JPS5854099B2 - Equipment for manufacturing fibers made from thermosoftening substances - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing fibers from a heat-softening substance and a method for producing fibers from a heat-softening substance by applying a swirling gas flow to the substance. Method for producing fibers of softening substances - JP-A-52-25113J Hereinafter referred to as swirling gas jet method.

) Regarding the shape of the gas flow nozzle used in

In recent years, a swirling gas jet method has been proposed as a method for thinning heat-softening materials into fibers.

The contents of this method are as follows: A cylindrical flow of a heat-softening material is brought into contact with a gas flow having a component in the tangential direction of the outer periphery of the cross section in the direction of travel, while the material is moved at high speed. This is a method that uses centrifugal force to pull out the narrowed filamentous material by spinning it with a
It has become clear that this method is extremely advantageous in terms of production efficiency, product quality, etc. compared to rotary methods (or centrifugal methods), etc.

More specifically, the swirling gas jet method consists of continuously flowing out a melt of a heat-softening material, and in a first zone along the progress of the melt that flows out, the melt is exposed to the outer circumference of its cross section. a gas flow having a tangential component of contacting the melt in a manner that prevents lateral displacement of the melt;
rotating the melt about a central axis in the direction of melt travel while confining the melt in a defined position, thereby creating a second zone following the melt travel from said first zone.
In the area, the melt is ejected laterally by centrifugal force due to rotation mainly based on the inertia of the rotational force, and the ejection direction is in the circumferential direction as seen from the central axis and in the same direction as the rotation. This is a method for producing fibers of a heat-softening material, characterized in that fibers of a heat-softening material are continuously drawn out from a molten material by rotation.

This method more preferably includes continuously flowing out the melt of the thermosoftening material from a melt nozzle or the tip of a heated rod of the thermosoftening material with a cross-sectional diameter of 0.5 to LOmyn, and A gas flow having a component tangential to the cross-sectional circumference of the melt in a first zone along the progress of the melt and a component approaching the central axis of the melt along the progress of the melt is passed through the melt nozzle. The distance between the tip of the rod of thermosoftening material or the tip of the rod of thermosoftening material and the position where said gas flow is closest to the central axis of the advancing melt is the inner diameter of the melt nozzle or the diameter of the rod of thermosoftening material. 0 of
．． The central axis of the melt is 2 to 10 times larger and in contact to prevent lateral displacement of the melt, confining the melt in a limited position and forming a tapered conical shape. , whereby in a second zone following the melt progress from said first zone, the melt is shaped into a conical shape by centrifugal force due to rotation, mainly due to the inertia of said rotational force. The fibers of the thermosoftening substance are continuously drawn out from the melt by causing them to fly out laterally from the tapered tip, and then rotating in the circumferential direction as seen from the central axis and in the same direction as the rotation. This is a method for producing fibers of a heat-softening substance.

As the shape of the nozzle for ejecting a gas flow used in the swirling gas jet method, a ring-shaped nozzle and a gas flow nozzle that ejects a gas flow only in a single direction and are composed of three or more nozzles have been proposed, but the present invention concerns the latter.

In the swirling gas jet method, as shown in FIGS. 1 and 2, first, a cylindrical flow 3 of a melt of a thermosoftening material is continuously flowed out or discharged from a nozzle 2.

A gas flow nozzle 1 that spouts a gas flow only in a single direction and is composed of three or more, e.g. The central axis is 2 to the central axis of the melt nozzle.
They are arranged so as to be inclined at an angle of 0 to 700 degrees.

The gas flow 5 ejected from the gas flow nozzle 1 is a molten columnar flow 3
It has a tangential component (hereinafter referred to as the rotational component of the gas flow) of the outer circumference of the cross section that crosses the central axis of the gas flow.

Furthermore, as the melt progresses, the gas flow center line position (highest density energy part 13
There is a first zone in which the gas flow is controlled such that the distance to the centerline position of

Twice the average length of the distance at each position measured using the above method is called the total gas flow diameter at that position.

Furthermore, the distance from the extension line of the traveling axis of the melt in the first zone to the gas flow measured in the same manner as above, that is, the diameter of the total gas flow, gradually increases as the melt moves downward in the traveling direction. There is a second area that has become.

The position where the diameter of the total gas flow is smallest is called the focal point 6.

In the first zone, the melt is rotated and confined in a limited position by the gas flow, forming a tapered conical shape, so-called cone 4, and in the second zone, the confining force of the gas flow is no longer present, so that the cone is closed. The filament formed at the tip is subjected to a stronger rotational force by the rotating component of the gas flow, rotates around the tip of the cone, absorbs some of the high-density energy of the gas flow, and is carried away in the direction of gas flow. , the filament is drawn into a thin fiber 8.

By the way, in order to obtain a cone with a stable and constant shape in the first zone and also to form a continuous filament from the tip of the cone, the gas flow surrounding the melt and ejecting only in a single direction is required to melt the melt at least within the focal point. Things should not collide to the extent that they interfere with the smooth progress of things.

Preferably, they should enter the second area and collide with each other to the extent that they form a group at a position several positions below the focal point.

The gas flow described above forms what is called the eye of a typhoon, the center of which has a lower pressure near the focal point than the surrounding area, and the melt is sucked in from the melt nozzle.

Furthermore, the filament is continuously pulled out from the tip of the cone by the centrifugal force obtained by rotating the filament.

Further, even if the gas flows enter the second region and collide at a point a number of points away from the focal point, the turbulence caused by the collision will not disturb the formation of the cone because it is separated by light from the cone.

The gas flows colliding near the above position become a group,
The filaments that have entered the high-density energy part of the gas flow at the top of the second region are further stretched by the resultant force, so that thin fibers can be obtained more effectively.

On the other hand, if the gas flows collide too strongly near the focal point, the pressure at the center near the focal point will be less likely to be lower than the surrounding area, and the force to draw out the melt from the melt nozzle will weaken and become unstable, causing the filament to become continuous. The cone does not form a stable shape.

Increasing the diameter of the total gas flow at the focal point so that the gas streams do not collide near the focal point reduces the rotational speed imparted to the filament at the beginning of the second zone.

That is, the zero rotational speed of the filament is small and the centrifugal force is therefore weak, so the force for drawing out the filament from the tip of the cone is weak, the amount of melt flowing out at zero is small, and the filament cannot be made very thin.

This phenomenon tends to occur when the spread angle (diffusion angle) of the gas flow is narrow; therefore, the gas flow ejected from the gas flow nozzle does not expand immediately, and retains a portion of the high-density energy with a small diffusion angle for a long time. It is suitable for fiber production by the swirling gas jet method.

The inventors have found that these properties are extremely closely related to the shape of the gas flow nozzle, and are particularly related to the ratio of the effective diameter of the nozzle to the nozzle length.

The present invention provides an apparatus for producing fibers of a heat-softening material by applying a swirling gas flow to a molten columnar flow of a heat-softening material to make the heat-softening material thinner. A gas flow nozzle that ejects a gas flow only in a single direction, characterized in that the length l of the gas flow nozzle is 5 times or more the effective diameter α of the nozzle. It is a device.

The effective diameter α of the nozzle here is expressed by the following equation.

However, A - Nozzle cross-sectional area of a cross section perpendicular to the gas flow direction within the gas flow nozzle.

S - Nozzle peripheral length in a cross section perpendicular to the gas flow direction within the gas flow nozzle.

Further, the nozzle length refers to the shortest length from the gas inlet to the outlet of the nozzle, measured in the direction of gas flow within the nozzle.

When the ratio of the effective diameter of the gas flow nozzle to the nozzle length is less than 5 times, the diffusion angle of the gas flow ejected from the nozzle becomes large, and the gas flow ejected from three or more nozzles surrounding the melt becomes a focal point. It becomes easier to collide strongly near the position,
This results in the above drawbacks.

By setting the ratio of the effective diameter of the gas flow nozzle to the nozzle length to be 5 times or more as in the present invention, it is possible to reduce the diffusion angle of the gas flow ejected from the nozzle, thereby obtaining a stable cone and a strong cone. Since turning power can now be obtained, it has become possible to finely refine the material efficiently.

Although the upper limit of the ratio of the effective diameter of the gas flow nozzle to the nozzle length is not particularly limited, increasing this value too much increases the pressure drop of the gas and is accompanied by difficulties in construction, so it is preferably less than 20. is kept below 10.

Note that it is difficult to make the effective diameter of the gas flow nozzle smaller than 0.051n11L due to limitations in machining accuracy.

Further, if the diameter becomes too large, the amount of gas used increases and is not economical, so it is preferable that the diameter is 3 or less.

Example Using a glass fiber unit as shown in Figures 1 and 2, tests were carried out by changing the diameter and length of the gas flow nozzle 1. The results are shown in the following table, except that the cross section of the gas flow nozzle The shape is circular.

The glass temperature at the cone is 12000 C (50 poise) and the glass melt nozzle inner diameter is 2 mm.

The angle between the central axis of the gas flow nozzle and the central axis of the glass melting cylinder is 45°, and the distance between the gas flow nozzle outlet and the central axis of the glass melting cylinder is approximately 2.0 mm. Total gas flow diameter is 0.7-1.7
It is mm.

The gauge pressure of the high pressure air supplied to the gas flow nozzle is approximately 5 kg/cyit.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional view of a fiberizing unit in which the melt nozzle and the gas flow nozzle are made of separate bodies, and FIG. 2 is a bottom view as seen from OJ A-A in FIG. 1. It is a diagram. 1... Gas flow nozzle, 2... Melt nozzle, 3... Molten cylindrical flow, 4... Cone, 8... Filament, 5... Gas flow, 13... Gas flow Φ High density energy part.

Claims (1)

[Claims] 1. In an apparatus for producing fibers of a thermosoftening material by applying a swirling gas flow to a molten cylindrical flow to thin the thermosoftening material, three or more fibers surrounding the molten cylindrical flow are used. 1. An apparatus for producing fibers of a heat-softening substance, characterized in that a gas flow nozzle for ejecting a gas flow in only one direction has a length that is at least five times the effective diameter of the nozzle.