JP2011500368A - Extruder, system, and method for preparing a polymer and diluent mixture - Google Patents

Abstract

【Task】
The present invention relates to an extruder, system, and extrusion method for producing a polymer and diluent mixture. The extruder and the extrusion method can be used for producing a mixture of a polymer and a diluent, which is useful for producing a microporous film such as a battery separator film.
[Selection] Figure 1

Description

  The present disclosure generally relates to extruders, systems, and methods for producing polymer and diluent mixtures. The extruder, system, and method can be used to produce a polymer and diluent mixture that is beneficial for the production of microporous films such as battery separator films.

Polymeric materials are useful in the manufacture of a variety of films, sheets, and molded or formed parts. As is well known to those skilled in the art, plasticization refers to the softening of the polymeric material to such an extent that it will flow freely and assume any shape. In the case of crystalline polymeric materials, plasticization is synonymous with melting. For amorphous polymer materials, plasticization occurs at or near its glass transition temperature (T _g ).

  In the process of making polymer resins and other materials, extruders are commonly used for plasticizing, mixing and pumping the materials. In its simplest form, the extruder is a frame designed to be bolted to a concrete floor, a barrel attached to the frame, and, in the case of a twin screw extruder, from one end of the barrel to the other in the longitudinal direction. Includes two interconnected holes that extend. The twin screw extruder also includes two interengaging screws located in the two interconnected holes and drives to rotate the screws in the same direction (co-rotation) or in the opposite direction (mutual counter-rotation) Have means.

  Extruder screws are generally in the form of an elongated cylinder with a spiral surrounding and having one or more ridges, usually shown as flights. The flight can have a forward, backward or neutral pitch, and the pitch can be varied depending on a given application. The surface of the screw where the flight is raised is usually shown as the root of the screw. When the screw is viewed in cross-section, the path of a particular flight between one intersection of a line parallel to the screw axis and the next closest intersection of the flight with the line is a 360 ° circle. Usually defined. A flight tip extending toward the periphery of the circular cross section defines an upper lobe at the base of the screw. The space bounded by the screw root and any two flight sidewalls becomes the screw channel. Within a barrel or sleep, which can be generally described as a hole in an annular cylinder, the screw rotates about its longitudinal axis.

  The screw typically has an initial feed section that initiates the process of carrying the solid polymer material forward within the barrel of the extruder. The polymer material is fed into the extruder by a hopper that flows into the barrel and is emptied, or metered into a barrel (also referred to as a cylinder or hole) of the extruder via a feed chute or side feeder. I can do it. When transported away from the feed port by a screw, the direction of travel of the polymer material in the barrel is known as the downstream direction. In the case of polymer melt extrusion, with or without other intervening sections, a screw feed section or injection section is usually followed by a melting section where partial or total plasticization of the polymer material occurs. .

  Regardless of the presence or absence of other intervening sections, the screw melting section is usually followed by a metered feed section, which is usually plasticized through the downstream end of the extruder containing a die or other form of squeezing orifice. It has the function of pumping the converted material as an extrudate. Each section of the extruder and screw through which the polymer material travels before reaching the die is considered upstream of the die.

  For a twin screw extruder, if the flight of one screw is located in the channel of the other screw, it can be said that the two screws are intermeshing. In such a structure, the distance between the axis of each screw is less than the sum of the respective radii of the two screws as measured from the axis toward the top of the highest flight of the screw. In a pair of screws, if the flight shape and dimensions are such that the fit into the interdigitated channel does not substantially allow the passage of extrudable material between the flights, the screw is in a conjugate relationship. It can be said that In other cases, it can be said that the screws are in a non-conjugated relationship, and the degree of mutual meshing in the non-conjugated relationship can be varied substantially without limitation.

  Co-rotating screws allow large lateral movement of the polymer material from one screw to the other, even when in a conjugated relationship. Mixing is favored by this motion and is further enhanced when the screw is not in a conjugated relationship. The shape of the flight on the non-conjugated screw can be adjusted to cause the passage of polymer material from one channel to the two channels of the other screw. Alternatively, when the screws are conjugated or substantially conjugated, the predetermined flight shape can be designed to wipe one another in the interengagement region but not the barrel wall.

  In contrast to processing polymer resins in the form of a melt, the production of polymer-diluent mixtures, such as those used in the production of microporous polymer membranes, presents special requirements in extruder and process design. This is because, for the most part, it is necessary to introduce a large amount of solvent or diluent into the polymer material so that the polymer solvent used in the subsequent extrusion process is prepared. The microporous membrane is a primary battery and, for example, a lithium ion secondary battery, a lithium polymer secondary battery, a nickel-hydrogen secondary battery, a nickel-cadmium secondary battery, a nickel-zinc secondary battery, a silver-zinc secondary battery, etc. It is useful as a separator for secondary batteries. When microporous membranes are used as battery separators, particularly lithium ion battery separators, membrane performance significantly affects battery properties, productivity, and safety. Therefore, the microporous membrane should have appropriately balanced permeability, mechanical properties, dimensional stability, barrier properties, melting properties, etc. The term “well-balanced” means that the optimization of one of these properties does not result in a serious deterioration of another property.

  As is well known, it is desirable for batteries to have a relatively low shut-off temperature and a relatively high melting temperature, particularly in batteries that are exposed to high temperatures under operating conditions, in order to improve battery safety. Consistent dimensional properties such as film thickness are essential for high performance films. A high mechanical strength separator is desirable for improved battery assembly and manufacturing and improved durability. Optimization of material composition, casting and stretching conditions, heat treatment conditions, etc. has been proposed to improve the properties of microporous polyolefin membranes.

  In general, microporous polyolefin membranes consisting essentially of polyethylene (ie, they contain only polyethylene and no other species significantly) have a relatively low melting temperature. Therefore, in order to increase the melting temperature, proposals have been made to supply a microporous polyolefin membrane made from a mixed resin of polyethylene and polypropylene and a multilayer, microporous polyolefin membrane having a polyethylene layer and a propylene layer. The use of these mixed resins and the production of multilayer films with different polyolefin layers make it even more difficult to produce films with consistent dimensional characteristics such as film thickness.

  U.S. Pat. No. 5,573,332 presents a screw element for use in a screw type extruder. The screw elements are spiral and have pitches in various directions. Longitudinal mixing is obtained by screwing in the opposite direction, while transverse mixing is achieved by elongated wedges of side arcs. This lateral flow is a typical continuous shear flow, which is primarily a dispersive mixing operation. The combination of splitting the flow into various partial flows, recirculation and offset does not occur.

  U.S. Patent No. 6,062,719 proposes a co-rotating multi-screw extruder that includes two or more flight first and second meshing screws. The first screw includes first and second sections that are paired with the first and second sections of the second screw, respectively. In the first section of the first screw, the height of the first flight is lower than the height of the second flight, and in the second section of the second screw, the height of the first flight is used for the second flight and the extruder. Lower than the screw height.

  US Publication No. 2005/0013192 discloses a kneading disk having a plurality of disk elements with flight tips arranged at a helical angle E in a direction along the mainstream of the resin. A gap is formed between the flight chips of two adjacent disks. Resin is distributed and distributed without excessive increase in resin temperature due to approximately three types of flow: main flow that flows along the flight chip, reverse flow through the gap, and chip flow that flows on the flight chip. And kneaded. The reference discloses a continuous or "rotating" type screw section in that region to improve melt-shear in the "dispersed" region of the extruder. When dispensing or “stirring” is required, it is a discontinuous or “disc type” with disc elements arranged along the helical axis and the flight tips arranged in a discontinuous and helical manner parallel to the helical axis. Is used. The countercurrent polymer flow in the region between the flight tips (see, eg, FIG. 7) increases the polymer residence time and increases mixing uniformity. In conventional screw segments, the L / D value is small and multiple segments are required to obtain good dispersion. However, this is problematic and it is a lobe that is twice as long as the internal lobe that is effectively produced at the junction between the two connected segments. This suddenly changes the “pitch” of the robe flight. Furthermore, the total number of lobes is reduced by the number of joints in the section. All these effects reduce the beneficial polymer counterflow.

  Japanese Patent Application Laid-Open No. 2008-018687A discloses that a first extruder (biaxial extruder) is followed by a second extruder (single screw extruder), and polymer dissolution is filtered after each extruder, so that an undissolved polymer resin is obtained. Disclosed are methods and equipment for mixing polymer resins, wherein A gear pump is disposed between the twin screw extruder and the filter. In order to prevent temperature differences during melting, a static mixer can optionally be used at the entrance of the die.

  JP-A-2003-053821 discloses that a polyolefin solution is extruded through a twin-screw extruder, and each screw is at least one of (a) a forward screw cut screw element, (B) a reverse screw cut screw element, and (C) a collar. A method for producing a microporous film comprising 1 is disclosed. This treatment is said to be beneficial for mixing different types and molecular weights of polymers.

  Japanese Patent Application Laid-Open No. 07-216118A discloses a battery separator formed from a porous film containing polyethylene and polypropylene as essential components, each having at least two microporous layers with different polyethylene contents. The polyethylene content of one microporous layer is 0-20% by weight, the polyethylene content of the other microporous layer is 21-60% by weight, and the overall film is 2-40% by weight. Battery separators have a relatively high shutdown-starting temperature and mechanical strength. Since this is a “dry” process, the resin is combined as a polymer melt and then extruded.

  International Publication No. WO 2005/113657 discloses a microporous polyolefin membrane having conventional barrier properties, melting properties, dimensional stability, and high temperature strength. The membrane is made by using (a) a composition comprising lower molecular weight polyethylene and higher molecular weight polyethylene, and (b) a polyolefin composition comprising polypropylene. The microporous polyolefin membrane is produced by so-called “wet”, ie from a mixture of polymer and diluent. It is believed that improved mixing of the polymer and diluent results in improved microporous membrane yield and improved microporous membrane properties from the production process.

  As will be appreciated by those skilled in the art, the design requirements of the extruder screw for extruding the polymer melt are very different from those associated with polymer-diluent mixtures. Although a lot of research has been done on polymer dissolution, the research has largely failed in moving to the field of polymer-diluent mixture extrusion. Since the polymer-diluent mixture moves differently than the polymer melt, there is an expectation that the combination of extruder screw sections used to extrude the polymer melt will provide sufficient performance when extruding the polymer-diluent mixture. Otherwise, those skilled in the art will recognize. As is well understood, countercurrent flow of the solvent or diluent layer in the extruder is undesirable (generally undesirable). It is desirable that there be no significant amount of diluent (preferably not at all) during the injection phase of the extruder because the viscosity of the diluent is very low compared to the polymer and even a small amount of diluent prevents polymer blending. It is.

  Despite these advances in the art, there remains a need for an excellent extrusion system capable of producing high quality microporous polyolefin membranes and other films or sheets from polymer-diluent mixtures.

  In one aspect, an extruder for preparing a polymer and diluent mixture is provided. The extruder includes an elongate housing having an injection end, an outflow end and at least one intersecting hole disposed in the housing, at least one elongate extruder shaft disposed in the at least one intersecting hole, and A plurality of extruder screw sections positioned along the at least one elongated extruder shaft in a fixed angle relationship to each other, wherein the plurality of extruder screw sections are selected to form a plurality of extruder stages; The plurality of extruder stages includes an injection stage and a dispersion stage, and the plurality of extruder screw sections form a dispersion stage including at least one first kneading section including a plurality of kneading disks having at least one flight tip. The plurality of extrusions, each adjacent flight tip being progressively offset at an angle θ (0 ° <θ <90 °) It includes a screw division.

  In another aspect, an extruder for preparing a polymer and diluent mixture is provided. The extruder comprises an elongated housing having an inlet end, an outlet end, an extruder shaft length L and a pair of intersecting holes disposed in the housing, a pair of elongated extruder shafts having respective rotational axes, A pair of elongated extruder shafts disposed within the pair of intersecting holes and operable in at least one rotational direction, a plurality of extruder screws located along the pair of elongated extruder shafts in a fixed angle relationship to each other; A plurality of extruder screw sections selected to form a section, a plurality of extruder stages, an injection stage having a length Li of about 3% L ≦ Li ≦ about 30% L, about 10% L ≦ Ld ≦ A dispersion stage having a length Ld of about 35% L, a first mixing stage having a length Lm1 of about 5% L ≦ Lm1 ≦ about 45% L, a length Lm2 of about 0% L ≦ Lm2 ≦ about 50% L Second mixing with And a plurality of extruder stages including an outlet stage having a length Lo of about 0% L ≦ Lo ≦ about 40% L, a material inlet adjacent an injection end of an elongated barrel, and at least one of the diluents A first fluid inlet located in the dispersion stage for introducing a portion.

  In yet another aspect, a method for extruding a polymer and diluent mixture is provided. The method includes the steps of compounding the polymer at a rate of P grams per second during the extruder injection stage and directing the compounded polymer to the dispersion stage of the extruder. All or part of the diluent is introduced into the blended polymer of the dispersion stage at a rate of S1 (eg, measured in grams per second). Here, the diluent has a lower viscosity than the polymer. The diluent is then dispersed in the polymer and led to the first mixing stage. The second portion of the diluent can be introduced into the compounded polymer during the mixing stage of the extruder, if desired. In order to disperse the second portion of diluent in the combined polymer-diluent mixture, the second portion is introduced at a rate of S2 grams per second through the second fluid inlet. The position of the second fluid inlet is not critical. For example, a second portion of diluent can be introduced from the second mixing stage. If desired, for example, a third portion of diluent can be added to the mixing stage. When adding a third portion of diluent, it can be introduced into the blended polymer-diluent mixture at a rate of Sa grams per second, where the rate of introduction of the second portion of diluent is Sb grams per second; (Sa + Sb) is equal to S2. In the first mixing stage, the diluent and polymer are combined to produce a third stage product, the third stage product comprising: (i) the polymer-diluent mixture in the first phase; ii) includes a portion of the diluent in the second phase separated from the first phase, and (iii) a portion of the polymer in the third phase separated from the first and second phases. In one form, the mixing energy of the first mixing stage is greater than the mixing energy in either the injection stage or the dispersion stage.

  In yet another aspect, the present invention provides a system for producing an extrudate comprising a blended polymer and a diluent. An embodiment of the system includes a first extrusion means and a second extrusion means positioned downstream of the first extrusion means and in fluid communication with the first extrusion means. The pumping means is located downstream of the second extrusion means and is in fluid communication with the second extrusion means. Optionally, the first pumping means is a gear pump. Embodiments of the system also include a separation means for removing at least a portion of any unmixed polymer from the effluent of the second extrusion means. The separation means is generally located downstream of the second extrusion means and is in fluid communication with the second extrusion means. The mixing means is located downstream of the separating means and is in fluid communication with the separating means. The system also includes at least one die located downstream of the mixing means and in fluid communication with the mixing means. The system also includes a second pumping means optionally positioned between the first and second extrusion means. One advantageous second pumping is a gear pump.

  In the exemplary form disclosed herein, the number of kneading disks in at least one first kneading section of the dispersion stage is greater than 10, and the extruder screw section forming the dispersion stage is longer than about 4D in total length. Where D is the diameter of the extruder screw section.

  In another exemplary form disclosed herein, the number of kneading disks is greater than 10 and the first kneading disk of the kneading section adjacent to the flight chip of the last kneading disk of the at least one first kneading section. The offset angle with respect to the flight tip is selected to be equal to about 0 °.

  In another exemplary form disclosed herein, the number of kneading disks and the angle θ of the at least one first kneading section are adjacent to the flight chip of the last kneading disk of the at least one first kneading section. Adjacent kneading sections are selected so that the offset angle between the first kneading disc and the flight tip of the kneading section to be substantially equal to about 0 °.

  In yet another exemplary form disclosed herein, the number of kneading disks is such that the flight of the first kneading disk of the kneading section adjacent to the flight tip of the last kneading disk of the at least one first kneading section. The offset angle to the tip is selected to be equal to about 0 °.

  In yet another exemplary form disclosed herein, the elongated extruder shaft rotates co-rotating or rotating in the opposite direction.

  In yet another exemplary form disclosed herein, the method further includes a polymer-diluent mixture (eg, a polyolefin solution) through an extrusion die that includes a perforated die outlet that extrudes a stream of polymer solution. ) And a cooling step of the extrudate to form a cooled extrudate.

  In yet another aspect, the present invention relates to a method of producing a polymer extrudate. Embodiments of the method include mixing the polymer and diluent in a first extruder and transferring an effluent containing the combined polymer and diluent from the first extruder. The effluent from the first extruder is led to the second extruder, and the effluent is led to the first pumping means. The effluent of the first pumping means is separated into retentate and filtrate. The filtrate is mixed with the polymer and diluent to form a mixed filtrate, which is extruded through at least one die.

  Optionally, additional pumping means may be located downstream of the first extrusion means and upstream of the second extrusion means and in fluid communication with the first and second extrusion means. For example, the first extrusion means can be a twin screw extruder. For example, the second extrusion means can be a single screw extruder. For example, the first and second pumping means can each be one or more gear pumps. For example, the separating means can be a filter. For example, the mixing means can be a static mixer.

  The advantages and other advantages, features, and attributes of the disclosed extruders and methods and their advantageous applications and / or uses will be read from the following details of the invention, particularly in conjunction with the drawings attached hereto. It becomes clear.

FIG. 1 is a schematic view relating to a longitudinal side view of a twin screw extruder according to the present invention. FIG. 2 is a cross-sectional view through the extruder at line 2-2 in FIG. 1 and is a diagram of two kneading sections according to the present invention. FIG. 3 is a block diagram of a screw section used for preparing a polymer solution according to the present invention. FIG. 4A shows the kneading section of the extruder screw according to the present invention. FIG. 4B shows an end view of the kneading section of FIG. 4A according to the present invention. FIG. 5 is a block diagram of another screw segment used in the preparation of a polymer solution according to the present invention. FIG. 6 is a block diagram of yet another screw section used in the preparation of the polymer solution according to the present invention. FIG. 7 is a block diagram of yet another screw section used in the preparation of a polymer solution according to the present invention. FIG. 8 is a block diagram of another screw section used for preparing a polymer solution according to the present invention. FIG. 9 is a block diagram of still another screw section used for preparing the polymer solution according to the present invention.

Detailed Description of the Invention In one form, the invention relates to a system for producing an extrudate from a mixture comprising a polymer and a diluent. In this form, the twin screw extruder is arranged as the first extruder for mixing the polymer and diluent. A single screw extruder is located downstream of the twin screw extruder and receives the blended polymer and diluent therefrom. The first extruder is generally a twin screw extruder because it has been observed that the twin screw extruder mixes the polymer and diluent more thoroughly than the single screw extruder. The second extruder (single screw extruder) is located downstream of the first extruder (double screw extruder). This is because single screw extruders have less variation in the flow rate and flow pressure of the extruded mass compared to when a twin screw extruder extrudes a polyolefin-diluent mixture, and thus more for a more uniform extrusion product. This is because it is observed to provide a constant dice flow to the polymer-diluent mixture. In one embodiment, separation means such as, for example, one or more filters are located downstream of the first and / or second extruders and polished from the polymerized catalyst fines, unmixed polymer and process equipment. Separate and remove at least part of the metal particles and the like. One or more pumping means such as gear pumps are used to overcome the pressure drop caused to the system by the filter. Positioning the combination of pumping means (in this case a gear pump) and separation means (in this case a filter) downstream of the second extruder and upstream of the die can provide phase separation of the combined diluent and polymer. It has been observed that it can be done. A mixing means (in this case a static mixer) is used to recombine the polymer and diluent into a single phase before introducing the extrudate into the die.

  In the present invention, when a polymer and diluent (fluid) are extruded to produce a polymer and diluent mixture, the mixing screw or the screw at the injection stage of the extruder (eg, the first extruder) is “rotated”. Includes one or more screw segments (or consisting of said screw segments) having continuous flights of mold, ie, polymer “distribution” or “agitation” as defined in US Publication No. 2005/0013192 That is based in part on the desired discovery. Also, the injection stage is followed by a dispersion stage, where the mixing screw or extruder dispersion stage screw includes a “disk” mold that is used to “disperse” and shear the polymer, diluent, and polymer solution (or It is also desirable to be of the “disc” type. It has also been discovered that for good mixing of the polymer and diluent, it may be advantageous to introduce the diluent at at least two points along the extruder.

The definition “advanced flight screw section” means a continuous conveying element having a sufficient flight angle to cause flow in the direction from the injection end to the discharge end of the extruder. Suitable forward flight screw sections are available from Nippon Steel Works in Tokyo (Japan) and can include sections such as H259, H261, H262 and H265, all of which are compatible with, for example, shaft TEX65 etc. There is.

  “Advance screw section” means a screw element with a flight pitch designed to transport material to the front screw section.

  “Gear kneading section” means a screw section having a kneading disc such as a plurality of gears. Suitable gear kneading sections are available from Nippon Steel Works in Tokyo (Japan) and can include neutral gear kneading sections such as H726 and H727.

  “Kneading section” means a screw section that can be continuous or discontinuous. Examples of discontinuous kneading sections include single and double flight kneading sections having kneading discs with multiple pieces (lobes) and gear kneading sections having kneading disks such as multiple gears. The length or thickness of the kneading disc depends on the dispersion speed required for mixing and is typically in the range of a few millimeters to a few millimeters, for example 2 mm to 100 mm. The continuous kneading section can have the shape of a continuous conveying element with a 90 ° flight angle such that no flow occurs in either direction.

  “Retracting screw section” means a screw element with a pitch designed to transport back to the preceding screw section and fill the barrel section.

  “Screw configuration” means the general profile of a screw resulting from changes in the geometric properties and / or configuration of successive screw sections and ensures that they function differently according to their length.

  A “section” or “screw section” is located along a tableted or splined shaft and is an extrusion that transports, shears, pressurizes, superheats and / or converts material into a continuous solution or compact. Means screw element. The element can be transportable, non-transportable or kneaded.

  “Single flight” or “double flight kneading section” means a kneading section having a kneading disc with multiple pieces. Suitable single flight or double flight kneading sections are available from Nippon Steel, Tokyo (Japan), forward kneading sections such as H266 and H267, backward kneading sections such as H299, and neutral kneading sections such as H294 and H306. It can contain divisions.

  “Twin screw extruder” means a machine with two parallel screw shafts operating in parallel in a barrel with two holes, used for mixing and processing products such as polymer solutions.

  Reference is now made to FIGS. 1-9, where the same numbers are used to designate the same parts.

  Referring now to FIG. 1, a twin screw extruder 10 is shown. The twin screw extruder 10 is available from Nippon Steel Works in Tokyo (Japan) and can be TEX54, TEX65 model etc. for commercial use or TEX30, TEX44 etc. for small scale and laboratory use. Other polyolefin extruders can be used as will be readily appreciated by those skilled in the art. The twin screw extruder 10 includes a drive motor 12, a gear device 14 joined to the injection side thereof, and a housing 16 having an injection end 18 and an outlet end 20. As shown in FIG. 2, the housing 16 includes a pair of intersecting holes 22 disposed within the housing 16. Referring again to FIG. 1, an injection hopper 24 is provided on the housing 16 for supply of the thermoplastic material to be processed. The aforementioned parts of the extruder 10 are supported on a plurality of struts 26 located on the base 28 and joined thereto. The injection hopper 24 can be equipped with a metering device (not shown) for quantitative addition of plastic pellets or other materials to the injection hopper 24. At the end of the housing 16, a discharge port 30 for the discharge of the material processed in the extruder 10 is downstream of the injection end 18 and adjacent to the outflow end 20. At least one diluent (eg, solvent) can be introduced into the extruder at one or more locations. For example, the diluent can be introduced in the first injection tube 32 in the dispersion stage, or in the second injection tube 33 located in that position and in the second mixing stage.

  Referring again to FIG. 2, the intersecting holes 22 in the housing 16 are parallel to each other. A pair of elongated extruder shafts 34, each having a rotational axis, are disposed in a pair of intersecting holes 22 and can be operated in at least one direction of rotation by being coupled to the power take-off side of the gear unit 14. It is. Here, the gear device 14 is operated by the drive motor 12. In one form, the pair of elongated extruder shafts 34 may be square, pentagonal, hexagonal or octagonal to allow tableting of a plurality of screw sections into the pair of elongated extruder shafts 34. Or a cross-section defined by a plurality of corrugations (eg, forming a spline-like periphery).

  As described in more detail below, various screw segments are selected depending on, for example, the meshing screw segment and function, and kneading arranged sequentially along the pair of elongated extruder shafts 34. A non-rotatable fixed angle relationship is provided on the elongated extruder shaft 34, such as a disk.

  Referring now to FIG. 3, a plurality of extruder screw sections are shown, the plurality of extruder screw sections being selected to form a plurality of extruder stages. In one form, the plurality of extruder stages includes an injection stage 100, a dispersion stage 200, a first mixing stage 300, a second mixing stage 400, and an effluent stage 500. These stages are also shown for the extruder 10 in FIG. Here, each step will be described with reference to FIG.

  Multiple extruder screw sections are included in the injection stage 100. As shown in FIG. 1, the injection phase 100 begins near the first end 18 and ends with the dispersion phase 200 and is positioned to receive thermoplastic material from the injection 24 for processing. As shown in FIG. 3, in one form, the injection phase 100 includes a first forward full flight screw segment 102, a pair of second forward full flight screw segments 104, and six first full flight screw segments 104. 3 forward full flight screw sections 106 are included. In one form, the length of the first advanced full flight screw section 102 is 40.5 mm. (54 mm extruder, 0.75 × extruder screw diameter “D” is used). The length of the second forward full flight screw section 104 is 1.00D and the total length of the pair is 2.00D. The third forward full flight screw section 106 has a length of 0.75D and an overall length of 4.50D. In one form, the pitch of the third forward full flight screw section 106 is shorter than that of the pair of second forward full flight screw sections 104. In one form, the injection stage 100 has a length Li of about 10% L ≦ Li ≦ about 30% L, where L is the total length of the extruder shaft 34.

  Still referring to FIG. 3, a dispersion stage 200 is formed by a plurality of extruder screw sections. As shown in FIG. 1, the dispersion stage 200 follows the injection stage 100 and ends with the first mixing stage 300 and liquid from the first fluid inlet 32 for mixing with the thermoplastic material introduced in the injection stage 100. Located to receive diluent. As shown in FIG. 3, in one form, the dispersion stage 200 includes a pre-kneading section 202, three first kneading sections 204, and twelve second kneading sections 206. In one form, the pre-kneading section 202 has a lower ability to move material forward than that of the third forward full flight screw section 106 and the second kneading section 206. In one form, the length of the pre-kneading section 202 is 1.00D. The length of the first kneading section 204 is 1.50D, and the total length of the three first kneading sections 204 is 4.50D. The length of the second kneading section 206 is 0.50D, and the total length of the 12 second kneading sections 206 is 6.00D. In one form, the dispersion stage 200 has a length Ld of about 15% L ≦ Ld ≦ about 35% L, where L is the total length of the extruder shaft 34.

  As shown in FIG. 4A, in one form, the first kneading section 204 includes a plurality of kneading disks 208. As can be seen with reference to FIG. 4B, each adjacent flight tip of the kneading disc 208 is progressively offset by an angle θ. Here, 0 ° <θ <90 ° or the angle θ may be equal to about 45 °. In another form, the number of kneading discs is greater than 10 and the offset angle between the flight tip of the last kneading disc 208 of the at least one first kneading section and the flight tip of the first kneading disc of the adjacent kneading section. Is selected to be equal to about 0 °. In yet another form, the number and angle θ of the kneading discs 208 is between the flight tip of the last kneading disc 208 of the at least one first kneading section 204 and the flight tip of the first kneading disc of the adjacent kneading section. Are selected so that adjacent kneading sections 204 can be installed such that the offset angle is substantially equal to the angle θ.

  In one form, the pair of elongated extruder shafts 34 has a hexagonal cross section, and the offset angle θ is defined as 40 ° ≦ θ ≦ 50 °. In another form, the angle θ is equal to about 45 °. In yet another form, the number of kneading disks 208 in the first kneading section 204 is greater than fifteen. In yet another form, the number of kneading discs 208 in the first kneading section 204 is 17, and the first kneading section adjacent to the flight tip of the last double flight kneading disk 208 of the at least one first kneading section. The offset angle between the kneading disc 208 and the flight tip is equal to about 0 °. As will be appreciated, the greater the number of kneading disks 208 in the first kneading section 204, the more efficient the dispersion. Also, the thinner the disc, the more efficient the dispersion.

  Traditionally, the kneading section is specified by offset angle / number of disks / disk length / section length. In one form, the first kneading section 204 is a 45/17 / 0.09D / 1.5D forward kneading section and the second kneading section 206 is a 45/5 / 0.10D / 0.50D forward kneading section. It is a division. As will be appreciated, these kneading discs are relatively narrow and allow the polymer solution to flow around the flight tip, dividing and recombining the flow many times. By accompanying an offset angle of 40 ° ≦ θ ≦ 50 ° rather than an offset angle θ of 60 °, the forward transport capability is further increased and the reverse transport capability is further decreased.

  In the case of the dispersion stage disclosed herein, designed to prepare a polymer and diluent mixture, the discontinuous kneading section described above provides the utility of dispersion rather than the utility of distribution and agitation. The point to be interesting is. This is their usefulness when used in systems designed to prepare melt mixed polymers where continuous flight kneading sections are utilized for dispersion and discontinuous kneading sections are utilized for distribution and agitation. The opposite is true. Importantly, the discontinuous kneading section described above allows back flow of the polymer or polymer-diluent mixture, but does not allow back flow of the solvent or diluent introduced in the dispersion stage.

  Referring again to FIG. 3, a first mixing stage 300 is formed by a plurality of extruder screw sections. As shown in FIG. 1, the first mixing stage 300 follows the dispersing stage 200 and ends with the second mixing stage 400. As shown in FIG. 3, in one form, the first mixing stage 300 includes a plurality of gear kneading sections 302. In another form, the first mixing stage 300 includes seven gear kneading sections 302 that are each 1.50D long and 10.50D in length. In one form, the first mixing stage 300 has a length Lm1 of about 15% L ≦ Lm1 ≦ about 35% L, where L is the total length of the extruder shaft 34.

  In one form, each gear kneading section 302 includes a plurality of multi-tooth disks, and each multi-tooth disk includes 12 gear teeth. In another form, each gear kneading section 302 includes five multi-tooth disks.

  Still referring to FIG. 3, a second mixing stage 400 is formed by a plurality of extruder screw sections. As shown in FIG. 1, the second mixing stage 400 follows the first mixing stage 300 and ends with the outflow stage 500 and further mixes with the polymer solution formed in the dispersion stage 200 and the first mixing stage 300. , Located to receive the liquid diluent from the second fluid inlet 33. As shown in FIG. 3, in one form, the second mixing stage 400 includes a plurality of pre-kneading sections 402. In one form, four pre-kneading sections 402 each of 1.00D length and 4.00D total length are used. The second mixing stage 400 also includes a plurality of gear kneading sections 404 and a plurality of neutral kneading segments 406. In one form, the second mixing stage 400 includes three gear kneading sections 404 that are each 1.50D long and 4.50D in length. In one form, the second mixing stage 400 also includes two neutral kneading sections 406, each 0.50D long and 1.00D long. In one form, the second mixing stage 400 has a length Lm2 of about 0% L ≦ Lm2 ≦ about 30% L, where L is the total length of the extruder shaft 34.

  In one form, each gear kneading section 404 includes a plurality of multi-tooth disks, and each multi-tooth disk includes 12 gear teeth. In another form, each gear kneading section 404 includes six multi-tooth disks. In one form, each neutral kneading section 406 includes a plurality of double flight kneading disks. As is conventional, each double flight kneading disc is progressively offset at an angle of 90 °.

  Referring again to FIG. 3, an outflow stage 500 is formed by a plurality of extruder screw sections. As shown in FIG. 1, the effluent stage 500 follows the second mixing stage 400, ends at the effluent end 20, and is further positioned to allow discharge from at least one outlet 36. Optionally, recycled fluff can be introduced at the fluff feed inlet 38. As shown in FIG. 3, in one form, the outflow stage 500 includes a pair of first forward full flight screw sections 502 and second forward full flight screw sections 504. In one form, each first advanced full flight screw section 502 is 1.5D in length and 3.00D in total length. The length of the second forward full flight screw section 504 is 1.00D.

  In one form, when a recycled fluff is introduced, the outflow stage 500 further includes a second kneading stage 520. The second kneading stage 520 can include a pair of forward kneading sections 506 each having a length of 1.00D, a total length of 2.00D, and a neutral kneading stage 508 having a length of 1.00D. The second kneading stage 520 also includes a reverse kneading section 510 having a length of 0.50D. The reverse kneading section 508 includes a plurality of kneading disks. Each adjacent flight tip of the plurality of kneading disks is progressively offset at an angle θ. Here, 0 ° <θ <−90 ° or the angle θ can be equal to about −45 °. If no recycled fluff is used, a plurality of forward full flight screw sections (not shown) can be used instead of the second kneading stage 520. Here, the plurality of forward full flight screw sections have a total length of 3.50D.

  As shown in FIG. 3, following the second kneading stage 520 or following a plurality of forward full flight screw sections (not shown), the outflow stage 500 comprises a pair of third forward full flight screw sections 512 and a fourth forward. Includes a full flight screw section 514. In one form, each third forward full flight screw section 512 is equivalent to the first forward full flight screw section 502 and has a length of 1.5D and a total length of 3.00D. Similarly, the fourth forward full flight screw section 514 is equivalent to the second forward full flight screw section 504 and has a length of 1.00D. Finally, the outflow stage 500 can end with a plurality of fifth forward full flight screw sections 516, each 0.75D long and 2.25D in length. In one form, the outflow stage 500 has a length Lo of about 0% L ≦ Lo ≦ about 40% L, where L is the total length of the extruder shaft 34.

  In another form, multiple extruder screw sections are shown in FIG. The plurality of extruder screw sections are selected to form a plurality of extruder stages. In one form, the plurality of extruder stages includes an injection stage 1100, a dispersion stage 1200, a mixing stage 1300, and an effluent stage 1400. Each stage will now be described with reference to FIG.

  The injection stage 1100 is formed by a plurality of extruder screw sections. Referring generally to FIG. 1, the injection phase 1100 begins near the first end 18 and ends at the dispersion phase 1200 and is positioned to receive thermoplastic material from the inlet 24 for processing. As shown in FIG. 5, in one form, the injection phase 1100 includes one first forward full flight screw section 1102, one second forward full flight screw section 1104, and six third forward full flight screw sections 1106. including. In one form, the length of the first forward full flight screw section 1102 is 40.5 mm (when a 54 mm extruder, 0.75 × extruder screw diameter “D” is used). The length of the second forward full flight screw section 1104 is 1.00D. The third forward full flight screw section 1106 has a length of 0.75D and a total length of 4.50D. In one form, the third forward full flight screw section 1106 is shorter in pitch than the pair of second forward full flight screw sections 1104. In one form, the injection stage 1100 has a length Li of about 10% L ≦ Li ≦ about 30% L, where L is the total length of the extruder shaft 34.

  Still referring to FIG. 5, a dispersion stage 1200 is formed by a plurality of extruder screw sections. As generally shown in FIG. 1, the dispersion stage 1200 follows the injection stage 1100, ends with the first mixing stage 1300, and further mixes with the thermoplastic material introduced in the injection stage 1100. Located to receive liquid diluent from 32. As shown in FIG. 5, in one form, the dispersion stage 1200 includes a pair of pre-kneading sections 1202, eleven first forward kneading sections 1204, and two second neutral kneading sections 1206. In one form, the ability of the pre-kneading section 1202 to advance the material is lower than the third forward full flight screw section 1106 and the first kneading section 1204. In one form, the pre-kneading section 1202 has a length of 0.75D and a total length of 1.5D. The length of the first forward kneading section 1204 is 0.50D, and the total length of the eleven first forward kneading sections 1204 is 5.50D. The length of the second neutral kneading section 1206 is 0.50D, and the total length of the two second neutral kneading sections 1206 is 1.00D. In one form, the dispersion stage 1200 has a length Ld of about 15% L ≦ Ld ≦ about 20% L, where L is the total length of the extruder shaft 34.

  As described above, the kneading section is specified by the offset angle / number of disks / disk length / section length. In one form, the first forward kneading section 1204 is a 45/5 / 0.10D / 0.50D forward kneading section. As will be appreciated, these kneading discs are relatively narrow and allow the polymer solution to flow around the flight, dividing and recombining the flow many times. By accompanying an offset angle of 40 ° ≦ θ ≦ 50 ° rather than an offset angle θ of 60 °, the forward transport capability is further increased and the reverse transport capability is further decreased.

  Still referring to FIG. 5, a mixing stage 1300 is formed by a plurality of extruder screw sections. The mixing stage 1300 follows the dispersing stage 1200, ends with the effluent stage 1400, and further has a second fluid inlet (if a second fluid inlet is used) to mix with the polymer solution formed in the dispersing stage 1200. ) To receive liquid diluent from. As shown in FIG. 5, in one form, the first mixing stage 1300 includes a single full flight screw section 1302 of length 0.75D, a length of 0.50D, a pair of neutral kneading of 1.00D in length. Includes section 1304 and one reverse kneading section 1306 of length 0.50D. Following the reverse kneading section 1306 is a plurality of gear kneading sections 1308. Following the reverse kneading section 1306 are seven gear kneading sections 1308, each having a length of 1.50D and a total length of 10.50D. In one form, each gear kneading section 1308 includes a plurality of multi-tooth disks, and each multi-tooth disk includes 12 gear teeth. In another form, each gear kneading section 1308 includes five multi-tooth disks. Following the gear kneading section 1308 are a plurality of forward kneading sections 1310. In one form, eight kneading sections 1310, each 0.5D in length and 4.00D in total length, are used. In one form, the mixing stage 1300 has a length Lm of about 30% L ≦ Lm ≦ about 45% L, where L is the total length of the extruder shaft.

  As shown in FIG. 5, an outflow stage 1400 is formed by a plurality of extruder screw sections. The outflow stage 1400 follows the mixing stage 1300 and ends at the outflow end 20 (see FIG. 1) and is further positioned to allow discharge from at least one outlet 36. As shown in FIG. 5, in one form, the outflow stage 1400 includes five first forward full flight screw sections 1402, one second forward full flight screw section 1404, and a pair of third forward full flight screw sections. 1406 is included. In one form, each first forward full flight screw section 1402 is 1.5D in length and 7.50D in length. The length of the second forward full flight screw section 1404 is 1.00D. Each third forward full flight screw section has a length of 0.50D and a total length of 1.50D. In one form, the outflow stage 1400 has a length Lo of about 0% L ≦ Lo ≦ about 30% L, where L is the total length of the extruder shaft 34.

  In yet another form, multiple extruder screw segments are shown in FIG. The plurality of extruder screw sections are selected to form a plurality of extruder stages. In one form, the plurality of extruder stages includes an injection stage 2100, a dispersion stage 2200, a first mixing stage 2300, a second mixing stage 2400, and an effluent stage 2500. Each stage will now be described with reference to FIG.

  The injection stage 2100 is formed by a plurality of extruder screw sections. Referring generally to FIG. 1, the injection stage 2100 begins near the first end 18 and ends at the dispersion stage 2200 and is positioned to receive thermoplastic material from the inlet 24 for processing. As shown in FIG. 6, in one form, the injection phase 2100 includes one first forward full flight screw section 2102 and four second forward full flight screw sections 2104. In one form, the length of the first forward full flight screw section 2102 is 40.5 mm (if a 54 mm extruder, 0.75 × extruder screw diameter “D” is used). Each of the second forward full flight screw sections 2104 has a length of 0.75D and an overall length of 3.00D. In one form, the injection stage 2100 has a length Li of about 5% L ≦ Li ≦ about 30% L, where L is the total length of the extruder shaft 34.

  Still referring to FIG. 6, a dispersion stage 2200 is formed by a plurality of extruder screw sections. The dispersion stage 2200 follows the injection stage 2100 and ends with the first mixing stage 2300 and further receives a liquid diluent from the first fluid inlet 32 to mix with the thermoplastic material introduced in the injection stage 2100. Is located. As shown in FIG. 6, in one form, the dispersion stage 2200 includes one color section 2202, eleven first forward kneading sections 2204, one gear kneading section 2206, and two second neutral kneading sections 2208. Including. In one form, the length of the color segment 2202 is 0.75D. The length of the first forward kneading section 2204 is 0.50D, and the total length of the eleven first forward kneading sections 2204 is 5.50D. The length of the gear kneading section 2206 is 1.50D. The length of the second neutral kneading section 2206 is 0.50D, and the total length of the two second neutral kneading sections 2206 is 1.00D. In one form, the dispersion stage 2200 has a length Ld of about 10% L ≦ Ld ≦ about 35% L, where L is the total length of the extruder shaft 34.

  As described above, the kneading section is specified by the offset angle / number of disks / disk length / section length. In one form, the first forward kneading section 2204 is a 45/5 / 0.10D / 0.50D forward kneading section. As will be appreciated, these kneading discs are relatively narrow and allow the polymer solution to flow around the flight, dividing and recombining the flow many times. By accompanying an offset angle of 40 ° ≦ θ ≦ 50 ° rather than an offset angle θ of 60 °, the forward transport capability is further increased and the reverse transport capability is further decreased.

  Still referring to FIG. 6, a first mixing stage 2300 is formed by a plurality of extruder screw sections. The first mixing stage 2300 follows the dispersing stage 2200, ends with the second mixing stage 2400, and further uses a second fluid inlet (the second fluid inlet is used to mix with the polymer solution formed in the dispersing stage 2200. Position to receive liquid diluent from As shown in FIG. 6, in one form, the first mixing stage 2300 includes one full flight screw section 2302 that is 0.75D long, one forward kneading section 2304 that is 0.50D long, and a plurality of gears. A kneading section 2306 is included. In another form, the first mixing stage 2300 includes six gear kneading sections 2306, each of 1.50D length and 9.00D total length. In one form, the first mixing stage 2300 has a length Lm1 of about 15% L ≦ Lm1 ≦ about 35% L, where L is the total length of the extruder shaft. In one form, each gear kneading section 2306 includes a plurality of multi-tooth disks, and each multi-tooth disk includes 12 gear teeth. In another form, each gear kneading section 2306 includes five multi-tooth disks.

  Still referring to FIG. 6, a second mixing stage 2400 is formed by a plurality of extruder screw sections. The second mixing stage 2400 follows the first mixing stage 2300 and ends with the outflow stage 2500. As shown in FIG. 6, in one form, the second mixing stage 2400 includes a plurality of neutral gear kneading sections 2402. In one form, seven neutral gear kneading sections 2402 are used, each 1.5D long and 10.50D long. Following the plurality of neutral gear kneading sections 2402 are three neutral kneading sections 2404, each 0.50D long and 1.50D long. Following the neutral kneading section 2404 is one reverse kneading section 2406 of length 0.50D. In one form, the second mixing stage 2400 has a length Lm2 of about 0% L ≦ Lm2 ≦ about 35% L, where L is the total length of the extruder shaft.

  As shown in FIG. 6, an outflow stage 2500 is formed by a plurality of extruder screw sections. As shown generally in FIG. 1, the effluent stage 2500 follows the second mixing stage 2400, ends at the effluent end 20, and is further positioned to allow discharge from at least one outlet 36. As shown in FIG. 6, in one form, the outflow phase 2500 includes three first forward full flight screw sections 2502, one second forward full flight screw section 2504, and one third forward full flight screw section 2506. including. In one form, each first forward full flight screw section 2502 is 1.5D in length and 4.50D in total length. The length of the second forward full flight screw section 2504 is 1.00D and the length of the third forward full flight screw section 2506 is 0.75D. In one form, the effluent stage 2500 has a length Lo of about 0% L ≦ Lo ≦ about 20% L, where L is the total length of the extruder shaft.

  In yet another form, multiple extruder screw segments are shown in FIG. The plurality of extruder screw sections are selected to form a plurality of extruder stages. In one form, the plurality of extruder stages includes an injection stage 3100, a dispersion stage 3200, a first mixing stage 3300, a second mixing stage 3400, and an effluent stage 3500. Each stage will now be described with reference to FIG.

  The injection stage 3100 is formed by a plurality of extruder screw sections. Referring generally to FIG. 1, the injection stage 3100 begins near the first end 18 and ends at the dispersion stage 3200 and is positioned to receive thermoplastic material from the inlet 24 for processing. As shown in FIG. 7, in one form, the injection phase 3100 includes one first forward full flight screw section 3102 and three second forward full flight screw sections 3104. In one form, the length of the first forward full flight screw section 3102 is 40.5 mm (if a 54 mm extruder, 0.75 × extruder screw diameter “D” is used). Each of the second forward full flight screw sections 3104 has a length of 0.75D and an overall length of 2.25D. In one form, the injection stage 3100 has a length Li of about 3% L ≦ Li ≦ about 25% L, where L is the total length of the extruder shaft.

  Still referring to FIG. 7, a dispersion stage 3200 is formed by a plurality of extruder screw sections. The dispersion stage 3200 follows the injection stage 3100 and ends with the first mixing stage 3300 and further receives a liquid diluent from the first fluid inlet 32 to mix with the thermoplastic material introduced in the injection stage 3100. Is located. As shown in FIG. 7, in one form, the dispersion stage 3200 includes three gear kneading sections 3202, six first forward kneading sections 3204, and one neutral gear kneading section 3206. In one form, each gear kneading section 3202 has a length of 1.50D and a total length of 4.50D. The length of each first forward kneading section 3204 is 0.50D, and the total length of the six first forward kneading sections 3204 is 3.00D. The length of the neutral gear kneading section 3206 is 1.50D. In one form, the dispersion stage 3200 has a length Ld of about 15% L ≦ Ld ≦ about 30% L, where L is the total length of the extruder shaft.

  As described above, the kneading section is specified by the offset angle / number of disks / disk length / section length. In one form, the first forward kneading section 3204 is a 45/5 / 0.10D / 0.50D forward kneading section. As will be appreciated, these kneading discs are relatively narrow and allow the polymer solution to flow around the flight, dividing and recombining the flow many times. By accompanying an offset angle of 40 ° ≦ θ ≦ 50 ° rather than an offset angle θ of 60 °, the forward transport capability is further increased and the reverse transport capability is further decreased.

  Still referring to FIG. 7, a first mixing stage 3300 is formed by a plurality of extruder screw sections. The first mixing stage 3300 follows the dispersing stage 3200, ends with the second mixing stage 3400, and further includes a second fluid inlet 33 (the second fluid inlet is connected to the polymer solution formed in the dispersing stage 3200). Position to receive liquid diluent from (if used). As shown in FIG. 7, in one form, the first mixing stage 3300 includes a full flight screw section 3302, length 0.75D, a neutral gear kneading section 3304, a plurality of forward gear kneading sections 3306, and A plurality of neutral gear kneading sections 3308 are included. In another form, the first mixing stage 3300 comprises five forward gear kneading sections 3306 each having a length of 1.50D and a total length of 6.00D and five each having a length of 1.50D and a total length of 7.50D. Includes neutral gear kneading section 3308. In one form, the first mixing stage 3300 has a length Lm1 of about 25% L ≦ Lm1 ≦ about 45% L, where L is the total length of the extruder shaft.

  Still referring to FIG. 7, a second mixing stage 3400 is formed by a plurality of extruder screw sections. The second mixing stage 3400 follows the first mixing stage 3300 and ends with the outflow stage 3500. As shown in FIG. 7, in one form, the second mixing stage 3400 includes eleven neutral kneading sections 3402, each 0.50D long and 5.50D long. Following the neutral kneading section 3402 are five reverse kneading sections 3404, each 0.50D long and 2.50D long. In one form, the second mixing stage 3400 has a length Lm2 of about 0% L ≦ Lm2 ≦ about 25% L, where L is the total length of the extruder shaft.

  As shown in FIG. 7, an outflow stage 3500 is formed by a plurality of extruder screw segments. As generally shown in FIG. 1, the effluent stage 3500 is located following the second mixing stage 3400, ends at the effluent end 20, and further allows for discharge from at least one outlet 36. As shown in FIG. 7, in one form, the outflow stage 3500 includes three first forward full flight screw sections 3502, one second forward full flight screw section 3504, and one third forward full flight screw section 3506. including. In one form, each first forward full flight screw section 3502 is 1.5D in length and 4.50D in total length. The length of the second forward full flight screw section 3504 is 1.00D and the length of the third forward full flight screw section 3506 is 0.75D. In one form, the outflow stage 3500 has a length Lo of about 0% L ≦ Lo ≦ about 20% L, where L is the total length of the extruder shaft 34.

  In yet another form, multiple extruder screw segments are shown in FIG. The plurality of extruder screw sections are selected to form a plurality of extruder stages. In one form, the plurality of extruder stages includes an injection stage 4100, a dispersion stage 4200, a first mixing stage 4300, a second mixing stage 4400, and an effluent stage 4500. Each stage will now be described with reference to FIG.

  The injection stage 4100 is formed by a plurality of extruder screw sections. Referring generally to FIG. 1, the injection phase 4100 begins near the first end 18 and ends at the dispersion phase 4200 and is further positioned to receive thermoplastic material from the inlet 24 for processing. As shown in FIG. 8, in one form, the injection phase 4100 includes one first forward full flight screw section 4102 and four second forward full flight screw sections 4104. In one form, the length of the first forward full flight screw section 4102 is 40.5 mm (when a 54 mm extruder, 0.75 × extruder screw diameter “D” is used). Each of the second forward full flight screw sections 4104 has a length of 0.75D and an overall length of 3.00D. In one form, the injection stage 4100 has a length Li of about 5% L ≦ Li ≦ about 30% L, where L is the total length of the extruder shaft.

  Still referring to FIG. 8, a dispersion stage 4200 is formed by a plurality of extruder screw sections. The dispersion stage 4200 follows the injection stage 4100 and ends with the first mixing stage 4300 and further receives a liquid diluent from the first fluid inlet 32 to mix with the thermoplastic material introduced in the injection stage 4100. Is located. As shown in FIG. 8, in one form, the dispersion stage 4200 includes one color section 4202 and twelve first forward kneading sections 4204. In one form, the length of the color section 4202 is 0.75D. The length of each first forward kneading section 4204 is 0.50D, and the total length of twelve first forward kneading sections 4204 is 6.00D. In one form, the dispersion stage 4200 has a length Ld of about 10% L ≦ Ld ≦ about 35% L, where L is the total length of the extruder shaft 34.

  As described above, the kneading section is specified by the offset angle / number of disks / disk length / section length. In one form, the first forward kneading section 4204 is a 45/5 / 0.10D / 0.50D forward kneading section. As will be appreciated, these kneading discs are relatively narrow and allow the polymer solution to flow around the flight, dividing and recombining the flow many times. By accompanying an offset angle of 40 ° ≦ θ ≦ 50 ° rather than an offset angle θ of 60 °, the forward transport capability is further increased and the reverse transport capability is further decreased.

  Still referring to FIG. 8, a first mixing stage 4300 is formed by a plurality of extruder screw sections. The first mixing stage 4300 follows the dispersion stage 4200 and ends with the second mixing stage 4400. As shown in FIG. 8, in one form, the first mixing stage 4300 includes a plurality of forward gear kneading sections 4302. In another form, the first mixing stage 4300 includes four forward gear kneading sections 4302 each of 1.50D length and 6.00D total length. In one form, the first mixing stage 4300 has a length Lm1 of about 5% L ≦ Lm1 ≦ about 35% L, where L is the total length of the extruder shaft.

  Still referring to FIG. 8, a second mixing stage 4400 is formed by a plurality of extruder screw sections. The second mixing stage 4400 follows the first mixing stage 4300 and ends with the outflow stage 4500 and further from the second fluid inlet 33 (if a second fluid inlet is used) to mix with the polymer solution. Located to receive liquid diluent. As shown in FIG. 8, in one form, the second mixing stage 4400 includes one full flight screw section 4402, one neutral gear kneading section 4404 of length 1.50D, each of 1.50D length, total length. 3 forward gear kneading sections 4406 of 4.50D, each of 1.50D length, 6 neutral gear kneading sections 4408 of total length 9.00D, and each of 0.50D length, 3.50D of total length Seven neutral kneading sections 4410 are included. In one form, the second mixing stage 4400 has a length Lm2 of about 0% L ≦ Lm2 ≦ about 50% L, where L is the total length of the extruder shaft.

  As shown in FIG. 8, an outflow stage 4500 is formed by a plurality of extruder screw sections. As shown generally in FIG. 1, the effluent stage 4500 is located following the second mixing stage 4400, ends at the effluent end 20, and further permits discharge from at least one outlet 36. As shown in FIG. 8, in one form, the outflow phase 4500 includes three first forward full flight screw sections 4502, one second forward full flight screw section 4504, and one third forward full flight screw section 4506. including. In one form, each first forward full flight screw section 4502 is 1.5D in length and 4.50D in total length. The length of the second forward full flight screw section 4504 is 1.00D and the length of the third forward full flight screw section 4506 is 0.75D. In one form, the outflow stage 4500 has a length Lo of about 0% L ≦ Lo ≦ about 20% L, where L is the total length of the extruder shaft.

  In another form, multiple extruder screw sections are shown in FIG. The plurality of extruder screw sections are selected to form a plurality of extruder stages. In one form, the plurality of extruder stages includes an injection stage 5100, a dispersion stage 5200, a first mixing stage 5300, a second mixing stage 5400, and an effluent stage 5500. Each stage will now be described with reference to FIG.

  The injection stage 5100 is formed by a plurality of extruder screw sections. Referring generally to FIG. 1, the injection stage 5100 begins near the first end 18 and ends at the dispersion stage 5200 and is further positioned to receive thermoplastic material from the inlet 24 for processing. As shown in FIG. 9, in one form, the injection phase 5100 includes one first forward full flight screw section 5102 and four second forward full flight screw sections 5104. In one form, the length of the first forward full flight screw section 5102 is 40.5 mm (if a 54 mm extruder, 0.75 × extruder screw diameter “D” is used). Each of the second forward full flight screw sections 5104 has a length of 0.75D and an overall length of 2.25D. In one form, the injection stage 5100 has a length Li of about 5% L ≦ Li ≦ about 30% L, where L is the total length of the extruder shaft.

  Still referring to FIG. 9, a dispersion stage 5200 is formed by a plurality of extruder screw sections. The dispersion stage 5200 follows the injection stage 5100 and ends with the first mixing stage 5300 and further receives a liquid diluent from the first fluid inlet 32 to mix with the thermoplastic material introduced in the injection stage 5100. Is located. As shown in FIG. 9, in one form, the dispersion stage 5200 includes one color section 5202 and twelve first forward kneading sections 5204. In one form, the length of the color section 5202 is 0.75D. The length of each first forward kneading section 5204 is 0.50D, and the total length of twelve first forward kneading sections 5204 is 6.00D. In one form, the dispersion stage 5200 has a length Ld of about 10% L ≦ Ld ≦ about 35% L, where L is the total length of the extruder shaft.

  As described above, the kneading section is specified by the offset angle / number of disks / disk length / section length. In one form, the first forward kneading section 5204 is a 45/5 / 0.10D / 0.50D forward kneading section. As will be appreciated, these kneading discs are relatively narrow and allow the polymer solution to flow around the flight, dividing and recombining the flow many times. By accompanying an offset angle of 40 ° ≦ θ ≦ 50 ° rather than an offset angle θ of 60 °, the forward transport capability is further increased and the reverse transport capability is further decreased.

  Still referring to FIG. 9, a first mixing stage 5300 is formed by a plurality of extruder screw sections. The first mixing stage 5300 follows the dispersion stage 5200 and ends with the second mixing stage 5400. As shown in FIG. 9, in one form, the first mixing stage 5300 includes a plurality of forward gear kneading sections 5302. In another form, the first mixing stage 5300 includes six forward gear kneading sections 5302, each of 1.50D length and 9.00D total length. In one form, the first mixing stage 5300 has a length Lm1 of about 10% L ≦ Lm1 ≦ about 35% L, where L is the total length of the extruder shaft.

  Still referring to FIG. 9, a second mixing stage 5400 is formed by a plurality of extruder screw sections. The second mixing stage 5400 follows the first mixing stage 5300 and ends with the outflow stage 5500 and further from the second fluid inlet 33 (if a second fluid inlet is used) to mix with the polymer solution. Located to receive liquid diluent. As shown in FIG. 9, in one form, the second mixing stage 5400 includes one full flight screw section 5402, one neutral gear kneading section 5404 with a length of 1.50D, and one advance with a length of 1.50D. It includes a gear kneading section 5406 and six neutral gear kneading sections 5408 each of 1.50D in length and 9.00D in total length. In one form, the second mixing stage 5400 has a length Lm2 of about 0% L ≦ Lm2 ≦ about 35% L, where L is the total length of the extruder shaft.

  As shown in FIG. 9, an outflow stage 5500 is formed by a plurality of extruder screw sections. As shown generally in FIG. 1, the effluent stage 5500 is located following the second mixing stage 5400, ending at the effluent end 20, and further allowing for discharge from at least one outlet 36. As shown in FIG. 9, in one form, the outflow stage 5500 comprises seven neutral kneading sections 5502, three first forward full flight screw sections 5504, 1 each having a length of 0.50D and a total length of 3.50D. One second forward full flight screw section 5506 and one third forward full flight screw section 5508 are included. In one form, each first forward full flight screw section 5504 has a length of 1.5D and a total length of 4.50D. The length of the second forward full flight screw section 5506 is 1.00D and the length of the third forward full flight screw section 5508 is 0.75D. In one form, the outflow stage 5500 has a length Lo of about 0% L ≦ Lo ≦ about 30% L, where L is the total length of the extruder shaft 34.

  In another form, a method for extruding a polymer and diluent mixture is provided. The method includes the steps of compounding the polymer at the injection stage 100 of an extruder (eg, twin screw extruder, etc.) at a rate of P (eg, measured as grams per second, etc.) and the compounded polymer. To the dispersion stage 200 of the extruder. Using a diluent having a lower viscosity than the polymer, at least one diluent is introduced into the polymer formulated in the dispersion stage 200 at a rate of S1 (eg, measured as grams per second, etc.). The The diluent is then dispersed in the polymer and directed to the first mixing stage 300. In one form, the diluent is introduced into the blended polymer at a rate of S2 downstream of the dispersion stage, eg, at a location such as the first mixing stage 300 and / or the second mixing stage 400. In the first mixing stage 300, the diluent and polymer are blended to produce a third stage product. The third stage product comprises (i) a first phase polymer-diluent mixture, (ii) a portion of the second phase diluent separated from the first phase, and (iii) first and second phases. Contains a portion of the third phase polymer separated from the phase. In one form, the mixing energy of the first mixing stage 300 is greater than the mixing energy of the injection stage 100 and / or the dispersion stage 200.

  In one form, the first phase is produced at a rate of R of about 0.9 × (P + S) or higher (eg, measured as grams per second, etc.). Here, S is equal to S1 + S2, the second phase is produced at a rate not exceeding 0.05 × S1, and the third phase is produced at a rate not exceeding 0.05 × P. In another form, the rate of diluent counterflow from the dispersion stage to the injection stage 100 does not exceed 0.1 × S1. Relative amounts of S, S1 and S2 are selected to prevent polymer degradation in the extruder and to prevent diluent countercurrent (downstream to upstream). In one form, the value of S1 / S2 ranges from about 51 wt% / 49 wt% to about 99 wt% / 1 wt%, preferably about 55 wt% / 45 wt%, based on the total weight of S1 + S2. To about 95% / 5% by weight, more preferably about 60% / 40% to about 90% / 10% by weight. In one form, the diluent S1 is injected into the extruder from the first fluid inlet at the dispersion stage, and the position of the first fluid inlet is within a length of about 50% Ld from the beginning of the dispersion stage, Preferably, it is located within a length range of about 30% Ld. In one form, the diluent S2 is injected into the extruder from the second fluid inlet in the mixing stage, and the location of the second fluid inlet is at the first mixing stage and / or the second mixing stage, preferably the first Located in two mixing stages. When the diluent is injected at two points in the mixing stage, the diluent can be introduced in each of the first mixing stage and the second mixing stage. By controlling the relative values of S, S1, and S2 and the appropriate choice of diluent injection position as described herein, the yield from the extruder is higher and the output mass flow rate is more stable. In one form, the extruder is at a rate of 1 kg / hour or more, eg, 20 kg / hour or more or 50 kg / hour or more, such as in the range of about 1 kg / hour to 100 kg / hour or 20 kg / hour to 75 kg / hour. Alternatively, a polymer-diluent mixture is produced at a rate such as 100 kg / hr or higher.

In another form, the majority of the polymer has a first polyethylene having a molecular weight in the range of 1.0 × 10 ⁴ to 9 × 10 ⁵ and a molecular weight in the range of 9.0 × 10 ⁵ to 5.0 × 10 ^6. It is the 2nd polyethylene which has. In yet another form, the polymer further comprises polypropylene having a molecular weight in the range of 3.0 × 10 ⁵ to 3.0 × 10 ⁶ . In one form, the first polyethylene is present in an amount of polymer in the range of 0 to 100%, the second polyethylene is present in an amount of polymer in the range of 0 to 100%, and the polypropylene is in the range of 0 to 70%. Present in a range of amounts of polymer. In another form, the diluent is liquid paraffin, P is 3 to 20, and S is 5 to 50.

In one form, the mixing energy of the injection stage 100 and the dispersion stage 200 is lower than the first mixing stage 300. The process conditions of the injection stage 100 are characterized by a temperature of 150 ° C., P = 10, a pressure of less than 5 kg / cm ² and a residence time of about 18 seconds, and the dispersion stage 200 has a temperature of 200 ° C. Characterized by a pressure of less than 5 kg / cm ² and a residence time of about 14 seconds. In another form, the mixing energy is obtained from at least one segmented mixing screw that extends continuously in the direction of polymer flow through the injection stage 100 and the dispersion stage 200.

  The form of the extruder, system, and method described herein is utilized in the extrusion and production of microporous films and microporous sheets. Single and multilayer microporous films and microporous sheets are within the scope of the present invention. These microporous films and microporous sheets are particularly utilized in the critical magnetic field of battery separators. The multilayer film and multilayer sheet described later in this specification use either a coextrusion die or a single layer die for the production of a single layer film or a single layer sheet, and further laminate an additional layer thereon by a conventional method. Can be produced.

  In one form, the multilayer, microporous polyolefin membrane comprises two layers. The first layer (eg skin, top layer or top layer of the membrane) comprises the material of the first microporous layer and the second layer (eg bottom layer or bottom layer or core layer of the membrane) is the second microporous layer. Including material. For example, when viewed from an axis approximately perpendicular to the transverse and longitudinal (flow) directions of the membrane, the membrane can have a planar top layer, where the bottom planar layer is from the view by the top layer. hide.

  In another form, the multilayer, microporous polyolefin membrane comprises three or more layers. Here, the outer layer (also referred to as “surface” or “skin” layer) comprises the material of the first microporous layer, and at least one core layer or intermediate layer comprises the material of the second microporous layer. In a related form, when the multilayer, microporous polyolefin membrane comprises two layers, the first layer consists essentially of the material of the first microporous layer and the second layer consists essentially of the material of the second microporous layer. It becomes. In a related embodiment, when the multilayer, microporous polyolefin membrane comprises more than two layers, the outer layer consists essentially of the material of the first microporous layer and at least one intermediate layer consists essentially of the material of the second microporous layer Consists of (or consists of) the above materials. In one embodiment, the microporous membrane produced by the method is about 3 to about 200 μm, or about 5 to about 50 μm, or about 7 to about 35 μm thick. The microporous membrane produced by the method according to the present invention includes primary batteries and secondary batteries, in particular, lithium ion secondary batteries, lithium-polymer secondary batteries, nickel-hydrogen secondary batteries, nickel-cadmium secondary batteries. It can be used as a battery separator such as a battery, a nickel-zinc secondary battery, a silver-zinc secondary battery, particularly a lithium ion secondary battery.

The starting materials utilized in the production of the aforementioned films and sheets are now described. As will be appreciated by those skilled in the art, the choice of starting material is not critical. Polymers and blends of polymers can be used, such as polyolefins and blends of polyolefins. Polymers, methods, and process conditions described in International Patent Publication Nos. WO 2008/016174, US Patent Publication Nos. US 2008/0057388 and US 2008/0057389, which are incorporated herein by reference in their entirety, are suitable for the present invention. In one form, the material of the first and second microporous layers comprises polyethylene. In one form, the material of the first microporous layer is a first polyethylene having a Mw value less than about 1 × 10 ⁶ (“PE-1”) or a second polyethylene having a Mw value of at least about 1 × 10 ^6. ("UHMWPE-1"). In one form, the material of the first microporous layer can include first polypropylene (“PP-1”). In one form, the material of the first microporous layer is (i) a polyolefin such as polyethylene and / or polypropylene, (ii) ultra high molecular weight polyethylene (UHMWPE), (iii) PE-1 and PP-1, or ( iv) Including any of PE-1, UHMWPE-1, and PP-1.

In one form of (ii) and (iv) above, preferred UHMWPE-1 is from about 1 × 10 ⁶ to about 15 × 10 ⁶ or about 1 × 10 ⁶ to about 5 × 10 ⁶ or about 1 × 10 ^6. In order to obtain a microporous layer having a Mw in the range of about 3 × 10 ⁶ , and more preferably having a hybrid structure as defined in the later section, about 1 weight based on the total amount of PE-1 and UHMWPE-1 %, Or about 15% to 40% by weight, and can be at least one homopolymer or copolymer. In one form of (iii) and (iv) above, PP-1 can be at least one homopolymer or copolymer, or preferably based on the total amount of microporous material in the first layer. About 25% by weight or less. In one form, the Mw of the polyolefin in the material of the first microporous layer is less than about 1 × 10 ⁶ or about 1 × 10 ⁵ to about 1 to obtain a microporous layer having a hybrid structure as defined in a later section. It can have 1 × 10 ⁶ or in the range of about 2 × 10 ⁵ to about 1 × 10 ⁶ . In one form, preferred PE-1 can have a Mw in the range of about 1 × 10 ⁴ to about 9 × 10 ⁵ or about 2 × 10 ⁵ to about 8 × 10 ⁵ , and more It can be a density polyethylene, a medium density polyethylene, a branched low density polyethylene, or a linear low density polyethylene, and can also be at least one homopolymer or copolymer.

  In one form, the material of the first microporous layer (the first of the two layers, the microporous polyolefin film and the first and third layers of the three microporous polyolefin film) is from 0.01 μm to 0.001 μm. A relatively high density domain with a main peak in the range of 08 μm and at least one sub-peak in the range of greater than 0.08 μm to 1.5 μm or a relatively low density domain indicating a small pore size distribution curve. It is a hybrid structure characterized by pore size distribution. The ratio of the pore volume of the high density domain (calculated from the main peak) to the pore volume of the low density domain (calculated from the sub-peak) is not critical, for example, ranges from about 0.5 to about 49 I can do it.

In one form, the material of the second microporous layer comprises the same material used to produce the material of the first microporous layer, such as, for example, polyethylene and / or polypropylene, optionally in different relative amounts. For example, the material of the second microporous layer can be (i) a fourth polyethylene having a Mw value of at least about 1 × 10 ⁶ (“UHMWPE-2”), (ii) a second having a Mw value less than 1 × 10 ⁶ . 3 polyethylene and UHMWPE-2 and 4th polyethylene (eg, 4th polyethylene is present in an amount of at least about 8% by weight based on the combined weight of 3rd and 4th polyethylene), (iii) UHMWPE -2 and PP-2, or (iv) PE-2, UHMWPE-2, and PP-2. In one form of (ii), (iii) and (iv) above, UHMWPE-2 produces a relatively strong, multi-layer, microporous polyolefin membrane, so UHMWPE-2, PE-2, and PP-2 Based on the total amount of at least about 8%, or at least about 20%, or at least about 25%. In one form of (iii) and (iv) above, PP-2 can be at least one homopolymer or copolymer, based on the total amount of material of the second microporous layer, up to 50% by weight, Or 35% or less, or 25% or less, or about 2% to about 50%, or about 2% to about 15%, or about 3% to about 10%. In one form, the preferred PE-2 can be the same as PE-1, but can be selected independently. In one form, the preferred UHMWPE-2 can be the same as UHMWPE-1, but can be selected independently.

In addition to the first, second, third, fourth polyethylene and the first and second polypropylene, each of the first and second layer materials is optionally identified as a seventh polyolefin, for example, one or more polybutenes. -1, polypentene-1, poly-4-methylpentene-1, polyhexene-1, polyoctene-1, polyvinyl acetate, polymethyl methacrylate, polystyrene and ethylene α-olefin copolymers (excluding ethylene-propylene copolymers), etc. And can include one or more additional polyolefins that can have a Mw in the range of about 1 × 10 ⁴ to about 4 × 10 ⁶ . In addition to or in addition to the seventh polyolefin, the material of the first and second microporous layers may further comprise a polyethylene wax, for example in the range of about 1 × 10 ³ to about 1 × 10 ⁴ . Can be included.

  In one form, a method for producing a two-layer microporous membrane is provided. In another form, the microporous polyolefin membrane has at least three layers. For the sake of brevity, the production of microporous membranes will be described primarily with respect to two and three layer membranes.

  In one form, the three-layer microporous polyolefin membrane is between the first and third microporous layers and the first and third layers that make up the outer layer of the microporous polyolefin membrane (and optionally in plane contact). ) Includes a second (core) layer located. In another form, the first and third layers are produced from a first mixture of polymer and diluent and the second (core) layer is produced from a second mixture of polymer and diluent.

  In one form, a method for producing a multilayer, microporous polyolefin membrane is provided. The method comprises (1) mixing (eg, by blending) a first polymer or a mixture of polymers (eg, a polyolefin composition, etc.) and at least one diluent (which can be a solvent for the polymer). Combined, preparing a first mixture with an extruder of the type described herein, (2) a second polymer or mixture of polymers (eg, a second polyolefin composition, etc.) and at least one (second Mixing a second diluent (which can be a solvent for the polymer and is normally compatible with the first diluent) and preparing the mixture in an extruder of the type described herein, (3) For example, extruding the first mixture through a first die and the second mixture through a second die and then laminating the extruded mixture or passing the first and second mixture through a coextrusion die. (4) optionally cooling the multilayer extrudate to form a multilayer, gel-like sheet (cooled extrudate), (5) the extrudate. Alternatively, the method includes a step of removing at least a part of the first and second diluents from the cooled extrudate to produce a multilayer, microporous membrane. Optionally, the membrane can be the subject of any of the following optional steps. That is, these steps are performed between (6) the step of drying the membrane, the step of stretching the membrane or the dried membrane (7), and / or between steps (4) and (5). Step (8) of optional hot solvent treatment. After the step (6), an optional step (9) for stretching a multilayer or microporous membrane, an optional heat treatment step (10), a crosslinking step (11) using an arbitrary ionizing radiation, and an optional hydrophilic treatment step ( 12) etc. can be performed. Such membranes and membrane production methods are described in PCT publications WO 2008/016174, US 2008/0057388, and US 2008/0057389.

  In one form, the first and second polymers comprise the above-described polyolefin resin mixed to produce the first and second mixtures, for example, by dry blending or compounding with each of the first and second diluents. Each of which is produced from a polyolefin composition. Optionally, the first and second mixtures can include a variety of additives such as one or more provided antioxidants, silica fine powders (pore enhancers). These additives are used in concentrations that do not significantly reduce the desired properties of the multilayer, microporous polyolefin membrane.

  The first and second diluents (which may be the same diluent) are preferably the solvents used for the first and / or second polymer and are liquid at room temperature. While not wishing to be bound by any theory or model, the use of a liquid solvent to form the first and second mixtures can stretch the gel sheet at a relatively high stretching ratio. It is believed to enable the implementation of. In one form, the first diluent is at least one aliphatic, alicyclic, or aromatic hydrocarbon, such as nonane, decane, decalin, p-xylene, undecane, dodecane, liquid paraffin, etc. Mineral oil distillate having a boiling point comparable to that of hydrocarbons, and phthalic acid which is liquid at room temperature, such as dibutyl phthalate and dioctyl phthalate. In one form, if it is desired to obtain a multi-layer extrudate having a stable liquid diluent content, a non-volatile liquid solvent such as liquid paraffin as the diluent, alone or in combination with other solvents And can be used. Optionally, a diluent that is miscible when blended with polyethylene, but solid at room temperature, can be used alone or in combination with other liquid diluents. Such solid diluents can include, for example, stearyl alcohol, seryl alcohol, paraffin wax, and the like.

  The viscosity of the first and second diluents is not a critical parameter. For example, the viscosity of the diluent can range from about 30 cSt to about 500 cSt, or from about 30 cSt to about 200 cSt at 25 ° C. Although not an important parameter, if the viscosity at 25 ° C. is lower than about 30 cSt, it may be more difficult to prevent foaming of the mixture, which may make formulation difficult. On the other hand, if the viscosity is higher than about 500 cSt, it may be more difficult to remove the diluent from the multilayer, microporous polyolefin membrane.

  In one form, resin etc. which are used for production of the 1st polyolefin composition are compounded in a twin screw extruder or a mixer etc., for example. For example, conventional extruders (or mixers or mixer-extruders) such as twin screw extruders are used to mix resins and the like to form first and second polymers or polymer mixtures. Rukoto can. The diluent can be added at a fixed point to the polymer (or alternatively the resin used to produce the polymer or mixture of polymers) in a manner as described in connection with the extruder. For example, in one form, when the polyolefin composition and diluent are combined, either (i) before the start of mixing, (ii) during the polymer-diluent mixing, or (iii) after mixing, for example, By feeding the compounded or partially compounded polyolefin composition with a diluent in a second extruder or an extruder section located downstream of the extruder section used in compounding the polyolefin composition A portion of the diluent is added to the polyolefin composition (or compound thereof).

  When an extruder of the type disclosed herein is used, the screw can be characterized by the L / D ratio of the screw length L of the twin screw extruder to the screw diameter D. The L / D ratio can be in the range of about 20 to about 200 or about 25 to about 100, for example. The parameter is not critical, but if L / D is less than about 20, compounding can be more difficult. Also, higher extruder speeds are required to prevent excessive residence time of the polymer-diluent mixture in a twin screw extruder that can cause undesirable molecular weight reduction when L / D is higher than about 100. May be. Although not a critical parameter, the cylinder (or hole) of a twin screw extruder can have an inner diameter in the range of about 30 mm to about 100 mm, for example.

  The amount of the first polymer composition in the first mixture is not critical. In one form, the amount of the first polymer in the first mixture is greater than or equal to 1% by weight, such as from about 1% to about 75% by weight, for example from about 20% to about 40%, based on the weight of the mixture. It is in the range of wt%.

  The second mixture can be prepared in the same way that is used to prepare the first mixture. For example, the second mixture can be prepared by blending the second diluent and the second polymer.

  The amount of the second polymer composition in the second mixture is not critical. In one form, the amount of the second polymer in the second mixture is 1 wt% or more, such as from about 1 wt% to about 75 wt%, such as from about 20 wt% to about 40 wt%, based on the weight of the mixture. It is in the range of wt%.

  In one embodiment, two extruders are used in series with a twin screw extruder located upstream of the single screw extruder. The filter is located downstream of each extruder and can remove fine particles such as catalyst fine powder, unmixed polymer, metal particles, and the like. Metal particles (such as those worn from the inner surface of an intimate extruder) are particularly problematic for battery separator films because they can cause short circuits in the film. A fine filter, such as one having a pore size such as 100 μm or less, or 40 μm or less, or 20 μm or less, in the range of 20 μm to 50 μm, can be used for removing the particles. It has been observed that the introduction of such a filter, particularly downstream of the second extruder, can cause phase separation of the polymer-diluent mixture. This problem can be exacerbated when pumping means such as gear pumps are used to eliminate the filter pressure drop. In these cases, it has been discovered that such phase separation may be cured by the insertion of mixing means such as a static mixer upstream of the die. Using a mixing means upstream of the die improves the temperature uniformity of the polymer-diluent mixture and reduces the amount of polymer-diluent phase separation. It is also believed that the use of such mixing means causes a more uniform concentration of polymer and diluent in the polymer-diluent mixture. The increase in homogeneity is believed to reduce the amount of polymer-diluent phase separation. While not wishing to be bound by any theory or model, the occurrence of polymer-diluent phase separation is very sensitive to the temperature of the polymer-diluent mixture and the amount of polymer in the mixture. It is believed. Variations in polymer concentration that occur (eg, when a portion of the polymer is separated from the mixture by a fine mesh of the filter) result in a polymer-diluent phase separation that produces a high concentration phase of unwanted diluent. there is a possibility. The high concentration phase of the diluent, when extruded through a die, produces an extrudate having unwanted thickness uniformity and / or compositional non-uniformity.

  In one embodiment, process conditions such as polymer and diluent types and amounts, processing temperatures and flow rates, and die sections are selected from those disclosed in PCT publications WO2008 / 016174, US2008 / 0057388 and US2008 / 0057389. Is done.

  Single layer extrusion dies can be used to form extrudates that can be laminated. In one form, adjacent or connectable extrusion dies are used to form the extrudate. When the first extruder includes a first mixture and the second extruder includes a second mixture, the first and second sheet dies are connected to the first and second extruders, respectively. Although not critical, lamination is generally easier to achieve if the extruded first and second mixtures are still at approximately the extrusion temperature. In one form, the extrudates are laminated prior to cooling. In another form, after cooling, the extrudates are laminated. In yet another form, lamination is performed after at least a portion of the first and second diluents are removed. That is, in this embodiment, the membrane is laminated instead of the extrudate. In yet another form, coextrusion is used to produce multi-layer extrudates without lamination.

  For example, in one form, when the first and third dies include a first mixture and the second die includes a second mixture, the first, second, and third dies are molds described herein. Connected to the first, second and third extruders. In this form, an outer layer comprising the extruded first mixture and one intermediate comprising the extruded second mixture constitute a laminated extrudate.

  In yet another form, when the second die includes a first mixture and the first and third dies include a second mixture, the first, second, and third dies are of the type described herein. Connected to the first, second and third extruders. In this form, an outer layer comprising the extruded second mixture and one intermediate comprising the extruded first mixture constitute a laminated extrudate.

  The die gap is generally not important. For example, an extrusion die can have a die gap of about 0.1 mm to about 5 mm. Also, die temperature and extrusion speed are not important parameters. For example, the die can be heated at a die temperature in the range of about 140 ° C. to about 250 ° C. during extrusion. For example, the extrusion rate can range from about 0.2 m / min to about 15 m / min. The layer thickness of the layered extrudate can be selected independently. For example, the synthetic sheet can have a skin or surface layer that is relatively thick compared to the thickness of the intermediate layer of the layered extrudate.

  A cooled extrudate, such as a multilayer, gel-like sheet or the like, can be obtained, for example, by cooling. The cooling rate and cooling temperature are not particularly important. For example, a multilayer, gel-like sheet will have a temperature (cooling temperature) of the multilayer, gel-like sheet that is approximately equal to (or below) the gelatin temperature of the multilayer, gel-like sheet at a cooling rate of at least about 50 ° C./min. Can be cooled down to In one form, the extrudate is cooled to a temperature of about 25 ° C. or less to form a multilayer gel-like sheet.

In one form, the first and second diluents are removed (or replaced) from the multilayer gel-like sheet to form a gel-like sheet with the diluent removed. A replacement (or cleaning) solvent can be used to remove (wash away or replace) the first and second diluents. The choice of cleaning solvent is not critical as long as it is capable of dissolving or replacing at least a portion of the first and / or second diluent. . For example, suitable cleaning solvents include saturated hydrocarbons such as pentane, hexane and heptane, chlorinated hydrocarbons such as methylene chloride and carbon tetrachloride, ethers such as diethyl ether and dioxane, ketones such as methyl ethyl ketone, trifluoroethane, Linear fluorocarbons such as C ₆ F ₁₄ and C ₇ F ₁₆ , cyclic hydrofluorocarbons such as C ₅ H ₃ F _7, hydrofluoroethers such as C ₄ F ₉ OCH ₃ and C ₄ F ₉ OC ₂ H ₅ , C ₄ F _It includes one or more volatile solvents such as perfluoroethers such as ₉ OCF ₃ , C ₄ F ₉ OC ₂ H ₅ .

  The diluent removal method is not critical and any method capable of removing significant amounts of diluent can be used, including conventional solvent removal methods. For example, a multilayer, gel-like sheet can be cleaned by immersing the sheet in a cleaning solvent and / or rinsing the sheet with a cleaning solvent. The amount of cleaning solvent used is not critical and generally depends on the method selected for diluent removal. In one form, based on the weight of the gel-like sheet, the diluent is removed from the gel-like sheet (eg, by washing, etc.) until the remaining amount of diluent in the multilayer gel-like sheet is less than 1% by weight. .

In one form, a diluent-removed multilayer, gel-like sheet obtained by removing the diluent is dried to remove the cleaning solvent. Any method capable of removing the cleaning solvent can be used, including conventional methods such as heat drying, air drying (dynamic air) and the like. The temperature of the gel-like sheet during drying (ie, drying temperature) is not critical. For example, the drying temperature can be equal to or lower than the crystal dispersion temperature Tcd. Tcd is the lower _one of the crystal dispersion temperature Tcd ₁ of polyethylene in the first resin and the crystal dispersion temperature Tcd ₂ of polyethylene in the second resin. For example, the drying temperature can be at least 5 ° C. lower than the crystal dispersion temperature Tcd. The crystal dispersion temperature of polyethylene in the first and second resins can be determined by measuring the temperature characteristics of dynamic viscoelasticity of polyethylene according to ASTM D4065. In one form, the polyethylene in at least one of the first or second resins has a crystal dispersion temperature in the range of about 90 ° C to about 100 ° C.

  Although not critical, drying can be performed on a dry basis, i.e., based on the weight of the dried multilayer, microporous polyolefin membrane until the remaining amount of cleaning solvent is about 5 wt% or less. In another form, drying can be performed until the remaining amount of cleaning solvent is about 3 wt% or less on a dry basis.

  In order to obtain a stretched multilayer, gel-like sheet, the multilayer, gel-like sheet can be stretched prior to the step of removing the diluent.

  Neither the selection of the stretching method nor the extent of the stretching ratio is particularly important. In one form, stretching can be accomplished by one or more tenter stretching methods, roller stretching methods, or inflation stretching methods (eg, using air or the like). Selection is not critical, but stretching can be done uniaxially (ie, either in the flow direction or transverse direction) or biaxially (in both the flow direction and transverse direction). I can do it. In the case of biaxial stretching (also referred to as biaxial stretching), the stretching is simultaneous biaxial stretching, sequentially stretching along the planar axis and other axes (eg, first in the transverse direction and then in the flow direction, etc. ) Sequential stretching or multi-stage stretching (for example, a combination of simultaneous biaxial stretching and sequential stretching).

  The draw ratio is not critical. In the form in which uniaxial stretching is used, the linear stretch ratio can be, for example, about 2 times or more, or about 3 to about 30 times, and the like. In a form in which biaxial stretching is used, the linear stretching ratio can be, for example, about 3 times or more in any lateral direction. In another form, the linear magnification resulting from stretching is at least about 9 times, or at least about 16 times, or at least about 25 times in area magnification.

The temperature of the multilayer, gel-like sheet during stretching (ie, the stretching temperature) is not critical. In one form, the temperature of the gel-like sheet during stretching can be in the range of about (Tm + 10 ° C.) or less, or optionally above Tcd and below Tm. Here, Tm is the lower temperature of the melting point Tm ₁ of polyethylene in the first resin and the melting point Tm ₂ of polyethylene in the second resin.

  The commonly used stretching makes it easier to produce relatively high mechanical strength multilayer, microporous polyolefin membranes having relatively large pore sizes. Such a multilayer, microporous membrane is believed to be particularly suitable for use as a battery separator.

  As described in Japanese Patent No. 3,347,854 B2, stretching is optionally performed with a temperature gradient in the thickness direction (ie, in a direction substantially perpendicular to the plane of the multi-layer, microporous polyolefin membrane). Can be done. In this case, stretching makes it easier to produce multilayer, microporous polyolefin membranes with excellent mechanical strength.

  Although not required, multilayer, gel-like sheets can be treated with a hot solvent. When used, the hot solvent treatment is believed to provide fibers having a relatively thick vein-like structure (such as that formed by stretching a multilayer gel-like sheet). Details of this method are described in International Patent Publication No. WO2000 / 20493.

  In one form, the dried multilayer, microporous membrane can be stretched at least uniaxially. The selection of the stretching method is not important, and a conventional stretching method such as a tenter method can be used. As described above, when a multilayer gel-like sheet is stretched, stretching of the dried multilayer, microporous polyolefin membrane can be accomplished by dry-stretching, re-stretching, or dry-orientation. ).

  The temperature of the dry multilayer, microporous membrane during stretching (“dry stretching temperature”) is not critical. In one form, the dry stretching temperature is less than or equal to the melting point Tm, for example, in the range of about the crystal dispersion temperature Tcd to about the melting point Tm. In one form, the dry stretching temperature ranges from about 90 ° C to about 135 ° C or from about 95 ° C to about 130 ° C.

  When dry stretching is used, the draw ratio is not critical. For example, the draw ratio of the multilayer, microporous membrane may be in the range of about 1.1 times to about 2.5 times or about 1.1 times to about 2.0 times in at least one side (plane) direction. I can do it.

  In one form, the dried multilayer, microporous membrane can be treated with a hot solvent. In one form, the heat treatment includes heat setting and / or annealing. When heat setting is used, it can be done using conventional methods such as the tenter method and / or the roller method. Although not critical, the temperature of the dried multilayer, microporous polyolefin membrane during heat setting (ie, the “heat setting temperature”) can range from Tcd to about Tm.

  Annealing is different from heat setting in that it is a heat treatment without a load applied to the multilayer, microporous polyolefin membrane. The choice of annealing method is not critical and can be done, for example, using a heating chamber with a belt conveyor or an air-floating heating chamber. Alternatively, after heat setting, annealing can be performed with the tenter clip loosened. The temperature of the multilayer, microporous polyolefin membrane during annealing is approximately at or below the melting point Tm, in the range of about 60 ° C to (Tm-10 ° C), or in the range of about 60 ° C to (Tm-5 ° C). I can do it.

  In one form, the multi-layer, microporous polyolefin membrane is cross-linked (eg, by ionizing radiation such as a-line (3-line, 7-line, electron beam, etc.) or hydrophilic treatment. (In other words, treatment for making the multi-layer, microporous polyolefin film more hydrophilic (for example, monomer / graft treatment, surfactant treatment, corona discharge treatment, etc.)).

  Although extrusion has been described for the production of two-layer and three-layer extrudates, the extrusion process is not limited thereto. For example, a plurality of dies and / or molds can be used to produce a multi-layer extrudate having 4 or more layers using the principles of extrusion dies and extrusion methods disclosed herein.

  All patents, test procedures, and other references cited herein, including priority documents, are comprehensive in their jurisdiction to the extent that their disclosure is consistent with the present invention and their incorporation is permitted. Is incorporated by reference.

  While specific embodiments of the present invention have been disclosed in detail, various other modifications will be apparent to those skilled in the art and may be readily made by those skilled in the art without departing from the spirit and scope of the present invention. It is understood that this can be done. Accordingly, the appended claims are not intended to be limited by the examples and the description set forth herein, but rather, the claims are intended to be understood by those of ordinary skill in the art to which this disclosure belongs. It is to be construed to include all novel and patentable features provided herein, including all features that are treated as equivalent.

  Where numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated.

  Several aspects of embodiments of the invention are described in the following examples. The invention is not limited to the illustrated embodiments.

Example 1
The polyolefin resin was dry mixed as follows. That is, (i) an ultra high molecular weight polyethylene (UHMWPE) having a weight average molecular weight (Mw) of 1.9 × 10 ⁶ and a molecular weight distribution of 5.09 (“MWD” defined as Mw / Mn) and having a mass of 20%. 99.625 parts polyolefin (PO) composition by weight, (ii) 7.5 × 10 ⁵ Mw and 11.85 MWD, 80% by weight high density polyethylene (HDPE), and (Iii) Dry mix of tetrakis (methylene-3- (3,5-ditertiarybutyl-4-hydroxyphenyl) -propionic acid) methane as an antioxidant at 0.375 parts by mass.

  30 parts by weight of liquid paraffin solvent having a viscosity of 50 cSt at 40 ° C. were introduced into the extruder. Based on the total amount of liquid paraffin, 70% by weight of liquid paraffin is introduced at the first fluid inlet 32 in the dispersion stage, and on the basis of the total amount of liquid paraffin, 30% by weight of liquid paraffin is introduced in the second mixing stage. It was introduced at the fluid inlet 33. The temperatures at each stage of the extruder were all in the range of 150 ° C to 200 ° C.

Using a High Temperature Size Exclusion Chromatograph equipped with a differential refractive index detector (DRI), or “SEC” (GPC PL 220, Polymer Laboratories) , Mn and MWD were measured. Three PLgel Mixed-B columns (available from Polymer Laboratories) were used. The nominal flow rate was 0.5 cm ³ / min and the nominal injection volume was 300 μL. The transfer line, column, and DRI detector were placed in an oven maintained at 145 ° C. It was measured according to the procedure disclosed in “Macromolecules, Vol. 34, No. 19, pages 6812-6820 (2001)”.

  The GPC solvent used was filtered Aldrich reagent grade 1,2,4-trichlorobenzene (TCB) containing about 1000 ppm butylated hydroxytoluene (BHT). The TCB was degassed with a direct degassing agent before introduction into the SEC. A polymer solution was prepared by placing the dry polymer in a glass container, adding the desired amount of the above TCB solvent, and then heating the mixture at 160 ° C. with continuous stirring for about 2 hours. The concentration of the UHMWPE solution was 0.25 to 0.75 mg / ml. Prior to injection into GPC, the sample solution was individually filtered through a 2 μm filter using a model SP260 Sample Prep Station (available from Polymer Laboratories).

  The separation efficiency of the column set was measured with a calibration curve generated using 17 individual polystyrene standards with a Mp ranging from about 580 to about 10 million used to generate a calibration curve. Polystyrene standards were obtained from Polymer Laboratories (Amherst, Mass.). A calibration curve (logMp vs. retention capacity) was generated by recording the retention capacity at the peak of the DRI signal used in each PS standard and fitting the data set to a two-stage polynomial. Samples were analyzed using IGOR Pro, available from Wave Metrics, Inc. (Wave Metrics, Inc).

  A polyethylene composition of 30 parts by mass was placed in the inlet hopper 24 of a co-rotating, twin-screw extruder having a screw configuration as shown in FIG. 3, and the composition was extruded to prepare a polyethylene solution. The extruder is a Model TEX54 twin screw extruder obtained from Nippon Steel Works in Tokyo (Japan).

Example 2
The extruder of FIG. 9 is used and 55% by weight of liquid paraffin is introduced at the first fluid inlet in the dispersion stage based on the total amount of liquid paraffin, and 45% by weight of liquid paraffin is based on the total amount of liquid paraffin. A polyethylene solution was produced in the same manner as in Example 1 except that it was introduced at the second fluid inlet in the second mixing stage.

Example 3
Based on the total amount of liquid paraffin, 90% by weight of liquid paraffin is introduced at the first fluid inlet of the dispersion stage, and based on the total amount of liquid paraffin, 10% by weight of liquid paraffin is introduced into the second fluid in the second mixing stage. A polyethylene solution was produced in the same manner as in Example 1 except that it was introduced at the inlet.

Comparative Example 1
A polyethylene solution was produced in the same manner as Example 1 except that all liquid paraffin was introduced at the first fluid inlet in the dispersion stage.

Characteristics The characteristics of the polyethylene solutions of Examples 1-3 and Comparative Example 1 were measured by the following method. The results are shown in Table 1.

(1) Polyethylene solution extrusion rate (kg / h)
The extrusion rate of the polyethylene solution is the amount of polyethylene solution per time that is extruded from the twin screw extruder. The weight of the extruded polyethylene solution per 36 seconds was measured 5 times and averaged. The scale is an electronic balance manufactured by Sartorius Corporation.

(2) Melt index (g / 10 min)
The melt index of the polyethylene solution was measured according to ASTM D1238. If the polymer and solvent are not homogeneously mixed or if the polymer is degraded due to shear stress in a twin screw extruder, the melt index can be higher.

  Table 1 shows that examples of the present invention enable high extrusion rates while providing polyethylene solutions with a stable melt index and uniform appearance. On the other hand, the polyethylene solution of the comparative example could not be successfully extruded although the extrusion rate of the polyethylene solution was lower than those of Examples 1, 2, and 3.

  It is very difficult to uniformly mix and extrude a composition containing a small amount of polymer dispersed in a large amount of liquid. In general, more uniform mixing requires a lower extrusion rate. In one aspect, the present invention provides an extruder such as that illustrated and described in Examples 1 to 3 above, where the diluent is partially present in the dispersed and mixed phases of the extruder, respectively. Based on discovery that can provide desirable uniform mixing at speed.

  By using such an extruder capable of providing a diluent in the manner described above, it is possible to provide better membrane properties, more stable manufacturing operations, and higher productivity.

  The disclosed invention is further illustrated, but not limited, by the following embodiments.

1. An extruder for mixing polymer and diluent,
(A) an elongate housing having an inlet end, an outlet end, and at least one hole disposed in the housing;
(B) at least one elongate extruder shaft disposed within the at least one bore and having a rotational axis; and (c) a plurality of elongate extruder shafts positioned along the at least one elongate extruder shaft in a fixed angle relationship to each other. An extruder screw section, wherein the plurality of extruder screw sections are selected to form a plurality of extruder stages, the plurality of extruder stages including an injection stage and a dispersion stage, wherein the plurality of extruder screw sections Forming said dispersion stage comprising at least one first kneading section comprising a plurality of kneading disks having at least one flight tip, each adjacent flight tip being progressively at an angle θ of 0 ° <θ <90 ° The extruder including the plurality of extruder screw sections to be offset.

2. The number of kneading discs is greater than 10, and the offset angle between the last kneading disc of the at least one first kneading section and the first kneading disc of the adjacent kneading section is selected to be equal to about 0 °. The extruder of embodiment 1.

3. The extruder of embodiment 1 or 2, wherein the plurality of extruder stages further comprises a first mixing stage, a second mixing stage, and an effluent stage.

4). The extrusion of any of embodiments 1-3, wherein the at least one elongated extruder shaft has a square, pentagonal, hexagonal or octagonal cross section or a cross section defined by a perimeter formed by a plurality of corrugations. Machine.

5. The extruder of any of embodiments 1 to 4, wherein 40 ° ≦ θ ≦ 50 °.

6). Embodiment 6. The extruder of any of embodiments 1 to 5, wherein the number of kneading disks in the at least one first kneading section is greater than 15.

7). The dispersing stage further includes at least one second kneading section, the at least one second kneading section includes five kneading disks, each adjacent flight tip being progressive at an angle θ ranging from 40 ° to 50 °. The extruder of any of embodiments 1 to 6, offset to

8). The dispersion stage further includes at least one second kneading section, the at least one second kneading section includes five kneading disks, each adjacent flight tip being progressively offset at an angle θ equal to about 45 °. The extruder of any of embodiments 1 to 7.

9. A twin screw extruder for mixing polymer and diluent,
(A) an elongated housing having an inlet end, an outlet end, an extruder shaft length L, and a pair of intersecting holes disposed within the housing;
(B) a pair of elongated extruder shafts each having a rotational axis, the pair of elongated extruders disposed within the pair of intersecting holes and operable in at least one rotational direction; shaft,
(C) a plurality of extruder screw sections located along the pair of elongated extruder shafts in a fixed angle relationship to each other, wherein the plurality of extruder screw sections are selected to form a plurality of extruder stages; An injection stage in which the plurality of extruder stages have a length Li of about 3% L ≦ Li ≦ about 30% L; a dispersion stage having a length Ld of about 10% L ≦ Ld ≦ about 35% L; A first mixing stage having a length Lm1 of 5% L ≦ Lm1 ≦ about 45% L, a second mixing stage having a length Lm2 of about 0% L ≦ Lm2 ≦ about 50% L, and about 0% L ≦ Lo The plurality of extruder screw sections comprising an outflow stage having a length Lo of about 40% L;
The twin screw extruder comprising: (d) a material inlet adjacent to the injection end of an elongated barrel; and (e) a first fluid inlet located within the dispersion stage for introducing solvent.

10. The plurality of extruder screw sections forming the dispersion stage include at least one first kneading section including a plurality of kneading disks having at least one flight tip, each adjacent flight tip being 0 ° <θ <90. Progressively offset at an angle θ of °,
The twin-screw extruder according to embodiment 9.

11. The number of the kneading disks in the at least one first kneading section is greater than 10, and the offset angle between the last kneading disk in the at least one first kneading section and the first kneading disk in the adjacent kneading section is about Embodiment 11. A twin screw extruder according to embodiment 9 or 10 selected to be equal to 0 °.

12 The number of kneading disks and the angle θ of at least one first kneading section are substantially equal to the offset angle between the last kneading disk of the at least one first kneading section and the first kneading disk of the adjacent kneading section. Embodiment 12 The twin-screw extruder according to any one of embodiments 9 to 11, which is selected so that it is possible to install adjacent kneading sections so as to be equal to the angle θ.

13. Embodiment 13. The twin-screw extruder of any of embodiments 9 to 12, further comprising a second fluid inlet located within the second mixing stage for introducing a portion of the diluent.

14 14. The twin screw extruder of embodiment 13, further comprising a third fluid inlet located within the second mixing stage.

15. The twin screw extruder of embodiment 14 wherein the third fluid inlet is located downstream of the second fluid inlet.

16. Embodiment 16. The twin screw extruder according to any of embodiments 11 to 15, wherein the axes of rotation are substantially parallel and the elongated extruder shaft is co-rotating or counter-rotating.

17. A method of extruding a mixture of a polymer and a diluent, comprising:
(A) blending the polymer at the rate P in the injection stage and leading the blended polymer to the dispersion stage of the extruder (b) adding at least part of the diluent to the blended polymer at the speed stage S1 A step of dispersing a diluent in the polymer, and further introducing the dispersed diluent to the first mixing step, wherein the diluent has a lower viscosity than the polymer, and (c) the first mixing step Wherein the polymer blended with the dispersed diluent is blended to produce a third stage product, wherein the third stage product is (i) the mixture in the first phase. (Ii) part of the diluent in the second phase separated from the first phase, and (iii) part of the polymer in the third phase separated from the first and second phases,
Including
The method, wherein the mixing energy of the first mixing stage is greater than the mixing energy in either the injection stage or the dispersion stage.

18. 18. The method of embodiment 17, wherein the first phase is produced at a rate of R, wherein R is about 0.9x (P + S1) or higher.

19. Adding at least a second portion of the diluent to the blended polymer of the first mixing step and / or the second mixing step at a rate of S2, and dispersing the second portion of the diluent in the polymer. The method of embodiment 17 or 18, further comprising, wherein the weight ratio of S1 / S2 ranges from about 51 wt% / 49 wt% to about 99 wt% / 1 wt%.

20. Embodiment 20. The method of any of embodiments 17-19, wherein the second phase is produced at a rate not exceeding 0.05xS1.

21. Embodiment 21. The method of any of embodiments 17 to 20, wherein the third phase is produced at a rate not exceeding 0.05 x P.

22. Embodiment 22. The method of any of embodiments 17 to 21, wherein the rate of diluent counter flow from the second region to the first region does not exceed 0.1 x S1.

23. (E) extruding the mixture through an extrusion die, wherein the extrusion die comprises a perforated die outlet through which a stream of polymer solution is extruded, and (f) cooling the extrudate. Embodiment 23. The method of any of embodiments 17-22, further comprising forming a cooled extrudate.

24. (G) removing the diluent from the cooled extrudate to form a cooled extrudate from which the diluent has been removed;
Embodiment 17 further comprising: (h) drying the cooled extrudate from which the diluent has been removed to form a microporous membrane; and (i) stretching the cooled extrudate and / or the microporous membrane. 1 to 23.

25. The extruder is
(A) an elongated housing having an inlet end, an outlet end, an extruder shaft length L, and a pair of intersecting holes disposed within the housing;
(B) a pair of elongated extruder shafts each having a rotational axis, the pair of elongated extruders disposed within the pair of intersecting holes and operable in at least one rotational direction; shaft,
(C) a plurality of extruder screw sections located along the pair of elongated extruder shafts in a fixed angle relationship to each other, wherein the plurality of extruder screw sections are selected to form a plurality of extruder stages; An injection stage in which the plurality of extruder stages have a length Li of about 3% L ≦ Li ≦ about 30% L; a dispersion stage having a length Ld of about 10% L ≦ Ld ≦ about 35% L; A first mixing stage having a length Lm1 of 5% L ≦ Lm1 ≦ about 45% L, a second mixing stage having a length Lm2 of about 0% L ≦ Lm2 ≦ about 50% L, and about 0% L ≦ Lo The plurality of extruder screw sections comprising an outflow stage having a length Lo of about 40% L;
(D) a material inlet adjacent to said injection end of an elongated barrel; and (e) a first fluid inlet located within said dispersion stage for introducing a first portion of diluent, said dispersion stage Located within the first fluid inlet, and (f) the second mixing stage for introducing a second portion of diluent, located within a length of about 50% Ld from the beginning of the inlet. 25. The method of any of embodiments 17 to 24, wherein the method is a twin screw extruder including a second fluid inlet.

26. The product of any of embodiments 17 to 25.

27. 27. A battery separator film for a lithium ion battery produced by the method of any of embodiments 17 to 26.

Claims (25)

A system for producing an extrudate comprising a blended polymer and a diluent,
First extrusion means,
A second extrusion means located downstream of the first extrusion means and in fluid communication with the first extrusion means;
A pumping means located downstream of the second pushing means and in fluid communication with the second pushing means;
Separation means for removing at least a portion of any unmixed polymer from the effluent of the second extrusion means, the separation means located downstream of the second extrusion means and in fluid communication with the second extrusion means ,
The system comprising: mixing means located downstream of the separation means and in fluid communication with the separation means; and at least one die located downstream of the mixing means and in fluid communication with the mixing means. The second extrusion means comprises:
(A) an elongate housing having an inlet end, an outlet end, and at least one hole disposed in the housing;
(B) at least one elongate extruder shaft disposed within the at least one bore and having a rotational axis; and (c) a plurality of elongate extruder shafts positioned along the at least one elongate extruder shaft in a fixed angle relationship to each other. An extruder screw section, wherein the plurality of extruder screw sections are selected to form a plurality of extruder stages, the plurality of extruder stages including an injection stage and a dispersion stage, wherein the plurality of extruder screw sections Forming said dispersion stage comprising at least one first kneading section comprising a plurality of kneading disks having at least one flight tip, each adjacent flight tip being progressively at an angle θ of 0 ° <θ <90 ° The system of claim 1, wherein the system is a second extruder that includes the plurality of extruder screw sections that offset. The number of the kneading disks of the second extruder is more than 10, and the offset angle between the last kneading disk of the at least one first kneading section and the first kneading disk of the adjacent kneading section is about 0 °. The system of claim 2, wherein the systems are selected to be equal. The system of claim 2 or 3, wherein the plurality of extruder stages of the second extruder further comprises a first mixing stage, a second mixing stage, and an effluent stage. 3. The at least one elongated extruder shaft of the second extruder has a square, pentagonal, hexagonal or octagonal cross section or a cross section defined by a perimeter formed of a plurality of corrugations. 5. The system according to any one of 4. The first extrusion means is a first extruder, and the extruder is
(A) an elongated housing having an inlet end, an outlet end, an extruder shaft length L, and a pair of intersecting holes disposed within the housing;
(B) a pair of elongated extruder shafts each having a rotational axis, the pair of elongated extruders disposed within the pair of intersecting holes and operable in at least one rotational direction; shaft,
(C) a plurality of extruder screw sections located along the pair of elongated extruder shafts in a fixed angle relationship to each other, wherein the plurality of extruder screw sections are selected to form a plurality of extruder stages; An injection stage in which the plurality of extruder stages have a length Li of about 3% L ≦ Li ≦ about 30% L; a dispersion stage having a length Ld of about 10% L ≦ Ld ≦ about 35% L; A first mixing stage having a length Lm1 of 5% L ≦ Lm1 ≦ about 45% L, a second mixing stage having a length Lm2 of about 0% L ≦ Lm2 ≦ about 50% L, and about 0% L ≦ Lo The plurality of extruder screw sections comprising an outflow stage having a length Lo of about 40% L;
6. (d) comprising a material inlet adjacent to said inlet end of an elongated barrel and (e) a first fluid inlet located within said dispersing stage for introducing a portion of diluent. A system according to any of the above. In the first extruder, the plurality of extruder screw sections forming the dispersion stage includes at least one first kneading section including a plurality of kneading disks having at least one flight chip, each adjacent flight chip being The system of claim 6, wherein the system is progressively offset at an angle θ of 0 ° <θ <90 °. In the first extruder, the number of the kneading disks in the at least one first kneading section is more than 10, and the last kneading disk in the at least one first kneading section and the first kneading disk in the adjacent kneading section The system according to claim 6 or 7, wherein the offset angle between is selected to be equal to about 0 °. In the first extruder, the number of kneading disks and the angle θ of at least one first kneading section are determined by the last kneading disk of the at least one first kneading section and the first kneading disk of the adjacent kneading section. 9. A system according to any of claims 6 to 8, which is selected such that adjacent kneading sections can be installed such that an offset angle between them is substantially equal to the angle θ. The first extruder further comprises a second fluid inlet located in the second mixing stage for introducing diluent, wherein (i) the axis of rotation is substantially parallel; The system according to any of claims 6 to 9, wherein ii) the elongated extruder shaft is co-rotating or reciprocally rotating. The system according to claim 1, further comprising a second pumping means between the first extruding means and the second extruding means. A method of producing a polymer extrudate comprising:
(A) The step of mixing the polymer and diluent in the first extruder and transferring the effluent containing the mixed polymer and diluent therefrom (b) leading the effluent of the first extruder to the second extruder Process,
(C) leading the effluent of the second extruder to the first pumping means;
(D) separating the effluent from the first pumping means into a retentate and a filtrate;
(E) mixing the polymer and diluent with the filtrate to provide a mixed filtrate; and (f) extruding the mixed filtrate through at least one die.
Said method. The method of claim 12, wherein the retentate is removed from the step. The method according to claim 12 or 13, wherein the first extruder is a twin screw extruder and the second extruder is a single screw extruder. 15. The method according to any of claims 12 to 14, further comprising the steps of filtering the effluent of the first pumping means, directing the effluent from the first gear pump to the second extruder, and removing the filtrate from said step. . The method according to any one of claims 12 to 15, wherein the extrudate is produced at a rate of 20 kg / hr or more. 17. A method according to any of claims 12 to 16, wherein the polymer and diluent mixed in the first and second extruders are exposed to a temperature in the range of 150C to 250C. 18. A method according to any of claims 12 to 17, wherein the polymer is one or more polyolefins. The diluent comprises liquid paraffin, and the amount of the liquid paraffin in the blended polymer and diluent of the first extruder ranges from 40% to 90% by weight, based on the weight of the polyolefin and liquid paraffin. The method of claim 18, wherein: 20. A method according to any of claims 12 to 19, further comprising the steps of directing the effluent from the first extruder to a second pumping means and directing the effluent of the second pumping means to the second extruder. 21. A method according to any one of claims 12 to 20, wherein the first pumping means is a gear pump. The method according to any of claims 12 to 21, wherein the second pumping means is a gear pump. A microporous film produced by the method according to claim 12. A battery separator film for a lithium ion battery produced by the method according to claim 12. An extruder for mixing polymer and diluent,
(A) an elongate housing having an inlet end, an outlet end, and at least one hole disposed in the housing;
(B) at least one elongate extruder shaft disposed within the at least one bore and having a rotational axis; and (c) a plurality of elongate extruder shafts positioned along the at least one elongate extruder shaft in a fixed angle relationship to each other. An extruder screw section, wherein the plurality of extruder screw sections are selected to form a plurality of extruder stages, the plurality of extruder stages including an injection stage and a dispersion stage, wherein the plurality of extruder screw sections Forming said dispersion stage comprising at least one first kneading section comprising a plurality of kneading disks having at least one flight tip, each adjacent flight tip being progressively at an angle θ of 0 ° <θ <90 ° The extruder including the plurality of extruder screw sections to be offset.

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