JP2000345428A - Production of polyolefin-based fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyolefin-based fiber highly oriented by a stretching method directly joined with a spinning simply at a low cost. SOLUTION: This method for producing a polyolefin-based fiber is to spin a polyolefin having >=0.01 melt index(MI) from a spinneret 3 by melting it, pass the spun yarn through a heated towing zone 4 of which temperature is kept lower than the melting temperature (Tm) of the polyolefin directly below the spinneret and also within a temperature range (ΔT) in which the spun polymer does not essentially crystallize, introduce the spun yarn into heated zones 7, 8, 9 while keeping >=Tm-|ΔT| temperature of it, stretch the spun yarn by >=8 fold in the heated zones and wind the stretched yarn with a winding means 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a spinning direct drawing method (d
More particularly, the present invention relates to a low-cost and simple method for producing a polyolefin-based fiber which can be highly drawn by a single-stage drawing operation.

[0002]

2. Description of the Related Art Conventionally, polyolefin fibers such as polyethylene and polypropylene have been used for various purposes such as clothing, living materials, fishing nets and ropes.
The production of polyolefin fibers is often performed by a melt spinning method. That is, for example, "Textile Handbook"
(Edited by Textile Machinery Society, published March 25, 1994, Maruzen)
As described on page 29, the molten polymer is extruded from a die using an extruder and a gear pump to form a yarn,
The yarn is passed through the spinning tube, cooled and solidified by cooling air, oil is applied by an oiling roller, passed through a godet roller, and wound by a winder, thereby producing a thermoplastic synthetic fiber. The undrawn yarn obtained here is drawn in another heating and drawing step to obtain a drawn yarn having practical strength. Instead of cooling with cooling air, undrawn yarn after spinning is put into a cooling water tank and quenched.

However, in the conventional melt spinning method, after the undrawn yarn is cooled and solidified, it is heated and drawn in another step, and a sufficiently high draw ratio cannot be obtained. Moreover, since spinning and drawing are performed in separate steps, productivity is low.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a method for easily producing a polyolefin fiber which has been highly drawn by a direct spinning drawing method at low cost. Is to do. Another object of the present invention is to provide a polyolefin fiber having a practically sufficient performance obtained by this production method.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that it is possible to perform high stretching by spinning a molten polymer and then performing heating stretching without cooling. Completed the invention.

That is, according to the present invention, a polyolefin is melted and spun from a spinneret, and a temperature range (ΔT) below the melting temperature (Tm) of the polyolefin immediately below the spinneret and where the spun polymer does not substantially crystallize. ), The spun yarn is guided to the heating zone downstream of the heating spinning zone while maintaining the temperature of Tm- | ΔT | or higher, and the spun yarn is heated in the heating zone. A method for producing a polyolefin-based fiber, comprising drawing and winding a drawn yarn using a winding means. In the present invention, the melt index (MI) of the polyolefin is usually
It is 0.01 or more.

In the present invention, the polyolefin is not particularly limited, but for example, polyethylene, polypropylene, polybutene-1, MI: 0.01 or more,
It is selected from the group consisting of a copolymer of polyethylene and polypropylene, and a binary or ternary blend polymer containing polyethylene and / or polypropylene as a main component. In the present invention, the stretching ratio in the heating zone is, for example, 1.5 times or more, preferably 8 times or more, more preferably 10 times or more, or 12 times or more.

[0008] To produce polyethylene fibers, a polyethylene having a melt index (MI) of 0.01 or more is used, and the temperature of the heated spinning zone is maintained at a temperature lower than the melting temperature of the polyethylene and 40 ° C or more, and heating is performed. The spun yarn may be heated and drawn at a draw ratio of 1.5 times or more in the heating zone while maintaining the temperature of the zone in the range of 40 ° C to 160 ° C.

In order to produce a polypropylene fiber, a polypropylene having a melt index (MI) of 0.01 or more is used, and the temperature of the heated spinning zone is maintained at a temperature lower than the melting temperature of the polypropylene and 30 ° C. or more. ,
The temperature of the heating zone is preferably kept in the range of 30 ° C. or more and 190 ° C. or less, and the spun yarn may be heated and drawn at a draw ratio of 1.5 times or more in the heating zone.

[0010] The present invention also relates to a melt index (M
I) A polyolefin of 0.01 or more is melted and spun out from a spinneret, a temperature below the melting temperature (Tm) of the polyolefin just below the spinneret and in a temperature range (ΔT) at which the spun polymer does not substantially crystallize. The spun yarn is passed through the heated spinning zone held in the heating zone and guided to a heating zone downstream of the hot spinning zone while maintaining the temperature of Tm- | ΔT | or higher, and the spun yarn is heated and stretched in the heating zone. And a polyolefin-based fiber produced by a method including winding a drawn yarn using a winding means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method of the present invention can be applied to any melt-spinnable polyolefin. Such a melt-spinnable polyolefin is not particularly limited, for example, polyethylene,
Examples thereof include polypropylene, polybutene-1, a copolymer of polyethylene and polypropylene, and a binary or ternary blend polymer containing polyethylene and / or polypropylene as a main component. Usually, high density polyethylene (HDPE) is used as the polyethylene. Also,
As described above, the production method of the present invention can be applied to a polyolefin blend polymer. These polyolefins may be selected variously depending on the purpose of the fiber and the like. Further, the polymer may contain various known additives such as a heat stabilizer, an antioxidant and a lubricant.

More specifically, the melt index (M
I) The method may be applied to polyolefins of 0.01 or more. A tentative relationship between the MI of the polymer and the average molecular weight,
That is, the average molecular weight tends to be smaller as the MI of the polymer is larger, but even if the polymers have the same average molecular weight, the MI is different if the molecular weight distribution is different. When considering polyolefin spinning, it may be better to use MI rather than the average molecular weight of the polymer. Incidentally, for example, in the case of high-density polyethylene (HDPE), MI = 0.01 and the weight average molecular weight is about 200,000.

In the method of the present invention, the polyolefin is melted, the molten polymer is spun from a spinneret, passed through a heated spinning zone maintained in a high-temperature atmosphere, and the spun yarn is cooled without cooling. The spun yarn is heated and drawn in a heating zone.

The melting of the polymer and the spinning from the spinneret
It can be performed by a conventional method. The heated spinning zone immediately below the melt spinneret is maintained in a high temperature atmosphere below the melting temperature (Tm) of the polyolefin and in a temperature range (ΔT) where the spun polymer does not substantially crystallize. That is, the temperature of the heated spinning zone is Tm− | ΔT | (° C.) ≦
It can be expressed by heating spinning zone temperature <Tm (° C.).

Here, the temperature range in which the spun polymer does not substantially crystallize means that the polymer forming the spun running yarn is "heat-drawn at a high draw ratio in heat-drawing." Will only crystallize to the extent possible. ''
Means the temperature range. This temperature range (ΔT) is a value that varies depending on the type of the polyolefin used, the length of the heated spinning zone, the running speed of the spun yarn, and the like, and can be determined by those skilled in the art.

[0016] The temperature of the heated spinning zone must be lower than the melting temperature (Tm) of the polyolefin. When the temperature is higher than the melting temperature (Tm), the decomposition of the polymer is promoted, and the molecular weight is easily reduced.

The spun yarn that has passed through the heated spinning zone is guided to the heating zone while maintaining the temperature of Tm− | ΔT | or higher without cooling. If the spun yarn is cooled and solidified as in the conventional method, the crystallization of the polymer proceeds, and it becomes impossible to heat and draw at a high draw ratio. By maintaining the temperature at or above Tm− | ΔT | (° C.), the polymer is guided to the heating zone without substantially crystallizing, and heat stretching at a high stretching ratio becomes possible.

The spun yarn guided to the heating zone is stretched by heating in the heating zone. The stretching ratio does not necessarily need to be high. Depending on the type of polyolefin used and the purpose of use, it is sufficient that physical properties are practically sufficient. However, depending on the type of polymer, for example, 1.
By setting the draw ratio to 5 times or more, preferably 8 times or more, more preferably 10 times or more, or 12 times or more, more excellent physical property values are easily obtained. Such a high draw ratio cannot be achieved by the conventional method in a single-stage drawing operation directly connected to melt spinning. In order to obtain a higher draw ratio, it is preferable to consider an optimal temperature range of the heating zone. This optimal temperature range depends on the type of polymer. Subsequently, the drawn yarn is wound up.

In order to produce polyethylene fibers, in the above-mentioned method, a polyethylene having a melt index (MI) of 0.01 or more is used, and the temperature of the heated spinning zone is adjusted to a temperature lower than the melting temperature of the polyethylene and 40 ° C. or more. It is preferable that the temperature of the heating zone is maintained in the range of 40 ° C. or more and 160 ° C. or less, and the spun yarn is heated and drawn at a draw ratio of 1.5 times or more in the heating zone.

Polyethylene has a melt index (M
I) Use 0.01 or more, preferably MI:
The method is preferably applied to those having 0.1 to 30 and more preferably MI: 1 to 10.

In the production of polyethylene fibers, the temperature of the heating zone is set to 60 ° C., depending on the molecular weight and MI of polyethylene.
It is preferable to maintain the temperature in the range of at least 140 ° C.
It is more preferable that the temperature is maintained in the range of 0 ° C or more and 137 ° C or less, and it is more preferable that the temperature is maintained in the range of 100 ° C or more and 137 ° C or less.

In the case of polyethylene, the temperature of the heated spinning zone should be below the melting temperature of said polyethylene and generally of 40%.
By maintaining the temperature at a temperature of at least 40 ° C. and introducing the mixture into the heating zone while maintaining the temperature at a temperature of at least 40 ° C., substantial crystallization of the polymer can be prevented. The stretching can be performed at a high stretching ratio of at least 10 times, more preferably at least 10 times, or at least 12 times.

In order to produce polypropylene fiber, the method of the above method uses a polypropylene having a melt index (MI) of 0.01 or more, and adjusts the temperature of the heated spinning zone to a temperature lower than the melting temperature of the polypropylene and 30 ° C. or more. It is preferable to keep the temperature of the heating zone in the range of 30 ° C. or more and 190 ° C. or less, and heat-draw the spun yarn at a draw ratio of 1.5 times or more in the heating zone.

As the polypropylene, those having a melt index (MI) of 0.01 or more are preferably used.
I: 0.1 to 50, more preferably MI: 5 to 30
This method should be applied to

In the production of polypropylene fibers, the temperature of the heating zone is set to 5 depending on the molecular weight and MI of polypropylene.
The temperature is preferably maintained in the range of 0 ° C to 130 ° C, more preferably in the range of 70 ° C to 130 ° C, and even more preferably in the range of 80 ° C to 130 ° C.

In the case of polypropylene, the temperature of the heated spinning zone is maintained at a temperature lower than the melting temperature of the polypropylene and generally at a temperature of 30 ° C. or higher, and is introduced into the heating zone while maintaining the temperature at 30 ° C. or higher. Substantial crystallization of the polymer can be prevented and 1.
Stretching at a high draw ratio of 5 times or more, preferably 8 times or more, more preferably 10 times or more, or 12 times or more becomes possible.

With respect to other polyolefins, the preferred temperature of the heated spinning zone and the preferred temperature range of the heating zone vary depending on the type of the polymer, but it is preferable to select optimal conditions.

In the method of the present invention, the heated spinning zone comprises:
Although not particularly limited, it is preferable to be constituted by a spinning cylinder or a heating plate for spinning. It is also conceivable to supply hot air to this zone. However, when hot air is supplied, it is difficult to control the ambient temperature, and depending on the flow of the wind, the yarn may be cooled even in some cases.

[0029] The heating zone is provided downstream of the heated spinning zone. In order not to lower the temperature of the yarn that has passed through the heated spinning zone, the distance between the heating zone and the heated spinning zone is preferably as short as possible. For example, it is about 0 to 1000 mm, and about 200 to 1000 mm in an actual manufacturing apparatus.
Alternatively, the entire heating spinning zone and the heating zone may be covered with a heating cylinder, and both zones may be arranged continuously. In this case, the distance between both bands is substantially 0 mm.

In the method of the present invention, the heating zone may be configured so that the stretching is performed in the heating zone or between the heating zone and the winding means. Although not required, it can be constituted by a heating means such as a heat roll, a heating pin, a pin, a heating cylinder, and a heating plate.

In order to perform sufficient stretching, the heating zone may include a plurality of heating zones, for example, a first heating zone and a second heating zone. In such a case, the first heating zone may be constituted by at least one kind of heating means selected from a heat roll, a heating pin and a pin. Further, the second heating zone may be constituted by a heating cylinder or a heating plate.

In the method of the present invention, the stretching may be carried out mainly in the heating zone (mainly the first heating zone when the heating zone comprises the first zone and the second zone). Further, stretching is further performed between the heating zone and the winding means, and the total stretching ratio is preferably 10 times or more, more preferably 12 times or more.
It may be at least twice, more preferably at least 15 times. Where the stretching is performed can be changed depending on the operating conditions.

In the method of the present invention, a fiber oil (oil) is provided between the melt spinneret and the heating zone (or the second heating zone when the heating zone is composed of the first zone and the second zone).
It is preferable not to apply. When the fiber oil agent is applied, (if the heating zone includes the first zone and the second zone, the second), it is performed downstream of the heating zone, for example, immediately before winding. When a fiber oil is applied to undrawn yarn,
Since the fiber is cooled and the crystallization proceeds, it is preferable not to apply a fiber oil (oil) between the spinning step and the drawing step in order to avoid this.

Further, in the present method, (the heating zone is the first
When it is composed of a zone and a second zone, it is also possible to heat-set by tension or constant-length heat treatment between the heating zone and the winding means or after winding the drawn yarn. The tension or fixed-length heat treatment can be performed by a conventional method.

According to the production method of the present invention, a molten polymer is spun from a spinneret, passed through a heated spinning zone maintained in a high-temperature atmosphere within a specific temperature range, and cooled without cooling.
Since the spun yarn is guided to the heating zone while maintaining the temperature of m− | ΔT | (° C.) or more, and the polymer is substantially prevented from crystallizing, for example, 1.5 times or more, preferably 8 times or more in the heating zone. The film can be stretched by heating at a draw ratio of at least 10 times, more preferably at least 10 times. As a result, a polyolefin fiber having practically sufficient performance can be produced. As described above, according to the production method of the present invention, there is no need to perform two steps of spinning and drawing as in the related art, and a polyolefin fiber having practically sufficient performance with a very simple apparatus configuration and operation method. Can be manufactured. Therefore,
Cost reduction of polyolefin fibers is achieved.

Next, the present invention will be described more specifically with reference to FIG. FIG. 1 is a view schematically showing an example of a spinning and stretching apparatus for carrying out the production method of the present invention.

In FIG. 1, the melt extrusion mechanism mainly comprises an extruder (1) for supplying a molten polymer.
And a gear pump (2) for accurately controlling the discharge amount, and a spinneret (3). Immediately below the spinneret (3), as a heated spinning zone, a length of 200 to 1000 m
An air bath heating cylinder (4) of about m is provided. The heating cylinder (4) is heated by a heater (5). Heat rolls (7) and (8) are provided below the heating cylinder (4) as a first heating zone at a distance (L) of about 20 to 200 mm. The distance (L) may be, for example, about 200 to 500 mm in an actual manufacturing apparatus. Heat rolls (7) and (8) have a diameter of 20 to 150 mm.
It has a cylindrical shape of about mm and a depth of about 100 mm, and usually two pieces are used. Immediately below the heat roll (8), an air bath heating cylinder (9) having a length of about 300 to 2000 mm is provided as a second heating zone. A heating plate may be used instead of the heating cylinder. Below the heating tube (9),
A guide roll (10) is provided, and a winding machine (11) is further provided. Note that the guide roll can be appropriately arranged.

The molten polymer is spun from the spinneret (3) using the apparatus having the above-described structure, passed through a heating cylinder (4) maintained in a high-temperature atmosphere, and cooled without cooling.
(Y) is directed to heat rolls (7) and (8) to prevent substantial crystallization of the polymer. And heat roll
Between (7) and (8), or between heat rolls (7) and
Heat stretching is preferably performed at a high stretching ratio between (8) and the winder (11).

The yarn is heated with a heat roll (7) and / or
(8) may be rotated several times. Further, tension or constant-length heat treatment may be performed between the heating cylinder (9) and the winding machine (11) for heat setting, or, after the drawn yarn is wound, tension or constant-length heat treatment is performed in a separate process. And heat-fixed.

Further, in order to carry out the production method of the present invention, it is possible to use a spinning and stretching apparatus shown in FIG. That is, FIG. 2 is a diagram schematically illustrating an example of a spinning and stretching apparatus for performing the production method of the present invention.

In FIG. 2, the melt extruding mechanism constituted by the extruder (1), the gear pump (2) and the spinneret (3) is the same as that in FIG. Immediately below the spinneret (3), a heating cylinder (15) provided with a heater (16) is provided as a heating spinning zone. As a first heating zone, a heating cylinder (17) is provided continuously immediately downstream of the heating cylinder (15). The heating cylinder (17) is configured to be heated by a heater (18), and inside the heating cylinder (17), heat rollers (21) and (22)
(23) are arranged. And as a second heating zone, a heating cylinder (19) is provided continuously immediately downstream of the heating cylinder (17),
The heating cylinder (19) includes a heater (20). A guide roll (24) is arranged below the heating cylinder (19), and a winding machine (25)
Is provided.

The molten polymer is spun out from the spinneret (3) using the apparatus having the above-described structure, passed through the heating cylinder (15) maintained in a high-temperature atmosphere, and immediately introduced into the heating cylinder (17). Prevent the polymer from substantially crystallizing. Then, between the hot rollers (21) (22) (23), or between the hot rollers (21) (22) (23) and the winder (25), preferably heat-drawn at a high draw ratio. . In order to carry out the production method of the present invention, two examples of the spinning and stretching apparatus are shown, but various other spinning and stretching apparatuses can be considered.

[0043]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the examples, spinning and drawing were performed using the apparatus shown in FIG. The measurement of tensile strength, tensile modulus and elongation at break was performed according to ASTM method D3379-75 (197).
Performed according to 5).

Example 1 Production of Polyethylene Fiber High-density polyethylene pellets (melt index (M
I) = 8 g / min, using a commercially available product (manufactured by Tosoh Corporation)
Spin drawing was performed under the following conditions. 1. Spinning conditions (1) Filament winding speed: 200 to 600 m /
Minute (2) Number of filaments: 1, single yarn fineness: 14.0-2
9.9 denier (3) Polymer discharge amount: 0.1 to 0.6 g / min / hole Nozzle diameter: 1 mm (4) Temperature of gear pump (2) and spinneret (3): 240
° C (5) Heating spinning zone-heating cylinder (4) Temperature: 80 ° C, length:
400 mm (6) Distance (L): 50 mm (7) First heating stretching zone—stretching rolls (7) and (8) (both 30 mm in diameter and 70 mm in depth) Temperature of stretching rolls (7) and (8): 115 ° C. , 120 ° C,
125 ° C, 130 ° C, 135 ° C, 137 ° C, or 140
° C Surface speed of the stretching rolls (7) and (8): 10 m / min (8) Second heating stretching zone-heating cylinder (9) Temperature: 115 ° C,
120 ° C, 125 ° C, 130 ° C, 135 ° C, 137 ° C,
Or 140 ° C (same temperature as stretching rolls (7) and (8)), Length: about 500mm

2. Stretching roll (7) (8) and heating cylinder (9) Temperature and maximum stretching ratio The temperature of the stretching roll (7) (8) and heating cylinder (9) (hereinafter, both temperatures are referred to as stretching temperature) were changed. Sometimes the maximum draw ratio was the value shown in Table 1.

[0046]

[Table 1]

From Table 1, when the temperature of the heated spinning zone was set at 80 ° C. under the above conditions, a draw ratio of 10 times or more was obtained at a drawing temperature of 125 ° C. to 137 ° C. Each of the obtained filaments was observed with an electron microscope. 115 ° C to 137 ° C
The cross-sectional shape of each filament obtained at the drawing temperature was circular, and the filament surface was smooth. The filament obtained at a stretching temperature of 140 ° C. had a slightly distorted circular cross section, and lacked the smoothness of the filament surface. The stretching temperature was somewhat too high, and there were signs that fusion to the stretching roll surface had occurred. MI
Using high-density polyethylene with a little smaller than 8,
The fusion phenomenon will be less likely to occur.

3. Regarding fiber physical property values The tensile strength, tensile elastic modulus, and elongation at break of the polyethylene fiber obtained under the conditions of a drawing temperature of 135 ° C. and a draw ratio of 13.3 times were measured, and the results shown in Table 2 were obtained. Met. Physical properties sufficient for practical use were obtained. For comparison, in this example, fibers obtained in exactly the same manner except that stretching was not performed (drawing rolls (7) and (8) and a heating tube)
(9) Temperature: 135 ° C) is shown in Table 2.

[0049]

[Table 2]

Example 2 Production of Polypropylene Fiber
Polypropylene pellets (melt index (MI)
= 15 g / min, and a commercially available product (manufactured by Nippon Polychem Co., Ltd.) was used for spinning and drawing under the following conditions. 1. Spinning conditions (1) Filament winding speed: 200 to 600 m /
Minutes (2) Number of filaments: 1, single yarn fineness: 7.0 to 15.
2 denier (3) Polymer discharge amount: 0.1 to 0.6 g / min / hole Nozzle diameter: 0.5 mm (4) Temperature of gear pump (2) and spinneret (3): 230
° C (5) Heating spinning zone-heating cylinder (4) Temperature: 110 ° C, length: 400 mm (6) Distance (L): 50 mm (7) First heating stretching zone-stretching rolls (7) and (8) (Both diameter 30 mm, depth 70 mm) Temperature of stretching rolls (7) and (8): 80 ° C, 90 ° C, 10 ° C
0 ° C., 110 ° C., 120 ° C., 130 ° C., or 140 ° C. Surface speed of the stretching rolls (7) and (8): 10 m / min (8) Second heating stretching zone—heating cylinder (9) Temperature: 80 ° C. 9
0 ° C, 100 ° C, 110 ° C, 120 ° C, 130 ° C, or 140 ° C (same temperature as stretching rolls (7) and (8), respectively), length: about 500 mm

2. Stretching roll (7) (8) and heating cylinder (9) Temperature and maximum stretching ratio The temperature of the stretching roll (7) (8) and heating cylinder (9) (hereinafter, both temperatures are referred to as stretching temperature) were changed. Sometimes the maximum draw ratio was the value shown in Table 3.

[0052]

[Table 3]

From Table 3, when the temperature of the heated spinning zone was 110 ° C. under the above conditions, a draw ratio of 10 times or more was obtained at a draw temperature of 80 ° C. to 130 ° C. Each of the obtained filaments was observed with an electron microscope. Each filament obtained at a stretching temperature of 80 ° C. to 130 ° C. had a circular cross section and a smooth filament surface. The filament obtained at a stretching temperature of 140 ° C. had a slightly distorted circular cross section, and lacked the smoothness of the filament surface. The stretching temperature was somewhat too high, and there were signs that fusion to the stretching roll surface had occurred. Using high-density polyethylene whose MI is slightly smaller than 15,
The fusion phenomenon will be less likely to occur.

3. Regarding fiber physical property values The physical properties of the polypropylene fiber obtained under the conditions of stretching temperature: 100 ° C. and stretching ratio: 10.5 times were measured for the tensile strength, tensile elastic modulus and elongation at break. Met. Physical properties sufficient for practical use were obtained. For comparison, in this example, the physical property values of the fibers (drawing rolls (7) and (8) and the heating cylinder (9) temperature: 100 ° C.) obtained in exactly the same manner except that the drawing was not performed. It is shown in Table 4.

[0055]

[Table 4]

As described above, Examples 1 and 2 are examples of the production of polyethylene fibers and polypropylene fibers.
According to I, by further optimizing various conditions such as the temperature and the length of the heated spinning zone, the distance (L) between the heated spinning zone and the heating zone, and the temperature of the heating zone, higher physical property values can be obtained. A polyolefin fiber will be obtained.

The production method of the present invention can be applied to all polyolefins that can be melt-spun. Therefore, the above-described embodiment is merely an example in every aspect, and should not be construed as limiting. Furthermore, all modifications belonging to the equivalent scope of the claims are within the scope of the present invention.

[0058]

According to the method for producing a polyolefin of the present invention, as described above, the spun yarn is guided to the heating zone without substantially crystallizing the polymer, and the draw ratio is, for example, 10 times or more in the heating zone. , It is possible to produce a polyolefin fiber having practically sufficient performance. Thus, according to the production method of the present invention,
It is not necessary to perform two steps of spinning and drawing as in the related art, and a polyolefin fiber having practically sufficient performance can be produced with a very simple apparatus configuration and operation method.
Therefore, the entire manufacturing process can be shortened, and the cost of the polyolefin fiber can be reduced.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an example of a spinning and stretching apparatus for carrying out a production method of the present invention.

FIG. 2 is a view schematically showing an example of a spinning and stretching apparatus for carrying out the production method of the present invention.

[Explanation of symbols]

 (1): Extruder (2): Gear pump (3): Spinneret (4): Heating cylinder (heating spinning band) (5): Heater (L): Heating cylinder (4) and heat roll (7) Distance (7) (8): Heat roll (first heating stretching zone) (9): Heating cylinder (second heating stretching zone) (10): Guide roll (11): Winding machine (Y): Yarn

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4L035 BB36 BB52 BB77 BB78 BB89 BB91 FF01 FF02 HH10 MA01 MA10 4L045 AA05 BA03 BA60 CA29 DA15 DA17 DA42 DC02

Claims (17)

[Claims] 1. A polyolefin is melted and spun from a spinneret to a temperature below the melting temperature (Tm) of the polyolefin immediately below the spinneret and within a temperature range (ΔT) at which the spun polymer does not substantially crystallize. The spun yarn is passed through the held heated spinning zone, and the spun yarn is guided to a heating zone downstream of the hot spinning zone while maintaining the temperature of Tm- | ΔT | or higher, and the spun yarn is heated and stretched in the heating zone. A method for producing a polyolefin fiber, comprising winding a drawn yarn using a winding means. 2. The method for producing a polyolefin fiber according to claim 1, wherein the polyolefin has a melt index (MI) of 0.01 or more. 3. A polyolefin having a melt index (MI) of 0.01 or more, such as polyethylene, polypropylene, polybutene-1, a copolymer of polyethylene and polypropylene, and a binary or ternary composition containing polyethylene and / or polypropylene as a main component. 3. The method for producing a polyolefin fiber according to claim 1, wherein the method is selected from the group consisting of: 4. The method for producing a polyolefin-based fiber according to claim 1, wherein the drawing is performed at a draw ratio of 1.5 times or more in a heating zone. 5. Using polyethylene having a melt index (MI) of 0.01 or more as a polyolefin, maintaining the temperature of the heated spinning zone at a temperature lower than the melting temperature of the polyethylene and at least 40 ° C., and reducing the temperature of the heating zone. The polyolefin-based material according to any one of claims 1 to 4, wherein the spun yarn is heat-drawn at a draw ratio of 1.5 or more in a heating zone while maintaining the temperature in a range of 40C to 160C. Fiber manufacturing method. 6. The method for producing a polyolefin fiber according to claim 5, wherein the temperature of the heating zone is maintained in a range of 60 ° C. or more and less than 140 ° C. 7. Using a polypropylene having a melt index (MI) of 0.01 or more as a polyolefin, keeping the temperature of the heated spinning zone at a temperature lower than the melting temperature of the polypropylene and 30 ° C. or more, and reducing the temperature of the heating zone. 30
The polyolefin-based fiber according to any one of claims 1 to 4, wherein the spun yarn is heated and drawn at a draw ratio of 1.5 times or more in a heating zone while maintaining the temperature in a range of not less than 0 ° C and not more than 190 ° C. Manufacturing method. 8. The method for producing a polyolefin-based fiber according to claim 7, wherein the temperature of the heating zone is maintained in a range from 50 ° C. to 130 ° C. 9. The method for producing a polyolefin fiber according to claim 1, wherein the heated spinning zone is constituted by a spinning cylinder or a heating plate. 10. The method for producing a polyolefin fiber according to claim 1, wherein the heating zone comprises a first heating zone and a second heating zone. 11. The method for producing a polyolefin fiber according to claim 10, wherein the first heating zone is constituted by at least one kind of heating means selected from a heat roll, a heating pin, and a pin. 12. The method for producing a polyolefin-based fiber according to claim 10, wherein the second heating zone is constituted by a heating cylinder or a heating plate. 13. The stretching is performed mainly in a heating zone.
A method for producing the polyolefin-based fiber according to any one of claims 1 to 12. 14. The method for producing a polyolefin fiber according to any one of claims 1 to 13, wherein drawing is further performed between the heating zone and the winding means. 15. The method for producing a polyolefin fiber according to any one of claims 1 to 14, wherein a fiber oil (oil) is not applied between the melt spinneret and the heating zone. 16. The heat-fixing method according to claim 1, wherein the heat-setting can be performed by a tension or fixed-length heat treatment between the heating zone and the winding means or after winding the drawn yarn. 4. The method for producing a polyolefin fiber according to claim 1. 17. Melt index (MI) 0.01
The above-mentioned polyolefin is melted and spun out from a spinneret, and heating is performed at a temperature lower than the melting temperature (Tm) of the polyolefin just below the spinneret and in a temperature range (ΔT) at which the spun polymer does not substantially crystallize. The spun yarn is passed through the spinning zone, and the spun yarn is led to the heating zone downstream of the heating spinning zone while maintaining the temperature of Tm- | ΔT | A polyolefin-based fiber produced by a method including winding a drawn yarn.