JP5757470B2 - Yarn manufacturing method and yarn manufacturing apparatus - Google Patents

Description

  The present invention relates to a yarn manufacturing method and a manufacturing apparatus, and more particularly, to a yarn manufacturing method and a manufacturing apparatus for manufacturing a yarn by discharging a molten resin.

  Melt spinning is known in which a molten resin is discharged from a nozzle to produce a yarn. Yarns produced by such a melt spinning method are used for various applications, but in many applications, the diameters of the produced yarns are required to be uniform.

  For example, a polyolefin porous hollow fiber membrane produced by drawing a hollow fiber melt-spun using a crystalline polyolefin as a synthetic resin is excellent in chemical stability, strength characteristics, flexibility, etc. For this reason, it is used in a wide range of fields such as wastewater treatment, ultrapure water production, and air purification.

  The production of such a polyolefin porous hollow fiber membrane includes a spinning process in which a raw resin is melt-spun to obtain a hollow fiber, and a stretching process in which the hollow fiber obtained in the spinning process is stretched to make it porous. ing.

At this time, if the dimensions such as the diameter and thickness of the hollow fiber obtained in the spinning process are constant, troubles in the stretching process, for example, product defects due to large fluctuations in diameter after stretching, or drastically more slack than other threads Yarn appears and entangles with the adjacent yarn where extremely slack yarn runs side by side, and process troubles such as yarn breakage and winding around a roll hardly occur.
Furthermore, if the crystal structure obtained in the spinning process is homogeneous, a homogeneous porous hollow fiber membrane can be stably obtained in the stretching process, and the liquid and gas filtration performance is stabilized.

In order to obtain a hollow fiber having a uniform size and a uniform crystal structure, it is necessary to control the extrusion amount, take-up speed, and cooling behavior of the molten resin to be constant.
In order to control the amount of molten resin to be constant, a metering pump such as a gear pump is usually used, and as a highly accurate dimensional fluctuation suppression means, the fluctuation in the discharge pressure of the gear pump is detected and this fluctuation in the discharge pressure is detected. A method of feedback-controlling the gear pump rotational angular velocity based on the above is known (see Patent Document 1).

  Also, a method is known in which a planetary gear pump is used to combine a plurality of molten resin flows having different discharge amount fluctuation cycles so that the discharge amount fluctuation cycles are offset to obtain a constant extrusion amount (see Patent Document 2). .

  On the other hand, in the manufacturing process of a hollow fiber membrane, in order to increase productivity, a multi-bore batch spinning method in which a plurality of hollow fibers are spun together is often employed. In this method, molten resin supplied in a fixed amount from a gear pump is caused to flow into a plurality of branched flow paths, discharged from discharge ports provided in the respective flow paths, and a plurality of hollow fibers are simultaneously spun.

  In this method, if the cross-sectional area, shape, length, inner surface quality, temperature, etc. are different between the flow paths after branching, a difference occurs in the amount of molten resin supplied to each discharge port. There may be a difference in dimensions and crystal structure between a plurality of hollow fibers spun simultaneously.

  In such multi-spindle-type melt spinning, in order to suppress the difference in the outer diameter of a plurality of filaments that are spun at the same time, a weir-like flow control mechanism that is independent of the flow path to each outlet after branching And a method of performing feedback control that reflects the outside diameter value of the spun filamentous body in the weir opening (Patent Document 3), and an independent temperature control mechanism in each flow path, and the outside diameter of the spun filamentous body There has been proposed a method (Patent Document 4) for performing feedback control in which a value is reflected in the flow path temperature.

JP-A-9-268982 JP-A-5-11127 JP 2001-303354 A JP 2002-69739 A

  The techniques of Patent Documents 1 and 2 are techniques for suppressing a significant discharge amount fluctuation resulting from meshing of gear teeth and operating a gear pump at a low speed, and suppressing fluctuations in the outer diameter in the longitudinal direction of one filamentous body. This is a useful technique. However, in the multi-spindle batch spinning method, there is no effect of suppressing the difference in the outer diameter of the filamentous material (spot between the spindles) between the plurality of discharge ports.

  Furthermore, the techniques of Patent Documents 3 and 4 are useful techniques for suppressing the difference in the outer diameter of a plurality of filaments that are spun simultaneously, but a mechanism for controlling the flow rate and temperature separately from the molten resin supply mechanism. Further, there is a problem that the yarn manufacturing apparatus becomes complicated because feedback control based on the measured outer diameter of the filamentous body is necessary.

  Further, when the yarn is hollow, the discharge amount fluctuation causes the outer diameter or the wall thickness to fluctuate. Therefore, the techniques of Patent Documents 3 and 4 which are controls based on the outer diameter of the yarn improve the quality of the hollow fiber. It has the problem that it is difficult to make it constant.

  The present invention has been made to solve such a problem, and it is possible to simultaneously obtain a plurality of yarns having no outer diameter difference with a simple mechanism while being a multi-spindle batch spinning method with good productivity. An object of the present invention is to provide a method and an apparatus for producing a yarn that can be produced.

According to the present invention,
A method for producing a hollow fiber membrane in which a molten resin is discharged from a plurality of discharge ports to simultaneously produce a plurality of yarns,
Supplying the molten resin via a gear pump provided one by one upstream of each of the plurality of discharge ports and independently driven by a dedicated motor ;
Discharging the molten resin from each discharge port and simultaneously spinning a plurality of yarns;
Cold drawing the yarn;
Heat drawing the yarn subsequent to the cold drawing, and
A method for producing a hollow fiber membrane is provided.

  According to such a configuration, the molten resin can be uniformly and quantitatively supplied to each discharge port with a simple mechanism, and as a result, the occurrence of a difference in outer diameter in the spun yarn is suppressed.

  According to another preferred embodiment of the present invention, the molten resin metering means is a positive displacement metering pump.

According to another aspect of the invention,
A yarn manufacturing apparatus that discharges molten resin from a plurality of discharge ports to simultaneously manufacture a plurality of yarns,
A nozzle having a plurality of discharge ports for discharging the molten resin;
A plurality of molten resin dispensing device for supplying the molten resin to each of the discharge ports, each of the molten resin dispensing device, provided one by one on each of the upstream of the plurality of discharge ports dedicated motor A molten resin quantitative supply device configured to supply a fixed amount of molten resin to a corresponding discharge port,
A take-up device for picking up each discharged matter discharged from the discharge port ,
A drawing device for drawing the yarn obtained by the yarn manufacturing device ,
The stretching apparatus includes a cold stretching apparatus and a thermal stretching apparatus disposed at a subsequent stage of the cold stretching apparatus.
An apparatus for producing a hollow fiber membrane is provided.

  According to such a configuration, the molten resin can be uniformly and quantitatively supplied to each discharge port with a simple mechanism, and as a result, the occurrence of a difference in outer diameter in the spun yarn is suppressed.

  According to another preferred aspect of the present invention, the take-up device is a take-up device that collects the discharged materials collectively.

  According to another preferred aspect of the present invention, the nozzle is a nozzle that discharges the molten resin in a hollow shape.

  According to another preferred aspect of the present invention, the molten resin metering device is a positive displacement metering pump.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and manufacturing apparatus of the thread | yarn which can obtain simultaneously the several thread | yarn without an outer diameter difference with a simple mechanism, although it is a multi-spindle lump spinning system with sufficient productivity.

It is drawing which shows roughly the structure of the manufacturing apparatus of the hollow fiber used for the manufacturing method of the hollow fiber membrane of preferable embodiment of this invention. It is drawing which shows the relationship between the gear pump and motor with respect to a spinning head in the manufacturing apparatus of the hollow fiber used for the manufacturing method of the hollow fiber membrane of preferable embodiment of this invention. It is drawing which shows schematically the structure of the manufacturing apparatus of the hollow fiber used by the comparative example with respect to the Example of this invention.

  Hereinafter, with reference to the drawings, a preferred embodiment of the yarn production method and production apparatus of the present invention will be described.

  The present embodiment comprises a spinning process for melt spinning a polyolefin resin to obtain hollow fibers, and a hollow fiber membrane production method comprising a stretching process for stretching the hollow fibers obtained in the spinning process to make them porous, and It is a manufacturing apparatus used for this manufacturing method.

  However, the present invention is not limited to such a hollow fiber production method and production apparatus, but other hollow fiber production methods and apparatuses, and solid yarns such as plastic fibers (plastic optical fibers and the like). The present invention can also be applied to the manufacturing method and apparatus.

  FIG. 1 is a drawing schematically showing a configuration of a hollow fiber production apparatus 10 used in a spinning step of a hollow fiber membrane production method according to a preferred embodiment of the present invention.

The manufacturing apparatus 10 includes a resin extruder 12 that melts and extrudes a raw material resin such as crystalline polyolefin such as polyethylene, and a spinning head 14 that discharges the molten resin. In the present embodiment, the flow path through which the molten resin flows is provided with a heating device (not shown) for maintaining the resin in a molten state.
Between the resin extruder 12 and the spinning head 14, a booster gear pump 16 that pumps the molten resin melted and kneaded by the resin extruder 12 toward the spinning head 14 and a filter 18 that filters the molten resin are disposed. Yes.

  The resin used in the method for producing the hollow fiber membrane of the present embodiment is not particularly limited as long as it is a resin that can be melt-shaped. Preferred resins include polyolefins such as polyethylene and polypropylene, polysulfone, polymethyl methacrylate, polyacrylonitrile polycarbonate, polyester, nylon, thermoplastic fluororesin, polystyrene, vinyl chloride, ABS resin, and thermoplastic polyimide. Moreover, you may use the copolymer which introduce | transduced the substituent into these resins and a part of these resins or those copolymers. Further, the same type of polymers having different molecular weights may be blended and used, or two or more different resins may be mixed and used.

  A pipe line 20 that conveys the molten resin from the resin extruder 12 branches into four resin flow paths 22 in the spinning head 14. Each resin flow path 22 communicates with each of a plurality of discharge ports 26 formed in the discharge nozzle 24.

  The hollow fiber membrane manufacturing method of the present embodiment is a method of manufacturing a hollow fiber membrane by a multi-spindle spinning method. Therefore, the hollow fiber manufacturing apparatus 10 used includes a plurality of discharge ports 26. The discharge port is configured to discharge the molten resin in a hollow shape.

Productivity improves as the number of discharge ports increases. On the other hand, considering that it is necessary to cool the hollow fibers after discharge between the plurality of hollow fiber membranes, it is not preferable that the arrangement density of the hollow fibers in the apparatus is increased, and the spinning nozzle is When the size is increased, there is a concern about a temperature difference in the spinning nozzle. Therefore, in terms of quality control of the hollow fiber, the smaller the number of discharge ports, the better.
For this reason, the number of discharge ports formed in the discharge nozzle 24 is 2 or more, preferably 4 to 16, and is 4 in this embodiment.

  The arrangement of the discharge ports 26 on the discharge nozzle 24 may be concentric arrangement, series arrangement, parallel arrangement of plural rows, staggered arrangement, or the like, but is not particularly limited. Any arrangement may be used as long as cooling of the hollow fiber after discharge and temperature gradient in the spinning nozzle can be suppressed.

  Each of the four resin flow paths 22 communicating with each of the four discharge ports 26 is provided with a molten resin quantitative supply means 28 so that the molten resin can be quantitatively supplied to the discharge ports 26 for each resin flow path 22. It is configured.

The molten resin quantitative supply means 28 is required to have a function of delivering a high-temperature and high-viscosity molten resin with high quantitativeness. Devices suitable for such applications include positive displacement metering pumps such as gear pumps, diaphragm pumps, uniaxial eccentric screw pumps, plunger pumps, screw pumps, and the like.
In the present embodiment, a gear pump 28 having various advantages such as small pulsation, small size and light weight and a simple sealing mechanism is adopted as the molten resin quantitative supply means 28.

  Furthermore, the manufacturing apparatus 10 of the present embodiment may be configured to drive the four gear pumps 28 with a single motor, but a dedicated motor M is connected to each of the four gear pumps 28, and each of the gear pumps 28. However, it is preferable that the motor is driven by a motor (drive device) M provided for each gear pump.

In the present embodiment, one gear pump (molten resin quantitative supply means) 28 that is independently driven by a dedicated motor is disposed upstream of each discharge port 26. As shown in FIG. 2, the gear pumps 28 are fixed to the spinning head 14, and each gear pump 28 is connected to a dedicated motor M and a shaft S. With such a configuration, the rotation of the motor M rotating at a constant speed is transmitted to the gear pump 28 via the shaft S, and the gear pump 28 is rotated at a constant speed, whereby the molten resin is quantified with high accuracy to each discharge port 26. It becomes possible to supply.
Note that the rotation of each motor M can be individually controlled. Therefore, the discharge amount from each gear pump 28 can also be individually controlled.

  It is necessary to select a drive source for the molten resin quantitative supply means such as a gear pump that has a constant output and excellent controllability. Therefore, as the motor M, an AC servo motor or a stepping motor is most preferable because it can precisely control the rotation angle of the output shaft. Furthermore, when more accurate outer diameter management is required, the technique described in Patent Document 1 for suppressing unevenness in outer diameter may be used in combination.

  At the subsequent stage (downstream side) of the discharge port 26, a hollow fiber take-up device (not shown) that takes up the four hollow fibers 30 discharged from the four discharge ports 26, as in the conventional hollow fiber membrane manufacturing apparatus. Is provided.

  As the take-up method, a method using a Nelson roll or a godet roll, which is excellent in controllability of the take-up speed and can be conveyed by friction without being held so as not to crush the hollow fiber, is adopted. The roll size, the number, etc. are appropriately set according to the spinning speed and the number of spindles.

  In the manufacturing apparatus 10 of the present embodiment, a hollow fiber take-up device that individually takes up four hollow fibers may be used. However, since only one compact device needs to be used, four hollow fibers are used. A hollow fiber take-up device that pulls up at a constant speed is more preferable.

  A drawing device for drawing the hollow fiber 30 to make it porous is provided at the rear stage (downstream side) of the hollow fiber take-up device. This stretching device includes an upstream cold stretching device and a downstream (downstream) thermal stretching device, and has a configuration similar to that of a prior art stretching device.

  The hollow fiber taken up by the take-up device may be introduced into the drawing device as it is, but once wound up around the bobbin at the subsequent stage (downstream side) of the take-up device, a plurality of bobbins are hung at once, and the hollow fiber is combined with the yarn. After that, it is preferable to introduce it into a stretching apparatus because production efficiency is improved.

  In such a hollow fiber manufacturing apparatus 10, each of the plurality of discharge ports 26 is melted via a gear pump (molten resin quantitative supply means) 28 provided corresponding to each discharge port and driven by a dedicated motor. Resin is supplied, then molten resin is discharged from each discharge port 26, and four hollow fibers 30 are spun simultaneously.

  The hollow fiber manufactured by the hollow fiber manufacturing apparatus 10 is an unstretched hollow fiber highly oriented in the fiber axis direction, and has an inner diameter of about 100 to 2000 μm and a wall thickness of about 15 to 800 μm. This unstretched hollow fiber is heat-treated under a temperature condition of 100 to 130 ° C., more preferably 115 to 130 ° C., and subjected to a stretching treatment. The necessary heat treatment (annealing) time is 30 minutes or more. By this annealing treatment, the crystal structure becomes more complete, and the elastic recovery rate at 50% elongation is 50% or more.

  Stretching in the manufacturing method of the present embodiment includes cold stretching and subsequent thermal stretching. In cold drawing, it is preferable to fix the drawing point in order to destroy the crystal structure and generate microcraze uniformly.

  According to the method for producing a hollow fiber membrane having such a configuration, even in a highly productive multi-spindle spinning method, there is no unevenness in the discharge amount between the discharge ports, and there is no unevenness in the size and crystal structure. Quality hollow fiber can be manufactured.

  In addition, when a porous hollow fiber membrane is produced by stretching such hollow fibers, it is possible to obtain a porous hollow fiber membrane that is less prone to process troubles such as yarn breakage and roll wrapping at the time of stretching, and has stable filtration performance. it can.

  Without being limited to the above-described embodiment of the present invention, various changes and modifications can be made within the scope of the technical idea described in the claims.

The present invention will be specifically described by the following examples.
Example 1
The same hollow fiber spinning apparatus as that shown in FIG. 1 was used. The product names and product numbers of each device are as follows.
・ Extruder: Tanabe Plastics Machine, single screw molten resin extruder VS30-40
・ Spinning gear pump: Kawasaki Heavy Industries, Ltd. Gear pump KH1-1.2-36H 4 units (in series at 100mm interval on spinning head)
・ Spinning gear pump drive motor: Oriental Motor stepping motors AR66AS-H100 4 units (connected to the gear pump spindle)
・ Spinning nozzle: annular nozzle made by chemical fiber nozzle (special order)
・ Discharge port: Outer diameter 21.5mm / Inner diameter 14.8mm 4 pieces (equal distribution every 90 ° on 50mm pitch circle diameter)
-Filter: Nihon Seisen made leaf disk filter NF2M-08D 6 sheets-Filter case: Inside diameter 83mm x Depth 55mm Made of SUS316

In this embodiment, a booster gear pump is used for the purpose of assisting the pressure loss of the filter.
-Booster gear pump: Kawasaki Heavy Industries, Ltd. Gear pump KH1-3-38H 1 unit (arranged in the filter case)
-Booster gear pump drive motor: Oriental Motor stepping motor AR98AS-H100 1 unit (connected to the booster gear pump main shaft)

  Hollow fiber melt spinning was performed using Novatec HD's HY540 grade, which is a high-density polyethylene made from Japan Polyethylene as a raw material resin.

  The spinning temperature was 160 ° C. for the raw material supply section of the extruder, and 165 ° C. for all the screw sections and thereafter. The rotation speed of the main shaft was 23.36 rpm for the booster gear pump and 14.6 rpm for the spinning gear pump. The roll peripheral speed of the winding device was 70 m / min.

  Under the above conditions, after spinning and winding four hollow fibers, each hollow fiber was unwound for 30 minutes at a linear velocity of 50 m / min to measure the mass of each hollow fiber. The fiber was wound and separated to measure the mass of each hollow fiber. As a result, as shown in Table 1, the maximum-minimum difference in mass spots between the four spindles was 0.5 g.

(Example 2)
In the same apparatus as in Example 1, spinning was performed under the same conditions except that the spinning temperature after the screw part of the extruder was 175 ° C., and the mass of each hollow fiber after splitting was measured. As a result, as shown in Table 1, the maximum-minimum difference in mass spots between the four spindles was 0.7 g.

Example 3
The hollow fiber spun in Example 1 was wound around a bobbin and drawn by the following procedure to obtain a porous hollow fiber membrane.
The hollow fiber was wound around a bobbin and heat treated at a constant length at 115 ° C. for 16 hours. Subsequently, after 288 hollow fibers were collectively bundled and cold-drawn 180% at a deformation rate of 0.03 m / sec at room temperature, the total draw amount was 315% in a heating box heated to 112.5 ° C. (ie The porous hollow fiber membrane was continuously produced by stretching in the roller so that the deformation speed was 0.128 m / sec until the total draw ratio was 6.0).
The deformation speed means a value obtained by dividing the drawing amount (m) in the drawing section by the time (seconds) for the yarn to pass through the drawing section.

  As a result of visual observation of the hollow fiber bundle being manufactured, all 288 were evenly stretched, and no yarn slacking excessively from other yarns appeared, and process troubles such as yarn breakage and roll winding did not occur.

Example 4
The hollow fiber spun in Example 2 was wound around a bobbin and drawn in the same procedure as in Example 3 to obtain a porous hollow fiber membrane.

  As a result of visual observation of the hollow fiber bundle being manufactured, all 288 were evenly stretched, and no yarn slacking excessively from other yarns appeared, and process troubles such as yarn breakage and roll winding did not occur.

(Comparative Example 1)
The hollow fiber spinning apparatus shown in FIG. 3 was used.
The biggest difference in configuration with the hollow fiber spinning device used in Examples 1 and 2 is that there is one spinning gear pump 32 and the resin flow path is branched into four on the exit side of the spinning gear pump. is there. The branched resin flow paths were manufactured so that the inner diameter, length, and tube wall quality were as equal as possible between the resin flow paths. The product names and product numbers of each device are as follows.
・ Extruder: Mitsubishi Heavy Industries, Ltd. single screw molten resin extruder Barrel inner diameter φ45mm, L / D25
・ Spinning gear pump: 1 gear pump KH1-1.752-2-02 manufactured by Kawasaki Heavy Industries ・ Spinning gear pump drive motor: 2HMGA 6: 1 manufactured by Mitsubishi Heavy Industries (connected to the gear pump main shaft)
-Filter: Nippon Seisen φ86mm disk filter (# 325) 1 sheet

The spinning nozzle used was the same as that in Examples 1 and 2, such as the discharge port diameter, the number of nozzles, and the arrangement.
Using the same raw material resin as in Examples 1 and 2, hollow fiber melt spinning was carried out.

The spinning temperature was 168 ° C. with an extruder and 167 ° C. after the exit of the extruder.
The main shaft rotation speed of the spinning gear pump was 40 rpm.
The roll peripheral speed of the winding device was 70 m / min.

  Under the above conditions, after spinning and winding four hollow fibers, each hollow fiber was unwound for 30 minutes at a linear velocity of 50 m / min to measure the mass of each hollow fiber. The fiber was wound and separated to measure the mass of each hollow fiber. As a result, as shown in Table 1, the mass spot between the four spindles had a maximum-minimum difference of 9.7 g.

(Table 1) Unit: g

(Comparative Example 2)
The hollow fiber spun in Comparative Example 1 was wound around a bobbin and drawn in the same procedure as in Examples 3 and 4 to obtain a porous hollow fiber membrane.

  When the hollow fiber bundle being manufactured was visually observed, yarns that were drastically more slack than other yarns appeared at some places between the rollers, entangled with neighboring yarns that run along with the slack yarns, and rolled from there Winding occurred, and then the thread was broken, resulting in a process trouble.

DESCRIPTION OF SYMBOLS 10: Hollow fiber manufacturing apparatus 12: Resin extruder 14: Spinning head 16: Booster gear pump 18: Filter 20: Pipe line 22: Resin flow path 24: Discharge nozzle 26: Discharge port 28: Gear pump (molten resin fixed quantity supply means)
30: Hollow fiber
M: Motor

Claims (6)

A method for producing a hollow fiber membrane in which a molten resin is discharged from a plurality of discharge ports to simultaneously produce a plurality of yarns,
Supplying the molten resin via a gear pump provided one by one upstream of each of the plurality of discharge ports and independently driven by a dedicated motor ;
Discharging the molten resin from each discharge port and simultaneously spinning a plurality of yarns;
Cold drawing the yarn;
Heat drawing the yarn subsequent to the cold drawing, and
A method for producing a hollow fiber membrane characterized by the above. The molten resin metering means is a positive displacement metering pump;
The method for producing a hollow fiber membrane according to claim 1 . A yarn manufacturing apparatus that discharges molten resin from a plurality of discharge ports to simultaneously manufacture a plurality of yarns,
A nozzle having a plurality of discharge ports for discharging the molten resin;
A plurality of molten resin dispensing device for supplying the molten resin to each of the discharge ports, each of the molten resin dispensing device, provided one by one on each of the upstream of the plurality of discharge ports dedicated motor A molten resin quantitative supply device configured to supply a fixed amount of molten resin to a corresponding discharge port,
A take-up device for picking up each discharged matter discharged from the discharge port ,
A drawing device for drawing the yarn obtained by the yarn manufacturing device ,
The stretching apparatus includes a cold stretching apparatus and a thermal stretching apparatus disposed at a subsequent stage of the cold stretching apparatus.
An apparatus for producing a hollow fiber membrane. The take-up device is a take-up device that collects the discharged materials at once.
The apparatus for producing a hollow fiber membrane according to claim 3 . The nozzle is a nozzle that discharges the molten resin in a hollow shape.
The manufacturing apparatus of the hollow fiber membrane of Claim 4 . The molten resin metering device is a positive displacement metering pump;
The apparatus for producing a hollow fiber membrane according to any one of claims 3 to 5 .

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