JPH048453B2 - - 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 problem] As a result of intensive research, the inventors of the present application subtracted the amount of acetone-soluble oligomer from the amount of xylene-soluble oligomer in a biaxially oriented poly-p-phenylene sulfide film. The inventors have discovered that when the difference is within a specific range, the film has excellent heat resistance, mechanical properties, electrical properties, Freon resistance, etc., and has completed this invention. That is, in this invention, the difference between the amount of xylene soluble oligomer and the amount of acetone soluble oligomer is
Biaxially oriented poly-p from 0.1% to 2.0% by weight
-Providing a phenylene sulfide 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 difference obtained by subtracting the amount of acetone-soluble oligomer from the amount of xylene-soluble oligomer (hereinafter sometimes referred to as Xy-Ac) is 0.1% by weight. to 2.0% by weight, preferably from 0.5% to 1.0% by weight. If Xy-Ac exceeds 2.0% by weight, all 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, resulting in equipment stains, etc. Due to this, film tearing occurs frequently. Moreover, if it is less than 0.1% by weight, physical properties such as bending resistance, impact resistance, scratch resistance, and elongation of the film 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 having an affinity for poly-p-phenylene sulfide, such as diphenyl ether, to give Xy-
Ac can be controlled. Xy− of this powder
Ac is usually about 2 to 3% by weight. 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 constant length heat treatment referred to 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.
A p-phenylene sulfide film can be obtained, but among the above steps, the things that affect Xy-Ac are the polymerization temperature and time, the type and amount of auxiliary agents used, and washing with an organic solvent after polymerization. By appropriately controlling these factors, the Xy-Ac of 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, heat shrinkage rate, melt viscosity, element winding BDV, Freon resistance, amount of xylene soluble oligomer, amount of acetone soluble 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. Amount of Xylene Soluble Oligomer A biaxially oriented film was repeatedly extracted using xylene as a solvent using a Soxhlet extractor for 24 hours, and then the xylene soluble content was dried and solidified. Amount of acetone-soluble oligomers: Using a Soxhlet extractor, extract the biaxially oriented film with acetone as a solvent for 3 hours or more until the extraction amount becomes constant, and then dry and solidify the acetone-soluble content. Ta. 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-diclobenzene (hereinafter referred to as p
-DCB) and 0.055 mol of 1,2,4-trichlorobenzene (hereinafter abbreviated as TCB) to 2.5 mol of
Added with NMP and heated the system under nitrogen stream at 2.0Kg/cm ²
It was sealed under pressure. 1 hour at 230℃, then 270℃
After heating under stirring for 3 hours at °C, the system was cooled,
The obtained polymer was washed with diphenyl ether,
After extraction, low molecular weight components were removed and collected through a 200-mesh wire mesh, the obtained polymer was washed with 8 times the amount of water and filtered repeatedly, and then dried to obtain 4.9 kg of polymer. Obtained. The melt viscosity of the polymer thus obtained is
It exhibited 4800 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, then 3.5 times horizontally stretched 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. xylene using a Soxhlet extractor
Extraction at 185℃ for 24 hours yielded 0.6% by weight of oligomer extract, and extraction with acetone for 3 hours yielded 0.05% by weight of oligomers.
Ac was 0.55% by weight. This film has a strength of 21.5Kg/mm ² and an elongation of 59%.
The Young's modulus is 405Kg/mm ² , and the physical properties after being left in the air at 220℃ for 700 hours are strength 17.0Kg/mm ² and elongation.
50%, which showed extremely excellent heat resistance. Meanwhile, this film was cut into strips and autoclaved in Freon/Suniso oil at 155℃ and 35Kg/cm ² .
The amount of oligomer after 500 hours of treatment was as low as 0.07% by weight, and it was found that the product had excellent Freon resistance. The properties of the obtained polymer are summarized in Table 1, and the evaluation results of the film are summarized in Table 2.

【table】

[Table] Comparative Example 1 Polymerization was carried out in the same manner as in Example 1.
After the polymerization was completed, the contents were introduced into water to obtain granular polymer. Washing and drying were carried out in the same manner as in Example 1 to obtain 5.1 kg of white granular polymer. This polymer was tested at 300°C under a shear rate of 200/s
It showed 3800 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. Extraction of the film with xylene using a Soxhlet extracted 2.6% by weight of oligomers, acetone extracted 0.3% by weight of oligomers, and 2.3% by weight of Xy-Ac. This film has a strength of 17.5Kg/mm ² and an elongation of 45.5%.
The Young's modulus is 385Kg/mm ² , and the physical properties after being left in the air at 220℃ for 700 hours are strength 10.5Kg/mm ² and elongation.
It was shown that it was thermally unstable at 20.5%. 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, time) were varied, and the thickness of the unoriented film sheet was varied as shown in Table 2. Examples 2 and 3 and Comparative Examples 2 and 3 were carried out in the same manner as in Example 1 except for the following. 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, which has a small amount of extraction by a specific extractant, has better mechanical properties than the conventional film.
It can be seen that heat resistance is improved, and freon resistance and electrical properties are also improved. 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 xylene extraction and acetone extraction separately, and Xy-Ac was
A 0.05% by weight film was prepared and its physical properties were compared with the film of Example 1. The results are shown in Table 3.

【table】

Claims (1)

[Claims] 1. A biaxially oriented poly-p-phenylene sulfide film in which the difference obtained by subtracting the amount of acetone-soluble oligomer from the amount of xylene-soluble oligomer is 0.1% by weight to 2.0% by weight.