JPH07157914A - Production of polyester fiber and heating apparatus for high-speed fiber making - Google Patents

Abstract

PURPOSE:To uniformize the environmental temperature profile in a heat- treatment cylinder, improve the maintainability of apparatus and improve the threading performance by placing a specific apparatus for suppressing the inflow and outflow of air at an upper part or a lower part of a heat-treatment cylinder for a hot-tube draw-spinning process. CONSTITUTION:The slit 9 of an apparatus for suppressing the inflow and outflow of air is formed of front and rear guides 11, 11' and left and right guides 12, 12' dividable by horizontally sliding or rotating through guide-attaching members 10, 10'. The apparatus for suppressing the inflow and outflow of air is opened in the case of threading and closed in winding to suppress the flow of air between the inside and the outside of a heat-insulation zone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester fiber, and more particularly to a method for producing a polyester fiber satisfying the characteristics that can be put to practical use only in a spinning step, and more specifically, a polyester fiber having a large residual elongation. The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, a high-speed spinning method capable of obtaining fibers sufficiently satisfying practical properties without passing through a drawing step by setting a take-up speed to 4000 m / min or more is aimed at improving productivity. It has been developed and put to practical use.

This high-speed spinning method includes an ultra-high-speed spinning method in which a yarn melt-discharged from a spinneret is drawn as it is at 5000 m / min or more, and once it is cooled and solidified, it is stretched while being reheated in a heating atmosphere such as a hot tube. Heat treated 400
There are a hot tube stretch spinning method of drawing at 0 m / min or more, a direct spinning drawing method of drawing with a first take-up roll, drawing with a second take-up roll, and drawing at 4000 m / min or more.

Of these, the yarn obtained by the ultra-high-speed spinning method has features such as good dyeability and softness due to a small Young's modulus, but its physical properties and fiber structure are fundamentally different from those of the conventional drawn yarn, and therefore, conventional Cannot be used as a substitute for the drawn yarn of

On the other hand, the yarn obtained by the hot tube draw-spinning method has a physical property similar to that of a so-called drawn yarn, which is a yarn produced by the conventional two-step spin-drawing method, and therefore, it is suitable for use as a conventional drawn yarn. Deployment is possible.

In the hot tube draw-spinning method, the running yarn is generally passed through a heat-treating cylinder such as a hot tube to perform non-contact heat treatment. For this reason, the threading is complicated and the heat-treating cylinder is not heated. The inflow of the accompanying air flow was a problem.
When the cold airflow accompanying the yarn flows into the heat treatment cylinder, the heating fluid flows out from the lower portion of the heat treatment cylinder, and the thermal efficiency decreases. These two factors increase the inflow volume of the associated airflow when the opening is widened to eliminate complications, and it is troublesome to take measures to separate the associated airflow and prevent leakage of the outflow airflow in order to suppress the inflow rate. Is a contradictory issue of increasing

Further, in Japanese Patent Application No. 4-147668, cold air flows into the heat treatment cylinder, so that the atmospheric temperature at the upper part of the heat treatment cylinder lowers, and the temperature in the heat treatment cylinder is adjusted to perform a sufficient heat treatment. When the temperature is raised, the ambient temperature of the lower part of the heat-treated cylinder excessively rises, and the yarn after stretching is excessively drawn, which causes a decrease in the elongation of the produced fiber,
It has been found that this tendency is particularly remarkable in the case of ultrafine fibers having a single yarn denier of 1.5 denier or less.

In order to solve these contradictory problems at the same time, in JP-A-61-252311, openable and closable lids are attached to the front and rear of the processing cylinder to prevent the air flow in and out of the heat treatment cylinder and to thread the thread. However, since it is necessary to pass the thread through the slit attached to the lid again after dropping the thread, the auxiliary lid must be closed and the slit width regulation guide must be adjusted. It was

Further, in Japanese Unexamined Patent Publication (Kokai) No. 5-98505, an aspirator with a movable throttle mechanism that can change the diameter of the yarn delivery port is provided in the lower part of the heating cylinder, and the purpose is to improve the threading property and heat exchange efficiency. However, since the movable throttle mechanism needs a slight gap between each throttle valve, it is structurally difficult to prevent leakage of the airflow from the throttle valve, and since it is composed of a plurality of throttle valves, The structure is complicated,
In order to prevent malfunctions due to the attachment of thread waste or the like to the gaps between the throttle valves, the amount of maintenance work of the device increases.

[0010]

SUMMARY OF THE INVENTION In the present invention, the number of constituent parts is greatly reduced, the maintainability of the device is improved, and at the same time, the threading property is improved. It is possible to suppress the inflow and outflow of the air flow to keep the atmosphere temperature profile in the heat treatment cylinder constant, suppress an excessive rise in the atmosphere temperature in the lower portion of the heat treatment cylinder, and especially to eliminate the decrease in elongation of the fiber typified by ultrafine fibers. To aim.

[0011]

The object of the present invention described above is that in the melt spinning in which polyester is discharged from a spinneret, cooled and solidified, and then reheated in a heating zone up to a take-up device. Alternatively, the present invention is achieved by a method for producing a polyester fiber characterized by using an airflow inflow / outflow suppression device that can divide the device itself in the lower part, and as a heating device for high-speed spinning, an airflow inflow / outflow device that can divide the device itself in the upper part or the lower part. This can be achieved by installing a suppressor.

The present invention will be described in detail below. First, the method for producing a polyester fiber of the present invention will be specifically described with reference to FIG. Polyester at about 290 ℃ 1
Discharge from. After passing the discharged yarn Y through the heat-retaining zone 2 below the mouthpiece 1, the chimney 3 blows air perpendicularly to the yarn to cool the yarn Y below the glass transition temperature once and set it under the mouthpiece 1. The polyester fiber of the present invention is introduced into the hot tube 4 and subjected to stretching heat treatment, then oiled by the oil supply device 5, subsequently entangled by the entanglement device 6, taken up by the pair of gody rolls 7 and wound by the winder 8 to obtain the polyester fiber of the present invention. can get. At the lower part of the hot tube 4, an airflow inflow / outflow restraint device having an openable / closable slit portion as shown in FIG. 3 is attached.

In the polyester of the present invention, the main dicarboxylic acid component constituting the polyester is preferably a terephthalic acid component, but other dicarboxylic acid components may be used within the range not departing from the object of the present invention. The main diol component constituting the polyester of the present invention is preferably ethylene glycol, but other components, for example,
1,4-butanediol, 1,6-hexanediol,
A diol component such as polyethylene glycol, polytetramethylene glycol, or 1,4-cyclohexanedimethanol may be used without departing from the object of the present invention. Further, various additives such as a matting agent, a flame retardant, an antioxidant, an ultraviolet absorber, an infrared absorber, a crystal nucleating agent, and a brightening agent may be added to the polyester of the present invention as required. It may be copolymerized or mixed.

In melt spinning, the polyester melted and discharged from the spinneret is once cooled by cooling air. The cooling is performed until the temperature at which the polyester yarn solidifies, that is, the glass transition temperature or less, so that the subsequent drawing heat treatment can be stably performed. If the yarn is introduced into the heating zone before sufficient cooling takes place, the drawing becomes unstable and the homogeneity of the obtained yarn is impaired.

The distance from the spinneret surface to the inlet of the heating zone is a proper condition of a normal single yarn denier of 1.5 to 3.0 denier, and sufficient yarn cooling under the spinneret surface, workability, and air resistance. Considering the tension generated by the force, 1.0 to 2.5
m is preferred.

In melt spinning, the polyester melted and discharged from the spinneret is once cooled by cooling air. The cooling is performed until the temperature at which the polyester yarn solidifies, that is, the glass transition temperature or less, so that the subsequent drawing heat treatment can be stably performed. If the yarn is introduced into the heating zone before sufficient cooling takes place, the drawing becomes unstable and the homogeneity of the obtained yarn is impaired.

The ambient temperature Tc in the heating region needs to be higher than the glass transition temperature of the polyester in order to maintain practical strength and thermal stability of the fiber and to prevent uneven treatment, but sufficient heat treatment is required. Therefore, 110 ° C or higher is preferable, and 130 ° C or higher is more preferable. Further, Tc is preferably equal to or lower than the melting point, and more preferably 200 ° C. or lower from the viewpoint of energy cost, in order to obtain uniformity between the single yarns in the longitudinal direction of the fiber and a uniform yarn.

FIG. 2 shows the temperature distribution in the heating zone. All the curves in FIG. 2 show the same heat-setting property, that is, the temperature gradient required for the same boiling water shrinkage, when the spinning method of the present invention is applied under the condition of 5000 m / min. . No. 2 in FIG. 1 is the temperature distribution in the steady state when the method of the present invention is adopted.
o. 2 is a temperature distribution when a method other than the present invention is adopted. No. When the temperature distribution is 1, the ultrafine product having a single yarn of 1.5 denier or less can be wound with high elongation without lowering the spinning speed, which is the object of the present invention. The reason is that No. 2 in FIG. When the temperature in the latter half is high as in No. 2, it is presumed that the yarn is exposed to high stress due to air resistance and a high temperature atmosphere, and excessive stretching occurs, resulting in low elongation. No. In the temperature distribution of No. 1, the temperature of the latter half is moderately low, and therefore it is considered that such excessive stretching does not occur and the elongation reduction can be suppressed.

No. of heating zone The temperature gradient of 1 is achieved, for example, by a method of providing an airflow inflow / outflow suppression device at the inlet or outlet of the heating zone. The method of achieving the temperature gradient is not limited in any way, but it is preferable to provide an airflow inflow / outflow suppression device in view of facility simplicity and operating costs.

In order to freely stretch the yarn in the heating region, it is preferable that nothing is brought into contact with the yarn other than the airflow inflow / outflow restraint device at the inlet or the outlet.

Here, the inlet of the heating zone refers to the cross-sectional area of the narrowest portion where the yarn is introduced into the heating zone, and the outlet refers to the narrowest portion where the yarn exits the heating device.

The airflow inflow / outflow suppression device means a device having a function of positively separating the airflow associated with the yarn from the yarn,
The shape of the opening is (cross-sectional area) / (perimeter) [mm ² /
The value of [mm] is preferably 1.0 or less. As a result, it is possible to prevent the accompanying airflow of the yarn from entering the heating cylinder and the outflow of the heating airflow in the heating cylinder. When the heated gas or the like in the heating cylinder is not blown in, the carry-in amount of the accompanying flow becomes equal to the outflow amount of the heated gas, so the airflow inflow / outflow suppression device may be used at either the upper part or the lower part of the heating cylinder. The cross-sectional shape of the yarn running portion of the airflow inflow / outflow suppression device can be any shape such as circular, slit-shaped, polygonal, cruciform, or curved, but when the airflow inflow / outflow suppression device bundles the yarns, The heat exchange property of the central portion of the yarn is deteriorated, drawing unevenness is caused, or heat setting property is insufficient, resulting in a difference in physical properties between the single yarns. In order to perform sufficient heat treatment while effectively separating the entrained airflow, it is preferable that the cross-sectional shape be slit-like so that the yarns can be aligned and heat-treated, and the width of the slit is preferably 2 mm or less, more preferably 1 mm. The following is more preferable.

FIG. 3 shows an example of a slit-like airflow inflow / outflow restraint device. The slit width of the above-mentioned slit 9 is D in FIG.
Indicated by. Slits are guide mounting members 10, 10
It is formed by the front and rear guides 11 and 11 ′ attached to the ‘ Further, the slit length L does not need to be unnecessarily lengthened, and is set to a range smaller than the inner diameter of the heat retaining zone by the left and right guides 12 and 12 '. The device itself has a structure in which the device itself is separable, and one or both of the guide attachment members 10, 10 'is slidably or rotationally movable to open during threading and close during winding. In the closed state, the sealing surface 13 can prevent the airflow in and out of the heat retention zone. With this slit,
Moreover, by making the slit part itself separable so that it can be opened and closed, it is possible to solve both problems of inflow and outflow of the accompanying air current into and out of the heat treatment cylinder and the complexity of threading at the same time. Since it is simple, it is possible to prevent malfunctions due to leakage of airflow and adhesion of foreign matter, and increase in the amount of maintenance work of the device. FIG. 4 shows a slide-type slit-like airflow inflow / outflow suppression device, which is in an open state. The slide type structurally has a good sealing property and also has a good device durability.
FIG. 5 shows a slit-shaped airflow inflow / outflow restraint device in which the guide attachment member is a rotary type, and shows an open state. FIG. 5a shows the guide mounting member 10 which can be opened and closed in the front-rear direction, and has good operability. Further, the guide mounting member 10 may be one that can be opened and closed in the left-right direction as shown in FIG. 5b. The guide attachment members 10 and 10 'may be opened and closed as shown in FIG. 4 or may be opened and closed on only one side as shown in FIG. In the latter case, it is preferable that the back side of the guide attachment member 10 'be provided with an inclined portion facing the front and rear guides 11' so that the thread can be easily threaded through the hot tube.

Further, when the cross-sectional shape is slit-like, it is preferable to run the yarns so that the yarns are not unevenly distributed at the slit ends in order to prevent a difference in physical properties between the single yarns. For that purpose, a method such as optimizing the positions of the yarn collecting guide and the oil agent applying guide thereunder is adopted.

The airflow inflow / outflow suppressing device may be provided at either the inlet or the outlet of the heating zone, or may be provided at only one of the heating regions. However, since the undrawn yarn is easily scratched by rubbing with the separating device, In order to prevent breakage, generation of fluff on the drawn yarn, and reduction in strength, it is preferable to provide the airflow inflow / outflow suppression device at the outlet portion that comes into contact with the drawn yarn.

As the heating area, a tube or a tube having a rectangular cross section can be used, but any shape can be used as long as it can heat the space in which the yarn runs. As a heating method of the heating area, there is a method of heating with a heating medium or a heating wire from the surroundings, dry heated air introduced by heating, a method of filling saturated steam or heating steam, but in order to uniformly heat the heating area, A heating medium heating method, a method of introducing a heating medium into the heating zone, and a method of combining these are preferable. The length of the heating zone is preferably 0.5 to 3.0 m from the viewpoint of stable stretching heat treatment and energy saving.

The take-up speed is determined in consideration of the fineness, mechanical properties, spun yarn breakage, improvement in productivity, etc. of the obtained fiber. In order to obtain a conventional drawn yarn only by the spinning process, 45
00 m / min or more is preferable.

[0028]

EXAMPLES Each characteristic value in the examples was determined according to the following method.

(A) Atmosphere temperature measurement A CA thermocouple was used for actual measurement during spinning.

(B) Fiber Strength and Elongation Determined from a load elongation curve using a Tensilon tensile tester manufactured by Orientec. Examples 1 to 3 and Comparative Examples 1 and 2 Polyesters having an intrinsic viscosity [η] = 0.64 were melted at 290 ° C., and the spinning device shown in FIG. After passing the discharged yarn through the heat-retaining zone (about 20 cm) under the spinneret, blow air at 25 m / min, about 25 ° C, perpendicularly to the yarn for 1 m to cool the yarn once to room temperature. Introduced into the yarn into a hot tube with a length of 1.5 m and an inner diameter of 30 mmφ installed 2 m below the spinneret, and after drawing heat treatment, lubrication and entanglement are applied to 5000 m /
A polyester fiber of 50 denier / 48 filaments was obtained by winding with a take-up winder using a pair of gody rolls per minute.

Table 1 shows the inlet shape, the outlet shape, the atmospheric temperature in the hot tube, and the yarn characteristics of the obtained fiber of the airflow outflow / inflow suppressor attached to the yarn lead-out inlet of the hot tube. As is clear from this table, the use of the airflow inflow / outflow suppression device of the present invention makes it possible to obtain a yarn which has a very short residual thread elongation in practical use and which has a practically sufficient residual elongation. Here, the practically sufficient residual elongation is 30% or more, and more preferably 33% or more.

In Comparative Examples 1 and 2, the shape of the opening of the airflow inflow / outflow suppressing device used was (cross-sectional area) / (perimeter) [m
m ² / mm] exceeds 1.0, the residual elongation is 3
It will be less than 0%.

[0033]

[Table 1] Examples 4 to 5 and Comparative Example 3 The thickness of the taken-up yarn is 50 denier / 72 filaments,
The same method as in Example 1 was carried out except that the die was changed to 50 denier / 24 filament. Table 2 shows the inlet shape, the outlet shape, the atmospheric temperature in the hot tube, and the yarn characteristics of the obtained fibers, of the airflow inflow / outflow suppression device attached to the yarn outlet of the hot tube.

When the method of the present invention is adopted, the residual elongation does not change greatly and the conventional yarn quality is produced whether the single yarn fineness is 1 denier or less or the single yarn fineness is 2 denier. It is possible.

[0035]

[Table 2]

[0036]

The following effects can be obtained by adopting the present invention. (1) In the hot-tube stretch-spinning method, the complexity of threading and the inflow / outflow of the airflow into and out of the heat treatment cylinder can be suppressed, and efficient heat treatment can be performed. Further, the maintenance work amount of this airflow inflow / outflow restraint device can be reduced. (2) It is possible to manufacture ultrafine fibers with little variation in boiling yield. (3) Since a single yarn having a residual elongation of practically 1.5 denier or less can be obtained, the success rate of switching when using the automatic switching winder can be significantly improved, and the high-order processability is also improved. .

[Brief description of drawings]

FIG. 1 is a schematic view of a method for producing a polyester fiber according to the present invention.

FIG. 2 shows a temperature gradient in a heating zone of the present invention (No. 1) and a temperature gradient in a conventional heating zone (No. 2).

FIG. 3 is a schematic view of an airflow inflow / outflow suppression device that is preferably used in the manufacturing method of the present invention.

FIG. 4 is a schematic view of a slide type slit-like airflow inflow / outflow suppression device in an open state.

FIG. 5 is a schematic view of a slit-shaped airflow inflow / outflow suppression device in which a guide attachment member in an open state is a rotary type.

[Explanation of symbols]

 1 Mouth 2 Heat insulation zone 3 Chimney 4 Hot tube 5 Oil supply device 6 Entangling device 7 Gody roll 8 Winder 9 Slit 10, 10 'Guide mounting member 11, 11' Front-rear guide 12, 12 'Left-right guide 13 Sealing surface

Claims (4)

[Claims] 1. A melt-spinning process in which polyester is discharged from a spinneret, cooled and solidified, and then reheated in a heating zone up to a take-up device, in which the device itself can divide into an upper portion or a lower portion of the heating region. A method for producing a polyester fiber, which comprises using an entrance control device. 2. The method for producing a polyester fiber according to claim 1, wherein the yarn passage opening of the airflow inflow / outflow suppressing device has a slit shape. 3. An airflow inflow / outflow suppression device, which can be divided by the device itself, is installed in the upper or lower part of a heating area in which the material is discharged from a spinneret by melt spinning, cooled and solidified, and then reheated up to a take-up device. Characteristic heating device for high-speed spinning. 4. The heating device for high-speed yarn production according to claim 3, wherein the yarn passage opening of the airflow inflow / outflow restraint device has a slit shape.