JPH0820060A - Method for producing polyetherimide film - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method for producing a polyetherimide film which has a very small amount of foreign matters and gels, foaming, air running, and generation of wrinkle-free wrinkle stripes to obtain a film having a uniform thickness and good appearance. . [Structure] Polyetherimide having a water content of 100 ppm or less is filtered by a foreign matter removing filter having a filtration accuracy of 20 to 50 μm, melt-extruded into a film on a cast roll at a temperature of 140 to 220 ° C., and extruded by a nip roll having an elastic surface. A method for producing a polyetherimide film, characterized in that the film is pressed onto a cast roll.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyetherimide (hereinafter referred to as PEI) film which is used as a label, tape, masking material for electrical insulation and heat resistance.

[0002]

2. Description of the Related Art PEI film products have been empirically used by extruding a dry raw material with a general extruder, fixing the film on a plating roll with an air knife or the like, and taking it out. However, in such a method, the thickness distribution lacks uniformity, various defects such as foreign matter are mixed, and only a product having a low commercial value can be obtained.

Further, the extruded film has poor slipperiness, and it is difficult to wind it without wrinkles, and there is a problem that the slipperiness is bad in using the film.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and the PEI film does not contain air, streaks, foreign matters, etc., and has a uniform thickness and good slipperiness. It is an object of the present invention to provide a method for producing a PEI film capable of obtaining a film having a thickness suitable for various uses.

[0005]

Means for Solving the Problems The present invention is intended to solve the above problems, and its gist is to filter a polyetherimide having a water content of 100 ppm or less with a foreign matter removing filter having a filtration accuracy of 20 to 50 μm, and A method for producing a polyetherimide film, characterized in that the film is melt-extruded on a cast roll at 140 to 220 ° C., and the film extruded by a nip roll having an elastic surface is pressed onto the cast roll, and the cast roll has an embossed surface. And has a content of 0.1 in the polyetherimide film.
A method for producing a polyetherimide film, which comprises forming an emboss having a surface roughness of 0.5 μm.

The present invention will be described in more detail below.

PE used in the manufacturing method of the present invention
It is important that I is in a dry state with the raw material water content of 100 ppm or less.

If the water content of the raw material exceeds 100 ppm, the film foams and bubbles are generated, so that a film having a good appearance cannot be obtained, which is not preferable.

The above PEI raw material has a filtration accuracy of 20 to 50 μm.
m through a foreign matter removing filter, and melt-extruded into a film. If the filtration accuracy of the filter is less than 20 μm, the backup pressure becomes large, the productivity does not increase, and the extruder may be damaged, which is not preferable.

Further, if the filtration accuracy is 50 μm or more, foreign matter cannot be removed, which is not preferable, and the above range is preferable.

Then, the melt-extruded extrudate has a temperature of 1
The film is melt extruded on a cast roll at 40 ° C to 220 ° C and cooled.

If the temperature of the cast roll is less than 140 ° C., the film is curled and cannot be used, which is not preferable. It is not preferable because it deteriorates product quality.

Then, the film melt-extruded to the cast roll is nipped on the cast roll by a nip roll having an elastic surface such as a rubber roll, and the PEI film is pressed onto the cast roll. By pressing the PEI film under pressure with this nip roll, it is possible to prevent excessive pulling of the central portion, and to prevent wrinkle-like unevenness occurring in both ends of the film. Further, it is desirable to form an embossed surface on the cast roll and to form an embossment of 0.1 to 0.5 μm on the PEI film surface.

If the surface roughness is less than 0.1 μm, there is no sliding effect, and if the surface roughness exceeds 0.5 μm, the transparency is lowered and the physical properties are not preferable, and the above range is preferable.

The present invention has been completed through the following experiments 1 to 3. Experiment 1 A PEI raw material having a raw material water content shown below is extruded at a temperature of 360 to 360
The film was extruded at 380 ° C. to form a film having a thickness of 25 to 125 μ, and the film surface condition was observed. The results are shown in Table 1.

[0016]

[Table 1] Experiment 2 A leak disc filter made of Dynaloy having different filtration accuracy was used, and extrusion molding was performed at an extrusion temperature of 360 to 380 ° C.
A film having a thickness of 25 to 125 μm was prepared.

20 × 20 cm of the obtained PEI film
The state of foreign matters and gel within the area of is shown in Table 2.

[0018]

[Table 2] When the filtration accuracy was 15μ, the number of foreign matters and gels was extremely small, but the backup pressure was large and the productivity was poor. Experiment 3 A PEI raw material having a water content of 98 ppm was filtered through a foreign matter removal filter having a filtration accuracy of 25 μm, melt-extruded into a film shape on a cast roll whose temperature was changed between 135 ° C. and 290 ° C., and the film was pressed by a rubber roll. I made a film.

The appearance of the film at each casting roll temperature is shown in Table 3.

[0020]

[Table 3] It can be seen that when the cast roll temperature is 140 to 220 ° C., the film appearance gives good results.

[0021]

EXAMPLES The present invention will be described below based on examples. Example 1 A PEI raw material having a raw material water content of 98 ppm has a filtration accuracy of 25 μm.
It was filtered by a foreign matter removing filter of No. 1 and melt-extruded into a film on a cast roll at a temperature of 180 ° C.

Then, the film extruded by the nip roll made of a rubber roll was pressed onto the cast roll to obtain a PEI film having a thickness of 100 μm.

The obtained film had a uniform thickness, had very few foreign matters and gels, had no appearance of foaming, air running or wrinkle-like wrinkles, and had a good appearance. Example 2 Under the same conditions as in Example 1, melt-extruded onto a cast roll having an embossed surface, pressed by a rubber roll in the same manner as in Example 1, and having a thickness of 12 having a surface roughness of 0.3 μm.
0 μ of PEI film was obtained.

The obtained film had a uniform thickness, had very few foreign matters and gels, foamed, had no air running, and had excellent transparency. Further, it had better slipperiness than the film of Example 1 and could be wound up without wrinkles.

[0025]

As described above, the present invention has a water content of 100.
Filtering accuracy of PEI film of ppm or less 20 to 50 μm
Filtered by the foreign matter removal filter, and the temperature is 140 ~ 220 ℃
The film is melt-extruded on a cast roll, and the film extruded by a nip roll having an elastic surface is pressed against the cast roll, so that there are very few foreign matters and gels, and foaming, air running, and the generation of wrinkled stripes There is no appearance, and a PEI film having a very uniform thickness can be obtained.

Further, the PEI film melt-extruded as described above is P-cast by a cast roll having an embossed surface.
By forming an emboss with a surface roughness of 0.1 to 0.5 μm on the EI film, a film having good transparency and good slipperiness according to various uses can be obtained.

Claims (2)

[Claims] 1. A nip roll having an elastic surface, which is obtained by filtering polyetherimide having a water content of 100 ppm or less with a foreign matter removing filter having a filtration accuracy of 20 to 50 μm and melt-extruding it into a film on a cast roll at a temperature of 140 to 220 ° C. A method for producing a polyetherimide film, which comprises press-contacting the film extruded with a cast roll. 2. The cast roll has an embossed surface,
The polyetherimide film according to claim 1 has 0.1 to
A method for producing a polyetherimide film, which comprises forming an emboss having a surface roughness of 0.5 μm.