JPS6238020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nozzle for discharging a molten thermosoftening material, which is used in an apparatus for producing fibers from a thermosoftening material.

More specifically, the whole includes an orifice for discharging a molten thermosoftening material, a gas ejection orifice provided near the periphery of the orifice, and a passage for supplying gas to the gas ejection orifice. The present invention relates to a nozzle for discharging a heat-softening substance, which has an elongated structure, and when it is energized in the longitudinal direction to generate heat, the amount of heat generated varies in the longitudinal direction, thereby preferably controlling the temperature difference in the longitudinal direction.

Conventionally, a molten heat-softening material is discharged from an orifice, and a gas jet is ejected from a gas jetting orifice provided near the orifice to hit the discharged heat-softening material. Several methods and devices for finer fibrillation are known (for example, the "TOR" method described in Japanese Patent Publication No. 52-43932, or the
52-25113 and the so-called "rotary gas jet" described in U.S. Pat. No. 4,135,903.
(see laws, etc.).

In these devices, in order to give the discharged molten heat-softening material effective momentum for finerization by the gas jet, an orifice for discharging the gas jet is replaced with an orifice for discharging the molten heat-softenable material. It is advantageous to use a nozzle having a large number of orifices for discharging the heat-softening material and gas ejection orifices in order to further increase the production of fibers.

However, for convenience in manufacturing the nozzle or in the fibrillation operation, these orifices are arranged in rows, so the structure as a whole is elongated, and each orifice is arranged in a row along the length of the nozzle. Preferably, nozzles are used which are provided with a common gas flow path communicating with the orifice. During the actual fibrillation operation, these nozzles are removably or integrally attached to the bottom of the pot that melts the heat-softening substance, and are heated by electricity to maintain a sufficient temperature. There are many. However, these nozzles have an elongated structure, and the gas that flows through them and is supplied to the gas ejection orifice (the temperature of this gas is generally lower than the melting temperature of the thermoplastic material) Since heat is removed by the nozzle, a large amount of heat is removed especially near the inlet where the gas flows into the gas flow path, resulting in a disadvantage that a large temperature difference occurs in the longitudinal direction of the nozzle.

Therefore, the present inventor conducted research in order to solve the above-mentioned drawbacks of the elongated structure of the nozzle, which is equipped with a large number of orifices arranged in a row, and is used to produce fibers from such heat-softening materials. As a result, the cross-sectional area of the nozzle in the direction perpendicular to the longitudinal direction of the nozzle is gradually changed in the longitudinal direction of the nozzle, and the cross-sectional area is gradually increased in the direction away from the gas inlet to the gas passage. The present invention was achieved by discovering that it is possible to maximize the amount of heat generated near the inlet and thereby minimize the temperature difference in the longitudinal direction of the nozzle.

That is, the present invention relates to a nozzle used in an apparatus for producing fibers from a heat-softening substance, which comprises a plurality of orifices for discharging a molten heat-softenable substance, and a plurality of individual orifices. and a gas flow path for supplying gas to the gas ejection orifice. The nozzle as a whole has an elongated structure, and the passage extends along the longitudinal direction of the nozzle, and the passage extends from the gas inlet of the passage in a direction away from the gas inlet. The cross-sectional area in the direction perpendicular to the longitudinal direction of the nozzle gradually increases toward This is a nozzle for discharging a molten heat-softening material, which is characterized in that the amount of heat generated by energization gradually decreases in the direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A nozzle for discharging a heat-softening material according to the present invention will be explained with reference to the accompanying drawings.

FIG. 1 of the accompanying drawings shows a schematic diagram of a nozzle for discharging a thermoplastic substance according to the present invention. FIG. 1a is an overall perspective view, FIG. 1b is a sectional view of the vicinity of the end in the direction perpendicular to the longitudinal direction, and FIG. 1c is a sectional view of the vicinity of the center part in the direction perpendicular to the longitudinal direction.

In FIG. 1a, a nozzle 1 for dispensing a thermosoftening material according to the invention, which is attached (removably or as one piece) to the lower part of a melting pot 11 for a thermosoftening material, is connected to a nozzle 1 for discharging a thermoplastic material supplied from the melting pot 11. At the same time, the heat softening substance is discharged from the outlet 3 through the orifice 2, and at the same time, the gas is introduced from the gas inlets 5, 5', through the chambers 7, 7', to the conduits 8, 8' bored in the lower wall of the nozzle 1. The gas is ejected as jet gas from the gas ejection orifices 9, 9'.
The molten thermosoftening material discharged from the outlet 3 of the orifice 2 collides with the jet gas discharged from the gas discharge orifices 9, 9', and is strongly stretched and finely divided. Nozzle 1 is terminal 1
0 and 10', and is heated to a temperature higher than the melting temperature of the heat-softening material.

In FIG. 1a, the heat softening substance discharge nozzle 1 of the present invention is supplied with gas from both ends in the longitudinal direction, and therefore the amount of heat taken away by the gas at both ends is greater than the amount of heat at the center. Therefore, the thickness of the side wall 12 at both ends of the nozzle is made thinner than the thickness of the side wall 13 at the center of the nozzle, and by reducing the effective current-carrying area at both ends of the nozzle, the electric resistance is increased and the electrical resistance at both ends is made smaller. It is designed to generate a large amount of heat. According to the cross-sectional views of the nozzle of the present invention shown in FIGS. 1b and 1c, the nozzle of the present invention in FIG. 1a has a small effective current-carrying area at both ends and a large effective current-carrying area at the center. I understand this clearly. In this way, the nozzle of the present invention has a cross-sectional area that gradually changes in the longitudinal direction of the nozzle.
The nozzle of the invention in FIG.
1 orifice for discharging molten thermoplastic material
Although the nozzle of the present invention is shown arranged in a row, the number of such orifices in the nozzle of the present invention is not limited, and the orifices need not be in one row, but may be in a plurality of rows. This is because, as mentioned above, the greatest feature of the nozzle of the present invention is that the cross-sectional area is changed in the longitudinal direction to gradually change the amount of heat generated by energization in order to compensate for the amount of heat taken away by the gas. This can be understood from the fact that it is unrelated to the number of orifices or the number of orifice rows.

From the comparison between FIG. 1b and FIG. 1c, it can be seen that the nozzle of the present invention in FIG. 1 has almost the same wall thickness at the bottom of the nozzle having the orifice for discharging the molten thermoplastic material, the gas flow passage, and the gas ejection orifice. I understand that.

In order to vary the longitudinal cross-sectional area of the nozzle of the present invention, it is thus possible to have equal or nearly equal wall thicknesses at the base of the nozzle and varying wall thicknesses at the side walls. preferable. In such a nozzle of the present invention, the orifice lengths of the orifice for discharging the molten heat-softening material and the gas ejection orifice provided at the bottom of the nozzle can be made equal or almost equal over the entire longitudinal direction of the nozzle. Therefore, it is not only preferable for the construction of the nozzle, but also has the advantage of stably discharging the molten heat-softening material and ejecting the gas jet. However, it will be understood that the nozzle of the present invention is not limited to such a nozzle having equal bottom wall thickness.

As described above, in the nozzle of the present invention, the cross-sectional area in the direction perpendicular to the longitudinal direction of the nozzle gradually changes.
In the nozzle of FIG. 1a, the gas introduced into the passages 8, 8' of the nozzle is conducted through gas inlets 5, 5' provided at both ends of the nozzle, and the cross-sectional area of the nozzle extends from the ends of the nozzle to the center. The number gradually increases towards the end.

The nozzle of the present invention is characterized by the fact that gas, which is generally lower than the melting temperature of a thermosoftening material such as glass, is introduced into the gas passages 8, 8' provided in the nozzle in the longitudinal direction of the nozzle. Heat is taken away. The gas is guided into the gas passage and gradually increases in temperature as it absorbs heat from the nozzle until it is ejected from the gas ejection orifice. Therefore, the amount of heat taken by the gas from the nozzle is greatest at the point where the gas is introduced into the gas passage, and gradually decreases as it moves away from there.

Therefore, the nozzle of the present invention is not limited to having a maximum cross-sectional area at the center in the longitudinal direction as shown in FIG. 1a. The area is gradually changing. For example, in addition to the nozzle shown in FIG. 1a, the following nozzles can be used as the nozzle of the present invention.

A nozzle of the type shown in Figure 1a,
A nozzle in which one end of the gas passage 8, 8' is closed, for example the end on the left in the figure, so that gas can only be introduced from the gas inlet 5' at the other end. In such a nozzle, the longitudinal cross-sectional area of the nozzle gradually increases from one end into which gas flows toward the other end.

Alternatively, a nozzle having a gas inlet at the center in the longitudinal direction may be used, and such a nozzle has the smallest cross-sectional area at the center in the longitudinal direction and the largest at both ends.

A plurality of orifices for discharging a molten thermosoftening substance, a gas ejection orifice provided near each orifice of the plurality of orifices, and a gas flow passage for supplying gas to the gas ejection orifice. In the nozzle of the present invention, which has an elongated structure as a whole because the plurality of orifices are arranged in a row, the gas inlet for introducing gas into the gas flow passage is connected to one of the longitudinal directions. From the above description, it will be easy to decide where to provide the grooves and how to change the longitudinal cross-sectional area in that case. The nozzle of the present invention includes a nozzle in which the cross-sectional area is the smallest at the position of the gas inlet, and the cross-sectional area gradually increases away from the gas inlet, regardless of the position of the gas inlet.

The nozzle of the present invention will be described in more detail regarding the case where glass fibers are manufactured from glass, which is a thermosoftening substance, using the nozzle of the present invention.

The nozzle is made of a material such as platinum, rhodium, palladium, indium, iron, nickel, chromium, manganese, or an alloy thereof, preferably a noble metal material such as platinum, rhodium, or palladium. The pitch between the nozzles that discharges molten glass is usually 2.5 to 10 mm, preferably 5 to 10 mm.
It is 7mm.

The type of nozzle shown in Figure 1 in which gas is introduced from both ends of the nozzle is usually preferably used, although it varies slightly depending on the longitudinal length of the nozzle.
In the case of a nozzle having a length of about 200 to 400 mm, the cross-sectional area at the center of the nozzle is about 1.1 to 3 times, preferably about 1.2 to 2 times, the cross-sectional area at both ends.

The melting temperature of glass naturally varies depending on the composition of the glass, but for example, the temperature of molten glass at the glass discharge orifice is usually 1200 to 1400°C, whereas the temperature of the gas introduced into the nozzle depends on the heat resistance of the gas generation equipment or piping. Due to the limitations of nature, the upper limit is at most about 1000°C, and therefore preferably about 500 to about 900°C.

Thus, when the nozzle for discharging a thermosoftening substance of the present invention is used, the amount of heat carried away by the gas introduced into the nozzle is gradually increased in cross-sectional area in the direction away from the region where the gas inlet is located. Therefore, when the surface is heated by electricity from the edge,
The amount of heat generated is greatest at the location where the gas inlet is located and gradually decreases in the direction away from there, making it possible to maintain a uniform temperature throughout the nozzle.

Therefore, according to the nozzle of the present invention, the flow rate and temperature of the heat-softening material discharged from each heat-softening material discharge orifice of the nozzle can be maintained uniformly, and the quality of the heat-softening material is improved. of fibers are obtained.

In addition, all of the orifices for discharging heat-softening substances in the nozzle can be maintained under optimal temperature conditions, reducing the gas pressure ejected from the gas ejection orifice by approximately 10% compared to conventional nozzles. can achieve the same level of productivity.

Furthermore, in conventional nozzles, the longer the length in the longitudinal direction, the more uneven the temperature in the longitudinal direction becomes, which naturally limits the length; however, according to the nozzle of the present invention, the temperature in the longitudinal direction can be reduced. It is possible to maintain uniformity, and therefore it has become possible to increase the number of orifices and increase the size of the orifices, thereby increasing the productivity per fiberizing device.

The thermosoftening substances that can be made into fibers by the nozzle of the present invention include, in addition to glass, other thermoplastic resins such as oriolefins. Preferably used.

Further, the nozzle of the present invention can be used in the Tor method or the rotary gas jet method, and can be used not only for producing short fibers but also for producing long fibers.

[Brief explanation of the drawing]

FIG. 1a is a schematic overall perspective view of a nozzle for discharging a heat-softening material according to the present invention. FIG. 1b is a sectional view of the nozzle of FIG. 1a near the end in the direction perpendicular to the longitudinal direction, and FIG. 1c is a sectional view of the nozzle of FIG. 1a near the center in the direction perpendicular to the longitudinal direction.

Claims (1)

[Claims] 1 A nozzle used in an apparatus for producing fibers from a thermosoftening substance, which includes a plurality of orifices for discharging a molten thermosoftenment substance, and a nozzle provided near each orifice of the plurality of orifices. and a gas flow passage for supplying gas to the gas ejection orifice, and the plurality of orifices for ejecting the molten thermoplastic substance are arranged in a row. The nozzle as a whole has an elongated structure, and the passage extends along the longitudinal direction of the nozzle, and the passage extends from the gas inlet of the passage in the direction away from the gas inlet in the longitudinal direction of the nozzle. The cross-sectional area in the direction perpendicular to the passage gradually increases, so that when the nozzle is energized from both longitudinal ends to generate heat, the amount of energized heat increases from the gas inlet of the passage in the direction away from the gas inlet. A nozzle for discharging a molten heat-softening material, characterized in that: gradually decreases.