JPS6123284B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a melt blow spinning apparatus for fiber-forming thermoplastic resin, and more particularly, the present invention relates to a melt-blowing spinning apparatus for fiber-forming thermoplastic resin, and more particularly, the fiber-forming thermoplastic resin is spun in a molten state through an orifice of a heated die using a high-temperature jet gas fluid. The present invention relates to a spinning device which is particularly effective when producing a wide nonwoven fabric mat, in which the polymer is extruded into fine particles and then aggregated by an accumulating device.

The melt blowing method has been reported by Van A. Vuente (Industrial Engineering Chemistry, Vol. 48, No. 8, pp. 1342-1346). Further, patents related to the spinning method are disclosed in British Patent No. 1055187, Japanese Patent Publication No. 7883/1983, Japanese Patent Application Laid-Open No. 48921/1977, and Japanese Patent Application Laid-open No. 46972/1989.

For example, JP-A-50-46972 states that in order to produce high-quality pine by the melt blowing method, (a) specific operating conditions, (b) apparent viscosity of the polymer, (c) flow rate of the polymer, (d) gas It is clearly shown that the selection of the correlation with flow velocity is important. As is clear from these documents and patents, in order to obtain a high quality widened nonwoven fabric mat in the melt blowing method, (a) polymer flow rate, (b) polymer viscosity, (c) polymer temperature, (d)
A device is required to maintain a specific relationship between the propellant gas flow rate and (e) the propellant gas temperature.

However, in the conventional technology,
As shown in No. 48921, various considerations have been made regarding the orifice section that is the polymer spinning head and the slit section that is the injection port for the propellant gas, but the width has been widened and there are problems such as unevenness in weight, polymer beads, and quality unevenness. The above (a) ~ necessary to produce non-woven matte
This is insufficient to obtain the correlation in (e). That is, the melt blow spinning apparatus of the prior art has the embodiment shown in FIGS. 1 and 2, in which polymer is supplied into the die 1 from the polymer inlet 5 and spun by a manifold 6 with a flow path formed in the spinning width direction. After being distributed in the width direction, narrow slit-shaped lands 7
The fibers are spun from the orifice 8.

Therefore, the flow path length of the polymer discharged from the orifice 8 clearly differs between the center and the ends in the spinning width direction, resulting in a difference in residence time. Furthermore, since the heating history is different, the structure is such that unevenness in the temperature, viscosity, flow rate, etc. of the polymer tends to occur in the spinning width direction. Furthermore, there is no mechanism for adjusting the polymer flow rate in the spinning width direction in the polymer flow path, and once the shape and dimensions of the polymer flow path are determined, it is impossible to adjust the polymer discharge amount in the spinning width direction.

Further, the temperature of the polymer inside the die 1 is adjusted by heating the die 1 with the heating element 3. The heating element 3 is generally an electric heater, and when the spinning width is wide, the electric heater is divided in the spinning width direction and the heating capacity is adjusted for each divided block. The temperature of the polymer in the width direction is controlled by heating, and therefore the temperature of the polymer depends on the accuracy of temperature control of the electric heater. In this method, it is very difficult to maintain the dies 1 having different heat capacities at a uniform temperature in the spinning width direction.

Further, the heating gas is supplied from the gas inlet 9, fills the gas header 10 provided along the spinning width direction, and is injected from the slit 11. In this gas supply method, the flow of the heating gas is
Within 0, flow rate unevenness in the spinning width direction is likely to occur, and temperature unevenness is also likely to occur in accordance with flow rate unevenness. Furthermore, it is necessary to maintain the temperature of the polymer and the heating gas at arbitrary temperatures, but in the conventional method, the die 1 and the gas header 10 are not insulated, and the heating element 3 maintains the temperature of both the polymer and the heating gas. It is structured to have an impact.

The present inventors conducted various studies to solve these drawbacks, and as a result, discovered the present invention. That is, the present invention provides a spinneret block equipped with a spinning orifice and a heated gas injection slit, a gear pump that supplies polymer to the orifice through a polymer flow path, and a spin block that incorporates a gas header that distributes heated gas to the slit.
The melt blowing apparatus consists of a heating jacket containing a polymer conduit connected to the gear pump.

Further, the gist and preferred embodiments of the present invention will be explained below.

The polymer flow path from the polymer inlet to the spinneret block is communicated via a polymer conduit, a gear pump, and a polymer introduction hole, and by creating multiple flow paths, the length of each flow path is made approximately the same, and each flow path is It was possible to make the polymer residence time in the channel uniform. Moreover, a gear pump is interposed in each flow path, and by adjusting the discharge amount of the gear pump, it has become possible to adjust the polymer flow path of each polymer flow path. Next, by providing a jacket along the spinning width direction, heating with a heat transfer medium becomes possible, and by vaporizing and heating the heat transfer medium, uniform heating can be achieved along the spinning width direction. Summer. Furthermore, by insulating the gas header with a heat insulator,
It became possible to maintain the polymer temperature in the spin block and the gas temperature in the gas header at arbitrary high temperatures.

The term "polymer" as used in the present invention refers to fiber-forming thermoplastic resins such as polyamide, polyester, polyethylene polypropylene, polycarbonate, polyacrylic, polyvinyl, and copolymers or mixtures thereof, in the form of a heated melt. Favorable results can be obtained in the case of condensation polymers such as polyamides and polyesters whose viscosity tends to change depending on residence time. Heated gas is superheated steam,
Refers to heated inert gas, heated air, etc. Heat transfer medium refers to commonly used product names such as Dowsome A and Therm-S-300, and heat insulator refers to asbestos, calcium silicate, asbestos glass wool, etc., which are generally used for high-temperature insulation and heat retention. .

Next, the embodiments of the present invention will be described in detail with reference to the drawings. Figures 3 and 4 show an example of a melt blow spinning apparatus according to the present invention, and Figure 3 is a longitudinal cross-sectional view perpendicular to the spinning width direction. FIG. 4 is a part of a longitudinal cross-sectional view along the spinning width direction.

First, referring to FIGS. 3 and 4, the spin block 12 is a one-piece block that is elongated in the spinning width direction, and a gear pump 13 is attached to the top surface of the block with a large number of mounting bolts. A plurality of gear pumps 13 may be provided along the spinning width. A spinneret block 14 is attached to the lower surface with a large number of mounting bolts, and the discharge port of the gear pump 13 and the polymer inlet in the spinneret block 14 are connected to a multi-line polymer channel 21 bored in the spinneret block 12. and is communicated via the packing 22. Further, the upper side of the spin block 12 is provided with a jacket 16 to support the spin block 1.
A jacket chamber 18 is formed over the jacket 2, a polymer inlet 5 is provided on the outside of the jacket 16, and a polymer conduit 19 is provided within the jacket chamber 18. The polymer conduit 19 branches from the polymer inlet 5 into a number corresponding to the number of gear pumps 13, and communicates with the suction port of the gear pump 13 via a polymer passage hole 20 bored in the spin block 12. Furthermore, the polymer conduit 19 is
The jacket chambers 18 are arranged so that each pipe length is the same.
It is bent inside. It is therefore branched off by a polymer conduit 19, enters a gear pump 13, and further branched off by a polymer channel 21 and flows into a spinneret block 14. Therefore, it was possible to eliminate the extreme difference in channel length, which is a drawback of the prior art. However, even in the present invention, there is a slight difference in the length of the polymer flow path 21, but if further improvement is desired, the diameter of each polymer flow path may be changed so that the polymer residence time in the polymer flow path 21 is the same. Just set it. Furthermore, by providing a plurality of gear pumps 13, it became possible to adjust the discharge amount in the spinning width direction. Further, a wear plate may be interposed between the spin block 12 and the gear pump 13 or the spinneret block 14.

Further explaining the spinneret block 14, the spinneret block 14 includes a distribution pack 23, a spinneret 25, and a gas cover plate 2 stacked together and assembled with mounting bolts.
A large number of polymer distribution grooves that widen toward the end are arranged along the spinning width direction, and the base side of the grooves that widen toward the end serves as a polymer inlet, and each inlet communicates with the polymer flow path 21. Furthermore, a polymer communication groove 27 communicating in the spinning width direction is formed on the end-widening side. In addition, the distribution pack 23
A spinneret 25 is connected to the lower surface of the spinneret 25, and a land 7, which is a slit-shaped groove in the spinning width direction, is perforated in the spinneret 25, and has an opening area equivalent to that of the lower surface of the polymer communication groove 27. The lengths of the lands 7 are all made equal, and orifices 8 of uniform diameter and arranged at minute intervals are bored in the lower part of the lands 7 on a straight line along the spinning width.

Therefore, from the gear pump 13, the polymer flow path 2
The polymer sent through the distribution pack 23
After flowing into the polymer communication groove 27 and the land 7
filled with. The polymer flowing into land 7 becomes a uniform flow in the spinning width direction, and flows through orifice 8.
Uniform discharge is performed in the spinning width direction.

Next, a plurality of heating elements 3 are disposed at the bottom of the jacket chamber 18, and a heat transfer medium 32 is enclosed so that the heating elements 3 are immersed therein. It is preferable to use an electric heater as the heating element 3. During steady operation, the heating element 3 heats the heat transfer medium 32, generates steam at a desired temperature, and heats the jacket chamber 18.
The interior is made into a steam chamber with an equal temperature, and the spin block 12 is heated using the condensation heat transfer of the steam. Therefore, the spin block 12 can be heated uniformly in the spinning width direction. The means for generating steam is not limited to this example, and it is also possible to use a steam generator other than this example.

Although not shown in the drawings, accessories such as a heat transfer medium inlet/outlet nozzle, a safety valve attachment nozzle, a liquid level gauge attachment nozzle, a temperature and pressure gauge attachment nozzle are attached to the outer surface of the jacket 16.

Next, a pair of gas headers 15 are bored in the spin block 12 along the spinning width direction with the spinneret block 14 in between.
The inner or outer surface is covered and insulated by a heat insulator 29. Gas inlets 9 are provided at both ends of this header. The gas inlet 9 may be provided only at one end. A large number of discharge holes 30 are arranged diagonally downward in the gas header 15 at minute equal intervals.
A gas passage 31 is formed at the outlet of the discharge hole 30 by a spinneret block 14 and a gas cover plate 2 provided to cover the lower surface of the spin block 12, and a gas passage 31 is formed at the outlet of the discharge hole 30 by a spinneret 25 and a gas cover plate 2. A slit 11 having a uniform narrow width is formed on both outer surfaces of the fiber 8 along the spinning width direction. Therefore, the gas at the same temperature supplied to the gas inlet 9 fills the gas header 15, is distributed along the spinning width direction, and flows into the gas passage 31 from the discharge hole 30 to fill it.

Next, it is injected from the slit 11 in the spinning width direction at a uniform temperature and flow rate.

Further, the gas header 15 is insulated from the spin block 12 by a heat insulator 29. Therefore, the temperature of the gas flowing in the gas header 15 and the temperature of the polymer flowing in the spin block 12 can each be maintained at arbitrarily high temperatures.

Next, although not shown in the drawing, the gas cover plate 2 is designed so that the spacing between the slits 11 can be finely adjusted by means of a number of push-pull bolts horizontally attached at regular intervals to the bottom surface of the spin block 12. .

The outer periphery of the above-mentioned spinning apparatus of the present invention is covered with a heat insulator 4 except for the lower surface of the spinneret block 14, and is designed to reduce heat radiation. Further, a pair of lower surface heat insulators 38 are attached to the lower surface of the spinneret block 14 by butterfly plates 37, so that when the mounting bolts are removed, the spinneret block 14 can be opened downward. Therefore, by opening the lower heat insulator 38, the spinneret block 14 can be easily attached and detached, and furthermore, the gas cover plate 2 can be easily adjusted.

In the present invention, the positions of the polymer inlet 5, gear pump 13, heating element 3, gas header 15, etc., as well as the shapes of the jacket 16, spin block 12, etc., are not restricted by the contents of FIGS. The gear pump 13 may be attached to the side surface of the spin block 12, or the shape of the jacket 16 may be changed to place the heating element 3 in a horizontal position of the gas header 15. It is also possible to provide the headers 15 on both outer sides of the spin block 12. Furthermore, a polymer flow path 21, a gear pump 13,
The number of polymer conduction holes 20, channels 21, etc. can be arbitrarily determined depending on the spinning width.

According to the present invention, there is no difference in residence time of the polymer in the spinning machine, and there is also no difference in heating temperature in the spinning width direction, thereby eliminating uneven viscosity of the polymer and making it possible to make the amount of polymer discharged in the spinning width direction uniform. Ta. Furthermore, by interposing a gear pump in the polymer flow path, it became possible to adjust the polymer flow rate in the spinning width direction.
Furthermore, it was possible to maintain the polymer temperature and the gas temperature at arbitrary high temperatures, and to eliminate unevenness in the gas temperature in the spinning width direction.

Therefore, it is possible to produce high-quality non-woven mats with a uniform basis weight in the direction of the spinning width and without polymer beads.Also, by arbitrarily setting the number of gear pumps and the spinning width of the orifice, it is possible to produce yarn of any width. It became possible to produce non-woven matte.

[Brief explanation of the drawing]

Figures 1 and 2 show an example of a melt blow spinning device according to the prior art, with Figure 1 being a longitudinal sectional view perpendicular to the spinning width direction, and Figure 2 being a longitudinal sectional view along the spinning width direction. . 3 and 4 show an example of a melt blow spinning apparatus according to the present invention, in which FIG. 3 is a longitudinal sectional view perpendicular to the spinning width direction, and FIG. 4 is a longitudinal sectional view along the spinning width direction. . 1...Die, 2...Gas cover plate, 3...
...Heating body, 4... Heat retaining body, 5... Polymer inlet,
6... Manifold, 7... Land, 8... Orifice, 9... Gas inlet, 10... Gas header, 11... Slit, 12... Spin block, 13... Gear pump, 14... Spinneret block, 15 . . . Gas header, 16 . Base, 27...Polymer communication groove, 29...Insulator, 30...Drain hole, 31...
Gas passage, 32... Heat transfer medium, 37... Hinge, 3
8...Lower surface heat insulator.

Claims (1)

[Claims] 1 A spinneret block 14 equipped with a spinning orifice 8 and a heated gas injection slit 11, and a polymer flow path 2 branched into a plurality of lines in the orifice 8.
a spin block 12 containing a gear pump 13 for supplying polymer through the slit 11 and a gas header 15 distributing heated gas to the slit 11 and insulated by a heat insulator 29;
3. A melt blow spinning apparatus comprising a jacket chamber 18 containing a polymer conduit 19 connected to a jacket chamber 18.