JP4001819B2 - Spinneret assembly for forming hollow fibers - Google Patents

Abstract

The invention provides a spinnerette assembly (300) for forming single component and multicomponent hollow fibers of the sheath/core type. The spinnerette assembly contains an extrusion orifice (355) and a core forming material passage (350) in communication with the extrusion orifice (355). A hollow needle (330) extends through the extrusion orifice in a concentric manner to define an annular passage (353) surrounding the needle (330). The core forming material passage (350) includes a core forming material inlet port (351) extending from a surface of the spinnerette assembly to an anterior of the assembly and a transverse passage (352) extending from the core forming material port to the annular passage surrounding the needle. A bore forming fluid passage (312; 314) communicates with the interior of the needle. The spinnerette assembly for multicomponent hollow fibers contains at least one sheath forming material passage also in communication with the extrusion orifice.

Description

[0001]
The present invention relates to a spinnerette assembly that forms a hollow fiber. The invention particularly relates to an improved spinneret for more efficient and accurate products of multi-component hollow fibers.
[0002]
For various applications, it is well known to use one or more various hollow fibers typically made of polymeric materials. For example, hollow fibers are membranes for filling materials for pillows, as separation materials for blankets and clothing, and for applications for gas separation, hemodialysis, water purification, and other filters. ) As a carpet. For thin film applications, the hollow fiber is a single component or multiple components (as a hollow structure core with a sheath provided around the core acting as a separate layer). multiple of component). The fibers can be bundled together and provided in a tubular housing to provide a separation device known as a permeator. Typically, hollow fibers have a diameter on the order of 30 to 1000 microns and are relatively thin. Therefore, the apparatus and method for producing the hollow fiber must be very accurate in order to be able to control the fiber diameter and the concentricity of the core and sheath around the bore. Don't be.
[0003]
Many spinneret assemblies have been embodied for the production of sheath / core type single component hollow fibers and multi-component hollow fibers. In particular, devices have been developed to ensure a uniform supply of fiber forming fluid to the spinneret orifice with the purpose of producing hollow fibers of uniform diameter, composition and concentricity. These spinnerets use a means for supplying a fluid placed in a spinning orifice to form a hollow fiber hole. Typically, a tube or needle is used for that purpose, and a gaseous or liquid bore fluid is ejected from the tube so that the fiber core is removed from the spinning orifice around the hole fluid. Occupies the hole space to be extruded. For melt spinning, the nascent fibers are solidified by cooling with a gaseous or liquid cooling fluid. For solution spinning, the initial fiber is solidified by evaporation of the solvent or by contacting the fiber with a solvent extraction solution, resulting in condensation of the polymer solution to form the fiber wall.
[0004]
A typical spinneret assembly for a multi-component fiber as described in U.S. Pat. No. 6,057,056 includes a front plate and a back plate that are spaced apart but face each other to provide a liquid channel therebetween. I have. The front plate is provided with an extrusion orifice passing therethrough, and at least one plate facing the other plate has a platen type indentation to clamp the liquid channel in the area surrounding the extrusion orifice inlet. Is provided. In this way, the flow of the sheath forming material is concentrated substantially in the radial direction toward the orifice inlet. A tube is placed at the orifice inlet to supply hole fluid. However, an ongoing problem is the uniform supply of core forming material and sheath forming material during the formation of multi-component fibers. The best spinneret of this type is made one at a time, mostly by hand. As a result, parts made for one spinneret are not always compatible with other spinnerets. If the parts are not replaceable, some damage to one part of the spinneret assembly tends to render the entire assembly unusable. In conventional assembly or cleaning of a bicomponent or hollow fiber spinneret, the fluid injection tube or needle is very easily bent slightly so that it is off-center of the spinning orifice. If this happens, the spinneret cannot be used until it is repaired.
[0005]
Another problem associated with conventional spinnerets relates to producing concentricity between the hole and the fiber wall of the single component hollow fiber, as well as between the core and the sheath of the multi component hollow fiber. Conventional spinnerets tend to form hollow fibers where the hole / fiber wall and the core / sheath are not concentric. The concentricity of the sheath and the core is important for obtaining a uniform fiber. The concentricity of the sheath and core is typically obtained by adjusting the metering surface to regulate (meter) the polymer flow. A metering surface is created by machining two surfaces in close proximity to create a narrow opening, which weighs the polymer being extruded at a uniform pressure and rate. U.S. Patent No. 6,057,031 discloses a sheath by metering around a polymer sheath to be extruded around a polymer core, such as with the generation of an annular wedge-shaped flow of sheath polymer around an axially contained fluid flow. Disclosed are methods for maintaining the concentricity of the core.
[0006]
In order to maintain the concentricity of the fiber wall around the hole, a number of other spinnerets have been provided that center the hole in the tube and spinneret plate. For example, U.S. Patent No. 6,057,059 describes a modular spinneret assembly that is engaged with a plurality of screws screwed through a spinneret plate for centering a tube and an orifice of a spinneret. These adjustment screws are unreliable and tend to move the tube out of concentric adjustment when the spinneret is disassembled, cleaned and reassembled. There are many devices that ensure a uniform supply of homogeneous sheath-forming fluid to the orifices of a multi-orifice spinneret to produce multiple hollow fibers with concentric layers, uniform denier, and other properties. Has been proposed. Such devices typically include a change in orifice diameter or arrangement, and single or multiple spinneret plates. The lack of concentricity and uniformity leaves problems in the manufacture of such single and multiple components.
[0007]
Another problem with current spinnerets is the ability to uniformly supply polymer fluid around the tube or needle within the spinneret. U.S. Patent No. 6,057,031 describes a spinneret having a plurality of individual material passages formed around a needle to supply a polymer stream around the needle. The polymer streams from these individual passages can be united and melted together to form a single annular flow around the tube or needle as the polymer stream traverses the main polymer flow passage. There must be. If complete coalescence is not achieved, a seam will occur below the length of the fiber at the boundary where the individual streams have not fully assembled. Therefore, it is desirable to have a spinneret structure that can produce concentric and uniform fibers without the risk of seams.
[0008]
The present invention is to provide an improved spinneret for the production of hollow fibers suitable to overcome the limitations of conventional spinnerets. The new spinneret assembly consistently produces uniformly sized single and multi-component hollow fibers whose fiber walls are concentric with the holes for a high degree of precision. Therefore it becomes possible. By doing so, these spinneret assemblies further reduce hollow fiber imperfections, increase hollow fiber manufacturing run time, reduce spinneret maintenance time, and spinneret assembly. Make it easy. The present invention is particularly well suited for producing high quality multi-component fibers having one or more sheath layers in an efficient manner.
[0009]
To achieve these objectives, a first aspect of the present invention is a spinneret assembly for forming hollow fibers comprising:
Comprising at least one extrusion orifice formed in the spinneret assembly;
A hollow needle extending through each extrusion orifice, which extends in a concentric manner to define an annular passage around the needle of the extrusion orifice;
Comprising at least one core-forming material passage formed in the spinneret assembly;
Each core-forming material passage comprises a core-forming material inlet port extending from the surface of the assembly into the assembly and at least one transverse passage extending from the core-forming material port to each annular passage. A spinneret assembly.
[0010]
The novel spinneret assembly is suitable for providing a composite hollow fiber defined by a tubular inner core fiber wall surrounded radially outwardly by a tubular sheath layer. The adaptability requires the spinneret assembly just described to be added with a first sheath forming material passage with a first sheath forming material port on the surface of the spinneret assembly. A first sheath-forming material passage extends into each tubular passage.
[0011]
Another aspect of the invention is a method for forming hollow fibers comprising:
Supplying a core forming material to each annular passage of the spinneret assembly, wherein the core forming material enters the spinneret assembly through one or more core forming material inlet ports, and the assembly Through a portion of the transverse passage that completely surrounds each needle in a continuous manner and through an annular passage communicating with the extrusion orifice;
Extruding a core-forming material through the extrusion orifice and around each needle;
Injecting a hole forming fluid into each needle to provide a fiber with a hole forming fluid disposed in the center of the core forming material to exit the spinneret assembly through an extrusion orifice. ;
Solidifying the hollow fiber by cooling, solvent evaporation, or solvent extraction;
Prior to solidification of the hollow fibers, optionally comprising passing the initial extruded hollow fibers through an air gap;
It is a method.
[Patent Document 1]
United Kingdom (UK) Patent No. 830,441
[Patent Document 2]
U.S. Pat. No. 3,458,615
[Patent Document 3]
U.S. Pat. No. 4,493,629
[Patent Document 4]
U.S. Pat. No. 5,320,512.
[0012]
The invention will now be described by way of a preferred embodiment and the accompanying drawings.
The invention particularly relates to the production of hollow fibers for various applications, such as thin film separation applications, and in particular gas separation. In its basic shape, the hollow fibers are open at the ends and are cylindrical tubes whose walls have a homogeneous composition. Such a shape of the hollow fiber is referred to as a “single component” fiber. The central opening that defines the hollow portion of the fiber is sometimes referred to as the “core”. “Multi-component” hollow fibers can also be made. The term “multiple components” means that the wall of the hollow fiber tube is formed with a composition layer. The innermost layer adjacent to the core is referred to herein as the “core” portion of the fiber. The outer layer surrounding the core layer of multi-component fibers is referred to as the “sheath” section. The convention is employed to identify the radially outer layer adjacent to the core as the “first sheath” layer or portion. Subsequent outer layers are designated as “second sheath” layers or portions, “third sheath” layers or portions, and the like. For unity of terminology, the single component hollow fiber wall is referred to herein as the fiber core, although the single component does not have a sheath portion.
[0013]
In a first preferred embodiment of the present invention for the extrusion of a plurality of single component hollow fibers as shown in FIGS. 1A and 2A, the spinneret assembly 100 comprises a spinneret body 110, a bottom plate 120. , And a needle 130. The detailed arrangement shown in FIG. 1A is for co-extrusion of 12 hollow fibers, but the spinneret assembly 100 produces a single filament or any number of multiple fibers as required. Can be embodied to. The base end portion of each needle 130 is attached to each needle installation hole 111 formed in the spinneret main body 110 by a drill or other mechanical processing. The outer shape of the proximal end portion of the needle 130 and the diameter of the needle installation hole 111 are preferably set so that the proximal end portion of the needle 130 is attached in order to attach the needle 130 to the spinneret body 110 in a leak-free manner. The dimension is such that it can be pressed into the needle installation hole 111. Needle 130 can be attached to spinneret body 110 in any other suitable manner that allows hole access at the proximal end of needle 130 to hole-forming fluid passage 112 of spinneret body 110. . The bottom plate 120 is attached to the spinneret body 110 by bolts screwed into the through holes 132 or similar fixtures 131. An expanding recess 156 is formed in the bottom plate 120 to allow a number of extruded fibers to exit the spinneret assembly 100 without interference. In the preferred embodiment, the multiple extrusion arrangements are arranged in a linear or circular form.
[0014]
The hole forming fluid passage 112 is formed in the spinneret main body 110 and extends through the spinneret main body 110 to each needle installation hole 111 so as to communicate with a passage formed through the needle 130. . Each hole forming fluid passage 112 includes a hole forming fluid inlet port 113 on the surface of the spinneret body 110. This structure allows a hole-forming flow that is directed into the extruded fiber in order to maintain the hollow structure of the extruded fiber in the manner described below.
[0015]
A core-forming material passage 150 is formed in the spinneret body 110 and a core-forming material, such as a polymer material passing therethrough, is delivered to the extrusion orifice 155. Each core-forming material passage 150 includes an inlet port 151 that is a hole extending in a direction substantially parallel to the needle 130. Each core-forming material passage 150 also includes a transverse passage 152 that extends from the core-forming inlet port 151 and extends to the top of an annular passage 153 that defines the top of the extrusion orifice 155. The transverse passage 152 is defined by a backcut formed in the spinneret body 110 by a tool inserted through the core forming material port 151. The transverse passage 152 is generally around the needle 130 to allow the core forming material to be evenly distributed around the needle 130 and evenly introduced into the annular passages 153 and 154. It extends.
[0016]
Another preferred embodiment of the novel spinneret assembly suitable for producing a large number of multi-component fibers can be understood by referring to FIGS. Similar parts in different figures of the drawings are given like reference numerals. Channels 144 and 145 formed on the bottom surface of the spinneret body 110 communicate with a gap 141 defined between the spinneret body 110 and the bottom plate 120. A shim 140 provided between the spinneret body 110 and the bottom plate 120 is concentric around the core forming material as the core forming material flows through each annular passage 153 and 154. Define the dimensions of the gap 141 to provide a uniform supply of sheath forming material in the method.
[0017]
The sheath forming material inlet port 142 and the sheath forming material passage 143 allow the sheath forming material to pass through the sheath forming material inlet port 142 and the sheath forming material passage 143, through the channels 144 and 145, and through the gap 141. In order to be fed through, the spinneret body 110 is formed to communicate with the channel 144. As the sheath forming material exits the gap 141, it is evenly distributed around the core forming material at the intersection of the gap 141 and the annular passage 154.
The operation of the novel spinneret assembly will now be discussed. Assume that the hollow fiber to be formed is a multi-component. In order to produce a single component hollow fiber, the sheath forming operation and apparatus in the following discussion must be ignored.
[0018]
In operation, the spinneret assembly 100 is provided to the spinning machine through the mounting hole 115 using a suitable securing mechanism such as a bolt or the like. The machine's hole forming fluid supply, core forming material supply, and sheath forming material supply are coupled to hole forming fluid inlet port 113, core forming material inlet port 151, and sheath forming material inlet port 142, respectively. ing. Note that there is one hole forming fluid inlet port 113 and one core forming material inlet port 151 for each extrusion orifice 155. One sheath forming material inlet port 142 then provides the sheath forming material distribution to each extrusion orifice through the sheath forming material passage 143, channels 144 and 145, and the gap 141. These ports can be placed in any manner and can be any number as appropriate to distribute the material to the appropriate passages. For hollow fiber spinning, the core-forming material, the sheath-forming material, and the hole-forming fluid are simultaneously distributed in the spinneret 100 at a known pressure and flow rate that pushes the hollow fiber (ie, spins). Is done. Typically, the core forming material is injected at about 300-500 psig (pounds per square inch, gauge), the sheath forming material is injected at about 150-300 psig, and the hole forming fluid is injected at about 4-5 psig. The
[0019]
The core-forming material travels through the core-forming material inlet port 151, through the core-forming material passage 150 and into the transverse passage 152 and into the upper annular passage 153. At the same time, the sheath forming material travels through the sheath forming material inlet port 142 and through the sheath forming material passage 143 into the channel 144. It should be noted that the dimensions of the channels 144 are designed to provide each channel 145 with sheath forming material at the inlet at essentially the same pressure so as to provide a uniform supply of sheath forming material through the gap 141. I must. At the outlet of the gap 141, the flow of sheath forming material intersects the core forming material in the gap between the upper annular passage 153 and the lower annular passage 154, and thus concentric around the outside of the core forming material. To form a uniform layer or sheath of sheath forming material. Further, upon delivery of the core forming material and sheath forming material through the spinneret assembly 100, the hole forming fluid is injected through the hole forming fluid passage 112 into the hole forming fluid inlet port 113 and into the needle 130. Is done. The hole forming fluid emerges from the proximal end of the needle 130 in or just downstream of the extrusion orifice 155. The core forming material and the sheath forming material pass through the lower annular passage 154, concentrically around the needle 130 to the outside of the extrusion orifice 155, and the hole forming fluid emerging therefrom is simultaneously extruded. What is extracted as is a fiber with a hole forming fluid in the center concentrically surrounded by a core forming material concentrically covered with a sheath forming material.
[0020]
As best shown in FIGS. 1 and 2, the transverse passage 152 is a back cut having an end portion that completely surrounds the needle 130 in a continuous manner, and the upper annular passage 153 Communicate. This construction eliminates the problem of uniform distribution of the core forming material around the needle 130. This also eliminates the problem of longitudinal seaming down the fiber wall due to incomplete melting of the plurality of core-forming material flows in the annular passage, as disclosed in US Pat. Similarly, when the spinneret assembly is removed from the spinning machine, the spinneret cleaning is relatively easy because the core forming material passage 150 and the transverse passage 152 are easily accessible. This facilitates cleaning and reduces the turnaround time for the spinneret. The core-forming material passage 150 can also be easily machined into the spinneret body 110 by a drill, and the transverse passage 152 is also known as electrical discharge machining (“EDM”) using angled electrodes. Is easily and precisely formed by the technique. Furthermore, since the needle 130 is securely fixed to the spinneret body in the needle installation hole 111, the concentric alignment of the needles in the upper and lower annular passages 153 and 154 is compensated, and is therefore labor intensive. Alignment processing is eliminated, thereby further reducing turnaround time.
[0021]
The preferred embodiment spinneret assembly 100 has fewer parts and is easier to manufacture than conventional spinneret. FIG. 3 shows an alternative structure to the spinneret body of the first preferred embodiment, further simplifying the spinneret manufacturing process. In the first preferred embodiment shown in FIG. 2, the hole forming fluid passage 112 is angled and highly accurate without damaging the integrity of the needle placement hole 111 having a relatively small diameter. In order to accurately meet and communicate with the needle installation hole 111, it must be machined, for example with a drill. The spinneret body of FIG. 3 has an alternative configuration that eliminates this complex machining step and therefore reduces the manufacturing cost of the spinneret. In particular, the second hole-forming fluid passage 114 is machined substantially parallel to the core-forming material passage 150, extends from the surface of the spinneret body 110 to the needle placement hole 111, and Concentric. Since the second hole forming fluid passage 114 is coaxial with the needle placement hole 111, the machining process is very simple. The hole forming fluid passage 112 ′ begins at the hole forming fluid inlet port 113 and intersects the second hole forming fluid passage 114 at a point substantially away from the needle placement hole 111 to the spinneret body 110, 50. Machined. The angled hole forming fluid passage 112 ′ has a second diameter because the diameter of the angled passage 112 ′ and the second hole forming fluid passage 114 is relatively large compared to the diameter of the needle installation hole 111. Are easily machined to communicate with a perforated fluid passage 114 (which can be machined prior to machining of the angled passage 112 '). The opening of the second hole forming fluid passage 114 at the face of the spinneret body 110 is plugged before or during installation of the spinneret assembly 100 to the spinning machine to avoid leakage of the hole forming fluid. Or sealed. Other aspects of the other configuration of FIG. 3 are similar to the configuration of FIG. 2 described above.
[0022]
A second preferred embodiment of the present invention is shown in FIG. 4 and represents a method of increasing the number of fibers per spinneret by two factors. For purposes of illustration and clarity, the numeration used in FIG. 4 is 100 greater than for the corresponding FIGS. FIG. 4 is a plan view of the spinneret main body 210. The distinguishing feature between this embodiment and the embodiment depicted in FIGS. 1, 2 and 3 is that each core-forming material passage 250 is divided into two transverse passages 252a and 252b in the shape of each backcut. It is formed. Each transverse passage 252a and 252b is provided with an annular passage 253a and 253b (corresponding to the annular passage 153 in FIGS. 2 and 3), and needles 230a and 230b (corresponding to the needle 130 in FIGS. 2 and 3). It has been. Similarly, other aspects of the spinneret body 110 and the bottom plate 120 (shown in FIGS. 1, 2 and 3) are provided as corresponding aspects of the spinneret body 210 and the bottom plate 220.
[0023]
3 and 4, transverse passages 252a and 252b extend from core-forming material passage 250 to annular passages 253a and 253b around respective needles 230a and 230b of the corresponding extrusion orifice. The plurality of needles 230a and 230b are provided in the spinneret main body 210 and communicate with the hole forming fluid passages 214a and 214b. Each needle extends through a corresponding extrusion orifice 255a and 255b defined by cylindrical upper and lower annular passages 253a and 253b and 254a and 254b, respectively. Channels 244 and 245 formed on the bottom surface of the spinneret body 210 communicate with gaps 241 a and 241 b defined between the spinneret body 210 and the bottom plate 220. A liner 240 provided between the spinneret body 210 and the bottom plate 220 is a sheath-forming material around the core-forming material in a concentric manner at each intersection of the gaps 241a and 241b and the annular passages 254a and 254b. The dimension of the gap 241 that provides a uniform supply of is defined.
[0024]
The sheath forming material inlet port 242 and the sheath forming material passage 243 allow the supplied sheath forming material to pass through the sheath forming material inlet port 242, the channels 244 and 245, and the gaps 241a and 241b. For this purpose, the spinneret body 210 is formed so as to communicate with the channel 244. The hole forming fluid is supplied to the spinneret body 210 through the hole forming fluid inlet port 213. Hole forming fluid is distributed from each hole forming fluid inlet port 213 through channels 212a 'and 212'b to each hole forming fluid passage 214a and 214b. Thus, the spinneret assembly 200 can be attached to the same spinning machine to produce twice as many fibers. One of ordinary skill in the art can foresee further examples for spinning multiple fibers (eg, 3, 4, 5), more than two, based on the above examples.
[0025]
FIG. 5 illustrates a third embodiment of the present invention, which is suitable for producing three component hollow fibers. For purposes of illustration and clarity, the calculation method used in FIG. 5 to accommodate the components of FIGS. 1, 2, and 3 is 200 greater than that of FIGS. The spinneret assembly 300 includes a spinneret body 310, a bottom plate 320, a plurality of needles 330 (one of which can be seen in FIG. 5), and an intermediate plate 360 provided between the spinneret body 310 and the bottom plate 320. It has. The liner 340 a is provided between the intermediate plate 360 and the bottom plate 320. The spinneret body 310, the intermediate plate 360, the bottom plate 320 and the liners 340a and 340b are assembled into an integral body during use, which will be described in detail below. The proximal end portion of each needle 330 is attached to each needle installation hole 311 formed in the spinneret body 310 by, for example, a drill or other machining process, for example, by a press fit. The bottom plate 320 and the intermediate plate 360 are attached to the spinneret body 310 together with a liner 340a that defines a gap 341a by a fastener 331 such as a bolt or the like screwed into the through-hole 332.
[0026]
Openings corresponding to the annular passages 353, 363, and 354 are formed in the spinneret body, the intermediate plate, and the bottom plate, respectively, through which the core forming material, the core material, and the first sheath forming material are formed. And the core forming material plus the first and second sheath forming materials protrude from each other. This nascent three component hollow fiber eventually exits the spinneret assembly through extrusion orifice 355. A flared recess 356 is formed in the bottom surface of the bottom plate 320 so that each extruded fiber is interfered for further processing by the spinning machine in which the spinneret assembly 300 is provided. Without leaving the spinneret assembly 300. The channels 344a and 345a are formed on the bottom surface of the spinneret body 310 and communicate with the gap 341a. The channels 344b and 345b are formed on the top surface of the spinneret main body 310 and communicate with the gap 341b.
[0027]
A core-forming material passage 350 is formed in the spinneret body 310, through which a core-forming material, such as a polymer material, is introduced into each extrusion orifice. Each core-forming material passage 350 includes a core-forming material inlet port 351 that is a hole extending in a direction substantially parallel to the extrusion orifice. Each core-forming material passage 350 also includes a transverse passage 352 that extends from the core-forming material inlet port 351 to the top portion of the annular passage 353 that defines the top of the extrusion orifice. A transverse passage 352 is inserted through the core-forming material passage 350 and is formed in the spinneret body 310 by a tool and also allows the core-forming material to be introduced uniformly into the annular passage 353. It is defined by a backcut that extends completely around the needle 330.
[0028]
The hole forming fluid inlet port 313 and the hole forming fluid passages 312 and 314 are formed in the spinneret main body 310 so as to open and communicate with the needle installation hole 311. This arrangement allows the hole forming fluid to be introduced into the extrusion orifice to maintain the hollow structure of the extruded fiber in the manner described below.
The first sheath forming material inlet port 342a allows a first sheath forming material, such as a polymer material, into the first sheath forming material inlet port 342a through the first sheath forming material passage 343a and into the channel 344a. 345a is formed in the spinneret body 310 to communicate with the channel 344a to allow introduction into the annular passage 363 through the gap 341a.
[0029]
Similarly, the second sheath forming material inlet port 342b allows a second sheath forming material, such as a polymer material, to pass through the second sheath forming material inlet port 343b into the second sheath forming material inlet port 342b. And is formed in the bottom plate 320 to communicate with the channel 344b to allow it to be introduced into the channels 344b and 345b through the gap 341b and into the annular passage 354. Other aspects of the third preferred embodiment are similar to those of the first preferred embodiment, and similar members are labeled with the prefix "3".
[0030]
The operation of the third preferred embodiment is similar to the first preferred embodiment. However, the second sheath forming material passes through the second sheath forming material inlet port 342b, through the second sheath forming material passage 343b, into the channels 344b and 345b, through the gap 341b, and into the annular passage 354. Run. As the second sheath forming material enters the annular passage 354, it is evenly disposed around the material flowing from the annular passage 363 (eg, core forming material coated with the first sheath forming material) into the annular passage 354. Is done. Therefore, the hollow fiber having the core, the first sheath uniformly attached to the core, and the second sheath uniformly attached to the sheath plus core are all formed by a coaxial method.
[0031]
The various ports, channels, and passages of the spinneret assembly described above may be formed in any manner, and any number is possible to form a fiber having multiple sheaths and cores. For example, the core-forming material passage may be any shape or structure and may comprise multiple channels or a single channel. The spinneret assembly can be machined using any known technique such as drilling, electronic electrical discharge machining (EDM), or any other suitable process. There can be any number of extrusion orifices. The present invention can be used to make hollow fibers of any type and material such as compliance to extrusion. Various angles and dimensions can be varied to suit a particular application. The spinneret assembly can be made of any suitable material such as steel, monel, aluminum, or alloys thereof. The core-forming material and sheath-forming material can also be of a type such as a polymer melt or solution, a ceramic paste, and the like, subject to extrusion. The hole forming fluid is, for example, an inert gas or a solution.
The invention has been described by means of preferred embodiments. However, various modifications can be made without departing from the purpose of the invention as defined in the claims.
[Brief description of the drawings]
FIG. 1A is a plan view of a spinneret according to a preferred embodiment of the present invention suitable for producing single component hollow fibers.
FIG. 1 is a plan view of a spinneret according to another preferred embodiment of the present invention suitable for producing a multi-component hollow fiber.
2A is a cross-sectional view of the embodiment taken along line AA of FIG. 1A showing one extrusion arrangement.
FIG. 2 is a cross-sectional view of the embodiment along the line AA of FIG.
FIG. 3 is a view showing another structure of the spinneret body of the first preferred embodiment suitable for manufacturing a multi-component hollow fiber.
FIG. 4 is a plan view of another preferred embodiment of the present invention for spinning a plurality of filaments from a single core forming material passage.
FIG. 5 is a cross-sectional view of another preferred embodiment of the present invention for spinning multi-sheath hollow fibers.

Claims (19)

A spinneret assembly for forming one or more composite hollow fibers comprising:
A single spinneret body;
At least one extrusion orifice formed in the single spinneret body;
A hollow needle fixed to a needle installation hole formed in the single spinneret body, the needle installation hole receiving a portion of the hollow needle and around the needle in the at least one push-out orifice To define at least one annular passage, the hollow needle extends concentrically through each at least one extrusion orifice;
A hole forming fluid passage formed in the single spinneret body, the hole forming fluid passage communicating with the interior of each of the hollow needles;
At least one core forming material passage formed in the single spinneret body, each of the at least one core forming material passage extending from a surface of the spinneret body to an interior of the single spinneret body. A core-forming material inlet port extending to the core-forming material port and at least one transverse passage extending from the core-forming material port to each of the at least one annular passage;
A sheath forming material passage formed in the single spinneret body, the sheath forming material passage comprising a material port extending from a surface of the single spinneret body to each annular passage. Spinneret assembly. The at least one transverse passage is a cut-out portion behind the at least one core-forming material passage that completely surrounds the hollow needle in a continuous manner and communicates with the at least one extrusion orifice. The spinneret assembly as described. 2. The core forming material port extends substantially parallel to the at least one extrusion orifice, and the at least one transverse passage extends substantially perpendicular to the core forming material port. Spinneret assembly. The spinneret according to claim 1, wherein the spinneret assembly includes the single spinneret body and a bottom plate, and is separated from each other by a liner disposed between the single spinneret body and the bottom plate. Base assembly. The spinneret assembly according to claim 4, wherein each needle installation hole communicates with an inlet port of the hole forming fluid at the surface of the single spinneret body through the hole forming fluid passage. The hole forming fluid passage is coaxial with the needle and communicates with the needle, and the first hole forming fluid conduit from the hole forming fluid conduit toward the surface of the single spinneret body. 6. A spinneret assembly according to claim 5, comprising a second hole forming fluid conduit extending at an angle with respect to the other hole forming fluid conduit. The spinneret assembly of claim 4, wherein the extrusion orifice extends through a portion of the single spinneret body and the bottom plate. The spinneret assembly of claim 4, wherein the core forming material passage is formed in the single spinneret body. The spinneret assembly of claim 4, wherein a gap between the single spinneret body and the bottom plate defines the sheath forming material passage. A spinneret assembly for forming one or more multi-layer sheath composite hollow fibers comprising:
A single spinneret body;
At least one extrusion orifice formed in the single spinneret body;
A hollow needle fixed to a needle installation hole formed in the single spinneret body, the needle installation hole receiving a portion of the hollow needle and around the needle in the at least one push-out orifice To define at least one annular passage, the hollow needle extends concentrically through each at least one extrusion orifice;
A hole forming fluid passage formed in the single spinneret body, wherein the hole forming fluid passage is in communication with the interior of each needle;
At least one core forming material passage formed in the single spinneret body, each of the at least one core forming material passage extending from a surface of the spinneret body to an interior of the single spinneret body. A core-forming material inlet port extending to said at least one transverse passage extending from said core-forming material port to each said at least one annular passage;
A first sheath forming material passage comprising a first sheath forming material port extending from a surface of the single spinneret body to each of the at least one annular passage; and A spinneret assembly comprising a second sheath forming material passage comprising a second sheath forming material port extending from a surface of the spinneret assembly to each of the annular passages. 11. The spinneret assembly of claim 10, wherein the transverse passage is a cut-out portion behind the core-forming material passage that completely surrounds the needle in a continuous manner and communicates with the extrusion orifice. The spinneret assembly of claim 10, wherein each core forming material port extends substantially parallel to the extrusion orifice and the transverse passage extends substantially perpendicular to the core forming material port. The spinneret assembly includes a single spinneret body, an intermediate plate, and a bottom plate, a first liner disposed between the single spinneret body and the intermediate plate, the intermediate plate, The spinneret assembly of claim 10, wherein the spinneret assembly is separated from each other by a second liner disposed between the bottom plate. 14. The spinneret assembly of claim 13, wherein each of the needle placement holes communicates with the hole forming fluid inlet port at the surface of the single spinneret body via the hole forming fluid passage. The hole forming fluid passage is coaxial with the needle and is in communication with the needle, and the first hole is formed from the hole forming fluid conduit toward the surface of the single spinneret body. The spinneret assembly of claim 14, further comprising a second hole forming fluid conduit extending at an angle with respect to the forming fluid conduit. The spinneret assembly of claim 13, wherein the extrusion orifice extends through a portion of the single spinneret body, the intermediate plate, and the bottom plate. The gap between the single spinneret body and the intermediate plate defines the first sheath forming material passage, and the gap between the intermediate plate and the bottom plate is the second sheath forming material passage. 14. The spinneret assembly of claim 13, wherein the spinneret assembly is defined. The second sheath forming material passage comprises an inlet port for the second sheath forming material located on an outer surface of the bottom plate and in communication with a channel formed in the bottom plate; The spinneret assembly of claim 17, wherein is in communication with the gap defined between the bottom plate and the intermediate plate. 11. A spinneret assembly according to claim 1 or 10, comprising a number of transverse passages and extrusion orifices for each core forming material port.

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