JPH044133B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a poly p-phenylene sulfide film having excellent heat aging resistance, mechanical properties, and heat resistant dimensional stability. 2. Description of the Related Art In recent years, technological progress and expansion of applications of electronic and electrical devices have been remarkable, and electronic devices are rapidly becoming more sophisticated, more reliable, smaller, lighter, and less expensive. For this reason, requirements for mechanical and electrical properties, high dimensional stability, etc. for the film materials used are becoming increasingly strict. Currently, polyimide is used as a heat-resistant film, but it has many disadvantages such as high price and poor chemical resistance. Polyethylene terephthalate film has also been used. This film is inexpensive and has excellent mechanical and electrical properties as well as chemical resistance, but its melting point is low at around 260°C, making it difficult to mount electronic components by soldering at around 260°C. There is a problem with heat resistance. The present invention aims to compensate for the drawbacks of these existing films and provide a film that is well-balanced in mechanical properties, electrical properties, and heat resistance, and in particular has extremely excellent dimensional stability under heat. The purpose of the present invention is to provide a film having these characteristics. That is, the present invention

A poly p-phenylene sulfide film containing 90 mol% or more of [Formula], the solution viscosity of the polymer is 0.12 dl/g or more,
Width 10 in the vertical and horizontal directions from this film
mm, length 100 to 150 mm, heat treated at 270°C for 10 minutes in a relaxed state, and then stretched at 23°C at a rate of 200%/min. Tensile strength, reaction at 5% elongation (hereinafter referred to as F -5 value), each value of elongation was compared with each value of tensile strength, F-5 value, and elongation when the film before heat treatment was subjected to a tensile test under the same conditions.
The present invention provides a biaxially oriented poly p-phenylene sulfide film having a retention rate of 60% or more, 80% or more, and 80 to 120%. The polymer used in the present invention has the general formula

It contains 90 mol% or more of the unit represented by the formula, and its polymerization methods include a method of synthesizing by sulfiding an aromatic dihalide and a method of desalting a thiophenol salt. Industrially p
The most preferred method is to perform a polycondensation reaction of p-dihalobenzene such as -dichlorobenzene and sodium sulfide in an amide polar solvent such as N-methylpyrrolidone. Furthermore, the solution viscosity of the polymer component of the film of the present invention is as follows when using α-chlornaphthalene as a solvent at a temperature of 206°C and a concentration of 0.4 g/100 ml.
It is 0.12 dl/g or more, preferably 0.12 to 1.0 dl/g. For example, the following three methods can be used to obtain a polyphenylene sulfide polymer having such a solution viscosity. First, lithium acetate during polymerization,
A method of increasing the molecular weight of the resulting polymer by adding carboxylic acid alkali metal salts, alkaline earth metal salts, etc. such as sodium acetate, calcium acetate, sodium benzoate, lithium benzoate, etc. in an amount of about 10 to 150 mol% of the monomer. There is. Secondly, 2 such as p-diclobenzene is used as a monomer during polymerization.
In addition to functional compounds, there is a method of increasing the solution viscosity by introducing some crosslinked structure into the polymer using, for example, 1,2,4-trichlorobenzene, which is mainly used in combination with the first method. In this case 3
The mixing ratio of the functional monomer to the main monomer is preferably at most 10 mol %, preferably 1 mol % or less. A third method is to expose a polymer having a low solution viscosity to air at a temperature ranging from 200° C. to below the melting point to promote oxidative crosslinking and increase the solution viscosity of the polymer. However, although this method may be preferable when used in combination with the first method, it is not preferable for the present invention to use a polymer whose solution viscosity immediately after polymerization is too low after being oxidatively crosslinked by this method. For example, even if a polymer having a solution viscosity of 0.10 is used as a polymer having a solution viscosity of 0.30 dl/g or more by oxidative crosslinking, the polymer becomes almost impossible to stretch. Furthermore, the second
The third method is preferable when a moderate amount of crosslinked structure is introduced into the polymer as a raw material of the present invention, but if the crosslinked structure is introduced too drastically, the polymer will exhibit rubber elasticity when melted and stretched. In many cases, a film with poor flatness or stretchability may be obtained, making it impossible to obtain a film with the characteristics of the present invention. In order to satisfy the present invention, it is necessary that paraphenylene sulfide units exist in the polymer at 90 mol% or more, and if it is less than 10 mol%, for example, meta bonds

[Formula] Ether bond

[Formula] Biphenyl linkage If

[Formula] Naphthalene bond

[Formula] Sulfone bond

[Formula] Substituted Feni sulfide bond

[Formula] where R is alkyl, nitro, phenyl, alkoxy, sulfone, halogen, carboxylic acid, metal salt of carboxylic acid, etc.), and the aforementioned trifunctional phenyl sulfide bond.

[Formula] etc. may be included. Although the above polymers are used as raw materials for the present invention, additives such as lubricants, antioxidants, ultraviolet absorbers, plasticizers, colorants, etc. may be mixed therein, or the purpose of the present invention may be impaired. There is absolutely no problem in mixing and using polymers and inorganic fillers that do not exist in this range. To produce the film of the present invention, the above raw materials are first formed into a sheet or film using an extruder, press, etc., and then rapidly cooled using liquid nitrogen, water, a roll, etc. to a density of 1.330 g/cm ³ A nearly amorphous unstretched film having the following properties is obtained.
If the crystallization of the unstretched film progresses, the stretchability will decrease and the film will be more likely to break during stretching. Next, stretching is performed. Although the stretching temperature varies somewhat depending on the molecular weight and components of the polymer, it is usually desirable to set it around the glass transition temperature of the polymer. in particular
The temperature is 80-120°C, preferably 90-110°C. Stretching methods that are commonly used such as a roll method, tenter method, and tubular method are convenient. The stretching ratio is preferably 2.5 to 7 times, preferably 2.5 to 6 times, in view of the physical properties and productivity of the resulting film, and either simultaneous biaxial stretching or sequential stretching may be used. In order to increase the density and improve the dimensional stability, heat resistance, mechanical strength, etc. of the biaxially stretched film in this way, heat treatment is particularly necessary to satisfy the mechanical properties that the film of the present invention must have. and crystallize it. The heat treatment conditions are above the melting point (Tm) and below 350℃, preferably Tm
It must be performed under tension at a temperature range of ~340°C for a time of no more than 120 seconds. By this heat treatment, a poly p-phenylene sulfide film having excellent heat resistance and dimensional stability is obtained. Here, the melting point (Tm) is the melting point obtained by DSC (differential scanning calorimeter) of the film immediately after biaxial stretching. At this time, if the heat treatment temperature exceeds 350°C, the film becomes molten and cannot maintain its shape even if the heat treatment time is shortened. If the temperature is in the temperature range from Tm to 350°C, the film can be heat-set within 120 seconds without becoming molten by appropriately adjusting the heat treatment time. In obtaining the film of the present invention, if necessary, the temperature range is 150 to 350°C, preferably 200 to 340°C, before and after the heat treatment process as described above, and within 25% in one or both directions. , preferably 15%
By appropriately treating the film under limited shrinkage or elongation or at a constant length within 10 minutes, thermal shrinkage can be reduced and dimensional stability under heating can be improved. The above heat treatment is performed by bringing a heated gas, liquid or solid into contact with the film before heat treatment. Further, it is also possible to use radiation such as an infrared heater, ultrasonic waves, or high frequency radiation. In the present invention, the "temperature" and "time" of heat treatment refer to the temperature of the heating medium and the contact time to the heating medium when a medium is used,
Also, in the case of using an infrared heater, ultrasonic wave, or high frequency, there are also film temperature and processing time. Heat resistance in a practical sense has various meanings, but one of the most important is dimensional stability during solder immersion. Soldering is the most common method for mounting electronic or electrical components on devices. Materials whose dimensions change during this soldering process cannot be used in electronic and electrical equipment that requires precise dimensional accuracy. In order to improve the dimensional stability during solder immersion, the present inventors conducted detailed studies on the relationship between polymers of various compositions, film manufacturing conditions, and the dimensional stability of the final film. As a result, 270℃, 10
The film of the present invention, in which the strength and elongation retention of the film heat-treated in a relaxed state for a minute or more is a certain value or more, exhibits uniquely excellent dimensional stability when immersed in solder. That is, the film of the present invention has a width of 10 mm in the vertical and horizontal directions and a length of 100 to 150 mm.
The tensile strength, F-5 value, and elongation values when the film was cut out, heat-treated at 270°C for 10 minutes in a relaxed state, and then stretched at 23°C at a rate of 200%/min were as follows. Tensile strength when elongated under the conditions, F
-5 value, 60% or more for each value of elongation,
80% or more, 80~120%, preferably 60~ each
It exhibits excellent dimensional stability during solder immersion by having retention rates of 110%, 80-110%, and 90-120%. The method for producing poly p-phenylene sulfilic film having such mechanical properties is as described above.
In particular, stretching conditions such as extension temperature and stretching ratio as well as heat treatment conditions for crystallization are important. The optimal processing conditions will vary slightly depending on the composition of the polymer, but

The mechanical properties shown in the present invention obtained by using a polymer containing 90 mol% or more of the repeating unit of the formula, or a polymer composition containing this as a main component and a small amount of additives and a blend polymer as a raw material under the production conditions described above. A film having this property exhibits excellent solder heat resistance. The film of the present invention has excellent solder heat resistance, and also has excellent long-term heat resistance and can be used as a heat-resistant film that passes Class F (IEC standard pub86). The film of the present invention is most suitable as an electrically insulating film. For example, base film for flexible printed wiring; insulating material for various rotating machines such as vehicle motors, refrigerator motors, and generators, and various stationary machines; insulating material for covering general cables, high voltage, and ultra-high voltage cables; magnetic Base film for tape; useful as a capacitor film. It is also suitable as an insulating material for dry type and oil-immersed transformers. Furthermore, in addition to electrical insulating materials, it is also used in copying films, tracing films that are exposed to high temperatures during the processing process and require dimensional stability, and food packaging materials used in high-temperature cooking. For other decorations,
It is also useful for building materials, photographic film, acoustic applications such as magnetic disk bases and speaker diaphragms, battery diaphragms, and hot stamping base materials. It can also be used as a composite material by laminating it with other films or by combining it with metals, paper, etc. The present invention will be explained below with reference to Examples. In addition, the tensile test in Examples was conducted under the following conditions. Width 10mm in vertical and horizontal directions, length 100-150mm
It was cut out and elongated at a measurement temperature of 23°C at a rate of 200% extrusion. Example 1 1.8 N-methylpyrrolidone in a 5l autoclave
Kg, 0.5 Kg of sodium sulfide hexahydrate, 0.6 Kg of sodium benzoate, and 1.6 g of sodium hydroxide were charged, and the temperature was gradually raised to 200°C under a nitrogen atmosphere while stirring for about 2 hours, and 105 ml of water was distilled. I let it out. After the reaction system was cooled to 170°C, 0.6 kg of p-diclobenzene and 0.4 kg of N-methylpyrrolidone were added, and the reaction was carried out at 220°C for 2 hours and then at 250°C for 3 hours. The internal pressure at the end of polymerization was 6.7 Kg/cm ² .
After cooling the reaction system, the contents were filtered, and the solid content was washed three times with hot water and twice with acetone.
It was dried at ℃ for 3 hours to obtain a gray, granular polymer. The solution viscosity of this polymer was measured using α-chlornaphthalene at a temperature of 206° C. and a concentration of 0.4 g/100 ml, and found to be 0.29 dl/g. This polymer was press-formed at 310°C and then quenched in water to obtain a transparent unstretched sheet with a thickness of 400 microns. The density of this sheet is 1.321g/cm ²
and was almost amorphous. The glass transition temperature of this sheet was determined using DSC at a heating rate of 10℃/
When measured in minutes, it was 90°C. This amorphous unstretched sheet was simultaneously biaxially stretched 3.5×3.5 times at 94° C. to obtain a film. The Tm of this film was measured by DSC at a heating rate of 10°C/min and found to be 285°C. This film was heat-set at 295° C. for 20 seconds at a constant length, and then subjected to relaxation treatment at 250° C. for 20 seconds at a shrinkage rate of 5%. The final film thickness was 33 microns. Further, the density was 1.366 g/cm ³ . The tensile properties of this film were as follows. Tensile strength (length/width): 23/22 (Kg/mm ² ) F-5 value (length/width): 11/11 (Kg/mm ² ) Elongation (length/width): 62/63 (%) After this film was left in a relaxed state for 10 minutes in an atmosphere at 270°C, its tensile properties were measured in the same manner as before, and the retention rate was determined as follows. Tensile strength retention rate (length/width): 85/83 (%) F-5 value retention rate (length/width): 91/90 (%) Elongation retention rate (length/width): 110/112 (%) Furthermore, the heat shrinkage rate and solder heat resistance of the film were measured before being left in a relaxed state for 10 minutes in an atmosphere of 270°C, and the results were as shown in Table 1.

【table】

[Table] This film has excellent dimensional stability during heating and is useful as a base film for flexible printed wiring boards. Comparative Example 1 The film used in Example 1 before heat setting was
Heat set at a constant temperature for 20 seconds at ℃, then at the same temperature for 20 seconds.
Relaxation treatment was performed at a contraction rate of 5% per second. The tensile properties of this film were as follows. Tensile strength (length/width): 20/22 (Kg/mm ² ) F-5 value (length/width): 10/10 (Kg/mm ² ) Elongation (length/width): 61/58 (%) After this film was left in a relaxed state for 10 minutes in an atmosphere at 270°C, its tensile properties were measured in the same manner as before, and the retention rate was determined as follows. Tensile strength retention rate (length/width): 47/51 (%) F-5 value retention rate (length/width): 73/75 (%) Elongation retention rate (length/width): 131/125 (%) Further, the heat shrinkage rate and solder heat resistance of the film were measured before being left in a relaxed state for 10 minutes in an atmosphere at 270°C, and the results were as shown in Table 2.

[Table] Example 2 585 g of p-dichlorobenzene as a monomer,
Polymerization was carried out under the same conditions as in Example 1 except that 2.1 g of 1,2,4-trichlorobenzene was used to obtain a grayish-white, granular polymer. The solution viscosity of this polymer was measured under the same conditions as in Example 1.
It was 0.42 dl/g. This polymer was press-formed at 310°C and then quenched in water to obtain a transparent unstretched sheet with a thickness of 400 microns. When we measured the density of this sheet
It was 1.322 g/cm ² and was almost amorphous.
The glass transition temperature of this sheet was measured in the same manner as in Example 1 and was found to be 91°C. This amorphous unstretched sheet was simultaneously biaxially stretched 3.5×3.5 times at 95° C. to obtain a film. The Tm of this film was measured in the same manner as in Example 1 and was found to be 279°C. This film was heat-set at 305° C. for 20 seconds at a constant length, and then subjected to relaxation treatment at 260° C. for 15 seconds at a shrinkage rate of 5%. The initial film thickness was approximately 33 microns and the density was 1.364 g/cm ³ . The results of the tensile properties of this film are shown below. Tensile strength (length/width): 19/20 (Kg/mm ² ) F-5 value (length/width): 10/10 (Kg/mm ² ) Elongation (length/width): 58/57 (%) After this film was left in a relaxed state for 10 minutes in an atmosphere at 270°C, its tensile properties were measured in the same manner and the retention rate was determined as follows. Tensile strength retention rate (length/width): 86/85 (%) F-5 value retention rate (length/width): 95/93 (%) Elongation retention rate (length/width): 109/111 (%) In addition, when we measured the heat shrinkage rate and solder heat resistance of the film before leaving it in a relaxed state for 10 minutes in an atmosphere at 270℃, the heat shrinkage rate at 250℃ was 0.6%, and the heat shrinkage rate at 260℃ for 30 seconds was measured. The shrinkage rate in one direction due to solder immersion was 0.7%, indicating that the film of the present invention has excellent dimensional stability during heating. Comparative Example 2 The film used in Example 2 before heat setting was
Heat set under constant length for 20 seconds at 250 °C, then 15 seconds at 250 °C.
Relaxation treatment was performed at a contraction rate of 5% per second. The density of this film was 1.348 g/cm ³ . The results of the tensile properties of this film are as follows. Tensile strength (length/width): 17/18 (Kg/mm ² ) F-5 value (length/width): 10/10 (Kg/mm ² ) Elongation (length/width): 51/49 (%) After this film was left in a relaxed state for 10 minutes in an atmosphere at 270°C, its tensile properties were measured in the same manner, and the retention rate was determined as follows. Tensile strength retention rate (length/width): 53/51 (%) F-5 value retention rate (length/width): 75/74 (%) Elongation retention rate (length/width): 131/135 (%) In addition, when we measured the heat shrinkage rate and solder heat resistance of the film before leaving it in a relaxed state for 10 minutes in an atmosphere at 270°C, the heat shrinkage rate at 250°C was 9.3%, and at 260°C for 30 seconds. The shrinkage rate in one direction due to solder immersion was 11%, and wrinkles appeared in the film. This film has poor dimensional stability when heated;
It was unsuitable for use as a flexible printed wiring board that undergoes soldering. Comparative Example 3 The film used in Example 2 before heat setting was
Heat set under constant length for 20 seconds at 250 °C, then 15 seconds at 250 °C.
Relaxation treatment was performed at a contraction rate of 5% per second. The density of this film was 1.353 g/cm ³ . The results of the tensile properties of this film are as follows. Tensile strength (length/width): 17/18 (Kg/cm ² ) F-5 value (length/width): 10/10 (Kg/cm ² ) Elongation (length/width): 54/52 (%) After this film was left in a relaxed state for 10 minutes in an atmosphere at 270°C, its tensile properties were measured in the same manner, and the retention rate was determined as follows. Tensile strength retention rate (length/width): 57/55 (%) F-5 value retention rate (length/width): 76/75 (%) Elongation retention rate (length/width): 127/131 (%) In addition, when we measured the heat shrinkage rate and solder heat resistance of the film before leaving it in a relaxed state for 10 minutes in an atmosphere at 270℃, the heat shrinkage rate at 250℃ was 3.4%, and the heat shrinkage rate at 260℃ for 30 seconds was measured. It was found that the shrinkage rate in one direction due to solder immersion was 4.1%, and there was a problem with dimensional stability.

Claims (1)

[Scope of Claims] 1. A poly p-phenylene sulfide film containing 90 mol% or more of the repeating unit [Formula], wherein the solution viscosity of the polymer is 0.12 dl/g.
above, and cut this film into a piece with a width of 10 mm and a length of 100 to 150 mm in the vertical and horizontal directions,
After heat treatment at 270℃ for 10 minutes in a relaxed state, 23℃,
The tensile strength when stretched at a speed of 200%/min, the stress at 5% elongation, and the elongation are the tensile strength and elongation when the film before heat treatment is stretched under the above conditions.
1. A biaxially oriented poly p-phenylene sulfide film having a retention rate of 60% or more, 80% or more, and 80 to 120%, respectively, when compared with the respective values of stress and elongation.