JP2000314031A - Production of high-strength polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce polyester fibers suitable for industrial materials with a good operating efficiency by sufficiently sealing all the polymer discharging holes with a gas without sticking foulings to the vicinity of the discharging holes even when carrying out the spinning of multifilaments from one spinneret. SOLUTION: The melt spinning is carried out by using a spinneret device 1 in which a spinneret plate 14 is placed on a spinneret holder 13 and the resultant filaments are then passed through the interior of a heating cylinder 3 provided directly below the spinneret device 1 and subsequently cooled to produce polyester fibers according to a spin direct drawing method. The spinneret holder 13 of the spinneret device 1 has a gas flow passage 16 for introducing a gas from the outside and communicating with the spinneret plate 14 and the spinneret plate 14 has >=100 polymer discharging holes 19 bored therein, an equalizing chamber 2 connected to the gas flow passage 16 in the undersurface near the central part thereof and further plural gas jetting holes 18 provided toward the polymer discharging holes 19. The melt spinning is conducted while blowing the gas from the gas jetting holes 18 and sealing the surface of the spinneret plate 14 with the gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spinneret plate, in which melt-spinning is performed by sealing the periphery of a polymer discharge hole with a gas, and uniformity without unevenness of fineness suitable for industrial materials such as seat belts and safety nets. The present invention relates to a method for producing a high-strength polyester fiber excellent in quality.

[0002]

2. Description of the Related Art Polyester fibers represented by polyethylene terephthalate fibers are widely used for industrial materials.
In order to improve production efficiency, multifilaments are often discharged from one spinneret, and in the field of industrial materials, multifilaments of 100 filaments or more are often spun.
And in such a case, the diameter of the spinneret used for spinning becomes large.

In the case of high-speed spinning or spinning of a high-viscosity polymer, in order to lower the orientation of the undrawn yarn and enhance the drawability, a heating cylinder is provided immediately below the spinneret to raise the ambient temperature immediately after the discharge. Adopt a way to. At this time, if the diameter of the die is large, temperature unevenness occurs between the inner and outer circumferences near the surface of the die, which causes unevenness in discharge and cooling between filaments. As a result, unevenness of fineness occurs between filaments,
There was a problem that uniform drawing was not performed and the fiber strength was insufficient. In particular, this problem is remarkable when stretching at a high magnification.

When the melt spinning is continuously performed for a long time,
A polymer or a low molecular weight substance generated from the polymer adheres around the polymer discharge hole of the spinneret. When such deposits react with oxygen in the air, they are denatured or hardened, so that the polymer is not discharged uniformly from the discharge holes, and the resulting yarn has a spot or a broken yarn. There is a problem that the property is deteriorated.

[0005] In order to prevent such a problem from occurring, the material of the die surface is made to be difficult for deposits to adhere to, a release agent is applied to the die surface to prevent adhesion, and an antioxidant is applied to the die surface. Are applied to prevent oxidation of the attached matter, and a method of sealing the periphery of the base with a gas to remove low molecular substances from the atmosphere.

[0006] Of these, Japanese Patent Publication No. 52-8115 and Japanese Patent Publication No. 58-13645 show examples of sealing the periphery of the base with gas.
Japanese Patent Application Laid-Open Publication No. H11-139,086 discloses a device for ejecting an inert gas from directly below a central portion of a base plate. In the case of this device, although the base face and the gas ejection part are provided close to each other, the uniformity of gas ejection is inferior because the equalizing chamber is not provided in the gas flow path. When the number of discharge holes is large, there is a problem that all polymer discharge holes are not sufficiently sealed with gas.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. Even when a multifilament is spun from one spinneret, all the polymer discharge holes are sufficiently filled with gas. Sealed, no dirt adheres to the vicinity of the discharge holes, and uniform discharge and cooling of the polymer is possible without causing temperature unevenness between the discharge holes, and uniform even when stretched at a high magnification. It is an object of the present invention to provide a production method capable of performing drawing and capable of obtaining high-strength polyester fibers having excellent uniformity and suitable for industrial materials.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, in the present invention, the spinneret is melt-spun using a spinneret placed on a spinneret holder, passed through a heating cylinder provided immediately below the spinneret, cooled, and once undrawn. It is a method for producing polyester fibers by a direct spinning drawing method, wherein the drawing is performed without winding, and the base holder of the base device has a gas flow path for introducing a gas from the outside and communicating with the base plate, The base plate is provided with a polymer discharge hole of 100 holes or more, a pressure equalizing chamber connected to a gas flow path is provided on a lower surface near the center, and one end is connected to the pressure equalizing chamber. Has a plurality of gas ejection holes provided toward the polymer ejection holes formed in the base plate, and blows gas from the gas ejection holes at a flow rate of 5 to 25 liters / minute, so that the entire surface of the base plate is exposed to gas. It is characterized by performing melt spinning while sealing with Method for producing a high-strength polyester fiber that is to the subject matter of.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic process diagram showing one embodiment of the manufacturing method of the present invention, FIG. 2 is a sectional explanatory view showing one embodiment of the die device of FIG. 1, and FIG. 3 is a die device of FIG. FIG. 5 is an explanatory view of the base plate of FIG. In the manufacturing method of the present invention, the spinneret plate 14 is melt-spun using the spinneret 1 placed on the spinneret holder 13, and the spun yarn passes through the heating cylinder 3 provided immediately below the spinneret 1. Thereafter, the polyester fiber is cooled by the cooling device 4 and the polyester fiber is produced by a direct spinning method of drawing without unwinding the undrawn yarn once.

After the oil agent is applied to the cooled and solidified yarn 12 by the oiling roller 5, the drawing is performed. The drawing may be performed in one step or in multiple steps. In the case of FIG. 1, the first-stage stretching is performed between the take-up roller 6 and the first roller 7, and the second-stage stretching is performed between the first roller 7 and the second roller 8. In the case of thermal stretching, the first roller 7 and the second roller 8 may be used as heating rollers, or a heat treatment apparatus 10 such as a heater may be provided between the rollers to perform heat treatment. Then, after the stretching, after passing through the third roller 9 as necessary, the winding machine 11 may be used for 2500 to 500
Wind at a speed of 0 m / min.

The heating cylinder 3 is provided to raise the ambient temperature of the yarn immediately after spinning, thereby lowering the orientation of the undrawn yarn and increasing the drawability.
The inner wall temperature is 250-450 ° C and the length is 50-4
It is preferably provided with a diameter of 00 mm, which is provided immediately below the die device 1.

The spinning device 1 for melt spinning used in the present invention is a die device in which a die plate 14 is mounted on a die holder 13, and a gas flow for introducing a gas from the outside into the die holder 13. A road 16 is provided. Base plate 1
4, a pressure equalizing chamber 2 is provided on the lower surface at a position closer to the center than the polymer discharge hole 19 drilled at the most center side on the die surface. And is connected to the gas flow path 16. Further, one end of the pressure equalizing chamber 2 is connected to the pressure equalizing chamber 2 and the other end is connected to the base plate 1.
A plurality of gas ejection holes 18 are provided upward toward the polymer ejection holes 19 perforated in FIG.

One end of the gas passage 16 has a base 13
Is connected to a gas introduction unit 15 (the lower surface of the base holder 13 in FIG. 1), which is a gas supply source provided at an arbitrary position, and the other end communicates with the pressure equalizing chamber 2 in the base plate 14. I have.
In order to improve the uniformity of the air flow, a plurality of gas flow paths 16 and a plurality of gas supply sources may be provided.

The pressure equalizing chamber 2 makes the pressure of the gas substantially uniform by once filling the space with the gas.
It is provided at a position closer to the center than the polymer discharge hole 19 of the base plate 14, and may be a shape including the center point of the base plate 14 or a shape not including the center point (FIG. It is a circular shape including the center point of the base plate 14).

The pressure equalizing chamber 2 may be formed integrally with the die plate 14 with the die surface as the upper surface, or may be formed with the die surface as the upper surface, and the other closed cylindrical part may be in close contact with a gasket to make the pressure equalizing chamber 2. Is preferably formed, and the inner volume is preferably about 5 to 100 cc in order to enhance the uniformity of gas ejection.

Further, the pressure equalizing chamber 2 has a gas ejection hole 18 having one end connected to the pressure equalizing chamber 2 and the other end opened toward the polymer discharge hole 19 of the base plate 14. A plurality is provided along. The number of gas ejection holes depends on the number of polymer ejection holes formed in the die plate, but is preferably about 5 to 100, and it is preferable to provide them at substantially uniform intervals.

When the gas is supplied from the gas introducing section 15, it is led into the pressure equalizing chamber 2 through the gas flow path 16, and is introduced into a plurality of gas ejection holes 18 connected to the pressure equalizing chamber 2, and the polymer It is ejected toward the discharge hole 19.

The gas ejection hole 18 has an upward angle θ of 1.5 to 25 ° from the horizontal toward the upper polymer ejection hole 19.
It is preferable to provide them so that This angle θ is 1.
If it is less than 5 °, the gas will be ejected in a direction substantially horizontal to the surface of the die, and the ejected gas will flow downward due to the accompanying flow generated by the yarn flow, making it difficult for the ejected gas to touch the surface of the die, The periphery of the polymer discharge hole 19 cannot be sufficiently sealed. On the other hand, when the angle θ exceeds 25 °, the ejected gas touches the base surface, but the gas is intensively ejected around the inner periphery of the base plate 14, and the vicinity of the base plate outer peripheral portion distant from the ejection hole. The polymer discharge hole 19 cannot be sufficiently sealed.

The shape of the gas ejection hole 18 is not particularly limited.
Circular and slit shapes are mentioned. The size is not particularly limited. For example, when the shape is circular, the diameter is preferably about 0.1 to 5 mm. If it is less than 0.1 mm, the gas flow tends to be insufficient, and if it exceeds 5 mm, it is difficult to uniformly eject the gas.

In the method of the present invention, a gas is blown from the gas outlet at a flow rate of 5 to 25 liters / minute, and melt spinning is performed while sealing the entire die plate surface with the gas. This flow rate refers to the total amount of gas blown from a plurality of gas ejection holes. The gas is blown out to control the temperature of the atmosphere just below the surface of the die plate, to make the yarn uniform, and to seal the entire die plate surface to prevent polymer adhesion and prevent yarn breakage. It is.

When the flow rate is less than 5 liters / minute, this effect becomes insufficient, and when the flow rate exceeds 25 liters / minute, the jetted air current affects the formation of the yarn, causing yarn spots.
The uniformity of the yarn may be deteriorated. If the flow rate is 25 liters / minute or less, the liquid is heated to the same temperature as the temperature of the die while passing through the gas flow path. It is efficient without the need for heating.

As the polyester to which the method of the present invention can be applied, polyethylene terephthalate (PE)
T), polybutylene terephthalate and polypropylene terephthalate as main components, of which PET is preferable. These polyesters may contain a small amount of a copolymer component as long as the effect is not impaired.In addition, heat-resistant agents, light stabilizers, fluorescent agents, antioxidants, matting agents, antistatic agents , A pigment, a colorant, a flame retardant, a reinforcing agent, a lubricant, an antistatic agent, and the like.

In the present invention, the gas to be jetted is not particularly limited as long as it can prevent a polymer or a low molecular weight substance generated from the polymer from adhering around the polymer discharge hole. Normally, it is preferable to use air in consideration of safety and cost. In addition, when it is necessary to express the effect to a higher degree, if the polymer to be spun or a gas having low reactivity with the deposit on the die surface is used, an effect of preventing the deterioration of the deposit on the die surface or the like is provided. In such a case, it is preferable to use steam, nitrogen, or the like.

The structure of the portion other than the gas flow path, the pressure equalizing chamber, and the gas ejection holes of the base device may be the same as that of a normal base device, and the material of the base device is not particularly limited. Stainless steel or the like is used similarly to the apparatus.

The method of the present invention is particularly effective when the base plate is provided with 100 or more polymer discharge holes and the diameter of the base plate is 105 mm or more. The polyester fiber obtained in the present invention has a fiber diameter variation rate of 2.5% or less at the stage of an undrawn yarn as an index indicating uniformity during spinning, and can be drawn at a high drawing ratio. As a result, a high-strength polyester fiber having a strength of 10.0 g / d or more and an elongation of 10 to 20% is obtained.

[0026]

Next, the present invention will be described specifically with reference to examples. The measurement of the characteristic values in the present invention was performed as follows. (A) Strong elongation Measured using a Shimadzu Autograph S-100 under the conditions of a sample length of 25 cm and a tensile speed of 30 cm / min. (B) Fluctuation in fiber diameter The spun yarn was wound around a take-up roller, undrawn yarn was sampled, and all fiber diameters were measured with a microscope, and the standard deviation was divided by the average value. (C) Filament spots (U%) The fineness spots were measured by a normal test using a Worcester tester / spot count measuring device manufactured by Zelbegger, Switzerland.

Examples 1-2, Comparative Examples 1-3 PET chips having an intrinsic viscosity of 1.05 were supplied to an extruder type melt spinning apparatus, and were wound from melt spinning according to FIG. 1 using a die apparatus shown in FIGS. I went up. First,
The base holder of the base device has one gas flow path, and the base plate has 180 discharge holes with a circular cross section of 0.6 mm in diameter, which are arranged in a quadruple with a diameter of 230 mm.
A pressure equalizing chamber (80cc) is provided at the lower center of the base of the base, and 36 gas ejection holes have an upward angle θ of 3.4 °.
What was provided almost uniformly around the equalizing chamber so that it might become. Then, while the flow rate of the gas (nitrogen) blown from the gas ejection holes was changed variously so as to be as shown in Table 1, the atmosphere temperature near the base surface was controlled to be the temperature shown in Table 1 while blowing. A yarn spun from such a spinneret at a spinning temperature of 300 ° C. is passed through a heating cylinder having an inner wall temperature of 300 ° C. and a length of 300 mm, and then a cooling air having a temperature of 15 ° C. is blown at a speed of 1.0 m / sec. Cooling was performed by spraying from the circumferential direction over a length of 300 mm at a speed. Then, after applying the spinning oil with an oiling roller, it was taken up by a non-heated take-up roller, and the obtained undrawn yarn fiber yarn was continuously drawn without being once taken up, and then taken up to give a drawn yarn. At this time, the stretching is performed in two stages, the first stage of stretching is performed between the unheated take-off roller and the unheated first roller, and then the first roller and the second roller heated to a surface temperature of 260 ° C. (Nelson type), the second stage of stretching is performed while performing steam heat treatment using a heat treatment device that sprays steam at a temperature of 450 ° C. disposed 15 cm downstream from the first roller. Rolled up. Table 1 shows the take-up roller speed and total draw ratio.
Various changes were made as shown in FIG.

Example 3 A PET chip having an intrinsic viscosity of 1.19 was supplied to an extruder type melt spinning apparatus, and the steps from melt spinning to winding were carried out according to FIG. 1 using a die apparatus shown in FIGS. First,
The cap holder of the cap device is provided with one gas flow path. The cap plate has 252 discharge holes with a circular cross section of 0.6 mm in diameter, and these are arranged in a quadruple with a diameter of 230 mm.
A pressure equalizing chamber (80cc) is provided at the lower center of the base of the base, and 36 gas ejection holes have an upward angle θ of 3.4 °.
What was provided almost uniformly around the equalizing chamber so that it might become. Then, gas (nitrogen) is blown from the gas outlet at a flow rate of 10 l / min.
The temperature was controlled to 6 ° C. A yarn spun from such a spinneret at a spinning temperature of 300 ° C. is passed through a heating cylinder having an inner wall temperature of 300 ° C. and a length of 130 mm, and then a cooling air having a temperature of 15 ° C. is blown at a speed of 1.0 m / sec. Cooling was performed by spraying from the circumferential direction over a length of 300 mm at a speed. Then, after applying the spinning oil with an oiling roller, the unheated take-off roller takes 1667 m /
The obtained undrawn yarn fiber yarn was continuously drawn without being wound up at a draw ratio of 2.70 and then wound up to obtain a drawn yarn. At this time, the stretching is performed in two stages, the first stage stretching is performed at a stretching ratio of 1.5 between the unheated take-off roller and the unheated first roller, and then the first roller is heated to a surface temperature of 260 ° C. 2nd roller (Nelson type)
Between the first roller and the temperature located 15 cm downstream from the first roller
While performing a steam heat treatment using a heat treatment apparatus that injects steam at 450 ° C., the second stretching was performed so that the total stretching ratio became 2.70, and the film was wound by a winder.

Comparative Example 4 The procedure of Example 3 was repeated, except that the gas was not ejected from the gas ejection holes, and the speed of the take-off roller and the total stretching ratio were changed as shown in Table 1.

The physical properties of the fibers obtained in Examples 1 to 3 and Comparative Examples 1 to 4 in the state of undrawn yarn, various physical property values after drawing, and the cycle of the surface cleaning of the base (base cleaning cycle) Are shown in Table 1.

[0031]

[Table 1]

As is clear from Table 1, in Examples 1 to 3, no fineness unevenness occurred in an undrawn yarn state, and the fiber obtained by drawing had small yarn unevenness and uniform yarn. Excellent,
Excellent in strength and elongation. In addition, it can be seen that the surface sweep cycle was long, and it was difficult for dirt to adhere. On the other hand, Comparative Example 1,
In Nos. 2 and 4, since the flow rate of the gas blown from the gas ejection holes was too small, the fineness unevenness in the state of the undrawn yarn caused by the cooling unevenness became large, and the drawn yarn was inferior in strength and U%
Was also big. Further, dirt around the discharge hole could not be prevented, the cycle of the surface sweep was short, and workability was poor. In Comparative Example 3, since the flow rate of the gas blown from the gas ejection holes was too large, the yarn swayed, the air flow had an adverse effect on the formation of the yarn, the yarn was uneven, and the uniformity of the yarn was poor.

[0033]

According to the present invention, even when a multifilament is spun from one spinneret, all polymer discharge holes are sufficiently sealed with gas, and no dirt adheres near the discharge holes. Also, without causing temperature unevenness between the discharge holes, it is possible to uniformly discharge and cool the polymer, and to perform uniform stretching even when performing stretching at a high magnification.
A high-strength polyester fiber having excellent uniformity can be obtained with good operability, and can be suitably used for industrial materials such as seat belts and safety nets.

[Brief description of the drawings]

FIG. 1 is a schematic process diagram showing one embodiment of a method for producing a high-strength polyester fiber of the present invention.

FIG. 2 is an explanatory sectional view showing an embodiment of the spinneret device of FIG. 1;

FIG. 3 is an explanatory view of a base plate of the base device of FIG. 2 as viewed from below.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap device 2 Equilibrium chamber 3 Heating cylinder 10 Heat treatment device 11 Winder 12 Thread 13 Cap base 14 Cap plate 15 Gas introduction part 16 Gas flow path 18 Gas ejection hole 19 Polymer discharge hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4L035 AA08 BB32 BB36 BB52 BB56 BB80 BB89 BB91 EE08 FF01 4L045 AA05 BA03 BA49 BA60 CB13 CB16 CB33 DA08 DA15 DA17

Claims (1)

[Claims] 1. A die plate is melt-spun using a die device placed on a die holder, passed through a heating cylinder provided immediately below the die device, cooled, and once wound with an undrawn yarn. A method for producing a polyester fiber by a direct spinning drawing method, wherein the drawing is performed without taking, and the base holder of the base device has a gas flow path for introducing gas from the outside and communicating with the base plate. The plate is provided with 100 or more polymer discharge holes, a pressure equalizing chamber connected to the gas flow path is provided on the lower surface near the center, and one end is connected to the equalizing chamber and the other end is connected to the equalizing chamber. It has a plurality of gas ejection holes provided toward the polymer ejection holes formed in the base plate, and blows gas at a flow rate of 5 to 25 liters / minute from the gas ejection holes, so that the entire surface of the base plate is exposed to gas. High spin characterized by performing melt spinning while sealing Manufacturing method of high-strength polyester fiber.