JPH0522568B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a method for forming a polycyanoarylether film having excellent heat resistance, mechanical strength, and transparency. [Technical background of the invention and its problems] Polycyanoaryl ether is disclosed in
No. 14270 and Japanese Unexamined Patent Publication No. 59-206433 disclose various structures. It is known that the polycyanoaryl ethers disclosed in these publications are crystalline polymers with excellent heat resistance. In general, films with heat resistance and transparency are
It is expected to have a wide range of applications in various industrial fields, and mass production is desired. However, when a film is formed from the above-mentioned polycyanoaryl ether by a conventional method, although the film obtained has heat resistance, it has generally not been transparent. Therefore, it is desired to develop a method for forming a transparent film from polycyanoaryl ether having heat resistance. [Object of the invention] The present invention meets the above-mentioned demands,
The purpose of the present invention is to provide a method for forming a polycyanoaryl ether film that has excellent transparency, heat resistance, and mechanical strength. [Summary of the Invention] The method for molding the polycyanoarylether film of the present invention is as follows: A polycyanoaryl ether containing 90 mol% or more of repeating units represented by and having a number average molecular weight of 25,000 to 50,000 is extruded at 360 to 460°C, and then rapidly cooled to 150°C or less. do. First, polycyanoaryl ether having the above-mentioned characteristics is used as a film material in the present invention. In such polycyanoaryl ether, the content of repeating units represented by formula () is 90
If it is less than mol%, heat resistance and mechanical strength will decrease. In addition to the repeating unit shown by the formula (), polycyanoaryl ether used as a film material has the following formula: (In the formula, Ar is

It may be a copolymer containing less than 10 mol% of at least one type of repeating unit represented by the following formula (representing an arylene group other than the formula). As Ar in formula (), for example,

【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] can be given. Next, the above-mentioned number average molecular weight can be determined by dissolving this polycyanoaryl ether in N-methylpyrrolidone to a concentration of 70 mg/dl, using high-temperature gel permeation chromatography (measuring temperature: 135 mg/dl). ℃) refers to the number average molecular weight in terms of polystyrene. If the number average molecular weight is less than 25,000, a film can be obtained by extrusion molding as described below, but the strength of the film will be too low to be practical. On the other hand, if the number average molecular weight exceeds 50,000, the melt viscosity becomes high when the polymer is melted, making extrusion molding difficult. The number average molecular weight is adjusted by setting the reaction conditions (temperature, time) during the polymerization reaction to predetermined values, or by adding a predetermined amount of a molecular weight regulator. In the latter case, the molecular weight modifier has the following formula: (In the formula, R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group, an aralkyl group, or a cyano group.) It is preferable to use a monovalent phenol represented by, for example, cumylphenol. , phenylphenol, p
-tert-butylphenol is preferred. In the polycyanoaryl ether having the above characteristics, the repeating units represented by the formula () are linear, or the repeating units represented by the formula () and () are mutually disordered or ordered. It is composed of a linear chain connected to each other, and its terminal ends are -H, -X,

【formula】

【formula】

[Formula] (where R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group, or an aralkyl group,
X represents a halogen atom). The above-mentioned polycyanoaryl ether can be produced, for example, as follows. That is, after polymerizing dihalogenobenzonitrile and an alkali metal salt of 4,4'-biphenol and, if necessary, an alkali metal salt of another divalent phenol in the presence of a solvent, the mixture is treated with water or alcohol. This is the way to do it. The film forming method of the present invention is carried out as follows using the above-mentioned polycyanoaryl ether. That is, first, the above-mentioned polycyanoaryl ether is supplied to a melt extruder and melt-treated. The film is then extruded through a die of an extruder and rapidly cooled. When the T-die method (cast method) is applied as the extrusion method, the molten polycyanoaryl ether is extruded from the die of the extruder into a film, and the extruded film is immediately introduced onto the surface of a cooling roll or into water. Cool quickly. Also,
An inflation method may be applied as the extrusion method. In the present invention, the extrusion temperature is required to be 360 to 460°C in the extrusion molding described above. 360℃
If it is less than 460°C, film forming properties are poor and a homogeneous film cannot be obtained, and if it exceeds 460°C, discoloration of the film or foaming inside the film occurs, making it impossible to obtain a good quality film. Preferably it is 370-410°C. Further, the temperature during cooling of the film needs to be 150°C or less. If the temperature exceeds 150°C, the polycyanoaryl ether crystallizes, resulting in a decrease in the transparency of the film, or in the film becoming cloudy or wrinkled. [Examples of the invention] Example 1 In an autoclave with an internal volume of 5, 215 g (1.25 mol) of 2,6-dichlorobenzonitrile and 4,
Add 232.5 g (1.25 mol) of 4'-biphenol, 207 g (1.5 mol) of potassium carbonate, 2.5 g of sulfolane, and 1 mol of toluene, and while blowing argon gas,
The reaction was carried out at 160°C for 1.5 hours, and then heated to 200°C for 2 hours. After the reaction was completed, a large amount of water was injected to obtain polycyanoaryl ether powder. The obtained polymer was washed 5 times with 5 portions of hot water and 2 times with 5 portions of methanol and dried to obtain 340 g of polycyanoaryl ether (yield: 95
%) was obtained. Here, a high temperature gel permeation chromatography method (measured value
The number average molecular weight in terms of polystyrene (135°C) was measured, and the results are shown in the table. In addition, when we investigated the thermal properties of this polymer, we found that
It was confirmed that it had a glass transition temperature of 216°C, a melting point of 355°C, and a thermal decomposition onset temperature (in air) of 520°C, which was sufficient for practical use. Next, the solvent resistance of this polymer was examined, and it was found to be insoluble in the following solvents: acetone, ethanol, toluene, methylene chloride, and chloroform. Furthermore, after exposing this polymer to the flame of a lighter for 10 seconds, when the flame was moved away, the flame quickly extinguished, and no melt dripping was observed, indicating that the flame retardance was good. Next, this polymer powder was poured into a cylinder with a diameter of 30 mm.
mm, ratio of cylinder total length (L) to diameter (D) L/D = 25,
Supplied to a melt extruder with a screw rotation speed of 60 rpm,
Cylinder temperature 410℃, die temperature (extrusion temperature) 400℃
Under these conditions, a film having a width of 300 mm and a wall thickness of 100 μm was extruded, and the extruded film was immediately electrostatically cast onto a cooling roll having a surface temperature (cooling temperature) of 70° C. to obtain a transparent film. The transparency of the film was determined by measuring the light transmittance at a wavelength of 480 nm for a film with a thickness of 100 μm. The mechanical properties of the obtained film, ie, breaking strength, elongation, and elastic modulus, were measured and the results are shown in the table. Examples 2 to 4 Example 1 was repeated except that polycyanoaryl ether having the number average molecular weight as shown in the table was produced in the same manner as in Example 1 by extending the polymerization reaction time at 200°C in Example 1. A film was formed in the same manner as above. The heat resistance, flame retardance and solvent resistance of the obtained polymer were the same as in Example 1, the transparency of the obtained film was good as in Example 1, and the mechanical properties of the film were as shown in Table 1. It exhibited the following characteristics. Comparative Example 1 By shortening the polymerization reaction time at 200° C. in Example 1, a polycyanoaryl ether with a number average molecular weight of 15,000 was obtained. Next, this polymer was extrusion molded in the same manner as in Example 1, but the resulting film was so brittle that it was impossible to measure its mechanical properties. Comparative Example 2 A polycyanoaryl ether having a number average molecular weight of 73,000 was obtained by extending the polymerization reaction time at 200°C in Example 1 further than in Examples 2 to 5. Next, extrusion molding of this polymer was attempted in the same manner as in Example 1, but the melt viscosity of the polymer was too high to form a film. Examples 5 and 6 Using polycyanoaryl ether with a number average molecular weight of 40,000 obtained in Example 2, the extrusion temperature was 370°C in Example 5 and 430°C in Example 6, and the cooling temperature was 120°C in both cases. Extrusion molding was carried out in the same manner as in Example 1, except that the temperature was changed to .degree. The film production was good in both cases, and the physical properties of the film were the same as in Example 2. Comparative Examples 3 and 4 Using the polycyanoaryl ether with a number average molecular weight of 40,000 obtained in Example 2, the extrusion temperature was 350°C for Comparative Example 3 and 470°C for Comparative Example 4, and in addition, Example 5 Extrusion molding was carried out in the same manner as in , 6. In the film obtained in Comparative Example 3, the measured values of mechanical properties differ depending on each location of the film, and there are good locations and poor locations regarding transparency.
Variations in physical properties were observed on the same film, making the film poor in practical use. On the other hand, the film obtained in Comparative Example 4 had bubbles and gel portions, and was poor in practical use. Comparative Example 5 Using polycyanoaryl ether with a number average molecular weight of 40,000 obtained in Example 2, the cooling temperature was
Extrusion molding was carried out in the same manner as in Example 1 except that the temperature was 210°C. The resulting film did not have sufficient transparency. The above results are shown in the table.

[Table] [Effects of the Invention] As is clear from the examples of the invention, if a polycyanoarylether film is produced by the method of the present invention, it will have excellent transparency, mechanical strength, and heat resistance. An excellent film can be obtained. Therefore, the film obtained by the method of the present invention is useful as a film for various industries (for example, electronic/electrical equipment, machinery) that require transparency, heat resistance, and mechanical strength, and as a film for household use.

Claims (1)

[Claims] Primary formula: A polycyanoaryl ether containing 90 mol% or more of repeating units represented by and having a number average molecular weight of 25,000 to 50,000 is extruded at 360 to 460°C, and then rapidly cooled to 150°C or less. A method for forming polycyanoaryl ether film.