WO2019187887A1

WO2019187887A1 - Stretching device as well as manufacturing device and manufacturing method for fiber and fiber web

Info

Publication number: WO2019187887A1
Application number: PCT/JP2019/007201
Authority: WO
Inventors: 田村知樹; 山本拓; 箭内勝文
Original assignee: 東レ株式会社
Priority date: 2018-03-29
Filing date: 2019-02-26
Publication date: 2019-10-03
Also published as: KR102391138B1; JPWO2019187887A1; CN111868312B; CN111868312A; KR20200138204A; JP6965922B2

Abstract

In order to provide a stretching device that is capable of efficiently applying a traction force to yarns, thus making it possible to stably manufacture fine yarns while saving energy, the present invention provides a stretching device that stretches a yarn obtained by subjecting a thermoplastic polymer to melt spinning and blowing air onto the yarn inwardly from outside a transfer path of the yarn in a channel having an inlet and an outlet for the yarn, the stretching device being characterized in that the channel having the inlet and the outlet for the yarn is provided with a first airflow channel, an airflow jetting hole, a second airflow channel, a third airflow channel, and a fourth airflow channel, continuously in this order along the yarn transfer direction, and in that the following (i) to (iv) are satisfied. (i) The third airflow channel has a fixed flow channel sectional area along the yarn transfer direction. (ii) The second airflow channel has a smaller flow channel sectional area than the third airflow channel, and the flow channel sectional area thereof is fixed and/or gradually increases along the yarn transfer direction. (iii) The fourth airflow channel has a greater flow channel sectional area than the third airflow channel, and the flow channel sectional area thereof is constant and/or gradually increases along the yarn transfer direction. (iv) The length L₂ of the second airflow channel in the yarn transfer direction, the length L₃ of the third airflow channel in the yarn transfer direction, and the length L₄ of the fourth airflow channel in the yarn transfer direction satisfy the following relationships: (L₃ + L₄) / (L₂ + L₃ + L₄) ≥ 0.6 and L₄ / (L₂ + L₃ + L₄) ≤ 0.4.

Description

Stretching apparatus, and fiber and fiber web manufacturing apparatus and manufacturing method

The present invention relates to a stretching apparatus, and a fiber and fiber web manufacturing apparatus and manufacturing method using the stretching apparatus.

Conventionally, in the production of nonwoven fabrics, various researches and developments have been made on a method of stretching a thermoplastic polymer discharged from a spinneret into a thread shape, and it has been implemented in several apparatus structures. Generally, in the traveling path of a yarn discharged from a spinneret having a spinning hole, a high-speed gas is supplied from the upstream side to the downstream side of the yarn to impart tension to the yarn, thereby finely tying the yarn. There is a stretching device to make it. The nonwoven fabric is continuously produced by fixing the yarn discharged from the drawing device to the collector.

More specifically, for example, Patent Document 1 discloses an open drawing apparatus. In Patent Document 1, gas is blown out into a passage in which an inlet for sucking a yarn group pushed out from a spinneret and an outlet for discharging a yarn group sucked from the inlet are formed, and a gas flow in a suction direction is formed. And a stretching device provided with a divergent portion in which the passage width on the outlet side is wider than the passage width on the inlet side between the gas injection port and the outlet of the passage. Has been. Using this device, the velocity of the mixed flow of the gas flow (primary gas flow) generated by being supplied from the injection port to the passage and the gas flow (secondary gas flow) generated by being sucked into the passage from the inlet of the passage The amount of decrease is reduced and the yarn swing in the passage is suppressed, and the secondary gas flow rate is increased, so even if the primary gas flow rate is the same, the spinning tension and spinning of the yarn group are the same. Speed can be increased and energy efficiency can be increased.

Further, Patent Document 2 discloses a stretching apparatus in which the space from the spinneret to the cooling chamber and the stretching apparatus is a closed system. In Patent Document 2, the connection between the cooling chamber and the stretching device is closed with respect to the surroundings (a closed system in which air does not flow in and out), and at least one diffuser (flow passage restriction) is provided downstream of the stretching device. It has been proposed to provide widening. When this drawing apparatus is used, the spinning speed of the filament can be increased and a thinner filament can be obtained.

JP 2002-371428 A Japanese Patent No. 3704522

However, in the stretching apparatus of Patent Document 1, from the viewpoint of reducing the resistance of the air flow in the stretching apparatus passage and the loss caused thereby, a region having a constant passage width between the gas injection port and the divergent portion is set to 1 to 10 of the passage width. It is preferably provided in the range of double (path length in the embodiment: 3 to 30 mm). That is, the idea of shortening the passage length (hereinafter referred to as a passage x) in a region having a constant passage width and increasing the passage length (hereinafter referred to as a passage y) at the divergent portion is disclosed. However, in such a configuration in which the passage x is short and the passage y is long, sufficient traction force for stretching the yarn group cannot be obtained, and the spinning tension and spinning speed of the yarn group may be reduced. is there. Furthermore, in the example of Patent Document 1, the entire length of the drawing device in the yarn traveling direction is 100 mm, and the section for applying tension to the yarn is short, and the traction force is proportional to the passage length. It may be insufficient to obtain a spinning tension for drawing the yarn group and producing a fine filament.

Further, in the stretching apparatus of Patent Document 2, since the diaphragm is used and the throttle is provided in the middle of the flow path, the pressure loss increases in the throttle part, and sufficient gas cannot be supplied. Therefore, the high wind speed condition cannot be obtained, and it may be difficult to manufacture a fine filament. Furthermore, in the apparatus of Patent Document 2, the cooling chamber and the stretching apparatus become a closed system, and the filament is stretched in the stretching apparatus using the airflow supplied from the cooling chamber. There are restrictions on the amount of airflow that can be supplied, which may result in insufficient cooling of the filament. In addition, when a yarn is manufactured for a long time, filaments may accumulate on the narrowed portion, resulting in unevenness of the sheet.

Therefore, an object of the present invention is to provide a drawing device capable of efficiently producing a pulling force on a yarn and capable of producing a yarn having a fineness with energy saving and stably. Another object of the present invention is to provide a fiber and fiber web manufacturing apparatus and method using such a stretching apparatus.

In order to achieve the above object, the present invention has any one of the following configurations.
(1) In a passage having an inlet and an outlet for a yarn obtained by melt spinning a thermoplastic polymer, an air stream is blown inward from the outside of the running path of the yarn to stretch the yarn. In the drawing apparatus, the passage having the inlet and the outlet of the yarn includes the first airflow passage, the airflow injection port, the second airflow passage, the third airflow passage, and the fourth airflow passage with respect to the yarn traveling direction. A stretching apparatus which is continuously provided in this order and satisfies the following (i) to (iv):
(I) The third airflow passage has a constant flow path cross-sectional area with respect to the yarn traveling direction.
(Ii) The second airflow passage has a flow passage cross-sectional area smaller than that of the third airflow passage, and the flow passage cross-sectional area is constant and / or gradually increased with respect to the yarn traveling direction.
(Iii) The fourth airflow passage has a flow passage cross-sectional area larger than that of the third airflow passage, and the flow passage cross-sectional area is constant and / or gradually increased with respect to the yarn traveling direction.
(Iv) the length L ₂ of the yarn running direction of the second air flow passage, the length of the third and the yarn running direction of the length L ₃ of the air flow passage, the yarn running direction of the fourth air flow path L ₄ satisfies the following relational expression.
(L ₃ + L ₄ ) / (L ₂ + L ₃ + L ₄ ) ≧ 0.6
L ₄ / (L ₂ + L ₃ + L ₄ ) ≦ 0.4
(2) the sum of the _{L 2} and the _{L 3} and the _{L 4} (mm) satisfies the following relationship, stretching apparatus according to (1).
L ₂ + L ₃ + L ₄ ≧ 100
(3) The minimum flow path cross-sectional area H _{2MIN of} the second air flow path, the flow path cross-sectional area H _{3 of} the third air flow path, and the maximum flow cross-sectional area H _{4MAX of} the fourth air flow path are as follows: The stretching apparatus according to (1) or (2), which satisfies the formula.
1.05 ≦ H ₃ / H _2MIN
1.05 ≦ H _4MAX / H ₃
(4) The passage having the yarn inlet and outlet is formed by a pair of opposed outer wall members, and one passage forming surface of the pair of outer wall members is separated from the second airflow passage in the yarn traveling direction. The stretching apparatus according to any one of (1) to (3), wherein a space between the fourth airflow path and the fourth airflow path is formed as a continuous single plane parallel to the yarn traveling direction.
(5) A fiber manufacturing apparatus having a spinneret, a cooling device for spun yarn, and a drawing device according to any one of (1) to (4) in the yarn traveling direction in this order. .
(6) A spinneret, a cooling device for the spun yarn, a drawing device according to any one of (1) to (4), and a fiber web conveyor provided with a net, in the yarn running direction In this order, the fiber web manufacturing apparatus.
(7) A yarn is formed by melt spinning a thermoplastic polymer from a spinneret, and the yarn is cooled and solidified, and then the yarn is stretched by the drawing apparatus according to any one of (1) to (4). A method for producing a fiber.
(8) A method for producing a fiber web, wherein a fiber web is produced using the apparatus according to any one of (1) to (6).

Here, in the present invention, the “passage” refers to an airflow passage formed by an outer wall member that surrounds the outer side of the yarn travel path and having an inflow port and an outflow port that are open to the outside, in the following order: It is comprised by the continuous 1st airflow path, the airflow injection port, the 2nd airflow path, the 3rd airflow path, and the 4th airflow path.

In the present invention, the “inlet” refers to an opening that is disposed on the most upstream side in the yarn traveling direction of the passage and is open to the outside. On the other hand, the “outlet” refers to an opening that is disposed on the most downstream side in the yarn traveling direction of the passage and is open to the outside. The term “upstream” refers to a side closer to the spinneret in the main yarn traveling direction in which the thermoplastic polymer discharged from the spinneret is solidified by cooling and becomes a yarn. On the other hand, the “downstream” means a side farther from the spinneret in the traveling direction of the main yarn that becomes a yarn by cooling and solidifying the thermoplastic polymer discharged from the spinneret.

In the present invention, the “air flow injection port” refers to an opening provided in the passage and through which gas is injected.

In the present invention, the “first airflow passage” means a portion from the inlet to the upstream end of the airflow injection port in the passage, and the “second airflow passage” means an airflow in the passage. This refers to the interval from the downstream end of the injection port to the upstream end of the third airflow passage. In addition, the “third airflow passage” refers to a portion of the passage that exists between the second airflow passage and the fourth airflow passage and has a constant cross-sectional area with respect to the yarn traveling direction. The “fourth airflow passage” refers to a portion of the passage from the downstream end of the third airflow passage to the outlet.

In the present invention, the “minimum flow path cross-sectional area H _{2MIN of} the second air flow passage” means a flow break at a position in the second air flow passage where the cross-sectional area in the direction perpendicular to the running direction of the yarn is minimum. It refers to the area. In addition, the “maximum flow path cross-sectional area H _{4MAX of} the fourth airflow path” means a flow path cross-sectional area at a position where the cross-sectional area in the direction perpendicular to the running direction of the yarn is maximum in the fourth airflow path. Say. The “flow passage cross-sectional area H _{3 of} the third airflow passage” refers to a flow passage cross-sectional area of the third airflow passage in a direction perpendicular to the yarn traveling direction.

According to the drawing device of the present invention, by relatively elongating the section where the pulling force can be applied to the yarn, the yarn pulling effect in the drawing device is sufficiently expressed even if the gas supply amount is small. As a result, stable operation with energy saving becomes possible. Further, since the traction force can be sufficiently expressed, the spinning speed can be improved, and a yarn having a small single yarn fineness can be obtained. And when manufacturing a fiber web from the fiber obtained by doing in this way, it becomes possible to obtain the fiber web with a favorable texture with the reduction | decrease of single yarn fineness.

1 is an overall schematic cross-sectional view of a spinning device including a stretching device according to an embodiment of the present invention. It is a schematic sectional drawing of the extending | stretching apparatus which shows one Embodiment of this invention. It is a schematic sectional drawing of an extending | stretching apparatus another embodiment of this invention. It is a schematic sectional drawing of the extending | stretching apparatus which shows another embodiment of this invention. It is the value which measured the static pressure distribution in a channel | path in the extending | stretching apparatus concerning embodiment of this invention and a prior art. It is a schematic cross section for demonstrating the measuring method of the tractive force of an extending | stretching apparatus. It is a perspective view for demonstrating the measuring method of the static pressure in the channel | path of an extending | stretching apparatus. It is a schematic sectional drawing of the extending | stretching apparatus which shows another embodiment of this invention.

Hereinafter, the best embodiment of the stretching apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall schematic longitudinal sectional view of a spinning device provided with a stretching apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic longitudinal sectional view of the stretching apparatus used in FIG. Moreover, FIG.3, FIG.4, FIG.8 is a schematic longitudinal cross-sectional view of the other preferable form of the extending | stretching apparatus concerning this invention.

The stretching apparatus of the present invention is used in, for example, a nonwoven fabric manufacturing apparatus, which, as shown in FIG. 1, captures fibers in a web shape on a spinneret 1, a cooling device 19, a stretching apparatus 3, and a moving net. Consists of a conveyor 4 and the like to collect. Although not shown, a mechanism for thermally bonding the fiber web is also provided on the downstream side of the conveyor 4.

In such an apparatus, a thermoplastic polymer is melt-spun from the spinneret 1, and the obtained yarn 2 is cooled by the cooling device 19 and then stretched by the stretching device 3 with tension applied. The yarn 2 is then sprayed from the stretching device 3 onto the net of the conveyor 4 to form a fiber web on the conveyor 4. Here, as a region where the yarn travels in the stretching device 3, a long rectangular region that is very long in the machine width direction (the depth direction of the drawing in FIG. 1) is formed.

As shown in FIG. 2, the stretching device 3 has an airflow passage 9 that is sandwiched between outer wall members 5 from the upstream side to the downstream side in the yarn traveling direction, and an upstream end portion of the airflow passage 9. Has an inlet 14 through which the yarn flows in, and an outlet 15 through which the yarn flows out at the downstream end. The airflow passage 9 includes a first airflow passage 10 located downstream of the inflow port 14 in the yarn traveling direction, an airflow injection port 7 that communicates with the first airflow passage 10 and blows an airflow onto the yarn, and an airflow injection port. 7, the second airflow passage 11 located downstream in the yarn running direction, the third airflow passage 12 located downstream in the yarn running direction of the second airflow passage 11, and the downstream side of the third airflow passage 12. And the fourth airflow passage 13 located at the center. The third airflow passage 12 has a constant flow path cross-sectional area in a direction perpendicular to the yarn traveling direction with respect to the yarn traveling direction, and the second airflow passage 11 is more in the yarn traveling direction than the third airflow passage 12. The fourth airflow passage 13 includes a part of the outlet 15 through which the yarn flows out, and is perpendicular to the yarn traveling direction as compared with the third airflow passage 12. The channel cross-sectional area of is large.

In the stretching apparatus 3 having the above-described configuration, the gas introduced into the buffer unit 6 of the airflow supply means is then injected into the airflow passage 9 from the airflow injection port 7 through the gas supply pipe. Then, it passes through the second airflow passage 11, the third airflow passage 12, and the fourth airflow passage 13 and is discharged from the outlet 15 to the outside. According to the flow of the airflow, the yarn that flows in along with the airflow from the inlet 14 passes through the inside of the airflow passage 9 and is discharged from the outlet 15.

Here, in the drawing apparatus 3 of the present invention, the principle that the yarn pulling effect is sufficiently exhibited, the gas supply amount can be reduced, and the energy can be saved will be described. The stretching device 3 is generally called an ejector, and pulls and stretches the yarn by supplying a high-pressure compressed gas directly to the airflow passage 9. At that time, since compressed gas is used, a compressor is separately required, and accordingly, equipment costs are required, and utility costs are increased, leading to an increase in manufacturing costs. Therefore, in order to reduce the amount of compressed gas used, it is important to most effectively express the yarn pulling force in the drawing device 3, but the drawing force applied to the yarn by the drawing device is F, a constant. Is CF, the density of the air current is ρ, the air speed of the air current is w, the circumferential length of the yarn is c, and the length of the air current passage is l, the traction force F is the air speed of the air current as shown in the equation (A). It is proportional to the square of w and the length l of the airflow passage.
F = CFρw ² cl (A)
Therefore, as a method of increasing the traction force F, it is conceivable to increase the wind speed w of the gas passing through the airflow passage 9 as much as possible. However, it is expected that the gas wind speed w increases by narrowing the gap of the airflow passage 9 (that is, when the flow path cross-sectional area is reduced). The amount of gas flowing in from 14 is reduced. As a result, it has been found that there is a limit to narrowing the gap of the airflow passage 9 (that is, reducing the cross-sectional area of the flow path). Next, increasing the amount of gas supplied from the airflow injection port 7 is also considered to be an effective means for increasing the wind speed w of the gas, but naturally the amount of compressed air used is increased. This leads to an increase in manufacturing cost.

Therefore, as a result of intensive studies for solving the above problems, the present inventors have focused on the length and gap of the airflow passage 9. The present inventors have found that by optimizing these, the amount of gas flowing in from the inlet 14 can be increased, and as a result, the traction force F of the yarn in the drawing device 3 can be increased. The important point is the configuration of the second airflow passage 11, the third airflow passage 12, and the fourth airflow passage 13 from the downstream end 8 of the airflow injection port to the outlet 15. increasing the length L ₃ of the constant is the third airflow passage 12 with respect to the cross-sectional area of the yarn running direction, while the length of the second air flow passage 11 having a smaller cross sectional area than the flow path cross-sectional area of the third airflow passageway L _2, and is that to shorten the length L ₄ of the fourth air flow passage 13 having a sectional area larger than the flow path cross-sectional area of the third airflow passageway 12.

Specifically, the following relationship is satisfied.
(I) The third airflow passage 12 has a constant cross-sectional area with respect to the yarn traveling direction.
(Ii) The second airflow passage 11 has a flow passage cross-sectional area smaller than that of the third airflow passage 12, and the flow passage cross-sectional area is constant and / or gradually increased with respect to the yarn traveling direction.
(Iii) The fourth air flow passage 13 has a flow passage cross-sectional area larger than that of the third air flow passage 12, and the flow passage cross-sectional area is constant and / or gradually increased with respect to the yarn traveling direction.
(Iv) the yarn to the running direction of the length L _2, the length of the third and the yarn running direction of the length L ₃ of the air flow passage 12, the yarn running direction of the fourth air flow path 13 of the second air flow passage 11 L ₄ satisfies the following relational expression.
(L ₃ + L ₄ ) / (L ₂ + L ₃ + L ₄ ) ≧ 0.6
L ₄ / (L ₂ + L ₃ + L ₄ ) ≦ 0.4
First, by adopting the configurations of (ii) and (iii), the diffuser effect is manifested in the second airflow passage 11 and the fourth airflow passage 13, and gas easily travels through the airflow passage 9, as shown in FIG. Since the static pressure in the airflow passage 9 decreases, a pressure difference from the outside is generated, and the amount of gas flowing in from the inlet 14 increases. Since the supply gas supplied from the airflow injection port 8 is combined with the inflowing gas and supplied to the second airflow passage 11, the wind speed w of the gas in the second airflow passage 11 and the third airflow passage 12 increases. To do.

And by having the configuration of (i) and (iv), the length of the third airflow passage 12 in the yarn traveling direction can be increased while maintaining the state where the static pressure in the airflow passage 9 is lowered. It becomes possible to maintain the high wind speed level of the airflow in the third airflow passage 12 for a long time. As a result, the yarn pulling force F can be effectively expressed.

Here, when the cross-sectional area of the flow path is larger in the second airflow path 11 than the third airflow path 12, or smaller in the fourth airflow path than the third airflow path, the static pressure in the gas path 9 increases. Therefore, the pressure difference with the outside becomes small, and the inflow amount of gas flowing in from the inflow port 14 decreases. In the worst case, the airflow passage 9 has a higher pressure than the outside, and gas may flow out from the inlet 14. As a result, the wind speed w of the gas in the third airflow passage 12 decreases, and the yarn pulling force cannot be obtained.

When (L ₃ + L ₄ ) / (L ₂ + L ₃ + L ₄ ) is smaller than 0.6, the second air flow passage having a small flow passage cross-sectional area becomes long, and thus the static pressure in the air flow passage 9 is reduced. Since it increases, the pressure difference with the outside becomes small, and the inflow amount of gas flowing in from the inlet 14 decreases. In addition, when L ₄ / (L ₂ + L ₃ + L ₄ ) exceeds 0.4, the fourth airflow passage 13 in which the wind speed decreases is lengthened, so that a section in which the traction force with respect to the yarn is decreased is lengthened. The traction force of the yarn cannot be obtained sufficiently.

In addition, (L ₃ + L ₄ ) / (L ₂ + L ₃ + L ₄ ) sufficiently secures a section in which the traction force with respect to the yarn is large (that is, the second airflow passage 11 having a high wind speed) and sufficiently exerts the traction force on the yarn. Therefore, it is preferably 0.99 or less. In addition, L ₄ / (L ₂ + L ₃ + L ₄ ) is sufficient to sufficiently secure the section of the fourth airflow passage 13 and stabilize the flow in the fourth airflow passage 13 to sufficiently exhibit the diffuser effect. Moreover, it is preferable that it is 0.01 or more.

The second air flow passage 11 and the fourth air flow passage 13 each have a constant flow path cross-sectional area toward the downstream side in the yarn running direction in FIG. 2, but as shown in FIG. You may increase gradually as it goes to the downstream of a direction. In this case, the diffuser effect is easily exhibited in the second air flow passage 11 and the fourth air flow passage 13, and the static pressure in the air flow passage 9 is further reduced, so that the inflow amount of gas flowing in from the inflow port 14 is increased. Has advantages. In FIG. 3, the taper is gradually increased. However, the present invention is not limited to this, and the taper may be gradually increased. Moreover, in FIG. 3, although it may increase gradually over the full length of the 2nd airflow path 11 and the 4th airflow path 13, only one part may increase gradually in a taper shape as shown in FIG.

Furthermore, in the communicating portion between the second airflow passage 11 and the third airflow passage 12 and the communicating portion between the third airflow passage 12 and the fourth airflow passage 13, the flow passage sectional area on the downstream side in the yarn traveling direction. However, as shown in FIG. 2, the cross-sectional area of the flow path may be expanded at a stretch as shown in FIG. 2, or the second airflow passage may be configured as shown in FIGS. 11 and the fourth airflow passage 13 may be configured such that at least the vicinity of the communicating portion with the third airflow passage 12 is tapered so that the cross-sectional area of the flow path gradually increases. Moreover, the structure in which these were combined may be sufficient. Forming the outer wall member 5 so that the cross-sectional area of the flow path is expanded at a stretch only at the communication portion has an advantage that it is easy to process in manufacturing the outer wall member 5, and is tapered in the vicinity of the communication portion. When the outer wall member 5 is formed as described above, the turbulent vortex is less likely to be generated when the gas passes, and the yarn disturbance can be suppressed.

Next, the influence of the length of the second airflow passage 11, the third airflow passage 12, and the fourth airflow passage 13 in the yarn traveling direction on the traction force will be described in detail. In stretching apparatus 3 of the present invention, the length of the yarn running direction of the second air flow passage 11 L ₂ and the yarn running direction of the length L ₃ of the third airflow passageway 12 yarn running direction of the fourth air flow passage 13 it is preferable that the sum of the length L ₄ of the (mm) satisfies the following relation.
L ₂ + L ₃ + L ₄ ≧ 100
With this configuration, the above-described yarn pulling force can be effectively generated. When the above sum is less than 100 mm, the total length of the second airflow passage 11, the third airflow passage 12, and the fourth airflow passage 13 is shortened, so that the length for pulling the yarn is shortened and a desired traction force is obtained. It becomes difficult. Further, since the distance between the outlet 15 and the airflow injection port 7 is close, the pressure loss in the airflow passage is reduced, and it becomes difficult to sufficiently obtain the diffuser effect by using the fourth airflow passage 13. Therefore, it is preferable that the configuration satisfies the above relational expression, and that the sum is 250 or more.

In addition, although the length which pulls a thread | yarn becomes long because the full length of the 2nd airflow path 11, the 3rd airflow path 12, and the 4th airflow path 13 becomes long, the static pressure in the gas path 9 increases. Therefore, the pressure difference with the outside is reduced, and the amount of gas flowing in from the inlet 14 is reduced. Therefore, the total length of the second airflow passage 11, the third airflow passage 12, and the fourth airflow passage 13 is preferably 1500 mm or less, and more preferably 1000 mm or less.

Further, in the present invention, the minimum flow path cross-sectional area _{H 2MIN} of the second air flow passage 11, the flow path cross-sectional area _{H 3} of the third airflow passageway 12 and the maximum flow path cross-sectional area _{H 4MAX} fourth airflow passage 13 It is preferable that the following relational expression is satisfied.
1.05 ≦ H ₃ / H _2MIN
1.05 ≦ H _4MAX / H ₃
With this configuration, the above-described yarn pulling force can be generated more effectively. Here, when the ratio of the cross-sectional area of each flow path is less than 1.05, the flow path is not sufficiently enlarged toward the downstream side in the yarn traveling direction when viewed as the entire airflow passage. In addition, it is difficult to obtain a sufficient diffuser effect in the airflow passage. In order to prevent turbulence in the flow and to exhibit the diffuser effect more effectively, the ratio of the respective channel cross-sectional areas is preferably 3 or less.

Furthermore, in the present invention, one passage forming surface of the pair of outer wall members 5 forming the air flow passage is in the running yarn direction between the second air flow passage 11 and the fourth air flow passage 13 as shown in FIG. It is preferable that it is formed in one continuous plane parallel to the running yarn direction so that the distance from the yarn is constant. With this configuration, a portion where the flow path does not expand is continuously formed on one side of the yarn in the second air flow passage 11 to the fourth air flow passage 13, and as a result, in the vicinity of the portion. An air flow with less turbulence is continuously formed, and it becomes possible to express traction force to the yarn more efficiently.

Next, each member and the shape of each member common to the stretching apparatus 3 of the embodiment of the present invention shown in FIGS. 1, 2, 3, 4, and 8 will be described in detail.

In the stretching apparatus 3 according to the present invention, various materials such as metals, alloys, ceramics, and resins can be employed as the material of the outer wall member 5. Among these, metals are preferable from the viewpoints of strength and wear resistance.

As the cross-sectional shape of the airflow passage 9 in the direction perpendicular to the yarn running direction, various shapes such as a round shape and a rectangular shape can be adopted. Among these, a rectangular shape is preferable from the viewpoint that the amount of compressed air used is relatively small and the yarns are not easily fused or scratched.

Since the length of the first airflow passage 10 in the yarn traveling direction is shortened, the pressure loss in the flow path is reduced, and the amount of gas flowing in from the inlet 14 is increased. Therefore, the length is 100 mm. It is preferable to make it below, and it is more preferable to make it below 50 mm.

The cross-sectional area of the first airflow passage 10 in the direction perpendicular to the yarn traveling direction can be set within a range in which the yarn can flow. Since the pressure loss in the first airflow passage 10 decreases and the amount of gas flowing in from the inlet 14 increases, the minimum cross-sectional area in the direction perpendicular to the yarn traveling direction of the second airflow passage 11 is reduced. On the other hand, it is preferably wide, and more preferably wider than the maximum cross-sectional area in the direction perpendicular to the yarn running direction of the fourth airflow passage 13.

The gas supply pipe connecting the buffer 6 and the airflow injection port 7 preferably has an angle of 30 ° or less with respect to the airflow passage 9 from the viewpoint of suppressing a decrease in wind speed in the airflow passage 9. More preferably, a decrease in wind speed can be suppressed by setting the angle to 15 ° or less. As the shape of the gas supply pipe, the cross-sectional shape in a direction perpendicular to the air flow direction in the gas supply pipe is preferably rectangular. Such a cross-section may be enlarged as the cross-sectional area is constant with respect to the airflow direction in the gas supply pipe or toward the airflow injection port 7, but the effect of the Laval nozzle that increases the wind speed due to adiabatic expansion in the sonic region is obtained. It is more preferable to enlarge toward the airflow injection port 7 so as to be obtained.

Air is the most economical and preferable airflow supplied to the yarn from the airflow injection port 7, but may be mixed gas, steam, saturated steam, or heated steam. In order to improve the traction force of the yarn, it is preferable to select an air stream having a high density because the density ρ of the air stream is also related as in the above formula (A). The temperature of the air flow is most economically preferable at normal temperature, but is not limited thereto. In addition, it is economically preferable that the humidity of the airflow is not controlled because the air is taken in. However, this is not the case. For example, by using a high-humidity airflow, the traction force of the yarn is improved. It becomes possible to make it.

The present invention is an extremely versatile invention and can be applied to the production of all known fiber webs. Therefore, it is not particularly limited by the polymer constituting the fiber web. For example, examples of polymers constituting the fiber web include polyester, polyamide, polyphenylene sulfide, polyolefin, polyethylene, polypropylene, and the like. Further, in the above-mentioned polymers, matting agents such as titanium dioxide, silicon oxide, kaolin, anti-coloring agents, stabilizers, antioxidants, deodorants, flame retardants, yarn friction, as long as the spinning stability is not impaired. Various functional particles such as a reducing agent, a color pigment, and a surface modifier, additives such as organic compounds may be contained, and copolymerization may be included.

Further, the polymer constituting the fiber web may be composed of a single component or a plurality of components. In the case of a plurality of components, examples of the configuration include a core sheath and side-by-side.

The cross-sectional shape of the fibers forming the fiber web may be irregular, such as round, triangular, flat, or hollow. Further, the single yarn fineness of the fiber web is not particularly limited. The number of single yarns of the fiber web is not particularly limited, but the difference from the conventional technology becomes clearer as the number of single yarns of the fiber web increases.

Next, a preferred embodiment for producing a spunbonded nonwoven fabric made of a fibrous web will be specifically described using the apparatus shown in FIGS.

In the apparatus shown in FIG. 1, for example, a polyolefin resin is melt-spun from a spinneret 1. The spinning temperature at this time is preferably 200 to 270 ° C., more preferably 210 to 260 ° C., and further preferably 220 to 250 ° C. By setting the spinning temperature within the above range, a stable molten state can be obtained, and excellent spinning stability can be obtained.

The yarn 2 melt-spun from the spinneret 1 is then cooled by the cooling device 19. As a specific cooling method, for example, a cooling device 19 forcibly blows cold air onto the yarn. , A method of natural cooling at the ambient temperature around the yarn, a method of natural cooling by adjusting the distance between the spinneret 1 and the drawing device 3, and the like. A method combining these methods can also be employed. The cooling conditions can be appropriately adjusted and adopted in consideration of the discharge amount per single hole of the spinneret, the spinning temperature, the atmospheric temperature, and the like.

The yarn cooled by the cooling device 19 is then stretched by being applied with tension by the stretching device 3 as described above, and blown onto the net of the conveyor 4 to form a fiber web on the conveyor 4.

The spinning speed when using the stretching apparatus 3 of the present invention is preferably 3,500 to 6,500 m / min, more preferably 4,000 to 6,500 m / min, and still more preferably 4,500 to 6,500 m / min. 500 to 6,500 m / min. By setting the spinning speed to 3,500 to 6,500 m / min, high productivity can be obtained, and the oriented crystallization of the fibers can proceed to obtain high strength long fibers. For this reason, the nonwoven fabric comprised with a high intensity | strength fiber also becomes the thing excellent in strength.

The stretching apparatus according to the present invention can be used not only for the production of fiber webs but also for the production of fibers used in applications such as clothing and industry. In that case, the fiber obtained by spinning, cooling, and stretching may be wound around a bobbin or the like in the same manner as the above-described nonwoven fabric production.

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, the measuring method of the characteristic value in an Example, etc. are as follows.

(1) Traction force (N):
FIG. 6 shows a schematic diagram of the traction force measurement method. First, a single nylon No. 3 nylon teg (A-154 made by Yutaka Make) 17 is fixed to a tension meter 16 (MODEL-RX-1 made by Aiko Engineering Co., Ltd.), and an air flow passage 9 is formed from the upper part of the drawing device 3. The guts 17 are hung inside, and the guts 17 are cut at the lowest point (outlet 15) of the airflow passage. Then, compressed air was supplied to the stretching device 3, and the tension (N) generated at that time was measured with a tension meter 16. This measurement was repeated 5 times, and the average value (N) was taken as the traction force.

(2) Static pressure (kPa) inside the airflow passage:
As shown in FIG. 7, a stretching device in a state where a pressure gauge (PG-100-102G manufactured by Copal Electronics Co., Ltd.) is hermetically connected to a static pressure measuring port 18 which is a through hole drilled in the side wall member 20 of the airflow passage 9. 3 was supplied with compressed air, and the gauge pressure (kPa) inside the airflow passage 9 was measured. The measurement height was the position of the downstream end 8 of the airflow injection port. This measured value was adopted as the static pressure inside the airflow passage.

(3) Supply pressure (MPa)
In a room of normal temperature and humidity, compressed air is supplied to the stretching device 3 with a pressure gauge (GS50-171-0.6MP, manufactured by Nagano Keiki Co., Ltd.) sealed in the air flow supply section of the stretching device 3. Gauge pressure (MPa) was measured. This measured value was adopted as the supply pressure to the stretching apparatus.

(4) Single fiber fiber diameter (μm):
After pulling with a stretching device and stretching, ten small piece samples were randomly collected from the fiber web collected on the net, and a 1000 times surface photograph was taken with a microscope. The width of a total of 100 fibers, 10 from each sample photograph, was measured, and the average value thereof was adopted as the single fiber fiber diameter.

(5) Spinning speed (m / min):
The mass per 10,000 m in length was calculated as the single fiber fineness from the single fiber fiber diameter and the solid density of the resin to be used, and rounded off to the second decimal place. From the single fiber fineness (dtex) and the discharge amount of resin discharged from the spinneret single hole set under each condition (hereinafter abbreviated as single hole discharge amount) (g / min), based on the following formula: The spinning speed was calculated.
Spinning speed = (10000 × single hole discharge amount) / single fiber fineness.

[Example 1]
A fiber web was manufactured as follows using the apparatus having the configuration shown in FIGS. Incidentally, the stretching device 3, the cross section of the air flow passage 9 is rectangular, the length L from the inlet 14 of the air flow passage 9 to the outlet port 15 200 mm, 50 mm and length _{L 2} of the second air flow passage 11, the 3 50 mm length _{L 3} of the air flow passage 12, the length _{L 4} of the fourth air flow passage 13 was set to 50 mm. Also, the gap _{W 1} of the first air flow passage 3 mm, and the gap _{W 2} of the second air flow passage 3 mm, 4 mm gap _{W 3} of the third airflow passageway, a gap _{W 4} of the fourth

air flow passage

13 and 5 mm. The installation angle of the airflow supply pipe with respect to the airflow passage 9 was 15 °, and the width of the airflow supply pipe was 0.2 mm. In addition, 0.2 MPa compressed air was supplied to the air flow supply unit to the stretching device 3. As a result of measuring the traction force, it was 37 mN as shown in Table 1. In addition, the static pressure in the airflow passage 9 at the downstream end 8 of the airflow injection port was −6.3 kPa.

A polypropylene resin having a melt flow rate (MFR) of 35 g / 10 min was melted by an extruder and spun from a rectangular spinneret 1 with a spinning temperature of 235 ° C. and a hole diameter of 0.30 mm at a single hole discharge rate of 0.56 g / min. After the obtained yarn is cooled and solidified by the cooling device 19, it is pulled and drawn by supplying compressed air having a supply pressure of 0.20 MPa to the drawing device 3, and collected on a moving net to obtain a polypropylene length. A fiber web made of fibers was obtained.

The properties of the obtained polypropylene long fiber were a single fiber diameter of 16.6 μm, and a spinning speed calculated from this was 2,951 m / min.

[Example 2]
As a pattern in which the total length of the second airflow passage 11, the third airflow passage 12, and the fourth airflow passage 13 is long, the length L from the inlet 14 to the outlet 15 of the airflow passage 9 is 350 mm, and the second airflow passage 11 100mm length _{L 2} of the length _{L 3} of 100mm of the third airflow passageway 12, except that the length _{L 4} of the fourth air flow path 13 and 100mm were the same as in example 1.

As a result of measuring the traction force, it was 40 mN as shown in Table 1. The static pressure in the airflow passage 9 at the downstream end 8 on the airflow injection port was −5.5 kPa.

The characteristics of the obtained polypropylene long fiber were a monofilament fiber diameter of 16.1 μm, and a spinning speed calculated from this was 3,043 m / min.

[Example 3]
As a pattern in which the total length of the second airflow passage 11, the third airflow passage 12 and the fourth airflow passage 13 is short, the length L from the inlet 14 to the outlet 15 of the airflow passage 9 is 140 mm, and the second airflow passage 11. length _{L 2} to 30mm, length _{L 3} of the 30mm of the third airflow passageway 12, except that the length _{L 4} of the fourth air flow path 13 and 30mm were the same as in example 1.

As a result of measuring the traction force, it was 35 mN as shown in Table 1. The static pressure in the airflow passage 9 at the downstream end 8 on the airflow injection port was −7.2 kPa.

The properties of the obtained polypropylene long fiber were as follows: the single fiber diameter was 17.4 μm, and the spinning speed calculated from this was 2816 m / min.

[Example 4]
One passage forming surface of the pair of outer wall members 5 forming the air flow passage 9 is formed by a continuous single plane parallel to the traveling yarn direction between the second air flow passage 11 and the fourth air flow passage 13. The same pattern as that of Example 1 was used except that a stretching apparatus 3 as shown in FIG.

As a result of measuring the traction force, it was 39 mN as shown in Table 1. The static pressure in the airflow passage 9 at the downstream end 8 on the airflow injection port was −6.5 kPa.

The properties of the obtained polypropylene long fiber were a single fiber diameter of 16.3 μm, and a spinning speed calculated from this was 3,005 m / min.

[Comparative Example 1]
As a pattern which does not expand the second airflow passage, the gap W ₂ of the

second airflow passage

11 and 4 mm, the cross-sectional shape of the second air flow passage and the third air flow passage in FIG. 2, except that the cross-sectional area was set to the same Same as Example 1.

As a result of measuring the tractive force, it was 34 mN as shown in Table 1. The static pressure in the airflow passage 9 at the downstream end 8 on the airflow injection port was −7.0 kPa.

The properties of the obtained polypropylene long fiber were a single fiber diameter of 17.6 μm, and a spinning speed calculated from this was 2,783 m / min.

[Comparative Example 2]
Not larger fourth airflow channel 13 (i.e., not provided substantially fourth airflow passage) as a pattern, a gap W ₄ of the fourth

air flow path

13 and 4 mm, the third air flow passage and the fourth air flow path in FIG. 2 Example 1 was the same as Example 1 except that the cross-sectional shape and the cross-sectional area were the same.

As a result of measuring the traction force, it was 30 mN as shown in Table 1. The static pressure in the airflow passage 9 at the downstream end 8 on the airflow injection port was −5.8 kPa.

The properties of the obtained polypropylene long fiber were as follows: the single fiber fiber diameter was 18.6 μm, and the spinning speed calculated from this was 2,634 m / min.

[Comparative Example 3]
As a pattern in which the second airflow passage 11 is longer than the third airflow passage 12 and the fourth airflow passage 13, the length L from the inlet 14 to the outlet 15 of the airflow passage 9 is 200 mm, and the length of the second airflow passage 11 is long. It is 75mm and _{L 2,} the length _{L 3} of the 25mm of the third airflow passageway 12, except that the length _{L 4} of the fourth air flow path 13 and 50mm were the same as in example 1.

As a result of measuring the traction force, it was 32 mN as shown in Table 1. The static pressure in the airflow passage 9 at the downstream end 8 on the airflow injection port was −5.5 kPa. As for the properties of the obtained polypropylene long fiber, the single fiber fiber diameter was 18.1 μm, and the spinning speed calculated from this was 2,707 m / min.

[Comparative Example 4]
As a pattern in which the fourth airflow passage 13 is longer than the second airflow passage 11 and the third airflow passage 12, the length L from the inlet 14 to the outlet 15 of the airflow passage 9 is 200 mm, and the length of the second airflow passage 11 is long. It is 32.5mm and _{L 2,} the length _{L 3} of the third airflow passageway 12 32.5mm, except that the length _{L 4} of the fourth air flow path 13 and 75mm were the same as in example 1.

As a result of measuring the traction force, it was 31 mN as shown in Table 1. In addition, the static pressure in the airflow passage 9 at the downstream end 8 of the airflow injection port was −6.6 kPa.

The properties of the obtained polypropylene long fiber were as follows: the single fiber fiber diameter was 18.4 μm, and the spinning speed calculated from this was 2,663 m / min.

The stretching device of the present invention can be applied not only to stretching yarns for nonwoven fabrics but also to stretching yarns for other uses such as various woven and knitted fabrics.

1: Spinneret 2: Thread 3: Stretching device 4: Conveyor 5: Outer wall member 6: Buffer of airflow supply unit 7: Airflow injection port 8: Downstream side end of airflow injection port 9: Airflow passage 10: First airflow passage 11: Second airflow passage 12: Third airflow passage 13: Fourth airflow passage
14: Inlet 15: Outlet 16: Tension meter 17: Teggs 18: Static pressure measuring port 19: Cooling device 20: Side wall member 90: Passage forming surface

Claims

A drawing device that draws an air flow inward from the outside of the running path of the yarn in a passage having a yarn inlet and outlet obtained by melt spinning the thermoplastic polymer. The passage having the yarn inlet and the outlet includes the first airflow passage, the airflow injection port, the second airflow passage, the third airflow passage, and the fourth airflow passage in this order with respect to the yarn traveling direction. A stretching apparatus that is continuously provided and satisfies the following (i) to (iv):
(I) The third airflow passage has a constant flow path cross-sectional area with respect to the yarn traveling direction.
(Ii) The second airflow passage has a flow passage cross-sectional area smaller than that of the third airflow passage, and the flow passage cross-sectional area is constant and / or gradually increased with respect to the yarn traveling direction.
(Iii) The fourth airflow passage has a flow passage cross-sectional area larger than that of the third airflow passage, and the flow passage cross-sectional area is constant and / or gradually increased with respect to the yarn traveling direction.
(Iv) the length L 2 of the yarn running direction of the second air flow passage, the length of the third and the yarn running direction of the length L 3 of the air flow passage, the yarn running direction of the fourth air flow path L 4 satisfies the following relational expression.
(L 3 + L 4 ) / (L 2 + L 3 + L 4 ) ≧ 0.6
L 4 / (L 2 + L 3 + L 4 ) ≦ 0.4
The stretching apparatus according to claim 1, wherein a sum (mm) of L 2 , L 3, and L 4 satisfies the following relational expression.
L 2 + L 3 + L 4 ≧ 100
The minimum flow path cross-sectional area H 2MIN of the second air flow path, the flow path cross-sectional area H 3 of the third air flow path, and the maximum flow cross-sectional area H 4MAX of the fourth air flow path satisfy the following relational expression: The stretching apparatus according to claim 1 or 2.
1.05 ≦ H 3 / H 2MIN
1.05 ≦ H 4MAX / H 3
The passage having the yarn inlet and outlet is formed by a pair of opposed outer wall members, and one passage forming surface of the pair of outer wall members is formed from the second airflow passage to the fourth in the yarn traveling direction. The stretching apparatus according to any one of claims 1 to 3, wherein a space to the airflow passage is formed by a continuous single plane parallel to the yarn traveling direction.
An apparatus for producing a fiber, comprising: a spinneret, a cooling device for spun yarn, and a drawing device according to any one of claims 1 to 4 in this order in a yarn traveling direction.
A spinneret, a device for cooling the spun yarn, a drawing device according to any one of claims 1 to 4, and a fiber web conveyor provided with a net in this order in the yarn running direction. Fiber web production equipment.
A fiber is formed by melt spinning a thermoplastic polymer from a spinneret, and after cooling and solidifying the yarn, the yarn is drawn by the drawing device according to any one of claims 1 to 4. Production method.
A method for producing a fiber web, comprising producing a fiber web using the apparatus according to any one of claims 1 to 6.