JP3475442B2 - Biaxially oriented polyphenylene sulfide film - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxially oriented polyphenylene sulfide film, and more particularly to a biaxially oriented polyphenylene sulfide film excellent in flatness and mechanical properties. [0002] Polyphenylene sulfide (PPS)
In particular, poly-p-phenylene sulfide has excellent mechanical properties, thermal properties, electrical properties, and the like as a biaxially oriented film. , Acoustic diaphragms and release materials. [0003] However, when a biaxially oriented film is manufactured by a method generally used in industry, the flatness and mechanical properties of the obtained film are insufficient due to the effect of hardly meltable crystal nuclei generated during polymerization of PPS. There was a problem such as not. [0004] An object of the present invention is to solve the above-mentioned drawbacks of the conventional PPS film and to provide a homogeneous biaxially oriented PPS film excellent in flatness and mechanical properties. . [0005] In order to achieve the above-mentioned object, the present invention provides at least 90 mol% of repeating units.
The above is composed of p-phenylene sulfide and is an amorphous sheet.
Is obtained by a biaxially oriented polyphenylene sulfide film, wherein the unfused nuclei remaining is not more than 10 / g at. The polyphenylene sulfide referred to in the present invention mainly refers to poly-p-phenylene sulfide and has a p-phenylene sulfide unit of 90 mol% or more. Preferably, 95 mol% or more is p-
It is a phenylene sulfide unit. If such units are less than 10 mol%, for example: Embedded image Embedded image Embedded image Embedded image Embedded image (Where R represents an alkyl, nitro, phenyl or alkoxy group) may be contained as a copolymer component, but the content of these copolymer components is preferably 5 mol% or less in view of film characteristics. preferable. In particular, The polyfunctional copolymer component having three or more functional units is preferably 1 mol% or less from the viewpoint of stretchability. The PPS polymer of the present invention can be obtained by a conventionally known method, that is, by reacting an alkali sulfide with p-dihalobenzene in a polar solvent under high temperature and high pressure. In particular, it is preferable to react sodium sulfide with p-dichlorobenzene in an amide-based high-boiling solvent such as N-methylpyrrolidone (hereinafter referred to as NMP). In this case, in order to adjust the degree of polymerization, it is most preferable to add a so-called polymerization aid such as a caustic alkali or an alkali metal carboxylate and react at 230 ° C to 280 ° C. The pressure and the polymerization time in the polymerization system are appropriately determined depending on the type and amount of the auxiliary agent used, the desired degree of polymerization, and the like. Usually, since the polymer obtained as described above is in the form of a powder, it is preferable that the polymer is melt-extruded using an extruder or the like and cut into a desired size and pelletized. At this time, a PPS composition containing an antioxidant, a heat stabilizer, a lubricant, a nucleating agent, an ultraviolet absorber, a filler for forming a surface, and the like as necessary can be obtained. The temperature of the PPS polymer of the present invention is 315.6 ° C.
Melt flow at 0.5g / 10min or more, 200g
/ 10 minutes or less. More preferably, it is 5 g / 10 min or more and 150 g / 10 min or less, particularly preferably 10 g / 10 min or more and 120 g / 10 min or less. In the PPS film of the present invention, the remaining amount of unmelted nuclei must be 10 or less, preferably 5 or less, more preferably 2 or less.
It is not preferable that the residual amount of unmelted nuclei exceeds 10 pcs / g, because the flatness and strength of the biaxially oriented film are deteriorated. Here, the residual amount of unmelted nuclei refers to an unoriented substantially amorphous sheet observed under a transmission polarizing microscope, and 50 μm per side.
The nuclei having a size of m or more are counted. Here, those having a nucleus size less than 50 μm observed under a polarizing microscope do not adversely affect the characteristics of the biaxially oriented film, but the smaller the number of these nuclei, the better. [0011] The residual amount of unmelted nuclei can be controlled by the extruder cylinder temperature, residence time, and shear rate when pelletizing and / or extruding into an amorphous film. Cylinder temperature is 290 ° C to 350 ° C, residence time is 1 second to 10 minutes,
The shear rate can be selected from a range of 20 sec ^-1 or more.
Here, the residence time refers to the time during which the polymer resides in the extruder cylinder, and the shear rate refers to the average shear rate represented by the following equation. V = πDN / h Here, v is the average shear rate (sec ⁻¹ ), D is the screw diameter (mm), h is the screw groove depth (mm), and N is the screw rotation speed (rps). . For the purpose of increasing the shear rate, a twin-screw extruder can be used, or a strong kneading type extruder such as a dalmage type screw or a screw with a counter-rotating ring can be used. On the other hand, if the extrusion temperature is 350 ° C. or higher, the polymer is deteriorated, and the film forming property is deteriorated and the film characteristics are deteriorated, which is not preferable. [Evaluation of Characteristics] Evaluation of characteristics was performed by the following method. (1) Remaining unmelted nuclei oriented film (crystallized film): Several oriented films are stacked and melt-pressed under the following conditions to form an amorphous sheet. Unoriented film (amorphous film): An amorphous sheet whose thickness is adjusted by controlling the take-off speed. The amorphous sheet was observed with a transmission polarizing microscope, and unmelted nuclei having a size of 50 μm or more on one side were counted, and the counted number was divided by the sheet weight to obtain the remaining unmelted nuclei. Press temperature 300 ° C. Press time 2 minutes Cooling Cold water immersion sheet size 50 mm × 50 mm Sheet thickness 100 μm (2) Melt flow melt indexer (C-5059D-1 manufactured by Toyo Seiki Co., Ltd.)
The discharge amount W (g) for an arbitrary time T (sec) was measured according to ASTM-D1238 under the following conditions using the following formula, and calculated as a value for 10 minutes by the following equation. Pre-drying of the sample: 150 ° C., 20 minutes Measurement temperature: 315.6 ° C. Preheating time: 5 minutes Load: 5 kg Melt flow = (W / T) × 600 (g / 10 minutes) (3) When the flatness interval is 1 m A biaxially stretched film having a width of 500 mm is fixed between two parallel rolls at one end, and tension is uniformly applied to the other end so that the load becomes 0.2 kg / mm ² ,
The area of the uneven portion (slack portion) of the film between rolls was measured. The ratio of the uneven area to the entire area was defined as flatness. The smaller the value, the better the flatness. (4) Strength Measured according to ASTM-D-882-64T. The present invention will be described in more detail with reference to the following examples. Example 1 (1) Preparation of PPS Polymer In a 50 L autoclave (SUS316), 56.25 mol of sodium hydrosulfide (NaSH), 54.8 mol of sodium hydroxide, 16 mol of sodium acetate, and N-methylpyrrolidone ( NMP) 170 mol are charged. next,
The internal temperature was raised to 220 ° C. while stirring under a nitrogen gas stream to perform dehydration. After completion of the dehydration, the system was cooled to 170 ° C., and 55 mol of p-dichlorobenzene (p-DC
B) and 0.055 mol of 1,2,4, -trichlorobenzene (TCB) were added together with 2.5 L of NMP, and the system was pressurized to 2.0 kg / cm ² under a nitrogen stream.
After heating under stirring at 235 ° C. for 1 hour and further at 270 ° C. for 5 hours, the system was cooled to room temperature, the obtained polymer slurry was poured into 200 mol of water, and stirred at 70 ° C. for 30 minutes. Separate the polymer. The polymer was further washed 5 times while stirring with ion-exchanged water (9 times the weight of the polymer) at about 70 ° C., and then stirred for about 1 hour with a 5% by weight aqueous solution of lithium acetate at about 70 ° C. under a nitrogen stream. . Further, after washing three times with ion exchanged water at about 70 ° C., the mixture was separated, and washed at 120 ° C. and 0.8
By drying under an atmosphere of １1 Torr for 20 hours, a white PPS powder was obtained. Next, this PPS powder was subjected to stirring for 1 hour five times with NMP (three times the weight of the PPS polymer) at 70 ° C. in a commercially available nitrogen gas atmosphere. The PPS powder was further washed four times with ion exchanged water at about 70 ° C., separated, and dried as described above to obtain white PP.
S powder was obtained. The melt flow of this PPS powder is 50g
/ 10 minutes. (2) Preparation of PPS Pellets 0.5% by weight of silica powder having an average particle size of 0.5 μm was added and mixed with the above-mentioned PPS powder, and the mixture was supplied to an extruder having a screw diameter of 40 mm to obtain pellets. Extrusion conditions are cylinder temperature of 340 ° C, residence time of 30 seconds, and shear rate of 80 seconds.
^{It was set to -1} . Melt flow of this pellet is 50g / 1
It was 0 minutes. (3) Preparation of PPS Amorphous (Unstretched) Film The above-mentioned pellets were heated at 150 ° C. for 3 m by a rotary vacuum dryer.
The mixture was treated under a reduced pressure of mHg for 3 hours to obtain a crystallized pellet. Next, the crystallized pellets were supplied to a single-screw extruder having a diameter of 40 mm to be extruded, passed through a filter having a filtration accuracy of 10 μm, and had a width of 400 mm and a slit gap of 1.5 mm.
From the stainless steel T-die die with a surface of 50
Cooled and solidified on a metal drum kept at 25 ° C, thickness 25μm
Amorphous film. At this time, the cylinder temperature is 30
0 ° C., residence time 180 seconds, shear rate 15 sec ⁻¹
Met. The melt flow of this film is 50 g / 10
The remaining amount of unmelted nuclei was 1 piece / g. (4) Preparation of PPS Biaxially Stretched Film The above-mentioned amorphous film was wound around a group of rotating rolls having a surface temperature of 95 ° C. and heated.
3.5 times the length of the film (M
D). Next, in a room where hot air of 100 ° C. circulates in a tenter, in the direction perpendicular to the film length (TD).
The film is stretched 5 times, and subsequently heat-treated at a constant length for 10 seconds in a room in which hot air circulates at 260 ° C. to obtain a biaxially oriented PP having a thickness of 2 μm.
S film was used. This film had a very good level of flatness and improved strength. The melt flow of this film was 50 g / 10 minutes, and the remaining amount of unmelted nuclei of an amorphous sheet produced by melt pressing was 1 piece / g.
It was equivalent to an amorphous film before stretching. Table 1 shows the production conditions and the results of film formation. Example 2, Example 3, Example 4, Comparative Example 1, Comparative Example 2 Using the polymer of Example 1, the production conditions of pellets and amorphous films were variously changed, and the thickness of the non-crystalline film was changed. A biaxially oriented PPS film was prepared in the same manner as in Example 1 except that a crystal film was produced. Here, under the conditions of Example 2, Example 3, and Example 4 of the present invention, both the flatness and strength of the obtained film were at good levels. Further, under the conditions of Comparative Examples 1 and 2, which were outside the scope of the present invention, both the flatness and strength of the obtained films were insufficient. Table 1 shows the production conditions and the results of film formation. [Table 1] The present invention improves the flatness and mechanical properties of the present invention, and exhibits excellent properties in applications such as dielectrics of capacitors, electrical insulating materials, electronic components, acoustic diaphragms, and mold release materials. An oriented polyphenylene sulfide film is obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-205425 (JP, A) JP-A-59-115331 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 55/00-55/30 C08J 5/18

Claims (1)

(57) [Claim 1] At least 90 mol% or more of the repeating unit is composed of p-phenylene sulfide, and is an amorphous sheet.
A biaxially oriented polyphenylene sulfide film, wherein the residual amount of unmelted nuclei is 10 / g or less.