JPS62104922A - Centrifugal spinning unit for pitch fiber - Google Patents

Abstract

PURPOSE:Air-blowing nozzles are opened on both sides of the outer periphery of a rotary nozzle and air interceptors are set both above and beneath the outer periphery in a specific state to increase the air flow from the nozzle over the original speed whereby pitch fibers of good quality are obtained. CONSTITUTION:In the centrifugal spinning unit having a rotary spinning nozzle 1 in which the direction of the rotary shaft is vertical, while the fiber-jetting direction is horizontal, air-blowing nozzles or slits, 2, 3 are set both above and beneath the outer periphery of the rotary spinning nozzle 1 and air-flow interceptors 4, 5 are set both above and beneath the outer periphery so that the distance between the interceptors becomes narrow as they depart from the periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a centrifugal spinning device. More specifically, the present invention relates to a pitch-based carbon fiber centrifugal spinning device having excellent spinning performance.

(Prior art and problems) Conventionally, in the process of centrifugal spinning of pitch-based carbon fibers, the air flow around the rotating nozzle was insufficiently controlled, so the diameter of the fibers was not uniform in the length direction, i.e. A pitch-based carbon fiber with excellent strength could not be obtained due to the remarkable necking phenomenon.

For example, as seen in Japanese Patent Laid-Open No. 60-167908, hollow rings are provided above and below the outer periphery of a rotating nozzle, and slits that are inclined toward the outside in the radial direction of the rotating nozzle are arranged on opposing surfaces of the hollow rings. Although a centrifugal spinning device has been proposed, since the spacing between the upper and lower hollow rings is constant, the speed of the air decreases toward the outside, making it difficult to obtain m-fibers with a uniform diameter in the length direction. Met.

It is also possible to take this idea further and increase the number of slits concentrically to increase the amount of air radially outward from the rotating nozzle, but this would require a large amount of pressurized air. In addition, it was difficult to obtain ili fibers having a uniform diameter because the air flow was easily disturbed and the spun 41 fibers vibrated.

(Means for Solving the Problems) In view of the above circumstances, the inventors of the present invention have conducted various studies and found that a centrifugal spinning device using pitch-based carbon 41 has excellent spinning performance that could not be obtained with conventional techniques. He came to invent this.

That is, in a centrifugal spinning device in which the rotation axis of the rotating nozzle is vertical and the direction of discharge of the liquid is horizontal, air blowing nozzles or slits are provided above and below the outer periphery of the rotating nozzle, and air blocking nozzles or slits are provided above and below the outer periphery of the rotating nozzle. A pitch-based charcoal T4 fiber characterized in that the air flow velocity from the air blowing nozzle is constant or accelerated by providing a plate and decreasing the interval between the upper and lower air blocking plates toward the outer periphery. This led to the invention of a centrifugal spinning device.

(Function) If the centrifugal spinning device for pitch-based carbon and IS fibers according to the present invention is used, the flow velocity distribution of the air around the outer periphery of the rotating nozzle becomes constant or accelerates toward the outer periphery. Spinning is carried out continuously and smoothly, resulting in l1il'lI with a uniform yarn diameter in the length direction, that is, a raw yarn without necking phenomenon, and when this is further advanced to an infusible process and a carbonization process, high strength is obtained. 41 carbon fibers are obtained.

Let us explain these mechanisms of action in more detail. If there are air blowing nozzles or slits above and below the outer periphery of a rotating nozzle, and if there are air blocking plates above and below the outer periphery, and the interval between the upper and lower air blocking plates is constant, the flow velocity of air from the air blowing nozzles or slits is Since the volume increases toward the outside, the speed is multiplied by the value r/R (ro: outer radius of the air blowing nozzle or slit, R: arbitrary radius through which the air passes, always ``. < R). For example, it can be seen that the air flow velocity at a point located twice the radius of the air blowing nozzle or slit is 172 times the initial velocity.

Therefore, the fibers immediately after spinning become sag in the middle and have a yarn diameter of 1lIIf1 that is not uniform in the length direction, that is, S fibers with a lot of necking.

However, in the case of the l1ff according to the present invention, the interval between the upper and lower air shielding plates is designed to become smaller toward the outer periphery, so the above-mentioned decrease in air velocity does not occur, so that fibers with good straightness can be used. is obtained, resulting in M& fiber with a uniform diameter in the length direction, resulting in high-strength charcoal 'f4!
Connects to a fiber.

(Example) Since the centrifugal spinning apparatus of the present invention is effective for spinning Mesof I-Z petroleum pitch, this example will be described in detail below, but the present invention is not limited thereto.

(Example-1) A rotating nozzle 1 (radius: 100 pieces,
Nozzle diameter: 20, 3mm x Nozzle length: 1.2run, number of nozzle holes: 100 holes), with an inner diameter of 210mm and an outer diameter of 230. air blowing nozzles 2 and 3 (number of nozzle holes; 200 holes both above and below), and furthermore, air blocking plates 4 and Using a centrifugal spinning device for pitch-based carbon EUI, the softening temperature was 280°C.
℃ mesophase petroleum pitch as raw material, the temperature of the rotating nozzle was controlled at 405℃, and the rotation speed was 4000 rpm.
Centrifugal spinning was carried out under the condition that the air flow rate from the air blowing nozzle was 50 i/s.

The obtained yarn is oxidized in air to make it infusible,
Furthermore, when we measured the strength of carbon fiber produced by carbonization firing at 1000°C in a nitrogen atmosphere, it was found to be 13.1 Ton.
/c11"te<F).

(Example-2) A rotating nozzle 1 (radius, 100 mm,
Nozzle diameter: 0.3zgx nozzle length: 1°2mm, number of nozzle holes: 100 holes), with an inner diameter of 210mm above and below the outer circumference,
Air blowing nozzles 2 and 3 (number of nozzle holes: 200 holes) with an outer diameter of 230M, and an inner diameter of 2 above and below the outer diameter.
A pitch-based carbon fiber centrifugal spinning device consisting of air shielding plates 4 and 5 that form part of two straight lines with a diameter of 30# and an outer diameter of 390 m and whose cross-sectional views approach each other was used to produce a pitch-based carbon fiber with a softening temperature of 270°C.
Using the mesophase petroleum pitch of
Centrifugal spinning was carried out under the condition that the air flow rate from the air blowing nozzle was 40 n/s.

The obtained yarn is oxidized in air to make it infusible,
When the strength of carbon fiber produced by carbonization firing at 1000°C in a rough nitrogen atmosphere was measured, it was found to be 12.8Ton.
/C112T-1) Tsuta.

(Comparative Example-1) Rotating nozzle 1 (radius; in 100 order,
Nozzle diameter: 0.3g x nozzle length: 1.2M, number of nozzle holes: 100 holes), with an inner diameter of 210mm above and below the outer circumference,
Air blowing nozzles 2 and 3 (number of nozzle holes, 200 holes) with an outer diameter of 230s, and an inner diameter of 2 above and below the outside.
3011111N Outer diameter: 390 By using a pitch-based carbon fiber centrifugal spinning device consisting of punching plates 8 and 9 with numerous holes forming part of two straight lines whose cross-sectional views are parallel to each other, the softening temperature is 270. Centrifugal spinning was carried out using mesophase petroleum pitch at 390° C. as a raw material, controlling the temperature of the rotating nozzle at 390° C., rotating at 3800 rpm, and air flow rate from the air blowing nozzle at 40 Il/s.

The obtained yarn is oxidized in air to make it infusible,
Furthermore, when we measured the strength of the carbon fiber produced by carbonization firing at 1000°C in a nitrogen atmosphere, it was found to be 8.8Ton/
cn2 teatuta.

As is clear from the examples according to the present invention and comparative examples,
By using the pitch-based carbon a-fiber centrifugal spinning apparatus of the present invention, it is possible to produce high-strength carbon 411 miscellaneous material.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of the main parts of a centrifugal spinning apparatus for pitch-based carbon fibers according to the present invention, and FIG. 3 is a cross-sectional view of the main parts of a centrifugal spinning apparatus for pitch-based carbon II fibers according to the prior art. be. 1... Rotating nozzle 2... Air blowing nozzle or slit (top) 3
・-・Air blowing nozzle or slit (bottom) 4・
... Air blocking plate (top) 5... Air blocking plate (bottom) 6... Rectifying layer 7... Hyperbola 8... Punching plate (top) 9... Punching plate (bottom) (other 1 name) Figure 3 t

Claims (1)

[Claims] In a centrifugal spinning device in which the rotation axis of the rotating nozzle is vertical and the fiber discharge direction is horizontal, air blowing nozzles or slits are provided above and below the outer periphery of the rotating nozzle, and air blocking plates are further provided above and below the outer periphery. The pitch-based carbon fiber is characterized in that the interval between the upper and lower air blocking plates is reduced toward the outer periphery, so that the flow velocity of air from the air blowing nozzle is constant or accelerated toward the outer periphery. centrifugal spinning equipment.