A spinneret, a breaker plate, and a die body having contoured surfaces with no flat areas between adjacent holes

Abstract

A spinneret for extruding fibers includes a plate having a proximal surface and a distal surface. The spinneret includes a plurality of holes formed in the plate extending between the proximal and distal surfaces of the plate. The holes are spaced apart from one another, and each hole has a distal end extending along a central axis. The spinneret has a plurality of contoured entrance zones formed in the proximal surface of the plate, whereby each contoured entrance zone is associated with one of the holes. Each contoured entrance zone extends distally from the proximal surface of the plate to the proximal end of its associated hole. Each contoured entrance zone does not substantially have a planar or flat surface perpendicular to the direction of the central axis of the distal end of its associated hole.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This patent application claims the benefit of U.S. Provisional Application No. 63 / 016,045, filed April 27, 2020, the disclosure of which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION This patent application relates generally to systems, devices, and methods used to make sutures, and more specifically to spinnerets, breaker plates, and die bodies used to extrude suture fibers. [Background technology]

[0003] 1 and 2 show a prior art spinneret 50 having a flat top surface 52, a flat bottom surface 54, and a plurality of holes 56 extending from the flat top surface 52 to the flat bottom surface 54. A polymer melt or solution is forced through the holes 56 to form fibers used to make sutures. The spinneret 50 has flat, planar surfaces 58 (shaded blue in FIG. 1) located between the holes 56. As the polymer melt or solution is extruded through the spinneret 50, the flow rate of the polymer melt slows and / or stagnates on the polymer wetting surfaces 58 (i.e., the planar surfaces perpendicular to the direction of the central axes of the distal ends of each hole 56).

[0004] FIG. 2 illustrates the flow velocity (mm / sec) profile of the polymer melt as it flows through the holes 56 and across the flat polymer-wetted surface 58 of the spinneret 50. The polymer melt flows through the holes 56 at a flow velocity close to the desired maximum flow velocity. The polymer melt flow velocity on the flat polymer-wetted surface 58 of the spinneret 50 includes a "dead area" where the flow velocity is slower, typically less than 5% of the maximum flow velocity. In some cases, the "dead area" on the spinneret is estimated to be as much as 91% of the total color-shaded area (including the hole entrance zone) in FIG. 2 (i.e., the purple-shaded area on the flat top surface 52 of the spinneret). The space above the shaded area (i.e., the polymer-wetted surface) can be filled by the polymer melt under extrusion pressure. This situation is problematic because the polymer melt tends to stagnate in the "dead area" of the polymer-wetted surface 58, resulting in significant polymer degradation at high extrusion temperatures.

[0005] 3 and 4 show a second prior art spinneret 50' having a flat top surface 52', a flat bottom surface 54', and a plurality of holes 56' extending from the flat top surface 52' to the flat bottom surface 54'. The holes 56' are arranged in a circular pattern extending around the base of a cone 60' that protrudes above the flat top surface 52' of the spinneret 50'. FIG. 4 shows "dead areas" 58' in the flat top surface 52' where the polymer melt flow rate is less than 5% of the desired maximum flow rate. The "dead areas" are located between adjacent holes 56'. Although the "dead area" 58' shown in Figures 3 and 4 comprises a lower percentage of the "dead area" found in the first prior art spinneret 50 shown in Figures 1 and 2, the "dead area" 58' is still approximately 43% of the total color-shaded area in Figure 4 (including holes 56'') of the flat top surface of the spinneret 50'. Thus, if the polymer melt extruding through the holes 56' of the spinneret 50' slows down and stagnates in the "dead area" 58', significant degradation of the polymer melt occurs at high extrusion temperatures.

[0006] Some efforts have been made to design spinnerets to improve the flow rate of the polymer solution through the holes in the spinneret. For example, Chinese Patent Publication No. 202925165 modifies the shape of the trenches formed on the proximal surface of the spinneret to improve the spinning potential energy and fluidity of the spinning solution to prevent the spinning solution from being decomposed and carbonized.

[0007] FIG. 5 is a cross-sectional view of a spinneret 50″ disclosed in CN202925165. The spinneret 50″ has a top surface 52″, a bottom surface 54″, and a plurality of holes 56″ extending from the top surface 52″ to the bottom surface 54″. The spinneret 50″ includes inner grooves 60″ and outer grooves 62″ formed in the top surface 52″ of the spinneret. A set of inner holes 56A″ is located within the inner grooves 60″, and a set of outer holes 56B″ is located within the outer grooves 62″. Within each groove, the respective holes 56A″ and 56B″ are spaced apart from one another such that a flat surface or dead zone 58″ is located between adjacent holes 56A″, 56B″. As the polymer solution flows through the spinneret 50'', the velocity of the polymer material within the dead zone 58'' is significantly lower than the preferred maximum velocity of the polymer solution, resulting in the polymer solution stagnating within the dead zone 58'', resulting in significant degradation of the polymer material at high extrusion temperatures.

[0008] Despite the above advances, existing spinnerets remain inadequate because they have flat spots or dead areas between adjacent holes that cause polymer degradation and non-uniform fiber structure formation, which contributes to significant variations in fiber strength and / or fiber toughness. Summary of the Invention [Problem to be solved by the invention]

[0009] Thus, there remains a need for an improved spinneret that minimizes or eliminates flat spots or dead areas between adjacent holes, maximizes the flow rate of the polymer melt as it flows through the spinneret, minimizes polymer degradation and / or variations in fiber toughness within and / or between fiber spools, and significantly increases the average toughness and / or strength of the extruded fibers. [Means for solving the problem]

[0010] In one embodiment, a spinneret used to form multifilaments from a polymer preferably includes a plate having a top or proximal surface, a bottom or distal surface, and adjacent holes extending from the proximal surface toward the distal surface of the plate.

[0011] In one embodiment, the spinneret plates preferably have an outer diameter of about 30 to 110 mm.

[0012] In one embodiment, each hole formed in the plate desirably has a proximal end and a distal end.

[0013] In one embodiment, the number of holes formed in the plate may be 4 to 80.

[0014] In one embodiment, 4 to 80 holes may be positioned in 1 to 3 concentric rings having an outer diameter in the range of 10 to 90 mm.

[0015] In one embodiment, the distance between any two adjacent holes may range from about 3 to 20 mm.

[0016] In one embodiment, the holes are spaced apart from one another without flat surfaces between adjacent holes.

[0017] In one embodiment, the contoured inlet zone preferably surrounds the proximal end of each hole formed in the plate, hi one embodiment, the contoured inlet zone preferably comprises a contoured surface extending from the proximal surface of the plate (e.g., the polymer-wetted surface of the plate) to the proximal end of each hole.

[0018] In one embodiment, the contoured inlet zone surrounding the proximal end of each hole is immediately adjacent to the contoured inlet zone surrounding each adjacent hole such that substantially no flat or planar surface perpendicular to the direction of the central axis of the distal end of the hole (e.g., a central axis extending along the length of the capillary hole) remains between adjacent holes on the proximal surface (e.g., polymer-wetted surface) of the plate. The contoured surface of the contoured inlet zone surrounding the proximal end of the hole can include angled surfaces and curved surfaces, including concave and convex curved surfaces.

[0019] In one embodiment, the plate may include a centrally located conical projection extending above the flat proximal surface of the plate and an adjacent hole located at the base of the conical projection. In one embodiment, the holes may be arranged in an annular or ring-shaped configuration around the base of the cone. In one embodiment, a ring (e.g., a slot) having an annular shape may be formed in the proximal surface of the plate, and the hole may be located within the ring.

[0020] In one embodiment, the spinneret plate can have an inner ring including a first set of inner holes and an outer ring including a second set of outer holes. In one embodiment, the outer ring can surround the inner ring. In one embodiment, the inner and outer rings can be concentric and can surround the base of a conical projection that projects above the proximal surface of the spinneret.

[0021] In one embodiment, the spinneret can have a plate with two or more rings (e.g., three rings) formed on the top or proximal surface of the plate. In one embodiment, holes are formed in each of the two or more rings. In one embodiment, a contoured entrance zone is formed in the ring at the proximal end of each hole such that there are substantially no flat or planar surfaces within the polymer wetted region of the spinneret and between adjacent holes that are perpendicular to the direction of the central axis of the distal end of each hole (e.g., the central axis of the capillary hole). In one embodiment, the central axis at the distal end of each hole is preferably a longitudinal axis extending through the capillary that extends to the bottom or distal surface of the spinneret plate.

[0022] In one embodiment, the contoured inlet zone is proximal to the proximal end of each hole such that there is substantially no flat or planar surface perpendicular to the direction of the central axis of the distal end of each hole (e.g., the central axis of the capillary hole).

[0023] In one embodiment, the base of the conical projection preferably has an outer diameter of at least 20 mm and a height of about 20-40 mm.

[0024] In one embodiment, the spinneret preferably includes a plate having 4 to 80 holes, with a central cone protruding above the proximal surface of the plate. In one embodiment, the spinneret preferably includes contoured entrance zones formed in the proximal surface (e.g., polymer-wetted surface) of the plate, whereby each contoured entrance zone is associated with the proximal end of one of the holes formed in the plate. In one embodiment, the contoured entrance zones are located within the wetting region of the spinneret plate such that there is no flat surface between adjacent holes that is perpendicular to the direction of the central axes of the distal ends of the holes.

[0025] In one embodiment, a polymer extrusion die assembly is configured for the extrusion of multifilament and / or suture fibers. In one embodiment, the polymer extrusion die assembly preferably includes a die body having a conical hollow center and a spinneret as disclosed herein having 4 to 80 holes with a proximal polymer wetting surface that does not have a flat surface perpendicular to the central axis of the distal end of the holes. In one embodiment, when the spinneret is assembled with the die body, the conical projections of the spinneret are positioned within the conical hollow center of the die body.

[0026] In one embodiment, a breaker plate used to extrude multifilaments from a polymer preferably includes a cylindrical hollow space for holding filtering elements (e.g., filtering screens) and / or mixing elements (e.g., stainless steel balls), and a perforated plate with contoured inlet and outlet zones for the flow holes on both the proximal and distal surfaces of the plate, with substantially no flat surfaces perpendicular to the central axes of the respective flow holes. In one embodiment, the breaker plate preferably includes ridges extending between the contoured inlet zones that are in the same plane as the proximal surface of the plate to contact and support the filtering elements and minimize the risk of deforming, collapsing, and / or damaging the filtering elements under high pressure during the extrusion process. Incorporating the breaker plate disclosed herein into a polymer melt extrusion die preferably minimizes polymer degradation, improves fiber uniformity, and significantly increases the fiber strength of the extruded polymer filaments.

[0027] In one embodiment, a breaker plate for extruding fibers preferably includes a plate having a proximal surface and a distal surface, and a plurality of holes formed in the plate extending between the proximal and distal surfaces of the plate, whereby the holes are spaced apart from one another and each hole extends along a central axis.

[0028] In one embodiment, the breaker plate includes a plurality of contoured entry zones formed in the proximal surface of the plate, whereby each contoured entry zone is associated with one of the holes. In one embodiment, each contoured entry zone preferably extends distally from the proximal surface of the plate to the proximal end of its associated hole. In one embodiment, each contoured entry zone desirably has substantially no planar or flat surface perpendicular to the central axis of its associated hole.

[0029] In one embodiment, the breaker plate may include a plurality of contoured exit zones formed in the distal surface of the plate, whereby each contoured exit zone is associated with one of the holes. In one embodiment, each contoured exit zone desirably extends distally from the distal end of its associated hole to the distal surface of the plate, whereby the contoured exit zone does not have substantially a planar or flat surface perpendicular to the central axis of its associated hole.

[0030] In one embodiment, each hole formed in the plate has a proximal end closer to the proximal surface of the plate and a distal end closer to the distal surface of the plate.

[0031] In one embodiment, each contoured entrance zone preferably surrounds the proximal end of its associated hole, and the contoured entrance zone desirably includes a contoured surface extending from the proximal surface of the plate to the proximal end of the hole.

[0032] In one embodiment, the contoured inlet zone surrounding each hole defines a wetting region on the proximal surface of the plate immediately adjacent to the contoured inlet zone surrounding each adjacent hole, and the wetting region does not have a planar or flat surface perpendicular to the central axis of the respective hole.

[0033] In one embodiment, the contoured entrance zone may include a contoured surface selected from the group consisting of an angled surface, a curved surface, a concave curved surface, and a convex curved surface.

[0034] In one embodiment, each contoured exit zone preferably surrounds the distal end of its associated hole, and the contoured exit zone desirably includes a contoured surface extending from the distal surface of the plate to the distal end of the hole.

[0035] In one embodiment, the contoured exit zone surrounding each hole defines a wetting region on the distal surface of the plate immediately adjacent to the contoured exit zone surrounding each adjacent hole, and the wetting region does not have a planar or flat surface perpendicular to the central axis of the respective hole.

[0036] In one embodiment, the contoured exit zone preferably comprises a contoured surface selected from the group consisting of an angled surface, a curved surface, a concave curved surface, and a convex curved surface.

[0037] In one embodiment, there are approximately 3 to 60 holes formed in the breaker plate.

[0038] In one embodiment, the breaker plate may include a tubular wall directly connected to the proximal surface of the plate, hi one embodiment, the tubular wall preferably defines a cylindrical hollow space adapted to receive polymer mixing and / or filtering elements, such as sand, stainless steel balls, sintered mesh screens, etc., to homogenize the polymer melt and / or filter impurities from the polymer melt.

[0039] In one embodiment, the breaker plate may be located anywhere in the melt flow path from the polymer source, such as the extruder or metering pump block outlet, to the inlet of the fiber extrusion die body or die assembly.

[0040] In one embodiment, a die body used for extruding multifilaments from a polymer has a plurality of flow distribution channels in the upper part of the die body and a hollow cone in the lower part of the die body that forms a thin layer of flow channels when assembled with a matching spinneret / conical die for extrusion.

[0041] In one embodiment, the die body has less free volume (hence less residence time) and faster heat transfer than is achieved when using a conventional die body having an inverted conical hollow space for the polymer inlet stream. In one embodiment, the inlet zone of the flow channel is contoured so that there are substantially no flat surfaces perpendicular to the polymer flow on either the inlet or outlet side of the flow channel.

[0042] In one embodiment, the contoured inlet zone ridges are preferably all in the same plane, so that the ridges can directly contact and support a filtering element (e.g., a mesh filtering screen) for filtration without the use of a separate breaker plate. In one embodiment, the adapter tube can be attached or fabricated as a single unit to the proximal end of the die body to form a tubular hollow space adapted to hold one or more filtering and / or mixing elements.

[0043] In one embodiment, a die body for extruding fibers preferably includes an inlet opening having a plurality of contoured inlet zones having substantially no flat surfaces perpendicular to the central axis of the die body, a conical hollow space distal to the die body, and a plurality of flow channels for polymer flow through the contoured inlet zones to an outlet region at the top of the die body or near the tip region of the conical hollow space.

[0044] In one embodiment, the die body may have between about 3 and 60 flow channels.

[0045] In one embodiment, the flow channels may extend along respective axes that are parallel to the central axis of the die body.

[0046] In one embodiment, the flow channels are preferably inclined at an angle of about 15 to 50 degrees relative to the central axis of the die body so that all of the outlets of the flow channels are above or near the apex region of the conical hollow space of the die body.

[0047] In one embodiment, the contoured entrance zone desirably comprises a contoured surface selected from the group consisting of an angled surface, a curved surface, a concave curved surface, and a convex curved surface.

[0048] In one embodiment, a polymer extrusion die assembly for extruding suture fibers may include a conical die having a conical-shaped center and a die body having an upper portion including a plurality of flow distribution channels, a lower portion including a conical hollow center, and a contoured inlet zone in communication with the proximal ends of the flow distribution channels. In one embodiment, the contoured inlet zone is substantially free of flat surfaces that are perpendicular to the central axis of the die body. In one embodiment, a tubular adapter may be attached to the inlet opening of the die body.

[0049] In one embodiment, the tubular adapter is attachable to the proximal end of the die body.

[0050] In one embodiment, the tubular adapter may be integrally formed with the die body.

[0051] In one embodiment, the tubular adapter can include a filter holder breaker plate that is attachable to the proximal end of the die body.

[0052] These and other preferred embodiments of the present invention are described in more detail below. [Brief explanation of the drawings]

[0053] [Figure 1] FIG. 1 is a perspective view of a prior art spinneret having holes for extruding a flowable polymer. [Figure 2] 2 illustrates the flow velocity profile of a polymer melt as it flows through the holes and across the polymer wetted surface of the prior art spinneret shown in FIG. 1. [Figure 3] FIG. 1 is a perspective view of a second prior art spinneret having holes for extruding a flowable polymer and a cone protruding from the top surface of the plate. [Figure 4] 4 shows the flow velocity profile of the polymer melt as it flows through the holes and across the polymer wetted surface of the second prior art spinneret shown in FIG. 3. [Figure 5] FIG. 1 is a perspective cross-sectional view of a third prior art spinneret used to extrude flowable polymers. [Figure 6A] FIG. 1 is a perspective view of the proximal end of a polymer extrusion die assembly including a die body, a die retainer ring, and a spinneret according to one embodiment of the present patent application. [Figure 6B] 6B is a perspective view of the distal end of the polymer extrusion die assembly shown in FIG. 6A, including the die body, die retainer ring, and spinneret. [Figure 7A] FIG. 6C is an exploded view of the polymer extrusion die assembly shown in FIGS. 6A and 6B, including the die body, die retainer ring, and spinneret. [Figure 7B] FIG. 7B is another exploded view of the polymer extrusion die assembly shown in FIGS. 6A-6B and 7A. [Figure 8A] FIG. 7C is a perspective view of the proximal end of the die body shown in FIGS. 7A and 7B. [Figure 8B] FIG. 8B is a proximal end view of the die body shown in FIG. 8A. [Figure 8C] FIG. 8C is a perspective view of the distal end of the die body shown in FIGS. 8A and 8B. [Figure 8D] FIG. 8D is a distal end view of the die body shown in FIGS. 8A-8C. [Figure 9A] FIG. 8E is a cross-sectional view of the die body shown in FIGS. 8A to 8D. [Figure 9B] FIG. 8E is another cross-sectional view of the die body shown in FIGS. 8A-8D. [Figure 10A] FIG. 7C is a perspective view of the proximal end of the die retainer ring shown in FIGS. 7A and 7B. [Figure 10B] FIG. 10B is a proximal end view of the die retainer ring shown in FIG. 10A. [Figure 10C] FIG. 10C is a perspective view of the distal end of the die retainer ring shown in FIGS. 10A and 10B. [Figure 10D] FIG. 10B is a distal end view of the die retainer ring shown in FIGS. 10A-10C. [Figure 11A] FIG. 16 is a cross-sectional view of the die retainer ring shown in FIGS. 10A to 10D. [Figure 11B] FIG. 16 is another cross-sectional view of the die retainer ring shown in FIGS. 10A to 10D. [Figure 12A] FIG. 7C is a proximal view of the spinneret shown in FIGS. 7A and 7B. [Figure 12B] FIG. 12B is a top or proximal side view of the spinneret shown in FIG. 12A. [Figure 12C] FIG. 12C is a perspective view of the distal side of the spinneret shown in FIGS. 12A and 12B. [Figure 12D] FIG. 12C is a bottom or distal side view of the spinneret shown in FIGS. 12A-12C. [Figure 13A] FIG. 12B is a side elevation view of the spinneret shown in FIGS. 12A-12D. [Figure 13B] FIG. 13B is a cross-sectional view of the spinneret shown in FIGS. 12A to 12D and 13A. [Figure 14A] FIG. 12C is a perspective view of a section of the proximal side of the spinneret shown in FIGS. 12A and 12B with holes passing through the plate of the spinneret, according to one embodiment of the present patent application. [Figure 14B] FIG. 14B is a cross-sectional view of a section of the spinneret shown in FIG. 14A. [Figure 14C] FIG. 14C is a side view of a cross-sectional view of a section of the spinneret shown in FIG. 14B. [Figure 15] 14A-14C illustrate a method of making the spinneret shown in FIGS. 14A-14C according to one embodiment of the present patent application. [Figure 16A] 1 illustrates a first step in a method of making a spinneret according to one embodiment of the present patent application. [Figure 16B] 1 illustrates a second stage of a method for making a spinneret according to an embodiment of the present patent application. [Figure 16C]1 illustrates a third stage of a method for making a spinneret according to an embodiment of the present patent application. [Figure 16D] FIG. 16D is an enlarged view of a section of the spinneret shown in FIG. 16C. [Figure 17A] 6A and 6B, including the die body of FIGS. 8A-8D and 9A-9B, the die retainer ring of FIGS. 10A-10D and 11A-11B, and the spinneret of FIGS. 12A-12D, 13A-13B, 14A-14C, 15A-15C, and 16, according to one embodiment of the present patent application. [Figure 17B] 17B is another cross-sectional view of the polymer extrusion die assembly of FIG. 17A, including the die body, die retainer ring, and spinneret. [Figure 18A] FIG. 10 is a perspective view of the proximal side of a spinneret according to another embodiment of the present patent application. [Figure 18B] FIG. 18B is a top or proximal side view of the spinneret shown in FIG. 18A. [Figure 18C] FIG. 18C is a perspective view of the distal side of the spinneret shown in FIGS. 18A and 18B. [Figure 18D] FIG. 18B is a bottom distal side view of the spinneret shown in FIGS. 18A-18C. [Figure 19A] FIG. 18B is a side elevation view of the spinneret shown in FIGS. 18A-18D. [Figure 19B] FIG. 19B is a cross-sectional view of the spinneret shown in FIGS. 18A to 18D and 19A. [Figure 19C] FIG. 19C is a cross-sectional view of a section of the spinneret shown in FIG. 19B. [Figure 19D] FIG. 19D is an enlarged view of a section of the spinneret shown in FIG. 19C. [Figure 20A] FIG. 10 is a perspective view of the proximal side of a spinneret according to another preferred embodiment of the present patent application. [Figure 20B] FIG. 20B is a top or perspective side view of the spinneret shown in FIG. 20A. [Figure 20C] FIG. 26 is a perspective view of the distal side of the spinneret shown in FIGS. 20A-20B. [Figure 20D]FIG. 20B is a bottom or distal side view of the spinneret shown in FIGS. 20A-20C. [Figure 21A] FIG. 20B is a side elevation view of the spinneret shown in FIGS. 20A-20D. [Figure 21B] FIG. 21B is a cross-sectional view of the spinneret shown in FIGS. 20A to 20D and 21A. [Figure 21C] FIG. 21C is a cross-sectional view of a section of the spinneret shown in FIG. 21B. [Figure 21D] FIG. 21D is an enlarged view of a section of the spinneret shown in FIG. 21C. [Figure 22] 18A-18D illustrate the flow velocity profile of a polymer melt as it flows through the holes and across the polymer wetted surface of the spinneret shown in FIGS. 18A-18D. [Figure 23A] FIG. 1 is a perspective view of a prior art breaker plate for use with a polymer extrusion die assembly. [Figure 23B] FIG. 23B is a cross-sectional view of the breaker plate shown in FIG. 23A. [Figure 24] FIG. 1 is a perspective view of a prior art breaker plate and a filtering screen disposed within the cylindrical hollow space of the breaker plate. [Figure 25A] FIG. 1 is a perspective view of the proximal end of a prior art die body. [Figure 25B] 25B shows the breaker plate of FIG. 24 assembled with the proximal end of the die body of FIG. 25A. [Figure 26A] FIG. 1 is an exploded view of a polymer extrusion die assembly including a breaker plate, a die body, a spinneret, and a die retainer ring according to an embodiment of the present patent application. [Figure 26B] FIG. 26B is another exploded view of the polymer extrusion die assembly shown in FIG. 26A. [Figure 27A] FIG. 26C is a perspective view of the proximal end of the breaker plate shown in FIGS. 26A and 26B. [Figure 27B] FIG. 27B is a proximal end view of the breaker plate shown in FIG. 27A. [Figure 27C] FIG. 27C is a distal end view of the breaker plate shown in FIGS. 27A and 27B. [Figure 27D]FIG. 27D is a cross-sectional view of the breaker plate shown in FIGS. 27A to 27C. [Figure 27E] FIG. 27B is another cross-sectional view of the breaker plate shown in FIGS. 27A to 27D. [Figure 28] FIG. 27B is a perspective view of a section of the proximal surface of the breaker plate shown in FIGS. 27A-27E, including a contoured entry zone and holes passing through the breaker plate, according to an embodiment of the present patent application. [Figure 29A] FIG. 10 is a proximal end view of a die body and a breaker plate adapted to be assembled with the die body, according to one embodiment of the present patent application. [Figure 29B] 29B shows the breaker plate of FIG. 29A assembled with the proximal end of the die body shown in FIG. 29A. [Figure 29C] FIG. 29C is a cross-sectional view of the breaker plate and die body of FIG. 29B. [Figure 30A] 1 illustrates a first step in a method for inserting a filtering screen into a cylindrical hollow space of a breaker plate according to one embodiment of the present patent application. [Figure 30B] 10 illustrates a second step in a method for inserting a filtering screen into a cylindrical hollow space of a breaker plate according to an embodiment of the present patent application. [Figure 30C] FIG. 30C is a cross-sectional view of a polymer extrusion die assembly including the breaker plate and die body of FIG. 30B assembled with a spinneret and die retainer ring according to an embodiment of the present patent application. [Figure 31] FIG. 1 is a cross-sectional view of a prior art die body. [Figure 32] FIG. 2 is a cross-sectional view of another prior art die body. [Figure 33A] FIG. 1 is an exploded view of a polymer extrusion die assembly including a tubular adapter, a filtering screen, a die body, and a spinneret according to one embodiment of the present patent application. [Figure 33B] FIG. 33B is another exploded view of the polymer extrusion die assembly shown in FIG. 33A. [Figure 34A] FIG. 33C is a perspective view of the proximal end of the die body shown in FIGS. 33A and 33B. [Figure 34B] FIG. 34B is a proximal end view of the die body shown in FIG. 34A. [Figure 34C] FIG. 34C is a perspective view of the distal end of the die body shown in FIGS. 34A and 34B. [Figure 34D] FIG. 34D is a distal end view of the die body shown in FIGS. 34A-34C. [Figure 34E] FIG. 34B is a cross-sectional view of the die body shown in FIGS. 34A to 34D. [Figure 34F] FIG. 34B is another cross-sectional view of the die body shown in FIGS. 34A to 34E. [Figure 35] FIG. 34A is a perspective view of a section of the proximal side of the die body shown in FIGS. 34A-34F with a contoured inlet zone surrounding the polymer melt flow holes, according to an embodiment of the present patent application. [Figure 36A] FIG. 33B is a perspective view of the tubular adapter shown in FIG. 33A. [Figure 36B] FIG. 36B is a proximal end view of the tubular adapter shown in FIG. 36A. [Figure 36C] FIG. 36C is a cross-sectional view of the tubular adapter shown in FIGS. 36A and 36B. [Figure 37A] FIG. 1 is a cross-sectional view of a polymer extrusion die assembly including a tubular adapter, a die body, a spinneret, and a filtering screen adapted to be inserted into the cylindrical hollow space of the tubular adapter to cover the polymer melt flow holes at the proximal end of the die body, according to one embodiment of the present patent application. [Figure 37B] 37B is a cross-sectional view of the polymer extrusion die assembly of FIG. 37A with a filtering screen inserted into the cylindrical hollow space of the tubular adapter to cover the polymer melt flow holes at the proximal end of the die body. [Figure 38] FIG. 1 is a cross-sectional view of a polymer extrusion die assembly including a die body and a spinneret according to one embodiment of the present patent application. [Figure 39A] FIG. 1 is a cross-sectional view of a spinneret blank being machined to create a spinneret according to one embodiment of the present patent application. [Figure 39B]39B illustrates a method for machining the spinneret blank of FIG. 39A to make a spinneret, according to one embodiment of the present patent application. [Figure 39C] FIG. 1 is a perspective view of a machined spinneret according to one embodiment of the present patent application. DETAILED DESCRIPTION OF THE INVENTION

[0054] 6A-6B and 7A-7B, in one embodiment, a polymer extrusion die assembly 100 preferably includes a die body 102 (which may also be referred to as a "die block"), a die retainer ring 104, and a spinneret 106 disposed between the die body 102 and the die retainer ring 104. The polymer extrusion die assembly 100 preferably has a proximal opening 108 adapted to receive a material such as a polymer melt and a distal opening 110 configured to dispense filaments or fibers from a lower end of the polymer extrusion die assembly. The extruded fibers may be used to make sutures.

[0055] 8A-8D, in one embodiment, the die body 102 preferably has a leading or proximal end 112 with a flat top surface 114 and a trailing or distal end 116 with a flat bottom surface 118. The proximal end 112 of the die body 102 desirably includes a proximal opening 108 for directing the polymer melt into the proximal end of the polymer extrusion die assembly 100 (FIG. 6A).

[0056] 8A and 8B, in one embodiment, the die body 102 of the polymer extrusion die assembly 100 (FIGS. 6A-6B) preferably includes an upper groove 120 having an annular shape formed in the upper surface 114 of the die body and surrounding the proximal opening 108 of the polymer extrusion die assembly. In one embodiment, the die body 102 desirably includes spaced apart alignment openings 122A-122D formed in the upper surface 114 of the die body 102 for aligning the die body 102 with opposing tooling of the die assembly.

[0057] 8C and 8D, in one embodiment, the lower, rear, and / or distal end 116 of the die body 102 desirably includes a flat bottom surface 118 and a bottom groove 124 having an annular shape formed in the flat bottom surface 118 and surrounding a polymer melt exit opening 126. As described in more detail herein, the annular bottom groove 124 is sized and configured to seat a plate of the spinneret 106 (FIGS. 7A and 7B).

[0058] In one embodiment, the die body 102 is adapted to receive alignment bolts for aligning the die body 102 with the die retainer ring 104 (FIG. 6A), and preferably includes bolt holes 128A-128D formed in the flat bottom surface 118 of the die body 102.

[0059] 8D, in one embodiment, the annular bottom groove 124 of the die body 102 defines an outer diameter OD1 that substantially matches the outer diameter of the plates of the spinneret 106 (FIG. 7A) that is assembled with the die body 102, as described in more detail herein. In one embodiment, the outer diameter OD1 of the annular bottom groove 124 is preferably about 45-65 millimeters, more preferably about 50-60 millimeters, and even more preferably about 55-60 millimeters.

[0060] 9A and 9B, in one embodiment, the die body 102 preferably includes a proximal end 112 having an upper flat surface 114 and a distal end 116 having a flat bottom surface 118. The die body 102 includes an annular upper groove 120 formed in the flat upper surface 114 and surrounding a proximal opening 108 (FIG. 6A) located at the upper end of the polymer extrusion die assembly 100.

[0061] In one embodiment, the die body 102 desirably includes an annular bottom groove 124 formed in the flat bottom surface 118 of the die body 102 and surrounding a polymer melt exit opening 126 located at the distal end 116 of the die body 102. In one embodiment, the proximal opening 108 located at the upper end 112 of the die body 102 includes sloped sidewalls 130 that converge toward each other to define an inverted cone that directs the polymer melt into a restricted flow region 132 of the polymer melt flow path. In one embodiment, the sidewalls 130 of the proximal opening 108 converge toward each other until reaching the restricted flow region 132 of the polymer melt flow path. In one embodiment, the polymer melt exit opening 126 at the distal or lower end 116 of the die body 102 preferably includes sloped sidewalls 134 that slope outwardly away from each other between the restricted flow region 132 and the annular bottom groove 124 of the die body. The sloped sidewall 134 of the polymer melt exit opening 126 preferably defines an upright conical shape that substantially matches the shape of a cone that protrudes above the proximal surface of the plate of a spinneret that is inserted into the polymer melt exit opening 126, as described in more detail herein. In one embodiment, the polymer melt exit opening 126 has the shape of a hollow cone that is adapted to receive the conical protrusion of the spinneret 106 (FIG. 7B).

[0062] In one embodiment, the die body 102 includes bottom bolt holes 128 formed in the flat bottom surface 118 of the die body 102 for receiving alignment bolts to align the die body 102 with the die retainer ring 104 (FIG. 6A), as described in more detail herein.

[0063] 10A-10D, in one embodiment, the die retainer ring 104 of the polymer extrusion die assembly 100 (FIGS. 6A and 6B) preferably includes a top, leading, and / or proximal end 136 having a flat top surface 138, and a bottom, trailing, and / or distal end 140 having a flat bottom surface 142. In one embodiment, the die retainer ring 104 preferably includes an annular top groove 144 formed in the flat top surface 138 of the die retainer ring 104. The annular top groove 144 is sized and shaped to seat an alignment protrusion extending from the underside of a plate of the spinneret 106 (FIG. 7A), as described in more detail herein.

[0064] In one embodiment, the die retainer ring 104 preferably includes a central opening 146 that extends from the flat top surface 138 to the flat bottom surface 142 of the die retainer ring. In one embodiment, an annular upper groove 144 of the die retainer ring 104 surrounds the central opening 146. In one embodiment, the outer periphery of the annular upper groove 144 preferably defines a second outer diameter OD2 that is less than the first outer diameter OD1 ( FIG. 8D ) of the annular bottom groove 124 at the lower end of the die body 102. In one embodiment, the second outer diameter OD2 of the annular upper groove 144 of the die retainer ring 104 is sized to accommodate alignment protrusions extending from the underside of a spinneret plate for aligning the spinneret with the die retainer ring 104, as described in more detail herein. In one embodiment, when the spinneret plate is seated in the annular upper groove 144 of the die retainer ring 104, the distal ends of the capillary openings on the underside of the spinneret plate are preferably surrounded by the annular upper groove 144 of the die retainer ring 104, so that polymer fibers extruded from the capillary openings in the spinneret plate pass through the central opening 146 of the die retainer ring 104.

[0065] In one embodiment, die retainer ring 104 preferably includes spaced bolt holes 148A-148D adapted to receive alignment bolts for aligning die retainer ring 104 with die body 102 (FIG. 7A). In one embodiment, an alignment bolt may be inserted through each of spaced bolt holes 148A-148D.

[0066] 11A and 11B, in one embodiment, the die retainer ring 104 preferably includes a proximal end 136 having a flat top surface 138 and a distal end 140 having a flat bottom surface 142. An annular upper groove 144 is formed in the flat top surface 138 of the die retainer ring 104. A central opening 146 preferably extends through the center of the die retainer ring 104 from the flat top surface 138 at the proximal end 136 of the die retainer ring 104 to the flat bottom surface 142 at the distal end 140 of the die retainer ring 104.

[0067] 11B, in one embodiment, an annular upper groove 144 formed in the flat upper surface 138 of the die retainer ring 104 defines a second outer diameter OD2 that preferably matches the outer diameter of an alignment protrusion extending from the underside of the plate of the spinneret 106 (FIG. 7A) for aligning the spinneret with the central opening 146 of the die retainer ring 104. The annular upper groove 144 serves as a seating surface for the underside or distal side of the spinneret plate to prevent the spinneret plate from shifting and / or moving relative to the die retainer ring 104.

[0068] 12A-12D, in one embodiment, spinneret 106 (FIG. 7A), also commonly referred to as a die, preferably includes a plate 150 having a top or proximal surface 152 and a bottom or distal surface 154. In one embodiment, plate 150 preferably has a periphery 156 defining an outer diameter OD3 that substantially corresponds to the outer diameter OD1 (FIG. 8D) of annular bottom groove 124 in die body 102 for assembling the spinneret with the lower or distal end of the die body. Plate 150 may have an annular or circular shape, although in other embodiments, the plate may have a square or rectangular shape or may have one or more flat sides.

[0069] 12A and 12B, in one embodiment, the spinneret 106 preferably includes a cone 158 that protrudes above the proximal surface 152 of the plate 150. The cone 158 desirably includes a top portion 160 that is adapted to be inserted into the polymer melt exit opening 126 (FIG. 9B) located at the distal end of the die body 102. The cone 158 preferably includes a base portion 162 at its lower end that is substantially aligned with the plane defined by the proximal surface 152 of the plate 150.

[0070] In one embodiment, the proximal surface 152 of the spinneret plate 150 preferably includes a wetting region 153 and a sealed region 155 surrounding the wetting region 153. In one embodiment, the wetting region 153 of the proximal surface 152 of the plate 150 is the region of the plate 150 that contacts the polymer melt as it is extruded through the spinneret 106. The sealed region 155 of the proximal surface 152 is preferably assembled between components of a polymer extrusion die assembly and is the region of the plate that does not contact the polymer melt as it flows through the polymer extrusion die assembly. In one embodiment, the wetting region 153 of the proximal surface 152 of the plate 150 preferably surrounds the base 162 of the cone 158, and the sealed region 155 of the proximal surface 152 of the plate 150 preferably surrounds the wetting region 153.

[0071] 12A and 12B, in one embodiment, the wetting region 153 of the proximal surface 152 of the plate 150 preferably includes an inner ring 172 including an inner contoured inlet zone 163 that communicates with the proximal end of an inner hole 164 formed in the plate 150. In one embodiment, the inner ring 172, the inner contoured inlet zone 163, and the inner holes 164 are arranged in an annular configuration. The inner holes 164 preferably extend from the distal end of each inner contoured inlet zone 163 toward the distal surface or underside of the plate 150 for passing the polymer melt through the plate.

[0072] In one embodiment, the wetting region 153 of the proximal surface 152 of the plate 150 preferably includes an outer ring 174 including an outer contoured inlet zone 165 that communicates with the proximal ends of outer holes 166 formed in the plate 150. In one embodiment, the outer ring 174, the outer contoured inlet zone 165, and the outer holes 166 are arranged in an annular configuration. The outer holes 166 preferably extend from the distal ends of each of the outer contoured inlet zones 165 toward the distal surface or underside of the plate 150 for extruding a polymer melt through the plate.

[0073] In one embodiment, inner ring 172 preferably surrounds base 162 of cone 158, such that inner contoured inlet zone 163 and inner bore 164 are located within inner ring 172. In one embodiment, outer ring 174 surrounds inner ring 172, such that outer contoured inlet zone 165 and outer bore 166 are located within outer ring 174. In one embodiment, inner ring 172 and outer ring 174 define wetting region 153 of proximal surface 152 of plate 150, and sealed region 155 of proximal surface 152 of plate 150 surrounds wetting region 153.

[0074] 12C and 12D , in one embodiment, the spinneret 106 preferably includes an alignment protrusion 168 extending below and / or projecting from the lower or distal surface 154 of the plate 150. In one embodiment, the alignment protrusion 168 has an outer periphery 170 with a circular configuration that is concentric with the outer periphery 156 of the plate 150 of the spinneret 106. In one embodiment, the outer periphery 170 of the alignment protrusion 168 preferably defines an outer diameter OD4 that is less than the outer diameter OD3 of the plate 150. In one embodiment, the outer diameter OD4 defined by the outer periphery 170 of the alignment protrusion 168 preferably matches the second outer diameter OD2 of the annular upper groove 144 ( FIG. 11B ) formed in the upper surface 138 of the die retainer ring 104. The matching diameters allow the alignment protrusion of the spinneret plate to seat within the annular upper groove of the die retainer ring.

[0075] In one embodiment, the alignment projections 168 have a bottom or distal surface 171. In one embodiment, the spinneret 106 preferably includes inner capillary holes 176A formed in the distal surface 171 with proximal ends in communication with the distal ends of the respective inner holes 164 (FIGS. 12A and 12B), and outer capillary holes 176B formed in the distal surface 171 with proximal ends in communication with the distal ends of the respective outer holes 166 (FIGS. 12A and 12B). In one embodiment, a polymer melt forced into the inner and outer holes of the plate is extruded as a fiber through the respective inner and outer capillary holes 176A, 176B. In one embodiment, the inner and outer capillary holes 176A, 176B are preferably spaced apart from one another in a ring-shaped pattern that matches the spacing pattern of the inner and outer holes 164, 166 (FIGS. 12A and 12B).

[0076] 13A and 13B, in one embodiment, the spinneret 106 preferably includes a plate 150 having a proximal surface 152 and a distal surface 154. The plate 150 preferably has a periphery 156 that defines an outer diameter OD3 of the plate 150 that matches the size and shape of the annular bottom groove formed in the lower or distal end of the die body.

[0077] In one embodiment, an alignment protrusion 168 protruding from the underside of plate 150 preferably extends from distal surface 154 of plate 150. Alignment protrusion 168 includes an outer periphery 170 that desirably defines an outer diameter OD4 that is less than outer diameter OD3 of plate 150. The outer diameter OD4 of alignment protrusion 168 preferably matches the size and shape of an annular upper groove formed in the upper or proximal end of the die retainer ring.

[0078] In one embodiment, the spinneret 106 includes a cone 158 that protrudes above the proximal surface 152 of the plate 150. In one embodiment, the proximal surface 152 of the plate 150 may be a flat, or planar, surface that extends in a horizontal plane. The cone 158 includes an apex 160 and a base 162 having a lower end that is substantially aligned with the plane defined by the proximal surface 152 of the plate 150.

[0079] 13B , in one embodiment, the proximal surface 152 of the plate 150 preferably includes a wetting region 153 and a sealed region 155 surrounding the wetting region 153. In one embodiment, an inner ring 172 and an outer ring 174 are located within the wetting region 153 of the proximal surface 152 of the plate, and the sealed region extends from the outer periphery of the outer ring 174 to the outer periphery 156 of the plate 150. In one embodiment, the spinneret 106 preferably includes an inner ring 172 formed in the wetting region 153 of the proximal surface 152, whereby the inner contoured inlet zone 163, inner hole 164, and inner capillary 176A are associated with the inner ring 172. In one embodiment, the spinneret 106 preferably includes an outer ring 174, which is also formed in the wetted region 153 of the proximal surface 152, whereby the outer contoured inlet zone 165, outer holes 166, and outer capillaries 176B (FIG. 12D) are associated with the outer ring 174. In one embodiment, the inner ring 172 and outer ring 174 are concentric and preferably have an annular or ring shape. The spinneret 106 preferably includes capillary holes 176A and 176B (FIG. 12D) formed in the distal surface 171 of the alignment projection 168. The capillary holes 176A and 176B (FIG. 12D) preferably communicate with the distal ends of the respective inner holes 164 and outer holes 166 (FIG. 12B) formed in the plate 150.

[0080] 14A , in one embodiment, the proximal surface 152 ( FIG. 13B ) of the plate 150 of the spinneret 106 preferably includes a wetted region 153 including an inner ring 172 and an outer ring 174. The inner ring 172 preferably has an annular shape and surrounds the outer periphery of the base 162 of the cone 158 that protrudes above the proximal surface 152 of the plate 150. In one embodiment, an inner contoured inlet zone 163 of each inner hole 164 is formed within the inner ring 172. The inner contoured inlet zone 163 preferably extends below or distally from the proximal surface 152 of the plate so as to communicate with the proximal end of each inner hole 164. In one embodiment, the inner holes 164 are preferably located within the inner ring 172. The inner holes may be drilled. The inner holes 164 are preferably spaced apart from one another and have an array pattern that matches the annular shape of the inner ring 172. The inner bores 164 preferably extend toward and communicate with respective inner capillary bores 176A (FIG. 12C) formed in the bottom or distal surface 171 of the alignment projections 168 (FIG. 13B). The lower or distal ends of the inner bores 164 preferably intersect with the upper or proximal ends of the respective inner capillary bores 176A (FIG. 12C) to direct the polymer melt into the inner capillary bores.

[0081] In one embodiment, inner ring 172 preferably includes inner contoured entrance zones 163 that extend to the proximal ends of the inner holes 164 such that there are substantially no flat or planar surfaces within wetting region 153 that are perpendicular to the direction of the central axes of the distal ends of the holes and / or parallel to the flat proximal surface 152 of the plate of spinneret 106. In one embodiment, inner contoured entrance zones 163 preferably surround the proximal end of each inner hole 164 formed in the plate. In one embodiment, each contoured entrance zone 163 preferably includes a contoured surface that extends distally from proximal surface 152 of plate 150 ( FIG. 13B ) to the proximal end of one of the inner holes 164.

[0082] In one embodiment, within the inner ring 172, the inner contoured inlet zone 163 surrounding the proximal end of each inner hole 164 is immediately adjacent to the inner contoured inlet zone 163 surrounding the proximal end of each adjacent inner hole 164 such that substantially no planar surface perpendicular to the direction of the central axis of the distal end of the hole remains between adjacent holes on the proximal surface 152 of the spinneret plate 150. The contoured surface of the inner contoured inlet zone 163 located around the inner holes 164 may include inclined surfaces and curved surfaces, including concave and convex curved surfaces. In one embodiment, the boundary 175 extending between the inner ring 172 and the outer ring 174 may have a convex curved surface substantially devoid of any flat or planar surfaces perpendicular to the direction of the central axis of the distal end of each hole and / or parallel to the flat proximal surface 152 of the spinneret plate. In one embodiment, boundary 175 is located within the wetted region and may be located distal to and / or below proximal surface 152 of plate 150 .

[0083] In one embodiment, the outer ring 174 is also located within the wetted region 153 of the proximal surface 152 of the plate 150 of the spinneret 106. The outer ring 174 preferably has an annular shape and surrounds the inner ring 172. In one embodiment, an outer contoured inlet zone 165 of each outer hole 166 is formed within the outer ring 174. The outer contoured inlet zone 165 preferably extends below or distal to the proximal surface 152 of the plate so as to communicate with the proximal end of each outer hole 166. In one embodiment, the outer holes 166 are preferably located within the outer ring 174. The outer holes may be drilled. The outer holes 166 are preferably spaced apart from one another and have an array pattern that matches the annular shape of the outer ring 174. The outer holes 166 preferably extend toward respective outer capillary holes 176B (FIG. 12D) formed in the bottom or distal surface 171 of the alignment projections 168 (FIG. 13B). The lower or distal ends of the outer holes 166 preferably intersect with the upper or proximal ends of the respective outer capillary holes 176B (FIG. 12D) to direct the polymer melt into the outer capillary holes.

[0084] In one embodiment, outer ring 174 preferably includes outer contoured inlet zones 165 proximal to the proximal ends of the outer holes 166 such that there are no flat or planar surfaces within wetting region 153 that are perpendicular to the direction of the central axes of the distal ends of the holes and / or parallel to the flat proximal surface 152 of the plate of spinneret 106. In one embodiment, outer contoured inlet zone 165 preferably surrounds the proximal end of each outer hole 166 formed in the plate. In one embodiment, each outer contoured inlet zone 165 preferably includes a contoured surface that extends distally from proximal surface 152 of plate 150 ( FIG. 13B ) to the proximal end of one of the outer holes 166.

[0085] In one embodiment, within the outer ring 174, the outer contoured inlet zone 165 surrounding the proximal end of each outer hole 166 is immediately adjacent to the outer contoured inlet zone 165 surrounding the proximal end of each adjacent outer hole 166 such that no planar surface perpendicular to the direction of the central axis of the distal end of the respective hole remains between adjacent holes on the proximal surface 152 of the spinneret plate 150. The contoured surface of the outer contoured inlet zone 165 extending around the outer holes 166 may include sloped surfaces, as well as curved surfaces, including concave and convex curved surfaces. In one embodiment, the boundary 175 may have a convex curved surface extending between the inner ring 172 and the outer ring 174 and lacking any flat surface parallel to the flat proximal surface 152 of the spinneret plate 150, thereby eliminating dead area from the proximal surface of the spinneret plate.

[0086] 14B and 14C, in one embodiment, inner ring 172 and outer ring 174 are formed in wetted area 153 of proximal surface 152 of plate 150 of spinneret 106. In one embodiment, inner ring 172 and outer ring 174 are recessed and / or located below proximal surface 152 of plate 150 of spinneret 106 (FIG. 12A).

[0087] In one embodiment, the spinneret 106 preferably includes an inner contoured inlet zone 163, inner bores 164, and inner capillary holes 176A associated with the inner ring 172. In one embodiment, the distal end of the inner contoured inlet zone 163 communicates with the proximal end of each inner bore 164, which preferably includes a conical portion 167 that communicates with the proximal end of each inner capillary hole 176A. Accordingly, the inner diameter of the inner bore 164 tapers inward at the conical portion 167 to match the inner diameter of the inner capillary hole 176A. Each inner capillary hole 176A preferably has a central axis A1 extending along the length of the inner capillary hole 176A. In one embodiment, the central axis A1 of the inner capillary hole 176A is preferably perpendicular to the flat, planar surface 152 of the plate 150.

[0088] In one embodiment, the polymer melt is forced into an inner contoured inlet zone 163 located within the inner ring 172, whereupon the polymer melt flows sequentially over the contoured surface of the inner contoured inlet zone 163, through the proximal end of the inner bore 164, through the cone 167 at the distal end of the inner bore 164, and into the proximal end of the inner capillary bore 176A to extrude a fiber from the distal end of the inner capillary bore 176A on the distal side of the spinneret 106. In one embodiment, the inner contoured inlet zone 163 is substantially free of planar or flat surfaces perpendicular to the direction of the central axis A1 of the inner capillary bore 176A, thereby eliminating and / or minimizing the presence of dead areas in the wetted region 153 of the proximal surface 152 of the plate 150.

[0089] In one embodiment, spinneret 106 preferably includes an outer ring 174 formed on the proximal surface 152 of plate 150 of spinneret 106. An outer contoured inlet zone and outer holes 166 are preferably formed in outer ring 174. Outer holes 166 have proximal ends that communicate with the distal end of outer contoured inlet zone 165 and distal ends that communicate with the proximal ends of respective outer capillary holes 176B ( FIG. 12C ) formed in distal surface 171 of spinneret alignment projections 168. Although not shown in FIGS. 14B and 14C , outer contoured inlet zone 165, outer holes 166, and outer capillary holes 176B ( FIG. 12D ) have the same structure and function in a similar manner as described above for inner contoured inlet zone, inner holes for extruding polymer fibers, and inner capillary holes. Thus, in one embodiment, the outer contoured inlet zone 165 has substantially no planar or flat surface perpendicular to the direction of the central axis A1 of the outer capillary hole 176B, thereby eliminating and / or minimizing the presence of dead areas within the wetting region 153 of the proximal surface 152 of the plate 150.

[0090] Referring to FIG. 15 , in one embodiment, an electrical discharge machining (EDM) method may be utilized to shape the geometries of the inner and outer rings, inner and outer contoured inlet zones, inner and outer holes, and inner and outer capillary holes formed in the spinneret plate. In one embodiment, the rings, slots, contoured inlet zones, holes, and capillary holes may be formed in the spinneret plate using a micro-EDM technique, such as that sold by National Jet Company, Inc. of LeVale, Maryland. In one embodiment, the EDM system preferably includes an electrode 180 having a lower surface 182. The lower surface 182 of the electrode 180 preferably has a complex geometry that is utilized to form complex mirror shapes in the spinneret plate. The complex geometry is designed to ensure that the wetted region of the proximal surface of the plate does not have a flat surface that is perpendicular to the direction of the central axes of the respective capillary holes or the direction of the central axes of the distal ends of the holes used to extrude polymer fibers.

[0091] In one embodiment, the electrode 180 can be connected to a power source 184 that forms a recurring electrical discharge to form small, detailed contours or cavities in the plate such that the contoured entrance zones surrounding the proximal ends of the holes have substantially no flat and / or planar surfaces surrounding the proximal ends of the inner and outer holes 164, 166 formed in the respective inner and outer rings 172, 174. By eliminating flat and / or planar surfaces between the holes, the "dead area" between the holes is minimized, avoiding the disassembly problems discussed above in conjunction with the prior art spinnerets shown in Figures 1-5 of this patent application.

[0092] 16A, in one embodiment, spinneret 106 preferably includes a plate 150 having a proximal end 152 and a distal end 154. In one embodiment, inner ring 172 is formed on proximal surface 152 of plate 150. Inner ring 172 is preferably recessed and underlies flat proximal surface 152 of plate 150.

[0093] In one embodiment, outer ring 174 is preferably formed on flat proximal surface 152 of plate 150. Outer ring 174 preferably surrounds inner ring 172. Outer ring 174 preferably defines a recess or groove that is located below proximal surface 152 of plate 150. In one embodiment, inner ring 172 and outer ring 174 are preferably located within wetting region 153 of proximal surface 152 of plate 150, and proximal surface 152 of plate 150 includes a sealed region 155 that surrounds wetting region 153.

[0094] 16B-16D, in one embodiment, an array of inner holes 164 is preferably formed (e.g., drilled, EDMed) in inner ring 172 and extends toward bottom or distal surface 171 of alignment projections 168 that extend below distal surface 154 of plate 150 of spinneret 106. In one embodiment, inner capillary holes 176A are formed in bottom surface 171 of alignment projections 168. Inner capillary holes 176A preferably have upper or proximal ends that intersect with lower or distal ends of each inner hole 164. The distal ends of inner holes 164 preferably taper inwardly via conical portions 167A that communicate with the proximal ends of inner capillary holes 176A.

[0095] In one embodiment, outer holes 166 are preferably formed in outer ring 174 of spinneret 106. Outer holes 166 preferably extend toward distal surface 171 of alignment protrusion 168, which extends below distal surface 154 of plate 150 of spinneret 106. In one embodiment, outer capillary holes 176B are formed in distal surface 171 of alignment protrusion 168 of spinneret 106. Outer capillary holes 176B preferably have upper or proximal ends that communicate with lower or distal ends of respective outer holes 166 located in outer ring 174 of spinneret 106. The distal ends of outer holes 166 preferably taper inwardly via conical portions 167B that communicate with proximal ends of outer capillary holes 176B.

[0096] 16D, in one embodiment, each inner capillary hole 176A preferably has a central axis A1 extending along the length of the inner capillary hole 176A. In one embodiment, the inner contoured inlet zone 163 has sloped, contoured, flat, and / or planar surfaces, whereby none of the sloped, contoured, flat, and / or planar surfaces within the inner contoured inlet zone 163 are perpendicular to the central axis A1 of the inner capillary hole 176A.

[0097] In one embodiment, each outer capillary hole 176B preferably has a central axis A2 extending along the length of the outer capillary hole 176B. In one embodiment, the outer contoured inlet zone 165 has sloped, contoured, flat, and / or planar surfaces, whereby none of the sloped, contoured, flat, and / or planar surfaces in the outer contoured inlet zone 165 are perpendicular to the central axis A2 of the outer capillary hole 176B.

[0098] 17A and 17B , in one embodiment, to assemble the polymer extrusion die assembly 100, the spinneret 106 is preferably positioned between the lower or distal end 116 of the die body 102 and the upper or proximal end 136 of the die retainer ring 104. In one embodiment, the distal surface 154 of the plate 150 of the spinneret 106 is preferably seated within the annular upper groove 144 formed in the flat upper surface 138 of the die retainer ring 104. The outer periphery 156 of the plate 150 of the spinneret 106 is preferably seated within the annular bottom groove 124 formed in the bottom surface 118 of the die body 102. The cone 158 of the spinneret 106 is preferably positioned within the polymer melt exit opening 126 of the die body 102. The outer sloped wall of the cone 158 is preferably spaced from the sloped sidewall 134 of the polymer melt exit opening 126. The outer surface of the cone 158 and the sloped sidewall 134 of the polymer melt exit opening 126 preferably define a polymer melt channel 185 that extends along the side of the cone 158 and has a lower end that intersects with inner and outer rings 172, 174 located within the wetting region 153 ( FIG. 13B ) of the proximal surface 152 of the plate 150. The polymer melt channel 185 preferably directs the polymer melt toward the wetting region of the proximal surface 152 of the plate 150.

[0099] In one embodiment, as the polymer melt is fed into the inlet opening 108 formed in the top surface 114 of the die body 102, it preferably passes through the restricted flow region 132 of the flow path and then through a polymer melt flow channel 185 extending between the cone 158 and the sloped sidewall 134 of the polymer melt exit opening 126. The polymer melt is preferably forced into inner and outer contoured inlet zones that communicate with the proximal ends of the respective inner and outer holes 164, 166 (FIG. 16D) formed in the respective inner and outer rings 172, 174 of the spinneret plate 150, and then extruded through the respective inner and outer capillary holes 176A, 176B (FIG. 16D) formed in the distal surface 171 of the alignment protrusion 168 extending from the distal surface of the plate 150 of the spinneret 106.

[0100] In one embodiment, fastening bolts (not shown) may be inserted into bolt holes 148A-148D (FIG. 10B) formed in the top surface of the die retaining ring 104 and bolt holes 128A-128D (FIG. 8D) formed in the bottom surface of the die body 102 to align the die body 102 and the die retaining ring 104 with respect to one another and to hold the components of the polymer extrusion die assembly 100 together during the fiber extrusion process.

[0101] In one embodiment, the spinneret can have a single ring of spaced apart holes designed to extrude a polymer melt to form polymer fibers. In one embodiment, the spinneret has 28 spaced apart holes. In another embodiment, the single ring of spaced apart holes can be positioned within a preformed slot or ring-shaped groove.

[0102] 18A-18D, in one embodiment, a 28-hole spinneret 206 preferably includes a plate 250 having a top or proximal surface 252 and a bottom or distal surface 254. The spinneret 206 may incorporate one or more of the structural features shown and described above in the embodiments shown in FIGS. 12A-12D, 13A-13B, 14A-14C, and 16A-16D. In one embodiment, the plate 250 may have an annular or circular shape. In one embodiment, the plate 250 preferably has an outer periphery 256 defining an outer diameter OD5 that substantially corresponds to the outer diameter OD1 of the annular bottom groove 124 (FIG. 8D) formed in the distal end of the die body 102.

[0103] 18A and 18B, in one embodiment, spinneret 206 preferably includes a cone 258 that protrudes above proximal surface 252 of plate 250. Cone 258 desirably includes a top portion 260 that is adapted to be inserted into polymer melt exit opening 126 (FIG. 9B) located at the distal end of die body 102. Cone 258 preferably includes a base portion 262 at its lower end that is substantially aligned with the plane defined by flat proximal surface 252 of spinneret 206.

[0104] 18A-18D, in one embodiment, spinneret 206 preferably includes a ring 272 having an annular or circular configuration extending around base 262 of cone 258. Spinneret 206 preferably includes contoured inlet zones 263 disposed within ring 272 and in communication with proximal ends of holes 264 extending through plate 250 for passing the polymer melt through the plate. In one embodiment, holes 264 are preferably spaced apart from one another within ring 272, with one of the contoured inlet zones 263 surrounding each hole 264.

[0105] 18C and 18D , in one embodiment, the spinneret 206 preferably includes an alignment protrusion 268 extending below and / or projecting from the distal surface 254 of the plate 250. In one embodiment, the alignment protrusion 268 has an outer periphery 270 with a circular configuration that is concentric with the outer periphery 256 of the plate 250 of the spinneret 206. In one embodiment, the outer periphery 270 of the alignment protrusion 268 preferably defines an outer diameter OD6 that is less than the outer diameter OD5 of the plate 250. In one embodiment, the outer diameter OD6 defined by the outer periphery 270 of the alignment protrusion 268 preferably matches the second outer diameter OD2 of the annular upper groove 144 ( FIG. 11B ) formed in the upper surface 138 of the die retainer ring 104. The matching diameters allow the alignment protrusion 268 to seat within the annular upper groove of the die retainer ring.

[0106] In one embodiment, the spinneret 106 preferably includes capillary holes 276 formed in the distal surface 271 of the alignment projections 268. The capillary holes preferably have proximal ends that intersect with distal ends of the contoured inlet zone 263 and spaced apart holes 264 (FIG. 18A and 18B) for receiving the polymer melt that is fed into the contoured inlet zone 263 and the spaced apart holes 264 (FIG. 18B).

[0107] 19A and 19B, in one embodiment, the spinneret 206 preferably includes a plate 250 having a proximal surface 252 and a distal surface 254. The plate 250 preferably has a periphery 256 that defines an outer diameter OD5 of the plate 150.

[0108] In one embodiment, alignment projection 268 preferably extends from distal surface 254 of plate 250. Alignment projection 268 desirably includes a periphery 270 that defines an outer diameter OD6 that is less than outer diameter OD5 of plate 250.

[0109] In one embodiment, spinneret 206 includes a cone 258 that protrudes above proximal surface 252 of plate 250. In one embodiment, proximal surface 252 of plate 250 is flat, planar, and / or extends in a horizontal plane. Cone 258 includes an apex 260 and a base 262 having a lower end that is substantially aligned with the plane defined by proximal surface 252 of plate 250.

[0110] 19B-19D , in one embodiment, ring 272 is preferably located within wetted region 253 of proximal surface 252 of plate 250. In one embodiment, ring 272 is annular or ring-shaped and extends around base 262 of cone 258. Spinneret 206 preferably includes a contoured inlet zone 263 located within ring 272. Contoured inlet zone 263 extends distally from proximal surface 252 of plate 250 and preferably has a distal end in communication with the proximal end of hole 264 extending through the plate. Hole 264 has a distal end including a conical portion 267 that tapers inward to the proximal end of capillary hole 276, which extends to the bottom or distal surface 271 of alignment protrusion 268.

[0111] In one embodiment, spinneret 206 preferably includes a contoured entrance zone 263 that extends distally to the proximal end of holes 264, which ensures that there is no flat surface that is parallel to flat proximal surface 252 of the plate of spinneret 206. In one embodiment, each contoured entrance zone 263 preferably includes a contoured surface that extends from proximal surface 252 of plate 250 to the proximal end of each hole 264.

[0112] In one embodiment, the contoured inlet zone 263 surrounding each hole 264 is immediately adjacent to the contoured inlet zone surrounding each adjacent hole such that no planar and / or flat surfaces remain between adjacent holes extending through the spinneret plate. The contoured surfaces around the holes 264 can include angled surfaces and curved surfaces, including concave and convex curved surfaces.

[0113] 19C and 19D , in one embodiment, each capillary hole 276 preferably has a central axis A3 that extends along the length of the capillary hole 276. In one embodiment, the contoured inlet zone 263 has sloped, contoured, flat, and / or planar surfaces, whereby none of the sloped, contoured, flat, and / or planar surfaces within the contoured inlet zone 263 are perpendicular to the central axis A3 of the capillary hole 276.

[0114] In one embodiment, the spinneret can have a single annular ring formed on the proximal surface of the plate and a plurality of contoured inlet zones and spaced apart holes formed in the annular ring for extruding the polymer melt. In one embodiment, the spinneret can have 24 contoured inlet zones and 24 holes (one hole associated with each contoured inlet zone), which are spaced apart from one another within the single annular ring.

[0115] 20A-20D, in one embodiment, a 24-hole spinneret 306 preferably includes a plate 350 having a top or proximal surface 352 and a bottom or distal surface 354. Plate 350 may have an annular or circular shape. Plate 350 preferably has an outer periphery 356 defining an outer diameter OD7 that substantially matches the outer diameter OD1 of annular bottom groove 124 (FIG. 8D) at the distal end of die body 102.

[0116] 20A and 20B, in one embodiment, spinneret 306 preferably includes a cone 358 that protrudes above proximal surface 352 of plate 350. Cone 358 desirably includes a top portion 360 that is adapted to be inserted into the hollow cone of polymer melt exit opening 126 (FIG. 9B) located at the distal end of die body 102. Cone 358 preferably includes a base portion 362 at its lower end that is substantially aligned with the plane defined by the flat proximal surface 352 of spinneret 306.

[0117] 20A-20D, in one embodiment, spinneret 306 preferably includes a ring 372 having an annular configuration that surrounds base 362 of cone 358. In one embodiment, spinneret 306 preferably includes contoured inlet zones 363 located within ring 372. Each contoured inlet zone 363 is preferably associated with a hole 364 extending through plate 350 for passing the polymer melt through the plate. In one embodiment, the contoured inlet zones extend toward distal surface 354 of plate 350 and have distal ends that communicate with proximal ends of the respective holes 364.

[0118] 20C and 20D , in one embodiment, the spinneret 306 preferably includes an alignment protrusion 368 extending below and / or projecting from the distal surface 354 of the plate 350. In one embodiment, the alignment protrusion 368 has an outer periphery 370 with a circular configuration that is concentric with the outer periphery 356 of the plate 350 of the spinneret 306. In one embodiment, the outer periphery 370 of the alignment protrusion 368 preferably defines an outer diameter OD8 that is less than the outer diameter OD7 of the plate 350. In one embodiment, the outer diameter OD8 defined by the outer periphery 370 of the alignment protrusion 368 preferably matches the second outer diameter OD2 of the annular upper groove 144 ( FIG. 11B ) formed in the upper surface 138 of the die retainer ring 104. The matching diameters allow the alignment protrusion 368 to seat within the annular upper groove of the die retainer ring.

[0119] In one embodiment, the spinneret 306 preferably includes capillary holes 376 formed in the distal surface 371 of the alignment projections 368. The capillary holes have proximal ends that intersect with the distal ends of the spaced holes 364 (FIGS. 20A and 20B) for receiving the polymer melt delivered through the spaced holes.

[0120] 21A and 21B, in one embodiment, the spinneret 306 preferably includes a plate 350 having a proximal surface 352 and a distal surface 354. The plate 350 preferably has a periphery 356 that defines an outer diameter OD7 of the plate 250.

[0121] In one embodiment, alignment projection 368 preferably extends from distal surface 354 of plate 350. Alignment projection 368 desirably includes a periphery 370 that defines an outer diameter OD8 that is less than outer diameter OD7 of plate 350.

[0122] In one embodiment, spinneret 306 preferably includes a cone 358 that protrudes above proximal surface 352 of plate 350. In one embodiment, proximal surface 352 of plate 350 is flat and / or extends in a horizontal plane. Cone 358 includes an apex 360 and a base 362 having a lower end that is substantially aligned with the plane defined by proximal surface 352 of plate 350.

[0123] 21B-21D, in one embodiment, the holes 364 formed in the plate (e.g., by drilling using EDM) are preferably located within a ring 372 formed in the proximal surface 352 of the plate 350. In one embodiment, the ring 372 is annular or ring-shaped and extends around the base 362 of the cone 358. The ring 372 is preferably recessed relative to the proximal surface 352 of the plate 350. The spinneret 306 preferably includes capillary holes 376 formed in the bottom surface 371 of the alignment projection 368. The capillary holes 376 preferably communicate with the distal ends of each of the holes 364 formed in the plate 350. The distal ends of the holes 364 preferably include a tapered conical surface 367 that tapers inwardly to the proximal ends of the capillary holes 376. In one embodiment, the capillary holes 367 preferably have a length that extends along the longitudinal axis A4.

[0124] In one embodiment, ring 372 preferably includes a contoured inlet zone 363 that extends distally to the proximal end of each hole 364 extending through spinneret plate 350. Contoured inlet zone 363 preferably includes a contoured, sloped, flat, and / or planar surface, any of which is perpendicular to central axis A4 extending along the length of each capillary hole 376. In one embodiment, contoured inlet zone 363 preferably surrounds the proximal end of each outer hole 364 formed in the plate.

[0125] In one embodiment, the contoured entrance zone 363 of each hole 364 is immediately adjacent to the contoured entrance zone of each adjacent hole such that no planar and / or flat surfaces remain between adjacent holes in the wetted region of the proximal surface 352 of the spinneret plate 350. The contoured entrance zone 363 around the holes 364 can include angled surfaces and curved surfaces, including concave and convex curved surfaces.

[0126] Figure 22 illustrates the flow velocity profile of the polymer melt as it flows through and over the wetting region of the spinneret 206 shown in Figures 18A-18D and 19A-19D and described above. The polymer melt flow velocity distribution is significantly more uniform, as evidenced by much less stagnant flow (i.e., the dark blue region) within the wetting region than the flow velocity profiles achieved using the prior art spinnerets shown in Figures 1-2 and 3-4 of the present patent application. Thus, the "dead area" of the inventive spinneret 206 of Figures 18A-18D and 19A-19D is relatively small, preferably about 12% or less, compared to the 90% "dead area" of the prior art spinneret shown in Figures 1 and 2 and the 43% or so "dead area" of the spinneret shown in Figures 3 and 4.

[0127] The breaker plate is a component that directs the polymer melt toward the proximal end of the die body of a polymer extrusion die assembly. The breaker plate is adapted to receive a filtration component, such as a filter screen. The breaker plate can also be designed to include one or more mixing elements, such as ball bearings, positioned within a hollow cylindrical wall that protrudes proximally from the proximal surface of the breaker plate.

[0128] 23A and 23B, a conventional breaker plate 80 includes a cylinder 82 defining a cylindrical hollow space 84 adapted to receive a filtering component, such as a filter screen. The breaker plate 80 has holes 86 through which the polymer melt flows. The proximal surface of the breaker plate has flat surfaces 88 located between the holes 86. The flat surfaces 88 are also located on the periphery 90 of the proximal surface of the plate. The flat surfaces 88, which comprise approximately 78.1% of the surface area of ​​the proximal surface of the plate, define dead zones where the polymer melt cannot flow freely through the breaker plate 80. As the polymer melt flows through the breaker plate 80, the flowing polymer stagnates in the dead zones, which can lead to degradation of the polymer melt and the formation of weak sutures.

[0129] 24 shows filtering elements 94A-94E (e.g., filtering screens) disposed in the cylindrical hollow space 84 of the breaker plate 80 and in the holes 86 formed in the breaker plate to cover the proximal surface of the breaker plate 80. The filtering elements 94A-94E are designed to remove impurities present in the polymer melt.

[0130] Figure 25A shows a die body 96 of a polymer extrusion die assembly. The die body 96 has an inlet opening 98 at its proximal end that is adapted to receive the polymer melt after it passes through the breaker plate 80 (Figure 24). Referring to Figure 25B, the breaker plate 80 (Figure 24) is assembled with the die body 96 such that the cylinder 82 of the breaker plate 80 is aligned with the inlet opening 98 (Figure 25A) of the die body 96. One or more mixing elements 99, such as stainless steel ball bearings, may be disposed within the cylindrical hollow space 84 (Figure 24) of the breaker plate 80 to mix the polymer melt as it passes through the breaker plate.

[0131] As described above, conventional breaker plates have flat surfaces and / or dead zones on their proximal surfaces, which can cause the polymer melt to break down as it flows through a polymer extrusion die assembly. Several efforts have been made to minimize the presence of dead zones between breaker plate holes. For example, U.S. Patent Nos. 3,938,925 and 5,650,067 disclose breaker plates in which the inlets to the flow holes are enlarged toward the central region of the breaker plate to eliminate the presence of dead zones. Despite these advances, conventional breaker plates still have a significant number of flat surfaces located along the corners and / or along the periphery of the proximal surface of the breaker plate. Furthermore, the inlets for the polymer melt flow holes or flow channels typically have ridges defining their tips, which cannot adequately support a filtering element (e.g., a filtering screen) when under high pressure during a polymer extrusion process.

[0132] Therefore, despite the above efforts, there remains a need for an improved breaker plate that substantially eliminates dead zones at the proximal surface of the breaker plate to minimize polymer degradation. There remains a need for a breaker plate that has a structure to adequately support the filter without risking the filter collapsing and / or deforming under high pressure.

[0133] 26A and 26B, in one embodiment, a polymer extrusion die assembly 400 preferably includes a die body 402, a die retainer ring 404, a spinneret 406, a breaker plate 480, and a filtration element 485. The polymer extrusion die assembly 400 is preferably adapted to receive a polymer melt at its proximal end and dispense filaments or fibers from its distal end, whereby the extruded fibers can be used to make sutures. The die body 402, the die retainer ring 404, and the spinneret 406 can have one or more of the structural features disclosed in other embodiments disclosed in this patent application. For example, the die body 402 can be similar to the die body 102 shown in Figures 8A-8D and 9A-9B and described above, the die retainer ring 404 can be similar to the die retainer ring 104 shown in Figures 10A-10D and 11A-11B and described above, and the spinneret 406 can be similar to the spinneret 106 shown in Figures 12A-14C, the spinneret 206 shown in Figures 18A-19D, and / or the spinneret 306 shown in Figures 20A-21D.

[0134] In one embodiment, the die body 402 preferably includes a proximal end 412 having a flat top surface 414 and a distal end 416 having a flat bottom surface 418. The proximal end 412 of the die body 402 desirably includes a proximal inlet opening 408 for directing the polymer melt into the proximal end of the die body. In one embodiment, the die body 402 of the polymer extrusion die assembly 400 preferably includes an upper groove 420 having an annular shape formed in the die body's top surface 414 and surrounding the proximal opening 408 of the polymer extrusion die assembly 400.

[0135] In one embodiment, the breaker plate 480 is seated in the upper groove 420 located at the proximal end of the die body 402. In one embodiment, the breaker plate 480 is preferably positioned within the polymer flow path and is located between the polymer outlet of the pump block (not shown) and the inlet opening 408 of the die body 402. In one embodiment, the breaker plate 480 preferably mixes, homogenizes, and / or filters the polymer melt before it flows into the inlet opening 408 of the die body 402.

[0136] 27A-27E , in one embodiment, breaker plate 480 preferably includes a cylinder 482 defining a cylindrical hollow space 484 adapted to receive a filtering and / or mixing component. The filtering component may include a filtering screen, and the mixing component may include a plurality of ball bearings (e.g., stainless steel ball bearings). Breaker plate 480 preferably has a plurality of flow holes 486 formed therein that are spaced apart from one another and extend between a proximal (inlet) surface 452 and a distal (outlet) surface 455 of the plate to allow the polymer melt to flow through the breaker plate. In one embodiment, each flow hole 486 preferably has a proximal end, a distal end, and a central axis A5 extending from the proximal end to the distal end. In one embodiment, the central axis A5 may be perpendicular to a plane defined by the respective proximal and distal surfaces 442 and 445 of the breaker plate.

[0137] In one embodiment, breaker plate 480 may have 10-100 flow holes 486. In one embodiment, each flow hole 486 may have an inner diameter of about 1-4 mm and a depth of about 5-10 mm to allow polymer melt to flow from the outlet of a polymer source, such as a metering pump block (not shown), to the inlet of extrusion die assembly 400 (FIG. 26A).

[0138] 27A-27E and 28 , in one embodiment, the proximal surface 452 of the breaker plate 480 preferably includes a wetted region 453 that includes spaced-apart flow holes 486. In one embodiment, the breaker plate 480 desirably includes a contoured inlet zone 463 that surrounds and is in communication with the proximal end of each respective flow hole 486. In one embodiment, each contoured inlet zone 463 preferably includes a contoured surface that extends distally from the proximal surface 452 of the plate 480 to the proximal end of each associated flow hole 486. In one embodiment, each proximal contoured inlet zone 463 preferably does not have substantially a planar or flat surface perpendicular to the central axis of the associated flow hole.

[0139] In one embodiment, the contoured inlet zone 463 surrounding the proximal end of each flow hole 486 is immediately adjacent to the contoured inlet zone 463 surrounding the proximal end of each adjacent flow hole 486 such that substantially no planar surface perpendicular to the direction of the central axis A5 of the respective flow hole 486 remains between adjacent holes on the proximal surface 452 of the breaker plate 480. The contoured surfaces of the contoured inlet zone 463 may include angled surfaces and curved surfaces, including concave and convex curved surfaces.

[0140] In one embodiment, the proximal side of the breaker plate desirably includes a ridge 475 that preferably surrounds the contoured inlet zone 463. The ridge 475 may have a convex curved surface that is substantially devoid of any flat or planar surface that is perpendicular to the direction of the central axis A5 of each flow hole 486. In one embodiment, the ridge 475 is coplanar on the proximal surface 452 of the breaker plate 480 (e.g., the proximal surface 452 of the plate). In one embodiment, the ridge 475 preferably contacts and supports the distal face of the filtering element 485 ( FIG. 26A ) to minimize the risk of deformation of the filtering element when the filtering element is subjected to high pressures during the extrusion process.

[0141] In one embodiment, breaker plate 480 preferably includes distal surface 455 and a contoured exit zone 473 formed in distal surface 455 surrounding the distal end of each flow hole 486. Contoured exit zone 473 preferably extends between the distal ends of flow holes 486 and distal surface 455 of the plate. Contoured exit zone 473 preferably has substantially no flat surfaces perpendicular to the central axis A5 of each flow hole. The contoured entrance zone 463 formed in the proximal surface of the breaker plate and the contoured exit zone 473 formed in the distal surface of breaker plate 480 desirably provide a breaker plate without dead zones, which desirably minimizes polymer degradation, improves fiber uniformity, and significantly increases the strength of the formed fiber or suture.

[0142] In one embodiment, the contoured inlet zone 463 and the contoured outlet zone 473 have substantially no planar or flat surfaces perpendicular to the direction of the central axis A5 of the respective flow holes 486, thereby eliminating and / or minimizing the presence of dead areas within the wetted regions of the proximal surface 452 and the distal surface 455 of the breaker plate 480.

[0143] In one embodiment, after the breaker plate 480 is positioned between a pump block (not shown) and the proximal end of the die body 402 (FIG. 26A), the polymer melt can be forced into the proximal end of the breaker plate 480, and then the polymer melt flows sequentially into the cylindrical hollow space 484, over the contoured inlet zone 463, through the flow holes 486, over the contoured outlet zone 473, and into the inlet opening 408 of the die body 402 (FIG. 26A).

[0144] The breaker plate 480 preferably has a hollow space 484 inside the tubular wall 482 that is directly connected to the proximal surface 452 of the plate. In one embodiment, polymer mixing and / or filtering elements, such as stainless steel balls, sintered and / or wire mesh screens, may be held within the hollow space 484 to homogenize the polymer melt and / or filter impurities from the polymer stream. The tubular wall 482 of the breaker plate 480 has an outer diameter OD9 of about 2-5 cm, a wall thickness T1 of 2-8 mm, a height H1 of about 1-4 cm, and an outer diameter OD2 of about 2-5 cm. 10 The inner diameter ID1 may be equal to

[0145] In one embodiment, the tubular wall 482 has a proximal surface 485 and a distal surface 495 that can function as a sealing surface when the breaker plate is installed in a polymer passage line. The distal surface 455 of the breaker plate 480 can be slightly recessed relative to the distal sealing surface 495.

[0146] 29A-29C, in one embodiment, a breaker plate 480 is preferably assembled with the inlet opening 408 of the die body 402. The die body includes an annular groove 420 surrounding the inlet opening 408, which is adapted to seat a distal sealing surface 495 at the distal end of the cylindrical wall 482 of the breaker plate. FIG. 29A shows the breaker plate 480 before it is seated in the annular groove 420 of the die body 402. FIGS. 29B and 29C show the breaker plate 480 after it is seated in the annular groove 420 of the die body 402. The hole 486 in the breaker plate is preferably aligned with the inlet opening 408 of the die body 402.

[0147] 30A-30C , in one embodiment, a breaker plate 480 is assembled with the inlet opening 408 at the proximal end 412 of the die body 402 of the polymer extrusion die assembly 400, and a filtering element 485, such as a filtering screen, can be inserted into a cylindrical hollow space 484 surrounded by the cylindrical wall 482 of the breaker plate 480. In one embodiment, the filtering element 485 preferably has an outer diameter that substantially matches the inner diameter of the cylindrical wall 482 such that the filtering element 485 completely covers the proximal surface 452 of the breaker plate 480, as well as the contoured inlet zone 463 and flow holes 486 of the breaker plate.

[0148] Conventional conical die bodies remain inadequate because they typically have a large hollow space in the upper region of the conical die body. For example, Figure 31 shows a conventional die body with a large hollow conical space in the upper region of the die body, which causes slow polymer flow rate and longer residence time, which can lead to undesirable polymer degradation resulting in weak or broken filaments.

[0149] Another problem with conventional conical die bodies is poor heat transfer between the die body and the polymer melt flowing through it. Die zone temperatures are typically set and controlled to optimal specifications for fiber extrusion. The inlet polymer temperature depends on the temperature of the polymer source provided from the extruder or pump block, which is typically set at a temperature different from the die body temperature. As a result, the temperature of the polymer melt from the polymer source can be significantly lower or higher than the die body temperature. Insufficient heat transfer between the die body and the polymer melt prevents the polymer melt stream from achieving a uniform equilibrium melt temperature before entering the spinneret capillary holes, resulting in non-uniform fiber structure and / or other defects.

[0150] Figure 32 shows the results of a simulation in which the source polymer from the pump block is approximately 235°C as it enters the inlet of the conical die body. The temperature of the bulk of the polymer remains nearly unchanged throughout the inverted cone space. The polymer temperature increases rapidly only after reaching the bottom of the die body, and the polymer melt stream splits into thin layers along the polymer melt flow passage formed between the central cone of the die / spinneret and the hollow cone space of the die body. As a result of less than optimal heat transfer, it is difficult to heat the polymer melt to the desired equilibrium temperature of 250°C, the desired extrusion temperature of the die body.

[0151] In view of the above-mentioned deficiencies in the die body disclosed in FIGS. 31 and 32, several efforts have been made to improve heat transfer between the die body and the polymer melt flowing therethrough. For example, U.S. Patent Application Publication No. 2002 / 0107326 discloses adding a cone downstream of the breaker plate, with the tip of the cone extending downstream away from the breaker plate. Flow channels are drilled through the central disk of the breaker plate, including the cone. The conical central disk is designed to reduce downstream flow rate by occupying a portion of the hollow space of the inverted cone in the die adapter. Unfortunately, because the temperature of the conical central disk is essentially the same as the temperature of the source polymer entering the die body, heat transfer between the polymer stream and the die body or die adapter is not improved. As a result, heat is not easily transferred to or from the die adapter assembly, making it difficult to precisely control the temperature necessary to achieve optimal, uniform, and stable fiber extrusion.

[0152] U.S. Patent No. 4,072,457 discloses a spinning pot for extruding fibers using polymer delivery channels drilled in a branched fashion in the top cap. The top cap has a smaller total flow volume than a top cap with an inverted conical hollow space, through which the polymer flows from a small inlet to a breaker plate with an increased diameter. The system disclosed in the '457 patent reduces the average residence time due to the reduced free volume within the top cap, but a significant amount of flat surface exists on the outlet side of the top cap. The flat surface is perpendicular to the axis of the flow channels in the breaker plate below the top cap. As a result, polymer at or near the flat surface of the top cap tends to stagnate or flow at a much slower rate than it would flow into the holes in the breaker plate near the outlets of the branched polymer delivery channels in the top cap. In addition to the potentially slower velocity, the melt flow path is significantly longer through holes near the center region of the breaker plate, where the outlets of the delivery channels are located, than through holes near the periphery. Therefore, the residence time of the polymer passing through the spin pot varies significantly between holes at different locations across the top cap, and longer residence times will generally result in polymer degradation, poor fiber uniformity, and / or poor tensile strength properties.

[0153] Therefore, despite the above efforts, there remains a need for improved designs for die bodies that have reduced free volume, improved heat exchange characteristics, and good homogeneity in the polymer melt stream before the polymer enters the capillary holes of the extrusion die / spinneret.

[0154] 33A and 33B, in one embodiment, a polymer extrusion die assembly 500 preferably includes a die body 502, a spinneret 506, a tubular adapter 580, and a filtration element 585. The polymer extrusion die assembly 500 is preferably adapted to receive a polymer melt at its proximal end and dispense filaments or fibers from its distal end, whereby the extruded fibers can be used to make sutures. The die body 502 and the spinneret 506 can have one or more of the structural features described in other embodiments disclosed in this patent application. For example, the die body 502 may have one of the structural features similar to the die body 102 shown in Figures 8A-8D and 9A-9B and described above, and the spinneret 506 may be similar to the spinneret 106 shown in Figures 12A-14C, the spinneret 206 shown in Figures 18A-19D, and / or the spinneret 306 shown in Figures 20A-21D.

[0155] In one embodiment, the die body 502 preferably includes a proximal end 512 having a flat top surface 514 and a distal end 516 having a flat bottom surface 518. The proximal end 512 of the die body 502 desirably includes a proximal inlet opening 508 for directing the polymer melt into the proximal end of the die body. In one embodiment, the die body 502 of the polymer extrusion die assembly 500 preferably includes an upper groove 520 having an annular shape formed in the die body's top surface 514 and surrounding the inlet opening 508 of the polymer extrusion die assembly 500.

[0156] In one embodiment, the distal end 516 of the die body 502 has a conical opening 526 adapted to receive the cone 558 of the spinneret 506 when the spinneret is assembled with the distal end of the die body 502.

[0157] In one embodiment, the tubular adapter 580 is adapted to seat in the annular upper groove 520 located at the proximal end 512 of the die body 502. In one embodiment, the tubular adapter 580 is preferably positioned within the polymer flow path and is located between the polymer outlet of the pump block (not shown) and the inlet opening 508 of the die body 502. In one embodiment, the tubular adapter 580 can receive components for mixing, homogenizing, and / or filtering the polymer melt before it flows into the inlet opening 508 of the die body 502. In one embodiment, a filtration element 585 is positioned inside the tubular element 580 to cover the inlet opening 508 at the proximal end 512 of the die body 502.

[0158] 34A-34F , in one embodiment, the die body 502 preferably includes a plurality of flow channels 586 extending between an inlet opening 508 at the proximal end 512 of the die body 502 and a conical opening 526 formed in a flat surface 518 at the distal end 516 of the die body 502. In one embodiment, the die body 502 desirably includes approximately 3 to 60 flow channels 586 extending between the inlet opening 508 and the conical opening 526. In one embodiment, the inlet opening 508 of the die body 502 preferably includes a plurality of contoured inlet zones 563 communicating with the proximal ends of the respective flow channels 586. The inlet opening 508 desirably includes ridges 575 extending between the contoured inlet zones 563, whereby the ridges 575 preferably lie in a common plane 552. Due to the presence of the contoured inlet zone 563 at the inlet opening 508 of the die body 502, there are essentially no flat surfaces located between the proximal ends of each flow channel 586 within the area of ​​the inlet opening.

[0159] 34E and 34F, in one embodiment, the distal end of the flow channel 586 preferably communicates with a conical opening 526 formed in the distal face 518 of the die body 502.

[0160] 34E-34F and 35, in one embodiment, the inlet opening 508 of the die body 502 preferably includes a wetting region 553 including a contoured inlet zone 563 surrounding and in communication with the proximal end of each of the respective flow channels 586. In one embodiment, each contoured inlet zone 563 preferably includes a contoured surface extending distally from a common plane 552 extending across the width of the inlet opening 508. The contoured inlet zone preferably extends distally to the proximal end of each flow channel 586 associated therewith. In one embodiment, each contoured inlet zone 563 preferably does not have substantially a planar or flat surface perpendicular to the central axis A6 of the respective flow channel 586 associated therewith.

[0161] In one embodiment, the contoured inlet zone 563 surrounding the proximal end of each flow channel 586 is immediately adjacent to the contoured inlet zone 563 surrounding the proximal end of each adjacent flow channel 586 such that substantially no planar surface perpendicular to the direction of the central axis A6 of the respective flow channel 586 remains between adjacent channels in the common plane 552 of the inlet opening 508 of the die body 502. The contoured surfaces of the contoured inlet zone 563 can include angled surfaces and curved surfaces, including concave and convex curved surfaces.

[0162] In one embodiment, inlet opening 508 of die body 502 preferably includes a ridge 575 that preferably surrounds contoured inlet zone 563. Ridge 575 may have a convex curved surface that is substantially devoid of any flat or planar surface that is perpendicular to the direction of central axis A6 of each flow channel 586. In one embodiment, ridge 575 lies within a common plane 552 ( FIG. 34E ) that extends across the width of inlet opening 508 of die body 502. In one embodiment, ridge 575 preferably contacts and supports the distal face of filtration element 585 ( FIG. 33A ) to minimize the risk of deformation of the filtration element when it is subjected to high pressures during the extrusion process.

[0163] In one embodiment, the contoured inlet zone 563 has substantially no planar or flat surfaces perpendicular to the direction of the central axis A6 of each flow channel 586, thereby eliminating and / or minimizing the presence of dead areas within the wetted region 553 of the inlet opening 508 of the die body 502.

[0164] 36A-36C, in one embodiment, the polymer extrusion die assembly 600 (FIG. 33A) can include a tubular adapter 580 adapted to be disposed between a pump block (not shown) and the proximal end 512 (FIG. 33A) of the die body 502, where the polymer melt can be forced into an inlet opening at the proximal end of the tubular adapter 580.

[0165] In one embodiment, tubular adapter 580 preferably includes a tubular wall 582 that surrounds a hollow space 584. In one embodiment, polymer mixing and / or filtering elements, such as stainless steel balls, sintered and / or wire mesh screens, may be retained within hollow space 584 to homogenize the polymer melt and / or filter impurities from the polymer stream. In one embodiment, tubular wall 582 preferably has a proximal surface 585 and a distal surface 595 that may function as sealing surfaces when tubular adapter 580 is installed in a polymer passage line.

[0166] In one embodiment, the tubular wall 582 of the tubular adapter 580 has an outer diameter OD of approximately 2-5 cm, which is equal to the inner diameter of the annular groove 520 (FIG. 33A) surrounding the inlet opening 508 of the die body 502. x The tubular wall 582 may have a wall thickness T2 of about 2-8 mm, a height H2 of about 1-4 cm, and an inner diameter ID2 that matches the outer diameter of the inlet opening 508 of the die body 502.

[0167] 37A and 37B, in one embodiment, a tubular adapter 580 is preferably assembled with the inlet opening 508 of the die body 502. The die body includes an annular groove 520 ( FIG. 33A ) surrounding the inlet opening 508 that is adapted to seat a distal sealing surface 595 at the distal end of the cylindrical wall 582 of the tubular adapter 580. FIGS. 37A and 37B show the tubular adapter 580 after it has been seated in the annular groove 520 of the die body 502. The hollow space 584 of the tubular adapter 580 is preferably aligned with the inlet opening 508 of the die body 502.

[0168] In one embodiment, with the tubular adapter 580 assembled with the inlet opening 508 at the proximal end 512 of the die body 502 of the polymer extrusion die assembly 500, a filtration element 585, such as a filtration screen, may be inserted into a cylindrical hollow space 584 surrounded by the cylindrical wall 582 of the tubular adapter 580. In one embodiment, the filtration element 585 preferably has an outer diameter that substantially matches the inner diameter of the cylindrical wall 582 such that the filtration element 585 completely covers the wetted region 553 of the inlet opening 508, as well as the contoured inlet zone 563 ( FIG. 35 ) and flow channel 586 of the die body 502.

[0169] In one embodiment, the tubular adapter 580 may be attached to or fabricated as an integral part of the die body 502. One or more filtration elements 585 may be inserted inside the tubular adapter 580, which may be directly supported by ridges 575 (FIG. 35) that lie in a common plane 552 (FIG. 34E). Additional mixing elements, such as stainless steel balls, may also be positioned inside the tubular adapter 580. In one embodiment, the proximal and distal surfaces 585, 595 of the tubular wall 582 of the tubular adapter 580 may function as sealing surfaces when the tubular adapter is installed in a polymer passage line.

[0170] 38 , in one embodiment, a polymer extrusion die assembly 600 includes a die body 602 preferably having an inlet opening 608 at a proximal end 612 of the die body and a conical opening 626 located at a distal end 616 of the die body. The die body 602 preferably includes flow channels 686 extending between a contoured inlet zone 663 and a restricted flow region 635. In one embodiment, at least some of the flow channels 686 may be angled toward a central axis A3 of the die body 602. The angle of inclination of the flow channels 686 may vary between approximately 15 and 50 degrees relative to the central axis A3 of the die body such that a distal end 697 of each flow channel 686 is positioned within a converging region 632 proximal to the restricted flow region 635.

[0171] In one embodiment, the polymer melt streams forced into the inlet openings 608 flow through the flow channels 686, over the contoured inlet zone 663, and exit the distal end 697 of each flow channel 686, then coalesce and self-mix within the converging region 632 of the die body 602. The convergent polymer melt streams then pass through a restricted flow region 635, preferably located above the apex 660 of the cone 658 of the spinneret die 606. The convergent self-mixing polymer melt streams preferably split into thin layers and are forced into the flow channels 685 while exchanging heat with the die body 602 before reaching the capillary holes 676 of the spinneret 606.

[0172] Referring to FIG. 39A, in one embodiment, a method of manufacturing a spinneret preferably includes using a vertical mill three-axis CNC machine with a spinneret blank 705. Referring to FIG. 39B, in one embodiment, the spinneret blank 705 is set in a fixture within a multi-axis CNC machine 715, where the CNC machine is programmed with G-code. The spinneret blank 705 is desirably pre-machined to the desired shape, complete with holes and perforations. In one embodiment, a three-dimensional (3D) part model in Mastercam X / 2019 / 2020 CAD software is oriented on the XY plane with a cone shape facing vertically along the Z axis. The top of the cone preferably defines the XYZ zero position. Toolpath instructions are sent to the CNC machine 715 using a roughing program using an appropriately sized carbide four-flute ball-nose end mill. The toolpath instructions preferably include a shallow Z-axis depth of cut (0.0040 inches) moving clockwise about the XYZ axes, being careful not to push the tool into the Z-axis more than set by the program. A final program can then be initiated to remove any secondary material left along the edge faces of the profile from the rough toolpath, to make finish cuts to complete the 3D profile to the final finished dimensions defined within the Mastercam CAD software. The result is the completed spinneret 706, as shown in FIG. 39C.

[0173] While the above description is directed to embodiments of the present invention, other and further embodiments of the present invention may be made without departing from the basic scope of the invention, which is limited only by the appended claims. For example, it is intended that the present invention may incorporate any feature shown in any embodiment described herein or incorporated by reference herein with any feature shown in any embodiment described herein or incorporated by reference herein and still fall within the scope of the present invention. For example, the systems, assemblies, devices, and methods disclosed herein may be used for both polymer melt and polymer solution spinning.

[0174] [Embodiment] (1) A spinneret for extruding fibers, a plate having a proximal surface and a distal surface; a plurality of holes formed in the plate extending between the proximal and distal surfaces of the plate, the holes being spaced apart from one another and each having a distal end extending along a central axis; a plurality of contoured inlet zones formed in the proximal surface of the plate, each contoured inlet zone associated with one of the holes; A spinneret wherein each contoured entrance zone extends distally from the proximal surface of the plate to the proximal end of the associated hole, and wherein the contoured entrance zones are substantially free of planar or flat surfaces perpendicular to the central axis of the distal end of the associated hole. (2) The spinneret of claim 1, wherein each hole formed in the plate has a proximal end closer to the proximal surface of the plate and a distal end closer to the distal surface of the plate. (3) The spinneret of claim 2, wherein each contoured inlet zone surrounds the proximal end of its associated hole, and the contoured inlet zone includes a contoured surface extending from the proximal surface of the plate to the proximal end of the hole. (4) The spinneret of claim 3, wherein the contoured inlet zone surrounding each hole defines a wetting region of the proximal surface of the plate immediately adjacent the contoured inlet zone surrounding each adjacent hole, and the wetting region does not have a planar or flat surface perpendicular to the central axis of the respective hole. 5. The spinneret of claim 4, wherein the contoured entrance zone comprises a contoured surface consisting of an inclined surface, a curved surface, a concave curved surface, and a convex curved surface.

[0175] (6) The spinneret of claim 1, wherein the plate has an outer diameter of about 25 to 150 mm. (7) The spinneret of claim 1, wherein the holes formed in the plate include 4 to 80 holes. 8. The spinneret of claim 1, wherein the holes are arranged in one or more concentric rings. (9) The spinneret of embodiment 8, wherein the one or more concentric rings each have an outer diameter of about 20 to 90 mm. (10) The spinneret of claim 1, wherein the distance between any two of the adjacent holes is about 3 to 17 mm.

[0176] (11) The spinneret of claim 1, further comprising a centrally located conical protrusion extending above the proximal surface of the plate. (12) The spinneret of claim 11, wherein the conical projections have bases with an outer diameter of at least 10 mm, and the conical projections have a height of about 10 to 40 mm. 13. The spinneret of claim 11, wherein the holes are located adjacent the bases of the conical projections. 14. The spinneret of claim 13, wherein the holes are arranged in an annular configuration around the base of the conical projection. 15. The spinneret of claim 1, further comprising one or more rings formed on the proximal surface of the plate, the contoured entrance zone and the holes being disposed within the one or more rings.

[0177] (16) The one or more rings are an inner ring formed in the proximal surface of the plate, the inner ring including a plurality of inner holes; an outer ring formed on the proximal surface of the plate, the outer ring including a plurality of outer holes, the outer ring surrounding the inner ring; a capillary hole formed in an underside of the plate that communicates with the distal ends of each of the inner and outer holes. 17. The spinneret of claim 16, wherein the inner ring and the outer ring are concentric. 18. The spinneret of claim 17, wherein the inner and outer rings and the contoured inlet holes are contoured such that there is no surface between adjacent ones of the holes that is parallel to the proximal surface of the plate. (19) A polymer extrusion die assembly for extruding suture fibers, comprising: a die body having a conical hollow center; a spinneret assembled with the die body, a plate having a proximal surface and a distal surface; a centrally located conical projection extending above the proximal surface of the plate; a plurality of spaced apart holes formed in the plate and extending between the proximal and distal surfaces of the plate and around a base of the conical projection, each hole having a proximal end and a distal end extending along a central axis; a spinneret comprising a plurality of contoured entrance zones formed in the proximal surface of the plate, each contoured entrance zone associated with one of the holes, each contoured entrance zone extending distally from the proximal surface of the plate to the proximal end of its associated hole, each contoured entrance zone having substantially no planar or flat surface perpendicular to the central axis of the distal end of its associated hole. (20) The polymer extrusion die assembly of claim 19, wherein each hole has a proximal end closer to the proximal surface of the plate and a distal end closer to the distal surface of the plate, and wherein each of the contoured inlet zones surrounding one of the holes is immediately adjacent to another of the contoured inlet zones surrounding an adjacent one of the holes such that no planar or flat surface remains between the adjacent holes in the proximal surface of the plate.

[0178] (21) A breaker plate for extruding fibers, a plate having a proximal surface and a distal surface; a plurality of holes formed in the plate extending between the proximal and distal surfaces of the plate, the holes being spaced apart from one another and each having a distal end extending along a central axis; a plurality of contoured inlet zones formed in the proximal surface of the plate, each contoured inlet zone associated with one of the holes; a breaker plate, wherein each contoured entry zone extends distally from the proximal surface of the plate to a proximal end of the associated hole, and wherein each contoured entry zone is substantially free of planar or flat surfaces perpendicular to the central axis of the associated hole. (22) further comprising a plurality of contoured exit zones formed in the distal surface of the plate, each contoured exit zone associated with one of the holes; 22. A breaker plate as described in embodiment 21, wherein each contoured exit zone extends distally from the distal end of its associated hole to the distal surface of the plate, and wherein the contoured exit zone has substantially no planar or flat surface perpendicular to the central axis of its associated hole. (23) The breaker plate of claim 21, wherein each hole formed in the plate has a proximal end closer to the proximal surface of the plate and a distal end closer to the distal surface of the plate. (24) The breaker plate of claim 23, wherein each contoured entry zone surrounds the proximal end of the associated hole, and the contoured entry zone includes a contoured surface extending from the proximal surface of the plate to the proximal end of the hole. (25) The breaker plate of claim 24, wherein the contoured inlet zone surrounding each hole defines a wetting region of the proximal surface of the plate immediately adjacent to the contoured inlet zone surrounding each adjacent hole, and the wetting region does not have a planar or flat surface perpendicular to the central axis of the respective hole.

[0179] 26. The breaker plate of claim 25, wherein the contoured entry zone comprises a contoured surface selected from the group consisting of an inclined surface, a curved surface, a concave curved surface, and a convex curved surface. (27) The breaker plate of claim 22, wherein each contoured exit zone surrounds the distal end of the associated hole, and the contoured exit zone includes a contoured surface extending from the distal surface of the plate to the distal end of the hole. (28) The breaker plate of embodiment 27, wherein the contoured exit zone surrounding each hole defines a wetting region of the distal surface of the plate immediately adjacent to the contoured exit zone surrounding each adjacent hole, and the wetting region does not have a planar or flat surface perpendicular to the central axis of the respective hole. (29) The breaker plate of claim 28, wherein the contoured exit zone comprises a contoured surface selected from the group consisting of an inclined surface, a curved surface, a concave curved surface, and a convex curved surface. (30) The breaker plate of claim 21, wherein the holes formed in the plate include 3 to 60 holes.

[0180] (31) Further comprising a tubular wall directly connected to the proximal surface of the plate; 22. The breaker plate of claim 21, wherein the tubular wall defines a cylindrical hollow space adapted to receive polymer mixing and / or filtering elements, such as sand, stainless steel balls, sintered mesh screens, etc., to homogenize the polymer melt and / or filter impurities from the polymer melt. (32) The breaker plate of embodiment 21, wherein the breaker plate is configured to be installed anywhere within a melt flow path from a polymer source, such as an extruder or metering pump block outlet, to an inlet of a fiber extrusion die body or die assembly. (33) A die body for extruding fibers, comprising: an inlet opening at a proximal end of the die body having a plurality of contoured inlet zones having substantially no flat surfaces perpendicular to a central axis of the die body; a conical hollow space distal to the die body; a plurality of flow channels for polymer flow through the contoured inlet zone to an outlet region at the top of the die body or near a tip region of the conical hollow space. 34. The die body of claim 33, wherein the flow channels comprise about 3 to 60 flow channels. 35. The die body of claim 33, wherein the flow channels extend along respective axes that are parallel to the central axis of the die body.

[0181] 36. The die body of claim 33, wherein the flow channels are inclined at an angle of about 15 to 50 degrees relative to the central axis of the die body such that all of the outlets of the flow channels are above or near the apex region of the conical hollow space. 37. The die body of claim 33, wherein the contoured entrance zone comprises a contoured surface selected from the group consisting of an inclined surface, a curved surface, a concave curved surface, and a convex curved surface. (38) A polymer extrusion die assembly for extruding suture fibers, comprising: a conical die having a conical center; a die body having an upper portion including a plurality of flow distribution channels, a lower portion including a conical hollow center, and a contoured inlet zone communicating with proximal ends of the flow distribution channels, the contoured inlet zone having substantially no flat surfaces perpendicular to a central axis of the die body; a tubular adapter attached to the inlet opening of the die body. (39) The polymer extrusion die assembly of embodiment 38, wherein the tubular adapter is attachable to the proximal end of the die body. (40) The polymer extrusion die assembly of embodiment 39, wherein the tubular adapter is integrally formed with the die body.

[0182] (41) The polymer extrusion die assembly of claim 38, wherein the tubular adapter includes an attachable filter holder breaker plate.

Claims

1. 1. A spinneret for extruding fibers, comprising: a plate having a proximal surface and a distal surface; a centrally located conical projection extending above the proximal surface of the plate; a plurality of holes formed in the plate extending from the distal surface of the plate toward the proximal surface of the plate, the holes being spaced apart from one another, each hole having a central axis, a proximal end, and a distal end; a plurality of contoured inlet zones formed in the proximal surface of the plate, each contoured inlet zone associated with one of the plurality of holes; the conical projection has a base, and the plurality of holes are disposed adjacent to the base of the conical projection; each contoured entrance zone surrounding the proximal end of each associated hole; each contoured entry zone includes a contoured surface extending from the proximal surface of the plate to the proximal end of each hole; the contoured surface has substantially no planes perpendicular to the central axis of each hole; The spinneret, wherein the contoured surface is comprised of an inclined surface, a curved surface, a concave curved surface, and a convex curved surface.

2. A spinneret as described in claim 1, wherein each contoured inlet zone is directly adjacent to an adjacent contoured inlet zone, and the adjacent contoured inlet zones are connected to each other by surfaces comprising inclined surfaces, curved surfaces, concave curved surfaces, and convex curved surfaces.

3. A spinneret as described in claim 1, wherein each contoured inlet zone defines a wetting region on the proximal surface of the plate immediately adjacent to an adjacent contoured inlet zone, and wherein the wetting region does not have a plane perpendicular to the central axis of each hole.

4. 10. The spinneret of claim 1, wherein the plates have an outer diameter of 25 to 150 mm.

5. 10. The spinneret of claim 1, wherein the plurality of holes formed in the plate comprises 4 to 80 holes.

6. 10. The spinneret of claim 1, wherein the plurality of holes are arranged in one or more concentric rings.

7. 7. The spinneret of claim 6, wherein the one or more concentric rings each have an outer diameter of 20 to 90 mm.

8. A spinneret as described in claim 1, wherein the distance between the central axes of adjacent holes is 3 to 17 mm.

9. 10. The spinneret of claim 1, wherein the base has an outer diameter of at least 10 mm and the conical projections have a height of 10 to 40 mm.

10. 10. The spinneret of claim 1, wherein the plurality of holes are arranged in an annular configuration around the base of the conical projection.

11. 10. The spinneret of claim 1, further comprising one or more rings formed on the proximal surface of the plate, the plurality of contoured entrance zones and the plurality of holes being disposed within the one or more rings.

12. The one or more rings are an inner ring formed in the proximal surface of the plate, the inner ring including a plurality of inner holes; an outer ring formed on the proximal surface of the plate, the outer ring including a plurality of outer holes, the outer ring surrounding the inner ring; 12. The spinneret of claim 11, including a plurality of capillary holes formed in an underside of the plate that communicate with the distal ends of each of the plurality of inner holes and the plurality of outer holes.

13. 13. The spinneret of claim 12, wherein the inner ring and the outer ring are concentric.

14. 14. The spinneret of claim 13, wherein the inner and outer rings and the plurality of contoured entrance zones are contoured such that no surface is parallel to the proximal surface of the plate.

15. 1. A polymer extrusion die assembly for extruding suture fibers, comprising: a die body having a conical hollow center; a spinneret assembled with the die body, a plate having a proximal surface and a distal surface; a centrally located conical projection extending above the proximal surface of the plate; a plurality of spaced apart holes formed in the plate extending from the distal surface to the proximal surface of the plate and extending around a base of the conical projection, each hole having a central axis, a proximal end, and a distal end; a plurality of contoured inlet zones formed in the proximal surface of the plate; each contoured entrance zone is associated with one of the plurality of spaced apart holes, each contoured entrance zone surrounding the proximal end of its associated hole; each contoured entry zone includes a contoured surface extending from the proximal surface of the plate to the proximal end of each hole; the contoured surface has substantially no planes perpendicular to the central axis of each hole; The contoured surface is comprised of an inclined surface, a curved surface, a concave curved surface, and a convex curved surface. A polymer extrusion die assembly comprising: a spinneret comprising a plurality of contoured entrance zones;

16. A polymer extrusion die assembly as described in claim 15, wherein each contoured inlet zone is directly adjacent to an adjacent contoured inlet zone, and the adjacent contoured inlet zones are connected by surfaces comprising inclined surfaces, curved surfaces, concave curved surfaces, and convex curved surfaces.

Images