JP2021177003A - Solution spinning nozzle - Google Patents

Abstract

To provide a solution spinning nozzle with reduced risk of damaging a nozzle in an incidental work of assembly, decomposition, cleaning, etc., while maintaining qualities of yarns to be spun at the conventional arts, and also achieving long nozzle life and reducing application cost.SOLUTION: A solution spinning nozzle 1 is a spinning nozzle for discharging a solution and has a flat face 11 at a nozzle tip 15; on the flat face, a plurality of discharge holes 7 having a size to be included in the flat face, for discharging a solution, and a groove 8 surrounding the discharge holes are provided.SELECTED DRAWING: Figure 1

Description

The present invention relates to a solution spinneret for spinning a raw material liquid, wherein the discharge holes are multi-rowed to reduce the risk of damage to the spinneret.

In recent years, non-woven fabrics having a fiber diameter of micron order to nano order have been used in various fields such as sanitary materials such as filters, diapers and masks, medical materials, and medical applications. Melt blow method, spun bond method, and solution spinning method are generally used as techniques for producing these non-woven fabrics, and the production method is selected according to the product application.

Among the above-mentioned production methods, the solution spinning method can produce fibers made from a polymer that is decomposed and absorbed in a living body, and is expected to be used in medical applications. As a solution spinning method, Patent Document 1 discloses a method in which a solution polymer is discharged from a large number of needle-shaped nozzles, the discharged polymer is stretched by high-speed air discharged from around the nozzles, and the polymer is fiberized. ing.

On the other hand, the melt blow method is a method in which a molten polymer is discharged from a melt blow mouthpiece, and the molten polymer discharged by high-speed air ejected from around a nozzle is stretched to fiberize the polymer. As a general method of the melt blow mouthpiece used in the melt blow method, Patent Document 2 discloses a method of discharging a molten polymer from a large number of holes formed at the apex of the nozzle tip.

However, in the method disclosed in Patent Document 2, there is a risk of damaging the tip. In order to reduce this risk, Patent Document 3 discloses a method in which a large number of holes are formed on a flat surface provided at the tip of a nozzle and a molten polymer is discharged from the large number of holes. Since the tip of the base is not easily crushed in this method, the risk of accidentally damaging the base can be reduced in incidental work such as assembling, disassembling, and cleaning the base.

Japanese Patent No. 6246055 Japanese Unexamined Patent Publication No. 6-166944 Japanese Unexamined Patent Publication No. 55-90663

In the configuration of the solution spinneret disclosed in Patent Document 1, it is necessary to arrange a large number of needle-shaped nozzles in order to increase the production amount, and the discharge straightness of the solution polymer greatly depends on the nozzle mounting accuracy. Installation of each nozzle is very troublesome.

On the other hand, the melt blow caps disclosed in Patent Documents 2 and 3 discharge the molten polymer from nozzles having a large number of holes, so that the labor of installation work can be reduced. Therefore, it is being studied to divert the melt blow mouthpiece to the solution spinning method.

However, when the melt blow mouthpiece is diverted to the solution spinning method, the solvent volatilizes around the discharge hole and the polymer is precipitated, and the precipitated polymer may block the discharge hole and cause discharge clogging. In addition, in the process of discharge clogging, large particles of the solution polymer drips and drops to generate foreign matter, and the solution polymer collects in the unclogging discharge holes, so the discharge amount from the discharge holes increases, and the time As the fiber diameter increases with the passage of time, the fiber diameter of the non-woven fabric becomes uneven and the quality deteriorates. In particular, the structure of the melt blow mouthpiece disclosed in Patent Document 3 is such that when the solution polymer is diverted to the solution spinning method, the solution polymer wets and spreads along the flat surface at the tip of the nozzle, so that the solvent volatilizes and the polymer precipitates. Discharge clogging is likely to occur, and the quality of the non-woven fabric is likely to deteriorate.

The present invention provides a solution spinning mouthpiece that can reduce the risk of damage to the mouthpiece during incidental work such as assembly, disassembly, and cleaning, extend the life of the mouthpiece, and reduce operating costs, while maintaining the quality of the yarn to be spun at the same level as the conventional technology. offer.

The first solution spinning mouthpiece of the present invention that solves the above problems has a flat surface at the tip of the mouthpiece.
On the flat surface, a plurality of discharge holes for discharging a solution having a size that fits on the flat surface and a groove surrounding each discharge hole are formed.

The first solution spinneret preferably has a circular discharge hole and a concentric shape in which the groove surrounds the discharge hole.

The second solution spinning mouthpiece of the present invention that solves the above problems has a flat surface at the tip of the mouthpiece.
At the tip of the mouthpiece, a plurality of discharge holes for discharging a solution having a size protruding from the flat surface are formed.
A groove is formed between the adjacent discharge holes on the flat surface.

The second solution spinneret preferably has the discharge hole having a circular shape observed from the flat surface.
The groove is a part of a concentric circle surrounding the discharge hole.

The first solution spinneret and the second solution spinneret preferably have a shape in which the edge of the discharge hole and the edge of the groove are in contact with each other.

According to the solution spinning mouthpiece having a large number of holes of the present invention, by providing a groove on the flat surface at the tip of the mouthpiece, the solution polymer discharged from the discharge hole is prevented from spreading wet along the flat surface, and as a result, the solvent It is possible to prevent the discharge holes from being clogged with the polymer that has volatilized and precipitated. Further, since the structure does not have a large number of needle-shaped nozzles arranged side by side, the risk of damaging the base in incidental work such as assembly, disassembly, and cleaning can be reduced, the life of the base can be extended, and the operating cost can be reduced.

It is a schematic diagram which shows the structural cross section of the 1st solution spinning mouthpiece of this invention. It is a schematic diagram which shows the arrow A of FIG. It is sectional drawing of the base along the C1-C1 line and the C2-C2 line of FIG. It is a schematic diagram which shows another embodiment of the 1st solution spinning mouthpiece of this invention, and is the figure corresponding to FIG. 2 and FIG. 3a). It is a schematic diagram which shows the embodiment of the 2nd solution spinner | spinneret of this invention, and is the figure corresponding to FIG. It is a schematic diagram which shows another embodiment of the 2nd solution spinning mouthpiece, and is the figure which corresponds to FIG. 2 and FIG. 3a). It is a schematic diagram which shows the process of discharging a solution polymer in the embodiment of FIGS. 2, 4 and 5. 2 is a schematic view showing a process in which a solution polymer is stretched by high-speed air in the embodiments of FIGS. 2 and 5.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited thereto.

[First solution spinneret]
First, an example of the first embodiment of the solution spinneret of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing a structural cross section of the first solution spinneret. The first solution spinneret is composed of a nozzle plate 2 for discharging the solution polymer, a base plate 3 for supplying blow air for stretching the solution polymer, and an air nozzle 12 for rectifying the blow air. Hereinafter, each component will be described in detail.

The nozzle plate 2 has a polymer introduction path 10 for introducing a solution polymer supplied from the slit 6 of the base plate 3, and communicates with a plurality of discharge holes 7. The hole diameter D of the nozzle hole 7 is determined in consideration of the polymer viscosity and the pressure loss due to the hole length L. However, in order to prevent the occurrence of defects due to minute polymer lumps called shots, the hole diameter D is reduced in diameter and per hole. It is preferable to reduce the amount of the polymer discharged from the above because the polymer is easily stretched. Further, when the pore diameter D is reduced, the flow rate of blow air required to obtain the desired spinning diameter is small, and the blow air can be efficiently blown to the polymer. Therefore, the pore diameter D is preferably 100 μm to 400 μm. The tip 15 of the nozzle plate 2 has a flat surface 11, the flat surface 11 has a discharge hole 7, and a groove 8 surrounding each discharge hole is formed.

The base plate 3 has a polymer supply port 9 for receiving the solution polymer at the upper part, and inside the base plate 3, a manifold 5 for widening the solution polymer supplied from the polymer supply port 9 in the Y direction and a rectifying polymer. It has a slit 6 to be polymerized. The manifold 5 and the slit 6 are shaped so that the polymer can flow uniformly according to the viscosity of the solution polymer and the flow rate of the polymer. The manifold 5 is not limited to a circular shape as long as it has a shape that uniformly widens the inflowing polymer. The slit 6 communicates with the polymer introduction path 10 of the nozzle plate 2 connected to the base plate 3.

The solution polymer flowing in from the polymer supply port 9 flows through the polymer supply port 9, the manifold 5, the slit 6, and the polymer introduction path 10 and is discharged from the discharge hole 7, and is stretched by the high-speed air ejected from the air nozzle 12. , Opened and becomes fibrous.

The air nozzle 12 adjusts the air velocity in the gap between the air lip plate 4 and the nozzle tip 15 of the nozzle plate 2.

The base plate 3 is provided with a blow air supply port 13 that communicates with the air nozzle 12. Two blow air supply ports 13 are provided on the base plate 3 in order to uniformly apply blow air from both sides of the nozzle tip 15 of the nozzle plate 2 to the solution polymer discharged from the nozzle hole 7. Further, it is preferable that the supplied blow air is uniformly dispersed in a large number of blow rectifying holes 14 and communicates with the air nozzle 12.

Next, the forms of the flat surface 11, the discharge hole 7, and the groove 8 of the nozzle plate 2 will be described with reference to FIGS. 2 to 4.
FIG. 2 is a schematic view showing arrow A in FIG. Whether the discharge hole 7 protrudes or fits into the nozzle flat surface 11 is determined by the magnitude relationship between the width W of the flat surface and the hole diameter D in the X direction of FIG. In the first solution spinneret, the hole diameter D is smaller than the width W of the flat surface, and the discharge hole 7 fits in the nozzle flat surface 11. The discharge hole 7 is arranged between the two grooves 8a in the X direction and between the two grooves 8b in the Y direction, and surrounds the discharge hole 7 at the intersection ABCD of the groove 8a and the groove 8b. As long as the number of grooves 8 surrounds the entire circumference of the discharge hole 7, a plurality of grooves 8 may be formed. The groove 8a is formed between the edge of the discharge hole 7 and the edge of the flat surface 11, and the groove length W8a in the X direction is (width W / 2-hole diameter D / 2 of the flat surface) or less. ing. The groove 8b is formed between the edges of the adjacent discharge holes 7, and the groove length W8b in the Y direction is equal to or less than (the sum of the adjacent discharge hole intervals P-the radius of the adjacent discharge holes). ..

3a) is a schematic view showing a cross section of the base along the line C1-C1 of FIG. 2, and FIG. 3b) is a schematic view showing a cross section of the base along the line C2-C2 of FIG. The larger the depth 8c of the groove 8a and the depth 8d of the groove 8b, the more difficult it is for the solution polymer to adhere along the nozzle plane, so that the wetting spread can be suppressed, which is preferable. However, if the depths 8c and 8d are too large, the thickness of the wall partitioning the grooves 8a and 8b from the polymer introduction path 10 becomes thin, and a hole penetrating the polymer introduction path 10 may be formed. 8c and 8d are smaller than the hole length L and are determined in consideration of the withstand voltage of the nozzle. Further, the larger the angles θ and φ formed by the grooves 8a and 8b and the flat nozzle portion 11 shown in FIGS. 3a) b), the better the liquid drainage. Therefore, 30 ° or more and 90 ° or less are preferable, and 45 ° or more and 90 ° or less. Is more preferable. The angles θ and φ at both ends of the groove 8 are preferably the same angle in order to suppress the spread of wetting from the discharge holes on both sides. In FIGS. 3a) and 3b), the groove 8a and the groove 8b have an inverted U-shaped cross section, and the cross section is tapered toward the bottom of the groove 8, but the cross-sectional shape of the groove is limited to this. No. The cross-sectional shapes of the grooves 8a and 8b may be the same or different.

FIG. 4 is a schematic view showing another embodiment of the first solution spinneret, and is a diagram corresponding to FIGS. 2 and 3a). In the embodiment of FIG. 4a), the discharge hole 7 is circular, and the groove 8 is formed so as to surround the discharge hole 7 and be concentric with the discharge hole 7. Since the groove 8 approaches the entire circumference of the discharge hole 7, the range in which the discharged solution polymer wets and spreads on the flat surface of the nozzle can be narrowed. FIG. 4b) is a schematic view showing a cross section of the base along the line C3-C3 of FIG. 4a). In the embodiment of FIG. 4c), the groove 8 surrounds the discharge hole 7 and is formed concentrically with the discharge hole 7, and the edge of the groove 8 and the edge of the discharge hole 7 are in contact with each other. Since the edge of the groove 8 and the edge of the discharge hole 7 are in contact with each other, the discharged solution polymer is pinned at the edge of the discharge hole 7, and the wet spread of the flat surface of the nozzle can be substantially eliminated. FIG. 4d) is a schematic view showing a cross section of the base along the line C4-C4 of FIG. 4c). The angle θ formed by the groove 8 and the flat surface of the nozzle is preferably made small in order to maintain the rigidity of the outer circumference of the discharge hole 7, but it should be 45 ° or more and 60 ° or less in order to improve the liquid drainage at the edge of the groove 8. preferable.

[Second solution spinneret]
Next, an example of the second embodiment of the solution spinneret of the present invention will be described with reference to FIGS. 5 and 6. Since the second solution spinning mouthpiece has the same structure as the first solution spinning mouthpiece except for the form of the discharge hole 7 and the groove 8 on the flat surface 11 of the nozzle plate 2, detailed description of the structure of the mouthpiece is omitted. do.

FIG. 5 is a schematic view showing an embodiment of the second solution spinneret, and is a diagram corresponding to FIG. 2. In the second solution spinneret, the hole diameter D is larger than the width W of the flat surface, and the discharge hole 7 protrudes from the nozzle flat surface 11. A groove 8 is formed between adjacent discharge holes 7 on the flat surface 11 of the nozzle. The number of grooves between adjacent discharge holes is at least one, and a plurality of grooves may be formed. The length of the groove 8 in the X direction is the width W of the flat surface, and the shape of the groove is not limited to a straight line or a curved line. The length W8c of the groove 8 in the Y direction is (sum of adjacent discharge hole intervals P-radius of adjacent discharge holes) or less.

FIG. 6 is a schematic view showing another embodiment of the second solution spinneret, and is a view corresponding to FIGS. 2 and 3a). In the embodiment of FIG. 6a), the discharge hole 7 has a shape in which a part of the circle is missing on the flat surface 11, but is circular when observed from the flat surface 11. The groove 8 is a part of the concentric circles formed on the flat surface 11 by imagining the concentric circles of the discharge holes 7 surrounding the circular discharge holes 7 observed from the flat surface 11. Since the groove 8 approaches the outer periphery of the discharge hole 7, the range in which the discharged solution polymer wets and spreads on the flat surface of the nozzle can be narrowed. FIG. 6b) is a schematic view showing a cross section of the base along the line C5-C5 of FIG. 6a). In the embodiment of FIG. 6c), the groove 8 surrounds the discharge hole 7 and is a part of a concentric circle with the discharge hole 7, and the edge of the groove 8 and the edge of the discharge hole 7 are in contact with each other. Since the edge of the groove 8 and the edge of the discharge hole 7 are in contact with each other, the discharged solution polymer is pinned at the edge of the discharge hole 7, and the wet spread of the flat surface of the nozzle can be substantially eliminated. FIG. 6d) is a schematic view showing a cross section of the base along the line C6-C6 of FIG. 6c). The angle θ formed by the groove 8 and the flat surface of the nozzle is preferably made small in order to maintain the rigidity of the outer circumference of the discharge hole 7, but it should be 45 ° or more and 60 ° or less in order to improve the liquid drainage at the edge of the groove 8. preferable.

Next, a step of discharging the solution polymer from the discharge hole of the solution spinneret of the present invention will be described with reference to FIG. 7.
7a) and 7b) are schematic views showing a process in which the solution polymer 16 is discharged from the discharge hole 7 in the embodiment of FIG. When the solution polymer 16 is discharged from the discharge hole 7, the pressure acting on the solution polymer 16 drops sharply. Therefore, as shown in FIG. 7a), the solution polymer 16 immediately after being discharged from the discharge hole 7 swells roundly due to surface tension. The swollen solution polymer 16 travels along the flat surface 11 of the nozzle in both the X and Y directions, and when it reaches the position of the groove 8, it is pinned at the edge of the groove 8, and the liquid cannot be further wetted and spread and runs out. , As shown in FIG. 7b), the wet spread stops. Since the wet spread range is small, the retention of the solution polymer 16 is suppressed, and stable discharge is possible without precipitating the polymer.

FIG. 7c) is a schematic view showing a process in which the solution polymer 16 is discharged from the discharge hole 7 in the embodiment of FIG. 4c). Since the edge of the discharge hole 7 and the edge of the groove 8 are in contact with each other, there is no flat portion that spreads wet as shown in FIG. 7c), and the most stable discharge is possible.

7d) and 7e) are schematic views showing a process in which the solution polymer 16 is discharged from the discharge hole 7 in the embodiment of FIG. When the solution polymer 16 is discharged from the discharge hole 7, the X direction is pinned to the edge of the discharge hole and swells along the edge. Therefore, in the embodiment of FIG. 5, the groove in the X direction is unnecessary, and the second solution spinning base has a shape that is easier to manufacture than the first solution spinning base, and the manufacturing cost of the base can be reduced. In the Y direction, as shown in FIG. 7d), the liquid wets and spreads along the flat surface 11 of the nozzle. When the position of the groove 8 is reached, the liquid cannot be further wet and spread and runs out, and as shown in FIG. 7e), the wet spread stops. Since the wet spread range is small, the retention of the solution polymer is suppressed, and stable discharge is possible without precipitating the polymer.

Next, a process in which the solution polymer discharged from the discharge hole of the solution spinneret of the present invention is stretched by high-speed air will be described with reference to FIG.

FIG. 8a) is a schematic view showing a process in which the solution polymer 16 is discharged from the discharge hole 7 from the discharge hole 7 in the step of FIG. 7a) b) and then stretched by high-speed air in the embodiment of FIG. High-speed air is ejected from the air nozzle 12 along the nozzle tip 15, and the high-speed air is separated from the slope of the nozzle tip 15 and sprayed onto the discharged solution polymer to stretch the solution polymer. High-speed air does not flow directly to the triangular portion formed by the extension line of the nozzle tip 15 and the flat surface 11 of the nozzle shown by the broken line in FIG. 8a), and the state is close to vacuum. It may become unstable.

FIG. 8b) is a schematic view showing a process in which the solution polymer 16 is discharged from the discharge hole 7 from the discharge hole 7 in the step of FIG. 7d) e) and then stretched by high-speed air in the embodiment of FIG. In the embodiment of FIG. 8b), since the discharge hole 7 is formed on the slope of the nozzle tip 15, the high-speed air ejected from the air nozzle 12 is directly blown onto the polymer solution, and there is no vacuum portion as in FIG. 8a). Stable discharge is possible, and the diameter of the polymer fiber can be reduced efficiently. Therefore, the second solution spinneret can reduce the amount of high-speed air as compared with the first solution spinneret, and can reduce the suction load of the polymer fiber collecting portion. In particular, when the suction capacity of the collecting part is low, there is a concern that the polymer fibers may fly up at the collecting part and become foreign substances mixed in the product, but the second solution spinneret should reduce the amount of high-speed air. The risk of foreign matter generation can be suppressed.

Spinning was carried out in the embodiment of FIG. 4c).
The nozzle plate 2 had a width of 200 mm in the Y direction, a nozzle tip angle of 30 degrees, and a width W of the flat surface 11 at the tip of the nozzle of 1.2 mm. On the flat surface 11, 45 circular discharge holes 7 having a hole diameter D = 0.4 mm were formed at adjacent discharge hole intervals P = 3.5 mm. Further, on the flat surface 11, circular grooves 8 having a width of 0.2 mm and a depth of 0.17 mm are formed around each discharge hole 7 so that the edge of the discharge hole 7 and the edge of the groove 8 are in contact with each other. rice field. The angle θ formed by the groove 8 and the flat surface 11 was 60 °. The base plate 3 was formed with one polymer supply port 9 having a diameter of 6 mm, a circular manifold 5 having a radius of 10 mm, and a slit 6 having a length of 10 mm. By assembling the nozzle plate 2 and the base plate 3, a polymer flow path was formed. Further, the air lip plate 4 was assembled to the base plate 3, and the gap between the air nozzle 12 and the nozzle tip 15 was set to 0.8 mm by adjusting the assembly to form a mouthpiece.

A solution polymer having a viscosity of 5000 mPa · s, in which polyvinyl alcohol was dissolved in water at 20% by mass, was supplied from the polymer supply port 9 at 20 mL / min. While discharging the solution polymer from the discharge hole 7, the solution polymer was blown with air at a flow rate of 1500 L / min from the air nozzles on both sides, and the solution polymer was stretched and spun. Even after spinning for 10 hours continuously, the discharge hole 7 was not clogged. When the fiber diameter of the obtained non-woven fabric was measured with an electron microscope, the average fiber diameter was 3.52 μm.

The solution spinning base of the present invention can be used not only for spinning non-woven fabrics but also for solution spinning for various purposes.

1: Solution spinneret 2: Nozzle plate 3: Base plate 4: Air lip plate 5: Manifold 6: Slit 7: Discharge hole 8: Groove 9: Polymer supply port 10: Polymer introduction path 11: Nozzle flat surface 12: Air nozzle 13 : Blow air supply port 14: Blow rectifying hole 15: Nozzle tip 16: Solution polymer

Claims (5)

A spinneret that discharges a solution
Has a flat surface at the tip of the base,
A solution spinneret in which a plurality of discharge holes for discharging a solution having a size that fits in the flat surface and grooves surrounding the respective discharge holes are formed on the flat surface. The solution spinneret according to claim 1, wherein the discharge hole is circular and the groove has a concentric shape surrounding the discharge hole. A spinneret that discharges a solution
Has a flat surface at the tip of the base,
At the tip of the mouthpiece, a plurality of discharge holes for discharging a solution having a size protruding from the flat surface are formed.
A solution spinneret in which a groove is formed between adjacent discharge holes on the flat surface. The shape of the discharge hole observed from the flat surface is circular.
The solution spinneret according to claim 3, wherein the groove has a shape of a part of concentric circles surrounding the discharge hole. The solution spinneret according to any one of claims 1 to 4, wherein the edge of the discharge hole and the edge of the groove are in contact with each other.

Images