FI107343B - A process for making hydrophobic polymer fibers and an apparatus for doing so - Google Patents

Abstract

The object of the present invention is a method for producing hydrophobic polymer fiber filaments, the method comprising the following steps forming a melt from a hydrophobic polymer, melt-spinning the polymer to form filaments, applying a spin finish to the filaments, and optionally crimping and cutting the filaments into staple fibers. According to the invention, the method includes a step of subjecting the filament to at least one surface treatment step, preferably using a corona discharge or plasma treatment to increase the surface free energy thereof. An object of the invention is also an apparatus or production line for carrying out the method. <IMAGE>

Description

107343

A process for making hydrophobic polymer fibers and an apparatus for doing so

Water spinning or "spunlacing" is a non-woven manufacturing process in which the fiber web is bonded by fine water jets under high pressure. In the most commonly used method 5, the carded web is placed on a moving conveyor belt which moves the web under a plurality of water jet lines. The water pressure in the showers gradually increases from the first row of showers to the last row. The mechanical energy released by the water jets into the web pins the fibers in the web. Knitting keeps the fibers in the nonwoven without the need for additional bonding, such as thermal bonding or chemical bonding.

More general information on hydroentanglement can be found, for example, in U.S. Patent Nos. 3,485,706 and 3,485,708 (Evans).

Different types of fiber compositions can be used to make water-needled nonwovens. Typical fibers used are cellulose-based fibers such as cotton, cellulose or viscose, and chemical fibers such as polyester (polyethylene terephthalate) or polypropylene. The commonly used fiber blend ratio is 30-70% by weight of viscose fibers and 70-30% by weight of polyester fibers.

However, the use of polypropylene fibers in hydroentanglement is limited by their hydrophobic nature. The drop of water forms a contact angle of about 105 ° on the polypropylene surface, while on the polyester surface it forms a contact angle of about 80 °. By definition, the surface is hydrophobic if the contact angle of water is greater than 90 ° and hydrophilic if said contact angle is less than 90 °. Due to this difference in the wetting properties of the fiber, the water needling of the polypropylene fiber-containing web is, for two reasons, more difficult than the water needling of the polyester fiber-containing web. First, as the amount of hydrophobic polypropylene fibers is increased in the web, the water-repellent property of the web increases. Due to the increase in water repellency, water jets do not penetrate the web completely. As a result of this effect, the hydroentangling energy absorbed by the web is reduced.

30

Second, the amount of avivator required to control the fiber surface properties is different for polypropylene and polyester fibers. Usually staple fiber spinning. The method comprises adding 0.5% by weight, on a polypropylene fiber surface, of avivating agents, calculated on the weight of 107343 fibers. For the polyester fiber surface, a leveling agent of 0.10-0.15%, based on the weight of the fibers, is sufficient. Usually, the avivating agent is a mixture of pints-k-active ingredients, including lubricants, antistatic agents, wetting agents and emulsifying agents. The purpose of the lubricants is to control the fiber · k li-5 tu cohesion and the fiber-to-fiber and fiber-to-metal friction. Antistatic agents reduce the accumulation of static charge during fiber treatment. Wetting agents restore the wettability properties of the fibers by reducing the contact angle of water on the fiber surface. Emulsifiers are used to create oil-in-water, conditioning agents, which can be diluted with water.

10

Surfactants, including avivating agents, pose problems in the water needling process. In hydroentanglement, avivating agents dissolve from fibers in the hydroentangling water. Dissolved avivating agents lower the surface tension of the needle water and stabilize the air bubbles in the vEj. Air stabilization causes foaming of water, which is undesirable in hydroentangling. Because the needle water must be purified by filtration and recycling, the amount of impurities dissolved in the fibers in the water must be kept as low as possible. The need for water for needling water in the water needling of a polypropylene fiber containing web is therefore high. This is because polypropylene fibers typically require about four times higher loading agent concentrations than polyester or viscose fibers.

Today, there are various techniques for modifying polymer surfaces. Techniques such as plasma, corona, or flame treatment increase the free surface energy of low-energy pie-polymer surfaces such as polyethylene or polypropylene. The increase in surface energy of the V.i-25 head can be observed as improved wetting properties and a decrease in the water contact angle. Plasma, corona and flame treatments are well known in the art of polymer technology. These techniques have been applied to modify fibrous materials, such as nonwovens, to improve the wettability or adhesion of the materials. JP 01192871 A describes a process in which a nonwoven containing hydrophobic fibers is subjected to a corona treatment to obtain hydrolytic properties on the fabric. WO 97/11834 discloses a corona treatment method that can be used, inter alia, to control the wettability properties of fused 107343 3 controlled nonwovens for hydrophobic nonwovens. Tsai and Wadsworth, Textile Res.J., vol.67 (1997), No. 5, p.359, report on plasma treatment to increase the free surface energy of polypropylene meltblown nonwovens.

The present invention relates to a process for the production of polymeric, in particular polyolefin fiber filaments with increased free surface energy, the process comprising forming a melt from a hydrophobic polymer, spinning the filament to form filaments, applying an avivating agent to the filaments and optionally curling and cutting the filaments. According to the invention, the surface treatment step, preferably the corona discharge, plasma or flame treatment step, is included in the method of increasing the free surface energy of the fibers. The invention also relates to an apparatus or production line for carrying out the invention. The objects, features and advantages of the invention will be fully apparent from the appended claims.

15

According to a preferred embodiment, free surface energy is raised by corona or plasma treatment. This results in two significant improvements over the state of the art. First of all, the wettability properties of the filaments and the fibers made from them are improved and the absorption of the needle energy of the web made from said fibers is enhanced by hydroentangling. Secondly, the amount of avivating agents · which give the fibers good ointment and antistatic properties can be reduced by 30-50% during spinning. Due to the lowering of the leveling agent additive, the web containing said fibers dissolves less in the circulating needle water.

25

Figure 1 is a schematic representation of the compact spinning process of polypropylene filaments. and staple fibers according to the invention.

Fig. 2 schematically shows an embodiment of a corona treatment unit used in accordance with the invention.

Figure 3 schematically shows a hydroentanglement production line.

107343 4

According to a preferred embodiment, the invention relates to a process for the production of polypropylene filaments and staple fibers therefrom for the manufacture of non-w / w boats to be woven. The method comprises treating a polypropylene filament tow with a corona discharge, plasma or flame treatment during a melt spinning process. Although polypropylene is a preferred hydrophobic fiber for the production of hydroentangled nonwovens, it is to be noted that the process is also applicable to the production of fibers from other polymers having low free surface energy (hydrogen contact angle greater than 90 °) such as polyethylene. Because corona treatment is performed in ambient air and is a continuous process, corona treatment 10 is a more preferred method of increasing the free surface energy of filaments during the melt spinning process than plasma or flame treatment techniques.

A typical corona discharge device, well known in the art, has two electrodes A high voltage AC, typically 9-30 kH, is applied to the working electrode; and 15 voltages of 10-15 kV. The high voltage causes the ionization of the air in the gap between the two electrodes. This results in an electron discharge known as a corona between the working electrode and another electrically grounded electrode. A grounded electrode is usually a stainless steel roll. Suitable materials for the working alloy are, for example, bare metals or ceramic materials. Between the insulator electrodes 20 0 there is a treated material and an air gap. When handling porous materials, such as filament tows, the material must be electrically isolated from the electrodes.

... This is done by covering the roll electrode with dielectric material or preferably using working electrodes coated with an insulating material such as a ceramic material. However, when using electrically insulated working electrodes, the corona treatment teκ 25 is reduced by about 50% compared to cases using bare metal grommets.

The applicability of conventional corona processing units having a roll electrode structure is limited to thin materials, since the air gap between the electrodes can usually be adjusted from 1 mm to 2.5 mm. When treating thick materials or materials having a 3-D structure, plasma or corona jets are preferred.

"Corona jets blast the surface of a material that has been generated by electric discharge with the concept of ionized air.

During the electrical discharge, the air gap between the electrodes forms ions, radicals, excited molecules, photons and ozone. These components contain enough energy to break the polymer chains on the surface of the polyolefin material to be treated to form polymer radicals. In the corona, oxygen, including oxygen radicals, and ozone react with polymeric radicals on the surface of the material to form peroxides. The peroxides further react on the polymer surface with oxygen-containing functional groups such as -C-OH, -C = O, -COOH, -COOC-10 and -C-O-C-. These polar oxygen-containing chemical groups increase the free surface energy of the polymeric material and improve the surface wettability properties.

Figure 1 shows a preferred embodiment of a line for producing polyolefin fibers having increased free surface energy. In the compact spinning line shown in Figure 1, the polymer granules are fed to an extruder (11), after which the molten polymer is pumped through a spinning nozzle (12) having a plurality of holes, usually 0.25 mm in diameter. The polymer filaments forming the filament tuft (13) are pulled from the spinning nozzle (12) by the first galethyst (17). After the spinning nozzle (12), the polymer filaments are quenched and the avivator is added to the filament towers (13) with a spin roll applicator (14). The surface treatment unit (15) increases the free surface energy of the polymer filaments in the tube (13) by corona discharge or plasma jet treatment. Preferably, the surface treatment unit (15) is capable of handling both sides of the tow (13). After surface treatment (15), the polymer filaments in the surface portion of the tow (13) have an average water contact angle value of less than 95 ° and preferably a contact angle value of less than 90 °. Since the surface treatment (15) generates some electrical charge in the polymer filaments, the film-to-filament cohesion in the tow (13) is reduced. For this reason, in order to eliminate the electric charge from the towers (13), it is preferable to use a second cavity-smear roll applicator (16) after the surface treatment (15). Since the added cavity agent in the filament tows (13) tends to reduce the efficiency of the surface treatment (15), the level of curing agent in the first lubricating roll applicator (14) is preferably less than 107343 6 0.10% by weight of the tow. The surface treatment (15) is preferably carried out after the spinning nozzle (12), in the vicinity thereof, whereby the drip roll applicator (14) can be omitted. According to a preferred embodiment not shown in the figure, the surface treatment / step may be performed before the squeegee roll applicator (14), the embodiment further comprising a second surface treatment (20) and a subsequent conditioning agent addition step (21) after the drawing furnace (18). . This surface treatment site near the spinning nozzle is advantageous because the filament screw (13) is wide and thin at this point. Here too, the filament screw (13) is unfinished and the loss of power due to the surfactant is avoided.

10

The filament screw (13) is pulled in the drawing furnace (18) by a second galette set (19). When brought v.

(13) is surface-treated before the drawing furnace (18), the draw ratio λ should preferably be less than 1.50 and most preferably less than 1.20, since the drawing extends and increases the untreated area of the fiber tow (13). If the tensile ratio k 15 is greater than 1.50, the second surface treatment unit (20) can be installed after the Galet sion (19), the most extended! to repaint the area.

Once the filament screw (13) is surface-treated and retracted, it is re-treated with avivating agents. in a roller applicator (21) and curl in a curler 2 0 (22). The curled filament screw is dried in a drying oven (23) and finally cut into staple fibers in a cutter (24). It should be noted that other fiber spinning techniques, such as long spinning, can also be used to prepare the polyolefin fibers of the invention.

Figure 2 shows schematically a typical interest processing unit for handling a filament tow (13). The components are as follows: (25) corona discharge high voltage transformer, (26) discharge electrodes, (27) air gaps (28) earthed metal rolls.

Figure 3 schematically illustrates a typical production line for the production of hydroentangled nonwovens having the following components: (31) fiber baiter, (32) carding, (33) first hydroentangling station, (34) second hydroentangling station (35), dryer and (3 3) 107343 7 nonwoven winding machine.

The polyolefin staple fibers produced according to the present invention are characterized by an increase in free surface energy when compared to fibers made without the described surface treatment. Untreated polyolefin fibers, especially polypropylene and polyethylene fibers, have a water contact angle value of about 95 ° to 105 ° or a critical surface tension of less than 33 mN / m. The surface treated fibers have an average contact angle less than 95 °, or a critical surface tension greater than 33 mN / m, and more preferably a contact angle less than 10 °, or a critical surface tension greater than 35 mN / m. The water contact angles for the individual fibers can range from 60 ° to about 105 °, or critical surface tension values from 49 mN / m to about 31 mN / m. This variation is due to variations in the exposure of individual filaments to surface treatment. It is clear that the filaments on both sides of the touvium absorb most of the processing energy while the filaments in the center of the touvium receive less processing.

It has now been found that corona-treated polyolefin, preferably polypropylene filaments and fibers can be provided with sufficient antistatic and hydrophilic properties by using 30-50% less avivating agents than is currently the case in the art. It is believed that as the free surface energy of the polyolefin fibers rises, the opacifying agents are more evenly distributed on the fiber surface. The critical surface tension of newly spun polypropylene filaments used to make polypropylene staple fibers for water jetting has been determined to vary from 30.3 mN / m to 31.0 mN / m. On the other hand, the surface tension of pure avivating oils is usually in the same range, while the surface tension of the aqueous dispersion of avivating agents used in the manufacture of polypropylene staple fibers ranges from 30 mN / m to 40 mN / m. It is well known to one of ordinary skill in the art that a liquid having a surface tension lower than the critical surface tension of a solid surface will completely wet the solid surface. Thus. that is, if the surface tension of the conditioning agent is close to but not below the critical surface tension of the hydrophobic fiber, the propagation of the conditioning agent can be improved by increasing the free surface energy of the fiber.

107343 8

However, the wetting properties of surfactant solutions cannot be evaluated by comparing the surface tension values of the wetting liquid with the critical surface tension of the fiber, due to adsorbing effects of surfactants and high water polarity. The diluents studied formed an emulsion with a surface tension ranging from 32 mN / m to 38 mN / m. Advancing contact angle has been found to vary between 49 ° and 57 ° and receding contact angle between 20 ° and 27 ° depending on the concentration of avivating agent in water. This indicates that the fibers are incompletely wetted by the avivator emulsions. Thus, increasing the free surface energy of the fibers 10 by corona treatment improves the wetting property of the avivating agents and penetration into the fiber tows during the fiber spinning process. In particular, the wettability of the surface of the tow is improved because the fibers on the surface absorb much of the processing energy.

It is believed that the antistatic properties of the fibers are improved not only by the better diffusion of the avionics but also by the increase in the free surface energy of the fibers during processing. As the hydrophilicity of the fibers increases, more water is adsorbed to the bare fiber surface from moist air. Water forms a conductive layer on the surface, which removes the static charge. It is believed that both improved dispersion of avivating agent 20 and increased hydrophilicity of the fiber surface improve the antistatic self-consistency of the fibers.

··

The reduction in the content of avivating agent is particularly advantageous in the manufacture of water-woven nonwoven fabrics using polyolefin staple fibers, preferably polypropylene staple fibers. Addition of avivating agent in the range of 0.05-0.3, usually 0.05-0.2, such as 0.10-0.15% by weight of the fibers, was found to give satisfactory pirti properties, such as an a polypropylene peenikuiduille. This means that a significant reduction in the impurities soluble in the fibers to the needle water during the water needling of the polyolefin fiber containing webs can be achieved. As a result, the needle water will foam less and the water recycling rate can be increased.

107343 9

Corona treatment results in improved adhesion of wetting agents to the treated fibers. This results in a better resistance to hydrophilicity of the fibers treated with avivating agents as the desorption rate of wetting agents from the surface of the fibers to the surrounding fluid decreases. The improved resistance to fiber hydrophilicity 5 due to corona treatment has the advantage that the fibers of the invention are used, for example, in the manufacture of thermally bonded nonwoven materials for use as, for example, protective materials in absorbent hygiene products.

10 Examples

The following examples illustrate, but are not limited to, the basic features of the new invention. The following are the test methods used to characterize fibers and nonwoven fabrics in the Examples:

Water Contact Angles The wettability of treated and untreated polypropylene fibers and filaments was determined by the Wilhelmy plate dynamic contact angle method. Fiber advancing and receding contact angles in water were measured with a Cahn DCA-322 dy-20 face contact angle analyzer using an immersion rate of 20 µm / s.

The immersion depth of the fiber was in the range of 1-2 mm. The fiber circumference required in the method as a parameter was determined microscopically.

Determination of Avivator Addition Level The fiber avivator addition level was determined by the following procedure: 3 g of fiber and extracted with 150 ml of ethyl ether. After extraction, the ethyl ether was evaporated and the residue was dissolved in 10 ml of carbon tetrachloride. The concentration of avivating agent in the solution was analyzed on a Perkin Elmer "Spectrum 1000" FT-IR spectrometer by determining the height of the IR absorption peak at 1738.7 cm @ -1 (corresponding to C = C30 bond).

1073415 10

Antistatic properties of fibers

To characterize the antistatic properties of the staple fibers, the electrical resistance of the fibers was measured with an Eltex Tera-Ohm 6206 resistance meter using a ring electrode in accordance with DIN 54345 Tl. The fibers were carded to web, and for 1 g of web samples, the resistance was measured after 16 hours under standard conditions of 60% relative humidity and 25 ° C. The electrical resistance represents the ability of the fibers to remove static charge. Thus, the higher the resistance of the fiber, the worse the antistatic properties. Normally, staple fibers require a resistance less than 10 ^ Ω for nonwoven production. You evaluate the antistatic properties in 10 according to the following scale based on the measured values of the electrical resistance: R / Ω: R> 1013 = 0, 1011 <R <1012 = bad, 1010 <R <1011 = triple, R <10 ^ = good.

The antistatic properties were further characterized by measuring the static charge of the carding Aila and 15 webs with an Eltex EM-01 Fieldmeter. 25 g of staple fibers were carded at 60% relative humidity at 25 ° C and the electric field was measured by placing a field sensor at a distance of 6.0 cm above the web.

Water Absorption Time of Fibers The fibers were carded to web and the settling time of the web placed on top of the water tank was determined by EDANA Recommended Test Method ERT 10.2-96.1. According to "Liquid Absorbency T -... me".

Example 1 A polypropylene fiber screw containing 30500 filaments was extruded in the compact spinning line shown in Figure 1. The titer of non-avivating fibers was 5.0 dtex. The fiber tube was corona treated with a Sherman treaters PBS350 electrode unit (Figure 1 (15)) coupled to a Sherman treaters GX20 generator. The processing energy ranged from 0.3 to 1.6 J / cm 2. As a reference sample, 30 identical fiber tows were prepared without corona treatment.

. The effect of corona treatment was investigated by measuring the water contact angle 10 of 107343 11 on the surface of the filament taken from randomly treated and untreated fibrous filaments. The average contact angle values are shown in Table 1. Table 1 shows that the corona treatment of the polypropylene fiber fiber increases the free surface energy of the touvium filaments. This can be seen in the reduction of the contact angle values of the filament water 5 as a function of corona processing energy.

Table 1. Water Contact Angles of Unfinished Polypropylene Filaments Sample Corona Energy Contact Angle Contact Angle J / cm2 Advancing0 Receding0 10 1.0 0 101 96 1.1 0.3 89 74 1.2 0.8 93 83 1.3 1.6 85 69 15

Example 2 In this example, 3.5 dtex polypropylene staple fibers were made with the compact spinning line shown in Figure 1. Referring to Figure 1, the corona treatment (15) was performed after the first-to-first opening (14) as described in Example 1. A second avivation 20 (21) was performed before the curling (22). During production, the corona treatment energy was 0.6 Λ J / cm. Four batches of corona-treated staple fibers were made having an avivating agent content of between 0.11% and 0.20% by weight of the fibers. Comparative samples were made of untreated fibers with the same avivating agent additions.

»· · 25 The most fibrous contact angle after corona treatment was measured as described in Example 1 as an average of 50 individual filaments. The corona treated filaments showed an advancing contact angle of 93 ° and a receding contact angle of 79 °. The contact angle values of the untreated filaments were 101 ° and 91 °, respectively.

. The antistatic properties of the fibers were characterized by measuring the resistance of the fibers.

12 1073 ^ -3

The hydrophilicity of the fibers was evaluated by the water absorption time test method. Table 2 and Table 2 show the measured properties of the fibers with different additive agents.

Table 2.

5 Sample Avivating agent - Corona - Resistant Antistatic - Waterfilming energy ΙΟ9 Ω% self-sorption weight% J / cm2 females.

s 2.1 0.11 0> 1000 0> 600 2.2 0.13 0 100 poor> 600 2.3 0.18 0 10 moderate 3.4 0.20 0 6.4 good 2.9 10 2.5 0.11 0.8 100 poor> 600 2.6 0.13 0.8 8.3 good 3.3 2.7 0.18 0.8 2.2 good 2.3 2.8 0.20 0.8 1.5 good 2.3 ·· <15

As can be seen in Table 2, the untreated fibers are hydrophobic and have poor antistatic properties when the amount of avivating agent is less than 0.18% by weight. On the other hand, corona-treated fibers are hydrophilic and have good anti-static properties as early as 0.13 wt% avivant addition. The results in Table 20 clearly show that, when the fiber tow is corona treated, the fibers of La with sufficient antistatic and hydrophilic properties can be prepared by using n sharply reduced avivant additive concentrations.

107343 13

Example 3 In this example, 2.2 dtex polypropylene staple fibers were made with the compact spinning line shown in Figure 1 as described in Example 2. The corona treatment energy δ was 0.6 J / cm 2 during manufacture. Two batches of corona treated staple fibers with an avivating agent additive content of between 0.09% and 0.12% by weight of the fibers were prepared. Untreated fibers with the same avivating agent additions were prepared as control samples.

After corona treatment, the contact angle of the most fibrous fiber was measured as described in Example 1 as an average of 40 individual filaments. For corona treated filaments an advancing contact angle value of 92 ° and a receding contact angle value of 83 ° were observed. The contact angle values of the untreated filaments were 97 ° and 91 °, respectively. The antistatic and hydrophilic properties of the fibers were characterized as described in Example 2. In addition, the static charge accumulated during carding was measured.

The results are shown in Table 3.

14 10734ο

Table 3.

Sample Avivoin- Corona- Resistance Anti- Formation- Water Absorbent Energy ΙΟ9 Ω Static Nut Static Sorption Increase J / cm ^ Specific charge k Time Weight% Mouths -V / ms - r '11 - ~ -' - - - - 3.1 0.09 0> 1000 0> 50> 600 5 3.2 0.12 0 50 spot- 16> 600 la 3.3 3.3 0.09 0.6 260 poor 20> 600 3.4 0.12 0.6 8.1 good 9> 600 10 The results shown in Table 3 show that even when the amount of avivator is low enough not to make the fibers hydrophilic (settling time values> 600 s), the co-treated fibers have significantly better antistatic properties - about 50% less static charge as with untreated fibers. It can be concluded that polypropylene fibers having good antistatic properties can be produced by corona treatment during melt spinning when the amount of avivating agent is as low as 0.12% by weight.

Claims (15)

A process for producing hydrophobic polymeric fiber filaments which exhibits an elevated free surface energy, the process comprising the following step 5. a melt of hydrophobic polymer is formed, - the polymer is melt spun to form filaments, a step in which at least one wool treatment step is performed on the filaments to increase their free surface energy. 10 2. A method according to claim 1, characterized in that the surface treatment step comprises a corona discharge, plasma or flame treatment. 3. A process according to claim 1 or 2, characterized in that the polymer is a polyolefin, preferably polypropylene. 4. A method according to claim 1, 2 or 3, characterized in that the stripping agent is applied to the filaments after the surface treatment step. 20 Process according to any of the preceding claims, characterized in that the surface treatment step is carried out after filament formation after the melt spinning, in the vicinity thereof. Method according to any of the preceding claims, characterized in that it comprises a step of drawing the filament. 7. A method according to claim 6, characterized in that when the tensile ratio used in the tensile step is above 1.50, the filaments are subjected to a surface treatment step after the tensile step. 1072 '[δ Method according to any of the preceding claims, characterized in that: in that the stripping agent addition is 0.05-0.3, preferably 0.05-0.2% by weight based on filament weight. 5 9. A method according to any one of the preceding claims 2-8, characterized in data v, that the corona discharge energy used is 0.3-1.6 J / cm 2. 10. A method according to any of the previous claims, characterized in that it comprises the following step 10. crimping of the filaments and cutting into staple fibers, - carding of the staple fibers and producing nonwoven thereof, <> 1 - water kneading of nonwoven. A production line for producing hydrophobic polymer fiber filaments, preferably polyolefin, such as polypropylene fiber filaments, which production line comprises - devices (11,12) for producing polymer filaments from a polymer melt, - devices (14, 16, 21) for applying strippers to 20 the filaments and optionally reaming devices (23) and cutting (24) of the filaments into staple fibers, characterized in that the production line comprises - devices (15, 20) for surface treatment of the filaments to raise it? free surface energy. 25 Production line according to claim 11, characterized in that the surface treatment devices comprise a corona discharge or plasma treatment unit. 107343 13. Production line according to claim 11 or 12, characterized in that it comprises devices for drawing the filaments. Production line according to claim 13, characterized in that the surface treatment devices are arranged after the tensioning devices in the production direction of the filaments. Use of a filament or fiber made with a method according to any one of claims 1-10 or in a production line according to any one of claims 11-14 for the production of nonwoven in a water grinding process. 15