Spinneret for making hollow fiber membranes

Abstract

The present invention relates to a spinneret for making a hollow fiber membrane. The spinneret includes a body having an inlet surface, an outlet surface, and a bore that runs from the inlet surface to the outlet surface. An inlet to the bore is defined through the inlet surface and an outlet to the bore is defined through the outlet surface. The outlet includes an arc shaped die defined by at least one arc shaped slit. The at least one arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD), a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95.

Description

Attorney Docket No. 3192-114-01PCTSPINNERET FOR MAKING HOLLOW FIBER MEMBRANESBACKGROUND OF THE INVENTION

[0001] This application claims the benefit under 35 U.S.C. §119(e) of prior U.S. Provisional Patent Application No. 63 / 730,517, filed December 11, 2024, which is incorporated in its entirety by reference herein.

[0002] The present invention relates to spinnerets for making hollow fiber membranes that can be used for dialyzers or other filtration systems, as well as methods for manufacturing hollow fiber membranes using the spinnerets.

[0003] Spinnerets are specialized devices for the production of hollow fiber membranes, which are integral to various filtration and separation applications, such as water treatment, gas separation, and medical uses. Examples of spinnerets are shown in U.S. Patent Nos. 3,691,068, 4,906,375, and 4,051,300.

[0004] Spinnerets are designed with precision to extrude polymer solutions or melts through tiny holes, creating fibers with a hollow, tubular structure. Typically made from durable materials like stainless steel to endure high temperatures and corrosive environments, spinnerets play a pivotal role in defining the physical characteristics of the resulting membranes. Their design allows for the formation of a consistent and uniform hollow structure, which is critical for the performance and efficiency of the membranes in their respective applications. The development and refinement of spinneret technology has been fundamental to advancing the capabilities of hollow fiber membranes, making them more effective and versatile in addressing diverse filtration and separation needs.

[0005] Manufacturing a hollow fiber membrane with a high void lumen fraction and a thin wall is desirable. Hollow fiber membranes with a high void lumen fraction and thin walls offer significant advantages in various applications, particularly in dialysis filtration, separation, and bioprocessing.Attorney Docket No. 3192-114-01PCT

[0006] Accordingly, a need exists for improved spinnerets that can be used to make hollow fiber membranes having a higher void lumen fraction and / or thinner walls.SUMMARY OF THE PRESENT INVENTION

[0007] A feature of the present invention is to provide a spinneret for making hollow fiber membranes.

[0008] Another feature of the present invention is to provide a spinneret for making hollow fiber membranes having a high void lumen fraction and / or relatively thin walls.

[0009] Another feature of the present invention is to provide a spinneret for making hollow fiber membranes having at least one arc shaped die.

[0010] A further feature of the present invention is to provide a method of making a hollow fiber membrane using a spinneret having at least one arc shaped die.

[0011] A further feature is to provide a spinneret for making hollow fiber membranes by melt extrusion processes.

[0012] Still a further feature of the present invention is to provide a multi piece spinneret having a reduced slit width of an arc shaped die.

[0013] Additional features and advantages of the present invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the description and appended claims.

[0014] To achieve these and other advantages, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention relates to a spinneret for making a hollow fiber membrane. The spinneret includes an arc shaped die. The arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD) that satisfies the equation of ID / OD that is up to 0.95, such as an OD of from 1.95 mm to 6.6Attorney Docket No. 3192-114-01PCT mm, a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95.

[0015] The present invention also relates to a method of forming a hollow fiber membrane using a spinneret. The spinneret includes an arc shaped die. The arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD) that satisfies the equation of ID / OD that is up to 0.95, such as an OD of from 1.95 mm to 6.6 mm, a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95. The method includes passing at least one thermoplastic polymer through the spinneret to obtain melt-spun fibers, and then optionally stretching the melt-spun fibers.

[0016] The present invention, in addition, relates to a spinneret for making a hollow fiber membrane. The spinneret includes a body having an inlet surface, an outlet surface, and a bore that runs from the inlet surface to the outlet surface, wherein an inlet to the bore is defined through the inlet surface, and an outlet to the bore is defined through the outlet surface, the outlet including an arc shaped die defined by at least one arc shaped slit. The at least one arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD) that satisfies the equation of ID / OD that is up to 0.95, such as an OD of from 1.95 mm to 6.6 mm, a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95.

[0017] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a further explanation of the present invention, as claimed.

[0018] The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate various features of the present invention and, together with the description, serve to explain the principles of the present invention.Attorney Docket No. 3192-114-01PCTBRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings represent various aspects and / or design features of the present invention. Similar referencing identifiers in different figures can refer to similar features unless indicated otherwise. The drawings are not necessarily to scale.

[0020] FIG. l is a cross-section view of a melt spinner and spinneret of an embodiment of the present invention, illustrating a process of melt spinning an exemplary hollow fiber membrane.

[0021] FIG. 2 is a diagram showing a spinneret die design of an embodiment of the present invention.

[0022] FIG. 3 is a diagram showing another spinneret die design of an embodiment of the present invention.

[0023] FIG. 4 is a diagram showing another spinneret die design of an embodiment of the present invention.

[0024] FIG. 5 is a diagram showing another spinneret die design of an embodiment of the present invention.

[0025] FIG. 6 is a diagram showing another spinneret die design of an embodiment of the present invention.

[0026] FIG. 7A is a side view of a spinneret of an embodiment of the present invention.

[0027] FIG. 7B is a bottom view of the spinneret of FIG. 7A.

[0028] FIG. 7C is a top view of the spinneret of FIG. 7 A.

[0029] FIG. 8 is a bottom view of a spinneret of an embodiment of the present invention.

[0030] FIG. 9A is a perspective view of a spinneret of an embodiment of the present invention.

[0031] FIG. 9B is a detail section view of the spinneret showing circle B of FIG. 9A.

[0032] FIG. 9C is an exploded perspective view of the spinneret of FIG. 9 A.Attorney Docket No. 3192-114-01PCT

[0033] FIG. 9D is a cross-sectional view of the spinneret of FIG. 9A.

[0034] FIG. 10A is a detail perspective partial cutaway view of a spinneret of an embodiment of the present invention.

[0035] FIG. 10B is a top view and a perspective view of a plate of the spinneret of FIG. 10A.

[0036] FIG. 10C is a bottom perspective view of the spinneret of FIG. 10 A.

[0037] FIG. 10D is a bottom view of the spinneret of FIG. 10A, illustrating an insert removed from a body.

[0038] FIG. 10E is a top view of the spinneret of FIG. 10A.DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0039] The present invention relates to a spinneret used to make hollow fiber membranes and to methods of making the hollow fiber membranes using the spinneret of the present invention. As described herein, the spinneret can have multiple designs and optional features.

[0040] The spinneret for making a hollow fiber membrane comprises, consists essentially of, consists of, or includes an arc shaped die, wherein the arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD) that satisfies the equation of ID / OD that is up to 0.95, such as an OD of from 1.95 mm to 6.6 mm, a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95.

[0041] The spinneret can include a body having an inlet surface, an outlet surface, and a bore that runs from the inlet surface to the outlet surface, an inlet to the bore that is defined through the inlet surface, and an outlet from the bore that is defined through the outlet surface. The outlet includes the arc shaped die defined by at least one arc shaped slit. The inlet surface and the outlet surface can be opposing surfaces of the spinneret. Alternatively, the inlet surface and the outlet surface can be adjacent surfaces of the spinneret or the same surface of the spinneret.Attorney Docket No. 3192-114-01PCT

[0042] The spinneret can be part of or releasably attached to a melt spinner for producing melt-spun fibers. The melt spinner can include a container or hopper for containing a polymeric material. The polymeric material can be dried in a drying device and then can be made molten in a melting device, such as a screw conveyor. In the spinneret, the molten polymer material is pressed through the at least one arc shaped slit. By use of press and metering pumps, the melt polymer is pressed through the at least one arc shaped slit and is withdrawn in the form of filaments and respectively hollow fibers. After exiting from the spinneret, the filaments are cooled and can be collected for storage or further processing, such as being wound onto drums or placed in vessels.

[0043] The spinneret includes at least one bore or capillary having an inlet and an outlet. The outlet can be considered a nozzle. The outlet of the bore comprises an arc shaped die defined by at least one arc shaped slit when viewed in cross section. The spinneret can include a plurality of bores, each of them adapted to extrude hollow fibers. The respective bores can be identical in design, and can each include the arc shaped die so that a plurality of identical hollow fibers can be extruded from the spinneret. For example, the spinneret can include 1 to 10,000 openings or bores that each include a respective arc shaped die.

[0044] The at least one arc shaped slit can be considered one or more opening segments of the arc shaped die having an arcuate shape, one or more opening segments that curve concentrically, one or more opening segments that curve concentrically around a longitudinal axis of the spinneret, one or more opening segments that have a semi-circular shape, one or more opening segments that have a C-shape, or the like.

[0045] The at least one arc shaped slit can have a longitudinal side and a transverse side. A gap of the at least one arc shaped slit is in between the transverse sides of the at least one arc shaped slit.Attorney Docket No. 3192-114-01PCT

[0046] The arc shaped die includes an inner diameter (ID), an outer diameter (OD), and a slit width. The at least one arc shaped slit that defines the arc shaped die is a concentric opening defined between an inner concentric wall and an outer concentric wall. The ID is defined herein as a diameter of the inner concentric wall. The OD is defined herein as a diameter of the outer concentric wall. The slit width is defined herein as a distance between the inner concentric wall and the outer concentric wall. The ID, OD, and / or the slit width dimensions can be considered average dimensions for the arc shaped die.

[0047] The ID of the arc shaped die can be from 1.75 mm to 6 mm, from 1.8 mm to 6 mm, from 2.0 mm to 6 mm, from 2.2 mm to 6 mm, from 2.4 mm to 6 mm, from 2.6 mm to 6 mm, from 2.8 mm to 6 mm, from 3 mm to 6 mm, from 3.2 mm to 6 mm, from 3.4 mm to 6 mm, from 3.6 mm to 6 mm, from 3.8 mm to 6 mm, from 4 mm to 6 mm, from 4.2 mm to 6 mm, from 4.4 mm to 6 mm, from 4.6 mm to 6 mm, from 4.8 mm to 6 mm, from 5 mm to 6 mm, from 5.2 mm to 6 mm, from 5.4 mm to 6 mm, from 5.6 mm to 6 mm, from 5.8 mm to 6 mm, from 1.75 mm to 5.9 mm, from 1.75 mm to 5.8 mm, from 1.75 mm to 5.5 mm, from 1.8 to 5 mm, from 2 mm to 4 mm, or any range based upon any two values described herein.

[0048] The OD of the arc shaped die can be from 1.9 mm to 12 mm, from 2.0 mm to 12 mm, from 2.1 mm to 12 mm, from 2.1 mm to 11.8 mm, from 2.3 mm to 11.6 mm, from 2.5 mm to 11.4 mm, from 2.7 mm to 11.2 mm, from 2.9 mm to 11.0 mm, from 3.1 mm to 10.8 mm, from 3.3 mm to 10.6 mm, from 3.5 mm to 10.4 mm, from 3.7 mm to 10.2 mm, from 3.9 mm to 10.0 mm, from 4.1 mm to 9.8 mm, from 4.3 mm to 9.6 mm, from 4.5 mm to 9.4 mm, from 4.7 mm to 9.2 mm, from 4.9 mm to 9.0 mm, from 5.1 mm to 8.8 mm, from 5.3 mm to 8.6 mm, from 5.5 mm to 8.4 mm, from 5.7 mm to 8.2 mm, from 5.9 mm to 8.0 mm, from 6.1 mm to 7.8 mm, from 6.3 mm to 7.6 mm, from 6.5 mm to 7.4 mm, from 6.7 mm to 7.2 mm, from 6.9 mm to 7.1 mm, from 2 mm to 10 mm, from 4 mm to 8 mm, from 1.95 mm to 6.6 mm, from 2 mm to 6 mm, from 3 mm to 5 mm, or any range based upon any two values described herein.Attorney Docket No. 3192-114-01PCT

[0049] The slit width can be 0.1 or greater. For example, the slit width can be from 0.1 mm to 0.8 mm, from 0.2 mm to 0.7 mm, from 0.3 mm to 0.6 mm, from 0.4 mm to 0.5 mm, from 0.1 mm to 0.3 mm, from 0.1 mm to 0.2 mm or any range based upon any two values described herein.

[0050] The arc shaped die of the spinneret can further be characterized by an ID / OD, which is the inner diameter divided by the outer diameter. The ID / OD can be up to 0.95. For example, the ID / OD can be from 0.5 mm to 0.95 mm, from 0.55 mm to 0.9 mm, from 0.6 mm to 0.85 mm, from 0.65 mm to 0.8 mm, from 0.7 mm to 0.75 mm, from 0.7 to 0.95, from 0.8 to 0.95, from 0.9 to 0.95, or any range based upon any two values described herein.

[0051] As an example, the arc shaped die of the spinneret can include a slit width from 0.1 mm up to 0.3 mm and an ID / OD can be from 0.7 to 0.95. A low slit width in combination with a high ID / OD allow the spinneret to form a hollow fiber membrane with a higher void lumen fraction and thinner walls, as compared to conventional hollow fiber membranes. When hollow fiber membranes are used as filters for hemodialysis, the hollow fiber membranes having a high void lumen and thin walls provide an improved mass transfer or clearance, while at the same time, allowing blood to flow through the fibers. The formation of fiber membranes with such parameters is not easily done with the use of any spinneret and presents many challenges in manufacturing such fiber membranes. Hollow fibers used in the textile industry preferably have a lower density and improved insulation, and thus a hollow fiber with a higher void lumen fraction and thinner walls may not be beneficial for such non-dialysis purposes. Thus, most hollow fibers used for the textile industry are either for lowering fiber density (i.e. lighter materials) or for insulation by taking advantage of low thermal transferring through air. These type of fibers and their use mean that they do not require a high void lumen fraction, large ID, nor thin walls. For non-dialysis membrane applications, there is no need for a large fiber ID. In contrast, this is the requirement for hemodialysis. Combining both the need for thin wallAttorney Docket No. 3192-114-01PCT(better mass transfer or clearance) and the need for large enough ID to run blood inside the fibers leads to the high void lumen fraction and thin walls.

[0052] As mentioned above, at least one arc shaped slit can have a transverse side. A gap of the at least one arc shaped slit is in between the transverse sides of the at least one arc shaped slit. The gap distance, i.e., a distance between transverse sides of the at least one arc shaped slit, can be from 0.1 mm to 0.5 mm, from 0.12 mm to 0.48 mm, from 0.14 mm to 0.46 mm, from 0.16 mm to 0.44 mm, from 0.18 mm to 0.42 mm, from 0.2 mm to 0.4 mm, from 0.22 mm to 0.38 mm, from 0.24 mm to 0.36 mm, from 0.26 mm to 0.34 mm, from 0.28 mm to 0.32 mm, 0.1 mm to 0.3 mm, or any range based upon any two values described herein.

[0053] The arc shaped die can further include a gap / slit width, which is the gap size divided by the slit width. The gap / slit width can be from 0.7 to 2, from 0.8 to 1.9, from 0.9 to 1.8, from 1.0 to 1.7, from 1.1 to 1.6, from 1.2 to 1.5, from 1.3 to 1.4, or any range based upon any two values described herein.

[0054] The arc shaped die can further include a slit width / ID, which is the slit width divided by the inner diameter. The slit width / ID can be from 1 to 0.01, from 0.95 to 0.05, from 0.9 to 0.1, from 0.85 to 0.15, from 0.8 to 0.2, from 0.75 to 0.25, from 0.7 to 0.3, from 0.65 to 0.35, fromO.6 to 0.4, from 0.55 to 0.45, or any range based upon any two values described herein.

[0055] The arc shaped die can further include a slit width / OD, which is the slit width divided by the outer diameter. The slit width / OD can be from 0.008 to 0.8, from 0.02 to 0.75, from 0.03 to 0.7, from 0.04 to 0.65, from 0.05 to 0.6, from 0.06 to 0.55, from 0.07 to 0.5, from 0.08 to 0.45, from 0.09 to 0.4, from 0.1 to 0.35, from 0.12 to 0.3, from 0.14 to 0.25, from 0.16 to 0.2, or any range based upon any two values described herein.

[0056] The arc shaped die can further include an OD / slit width, which is the outer diameter divided by the slit width. The OD / slit width can be from 5 to 40, from 7 to 38, from 9 to 36,Attorney Docket No. 3192-114-01PCT from 11 to 34, from 13 to 32, from 15 to 30, from 17 to 28, from 19 to 26, from 21 to 24, from 22 to 23, or any range based upon any two values described herein.

[0057] The arc shaped die can further include an [ID / OD]2, which is the inner diameter divided by the outer diameter, which is then squared. The [ID / OD]2can be from 0.5 to 0.9, from 0.55 to 0.85, from 0.6 to 0.8, from 0.65 to 0.75, or any range based upon any two values described herein. (ID / OD)2represents the area of the hollow region to the overall area in the cross section of the fiber and hollow area, and can provide an understanding of “how void” the fiber can be, and can be viewed as the “void ratio”. For a circle, the area can be calculated based on the formula: pR2.

[0058] The arc shaped die can further include an ID / 2 / slit width, which is the inner diameter divided by 2 divided by the slit width. The ID / 2 / slit width can be from 6 to 20, from 7 to 19, from 8 to 18, from 9 to 17, from 10 to 16, from 11 to 15, from 12 to 14, or any range based upon any two values described herein.

[0059] The above-mentioned parameters and characterizations of the arc shaped die allow for the spinneret of the present invention to form hollow fiber membranes having a high void lumen fraction and / or a relatively thin wall. Hollow fiber membranes with a high void lumen fraction and thin walls offer significant advantages in various applications, particularly in filtration, separation, and bioprocessing. Specifically, the high void lumen fraction improves the flow of the liquid passing therethrough and the relatively thin walls improve upon the filtration of the liquid. The hollow fiber membranes formed by the spinneret of the present invention are especially useful when used as a filter for dialysis treatments.

[0060] The arc shaped die can include one or more arc shaped slits. For example, the arc shaped die can have one arc shaped slit, two arc shaped slits, three arc shaped slits, four arc shaped slits, five arc shaped slits, six arc shaped slits, seven arc shaped slits, eight arc shaped slits, nine arc shaped slits, ten arc shaped slits, or more arc shaped slits. Accordingly, the arcAttorney Docket No. 3192-114-01PCT shaped die can be formed of 1 arc to 10 arcs, 1 arc to 8 arcs, 1 arc to 6 arcs, 1 arc to 4 arcs, or 1 arc to 2 arcs.

[0061] The arc shaped die can include one or more gaps, depending on the number of arc shaped slits. For example, the arc shaped die can have one gap, two gaps, three gaps, four gaps, five gaps, six gaps, seven gaps, eight gaps, nine gaps, ten or more gaps.

[0062] The gaps can be uniformly spaced apart from each other. For instance, a two-gap arc can have a 180 degree spacing, a three gap arc can have 120 degree spacing, a four gap arc can have 90 degree spacing, a five gap arc can have 72 degree spacing and so on.

[0063] Generally, when two or more gaps are present, the gap size is the same or about the same (within 10% of each gap present).

[0064] The at least one arc shaped slit can have one or more levees extending from the transverse sides. Levees can project outward away from a longitudinal axis of the arc shaped die. The levees can aid in closing the gap to form the hollow fiber membrane when the polymer resin exits the spinneret. Specifically, when melted polymer resin exits the arc-shape slits, the side of the arc-shape polymer films merge together, i.e., the gap is closed, and thus the hollow fiber membranes are formed to have a tube shape.

[0065] The arc shaped slit can be an outlet of an arc shaped duct. The arc shaped duct can be formed from two separate pieces or can be cut from or otherwise manufactured into the spinneret. For example, the arc shape duct can be formed by wire electrical discharge machining, wateijet, laser cutting, 3-D printing using direct metal laser sintering, or the like.

[0066] A spinneret core or cylinder can project coaxially into and through the bore, forming the arc shaped duct, through which the extruded material is fed between the outer surface of the core and inner surface of the bore. As an option, the spinneret can be configured such that the outer diameter of the hollow fiber membrane is smaller than the outer diameter of the arc shapedAttorney Docket No. 3192-114-01PCT duct, and the inner diameter of the hollow fiber membrane is smaller than the inner diameter of the arc shaped duct.

[0067] As mentioned above, the spinneret can include more than one piece forming the arc shaped duct. For example, the spinneret includes a body having an inlet surface, an outlet surface, and a bore that runs from the inlet surface to the outlet surface. An inlet to the bore is defined through the inlet surface, and an outlet to the bore is defined through the outlet surface. An insert can be seated within the bore. The at least one arc shaped slit and arc shaped duct can be defined between an outer surface of the insert and an inner surface of the bore.

[0068] The bore defined through the body of the spinneret can include a wide portion and a narrow portion. The wide portion has a larger diameter than the narrow portion. The wide portion can begin at the inlet of the bore and extend to a central area within the bore. The narrow portion can begin at the central area within the bore and extend to the outlet of the bore. An annular ledge can be formed at the central area of the bore where the wide portion and the narrow portion meet.

[0069] As an option, the annular ledge can include a taper. The annular ledge can gradually taper from the wide portion to the narrow portion. As an option, a portion of the annular ledge can include the taper. For example, a first portion of the annular ledge can be orthogonal to an inner surface of the bore, and a second portion of the annular ledge can taper from the first portion of the annular ledge to the narrow portion of the bore, such that the bore gradually narrows from the first portion of the annular ledge to the narrow portion, forming a bore funnel portion. The bore funnel portion can define a frustoconical shape.

[0070] The insert can include a cylinder that fits within the bore. As an option, the insert includes a base and a cylinder extending from the base. The base can have a larger diameter than the cylinder. The base includes a flange surface adjacent to the cylinder and an inlet surface opposite the flange surface.Attorney Docket No. 3192-114-01PCT

[0071] The insert can be seated within the bore. The base can have a diameter such that the base precisely fits within the wide portion of the bore. The cylinder can fit within the narrow portion of the bore and can be co-axial with the bore. A gap is defined between an outer surface of the cylinder and the inner surface of the bore, forming the arc shaped duct and the arc shaped slit.

[0072] As an option, at least one opening is formed through the base of the insert from the inlet surface to the flange surface. The at least one opening can be an arc shaped opening. As an option, the at least one opening can be a plurality of openings. The plurality of openings can be circular openings in an annular arrangement. The insert can be inserted into the bore and the flange surface can rest against the annular ledge, while the cylinder rests within the narrow portion of the bore.

[0073] As mentioned above, the at least one arc shaped slit can be defined between an outer surface of the insert and an inner surface of the bore. Specifically, the at least one arc shaped slit can be defined between an outer surface of the cylinder and an inner surface of the narrow portion of the bore. The one opening or plurality of openings of the base of the insert fluidly connect the inlet of the bore with the at least one arc shaped slit.

[0074] As an option, the insert can include an insert funnel portion. The insert funnel portion includes a taper from the base to the cylinder of the insert. The insert funnel portion gradually widens from the base to the cylinder and can have a frustoconical shape. When the insert is disposed within the bore, the insert funnel portion can align with the bore funnel portion, which forms a funnel from the one opening or plurality of openings of the base to the at least one arc shaped duct.

[0075] The insert can be removable from the body, and can be seated within the body to form the spinneret. As an option, the insert can be welded or otherwise attached within the bore of the body to form the spinneret.Attorney Docket No. 3192-114-01PCT

[0076] As an option, the insert can include at least one protrusion radially extending from the outer surface of the cylinder. The at least one protrusion protrudes from the outer surface of the cylinder and can touch the inner surface of the narrow portion of the bore, and thus can extend across the entire, or substantially the entire slit width. The at least one protrusion forms the gap of the at least one arc shaped slit.

[0077] As an option, the insert can include a plurality of protrusions such that the at least one arc shaped slit is a plurality of arc shaped slits. The protrusions can be uniformly spaced apart from each other. For instance, an insert with two protrusions can have a 180 degree spacing, an insert with three protrusions can have 120 degree spacing, an insert with four protrusions can have 90 degree spacing, an insert with five protrusions can have 72 degree spacing and so on.

[0078] As an option, the multi-piece spinneret can utilize a plate. The spinneret includes a body including an inlet surface, an outlet surface, and a bore that runs from the inlet surface to the outlet surface. An outlet of the bore is defined at the outlet surface and an inlet of the bore is defined at the inlet surface. The plate can be disposed at the outlet of the bore and can include the arc shaped slit. The thickness of the plate, and thus the thickness of the arc shaped die can be from about 0.5 mm to about 10 mm, such as from 1 mm to 10 mm, or from 2 mm to 10 mm, or from 3 mm to 10 mm, or from 4 mm to 10 mm, or from 5 mm to 10 mm, or from 0.75 mm to 10 mm, or from 6 mm to 10 mm.

[0079] The multi-piece spinneret that utilizes the plate can further include an insert. The insert can include a duct running through a longitudinal axis of the insert. The body can further include a lip extending radially inward at the outlet of the bore. The lip can be a circumferential lip. The plate can include a width and a length greater than a diameter of the opening formed by the circumferential lip. Thus, the plate can be disposed inside the bore and rest against an inner surface of the circumferential lip. The insert fits within the bore and secures the plate inAttorney Docket No. 3192-114-01PCT place against the circumferential lip. The duct of the insert can direct melt polymer to the arc shaped slit of the plate.

[0080] As an option, the bore can include a threaded inner surface, while the insert can include a threaded outer surface. The threaded outer surface of the insert can be screwed into the threaded inner surface of the bore, such that the insert presses against the plate, securing the plate with the arc shaped die at the outlet of the bore. As an option the insert can be welded within the bore or secured therein by other mechanical fasteners.

[0081] The multi -piece spinnerets described herein are particularly useful for the spinnerets having relatively small slit widths. For example, machining (e.g., laser cutting) a spinneret to have a slit width of 0.1 mm to 0.3 mm along a spinneret’s entire depth can be difficult and time consuming. The multi-piece spinneret of the present invention having slits defined between an inner surface of a bore of a body and an outer wall of an insert eliminates the need for laser cutting. Additionally, the multi-piece spinneret having a plate with a reduced thickness allows the slits with a reduced slit width to be laser cut through the thin plate with relative ease.

[0082] The body of the spinneret can further include a sidewall. As an option, at least a portion of the sidewall can be threaded. For example, an upper portion of the body can be threaded and lower portion of the body can be unthreaded. The upper portion of the sidewall that is threaded can include a smaller diameter than the lower portion that is unthreaded. Such a configuration allows for the spinneret to be releasably attached to a melt spinner so that spinnerets can be interchanged with the melt spinner to manufacture different sizes and types of hollow fiber membranes.

[0083] FIG. 1 is a cross-section view of a melt spinner 100 and a spinneret 102 of an embodiment of the present invention, illustrating a process of melt spinning an exemplary hollow fiber membrane 112. Melt spinner 100 includes a hopper 104 that dispenses polymer granules to an extruder 106. Extruder 106 includes an inlet 107 to a barrel 108 and a screwAttorney Docket No. 3192-114-01PCT conveyor 110 within barrel 108. Melt spinner 100 can utilize a single screw extruder or a twin- screw extruder. Screw conveyor 110 is rotated and the polymer granules are heated within the extruder 106 to a form a melt polymer. The melt polymer is forced through spinneret 102 that is attached to an outlet 109 of barrel 108. The melt polymer is extruded through spinneret 102 to form hollow fiber membrane 112.

[0084] FIG. 2 is a diagram showing a spinneret die design of an embodiment of the present invention. Spinneret 202 includes an arc shaped slit 203. Arc shaped slit 203 includes an inner diameter (ID) 204, an outer diameter (OD) 206, and a slit width 208. Slit width 208 is a distance between ID 204 and OD 206. ID 204 and OD 206 can include any of the diameters described herein, and slit width 208 can include any of the distances described herein. For example, ID 204 can be from 1.75 mm to 6 mm, OD can be from 1.95 mm to 6.6 mm, slit width 208 can be from 0.1 mm to 0.3 mm, and ID / OD can be up to 0.95. Arc shaped slit 203 can include transverse sides 210 and longitudinal sides 212. A gap 214 of arc shaped slit 203 can be disposed between transverse sides 210. Gap 214 can be any of the distances described herein, such as from 0.1 mm to 0.3 mm.

[0085] FIG. 3 is a diagram showing another spinneret die design of an embodiment of the present invention. FIG. 3 shows a portion of an arc shaped slit 303 having a slit width 308, transverse sides 310, and longitudinal sides 312. A gap 314 of arc shaped slit 303 is disposed between transverse sides 310. Levees 316 extend from arc shaped slit 303 at transverse sides 310 of arc shaped slit 303 and project outward in a direction away from a longitudinal axis of the arc shaped die. Arc shaped slit 303 includes a corner 317 that is at about a 90-degree angle where levees 316 meet arc shaped slit 303. Length 319 of levees 316 can be from 2x to 5x of the slit width 308.

[0086] FIG. 4 is a diagram showing another spinneret die design of an embodiment of the present invention. Spinneret 400 includes an arc shaped die 402 including three arc shapedAttorney Docket No. 3192-114-01PCT slits 404 and three gaps 414. Gaps 414 are evenly spaced apart and thus have a 120-degree spacing.

[0087] FIG. 5 is a diagram showing another spinneret die design of an embodiment of the present invention. Spinneret 500 includes an arc shaped die 502 including six arc shaped slits 504 and six gaps 514. Gaps 514 are evenly spaced apart and thus have a 60-degree spacing.

[0088] FIG. 6 is a diagram showing another spinneret die design of an embodiment of the present invention. Spinneret 600 includes an arc shaped die 602 including ten arc shaped slits 604 and ten gaps 614. Gaps 614 are evenly spaced apart and thus have a 36-degree spacing.

[0089] FIG. 7A is a side view of a spinneret 700 of an embodiment of the present invention. FIG. 7B is a bottom view of spinneret 700 of FIG. 7A. FIG. 7C is a top view of spinneret 700 of FIG. 7A. Spinneret 700 includes a body 702 having an inlet surface 704, an outlet surface 706, and a bore 708 that runs from inlet surface 704 to outlet surface 706. An inlet 710 to bore 708 is defined through inlet surface 704, and an outlet 712 to bore 708 is defined through outlet surface 706.

[0090] Outlet 712 includes an arc shaped die 714 defined by three arc shaped slits 716. Three gaps 717 are disposed in between arc shaped slits 716. Arc shaped die 714 and arc shaped slits 716 can include the dimensions as described herein. A plurality of openings 722 within bore 708 fluidly connect inlet 710 of bore 708 to arc shaped slits 716.

[0091] FIG. 8 is a top view of a spinneret 800 of an embodiment of the present invention. Spinneret 800 includes similar structure to spinneret 700 shown in FIGS. 7A-C, and includes a body 802, an outlet surface 806, an arc shaped die 814, and arc shaped slits 816. As can be seen, arc shaped die 814 of spinneret 800 is different than arc shape die 714 of spinneret 700 of FIGS. 7A-C, as arc shaped die 814 includes twelve arc shaped slits 816 and twelve gaps 817.

[0092] FIG. 9A is a perspective view of a spinneret 900 of an embodiment of the present invention. FIG. 9B is a detail section view of spinneret 900 showing circle B of FIG. 9A. FIG. 9CAttorney Docket No. 3192-114-01PCT is an exploded perspective view of spinneret 900 of FIG. 9A. FIG. 9D is a cross-sectional view of spinneret 900 of FIG. 9 A. Referring to FIGS. 9A-9D, spinneret 900 includes a body 902 having an inlet surface 904, an outlet surface 906, and a bore 908 that runs from inlet surface 904 to outlet surface 906. An inlet 910 to bore 908 is defined through inlet surface 904, and an outlet 912 to bore 908 is defined through outlet surface 906.

[0093] Bore 908 can include an inner surface 909 having a wide portion 922 and a narrow portion 924. An annular ledge 926 is formed at the central area of bore 908 where wide portion 922 and narrow portion 924 meet. Annular ledge 926 includes a taper 928, forming a bore funnel portion. The bore funnel portion can define a frustoconical shape. Body 902 can further include a threaded portion 918 and an unthreaded portion 920. Threaded portion 918 allows spinneret 900 to be releasably attachable to a melt spinner, such as melt spinner 100 shown in FIG. 1.

[0094] Spinneret 900 further includes an insert 930. Insert 930 includes an outer surface 933, a base 934, and a cylinder 932. Base 934 includes a flange surface 936 adjacent to cylinder 932 and an inlet surface 938 opposite flange surface 936. A plurality of openings 940 are formed through base 934 from inlet surface 938 to flange surface 936. Plurality of openings 940 are in an annular arrangement. Insert 930 further includes an insert funnel portion having a taper 942 from base 934 to the cylinder 932. The insert funnel portion gradually widens from base 934 to cylinder 932 and has a frustoconical shape. Insert 930 further includes three protrusions 944 radially extending from outer surface 933 of cylinder 932.

[0095] Insert 930 fits within bore 908. Base 934 has a diameter such that base 934 precisely fits within wide portion 922 of bore 908. Flange surface 936 rests against annular ledge 926 when engaged. Cylinder 932 fits within narrow portion 924 of bore 908 and is co-axial with bore 908. A space is defined between outer surface 933 of cylinder 932 and inner surface 909 of bore 908, forming one or more arc shaped ducts 917 and one or more arc shaped slits 916 of an arc shaped die 914. The insert funnel portion can align with the bore funnel portion, which forms a funnelAttorney Docket No. 3192-114-01PCT from plurality of openings 940 to the at least one arc shaped duct 917. Three protrusions 944 touch inner surface 909 at narrow portion 924 of bore 908, and thus can extend across the entire slit width. Three protrusions 944 form three gaps between three arc shaped slits 916. Three protrusions 944 are spaced apart evenly and have 120 degree spacing. As part of the present invention, different inserts can be utilized in the bore, with the alternative inserts having a different number of gaps and / or forming a different slit width and / or affecting other parameters as described herein. The inserts can be interchangeable.

[0096] Flange surface 936 is generally in contact with ledge 926 so that an outlet surface of insert 930 and outlet surface 906 of the body 902 are at the same level. The co-occupied length of insert 930 and bore 908 is preferred in order to produce arc shaped die 914 that includes a symmetrical arc shaped duct 917 and arc shaped slit 916. The length of arc shaped duct 917 can be from about 2 mm to about 10 mm.

[0097] FIG. 10A is a detail perspective partial cutaway view of a spinneret 1000 of an embodiment of the present invention. FIG. 10B is a top view and a perspective view of a plate 1015 shown of spinneret 1000 of FIG. 10 A. FIG. 10C is a bottom perspective view of spinneret 1000 of FIG. 10A. FIG. 10D is a bottom view of spinneret 1000 of FIG. 10A, illustrating an insert 1030 removed from a body 1002. FIG. 10E is a top view of spinneret 1000 of FIG. 10A.

[0098] Referring to FIGS 10A-10E, spinneret 1000 includes a body 1002 including an inlet surface 1004, an outlet surface 1006, and a bore 1008 that runs from inlet surface 1004 to the outlet surface 1006. An inlet 1010 to bore 1008 is defined through inlet surface 1004, and an outlet 1012 to bore 1008 is defined through outlet surface 1006. Body 1002 further includes a circumferential lip 1029 extending radially inward at outlet 1012 of bore 1008. Body 1002 can further include a threaded portion 1018 and an unthreaded portion 1020. Threaded portion 1018 allows spinneret 1000 to be releasably attachable to a melt spinner, such as melt spinner 100 shown in FIG. 1.Attorney Docket No. 3192-114-01PCT

[0099] Spinneret 1000 further includes an insert 1030 and plate 1015. Plate 1015 includes an arc shaped die 1014 formed by three arc shaped slits 1016. Insert 1030 includes a duct 1032 running through a longitudinal axis of insert 1030. Plate 1015 includes a width and a length greater than a diameter of an opening formed by circumferential lip 1029. Plate 1015 is disposed inside bore 1008 and rests against an inner surface of circumferential lip 1029. Insert 1030 fits within bore 1008 and secures plate 1015 in place against circumferential lip 1029. Insert 1030 includes male threads 1034 that secure to female threads 1009 of bore 1008. Duct 1032 of insert 1030 guides the melt polymer to arc shaped slits 1016 of plate 1015. As part of the present invention, different plates can be utilized with spinneret 1000. Insert 1030 is removable from bore 1008 and plate 1015 can be removed and replaced with an alternate plate having differing specifications. For example, the alternate plate can have a different number of gaps and / or have a different slit width and / or have any of the different parameters as described herein. Plates 1015 can be mass produced and are interchangeable within spinneret 1000.

[0100] The present invention further relates to methods to form a hollow fiber membrane using a spinneret of the present invention. The method can comprise, consist essentially of, consists of, or include preparing at least one membrane forming polymer (e.g., a thermoplastic polymer) to form a melted polymer, and melt spinning the melted polymer using the spinneret of the present invention to obtain melt-spun fibers, and then stretching the melt-spun fibers.

[0101] The hollow fiber membrane having a lumenal compartment can be prepared from a molten (or melted) resin comprising at least one membrane forming polymer, which can be or include at least one hydrophobic polymer. The hydrophobic polymer can be at least one polyolefin, such as a combination of polypropylene (PP) and polyethylene (PE). The hydrophobic polymer can be a thermoplastic polyurethane (TPU). Other examples include, but are not limited to, polysulfone (PSF), polyethersulfone (PES), poly aryl sulfone (PAS), and / orAttorney Docket No. 3192-114-01PCT polyarylethersulfone (PAES), and optionally at least one hydrophilic polymer (e.g., PVP), or the polymer can be or include one or more polymethyl methacrylate polymers (PMMA), polyvinylidene fluoride (PVDF), and / or or any copolymer thereof, and may exclude a hydrophilic polymer.

[0102] The method of making the hollow fiber membrane of the present invention can further include the step of rinsing and / or conditioning the fiber membrane after fiber formation which optionally can remove at least a portion of any leachables as defined herein. The rinsing step can be primarily to remove at least a portion of the additional additive(s), if used.

[0103] Generally, the starting components are fed into an extruder, such as a twin-screw extruder to form the melted polymer that can then be fed to the spinneret so as to form the hollow fiber membranes.

[0104] With respect to the extrusion step, the starting components can be introduced into the extruder as a pre-mixture, or one or more components can be added in sequence and / or at different ports of the extruder. The extruder can operate at the extruder manufacturer’s specifications.

[0105] The material entering the spinneret can have a viscosity that can be characterized by a melting flow index (MFI) (and sometimes referred to as MI or MFR) and is measured using the standard test: ASTM D1238 or ISO 1133 at a temperature of 190 °C or a temperature of 230 °C at 1 atm. The material entering the spinneret can have a MFI of from about 2 g / lOmin at 190 °C to about 150 g / lOmin at 190 °C, such as from about 2 g / lOmin at 190 °C to about 100 g / lOmin at 190 °C, or from about 2 g / lOmin at 190 °C to about 75 g / lOmin at 190 °C, or from about 2 g / lOmin at 190 °C to about 50 g / lOmin at 190 °C, or from about 2 g / lOmin at 190 °C to about 30 g / lOmin at 190 °C.

[0106] The material temperature achieved during extrusion can be from about 100 °C to about 400 °C, such as about 200 °C to about 400 °C.Attorney Docket No. 3192-114-01PCT

[0107] During extrusion, the apparent shear rate can range from 10 seconds'1to 10,000 seconds'1.

[0108] The melt spinner can utilize an extruder pump. The extruder pump can pump the melted polymer to the spinneret, and the extruder pump pressure can be from 10 psi to 3000 psi, such as from 1000 psi to 2000 psi.

[0109] The line speed of the fiber, for example, in the spinning process can be 10 meters per minute to 10,000 meters per minute, such as 1,000 meters per minute to 5,000 meters per minute.

[0110] The stretching that can be achieved of the melt-spun fiber can comprise, consist essentially of, consist of, or include utilizing a draw ratio of from 1.1 to 25 and / or a draw speed of 5% to 2000% or 5% to 1500% per minute. The draw ratio is determined by comparing the length of the fiber prior to drawing to the length of the same fiber after drawing. The draw speed % is the percent change of fiber length per minute (measuring at timeo and measuring at timeeosec and calculating the percent change in length).

[0111] The stretching step can apply a force of on the melt-spun fiber. The hollow fiber membrane extruded from the spinneret of the present invention can include pores or can be non-porous.

[0112] The stretching can comprise, consists of, or include a stretch of from 100% to 2000% (e.g., from 100% to 1500%, from 100% to 1000%, from 100% to 700%, from 100% to 500%, from 250% to 2000%, from 500% to 2000%) of the melt-spun fiber in an axial direction, wherein the percent is calculated based on the length prior to the stretching and the length after the stretching.

[0113] One particular stretching step can comprise or include 1) a cold drawing of less than 30 °C, such as 15 °C to 25 °C, and 2) a hot drawing that is at a hot drawing temperature that is 10 °C to 50 °C below the Tgor Tmof the at least one polymer, and 3) annealing at a temperatureAttorney Docket No. 3192-114-01PCT that is within 10 °C to 20 °C of the Tgof the at least one polymer or is 5 °C to 10 °C above the hot drawing temperature.

[0114] The cold drawing, hot drawing, and annealing can be achieved with the use of a chamber or temperature-controlled zone, such as an oven or refrigerator-type chamber. The desired temperature can be achieved with conventional temperature controlling equipment and thermostats and the like. Electricity, heaters, hot plates, cold plates, heated rollers, chilled rollers, and / or channels with temperature controlled mediums (such as heating and / or cooling jackets) can be utilized with the fiber(s) passing through the chamber or zone or being fed through such devices for a distance such as at least 10 mm, such as from 10 mm to 1000 mm or more to obtained the desired effect, namely, cold drawing, hot drawing, or annealing.

[0115] Another particular example of a stretching step can comprise or include 1) a hot drawing that is at a hot drawing temperature that is 50 °C to 150 °C or is at least 10 °C below the Tgof the highest Tgcomponent present in the melt-spun fiber (e.g., at least 20 °C below or at least 30 °C below the Tgof the highest Tgcomponent present in the melt-spun fiber) and 2) annealing at a temperature that is greater than the Tgof the melt-spun fiber (e.g., greater than 5 °C, or greater than 10 °C of the Tgof the melt-spun fiber).

[0116] The melted polymer is fed to the inlet of the bore of the spinneret. As an example, the melted polymer can pass through the plurality of openings of the insert, through the funnel, and forced into the arc shaped duct. The melted polymer can then be extruded through the shaped duct and out of the arc shaped slit to form the melt spun fibers.

[0117] Draft refers to exit speed of the fiber-like structure from the arc shaped slit of the spinneret as differing from (and usually greater than) the speed at which the fiber is drawn off. Draft can cause stretching of the fiber structure as it issues from the arc shaped die of the spinneret during the fiber formation in such a way that the fiber structure is stretched in the draft direction and for this reason can be permanently deformed. The speed of emergence of the spinningAttorney Docket No. 3192-114-01PCT composition from the spinneret and the drawing off speed of the fiber produced can be made generally the same to avoid spinning draft and reduce possible occurrence of fiber structure deformations or formation of constrictions of the fiber lumen and thinning out of the fiber wall. As an option, the pumping rate of the fiber can be slower than the draw rate from the spinneret, which causes a drawing of the fiber and reduces its diameter. This drawing or pulling can optionally be used to form the fiber.

[0118] The hollow fiber can be texturized in order to improve the exchange properties thereof. After this, the fiber so produced can be handled in a conventional manner, for example, by winding onto a bobbin or wheel, cutting the fibers to a desired length, and / or used in manufacture of dialyzers using the cut fiber in a conventional manner.

[0119] Upon exiting the spinneret, the formed hollow polymer fiber or hollow polymer fiber membrane may pass through or be guided into an air chamber which can also be considered an air gap. For purposes of the present invention, this air chamber can be a self-enclosed chamber or structure (or partially self-enclosed chamber) which has an entrance for the hollow fiber to enter and an exit for the hollow fiber to exit but otherwise, as an option, can be self-enclosed in order to optionally control the atmosphere within the air chamber, and optionally, the temperature within the air chamber. The air gap can be used to cool fibers to a lower temperature prior to stretching. For instance, the temperature of this air chamber can be from about 30°C to 60°C or other temperatures within or outside this range. This air chamber or air gap can also be considered by one of skill in the art to be the spinning shaft area.

[0120] As an option, a rinsing bath can be used. Generally, the size or distance between the exit point of the spinneret or arc shaped slit and the bath can be, for instance, from about 0 mm to about 1500 mm or more, such as from about 200 mm to about 1 meter, or from about 400 mm to about 12 meters, and this distance or gap can be totally within the air chamber if a self-enclosed chamber is used. As an example, the time that the hollow polymer fiber membrane spends in theAttorney Docket No. 3192-114-01PCT air chamber can be on the order of from about 1 second to about 240 seconds. As an option, the air chamber can have controlled humidity which can range from a relative humidity of 20% to over 99%.

[0121] As indicated, the hollow polymer fiber exiting the air chamber can optionally enter a bath or bath area. The bath comprises, consists essentially of, consists of, includes, or is an aqueous solution. The bath chamber can, in a similar manner as the air chamber, be optionally a self-enclosed area (or partially self-enclosed chamber) that has an entry point and an exit point for the hollow polymer fiber. For purposes of the present invention, the bath can be entirely an aqueous solution such as water. As an option, other components can be included in the aqueous bath such as one or more water-dispersible solvents or additives such as, but not limited to, one or more types of alcohols or polar aprotic solvents. As an option, the temperature of the bath can be controlled for instance to about 10°C to 80°C or from about 15°C to 25°C, or from about 60° to 70°C, or other temperatures. Generally, the bath or bath chamber can be of a size of from about 10 mm to about 1000 mm in length. As an option, the time that the hollow polymer fiber membrane is submerged (residence time) in the bath in the bath chamber can be on the order of from about 0.1 second to about 30 seconds or 1 or more hours (such as up to 5 hours).

[0122] The hollow polymer fiber membrane can then be passed into or guided into at least one drying chamber. As in the case with the other chambers, the drying chamber can be a selfenclosed area (or partially self-enclosed chamber) that can be atmospherically controlled independently of the other chambers and that has an entry point and an exit point for the hollow polymer fiber membrane. The temperature of the drying chamber can be, for instance, 80°C or higher, above 80°C, above 90°C, above 100°C, above 110°C, 120°C or higher, above 120°C, above 130°C, above 140°C, above 150°C, above 160°C, above 170°C, above 180°C, such as from about 80°C to 220°C, from 90°C to 220°C, from 120°C to 220°C, from about 130°C to 200°C, from about 140°C to 200°C, from about 185°C to 220°C, from about 150°C to about 220°C, orAttorney Docket No. 3192-114-01PCT from about 170°C to about 200°C or other temperatures. The residence time in the drying chamber, whether one drying chamber or multiple drying chambers, can be from about 0.5 second to about 1000 seconds. The size of the drying chamber(s) can be from about 100 mm to about 10,000 mm in length or longer. The total fiber length immersed in drying chamber(s) may be greater than 20,000 mm, such as from about 50,000 mm to about 100,000 mm. If more than one drying station or chamber is used, the chamber / station temperature used for drying can be the same or different for each chamber / station.

[0123] During the drying step, and / or during the act of drying of the hollow polymer fiber membrane, the surface temperature of the hollow polymer fiber can be 80°C or higher, above 80°C, above 90°C , above 100°C , above 110°C, 120°C or above, above 120°C, above 130°C, above 140°C, above 150°C, above 160°C, above 170°C, or even above 180°C, such from about 80°C to 220°C, 90°C to 220°C, or from about 120°C to about 220°C, or from about 130°C to about 220°C, or from about 140°C to about 200°C, or from about 150°C to about 190°C or other temperatures.

[0124] As an option, the step of drying can be accomplished in the absence of irradiating of the hollow polymer fiber membrane with microwaves, either high output (26 kW to 100 kW or more) or low output (e.g. 25 kW or less). Thus, as an option, no irradiation type driers (e.g., no microwave-irradiation type driers) are utilized during the drying step.

[0125] As an option, the step of drying can be accomplished in the absence of reduced pressure. Thus, as an option, no reduced pressure atmosphere or zone (e.g., 0.1 kPa to 22 kPa) is utilized during the drying step.

[0126] After exiting the drying chamber, the hollow polymer fiber, now dry or substantially dry, can be collected. The collecting of the hollow polymer fiber membrane can be done in any manner in which fibers are typically collected, such as, but not limited to, using a bobbin or a wheel. The fibers may be crimped before they are collected by a bobbin.Attorney Docket No. 3192-114-01PCT

[0127] In any of the methods of the present invention, the method can further include the step of collecting the hollow fiber membrane as a bundle of fibers or other collection of fibers and the method can further include inserting the bundle of fibers into a dialyzer module and potting the melt-spun fibers in the dialyzer module.

[0128] The method can further include enclosing the bundle of fibers or collection of fibers in a sealed package. The step can optionally or alternatively include autoclaving the sealed package to form a sterilized sealed package. Typically, the autoclaving is done by achieving a temperature of at least 121 °C for at least 10 or more minutes, such as 20 minutes or more. The sealed package can be a polymer package such as a food grade or medical grade packaging material such as polyethylene, polypropylene, or polyethylentherephtalate. The packaging material may be a layered material comprising a metal foil as one layer. The sealed package can be a vacuum sealed package.

[0129] The material that is introduced into the spinneret preferably contains low amounts of water or no water. For instance, the material that is introduced into the spinneret can contain 5 wt% water or less (based on the weight of the spin mass), such as 0.001 wt% to 5 wt%, 0.01 wt% to 4 wt%, 0.1 wt% to 4 wt%, 0.5 wt% to 3.5 wt%, 0.75 wt% to 3 wt%, 0.9 wt% to 1.7 wt%, or 0 wt%, and the like.

[0130] The hollow fiber membrane resulting from the spinneret of the present invention can be used for various applications in microfiltration, ultrafiltration, and nanofiltration, including water treatment, dialysis, gas separation, and applications in environmental sustainability, medical devices, and the energy industry, as well as for general thermal insulation in the textile industry and absorbance applications requiring a large surface area.

[0131] The present invention further relates to a method of conducting dialysis. The method comprising, consist essentially of, consists of, or includes utilizing the hollow fiber membrane of the present invention for blood purification. The membrane can be a bundle ofAttorney Docket No. 3192-114-01PCT fibers which is used in a dialysis procedure. For instance, the dialysis can be hemodialysis, hemodiafiltration, hemofiltration, single-pass dialysis, regenerable dialysate dialysis, or peritoneal dialysis. The details of conducting dialysis with a fiber membrane are known to those skilled in the art with the exception of using the hollow fiber membrane formed by the spinneret of the present invention. Various details of dialysis and methods and set-ups are described for instance in the Handbook of Dialysis, Third Edition by John T. Gaugirdas et al., incorporated in its entirety by reference herein.

[0132] The present invention further relates to a method to purify water or conducting water purification. The method comprising, consist essentially of, consists of, or includes utilizing the hollow fiber membrane of the present invention to purify at least in part the water or for water purification. The details of conducting water purification with a fiber membrane are known to those skilled in the art with the exception of using the hollow fiber membrane formed by the spinneret of the present invention.

[0133] The present invention includes the following aspects / embodiments / features in any order and / or in any combination:1. The present invention relates to a spinneret for making a hollow fiber membrane, the spinneret comprising: an arc shaped die, wherein the arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD) that satisfies the equation of ID / OD that is up to 0.95, a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95.2. The spinneret of any preceding or following embodiment / feature / aspect, wherein the ID is from 1.8 mm to 5 mm.3. The spinneret of any preceding or following embodiment / feature / aspect, wherein the ID is from 2 mm to 4 mm.Attorney Docket No. 3192-114-01PCT4. The spinneret of any preceding or following embodiment / feature / aspect, wherein the slit width is from 0.1 mm to 0.2 mm.5. The spinneret of any preceding or following embodiment / feature / aspect, wherein the ID / OD is from 0.7 to 0.95.6. The spinneret of any preceding or following embodiment / feature / aspect, wherein the ID / OD is from 0.8 to 0.95.7. The spinneret of any preceding or following embodiment / feature / aspect, wherein the ID / OD is from 0.9 to 0.95.8. The spinneret of any preceding or following embodiment / feature / aspect, wherein the OD is from 1.95 mm to 6.6 mm.9. The spinneret of any preceding or following embodiment / feature / aspect, wherein the OD is from 2 mm to 6 mm.10. The spinneret of any preceding or following embodiment / feature / aspect, wherein the OD is from 3 mm to 5 mm.11. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die has a gap of from 0.1 mm to 0.3 mm.12. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die has a gap / slit width of from 0.7 to 2.13. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die has a slit width / ID of from 0.01 to 1.14. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die has a slit width / OD of from 0.008 to 0.8.15. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die has an OD / slit width of from 5 to 40.16. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arcAttorney Docket No. 3192-114-01PCT shaped die has a [ID / OD]2of from 0.5 to 0.9.17. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die has a thickness of from 1 mm to 10 mm.18. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die has an ID / 2 / slit width of from 6 to 20.19. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die has an ID / 2 / slit width of from 10 to 15.20. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die comprises from 1 arc to 10 arcs.21. The spinneret of any preceding or following embodiment / feature / aspect, wherein the arc shaped die comprises from 1 arc to 4 arcs.22. The spinneret of any preceding or following embodiment / feature / aspect, wherein the spinneret comprises from 1 to 10,000 openings.23. A method of forming a hollow fiber membrane using the spinneret of any preceding or following embodiment / feature / aspect, the method comprising passing at least one thermoplastic polymer through the spinneret to obtain melt-spun fibers, and then stretching the melt-spun fibers.24. The method of any preceding or following embodiment / feature / aspect, wherein the melt spinning of the at least one thermoplastic polymer occurs at a temperature of from 150 °C to 400 °C.25. The method of any preceding or following embodiment / feature / aspect, wherein an extruder pump pumps the at least one thermoplastic polymer to the spinneret, and wherein an extruder pump pressure is from 1400 psi to 3000 psi.26. The method of any preceding or following embodiment / feature / aspect, wherein a line speed is from 5,000 m / min to 10,000 m / min.Attorney Docket No. 3192-114-01PCT27. The method of any preceding or following embodiment / feature / aspect, further comprising crimping the melt-spun fibers.28. The method of any preceding or following embodiment / feature / aspect, further comprising collecting the melt-spun fibers on a wheel.29. The method of any preceding or following embodiment / feature / aspect, further comprising collecting the melt-spun fibers into a bundle.30. The method of any preceding or following embodiment / feature / aspect, further comprising inserting the bundle of melt-spun fibers into a dialyzer module and potting the melt-spun fibers in the dialyzer module.31. A spinneret for making a hollow fiber membrane, the spinneret comprising: a body comprising an inlet surface, an outlet surface, and a bore that runs from the inlet surface to the outlet surface, wherein an inlet to the bore is defined through the inlet surface, and an outlet to the bore is defined through the outlet surface, the outlet comprising an arc shaped die defined by at least one arc shaped slit, wherein the at least one arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD) that satisfies the equation of ID / OD that is up to 0.95, such as an OD of from 1.95 mm to 6.6 mm, a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95.32. The of any preceding or following embodiment / feature / aspect, further comprising an insert disposed within the bore.33. The spinneret of any preceding or following embodiment / feature / aspect, wherein the at least one arc shaped slit is defined between an outer surface of the insert and an inner surface of the bore.34. The spinneret of any preceding or following embodiment / feature / aspect, wherein the insert comprises at least one protrusion radially extending from the outer surface, the at least one protrusion forming a gap of the at least one arc shaped slit.Attorney Docket No. 3192-114-01PCT35. The spinneret of any preceding or following embodiment / feature / aspect, wherein the at least one protrusion comprises a plurality of protrusions such that the at least one arc shaped slit is a plurality of arc shaped slits.36. The spinneret of any preceding or following embodiment / feature / aspect, wherein the insert comprises a plurality of openings in an annular arrangement.37. The spinneret of any preceding or following embodiment / feature / aspect, wherein the insert comprises a plurality of openings in an annular arrangement, the plurality of openings fluidly connecting the inlet with the at least one arc shaped slit.38. The spinneret of any preceding or following embodiment / feature / aspect, wherein the body further comprises a sidewall and at least a portion of the sidewall is threaded.39. The spinneret of any preceding or following embodiment / feature / aspect, wherein the portion of the sidewall that is threaded comprises a smaller diameter than a portion of the sidewall that is unthreaded.40. The spinneret of any preceding or following embodiment / feature / aspect, wherein the at least one arc shaped slit is a plurality of arc shaped slits.41. The spinneret of any preceding or following embodiment / feature / aspect, further comprising a plate disposed at the outlet of the bore, the plate comprising the at least one arc shaped slit.42. The spinneret of any preceding or following embodiment / feature / aspect, wherein the slit width is from 0.1 mm to 0.2 mm.43. The spinneret of any preceding or following embodiment / feature / aspect, wherein the ID / OD is from 0.7 to 0.95.44. The spinneret of any preceding or following embodiment / feature / aspect, wherein the OD is from 1.95 mm to 6.6 mm.

[0134] The present invention can include any combination of these various features or embodiments above and / or below as set forth in sentences and / or paragraphs. Any combinationAttorney Docket No. 3192-114-01PCT of disclosed features herein is considered part of the present invention and no limitation is intended with respect to combinable features.

[0135] Applicants specifically incorporate the entire contents of all cited references in this disclosure. Further, when an amount, concentration, or other value or parameter is given as either a range, a preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

[0136] Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof.

Claims

Attorney Docket No. 3192-114-01PCTWHAT IS CLAIMED IS:

1. A spinneret for making a hollow fiber membrane, the spinneret comprising: an arc shaped die, wherein the arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD) that satisfies an equation of ID / OD that is up to 0.95, a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95.

2. The spinneret of claim 1, wherein the ID is from 1.8 mm to 5 mm.

3. The spinneret of claim 1, wherein the ID is from 2 mm to 4 mm.

4. The spinneret of claim 1, wherein the slit width is from 0.1 mm to 0.2 mm.

5. The spinneret of claim 1, wherein the ID / OD is from 0.7 to 0.95.

6. The spinneret of claim 1, wherein the ID / OD is from 0.8 to 0.95.

7. The spinneret of claim 1, wherein the ID / OD is from 0.9 to 0.95.

8. The spinneret of claim 1, wherein the OD is from 1.95 mm to 6.6 mm.

9. The spinneret of claim 1, wherein the OD is from 2 mm to 6 mm.

10. The spinneret of claim 1, wherein the OD is from 3 mm to 5 mm.

11. The spinneret of claim 1, wherein the arc shaped die has a gap of from 0.1 mm to 0.3 mm.

12. The spinneret of claim 11, wherein the arc shaped die has a gap / slit width of from 0.7 to 2.

13. The spinneret of claim 1, wherein the arc shaped die has a slit width / ID of from 0.01 to 1.Attorney Docket No. 3192-114-01PCT14. The spinneret of claim 1, wherein the arc shaped die has a slit width / OD of from 0.008 to 0.8.

15. The spinneret of claim 1, wherein the arc shaped die has an OD / slit width of from 5 to 40.

16. The spinneret of claim 1, wherein the arc shaped die has a [ID / OD]2of from 0.5 to 0.9.

17. The spinneret of claim 1, wherein the arc shaped die has a thickness of from 1 mm to 10 mm.

18. The spinneret of claim 1, wherein the arc shaped die has an ID / 2 / slit width of from 6 to 20.

19. The spinneret of claim 1, wherein the arc shaped die has an ID / 2 / slit width of from 10 to 15.

20. The spinneret of claim 1, wherein the arc shaped die comprises from 1 arc to 10 arcs.

21. The spinneret of claim 1, wherein the arc shaped die comprises from 1 arc to 4 arcs.

22. The spinneret of claim 1, wherein the spinneret comprises from 1 to 10,000 openings.

23. A method of forming a hollow fiber membrane using the spinneret of claim 1, the method comprising passing at least one thermoplastic polymer through the spinneret to obtain melt- spun fibers, and then stretching the melt-spun fibers.

24. The method of claim 23, wherein the melt spinning of the at least one thermoplastic polymer occurs at a temperature of from 150 °C to 400 °C.

25. The method of claim 23, wherein an extruder pump pumps the at least one thermoplastic polymer to the spinneret, and wherein an extruder pump pressure is from 1400 psi to 3000 psi.Attorney Docket No. 3192-114-01PCT26. The method of claim 23, wherein a line speed is from 5,000 m / min to 10,000 m / min.

27. The method of claim 23, further comprising crimping the melt-spun fibers.

28. The method of claim 23, further comprising collecting the melt-spun fibers on a wheel.

29. The method of claim 23, further comprising collecting the melt-spun fibers into a bundle.

30. The method of claim 29, further comprising inserting the bundle of melt-spun fibers into a dialyzer module and potting the melt-spun fibers in the dialyzer module.

31. A spinneret for making a hollow fiber membrane, the spinneret comprising: a body comprising an inlet surface, an outlet surface, and a bore that runs from the inlet surface to the outlet surface, wherein an inlet to the bore is defined through the inlet surface, and an outlet to the bore is defined through the outlet surface, the outlet comprising an arc shaped die defined by at least one arc shaped slit, wherein the at least one arc shaped die has an inner diameter (ID) of from 1.75 mm to 6 mm, an outer diameter (OD) that satisfies an equation of ID / OD that is up to 0.95, a slit width of from 0.1 mm to 0.3 mm, and an ID / OD of up to 0.95.

32. The spinneret of claim 31, further comprising an insert disposed within the bore.

33. The spinneret of claim 32, wherein the at least one arc shaped slit is defined between an outer surface of the insert and an inner surface of the bore.

34. The spinneret of claim 33, wherein the insert comprises at least one protrusion radially extending from the outer surface, the at least one protrusion forming a gap of the at least one arc shaped slit.Attorney Docket No. 3192-114-01PCT35. The spinneret of claim 34, wherein the at least one protrusion comprises a plurality of protrusions such that the at least one arc shaped slit is a plurality of arc shaped slits.

36. The spinneret of claim 32, wherein the insert comprises a plurality of openings in an annular arrangement.

37. The spinneret of claim 32, wherein the insert comprises a plurality of openings in an annular arrangement, the plurality of openings fluidly connecting the inlet with the at least one arc shaped slit.

38. The spinneret of claim 31, wherein the body further comprises a sidewall and at least a portion of the sidewall is threaded.

39. The spinneret of claim 38, wherein the portion of the sidewall that is threaded comprises a smaller diameter than a portion of the sidewall that is unthreaded.

40. The spinneret of claim 31, wherein the at least one arc shaped slit is a plurality of arc shaped slits.

41. The spinneret of claim 31, further comprising a plate disposed at the outlet of the bore, the plate comprising the at least one arc shaped slit.

42. The spinneret of claim 31, wherein the slit width is from 0.1 mm to 0.2 mm.

43. The spinneret of claim 31, wherein the ID / OD is from 0.7 to 0.95.

44. The spinneret of claim 31, wherein the OD is from 1.95 mm to 6.6 mm.

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