JPH03294509A - Filament spinneret assembly and spinning method by said assembly - Google Patents

Abstract

PURPOSE: To obtain a sheath/core fiber having uniform cross section shape by controlling a flow rate of a sheath polymer flowing from a sheath polymer flow passage of a distributor plate to a core polymer flow passage with a shim separating a spinnerette from the distributor plate. CONSTITUTION: This spinneret assembly has a shim 11 positioned between a distributor plate 10 and a spinnerette 12 is fixed to the distributor plate with a bolt 19 and a round hole 21 of the shim is suitably engaged with a core polymer flowing passage 22. A flowing rate of the sheath polymer flowing from a sheath polymer flowing passage 17 to the flowing passage 22 can be controlled in corresponding to changes of a concentration of the sheath polymer and density of the polymer.

Description

[Detailed description of the invention]

[00013

[Industrial Application Field] The present invention relates to a method and apparatus for spinning composite filaments,
and improved products produced by the method. Additionally, the present invention relates to a method and apparatus for spinning improved composite filaments into concentric or eccentric sheath/core relationships. [0002] BACKGROUND OF THE INVENTION Composite filaments in the form of sheath/core are well known and
A variety of spindle packs and spinnerets have been used to produce such systems. Conventional spinning assemblies feed sheath-forming material perpendicularly to the orifice of a spinneret and inject the core-forming material into the sheath-forming material as the core-forming material flows into the spinning orifice. Contains stages. [0003] A composite spinning assembly is disclosed in U.S. Pat. No. 4,406,850, in which a molten sheath polymer is deposited on the upper surface of a spinneret positioned between rows of elevated spinneret core inlets. is injected in a ribbon flow into the concave slot-like portion of. U.S. Pat. No. 4,251,200 also includes spaced apart spinneret plates and a distribution plate, the distribution plates having mutually opposed holes in each orifice formed in the spinneret; A composite filament spinning assembly is disclosed having a hole and a pedestal extending about a common axis to the extrusion orifice. Additionally, the assembly includes an orifice plate that prevents access to the orifice. [0004] The concentricity of the core and sheath capillaries in the prior art spinning assemblies described above, and in other spinning assemblies, is not satisfactory. It is difficult to properly position the prior art distribution plate and spinneret, properly align the distribution plate and the flow path, achieve the proper pressure drop, and produce a sheath/core composite fiber of uniform cross-section. there were. [0005] Typical of the cited and illustrated prior art spinning apparatus is that the air gap between the outlet face of the distribution plate and the inlet face of the spinneret is constant. Therefore, if the concentration of the sheath polymer changes or the core-sheath ratio changes, control of the pressure drop is not possible in prior art assemblies. As explained below, it is necessary to control the pressure drop of the polymer near the spinneret to obtain uniform composite fibers in each filament. [0006] Additionally, in these spinning assemblies where the annular gap between the distribution plate and the spinneret is constant, the pressure of the polymer is high enough to occasionally bend the spinneret away from the distribution plate to open the gap; Vary the pressure drop. The distribution plate and spinneret outlet and inlet passages closest to the center and source of sheath polymer have the widest voids, and the outlet and inlet passageways furthest from the center have the narrowest width voids. The sheath polymer flows preferentially into the inner passageway, degrading the uniformity of the composite filament. [0007]

[Means to solve the problem]

The present invention provides an improved method and apparatus for producing an improved composite sheath/core filament of uniform cross-section, which allows the cap pack assembly to be adjusted to the concentration of the sheath polymer and the density of the polymer. The sheath polymer flow rate into each spinneret core polymer flow path can be easily adjusted and controlled separately. [0008]

【Example】

Referring to the accompanying drawings, and in particular to FIG. 1, a composite filament spin pack assembly may be comprised of a distribution plate 10, a shim 11, and a spinneret 12. The distribution plate 10 has a flow path 1
It is positioned to receive a melt extruded sheath polymer or sheath polymer solution through channel 3 and a melt extruded core polymer or core polymer solution through channel 14 . Each of the sheath and core polymers are guided into respective flow channels 13.14 by conventional melt extrusion pumps and filter means, not shown. [0009] Distribution plate 10 serves to form the core polymer into filaments and to guide the flow of sheath polymer to spinneret 12. The core polymer is delivered to the uniform underside of the distribution plate 10 through a number of channels 16. Channels 16 can be arranged in any number of rows or columns depending on their dimensions, the concentration of the core polymer, the length of the channels 16, and the flow characteristics of the particular core polymer. Each channel 1
The bottom of 6 is tapered to provide the desired diameter of the core filament. The density of the channels 16 of the distribution plate 10 is not limited, but for example, the core polymer is molten polyethylene terephthalate and the outlet diameter of the channels is in the range of 0.1 mm to 1.0 mm. In this case, each flow channel can be based such that an area of 10 mm 2 of the spinneret can be utilized. [0010] Sheath polymer flowing through channel 13 is delivered to channel 17 and through channel 17 to spinneret 12. By way of non-limiting example, the channel 17 is positioned axially within the distribution plate 10 such that once the sheath polymer exits the channel 17;
Desirably, the flow toward the inlet of the channel 22 is radially outwardly flowing. [0011] The shim 11 is disposed between the distribution plate 10 and the spinneret 12 and is secured to the distribution plate 10 and the spinneret 12 by bolts 19 that engage threaded recesses 20 in the distribution plate 10. maintained in a certain relationship. Distribution plate 10 and spinneret 12 are positioned relative to each other by dowel pins 18. To prevent bending and separation of the distributor plate 10 and spinneret 12 that can occur when operating conventional spinneret pack assemblies, bolts 19 are arranged annularly in the center of the assembly as shown in FIG. ing. The shim can be made of a variety of materials, such as stainless steel or brass, with stainless steel being preferred. The shim can also be formed as a single piece or as two separate inner and outer parts. The number and location of bolts 19 are such that distortion can be prevented, preferably limited to 0.002 mm or less. [0012] The shim 11 preferably has a thickness variation of 0.002 mm.
The circular hole 21 has a certain wall thickness that is less than or equal to the thickness of the distribution plate 1.
6, and proper alignment with the spinneret flow path 22. Usually between 0.025 and 0, as explained below.
．． Shims 11 with different wall thicknesses in the range of 0.050 mm are utilized to adjust for changes in sheath polymer concentration, changes in polymer density, or changes in pressure drop. [0013] The smooth, uniform upper surface of spinneret 12 is concave to provide each channel 22 with a channel 23 for flow of sheath polymer. The circular raised portion, that is, the button 26 is connected to the flow path 22.
It surrounds. The raised portion or button 24 extends upwardly from the channel 23 to a height equal to the top surface 25 of the spinneret 12. The amount of sheath polymer flowing outwardly through channel 23 and past button 24 to channel 22 depends on the degree of pressure drop due to the thick canister of shim 11. This pressure drop is inversely proportional to three times the height dimension of the air gap 26 between the distribution plate 1o and the spinneret 12. Tight control of the height of this gap can be achieved by shims 11 and maintained by the inner circle of bolts 19. The depth of the depression in channel 23 is selected so that a small pressure drop (typically 20-50 psi) can be achieved in the radial direction relative to the top surface of the spinneret. The wall thickness of the shim is selected to provide a pressure drop across the raised button 24, typically on the order of 100 to 1000 psi. [0014] As is apparent from the drawings, each channel 22 must be concentrically aligned with its corresponding channel 16. The core polymer flows through channel 16 and channel 22;
It exits the spinneret as a composite fiber core. The sheath polymer flows through channels 17, 23 and voids 26 to form a sheath around the filaments of core polymer to form the composite fiber described above. The center axis of the flow passages 16 in the distribution plate is within a circle of radius less than 200 microns, preferably 50 microns, from the center axis of the spinneret counterbore. [0015] A method of manufacturing concentric composite fibers is further illustrated in FIG. Shim 11 allows sheath polymer 31 to pass through channel 23, over button 23, and through gap 26 to form channel 2.
2 and positioned to form a concentric sheath around core polymer 30 as shown. [0016] A method of manufacturing an eccentric sheath/core fiber is illustrated in FIG. The holes in shim 11 are positioned to restrict the flow of sheath polymer 33 in the manner shown. The eccentric cross-section of the formed composite filament is also illustrated in FIG. 4 [0017] FIG. 5 illustrates a spinneret assembly for producing a sheath/core composite fiber in which the core has a non-circular cross-section. ing. As shown, the core polymer flows through channels 16 in the distribution plate to a core profile shim 36 that includes channels 17 having a figure 7-shaped cross section. The core polymer flows through core profile shim 36 to channel 22 in the manner described above. The sheath polymer is delivered to channel 22 in the manner described above to produce a composite fiber having sheath 39 and core 38. [0018] Composite sheath produced by the spinneret assembly of the present invention/
The core filament is each JP-A-3-294509 (g
') The filament has a uniform cross section. The core and sheath of each filament have an open cross-sectional shape and cross-sectional area. The rate of variation in the diameter of the composite fiber of the present invention is
Preferably, it is no more than 2.5%, based on diameter measurements of at least 25 filaments produced at the same time. The rate of variation (CV) is determined by the following formula. [0019] Cv=standard deviation of filament diameter/average diameter of filament xlo. It is desirable that the fluctuation rate of the eccentricity of the 25 concentric composite filaments according to the present invention manufactured at the same time be 1.0% or less. The rate of variation (ECV) of eccentricity is obtained from the following equation. [0020] ECV=displacement amount of core center/composite filament diameter x10
Typically, the diameter variation of commercially produced sheath/core composite filaments is 4.5% or more, and the eccentricity variation of concentric sheath/core composite filaments is 60% or more. [0021] The invention will now be described with respect to the production of sheath/core composite filaments, where the sheath polymer comprises a molten polyethylene blend and the core polymer comprises molten polyethylene terephthalate, as described below.
Those skilled in the art will appreciate that other core polymers can be employed. [0022] High concentration polyethylene coated with maleic anhydride is made by the method of US Pat. No. 4,684,576, the disclosure of which is incorporated herein by reference. This high concentration polyethylene resin is 25g710 at 1900C.
min [ASTMD-1238(E)J melt pour point (M
FV) and before extrusion (ASTM D 79
2) The concentration was 0.955 g/cc. After extrusion, the (7) MFV is measured to be 15 g/10 min. This product is mixed with a linear low concentration polyethylene resin having a MFV of 18 g/10 min at 190°C, and the maleic anhydride content of the mixture is between 0.09 and 0.12.
% by weight. Thereafter, on the next side, the polymer mixture used as the 1900
It has a MFV of 16g710min in C and its concentration is 0.9
It was 32g/cc. The next core polymer was polyethylene terephthalate with an inherent density (ASTM D2857) of 0.645. [0023] Experimental Example 1 Using the spinneret assembly shown in FIG. 1 with a spinneret hole diameter of 0.374 mm, core-sheath ratios were 60:40 (run 1), 70:30 (run 2), and 80:20. (Driving 3
) wt% spun into concentric composite sheath/core filaments. The spun molten sheath polymer was flowed into channel 17 at a temperature of 27,500°C. The molten core polymer is 2
It was made to flow through the channel 16 at a temperature of 750C. The spinneret jackpot production was 0.852, 0.903 and 0.935 g/min, respectively. [0024] The composite filament was quenched in air at 300C, and
It was wound at a speed of 800 fpm. The resulting filament was drawn at a temperature of 600C with a drawing ratio of 3.0 and crimped in a conventional stuffer box. After drawing and heat curing at a temperature of 900C, the filament
．． Fiber lengths of 5 inches were cut and the properties were as listed in Table 1 below. [0025] Table 1 Times Tensile Elongation Stress Crimp Tenacity Strength per crimp process %
10% 7 inch %Denier D-2101-82ASTM-D-ASTM-D-AS
TM-D-ASTM-D-ASTM-D-ASTM-D
-2101-822101-822102-82D-3
937-822101-823937-8213,14
4,15411,114,026,626,523,7
93,68540,811,427,028,533,
953, 60650, 813, 928, 825, 5-5
2 = Solution spun composite filaments can be produced using the spinneret assembly of the present invention. By adjusting the dimensions of the cap pack and the concentration of the polymer solution,
For example, composite filaments can be made from cellulose acetate and viscose. [0026] Although the principles, preferred embodiments, and mode of operation of the present invention have been described, these disclosures are merely examples of the present invention and are not intended to be limiting, and the scope of the present invention for which protection is sought is limited. It is not limited to such specific disclosures. Those skilled in the art will be able to devise variations and modifications without departing from the spirit of the invention.

[Brief explanation of the drawing]

[Figure 1] FIG. 2 is a perspective view of a base pack assembly of the present invention.

FIG. 2 is a longitudinal cross-sectional view of a multiple channel distribution plate/shim/spinneret assembly.

FIG. 3 is a longitudinal cross-sectional view of a distribution plate/shim/spinneret assembly for producing concentric composite filaments.

FIG. 4 is a longitudinal cross-sectional view of a distribution plate/shim/spinneret assembly for producing eccentric composite filaments.

[Figure 5] Distribution plate/shim/ for manufacturing composite filament with non-circular cross section
FIG. 2 is a longitudinal cross-sectional view of the spinneret assembly.

[Explanation of symbols]

10 Distribution plate 11 Sim 12 Spinneret 13 Flow path flow path flow path flow path dowel pin bolt recess hole flow path flow path button top surface button core polymer polymer sheath polymer contour shim core sheath

[Document core]

drawing

[Figure 1]

[Figure 2]

[Figure 3]

[Figure 4]

[Figure 5] 158-

Claims (18)

[Claims] 1. A spinneret having a distribution plate having a plurality of spaced apart core polymer channels and a number of sheath polymer channels; and a spinneret having a plurality of spaced apart core polymer channels and a number of sheath polymer channels. , a spinneret with each core polymer flow channel axially aligned with a flow channel outlet of a respective core distribution plate; and a core that supplies pressurized polymer to the core polymer flow channel inlet of each of the distribution plates. a filament spinneret assembly for producing a composite filament of a sheath/core composite filament, comprising a polymer supply means and a sheath polymer supply means for supplying pressurized sheath polymer to an inlet of a polymer flow path of said sheath; a flow of sheath polymer positioned between a spinneret and the distribution plate to space the spinneret from the distribution plate and from an outlet of the sheath polymer flow path in the distribution plate to each spinneret core polymer flow path; A filament spinneret assembly comprising shim means for separately controlling the filament spinneret assembly. 2. The spinneret pack of claim 1, wherein the upper surface of the spinneret containing the inlets of the spaced apart core polymer channels also comprises:
A spinneret comprising a sheath polymer flow path, said shim means being positioned to provide a controlled pressure drop between each said flow path and an adjacent spinneret flow path inlet. pack. 3. The spindle pack of claim 2, wherein said sheath polymer is flowed radially outward through said flow path to a core polymer flow path inlet of each spinneret. Base pack. 4. The cap pack of claim 3 wherein said shim means are positioned to form a concentric sheath/core composite fiber. 5. The cap pack of claim 3 wherein said shim means is positioned to form an eccentric sheath/core composite fiber. 6. The cap pack of claim 3, wherein said shim means comprises an upper shim and a lower shim, the upper shim adjacent said distribution plate being axially adjacent to said plurality of spaced apart distribution plate core polymer channels. a plurality of spaced apart core polymer channels spaced apart in alignment in a direction, each spaced apart shim core polymer channel having a cross section that is different from a cross section of each core polymer channel of the distribution plate; Features a cap pack. 7. A method of melt spinning a sheath/core composite fiber in which multiple flows of the core polymer melted under pressure are axially aligned from flow channels of a distribution plate to flow channels of the multiple distribution plates, respectively. flowing the pressurized molten sheath polymer through channels disposed on the upper surface of the spinneret to surround the channel inlet of the spinneret. and introducing the sheath polymer from the flow path into each flow path of the spinneret and into each flow of core polymer at a controlled pressure drop. 8. The method of claim 7, wherein said sheath polymer is flowed radially outward through said channels to an inlet of each core channel of said spinneret. . 9. The method of claim 8, wherein each of the composite fibers exiting the spinneret is a concentric sheath/core filament. 10. The method of claim 8, wherein each composite fiber exiting the spinneret is an eccentric sheath/core filament. 11. A composite sheath/core melt spinnable polymer filament produced by the method of claim 7. 12. The composite sheath/core polymer filament of claim 11, wherein said sheath polymer is a polyolefin and said core polymer is a polyester. 13. The composite filament according to claim 11,
A composite filament, wherein the polyolefin is maleic anhydride-coated high-density polyethylene and linear low-density polyethylene, and the core polymer is polyethylene terephthalate. 14. Multiple simultaneously manufactured composite sheath/core polymer filaments having uniform cross-sections. 15. The filament according to claim 14, wherein the filament has a diameter variation rate of 2.50% or less. 16. The filament according to claim 15, wherein each filament is a concentric sheath/core filament and has a variation rate of eccentricity of 1.00% or less. 17. The multifilament of claim 16, wherein said sheath polymer is a polyolefin and said core polymer is a polyester. 18. The multifilament of claim 16, wherein the sheath polymer is maleic anhydride coated high concentration polyethylene and linear low concentration polyethylene, and the core polymer is polyethylene terephthalate. Features numerous filaments.