JPH0544105A - Method for melt spinning - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent deterioration of the polymer, to restrict the discharge area of the polymer, and to easily attach and detach the die to improve operability. [Structure] A pack body 1 having a base 2 attached to a lower surface is inserted into a spin block 7 and fixed by a bolt 8. An induction coil 13 is attached around the side surface of the pack body 1 with a gap 12 therebetween. When a low-frequency current is applied to the induction coil 13, deterioration of the polymer is suppressed due to induction heating of the cap body together with the pack body 1, and the base 2 vibrates at a low frequency, so that the yarn separation from the base 2 is improved. The pack body 1 can be easily attached to and detached from the spin block 7 by the bolt 8, and the induction coil 13 does not limit the discharge area of the polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for melt spinning a polymer such as polyester and polyamide, and more particularly to a method for performing melt spinning while induction heating a melt spinning die attached to a pack body.

[0002]

2. Description of the Related Art Conventionally, as a melt spinning method of this type, there is one disclosed in, for example, Japanese Patent Laid-Open No. 62-177207. In this melt spinning method, an induction coil is provided in the vicinity of the lower surface of a spinneret for melt spinning, and an induction current is generated in the spinneret to heat the spinneret while performing melt spinning. According to this method, since only the spinneret can be selectively heated, high-speed spinning can be performed without causing deterioration of the polymer, and energy loss is reduced, which is advantageous in that it is economical. is there.

Further, Japanese Patent Laid-Open No. 2-112403 discloses a spinning pack having a pack body incorporating a filter body, a spinneret, etc., wherein at least one slit is provided on the side surface of the pack body, and the slit is provided in the slit. A spinning pack having a heat insulating plate inserted therein is disclosed. This spinning pack is intended to prevent polymer deterioration by thermally dividing the pack body in the vertical direction by the heat insulating plate so that the influence of the temperature of the spinneret does not reach the upper part of the pack. Is.

[0004]

However, the above-mentioned conventional example has the following problems. That is,
In the melt spinning method described in JP-A-62-177207, since the induction coil is installed on the lower surface of the spinneret, when the discharge area of the polymer is widened, the discharged filament comes into contact with the induction coil. However, there is an inconvenience that the discharge area of 1 must be set narrow.

In addition, when cleaning the mouthpiece discharge surface, the induction coil is an obstacle to cleaning, and when the pack body is attached and detached from below the spin block, the induction coil must be attached and detached, resulting in poor operability. There is also a problem.

On the other hand, in the spinning pack described in Japanese Patent Laid-Open No. 2-112403, the heating method of the spinning pack is convection or radiant heating. The temperature tends to be the same, and the effect of preventing deterioration of the polymer decreases. There is also a problem that the thread is not easily separated from the mouthpiece.

The present invention has been made in view of the above circumstances, and it is possible to prevent deterioration of the polymer for high-speed yarn production, and to set a wide discharge area of the polymer. An object is to provide a melt spinning method with good operability.

[0008]

The present invention has the following constitution in order to achieve such an object. That is, in the invention according to claim 1, an induction coil is provided around the side surface of the pack body to which the spinneret for melt spinning is attached with a gap, and an induction current is generated in at least the pack body, Melt spinning is performed while heating the pack body.

The invention described in claim 2 is the same as claim 1
In the melt-spinning method described in (1), a low-frequency current is passed through the induction coil to perform melt-spinning.

Further, the invention according to claim 3 is the melt spinning method according to claim 1, wherein the temperature of the portion of the pack body facing the induction coil is set to be lower than the temperature of the polymer induction portion of the pack body. Also above 10 ℃ 150
Melt spinning is performed at a high temperature in the range of ℃ or below. Here, the temperature of the portion of the pack body facing the induction coil means the temperature of the outer circumferential surface of the pack body and the position of the induction coil facing the well-known temperature such as a thermocouple or a resistance temperature detector. The value measured by a measuring instrument. Further, the temperature of the polymer introducing portion of the pack body refers to a value obtained by measuring the temperature of the outer peripheral surface of the pack body and in the vicinity of the polymer introducing portion with the above measuring device.

[0011]

According to the invention described in claim 1, since the induction coil is provided around the side surface of the pack body, the discharge area of the polymer is not restricted by the induction coil, and when the pack body is removed, Since the induction coil does not get in the way, the operability is improved. Also, the pack body is heated by the induction coil provided with a gap around the side surface of the pack body to which the spinneret for melt spinning is attached, and the spinneret part is more effective due to heat conduction from the pack body. Is heated to. Therefore, the polymer melted by the melter (not shown) enters the pack body from the polymer pipe of the spin block and reaches the spinneret, but the part of the pack body and spinneret facing the induction coil is heated to the temperature required for spinnability. Therefore, the polymer is not unnecessarily heated and deteriorated by the time it is introduced from the melter to the die, and the energy loss is reduced. Further, by arranging the induction coil around the lower side surface of the pack body, in particular, at a position including the extension surface of the upper surface or the lower surface of the mouthpiece attached to the pack body, the above-mentioned effect becomes large. Further, since induction heating is used, the temperature rising time at the time of heating is short, so that the temperature control response is good, the polymer viscosity can be controlled with good response, and the operability is further improved.

According to the second aspect of the present invention, since the low frequency current is passed through the induction coil, the pack body vibrates at a low frequency and the cap itself vibrates, so that the polymer (thread) is separated from the cap surface. The effect is large, and the vibrating of the die itself also has the effect of reducing the amount of dirt attached around the discharge holes. In addition, the penetration depth of the induced current generated in the pack body is deeper than that in the case where a high-frequency current is applied to the induction coil, and the induced current is generated not only in the pack body but also in the mouthpiece part. It also has the effect of reducing the temperature difference. Generally, the penetration depth δ of the induced current is inversely proportional to the square root of the power supply frequency f, and the material of the non-heated body is 1
In the case of 8-8 stainless steel, δ≈60Hz at room temperature
It is 57 mm.

According to the third aspect of the invention, the temperature of the induction portion of the pack body facing the induction coil is 10 ° C. or more and 150 ° C. or less as compared with the temperature of the polymer introducing portion of the pack body, in other words, the temperature of the spin block. By increasing in the range of, effectively heat the polymer sent at low temperature,
The spinnability required for spinning can be provided. Where 1
The reason for setting the temperature to 0 ° C or higher is that in order to prevent thermal deterioration of the polymer, it is necessary to bring the polymer to the vicinity of the spinneret at a low temperature of 10 ° C or higher with respect to the spinning temperature, and the temperature difference of substantially 10 ° C or higher. This is because the polymer will not be heated effectively without the presence of this. The reason for setting the temperature to 150 ° C. or less is that, particularly in the case of a polymer that is severely deteriorated, it is desirable to feed the liquid at a temperature as low as possible and to heat it to a temperature at which the necessary spinnability is obtained immediately before the spinneret. .. Generally, the melt temperature of the polymer to be melt-spun is about 180 to 240 ° C, while the spinning temperature is about 250 to 320 ° C. Therefore, it is not necessary to make the temperature of the induction coil facing portion higher than 150 ° C. as compared with the polymer introduction portion of the pack body.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A melt spinning method according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a peripheral portion of a melt spinning die.

In the figure, reference numeral 1 is a pack body having a spinneret 2 for melt spinning attached to its lower surface, and is composed of members 4 to 6 and 16 shown by solid line hatching in the figure, which are shown in FIG. It is tightened with a bolt (not shown) and integrated. In the pack body 1, at least the member 6 that supports the member 6 and the base 2 is made of a material that generates an induced current, that is, metal, such as stainless steel. The base 2 is also preferably made of a material that generates an induced current.

The pack body 1 is inserted into an opening formed in the spin block 7 and having a diameter slightly larger than that of the pack body 1 from below or above, and is detachably fixed by a bolt 8 to prevent heat radiation on the upper surface thereof. A heat insulating member 9 is arranged for this purpose.

The spin block 7 and the members 4 and 5 in the pack body 1 are formed with a flow path 10 for introducing the molten polymer, and the molten polymer is provided in the void formed on the lower surface of the member 5. A filter 11 is provided to remove foreign matter inside. The filter 11 is composed of sand or a porous metal body and a wire mesh under it. The molten polymer that has passed through the filter 11 is supplied to the base 2 through a plurality of branch channels provided in the member 6.

The spin block 7 is, as shown in FIG.
The temperature is detected by a temperature measuring sensor 17 provided at a position as close as possible to the molten polymer introducing portion B of the pack body 1, and a known heating medium is enclosed by a controller 18 so that the temperature reaches a preset predetermined temperature. The heating box or the electric heater 19 is controlled and maintained at the temperature required for feeding the molten polymer into the flow path 10. The temperature of the molten polymer introducing portion B of the member 4 of the pack body 1 pressed against the spin block 7 by the bolt 8 is also maintained at the same temperature as the spin block 7.

On the other hand, an annular induction coil 13 is arranged below the pack body 1 with a slight gap 12 (for example, about 1 to 2 mm). This induction coil 13
By interposing the magnetic shield body 15 formed of, for example, a silicon steel plate between the member supporting the same and the member 14 supporting the same, members other than the member facing the inner surface of the induction coil 13 are prevented from being heated as much as possible. There is. Specifically, as shown in FIG. 3, a temperature measuring sensor 20 is attached to a portion A of the pack body 1 facing the induction coil 13, and a current flowing through the induction coil 13 is supplied to the controller 18 based on the detection signal. The temperature is controlled to 10 ° C. or more and 150 ° C. or less as compared with the temperature of the preset temperature, that is, the temperature of the molten polymer introducing portion B, in other words, the spin block 7.

The temperature measuring sensor 20 does not necessarily have to be directly attached to the portion A, but may be attached to the inner surface of the induction coil 13 and the temperature of the gap 12 may be detected to control the current flowing through the induction coil 13. This is preferable because it is not necessary to attach and detach the temperature measuring sensor 20 when attaching and detaching the pack body 1. In that case, the temperature of the gap 12 (ambient temperature) is always lower than the temperature of the portion A, and therefore the set temperature needs to be set low. For example, in order to control the temperature of the portion A to 300 ° C., it is necessary to control the temperature of the gap 12 to be about 290 ° C. The temperature difference between the A portion and the gap 12 changes depending on the temperature of the spin block 7 and the temperature difference between the A portion and the like, but usually does not exceed 30 ° C. Further, it is also possible to control a plurality of induction coils simultaneously by one temperature control device based on the signals of the temperature measuring sensor attached at one place. The gap in the present invention is preferably uniform over the entire circumference of the pack body 1, but may be biased to one side as long as the pack body 1 can vibrate.

Since the gap 12 is interposed between the pack body 1 and the induction coil 13 arranged around the side surface of the pack body 1 as described above, by loosening the bolt 8 screwed to the spin block 7, The pack body 1 and the base 2 can be easily separated from the spin block 7 as a unit, and the pack body 1 and the base 2 can be exchanged. Further, since the induction coil 13 is not provided on the lower surface of the pack body 1, it is possible to easily clean the base surface from below.

The frequency of the current flowing through the induction coil 13 is not particularly limited, but in order to improve the separation of the polymer discharged from the die 2, and to increase the penetration depth of the induction current,
From the point of reducing the temperature difference in the radial direction, 30 to 200H
A low frequency current of z is preferred. Particularly, from the viewpoint of economy, the commercial frequency (60 Hz or 50 Hz) is more preferable.

When an alternating current flows through the induction coil 13, an induced current flows through the pack body 1 facing the alternating current, and the base 2
The lower part of the pack body 1 to which is attached is partially heated. Further, when a low-frequency current flows through the induction coil 13, the pack body 1, and thus the mouthpiece 2, vibrates at a low frequency, so that the yarn discharged from the polymer discharged from the mouthpiece 2 becomes good.

FIG. 2 shows a pack body 1 having a diameter of 240 mm.
Shows the temperature rise characteristics of the base 2 when induction heating is carried out at a low frequency (commercial frequency) with 2.13 kW of electric power.
As is clear from FIG. 2, a typical die temperature of 270-2
It takes about 120 minutes to reach 80 ° C. At this time, it was confirmed that the temperature rise in the portion other than the die portion was slight and the deterioration of the molten polymer could be suppressed as much as possible.

FIG. 4 is a schematic sectional view showing an example in which the pack body 1 shown in FIG. 1 has a different shape. In the figure,
Reference symbol P indicates an extended surface of the upper surface of the base 2, reference symbol Q indicates an extended surface of the lower surface of the base 2, and other reference numerals are the same as in FIG. The difference from FIG. 1 is that the mouthpiece support member 16 wraps the entire pack body. The pack body 1 according to the present invention may be changed in shape as described above, and if the pack body 1 is provided, for example, a filter is omitted, or between the polymer receiving member 4 and the base 2. A known static mixer for mixing the polymers may be provided by forming a passage in which the polymer flow is divided and merged repeatedly. The position of the induction coil 13 including the magnetic shield body 15 in the present invention is preferably arranged at a position including at least one of the extension planes P and Q (in FIG. 4, the extension plane P is included). ..

In order to confirm the effect of the present invention, spinning was performed under the following conditions. A polyethylene phthalate chip was melt-extruded with an extruder (not shown) having a screw shaft diameter of 40 mm, guided to the spin block 7 and the pack body 1 while being weighed with a gear pump, and spun from the die 2. As the die 2, one having a hole diameter of 0.4 mm and a number of holes of 120 was used. As the temperature of the pack body 1, the temperature measuring resistor 20 is provided on the outer surface of the member 6 to measure the temperature, and the temperature is 19
The current flowing through the induction coil 13 was controlled so as to be 5 ° C. On the other hand, the temperature of the spin block 7 depends on the resistance temperature detector 17
Is provided on the outer peripheral surface of the member 4 and in the vicinity of the flow path 10, and the temperature thereof is measured so that the respective levels shown in the following table, that is, 195 ° C., 180 ° C., and 175 ° C. The electric heater 19 was controlled.

As shown in the following table, the results obtained in this way were the effects of suppressing the reduction in intrinsic viscosity (IV) in Examples 1 and 2, that is, the effect of suppressing deterioration of the spun polymer. However, Spin Block 7 and Pack Body 1
This effect was not obtained in the comparative example in which there was no difference in temperature.

[0028]

[Table 1]

[0029]

As is apparent from the above description, the present invention has the following effects. That is, according to the invention described in claim 1, since the pack body is partially induction-heated by the induction coil provided on the side surface of the pack body to which the spinneret for melt spinning is attached with a gap therebetween,
The molten polymer up to the die is unnecessarily heated,
It does not deteriorate, and the temperature of the lower surface of the die is not lowered by the air flow on the lower surface of the die, so that the stable die temperature is always maintained. Further, since the induction coil does not limit the polymer discharge area and the induction coil does not interfere, the pack body can be removed from below, and the mouthpiece can be cleaned with the pack body attached. Since it can be easily performed, operability is improved. Furthermore, since the heating time is short, the responsiveness of temperature control is fast (the die temperature from 290 ° C to 300 ° C).
When the temperature is raised to 0 ° C., the induction heating is faster in 60 minutes by the electric heating and 15 minutes by the induction heating.) Therefore, the response of the control of the polymer viscosity is good, and the operability is further improved.

Further, according to the second aspect of the present invention, since the low frequency current is passed through the induction coil, the low frequency vibration of the cap integrally with the pack body results in good yarn separation from the cap. Further, the adhesion of dirt around the die discharge is reduced, the penetration depth of the induced current is increased, the temperature difference in the radial direction of the die is reduced, and the operability can be further improved.

Further, according to the invention of claim 3, the temperature of the induction coil facing portion A is locally raised to 10 ° C. or more and 150 ° C. or less as compared with the temperature of the molten polymer introducing portion B of the pack body. By effectively heating the polymer fed at a low temperature and imparting the spinnability required for spinning, it is possible to stably spin a yarn having no deterioration in physical properties such as a decrease in intrinsic viscosity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a spinneret portion of a melt spinning apparatus according to an embodiment.

FIG. 2 is a diagram showing a temperature rise characteristic of a die portion due to low frequency induction heating.

3 is a cross-sectional view showing a temperature control unit of the melt spinning apparatus shown in FIG.

FIG. 4 is a cross-sectional view of the spinneret portion of the melt spinning device when the shape of the pack body is different from that in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pack body 2 ... Base 7 ... Spin block 12 ... Gap 13 ... Induction coil 16 ... Base support member

Claims (3)

[Claims] 1. An induction coil is provided around a side surface of a pack body to which a melt-spinning die is attached through a gap, and an induction current is generated in at least the pack body to heat the pack body. And a melt spinning method characterized by performing melt spinning. 2. The melt spinning method according to claim 1, wherein a low frequency current is passed through the induction coil to perform melt spinning. 3. The melt spinning method according to claim 1, wherein the temperature of the portion of the pack body facing the induction coil is 10 ° C. or more and 150 ° C. or less than the temperature of the polymer induction portion of the pack body. A melt spinning method in which melt spinning is performed at a high range.