JPS5854098B2 - Equipment for producing fibers made from thermosoftening substances - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for producing fibers from a heat-softening material by applying a swirling gas jet to the material.

In recent years, a so-called swirling gas jet method has been proposed as a method for thinning thermosoftening materials such as glass into fibers.

(Japanese Patent Application No. 101618, filed on August 20, 1975 - Japanese Patent Application Laid-open No. 125113) The present invention is based on a gas flow having a component in the tangential direction of the outer periphery of the cross section in the direction of travel in the molten cylindrical underground flow of a heat-softening substance. Conventional blow method (flame method) centrifugal method involves rotating the molten material at high speed while keeping it in contact with the molten material to prevent it from moving in the lateral direction, and drawing out the narrowed filamentous material using centrifugal force It has become clear that this method has significant advantages in terms of production efficiency and product quality compared to other methods.

In more detail, the swirling gas jet method consists of continuously flowing out a melt of a heat-softening material, and injecting the melt into the melt in a first area along the progress of the flowing melt. A gas flow having a component in the tangential direction of the outer periphery of the cross section is brought into contact with the melt to prevent it from displacing in the lateral force direction, thereby confining the melt in one limited position. consisting of one rotation about the central axis in the direction of travel, so that a second zone following from said first zone along the melt advance is mainly due to the inertia of said rotational force. The centrifugal force caused by the rotation causes the melt to fly out in one lateral force direction, and the flying direction is the circumferential direction as seen from the central axis, and the same direction as the rotation is made to rotate the melt one turn to remove heat from the melt. This is a method for producing fibers of a heat-softening substance, which is characterized by continuously drawing out fibers of a softening substance.

And more preferably, the melt of the thermosoftening substance is continuously discharged from the melt nozzle outlet with a cross-sectional diameter of between 0.5 and 10, and the progress of the discharged melt is 1.
A gas flow having a component tangential to the outer circumference of the cross-section of the melt in a first region along the melt and a component approaching the central axis of the melt along the progress of the melt is directed to the tip of the melt nozzle. , so that the distance between the center axis of the advancing melt and the position where the gas flow approaches the closest is 0.2 to 10 times the inner diameter of the melt nozzle, and the melt is moved laterally. The method consists of rotating the melt about the central axis while confining the melt in a limited position and forming a tapered conical shape by making contact so as to prevent the melt from being displaced; In a second zone 1 following the melt progress from the first zone, the melt is moved laterally from the tapered tip of the conical shape mainly due to the centrifugal force due to the rotation due to the inertia of the rotational force. Make it pop out in one direction of force, and rotate it one turn with the popping direction 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 by continuously drawing fibers of a heat-softening material from a melt.

The inventor discovered that, in the swirling gas jet method, the effective pore diameter of the melt outlet that forms a molten cylindrical underground flow has a significant effect on the quality and production efficiency of the fibrous material produced by the method, and developed the present device. The gist of the present invention is to provide an apparatus 1 for producing fibers of a thermosoftening material by applying a swirling gas jet to a molten cylindrical underground flow of a thermosoftening material to thin the thermosoftening material. This apparatus is characterized in that the effective pore diameter of the outlet for the melt of the thermosoftening material is 0.5 mπ to 2.5 mπ.

In the swirling gas jet method, it is advantageous to use three or more high-speed gas jet streams to act on the molten cylindrical flow so that the molten cylindrical underflow is swirled and stretched at high speed.

In this case, the high-velocity jet stream approaches the molten columnar stream E in the first zone 1 so as to confine the melt.
A cone is formed, and in the second section following the cone, a filament is stretched out and rotated at high speed.

Here, in order to draw the thread more efficiently, it is necessary to rotate the conical tip at a higher speed.

The rotational speed n (times/5ec) of the tip of the cone is n=k
It is expressed as v/2πr0.

However, here, V is the component of the flow velocity of the high-speed gas flow in the tangential direction of the outer circumference of the molten cylindrical underground flow cross section, r.

is the average value (aperture radius) of the distance between the center of the molten cylindrical underflow and each gas jet flow center at one place where the gas jet approaches the molten cylindrical underflow (referred to as the focal point), and k is the slip coefficient.

Therefore, if you want to increase the rotation speed n, you will have to increase r by increasing 2v.

It is advantageous to make it as small as possible.

Here, the gas flow velocity tangential component V is almost constant near the sound velocity of 1, so r.

must be made smaller and k larger.

There is a limit to r□ because if it is made too small, the gas streams will collide with each other, causing turbulence and making it impossible to form a stable cone.

Therefore, it is necessary to make the slip coefficient k as large as possible9).

The slip coefficient is determined by the ratio of the velocity of the filamentous melt to the gas flow velocity.Thus, when the melt swirls, the larger the force that tries to prevent the swirl, the smaller the thick diameter k.

In actual practice, k is approximately 0.01 to 0.5 in one operation range, which is quite small, so increasing the value of k has a large effect.

In order to increase k when r02V etc. are constant, it is considered effective to lower the viscosity of the melt or to reduce the diameter of the cylindrical underground flow.

Therefore, the inventors tried to lower only the viscosity of the melt by setting the diameter of the cylindrical underflow to a value larger than 2.5 degrees, for example, to a constant value of 3.0 mm, but in this case, the diameter of the cylindrical underflow was set to a constant value of 3.0 mm. The torsional resistance caused by swirling 1 is a problem (because the viscosity of the molten material is low, the tip of the molten material is blown away by the gas flow 1, resulting in a large amount of unfiberized beads and flakes, causing fibers to form). It turned out that there was a problem with this.

On the other hand, the diameter of the cylindrical underground flow should be 2.5 mm or less, preferably 2 mm.
(Thus, firstly, the torsional resistance due to the swirling of the columnar underground flow becomes extremely small, and secondly, the phenomenon of splitting and blowing away of the gas airflow occurs.) The viscosity of the melt is about 3 [to 50 poise] 1
It has been found that the effects are significantly enhanced, as the twisting resistance due to the swirling of the cylindrical underground flow is further reduced because it can be lowered even further.

Since it is the outflow nozzle of the melt that forms the cylindrical underground flow, the effective hole diameter of the outflow nozzle (4 times the cross-sectional area of the hole divided by the circumference) should be 2.5 degrees, preferably 2 mrn or less. Therefore, the cylindrical underground flow can be rubbed once in this way.

However, reducing the effective hole diameter of the melt outlet nozzle means that the flow rate of the melt flowing out from it is limited, which means that the amount of fiber produced per unit time of one fiber forming unit is limited. do.

Therefore, the effective hole diameter of the melt outflow nozzle is too small.
＼It is not effective to shorten it, and in this sense, it is 0.5 mm.
It is necessary to do more than that.

Of course, it is possible to obtain high quality fibers even with an effective pore diameter of 0.5 mm or less.

Embodiment 1 of the present invention In order to increase the amount of melt flowing out, the horizontal depth of the melt is increased and a head is applied or pressure is applied, and the tip of the outflow nozzle is 25Cr.
It is preferable to rub so as to obtain a pressure of 40 CrILaq or more, preferably 40 CrILaq or more.

It is preferable that the temperature of the heat-softening material just before it starts swirling by the gas jet is maintained at a temperature so that its viscosity is 10 to 200 poise, more preferably 30 to 100 poise.

Next, the present invention will be explained using examples.

EXAMPLE An experiment was carried out using a fiber forming unit of the shape shown in Fig. 1. Table 1
We obtained the following results.

In Figures 1 and 2, the molten glass is in the pot 8.
The cone 4 is formed by a high-speed air jet 61 ejected from the air jet nozzle 1, and is then finely divided into fibers 5.

The jet 6 comes closest to the central axis 1 of the cone 4 at a position about two peaks below the outlet 3.

There are three air jet nozzles each having a circular cross-sectional diameter of about 1.0 degrees and making an angle of 45 degrees with the horizontal plane, and they form an angle of 120 degrees when projected onto the horizontal plane.

The air outlet is not in contact with the molten glass outlet, but is located as close as possible.

In Table 1, the test was conducted by adjusting the depth of the tank so that the glass flow rate was 1 kg per hour.

Is the air tokg/cI? At L gauge pressure, the glass has a viscosity of approximately 50 poise at the outlet.

Note that when the glass outlet diameter was 0.5 mm, the glass flow rate could not be set to L kg/hr.

As shown in Table 1, when the glass outlet diameter is between 1 and 3, the proportion of unfibered material, that is, the ratio of the amount of unfibered material to the total amount of fiberized material and non-fibered material produced per unit time is 50φ1. The glass outlet diameter is 2.5 mm.
It can be seen that the proportion of non-fiberized material decreases and the fiber diameter decreases with each passing step.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a detailed explanatory diagram of the present invention, and FIG. 2 is a bottom view seen from the direction AA in FIG. 1. 8...Thermosoftening substance, 5...Fiber, 3
・・・・・・Outlet of melted material of thermoplastic substance.

Claims (1)

[Claims] 1. A molten cylindrical underground flow of a molten thermosoftening material.1 A device for producing fibers of a thermosoftening material by applying a swirling gas jet to thin the thermosoftening material. An apparatus for producing fibers of a heat-softening substance, characterized in that the effective pore diameter of the outlet is 0.5 to 2.5 mm.