JP2849042B2 - Spinning method for producing polyolefin fiber having high heat weldability - 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

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a spinning method for producing a heat-weldable polyolefin fiber, particularly a polypropylene-based fiber, which is suitable for producing a nonwoven fabric. The nonwoven fabric is generally 0.2 to
Requires very high flexibility and tear resistance, as is the case with diaper and sanitary covering materials made from 5 dtex low count fibers or thin films made from 3 to 10 dtex count fibers It is particularly suitable for the intended use. The basic requirement for polyolefin fibers for nonwoven fabrics is that the fibers must be joined together by the co-action of temperature and pressure during hot calendering. This property, called "heat weldability," is not always present, or at least not to the same extent, in polyolefin fibers. In fact, the heat weldability basically depends on the type of polyolefin to be spun, the additives contained in the polyolefin, the type of production method, and the spinning conditions used.

Published European Patent Application No. 391438 is suitable for spinning and uses organic phosphites and / or phosphonite, HALS (Hindered Amine).
Disclosed are polyolefin compositions characterized by the presence of stabilizers selected from Light Stabilizers) and, optionally, phenolic antioxidants. The patent application describes heat-weldable fibers obtainable from the stabilized polyolefin composition by conventional spinning methods, in particular staple fiber manufacturing methods. In this case, the good thermal weldability levels shown in the examples are due to the choice of stabilizer. In the above embodiment, 1.9 to 2.2 dtex
The fibers with a count of are typical "long-spinning" devices with a die having a hole of 0.4 mm diameter (in particular,
Characterized by a high fiber take-up speed).

[0003] The use of dies with holes of small diameter (less than 0.4 mm) to produce low count fibers,
The above long-spinning equipment, as well as "short-spinning" equipment, and spun-bonding, both used in the manufacture of staple fibers
This is common because high productivity can be obtained for machines. fact,
The smaller the hole diameter, the more holes in the die and the more fibers per unit time. For this reason, in this area the use of dies with holes with a diameter of more than 0.4 mm,
Limited to the production of high count fibers (greater than 5 dtex).

[0004] Surprisingly, in both the manufacture of staple fibers and in the spun-bonding process, the use of dies with holes with a diameter of more than 0.5 mm allows for fibers with a count greater than 4 dtex. It has been found that under the condition that the ratio of the hole diameter to the number is sufficiently high, the heat weldability of the fiber is significantly increased.
Therefore, in the present invention, the count is preferably 0.2 to 10 dte
x, more preferably 0.5 to 3 dtex, wherein the die used has a true or corresponding exit hole diameter of 0.5 mm or more, especially 0.5 to 2 mm. However, for fibers having a count of 4 dtex or more, the ratio of the exit hole diameter to the count is 0.06 mm / dte.
x or more, preferably 0.08 mm / dtex or more, more preferably 0.1 mm / dtex or more.

[0005] As used herein, "exit hole diameter" means the diameter of the hole at the outer surface of the die, ie, at the die surface where the fibers exit. Inside the thickness of the die, the diameter of the hole may be different from the diameter at the outlet. Further, "equivalent exit hole diameter" applies when the hole is not circular, in which case for the purposes of the present invention consider the diameter of an ideal circle having an area equal to the area of the exit hole, It means this diameter. As mentioned earlier, the method of the present invention can be performed using long-spinning and short-spinning equipment for producing staple fibers, and spun-bonding equipment.

[0006] Long-spinning equipment usually includes a first spinning zone where the fibers are extruded and air cooled in a quench column. Subsequently, the fibers proceed to a finishing step, during which they are stretched, crimped, and cut. Generally, the above finishing step is carried out intermittently with the spinning in a special zone, where the fiber rovings are collected in a single roving having a total count of 100 to 200 kilotex. The roving is then sent to a device which is continuously operated at a spinning speed of 100-200 m / min, stretched, crimped-bulked and cut. In another type of long-spinning apparatus, the finishing step is performed continuously with the spinning step. In this case, the fiber proceeds directly from the collecting roller to the drawing roller, where the fiber is drawn at a rather subdued speed (not more than 1.5). Subsequently, the fibers are collected in a roving of a count of about 5 kilotex and then subjected to a crimping-bulking process and cut at the same speed as the spinning.

In addition, the long-spinning apparatus has better controllability of process conditions than the short-spinning apparatus. Typical process conditions when using a long-spinning device are:-hole flow rate> 0.2 g / min;-fiber accumulation speed ≥ 500 m / min;-space where the fibers are cooled and solidified after exiting the die>
0.50 m 2. The above conditions can be applied to the method of the present invention if the operation is performed by a long-spinning apparatus and the die used is the above die. Preferably, the operation is performed within the following time range. -Hole flow rate 0.15 to 1.0 g / min, preferably 0.2 to
0.5 g / min-fiber accumulation speed 500-3500 m / min, preferably 6
00 to 2000 m / min. Further, the stretching ratio is preferably 1.1 to 4.0. For additional details on long-spinning equipment, see Friedhelm Hauser, “Plastics Extrusion Technolog.
y ”, Hauser Publishers, 1988, chapter 17.

[0008] It has been found that the heat weldability of staple fibers improves as the rate of fiber accumulation decreases. In particular, in the case of staple fibers, the method according to the invention is particularly advantageous, especially when using short-spinning equipment with a low fiber accumulation speed (less than 500 m / min).
The above-mentioned short-spinning apparatus has a spinning speed of drawing,
These devices are more economical than long-spinning devices and are suitable for small-scale production because they are compatible with crimping and cutting speeds, permit continuous operation, are simple and have a small overall volume. However, hitherto, staple fibers having good thermal weldability values (e.g., greater than 2.5 N according to the measuring method described in the examples) have not been obtained with short-spinning devices. Accordingly, the method of the present invention is particularly important when using a short-spinning apparatus, as it solves the problem of producing staple fibers that can be heat welded even when working with a short-spinning apparatus.

The process conditions most suitable for using the short-spinning apparatus according to the present invention are as follows. The hole flow rate is 0.005 to 0.18 g / min, preferably 0.008 to 0.070 g / min, and more preferably 0.01 to 0.18 g / min.
0 to 0.030 g / min. Fiber accumulation speed is 30-50
0 m / min, preferably 40 to 250 m / min, more preferably 50 to 100 m / min. Stretch ratio is 1.10-3.5
0, preferably 1.20 to 2.50. Furthermore, the space for cooling and solidifying the fibers at the exit of the die is preferably more than 2 mm, more preferably more than 10 mm, especially 10 to 350 mm. The cooling is generally performed by injection or flow of air. Thus, the cooling space is the distance between the die and the jet or flow of air described above. Finally, in the present invention, the stretching temperature is preferably 10
It should be below 0C, especially between 15 and 50C. For other details of short-spinning equipment, see M.
Ahmed, “Polypropylene fibers science and technol
ogy ”, Elsevier Scientific Publishing Company (198
2) See pages 344-346. The spinning temperature in the long-spinning and short-spinning apparatuses is generally 240
C. to 310.degree. C., preferably 270.degree. C. to 300.degree.

[0010] The equipment used for the spun-bonding process is usually an extruder equipped with a die on a spinning head, a cooling tower,
And an air suction accumulator using a Venturi tube. Under this apparatus, which uses air velocities to control the fiber accumulation rate, the filaments are usually collected on a conveyor belt where the fibers are dispersed and form a web for heat welding in a calender. In the present invention, when using a typical spun-bonding machine, it is advantageous to use the following process conditions. The hole flow rate is 0.1-2.
0 g / min, preferably 0.2 to 1.0 g / min. A space where the fibers are cooled and solidified after leaving the die (cooling space)
Is preferably more than 2 mm, more preferably more than 10 mm, especially 10 to 350 mm. The fibers are generally cooled by a jet or stream of air. Thus, the cooling space is the distance between the die and the jet or flow of air described above. The spinning temperature is generally between 230C and 300C, preferably between 240C and 280C.

Generally, the olefin polymers which can be used in the process of the present invention for producing heat-weldable fibers include R-CH = C wherein R is a hydrogen atom or a C ₁ -C ₆ alkyl group.
H ₂ olefin polymers or copolymers, and mixtures thereof. Particularly preferred are the following polymers. 1) isotactic or predominantly isotactic propylene homopolymer; 2) propylene with a total comonomer content of 0.05 to 20% by weight, ethylene and / or 1-butene, 1-hexene , 1-octene, 4-methyl-1 crystalline copolymer of C ₄ -C ₈ alpha-olefins such as pentenes, or the copolymer and isotactic or mainly isotactic propylene homopolymer 3) (A) a propylene homopolymer and / or one of the copolymers of 2), and (B) a copolymer of ethylene with propylene and / or a C ₄ -C ₈ α-olefin. Optionally butadiene, 1,4-hexadiene,
A heterophasic copolymer comprising an elastomeric fraction containing a small amount of a diene such as 1,5-hexadiene, ethylidene-1-norbornene. The amount of diene in (B) is preferably from 1 to 1
0% by weight. The heterophasic copolymer (3) is prepared by mixing the components in a molten state or by sequential copolymerization by a known method, and generally prepares the copolymer fraction (B) by 5 to 80% by weight. Include in quantity.

Examples of olefin polymers particularly suitable for the production of heat-weldable fibers are the following propylene random copolymers. a) 1.5-20% by weight of ethylene or C ₄ -C ₈ α
A crystalline propylene random copolymer containing olefins, b) 85-96% by weight of propylene, 1.5-5% by weight
Of ethylene, and 2.5-10% by weight of C ₄ -C ₈ α
A crystalline propylene random copolymer containing olefins, c) (in% by weight) (1) a copolymer of propylene and a C ₄ -C ₈ α-olefin 3 containing 80% to 98% of propylene 3
0% to 65%, and (2) a copolymer of propylene with ethylene and optionally 2% to 10% of C ₄ -C ₈ alpha-olefin, not C ₄ -C ₈ alpha-olefin of the above are present Containing 2% to 10% of ethylene, C ₄
0.5% to 5% when C ₈ α-olefin is present
A) a crystalline propylene random copolymer composition comprising 35% to 75% of a copolymer containing ethylene; d) a composition of a crystalline propylene random copolymer and a crystalline ethylene copolymer, wherein In) (1)
And propylene, ethylene and / or C ₄ -C ₈ alpha 1 or more comonomers selected from olefins, the comonomer content is 5% to 20%, 40% of one or more crystalline copolymer 70 %, (2) MFR E (ASTM
LLDP with D 1238) of from 0.1 to 15
E. A composition comprising 30% to 60%. The abovementioned copolymers can also be used in a mixture with one another and / or with the isotactic or predominantly isotactic propylene homopolymer.

Other examples of olefin polymers which are particularly suitable for the production of heat-weldable fibers are 5-95% by weight of isotactic or predominantly isotactic propylene homopolymer and / or A) random copolymers of the type (a) to (d) and 95 to 5% by weight of (I) (i) a propylene homopolymer having an isotactic index of more than 90 or propylene of more than 85% by weight, Propylene and ethylene and / or other C ₄ with a tactic index greater than 85
Crystalline copolymers -C ₈ alpha-olefin, 10 to 60 parts by weight, (ii) insoluble in xylene at ambient temperature, crystalline polymer fraction 10 to 40 parts by weight containing ethylene, in xylene at (iii) room temperature A composition comprising 30 to 60 parts by weight of an amorphous ethylene-propylene copolymer fraction which is soluble and contains 40 to 70% by weight of ethylene, optionally containing a small amount of diene; (II) (i) isotactic A propylene homopolymer having an index of more than 80 or propylene and ethylene and / or C containing more than 85% by weight of propylene
₄ -C ₈ alpha olefin copolymers, 10 to 50 parts by weight,
(ii) insoluble in xylene at room temperature, 5 to 20 parts by weight of a copolymer fraction containing ethylene, (iii) soluble in xylene at room temperature,
Copolymer fraction of ethylene and propylene and / or C ₄ -C ₈ α-olefin having an intrinsic viscosity of 1.5 to 4 dl / g, an ethylene content of less than 40% by weight and optionally containing a small amount of diene. A heterophasic copolymer consisting of a composition selected from compositions containing 40 to 80 parts by weight. Examples of C ₄ -C ₈ α-olefins and dienes are described above.

Generally, when used in the manufacture of staple fibers, the olefin polymer described above is an ASTM
The melt flow rate (MFR) measured according to D 1238-L is 0.5 to 100 g / 10 min, preferably 1.
5-35 g / 10 min. According to the method of the present invention,
When used in a bonding apparatus, the above olefin polymer has an MFR value of preferably 5 to 25 g / 10 min, especially 8
１５15 g / 10 min. These MFR values are another distinctive feature of the process of the present invention, since the MFR of polyolefins in conventional spun-bonding processes is greater than 25 g / 10 minutes. The above MFR values are obtained either directly during polymerization or by controlled degradation. In order to carry out the controlled decomposition, for example, an organic peroxide is added to the spinning line or in the preceding step of pelletizing the olefin polymer. The olefin polymer is generally used in the form of pellets or non-extruded particles, for example, flakes or spheres.

[0015] Preferably, the olefin polymer spun by any of the methods of the present invention is stabilized with stabilizers of the type and amount described in published European Patent Application 391438. According to the patent application, the polyolefin for spinning comprises one or more of the following stabilizers: a) one or more phosphites and / or phosphonite, 0.01 to 0.5% by weight; b) one or more HALS (Hindered Amine Light Stabil)
izer) 0.005 to 0.5% by weight and optionally one or more phenolic antioxidants in a concentration not exceeding 0.02% by weight. The above stabilizers can be added to the polyolefin by pelletization or surface coating, or can be mechanically mixed with the polyolefin.

Examples of phosphites are available from CIBA GEIGY
Tris (2,4-di-tert-butylphenyl) phosphite, commercially available under the trademark Irgafos 168, BORG-WAR
ADEKA AR, distearyl pentaerythritol diphosphite, commercially available from NER CHEMICAL under the trademark Weston 618
4,4'-Butylidenebis (3-methyl-6-ter phosphite, commercially available from GUSCHEMICAL under the trademark Mark P
t-butylphenyl-di-tridecyl), tris phosphite (monononylphenyl), from BORG-WARNER CHEMICAL
Bis (2,4-di-tert-butyl) pentaerythritol, commercially available under the trademark Ultranox 626. Examples of preferred organic phosphonates include Sa
Tetrakis (2,4-tert-butylphenyl) diphosphonate 4,4-diphenylene, commercially available as Sandostab P-EPQ from ndoz.

HALS are monomeric or oligomeric compounds containing one or more substituted amine, preferably piperidine, groups in the molecule. HAL containing substituted piperidine group
Examples of S include Chimassorb 944, Chim, commercially available from CIBA-GEIGY.
assorb 905, Tinuvin 770, Tinuvin 992, Tinuvin 62
2, Tinuvin 144, Spinuvex A36, and American CYA
Commercially available from NAMIDE under the trademark Cyasorb UV 3346.

Examples of phenolic antioxidants include American
Commercially available Tris (4) from CYANAMIDE under the trademark Cyanox 1790
-T-butyl-3-hydroxy-2,6-dimethylbenzyl) -s-triazine-2,4,6- (1H, 3H,
5H) -trione and Irganox 14 from CIBA-GEIGY, respectively.
25, Irganox 3114, Irganox 1330, Irganox 1010, Irga
calcium bi [monoethyl (3,5-di-tert-butyl-4-hydroxybenzyl) phosphonate], 1,3,5-tris (3
5-di-tert-butyl-4-hydroxybenzyl)-
s-Triazine-2,4,6- (1H, 3H, 5H) trione, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) Benzene, pentaerythrityl-tetrakis [3
-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl 3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate], 2,6-dimethyl-3-abietic acid
Hydroxy 4-tert-butylbenzyl.

The following examples are intended to illustrate, but not limit, the invention. Evaluation of heat weldability of fiber In general, in order to evaluate the heat weldability of a fiber, a nonwoven fabric is produced from a test fiber by calendering under certain conditions. Then, the strength required to tear the nonwoven in a direction parallel to and transverse to the direction of calendering is measured. The strength value measured in this way is considered a measure of the heat welding capacity of the fiber. However, the results obtained depend on the fiber finish (crimp, surface finish, thermosetting,
) And the homogeneity of the distribution of fibers entering the calender. To avoid these inconveniences and to more directly evaluate the thermal welding properties of the fibers, the following method was developed. A 400 tex roving consisting of continuous fibers (Method ASTM D 1577-
7) Prepare a sample from 0.4 meters in length. After twisting the roving 80 times, both ends are joined together to obtain a product in which half of the roving is intertwined like one rope. The sample is subjected to heat welding using a Bruggel HSC-ETK heat welding machine at a plate temperature of 150 ° C., a clamping pressure of 800 N, and a welding time of 1 second. Using a dynamometer,
In the heat-welded area, the average strength required to separate the halves of the roving comprising each sample is measured. The result obtained by averaging at least eight measurements is expressed in Newton, and is defined as the heat weld strength of the fiber.

[0020]Spinning polymer The polymers used in the production of the fibers in the examples are as follows:
is there.Polypropylene I MFRL 13g / 10min, soluble in xylene at 25 ℃
With a controlled particle size distribution of 3.5% by weight
Flakes (average particle diameter 450μm)
A mechanical mixture of homopolymers,Additive concentrationContains (by weight) Irganox 1076 0.01% Irganox 3114 0.01% Irgafos 168 0.07% Calcium stearate 0.05%. The mechanical mixture uses CACCIA speed
Place in a mixer model LABO 30 and mix at 1400 rpm for 4 minutes
Obtained by combining.Polypropylene II Has the same composition as polypropylene I, but the mechanical
It is in the form of pellets obtained by granulating the mixture by extrusion.Polypropylene III In the form of spherical particles having a diameter of 2-3 mm, the MFR is 12.2 g /
4.2% by weight of fraction soluble in xylene at 25 ° C for 10 minutes
Is a propylene homopolymer that is Additive Concentration (by weight) Irganox 1076 0.01% Chimassorb 994 0.02% Sandostab P-EPQ 0.05% Contains calcium stearate 0.05%. Chimassorb 944 is the formula

Embedded image HALS wherein n is generally 2-20.

COMPARATIVE EXAMPLE 1 Using the above polypropylene I, Costruzio
ni Meccaniche Leonard-Sum
irago (VA)-Produce staple fibers on a LEONARD 25 long-spinning apparatus, commercially available and manufactured by Italy. The mechanism of the device is as follows. A diameter of 25 mm, a length / diameter ratio of 25, and a flow rate of 1 to
Extruder with a screw of ^{6kg / h - 2.5cm 3 / rev} . -A die with 61 holes with an outlet diameter of 0.8 mm-a cooling mechanism for the extruded filaments by means of a transverse air jet at a temperature of 18 to 20 ° C-a winding device at a speed of 1000 to 6000 m / min-steam Drawing apparatus in furnace The following process conditions are used for the spinning operation. -Die temperature 280 ° C-Hole flow rate 0.3g / min-Accumulation speed 1400m / min-Stretching ratio 1.3-Stretching temperature 100C The properties of the fiber thus obtained are:-Single fiber count 1.7dtex (ASTM D 1577-79)-Weldability 4.1N

[0022]

Example 1 Using the above polypropylene I, a staple fiber is produced using a short-spinning pilot apparatus having the following mechanism. - diameter 120 mm, a length of 30 times the diameter single - screw extruder - 150 cm ³ / rev. Metering pump-with 3.5 × 10 ⁴ round holes with an outlet diameter of 0.6 mm, the holes being located in the form of a crown-coaxial with the crown of the die hole and perpendicular to the fibers to be emitted Cooling mechanism for releasing air at 20 ° C. onto the surface The spinning conditions are as follows. -Temperature 300 ° C-Hole flow 0.018 g / min-Distance between die and cooling air flow 5 mm-Accumulation speed 70 m / min-Stretching temperature 80 ° C-Stretching ratio 1.4 The properties of the fiber thus obtained are: Fiber count 2.3dtex-weldability 6.85N

Example 2 A staple fiber is produced using the same equipment and conditions as in Example 1, but using polypropylene III. The properties of the fibers obtained in this way are: monofilament count 2.3 dtex-weldability 6.5 N

Example 3 Staple fibers are produced using the same polymers, equipment and conditions as in Example 1, but with a 15 mm gap between the die and the cooling air flow. The properties of the fibers obtained in this way are:-monofilament count 2.3 dtex-weldability 7.6 N

Example 4 A staple fiber is produced using the same polymer, equipment and conditions as in Example 1, but drawing is carried out at room temperature. The properties of the fibers obtained in this way are:-Single fiber count 2.3 dtex-Weldability 10N

Comparative Example 2 A staple fiber was produced using the same polymer as in Example 1 and an industrial apparatus consisting of eight spinning apparatuses equivalent to that of Example 1, except that the die of the apparatus had an outlet diameter of 0. .4mm
5.18 × 10 ⁴ round holes. The spinning conditions are as follows. Temperature 285 ° C. hole flow rate 0.018 g / min distance between die and cooling air flow 5 mm stacking speed 64 m / min drawing temperature 80 ° C. drawing ratio 1.5 The properties of the fiber thus obtained are: Fiber count 2.3dtex-weldability 2.35N

Comparative Example 3 Staple fibers are produced using the same equipment and conditions as Comparative Example 2, but using polypropylene III. The spinning conditions are as follows. -Temperature 295 ° C-Hole flow rate 0.024g / min-Distance between die and cooling air flow 5mm-Accumulation speed 70m / min-Stretching temperature 80 ° C-Stretching ratio 1.35 The properties of the fiber thus obtained are-single Fiber count 2.3 dtex-weldability 2.2N

EXAMPLE 5 A BARMER MASHI using polypropylene I
NENFABRIKA. G. FIG. BARMAG 25 mod., A spun-bonding apparatus manufactured and sold by Manufacture. Fabricate the fiber using 2E1 / 24D. The mechanism of the device is as follows. A diameter of 25 mm, a length / diameter ratio of 25 and a flow rate of 0.
Extruder with a screw of ^{3~1.2kg / h - 0.6cm 3 / rev} . -A die with 37 round holes with an outlet hole diameter of 0.8 mm-a cooling mechanism for the extruded fibers by means of a transverse air jet at a temperature of 18-20 [deg.] C-an integration speed of 500-using a Venturi tube 400
Air suction type accumulator at 0 m / min The spinning process conditions are as follows. -Die temperature 280 ° C-Hole flow rate 0.6 g / min-Accumulation speed 2700 m / min-Die-to-cooling air jet spacing 20 mm The properties of the fibers obtained are as follows. -Single fiber count 2.2 dtex-Weldability 5.4 N

Comparative Example 4 Using the same polymer, equipment and operating conditions as in Example 5, but the die is provided with 37 round holes with an outlet hole diameter of 0.4 mm. The properties of the obtained fiber are as follows. -Single fiber count 2.2 dtex-Weldability 2.04N

Example 6 Using polypropylene II, the German company LURGI
Fibers and non-woven fabrics are manufactured with a pilot device for spun-bonding manufactured by the Company. The mechanism of the device is as follows. -A rectangular die with 931 round holes with an exit hole diameter of 0.9 mm-acting on a plane perpendicular to the fibers to be discharged, 20
° C air cooling device The spinning process conditions are as follows. -Temperature 280 ° C-Hole flow rate 0.52 g / min-Spacing between die and cooling air flow 30 mm-Accumulation speed 2300 m / min The properties of the obtained fibers are as follows. -Single fiber count 2.3 dtex-Weldability 6.4 N

Example 7 A fiber is produced using the same equipment and working conditions as in Example 5, but using polypropylene III. The properties of the fibers obtained in this way are: monofilament count 2.2 dtex-weldability 5.8 N

Comparative Example 5 Fibers are produced using the same polymer as in Example 7 and the same equipment as in Example 5, except that the die has an exit hole diameter of 0.4 m.
Includes 37 round holes. The properties of the fibers obtained in this way are: monofilament count 2.2 dtex-weldability 2.1 N

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI D04H 1/54 D04H 1/54 C (72) Inventor Leonardo, Pinocca Italy Terni, Narni, Via, Santa, Croce, 1 ( 56) References JP-A-57-5913 (JP, A) JP-A-61-239011 (JP, A) JP-A-58-144113 (JP, A) JP-A-62-282014 (JP, A) 52-47045 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) D01F 1/00-13/04 D01D 1/00-13/02 D04H 1/00-18/00

Claims (18)

(57) [Claims] 1. A process for the production of heat-weldable polyolefin fibers, comprising operating at a fiber accumulating speed of 40 to 250 m / min using a short-spinning apparatus for staple fibers, the true or equivalent of the die used. The exit hole diameter is 0.5 mm or more, provided that the ratio of the exit hole diameter to the number is 0.06 mm / dtex or more for fibers having a count of 4 dtex or more, and the olefin polymer to be spun is 1) isotactic, or mainly isotactic propylene homopolymer, 2) total content of comonomer is 0.05 to 20 wt%, propylene with ethylene and / or _C 4 -C ₈ alpha
A crystalline copolymer with an olefin, or a mixture of said copolymer and an isotactic or predominantly isotactic propylene homopolymer; 3) (A) a propylene homopolymer and / or 2) One kind of copolymer and (B) a heterophasic copolymer containing an elastomeric fraction containing a copolymer of ethylene and propylene and / or a C _{4 to} C ₈ α-olefin and optionally containing a small amount of a diene. A method characterized by being selected. 2. A method for producing a heat-weldable polyolefin fiber having a count of 0.5 to 3 dtex, wherein the short-spinning apparatus for staple fibers is used to operate at a fiber accumulation speed of 40 to 250 m / min. The true or equivalent exit hole diameter of the die to be spun is 0.5-2 mm, and the olefin polymer to be spun is: 1) isotactic or predominantly isotactic propylene homopolymer, 2) total comonomer Propylene and ethylene and / or C ₄ -C ₈ α having a content of 0.05 to 20% by weight.
A crystalline copolymer with an olefin, or a mixture of said copolymer and an isotactic or predominantly isotactic propylene homopolymer; 3) (A) a propylene homopolymer and / or 2) One kind of copolymer and (B) a heterophasic copolymer containing an elastomeric fraction containing a copolymer of ethylene and propylene and / or a C _{4 to} C ₈ α-olefin and optionally containing a small amount of a diene. A method characterized by being selected. 3. A true or equivalent outlet hole diameter of 0.5 to 3.
2. The method of claim 1, wherein the distance is 2 mm. 4. A hole flow rate of 0.005 to 0.18 g / min, a fiber accumulation speed of 50 to 100 m / min, and a draw ratio of 1.10 to 10.10 g / min.
4. The method according to any one of the preceding claims, wherein the method is 3.50. 5. The method according to claim 1, wherein the spinning temperature is 240 to 310 ° C. 6. The method according to claim 5, wherein the spinning temperature is from 270 to 300 ° C. 7. The stretching temperature used is less than 100 ° C.
The method according to claim 1. 8. The MFR of the olefin polymer to be spun is 1.
The method according to claim 1 or 2, wherein the weight is 5 to 35 g / 10 minutes. 9. A method for producing a heat-weldable polyolefin fiber, comprising operating using a spun-bonding apparatus.
The die used has a true or equivalent exit hole diameter of 0.5
mm or more, provided that the ratio of the outlet hole diameter to the number is 0.06 mm / dtex or more for fibers having a count of 4 dtex or more, and that the olefin polymer to be spun is: 1) isotactic Do, or mainly isotactic propylene homopolymer, 2) total content of comonomer is 0.05 to 20 wt%, propylene with ethylene and / or _C 4 -C ₈ alpha
A crystalline copolymer with an olefin, or a mixture of said copolymer and an isotactic or predominantly isotactic propylene homopolymer; 3) (A) a propylene homopolymer and / or 2) one copolymer, and (B) comprising ethylene and propylene and / or copolymers of C ₄ -C ₈ alpha-olefin, the heterophasic copolymer comprising an elastomeric fraction comprising a minor amount of a diene optionally A method characterized by being selected. 10. A process for producing a heat-weldable polyolefin fiber having a count of 0.5 to 3 diex, which is operated using a spun-bonding apparatus and has a true or equivalent exit hole diameter of a die used. 0.5 to 2 mm, wherein the olefin polymer to be spun is: 1) an isotactic or mainly isotactic propylene homopolymer, 2) a total comonomer content of 0.05 to 20% by weight, Propylene and ethylene and / or C ₄ -C ₈ α
A crystalline copolymer with an olefin, or a mixture of said copolymer and an isotactic or predominantly isotactic propylene homopolymer; 3) (A) a propylene homopolymer and / or 2) One kind of copolymer and (B) a heterophasic copolymer containing an elastomeric fraction containing a copolymer of ethylene and propylene and / or a C _{4 to} C ₈ α-olefin and optionally containing a small amount of a diene. A method characterized by being selected. 11. A true or equivalent exit hole diameter of 0.5.
The method of claim 9, wherein the distance is ２2 mm. 12. A hole flow rate of 0.1 to 2.0 g / min,
The method according to any one of claims 9 to 11, wherein the fiber accumulation speed is 400 to 4500 m / min. 13. An olefin polymer to be spun having an MFR of 5
The method according to claim 9 or 10, wherein the method is 25 g / 10 min. 14. An olefin polymer to be spun having an MFR of 8
14. The method according to claim 13, which is ~ 15 g / 10 min. 15. The method according to claim 9, wherein the spinning temperature is 230 to 300 ° C. 16. The method according to claim 15, wherein the spinning temperature is from 240 to 280 ° C. 17. The method according to claim 1, wherein the cooling space exceeds 2 mm.
The method according to 2, 9 or 10. 18. The olefin polymer to be spun comprises a stabilizer a) one or more phosphites and / or phosphonite 0.01 to 0.5% by weight, and b) one or more HALS 0.1% by weight. 005-0.5% by weight of at least one stabilizer, and optionally 1
11. The method according to claim 1, 2, 9 or 10, comprising at least one phenolic antioxidant in a concentration not exceeding 0.02% by weight.