PT2185757E - Method for producing a textile fabric consisting of at least partially split yarns, fibers or filaments - Google Patents

Abstract

The invention relates to a simple and economical method for producing textile fabric consisting of at least partially split yarns, fibres or filaments, in which, in particular, time consuming, energy and/or cost intensive processes are avoided. As a result, a dividable, initial textile fabric is divided or split at least partially into elementary filaments by treatment, in particular bombardment with dry ice, frozen water or an air-particle mixture at a temperature of at least 20 °C to 30 °C below the glass transition temperature (Tg) of the polymers used as yarns, fibres or filaments.

Description

1

DESCRIPTION OF THE DRAWINGS FOR THE PRODUCTION OF A WOVEN, FIBER OR FILAMENT AT LEAST PARTIALLY DIVIDED TEXTILE AND DEVICE FOR THE RESPECTIVE PRODUCTION " The present invention relates to a process for producing a partially divided yarn, fiber or filament textile fabric and a device for producing it.

From EP 0 814 188 B1 it is known to produce a nonwoven fragile fabric of endless bicomponent filaments from the incompatible initial fabrics polyethylene terephthalate and polyamide 6. In this case the nonwoven fabric is subjected to the action of jets of pressure for the separation of the elementary filament connecting elements as well as for the respective wrapping and the connection thereof.

A process for the production of polymeric products, which are charged with fine particles, is known from EP 0291026.

A process for treating the textile surface through a dry ice loading is known from WO 01/36733.

A process for the production of at least partially divided yarn, fiber or filament textile fabric is known from EP 1428919. The present invention aims to disclose a process which simplifies and makes economically advantageous the tissue production process woven fabrics of yarn, fibers or filaments.

For the production process of divided yarn, fiber or filament textile fabric only a particularly low energy or reduced mechanical force should be required, for example in contrast to a high pressure water jet treatment, in particular by means of pressures from approximately 120 bar to 500 bar.

Furthermore the process is intended to suppress additional procedures particularly requiring high time, energy and / or intensive costs, such as drying of the textile fabric required in the case of a water jet treatment.

Furthermore the process is intended to enable the at least partial division of yarns, fibers or conjugate filaments both composed of polymers compatible with one another and composed of polymers incompatible with one another.

The proposed objects are achieved by the features of claims 1 to 7.

With regard to the process according to the present invention an initial textile fabric cleavable by treatment, particularly by bombardment, with dry ice, with frozen water or with an air-particle mixture, at a temperature of at least 20 ° C at 30 ° C below the glass transition temperature (Tg) of the polymers used as yarns, as fibers or as filaments is at least partially fragmented or divided into elementary filaments. The glass transition temperature (T g) or the softening temperature of an amorphous polymer used is the temperature at which the polymer exhibits the greatest change in the deformability. The so-called glass transition separates the region of elastic energy located below (glassy region) of the region of elastic entropy located above (elastic region). The transition to the creep region of the amorphous polymer is flowing. The partially crystalline polymers have both a glass transition temperature, below which the amorphous phase " freezes " (implying embrittlement), as a melting temperature, by which the crystalline phase dissolves. The melting temperature clearly separates the elastic entropy region from the creep region.

As solid particles of the air-particle mixture, particularly inorganic particles are considered, for example, sand (for example quartz sand) or polymeric granules.

Preferably the dry ice, the frozen water or the air-particle mixture are used in the form of pellets. For dry ice or frozen water, use in the form of snow is also considered.

Dry ice pellets are preferably cylindrical particles having a diameter of approx. 3 mm and a length of between 5 mm and 30 mm. Dry ice snow should be understood to mean particles of finer grain and therefore less hard, having a diameter of approx. 0.1 mm and a length of 1 mm or less.

In the case of dry ice, this is frozen carbon dioxide at a temperature of approximately -78.5 ° C, which is brought to the gaseous state without leaving residues (sublimation) by striking the fragile initial textile.

Therefore the use of dry ice has the advantage that no further separation or filtration of the fragmented elementary filaments takes place, for example, in the case of the use of an air-sand mixture.

In addition, in the case of the use of dry ice under normal pressure, no liquid is formed, for example in the case of water ice, whereby the designation of dry ice has arisen.

Considering that in the process according to the invention with dry ice, frozen water or the air-particle mixture no liquid, particularly liquid water, is used for the fragmentation, the drying process of the yarn textile fabric is suppressed, at least partially divided fibers or filaments which requires high consumption of time, energy and / or intensive costs normally required, for example in the case of a water jet treatment. 5

By dry ice bombardment the surface temperature treated by the selected procedure parameters drops by approx. 60 ° C.

In the case of the use of an air-particle or frozen water mixture the treatment temperature is selected such that the temperature of the treated surface is at least 20 ° C to 30 ° C below the glass transition temperature (Tg) of polymers used as yarns, as fibers or as filaments.

Considering that the treatment temperature is at least 20 ° C to 30 ° C below the glass transition temperature (Tg) of the polymers used as yarns, as fibers or as filaments, a certain embrittlement of the polymers is achieved, and therefore at least supported or sustained the fragmentation of the textile fabric into elementary filaments, without damaging the elementary filaments.

Damage of the elementary filaments is also avoided by the reduced hardness of the dry ice, the air-sand mixture or the frozen water. The use in the form of snow in the place of pellets due to their smaller particle size or to their reduced hardness (" higher softness) is particularly preferred for particularly non-damaging fragmentation or partitioning of the elementary filaments.

Through the sublimation effect of the dry ice in the treatment of the fragile initial textile fabric the volume of carbon dioxide from the solid aggregate to the gaseous aggregate state 6 suddenly expands to approximately 600 to 800 times the respective initial volume. In this case the dry ice deposits between the elementary filaments, whereby the fragmentation of the textile fabric into elementary filaments is also at least partly supported or sustained.

As an arrangement of the elementary filaments, seen from the cross-section of the yarns, fibers or filaments, a core-sheat structure or an orange-like structure or a tranches-like structure is considered. Particularly preferably as a fragile initial textile fabric is used a fabric, wherein the elementary filaments are in a pie structure, preferably 2 to 64 segments, particularly to influence the diameter of the filaments.

Preferred embodiments are the subject of the dependent claims.

Advantageously as the fragile initial textile fabric is a non-woven fabric. As non-woven fabric, preferably non-woven fabrics of discontinuous fiber or spunbond non-woven fabrics are used with endless fibers or with composite fibers obtained either by a melt-spinning process or by a solvent-wrapping process .

Preferably, nonwoven fabrics obtained by melt-winding are used which, compared to non-woven fabrics obtained by winding using solvents, have the advantage that no solvent has to be removed and that its use is more economical.

As the fragile initial textile fabric a pre-hardened non-woven fabric is preferably used, which is pre-hardened thermally, mechanically and / or chemically, particularly preferably thermally pre-hardened.

The yarns, fibers, or filaments of the textile fabric preferably have at least two elementary filaments, selected from the polymer pairs or mixtures of polyolefins, polyesters, polyamides and / or polyurethanes combined arbitrarily.

Preferred polyolefins are, for example, polyethylene or polypropylene, as preferred polyesters for example polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, recycled polyesters, polylactate or copolyester, as preferred polyamides for example polyamide 6, polyamide 12, polyamide 66 or copolyamides.

To achieve good efficiency the treatment, particularly the bombardment, of the surface of the fragile initial textile fabric with the dry ice, the frozen water or the air-particle mixture is preferably carried out under an impact angle of 0.1 ° to 180 ° , preferably from 45 ° to 135 ° and particularly preferably from 90 °. The kinetic energy of the particles of the dry ice, the frozen water or the air-particle mixture in this case is advantageously equal to or greater than 0.4 joule. In this case the mass and velocity of the particles is selected so that no optical damage of the textile fabric or formation of holes in the textile fabric is generated. The flow rate of dry ice, frozen water or air-particle mixture is advantageously 30 kg / h at 70 kg / h, preferably 30 kg / h at 50 kg / hr.

The particles of the dry ice, the frozen water or the air-particle mixture preferably smear on the surface of the fragile initial textile fabric with an average size of 10 andm to 30 mm, particularly preferably 0.1 mm to 10 mm. The shelling of the surface of the fragile initial textile fabric with the dry ice, the frozen water or the air-particle mixture is preferably carried out at a speed of 100 m / s at 500 m / s by a feed rate of the outlet valve of 2 , 5 m / min at 12.5 m / min, particularly preferably 2.5 m / min at 5 m / min. Fragmentation in elementary filaments is advantageously carried out by pressures of 0.5 bar to 16 bar, preferably of 0.5 bar to 6 bar, particularly preferably of 0.5 bar to 2 bar.

Furthermore, a particularly suitable device is provided for the process according to the present invention, which enables said process in a simple way. 9

For said purpose the device for the fragmentation of a textile fabric of at least partially divided yarns, fibers or filaments consisting of at least two elementary filaments, particularly according to the process according to claims 1 to 7, presents at least one outlet valve directed against the fragile initial textile fabric for the bombardment of the at least one fragmentable surface of the fragile initial textile fabric with dry ice, with frozen water or with an air-particle mixture.

Advantageously in at least one outlet valve are inserts for the fragmentation of the dry ice, the frozen water or the air-particle mixture.

Carrying out the invention

Thereafter the object of the present invention is more fully explained on the basis of examples and figures.

1 shows a REM image of a 100 fold enlarged cutout of the surface of a spunbond nonwoven fabric divided with dry ice pellets at 2 bar and thermally pre-hardened according to the present invention of PET / PA6 foot fibers segmented with a weight ratio of 70:30;

In FIG. 2 a REM image is shown of a 100 fold enlarged cutout of the surface of a spunbond non-woven fabric divided with dry ice snow at 2 bar (non-thermally pre-hardened) according to the present invention of PET foot fibers / PA6 with a weight ratio of 70:30 and 10

3 shows a REM image of a 100 fold enlarged cutout of the surface of a spunbond non-woven fabric divided with dry ice snow at 1 bar (untempered pre-hardened) according to the present invention of PET foot fibers / PA6 segmented with a weight ratio of 70:30.

Scanning electron microscope images (REM images) were produced with a JEOL JSM-6480LV low pressure scanning electron microscope at an acceleration voltage of 20 kV.

Example 1:

According to example 1 a spunbond non-woven fabric, particularly a non-woven fabric obtained by melt-wound, from bicomponent filaments with a 16-segment pie structure, alternately comprised of polyethylene terephthalate / polyamide 6 ( PET / PA6) in a weight ratio of 70:30, is bombarded with dry ice pellets.

In addition the spunbond non-woven fabric is minimally needled and therefore minimally mechanically hardened, so that the spunbond non-woven fabric can be transported. In addition, the spunbond non-woven fabric is thermally pre-hardened, the thermal pre-hardening being carried out in a heated disk press for a period of 30 seconds at a temperature of 150 ° C and at a pressure of 300 bar .

For splitting the filaments into the spunbond nonwoven fabric the spunbond nonwoven fabric is placed at a 90 ° angle 11 below the outlet valve of the dry ice pellets. In the case of the shape of the valve, this is a wide-tip valve with a rectangular outlet surface measuring 50 mm x 4 mm. Said valve is used to distribute energy on as large a surface as possible, in principle a round valve can also be used in principle.

Subsequently the spunbond nonwoven fabric is vertically bombarded with dry ice pellets. Polyethylene terephthalate (crystalline) in accordance with ISO 75 HDT / A (1.8 MPa) has a glass transition temperature (Tg) of approx. 80 ° C and a melting temperature of approx. 255 ° C in accordance with ISO 11359) and polyamide 6 in accordance with ISO 75 HDT / A (1.8 MPa) has a glass transition temperature (Tg) of approx. 65 ° C and a melting temperature of approx. 220 ° C in accordance with ISO 11359).

Dry ice pellets have a diameter of approximately 3 mm and a length of 1 cm. In the case of a dry ice density of 1.56 g / cm 3 a pellet weighs approx. 0.11 g (mass m). Pelletizing with dry ice pellets is carried out at a throughput of 50 kg / h at a speed (v) of 300 m / s dry ice pellets.

Therefore the kinetic energy (Ekin = 0.5 m v 2 = 0.5 x 0.11 = 10-3 kg x (300 m / s) 2 = 4.95 kg m 2 / s 2) of the dry ice pellets is 4.95 joule. The distance between the outlet valve and the surface of the fragile spunbond non-woven fabric is comprised between 10 mm and 100 mm, preferably between 25 mm and 75 mm. The pressure of the dry ice pellets during the bombardment of the spunbond non-woven fabric is 2 bar. The feed rate of the outlet valve is 5 m / min. Figure 1 shows a scanning electron microscope image of the spunbond non-woven fabric of Example 1.

Example 2:

In example 2 unlike example 1 in place of the dry ice pellets dry ice snow having a particle size of approx. 0.1 mm x 0.5 mm. Dry ice snow weighs 0.0105 g (mass m). The dry ice snow bombardment is performed at a speed (v) of 300 m / s.

Therefore the kinetic energy (Ekin = 0.5 m v 2 = 0.5 x 0.0105 = 10-3 kg x (300 m / s) 2 = 0.4725 kg m 2 / s 2) of the dry ice snow is 0.4725 joule.

In addition, spunbond non-woven fabric of bicomponent filaments with a 16-segment pie structure consisting of polyethylene terephthalate / polyamide 6 in a weight ratio of 70:30 is used. Unlike the procedure in Example 1 the non-woven fabric is not thermally pre-hardened. Incidentally, the process is carried out in a manner analogous to the conditions of Example 1, only dry ice pellets being used instead of the dry ice pellets. Figure 2 shows a scanning electron microscope image of the spunbond nonwoven fabric of Example 2.

Due to the absence of thermal pre-hardening the filaments are more flexible than according to example 1.

Example 3:

In the process according to example 3, a non-woven spunbond nonwoven fabric of bicomponent filaments having a 16 segment structure made of polyethylene terephthalate / polyamide 6 in a weight ratio of 70:30 is also used. The process is performed in a manner analogous to the conditions of Example 2, with dry ice snow instead of dry ice pellets. Unlike Example 2 the dry ice snow pressure in Example 3 during the bombardment of the spunbond non-woven fabric is only 1 bar instead of 2 bar. Figure 3 shows a scanning electron microscope image of the spunbond non-woven fabric of example 3. Said process according to example 3 demonstrates that fragmentation into elementary filaments continues to be quite possible even under a pressure of 1 bar .

Lisbon, May 22, 2012

Claims (3)

A process for the production of textile fabrics consisting of at least partially divided yarns, fibers or filaments, which are formed by at least two elementary filaments, characterized by an initial textile fabric by treatment, in particular by bombardment, with dry ice, frozen water or an air-particle mixture, at a temperature of at least 20 ° C to 30 ° C below the glass transition temperature (Tg) of the polymers used as yarns, as fibers or as least partially fragmented or divided into elementary filaments. The process according to claim 1, wherein as the fragile initial textile fabric there is used a nonwoven fabric, particularly a spunbond nonwoven fabric. The process according to claim 1 or 2, wherein a prehardened nonwoven fabric is used as the fragile starting textile fabric. The process according to any one of the preceding claims, wherein the yarns, fibers or filaments have at least two elementary filaments, selected from the polymer pairs or the polymer blends of polyolefins, polyesters, polyamides and / or polyurethanes arbitrarily combined. The process according to any one of the preceding claims, wherein the treatment, particularly bombardment, on the surface of the fragile initial textile fabric with dry ice, with frozen water or with an air-particle mixture is carried out at an angle (a) from 0.1 ° to 180 °, preferably from 45 ° to 135 °, particularly preferably from 90 °. The process according to any one of the preceding claims, wherein the kinetic energy of the dry ice, frozen water or air-particle mixture particles is equal to or greater than 0.4 joule. The process according to any one of the preceding claims, wherein fragmentation into elementary filaments is carried out at pressures from 0.5 bar to 16 bar, preferably from 0.5 bar to 6 bar, particularly preferably from 0.5 bar at 2 bar. Lisbon, May 22, 2012