JP2010131912A - Filtration device, and method of manufacturing polyolefin-based resin composition using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filtration device which is capable of satisfactorily reducing foreign matters contained in molten material of a polyolefin-based resin composition and is useful for manufacturing a molded product having an excellent appearance. <P>SOLUTION: The filtration device 1 comprises a housing 10 which houses a cylindrical body 20 and has a feed path 10a and a discharge path 10b of the molten material, and a shaft 30 for attaching the cylindrical body 20 into the housing 10. The cylindrical body 20 is formed by fastening a cylindrical film support member 25 having an opening formation part 25A on which a plurality of openings 25a are formed and both end parts 25B of which outer circumferential surfaces are formed with smooth surfaces over the circumferential direction and a sintered metal filter 21 disposed on the outer circumferential surfaces of the support member 25 by using fastening members 26 on the both end parts 25B of the support member 25. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a filtration device for filtering a melt of a resin composition containing one or more polyolefin components, and a method for producing a polyolefin resin composition using the same.

  Polyolefin resin compositions are widely used as raw materials for polymer films because they are excellent in various properties such as mechanical strength, heat sealing performance, chemical resistance, and food hygiene. In recent years, this polyolefin resin composition has begun to be used for packaging of more expensive contents and for members of expensive industrial products, and the demand for quality has become stricter than before.

  If the polyolefin resin composition contains foreign substances such as gel-like polymer carbide or dust, when the polyolefin resin composition is molded into a film, the surface has a circular defect (similar to the shape of a fish eye) For this reason, it is referred to as “fish eye”), which deteriorates the appearance.

  As a method for removing foreign substances from a polyolefin resin composition, a method of filtering the composition with a metal sintered filter such as a metal mesh, a metal fiber sintered body, or a metal powder sintered body is known. In order to sufficiently suppress the generation of fish eyes, a filter having excellent filtration accuracy is usually used. However, when a higher quality is required, even if a filter with excellent filtration accuracy is used, a resin composition that satisfies the requirements may not be sufficiently obtained. Therefore, not only improving the filtration accuracy of the filter but also examining the structure of the filter itself. For example, Patent Documents 1 to 3 describe a method of performing filtration using a leaf disk type filter or a pleated filter. Patent Documents 4 and 5 describe a method of filtering a plastic material using a filtering device including a cylindrical body including a cylindrical breaker plate and a filter covering the outer periphery thereof.

On the other hand, with the diversification of products, there is an increasing demand for polyolefin-based resin compositions to achieve various physical properties and processability at a high level. In order to meet such demands, polyolefin resin compositions containing a plurality of polyolefin components have been studied. In such a polyolefin-based resin composition, there is a tendency that fish eyes are likely to be generated due to poor dispersion of each component, and therefore a method using various types of filters has been proposed (see, for example, Patent Document 6). ).
JP 2006-88081 A Japanese Patent Laid-Open No. 9-38423 International Publication No. 2003/099417 Pamphlet JP 2006-7542 A JP-A-10-44216 JP 2000-511967

  However, a filtration device equipped with a leaf disk type filter or a pleated filter has room for improvement in terms of pressure resistance, and it is difficult to sufficiently increase the pressure when filtering a polyolefin resin composition melt. It was. That is, when these filtration devices perform filtration at a filtration pressure higher than the allowable pressure of the device, the member holding the filter may not be able to withstand that pressure and may be damaged. In this case, a melt in which foreign matter is not sufficiently reduced flows downstream of the filter. If such a situation occurs, the molded product obtained from the polyolefin-based resin composition has insufficient quality in terms of appearance and the like.

  On the other hand, the filtration device provided with a cylindrical body composed of a cylindrical breaker plate and a filter covering the outer periphery thereof has room for improvement in terms of sealing performance between the breaker plate and the filter. That is, at both ends of the cylindrical body, the melt that should pass through the filter may flow between the breaker plate and the filter and be mixed downstream.

  The present invention has been made in view of such circumstances, and a filtration device that can sufficiently reduce foreign matter contained in a melt of a polyolefin resin composition and is useful for producing a molded article having an excellent appearance. And it aims at providing the manufacturing method of the polyolefin-type resin composition using the same.

  The filtration device according to the present invention is for filtering a melt of a resin composition containing one or more polyolefin components, and a plurality of openings penetrating from the outer peripheral surface to the inner peripheral surface are formed. A cylindrical filter support member having both ends formed with an opening forming portion and an outer peripheral surface that is smooth in the circumferential direction, and metal sintering with a filtration accuracy of 1 to 200 μm provided on the outer peripheral surface of the filter support member A filter, a band-like or annular fastening member that applies a pressing force to the sintered metal filter in the direction of the smooth surface on the smooth surfaces at both ends of the filter support member, and the filter support member and A cylindrical body in which a sintered metal filter is integrated is accommodated, a housing having a melt supply path and a discharge path, and the cylindrical body are placed in the housing. Is fixed, characterized in that it comprises a shaft having a channel melt flow after passing through the sintered metal filter is communicated with the discharge passage of the housing.

  In the filtration device according to the present invention, the filter support member and the sintered metal filter are integrated by the fastening member to form a cylindrical body. Since the space between the filter support member and the sintered metal filter is sufficiently sealed by using the tightening member, it is possible to sufficiently prevent the melt from leaking to the downstream side from between these. Moreover, the opening is not formed in the both ends of the filter support member by which a metal sintered filter is pressed by the clamping member, and the outer peripheral surface is a smooth surface. For this reason, even if the metal sintered filter is pressed against the filter support member by the fastening member, the deformation of the metal sintered filter can be sufficiently suppressed. On the other hand, when the opening is formed at both ends of the filter support member, the sintered metal filter pressed by the fastening member may be deformed at the opening portion, and the filtration accuracy may be reduced.

  When filtering a melt containing two or more kinds of polyolefin components, according to the filtration device of the present invention, each component contained in the melt is melted by passing through a sintered metal filter having a filtration accuracy of 1 to 100 μm. At the same time as removing foreign substances contained in the body, each component can be highly dispersed. By using a raw material composition in which each component is highly dispersed, a molded body having an excellent appearance can be produced with a sufficiently small amount of fish eyes.

  The filter support member may further include a portion to be bonded whose outer peripheral surface is a smooth surface over the axial direction. In this case, after winding the sheet-like metal sintered body on the outer peripheral surface of the filter support member, the joint of the metal sintered body located on the part to be bonded is crimped by a resin member or a metal member, It is preferable to form a sintered metal filter on the filter support member. By crimping the joint of the metal sintered body using the resin member or the metal member, it is possible to sufficiently prevent the melt from leaking to the downstream side through the joint. Moreover, by performing the crimping | compression-bonding of the joint of the metal sintered body by the resin member or the metal member on the part to be crimped, the deformation of the metal sintered body accompanying the crimping can be sufficiently suppressed, and more reliably from the joint. Can be prevented.

  The cylindrical body further includes a wire mesh having a wire diameter of 0.01 to 0.25 mm between the sintered metal filter and the filter support member, and the wire mesh is preferably in direct contact with the inner peripheral surface of the sintered metal filter. . By adopting such a configuration, it is possible to perform the filtration process of the melt with a relatively high filtration pressure. For this reason, a sufficiently high filtration rate can be achieved, and the throughput per unit time is improved. The main reason that high pressure resistance can be achieved is that the metal sintered filter has a predetermined wire diameter (0.01 to 0.25 mm) so that the sintered metal filter does not directly contact the opening forming portion of the filter support member. It is considered that even when the sintered metal filter is pressed in the direction of the filter support member due to the pressure, the deformation of the sintered metal filter at the opening is sufficiently suppressed.

  It is preferable that the shaft is detachably attached to the housing. In this case, it is preferable that the filtration device of the present invention further includes a shaft drive mechanism that moves the shaft in the longitudinal direction together with the cylindrical body and takes it out of the housing. By adopting such a configuration, there is an advantage that each constituent member of the cylindrical body can be easily replaced and cleaned.

  The method for producing a polyolefin-based resin composition according to the present invention includes a melting step of preparing a melt containing one or more polyolefin components, and a filtration step of filtering the melt in the filtration device according to the present invention. It is characterized by providing. According to the manufacturing method according to the present invention, since the filtration device having the above-described configuration is used, a melt in which the content of foreign matter is sufficiently reduced can be obtained. For this reason, it is possible to produce a polyolefin-based resin composition useful for producing a molded article having an excellent appearance.

  Moreover, when manufacturing a polyolefin-type resin composition from the melt containing 2 or more types of polyolefin components, according to the manufacturing method of this invention, each component contained in a melt in a filtration process is 1-100 micrometers of filtration precision. By passing through the sintered metal filter, foreign substances contained in the melt can be removed, and at the same time, each component can be highly dispersed. By using a raw material composition in which each component is highly dispersed, a molded body having an excellent appearance can be produced with a sufficiently small amount of fish eyes.

  ADVANTAGE OF THE INVENTION According to this invention, the foreign material contained in the melt of a polyolefin-type resin composition can fully be reduced, and the filtration apparatus useful for manufacturing the molded object of the outstanding external appearance, and the polyolefin-type resin composition using the same A manufacturing method is provided.

(Filtering device)
First, a preferred embodiment of a filtration device according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an internal configuration of the filtration device according to the present embodiment. A filtration device 1 shown in the figure is for filtering a melt of a resin composition supplied from an extruder or the like. The filtration device 1 includes a housing 10, a cylindrical body 20 that is installed in the housing 10 and performs filtration of the melt, and a shaft 30 that fixes the cylindrical body 20 in the housing 10.

  The housing 10 includes a supply path 10 a that supplies a melt of the resin composition to the outer peripheral surface side of the cylindrical body 20 and a discharge path 10 b that discharges the melt that has been filtered by the cylindrical body 20. The housing 10 has a through hole 10c that penetrates the housing 10 in the longitudinal direction, and the shaft 30 can be mounted in the through hole 10c. The shaft 30 is detachable from the housing 10, and the housing 10 includes a guide (shaft drive mechanism) 12 for moving the shaft 30 in the longitudinal direction. The cylindrical body 20 can be taken out from the housing 10 by moving the shaft 30 along the guide 12. The housing 10 preferably includes a plurality of through holes 10c for mounting the shaft 30 and includes a plurality of systems (see FIG. 5). By adopting such a configuration, even when one system cannot be used for replacement of the cylindrical body 20 or the like, the operation can be continued by using another system.

  FIG. 2A is a plan view showing the cylindrical body 20. The cylindrical body 20 is for removing foreign matters contained in the melt by the sintered metal filter 21 disposed on the outermost surface by passing the melt supplied to the outer peripheral surface side to the inner peripheral surface side. is there. In addition to this, the cylindrical body 20 also has a function of sufficiently uniformly dispersing a plurality of polyolefin components contained in the melt by the sintered metal filter 21.

  The cylindrical body 20 includes a sintered metal filter 21, a metal mesh 22 disposed so as to be in direct contact with the inner surface of the sintered metal filter 21, and a cylindrical breaker plate (filter) that supports the sintered metal filter 21 and the metal mesh 22. Support member) 25 (see FIG. 2B). The sintered metal filter 21 and the wire mesh 22 are fixed on the outer peripheral surface of the breaker plate 25 by fastening members 26 wound around both ends of the cylindrical body 20. The cylindrical body 20 is formed by winding a wire mesh 22 on the outer peripheral surface of the breaker plate 25, winding a sheet-like metal sintered body thereon, and then sealing the joint of the metal sintered body with a crimping member 28a. it can. FIG.2 (b) is a schematic cross section which shows the structure of the joint of the metal sintered compact to form. As shown in the figure, the joint of the sintered metal body is sealed by the crimping member 28a and the screw 28b.

  The fastening member 26 shown in FIG. 2 is a band-shaped member, but a ring-shaped member (for example, an O-ring or a V-ring) may be used instead. Further, as the crimping member 28a, a plate-like resin member or metal member can be used.

  FIG. 3 is a plan view showing the configuration of the breaker plate 25. As shown in FIG. 3, the breaker plate 25 includes an opening forming portion 25A in which a plurality of openings 25a penetrating from the outer peripheral surface to the inner peripheral surface is formed, and an end portion 25B in which the outer peripheral surface is formed as a smooth surface in the circumferential direction. And have. By making the outer peripheral surface of the end portion 25B a smooth surface, even if the sintered metal filter 21 is pressed against the breaker plate 25 by the fastening member 26, deformation of the sintered metal filter 21 can be sufficiently suppressed.

  In the end portion 25 </ b> B of the breaker plate 25, the width (width W <b> 1 shown in FIG. 3A) that forms the outer peripheral surface as a smooth surface may be appropriately set according to the size of the breaker plate 25 and the width of the fastening member 26. However, from the viewpoint of sufficiently ensuring the sealing performance at both ends of the cylindrical body 20, it is preferably 10 to 100 mm, and more preferably 20 to 50 mm.

  The breaker plate 25 further has a pressure-bonded portion 25C having a smooth outer peripheral surface over the axial direction. A plurality of holes 25c for fixing the above-described pressure-bonding member 28a with screws 28b are provided in the pressure-bonded portion 25C. Such a bonded part 25C is formed on the breaker plate 25, and the joint of the sintered metal body is sealed by the crimping member 28a on the bonded part 25C. Can be sufficiently suppressed, and leakage from the joint can be prevented more reliably.

  The width of the portion to be bonded 25C (the width W2 shown in FIG. 3A) may be appropriately set according to the size of the breaker plate 25 and the width of the pressure bonding member 28a, but the sealing property at the joint of the sintered metal body. Is preferably 10 to 100 mm, more preferably 20 to 50 mm, from the viewpoint of sufficiently securing the thickness.

  The breaker plate 25 is preferably a structure that hardly undergoes distortion even when subjected to filtration pressure. When the breaker plate 25 is deformed by the filtration pressure, the sintered metal filter 21 supported by the breaker plate 25 is deformed or damaged, and foreign matters are likely to leak downstream. From this viewpoint, as the material of the breaker plate 25, for example, carbon steel or the like is preferable. Examples of suitable materials other than carbon steel include special steels containing nickel, chromium, tungsten and the like. The thickness of the breaker plate 25 is preferably 10 to 100 mm from the viewpoint of ensuring sufficient strength.

  The opening 25a formed in the breaker plate 25 preferably has a diameter of 1 to 10 mm. The opening ratio of the breaker plate 25 is preferably 30 to 70%. When the breaker plate 25 having an opening ratio of less than 30% is used, if the filtration pressure is not excessively high, a sufficient amount of melt per unit time cannot be filtered, and the filtration pressure tends to be higher than the allowable pressure of the filtration device. On the other hand, when the breaker plate 25 having an opening ratio exceeding 70% is used, the amount of deformation of the breaker plate 25 tends to increase due to the filtration pressure. The opening ratio of the breaker plate 25 is preferably 35 to 60%, and more preferably 40 to 50%. Here, the “aperture ratio” means a value calculated by dividing the total area of the openings on the outer peripheral surface of the breaker plate 25 by the area of the outer peripheral surface.

  The sintered metal filter 21 is used for removing foreign substances contained in the melt and allowing the polyolefin components to disperse with each other. As the metal sintered filter 21, for example, a filter manufactured by sintering stainless steel (SUS316L) fiber can be used. In addition, the sintered metal filter 21 can use a commercially available thing, for example, can use NASRON (a brand name, Nippon Seisen Co., Ltd. product) etc. suitably.

  The sintered metal filter 21 has a filtration accuracy of 1 to 100 μm. The filtration accuracy here means the diameter of particles in which 95% of the particles are collected when a filtration test is performed based on JIS-B8356. If the filtration accuracy is less than 1 μm, a sufficient amount of melt per unit time cannot be filtered unless the filtration pressure is higher than the allowable pressure of the apparatus. On the other hand, if the filtration accuracy exceeds 100 μm, the removal of foreign matters and the dispersion of each component become insufficient, and the fish eye reduction effect becomes insufficient. The filtration accuracy of the sintered metal filter 21 is preferably 10 to 60 μm, and more preferably 20 to 40 μm.

  The wire mesh 22 is wound one or more times on the opening forming portion 25A of the breaker plate 25 and is in direct contact with the sintered metal filter 21. The wire diameter of the wire mesh 22 is preferably 0.01 to 0.25 mm. If the wire diameter of the wire mesh 22 is less than 0.01 mm, the sintered metal filter 21 is likely to be deformed or broken when the sintered metal filter 21 is pushed into the opening 25a of the breaker plate 25 by filtration pressure. On the other hand, if the wire diameter of the wire mesh 22 exceeds 0.25 mm, the wire constituting the wire mesh 22 bites into the sintered metal filter 21 during the filtration process, so that the sintered metal filter 21 is deformed and the filtration accuracy is lowered. Cheap. The wire diameter of the wire mesh 22 is preferably 0.03 to 0.23 mm, and more preferably 0.05 to 0.20 mm. Moreover, from the same viewpoint as the wire diameter of the wire mesh 22, the number of meshes of the wire mesh 22 is preferably 30 to 500 mesh, and more preferably 40 to 150 mesh. The number of meshes (mesh) of the metal mesh here means the number of meshes between 1 inch (25.4 mm).

  From the viewpoint of further reliably preventing the deformation and breakage of the sintered metal filter 21 in the opening 25a of the breaker plate 25, the wire mesh 22 is provided between the sintered metal filter 21 and the opening forming portion 25A of the breaker plate 25. It is preferable to wind 10 to 10 times. A wire mesh or the like may be further disposed between the wire mesh 22 and the opening forming portion 25A of the breaker plate 25. For example, as shown in FIG. 4, a wire mesh 23 having a wire diameter of 0.01 to 1 mm may be wound 1 to 10 times between the wire mesh 22 and the breaker plate 25. Further, in order to prevent the sintered metal filter 21 from being locally crushed when the cylindrical body 20 is installed in the housing 10, a wire mesh having a wire diameter of 0.01 to 0.25 mm is used as the outer peripheral surface of the cylindrical body 20. It may be wrapped around.

  The shaft 30 is for fixing the cylindrical body 20 in the housing 10. As shown in FIG. 1, the shaft 30 has a contact surface 30a with the end surface of the cylindrical body 20, and when the cylindrical body 20 is mounted on the shaft 30, the end surface of the cylindrical body 20 and the contact surface 30a are in contact with each other. The space is sealed. Further, the shaft 30 has a flow path 30 b communicating with the discharge path 10 b of the housing 10 in a state where the shaft 30 is inserted into the through hole 10 c of the housing 10. The melt after filtration is discharged from the filtration device 1 through the flow path 30b and the discharge path 10b.

  As described above, according to the filtering device 1, the predetermined region (the end portion 25B and the pressure-bonded portion 25C) of the outer peripheral surface of the breaker plate 25 is formed with a smooth surface. Even if it is used, it is possible to sufficiently prevent a decrease in filtration accuracy due to deformation of the sintered metal filter 21 or the like. On the other hand, as shown in FIG. 7A, the conventional breaker plate 55 has an opening 55a formed on the entire outer peripheral surface thereof, so that the metal sintered filter is formed by the fastening member 26 or the crimping member 28a. When 21 is pressed in the direction of the breaker plate 55, the sintered metal filter 21 may be deformed in the opening 55a and the filtration accuracy may be reduced. In addition, the conventional cylindrical body is usually formed by winding the filter medium 56 on the outer peripheral surface of the breaker plate 55 and then fixing it with a plurality of bands 57 as shown in FIG. The sealing property between 55 and the filter medium 56 was insufficient.

(Raw material for polyolefin resin composition)
The raw material composition used for production of the polyolefin resin composition will be described. As the raw material composition, a plurality of polyolefin components having different intrinsic viscosities can be prepared and used in combination. Alternatively, a polyolefin obtained by polymerizing an olefin component to produce a polyolefin and then continuously producing polyolefins having different intrinsic viscosities may be used. In addition, the said polyolefin contains the some polyolefin component from which intrinsic viscosity differs mutually. In this embodiment, it is preferable to use a raw material composition containing a plurality of polyolefin components having different intrinsic viscosities that are directly polymerized by multistage polymerization.

  As a method for producing a raw material composition, for example, a batch polymerization method in which polyolefin is produced in a polymerization tank (first stage) and subsequently polyolefins having different intrinsic viscosities are produced in the same polymerization tank (second stage). Is mentioned. As another production method, two or more polymerization tanks are arranged in series, and after the polyolefin is produced (first stage), the obtained polymer is transferred to the next polymerization tank. There is a continuous polymerization method for producing polyolefins having different intrinsic viscosities (second stage). In the case of the continuous polymerization method, the number of polymerization tanks used in the first stage and the second stage may be one tank or two or more tanks.

  As the polyolefin, for example, propylene homopolymer, propylene-ethylene random copolymer, propylene-ethylene-α-olefin terpolymer, propylene-α-olefin copolymer, propylene-ethylene-block copolymer, Examples thereof include high-density polyethylene, low-density polyethylene, ethylene-α-olefin copolymer, and butene-1 copolymer. Among these, a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-ethylene-α-olefin terpolymer, and a propylene-ethylene-block copolymer are difficult to gel even if thermal degradation occurs. This is preferable because it does not easily cause defects such as fish eyes.

  The α-olefin used in the propylene-α-olefin copolymer, propylene-ethylene-α-olefin terpolymer and ethylene-α-olefin copolymer is an α-olefin having 4 to 12 carbon atoms. For example, 1-butene, 2-methyl-1-propene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-ethyl-1-butene, 2 , 3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl-1 -Hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, methylethyl-1-butene, 1-octene, methyl-1-pentene, ethyl-1-hexene Cene, dimethyl-1-hexene, propyl-1-heptene, methylethyl-1-heptene, trimethyl-1-pentene, propyl-1-pentene, diethyl-1-butene, 1-nonene, 1-decene, 1-undecene , 1-dodecene and the like. Among these, 1-butene, 1-pentene, 1-hexene, and 1-octene are preferable, and 1-butene and 1-hexene are more preferable from the viewpoints of copolymerization characteristics and economy.

  When a propylene-ethylene copolymer is used as the polyolefin, the ethylene content in the copolymer is usually 0.1 to 20% by mass, preferably 0.5 to 10% by mass. When using a propylene-alpha-olefin copolymer, content of the alpha olefin in the said copolymer is 0.1-40 mass% normally, Preferably it is 1-30 mass%. When using a propylene-ethylene-α-olefin terpolymer, the ethylene content in the copolymer is usually 0.1 to 20% by mass, preferably 0.5 to 10% by mass, The α-olefin content is usually 0.1 to 40% by mass, preferably 1 to 30% by mass. When using an ethylene-α-olefin copolymer, the content of the α-olefin in the copolymer is usually from 0.1 to 30% by mass, and preferably from 1 to 20% by mass.

  Examples of the olefin polymerization method include a solvent polymerization method using an inert hydrocarbon solvent, a bulk polymerization method using a liquid monomer as a solvent, and a gas phase polymerization method performed in a gas monomer. In addition, as a method for directly obtaining a raw material composition containing a plurality of polyolefin components having different intrinsic viscosities by batch polymerization, batch-type batch polymerization method, continuous gas-phase-gas phase polymerization method, liquid phase -Gas phase polymerization method etc. are mentioned, Among these, from a viewpoint of productivity, the gas phase-gas phase polymerization method and liquid phase-gas phase polymerization method performed continuously are preferable.

  The polyolefin is, for example, a Ti-Mg-based catalyst comprising a solid catalyst component in which a Ti compound is compounded with a magnesium compound, a third component such as an organoaluminum compound and, if necessary, an electron donating compound. Can be obtained by using a catalyst system in combination with or a metallocene catalyst. More specifically, the catalyst systems described in JP-A-61-218606, JP-A-61-287904, JP-A-7-216017 and the like can be mentioned.

In this embodiment, it is preferable to use a raw material composition having a polyolefin component (A) having an intrinsic viscosity of 3 to 15 dl / g and a polyolefin component (B) having an intrinsic viscosity of 0.5 to 3 dl / g. Moreover, it is more preferable that the intrinsic viscosity ratio ([η] _A / [η] _B ) between the polyolefin component (A) and the polyolefin component ( _B ) is 1.5 to 30. As a result, it is possible to obtain a polyolefin-based resin composition that can further suppress the generation of fish eyes and the occurrence of processing defects such as sag and stripes. In addition, it is preferable that the intrinsic viscosity of the whole raw material composition is 1.0-3.0 dl / g from a viewpoint of obtaining a more uniform polyolefin-type resin composition.

  When the polyolefin component having the above intrinsic viscosity is used, the content of the polyolefin component (A) is preferably 0.05 to 70% by mass based on the total of the polyolefin components (A) and (B). More preferably, it is 5-40 mass%. On the other hand, the content of the polyolefin component (B) is preferably 30 to 99.95% by mass, and more preferably 60 to 99.5% by mass.

  In order to improve the performance of the polyolefin resin composition to be produced, the raw material composition includes antioxidants such as phenolic antioxidants and phosphorus antioxidants, neutralizers, lubricants, antistatic agents, and anti-blocking agents. You may contain additives, such as an agent, a fluororesin, and a polyethylene-type resin.

  The method for adding the additive is not particularly limited as long as a homogeneous polyolefin resin composition can be obtained. For example, the raw material composition powder and various additives are blended using a mixing device such as a Henschel mixer and then directly pelletized, or a relatively high concentration additive masterbatch is added to a high-speed machine such as a twin-screw extruder. After pelletizing using a kneading extruder, methods such as a method of blending with a raw material composition, a method of melting an additive and adding it to a raw material composition in a liquid state, etc. can be employed.

  Examples of the phenolic antioxidant include 2,6-di-t-butyl-4-methylphenol and tetrakis [methylene-3 (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate]. Methane, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) ) Propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5 · 5] undecane, tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate , Triethylene glycol-N-bis-3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate, 1,6-hexanediol bis 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propylate], 2,2-thiobis-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate ], Α-tocophenols represented by vitamin E, and the like.

  Examples of phosphorus antioxidants include tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, and bis (2,4-di-). t-butylphenyl) pentaerythritol diphosphite, bis (2,4-di-t-butyl-6-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) ) Pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl) -4,4′-diphenylenediphosnite, 2, 2'-methylenebis (4,6-di-t-butylphenyl) 2-ethylhexyl phosphite, 2,2 ' Ethylidenebis (4,6-di-t-butylphenyl) fluorophosphite, bis (2,4-di-t-butyl-6-methylphenyl) ethyl phosphite, 2- (2,4,6-tri- t-butylphenyl) -5-ethyl-5-butyl-1,3,2-oxaphosphorinane, 2,2 ′, 2 ″ -nitrilo [triethyl-tris (3,3 ′, 5,5′-tetra -T-butyl-1,1'-biphenyl-2,2'-diyl) phosphite and the like.

  Examples of the neutralizing agent include calcium stearate, magnesium stearate, hydrotalcite, calcium hydroxide and the like.

  Examples of the lubricant include higher fatty acid amides and higher fatty acid esters. Examples of the antistatic agent include glycerin esters, sorbitan acid esters, and polyethylene glycol esters of fatty acids having 8 to 22 carbon atoms. Examples of the anti-blocking agent include silica, calcium carbonate, talc and the like.

(Polyolefin resin composition production system and method for producing polyolefin resin composition)
Next, a polyolefin resin composition manufacturing system including the filtration device 1 and a method for producing a polyolefin resin composition using the same will be described.

  The production system according to the present embodiment is for producing pellets made of a polyolefin resin composition. As shown in FIG. 5, the manufacturing system 100 cools and solidifies the extruder 50 which melt-kneads two or more types of polyolefin components, and obtains a melt, the above-mentioned filtration apparatus 1, and the melt which passed through the filtration process. And a pelletizer 70 for producing pellets from the solidified product. A die 59 is disposed in the middle of the flow path 58 for transferring the melt from the filtration device 1 to the water tank 60 so that the melted strand can be supplied into the water tank 60.

  The extruder 50 has a hopper 52 for charging raw materials such as polyolefin on the inlet side of the main body 50a. The main body 50a has a flow path 50b for transferring an object to be processed, and one or a plurality of screws 54 are provided therein. The raw material composition charged into the hopper 52 is mixed while moving to the downstream side of the flow path 50b by the screw 54, and is heated by a heater (not shown) built in the main body 50a to become a melt.

  In addition, as the extruder 50, a commercially available extruder can be used, and specifically, a single screw extruder, a same direction rotation twin screw extruder, a different direction rotation twin screw extruder, etc. can be used. Examples of the co-rotating twin screw extruder include TEM (registered trademark) manufactured by Toshiba Machine Co., Ltd., TEX (registered trademark) manufactured by Nippon Steel Works, Ltd., and CMP (registered trademark). As the different-direction rotating twin-screw extruder, TEX (registered trademark) and CMP (registered trademark) manufactured by Nippon Steel Works, and FCM (registered trademark) and NCM (registered trademark) manufactured by Kobe Steel, Ltd. ) And LCM (registered trademark).

  The manufacturing method of the polyolefin-type resin composition which concerns on this embodiment is the melting process which prepares the melt containing 2 or more types of polyolefin components, the filtration process which filters a melt in the filtration apparatus 1, and the fusion | melting which passed through the filtration process A molding step of obtaining pellets from the body. Specifically, first, a raw material composition containing a plurality of polyolefin components having different intrinsic viscosities is charged into the hopper 52. The raw material composition is kneaded by rotating the screw 54 of the extruder 50, and the raw material is heated to 160 to 300 ° C to obtain a melt containing a plurality of polyolefin components (melting step).

  The melt supplied from the extruder 50 is introduced into the apparatus through the supply path 10 a of the filtration apparatus 1. And a melt is filtered with the metal sintered filter 21 (filtration process). The filtration rate when filtering the melt is preferably 1 to 150 cm / min. When the filtration rate is less than 1 cm / min, a metal sintered filter with a large area is required to ensure a sufficient amount of processing per unit time, and the equipment tends to be excessively large and equipment costs increase. . On the other hand, when the filtration rate exceeds 150 cm / min, the sintered metal filter 21 is deformed at the opening 25a of the breaker plate 25 and the filtration accuracy is likely to deteriorate. In addition to this, the filtration pressure is increased, and an excessive load tends to be generated on the filtration device 1.

  It is preferable to determine the filtration area so that the filtration speed of the melt in the filtration device 1 is 1 to 150 cm / min. In addition, from the viewpoint of achieving both high productivity and a fisheye reduction effect, the filtration rate is more preferably 10 to 100 cm / min, and further preferably 30 to 80 cm / min. Moreover, it is preferable that it is 3-35 MPa, and, as for the pressure difference of a filter apparatus inlet and outlet, it is more preferable that it is 10-30 MPa.

  The melt obtained by the filtration process is extruded from the die 59 and supplied to the water tank 60. The strand solidified in the water tank 60 is cut with a pelletizer 70 to obtain pellets made of a polyolefin resin composition.

  The pellets thus obtained are used for the production of, for example, automatic parts, home appliance parts, medical materials, OA equipment parts, building materials, sheets, various bottles and the like. From the viewpoint of fluidity when molding various parts from the pellets, the polyolefin resin composition preferably has a melt flow rate (MFR) of 0.1 to 300 g / 10 min, and 1 to 50 g / 10 min. It is more preferable that In addition, the melt flow rate here means a value measured at 230 ° C.

  According to the manufacturing system 100 including the filtering device 1 and the manufacturing method using the same, pellets made of a polyolefin resin composition from which foreign matters are sufficiently removed can be obtained. By using this pellet, the amount of fish eyes generated is sufficiently small, and a molded article having an excellent appearance can be produced. Moreover, since the filtration apparatus 1 can suppress a leak sufficiently even if the filtration pressure is set to be relatively high, a polyolefin resin composition can be efficiently produced.

  The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the case where the joint of the sintered metal body is crimped by the crimping member 28a and the screw 28b is exemplified. However, from the viewpoint of reducing leakage more reliably, the metal having no joint on the surface A sintered filter may be used. In this case, since there is no need to crimp the joint, a breaker plate in which the crimped portion 25C is not formed may be used.

  Moreover, in the said embodiment, although the case where the metal-mesh 22 which has a predetermined | prescribed wire diameter was arrange | positioned between the breaker plate 25 and the sintered metal filter 21 was illustrated as a particularly preferable aspect, the pressure conditions and metal of filtration processing were illustrated. Depending on the strength of the sintered filter 21, the sintered metal filter 21 may be disposed directly on the outer peripheral surface of the breaker plate 25 without using the wire mesh 22.

  Furthermore, in the said embodiment, although the manufacturing system for manufacturing the polyolefin resin composition containing 2 or more types of polyolefin components was illustrated, the polyolefin resin composition which consists of 1 type of polyolefin components is manufactured. The filtration device according to the present invention may be applied. In this case, the foreign material contained in the raw material can be sufficiently removed by filtering the raw material melt, and the generation of fish eyes and the like due to the foreign material can be reduced. Moreover, you may further implement the process of knead | mixing a melt after performing the filtration process of the melt of each polyolefin component.

  Moreover, in the said embodiment, although the case where the pellet which consists of polyolefin resin compositions was manufactured was illustrated, even if it manufactures the film or sheet | seat of various uses (for example, for food packaging, industrial use) instead of a pellet. Good. By using the melt obtained through the treatment in the filtration device according to the present invention, a polyolefin film or sheet having an excellent appearance can be produced.

As the film manufacturing apparatus, a combination of an inflation film manufacturing apparatus or a T-die film manufacturing apparatus and the filtration apparatus according to the present invention is suitable. For example, when manufacturing a T-die film, as shown in FIG. 6, the molten film extruded from the die 81 is cooled and solidified while being stretched to a desired thickness by a cooling roll 82 and an air chamber device 83. Thereafter, a film having a predetermined thickness is finally wound up by a winder 85. In addition, the processing conditions at the time of manufacturing a polyolefin-type film using a T-die film manufacturing apparatus are as follows.
Temperature of molten resin extruded from die lip: 180 to 300 ° C,
The cutting speed of the molten resin in the die lip: 10 to 1500 sec ⁻¹ ,
Rotating speed of cooling roll: 10 to 500 m / min,
Cooling roll temperature: 10-80 ° C,
Film thickness: 5-200 μm.

  You may give the process which extends | stretches the polyolefin-type film or sheet manufactured by said method, and may finally obtain a film or a sheet | seat. Examples of the stretching method include a method of stretching uniaxially or biaxially by a roll stretching method, a tenter stretching method, a tubular stretching method, or the like.

It is a schematic cross section which shows suitable embodiment of the filtration apparatus which concerns on this invention. It is a figure which shows an example of the cylindrical body which the filtration apparatus which concerns on this invention has. It is a top view which shows the breaker plate which the filtration apparatus which concerns on this invention has. It is a fragmentary sectional view which shows another example of the cylindrical body which the filtration apparatus which concerns on this invention has. It is a schematic block diagram which shows embodiment of a manufacturing system provided with the filtration apparatus which concerns on this invention. It is a schematic block diagram which shows other embodiment of a manufacturing system provided with the filtration apparatus which concerns on this invention. (A) is a top view which shows the conventional breaker plate, (b) is a top view which shows the conventional cylindrical body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Filtration apparatus, 10 ... Housing, 10a ... Supply path, 10b ... Discharge path, 12 ... Guide (shaft drive mechanism), 20 ... Cylindrical body, 21 ... Sintered metal filter, 25 ... Breaker plate (filter support member), 25a ... Opening of breaker plate, 25A ... Opening forming portion, 25B ... End, 25C ... Press-fit portion, 26 ... Clamping member, 28a ... Pressing member, 30 ... Shaft, 30b ... Flow path, 50 ... Extruder.

Claims (5)

A filtration device for filtering a melt of a resin composition containing one or more polyolefin components,
A cylindrical filter support member having an opening forming portion in which a plurality of openings penetrating from the outer peripheral surface to the inner peripheral surface and both end portions in which the outer peripheral surface is formed as a smooth surface in the circumferential direction;
A sintered metal filter having a filtration accuracy of 1 to 200 μm provided on the outer peripheral surface of the filter support member;
On the smooth surface of the both ends of the filter support member, a band-shaped or annular tightening member that applies a pressing force in the direction of the smooth surface to the sintered metal filter,
A housing having a cylindrical body in which the filter support member and the sintered metal filter are integrated by the clamping member, and a melt supply path and a discharge path,
A shaft having a flow path for fixing the cylindrical body in the housing and communicating with the discharge path of the housing and through which the melt after passing through the sintered metal filter flows.
A filtration apparatus comprising:   The filter support member further has a pressure-bonded portion having a smooth outer peripheral surface in the axial direction, and the metal sintered filter is obtained by winding a sheet-like metal sintered body on the outer peripheral surface of the filter support member. The filtration device according to claim 1, wherein the filter is formed by pressure bonding with a resin member or a metal member at a joint of the metal sintered body located on the pressed portion. .   The cylindrical body further includes a wire mesh having a wire diameter of 0.01 to 0.25 mm between the sintered metal filter and the filter support member, and the wire mesh is in direct contact with the sintered metal filter. The filtration device according to claim 1, wherein the filtration device is characterized.   The shaft is detachably attached to the housing, and further includes a shaft driving mechanism that moves the shaft in the longitudinal direction together with the cylindrical body and takes out the cylindrical body out of the housing. The filtering device according to any one of claims 1 to 3, wherein the filtering device is characterized.   A melting step of preparing a melt of a resin composition containing one or more polyolefin components, and a filtration step of filtering the melt in the filtration device according to any one of claims 1 to 4. A process for producing a polyolefin-based resin composition, comprising:

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