JPH08260233A - Production of ultrahigh-molecular weight polyolefin filament - Google Patents

Abstract

PURPOSE: To obtain a high-strength filament by spinning a ultrahigh-molecular weight polyolefin using a melt blow die of special structure without developing melt fracture, and to produce a nonwoven fabric by using the high-strength filament. CONSTITUTION: An ultrahigh-molecular weight polyolefin polymer >=500000 in viscosity-average molecular weight is spun through a spinning nozzle <=0.3mm in diameter and <=5 in the ratio L/D (L is nozzle length, D is nozzle diameter) while electing hot air of >=300 deg.C from the vicinity of the nozzle along the spun filament, and then oriented to obtain the objective high-strength filament.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a high-strength filament using an ultrahigh molecular weight polyolefin as a raw material, and more particularly to a method for producing a high-strength filament and a non-woven fabric by molding the filament using a special die. .

[0002]

2. Description of the Related Art Conventionally, a method for producing a high-strength filament from an ultra-high molecular weight polyolefin as a raw material is a method of dissolving in a solvent, forming into a yarn and ultra-drawing (solvent method, Japanese Patent Publication No. 37-9765). As a modification of the solvent method, a method of mixing and extruding with wax or the like (Japanese Patent Laid-Open No. 62-18).
2349). The solvent method is excellent in that a yarn with good performance can be obtained, but it is costly to dissolve, desolvate, and recover the solvent, and is not practical as an industrial material in terms of cost. Further, conventionally, non-woven fabrics of continuous filaments of ultrahigh molecular weight polyolefin have not been manufactured.

[0003]

To produce finer filaments than ultra high molecular weight polyolefins, fine nozzles must be used. However, since the extrusion amount is proportional to the fourth power of the nozzle diameter, the smaller the nozzle diameter, the worse the productivity. In addition, since the shear rate of extrusion is also inversely proportional to the cube of the nozzle diameter, the shear rate becomes extremely large when the nozzle diameter becomes small, causing extrusion abnormalities such as melt fracture, and high viscosity such as ultra high molecular weight polyolefin. Polymers do not allow stable operation. Another reason why it is difficult to produce fine filaments by melt spinning ultra high molecular weight polyolefin is
Since the melt tension of the filament after exiting the spinning nozzle is large, the nozzle is cut off when the draft ratio is increased, so that there is no means for producing a fine filament by increasing the draft ratio. Ultra-high molecular weight polyolefin filaments are most used as high-strength and high-modulus fibers, but conventional melt-spinning alone has a poor drawability and often does not easily attain high strength. Therefore, in ultra high molecular weight polyolefin,
There has been a demand for an invention capable of producing fine and strong filaments with high productivity and at low cost. Further, although a non-woven fabric composed of filaments of ultra-high molecular weight polyolefin which can be produced at low cost has been desired, it has not been able to be produced.

[Means for Solving the Problems]

The inventor of the present invention has conducted extensive studies to solve these problems, and has found that there are the following three reasons why conventional filaments of ultra-high molecular weight polyolefin cannot be made into high-strength filaments. First, even if melt fracture in the spinning nozzle or even if melt fracture did not occur, the surface of the filament was molecularly oriented to a higher degree than the inner surface due to the high shearing force in the nozzle, and structural illegula was generated on the surface and the inner surface of the filament. Next, the ultrahigh molecular weight polyolefin is spun at a high temperature, and the filament exiting the spinning nozzle is exposed to the atmosphere, which is lower than the temperature of the spun filament, so that the surface of the filament is crystallized and the inner surface still molten. An illegler of the structure occurs between. In this case, when the filament is drafted,
This ileggler is further increased. Thirdly, in the molten state of the ultra high molecular weight polyolefin, the molecules are entangled with each other, so that the stretching tension becomes large and the stretching tension exceeds the breaking strength at that temperature. Therefore, if the draft ratio is increased in the molten state to improve the molecular orientation, the breaking strength at the time of stretching is increased, and the breakage of stretching is eliminated, leading to high-strength stretching. However, as mentioned above, increasing the draft ratio in the normal state not only has the problem of increasing the irregularity of the structure, but also the melt tension of the ultra-high molecular weight polyolefin is large, and when the draft ratio is increased, nozzles will run out. We were unable to realize a high draft ratio due to the connection.

The present invention is based on the above consideration and relates to a method for producing a stretched filament of an ultrahigh molecular weight polyolefin polymer, and it is roughly divided into four principle inventions to overcome the above problems. No. 1 (Means A) relates to melt spinning of ultra-high molecular weight polyolefin, and invented a means for blowing hot air in the vicinity of a nozzle and performing melt spinning using a special melt blow die. The second method (Means B) was able to realize a higher shear rate in spinning by conjugate spinning or mixed spinning with a low-molecular weight heat-fluidizable substance.
The third (Means C) is to perform stretching in a state where the ultra high molecular weight polyolefin polymer is in a molten state and is not yet completely crystallized, and the stretching tension of the stretching does not reach the spinning nozzle. By doing so, it became possible to make a high-strength filament by further full-scale drawing. In No. 4 (Means D), the continuous filaments spun by the above means are accumulated on a conveyor or the like to form a continuous filament nonwoven fabric.

The present invention is melt spinning and is based on melt extrusion. This is because this method is the cheapest and has good operability. The melt extruder must be of high horsepower to enable the extrusion of ultra high molecular weight polymers. Further, it is desirable that the screw is not easily damaged. Further, an extruder capable of extruding even when mixed with a thermoplastic low-molecular substance is more desirable. The extruder type uses ultra high molecular weight polyethylene and paraffin, and also uses powdered resin, powdered additive, powdered heating fluid material, etc., so it is desirable to have a large compression ratio and to be a non-slip type. . In order to solve these problems, it is necessary to increase the L / D of the screw, use a screw with a large root, screw with both ends, and make the barrel side a rough surface. Used.

The means A makes it possible to heat only the tip of the nozzle to a high temperature with hot air in order to avoid extrusion abnormalities such as melt fracture due to the shearing force of the high-viscosity resin. There is also a method of raising the extrusion temperature by raising the temperature of the entire nozzle, but if it exceeds 300 ° C, the decomposition will become severe and the molecular weight will decrease, so it is possible to raise the temperature only for the short resin passage time at the nozzle tip. Therefore, it is suitable to perform spinning with a melt blow die (also referred to as melt blown). However, the conventional melt-blown die itself is not suitable for the spinning of the present invention.
That is, in the conventional melt-blowing die, it is necessary to produce a polymer having a high draft property with high productivity, and in order to maintain a high draft ratio while maintaining the pressure resistance of the nozzle, it is necessary to reduce the nozzle tip angle. The nozzle diameter (D) was also around 0.5 mm, and the ratio L / D, which is the ratio of the nozzle diameter to the length (L), was around 10. However, in the present invention, since it is not necessary to increase the draft ratio, the spinning conditions can be set by selecting the optimum conditions for the ultrahigh molecular weight polyolefin without being bound by the above-mentioned constraints, and as a result of earnest research, Examples The conditions for the spinning nozzle described in Section 1 have been reached.

The spinning nozzle can be used not only in a circular cross section, but also in spinning in various cross sectional shapes such as a rectangular shape, a triangular shape, a polygonal shape, a heart shape and a star shape. The value of D in L / D in this case is expressed in the form of the narrowest part. This is because that part receives the most shearing force.

[0009] In the means B, in order to eliminate the adverse effects such as melt fracture at the spinning nozzle, mixed extrusion with a heated fluid material or conjugate extrusion is also effective. This is because such a heat-flowable substance reduces the viscosity at the spinning nozzle and also reduces the shearing force. For the sake of simplicity, the term "mixing" is used here as a representative, but it is necessary that two or more polymers are well mixed, including kneading. If the degree of mixing is poor, only the ultrahigh molecular weight polyolefin polymer will be extruded in some parts, and only the heat-fluidizable substance will be extruded in some parts, failing to attain the object of the present invention. Mixing needs to be uniform even at the stage of mixing powders or pellets of raw materials. The extruder may be a single-screw extruder or a twin-screw extruder, and a vent type extruder can also be used. In order to maintain the quantitative property, it is desirable to provide a gear pump or the like immediately after the extruder for the heated fluid material. It is also an effective means to mix well after leaving the extruder or immediately before the nozzle with a static mixer or the like. The conjugate spinning is also similar to the mixing method in that it has the effect of lowering the melt viscosity, but the conjugate method does not directly affect the strength even if surface irregularities occur in the nozzle or draft. It is a part, and also a part that flows by stretching, and has an advantage that irregular influences are small.

Mixing spinning and conjugate spinning with a heat-fluidizable substance are effective in realizing a high draft ratio in addition to preventing melt fracture due to high shearing force.
In other words, the filament spun out from the nozzle prevents the heat-fluxing substance having low viscosity from moving to the surface due to the shearing force in the nozzle and the subsequent draft, and prevents the skin of the ultra-high molecular weight polyolefin from sticking to the surface. As a result, a high draft magnification can be realized. In order to achieve a high draft rate, it is useful to use a means for keeping the spun filament just below the spinning nozzle at a high temperature. The hot air blown out by the present invention is effective as a means for maintaining a high temperature just below these nozzles, but it is also effective to heat it with a heat insulating cylinder or an infrared heater.

By using the means C, although it is still in a molten state, the temperature difference between the surface and the inside is reduced, and drawing (hereinafter referred to as pre-drawing) is performed in that state, and the drawing tension does not affect the spinning section. Thus, the molecular orientation can be increased, and the drawing tension in the subsequent full-scale drawing can be increased, which enables high-magnification drawing including pre-drawing.

The spun filament is then subjected to full-scale heat drawing (hereinafter referred to as main drawing). In this main stretching, it is necessary to lengthen the stretching zone and slowly stretch. With abrupt stretching, the stretching tension increases and the probability of stretch breakage increases. As the stretching means, roller stretching, hot air stretching, hot plate stretching, hot water stretching, wire drawing, rolling and the like can be used, and it is desirable to use these stretching means in combination to perform multi-stage stretching. This stretch ratio is usually not included in a molten state draft or pre-stretch in a polymer having a normal molecular weight, but in an ultra-high molecular weight polyolefin, the stretch ratio of the toutal including those ratios is more preferable. Explain magnification and strength. The total stretch ratio of the total must be as high as possible, usually 30 times or more, preferably 50.
Double or more, more preferably 80 or more times.

In the present invention, the filaments in the spinning or pre-stretching state can be accumulated on a conveyor or the like to form a nonwoven fabric composed of continuous filaments, in addition to the direction in which the high-strength filaments are obtained by the main stretching. The heat-fluidizable substance of the present invention can also have a function as an adhesive for this nonwoven fabric.

The ultrahigh molecular weight polyolefin used in the present invention is a polymer or copolymer of olefins such as ethylene, propylene, butene, pentene and hexene.
Polymers of olefins are desirable because they can achieve high crystallinity, and high density polyethylene and polypropylene are particularly desirable. These include those obtained by copolymerizing other polymers. These ultrahigh molecular weight polyolefins preferably have a viscosity average molecular weight of 500,000 or more, more preferably 1,000,000 or more. 135 ° C for high molecular weight polyethylene
The intrinsic viscosity measured with a decalin solution is 5 dl / g or more, preferably 10 dl / g or more. The present invention
As will be described later, an ultrahigh molecular weight polyolefin having a higher molecular weight than that of the conventional method can be used by using a heat fluid material together or using a special die. The higher molecular weight has a higher potential to make the stretched yarn higher in strength and elasticity. A polymer having a low molecular weight cannot be stretched at a high ratio, and it is difficult to achieve high strength.

The substance to be blended with or coextruded with the ultra-high molecular weight polyolefin is a heat-flowable substance, and it is necessary that the viscosity is lower than that of the ultra-high molecular weight polyolefin during extrusion molding of the ultra-high molecular weight polyolefin. that is,
This is because the difficulty in extruding the ultrahigh molecular weight polyolefin is alleviated. The molecular weight is preferably 500,000 or less, and more preferably 100,000 or less. Oil or the like which is in a liquid state at room temperature becomes a solid when it is cooled. Therefore, it is included in this heated fluid substance for convenience. Examples of the heat-flowable substance used in the present invention include polyethylene such as high-density polyethylene, polypropylene, various modified polyolefins, various waxes, ethylene vinyl acetate copolymer, polyamide, polyester, unsaturated polyester, fluorine-based polymer, and silicon-based polymer. Solvents for polymers, ultra high molecular weight polyolefins such as polyethylene glycol, glycerin, or decalin. Since polyethylene glycol and glycerin are water-soluble, they have a characteristic that they can be easily removed with water by a water-cooled film forming method or the like. These heat-fluidizable substances not only alleviate the difficulty of extrusion, but also contribute to improve the surface properties of the yarn.
Properties such as dyeability and miscibility with the FRP matrix can be imparted. In addition, low molecular weight substances such as wax are removed during film formation and stretching, and are actively removed in products.

Various additives and pigments such as adhesives, antioxidants, anti-UV agents, anti-slip agents, lubricants and antistatic agents are added to these ultra-high molecular weight polyolefins and heat-fluidizable substances.
Colorants such as dyes, flame retardants and the like can be added in the same manner as in the case of normal film extrusion. Since the extrusion molding of the present invention is carried out at a particularly high temperature, oxidation of the ultrahigh molecular weight polyolefin is concerned, but by adding a large amount of an antioxidant or a heat deterioration inhibitor to this heat-fluidizable substance, the ultrahigh molecular weight Another feature of the present invention is that extrusion molding can be performed without deteriorating the properties of the polyolefin.

The high strength filament according to the present invention has a strength of 15 g / d as an ultra high molecular weight polyolefin component.
(Gram / denier) or more can be easily produced, and preferably 20 g / d or more, further 25 g / d or more. Since the strength becomes relatively smaller as the amount of the heated fluid substance increases, it is necessary to calculate by subtracting the weight of the heated fluid substance. The denier (d) of the filament is obtained by measuring the weight of a filament having a certain length and converting it into denier.
Strength is JIS L-1069, fiber length between chucks is 20
Measured at a millimeter speed of 20 mm / min.
The average value of 0 lines is used.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example in which a nozzle having one hole is used in order to clearly show an example of the embodiment of the present invention. Ultrahigh molecular weight polyolefin polymer melt 1 is quantitatively supplied to a spinning head 2 from an extruder or the like (not shown in the drawing), and a molten filament 4 is extruded from a nozzle 3. High-pressure hot air 5 is supplied to the spinning head 2 and is jetted along a filament 4 from a hole 6 near the nozzle. Even if the hot air is blown out, the infrared air heater 7 is installed just below the nozzle in order to wind the cold air around and spin the filament to be cooled. Although not shown in the figure, providing a heat insulating cylinder is also effective in preventing cooling of the filament. Spun filament 4
Is taken up by the turn roll 8 and the nip rolls 9a and 9b, and then the nip roll 9 and the turn roll 1
0 and nip rolls 11a and 11b are pre-stretched. 9a and 11a are heating rolls of constant temperature,
b and 11b are rubber rolls. The pre-stretching process is performed in the heating chamber 12 at a constant temperature. Before the pre-stretching, the filament 4 which is hardly crystallized and has a transparent feeling is completely crystallized by the pre-stretching to become the white opaque filament 13, which is guided to the winder or the next main stretching step. The heating 7 and the nip roll 9b after the pre-drawing step and the spinning may be omitted.

FIG. 2 shows a cross-section (FIG. A) and its internal structure (FIG. B) of a melt-blown die, and a large number of dies having a structure similar to a die for manufacturing a melt-blown nonwoven fabric are used. An example of spinning a filament will be shown. The die 21 extrudes a melt a of an ultrahigh molecular weight polyolefin polymer into filaments through a large number of pores 22. The hot air 23 is ejected from the slits 24 and 25 on both sides of the pores along the spinning nozzle 22. The entire die is heated by the heating block 26. Although the figure shows a flat melt blow die, a circular die may be used.

FIG. 3 shows an example of the structure for conjugate spinning from the melt-blowing-like die of FIG. 2, in which the ultrahigh molecular weight polyolefin polymer melt a is introduced from the conduit 31 and the conduits 32 and 33 are introduced. An example of a structure in which the heated fluid substance b is introduced and spinning is performed from a large number of nozzles 22 is shown.

FIG. 4 is an enlarged view of the structure of the spinning nozzle portion shown in FIGS. 2 and 3. In a normal polypropylene or polyester meltblown nonwoven fabric, the spinning nozzle diameter of the die is the draft force by high-speed air. In order to withstand this, a nozzle diameter of around 0.5 mm is used, and if it is made smaller, nozzle cutouts increase, the shot occurrence rate increases, and a good nonwoven fabric cannot be obtained. Also, the L / D of these ordinary melt blow dies is usually around 10 in consideration of the linearity of the filaments and the mechanical pressure resistance. FIGS. A and B are examples of the structure of a conventional melt blow die, where FIG. A shows a side sectional view and FIG. B shows a front sectional view. Figures A and B are typical examples of ordinary melt-blowing dies, the nozzle diameter (D) is 0.5 mm, and the ratio of nozzle length (L) to nozzle diameter (D) (L / D). Is 10, which is very unsuitable for ultra high molecular weight polyolefin polymer filament spinning. As shown in the figure, in a normal melt-blowing die, the inflow angle α of the resin on the inner surface and the ejection angle β of the air are almost the same, usually around 60 degrees. Further, the contact point of the tip of the nozzle with the jetted air is characterized by being sharply pointed. In addition, the extrusion amount per hole of the usual melt-blowing die is as small as 0.1 g / min to 1.0 g / min, and the air amount per hole is
Very high from 300 liters / min to 800 liters / min.

FIG. 5 is an example of a nozzle portion of a melt blow die suitable for the present invention, and FIG. A is a sectional view as seen from the side.
FIG. B shows a sectional view as seen from the front. In filament spinning of ultra-high molecular weight polyolefin, the draft ratio cannot be increased, and therefore, it is preferable that the spinning nozzle diameter is small in order to obtain a fine denier filament. As a result of various experiments, the nozzle diameter is 0.3 mm or less, It is preferably 0.2 mm or less, more preferably 0.1 mm or less.
It was found to be 5 millimeters or less. Further, the L / D of the nozzle of the present invention is as small as possible, less filament breakage results in a good filament, but it is difficult to set the L / D to 0.1 or less in view of the pressure resistance of the machine. Then, as a result of various experiments, it was found that L / D is preferably 5 or less, and more preferably 3 or less. In order to increase the pressure resistance of the machine, the inflow angle α of the spinning nozzle is set to 60
Is smaller than 60 degrees, the outflow angle β of air is larger than 60 degrees, and the value of β-α is set to 30 degrees or more, L /
Although the D was small, a die having pressure resistance could be obtained. In addition, even if there is a flat part (10 mm or less) or round part at the contact point with the jetted air at the tip of the nozzle, spinning of an ultra-high molecular weight polyolefin polymer with a small amount of air and a large melt tension Then, I found that there was no problem. In the spinning of the ultrahigh molecular weight polyolefin of the present invention, the extrusion rate per hole is 0.3 g / min to 2 g / min,
The air flow rate may be 200 liters / minute or less per hole, and often 30 liters / minute or less.

Examples of various conjugate-spun composite filaments using two extruders are shown in FIG. In the figure, the shaded portion in the core indicates the ultra high molecular weight polyolefin polymer. FIGS. A and B show an example of conjugate spinning with a heart-sheath structure, and the meltable fracture can be prevented by a high shearing force at the time of spinning due to the presence of the heated fluid material on the surface. Figures C, D, E and F are examples of other types of conjugated filaments suitable for producing fine denier of ultra high molecular weight polyolefin polymer filaments by removing or separating the heat flowable material. In FIG. F, the shaded area is small, so that area is shown in black.

[0024]

[Table 1]

Table 1 shows the physical properties of the filaments produced by the ordinary method as an example and a comparative example of the method for producing the high-strength filament of the ultrahigh molecular weight polyolefin spun and drawn according to the present invention. In the table, what is indicated as ultra-high resin is the ultra-high molecular weight polyolefin of the present invention, and a, b
Is shown below. a ... Ultra high molecular weight polyethylene, viscosity average molecular weight 1.1 million b ... Ultra high molecular weight polypropylene, viscosity average molecular weight 850,000 c ... Ultra high molecular weight polyethylene, viscosity average molecular weight 280,000 What was done was the heat-fluidizable substance of the present invention, and p, q, and r are shown below. The ratio of the fluidizing material to the ultra high resin is shown in percent. p ... Paraffin wax, Sanyo Chemical Co., Ltd. Sunwax 161-P antioxidant Irganox 1010 300 ppm q ... High density polyethylene, Mitsubishi Kasei ER010S r ... Modified polypropylene, Mitsubishi Kasei Co., Ltd. The outline of the 390P spinning device is shown in the figure. The resin temperature indicates the resin temperature in the die. Draft magnification is rolls 8 and 9 in Figure 1.
Roll speed divided by the filament spinning speed.

Example 1 is a case where ultra-high molecular weight polyethylene was spun and stretched by the spinning device shown in FIG. The spinning nozzle diameter was 0.3 mm and the L / D was 1. Although the drawing process is not shown in the drawing, it can be drawn in three stages at 150 ° C. in a free space and can be drawn a total of 38 times, and the strength is about 19 g / d. Example 2 is a case in which pre-stretching is added to Example 1, and it can be stretched 75 times in total, and the strength is about 26 g / d. In Example 3, the same ultrahigh molecular weight polyethylene powder as in Example 1 was mixed with 15 paraffin wax powder having a melting point of 55 ° C.
% Mixed and fed from the hopper. Although the spinning method and the like are the same, spinning can be performed without causing melt fracture even if the extrusion amount is about 7 times larger than in Example 1. During the spinning and drawing process, the wax is gradually bleeded out of the ultra high molecular weight polyethylene system. Examples 4 and 5 are examples of conjugate spinning with ultra-high molecular weight polyethylene and ultra-high molecular weight polypropylene in the spinning device of FIGS. 3 and 5.

Comparative Example 1 is the same as Example 1, but in the case of resin c having a low molecular weight, the stretch ratio and the tensile strength after stretching are low. Comparative Example 2 is a case where the same ultra-high molecular weight polyethylene as in Example 1 was used, but no hot air was used, and also the towal ratio was low and the tensile strength was low.

Although not shown in the table, as Example 6,
Spin a number of filaments as in Example 4,
It was collected on a continuously running conveyor and bonded by an embossing roll to give a non-woven fabric.

[0029]

EFFECTS OF THE INVENTION According to the present invention, an ultrahigh molecular weight polyolefin can be spun without causing melt fracture, and can be drawn at a high draw ratio to form a high strength filament. Furthermore, by blending or co-extruding a heat-fluidizable substance, the melt fracture in the die can be reduced, and ultra-high molecular weight polyolefin with a higher molecular weight than before can be formed into a film, and higher strength and higher elastic modulus are possible. You can The addition of the heat-fluidizable substance also serves to improve the surface properties of the product yarn. Specifically, the adhesiveness, colorability, dyeability, weather resistance, slip resistance and the like can be improved. By adding a large amount of an antioxidant or a heat deterioration inhibitor to this heat-fluidizable substance, there is also an effect of enabling extrusion molding without deteriorating the properties of the ultrahigh molecular weight polyolefin. Finer filaments can be produced by mixing and conjugate spinning of heat-fluidizable substances. Finer filaments promise higher quality and are an important factor in industrial fiber.

The high-strength filament of the present invention is a ply-twisted yarn and can be processed into various ropes and the like, and can also be processed into woven fabric, biaxially and triaxially-woven weft laminated nonwoven fabric, unidirectional prepreg, etc. Construction / civil engineering sheets, FRTP, F
Used as various reinforcing materials such as RP, radar dome, and concrete reinforcement. The nonwoven fabric comprising filaments of ultra-high molecular weight polyolefin according to the present invention utilizes the properties of ultra-high molecular weight polyolefin such as slipperiness, abrasion resistance, chemical resistance, dielectric properties, and high frequency properties, and is used as a filter, mechanical parts, electronic parts. It can be applied to etc.

[Brief description of drawings]

FIG. 1 shows a conceptual diagram of a one-cone spinning device.

FIG. 2 shows a structure of a spinning device using a melt blow die, FIG. A shows a sectional view, and FIG. B shows a partially exploded view.

FIG. 3 shows an example of a melt blow die that can be conjugate spun from two polymers.

FIG. 4 shows an example of a structure of a tip nozzle portion of a normal melt blow die, FIG. A showing a side sectional view, and FIG. B showing a front sectional view.

FIG. 5 shows an example of the structure of the tip nozzle portion of the melt blow die of the present invention, FIG. A showing a side sectional view, and FIG. B showing a front sectional view.

FIG. 6 shows an example of a conjugate filament according to the present invention.

[Explanation of symbols]

1: Ultra high molecular weight polyolefin melt 2: Spinning head 3:
Nozzle, 4: Spinning filament, 5: Hot air, 6: Hot air nozzle, 7: Infrared heater, 8: Turn roll, 9: Nip roll, 10: Turn roll, 11: Nip roll,
12: hot air chamber, 13: spin-solidified filament, 21: melt blow die, 22: nozzle, 23: hot air, 24:
Hot air nozzle.

Claims (5)

[Claims] 1. An ultrahigh molecular weight polyolefin polymer having a viscosity average molecular weight of 500,000 or more, a spinning nozzle having a nozzle diameter of 0.3 mm or less, and a nozzle length (L) thereof.
And a nozzle diameter (D) ratio (L / D) is 5 or less, and a hot air of 300 ° C. or more is ejected from the vicinity of the nozzle along a spinning filament to spin the fiber, and the fiber is further stretched after spinning. To produce high strength ultra high molecular weight polyolefin filaments. 2. A method for producing an ultra-high molecular weight polyolefin filament by co-extruding a heat-flowable substance having a molecular weight of 500,000 or less through a nozzle into the surface layer of the filament when forming the ultra-high molecular weight polyolefin filament according to claim 1. 3. A method for producing an ultra-high molecular weight polyolefin filament, which comprises forming a filament by mixing a heat-flowable substance having a molecular weight of 500,000 or less and extruding it from a nozzle when forming the ultra-high molecular weight polyolefin filament according to claim 1. . 4. When forming a filament of the ultra-high molecular weight polyolefin according to any one of claims 1, 2 and 3, after the spinning filament is taken up by a roll and the spinning filament still in a molten state is stretched at least 1.5 times or more, A method for producing ultra-high-molecular-weight polyolefin filaments that are permanently stretched in the solid state. 5. A method for producing a non-woven fabric comprising continuous filaments of ultra-high molecular weight polyolefin by accumulating spun filaments according to any one of claims 1, 2, 3, and 4.