JPH048457B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention relates to a biaxially oriented poly-p-phenylene sulfide film. [Prior art and its disadvantages] Biaxially oriented poly-p-phenylene sulfide film has extremely excellent performance in terms of heat resistance, chemical resistance, electrical insulation, dielectric properties, mechanical properties, etc. It has been proposed to be used in dielectric materials for capacitors, base films for magnetic recording media, electrical insulation materials, flexible printed circuit boards, etc. Poly-p-phenylene sulfide is produced, for example, by a known method described in Japanese Patent Publication No. 45-3368, but since the polymerization of poly-p-phenylene sulfide is carried out at high temperature and high pressure. Because the obtained polymer has a wide molecular weight distribution, it contains a relatively large amount of oligomer components that cause foaming during melt molding, generation of tar, thermal deterioration, and a decrease in product stability and mechanical properties. . To eliminate these drawbacks caused by the oligomer component, the amount of acetone soluble oligomer was reduced to 2.0
A poly-p-phenylene sulfide polymer suppressed to less than 1% by weight has been proposed (Japanese Patent Application Laid-Open No. 1987-1999).
No. 205425). However, the acetone soluble oligomer 2.0
Even with biaxially oriented poly-p-phenylene sulfide film produced from polymers that are kept below % by weight, (1) the heat resistance deteriorates significantly due to oligomers, (2) the strength and elongation, Young's modulus are low, and the heat shrinkage rate is low. (3) poor electrical properties; and (4) poor Freon resistance. In addition, in the manufacturing process, (1) the viscosity changes significantly during the melting process, making it difficult to make the extrusion rate uniform; (2) the amount of gas generated during melt extrusion is large, resulting in contamination of the die lip and shortened SI electrode wire life. lowering, casting drums, longitudinal stretching rolls,
It has drawbacks such as frequent tearing of the film due to dirt on tenter rails and clips. Because of these drawbacks, poly-p-phenylene sulfide films have not been able to completely satisfy the required properties of various uses thereof, and the range of use of such films has been greatly limited. [Problems to be Solved by the Invention] An object of the present invention is to overcome the above-mentioned drawbacks and to provide a biaxially oriented poly-p-phenylene sulfide having excellent heat resistance, mechanical properties, electrical properties, freon resistance, etc. The goal is to provide film. [Means for Solving the Problems] As a result of intensive research, the present inventors have determined that the amount of oligomers with a molecular weight of 300 to 2000 contained in a biaxially oriented poly-p-phenylene sulfide film is within a specific range. , the film's heat resistance, mechanical properties,
This invention was completed after discovering that it has excellent electrical properties, freon resistance, etc. That is, the present invention provides a biaxially oriented poly-p-phenylene sulfide in which the content of poly-p-phenylene sulfide oligomers having a molecular weight in the range of 300 to 2000 is 0.1% to 2.0% by weight of the total weight. Provide film. [Effects of the Invention] The biaxially oriented poly-p-phenylene sulfide film of the present invention has (1) low heat resistance deterioration, (2) good mechanical properties, and (3) significantly good electrical properties, especially BDV. , and (4) high Freon resistance. In addition, in the manufacturing process, (1) changes in viscosity during the melting process can be reduced and the extrusion amount can be made uniform; (2) the amount of gas generated during melt extrusion is extremely small, making it possible to reduce the , there is almost no dirt on the casting drum, and problems such as film tearing are significantly reduced. [Specific Description of the Invention] In this specification, poly-p-phenylene sulfide means that 70 mol% or more (preferably 85 mol% or more) of the repeating units have the general formula Refers to a polymer consisting of the structural units shown below. If the content of such components is less than 70 mol%, the crystallinity, thermal transition temperature, etc. of the polymer will be low, and the heat resistance, dimensional stability, mechanical properties, etc. of the resulting film and laminate thereof will be impaired. A unit containing a copolymerizable sulfide bond may be included as long as it is less than 30 mol% (preferably less than 15 mol%) of the repeating units. For example, such a unit is

【formula】

【formula】

【formula】

【formula】

[Formula] (R is -COOH or -SO ₃ H, X is -
CH ₂ −, −CH ₂ CH ₂ −, or

[Formula]) can be mentioned. Further, in this specification, a poly-p-phenylene sulfide film refers to a film containing 90% by weight or more of the above-mentioned poly-p-phenylene sulfide. If the content of poly-p-phenylene sulfide is less than 90% by weight, the heat resistance, dimensional stability, mechanical properties, etc. of the film and its laminate will be impaired. The remaining less than 10% by weight of the film is poly-
Polymers other than p-phenylene sulfide and/or
Alternatively, it may be an additive such as a filler, a lubricant, a coloring agent, an ultraviolet absorber, an antistatic agent, or an antioxidant. In the biaxially oriented poly-p-phenylene sulfide film of the present invention, the content of oligomers having a molecular weight in the range of 300 to 2000 is 0.1% to 2.0% by weight, preferably 0.5% by weight based on the entire film. % to 1.0% by weight. molecular weight 300
If the content of the 2000 oligomer exceeds 2.0% by weight, all the physical properties of the film, including heat resistance, mechanical properties, electrical properties, and Freon resistance, will deteriorate, and the amount of gas generated during melt extrusion will be extremely large, causing problems with the equipment. Film tears often occur due to dirt, etc. Also,
If it is less than 0.1% by weight, the physical properties of the film such as bending resistance, impact resistance, scratch resistance, and elongation will deteriorate. The biaxially oriented poly-p-phenylene sulfide film of the present invention can be produced as follows. First, as a method for polymerizing poly-p-phenylene sulfide, a method is used in which alkali sulfide and p-dihalobenzene are reacted in a polar solvent at high temperature and high pressure. In particular, it is preferable to react sodium sulfide and p-dihalobenzene in an amide-based high-boiling polar solvent such as N-methylpyrrolidone. In this case, to adjust the degree of polymerization, alkali hydroxide,
Most preferably, a so-called polymerization aid such as an alkali carboxylic acid salt is added and the reaction is carried out at a temperature of 230°C to 280°C. The pressure in the polymerization system and the polymerization time are:
It is appropriately determined depending on the type and amount of the auxiliary agent used, the desired degree of polymerization, etc. When the polymer after polymerization is washed with water and dried, poly-p-phenylene sulfide powder is obtained. If necessary, the recovered polymer is washed at high temperature with an organic solvent that has an affinity for poly-p-phenylene sulfide, such as diphenyl ether, to control the low molecular weight components that are the focus of the present invention. can do. The resin powder thus obtained is supplied to a well-known melt extrusion device such as an extruder and melted. Next, 95% of the molten resin is filtered through a high-precision filter with a cut hole diameter of 3 to 20 μm, preferably 3 to 15 μm, and then continuously extruded from a so-called T-die, cast onto a cooled metal drum, and rapidly cooled. It is solidified to form an unoriented sheet.
The surface of the metal drum is preferably finished to a mirror surface with a roughness of 0.4S or less. Next, the sheet thus obtained is biaxially stretched. As the stretching method, well-known methods such as sequential biaxial stretching method and simultaneous biaxial stretching method can be used. It is preferable to use the so-called longitudinal and transverse sequential biaxial stretching method. The stretching temperature is preferably in the range of 95 to 110°C in both length and width.
On the other hand, the stretching ratio varies depending on resin viscosity, stretching temperature, etc., and cannot be definitively stated, but in the longitudinal direction it is approximately 3.2~
It is preferable to stretch the film by 4.5 times, and preferably by 3.0 to 3.8 times in the width direction. Next, the stretched film thus obtained is subjected to fixed length heat treatment. What is the constant length heat treatment mentioned here?
This means that the change in width and length during heat treatment is 10% or less. The heat treatment conditions are from 250℃ to 290℃ for 1 second to 50 seconds, but from 260℃ to 285℃.
Preferably, the reaction is carried out for 3 to 20 seconds at ℃. After constant length heat treatment, relaxation is performed at a temperature of 240°C to 290°C. The relaxation rate starts from 4 in the width direction.
10%, and about 0 to 6% in the longitudinal direction. By the above steps, the biaxially oriented polyurethane of the present invention can be obtained.
p-phenylene sulfide film can be obtained, but in the above process, the molecular weight is from 300 to 2000.
Things that affect the content of oligomers include polymerization temperature and time, type and amount of auxiliaries used, presence or absence of washing with an organic solvent after polymerization, time, temperature, etc.
By appropriately controlling these factors, the content of oligomers having a molecular weight of 300 to 2,000 in the resulting film can be controlled within the scope of the present invention. [Examples of the Invention] Next, Examples and Comparative Examples of the present invention will be shown to specifically explain the effects of the present invention. In each example, strength and elongation, thermal shrinkage rate, melt viscosity, element winding BDV, freon resistance, average molecular weight and molecular weight distribution of oligomer, impact strength, bending resistance, and tear propagation resistance were measured as follows. . Strength and elongation Tested with Tensilon type tensile tester, width 10mm, sample length
Determine the breaking elongation and breaking strength of a 50 mm sample, n=
It was calculated as the average value of 5. Thermal Shrinkage Rate A film with a sample length of 200 mm and a width of 10 mm was heated in a hot air oven at a constant temperature for 10 minutes under no load, and the shrinkage rate was calculated from the length before and after heating. Melt viscosity Measured using a Koka type flow tester (measurement temperature: 300°C, shear rate: 200/sec). Element-wound BDV The slit was wrapped in foil and BDV was measured with or without pressing under the following conditions. Product number: 2.5μm, capacity: 0.1mF, press conditions:
180℃, 15Kg/cm ² , number of samples: 100, pressure increase rate:
100V/sec Freon Resistance Put a tanzaku-like film in 200ml of Freon R-22 and 300ml of Suniso oil, and heat at 155°C at 35°C.
It was treated for 500 hours under the condition of Kg/cm ²³ and the amount of freon extracted was measured. Average molecular weight and molecular weight distribution of oligomers Measured by gel permeation chromatography.
The equipment and measurement conditions used were as follows. Equipment: Gel permeation chromatograph GPC-244
(Manufactured by WATERS) Data processing: Gel permeation chromatography data processing system manufactured by Toray Research Center Co., Ltd. Column: TSK-Gel-G2500 x L (2),
G3000 x L(1), G2000 x L(1)
(Manufactured by Toyo Soda Kogyo Co., Ltd.) Solvent: Chloroform Flow rate: 1 ml/min Temperature: 23°C Sample: Concentration - All samples dissolved in 10 ml Solubility - Complete dissolution filtration - 0.5 μm Cephadex DT ED
-13CR (manufactured by Pharmacia) Injection volume: 0.2ml Detector: Differential refractive index detector R-401 (WATERS)
) Molecular weight calibration: Polystyrene impact strength Measured using a falling ball impact tester. Bending resistance Measured using an MIT bending tester. Tear propagation resistance Measured using a Charpey tear tester. Example 1 Sodium bisulfide in a 50 capacity autoclave
56.25 mol, sodium hydroxide 54.8 mol, sodium acetate 16 mol and N-methylpyrrolidone (hereinafter referred to as
170 mol of NMP (abbreviated as NMP) was charged, and the internal temperature was raised to 220°C while stirring under a nitrogen gas stream to perform dehydration. After dehydration, the system was cooled to 170°C, and 55 mol of p-dichlorobenzene (hereinafter referred to as
p-DCB) and 0.055 mol of 1,2,4-trichlorobenzene (hereinafter abbreviated as TCB).
of NMP, and the system was heated to 2.0 kg/kg under nitrogen flow.
It was sealed under pressure to a ^depth of cm2. 1 hour at 230℃, then
After heating at 270°C for 3 hours with stirring, the system was cooled, and the resulting polymer was washed and extracted with diphenyl ether to remove low molecular weight components, and collected through a 200 mesh wire gauze. The obtained polymer was repeatedly washed with 8 times the amount of water and filtered, and then dried to obtain the polymer of this example. The properties of this polymer are summarized in Table 1.

[Table] The melt viscosity of the polymer obtained in this way is
It exhibited 4700 poise at 300°C and a shear rate of 200/sec. This polymer was extruded into pellets at 320°C using a twin-screw extruder with a diameter of 30 mm.
No gas was generated during pelletizing. The pellets were dried at 180° C. for 3 hours under a reduced pressure of 5 mmHg. Next, it is fed to a single-screw extruder with a diameter of 40 mm, passed through a metal fiber filter with a 10 μm cut, and cast from a 250 mm wide T-die onto a mirror drum with a surface temperature of 30°C to form an unoriented sheet with a thickness of about 50 μm. Got a sheet. During extrusion, there was no smoke emitted from the T-die and no oligomer adhesion. This unoriented sheet was stretched 3.8 times using a roll-type longitudinal stretching device, further stretched 3.5 times horizontally using a tenter, and then heat-treated at 270°C for 10 seconds in the same tenter, resulting in 8% horizontal stretching. By performing relaxation, a biaxially oriented film with a thickness of about 4 μm was obtained.
The properties of this film are summarized in Table 2.

[Table] The content of oligomers with a molecular weight of 300 to 2000 in this film was 0.6% by weight, and as shown in Table 2, the film had excellent strength, elongation, Young's modulus, and physical properties after being left in air at 220°C. It showed heat resistance. In addition, this film was cut into strips and autoclaved in Freon/Suniso oil at 155℃.
The amount of oligomer after 35Kg/cm ² and 500 hours of treatment is
It showed a small value of 0.07% by weight, and it was found that the freon resistance was also very excellent. Comparative Example 1 Polymerization was carried out in the same manner as in Example 1.
After the polymerization was completed, it was cooled, and a granular polymer was obtained without washing or extracting the obtained polymer with an organic solvent. Washing and drying were carried out in the same manner as in Example 1 to obtain 5.0 kg of white granular polymer. This polymer was tested at 300°C under a shear rate of 200/s
It showed 3600 poise. A biaxially oriented film with a thickness of 4 μm was obtained by pelletizing, casting, and stretching using the same method as in Example 1. Compared to Example 1, gas generation was intense during pelletizing, and smoke from the T-die during extrusion and die streaks due to oligomer adhesion were observed. The amount of oligomers with a molecular weight of 300 to 2000 in this film was 2.6% by weight, and as shown in Table 2, the strength and
The elongation, Young's modulus, and physical properties after being left in air at 220°C for 700 hours were poor, and it was also shown to be thermally unstable. Furthermore, the amount of oligomer after treatment in Freon/Suniso oil is 0.32%, which is poor in Freon resistance. The properties of the obtained polymer are shown in Table 1.
The evaluation results of the film are summarized in Table 2. Examples 2 and 3, Comparative Examples 2 and 3 The presence or absence of washing with diphenyl ether after polymerization and its degree (temperature and time) were varied, and
Examples 2 and 3 Comparative Examples 2 and 3 were carried out in the same manner as in Example 1 except that the thickness of the unoriented film sheet was changed as shown in Table 2. The properties of the obtained polymer are summarized in Table 1, and the evaluation results of the film are summarized in Table 2. Table 2 shows that the film of the present invention, in which the content of oligomers with a molecular weight of 300 to 2000 is 0.1% by weight or more and 2% by weight or less, has improved mechanical properties and heat resistance, as well as Freon resistance and electrical properties, compared to conventional films. I understand that. Comparative Example 4 A biaxially oriented film with a thickness of 25 μm was obtained in the same manner as in Example 1. This film was subjected to solvent extraction to produce a film containing 0.05% by weight of oligomers with a molecular weight of 300 to 2000.
The physical properties were compared with those of other films. The results are shown in Table 3.

【table】

【table】

Claims (1)

[Claims] 1 The content of poly-p-phenylene sulfide oligomer with a molecular weight in the range of 300 to 2000 is
Biaxially oriented poly-p from 0.1% to 2.0% by weight
- Phenylene sulfide film.