JPH07178804A - Production of stretched polyimide film - Google Patents

Abstract

PURPOSE:To obtain a stretched polyimide film stable in melt extrusion molding over a long period of time and capable of being uniformly stretched by stretching a film obtained from a compsn. prepared by compounding a specific amt. of polyether ether ketone with a thermoplastic polyimide having a specific structure and a specific logarithmic viscosity under specific conditions and thermally fixing the stretched film. CONSTITUTION:A resin compsn. consisting of 50-97 pts.wt. of (A) thermoplastic polyimide having a repeated structural unit represented by formula I and a logarithmic viscosity of 0.4-0.6dl/g and 50-3 pts.wt. of polyether ether ketone with a melt flow index of 1-5g/10min is molded in a molten state to obtain a non-stretched film. Next, this non-stretched film is stretched by 1.5-10 times in one direction or two directions crossing at a right angle at 230-300 deg.C and thermally fixed within a temp. range of 250 deg.C below the m.p. of the film. By this method, even when polyimide having a high melt viscosity is used, the melt molding of the nonstretched film can be stabilized over a long period of time.

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 polyimide-based stretched film containing a thermoplastic polyimide having a specific structure and a specific amount of polyetheretherketone. More specifically, the present invention relates to a method for producing a polyimide-based stretched film capable of stably performing both melt molding and stretching of a film for a long period of time and producing a stretched film that has been uniformly stretched.

[0002]

Aromatic polyimides have excellent heat resistance,
Since it has mechanical properties, chemical properties, and environmental resistance properties, it is widely used in industrial fields such as the electric and electronic industries, the aircraft industry, and the nuclear industry. 2. Description of the Related Art In recent years, there have been proposed a molded product of thermoplastic polyimide which is capable of melt molding such as extrusion molding and injection molding and is excellent in cost performance, and a manufacturing method thereof. For example, Japanese Patent Laid-Open No. 3-205432
In the official gazette, the formula (1) [Chemical formula 3]

[0003]

[Chemical 3] A thermoplastic polyimide film having a repeating structural unit represented by the formula (1) is stretched at a temperature of 230 to 320 ° C. in one direction or two directions perpendicular to each other by 1.5 to 10 times, and then 250 ° C. or more of the film under tension. A method for producing a stretched polyimide film which is heat-set at a temperature below the melting point is disclosed. However, the stretched film obtained by this method is not always a sufficiently uniformly stretched film, and there are cases in which the degree of stretching varies, and it cannot be said to be a sufficiently satisfactory method.

As a method for solving this problem, for example,
JP-A-4-328125 discloses a mixed solvent of phenol and p-chlorophenol having a repeating structural unit represented by the above formula (1) [Chemical Formula 3] and having a volume ratio of 9: 1. The logarithmic viscosity of the dissolved solution is 0.5 at 30 ° C.
A polyimide stretched film obtained by stretching an unstretched film having a density of up to 0.9 dl / g is disclosed. However, the stretched film is sufficiently satisfactory in terms of uniform stretchability, but since it is a polyimide having a high melt viscosity, there is a problem in long-term extrusion stability of an unstretched film. For example, when a non-stretched film is manufactured by continuously performing melt extrusion molding for 5 hours or more using a large-scale molding machine, there may be spots or the power consumption of the extruder screw drive motor may fluctuate. However, there is a drawback that the extrusion stability over a long period of time is lacking.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a method for producing a stretched polyimide film capable of stable melt extrusion molding for a long period of time and capable of uniform stretching. is there.

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventors have found that a thermoplastic polyimide having a specific structure has a specific amount of polyether ether ketone within a range that does not impair the heat resistance. The present invention has been completed by finding that the inclusion of the compound enables stable melt molding and uniform stretching for a long period of time.

That is, the present invention is based on the formula (1)

[0008]

[Chemical 4] A thermoplastic polyimide 50 having a repeating structural unit represented by and having an inherent viscosity of 0.4 to 0.6 dl / g.
~ 97 parts by weight and a melt flow index of 1
The resin composition containing 50 to 3 parts by weight of polyetheretherketone of about 5 g / 10 min is melt-molded to form an unstretched film.
Of a polyimide-based stretched film, characterized in that it is stretched 1.5 to 10 times in one direction or two directions at right angles at a temperature of up to 300 ° C., and is further heat-set at a temperature of 250 ° C. or higher and below the melting point of the film. It is a manufacturing method.

A feature of the present invention is that a raw material is a resin composition obtained by mixing a thermoplastic polyimide having a specific structure with a specific amount of polyether ether ketone. By adopting such a constitution, even when a polyimide having a high melt viscosity is used, melt molding of an unstretched film can be stabilized for a long period of time, and uniform stretching is also possible. The logarithmic viscosities of the polyimide powder, the unstretched film and the stretched film in the present invention were determined by dissolving a sample in a mixed solvent of 9 parts by volume of phenol and 1 part by volume of p-chlorophenol (concentration: 0.5 g / d).
l) and the viscosity of the mixed solvent are measured at 30 ° C. using an Ubbelohde viscometer, respectively,
[Equation 1]

[0010]

[Equation 1] [In the formula, t is the drop time of the solution (sec), t ₀ is the drop time of the mixed solvent (sec), and C is the solution concentration (g / dl)]
The value calculated by Further, the melt flow index in the present invention is a value measured under the conditions of 360 ° C. and a load of 2.16 kg according to the method specified in ASTM-D1238.

The present invention will be described in detail below. First, the resin composition used in the present invention will be described.
The polyimide used in the present invention is basically pyromellitic dianhydride and 4,4, -bis (3-aminophenoxy).
It is a thermoplastic polyimide having a repeating structural unit represented by the general formula (1) [Chemical Formula 4] obtained by polymerizing biphenyl, polyamic acid, and imidization by dehydration condensation. This polyimide contains 20 mol of other tetracarboxylic dianhydride other than the above-mentioned pyromellitic dianhydride used as an acid dianhydride, based on the total amount of tetracarboxylic dianhydride including pyromellitic dianhydride. %, Preferably less than 10 mol%, more preferably less than 5 mol%.

Examples of such tetracarboxylic acid dianhydrides include butanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, 1,2,3,4-
Benzenetetracarboxylic dianhydride, 2,3,6,7-
Naphthalenetetracarboxylic dianhydride, 1,4,5,8
-Naphthalenetetracarboxylic dianhydride, 1,2,5
6-naphthalenetetracarboxylic dianhydride, 3,4
9,10-perylenetetracarboxylic dianhydride, 2,
3,6,7-anthracene tetracarboxylic dianhydride,
1,2,7,8-phenanthrenetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride , 3,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic acid dianhydride, 2,2-bis (3,4-dicarboxyl Phenyl) propane dianhydride,
2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, 2,2-bis (3,4
-Dicarboxyphenyl) -1,1,1,3,3,3-
Hexafluoropropane dianhydride, 2,2-bis (3,4
-Dicarboxyphenyl) -1,1,1,3,3,3-
Hexachloropropane dianhydride, 1,1-bis (2,3
-Dicarboxyphenyl) ethane dianhydride, bis (2,2
3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride,
4,4 '-(p-phenylenedioxy) diphthalic acid dianhydride, 4,4'-(m-phenylenedioxy) diphthalic acid dianhydride, 4,4'-diphenylsulfide dioxybis (4-phthalate) Acid) dianhydride, 4,4'-diphenylsulfonedioxybis (4-phthalic acid) dianhydride, methylenebis- (4-phenyleneoxy-4-phthalic acid) dianhydride, ethylidenebis- (4-phenyleneoxy) −
4-phthalic acid) dianhydride, isopropylidene bis-
(4-phenyleneoxy-4-phthalic acid) dianhydride,
Hexafluoroisopropylidene bis- (4-phenyleneoxy-4-phthalic acid) dianhydride and the like can be mentioned.

The polyimide used in the present invention contains, in addition to the above 4,4'-bis (3-aminophenoxy) biphenyl used as an aromatic diamine, another aromatic diamine.
It may be contained in an amount of less than 20 mol%, preferably less than 10 mol%, more preferably less than 5 mol%, based on the total amount of diamines including 4'-bis (3-aminophenoxy) biphenyl.

Examples of such diamines include bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl]. Ketone, 4,4'-bis (3-aminophenoxy)
Biphenyl, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3
-Hexafluoropropane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 4,4 '
-Diaminodiphenylmethane, 1,1-di (p-aminophenyl) ethane, 2,2-di (p-aminophenyl)
Propane, 2,2-di (p-aminophenyl) -1,
1,1,3,3,3-hexafluoropropane and the like can be mentioned.

The molecular weight of the polymer affects the stretchability of the unstretched film. If the molecular weight is too low, uniform stretching cannot be achieved, and variations in the thickness and strength of the stretched film become large, which is not preferable. On the other hand, if the molecular weight is too high, the melt viscosity becomes so high that stable melt extrusion for a long period becomes difficult, which is not preferable.

In consideration of the above point, for example, when the molecular weight is represented by the solution viscosity, the above formula (1) used in the present invention is used.
The thermoplastic polyimide having the repeating structural unit represented by [Chemical Formula 4] has a logarithmic viscosity at 30 ° C. of 0.4 to 0.
It is preferably in the range of 6 dl / g. More preferably, it is 0.4 to 0.5 dl / g.

In order to obtain a thermoplastic polyimide having a repeating structural unit represented by the above formula (1) [Chemical Formula 4] within the above viscosity range, the total amount of tetracarboxylic dianhydride including pyromellitic dianhydride is required. And the molar ratio of the total amount of the aromatic diamine containing 4,4′-bis (3-aminophenoxy) biphenyl is 1: 0.93 to 0.98, or 0.9.
It is preferably in the range of 3 to 0.98 to 1, more preferably 1 to 0.94 to 0.96, or 0.94 to
The range is 0.96 to 1. Further, it is preferable to add a dicarboxylic acid anhydride or a monoamine in accordance with the reaction ratio of the both to react.

Specifically, when the total number of moles of tetracarboxylic dianhydride containing pyromellitic dianhydride is larger than the total number of moles of diamine containing 4,4'-bis (3-aminophenoxy) biphenyl. Is the following equation (2) [Equation 2]

[0019]

[Equation 2] (In the formula, A is the total number of moles of tetracarboxylic dianhydride including pyromellitic dianhydride, and B is 4,4′-bis (3-
It is preferable to add the monoamine in an amount within the range calculated by the total number of moles of diamine containing aminophenoxy) biphenyl, C represents the number of moles of monoamine, and A ≧ B.

The total number of moles of tetracarboxylic dianhydride including pyromellitic dianhydride is 4,4'-bis (3
When the amount is less than the total number of moles of the diamine containing -aminophenoxy) biphenyl, the following numerical formula (3) [Equation 3]

[0021]

[Equation 3] (In the formula, A is the total number of moles of tetracarboxylic dianhydride including pyromellitic dianhydride, and B is 4,4′-bis (3-
The total number of moles of diamine containing aminophenoxy) biphenyl, D is the number of moles of dicarboxylic acid anhydride, and it is preferable to add the amount of dicarboxylic acid anhydride in the range calculated by B ≧ A.

Examples of the dicarboxylic acid anhydride preferably used in the present invention include phthalic anhydride, 2,3-benzophenone dicarboxylic acid anhydride, 3,4-benzophenone dicarboxylic acid anhydride and 2,3-dicarboxyphenylphenyl ether anhydride. Substance, 3,4-dicarboxyphenyl phenyl ether anhydride, 2,3-biphenyl dicarboxylic acid anhydride, 3,4-biphenyl dicarboxylic acid anhydride,
2,3-dicarboxyphenylphenyl sulfone anhydride, 3,4-dicarboxyphenylphenyl sulfone anhydride, 2,3-dicarboxyphenylphenyl sulfide anhydride, 3,4-dicarboxyphenylphenyl sulfide anhydride, 1, 2-naphthalenedicarboxylic acid anhydride, 2,3-naphthalenedicarboxylic acid anhydride, 1,8-
Examples thereof include naphthalene dicarboxylic acid anhydride, 1,2-anthracene dicarboxylic acid anhydride, 2,3-anthracene dicarboxylic acid anhydride, and 1,9-anthracene dicarboxylic acid anhydride.

As the monoamine preferably used in the present invention, propylamine, butylamine, hexylamine, octylamine, cyclopentylamine, cyclohexylamine, aniline, benzylamine, o-toluidine, m-toluidine, p-toluidine, o- Anisyridine, m-anisiridine, p-anisiridine, xylidine, 1-aminonaphthalene, 2-aminonaphthalene and the like can be mentioned.

The polyether ether ketone used in the present invention has a compound represented by the formula (2):

[0025]

[Chemical 5] It is a thermoplastic resin having a repeating structural unit represented by: Among these polyether ether ketones, the melt flow index measured by the above-mentioned method is 1 to 5 g / 1 in consideration of the long-term extrusion stability of the unstretched film.
Thermoplastic polyetheretherketone in the range of 0 min is preferably used. A typical commercially available polyetheretherketone having such characteristics is VICTREX PEEK 45 manufactured by ICI of England.
0P, VICTREX PEEK 380P, VICT
REX PEEK 150P and the like can be mentioned.

The blending ratio of the polyimide and the polyether ether ketone in the present invention affects the long-term melt extrusion stability and uniform stretchability of the unstretched film, and the heat resistance of the stretched film obtained. Specifically, when a polyimide having a low molecular weight such that uniform stretching cannot be used, the long-term melt extrusion stability of the unstretched film is good when the blending amount of the polyetheretherketone is small, but unstretched. The stretchability of the film tends to decrease. Further, if the blending amount of polyether ether ketone is too large, the heat resistance of the obtained stretched film tends to decrease regardless of the molecular weight of the polyimide. From this viewpoint, the blending ratio of both resins is appropriately selected within the range of 50 to 3 parts by weight of polyether ether ketone with respect to 50 to 97 parts by weight of the polyimide resin. Preferably, 50 to 5 parts by weight of polyether ether ketone is used with respect to 50 to 95 parts by weight of polyimide resin.

The mixing method of both resins is not particularly limited, and a known mixing method is applied. For example, a method of mixing at room temperature or a temperature in the vicinity thereof using a ribbon blender, a Fenschel mixer, a tumbler mixer or the like can be mentioned. Considering the compatibility of both resins, it is desirable to mix both resins in powder form.

The stretched polyimide film of the present invention comprises:
In addition to the above thermoplastic polyimide and polyether ether ketone, other thermoplastic resins, antioxidants, heat stabilizers, lubricants, ultraviolet absorbers, organic and inorganic fillers, etc., which are usually used as additives for thermoplastic resins The additive may be added within a range that does not impair the object of the present invention. When other thermoplastic resin is added, it is preferably less than 5% by weight based on the total weight of the thermoplastic polyimide and polyether ether ketone.

Next, the method for producing the stretched polyimide film of the present invention will be described in detail. The polyimide-based stretched film of the present invention is a resin composition prepared by mixing the above-mentioned polyimide and polyether ether ketone in a specific blending ratio, and an amorphous film is produced by a melt molding method, which is not cast by cooling. It can be obtained by obtaining a stretched film, further stretching it uniaxially or biaxially, and heat-treating it to crystallize it.

In the production of the unstretched film, the both resins mixed in powder form may be directly supplied to a molding machine such as an extruder, or may be preliminarily molded into pellets and then fed into an extruder or the like. It may be supplied to a molding machine. However, from the viewpoint that both resins can be mixed uniformly and the extrusion amount is stable,
It is preferable to preliminarily form a pellet.

As a method of forming into pellets, the mixed powder is dried first preferably in the range of 100 to 250 ° C. to have a water content of less than 200 ppm, and preferably fed to an extruder under a nitrogen atmosphere. And 350-450
To produce pellets by heating and melting at a temperature of ℃, extruding through a strand die and cutting the molten strand extruded from the die while cooling, or cutting the molten strand extruded from the die with a cutter after cooling There is a method.

Based on the above description, the powdery mixture or mixed pellets of both resins is preferably 100 to 2
It is dried in the range of 50 ℃ and its water content is 200ppm.
Less than, preferably supplied to the extruder under a nitrogen atmosphere, heated and melted at a temperature of 350 to 450 ° C., extruded from a slit nozzle, and below the glass transition temperature of the obtained polyimide composition, preferably 150 to 250. C., and more preferably, cooled on a casting roll having a surface temperature of 200 to 240.degree. C. to obtain a polyimide-based unstretched film.

Considering the long-term extrusion stability of the unstretched film and the stretchability described later, the unstretched film preferably has an inherent viscosity in the range of 0.5 to 0.8 dl / g. More preferably 0.53 to 0.8 dl /
It is in the range of g.

Next, the stretching method of the stretched polyimide film of the present invention will be described. The unstretched film obtained as described above is stretched 1.5 to 10 times in one direction or two directions at right angles in the range of 230 to 300 ° C,
Then, it is heat set under tension in a temperature range of 250 ° C. or higher and lower than the melting point of the film. The following method is mentioned as a preferable aspect of a stretching process.

Uniaxial stretching method In the temperature range of 230 to 300 ° C., preferably 250 to 280 ° C., uniaxial orientation is carried out by stretching 1.5 to 4 times in one direction.
Then, it is heat set under tension in a temperature range of 250 ° C. or higher and lower than the melting point of the film. If the stretching temperature is a low temperature below the glass transition point, the elastic modulus is high and uniform stretching becomes difficult, and at a temperature higher than the crystallization start temperature, stretching becomes difficult. Further, if the draw ratio is too low, wrinkles may occur in the film in the subsequent heat treatment step, and it is not preferable that the film tends to lose transparency and become a brittle film, and if the draw ratio is too high, the film is highly oriented during drawing, and at the time of drawing. Inconvenient problems such as tearing may occur, which is not preferable. Considering this point, the stretching temperature and the stretching ratio are preferably in the above ranges. As the stretching means, conventionally known methods such as a stretching method using a pair of rolls, a stretching method using a tenter, and a stretching method by rolling using a roll can be used. The stretching speed during stretching is preferably in the range of 1 to 100,000% / min.
Further, it is preferable to preheat the film before stretching so that it does not crystallize because smooth stretching can be performed. The uniaxially stretched film thus obtained preferably has dimensional stability,
In order to improve the mechanical properties, heat setting is performed under tension or limited shrinkage for 1 to 5000 seconds in a temperature range of 250 ° C or higher and lower than the melting point of the film, more preferably 300 to 370 ° C.

Sequential Biaxial Stretching Method Stretching is carried out in the temperature range of 240 to 290 ° C., preferably 250 to 280 ° C. in one direction by 1.5 to 3.0 times, and then 240 to 280 ° C. in the direction perpendicular to the stretching direction. , Preferably 25
It is biaxially oriented by stretching 1.5 to 3.0 times in one direction in a temperature range of 0 to 280 ° C., and then heat set under tension at a temperature of 250 ° C. or higher and lower than the melting point of the film. If the stretching temperature in the first stage is too low, the stretching stress tends to be high and uniform stretching tends to be difficult, and if it is too high, the film tends to crystallize,
It is not preferable because it tends to be difficult to stretch the second stage. Further, if the stretching ratio is too low, it is not preferable because wrinkles may occur in the subsequent heat treatment step, or the film tends to lose transparency and become a brittle film. Conversely, if it is too high, it is highly oriented during stretching, and the second stage This is not preferable because it causes an inconvenient problem such as breakage during stretching. Considering this point,
The stretching temperature and the stretching ratio of the first stage are preferably in the above ranges. Further, if the stretching temperature in the second stage is too low, stretching is difficult and tearing occurs. On the contrary, if it is too high, problems such as embrittlement of the film and tearing of the film may occur, which are not preferable. Further, it is important to appropriately select the stretching ratio in view of the effect of orientation, prevention of film breakage, and the like. Considering this point, it is preferable that the stretching temperature and the stretching ratio of the second stage are within the above ranges.
The stretching means, stretching speed, preheating time, and heat setting are the same as in the uniaxial stretching method.

Simultaneous biaxial stretching method In the temperature range of 240 to 290 ° C., preferably 250 to 280 ° C., biaxial orientation is carried out by simultaneously stretching at an area ratio of 2 to 10 times in directions perpendicular to each other, and then at 250 ° C. or higher, Heat set under tension at a temperature below the melting point of the film. If the stretching temperature is too low, the stretching stress tends to be high and the stretching tends to be difficult. If the stretching temperature is too high, the film tends to crystallize, loses transparency and becomes brittle, and stretching becomes gradually difficult. Further, if the stretching ratio is too low, it is not preferable because wrinkles may be generated in the subsequent heat treatment step, or the film may lose transparency and become a brittle film. Conversely, if it is too high, inconvenient problems such as tearing during stretching tend to occur. It is not preferable. Considering this point, the stretching temperature and the stretching ratio in the simultaneous biaxial stretching are preferably in the above ranges. The stretching means, stretching speed, preheating time, and heat setting are the same as in the uniaxial stretching method.

The polyimide-based stretched film thus obtained is uniformly stretched and does not impair the heat resistance inherent to polyimide, and is a film for electrical insulation at high temperatures and a base for recording media. It is useful for films and dielectric films.

According to the method of the present invention, when an unstretched film which is an intermediate is produced, the melt extrusion stability is good for a long period of time, so that even if it is continuously extrusion-molded for a long time, no lumps or the like are generated. Moreover, since there is no fluctuation in the extrusion rate (variation in the extruder load), a film with less variation in thickness can be obtained, which is suitable for a method for continuous mass production industrially. Further, when stretching the unstretched film, uniform stretching is possible.

The thickness of the stretched film to which the present invention can be applied is not particularly limited, but the applicable range is preferably 0.
It is a stretched film of about 1 μm or more and less than 5 mm. The polyimide-based stretched film obtained as described above,
The logarithmic viscosity measured by the above method is 0.5 to 0.8 dl
/ G range. Preferably 0.53 to 0.8 dl /
It is g.

[0041]

EXAMPLES The present invention will be described in more detail below with reference to examples. The types of each test method and each sample (polyimide powder, polyether ether ketone powder) used in Examples and Comparative Examples are shown below.

[Test Method] (1) Logarithmic viscosity 0.5 g of a sample was collected, 100 ml of a 9: 1 (volume ratio) mixed solvent of phenol and p-chlorophenol was added, and the mixture was completely dissolved at about 150 ° C. for 30 minutes. Then, the temperature is returned to room temperature, and the viscosity at 30 ° C. is measured using an Ubbelohde viscometer.

(2) Stability of extrusion molding Evaluation of stability of extrusion molding is started from the point of time when melt extrusion molding is continuously performed for 5 hours. Extruder drive motor current fluctuation rate Φ50mm Extruder (made by Ikegai Co., Ltd., cylinder diameter; 50mm, screw shape; full flight, screw diameter; 50mm, L / D = 20, compression ratio = 2.5) Then, the motor current during extrusion molding at a screw rotation speed of 60 rpm and a melt molding temperature of 410 ° C. is continuously recorded for 1 hour, and the current value at 7 points is read every 10 minutes and the difference between the maximum value and the minimum value is averaged. It is divided by the value and shown as a percentage (%). Presence or absence of seeds The number of seeds per 1 m ^{2 of the} obtained unstretched film is counted according to the size of the diameter of the core, and three-stage evaluation (A, B, C) is performed. The evaluation criteria are shown in [Table 1].

[0044]

[Table 1] When the variation rate of the current in the comprehensive evaluation is 5% or less and the evaluation of the spot is A or B, the extrusion stability is good, and the others are bad.

(3) Evaluation of Stretched Film After producing an unstretched film continuously for 5 hours, a sample is taken to evaluate the stretchability, and then the heat resistance (heat shrinkage rate) of the obtained stretched film is evaluated. evaluate. Uniformity of Stretching Unstretched film is cut into squares with a side of 90 mm,
After writing 17 grid lines at intervals of 5 mm in each of the vertical and horizontal directions, a batch type biaxial stretching machine (manufactured by Iwamoto Seisakusho Co., Ltd.) is used to stretch to a predetermined magnification. The distance between the lattices after stretching was measured by measuring 10 pieces each in the longitudinal and lateral directions of the central portion to obtain an average stretching ratio, and the variation rate (standard deviation ÷ average value × 100) from the average value and standard deviation.
%). When the variation rate is within 3%, the stretching uniformity is evaluated as good (comprehensive evaluation). Heat resistance (heat shrinkage rate) The stretched film obtained above is used for JIS C-2318.
The sample is heated at 260 ° C. for 2 hours according to the method specified in 1 above, and the heat shrinkage in the MD direction and the TD direction is measured.
At this time, the variation rate [(standard deviation ÷ average value × 100 (%)] of 5 measurement points is calculated at the same time. Is judged to be defective (comprehensive evaluation).

Production Example 1: Polyimide powder A 20 kg of m-cresol, 4,4'-bis (3-) in a reaction vessel equipped with a stirrer, a reflux condenser and a nitrogen inlet tube.
Aminophenoxy) biphenyl (3684 g, 10.0 mol) was charged, and a slurry-like mixture of 2045 g (9.38 mol) of pyromellitic dianhydride and 2 kg of m-cresol was heated to a temperature of 60 ° C. or higher under a nitrogen atmosphere. The mixture was added in portions taking care not to make it so that 202.8 g (1.364 mol) of phthalic anhydride was further added, and the mixture was stirred for 5 hours. Then, the temperature was raised to 140 ° C. over about 3 hours, the mixture was stirred at 140 ° C. for 2 hours, and then cooled to room temperature over 3 hours. The slurry-like liquid was separated by filtration, washed with 20 kg of methanol and then 20 kg of acetone, and then dried under a nitrogen atmosphere at 100 ° C. for 8 hours and then at 300 ° C. for 4 hours to obtain 5425 g (yield 97%). The polyimide powder A of was obtained. The logarithmic viscosity of this polyimide powder A is 0.42.
Met.

Production Example 2: Polyimide powder B 10 kg of m-cresol, 4,4'-bis (3-) in a reaction vessel equipped with a stirrer, a reflux condenser and a nitrogen inlet tube.
Aminophenoxy) biphenyl (3684 g, 10.0 mol) was charged, and a slurry-like mixture of 2056 g (9.43 mol) of pyromellitic dianhydride and 2 kg of m-cresol was added to the solution at a temperature of 60 ° C or higher under a nitrogen atmosphere. The mixture was added in portions while being careful not to change the content, and then 169.0 g (1.140 mol) of phthalic anhydride was added and the mixture was stirred for 5 hours. Then, the temperature was raised to 140 ° C. over about 3 hours, the mixture was stirred at 140 ° C. for 2 hours, and then cooled to room temperature over 3 hours. The slurry-like liquid was filtered off, washed with 20 kg of methanol and then 20 kg of acetone, and then dried in a nitrogen atmosphere at 100 ° C. for 8 hours and then at 300 ° C. for 4 hours to obtain 5350 g (yield 96%). To obtain polyimide powder B. The logarithmic viscosity of this polyimide powder B is 0.45.
Met.

Production Example 3: Polyimide powder C 10 kg of m-cresol, 4,4'-bis (3-) in a reaction vessel equipped with a stirrer, a reflux condenser and a nitrogen inlet tube.
Aminophenoxy) biphenyl (3684 g, 10.0 mol) was charged, and a slurry-like mixture of 2074 g (9.51 mol) of pyromellitic dianhydride and 2 kg of m-cresol was added to the solution at a temperature of 60 ° C or higher under a nitrogen atmosphere. The mixture was added in portions taking care not to make it so that phthalic anhydride (159.6 g, 1.078 mol) was further added, and the mixture was stirred for 5 hours. Then, the temperature was raised to 140 ° C. over about 3 hours, the mixture was stirred at 140 ° C. for 2 hours, and then cooled to room temperature over 3 hours. The slurry-like liquid was filtered off, washed with 20 kg of methanol and then 20 kg of acetone, and then dried under a nitrogen atmosphere at 100 ° C. for 8 hours and then at 300 ° C. for 4 hours to obtain 5100 g (yield 92%). The polyimide powder C of was obtained. The logarithmic viscosity of this polyimide powder C is 0.49.
Met.

Polyetheretherketone powder PEEK 380P manufactured by ICI was used (hereinafter, P
Called EEK powder).

Examples 1 to 4, Comparative Examples 1 to 4 Polyimide powder A or polyimide powder B and PEEK powder were mixed in a weight ratio shown in [Table 2] or [Table 3], and then 180 ° C. under a nitrogen stream. And dried for 20 hours. Φ40mm bent type twin-screw extruder (made by Ikegai Seisakusho)
The mixture was melted and kneaded at 405 ° C., extruded from a nozzle having a diameter of 3 mm, cooled and solidified, and cut by a strand cutter to obtain pellets having a diameter of about 2 mm and a length of about 3 mm.
The mixed pellets were dried at 150 ° C. for 20 hours in a nitrogen stream (the water content after drying was 50 ppm or less) and fed to a 50 mm extruder (manufactured by Ikegai Seisakusho).
It was heated and melted at 10 ° C., extruded from a slit die having a width of 700 mm (gap: 0.6 mm), and taken out on a roll at 220 ° C. to obtain a polyimide-based unstretched film having a thickness of about 100 μm.

The unstretched film was cut into a square having a side of 90 mm, and then the batch type biaxial stretching machine (manufactured by Iwamoto Seisakusho)
After being preheated for a predetermined time, the film was uniaxially stretched in the length direction (MD) or further biaxially stretched successively in the perpendicular direction (TD) and heat-treated at a predetermined temperature for a predetermined time. The stretching conditions of the film in each Example and Comparative Example are shown in [Table 2] or [Table 3]. The logarithmic viscosity of the unstretched film, the extrusion stability of the unstretched film, the stretching uniformity of the stretched film, and the heat shrinkage were evaluated by the above methods, and the results are shown in [Table 2] or [Table 3].

[0052]

[Table 2]

[0053]

[Table 3]

In the production of the unstretched films in Examples 1 to 4, the fluctuation rate of the current of the screw driving motor of the extruder was 2 or 3%, and the fluctuation rate was small. In addition, the number of spots was rank A, which was small. The inherent viscosity of the unstretched film and the stretched film obtained was in the range of 0.53 to 0.73 dl / g. Further, the variation rate of the stretching ratio of the obtained stretched film was within 3% in both MD and TD, and the stretched film was uniformly stretched. The heat shrinkage rate of each was within 2%, and the heat resistance was almost the same as that of the stretched film of polyimide alone.

On the other hand, in Comparative Example 1, the current value of the screw motor greatly fluctuated during the production of the unstretched film, and the long-term extrusion stability was poor. The obtained unstretched film had many spots and was ranked C.
The uniform stretchability was good. In Comparative Examples 2 and 4, the extrusion stability of the unstretched film was good, but the variation ratio of the stretching ratio was large, and a stretched film that was uniformly stretched could not be obtained. In Comparative Example 3, the unstretched film had good moldability and uniform stretchability, but the stretched film obtained had a large heat resistance (heat shrinkage rate), and the original heat resistance of the polyimide could not be maintained. It was

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EFFECT OF THE INVENTION According to the method for producing a stretched polyimide film of the present invention, the extrusion stability is good for a long period of time in the production of an unstretched film, the power consumption of the extruder is stable, and the fluctuation of the extrusion rate is suppressed. be able to. In addition, a film having a good surface condition free of lumps and the like can be obtained. Further, the stretched film obtained has little stretching variation, and a stretched film uniformly stretched can be obtained. Furthermore, since the blending amount of the polyether ether ketone is within a specific amount, it is possible to obtain a stretched film that does not impair the heat resistance of the polyimide itself, electrical and electronic industry fields,
It can be preferably used in the field of precision machinery, etc.,
It is an industrially useful stretched film.

Front page continuation (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // B29K 79:00 (72) Inventor Issei Okada 2-1, Tangodori, Minami-ku, Aichi Prefecture Mitsuihigashi Attaku Kagaku Co., Ltd. (72) Inventor Hitoshi Katsuyama 2-1, Tango Dori, Minami-ku, Aichi Prefecture Mitsui Toatsu Kagaku Co., Ltd.

Claims (4)

[Claims] 1. Formula (1) [Chemical Formula 1] A thermoplastic polyimide 50 having a repeating structural unit represented by and having an inherent viscosity of 0.4 to 0.6 dl / g.
~ 97 parts by weight and 1 in melt-in flow dex
The resin composition containing 50 to 3 parts by weight of polyetheretherketone of about 5 g / 10 min is melt-molded to form an unstretched film.
Of a polyimide-based stretched film, characterized in that it is stretched 1.5 to 10 times in one direction or two directions at right angles at a temperature of up to 300 ° C., and is further heat-set at a temperature of 250 ° C. or higher and below the melting point of the film. Production method. 2. The polyether ether ketone has the formula (2):
[Chemical Formula 2] [Chemical Formula 2] The method for producing a stretched polyimide film according to claim 1, which has a repeating structural unit represented by: 3. The melt-forming temperature of the unstretched film is 350.
It is -450 degreeC, The manufacturing method of the polyimide type stretched film of Claim 1 characterized by the above-mentioned. 4. The method for producing a stretched polyimide film according to claim 1, wherein the inherent viscosity of the following solution of the stretched polyimide film at 30 ° C. is in the range of 0.5 to 0.8 dl / g.