JP5127000B2 - Extrusion mold with cantilever-shaped mold lip adjustment system - Google Patents

Description

  The present invention generally relates to an extrusion apparatus for producing a film or sheet of a thermoplastic resin.

  Extrusion molds are used in manufacturing processes that make a variety of products. For example, certain extrusion molds are used to form plastic materials into thin films, sheets, or extended shapes. Two or more different materials that make up separate molten layers (e.g., thermoplastic materials) are integrated in an extrusion mold under pressure to make up as a single laminate material A technique of melt lamination molding method including a process has been developed. Such a process uses laminar flow theory that allows two or more molten layers to be integrated under suitable operating conditions in a common flow path without being mixed at the contact interface. Such multilayer extrusion systems have come to be used as a convenient method for molding homogeneous or dissimilar multilayer materials from polymer solutions.

  Various extrusion dies have been manufactured for extruding multilayer films from polymer solutions. A common form of such an apparatus is one that uses a first mold part that integrates layers of various materials. The integrated material is then planarized and extruded through the second mold part. An example of such a type of device is disclosed in US Pat. No. 5,316,703, which is hereby incorporated by reference in its entirety. When manufacturing a multilayer sheet or a multilayer film, there is a demand for having a uniform thickness in the width direction or the lateral direction (TD) of the extruded sheet. There was a limit to the effectiveness of the device.

  Mold assembly can be modularized and is typically assembled from a plurality of parts, forming a mold station as an integrated device. For example, the mold assembly can be composed of a first mold part and a second mold part. The first mold part and the second mold part constitute a component that allows fluid to be taken into the mold assembly and further pushed out of the mold assembly. The first mold part is provided with a first mold lip part, and the second mold part is provided with a second mold lip part. A feed gap (gap for extruding the molten polymer) that determines the thickness of the fluid film extruded from the mold assembly is formed between the first and second mold lip portions.

  The central feed type extrusion die is generally used in today's resin industry association. The flow of molten polymer entering the manifold branches and, as a result of the branching, is divided into tributaries that flow in opposite directions towards the ends of the manifold. Each tributary flows from the center of the manifold to each end of the manifold, resulting in a pressure drop.

  Typically, a central feed extrusion mold is a teardrop-like flat manifold (which may be in the form of a coat hanger manifold), a tail fin manifold, or T A mold manifold is provided. In order to overcome the pressure drop and ensure that the flow volume is substantially uniform over the entire width of the flow, this type of mold is provided with a transition region flow path to compensate for fluid pressure. Further, it is known that the extrusion die of the center feed type includes a flow path in a transient region for compensating for a two-stage fluid pressure. Such devices are exemplified in U.S. Patent No. 4,372,739 (Vetter et al.) And U.S. Patent No. 5,256,052 (Cloeren).

  The mold assembly for extruding the polymer solution can be a fixed extrusion gap or a flexible extrusion gap. In the case of a fixed extrusion gap, the mold lip portions do not move relative to each other, and the thickness dimension of the extrusion gap is always the same. In the case of a flexible extrusion gap, in order to be able to adjust the thickness dimension of the flexible extrusion gap over the width direction of the mold assembly, the mold lip on one side is connected to the mold lip on the other side. It can be moved relative to the part. Generally, the flexible extrusion gap is such that the first mold part is flexible between the rear part and the front part of the first mold part (the first mold lip part comes into contact with this part). This is realized by assembling the first mold part so as to have a web part. The flexible extrusion gap is also realized by means for moving the front part of the first mold part in a local region. By moving the front part, the mold lip part is adjusted relative to the other mold lip part, so that the thickness of the extrusion gap in the desired local area is adjusted. become.

  By utilizing a flexible extrusion gap, a conventional mold assembly design usually allows local adjustment of the extrusion gap to adapt to specific operating conditions. In general, this is accomplished as follows. First, on the downstream side of the mold lip part, the thickness is measured across the width direction of the finished resin sheet or film, adjusted with one or more adjustment bolts, and then the thickness of the finished resin sheet or film The thickness is measured again, and the operation is repeated until the thickness distribution of the film falls within the allowable range.

  With respect to the production of special films such as microporous polyolefin membranes, there are additional requirements in the design of extrusion dies for producing such films. Microporous polyolefin membranes are primary batteries, lithium ion secondary batteries, lithium polymer secondary batteries, nickel / hydrogen secondary batteries, nickel / cadmium secondary batteries, nickel / zinc secondary batteries, silver / zinc secondary batteries. It is useful as a separator for secondary batteries such as batteries. When microporous polyolefin membranes are used as battery separators, especially when used as lithium ion battery separators, the performance of the membrane has a very strong impact on battery properties, productivity, and safety. Therefore, the microporous polyolefin film needs to have appropriately balanced permeability, mechanical characteristics, dimensional stability, shutdown characteristics, melting characteristics, and the like. Here, the term “balanced” means that optimizing one of these properties does not significantly degrade another property.

  As is well known, separators with a relatively low shutdown temperature and a relatively high melting temperature are required to improve battery safety, particularly for batteries that are exposed to high temperatures during use. Uniform dimensional characteristics, such as film thickness, are essential for high performance films. A separator having high mechanical strength is desirable for a high-performance battery assembly and a battery having high-performance reliability. In order to improve the characteristics of the microporous polyolefin film, it has been proposed so far to optimize the material composition, molding and stretching conditions, heat treatment conditions, and the like.

  In general, microporous polyolefin membranes are substantially composed of polyethylene (i.e., this material is composed solely of polyethylene without significant inclusion of other materials) and has a relatively low melting temperature. have. Therefore, in order to raise the melting temperature, a microporous polyolefin film made from a polymer solution in which polyethylene and polypropylene resins are mixed, and a multiporous microporous polyolefin film having a polyethylene layer and a polypropylene layer have been proposed. Yes. Using a pomer solution containing such a mixed resin, or producing a multilayer film with different polyolefin layers, produces a film with uniform dimensional characteristics such as film thickness. Making it difficult to do.

  US Patent No. 2,938,201 proposes an extrusion mold for forming a sheet having an adjustable bolt that can be extended and having an adjustable film thickness. The adjustment bolt can be finely adjusted by a heater that controls the length of each bolt between the attachment point in the mold body and the connection point of the mold blade.

  US Patent No. 3,920,365 uses a temperature sensor and a heating element incorporated in the mold to control the thickness distribution of the film by selectively heat-controlling a pair of separated mold lip parts. Propose to do. By partially controlling the temperature change, the local viscosity of the molten polymer material and the local mass flow rate are increased or decreased to maintain the film thickness distribution within an acceptable range.

  In US Patent No. 4,124,342, in order to achieve the required mold gap distribution, that is, the required film thickness distribution, the film thickness is automatically calculated using an algorithm that calculates the rotation speed of each adjusting bolt. Systems have been proposed for automatic control. As can be easily understood, one problem with this system is that it assumes that the response of each of the mold adjustment bolts is all the same.

  US Patent No. 4,409,160 proposes a method for controlling the thickness of an extruded and biaxially stretched film product. In this method, the thickness thickness deviation (deviation) is automatically controlled. It has become. In this method, the correlation between the position along the width direction of the film-like sheet and the position of the adjustment bolt of the extrusion die is obtained, and before the film-like sheet is first stretched in the lateral direction, the film-like sheet is obtained. The plate thickness profile of the film is kept within an allowable range, and then stretched in the transverse direction, and then the plate thickness of the film is measured. Then, if the deviation (deviation) of the plate thickness is outside the allowable range, the thickness is corrected by sending a signal corresponding to the deviation (deviation) of the film thickness to the corresponding adjustment bolt of the mold. I have to.

  In US Patent No. 5,045,264, a composite film composed of one or more second materials embedded in a matrix material on one or both sides of a film, comprising a matrix material and a second material Methods and apparatus have been proposed for producing composite films that are made. The proposed device uses bolts to press the hinged mold lip against the opposite mold lip, thereby creating a gap defined by the two mold lips. Can be narrowed.

  Japanese utility model JP U3048972 proposes an extrusion die for reducing the divergence of the molten polymer flow in the manifold of the extrusion die. In the proposed extrusion mold design, two manifolds are provided to form two slit streams. Molten polymer is fed to the first inlet at the end of the first manifold and the second inlet at the end of the second manifold located opposite the first inlet. ing. The two slit flows are merged inside the mold. It has been theorized that the flow distribution within the mold can be made uniform by preventing the molten polymer flow from diverging in the manifold. Thereby, the uniformity of the plate | board thickness in the horizontal direction of a film or a sheet | seat can be improved.

  JP7-216118A in Japan discloses a battery separator formed of a porous film comprising at least two microporous layers having different polyethylene contents and comprising polyethylene and polypropylene as essential constituent elements. Yes. The polyethylene content is 0 to 20% by weight for one microporous layer, 21 to 60% by weight for the other microporous layer, and 2 to 40% by weight for the entire film. The battery separator has a relatively high shutdown start temperature and mechanical strength.

  In WO 2004/089627, composed of two or more layers, the polypropylene content in at least one surface layer is 50% or more by mass, 95% or more, or less, and the polyethylene content in the entire film is by mass, A microporous polyolefin membrane made from polyethylene and polypropylene, from 50% to 95%, is disclosed.

  WO 2005/113657 discloses a conventional microporous polyolefin film having shutdown characteristics, melting characteristics, dimensional stability, and high-temperature strength characteristics. This membrane is manufactured using a polyolefin composition comprising (a) a composition comprising low molecular weight polyethylene and high molecular weight polyethylene and (b) polypropylene. This microporous polyolefin film is manufactured by a so-called “wet process”.

Here the prior art as mentioned despite has the advantage, from the port Rimmer solution, an extrusion die capable of producing microporous polyolefin film, it needs still strong for high-quality film or sheet.

The invention disclosed herein relates to an extrusion mold for producing an extruded material made of a thermoplastic resin material such as a polymer and a diluent. The extrusion mold includes a mold outlet (for example, a slot provided) for taking out the extruded material.
The mold outlet is provided in, for example, the first mold lip part, the second mold lip part, and the first mold lip part, and the mixture of the polymer and the diluent is extruded from the mold outlet. includes a plurality of cantilevered adjustment member extending perpendicularly to the direction, each of the plurality of cantilevered adjusting member is the at the end opposite to the first die lip Drive means for driving the adjustment member by moving the mixture parallel to the direction in which the mixture is pushed out from the mold outlet , and the adjustment member is located at the first mold lip portion and the adjustment member connecting portion. By rotating about the axis in the width direction of the mixture extruded from the outlet, the extrusion gap at the mold outlet is adjusted by utilizing the principle of leverage .

In another aspect, a process for manufacturing an extruded material is provided. This process
Mixing at least one polyolefin with a solvent or diluent to prepare a polyolefin solution;
Extruding the polyolefin solution through an extrusion mold to form an extruded material, the extrusion mold comprising:
(1) A mold outlet for taking out the extruded thermoplastic resin material, a mold outlet having a first mold lip portion and a second mold lip portion;
(2) A plurality of cantilever-shaped adjustment members extending vertically from the first mold lip portion, each of which includes an adjustment member having a driving means.

  In one form, the extrusion mold includes a manifold having a supply inlet for receiving a mixture of polymer and diluent (eg, a polyolefin solution) and a pressure manifold in communication with the mold outlet.

  As another form, the manifold is a flat manifold, and may be a coat hanger manifold, a tail fin manifold, or a T-type manifold.

  As yet another form, the flat manifold is a coat hanger manifold, and the supply side inlet is disposed at the tip of the flat manifold.

  In yet another form, the extrusion mold accepts a first inlet of the mixture, and a supply-side inlet communicating with a supply-side distributor that diverts the polymer and diluent mixture into the first and second parts. A crossflow manifold comprising a first crossflow manifold portion communicating with the mold outlet and a second crossflow manifold portion receiving the second portion of the mixture and communicating with the mold outlet.

  The shape memory properties of polyolefins have been found to be a factor in maintaining the uniformity of the lateral thickness of the film or sheet exiting the extrusion die as a film or sheet. It has been observed that this shape memory effect also occurs in extruded materials consisting of a mixture of polyolefin and diluent. This was surprising because it was believed that the presence of the diluent would at least mitigate (even if it never disappears) the shape memory effect produced in the extruded material. Reducing the amount of polymer (compared to molten polymer) is expected to reduce the degree of polymer chain entanglement and improve rheological properties, thus mitigating the shape memory effect in polymer solutions. It was considered a thing.

  One part of the present invention is based on the new finding that when extruding a polymer and diluent mixture, the phenomenon of the shape memory effect affects the design of the extrusion mold manifold. Thus, in the embodiment disclosed herein, the crossflow manifold is a flow of sufficient length to reduce or eliminate the shape memory effect of the extruded thermoplastic material. A road is provided.

Furthermore, in another form disclosed herein, in order to further reduce variations in the thickness of the extruded material, each of the drive means is provided with individual lip bolts, and the mold outlet in the area adjacent to each adjustment member. The width can be changed effectively.

The above, or other advantages, features, and characteristics of the extrusion mold disclosed herein, and effective application methods and / or methods of use thereof, in particular, will be described in detail below. It will become clear by referring to the figures attached here.

FIG. 1 shows an exploded perspective view of an extrusion mold equipped with a cross-flow manifold system for producing a film or sheet of a thermoplastic resin material. FIG. 2 shows a part of an exploded perspective view of an extrusion mold provided with the cross flow manifold system shown in FIG. 1, and shows a pair of end face plates arranged in the mold. FIG. 3 shows an outline of an extrusion mold for producing a film or sheet of a thermoplastic resin material, and shows individual flow paths of the thermoplastic resin material. FIG. 4 shows a side view of an extrusion mold provided with a coat hanger-like manifold for producing a film or sheet of a thermoplastic resin material. FIG. 5 shows a perspective view of an extrusion mold for producing a film or sheet of a thermoplastic resin material, and shows an adjustment system of a cantilever-shaped mold lip portion. FIG. 6 shows a front view of a mold exit of an extrusion mold for producing a film or sheet of a thermoplastic resin material, and shows an adjustment system of a cantilever-shaped mold lip portion. It is. FIG. 7 is a perspective view of an extrusion mold for producing a film or sheet of a thermoplastic resin material, and shows a cantilever-shaped mold lip adjustment system having an external drive means. It is shown. FIG. 8A shows a simplified adjustment system of a cantilever-shaped mold lip portion provided with external driving means. FIG. 8B shows a simplified adjustment system for a cantilever-shaped mold lip portion provided with external driving means.

  Hereinafter, a description will be given with reference to FIGS. 1-8B. In these drawings, the same parts are denoted by the same reference numerals.

  First, FIG. 1-3 shows an extrusion die 10 for producing a film or sheet of a thermoplastic material. The extrusion die 10 is provided with a die outlet 12 having a slot cut, and a melt flow of the thermoplastic resin material is extruded as a film or a sheet through the die outlet 12. . In one form, the extrusion mold 10 is provided with a first mold part 14, a second mold part 16, and a third mold part 18, and further the first mold part. 14, a cross flow manifold 20 is provided that is disposed across a plurality of passages formed in the second mold part 16 and the third mold part 18. As can also be seen from the figure, the machine of the crossflow manifold 20 by using an extrusion mold 10 having a first mold part 14, a second mold part 16, and a third mold part 18. Processing and cleaning can be performed easily.

  As shown in detail in FIG. 1, the cross-flow manifold 20 has a supply-side inlet 22 and a supply-side distributor 24 for supplying polymer to a plurality of passages of the cross-flow manifold 20 communicating with the mold outlet 12. Is provided. This mold outlet can also be a mold outlet with a slot cut. During operation, a polymer solution (eg, a solution consisting of a polymer such as polyolefin and a diluent) F is distributed into a first feed stream S1 and a second feed stream S2. Then, the first supply flow S1 flows to the first cross flow manifold portion 26, and the second supply flow S2 flows to the second cross flow manifold portion 28. When polyolefin is selected as the polymer used to supply, the polymer solution refers to the polyolefin solution.

  The first mold portion 14 is provided with a first side surface 30, a second side surface 32, a first end surface 34, and a second end surface 36, and these surfaces have the cross flow manifold 20 Each part is provided. The second mold portion 16 is provided with an inner side surface 38, the third mold portion 18 is provided with an inner side surface 40, and each portion of the cross flow manifold 20 is provided on these surfaces. In addition, as can be assumed from FIG. 2, the first end face plate 42 and the second end face plate 44 are also provided with respective portions of the cross flow manifold 20.

  In one form, the first cross-flow manifold portion 26 includes a first plane 50 formed between the first side 30 of the first mold portion 14 and the inner side 38 of the second mold portion 16. Formed between the first passage 26a with the first shaft disposed therein, the first end face 34 of the first mold portion 14 and the first end face plate 42 (see FIG. 2). A second passage 26b with a second axis disposed in the second plane 52, a second side 32 of the first mold part 14 and an inner side 40 of the third mold part 18. And a third passage 26c having a third shaft disposed in a third plane 54 formed therebetween. As can be assumed from FIG. 1, the flow of the polymer solution is the third side formed between the second side 32 of the first mold part 14 and the inner side 40 of the third mold part 18. It flows through a pressure manifold 26d having a fourth axis disposed in the flat surface 54 so as to cross directly downward from the third passage 26c.

  Similarly, the second crossflow manifold portion 28 is within a third plane 54 formed between the second side 32 of the first mold portion 14 and the inner side 40 of the third mold portion 18. A first passage 28a having a first shaft disposed therein, a fourth passage formed between the second end face 36 of the first mold part 14 and the second end face plate 44 (see FIG. 2). Between the second passage 28b with a second axis disposed in the plane 56 of the first mold portion 14, the first side surface 30 of the first mold portion 14 and the inner side surface 38 of the second mold portion 16. And a third passage 28c having a third axis disposed in the formed first plane 50. As can be assumed from FIG. 1, the flow of the polymer solution flows so as to traverse downward directly from the third passage 28c. And a fourth shaft disposed in a first plane 50 formed between the first side face 30 of the first mold part 14 and the inner side face 38 of the second mold part 16. It flows through the pressure manifold 28d.

  In one form, each of the first cross-flow manifold portion 26 of the cross-flow manifold 20 and the second cross-flow manifold portion 28 of the cross-flow manifold 20 includes pressure manifolds 26e and 28e respectively communicating with the mold outlets. .

  As shown in the figure, in one embodiment, the first plane and the third plane, and the second plane and the fourth plane are arranged substantially in parallel. As used herein, “substantially parallel” means that the surfaces facing each other (that is, the first plane and the third plane, and the second plane and the fourth plane) are extrusion molds. This means that there is no crossing inside the outer contour.

  As described below, when forming microporous membrane films and sheets from polyolefin solutions, the surprising properties of these materials are inherent to shape memory similar to those observed when extruding molten polymers. Show properties. Other films and sheets formed from other polymers other than polyolefin also exhibit such characteristics. As is known in the art, shape memory plastics have two phases: a thermoplastic phase and a freezing phase. The initial shape is memorized in the freezing phase and has the shape memory effect of returning from its shape to its original shape even if the plastic is deformed to a temporary shape. As is well known, the polymer chain of the polymer has an ideal three-dimensional shape (Gaussian coil) in solution in the molten state or in the unperturbed state. For example, when the polymer is deformed by an external force such as a shear flow, the polymer shape is relaxed by expanding the polymer in the axial direction of the polymer, and the ideal Gaussian coil state is restored. This relaxation time is strongly dependent on the number of entanglements. Therefore, the longer the relaxation time is required, the higher the molecular weight of the polymer and the higher the polymer concentration in the solution.

  When a film or sheet is extruded from an extrusion mold, the shape memory characteristics of the polyolefin are one factor for maintaining a uniform thickness in the width direction of the film or sheet. And manifold designs have been found to be affected by this phenomenon. In one form, each of the crossflow manifold portion 26 and the crossflow manifold portion 28 of the crossflow manifold 20 is sufficiently long to substantially eliminate the shape memory characteristics of the thermoplastic material. It has the flow path which has.

  In another form, each of the crossflow manifold portion 26 and the crossflow manifold portion 28 of the crossflow manifold 20 traverses the extrusion mold 10 over a length that is at least twice the width of the extrusion mold 10. The flow path is provided.

  In another form shown in FIG. 4, another manifold design approach is incorporated. The extrusion mold 100 is provided with a mold outlet 112 provided with a slot, through which the melt flow formed into a layer of thermoplastic resin material is extruded as a film or a sheet (extrusion material). Is done. The extrusion die 100 also includes a flat manifold, which may be in the form of a coat hanger-like manifold 116 as shown, a tail fin-like manifold, or a T-type manifold. It may be in the form. As shown in the figure, the coat hanger-like manifold 116 includes a supply side injection port 118 at the front end 120 and a pressure manifold at an outlet 122 communicating with a mold outlet 112 provided with a slot. In one embodiment, the manifold 116 has an inclination (taper angle) so as to have a dimension longer than the lateral width of the mold 100 at a position intersecting with the supply side inlet. This sloped portion is aligned with the rheological properties of the polymer solution to ensure that the extruded material spans the entire width of the mold (i.e., TD (width direction)) to obtain thickness uniformity in the width direction (TD). ) It can be set to have a linear, quadratic, or other shape slope so as to be uniformly dispersed. The material may be supplied, for example, from the direction perpendicular to the manifold 116 to the tip portion 120, or from above the tip portion 120 to the tip portion 120. Or you may make it flow into the front-end | tip part 120 from another convenient direction.

  Next, referring to FIG. 5-7, the mold outlet 12 provided with the slot of the extrusion mold 10 may include a first mold lip portion 46 and a second mold lip portion 48. The first mold lip portion 46 includes a plurality of cantilever-shaped adjustment members 60 extending vertically from the first mold lip portion 46. As can be assumed from the drawing, the plurality of cantilever-shaped adjusting members 60 are formed so as to be able to rotate around an axis 66. Each of the plurality of cantilever-shaped adjusting members 60 includes a driving means 62. Mold heaters shown as 160, 180 can be attached to the mold end plates 42, 44 (shown as end plates 42).

  As shown in FIG. 7, each driving means 62 includes an individual lip bolt 64 so that the width of the mold outlet 12 provided with a slot in a region adjacent to each adjustment member can be changed. Each lip bolt 64 is threaded over the base plate 68 to the bolt tip 72. An adjustment pad 74 is disposed at the tip position 76 of each of the plurality of cantilever-like adjustment members 60 so as to come into contact with the bolt tip 72.

  Conveniently, the cantilever-shaped mold lip adjustment system disclosed herein has a function that allows the width of the mold gap to be locally and finely adjusted. By this function, the variation in the lateral direction of the thickness of the film or sheet can be remarkably reduced, and an extremely high quality film or sheet can be provided. For example, in a conventional mold lip adjustment system, lip bolts are typically arranged at intervals of 36 mm along the lateral direction (width direction) of the mold outlet. The pattern (thickness) in the lateral direction (width direction) of the film can be adjusted at intervals of about 180 mm. As can be understood from the above, it has been extremely difficult to finely adjust the thickness of the film in such a conventional mold lip adjustment system.

  In the cantilever-shaped mold lip adjustment system disclosed herein, the distance between the lip bolts is reduced to about 12 mm, which corresponds to a product width of about 60 mm. As can be seen from the figure, in the conventional design, if the gap between the lip bolts is simply shortened, the lip bolt needs to be thinned accordingly, and as a result, the rigidity of the lip bolt is reduced. There has been a problem that the function of accurately adjusting the width of the gap is degraded.

Referring to FIGS. 8A and 8B, it can be seen that the cantilever-shaped mold lip adjustment system disclosed herein utilizes the “lever principle”. Such a large torsional moment can be generated even when the distance between the lip bolts 64 is narrow. Control force of the lip portion of the die, ing in sufficient by changing the vertical component of the force in response to torsional moments. Further, the deformation of the first mold lip 46 due to the pressure from the inside of the extrusion mold 10 does not occur. Eventually, the stress generated at the connection between the base plate 68 of the main frame and the first mold lip 46 is reduced compared to other designs. In a related embodiment not shown, one adjusting bolt is used instead of the two bolts (64) shown in FIG. Optionally, one or two retaining bolts are used through the cantilevered portion 60 to attach to a convenient surface that the adjustment bolt (lip bolt) 64 supports. Alternatively, the retaining bolt can be used to attach the pivotable capture means to the cantilever 60. Such means makes it possible to adjust the screw of the adjusting bolt 64, and prevents the screw of the adjusting bolt 64 from rotating and loosening from the base plate due to an accident caused by undesirable vibrations.

It was found that the thickness of the film or sheet can be controlled very well by operating the cantilever-shaped mold lip adjustment system disclosed herein (the thickness variation in the lateral direction of the film or sheet is About ± 0.5 μm ). Furthermore, in the cantilever-shaped mold lip adjustment system disclosed here, it was confirmed that the thickness of the film can be adjusted at intervals of 50 mm.

  Even if heat is dissipated from around the first mold lip 46 and the second mold lip 48, this problem can be solved by using an insulating material.

  As already described, the extrusion mold disclosed herein is useful when forming a microporous film or sheet. These films and sheets are used particularly in the severe environment of battery separators. The extrusion mold described here focused on a mold for producing a single layer film or sheet, but can be easily understood by those skilled in the art, so a multi-layer coextrusion mold is used. Providing a mold is also included within the scope of the invention disclosed herein. Thus, the multilayer film described below is manufactured using a coextrusion mold, or a single layer mold of the type described above to produce a single layer film or sheet, and further using conventional techniques. A multilayer film can be produced by laminating another layer on the single layer.

  In one form, the multi-layer, microporous membrane is composed of two layers. The first layer (e.g., membrane skin layer, outer layer, upper layer) is made of the material of the first microporous layer, and the second layer (e.g., membrane bottom layer, lower layer, core layer) is And made of the material of the second microporous layer. For example, when viewed from above the axis approximately perpendicular to the lateral and longitudinal (mechanical) directions of the membrane, the membrane can see a flat upper layer and the flat bottom layer of the membrane is hidden behind the upper layer and cannot be seen. .

  As another form, in the case of a multi-layered microporous film having three or more layers, the outer layer (or surface layer or skin layer) is made of the material of the first microporous layer. The at least one core side layer or intermediate layer is made of the material of the second microporous layer. A related form is a multi-layer, microporous polyolefin film, in a two-layer film, the first layer is made of the material of the first microporous layer, and the second layer is the second layer. The material of the microporous layer. Further, as a related form, in the case of a multi-layered, microporous polyolefin film comprising three or more layers, the outer layer is made of the material of the first microporous layer, and at least One intermediate layer is made of the material of the second microporous layer. Such membranes are described in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389. And by quoting these publications here, these publications form a part of this specification.

The starting materials useful for the production of the aforementioned film or sheet are described below. Suitable polymers, solvents and their amounts are described, for example, in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389. As will be appreciated by those skilled in the art, the choice of starting material is not critical as long as a manifold system utilizing the principles of extrusion molds and crossflow manifolds is used. In one form, the material of the first and second microporous layers includes polyethylene. In one form, the material of the first microporous layer includes a first polyethylene (PE-1) having an Mw value of about 1 × 10 ⁶ or less or a second having an Mw value of at least about 1 × 10 ⁶ . Of polyethylene (UHMWPE-1). In one form, the material of the first microporous layer includes first polypropylene (PP-1). In one form, the material of the first microporous layer is (1) polyethylene (PE), (2) ultra high molecular weight polyethylene (UHMWPE), (3) PE-1 and PP-1, (4) PE- 1, composed of either UHMWPE-1 or PP-1.

(2) and (4) In one embodiment, UHMWPE preferably has an Mw value in the range of about 1 x 10 ⁶ to about 15 x 10 ⁶ , or in the range of about 1 x 10 ⁶ to about 5 x 10 ⁶ More desirable are those having an Mw value of about 1 x 10 ⁶ to about 3 x 10 ⁶ . In order to obtain a microporous layer having a hybrid structure as described in WO2008 / 016174, UHMWPE-1 is contained in an amount of about 1% by weight or more based on the total amount of PE-1 and UHMWPE-1. It is desirable that it is present, or it is more desirable that it is contained in an amount of about 15% by weight to about 40% by weight. In one embodiment of the above (3) and (4), PP-1 may be at least either a homopolymer or a copolymer, and about 25% by weight or less based on the total amount of the material of the first microporous layer. The content of is desirable. In one form, the Mw value of the polyolefin in the material of the first microporous layer may be about 1 × 10 ⁶ or less to obtain a microporous layer having a hybrid structure as defined later. It may range from about 1 × 10 ⁵ to about 3 × 10 ⁶ , or from about 2 × 10 ⁵ to about 3 × 10 ⁶ . In one form, PE-1 preferably has an Mw value in the range of about 1 x 10 ⁴ to about 5 x 10 ⁵ , or an Mw value in the range of about 2 x 10 ⁵ to about 4 x 10 ^5. What it has is further desirable. It may be one or more of high density polyethylene, medium density polyethylene, branched low density polyethylene, or linear low density polyethylene, and may be at least either a homopolymer or a copolymer.

In one form, the material of the second microporous layer is (1) a fourth polyethylene (UHMWPE-2) having an Mw value of at least about 1 × 10 ⁶ , and (2) an Mw value of 1 × 10 ⁶ or less. The third polyethylene and UHMWPE-2, as well as the fourth polyethylene, wherein the fourth polyethylene comprises at least about 8% by weight based on the total weight of the third polyethylene and the fourth polyethylene; 3) Consists of one of UHMWPE-2 and PP-2, (4) PE-2, UHMWPE-2, and PP-2. In the forms of (2), (3), and (4) described above, UHMWPE-2 is used to produce a microporous polyolefin film that is a relatively strong multilayer material. And at least about 8%, alternatively at least about 20%, alternatively at least about 25% by weight relative to the total amount of PP-2. In the above forms (3) and (4), PP-2 may be at least either a homopolymer or a copolymer, and is 25% by weight or less based on the total amount of materials of the second microporous layer, Alternatively, an amount in the range of about 2% to about 15% by weight, or in the range of about 3% to about 10% by weight can be included. In one embodiment, preferred PE-2 can be the same as PE-1, but can also be selected independently. In one embodiment, preferred UHMWPE-2 can be the same as UHMWPE-1, but can also be selected independently.

  In one form, a process for producing a two-layer microporous polyolefin membrane is provided, in which an extrusion mold and manifold system of the type disclosed herein is used. In another form, the microporous polyolefin membrane has at least a three-layer construction and is manufactured using an extrusion mold and manifold system of the type disclosed herein. The production of a microporous polyolefin film will be described mainly as a film having a two-layer structure and a three-layer structure.

  In one embodiment, the microporous polyolefin film having a three-layer structure is provided between the first and third microporous layers forming the outer layer of the microporous polyolefin film and the first and third layers (optional). And a second layer (core layer) disposed in contact with the substrate. In another form, the first layer and the third layer are made from a first polyolefin solution and the second layer (core layer) is made from a second polyolefin solution.

In one embodiment, a method for producing a microporous polyolefin film having a multilayer structure is provided. The manufacturing method is
(1) To prepare a first mixture of polyolefin and diluent (first polyolefin solution), a first polyolefin composition and at least one diluent (e.g., a film-forming solvent) (e.g., melted) Mixing (by blending);
(2) To prepare a second mixture of polyolefin and diluent (second polyolefin solution), a second polyolefin composition and at least a second diluent (for example, a second film-forming solvent) Mixing, and
(3) extruding first and second polyolefin solutions from at least one mold of the type disclosed herein to form a multi-layer extruded material;
(4) optionally cooling the multi-layered extruded material to form a cooled extruded material;
(5) removing at least a portion of the film-forming solvent from the extruded or cooled extruded material to form a multilayered film;
(6) Preferably, the method includes a step of removing at least a volatile substance from the multi-layered film.
The step (7) of stretching the optional extruded material and the step (8) of treating the optional extruded material with a heated solvent are performed between steps (4) and (5) if necessary. After step (6), optionally stretching (9) a multi-layered microporous film, optionally heat-treating the multi-layered microporous film (10), and optionally ionizing radiation The step (11) of crosslinking by, the step (12) of hydrophilic treatment as an option, etc. can be carried out.

  The first polyolefin composition is composed of a polyolefin resin as described above and is mixed with a suitable film forming solvent, for example, by dry mixing or melt blending, to create a first polyolefin solution. As an option, for example, as disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389, the first polyolefin solution includes one or more antioxidants, silicate fine powder (pore forming material), etc. The additive may also be included.

  The first and second diluents can be solvents that are in a liquid state at room temperature. Suitable diluents are disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389.

In one form, the resin or the like used to produce the first polyolefin composition is melt blended in an extruder or blender using two screw members. For example, conventionally used extruders (or blenders and blender-extruders), such as an extruder using two screw members, use a resin or the like to form the first polyolefin composition. Can be used when mixing. The film-forming solvent can be added to the polyolefin composition (or the resin used to create the polyolefin composition) at a convenient point in the process. For example, in one form, the first polyolefin composition and the first film-forming solvent are melt blended and the film-forming solvent is
(1) Before starting melt blending,
(2) During melt blending of the first polyolefin composition, or
(3) Can be added to the polyolefin composition (or its components) at any stage after melt blending. And this is, for example, melt blended or partially melt blended in a region located downstream of the extruder used to melt blend the polyolefin composition or in a second extruder. The first film-forming solvent is supplied to the polyolefin composition.

  Suitable methods for combining the polymer and diluent are disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389.

  The amount of the first polyolefin composition in the first polyolefin solution is not critical. In one form, the amount of the first polyolefin composition in the first polyolefin solution can range from about 1 wt% to about 75 wt%, for example, about 1 wt%, based on the weight of the polyolefin solution. It may be in the range of 20 wt% to about 70 wt%. The remaining part of the polyolefin solution is solvent. For example, the polyolefin solution may include from about 30% to about 80% by weight solvent (or diluent) based on the weight of the polyolefin solution.

  The second polyolefin solution can be prepared by the same method used in preparing the first polyolefin solution. For example, the second polyolefin solution can be prepared by melt blending the second polyolefin composition and the second film-forming solvent.

  The amount of the second polyolefin composition in the second polyolefin solution is not critical. In one form, the amount of the second polyolefin composition in the second polyolefin solution can range from about 1 wt% to about 75 wt%, based on the weight of the second polyolefin solution, For example, it may be in the range of about 20 wt% to about 70 wt%. The remaining part of the polyolefin solution is solvent. For example, the polyolefin solution may include from about 30% to about 80% by weight solvent (or diluent) based on the weight of the polyolefin solution.

  Conveniently, an extrusion die of the type disclosed herein is used to form an extrusion that can be coextruded or laminated. As one form, the extrusion metal mold | die which can be arrange | positioned in parallel or arrange | positioned together is used in order to form a some extrusion material. The first and second sheet molds are connected to the first and second extruders, respectively. Here, the first extruder is provided with the first polyolefin solution, and the second extruder is provided with the second polyolefin solution. While not critical, when laminating, it is generally easy to do laminating when the extruded first and second polyolefin solutions are still near the extrusion temperature.

  In another form, first, second, and third molds are connected to the first, second, and third extruders. Here, the first and third molds are provided with the first polyolefin solution, and the second mold is provided with the second polyolefin solution. In this form, the laminated extruded material is formed to constitute two outer layers made of the extruded first polyolefin solution and one intermediate layer made of the extruded second polyolefin solution.

  In yet another form, first, second, and third molds are connected to the first, second, and third extruders. Here, the second mold includes the first polyolefin solution, and the first and third molds include the second polyolefin solution. In this form, the laminated extruded material is formed to constitute two outer layers composed of the extruded second polyolefin solution and one intermediate layer composed of the extruded first polyolefin solution.

  In general, the gap size of the mold is not particularly critical. For example, an extrusion mold of the type disclosed herein can have a mold gap dimension between about 0.1 mm and about 5 mm. Mold temperature and extrusion rate are also non-critical parameters. For example, during extrusion, the mold temperature can be heated to be in the range of about 140 ° C to about 250 ° C. The extrusion rate can be, for example, in the range of about 0.2 m / min to about 15 m / min. The thickness of the layer of the extruded material having a laminated structure can be set independently. For example, the sheet finally obtained can have a relatively thick skin layer or surface layer compared to the thickness of the intermediate layer of the extruded material having a laminated structure.

  Optionally, the multi-layer extrusion can be cooled. The cooling rate and cooling temperature are not particularly critical. Suitable cooling methods are disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389.

  In one form, at least the first and second film-forming solvents are removed from the multilayered extruded material to form a multilayered microporous film. For example, a cleaning solvent is used for this purpose. Suitable solvent (diluent) removal methods are disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389.

  In one form, at least volatile material (eg, cleaning solvent) left on the film is removed. Suitable methods for removing volatile substances are disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389.

  Prior to the step for removing the film-forming solvent, the extruded material can be stretched to obtain an extruded material with directionality.

  Methods for drawing extruded or cooled extrudates are disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389.

  Although not required, the extruded material can be treated with a hot solvent, as disclosed in WO2000 / 20493.

  As one form, the microporous film can be stretched in at least one axial direction after removing at least the diluent. The selected stretching method is not critical and conventional stretching methods such as the tenter method can be used. As described herein, when the extruded material is stretched, stretching a microporous polyolefin film in a dry state is called dry stretching, re-stretching, or dry orientation. Suitable stretching methods are disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389.

  The amount of stretching when stretching is not a critical issue. For example, the amount of stretch of the microporous membrane can range from about 1.1 to about 2.5, or from about 1.1 to about 2.0, in at least one in-plane direction. Biaxial stretching is also possible, and in this case, the amount of stretching need not be symmetrical (the same for each axis).

  In one form, the microporous film can be heat treated and / or annealed. Microporous membranes can be cross-linked if necessary (eg, by irradiation with ionizing radiation such as a-rays [3-rays, 7-rays, electron beams, etc.]). Further, a hydrophilic treatment can be applied to the microporous membrane. (That is, this hydrophilic treatment makes the microporous olefin membrane more hydrophilic. [Eg, monomer affinity treatment, surfactant treatment, corona discharge treatment, etc.]) Heat treatment of membrane, annealing, Suitable methods for processing such as crosslinking are disclosed in WO2008 / 016174, US2008 / 0057388, and US2008 / 0057389.

  In addition, the microporous film manufacturing method disclosed in PCT International Publication No. WO2008 / 016174 (multilayer film) and No. WO2007 / 132942 (single layer film) can also be used.

  All patents, test procedures, and other documents cited herein, including the document on which priority is claimed, are hereby incorporated by reference in their entirety to the extent they are not contradictory. And this should be allowed in all jurisdictions.

  Although the embodiments disclosed herein have been described as specific, it is possible for those skilled in the art to make various improvements without departing from the technical idea of the present invention. It is self-evident and it can be easily implemented. Therefore, the scope of claims (claims) attached to the present specification is not limited to the examples and descriptions described in the present specification. It should be construed as including all the patentable novel technical features described therein, and all such technical features shall be deemed equivalent by those skilled in the art to which this invention belongs. Should be handled.

  In this specification, when an upper limit numerical value and a lower limit numerical value are described, it is intended to include a range from the lower limit to the upper limit.

Claims (10)

An extrusion mold for producing an extruded material of a thermoplastic resin material from a polymer solution,
(1) A mold outlet through which a mixture of a polymer and a diluent is extruded, the mold outlet including a first mold lip portion and a second mold lip portion;
(2) A plurality of cantilever-shaped adjustment members provided on the first mold lip portion and extending perpendicularly to the direction in which the mixture is pushed out from the mold outlet, each of which is adjusted member has a driving means for driving the adjusting member by said mixture at an end opposite said first die lip is moved parallel to the direction that is extruded from the die outlet, the adjustment The member is located at the connecting portion between the first mold lip portion and the adjustment member, and rotates about the axis in the width direction of the mixture extruded from the mold outlet, so that the lever principle is achieved. A plurality of cantilever-shaped adjusting members that adjust the extrusion gap at the mold outlet by using ,
(3) An extrusion mold comprising a supply side inlet for receiving a mixture of the polymer and the diluent, and a manifold having a pressure manifold communicating with the mold outlet. 2. The extrusion mold according to claim 1, wherein each of the driving means includes an individual lip bolt, and each lip bolt can change a width of a mold outlet provided with a slot. Extrusion mold. 3. The extrusion mold according to claim 2, further comprising a base plate, wherein each of the individual lip bolts is threaded through the base plate to the tip of the bolt, and the tip of the bolt Is an extrusion mold characterized in that it is in contact with an adjustment pad attached to the tip of each adjustment member in the form of a cantilever. An extrusion mold according to any one of claims 1 to 3,
An extrusion die, wherein the manifold is a flat manifold. An extrusion mold according to claim 4, wherein
The extrusion mold according to claim 1, wherein the flat manifold is a coat hanger manifold, a tail fin manifold, or a T-shaped manifold. An extrusion mold according to claim 5, wherein
The extrusion mold according to claim 1, wherein the flat manifold is a coat hanger manifold, and the supply-side inlet is disposed at a front end of the coat hanger manifold. An extrusion die according to any one of claims 1 to 6,
(4) a supply-side inlet that communicates with a supply-side distributor that divides the mixture into a first part and a second part;
(5) Cross flow manifold, the cross flow manifold
(a) a first crossflow manifold portion in communication with the mold outlet and receiving a first portion of the mixture;
(b) An extrusion die characterized by further comprising a crossflow manifold formed from a second crossflow manifold portion communicating with the die outlet and receiving a second portion of the mixture. An extrusion mold for producing an extruded material of a thermoplastic resin material from a polymer solution,
(1) A mold outlet through which a mixture of a polymer and a diluent is extruded, the mold outlet including a first mold lip portion and a second mold lip portion;
(2) A plurality of cantilever-shaped adjustment members provided on the first mold lip portion and extending perpendicularly to the direction in which the mixture is pushed out from the mold outlet, each of which is adjusted The member has a driving means at an end opposite to the first mold lip portion, and the adjustment member is located at a connection portion between the first mold lip portion and the adjustment member. A plurality of cantilever-shaped adjustment members provided so as to rotate around an axis in the width direction of the mixture extruded from the mold outlet;
(3) a supply-side inlet for receiving the polymer and diluent mixture, and a manifold having a pressure manifold communicating with the mold outlet;
(4) a supply-side inlet that communicates with a supply-side distributor that divides the mixture into a first part and a second part;
(5) Cross flow manifold, the cross flow manifold
(a) a first crossflow manifold portion in communication with the mold outlet and receiving a first portion of the mixture;
(b) a second crossflow manifold portion communicating with the mold outlet and receiving a second portion of the mixture, and a crossflow manifold comprising:
Each of the first crossflow manifold portion of the crossflow manifold and the second crossflow manifold portion of the crossflow manifold includes a flow path that traverses at least twice the length of the extrusion mold. An extrusion mold characterized by that. The extrusion die according to claim 7 or 8,
The first cross-flow manifold portion includes a first passage having a first shaft disposed in a first plane of the extrusion mold and a second passage disposed in a second plane of the extrusion mold. A third passage that is in communication with the first passage and a third shaft that is disposed in the third plane of the extrusion die and that is in communication with the second passage. And a third passage communicating with the mold outlet provided with the slot,
The second cross-flow manifold portion includes a first passage having a first shaft disposed in a third plane of the extrusion mold and a second passage disposed in a fourth plane of the extrusion mold. A third passage that is in communication with the first passage, a second passage that is in communication with the first passage, and a third shaft that is disposed in the first plane of the extrusion mold. An extrusion mold characterized by comprising: An extrusion die according to claim 9,
An extrusion die, wherein the first plane and the third plane, and the second plane and the fourth plane are arranged substantially in parallel.

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