KR100199683B1 - Spinning process for the preparation of high thermo-weldability polyolefin fibers - Google Patents

Abstract

Disclosed are polyolefin fibers, for the preparation of nonwoven fabrics, prepared by using dies having a real or equivalent output diameter of the holes greater than or equal to 0.5 mm, with the proviso that for fibers having a count greater than or equal to 4 dtex, the ratio of the said output hole diameter to the count is greater than or equal to 0.06 mm/dtex.

Description

Spinning method for the production of high thermal weldability polyolefin fibers

The present invention relates to a spinning process for producing polypropylene based fibers suitable for the production of heat weldable polyolefin fibers, in particular nonwoven fabrics.

The nonwoven fabrics are generally particularly suitable for applications requiring significant softness and tear resistance, such as for diaper covers and sanitary garments made of low count fibers of 0.2 to 5 dtex or of membranes made of fibers with a count of 3 to 10 dtex. proper. The basic requirement for nonwoven polyolefin fibers is that they must be able to be bonded to each other by the union of temperature and pressure on which the thermal calendaring process is based. This property, called thermal weldability, is not always present in polyolefin fibers, nor is it always the same degree. In principle, thermal weldability depends on the type of polyolefin being spun, the additives it contains, the type of spinning method used and the spinning conditions.

The published European patent application 391438 discloses polyolefin compositions which are suitable for spinning and are characterized by the presence of organic phosphites and / or phosphonites, stabilizers selected from hindered amine light stabilizers (HALS) and optionally phenolic antioxidants. Describe.

The patent application describes thermally weldable fibers obtained from the stabilized polyolefin composition by conventional spinning methods, in particular by staple fiber manufacturing. The good thermal weldability shown in the examples in this case is due to the choice of stabilizer. Fibers with a count of 1.9 to 2.2 dtex in this embodiment are typically 0.4 in diameter. It is manufactured using a long-spinning device (characterized by high fiber-winding speed, above all) equipped with a die having a hole of.

Small diameter (0.4) to produce low count fibers The use of dies with holes is not only for the short-spinning apparatus used for producing staple fibers, but also for both the long-spinning apparatus and spun-bonding machine, because high production rates can be obtained. Typical.

In fact, the smaller the diameter of the hole, the larger the number of holes in the die, which means more fibers per unit time. This is why the diameter of 0.40 in the manufacture of high-count fibers (more than 5 dtex) in the art There is a limitation that dies with larger holes should not be used.

Now surprisingly, for both staple fiber manufacturing and spin-bonding processes, diameter 0.5 Using a die with the above holes significantly increased thermal weldability, but found that for fibers with counts of 4 dtex or more, the ratio of hole diameter to count should be sufficiently high.

Accordingly, the present invention provides a method of producing a heat weldable fiber, preferably having a count of 0.2 to 10 dtex, more preferably 0.5 to 3 dtex, wherein the die used is 0.5 Above, especially 0.5 to 2 For fibers having an outlet diameter of, or equivalent to, a sample having a count of at least 4 dtex, the ratio of outlet diameter to count is 0.06 / dtex or more, preferably 0.08 / dtex or more, more preferably 0.1 Must be greater than / dtex

As used herein, the outlet diameter is the diameter of the hole on the outer surface of the die, ie located in front of the die from which the fibers are ejected. Inside the die, the diameter of the hole can be different from the diameter of the outlet. The corresponding outlet diameter applies when the shape of the hole is not circular, in which case it is considered for the purposes of the invention to be the diameter of an ideal circle having the same area as the area of the outlet corresponding to the corresponding diameter.

As mentioned above, the method of the present invention can be performed using long-spinning and short-spinning, and spin-bonding devices for producing staple fibers.

Long-spinning devices typically comprise a first spinning segment in which the fibers are extruded and air cooled in a quench column. Subsequently, these fibers go to the finishing stage where they are drawn, crimped, bulked and cut. In general, the finishing step is carried out in a particular area where fiber irradiation is intermittently directed to spinning into a single irradiation of a total count of 100 to 200 kilotex. The rovings are sent to drawing, crimping bulking and cutting devices which are operated continuously at spinning speeds of 100 to 200 m / min. In another form of long-spinning apparatus, the finishing step is performed following the spinning step. In this case the fibers are conveyed directly from the assembly roller to the stretching roller, where they are stretched to some extent (less than 1.5). They are then collected in an irradiation of about 5 kilotex counts and then crimped bulked and cut at a speed corresponding to the spinning speed.

In addition, the long-spinning apparatus has better control of the process parameters than the short-spinning apparatus. The process conditions generally adopted when using long-spinning devices are:

Velocity at the hole 0.2 g / min;

Fiber-set speed 500 m / min;

The area where the fiber is cooled and solidified after exiting the die 0.50m

The above conditions can also be used in the method of the present invention wherein the die in which the operation is performed using the long-spinning apparatus and used is as described above.

Preferably the operation is carried out within the following time range:

A flow rate of 0.15 to 1.0 g / min, preferably 0.2 to 0.5 g / min at the hole;

-Fiber aggregation speed 500 to 3500 m / min, preferably 600 to 2000 m / min.

Moreover, the draw ratio of 1.1-4.0 is preferable.

For further details on the long-spinning device see Friedhelm Hauser's Plastics Extrusion Technology, Hauser Press, 1988, chapter 17.

It has been found that as the fiber aggregation rate is reduced, the thermal weldability of staple fibers is improved. In particular, in the case of staple fibers, the method of the invention is particularly advantageous when a short-spinning apparatus is used, which is characterized by a low fiber aggregation speed (less than 500 m / min), among other things.

The short-spinning devices allow continuous operation because the spinning speeds correspond to the calculation, crimping and cutting speeds, and because of their simplicity and reduced total volume, these devices are more economical than long-spinning and are suitable for small scale production. . However, to date, it has not been possible to obtain staple fibers with good thermal weldability values (2.5 N or more, as measured according to the measuring method described in the Examples) with the shot-spinning apparatus. Therefore, the present invention is of particular importance when using the short-spinning apparatus, since the short-spinning apparatus can be used to produce heat weldable staple fibers.

The process conditions optimally used when using the short-spinning apparatus according to the present invention are as follows.

The flow rate in the pore is in the range of 0.005 to 0.18 g / min, preferably 0.008 to 0.070 g / min, more preferably 0.010 to 0.030 g / min. The fiber assembly speed is 30 to 500 m / min, preferably 40 to 250 m / min, more preferably 50 to 100 m / min. The draw ratio is 1.10 to 3.50, preferably 1.20 to 2.50 minutes. Further, the fiber cooling and solidifying space (cooling space) at the die exit is preferably 2 More preferably, 10 Above, especially 10 to 350 to be.

The cooling is generally induced by air jets or flow. Therefore, the cooling space is the distance between the die and the air jet or flow.

Finally, according to the invention, the stretching temperature is 100 Less than or equal to 15 To 50 It must be a range. See M. Ahmed, Polypropylene fibers science and technology, Elsevier Scientific Publishing Company (1982) pages 344-346 for more details on short-spinning devices.

The spinning temperature for the long- and short-spinning devices is generally 240 To 310 , Preferably 270 To 300 to be.

Devices used in the spin-bonding method typically include an extruder having a die on the spinning head, a cooling tower, and an air intake assembly device for using Venturi tubes.

At the bottom of this apparatus, which uses air velocity to control the fiber assembly rate, the filaments are typically collected on a conveyor belt, where the filaments are distributed to form a web for thermal welding in the calender.

According to the invention, when using a typical spin-coupler, it is convenient to use the following process conditions.

0.1 to 2.0 g / min; Preferably the flow rate in the pores in the range of 0.2 to 1.0 g / min.

After leaving the die, the space where the fibers are cooled and solidified (cooling space) is preferably 2 More preferably, 10 More than 10 to 350 to be.

The fibers are generally cooled by air jets or flow. The cooling space is the distance between the die and this air jet or flow.

Spinning temperature is generally 230 To 300 , Preferably 240 To 280 to be.

Generally, the olefin polymers that can be used in the process of the present invention to produce heat weldable fibers include polymers or copolymers of R—CH═CH ₂ (where R is a hydrogen atom or a C ₁ to C ₆ alkyl radical) and their Is a mixture of. Especially preferred are the following polymers:

1) Isotactic or mostly isotactic propylene homopolymers

2) 0.05 to 20% total comonomer content of propylene with ethylene and / or C ₄ -C ₈ alpha-olefins such as 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene Crystalline copolymers by weight or mixtures of the copolymers with isotactic or mostly isotactic propylene homopolymers;

3) one of (A) a propylene homopolymer and / or a copolymer of item 2), and (B) a copolymer of ethylene with propylene and / or a C ₄ to C ₈ alpha-olefin, optionally in small amounts A heterophasic copolymer comprising an elastomeric fraction containing a diene such as butadiene, 1,4-hexadiene, 1,5hexadiene, ethylidene-1-norbornene.

Preferably the amount of diene in (B) is 1% to 10% by weight.

The heterophasic copolymer (3) is prepared by mixing components in a molten state or by continuous copolymerization according to known methods, and generally contains the copolymer fraction (B) in an amount of 5% by weight to 80% by weight.

Particular examples of olefin polymers that are particularly suitable for making heat weldable fibers are the following propylene random copolymers:

a) crystalline propylene random copolymer containing 1.5% to 20% by weight of ethylene or C ₄ to C ₈ alpha-olefin;

b) crystalline propylene random copolymers containing 85% to 96% propylene, 1.5% to 5% ethylene, and 2.5% to 10% C ₄ -C ₈ alpha-olefins;

c) (1) 30% to 65% of a copolymer of propylene containing 80% to 98% propylene with a C ₄ to C ₈ alpha-olefin; And

(2) 35% to 70% ethylene and optionally a propylene copolymer with C ₄ to C ₈ alpha-olefins in an amount of 2% to 10%; And containing an ethylene of 0.5% to 5% when olefins are present the copolymer wherein the C ₄ ~ C ₈ alpha-if the olefin is not present containing an ethylene of from 2% to 10%, and C ₄ ~ C ₈ alpha; Crystalline propylene random copolymer composition comprising a (% by weight);

d) (1) 40% to 70% of at least one crystalline propylene copolymer in an amount of 5% to 20% of at least one comonomer selected from ethylene and / or C ₄ to C ₈ alpha-olefins;

(2) 30% to 60% LLDPE with an MFR E of 0.1-15 (according to ASTM D 1238); A composition of crystalline propylene random copolymer and crystalline ethylene copolymer comprising a.

The copolymer can also be used in admixture with each other and / or isotactic or mostly isotactic propylene homopolymer.

Another particular example of an olefin polymer that is particularly suitable for making heat weldable fibers is from 5% to 95% by weight of isotactic or mostly isotactic propylene homopolymers, and / or random propylene aerials of the types a) to b) above. A heterophasic copolymer comprising copolymer and 95% to 5% by weight of a composition selected from:

(I) a composition comprising:

(i) propylene homopolymer having 10 to 60 parts by weight of isotactic index of at least 90, or ethylene of propylene containing at least 85% by weight of propylene and having isotactic index of at least 85 and / or another C ₄ to C ₈ alpha-olefin Crystalline copolymers;

(ii) a crystalline polymer fraction containing ethylene that is insoluble in xylene at 10 to 40 parts by weight of ambient temperature;

(iii) an amorphous ethylene-propylene copolymer fraction containing 30 to 60 parts by weight of optionally minor dienes and soluble in xylene at ambient temperature and containing 40 to 70% by weight of ethylene;

(II) a composition comprising:

(i) a propylene homopolymer having an isotactic index of 10 to 50 parts by weight or greater, or a copolymer of propylene and ethylene and / or C ₄ to C ₈ alpha-olefins containing not less than 85% by weight of propylene;

(ii) an ethylene-containing copolymer fraction insoluble in xylene at an ambient temperature of 5 to 20 parts by weight;

(iii) a copolymer fraction of ethylene with propylene and / or C ₄ -C ₈ alpha-olefins containing 40 to 80 parts by weight of optionally small amounts of diene and up to 40% by weight of ethylene, the fraction being at ambient temperature Soluble in xylene and having an intrinsic viscosity of 1.5 to 4 dl / g).

The specification of C ₄ -C ₈ alpha-olefins and dienes is as described above.

In general, when used in the production of staple fibers, the olefin polymer has a melt flow rate (MFR) of 0.5 to 100 g / 10 minutes, preferably 1.5 to 35 g / 10 minutes, as measured according to ASTM D 1238-L.

When the process of the invention is used in a spin-bonding device, the olefin polymer preferably has an MFR of 5 to 25 g / 10 minutes, in particular 8 to 15 g / 10 minutes. These MFR values constitute another characteristic characteristic of the process of the present invention, because in a conventional spin-bonding process the polyolefin has an MFR of at least 25 g / 10 min.

The MFR value is obtained either directly by polymerization or by controlled degradation. For this controlled decomposition, organic peroxides are added, for example, to the spinning line or to the pre-pelletization of the olefin polymer. Olefin polymers are generally used as pellets or unextruded particles such as flakes or spheres.

The olefin polymers spun in one process of the invention are preferably stabilized with stabilizers of the type and amount described in published European Patent Application No. 391438. According to the patent application the polyolefins used for spinning contain at least one phenolic antioxidant at a concentration not optionally exceeding 0.02% by weight of at least one of the following stabilizers:

a) 0.001 to 0.5% by weight of at least one organic phosphite and / or phosphonite;

b) 0.005 to 0.5% by weight of at least one type of HALS (hindered amine light stabilizer).

The stabilizer may be added to the polyolefin by pelletization or surface coating, or may be mechanically mixed with the polyolefin.

Specific examples of phosphites are as follows:

Tris (2,4-di-t-butylphenyl) phosphite (trade name: Irgafos 168, commercially available from CIBA GEIGY); Distearyl pentaerythritol diphosphite (trade name: Weston 618, commercially available from BORG-WARNER CHEMICAL); 4,4'-butylidenebis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite ( Trade name: Mark P, commercially available from ADEKA ARGUS CHEMICAL; tris (mononoylphenyl) phosphite; bis (2,4-di-t-butyl) pentaerythritol diphosphite (trade name: Ultranox 626, commercially available from BORG-WARNER CHEMICAL).

Preferred phosphonite is detrakis (2,4-di-t-butylphenyl) 4,4-diphenylene diphosphonite (trade name: Sandostab P-EPQ, commercially available from SANDOZ).

Examples of HALS are monomeric or oligomeric compounds containing one or more substituted amines, preferably piperidine groups, in the molecule.

Specific examples of HALS containing substituted piperidine groups are compounds sold by CIVA-GEIGY under the following trademarks:

Chimassorb 944

Chimassorb 905

Tinuvin 770

Tinuvin 292

Tinuvin 622

Tinuvin 144

Spinuvex A36

And Cyasorb UV 3346 (commercially available from AMERICAN CYANAMID).

Examples of phenolic antioxidants are: tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione ( Trade name Cyanox 1790, commercially available from AMERICAN CYANAMID; Calcium ratio [monoethyl (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate]; 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione; 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene; Pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]; Octadecyl 3- (3,5-di-t-butyl-4-hydroxybenzyl) -propionate (trade names: Irganox 1425; Irganox 3114; Irganox 1330, Irganox1010, Irganox1076, commercially available from CIVA GEIGY); 2,6-dimethyl-hydroxy-4-t-butylbenzyl abietate.

The following examples are intended to illustrate the invention and not to limit the invention.

In general, in order to evaluate the heat weldability of fibers, nonwoven fabrics are made of the tested fibers by calendering under certain conditions. The tension required to tear the nonwoven fabric in parallel and transverse directions relative to calendering is then measured.

The tensile value measured in this way is considered the basis of the fiber thermal welding force.

However, this result is significantly influenced by the finish properties of the fibers (crimping, surface finish, thermosetting, etc.) and by the homogeneity of the fiber distribution across the calender. A method for avoiding this inconvenience and more directly assessing fiber thermal weldability is described below.

Samples are prepared from 0.4 meter long 400 tex irradiation (method ASTMD 1577-7) made of continuous fibers.

After twisting the irradiation eight times, the ends are connected to obtain a product in which each half of the irradiation is twisted like a rope.

Heat welding 150 The specimen was operated at a plate temperature of, using a Bruggel HSC-ETK thermal welder using 800 N clamping pressure and a 1 second welding time.

Use a dynamometer to determine the average intensity required to separate the two halves of the probe that make up each specimen at the thermal weld. The results, expressed in Newton, are obtained by averaging at least eight measured values, which represent the heat welding strength of the fibers.

The polymers used to make the fibers in the examples are as follows:

Polypropylene I

Controlled particle size distribution (average particle size 450) containing 25 weight percent 25) Mechanical mixture of propylene homopolymer with fraction soluble in xylene and 13 g / 10 min MFRL in

Additive Concentration (Weight)

Irganox 1076 0.01%

Irganox 3114 0.01%

Irganox 168 0.07%

Calcium Stearate 0.05%

The mechanical mixture is obtained by introducing components into CACCIA speed mixer model LABO 30 and then mixing for 4 minutes at 1400 rpm.

Polypropylene II

The same coarse powder as polypropylene I, or the mechanical mixture as described above in pellet form, is assembled by extrusion.

Polypropylene III

4.2% by weight of 25, with the following ingredients surface-added Fractions soluble in xylene in and 12.2 g / 10 min MFR, 2-3 Polypropylene homopolymer in the form of oval particles with a diameter of:

Additive Concentration (Weight)

Irganox 1076 0.01%

Chimassorb 994 0.02%

Sandostab P-EPQ 0.05%

Calcium Stearate 0.05%

Chimassorb 944 is HALS having the structure

[Wherein n is generally 2 to 20]

Example 1

Using polypropylene I as defined above, staple fibers are prepared on a LEONARD 25 long spinning apparatus (Costruzioni Meccaniche Leonard-Sumirago (VA)-manufactured and marketed in the Republic of Italy). The configuration of the device is as follows:

-25 With screws with diameters and length / diameter ratios of 25 and flow rates from 1 to 6 / h extruder;

-2.5 / rev. Metering pump;

Outlet diameter is 0.8 A die having 61 spherical holes;

-18-20 extruded filaments Cooling device cooled by the air jet in the transverse direction;

An assembly apparatus having a speed of -1000 to 6000 m / min;

Drawing apparatus in a steam oven.

The following process conditions are used for the spinning process;

Die temperature 280

Flow rate 0.3 g / min at the hole

Set speed 1400m / min

Elongation ratio 1.3

Stretching temperature 100

The properties of the obtained fiber are as follows.

-Single fiber count 1.7dtex

(According to ASTM D 1577-79)

-Weldability 4.1N

Comparative Example 1

The same polymer, device and conditions as in Example 1 were used, but the die had 61 spherical holes and the outlet diameter was 0.4 to be.

The properties of the obtained fiber are as follows.

-Single fiber count 1.7dtex

-Weldability 2.0N

Example 2

Using polypropylene I as defined above, staple fibers are prepared in a short-spinning apparatus having the following configuration:

-120 Single screw extruders having a diameter and a 30 length / diameter ratio;

-150 / rev. Metering pump;

Outlet diameter is 0.6 Phosphorus 3.5 A die having a spherical hole of 10 ⁴ , said hole being located in the form of a crown;

20 on a flat plane perpendicular to the fibers discharged Cooling device coaxial with die hole in crown-shaped position to release air.

The following spinning conditions are used:

Die temperature 300

Flow rate 0.018 g / min at the hole

-Distance between die and cooling airflow 5

Set speed 70m / min

Drawing temperature 80

Elongation ratio 1.4

The properties of the fibers obtained are as follows:

-Single fiber count 2.3dtex

-Weldability 6.85N

Example 3

Staple fibers were prepared using the same equipment and conditions as in Example 2, but using polypropylene III.

The properties of the fibers obtained in this way are as follows:

-Single fiber count 2.3dtex

-Weldability 6.5N

Example 4

Staple fibers were prepared using the same aggregate, apparatus, and conditions as in Example 2, but the distance between the die and cooling airflow was 15 to be.

The properties of the fibers obtained in this way are as follows:

-Single fiber count 2.3dtex

-7.6N weldability

Example 5

Staple fibers are prepared using the same polymers, apparatus, and conditions as in Example 2, but stretching is performed at ambient temperature.

The properties of the fibers obtained in this way are as follows:

-Single fiber count 2.3dtex

-Weldability 10N

Comparative Example 2

The staple fiber was prepared using an industrial apparatus consisting of the same polymer as in Example 2 and eight spinning units as described in Example 2, but the die had an outlet diameter of 0.4 Phosphorus 5.18 It has a spherical hole of 10 ⁴ . The spinning conditions are as follows:

Die temperature 285

Flow rate 0.018 g / min at the hole

-Distance between die and cooling airflow 5

Set speed 64m / min

-Stretching temperature 80

Elongation ratio 1.5

The properties of the fibers obtained in this way are as follows:

-Single fiber count 2.3dtex

-Weldability 2.35N

Comparative Example 3

Staple fibers are used using the same apparatus and conditions as in Comparative Example 2, but polypropylene III is used.

The spinning conditions are as follows:

Temperature 295

Elongation at hole 0.024 g / min

-Distance between die and cooling airflow 5

-Assembly speed 70m / min

-Stretching temperature 80

Elongation ratio 1.35

The properties of the fibers obtained in this way are as follows:

-Single fiber count 2.3dtex

Weldability 2.2N

Example 6

Using polypropylene I, the fibers were BARMAG 25mod. 2E1 / 24D radiation

Manufacture using a bonding device (manufactured and commercially available from BARMER MASHINENFABRIK A.G.). The configuration of the device is as follows:

-25 With screw with diameter and length / diameter ratio of 24 and flow rate between 0.3 and 1.2 / h extruder;

-0.6 metering pump of / rev;

Outlet diameter is 0.8 A die having 37 spherical cross-sectional holes;

-18-20 extruded fibers Cooling device cooled by the air jet in the transverse direction;

Air suction assembly using Venturi tubes with -500 ~ 4000m / min assembly speed.

The following process conditions are used for the spinning process:

Die temperature 280

Flow rate 0.6 g / min at the hole

Set speed 2700m / min

Distance to die and cooling air jet 20

The properties of the fibers obtained are as follows:

-Single fiber count 2.2dtex

-Weldability 5.4N

[Comparative Example 4]

The same polymer, apparatus and operating conditions as in Example 6 were used, but the die had an outlet diameter of 0.4 It has 37 spherical cross-section holes.

The properties of the fibers are as follows:

-Single fiber count 2.2dtex

-Weldability 2.04N

Example 7

Using Polypropylene II, fibers and nonwovens are produced using a spin-bonding pilot device (manufactured by German company LURGI). The configuration of the device is as follows:

Outlet diameter 0.9 Right angle die with 931 spherical cross-section holes.

20 acting perpendicular to the new fiber Air cooling system.

The spinning conditions are as follows:

Temperature 280

Flow rate at the holes 0.52 g / min

-Distance from die and cold air jet 30

Set speed 2300m / min

The properties of the fibers obtained under these conditions are as follows:

-Single fiber count 2.3dtex

-Weldability 6.4N

Example 8

The fibers were prepared using the same apparatus and operating conditions as in Example 6, but using Polypropylene III.

The properties of the fiber obtained are as follows:

-Single fiber count 2.2dtex

-Weldability 5.8N

[Comparative Example 5]

Fibers were produced with the same composite as in Example 8, with the same apparatus as in Example 6, but the die had an exit diameter of 0.4 It has 37 spherical cross-section holes.

The properties of the fiber obtained are as follows:

-Single fiber count 2.2dtex

-Weldability 2.1N

Claims (14)

Die used is 0.5 In the method for producing a heat weldable polyolefin fiber having an actual or equivalent outlet diameter, the ratio of the outlet diameter to the count is 0.06 for a fiber having a counter of 4 dtex or more. How should be more than / dtex. The process of claim 1 wherein the actual or equivalent outlet diameter is between 0.5 and 2 How to be. The method of claim 1 wherein the operation is performed using a long-spinning device for staple fibers. 4. The method of claim 3 wherein the flow rate in the aperture is 0.15 to 1 g / min, the fiber assembly speed is 500 to 3500 m / min and the operational ratio is 1.1 to 4.0. The method of claim 1, wherein the operation is performed using a short-spinning apparatus for staple fibers. 6. The method of claim 5 wherein the flow rate in the aperture is from 0.005 to 0.18 g / min, the fiber gathering speed is from 30 to 500 m / min and the draw ratio is from 1.10 to 3.50. The method of claim 5, wherein the cooling space is 2 Greater way. The stretching temperature used according to claim 5 is 100. Less than how. The method of claim 1, wherein the operation is performed using a spin-coupled device. 10. The method of claim 9, wherein the flow rate in the pore is between 0.1 and 2.0 g / min and the fiber aggregation rate is between 400 and 4500 m / min. The system of claim 10, wherein the cooling space is two. Greater way. The method of claim 9, wherein the olefin polymer spun has a MFR of 5-25 g / 10 min. The olefin polymer of claim 1 wherein the olefin polymer to be spun: 1) isotactic or mostly isotactic propylene homopolymer 2) the total comonomer content range of propylene and ethylene and / or C ₄ to C ₈ alpha-olefin is 0.05% by weight. Crystalline copolymers of% to 20% by weight, or mixtures of the copolymers with isotactic or mostly isotactic propylene homopolymers; 3) one of (A) a propylene homopolymer and / or a copolymer of item 2), and (B) a copolymer of ethylene with propylene and / or a C ₄ to C ₈ alpha-olefin, optionally with a small amount of diene Heterophasic copolymer comprising an elastomeric fraction containing. The method of claim 1, wherein the olefin polymer to be spun; a) 0.01 to 0.5% by weight of at least one organic phosphite and / or phosphonite; b) at least one stabilizer selected from 0.005 to 0.5% by weight of at least one HALS and optionally at least one phenolic antioxidant at a concentration not exceeding 0.02% by weight.