JP7259384B2 - Meltblown mouthpiece - Google Patents

Description

The present invention relates to a melt-blowing spinneret for spinning a non-woven fabric, and more particularly to a melt-blowing spinneret with improved assembling and cleaning properties.

In recent years, non-woven fabrics with micron-order to nano-order fiber diameters have been used in various fields such as sanitary materials such as filters, diapers, and masks, medical materials, and pharmaceutical applications. Techniques for producing these nonwoven fabrics generally include the meltblowing method, the spunbond method, and the electrospinning method, and the production method is selected according to the intended use of the product. Among them, the melt blowing method can produce fibers with a fiber diameter of about 1 μm, and is used in many applications. In the melt-blowing method, a melted or dissolved polymer is extruded from a nozzle, and the ejected polymer is stretched by high-speed air ejected from the periphery of the nozzle to form fibers. As shown in Patent Documents 1 and 2, the die used in the melt blowing method generally has a configuration in which a coat-hanger type manifold plate is installed on the nozzle plate for discharging the polymer to spread and homogenize the independent polymer in the width direction. used for

JP-A-6-166944 Japanese Patent No. 6246055

However, the nozzles disclosed in Patent Document 1 and Patent Document 2 have a shape in which the manifold plate is divided into two parts, and the width of the opening into which the polymer flows in the connected nozzle plate and the polymer expanded by the manifold are divided. The guiding slits must have the same width. Also, in order to equalize the flow rate, it is necessary to increase the capacity of the manifold to equalize the flow rate. As a result, the mouthpiece itself becomes large, and accompanying work such as disassembly, cleaning, and assembly of the mouthpiece becomes complicated and requires a great deal of labor.

To provide a melt-blown nozzle which can be miniaturized by reducing the number of parts while maintaining polymer fluidity and uniformity equivalent to those of the prior art, and which can reduce incidental work such as disassembly, cleaning, and assembly.

The melt-blown nozzle of the present invention, which solves the above problems,
having an adjacent nozzle plate and base plate;
The nozzle plate includes a series of recesses, a plurality of nozzle holes, which are part of a manifold for widening the polymer formed on the surface facing the base plate and part of a slit for rectifying the polymer, and having a polymer introduction path that communicates between the nozzle hole and the portion of the recess that constitutes the slit,
The base plate has a polymer supply port through which a polymer is supplied, and a polymer supply channel that communicates between the polymer supply port and a surface facing the nozzle plate and opens into a portion of the recess that constitutes the manifold,
having an air nozzle for blowing air toward the polymer discharged from the plurality of nozzles;
The manifold and the slit are formed by the surface of the base plate facing the nozzle plate and the recess.

The melt-blown nozzle of the present invention preferably has an air lip plate spaced apart from the nozzle plate, and the air nozzle comprises a gap between the nozzle plate and the air lip plate, More preferably, the base plate has a blow air supply section communicating with the air nozzle.

In the melt-blown nozzle of the present invention, the base plate preferably has an air vent that communicates the outside with the polymer introduction path.

According to the spinneret of the present invention, the number of parts constituting the spinneret can be reduced and the size can be reduced without reducing the fluidity and uniformity of the polymer flowing inside the spinneret. Incidental work such as

1 is a schematic diagram showing a configuration cross section of a melt-blown nozzle of the present invention. FIG. Schematic diagram showing air flowing into the polymer in the embodiment of FIG. FIG. 2 is a schematic diagram showing a process of filling the inside of the die with a polymer in the embodiment of FIG. 1; Figure 2 shows the fiber distribution spun in the embodiment of Figure 1;

Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these.

First, an embodiment of the melt-blown nozzle of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing a structural cross section of the melt-blown nozzle of the present invention.

Please refer to FIG. The melt blow nozzle of the present invention comprises a nozzle plate 2 for discharging a polymer, a base plate 3 for supplying blow air for stretching the polymer, and an air nozzle 13 for rectifying the blow air. Each component will be described in detail below.

On the nozzle plate 2, a manifold 5 for widening the polymer and a slit 6 for rectifying the polymer are formed as a series of recesses on the surface facing the base plate 3. As shown in FIG. By connecting the surface of the nozzle plate 2 excluding the manifold 5 and the slit 6 to the base plate 3, the manifold 5 and the slit 6 form a series of closed recesses, allowing the polymer to flow. The manifold 5 and the slit 6 are shaped so that the polymer can flow uniformly according to the viscosity of the polymer and the flow rate of the polymer. The manifold 5 is a portion for widening the inflowing polymer, and the semicircular concave portion has a uniform shape in the Y direction in FIG. However, the shape is not limited to a semicircular shape, as long as it is a shape that spreads the polymer uniformly. Moreover, in order to improve fluidity of the liquid, it is preferable that the surface roughness of the manifold 5 is Ra 0.2 or less. In order for the slit 6 to uniformly rectify the polymer widened by the manifold 5, it is preferable that the concave portion is processed to have a flatness of 0.005 or less so as to have a uniform shape in the Y direction of FIG. is preferably Ra 0.2 or less. A series of concave portions of the manifold 5 and the slit 6 communicate with a polymer introduction path 19 that introduces the polymer into the plurality of nozzle holes 7 . The hole diameter D of the nozzle hole 7 is determined in consideration of the pressure loss due to the polymer viscosity and the hole length L. It is preferable to reduce the amount of polymer discharged per hole, and the hole diameter D is preferably 100 μm to 400 μm. With the above configuration, the nozzle plate 2 has two functions of ejecting the polymer and expanding the width of the polymer uniformly in the die width direction.

As described above, the base plate 3 faces the nozzle plate 2 and is directly fastened to the nozzle plate 2 with the bolts 11 by metal touch, so that the polymer flows in the series of concave portions of the manifold 5 and the slit 6 of the nozzle plate 2. Construct a closed space. The base plate 3 has a polymer supply port 8 for supplying polymer to the nozzle plate 2 . The polymer supply port 8 communicates with the nozzle plate 2 facing the base plate 3 via the polymer supply path 10 and supplies the polymer to the manifold 5 . Moreover, it is preferable that the polymer supply port 8 is arranged so as to communicate with the manifold 5 , and that all the polymer flow paths are arranged above the manifold 5 . Although the shape of the polymer supply channel 10 is not limited, it is preferably a round hole that is relatively easy to process.

The polymer flowing from the polymer supply port 8 flows through the polymer supply path 10, the manifold 5, the slit 6, and the polymer introduction path 19, is discharged from the discharge hole 7, and is stretched and opened by the high-speed air blown from the air nozzle 13. It becomes fine and fibrous.

The air nozzle 13 adjusts the wind speed of the air in the gap between the air lip plate 4 and the nozzle tip 15 of the nozzle plate 2 . The air lip plate 4 is preferably bolted to the base plate 3 so that the gap between the air nozzles 13 can be adjusted. Further, if the gap between the air nozzles 13 is not constant, the blow wind speed will be uneven, the polymer discharged from the nozzle hole 7 will be stretched unevenly, and the fiber diameter will be uneven. Therefore, it is preferable to adjust the gap between the air nozzles 13 so as to be uniform in the Y direction in FIG. 1, and the deviation of the gap is preferably 10 μm or less.

The base plate 3 is provided with a blow air supply section 9 communicating with the air nozzle 13 . Two blow air supply units 9 are provided in the nozzle plate 2 in order to uniformly apply blow air to the polymer discharged from the nozzle holes 7 from both sides of the nozzle tip 15 of the nozzle plate 2 . Moreover, it is preferable that the supplied blow air is uniformly dispersed in a large number of blow regulating holes 14 and communicated with the air nozzles 13 .

In addition, it is preferable that the base plate 3 is formed with an air vent 12 in order to remove air mixed in when the polymer is supplied. FIG. 2 is a schematic diagram showing air flowing into the polymer, and the air vent 12 communicates with the polymer introduction channel 19 in order to discharge the air 16 accumulated in the polymer introduction channel 19 . Although the number of air vents 12 is not limited, it is preferable that two air vents 12 are arranged at both ends because stagnant air 16 tends to accumulate at the ends of the polymer introduction path 19. More preferably, it is arranged above the introduction path 19 .

Next, the process of filling the polymer inside the spinneret of the present invention will be described with reference to FIG.
3a) to 3d) are schematic diagrams showing the process of filling the inside of the die with a polymer in the embodiment of FIG. FIG. 3 a ) shows the flow of polymer 17 into the polymer feed channel 10 . FIGS. 3b) to 3c) show the process in which the polymer 17 flows into the manifold 5 from the state of FIG. In order to spread the width of the polymer 17 quickly and uniformly, the shape of the manifold 5 is reduced by flow calculation, thereby shortening the residence time of the polymer 17 in the manifold. Furthermore, by rectifying the polymer 17 in the gaps formed by the slits 6, the polymer can be uniformly extruded over the entire width of the die.

Next, FIGS. 3d) to 3f) show the steps in which the polymer 17 uniformly rectified from the slit 6 in FIG.

Since the polymer 17 that has flowed in fills the upper portion of the air vent 12 from the lower portion of the polymer introduction passage 19 having the nozzle hole 7, the air space 18 of the polymer introduction passage 19 is gradually introduced to the air vent 12 as the polymer 17 is filled. On the other hand, it is possible to prevent air from entering the polymer and air from remaining inside the die.

Spinning was carried out in the embodiment of FIG.
The width of the nozzle plate 2 in the Y direction was set to 200 mm, and 100 nozzle holes 7 having a hole diameter D of 0.3 mm were formed at a pitch of 1.5 mm in the nozzle tip 15 having a tip angle of 60 degrees. The slit 5 has a length of 10 mm and a gap of 0.5 mm. The manifold 5 has a semicircular shape with a radius of 10 mm. A flow path was formed by assembling the base plate 3 . Also, by adjusting the assembly of the base plate 3 and the air lip 4, the gap between the air nozzle 13 and the nozzle tip 15 was set to 0.8 mm to construct the mouthpiece.

A polymer having a viscosity of 1000 mPa·s, which is obtained by dissolving 12 wt % of polylactic acid in ethyl acetate, was supplied from the polymer supply port 8 at a flow rate of 30 m/min. While the polymer was being discharged from the discharge hole 7, the polymer was drawn and spun by blowing air at a flow rate of 1000 L/min from one air nozzle. When the fiber diameter of the obtained nonwoven fabric was measured with an electron microscope, the average fiber diameter was 0.47 μm as shown in FIG.

INDUSTRIAL APPLICABILITY In the present invention, by reducing the number of spinneret parts while making the flow of the polymer uniform, the ancillary work of disassembling, cleaning, and assembling the spinneret can be reduced, and the spinneret can be used as a spinneret capable of stable spinning. can.

1 Melt blow nozzle 2 Nozzle plate 3 Base plate 4 Air lip 5 Manifold 6 Slit 7 Nozzle hole 8 Polymer supply port 9 Blow air supply port 10 Polymer supply path 11 Bolt 12 Air vent 13 Air nozzle 14 Blow rectifying hole 15 Nozzle tip 16 Mixed air 17 Polymer 18 Air space 19 Polymer introduction path D Pore diameter
L hole length

Claims (5)

having an adjacent nozzle plate and base plate;
The nozzle plate is part of a manifold for widening the polymer formed on the surface facing the base plate and part of a slit having a uniform shape in the width direction for rectifying the widened polymer. having a series of recesses, a plurality of nozzle holes, and a polymer introduction path that communicates between the nozzle holes and the slits of the recesses,
The base plate has a polymer supply port through which a polymer is supplied, and a polymer supply path that communicates between the polymer supply port and a surface facing the nozzle plate and opens into a portion of the recess that constitutes the manifold,
having an air nozzle for blowing air toward the polymer discharged from the plurality of nozzles;
A melt-blown nozzle, wherein the manifold and the slit are composed of a surface of the base plate facing the nozzle plate and the recess. Having an air lip plate spaced apart from the nozzle plate,
2. The meltblown nozzle of claim 1, wherein said air nozzle is configured in the gap between said nozzle plate and said air lip plate. 3. The meltblowing nozzle of claim 2, wherein said base plate has a blow air supply in communication with said air nozzle. The melt-blown nozzle according to any one of claims 1 to 3, wherein said base plate has air vents communicating between the outside and both ends of said polymer introduction path. The meltblown nozzle according to any one of claims 1 to 4, wherein the flatness of the slits of the nozzle plate is 0.005 or less.

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