JP2894049B2 - Melt spinning method - Google Patents

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 or polyamide, and more particularly to a method for performing melt spinning while inductively heating a melt spinneret attached to a pack body.

[0002]

2. Description of the Related Art Conventionally, as this type of melt spinning method, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 62-177207. In this melt spinning method, an induction coil is provided near the lower surface of a melt spinning die, and an induction current is generated in the die, thereby performing melt spinning while heating the die. According to this method, only the die can be selectively heated, so that high-speed spinning can be performed without deteriorating the polymer, and energy loss is reduced, so that there is an advantage that it is economical. is there.

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

[0004]

However, according to the above-mentioned conventional example, there are the following problems. That is,
In the melt spinning method described in Japanese Patent Application Laid-Open No. Sho 62-177207, since the induction coil is provided on the lower surface of the die, when the discharge area of the polymer is widened, the discharged filament comes into contact with the induction coil. However, there is a disadvantage that the discharge area of the first color must be set narrow.

In addition, when cleaning the base discharge surface, the induction coil hinders the cleaning, and when the pack body is attached and detached from below the spin block, the induction coil also needs to 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 Application Laid-Open No. 2-112403, since the heating method of the spinning pack is convection or radiant heating, even if the heat insulating plate is interposed, the whole pack body will be overheated for a long time. The temperature tends to be the same, and the effect of preventing polymer deterioration is reduced. In addition, there is a problem that thread separation from the base is poor.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is possible to perform high-speed spinning while preventing deterioration of a polymer, and to set a wide discharge area of a polymer. An object of the present invention is to provide a melt spinning method with good operability.

[0008]

The present invention has the following configuration to achieve the above object. That is, a first aspect of the present invention, an induction coil through between gap around the sides of the pack body spinneret for melt spinning is attached is provided, passing a low frequency current to the induction coil small <br / > and by generating induction current in the path Kkubodi also rather performs a heating quality single melting spinning the path Kkubodi.

[0009]

[0010] The invention of claim 2, claim 1
Those in a melt-spinning method described, the temperature of the portion facing the induction coil of the path Kkubodi, than the temperature of the polymer leading portion of the path Kkubodi, performs melt spinning was higher in the range of 10 ° C. or higher 0.99 ° C. below It is. Here, the temperature of the portion of the pack body facing the induction coil refers to the temperature of the outer peripheral surface of the pack body and the position of the induction coil facing the known temperature of a thermocouple, a resistance thermometer, or the like. A value measured by a measuring instrument. Further, the temperature of the polymer introduction portion of the pack body refers to a value obtained by measuring the temperature on the outer peripheral surface of the pack body and in the vicinity of the polymer introduction portion with the above-described measuring instrument.

[0011]

According to the first aspect of the present invention, 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. Since the induction coil does not interfere, the operability is improved. In addition, the pack body is heated by an induction coil provided with a gap around the side surface of the pack body to which the melt spinning die is attached, and the die portion is more effective due to heat conduction from the pack body. Heated. Therefore, the polymer melted by the melter (not shown) enters the pack body from the polymer pipe of the spin block and reaches the die, but the part of the pack body and the die facing the induction coil are heated to a temperature necessary for spinning. Therefore, the polymer is not unnecessarily heated and deteriorated before being guided from the melter to the die, and energy loss is reduced. Further, by arranging the induction coil around the lower side surface of the pack body, particularly at a position including the extended surface of the upper surface or the lower surface of the base attached to the pack body, the above-mentioned effect is enhanced. In addition, because of induction heating, the temperature rise time during heating is fast, so that the responsiveness of temperature control is good, the viscosity of the polymer can be controlled with good responsiveness, and the operability is further improved.

[0012] According to the invention described in claim 1, since the flow of low frequency current to the induction coil, the pack body and a low-frequency vibration, since the die itself vibrates, the polymer from the spinneret surface (yarn 3.) The separating effect is great, and the base itself vibrates, so that there is little dirt attached around the discharge hole. In addition, the penetration depth of the induced current generated in the pack body is deeper than when a high-frequency current is applied to the induction coil, so that the induced current is generated not only in the pack body but also in the base part, and the base part and the outer peripheral part of the base are formed. This also has the effect of reducing the temperature difference between. Generally, the penetration depth δ of the induced current is inversely proportional to the square root of the power supply frequency f. When the material to be heated is 18-8 stainless steel, δＨｚ57 mm at 60 Hz and normal temperature.

According to the second aspect of the present invention, the temperature of the 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 introduction portion of the pack body, in other words, the temperature of the spin block. By increasing the range, the polymer sent at low temperature is effectively heated,
The spinning property required for spinning can be provided. Where 1
The reason for setting the temperature to 0 ° C. or higher is that it is necessary to bring the polymer to the vicinity of the spinneret at a temperature lower than the spinning temperature by 10 ° C. or higher in order to prevent thermal deterioration of the polymer. Otherwise, the polymer will not be effectively heated. The reason why the temperature is set to 150 ° C. or lower is that it is preferable that the polymer is heated at a temperature as low as possible and immediately before the spinneret is heated to a temperature at which a necessary spinnability is obtained, particularly in the case of a polymer which is severely deteriorated. . Generally, the melting temperature of a 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 set 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 one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a peripheral portion of a melt spinning die.

In the figure, reference numeral 1 designates a pack body having a melt spinning nozzle 2 attached to the lower surface thereof, which is constituted by members 4 to 6 and 16 indicated by solid hatching in the figure. They are tightened and integrated with bolts (not shown). The pack body 1 is formed of a material in which at least the member 6 and the member 16 supporting the base 2 generate an induced current, that is, a metal such as stainless steel. It is preferable that the base 2 is also made of a material that generates an induced current.

The pack body 1 is inserted from below or above through an opening slightly larger in diameter than the pack body 1 formed in the spin block 7 and is detachably fixed by bolts 8 to prevent heat radiation on its upper surface. Heat insulating member 9 is disposed.

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

The spin block 7, as shown in FIG.
The temperature is detected by a temperature measuring sensor 17 provided as close as possible to the molten polymer introduction portion B of the pack body 1, and a known heating medium is sealed by the controller 18 so as to reach a predetermined temperature. The heating box or electric heater 19 is controlled to maintain the temperature required for sending the molten polymer into the flow path 10. Then, the temperature of the molten polymer introduction 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 disposed below the pack body 1 with a slight gap 12 (for example, about 1 to 2 mm). This induction coil 13
By interposing a magnetic shield body 15 made of, for example, a silicon steel plate between the member and the member 14 supporting the member, members other than the member facing the inner surface of the induction coil 13 are prevented from being heated as much as possible. I have. 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 based on the detection signal is supplied to the controller 18. The temperature is controlled to a preset temperature, that is, a temperature of 10 ° C. or more and 150 ° C. or less as compared with the temperature of the molten polymer introduction portion B, in other words, the temperature of the spin block 7.

The temperature measuring sensor 20 does not necessarily need to be directly mounted on the portion A, but may be mounted on the inner surface of the induction coil 13 to control the current flowing through the induction coil 13 by detecting the temperature of the gap 12. 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 this case, since the temperature of the gap 12 (atmospheric temperature) is always lower than the temperature of the portion A, the set temperature needs to be set lower. For example, when trying 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 portion A and the gap 12 varies depending on the temperature of the spin block 7 and the temperature difference between the portion A and the like, but usually does not exceed 30 ° C. Also, a plurality of induction coils can be simultaneously controlled by one temperature control device based on a signal from a temperature measurement sensor attached to one location. 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 gap allows the pack body 1 to vibrate.

As described above, since the gap 12 is interposed between the pack body 1 and the induction coil 13 disposed around the side of the pack body 1, by loosening the bolt 8 screwed to the spin block 7, The pack body 1 and the base 2 can be easily detached 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. However, in order to improve the thread separation of the polymer discharged from the base 2, the depth of the induction current is increased.
From the viewpoint of reducing the temperature difference in the radial direction, 30 to 200H
A low frequency current of z is preferred. In particular, commercial frequency (60 Hz or 50 Hz) is more preferable in terms of economy.

When an alternating current flows through the induction coil 13, an induction current flows through the pack body 1 opposed thereto, and
The lower part of the pack body 1 to which is attached is partially heated. When a low-frequency current flows through the induction coil 13, the pack body 1, that is, the base 2 vibrates at a low frequency, so that the polymer discharged from the base 2 has good thread separation.

FIG. 2 shows a pack body 1 having a diameter of 240 mm.
2 shows the temperature rise characteristics of the base 2 when induction heating is performed at a low frequency (commercial frequency) with a power of 2.13 kW.
As is clear from FIG.
It takes about 120 minutes to reach 80 ° C. At this time, the temperature rise other than the base portion was slight, and it was confirmed that 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 shape of the pack body 1 in FIG. 1 is different. In the figure,
Reference numeral P indicates an extension surface of the upper surface of the base 2, reference numeral Q indicates an extension surface of the lower surface of the base 2, and other reference numerals are the same as those in FIG. The difference from FIG. 1 is that the base support member 16 wraps the entire pack body. The pack body 1 according to the present invention may have such a modified shape. If the pack body 2 is provided with the base 2, for example, the filter is omitted or the member 4 for receiving the polymer and the base 2 are provided. A known static mixer for mixing the polymer by forming a passage that repeats the division and the merge of the polymer flow may be provided. The position of the induction coil 13 including the magnetic shield 15 in the present invention is preferably located at a position including at least one of the above-described extended surfaces P and Q (the extended surface P is included in FIG. 4). .

In order to confirm the effect of the present invention, spinning was performed under the following conditions. Melt extruding the polyethylene terephthalate chips by an extruder the screw shaft diameter is not shown 40 mm, the spin block 7 metered by a gear pump, introduced into a pack body 1 was spun from spinneret 2.
The base 2 used had a hole diameter of 0.4 mm and 120 holes. As the temperature of the pack body 1, a temperature measuring resistor 20 was provided on the outer surface of the member 6, the temperature was measured, and the current flowing through the induction coil 13 was controlled so that the temperature became 195 ° C. On the other hand, the temperature of the spin block 7 is
7 is provided on the outer surface of the member 4 and in the vicinity of the flow path 10 and its temperature is measured, and the temperature is measured so as to reach 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 Examples 1 and 2 showed the effect of suppressing the decrease in the intrinsic viscosity (IV), that is, the effect of suppressing the 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 the temperature of.

[0028]

[Table 1]

[0029]

As apparent from the above description, the present invention has the following effects. In other words, according to the first aspect of the present invention, the pack body is partially induction-heated by the induction coil provided with a gap on the side surface of the pack body to which the spinning die is attached.
Unnecessary heating of the molten polymer up to the die,
There is no deterioration and the temperature of the lower surface of the base is not lowered by the airflow on the lower surface of the base, so that a stable base temperature is always maintained. In addition, since the discharge area of the polymer is not restricted by the induction coil, and the induction coil does not interfere, the pack body can be removed from below, and cleaning of the base with the pack body attached can be performed. The operability is improved because it can be easily performed. Furthermore, since the heating time is short, the responsiveness of the temperature control is fast (the die temperature is raised from 290 ° C to 300 ° C).
When the temperature is raised to ° C., the induction heating is 60 minutes for the electric heating and the induction heating is 15 minutes for the induction heating.

According to the first aspect of the present invention, since the low frequency current is supplied to the induction coil, the base vibrates integrally with the pack body at a low frequency, so that the yarn separation from the base is improved. In addition, dirt adherence near the base discharge is reduced, the penetration depth of the induced current is deepened, the temperature difference in the base radial direction is reduced, and the operability can be further improved.

Further, according to the second aspect of the present invention, by locally increasing the temperature of the induction coil facing portion A to 10 ° C. or more and 150 ° C. or less as compared with the temperature of the molten polymer introduction portion B of the pack body, By effectively heating the polymer sent at a low temperature and imparting spinnability necessary for spinning, it is possible to stably spin a yarn without a decrease in physical properties such as a decrease in intrinsic viscosity.

[Brief description of the 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 base portion due to low-frequency induction heating.

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

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

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D01D 5 / 08,5 / 084

Claims (2)

(57) [Claims] 1. A induction coil is provided through between gap around the sides of the pack body spinneret for melt spinning is attached,
Melt spinning method characterized in that performed by also to generate an induced current path Kkubodi and reduced by passing a low-frequency current to the induction coil, the heating quality single melting spinning the path Kkubodi. 2. A melt spinning method according to claim 1, the temperature of the portion facing the induction coil of the path Kkubodi, than the temperature of the polymer leading portion of the path Kkubodi, 10
A melt spinning method in which melt spinning is performed at a high temperature in the range of not less than 150 ° C and not more than 150 ° C.