JP3198666B2 - Biaxially stretched film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biaxially stretched film. More specifically, the present invention relates to a biaxially stretched film suitable for a capacitor or the like.

[0002]

2. Description of the Related Art Inert particles are added to a film to form fine irregularities on the film surface to give the film an appropriate slipperiness and to improve the handling properties (slipperiness, running stability, etc.) of the film. (Japanese Unexamined Patent Application Publication No. 55-3
No. 4968).

[0003] Further, with the recent miniaturization of electronic devices and the like, the demand for ultra-thin films is increasing in the field of films. However, in the application of film capacitors, which require a very thin film, the processing process is complicated, so that excellent slipperiness is required, and the added inert particles fall off, the film is damaged, It is necessary to minimize adverse effects such as an increase in insulation defects due to voids generated around the particles, especially an increase in pinholes, and a decrease in withstand voltage. It was difficult to realize.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional disadvantages and to add carefully selected inert particles to a film to improve practical properties such as handleability and electrical properties of the film. It is another object of the present invention to provide a biaxially stretched film which can be sufficiently compatible even when it is extremely thin, and in particular, has few pinholes.

[0005]

SUMMARY OF THE INVENTION The present invention provides the following objects. A biaxially stretched film made of a crystalline thermoplastic resin composition containing polyphenylene sulfide as a main component , wherein the resin composition has two types of non-crystalline films having different particle sizes so as to satisfy the following formulas (1) to (3). a biaxially stretched film, characterized in that the active particles are contained.

0.15 ≦ D ₁ /t≦0.60 (1) 0.70 ≦ D ₂ /t≦1.1 (2) 0.30 ≦ c ₁ · D ₁ + c ₂ · D ₂ ≦ 0. 50 (3) D ₁ : Average particle size of first inert particles (μm) D ₂ : Average particle size of second inert particles (μm) t: Average thickness of biaxially stretched film (μm) c ₁ : Weight content of first inert particles (%) c ₂ : weight content of second inert particles (%) The biaxially stretched film according to claim 1, wherein the relative standard deviation of the area circle equivalent diameter represented by the following formula (4) of at least one of the inert particles is 1.0 or less.

Σ / d = ｛Σ (di−d) ² / N｝ ^1/2 / d (4) (where di is the circle equivalent diameter of each of the inert particles and d is the one of the inert particles) 2. The average particle size of the inert particles, N is the number.) 2. The biaxially stretched film according to claim 1, wherein the inert particles are calcium carbonate, silica or crosslinked polystyrene particles.

[0008]

[0009] 4 . The average thickness of the biaxially stretched film is 0.2
2. The biaxially stretched film according to claim 1, wherein the thickness is from 2 μm to 2 μm.

In the present invention, the crystalline thermoplastic resin composition is a resin composition containing at least 70% by weight, preferably at least 85% by weight of a crystalline thermoplastic resin. 30% by weight
If it is less than 15% by weight, preferably various additives such as other polymers, inorganic or organic lubricants, coloring agents, ultraviolet absorbers, antioxidants, heat stabilizers, and crystal nucleating agents are included. You can be there. Here, the crystallinity is generally referred to as the crystallinity of a polymer in which an endothermic peak is observed at a temperature lower than the melting point when the temperature is lowered from a molten state by differential thermal analysis.

[0011] The crystalline thermoplastic resin in the present invention is polyphenylene sulfide .

[0012] The port re polyphenylene sulfide in the present invention is a polymer containing phenylene sulfide units as a main recurring unit. Here, “the main repeating unit” means a polymer containing the repeating unit in an amount of 70 mol% or more, preferably 85 mol% or more, more preferably 95 mol% or more, and other copolymerizable components, for example, ,

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image Or a small amount

Embedded image It is no problem that the trifunctional component is copolymerized.

[0013]

The effect of the polyphenylene sulfide is particularly large when the polyphenylene sulfide film has a xylene extraction amount of 1.5% by weight or less. Here, the xylene extraction amount refers to the ratio of the weight of the extract to the weight of the film before extraction when the film is extracted with xylene for 36 hours by a Soxhlet extractor immersed in an oil bath heated to 200 ° C. .

The biaxially stretched film of the present invention is a film obtained by melt-extruding, biaxially stretching, and heat setting a resin composition containing the above resin to which inert particles are added as a main component. When the thickness of the film is 0.2 μm or more and less than 2.0 μm, the effect of the present invention is large.

The inert particles used in the film of the present invention must be selected and added so as to satisfy the following requirements.

0.15 ≦ D ₁ /t≦0.60 (1) 0.70 ≦ D ₂ /t≦1.1 (2) 0.30 ≦ c ₁ · D ₁ + c ₂ · D ₂ ≦ 0. 50 (3) D ₁ : Average particle size of first inert particles (μm) D ₂ : Average particle size of second inert particles (μm) t: Average thickness of biaxially stretched film (μm) c ₁ : Weight content of first inert particles (%) c ₂ : weight content of second inert particles (%) Hereinafter, these formulas will be described in order.

Here, the second inert particles consist of particles having a larger average particle size than the first inert particles.

Formula (1) shows the relationship between the average particle size (μm) of the first inert particles and the thickness (μm) of the biaxially stretched film made of the resin composition. More preferably, it is in the range of 0.20 ≦ D ₁ /t≦0.60, and still more preferably in the range of 0.20 ≦ D ₁ /t≦0.50. By adding inert particles having a specific particle size range with respect to the film thickness in this way, it is possible to contribute to improvement in slipperiness without generating pinholes. On the other hand, D ₁ /
Inert particles having a t of less than 0.15 are not preferred because they cannot contribute to the improvement of the slipperiness.

Formula (2) shows the relationship between the average particle size (μm) of the second inert particles and the thickness (μm) of the biaxially stretched film made of the resin composition. More preferably, the range is 0.75 ≦ D ₂ /t≦1.0, and even more preferably, the range is 0.80 ≦ D ₂ /t≦0.9. As described above, by adding the second inert particles which are relatively large with respect to the film thickness, it is possible to achieve both the slipperiness and the pinhole. If D ₂ / t exceeds 1.1, many pinholes are generated, which is not preferable.

Equation (3) shows the amount of inert particles added in relation to equations (1) and (2). More preferably, 0.30 ≦ c ₁ · D ₁ + c ₂ · D
The range is ₂ ≦ 0.50. Satisfying this relational expression,
That is, when the film thickness is large with respect to the average particle size of the inert particles, the addition amount is small, and when the film thickness is small with respect to the average particle size of the inert particles, the addition amount is increased to form the film surface. The density and height of the projections can be controlled, and all the required properties such as the handling properties of an ultra-thin film, the handling properties with a support film, and the electrical properties of the ultra-thin film can be satisfied.

Equation (4) shows the relative standard deviation of the equivalent circle diameter of one inert particle.

Σ / d = {(di−d) ² / N} ^1/2 / d (4) (where di is the circle equivalent diameter of each of the inert particles and d is the one of the inert particles) In the present invention, the relative standard deviation is preferably 1.0 or less, and more preferably 0.8 or less. By using such spherical inert particles, the projections formed on the film become uniform, and the film is damaged due to friction between the films or between the film and metal, and an increase in insulation defects due to falling off of the particles. Can be suppressed.

The inert particles used in the present invention that satisfy the above relational expression include inorganic particles such as silica, alumina, calcium carbonate, kaolin, calcium phosphate, barium sulfate, titanium oxide, talc and zinc oxide, and crosslinked polystyrene. Organic particles that do not melt up to 300 ° C., such as system particles, may be mentioned. Preferably, silica particles derived from colloidal silica, spherical calcium carbonate, and crosslinked polystyrene particles are used. These particles have good affinity with the polymer and are unlikely to form voids around the particles during stretching, so that a film having a high withstand voltage can be obtained as a film for a capacitor. This is a very important point in ultra-thin films. As a method of adding these inert particles, either a method of adding them during polymerization of the resin or a method of melt-kneading after polymerization may be used. Further, it may contain inert particles such as a catalyst residue precipitated during polymerization. Fine inert particles having an average particle size of 0.02 μm or less can also be added. In this case, the amount of the fine inert particles to be added is 1.0% by weight or less. Is preferred.

The biaxially stretched film of the present invention may be laminated with a peelable support film. The thickness of the support film is twice the thickness of the biaxially stretched film of the present invention composed of the resin composition (A) to be laminated (hereinafter, referred to as film A when distinguished from the support film). It is preferably at least 10 times or less. The support film is also a crystalline thermoplastic resin composition, biaxially stretched,
It is preferable to be heat-fixed.

Here, the term "peelable" refers to the film A of the present invention.
It means that the peeling force between the substrate and the support film is 10 g / cm or less. When the peeling force is 5 g / cm or less, more preferably 3 g / cm or less, when the biaxially stretched film of the present invention is extremely thin, it is preferably substantially free from damage, and is preferably 0.3 g / cm. The above is preferable in that a trouble of peeling when processing with a support film or the like is prevented.

The main component of the material of such a support film is a resin whose difference ΔSP from the solubility parameter of resin A in the solubility parameter SP value is 0.5 or more (hereinafter referred to as resin B). From the viewpoint of releasability.

It is preferable that the film A and the support film are laminated by coextrusion from the viewpoint of facilitating the production.
In this case, the melting point Tmb of the resin B is the melting point Tma of the resin A.
△ Tm is 100 ° C. or less, more preferably 50 ° C. or less. Further, the melt viscosity ratio should be 0.25 or more and 4.0 or less in order to regulate the flow at the molten polymer merging portion during coextrusion and reduce the thickness unevenness of the biaxially stretched film composed of the resin composition (A). Preferably, there is. Here, the conditions for measuring the melt viscosity are measured at the higher temperature of Tmb or Tma + 30 ° C, and the shear rate is 200.
sec- ¹ .

In the present invention, preferred resins A and B
The following examples can be shown as combinations of.

[0030]

[0031]

The resin A is polyphenylene sulfide
Preferably , the resin B is a polyester such as polyethylene terephthalate or polyethylene naphthalate having a melting temperature of 260 ° C. or higher. Of these, polyethylene terephthalate is preferred from the viewpoint of easy production of a laminated film .

The resin composition (B) is a resin composition containing 70% by weight or more, preferably 85% by weight or more of the resin B as exemplified herein. Less than 30% by weight, preferably 15
If the amount is less than% by weight, various additives such as a stabilizer, an antiadhesive, and inert particles may be contained. Particularly, in order to enhance the releasability between the biaxially stretched film made of the resin composition (A) and the support film made of the resin composition (B), a substance incompatible with the resin B is added as a release agent. Is preferred.

Although the resin composition (B) may contain inert particles, it is not possible to add inert particles having an average particle diameter exceeding the thickness t of the biaxially stretched film made of the resin composition (A). The biaxially stretched film made of the resin composition (A) may be undesirably damaged.

Next, a method for producing the biaxially stretched film of the present invention will be described.

The production of the crystalline thermoplastic resin of the present invention can employ any method known in the art . Polyphenylene sulfide is obtained by reacting an alkali sulfide with p-dihalobenzene in a polar solvent at high temperature and high pressure. In particular, it is preferable to react sodium sulfide with p-dichlorobenzene in an amide polar solvent such as N-methyl-2-pyrrolidone. At this time, in order to adjust the degree of polymerization, a polymerization aid such as an alkali metal, a hydroxide or an alkali metal salt of a carboxylic acid is added at 230 ° C. to 28 ° C.
Most preferably, the reaction is performed at 0 ° 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 and the desired degree of polymerization. After the polymerization is completed, the system is gradually cooled to precipitate a polymer, and a slurry formed by pouring the polymer into water or a polar solvent is filtered by a filter, washed with water or an organic solvent, and dried to obtain a polyphenylene sulfide powder. Obtainable. The inert particles can be added at any of these stages by any addition method, but the inert particles dispersed in the liquid are mixed with the polyphenylene sulfide powder and a high-speed stirring means such as a Henschel mixer is used. After the mixture is uniformly mixed, the obtained mixture is supplied to an extruder having at least one-stage vent hole, and after melt-kneading in the extruder, the liquid component is removed from the vent hole. Extruded from
A method of obtaining a polyphenylene sulfide composition in which inert particles are finely dispersed is preferable from the viewpoint of preventing generation and mixing of coarse particles. The liquid used for slurrying the inert particles preferably has a boiling point of 180 ° C to 290 ° C,
180 ° C to 250 ° C is particularly preferred. In particular,
Ethylene glycol and N-methyl-2-pyrrolidone are preferred.

The thus obtained crystalline thermoplastic resin composition containing inert particles can be biaxially stretched as it is or by mixing it with plain pellets containing no particles. For the biaxial stretching, a well-known method (for example, described in JP-A-55-11235) is employed. That is, the crystalline thermoplastic composition pellets in which the inert particles are dispersed are mixed with plain pellets made of a crystalline thermoplastic resin containing no inert particles or supplied to an extruder and melted. And then cast on a cooling drum to form an unstretched sheet. The unstretched sheet is vertically and horizontally placed in a temperature range of (glass transition temperature of thermoplastic resin −10 ° C.) to (glass transition temperature of thermoplastic resin + 30 ° C.). The biaxially oriented film of the present invention can be obtained by simultaneously or sequentially stretching the film by preferably at least 4 times in area ratio, and further performing heat treatment under tension at a temperature of 180 ° C. or more and a melting point or less.

The film of the present invention can be produced by the conventional ordinary film forming method as described above. However, since the film is extremely thin, the film is formed with a support film as described above. Depending on the method, a method of performing a process such as vapor deposition and then peeling off at the time of use may be employed.

In the present invention, as described above, lamination by co-extrusion is performed by laminating the biaxially stretched film of the present invention and the biaxially stretched film of the present invention with a support film (hereinafter referred to as a laminated film). Preferred over controls. In lamination by co-extrusion, resin composition (A) serving as film A and resin composition (B) serving as support film
Are supplied to separate melt extruders and are preferably combined and laminated in a polymer flow path between the melt extruder and a die outlet (so-called lip). That is, the resin composition (A) and the resin composition (B) which were supplied to separate melt extruders and heated and melted to the melting points of the individual compositions or higher were provided between the extruder and the die outlet. Two or three layers are laminated in a molten state by a merging device and extruded from a slit-shaped die outlet. The melted laminate is cooled below the glass transition point of the resin composition (A) and the resin composition (B) on a rotary cooling drum to obtain a substantially amorphous laminated sheet. As the melt extrusion device, a known device can be applied, but an extruder is simple and preferable. Depending on the configuration of the laminated film, the merging apparatus has two layers (resin composition (A) / resin composition (B)) or three layers (resin composition (A) / resin composition (B) / resin composition (A)). ) Has a function of laminating in a molten state.

Next, the amorphous laminated sheet is biaxially stretched at a temperature equal to or higher than the glass transition temperature of the resin composition (B), preferably equal to or higher than a temperature obtained by subtracting 25 ° C. from the glass transition temperature of the resin composition (A). The biaxially oriented film with a support film of the present invention is obtained by biaxially orienting and further heat treatment at a temperature lower than the melting point of the resin composition (A). The magnification for biaxial stretching is preferably 10 times or more in terms of area magnification (longitudinal magnification × horizontal magnification), and the stretching ratio (longitudinal magnification / horizontal magnification) is preferably 0.5 or more and 2.0 or less. In addition, if necessary, 0 to 5
Restriction contraction (relaxation) in the range of 20% is acceptable.

The biaxially stretched film of the present invention is suitably used for a metallized film capacitor. At this time, the method of manufacturing the capacitor is not particularly limited. When a support film is provided, the step of peeling the biaxially stretched film of the present invention from the support film layer is not particularly limited. Hereinafter, a method for manufacturing a capacitor when the film of the present invention is used for a capacitor will be exemplified, but it goes without saying that the present invention is not limited thereto.

Typical capacitors include metallized film capacitors and foil-wound capacitors. A foil-wound capacitor is made by winding and laminating a film and a metal foil alternately, and a metallized film capacitor is obtained by forming a metal thin film typified by a vapor-deposited film on the film and obtaining a metalized film. , To manufacture capacitors.

Since it is easy to obtain an extremely thin film of the film of the present invention which is advantageous for miniaturization of a capacitor, it is preferable to use a metallized film capacitor which can be miniaturized even in the form of a capacitor. There are the following methods for manufacturing a metallized film capacitor.

First, a metal thin film is formed on a biaxially stretched film (hereinafter simply referred to as a film) of the present invention by a method such as vapor deposition or sputtering of a metal such as aluminum, zinc, copper or nickel to obtain a metallized film. At this time, the film may be masked with a tape, oil, or the like, and a non-evaporated portion running in the longitudinal direction of the film, that is, a so-called margin may be provided. Alternatively, a margin can be provided by metallizing the entire surface of the film and then removing the deposited film using a laser beam, discharge, or the like. Thereafter, a slit is formed in a tape shape on which a non-deposition portion runs left or right. At this time, the film can be slit so that the left or right end is a non-deposited portion, or a so-called inner margin type in which the non-deposited portion runs slightly inside the left or right end of the film. . Next, the obtained two tape-shaped metallized films having left and right margins are wound one upon another so that the non-margin ends slightly protrude outward. There is also a method of forming a vapor-deposited film on both sides and winding a double-sided metallized film and a non-metallized film in which margins are formed at different ends on both sides. When a wound capacitor is obtained, it is wound on a shaft with a small diameter of about several mm, and when a multilayer capacitor is obtained, it is wound on a wheel-shaped shaft with a diameter of about tens of cm, or a flat shaft with a length of about tens of cm. It is common.
The obtained wound body is heated and pressed before or after being removed from the winding shaft to form a capacitor element or a capacitor mother element. It can also be preformed during winding with a heating press roller or the like. In this case, it is also preferable to improve the adhesion between the metallized films by a method such as electric discharge treatment, coating, or formation of an easily adhesive layer on the metallized surface and the non-metallized surface of the metallized film. The obtained capacitor element or capacitor mother element is provided with an external electrode electrically connected to a metal thin film on a film serving as an internal electrode by a method such as metal spraying or application of a conductive resin. The capacitor mother element is thereafter cut into individual elements so as to have an optimum capacity, thereby forming a capacitor element. After that, if necessary, heat treatment process, impregnation process with resin or wax etc. by immersion under vacuum or for a long time, lead wire mounting process, resin molding, resin coating, film and sheet pasting etc. Becomes

[0045] Further full Irumu resin A Ru Ah with polyphenylene sulfide has no leads because it has a high heat resistance can be used as a so-called chip capacitors. In this case, the exterior is preferably as simple as possible in terms of miniaturization of the capacitor, and it is preferable to apply a high heat-resistant resin such as polyimide or epoxy to the cut surface of the element, or to attach a high heat-resistant film such as a polyimide film. It is. Further, it is preferable to perform a heat treatment at a temperature of 200 ° C. or more and 265 ° C. or less for one hour or more after the film is wound and at any stage until a capacitor is formed, preferably after the external electrodes are provided, because the characteristics of the capacitor are stabilized. .

Means for obtaining higher production efficiency include winding a wide film so as to obtain a plurality of elements in the width direction of the film, or slitting the wide film immediately before winding so as to obtain a plurality of elements. There is also a method of winding a plurality of tape-shaped metallized films on a single winding shaft. Also in this case, any of a method of laminating two or more single-sided metallized films and a method of laminating a double-sided metallized film and a non-metallized film can be employed. Furthermore, there is a method of winding a single-sided metallized film in which a margin position is alternately moved for each winding turn. The shape of the winding shaft includes a columnar shape and a flat shape as described above. These methods are particularly effective when obtaining a multilayer capacitor. In these methods, a method in which a margin is provided by a laser beam or the like before or during winding of a metallized film deposited on the entire surface of the film is preferably used due to the problem of margin positional accuracy at the time of winding. As the margin, an inner margin type margin is preferably used so that adjacent capacitor elements do not adversely affect each other. The winding body having a plurality of capacitor element precursors in the width direction obtained in this manner is molded by heating and pressing before or after being removed from the winding shaft, and cut in the width direction. By dividing, a capacitor element or a capacitor mother element is obtained. The plate-shaped winding shaft is advantageous in that a parallel plate press that can be pressed with high accuracy without removing the wound body from the winding shaft can be performed. Also, if a method of preforming during winding with a heating press roller or the like is adopted, the film will not be separated even if the winding body is removed from the winding shaft, so that a parallel plate press can be performed. Also, when dividing in the width direction by cutting after winding,
The cut surface on which the external electrode is to be provided is relatively smooth, and the electrical and mechanical connection between the external electrode and the internal electrode (metal thin film) may be weak. It is preferable to take measures for strengthening the contact between the external electrode and the internal electrode by a physical or chemical method. As such a technique, a method is provided in which a cut portion (a hole, a dent, or the like) is provided along a predetermined cutting line in a film before winding so that a cut surface has concavities and convexities as a result,
There are a method of forming irregularities on the cut surface by a method such as plasma etching and sand blast, and a method of chemically bonding easily by a discharge treatment. The capacitor element or the capacitor mother element obtained in this way is converted into a capacitor through the same steps as described above.

When the film of the present invention is provided with a support film in the above-described capacitor manufacturing process, the step of peeling the film A from the support film layer may be any step. The wound film A may be once wound up before moving to the next step. In this case, the film A may be wound while inserting a slip sheet between the film layers in order to avoid damage to the film A.
This method is particularly effective when used in a portion where the film may be deformed, such as after forming a margin by vapor deposition or laser.

In the step of peeling the film A from the support film layer, first, the film A is peeled from the support film layer to obtain a single film A, and then the method of manufacturing the capacitor is as follows. There is an advantage that the process can use the conventional capacitor manufacturing process as it is. In addition, a method of manufacturing a capacitor after performing only evaporation in a laminated film state and obtaining a metalized film A by peeling after evaporation is performed in a state in which a film is deposited with a support layer. Can be minimized. Also, the conventional process can be used as it is for the capacitor manufacturing process. However, from the viewpoint of the productivity of the capacitor, handling of the film A after peeling becomes more difficult as the film thickness becomes thinner. In particular, when there is a step of slitting into a narrow width before winding, a method of slitting before peeling is preferably used in order to improve slit accuracy. Also,
When a margin is formed by a laser beam, a method of forming a margin before peeling is preferably used from the viewpoint of suppressing damage to a film by a laser.
When manufacturing capacitors by either method,
The method of peeling immediately before or simultaneously with the winding is most preferable because there is almost no step of handling the ultrathin film after peeling alone.

[0049]

[Methods for measuring physical properties and effects] Methods for measuring characteristic values and effects according to the present invention are as follows.

(1) Average Particle Size of Particles in Liquid Slurry The slurry was diluted with the same liquid and measured using an optical particle size distribution analyzer (CAPA500, manufactured by Horiba, Ltd.).

(2) Average particle size, particle size distribution coefficient, shape factor of particles The crystalline thermoplastic resin is removed from the film surface by a plasma low-temperature ashing treatment to expose particles near the surface. At this time, a condition under which the particles are not damaged is selected. This is observed with a scanning electron microscope (SEM), and an image of the particles (shading of light generated by the particles) is processed by an image analyzer. The following numerical processing was performed on 5000 or more particles at different observation points, and the average diameter d obtained thereby was defined as the average particle diameter.

D = Σdi / N where di is the equivalent circle diameter of the particles and N is the number.

(3) Relative standard deviation of particle diameter The standard deviation σ (= ｛Σ (d) calculated from the individual particle diameter di, average particle diameter d, and number N of particles measured by the method (2).
id) ² / N｝ ^1/2 ) divided by the average particle size d (σ /
d).

(4) Surface roughness Measured according to JIS-R-0601.

(5) Slip property (static friction coefficient) Measured according to ASTM-1894-63.

(6) Insulation defect of film Electrode made of brass (150 mm × 200 mm, surface roughness 2S
The measurement film (200 mm × 250 mm) was brought into close contact with the following surface and the vapor-deposited surface of the aluminum-deposited polyester film, and the number of insulation defects when a DC voltage of 150 V / μm was applied for 90 seconds was counted.

[0057]

Next, the present invention will be described in detail with reference to examples.

Examples 1 to 4 and Comparative Examples 1 to 7 (1) Polymerization of polyphenylene sulfide 32.6% sodium sulfide was added to a stainless steel autoclave.
kg (250 mol, including 40 wt% of water of crystallization), 100 g of sodium hydroxide, 36.1 kg of sodium benzoate
(250 mol) and 79.2 kg of N-methyl-2-pyrrolidone (hereinafter referred to as NMP), and after dehydration at 205 ° C., 37.5 kg of 1,4-dichlorobenzene (27.5 kg) was added.
55 mol) and 20.0 kg of NMP were added and reacted at 265 ° C. for 4 hours. The reaction product was washed with water and dried to obtain 21 kg of PPS powder having a melt viscosity of 3300 poise.

(2) Preparation of Polyphenylene Sulfide Composition An average diameter of 0.3 was added to 100 parts by weight of the PPS powder obtained above.
10 parts by weight of an ethylene glycol slurry of 50 μm spherical calcium carbonate (solid content concentration: 50%) was added, and the mixture was rapidly stirred at 50 ° C. using a Henschel mixer.

This mixture was fed to a counter-rotating twin-screw extruder having a single-stage vent hole, where it was melted at 310 ° C., and ethylene glycol was removed from the molten resin at the vent. Thereafter, the molten polymer was extruded from a 3 mmφ die, quenched, and then cut into pellets to obtain a polymer (PPS-A) containing 5.0% by weight of spherical calcium carbonate.

Similarly, pelletization was performed in the same manner as described above except that the particles were changed, and the PPS as shown in Table 1 was used.
-B to M were obtained.

The PPS-AM pellets were mixed to prepare a polyphenylene sulfide composition as shown in Table 2.

(3) Film formation The polyphenylene sulfide composition obtained in (2) was mixed with 4
Melted at 310 ° C with an extruder of 0 mm diameter,
After filtering with a 95% cut hole diameter 10 μm filter using a metal fiber, it is extruded from a T-die having a linear lip with a length of 400 mm and a gap of 1.5 mm, and cast on a metal drum whose surface is kept at 25 ° C. Cool and solidify, thickness 2
An unstretched film of 5 μm was obtained. The film was heated at a film temperature of 100 by a longitudinal stretching device comprising a group of rolls.
C., stretching 3.7 times at a stretching speed of 30,000% / min,
Subsequently, using a tenter, at a temperature of 100 ° C. and a stretching speed of 100
The film was stretched 3.4 times at 0% / min, and further heat-treated under tension at 270 ° C. for 10 seconds in a subsequent heat treatment room in the same tenter to obtain a biaxially oriented PPS film having a thickness of 1 μm.
Tables 1, 2 and 3 show the composition and evaluation results of this film.

Example 5, Comparative Example 8 A mixture of PPS-A, E and M, and polyethylene terephthalate having an intrinsic viscosity of 0.7 were supplied to separate extruders, and a double-pipe type melted state was provided at the top of the die. PPS-A, PPS-E and P
The mixture is guided to a mixture of PS-N, then discharged from a T-die die provided and quenched by a cooling rotary drum to obtain a substantially amorphous polyphenylene sulfide resin composition / polyethylene terephthalate / polyphenylene sulfide resin composition Was obtained.

Next, the laminated sheet is run in contact with a plurality of heating rolls having a surface temperature of 90 ° C., and is longitudinally moved between the heating rolls and a cooling roll of 30 ° C. provided at a different peripheral speed next to the heating rolls. The film was stretched 7 times. This uniaxially stretched sheet is stretched 3.5 times at 100 ° C. in a direction perpendicular to the longitudinal direction using a tenter, and then heat-treated at 215 ° C. for 10 seconds to have a thickness of 3.0 μm.
Thus, a biaxially stretched film composed of a polyphenylene sulfide composition having a thickness of 0.6 μm and laminated on a support film of polyethylene terephthalate was obtained. The peeling force of this laminated film was 2.9 g / cm, which was within an appropriate range.

Next, a biaxially stretched film made of a polyphenylene sulfide composition having a thickness of 0.6 μm was obtained by using a continuous peeling and winding machine while peeling the support film from the obtained laminated film. Tables 1, 2 and 3 show the composition and evaluation results of this film.

[0067]

[0068]

[0069]

[Table 1]

[Table 2]

[Table 3]

[0070]

As described above, the biaxially stretched film of the present invention contains two different types of inert particles having a specific relationship between the film thickness, the average particle diameter and the content. Although it is an ultra-thin film, it is excellent in practical properties such as handleability and electrical properties of the film, and has a feature that there are few pinholes.

Accordingly, the biaxially stretched film of the present invention is preferably used not only in the field of films such as dielectrics for capacitors, electric insulating materials, base films for magnetic recording media, but also as fibers and other molded products.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI C08L 81:02 (56) References JP-A-2-252226 (JP, A) JP-A-63-141308 (JP, A) JP-A-1 JP-A-2-266726 (JP, A) JP-A-2-218726 (JP, A) JP-A-2-251538 (JP, A) JP-A-4-62136 (JP, A) JP-A-4-255208 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) C08J 5/18 B32B 27/20 H01G 4/18 C08L 81/02

Claims (4)

(57) [Claims] 1. A main component of polyphenylene sulfide
A biaxially stretched film comprising a crystalline thermoplastic resin composition, wherein the resin composition contains two types of inert particles having different particle sizes so as to satisfy the following formulas (1) to (3). A biaxially stretched film. 0.15 ≦ D ₁ /t≦0.60 (1) 0.70 ≦ D ₂ /t≦1.1 (2) 0.30 ≦ c ₁ · D ₁ + c ₂ · D ₂ ≦ 0.50 (3 ) D ₁ : Average particle size of first inert particles (μm) D ₂ : Average particle size of second inert particles (μm) t: Average thickness of biaxially stretched film (μm) c ₁ : First C ₂ : Weight content of _second inert particles (%) c ₂ : Weight content of second inert particles (%) 2. The biaxially stretched film according to claim 1, wherein at least one of the inert particles has a relative standard deviation of an area circle equivalent diameter represented by the following formula (4) of 1.0 or less. σ / d = {(di−d) ² / N} ^1/2 / d (4) (where di is the circle equivalent diameter of each particle of one inert particle, and d is one inert particle) And N is the number.) 3. The biaxially stretched film according to claim 1, wherein the inert particles are calcium carbonate, silica or crosslinked polystyrene particles. 4. The biaxially stretched film has an average thickness of 0.2 μm.
The biaxially stretched film according to claim 1, wherein the thickness is not less than m and not more than 2 µm .