment is used in which a container-shaped molded body made of aromatic polyimide is formed and subjected to various heat treatments or chemical treatments. It is expected from related industries that it can be used as a protective container for parts, electric / electronic devices, or a protective cover. However, due to the poor moldability of the aromatic polyimide as described above, it is desired. That is, it was not possible to industrially form a sheet molded body made of an aromatic polyimide sheet having the concave shape (the convex shape).

As described above, no method has hitherto been known for industrially producing a molded product such as a container made of an aromatic polyimide sheet having high heat resistance and excellent chemical and physical properties.

[Structure of the Invention] An object of the present invention is to provide a method for producing a polyimide sheet molded article such as a container formed from an aromatic polyimide sheet and having variously shaped concave portions (or convex portions). To do.

That is, the present invention uses a sheet body containing 100 parts by weight of an aromatic polyamic acid or aromatic polyimide and 10 to 150 parts by weight of an organic polar solvent, and a mold having a convex surface on at least one side can be used as the sheet body. And the end edge of the sheet body are fixed, and then the covering body in which the convex surface of the mold is wrapped in the sheet body is used.
The solvent is removed from the sheet body by heating to a temperature of 00 ° C., and the sheet body is contracted toward the convex surface of the mold to remove the solvent on the entire convex surface of the mold. The polyimide sheet characterized in that it is brought into close contact with the contracted sheet body, and finally, the mold is removed to obtain a molded body of an aromatic polyimide sheet having a concave portion having a shape corresponding to the convex surface of the mold. This is a method for producing a molded body.

Hereinafter, the manufacturing method of the present invention will be described in more detail with reference to the drawings.

1 to 3 are perspective views and cross-sectional views illustrating a part of the steps of the production method of the present invention, and FIGS. 4 to 5 are examples of polyimide sheet moldings obtained by the production method of the present invention. FIG.

6 to 8 are perspective views and cross-sectional views illustrating a part of the steps of another manufacturing method of the present invention, and FIG. 9 is another polyimide sheet molded body obtained by the manufacturing method of the present invention. It is a perspective view which shows an example.

The sheet is a "solvent-soluble high molecular weight aromatic polyamic acid" obtained by polymerizing an aromatic tetracarboxylic acid component composed of an aromatic tetracarboxylic acid or its acid dianhydride and an aromatic diamine component. Alternatively, 100 parts by weight of "aromatic polyimide" and 5% by weight or more, particularly preferably 8% by weight or more of the above-mentioned aromatic polyamic acid or aromatic polyimide can dissolve "organic polarities such as amide-based solvents and phenol-based solvents. Solvent ”10 to 150 parts by weight, particularly preferably 20 to 120
It is a flexible sheet body made of a polymer composition containing about parts by weight as a main component. The thickness of this sheet is about 1
It is preferably from 0 to 1000 μm, particularly preferably from 20 to 500 μm.

The polymer composition, in addition to the aromatic polyamic acid or aromatic polyimide and the organic polar solvent described above, known additives such as modifiers, antioxidants, plasticizers, inorganic fillers, other organic solvents. May be contained as long as it is about 10% by weight or less.

In addition, the term “sheet body” in the present invention generally includes any form called “thin film”, “film”, “sheet” and the like.

Examples of the aromatic tetracarboxylic acid component that can be used for producing the polymer solvent include, for example, 3,3 ′,
4,4'-biphenyltetracarboxylic acid, 2,3
3 ', 4'-biphenyltetracarboxylic acid, 3,3',
4,4′-benzophenone tetracarboxylic acid, bis (3,4-carboxyphenyl) methane, 2,2-bis (3,4-carboxyphenyl) propylene, pyromellitic acid, and dianhydrides of these tetracarboxylic acids Compounds, esterified products, salts and the like, or a mixture of these compounds. In the present invention, 3,
Biphenyltetracarboxylic acid dianhydride represented by 3 ', 4,4'-biphenyltetracarboxylic acid dianhydride and 2,3,3', 4'-biphenyltetracarboxylic acid dianhydride as a main component A sheet body formed from a polymer solution obtained by using the aromatic tetracarboxylic acid component (preferably containing about 60 mol% or more, more preferably 80 mol% or more) is preferable.

As the aromatic diamine component that can be used in the production of the polymer solution, for example, paraphenylenediamine,
Meta-phenylenediamine, 2,4-diaminotoluene,
4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminophenylmethane, 3,4'-diaminodiphenylmethane, 1,
4-bis (4-aminophenoxy) benzene, orthotrizine, orthotrizine sulfone, bis (4-aminophenoxy-phenyl) methane, bis (4-aminophenoxy-phenyl) sulfone and the like can be mentioned.

The sheet body is, for example, an aromatic tetracarboxylic acid component such as biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid, pyromellitic acid, or an acid dianhydride thereof, and phenylenediamine, diaminophenyl ether, diaminodiphenylmethane, diamino. An aromatic diamine component such as diphenyl sulfone is polymerized in an organic polar solvent at an appropriate polymerization temperature to produce a high-molecular-weight soluble polymer (aromatic polyamic acid or polyimide). 30 wt% polymer solution "was prepared, and the polymer solution was used as a dope solution for film formation, and was cast on the surface of a support having a smooth surface such as a metal belt or a metal drum. A thin film of polymer solution is formed (solution casting method), followed by about 50-
It can be obtained by a known method such as evaporating and removing at least a part of the organic polar solvent from the thin film at a temperature of 200 ° C. to form a self-supporting solidified film composed of the organic polar solvent and the polymer.

In the production of the above polymer solution, for example, 3,3 ′,
4,4'-biphenyltetracarboxylic acid, 2,3
Aromatic tetracarboxylic acid component containing biphenyltetracarboxylic acid such as 3 ', 4'-biphenyltetracarboxylic acid or its acid dianhydride as a main component, and aromatic diamine having two or more benzene rings as a main component When polymerizing with an aromatic diamine component, the polymerization solvent is an amide-based solvent, and if the polymerization temperature is a low temperature of about 60 ° C. or lower, a polyamic acid solution is obtained, and the polymerization solvent is a phenol-based solvent, If the polymerization temperature is a high temperature of about 140 ° C. or higher, a polyimide solution can be obtained. These solutions are preferable because they have high storage stability.

When an aromatic polyamic acid is used, its logarithmic viscosity is 0.4 to 5.0 (measurement conditions: 30 ° C., 0.5
g / 100 ml dimethylacetamide) is preferable, and when an aromatic polyimide is used, its logarithmic viscosity is 0.5 to 7.0 (measurement conditions: 50 ° C., 0.5 g / It is preferable to use one in the range of 100 ml parachlorophenol).

Examples of the polymerization solvent used for producing the polyamic acid solution include amide solvents such as N-methyl-2-pyrrolidone, dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, and dimethylsulfamide. As a polymerization solvent for producing a polyimide solution, phenol, cresol,
Phenolic solvents such as halogenated phenols (parachlorophenol etc.) can be mentioned.

In addition, as the organic polar solvent forming the above-mentioned sheet body, each polymerization solvent used at the time of producing each of the above-mentioned polymer solvents can be mentioned as it is.

In the manufacturing method of the present invention, using the above-described sheet body, as shown in FIGS. 1 to 3, a mold 12 having a convex surface on at least one side is formed into, for example, a polygonal shape (square shape, hexagonal shape). , Octagonal shape), elliptical shape, circular shape, a combination of these shapes, etc.
Wrap it as close as possible with the sheet body 1
As shown in FIG. 2, the end edge of 1 is fixed to the peripheral edge of the mold by a heat-resistant adhesive tape and / or a fixing tool such as a clip 14
After fixing with, the coated body in which the convex surface of the mold 12 is wrapped with the sheet body 11 is 100 to 600 ° C., preferably 1
It is heated to a temperature of 50 to 500 ° C., more preferably 200 to 450 ° C. to evaporate and remove volatile components such as a solvent from the sheet body and shrink the sheet body toward the convex surface of the mold. Then, on the entire convex surface of the mold 12,
The solvent-removed and shrunk sheet body 11 is brought into close contact as shown in FIG. 3, and finally, the fixing tool 14 such as an adhesive tape and a clip is removed, and then the mold 12 is removed,
A dish-shaped (or box-shaped, tubular-shaped, etc.) aromatic polyimide sheet or molded body 15 having at least a concave portion (or convex portion) having a shape corresponding to the convex surface of the mold 12 as shown in FIG. obtain.

The fixing of the edge portion of the sheet body coated on the mold as described above is not limited to the fixing method described above, and when the coating body in which the mold is wrapped in the sheet body is heated. Any method may be used as long as it is possible to prevent the edge portion of the sheet body from shifting and coming off with respect to the contracting force of the sheet body. For example, the mold 1
The edge portions of the sheet body 11 enclosing 2 are squeezed or folded and overlapped with each other to bond the sheet bodies to each other or to fix the sheet bodies with a heat-resistant adhesive tape, a clip, and / or the edge portions of the sheet body. It is preferable to fix the above to the mold itself with various fixing tools such as a heat-resistant adhesive tape (including an adhesive tape) or clips at a plurality of places over the whole.

In the production method of the present invention, after coating the mold with the sheet body as described above, when heating the coated body at a high temperature,
First, heating is performed while raising the temperature from about 100 ° C. to 300 ° C. in about 0.5 to 5 hours, and finally, the maximum temperature of about 250 ° C. or higher, particularly preferably 300 to 500 ° C. is set to about 0.1 to 0.1 ° C.
It is preferable to maintain and heat for about 5 hours. Further, the heating temperature of the above-mentioned coated body is such that when a sheet body composed of an aromatic polyamic acid and an organic polar solvent is used as the sheet body, the amide-acid bond of the polyamic acid is removed together with the evaporation removal of the organic polar solvent. Since it is necessary to perform imide cyclization (dehydration reaction) to convert the polyamic acid into a polyimide, it is preferable that the temperature is relatively high (for example, 250 to 500 ° C.).

As shown in FIG. 2, the mold is not particularly limited in its shape as long as it has a convex surface, and if necessary, in order to reduce the weight, a box shape, a cylindrical shape. It is preferable that the sheet has a hollow shape like a dish, and if the hollow surface has a large number of through holes (exhaust holes) in the convex surface, the sheet covered with the mold. It is preferred because the aforementioned evaporation of the organic polar solvent from the body is carried out on both sides of the coated sheet body.

In the manufacturing method of the present invention, in the case of the deep-bottomed box-shaped mold 22 as shown in FIG. 6, the mold 22 is wrapped with the sheet body 21 as shown in FIGS. 7 and 8. The sheet body 21 is covered with the sheet body 21 by fixing the upper edge portion of the sheet body 21 to the upper edge portion of the die 22 using a fixing tool 24, and joining the two edge portions of the sheet body with the sheet body 21. Form the body. Then, the coated body may be heated in a heating furnace or the like to produce a box-shaped container-shaped polyimide sheet molded body 25 as shown in FIG.

[Examples] Hereinafter, the production method of the present invention will be described in more detail with reference to Examples.

In the examples, the logarithmic viscosity is measured at a temperature of 30 ° C., the polymer concentration is 0.5 g / 100 ml solvent,
Further, it is a value calculated by the following equation, measured under the measurement conditions in which the solvent is dimethylacetamide.

Example 1 100 parts by weight of an aromatic polyamic acid (logarithmic viscosity: 3.5) obtained from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and paraphenylenediamine, and dimethyl Using a sheet body (thickness: 85 μm) composed of 80 parts by weight of acetoamide, the mold shown in FIG. 1 (vertical length: 30 cm, horizontal length: 20 cm, height: 8)
cm) and the sheet body is superposed on the side of the convex surface of the die to closely enclose the convex surface of the mold, and the edge portion of the sheet body is provided with a corner portion as shown in FIG. Etc., and then fix the edge and other edges to the edge of the mold with a fixture (using clips, adhesive tape, etc.), and cover as closely as possible with the sheet body. A coating consisting of the above-mentioned mold was formed.

The coating is placed in a heating oven and first heated from 100 ° C to 45 ° C.
While heating to 0 ° C. in about 1 hour while heating, the coated body is left at a temperature of 450 ° C. for about 30 minutes to evaporate and remove the organic polar solvent from the sheet body and to imidize the polymer. Then, the sheet body is contracted toward the convex surface of the mold to be in close contact with it, then the fixture is removed from the covering body, and the mold is further removed to obtain a thickness of 50 μm as shown in FIG. A dish-shaped polyimide sheet molded body formed from the aromatic polyimide sheet was prepared.

The above-mentioned dish-shaped sheet molded body has a temperature of 200 ° C. of about 10
The heat resistance test of standing for 5 hours was repeated 5 times, but no change in appearance such as shape was observed in the dish-shaped sheet molded body. Further, the polyimide sheet forming the dish-shaped sheet-formed product exhibits mechanical physical property values as shown in Table 1 below with respect to the above-mentioned thermal history, and the mechanical properties are almost unchanged. confirmed.

Note: The measurement was performed according to ASTM-D-882.

[Effects of the Present Invention] A method for producing a polyimide sheet molded article of the present invention comprises a container-shaped polyimide sheet molded article comprising a heat-resistant aromatic polyimide sheet and having a concave portion, an aromatic polyamic acid or a polyimide and an organic polar group. It is a novel method that can be industrially produced with good reproducibility from a sheet body composed of a solvent.

The polyimide sheet molded body obtained by the production method of the present invention is an aromatic polyimide sheet molded body that is formed in a container shape having a recess substantially without using an adhesive, and thus has high heat resistance and Has excellent chemical resistance. Therefore, there is an advantage that it can be repeatedly used as a protective container or a protective cover for electric / electronic parts, electric / electronic devices that require severe heat treatment or chemical treatment.

[Brief description of drawings]

1 and 2 are perspective views showing steps of an example of the manufacturing method of the present invention. FIG. 3 is an elevation sectional view taken along the line II of FIG. 4 to 5 are perspective views showing another embodiment of the polyimide sheet molded body obtained by the manufacturing method of the present invention. 6 to 7 are perspective views illustrating a part of steps of another manufacturing method of the present invention. FIG. 8 is a sectional elevation view taken along the line II of FIG. FIG. 9 is a perspective view showing a polyimide sheet molded body obtained by the steps of FIGS. 11, 21: Sheet body, 12, 22: Mold, 13: Stacked portion of sheet body, 14, 24: Fixture, 15, 2
5: Molded polyimide sheet

Claims (1)

[Claims] 1. A sheet body comprising 100 parts by weight of an aromatic polyamic acid or aromatic polyimide and 10 to 150 parts by weight of an organic polar solvent is used, and a mold having a convex surface on at least one side can be used as the sheet body. 100 to 600, the convex surface of the mold is wrapped with the sheet body after the sheet body is tightly wrapped and the edge portion of the sheet body is fixed.
The solvent is removed from the sheet body by heating to a temperature of ℃ to evaporate and remove the solvent from the sheet body and shrink the sheet body toward the convex surface of the die. The polyimide sheet molded body characterized in that an aromatic polyimide sheet molded body having a concave portion having a shape corresponding to the convex surface of the mold is obtained by finally contacting the contracted sheet body and finally removing the mold. Manufacturing method.