JP5484713B2 - Polyphenylene sulfide resin film and method for producing the same - Google Patents

Description

  The present invention relates to a polyphenylene sulfide-based resin film containing syndiotactic polystyrene and a method for producing the same. More specifically, the present invention relates to a technique for improving the physical properties of a polyphenylene sulfide resin film.

  Polyphenylene sulfide (PPS) film has excellent heat resistance, chemical resistance, moisture resistance and various electrical properties, so it can be used for adhesive film substrates, release films, film capacitors, circuit boards, etc. It is used for various purposes.

  Conventionally, various studies for improving the characteristics of PPS films have been made (see Patent Documents 1 to 4). For example, in the polyarylene sulfide resin composition described in Patent Document 1 and the polyarylene sulfide-based oriented molded product described in Patent Document 2, molding is performed by blending a predetermined amount of a styrene polymer having a syndiotactic structure. We are trying to improve the performance.

  Patent Document 3 discloses a PPS film having improved dimensional stability when used as a circuit board by blending 50 to 70% by mass of a liquid crystalline resin such as a liquid crystalline polyester resin with a PPS resin. Has been.

  On the other hand, in Patent Document 4, a PPS resin and a polyester resin having a main structural unit of polyethylene terephthalate (PET) are phase-separated by spinodal decomposition to obtain a structural period of 0.001 to 2 μm. A film in which the amount of PPS resin used is reduced by reducing the heat resistance and the like by forming a two-phase continuous structure or a dispersed structure having a distance between particles of 0.001 to 2 μm is disclosed.

Japanese Patent Laid-Open No. 2-70754 JP-A-2-175228 JP 2004-96040 A Japanese Patent Laid-Open No. 2004-231909

  However, the biaxially stretched film composed of the polyarylene sulfide resin composition described in Patent Documents 1 and 2 is excellent in moldability, but has not been studied for handling properties, and the film is not distorted. There is a problem. Moreover, since the PPS film described in Patent Document 3 is an unstretched film, there is a problem that it is not distorted and is difficult to handle. Furthermore, since the PPS film described in Patent Document 4 is a biphasic continuous structure including a polyester resin having PET as a main structural unit, the heat resistance, which is a characteristic of PPS, is reduced and the film can be sufficiently stretched. There is a problem that it becomes impossible.

  As described above, various studies have been made on conventional PPS films, but the problem of lack of strain and poor handleability has not yet been solved.

  Therefore, the main object of the present invention is to provide a polyphenylene sulfide-based resin film excellent in handleability and a method for producing the same.

The polyphenylene sulfide-based resin film according to the present invention is an extruded product of a polyphenylene sulfide-based resin composition in which 0.8 to 30 parts by mass of syndiotactic polystyrene is blended with 100 parts by mass of polyphenylene sulfide. ~ 100 ° C, longitudinal stretching ratio: 3.0-4.0 times, transverse stretching ratio: 2.4-3.4 times, obtained by sequential biaxial stretching, thickness 20-100 μm The polyphenylene sulfide has a melt viscosity of 20 to 2000 Pa · s when measured at a temperature of 310 ° C. and a shear rate of 1200 / sec, and a syndiotactic polystyrene phase is distributed in an island shape with a thickness of The average aspect ratio of the syndiotactic polystyrene phase in the cross section parallel to the direction is 10 or more That.
In this resin film, the thickness is set to 20 to 100 μm, the syndiotactic polystyrene phase is distributed in an island shape, and the average aspect ratio of the syndiotactic polystyrene phase in a cross section parallel to the thickness direction is set to 10 or more. Therefore, the strain becomes stronger.

The method for producing a polyphenylene sulfide-based resin film according to the present invention is based on 100 parts by mass of polyphenylene sulfide having a melt viscosity of 20 to 2000 Pa · s when measured at a temperature of 310 ° C. and a shear rate of 1200 / sec . A polyphenylene sulfide-based resin composition containing 0.8 to 30 parts by mass of syndiotactic polystyrene is melted and extruded at 280 to 340 ° C., and the extruded product is stretched at a temperature of 86 to 100 ° C. in the machine direction. Stretch ratio: 3.0 to 4.0 times, transverse direction stretch ratio: 2.4 to 3.4 times, sequentially biaxially stretched, the thickness is 20 to 100 μm, and the syndiotactic polystyrene phase is an island. The syndiotactic polystyrene phase has an average aspect ratio of 10 or more in a cross-section that is distributed in a shape parallel to the thickness direction. Get a film.
In the method for producing a resin film of the present invention, the extrudate is biaxially stretched at a specific temperature and magnification, and the film has a thickness of 20 to 100 μm. Therefore, the syndiotactic polystyrene phase is distributed in islands, A polyphenylene sulfide-based resin film having an average aspect ratio of the syndiotactic polystyrene phase in a cross section parallel to the thickness direction of 10 or more and a strong stiffness can be produced.

  According to the present invention, the thickness is 20 to 100 μm, the syndiotactic polystyrene phase is distributed in an island shape, and the average aspect ratio of the syndiotactic polystyrene phase in a cross section parallel to the thickness direction is 10 or more. Therefore, a polyphenylene sulfide-based resin film having a strong strain and excellent handleability can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail. The present inventor has conducted extensive experiments to solve the above-described problems, and has obtained the following knowledge. When syndiotactic polystyrene (hereinafter abbreviated as s-PS) is blended with polyphenylene sulfide (PPS), release properties, moldability, etc. without deteriorating the excellent properties of PPS such as heat resistance and chemical resistance. The inferior property of PPS can be improved. However, since PPS and s-PS have different glass transition temperatures and are incompatible with each other, a resin composition in which these are mixed is likely to generate voids and breaks during film formation. In particular, when the film thickness is in the range of 20 to 100 μm, it is difficult to uniformly transmit heat in the thickness direction so that voids and breakage do not occur, and to uniformly stretch both PPS and s-PS. .

  Therefore, the present inventor has studied the conditions for obtaining a film that does not cause voids or breakage during film formation and has no uneven characteristics even when the film thickness is in the range of 20 to 100 μm. As a result, a film formed by blending a specific amount of s-PS with PPS and molded under specific conditions has an s-PS phase distributed in islands, an average aspect ratio of a certain value or more, and a constant average void value. It was found that a strong strain unprecedented was obtained below the value.

  That is, the PPS resin film of the present invention is formed by stretching a PPS resin composition containing 0.8 to 30 parts by mass of s-PS with respect to 100 parts by mass of PPS, and has a thickness of 20 The s-PS phase is distributed in an island shape at ˜100 μm, and the average aspect ratio of the s-PS phase in the cross section parallel to the thickness direction is 10 or more. Hereinafter, the reason for the numerical limitation in the PPS resin film of the present invention will be described.

s-PS compounding amount: 0.8 to 30 parts by mass of PPS with respect to 100 parts by mass of PPS is a main component of the PPS resin film of the present invention, and is an important component for ensuring heat resistance and chemical resistance. is there. Moreover, s-PS has the effect which strengthens the strain of a film by distributing uniformly in island shape. However, when the amount of s-PS compounded in the PPS resin composition is less than 0.8 part by mass, s-PS is difficult to uniformly disperse, and the film characteristics tend to be non-uniform. On the other hand, when the amount of s-PS compounded exceeds 30 parts by mass, the amount of PPS in the composition is reduced, so that heat resistance and chemical resistance are lowered, moldability is also lowered, and breakage occurs during transverse stretching. Sometimes. Therefore, the amount of s-PS compounded in the PPS resin composition is 0.8 to 30 parts by mass with respect to 100 parts by mass of PPS.

  In addition, it is preferable that the s-PS compounding quantity in a PPS resin composition is 1.0-25 mass parts, More preferably, it is 1.2-20 mass parts. By setting the s-PS content in this range, the average aspect ratio of the s-PS phase, which will be described later, can be set to a certain value or more, and the average void value can also be made to be a certain value or less. can do.

Film thickness: 20-100 μm
The PPS resin film of the present invention can be used as, for example, a release film. However, in such applications, since it is required to have strength and strength that can withstand the force applied when peeling, a certain thickness or more is required. It becomes. Specifically, when the thickness of the film is less than 20 μm, the strain is weak and workability is lowered. On the other hand, if the thickness of the film exceeds 100 μm, it becomes difficult for heat to be uniformly transmitted to the entire film during stretching, and film formation itself becomes difficult. Therefore, the thickness of the PPS resin film is set to 20 to 100 μm.

  In addition, it is preferable that film thickness shall be 22.5-80 micrometers, More preferably, it is 30-70 micrometers. Thereby, the strain of the film becomes strong, and workability at the time of use can be improved. In order to obtain a film having such a thickness, for example, the stretching ratio in the longitudinal direction is 3.0 to 4.0 times, the stretching ratio in the transverse direction is 2.4 to 3.4 times, and biaxial stretching. do it.

Average aspect ratio of s-PS phase in cross section parallel to thickness direction: 10 or more In the PPS resin film of the present invention, the s-PS phase is distributed in an island shape, and the cross section parallel to the thickness direction is taken. In this case, the average aspect ratio of the s-PS phase in the range of 1/3 to 2/3 in the thickness direction from the film surface and a length (width) of 300 μm is 10 or more. Thereby, the strain of the film can be made stronger. On the other hand, when the average aspect ratio of the s-PS phase in the region described above is less than 10, even if a predetermined amount of s-PS is blended, the effect of improving the strain is not sufficient, and a strong film cannot be obtained. In addition, the average aspect ratio in this invention is the value which averaged the aspect ratio (major axis diameter / minor axis diameter) of each s-PS phase which exists in the area | region mentioned above. Moreover, what is necessary is just to make extending | stretching temperature into 86-100 degreeC, for example in order to make the average aspect-ratio of this s-PS phase 10 or more.

  Furthermore, in the PPS resin film of the present invention, it is desirable that the average void value in a cross section parallel to the thickness direction is 70% or less. When taking a cross section parallel to the thickness direction, if the average void value exceeds 70% in the range of 1/3 to 2/3 in the thickness direction from the film surface and the length (width) of 300 μm. This is because the strength of the material may decrease. The average void value in the present invention is a value obtained by averaging each void value obtained from the following formula 1 based on the major axis diameter of the voids existing in the above-described region and the major axis diameter of the s-PS phase (n = 10). ). Moreover, what is necessary is just to make extending | stretching temperature into 86-100 degreeC, for example in order to make this average void value 70% or less.

  Next, the structure of PPS which is the main component of the PPS resin film of the present invention will be described. PPS is a polymer having p-phenylene sulfide represented by the following chemical formula 1 as a repeating unit. The PPS used in the present invention preferably contains 70 mol% or more of p-phenylene sulfide units as repeating units in the polymer. When the p-phenylene sulfide unit is less than 70 mol%, the crystallinity and glass transition point of the polymer are lowered, and thus the heat resistance and mechanical strength, which are the characteristics of the polymer film containing PPS as a main component, are not sufficiently exhibited. Because there is. The p-phenylene sulfide unit is more preferably contained in 90 mol% or more.

  In addition to the p-phenylene sulfide unit, PPS may contain a repeating unit having a polymerizable sulfide bond as long as it is less than 30 mol%, preferably less than 10 mol%, among the repeating units of the polymer. Good. The repeating unit having a polymerizable sulfide bond is not particularly limited, but an aromatic sulfide unit represented by the following chemical formula 2 is particularly preferable. In addition, Ar in the following chemical formula 2 represents each functional group represented by the following chemical formulas 3-8. Moreover, Q in the following chemical formula 6 represents a halogen atom or a methyl group, and m represents an integer of 1 to 4. Furthermore, the PPS in the present invention may contain one of these repeating units alone or in combination of two or more.

  On the other hand, when PPS is a copolymer containing a monomer unit represented by the chemical formula 2, the polymer may be in any form of a random polymer and a block polymer. Moreover, the monomer unit other than the said Chemical formula 1 may exist in the polymer terminal or near the terminal.

  PPS in the present invention is obtained by, for example, the method described in US Pat. No. 4,645,826, that is, an alkali metal sulfide and dichlorobenzene in a polar solvent such as N-methyl 2-pyrrolidone. Under certain conditions, it can be obtained by a specific two-step temperature rising polymerization method. By applying this polymerization method, a substantially linear and high molecular weight PPS can be obtained. Further, by adding a small amount of an aromatic halogen compound having 3 or more halogen substituents at the time of polymerization, it is possible to obtain a PPS having some branched or crosslinked structure.

  The melt viscosity of PPS is preferably 20 to 2000 Pa · s when measured at a temperature of 310 ° C. and a shear rate of 1200 / sec. When the melt viscosity is less than 20 Pa · s, the mechanical properties and heat resistance of the film are lowered, and the characteristics as a PPS film may not be obtained. When the melt viscosity exceeds 2000 Pa · s, the extruder This is because the addition of a manufacturing device such as a filter or a filtration device may increase, causing problems. The melt viscosity of the PPS is more preferably 30 to 1800 Pa · s. The shear rate here is a value defined as a gradient rate when a viscous fluid passes between parallel plates.

  Next, s-PS added to the PPS resin composition forming the PPS resin film of the present invention will be described. s-PS is a styrene polymer mainly having a syndiotactic structure represented by the following chemical formula 9 in a repeating unit. The syndiotactic structure refers to a three-dimensional structure in which phenyl groups and substituted phenyl groups which are side chains are alternately positioned in opposite directions with respect to a main chain formed from carbon-carbon bonds.

  The tacticity of s-PS can be quantitatively analyzed by a nuclear magnetic resonance method using isotope carbon. The tacticity measured by the nuclear magnetic resonance method can be expressed by the existence ratio of a plurality of consecutive structural units. For example, two dyads, three triads, and five pendants. Represented by The s-PS used in the present invention is a polystyrene having a syndiotacticity of 75% or more, preferably 80% or more by dyad, or 30% or more, preferably 50% or more by pentad (racemic pentad), Poly (alkyl styrene), poly (halogenated styrene), poly (alkoxy styrene), poly (vinyl benzoate) or a mixture thereof is desirable, and a copolymer based on these may also be used.

  In addition, s-PS is, for example, a method described in JP-A-62-187708, that is, condensation of a titanium compound and water with a trialkylaluminum in an inert hydrocarbon solvent or in the absence of a solvent. It can be obtained by polymerizing a styrene monomer using the product as a catalyst.

  Next, the manufacturing method of the PPS resin film of this invention is demonstrated. FIG. 1 is a schematic view showing an example of a method for producing a PPS resin film of the present invention. When producing the PPS resin film of the present invention, first, a resin composition containing PPS as a main component is supplied to an extruder to form a pellet. Here, the resin composition containing PPS as a main component is, for example, a resin composition in which additives such as calcium carbonate and calcium stearate are added to PPS as necessary.

  Subsequently, the resin pellets mainly composed of PPS obtained in the above-described process and the resin pellets mainly composed of s-PS are dry-blended at a specific ratio and supplied to the extruder 1 shown in FIG. . In addition, a lubricant, a plasticizer, an antioxidant, an elastomer for impact resistance, and the like may be added to the resin pellet containing s-PS as a main component, if necessary. Moreover, you may perform the blend of PPS and s-PS before pelletizing each.

  In the extruder 1, the supplied resin is melted at 280 to 340 ° C., formed into a sheet with a die, and discharged. At this time, if the melting temperature is less than 280 ° C., PPS is not sufficiently melted, and if the melting temperature exceeds 340 ° C., a decomposition product of the resin is generated during extrusion. Therefore, the melting temperature is 280 to 340 ° C. In this step, it is desirable to filter the molten resin composition using a filter or the like to remove coarse foreign matters such as dust or aggregates of additives. Thereafter, the film discharged from the die is pressed onto the cooling body 2 such as a metal drum to be cooled and solidified to obtain a resin sheet.

  Next, the resin sheet obtained in the above-described process is stretched. In the present invention, the film is formed by stretching in order to impart strength to the film. The release film needs to be strong enough to withstand the force applied when peeling from the substrate material, but unstretched film becomes brittle when heated, so it cannot withstand the strength when peeled, and the film cracks. End up. For this reason, in the present invention, the film is formed by uniaxial or biaxial stretching.

  The PPS resin film of the present invention may be a stretched film, but is more preferably a biaxially stretched film. Here, biaxial stretching refers to stretching in order to give molecular orientation in the longitudinal direction and the transverse direction. Stretching may be performed in two directions separately (hereinafter referred to as sequential biaxial stretching) or simultaneously in two directions. Moreover, you may redraw in the vertical and / or horizontal direction.

  Hereinafter, a method for producing a PPS resin film by sequential biaxial stretching will be described as an example. First, stretching in the longitudinal direction is performed under the following conditions. This stretching in the longitudinal direction is usually performed by the difference in the peripheral speed of the roll. In addition, the stretching may be performed in one stage, or may be performed in multiple stages using a plurality of roll pairs.

Stretching temperature: 86-100 ° C
The temperature of the roll 3 affects the dispersion structure of the s-PS phase, and when the roll 3 is stretched at a temperature of less than 86 ° C., voids increase and the film is lowered. On the other hand, when the roll 3 is stretched at a temperature higher than 100 ° C., the average aspect ratio of the s-PS phase becomes less than 10 and the film is insufficiently strained. Therefore, in this invention, it extends | stretches in the temperature range of 86-100 degreeC.

Longitudinal stretching ratio: 3.0 to 4.0 times the longitudinal draw ratio, flatness of the dispersion structure and the film of s-PS phase, affect the film forming properties. For this reason, when the draw ratio in the longitudinal direction is less than 3.0, the aspect ratio of the s-PS phase becomes small, and the film is insufficiently strained. In addition, stretching unevenness and sagging may occur, and the uniformity of characteristics may be reduced. On the other hand, when the stretching ratio in the longitudinal direction exceeds 4.0 times, the orientation in the longitudinal direction becomes too strong, so that the film tends to be broken when stretched in the lateral direction and film formation becomes difficult. Therefore, in this invention, when extending | stretching longitudinally, a draw ratio shall be 3.0-4.0 times.

  Next, the film stretched in the longitudinal direction by the above-described method and conditions is introduced into the tenter stretching machine 4, and the film is stretched in the transverse direction by pulling the both ends of the film with clips. At this time, the stretching temperature is 86 to 100 ° C. for the same reason as the above-described longitudinal stretching, and the stretching ratio is 2.4 to 3.4 times.

Transverse stretching ratio: draw ratio to 2.4 to 3.4 times the transverse direction, the plane of the dispersion structure and the film of s-PS phase, affect the film forming properties. Specifically, when the stretching ratio in the transverse direction is less than 2.4 times, the aspect ratio of the s-PS phase becomes small, resulting in insufficient film stiffness or uniform properties, as in the stretching in the longitudinal direction. The sex will be reduced. On the other hand, if the stretching ratio in the transverse direction exceeds 3.4 times, breakage tends to occur during stretching, and film formation becomes difficult. Therefore, in this invention, when extending | stretching transversely, a draw ratio shall be 2.4 to 3.4 times.

  Next, after stretching in the transverse direction, the distance between the clips immediately sandwiching the film is reduced by about 0.1 to 10%, preferably about 0.5 to 7%. In the stretching machine, it is preferable to perform the heat setting treatment at a temperature not lower than the stretching temperature and not higher than the melting point. Thereby, a heat-resistant dimension can be stabilized. It is preferable that the temperature of this heat setting process shall be 240-290 degreeC. If the heat setting treatment temperature is less than 240 ° C., the efficiency of relaxation in the transverse direction is lowered, and it may be difficult to obtain a film having excellent dimensional stability at high temperatures, and the heat setting treatment temperature is 290 ° C. This is because exceeding the melting point of the PPS film makes it difficult to form a film. The heat setting treatment temperature is more preferably 250 to 285 ° C.

  And after cooling to the room temperature in the exit part of the tenter extending | stretching machine 4, the film after a heat setting process is wound up with the winder 5, and a biaxially stretched PPS resin film is obtained.

  In addition, also when forming a film by uniaxial stretching, extending | stretching temperature shall be 86-100 degreeC similarly to biaxial stretching mentioned above. When the stretching temperature is less than 86 ° C., many voids are generated, and when the stretching temperature exceeds 100 ° C., the average aspect ratio of the s-PS phase is less than 10, and in each case, sufficient strain is obtained for the film. Because there is no. In addition, when the uniaxial stretching is performed, if the draw ratio is less than 2.4 times, the aspect ratio of the s-PS phase is decreased, the film may be insufficiently strained, and further, uneven stretching and sagging may occur. The uniformity of the film may be reduced. On the other hand, when the draw ratio exceeds 4.0, breakage may occur and film formation may be difficult. Therefore, it is desirable that the draw ratio when uniaxially drawing is 2.4 to 4.0 times.

  As described above, the PPS resin film of the present invention is obtained by stretching a PPS resin composition containing 0.8 to 30 parts by mass of s-PS with respect to 100 parts by mass of PPS, and has a thickness of Since the syndiotactic polystyrene phase is distributed in an island shape at 20 to 100 μm and the average aspect ratio of the syndiotactic polystyrene phase in the cross section parallel to the thickness direction is 10 or more, the strain is strong. As a result, the handleability can be improved as compared with the conventional PPS film.

  Hereinafter, the effects of the present invention will be specifically described with reference to Examples and Comparative Examples of the present invention. In this example, the PPS resin films of Examples 1 to 3 within the scope of the present invention and the PPS resin films of Comparative Examples 1 to 4 deviating from the scope of the present invention were prepared by the following methods. Furthermore, as a reference example, a PPS film not containing s-PS was produced. In addition, this invention is not limited to the Example shown below.

Example 1
First, calcium carbonate having a mean particle size of 0.7 μm as a filler (“NITREX” manufactured by Nitto Flour & Chemical Co., Ltd.) # Relative to 100 parts by mass of PPS (“Fortron KPS (registered trademark)” W312) manufactured by Kureha 30PS) and 0.2 parts by mass of calcium stearate were added to prepare a resin pellet mainly composed of PPS obtained by pelletizing a mixed powder.

  Next, 1.2 parts by mass of s-PS resin pellets (“XAREC (registered trademark)” S-104 manufactured by Idemitsu Kosan Co., Ltd.) is blended with 100 parts by mass of the prepared resin pellets, and mixed using a blender. A PPS resin composition was obtained.

  Next, this PPS resin composition was melted by heating to 310 ° C. using an extruder having a diameter of 50 mm, and filtered through a disk filter having an opening of 40 μm. Subsequently, the melted PPS resin composition was extruded from a die having a linear lip having a length of 560 mm and a gap of 1.1 mm, and the surface was cast on a metal drum maintained at 40 ° C. to be cooled. A 360 μm resin sheet was prepared.

  Next, the resin sheet was preheated by bringing it into contact with a metal roll whose surface temperature was adjusted to 80 to 90 ° C., and then the length in the vertical direction on the metal roll whose surface temperature was adjusted to 93 ° C. Roll-to-roll stretching was performed so as to be 3.5 times. Subsequently, the film stretched in the longitudinal direction was introduced into a tenter stretching machine, and stretched 2.9 times in the transverse direction in an atmosphere at 93 ° C. Immediately after stretching, the film was heat-set at 250 ° C. for about 100 seconds while being relaxed by about 4% in the transverse direction to obtain a biaxially stretched film (PPS resin film) having a thickness of 40 μm.

(Example 2)
Extruded under the same conditions as in Example 1, using a PPS resin composition in which 6.2 parts by mass of s-PS resin pellets were blended with 100 parts by mass of PPS resin pellets in the same manner as in Example 1 described above. A resin sheet having a thickness of 360 μm was obtained. Next, the resin sheet was stretched in the longitudinal and lateral directions under the same conditions as in Example 1 except that the longitudinal stretching temperature was 97 ° C., and then relaxed to a biaxially stretched film (PPS having a thickness of 40 μm). System resin film).

(Example 3)
In the same manner as in Example 1 described above, a PPS resin composition in which 19 parts by mass of s-PS resin pellets were blended with 100 parts by mass of PPS resin pellets was extruded under the same conditions as in Example 1, and the thickness was A resin sheet having a thickness of 360 μm was obtained. Next, the resin sheet was stretched in the longitudinal and lateral directions under the same conditions as in Example 1, and then relaxed to obtain a biaxially stretched film (PPS resin film) having a thickness of 40 μm.

(Comparative Example 1)
As Comparative Example 1 of the present invention, a PPS resin composition in which 6.2 parts by mass of s-PS resin pellets was blended with 100 parts by mass of PPS resin pellets in the same manner as in Example 1 was used. Extrusion was performed in the same manner as in No. 1 to prepare a resin sheet having a thickness of 200 μm. Next, this resin sheet was stretched 3.5 times in the longitudinal direction and 3.5 times in the transverse direction under the same stretching temperature conditions as in Example 1. Thereafter, relaxation and heat setting were performed in the same manner as in Example 1 to obtain a biaxially stretched film (PPS resin film) having a thickness of 18 μm.

(Comparative Example 2)
As Comparative Example 2 of the present invention, a PPS resin composition in which 6.2 parts by mass of s-PS resin pellets was blended with 100 parts by mass of PPS resin pellets in the same manner as in Example 1 was used. Extrusion was performed in the same manner as in No. 1 to prepare a resin sheet having a thickness of 360 μm. Next, the resin sheet was preheated by bringing it into contact with a metal roll whose surface temperature was adjusted to about 80 ° C., and then 3.5 mm in the vertical direction on the metal roll whose surface temperature was adjusted to 84 ° C. The film was stretched twice. Subsequently, the film was stretched 2.9 times in the transverse direction at 84 ° C. and then relaxed to obtain a biaxially stretched film (PPS resin film) having a thickness of 40 μm. In addition, in this comparative example, it often broke at the time of lateral stretching, and stretching was difficult.

(Comparative Example 3)
As Comparative Example 3 of the present invention, a PPS resin composition in which 6.2 parts by mass of s-PS resin pellets were blended with 100 parts by mass of PPS resin pellets in the same manner as in Example 1 was used. Extrusion was performed in the same manner as in No. 1 to prepare a resin sheet having a thickness of 360 μm. Next, the resin sheet was preheated by bringing it into contact with a metal roll whose surface temperature was adjusted to about 95 ° C., and then 3.5 mm in the vertical direction on the metal roll whose surface temperature was adjusted to 105 ° C. The film was stretched twice. Subsequently, the film was stretched 2.9 times in the transverse direction at 102 ° C. and then relaxed to obtain a biaxially stretched film (PPS resin film) having a thickness of 40 μm. In this comparative example, there was uneven width in which the film width changed periodically.

(Comparative Example 4)
As Comparative Example 4 of the present invention, a PPS resin composition in which 6.2 parts by mass of s-PS resin pellets was blended with 100 parts by mass of PPS resin pellets in the same manner as in Example 1 was used. Extrusion was performed in the same manner as in No. 1 to prepare a resin sheet having a thickness of 360 μm. Next, this resin sheet was stretched 3.5 times in the longitudinal direction and 3.5 times in the transverse direction at the same stretching temperature as in Example 2. However, breakage occurred frequently during stretching, and it was difficult to obtain a film.

(Reference example)
As a reference example of the present invention, a PPS film to which s-PS was not added was produced. Specifically, resin pellets mainly composed of PPS prepared by the same method as in Example 1 described above are melted and filtered by the same method as in Example 1, and then cast to obtain a resin sheet having a thickness of 360 μm. Was made. Next, the resin sheet is preheated by bringing it into contact with a metal roll whose surface temperature is adjusted to about 85 ° C., and then the length in the vertical direction on the metal roll whose surface temperature is adjusted to about 90 ° C. Was stretched between rolls so as to be 3.5 times. Subsequently, the film stretched in the longitudinal direction was introduced into a tenter stretching machine, stretched 2.9 times in the transverse direction in an atmosphere at 92 ° C., and immediately relaxed by about 3% in the transverse direction. Then, it heat-set at 260 degreeC for about 100 second, and obtained the biaxially stretched film (PPS film) with a thickness of 40 micrometers.

  Next, the average aspect ratio and the average void value were measured for the films of Examples, Comparative Examples, and Reference Examples prepared by the above method, and the strain and the alignment uniformity were evaluated. Hereinafter, specific measurement methods and evaluation methods will be described. 2A and 2B are diagrams showing measurement areas of average aspect ratio and average void value. FIG. 2A is a plan view, and FIG. 2B is an enlarged cross-sectional view taken along line AA shown in FIG. is there.

  As shown in FIGS. 2A and 2B, the average aspect ratio and average void value are parallel to the thickness direction and perpendicular to the width direction (TD) as shown in FIGS. 2A and 2B. A cross-sectional SEM (Scanning Electron Microscope) photograph is taken. The average aspect ratio is 1/3 to 2/3 (t / 3) in the thickness direction from the film surface and 300 μm in the film forming direction (MD) based on the cross-sectional SEM photograph of each film. The major axis diameter and minor axis diameter of the existing s-PS phase were measured and calculated. On the other hand, the average void value is similarly 1/3 to 2/3 (t / 3) in the thickness direction from the film surface and 300 μm in the film forming direction (MD) based on the cross-sectional SEM photograph of each film. The major axis diameter of the s-PS phase and the major axis diameter of the voids were measured and calculated using Equation 1 above.

  On the other hand, the strain of each film was evaluated based on the measured loop stiffness. Loop stiffness is the load required to fix a sample in a looped shape in a direction where it is difficult to sag due to its own weight, and to crush the loop by a predetermined amount in the diametrical direction, and the strength of the film is evaluated based on this value. be able to. In this example, a loop stiffness tester manufactured by Toyo Seiki Seisakusho Co., Ltd. was used, the width of the sample was 25 mm, the effective length was 85 mm, the compression speed was 3.5 mm / sec, and the load required to crush the loop by 15 mm was obtained. It was measured. The above results are summarized in Table 1 below.

  As shown in Table 1 above, the PPS resin films of Examples 1 to 3 in which s-PS was blended with PPS within the scope of the present invention had an average aspect ratio of s-PS phase of 10 or more. The stiffness value was higher than that of the PPS film of the reference example, and the stiffness was strong.

  On the other hand, since the PPS resin film of Comparative Example 1 having a film thickness of less than 20 μm was thin and the average aspect ratio of the s-PS phase was also less than 10, the loop stiffness value was extremely low. .

  In addition, the PPS resin film of Comparative Example 2 in which the stretching temperature was less than 86 ° C. had an average aspect ratio of the s-PS phase of less than 10 and an average void value of more than 70%. The value was low, and there was less strain than the PPS film of the reference example. Note that the PPS resin film of Comparative Example 2 had many breaks during transverse stretching and was inferior in moldability.

  On the other hand, the PPS resin film of Comparative Example 3 in which the stretching temperature exceeded 100 ° C. had an average aspect ratio of the s-PS phase of less than 10, resulting in a lower loop stiffness value than the PPS film of the reference example. There was nothing. The PPS resin film of Comparative Example 3 had a large width unevenness and a non-uniform characteristic.

  Furthermore, in Comparative Example 4 stretched in the transverse direction at a magnification exceeding 3.4 times, breakage occurred frequently, and a film having a thickness of 40 μm could not be obtained.

  As described above, in this example, s-PS was added to PPS within the scope of the present invention, and the film was formed by stretching so that the thickness and the average aspect ratio of the s-PS phase were within the scope of the present invention. The PPS resin film was stronger than the PPS resin film of the comparative example and the PPS film of the reference example, which were out of the scope of the present invention. That is, according to the present invention, it was confirmed that a PPS resin film excellent in handleability was obtained.

It is a schematic diagram which shows an example of the manufacturing method of the PPS-type resin film of this invention. It is a figure which shows the measurement area | region of the average aspect-ratio and average void value in the Example of this invention, (a) is a top view, (b) is an expanded sectional view by the AA line shown to (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extruder 2 Cooling body 3 Roll 4 Tenter drawing machine 5 Winding machine

Claims (2)

An extruded product of a polyphenylene sulfide-based resin composition in which 0.8 to 30 parts by mass of syndiotactic polystyrene is blended with 100 parts by mass of polyphenylene sulfide , a stretching temperature: 86 to 100 ° C., and a stretching ratio in the longitudinal direction: 3 It is obtained by sequentially biaxially stretching as 0.0 to 4.0 times and a stretching ratio in the transverse direction: 2.4 to 3.4 times.
The thickness is 20-100 μm,
The polyphenylene sulfide has a melt viscosity of 20 to 2000 Pa · s when measured at a temperature of 310 ° C. and a shear rate of 1200 / second,
Syndiotactic polystyrene phase is distributed in islands,
A polyphenylene sulfide-based resin film, wherein an average aspect ratio of the syndiotactic polystyrene phase in a cross section parallel to the thickness direction is 10 or more. 0.8 to 30 parts by mass of syndiotactic polystyrene was blended with 100 parts by mass of polyphenylene sulfide having a melt viscosity of 20 to 2000 Pa · s when measured at a temperature of 310 ° C. with a shear rate of 1200 / sec. Polyphenylene sulfide-based resin composition is melted at 280 to 340 ° C. and extruded,
The extruded product was successively biaxially stretched at a stretching temperature of 86 to 100 ° C., a longitudinal stretching ratio of 3.0 to 4.0 times, and a transverse stretching ratio of 2.4 to 3.4 times. ,
Polyphenylene sulfide-based resin film having a thickness of 20 to 100 μm, a film in which the syndiotactic polystyrene phase is distributed in an island shape, and an average aspect ratio of the syndiotactic polystyrene phase in a cross section parallel to the thickness direction is 10 or more Manufacturing method.

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