JP2021063321A - Device for producing nanofiber - Google Patents

Abstract

To provide a device capable of stably producing nanofibers.SOLUTION: A device 112 for producing nanofibers includes a resin discharge member (resin discharge nozzle 118) for discharging a molten resin from a discharge port 122, a heat insulation gas jetting member (heated steam nozzle 146) for jetting heat insulation gas of temperature higher than atmospheric temperature from a heat insulation gas jetting port 136 toward the molten resin discharged from the discharge port 122, and a drawing gas jetting member (high-speed high-temperature air nozzle 138) for jetting drawing gas of temperature higher than atmospheric temperature from a drawing gas jetting port 144 toward the molten resin in the same position as the heat insulation gas jetting port 136 in a discharge direction of the molten resin.SELECTED DRAWING: Figure 1

Description

The present application relates to a nanofiber manufacturing apparatus.

Patent Document 1 describes a nanofiber manufacturing apparatus having a structure in which a molten polymer discharged from a ejection nozzle is stretched by high-speed air from an air nozzle.

Japanese Unexamined Patent Publication No. 2016-156114

The technique described in Patent Document 1 has a structure in which the discharged molten polymer is simply merged with high-speed air and stretched. However, when the molten polymer is actually stretched to produce nanofibers, the nanofibers are twisted. Stable production is required.

The purpose of the present application is to obtain a nanofiber manufacturing apparatus capable of more stably manufacturing nanofibers.

In the first aspect, a resin discharge member that discharges the molten resin from the discharge port and a heat-retaining gas injection that injects a heat-retaining gas having a temperature higher than the atmosphere from the heat-retaining gas injection port toward the molten resin discharged from the discharge port. It includes a member and a stretched gas injection member that injects a stretched gas having a temperature higher than the atmosphere from a stretched gas injection port at the same position as the heat retaining gas injection port toward the molten resin in the discharge direction of the molten resin.

In this nanofiber manufacturing apparatus, the heat insulating gas is injected from the heat insulating gas injection port of the heat insulating gas injection member toward the molten resin discharged from the discharge port of the resin discharge member, and stretched from the stretched gas injection port of the stretched gas injection member. Inject gas. The heat-retaining gas has a higher temperature than the atmosphere, and when the high-temperature heat-retaining gas comes into contact with the molten resin, the viscosity of the molten resin is maintained in a lowered state. Since the stretched gas is also hotter than the atmosphere, the molten resin can be stretched while maintaining a state in which the viscosity of the molten resin is lowered.

The stretched gas is injected from the stretched gas injection port and approaches the molten resin. The heat-retaining gas is injected from the heat-retaining gas injection port and approaches the molten resin. Here, the stretched gas injection port is at the same position as the heat retaining gas injection port in the discharge direction of the molten resin. Therefore, the heat retaining gas and the stretched gas come into contact with each other at substantially the same position in the discharge direction of the molten resin. That is, it is possible to prevent the heat retaining gas and the stretched gas from coming into contact with the molten resin at different positions (shifted positions) when viewed in the discharge direction. In other words, in terms of time, it is possible to prevent either the heat retaining gas or the stretched gas from coming into contact with the molten resin first. Since it is possible to suppress that the influence of the gas that has come into contact with the molten resin first among the heat insulating gas and the stretched gas becomes dominant, the shape of the obtained nanofibers is stable.

In the second aspect, in the first aspect, the heat retaining gas injection port and the stretched gas injection port surround the discharge port when viewed in the discharge direction of the molten resin from the discharge port, respectively.

Since the heat-retaining gas injection port surrounds the discharge port, the heat-retaining gas can be reliably brought into contact with the molten resin discharged from the discharge port.

Since the stretched gas injection port surrounds the discharge port, the stretched gas can be sprayed around the molten resin that has passed through the surrounding area to stretch the molten resin.

In the third aspect, in the second aspect, the heat retaining gas injection port is located outside the stretched gas injection port when viewed along the discharge direction.

As a result, since the heat-retaining gas surrounds the stretched gas and the molten resin, not only the molten resin but also the stretched gas can be kept warm with the heat-retaining gas. Since the stretched gas is injected inside the heat retaining gas, that is, at a position close to the molten resin, the stretched gas can be reliably brought into contact with the molten resin to stretch the molten resin.

In the fourth aspect, in the first aspect, the nozzle having both the heat retaining gas injection port and the stretched gas injection port is provided.

As a result, it is not necessary to separately provide the nozzle provided with the heat-retaining gas injection port and the nozzle provided with the stretched gas injection port, so that the structure of the nanofiber manufacturing apparatus can be simplified. Further, since the nozzle that also serves as an injection port has a heat-retaining gas injection port and a stretched gas injection port, the relative positions of the heat-retaining gas injection port and the stretched gas injection port can be maintained constant.

In the fifth aspect, in any one of the first to fourth aspects, the injection direction of the stretched gas from the stretched gas injection port is inclined so as to be asymptotic to the molten resin discharged from the discharge port. doing.

As a result, the jet gas comes into close contact with the molten resin discharged from the discharge port, so that thinner nanofibers can be obtained.

In the sixth aspect, in any one of the first to fifth aspects, the injection direction of the heat insulating gas from the heat insulating gas injection port is inclined so as to be asymptotic to the molten resin discharged from the discharge port. doing.

As a result, the heat-retaining gas comes into close contact with the molten resin discharged from the discharge port, so that the molten resin can be kept warm more effectively.

In the present application, nanofibers can be stably produced.

FIG. 1 is a cross-sectional view showing the nanofiber manufacturing apparatus of the first embodiment. FIG. 2 is a perspective view showing a filter manufacturing apparatus including the nanofiber manufacturing apparatus of the first embodiment. FIG. 3 is a sectional view taken along line III-III of FIG. 1 showing the nanofiber manufacturing apparatus of the first embodiment. FIG. 4 is an end view of the nanofiber manufacturing apparatus of the first embodiment as viewed in the direction of arrow IV in FIG. FIG. 5 is a cross-sectional view showing a state in which the molten resin is discharged in the nanofiber manufacturing apparatus of the first embodiment. FIG. 6 is a cross-sectional view showing a state in which the heat insulating gas is injected while discharging the molten resin in the nanofiber manufacturing apparatus of the first embodiment. FIG. 7 is a cross-sectional view showing a state in which the heat insulating gas and the ejected gas are ejected while discharging the molten resin in the nanofiber manufacturing apparatus of the first embodiment. FIG. 8 is a cross-sectional view showing the nanofiber manufacturing apparatus of the second embodiment. FIG. 9 is a cross-sectional view showing a state in which the molten resin is discharged in the nanofiber manufacturing apparatus of the second embodiment. FIG. 10 is a cross-sectional view showing a state in which the heat insulating gas is injected while discharging the molten resin in the nanofiber manufacturing apparatus of the second embodiment. FIG. 11 is a cross-sectional view showing a state in which a stretched gas and a heat retaining gas are ejected while discharging the molten resin in the nanofiber manufacturing apparatus of the second embodiment. FIG. 12 is a cross-sectional view showing the nanofiber manufacturing apparatus of the third embodiment. FIG. 13 is a cross-sectional view showing a state in which the molten resin is discharged in the nanofiber manufacturing apparatus of the third embodiment. FIG. 14 is a cross-sectional view showing a state in which the heat insulating gas is injected while discharging the molten resin in the nanofiber manufacturing apparatus of the third embodiment. FIG. 15 is a cross-sectional view showing a state in which a stretched gas and a heat retaining gas are ejected while discharging the molten resin in the nanofiber manufacturing apparatus of the third embodiment. FIG. 16 is a cross-sectional view showing the nanofiber manufacturing apparatus of the fourth embodiment. FIG. 17 is a cross-sectional view showing a state in which the molten resin is discharged in the nanofiber manufacturing apparatus of the fourth embodiment. FIG. 18 is a cross-sectional view showing a state in which the heat insulating gas is injected while discharging the molten resin in the nanofiber manufacturing apparatus of the fourth embodiment. FIG. 19 is a cross-sectional view showing a state in which a stretched gas and a heat retaining gas are ejected while discharging a molten resin in the nanofiber manufacturing apparatus of the fourth embodiment. FIG. 20 is an end view of the nanofiber manufacturing apparatus of the first modification in the same direction as in FIG. FIG. 21 is an end view of the nanofiber manufacturing apparatus of the second modified example as viewed in the same direction as in FIG. FIG. 22 is a cross-sectional view showing a nanofiber manufacturing apparatus of the first comparative example.

Hereinafter, the nanofiber manufacturing apparatus 112 of the first embodiment and the filter manufacturing apparatus 82 provided with the nanofiber manufacturing apparatus 112 will be described with reference to the drawings.

As shown in FIG. 1, the nanofiber manufacturing apparatus 112 has a discharge unit 114. As shown in detail in FIG. 2, the discharge unit 114 has an elongated block 116. The block 116 is provided with a plurality of resin discharge nozzles 118 at regular intervals in the longitudinal direction of the block 116 (direction of arrow L1).

The resin discharge nozzle 118 is a tubular member having the above-mentioned resin flow path 124 at a central portion (indicated by the center line CL-1).

A resin supply pipe 120 is connected to the block 116, and the molten resin MR is supplied from a resin supply member (not shown). As shown in FIG. 5, the molten resin MR is discharged downward from the discharge port 122 at the lower end through the resin flow path 124 of the resin discharge nozzle 118. The resin flow path 124 is a linear hollow portion that goes downward in the resin discharge nozzle 118.

In the following, the terms "upstream" and "downstream" simply mean "upstream" and "downstream" in the discharge direction of the molten resin MR from the discharge port 122, respectively. The upper side in FIG. 1 is the upstream side, and the lower side is the downstream side.

As shown in detail in FIG. 1, the nanofiber manufacturing apparatus 112 of the first embodiment is provided with the first tubular member 128 and the second tubular member 130 corresponding to each of the plurality of resin discharge nozzles 118. And has a third tubular member 132.

The first tubular member 128 is provided in a one-to-one correspondence with the resin discharge nozzle 118, and is fixed at the same core as the resin discharge nozzle 118. The first tubular member 128 has a first cylindrical portion 128A surrounding the resin discharge nozzle 118, and a first truncated cone portion 128B extending from the lower end (downstream end) of the first cylindrical portion 128A. There is.

The first cylindrical portion 128A is formed in a cylindrical shape. On the other hand, the first truncated cone portion 128B has a tapered shape that extends downstream from the first cylindrical portion 128A and is inclined in a truncated cone shape toward the center line CL-1.

The first truncated cone portion 128B of the first tubular member 128 extends further downstream than the downstream end 118C of the resin discharge nozzle 118, and the downstream end 118C and the first truncated cone portion 128B of the resin discharge nozzle 118. It forms an enclosed area 142 surrounded by.

A gap GP-1 is formed between the outer peripheral surface of the resin discharge nozzle 118 and the inner peripheral surface of the first cylindrical portion 128A, and the gap GP-1 is an air nozzle 126. Air is supplied to the air nozzle 126 through the air supply pipe 134 shown in FIG. This air is injected into the surrounding area 142.

The second tubular member 130 is provided in a one-to-one correspondence with the first tubular member 128 and the resin discharge nozzle 118, and is fixed at the same core as the first tubular member 128 and the resin discharge nozzle 118. The second cylindrical member 130 has a second cylindrical portion 130A surrounding the first cylindrical portion 128A, and a second truncated cone portion 130B extending from the lower end (downstream end) of the second cylindrical portion 130A. ing.

The second cylindrical portion 130A is formed in a cylindrical shape, whereas the second truncated cone portion 130B extends downstream from the second cylindrical portion 130A and is a truncated cone toward the center line CL-1. It has a tapered shape that slopes like a cylinder.

A gap GP-2 is formed between the outer peripheral surface of the first tubular member 128 and the inner peripheral surface of the second tubular member 130, and this gap GP-2 is a high-speed high-temperature air nozzle 138. .. High-speed high-temperature air is supplied to the high-speed high-temperature air nozzle 138 through the high-speed high-temperature air supply pipe 140 shown in FIG. The high-speed high-temperature air is a gas having a higher flow speed than the air supplied to the air nozzle 126 and a higher temperature than the gas (air) around the nanofiber manufacturing apparatus 112.

Since both the first truncated cone portion 128B and the second truncated cone portion 130B are inclined in a truncated cone shape toward the center line CL-1, the high-speed high-temperature air nozzle 138 also has a center line in the downstream portion. The shape is inclined toward CL-1.

The downstream end 130C of the second tubular member 130 is at the same position as the downstream end 128C of the first tubular member 128 in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122.

The region between the downstream end 130C of the second tubular member 130 and the downstream end 128C of the first tubular member 128 is a stretched gas injection port 144 in which high-speed high-temperature air is injected as stretched gas EA from the high-speed high-temperature air nozzle 138. is there.

The stretched gas injection port 144 surrounds the discharge port when viewed in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122. The injection direction of the stretched gas EA from the stretched gas injection port 144 is inclined so as to be asymptotic to the molten resin MR (see FIG. 5) discharged from the discharge port 122. Therefore, the stretched gas EA jetted from the stretched gas injection port 144 approaches the molten resin MR discharged from the discharge port 122 toward the downstream side.

The third tubular member 132 is provided in a one-to-one correspondence with the second tubular member 130, the first tubular member 128, and the resin discharge nozzle 118, and the second tubular member 130, the first tubular member 128, and the resin discharge nozzle 118 are provided. It is fixed at the same core as the resin discharge nozzle 118. The third cylindrical member 132 has a third cylindrical portion 132A surrounding the second cylindrical portion 130A, and a third truncated cone portion 132B extending from the lower end (downstream end) of the third cylindrical portion 132A. ing.

The third cylindrical portion 132A is formed in a cylindrical shape. On the other hand, the third truncated cone portion 132B has a tapered shape that extends downstream from the third cylindrical portion 132A and is inclined in a truncated cone shape toward the center line CL-1.

A gap GP-3 is formed between the outer peripheral surface of the second tubular member 130 and the inner peripheral surface of the third tubular member 132, and the gap GP-3 is a heated steam nozzle 146. The heated steam is supplied to the heated steam nozzle 146 through the heated steam supply pipe 148 shown in FIG. The heated steam is a gas having a higher humidity than the high-speed high-temperature air supplied to the high-speed high-temperature air nozzle 138 and a higher temperature than the gas (air) around the nanofiber manufacturing apparatus 112. In the present embodiment, the injection pressure of the stretching gas EA is set higher than the injection pressure of the heat retaining gas HA.

Since both the second truncated cone portion 130B and the third truncated cone portion 132B are inclined in a truncated cone shape toward the center line CL-1, the heated steam nozzle 146 is also inclined toward the center line CL-1. It is a shape to be used.

The downstream end 132C of the third tubular member 132 is at the same position as the downstream end 130C of the second tubular member 130 in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122.

The region between the downstream end 132C of the third tubular member 132 and the downstream end 130C of the second tubular member 130 is a heat insulating gas injection port 136 in which pressurized steam is injected as heat insulating gas HA from the heated steam nozzle 146.

The heat-retaining gas injection port 136 surrounds the discharge port when viewed in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122. The injection direction of the heat-retaining gas HA from the heat-retaining gas injection port 136 is inclined so as to be asymptotic to the molten resin MR (see FIG. 5) discharged from the discharge port 122. Therefore, the heat-retaining gas HA injected from the heat-retaining gas injection port 136 approaches the molten resin MR discharged from the discharge port 122 toward the downstream side.

Further, the heat retaining gas injection port 136 is located outside the stretched gas injection port 144 when viewed in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122.

In the discharge direction of the molten resin MR from the discharge port 122 (direction of arrow T1), the downstream end 132C of the third tubular member 132, the downstream end 130C of the second tubular member 130, and the downstream end 128C of the first tubular member 128. Are in the same position. Therefore, the stretched gas injection port 144 and the heat retaining gas injection port 136 are also at the same position in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122.

As shown in FIG. 2, an endless belt 84 is arranged below the discharge unit 114, and is stretched on a plurality of tension rollers 86. In FIG. 2, the endless belt 84 is partially shown, and only one tension roller 86 is shown.

A support 88 is arranged on the flat portion of the endless belt 84 so that the support 88 can be wound by the winding roll 90. The thin linear molten resin MR discharged from the resin discharge nozzle 118 is supported so as to be woven on the support 88 as the support 88 moves in the direction of the arrow M1. Then, on the support 88, for example, a non-woven fabric-like filter is formed.

Next, the operation of this embodiment will be described.

In order to manufacture nanofibers by the nanofiber manufacturing apparatus 112 of the first embodiment, first, as shown in FIG. 5, the molten resin MR is discharged from the discharge port 122. The molten resin MR passes through the surrounding region 142 and hangs down toward the downstream side in the discharge direction, that is, the lower side.

In this state, as shown in FIG. 6, the heat-retaining gas HA is injected from the heat-retaining gas injection port 136. The heat-retaining gas HA approaches the molten resin MR discharged from the discharge port 122. At this time, the injection direction of the heat-retaining gas HA is toward the molten resin MR, but the heat-retaining gas HA gradually spreads and approaches and contacts the molten resin MR. The heat-retaining gas HA suppresses the temperature drop of the molten resin MR, so that the viscosity of the molten resin MR is maintained at a low level.

Further, as shown in FIG. 7, the stretched gas EA is injected from the stretched gas injection port 144. The stretched gas EA approaches the molten resin MR discharged from the discharge port 122. At this time, the injection refueling work of the stretched gas EA is in the direction toward the molten resin MR, but the stretched gas EA gradually spreads and approaches and contacts the molten resin MR. The stretched gas EA stretches the molten resin MR downstream to form nanofibers. The formed nanofibers are supported on support 88 (see FIG. 2).

Here, FIG. 22 shows the nanofiber manufacturing apparatus 32 of the first comparative example. The nanofiber manufacturing apparatus 32 of the comparative example has a discharge port 34 for discharging the molten resin MR and an injection port 36 for injecting the stretched gas EA, but the heat-retaining gas HA (see FIG. 6 and FIG. 7). There is no injection port for injecting. Therefore, in the nanofiber manufacturing apparatus 32 of the comparative example, the heat insulating gas is not injected.

In the nanofiber manufacturing apparatus 32 of the first comparative example, only the stretched gas EA is sprayed onto the molten resin MR discharged from the discharge port 34. Since the heat-retaining gas is not sprayed on the molten resin MR discharged from the discharge port 34, when the stretched gas EA is sprayed while the viscosity of the molten resin MR is high, the molten resin MR is effectively stretched and the nanofibers are blown. There is a limit to how thin it can be.

On the other hand, in the nanofiber manufacturing apparatus 112 of the first embodiment, not only the stretched gas EA but also the heat-retaining gas HA is injected onto the molten resin MR elongated from the discharge port 122. The heat-retaining gas HA suppresses the temperature decrease of the molten resin MR, and maintains the state in which the viscosity of the molten resin MR is decreased. Then, since the stretched gas EA is injected into the molten resin MR whose viscosity has been lowered in this way, the molten resin MR is stretched more finely as compared with the configuration in which the stretched gas EA is jetted in a state where the viscosity is not lowered. It is possible to form finer nanofibers.

Moreover, in the present embodiment, the stretched gas EA is also hotter than the gas around the nanofiber manufacturing apparatus 112. Therefore, as compared with the configuration in which the stretched gas EA has the same temperature as the gas around the nanofiber manufacturing apparatus 112, for example, it is easy to suppress the temperature decrease of the molten resin MR and maintain the viscosity in a low state.

In the present embodiment, the stretched gas injection port 144 is at the same position as the heat retaining gas injection port 136 in the discharge direction of the molten resin MR from the discharge port 122. Here, for example, a configuration in which the stretched gas injection port is on the upstream side of the heat retaining gas injection port in the discharge direction of the molten resin MR from the discharge port 122 is assumed as a second comparative example. In the configuration of the second comparative example, the stretched gas comes into contact with the molten resin on the upstream side in the discharge direction of the molten resin with respect to the heat retaining gas. In other words, the stretched gas comes into contact with the molten resin in time before the heat retaining gas. That is, there is a possibility that the stretched gas comes into contact with the molten resin in a state where the viscosity of the molten resin is not sufficiently lowered, and there is a limit to effectively stretching the molten resin to make the nanofibers thinner.

Further, as a third comparative example, it is assumed that the heat retaining gas injection port is on the upstream side of the stretched gas injection port in the discharge direction of the molten resin MR from the discharge port 122. In the configuration of the third comparative example, the heat insulating gas comes into contact with the molten resin on the upstream side in the discharge direction of the molten resin with respect to the stretched gas. In other words, the heat-retaining gas comes into contact with the molten resin in time before the stretched gas. In this way, when the heat-retaining gas comes into contact with the molten resin before the stretched gas, a time elapses between the time the viscosity of the molten resin is lowered by the heat-retaining gas and the time it is stretched by the stretched gas. It can be difficult to control in terms of how to stretch the.

That is, in the configuration in which the stretched gas injection port and the heat insulating gas injection port are not at the same position in the discharge direction of the molten resin MR from the discharge port 122 as in the second comparative example and the third comparative example, first ( The influence of the gas in contact with the molten resin MR (on the upstream side in the discharge direction of the molten resin) becomes dominant. As a result, it may be difficult to effectively stretch the molten resin. However, in the present embodiment, the stretched gas injection port 144 is located at the same position as the heat retaining gas injection port 136 in the discharge direction of the molten resin MR from the discharge port 122, and the stretched gas EA and the heat retaining gas HA are arranged with respect to the molten resin MR. Contact at virtually the same time. Therefore, the effect of suppressing the influence of the gas that has come into contact with the molten resin MR from becoming dominant and effectively stretching the molten resin MR, that is, the effect of thinning the nanofibers is high.

In the discharge direction of the molten resin MR, the stretched gas injection port 144 is "at the same position" as the heat retaining gas injection port 136, as described above, with respect to the molten resin MR discharged from the discharge port 122. It is sufficient that the stretched gas EA and the heat retaining gas HA come into contact with each other at substantially the same position in the discharge direction.

Next, the nanofiber manufacturing apparatus of the second embodiment will be described. In the second embodiment, the same elements, members, and the like as in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, since the filter manufacturing apparatus provided with the nanofiber manufacturing apparatus of the second embodiment has the same structure as that of the first embodiment, the illustration is omitted.

As shown in FIG. 8, in the nanofiber manufacturing apparatus 212 of the second embodiment, the block 216 of the discharge unit 214 is divided into upper and lower parts. In the example shown in FIG. 8, the upper block 216U, the first intermediate block 216M1, the second intermediate block 216M2, and the lower block 216L are divided into three, but they may be divided into four or more.

Through holes 216F, 216G, and 216H penetrating in the vertical direction (thickness direction) are formed in the first intermediate block 216M1, the second intermediate block 216M2, and the lower block 216L. The through hole 216G is concentric with the through hole 216F and has a larger inner diameter than the through hole 216F. The through hole 216H is concentric with the through hole 216G and has a larger inner diameter than the through hole 216G.

In the second embodiment, the resin discharge nozzle 118 extends from the upper part of the first intermediate block 216M1. The resin discharge nozzle 118 is arranged in the through holes 216F, 216G, and 216H, and the downstream end 118C of the resin discharge nozzle 118 is located in the middle portion of the lower block 216L in the thickness direction (arrow T2 direction).

A flange portion 118F having a partially enlarged diameter of the resin discharge nozzle 118 is provided at the upper end of the resin discharge nozzle 118. The flange portion 118F is housed in a recess 216P formed in the first intermediate block 216M1, whereby the resin discharge nozzle 118 is positioned with respect to the first intermediate block 216M1.

Further, in the second embodiment, the first tubular member 128 extends from the upper part of the second intermediate block 216M2. The first tubular member 128 is arranged in the through holes 216G and 216H, and the downstream end 128C of the first tubular member 128 is at the same height as the lower surface 216C of the lower block 216L.

At the upper end of the first cylindrical member 128, a flange portion 128F having a partially enlarged diameter of the first cylindrical portion 128A is provided. The flange portion 128F is housed in a recess 216Q formed in the second intermediate block 216M2, whereby the first tubular member 128 is positioned with respect to the second intermediate block 216M2.

Further, in the second embodiment, the second tubular member 130 extends from the upper part of the lower block 216L. The second tubular member 130 is arranged in the through hole 216H, and the downstream end 130C of the second tubular member 130 is at the same height position as the lower surface 216C of the lower block 216L.

A flange portion 130F that partially expands the diameter of the second cylindrical portion 130A is provided at the upper end of the second tubular member 130. The flange portion 130F is housed in a recess 216R formed in the lower block 216L, whereby the second tubular member 130 is positioned with respect to the lower block 216L.

In the second embodiment, the gap GP-4 between the outer peripheral surface of the second tubular member 130 and the inner peripheral surface of the through hole 216H is the heated steam nozzle 146. Substantially, the lower block 216L also serves as the third tubular member 132 in the first embodiment. Since the lower block 216L is provided with a plurality of through holes 216H side by side, the lower block 216L also has a structure in which a plurality of third tubular members 132 are integrally provided.

Also in the second embodiment, the stretched gas injection port 144 is at the same position as the heat insulating gas injection port 136 in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122.

The nanofiber manufacturing apparatus 212 of the second embodiment having such a configuration can also manufacture nanofibers in the same manner as the nanofiber manufacturing apparatus 112 of the first embodiment.

That is, first, as shown in FIG. 9, the molten resin MR is discharged from the discharge port 122. The molten resin MR hangs down toward the downstream side in the discharge direction, that is, toward the lower side. Then, as shown in FIG. 10, the heat-retaining gas HA is injected from the heat-retaining gas injection port 136 to bring the molten resin MR into a state in which the viscosity is lowered. Further, as shown in FIG. 11, the stretched gas EA is jetted from the stretched gas injection port 144, and the molten resin MR is stretched downstream to form nanofibers.

Also in the nanofiber manufacturing apparatus 212 of the second embodiment, the stretched gas injection port 144 is at the same position as the heat insulating gas injection port 136 in the discharge direction of the molten resin MR from the discharge port 122. Since the stretched gas EA and the heat-retaining gas HA come into contact with the molten resin MR substantially at the same time, it is possible to suppress that the influence of the gas previously contacted with the molten resin MR becomes dominant. Further, also in the second embodiment, the effect of effectively stretching the molten resin MR, that is, the effect of thinning the nanofibers is high.

In the first embodiment and the second embodiment, the heat insulating gas injection port 136 and the stretched gas injection port 144 surround the discharge port 122 when viewed in the discharge direction of the molten resin MR from the discharge port 122. Therefore, the heat-retaining gas HA and the stretched gas EA can be surrounded and brought into contact with the molten resin MR discharged from the discharge port 122 from the surroundings.

Moreover, in the first embodiment and the second embodiment, the heat retaining gas injection port 136 is located outside the stretched gas injection port 144 when viewed in the discharge direction of the molten resin MR from the discharge port 122. Since the heat-retaining gas HA surrounds not only the molten resin MR but also the stretched gas EA, not only the molten resin MR but also the stretched gas EA can be kept warm.

Further, the stretched gas injection port 144 is located inside the heat retaining gas injection port 136 when viewed in the discharge direction. Since the stretched gas EA is injected at a position closer to the molten resin MR than the heat retaining gas HA, the effect of bringing the stretched gas EA into contact with the molten resin MR to stretch the molten resin MR is highly exhibited.

Next, the nanofiber manufacturing apparatus of the third embodiment will be described. In the third embodiment, the same elements, members, and the like as in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, since the filter manufacturing apparatus provided with the nanofiber manufacturing apparatus of the third embodiment has the same structure as that of the first embodiment, the illustration is omitted.

The nanofiber manufacturing apparatus 312 of the third embodiment has a discharge unit 314 as shown in FIG. The discharge unit 314 has a long block 316 whose longitudinal direction is the direction of arrow L1 in FIG.

A resin supply pipe 120 is connected to the block 316, and the molten resin MR is supplied from a resin supply member (not shown).

A resin supply path 318 communicating with the resin supply pipe 120 is formed in the block 316 along the longitudinal direction, and a plurality of resin discharge nozzles 118 are provided in the longitudinal direction of the block 316 (arrow L1 direction) at regular intervals. Has been done. As shown in FIG. 13, the molten resin MR is discharged downward from the discharge port 122 at the lower end through the resin flow path 124 of the resin discharge nozzle 118. The resin flow path 124 is a linear hollow portion that goes downward in the resin discharge nozzle 118.

In the third embodiment, the block 316 has a structure divided into two portions in the width direction (arrow W1 direction). In the example shown in FIG. 12, the block 316 has three blocks, a right block 316R on the right side in the width direction and a left block 316L on the left side in the width direction. The resin discharge nozzle 118 extends downward from the right block 316R.

The left block 316L is formed with a through hole 316G penetrating in the thickness direction. The left block 316L is provided with a gas injection member 320 at a position separated from the resin discharge nozzle 118 in the width direction (arrow W1 direction). The gas injection member 320 has an inner tubular member 322 and an outer tubular member 324.

The inner tubular member 322 is concentric with the through hole 316G and fixed to the left block 316L.

The inner tubular member 322 has an inner cylindrical portion 322A formed in a cylindrical shape and an inner truncated cone portion 322B extending from the inner cylindrical portion 322A. The inner portion of the through hole 316G and the inner tubular member 322 is a high-speed high-temperature air nozzle 138 that injects high-speed high-temperature air as a stretched gas EA.

The inner truncated cone portion 322B has a tapered shape that is inclined in a truncated cone shape from the inner cylindrical portion 322A toward the injection direction of the stretched gas EA (direction of arrow T2). Therefore, the high-speed high-temperature air nozzle 138 of the third embodiment has a shape in which the nozzle diameter gradually decreases (is gradually narrowed down) toward the injection direction of the stretched gas EA.

The outer tubular member 324 is oriented one-to-one with the inner tubular member 322 and is fixed at the same core as the inner tubular member 322. The outer tubular member 324 has an outer cylindrical portion 324A surrounding the inner cylindrical portion 322A and an outer truncated cone portion 324B surrounding the inner truncated cone portion 322B.

A gap GP-4 is formed between the outer circumference of the inner tubular member 322 and the inner circumference of the outer tubular member 324, and the gap GP-4 is the gap GP-4 in the third embodiment. Is a heated steam nozzle 146.

The outer cylindrical portion 324A is formed in a cylindrical shape. On the other hand, the outer truncated cone portion 324B has a tapered shape that is inclined in a truncated cone shape toward the center line CL-2 of the inner tubular member 322. Therefore, in the third embodiment, the injection direction of the heat-retaining gas HA from the heat-retaining gas injection port 136 is toward the downstream in the flow direction of the stretched gas EA with respect to the stretched gas EA injected from the stretched gas injection port 144. Therefore, it approaches.

In the third embodiment, the gas injection member 320 that also serves as the high-speed high-temperature air nozzle 138 and the heated steam nozzle 146 is an example of the nozzle that also serves as an injection port in the present application.

The gas injection member 320 is inclined in a direction toward the molten resin MR at a predetermined inclination angle θ with respect to the resin discharge direction from the resin discharge nozzle 118.

Further, also in the third embodiment, the downstream end 322C of the inner tubular member 322 and the downstream end 324C of the outer tubular member 324 are the same in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122. In position. Therefore, the relationship between the stretched gas injection port 144 and the heat retaining gas injection port 136 is also at the same position in the discharge direction of the molten resin MR from the discharge port 122.

In order to manufacture nanofibers by the nanofiber manufacturing apparatus 312 of the third embodiment having such a configuration, first, as shown in FIG. 13, the molten resin MR is discharged from the discharge port 122. The molten resin MR hangs down toward the downstream side in the discharge direction, that is, toward the lower side.

In this state, as shown in FIG. 14, the heat-retaining gas HA is injected from the heat-retaining gas injection port 136. The heat-retaining gas HA brings the molten resin MR into a state in which its viscosity is lowered. Further, as shown in FIG. 15, the stretched gas EA is injected from the stretched gas injection port 144. The molten resin MR is stretched downstream by the stretched gas EA to form nanofibers. The formed nanofibers are supported on support 88 (see FIG. 2).

Also in the nanofiber manufacturing apparatus 312 of the third embodiment, the stretched gas injection port 144 and the heat retaining gas injection port 136 are located at the same position in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122. .. Since the stretched gas EA and the heat-retaining gas HA come into contact with the molten resin MR substantially at the same time, it is possible to suppress that the influence of the gas previously contacted with the molten resin MR becomes dominant. The effect of effectively stretching the molten resin MR, that is, the effect of thinning the nanofibers is high.

Next, the nanofiber manufacturing apparatus of the fourth embodiment will be described. In the fourth embodiment, the same elements, members, and the like as in the first to third embodiments are designated by the same reference numerals, and detailed description thereof will be omitted. Further, since the filter manufacturing apparatus provided with the nanofiber manufacturing apparatus of the fourth embodiment has the same structure as that of the fourteenth embodiment, the illustration is omitted.

The nanofiber manufacturing apparatus 412 of the fourth embodiment has a discharge unit 414 as shown in FIG. The discharge unit 414 has a long block 416 whose longitudinal direction is the direction of arrow L1 in FIG. A plurality of resin flow paths 124 continuous from the resin supply path 318 are formed in the block 416. In the fourth embodiment, the plurality of resin flow paths 124 form the resin discharge nozzle 118.

The block 418 is provided in contact with the block 416 in the width direction (W1 direction). In the example shown in FIG. 16, the block 418 is divided into an upper block 418U and a lower block 418L.

Through holes 418G and 418H penetrating the upper block 418U and the lower block 418L in the thickness direction are formed. The through hole 418H is concentric with the through hole 418G and has a larger inner diameter than the through hole 418G.

The inner tubular member 322 is housed in the through hole 418H of the lower block 418L. The downstream end 322C of the inner tubular member 322 is at the same position as the lower surface 418C of the lower block 418L. A gap GP-5 is formed between the outer peripheral surface of the inner tubular member 322 and the inner peripheral surface of the through hole 418H, and this gap GP-5 serves as a heated steam nozzle 146. Therefore, in the fourth embodiment, the lower block 418L has a structure that also serves as a plurality of outer tubular members 324. Further, also in the fourth embodiment, the stretched gas injection port 144 and the heat retaining gas injection port 136 are at the same position in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122.

In order to manufacture nanofibers by the nanofiber manufacturing apparatus 412 of the fourth embodiment having such a configuration, as shown in FIG. 17, the discharge port 122 is similar to the nanofiber manufacturing apparatus 312 of the third embodiment. The molten resin MR is discharged from. The molten resin MR hangs down toward the downstream side in the discharge direction, that is, toward the lower side.

Then, as shown in FIG. 18, the heat-retaining gas HA is injected from the heat-retaining gas injection port 136 to bring the molten resin MR into a state in which the viscosity is lowered. Further, as shown in FIG. 19, the stretched gas EA is jetted from the stretched gas injection port 144, and the molten resin MR is stretched downstream to form nanofibers.

Also in the nanofiber manufacturing apparatus 412 of the fourth embodiment, the stretched gas injection port 144 and the heat retaining gas injection port 136 are located at the same position in the discharge direction (arrow T1 direction) of the molten resin MR from the discharge port 122. .. Since the stretched gas EA and the heat-retaining gas HA come into contact with the molten resin MR substantially at the same time, it is possible to suppress that the influence of the gas previously contacted with the molten resin MR becomes dominant. The effect of effectively stretching the molten resin MR, that is, the effect of thinning the nanofibers is high.

In the third embodiment and the fourth embodiment, the high-speed high-temperature air nozzle 138 and the heated steam nozzle 146 are also used as the gas injection member 320. Therefore, the number of parts can be reduced as compared with the configuration in which the high-speed high-temperature air nozzle 138 and the heated steam nozzle 146 are provided as separate members.

Moreover, by integrating the high-speed high-temperature air nozzle 138 and the heated steam nozzle 146, it is possible to easily realize a structure in which the stretched gas injection port 144 and the heat-retaining gas injection port 136 are substantially at the same position. Since the stretched gas injection port 144 and the heat-retaining gas injection port 136 are at the same position, the stretched gas EA and the heat-retaining gas HA come into contact with the molten resin MR at the same position. Therefore, as compared with the structure in which the stretched gas EA and the heat-retaining gas HA are in contact with the molten resin MR at different positions, it is possible to suppress the influence of either the stretched gas EA or the heat-retaining gas HA on the stretched gas EA. ..

In the third embodiment and the fourth embodiment, the gas injection member 320 is inclined in the direction toward the molten resin MR at a predetermined inclination angle θ with respect to the resin discharge direction from the resin discharge nozzle 118. That is, the injection direction of the stretched gas EA from the stretched gas injection port 144 (direction of arrow T2) is inclined so as to be asymptotic to the molten resin MR discharged from the discharge port 122. Therefore, for example, as compared with the configuration in which the injection direction of the stretched gas EA is orthogonal to the discharge direction of the molten resin MR from the discharge port 122, the effect of stretching the molten resin MR to obtain finer nanofibers is obtained. high.

Further, the injection direction of the heat insulating gas HA from the heat insulating gas injection port 136 (direction of arrow T2) is also inclined so as to be asymptotic to the molten resin MR discharged from the discharge port 122. Therefore, for example, the heat-retaining gas HA can also keep the molten resin MR warm over a wide range as compared with the configuration in which the injection direction is orthogonal to the discharge direction of the molten resin MR from the discharge port 122.

In each of the first and second embodiments, as shown in FIG. 3, the heat insulating gas injection port 136 is an annular shape continuous in the circumferential direction when viewed in the direction of arrow IV (see FIG. 1). Further, as shown in FIG. 4, the stretched gas injection port 144 is also an annular shape continuous in the circumferential direction when viewed in the direction of arrow IV (see FIG. 1). As a result, the heat-retaining gas HA and the stretched gas EA can be uniformly injected in the circumferential direction. However, the heat retaining gas injection port 136 and the stretched gas injection port 144 do not have to be continuous in the circumferential direction. For example, as shown in FIG. 20 as a modification of the first embodiment, the stretched gas injection port 144 is composed of divided injection holes 144D divided into a plurality of (four in the example shown in FIG. 20) in the circumferential direction. You may. Similarly, the heat retaining gas injection port 136 may also be composed of the divided injection holes 136D divided into a plurality of parts in the circumferential direction.

Further, as shown in FIG. 21, the stretched gas injection port 144 may have a structure in which small pore-shaped injection pores 144H are arranged side by side at regular intervals in the circumferential direction. Similarly, the heat retaining gas injection port 136 may also be composed of small pore-shaped injection pores 136H arranged side by side at regular intervals in the circumferential direction.

In each of the above embodiments, as the heat-retaining gas HA, air that has been heated to a predetermined temperature range by heating the atmosphere can be used, but further, this air is humidified to a predetermined humidity range. It is possible to use air. When the heat-retaining gas HA is within a predetermined humidity range, careless bonding and entanglement can be suppressed when the molten resin MR discharged from the discharge port 122 becomes fine fibrous nanofibers. In particular, in each of the above embodiments, heated steam is used as the heat-retaining gas HA. The effect of suppressing the bonding, curling, and entanglement of the fibers in a state where the molten resin MR hangs down and becomes fibrous due to water vapor that becomes higher humidity than the atmosphere is more effective than when the atmosphere is used as a heat insulating gas. high.

112 Nanofiber manufacturing equipment 114 Discharge unit 118 Resin discharge nozzle 118C Downstream end 120 Resin supply pipe 122 Discharge port 124 Resin flow path 126 Air nozzle 128 First tubular member 128C Downstream end 130 Second tubular member 130C Downstream end 132 Third Cylindrical member 132C Downstream end 136 Thermal insulation gas injection port 136D Split injection hole 136H Injection pore 138 High-speed high-temperature air nozzle 140 High-speed high-temperature air supply pipe 144 Stretched gas injection port 146 Heated steam nozzle 212 Nanofiber manufacturing equipment 214 Discharge unit 312 Nanofiber Manufacturing equipment 320 Gas injection member 412 Nanofiber manufacturing equipment 414 Discharge unit

Claims (6)

A resin discharge member that discharges molten resin from the discharge port,
A heat-retaining gas injection member that injects a heat-retaining gas having a temperature higher than the atmosphere toward the molten resin discharged from the discharge port from the heat-retaining gas injection port.
A stretched gas injection member that injects a stretched gas having a temperature higher than the atmosphere from a stretched gas injection port at the same position as the heat retaining gas injection port toward the molten resin in the discharge direction of the molten resin.
Nanofiber manufacturing equipment with. The nanofiber manufacturing apparatus according to claim 1, wherein the heat-retaining gas injection port and the stretched gas injection port surround the discharge port when viewed in the discharge direction of the molten resin from the discharge port, respectively. The nanofiber manufacturing apparatus according to claim 2, wherein the heat-retaining gas injection port is located outside the stretched gas injection port when viewed along the discharge direction. The nanofiber manufacturing apparatus according to claim 1, further comprising a nozzle that also serves as an injection port and includes the heat-retaining gas injection port and the stretched gas injection port. The nanofiber according to any one of claims 1 to 4, wherein the injection direction of the stretched gas from the stretched gas injection port is inclined so as to be asymptotic to the molten resin discharged from the discharge port. manufacturing device. The nanofiber according to any one of claims 1 to 5, wherein the injection direction of the heat-retaining gas from the heat-retaining gas injection port is inclined so as to be asymptotic to the molten resin discharged from the discharge port. manufacturing device.

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