JP2012213983A - Polymer filter, extrusion device, method for manufacturing extrusion molding and method for manufacturing optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer filter that can suppress inclusion of a foreign material in a filtered polymer.SOLUTION: The polymer filter 1 includes: a container body 11 with a polymer inlet 11a and an open part 11b; a base plate 12 attached to the open part 11b of the container body 11; and a plurality of leaf disk type filters 13 disposed in the container body 11 and filtering polymers inflow into the container body 11. The container body 11 includes a polymer outlet 11C for discharging at least a part of polymers passing through the side of the leaf disk type filters 13 without being filtered by the leaf disk type filters 13 in the container body 11 into an outer space of the polymer filter 1.

Description

  The present invention relates to, for example, a polymer filter used for filtering a polymer, which can reduce the amount of foreign matter flowing out, an extrusion apparatus using the polymer filter, a method for producing an extruded product, and an optical film. It relates to the manufacturing method.

  In a liquid crystal display device, an optical film such as a polarizing film or a retardation film is laminated on one or both sides of a liquid crystal cell for the purpose of compensating optical characteristics of the liquid crystal, improving the viewing angle, improving the contrast, or preventing coloring. Yes.

  The optical film is generally produced by forming a thermoplastic resin into a film by a casting (solution casting) method, a calendar method, a melt extrusion method, or the like.

  When obtaining an optical film by the melt extrusion method, a polymer filter is often used to remove foreign substances contained in the molten resin. Moreover, a polymer filter may be used also when obtaining extrusion molded articles other than an optical film.

  As an example of the polymer filter, the following Patent Document 1 includes a bottom portion having a flat inner bottom surface on which a resin delivery port is formed, and a side wall portion having a cylindrical inner side surface perpendicular to the inner bottom surface. And a housing provided on the opposite side of the side wall portion from the bottom portion and having a resin inlet formed therein, and standing on the inner bottom surface in the housing and communicating with the resin delivery port A columnar part mounted on the column part so that a plurality of layers are stacked, and the column part formed with a channel and the molten resin flowing in from the resin inlet are filtered and sent to the channel of the column part. A polymer filter comprising a filter element is disclosed.

  In the polymer filter described in Patent Document 1, the housing includes the inner bottom surface and the inner surface so as to straddle between the inner bottom surface and the inner side surface at a boundary portion between the inner bottom surface and the inner side surface. On the other hand, a convex surface portion having a convex shape toward the center side of the housing is provided. Moreover, in patent document 1, the polymer filter is comprised so that the relationship of following formula (101) and following formula (102) may be satisfy | filled.

0.3 ≦ d ₁ /d≦0.8 Formula (101)
0.3 ≦ d ₂ /d≦0.8 Formula (102)
d represents the distance from the filter element to the inner surface, and d ₁ represents the distance in the radial direction of the inner surface from the inner surface to the point where the inner bottom surface and the convex portion intersect. , d ₂ from the inner bottom surface, to the point where the said inner side surface and the convex surface portions intersect represents the distance in a direction perpendicular to the inner bottom surface.

JP 2011-11395 A

  In patent document 1, the said convex part is provided in the part in which molten resin stagnates. However, even if such a convex surface portion is provided on the housing, the residence of the molten resin may not be sufficiently suppressed. When the molten resin stays in the polymer filter, the molten resin deteriorates in the staying portion and becomes foreign matter. For this reason, a foreign material may be contained in the molten resin which flows out from a polymer filter. As a result, for example, when an extruded product such as an optical film is produced by a melt extrusion method using the polymer filter described in Patent Document 1, there is a problem that an appearance defect is likely to occur in the obtained extruded product. Moreover, in the polymer filter described in Patent Document 1, the residence of the molten resin may not be sufficiently suppressed depending on conditions such as the temperature and flow rate of the resin.

  An object of the present invention is a polymer filter for filtering a polymer, the polymer filter capable of suppressing the inclusion of foreign matter in the filtered polymer, an extrusion apparatus using the polymer filter, and a method for producing an extruded product And it is providing the manufacturing method of an optical film.

  According to a wide aspect of the present invention, there is provided a polymer filter for filtering a polymer, a container main body having a polymer inlet and an open portion, a base plate attached to the open portion of the container main body, and the above A plurality of leaf disk type filters disposed in the container body for filtering the polymer flowing into the container body, and the container body is not filtered by the leaf disk type filter, and the container There is provided a polymer filter having a polymer outlet for discharging at least a part of the polymer that has passed through the side of the leaf disk filter in the body to the outer space of the polymer filter.

  In a specific aspect of the polymer filter according to the present invention, a plurality of the leaf disk filters are inserted into the leaf disk filter and a holding plate that fixes the leaf disk filters so that the leaf disk filters are in contact with each other. And a center post having a polymer flow path for allowing the polymer filtered by the leaf disk filter to flow out to the external space of the polymer filter.

  On the other specific situation of the polymer filter which concerns on this invention, the said container main body has the said polymer discharge port in the edge part by the side of the said open part.

  In another specific aspect of the polymer filter according to the present invention, the container body has a plurality of the polymer outlets.

  In still another specific aspect of the polymer filter according to the present invention, the polymer outlet is disposed at a position where the polymer tends to stay during filtration of the polymer.

  In another specific aspect of the polymer filter according to the present invention, the polymer outlet can be opened and closed.

  In still another specific aspect of the polymer filter according to the present invention, the polymer filter is further provided with a discharge speed control member that is attached to the polymer discharge port and controls the speed at which the polymer is discharged from the polymer discharge port.

  The polymer filter according to the present invention is preferably a polymer filter for an optical film for obtaining an optical film.

  An extrusion apparatus according to the present invention includes an extruder, a polymer filter connected to the tip of the extruder, and a mold connected to the polymer filter, and the polymer filter is configured according to the present invention. It is.

  The extrusion apparatus according to the present invention is preferably an extrusion apparatus that is used to obtain an optical film by forming a polymer into a film by a melt extrusion method.

  The method for producing an extrusion-molded product according to the present invention is a method for producing an extrusion-molded product in which a polymer is molded by a melt-extrusion method, wherein the melted polymer is filtered through a polymer filter and filtered. The polymer filter includes a molding step of extruding a polymer from a mold and molding; and a cooling step of solidifying the molded polymer by cooling to obtain an extruded product. The polymer filter is configured according to the present invention. A polymer filter is used.

  The method for producing an optical film according to the present invention is a method for producing an optical film in which a polymer is formed by a melt extrusion method, a filtration step of filtering a molten polymer through a polymer filter, and a filtered polymer The polymer filter comprising: a film forming step of forming a film by extruding the film from a mold; and a cooling step of solidifying the film formed into a film by cooling to obtain an optical film. As a polymer filter constructed according to the present invention is used.

  A polymer filter according to the present invention is disposed in a container body having a polymer inlet and an open part, a base plate attached to the open part of the container body, and the container body. A plurality of leaf disk filters for filtering the inflow polymer, and the container body is not filtered by the leaf disk filter, and the side of the leaf disk filter is disposed in the container body. Since it has a polymer outlet for discharging at least a part of the polymer that has passed to the outside space of the polymer filter, the filtered polymer can be discharged by discharging at least a part of the polymer from the polymer outlet as necessary during filtration. It can suppress that a foreign material is contained in.

FIG. 1 is a cross-sectional view schematically showing a polymer filter according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II of the polymer filter shown in FIG. FIG. 3 is a schematic configuration diagram showing an example of an extrusion apparatus for forming a polymer by a melt extrusion method.

  Details of the present invention will be described below.

  A polymer filter according to the present invention is disposed in a container body having a polymer inlet and an open part, a base plate attached to the open part of the container body, and the container body. And a plurality of leaf disk filters for filtering the polymer that has flowed in. The container body is not filtered by the leaf disk type filter, and the polymer body for discharging at least a part of the polymer that has passed through the side of the leaf disk type filter in the container body to the external space of the polymer filter. Has an exit.

  Since the polymer filter which concerns on this invention is equipped with the said structure, it can suppress that a foreign material is contained in the polymer filtered by this polymer filter. In particular, the polymer that has passed through the side of the leaf disk filter in the container body without being filtered by the leaf disk filter is likely to stay, and once the retained polymer flows out of the polymer filter, it becomes a foreign substance. There are many. Such a foreign substance becomes a cause of appearance defects in an extruded product such as an optical film obtained when an extruded product such as an optical film is produced by a melt extrusion method using a polymer filter. In particular, in an optical film, mixing of foreign matters becomes a big problem. By using the polymer filter according to the present invention, it becomes difficult for foreign matter to be contained in the filtered polymer, and as a result, an extruded product such as an optical film with few appearance defects can be obtained.

  The polymer filter according to the present invention is inserted into the holding plate for fixing the leaf disk type filter and the leaf disk type filter so that the plurality of leaf disk type filters are in contact with each other. It is preferable to further include a center post having a polymer flow path for allowing the polymer filtered by the filter to flow into the external space of the polymer filter.

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

(Details of polymer filter)
In FIG. 1, the polymer filter which concerns on one Embodiment of this invention is typically shown with sectional drawing. FIG. 2 is a cross-sectional view of the polymer filter shown in FIG. 1 taken along line II of FIG.

  The polymer filter 1 shown in FIGS. 1 and 2 includes a container body 11, a base plate 12, a plurality of leaf disk filters 13, a pressing plate 14, and a center post 15.

  The container body 11 has a polymer inlet 11a and an open portion 11b. A polymer inlet 11 a is provided at one end of the container body 11. An open portion 11 b is provided at the other end opposite to one end of the container body 11. The container main body 11 includes a cylindrical housing 11A and a housing lid 11B attached to one end of the housing 11A. The polymer inflow portion 11a is provided at the center of the housing lid 11B.

  The base plate 12 is attached to the open portion 11 b of the container body 11. The base plate 12 has a through hole 12a in the center. The container body 11 and the base plate 12 may be formed integrally.

  The plurality of leaf disk filters 13 are arranged in the container body 11. The periphery of the leaf disk type filter 13 is surrounded by a container body 11 and is surrounded by a housing 11A and a housing lid 11B. The leaf disk type filter 13 is a filter for filtering the polymer flowing into the container body 11. The plurality of leaf disk filters 13 are in contact with each other.

  The holding plate 14 fixes the leaf disk type filter 13 so that the plurality of leaf disk type filters 13 are in contact with each other. For this reason, the leaf disk type filter 13 is sandwiched between the pressing plate 14 and the base plate 12. The leaf disk type filter 13 may be compressed by the pressing plate 14 and the base plate 12. The holding plate 14 has a through hole 14a.

  The center post 15 is inserted into the inner peripheral portion 13 a of the leaf disk type filter 13. One end of the center post 15 is inserted into the through hole 14 a of the pressing plate 14. Further, the other end of the center post 15 is inserted into the through hole 12 a of the base plate 12. The center post 15 has a polymer flow path 15 a for allowing the polymer filtered by the leaf disk type filter 13 to flow out to the external space of the polymer filter 1. The center post 15 has a cylindrical member, and the polymer flow path 15a is a hollow portion inside the cylindrical member. The cylindrical member is cylindrical. Further, the center post 15 has a plurality of through holes 15b through which the polymer filtered by the leaf disk filter 13 flows into the center post 15 via the inner peripheral portion 13a. The through hole 15b is provided in the cylindrical member.

  A holding screw 16 is attached to the tip portion of the center post 15 located on the holding plate 14 side. That is, a holding screw 16 is attached to the surface of the holding plate 14 opposite to the leaf disk type filter 13 side.

  In the polymer filter 1, the container body 11 is not filtered by the leaf disk type filter 13, and at least a part of the polymer that has passed through the side of the leaf disk type filter 13 in the container body 11 is transferred to the outer space of the polymer filter 1. It has a polymer outlet 11C for discharging. An opening / closing member 11c that can open and close the polymer outlet 11C is attached to the polymer outlet 11C. That is, the container main body 11 has an opening / closing member 11c.

  When the polymer is filtered using the polymer filter 1, the polymer is introduced from the polymer inlet 11 a of the container body 11. The polymer that has flowed in passes through the internal flow path between the holding plate 14 and the container body 11 and moves to the side of the leaf disk filter 13. The polymer that has moved to the side of the leaf disk type filter 13 is usually guided to the inside of the leaf disk type filter 13 while passing through the overlapped gaps of the plurality of leaf disk type filters 13, and is centered in the radial direction. It progresses while being filtered. The polymer filtered by the leaf disk type filter 13 passes through the through hole 15 b of the center post 15 and is guided to the polymer flow path 15 a inside the center post 15. The polymer guided to the polymer flow path 15 a flows out to the outer space of the polymer filter 1. During the filtration, the polymer tends to stay on the side of the leaf disk type filter 13 more downstream than the upstream side in the polymer flow direction. In a place where the polymer tends to stay, the polymer is deteriorated by heat, the crosslinking reaction is promoted, the molecular weight is increased, and a foreign matter defect tends to occur. For example, the polymer tends to stay in the Y portion rather than the X portion shown in FIG. 1, and the polymer tends to stay in the Z portion rather than the Y portion. In the polymer filter 1, since the polymer discharge port 11 </ b> C for discharging the polymer that has passed through the side of the leaf disk type filter 13 to the outside space of the polymer filter 1 is provided, the retention of the polymer can be suppressed and has remained. The polymer can be effectively removed without passing the polymer through the leaf disk filter 13 and mixing the retained polymer into the product.

  As shown in FIG. 1, in the polymer filter 1, the container body 11 has a polymer discharge port 11 </ b> C at the end on the open portion 11 b side. The polymer outlet 11C is disposed at a position where the polymer tends to stay during filtration of the polymer. Thus, it is preferable that the container body has a polymer outlet at the end on the open side. Moreover, it is preferable that the polymer discharge port is disposed at a position where the polymer tends to stay during filtration of the polymer. When the polymer is filtered by the polymer filter, the polymer tends to stay on the open portion side in the container body. By providing the polymer outlet at the end of the container main body, which is a portion that tends to stay, the foreign matter is less likely to be contained in the filtered polymer.

  Moreover, as shown in FIG. 2, in the polymer filter 1, the container main body 11 has a plurality of polymer discharge ports 11C. Here, three polymer discharge ports 11C are arranged at intervals on the lower side of the container main body 11. Thus, the container body preferably has a plurality of polymer outlets. In this case, when the polymer is filtered by the polymer filter, the polymer is more difficult to partially stay. For this reason, it becomes difficult to contain a foreign material further in the filtered polymer.

  In the polymer filter 1, the polymer outlet 11C can be opened and closed by the opening and closing member 11c. Thus, it is preferable that the polymer outlet 11C can be opened and closed. In this case, the amount of polymer discharged from the polymer outlet can be easily adjusted. For example, in the initial stage of filtering the polymer with a polymer filter, there is little or no retained polymer. On the other hand, if the time for filtering the polymer by the polymer filter becomes longer, the amount of the retained polymer tends to increase. By opening and closing the polymer outlet, it is possible to open the polymer outlet when it is difficult for the polymer to stay and foreign matter to enter, and to close the polymer outlet when the polymer is likely to stay and foreign matter is likely to enter. is there. For this reason, it can suppress discharging | emitting polymer excessively from a polymer discharge port, and can reduce the polymer amount discarded.

  The polymer filter 1 is attached to the polymer discharge port 11C and includes a discharge speed control member 17 for controlling the speed at which the polymer is discharged from the polymer discharge port 11C. Thus, the polymer filter according to the present invention is preferably attached to the polymer discharge port, and preferably includes a discharge speed control member for controlling the speed at which the polymer is discharged from the polymer discharge port. In this case, the amount of polymer discharged from the polymer outlet can be adjusted. The discharge speed control member is preferably a suction member that sucks the polymer. Since the viscosity of the staying polymer tends to be relatively high, the polymer outlet may be clogged. By providing a discharge speed control member such as a suction member, clogging of the polymer discharge port can be suppressed.

(Details of Extruder, Extruded Product Manufacturing Method, and Optical Film Manufacturing Method)
An extrusion apparatus according to the present invention includes an extruder, the polymer filter connected to the tip of the extruder, and a mold connected to the polymer filter.

  The extrusion apparatus according to the present invention is preferably an extrusion apparatus that is used to obtain an optical film by forming a polymer into a film by a melt extrusion method.

  The method for producing an extrusion-molded product according to the present invention is a method for producing an extrusion-molded product in which a polymer is molded by a melt-extrusion method, wherein the melted polymer is filtered through the polymer filter and filtered. A molding step in which the polymer is extruded from the mold and molded, and a cooling step in which the molded polymer is solidified by cooling to obtain an extruded product.

  The method for producing an optical film according to the present invention is a method for producing an optical film in which a polymer is formed by a melt extrusion method, wherein the molten polymer is filtered through the polymer filter and filtered. A film forming step of extruding a polymer from a mold to form a film, and a cooling step of solidifying the polymer formed into a film by cooling to obtain an optical film are provided.

  In FIG. 3, the schematic block diagram which shows an example of the extrusion apparatus which shape | molds a polymer with a melt extrusion method is shown.

  The extrusion apparatus 21 shown in FIG. 3 is a melt extrusion apparatus. The extrusion device 21 is an extrusion device that is used for forming a polymer by a melt extrusion method to obtain an extruded product. The extrusion device 21 is an extrusion device that is used for obtaining an optical film by forming a polymer into a film by a melt extrusion method.

  The extrusion apparatus 21 includes an extruder 22, the polymer filter 1 described above, a polymer recovery unit 23, a mold 24, a film forming roll 25, and first and second cooling rolls 26 and 27.

  The extruder 22 has a hopper 22 a for putting the polymer into the extruder 22. The polymer filter 1 is connected to the tip of the extruder 22. The polymer filter 1 is attached to the tip of the extruder 22 from the inlet 11a side of the container body 11. The polymer filter 1 is connected to the mold 24. The polymer filter 1 is attached to the mold 24 from the base plate 12 side. Below the polymer filter 1, a polymer recovery unit 23 that recovers unnecessary polymer discharged by the polymer filter 1 is disposed.

  The film forming roll 25 is a roll for cooling the polymer formed into a film. The first and second cooling rolls 26 and 27 are rolls for solidifying the film 31 (extruded product) formed (formed) by the film forming roll 25 by cooling.

  When an optical film is obtained using the extrusion device 21, the polymer is put into the extruder 22 from the hopper 22a. In the extruder 22, the polymer is heated and melted, kneaded and extruded. The polymer extruded by the extruder 22 is guided to the polymer filter 1. The polymer filtered by the polymer filter 1 is guided to the mold 24. Unnecessary polymer discharged from the polymer outlet 11 </ b> C of the polymer filter 1 is recovered by the polymer recovery unit 23.

  The polymer is extruded from the opening of the mold 24 and discharged to form a polymer into a film. The discharged film 31 is brought into contact with the film forming roll 25 and cooled. The film 31 cooled by the film forming roll 25 is further cooled by the first and second cooling rolls 26 and 27, solidified, wound up, and a roll-shaped raw film is obtained. The roll-shaped raw film is a long film.

  The distance from the opening of the mold 24 to the contact point where the film 31 contacts the film forming roll 25, that is, the air gap is preferably short. When the air gap is short, thickness variation due to disturbance can be reduced. That is, a film having an appropriate thickness profile can be stably produced. The air gap is preferably 70 mm or less.

  When the film 31 comes into contact with the film forming roll 25, it is desirable that air does not enter between the film forming roll 25 and the film 31 and that the cooling rate is uniform over the entire surface of the film 31. Therefore, it is desirable to press the film 31 to the film forming roll 25 side by pressing means such as a touch roll in the vicinity of the downstream side of the contact point between the film 31 and the film forming roll 25. The pressing means is not limited to the touch roll. As the pressing means, an air knife or electrostatic pinning may be used. A touch roll having a surface formed of an elastic material is preferably used because it is excellent in stability and the film can be uniformly pressed against the film forming roll 25.

  In addition, the polymer filtered with the said polymer filter is not specifically limited. For example, in order to obtain the optical film, a thermoplastic resin is generally used as the polymer. Examples of the thermoplastic resin include polycarbonate resins, cellulose resins, vinyl chloride resins, acrylonitrile resins, styrene resins, polyolefin resins, and polysulfone resins.

  The extrusion apparatus 21 shown in FIG. 3 is only an example of an extrusion apparatus, and the configuration of the extrusion apparatus can be changed as appropriate.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples.

Example 1
A polymer filter 1 shown in FIGS. Moreover, the extrusion apparatus 21 shown in FIG. 3 provided with the polymer filter 1 was prepared.

  Using a single screw extruder as the extruder 22, using a full flight screw with a diameter of 90 mm and L / D = 28, the melting part temperature of the extruder 22 is set to 260 ° C., and a pellet-shaped resin (polymer) is melt-extruded. Then, the gel in the molten resin was filtered using the polymer filter 1.

  The polymer filter 1 includes a polymer outlet 11C (leak hole) for discharging the deteriorated resin. As the leaf disk type filter 13, a leaf disk type filter formed of a stainless steel fiber sintered body and having a filtration accuracy of 5 μm and a diameter of 8 inches was used. 60 sheets were stacked and mounted on the center post 15 with gaskets sandwiched between the leaf disk type filters 13, and assembled into the housing 11 </ b> A of the container body 11.

  Three polymer outlets 11C for discharging the deteriorated resin were arranged in the circumferential direction at positions closest to the base plate 12 in the housing 11A. A resin tube was attached to the polymer outlet 11C (leak hole) so that the discharged resin can be easily disposed of.

  Using a stainless steel tray as the polymer recovery unit 23, the polymer recovery unit 23 recovered the resin discharged from the polymer discharge port 11C.

  An aluminum cast-type heater was used as a heating means for the polymer filter 1, and the resin was filtered at a temperature of 260 ° C.

  The molten resin obtained by filtering the polymer filter 1 was formed into a film using a die 24 which is a T die having a width of 1500 mm and a WC land sprayed on the tip of the lip land. The resin formed into a film is cooled by a film forming roll 25 having a diameter of 300 mm and the surface being HCr plating, and further cooled by the first and second cooling rolls 26 and 27, and an optical film having a thickness of 50 μm. A film was prepared.

  In addition, the resin was charged naturally by its own weight by filling the hopper 22a on the extruder 22 with pellets. Further, nitrogen was fed into the hopper 22a from the resin charging port to discharge oxygen. The temperature of the cylinder located in the measuring portion was 250 ° C., and the temperature from the cylinder to the mold 24 was set to 250 to 260 ° C.

  As the film forming roll 25, a cooling roll provided with a temperature adjusting mechanism (using oil as a heat medium) of a heat medium circulation heating system was used.

  The pre-dried and melted resin was extruded from the extruder 22 at an extrusion speed of 100 kg / h. The effective width was 1300 mm.

(Comparative Example 1)
A polymer filter configured in the same manner was used except that the polymer discharge port was not provided in the polymer filter 1 shown in FIG. An optical film having a thickness of 50 μm was obtained in the same manner as in Example 1 except that the resin was not discharged using a polymer filter having no polymer discharge port.

(Evaluation)
The optical film (raw film) obtained in Example 1 and Comparative Example 1 was continuously unwound and stretched uniaxially in the width direction at a draw ratio of 2.0 times using a tenter stretching machine. An optical film was obtained. Using this stretched optical film, point-like defects were evaluated by the following method.

<Evaluation method for point defects>
The obtained optical film was cut into a square with an area of 0.5 m ² and sandwiched between polarizing plates in a crossed Nicol state to obtain a sample. The obtained sample was placed on a work table having a desktop illuminance of 1000 lux, and the number of dotted defects derived from a gel having a size of 100 μm or more was visually counted using reflected light and transmitted light. For the optical films obtained after 30 hours, 100 hours, 200 hours, and 400 hours from the start of extrusion, the number of point defects per 10 m ² was counted.

    The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1 ... Polymer filter 11 ... Container main body 11A ... Housing 11B ... Housing lid 11C ... Polymer discharge port 11a ... Polymer inflow port 11b ... Opening part 11c ... Opening-closing member 12 ... Base plate 12a ... Through-hole 13 ... Leaf disk type filter 13a ... Inner circumference Portion 14 ... Pressure plate 14a ... Through hole 15 ... Center post 15a ... Polymer flow path 15b ... Through hole 16 ... Presser screw 17 ... Discharge rate control member 21 ... Extruding device 22 ... Extruder 22a ... Hopper 23 ... Polymer recovery part 24 ... Mold 25 ... Film forming roll 26, 27 ... First and second cooling rolls 31 ... Film

Claims (12)

A polymer filter for filtering the polymer,
A container body having a polymer inlet and an opening;
A base plate attached to the open portion of the container body;
A plurality of leaf disc filters for filtering the polymer that is disposed in the container body and flows into the container body;
The container body is not filtered by the leaf disk type filter, and polymer drainage for discharging at least a part of the polymer that has passed through the side of the leaf disk type filter in the container body to the external space of the polymer filter. A polymer filter having an outlet. A holding plate that fixes the leaf disk filter so that the plurality of leaf disk filters are in contact with each other;
The center post according to claim 1, further comprising a center post inserted into the leaf disk type filter and having a polymer flow path for allowing the polymer filtered by the leaf disk type filter to flow out to an external space of the polymer filter. Polymer filter.   The said container main body is a polymer filter of Claim 1 or 2 which has the said polymer discharge port in the edge part by the side of the said open part.   The polymer filter according to claim 1, wherein the container body has a plurality of the polymer outlets.   The polymer filter according to any one of claims 1 to 4, wherein the polymer outlet is disposed at a position where the polymer is likely to stay during filtration of the polymer.   The polymer filter according to any one of claims 1 to 5, wherein the polymer outlet is openable and closable.   The polymer filter according to any one of claims 1 to 6, further comprising a discharge speed control member that is attached to the polymer discharge port and controls a speed at which the polymer is discharged from the polymer discharge port.   The polymer filter according to any one of claims 1 to 7, which is a polymer filter for an optical film for obtaining an optical film. An extruder,
A polymer filter connected to the tip of the extruder;
A mold connected to the polymer filter,
The extrusion apparatus whose said polymer filter is a polymer filter of any one of Claims 1-8.   The extrusion apparatus according to claim 9, which is an extrusion apparatus used for obtaining an optical film by forming a polymer into a film by a melt extrusion method. A method for producing an extruded product in which a polymer is molded by a melt extrusion method,
A filtration step of filtering the molten polymer through a polymer filter;
A molding process in which the filtered polymer is extruded from a mold and molded;
A cooling step of solidifying the molded polymer by cooling to obtain an extruded product,
The manufacturing method of an extrusion molded article using the polymer filter of any one of Claims 1-8 as the said polymer filter. A method for producing an optical film in which a polymer is formed by a melt extrusion method,
A filtration step of filtering the molten polymer through a polymer filter;
A film forming step of extruding the filtered polymer from a mold and forming a film;
A cooling step of solidifying the polymer formed into a film by cooling to obtain an optical film,
The manufacturing method of an optical film using the polymer filter of any one of Claims 1-8 as the said polymer filter.

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