JP2010538170A - Method for producing a fabric having yarns, fibers or filaments at least partially defibrated and production device therefor - Google Patents

Abstract

  The present invention is a simple and economical method for producing a fabric composed of at least partially defibrated yarns, fibers or filaments, in particular a time consuming, energy and / or cost intensive process. The present invention relates to a fabric manufacturing method that can be avoided. As a result, the first fabric that can be divided is treated with dry ice, frozen water, or air-particle mixture at a temperature that is at least 20-30 ° C. lower than the glass transition temperature (Tg) of the polymer used as yarn, fiber, or filament. In particular, when subjected to an impact, it is split or defibrated at least partially into basic filaments.

Description

  The present invention relates to a method of forming a fabric having yarns, fibers or filaments that are at least partially split, and an apparatus for forming the fabric.

  The following patent document describes the formation of a fibrous nonwoven web that is easily defibrated from continuous bicomponent filaments composed of polyethylene terephthalate and nylon 6 which are incompatible starting materials. A method is disclosed. In that method, the fibrous nonwoven web is exposed to the action of a liquid pressure jet in order to separate the composite elements into elementary filaments and entangle them together.

European Patent No. 0814188B1

  The object of the present invention is to provide a method in which the operation of forming a fabric from defibable yarns, fibers or filaments is particularly simple and economical.

  This operation of forming a fabric comprising yarns, fibers or filaments that can be at least partially defibrated requires very little energy or mechanical force compared to, for example, a high-pressure water jet treatment (especially a pressure of about 120-500 bar). do not need.

  This method further does not require extra time, energy and / or expensive work, such as the drying operation of the fabric required in the case of a water jet process, for example.

  In this method, the conjugate yarns, fibers or filaments are further at least partially defibrated, whether they are composed of mutually compatible polymers or whether they are composed of mutually incompatible polymers. It becomes possible to do.

  Another object of the present invention is to provide a device which is particularly suitable for this method and therefore can be easily implemented.

  Applicants have found that the above objects are achieved by the features of claims 1 and 10.

  The method of the present invention comprises a defibrating starting fabric at a temperature that is at least 20 ° C. to 30 ° C. below the glass transition temperature (Tg) of a polymer used as a fiber or filament by dry ice, frozen water or air-particle mixture. Treating, more specifically, defibrating at least partially to the basic filament by applying an impact.

  The glass transition temperature (Tg) or softening temperature of the amorphous polymer used is the temperature at which the polymer exhibits the greatest change in its deformability. The so-called glass transition separates the low quality and brittle energy elastic region (glass region) from the dominant soft entropy elastic region (rubber elastic region). The transition of the amorphous polymer to the fluid region is fluid. Partially crystalline polymers have both a glass transition temperature below which the amorphous phase “freezes” (with embrittlement) and a melting temperature at which no crystalline phase exists. The melting temperature is a clear boundary between the entropy elastic region and the fluid region.

  Solid particles useful as an air-particle mixture include inorganic particles such as sand (eg, silica sand) or polymer granules.

  Dry ice, frozen water or air-particle mixtures are preferably used in the form of pellets. Snow is also possible with dry ice or frozen water.

  The dry ice pellets used are preferably cylindrical particles having a diameter of about 3 mm and a length of between 5 and 30 mm. In contrast, dry ice snow refers to finer granular particles, and therefore less coarse particles, eg, about 0.1 mm in diameter and 1 mm or less in length.

  Dry ice contains frozen carbon dioxide at a temperature of about −78.5 ° C. when it reaches the defibrating starting fabric and transitions (sublimates) to a gaseous state without leaving a residue.

  Therefore, the use of dry ice has the advantage that, for example, when using an air-sand mixture, there is no need to separate and filter after the defibrated basic filament.

  Further, when dry ice is used under atmospheric pressure, no liquid is formed as in the case of water ice, for example, and is therefore referred to as “dry ice”.

  In the method of the present invention, when using dry ice, frozen water or an air-particle mixture, a liquid, more specifically, liquid water is not used for the purpose of defibration. In contrast, a fabric comprising at least partially defibrated yarns, fibers or filaments generally eliminates the need for a particularly required time, energy and / or costly drying operation.

  The impact of dry ice under selected process parameters will reduce the temperature of the treated surface by about 60 ° C.

  When using an air-particle mixture or frozen water, the treatment temperature is selected so that the temperature of the treated surface is at least 20-30 ° C. lower than the glass transition temperature (Tg) of the polymer used as the yarn, fiber or filament.

  Since the processing temperature is at least 20-30 ° C. lower than the glass transition temperature (Tg) of the polymer used as yarn, fiber or filament, some degree of polymer embrittlement is achieved, thereby preventing the fabric from being damaged. At least the operation of defibrating the base filaments is increased or accelerated.

  Basic filament damage can also be avoided by making the roughness of dry ice, air-sand mixture or frozen water relatively small.

  Use in the form of snow instead of pellets will not damage the basic filament in achieving defibration because the snow particle size is small and / or the roughness is small ("softer"). This is particularly preferable because it is gentle to the filament.

  As a result of the sublimation action of dry ice in the process of treating the defibrating starting fabric, the volume of carbon dioxide rapidly expands from the solid to the gaseous state by about 600 to 800 times its original volume. Dry ice enters between the basic filaments, which likewise at least increases or facilitates defibration of the fabric into the basic filaments.

  The basic filament configuration when looking at the cross section of the yarn, fiber or filament may be, for example, a sheath-core structure or an orange segment or a pie structure. It is particularly preferred to use a defibrating starting fabric with a pie structure, in which the basic filament has a pi structure, preferably with 2 to 64 segments depending on the diameter of the filament.

Preferred embodiments of the invention are subject matter of the dependent claims.
It is advantageous to use a fibrous nonwoven web as the starting fabric that can be defibrated. The fibrous nonwoven web used is a staple fiber nonwoven or spunbonded fibrous nonwoven web containing continuous filament fibers or composite fibers obtained by melt spinning or solvent-spinning processes (Spunbonded fibrous nonwoven web) is preferred.

The use of melt spun spunbonded fibrous nonwoven webs has the advantages of having no solvent to remove and being economical to use compared to solvent spunbonded fibrous nonwoven webs. Is preferred.
The defibrating starting fabric used is preferably a preconsolidated fibrous nonwoven web, which is pre-solidified thermally, mechanically and / or chemically, more preferably thermally. ing.

  The yarns, fibers or filaments of the fabric preferably have at least two basic filaments selected from polymer pairs or polymer blends optionally combined with polyolefins, polyesters, polyamides and / or polyurethanes.

  Preferred polyolefins are, for example, polyethylene or polypropylene, and preferred polyesters are, for example, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, recycled polyester, polylactic acid or copolyester, and preferred polyamides are, for example, nylon-6, nylon- 12, nylon 6,6 or copolyamide.

In order to work with high efficiency, the treatment with the dry ice, the frozen water or the air-particle mixture on the surface of the defibrating starting fabric, more specifically the impact is preferably between 0.1 ° and It is carried out at an incident angle of 180 °, particularly preferably 45 ° to 135 °, more preferably 90 °.
Advantageously, the kinetic energy of the particles of dry ice, frozen water or air-particle mixture is not less than 0.4 Joules. The mass and velocity of the particles are selected so that no visible damage occurs in the fabric or no holes are made in the fabric.

The flow rate of dry ice, frozen water or air-particle mixture is advantageously in the range of 30 kg / h to 70 kg / h, preferably in the range of 30 kg / h to 50 kg / h.
The particles of dry ice, frozen water or air-particle mixture preferably have an average size of 10 μm to 30 mm, more preferably 0.1 mm to 10 mm when reaching the surface of the defibrating starting fabric.
The impact on the surface of the defibrating starting fabric with dry ice, frozen water or air-particle mixture is from 2.5 m / min to 12.5 m / min at the exit nozzle at a speed of 100 m / s to 500 m / s. More preferably, it is carried out in combination with a forward speed of 2.5 m / min to 5 m / min.
The defibration to the basic filament is advantageously carried out at a pressure of 0.5 bar to 16 bar, preferably 0.5 bar to 6 bar, more preferably 0.5 to 2 bar.

The present invention further provides an apparatus that is particularly suitable for the method of the present invention described above and that allows the method to be easily implemented.
An apparatus for defibrating a fabric comprising at least partially defibrated yarns, fibers or filaments comprising at least two elementary filaments, more particularly according to the method according to claims 1-7. Can be directed to a defibrating starting fabric and can be impacted with dry ice, frozen water or an air-particle mixture on at least one defibrating surface of the defibrating starting fabric Having at least one outlet nozzle.
Advantageously, at least one outlet nozzle has an internal structure for pulverizing dry ice, frozen water or an air-particle mixture therein.

The surface of a 70:30 PET / PA6 segmented pie fiber spunbonded fibrous nonwoven web, precured thermally and defibrated at 2 bar using dry ice pellets according to the present invention. It is a scanning electron micrograph of the principal part expanded 100 times. 70/30 PET / PA6 segmented pie fiber (not thermally presolidified) spunbonded fibrous nonwoven defibrated at 2 bar using dry ice snow according to the present invention It is the scanning electron micrograph of the principal part which expanded the surface of the web 100 times. 70/30 PET / PA6 segmented pie fiber (not thermally pre-cured) spunbonded fibrous nonwoven defibrated at 1 bar using dry ice snow according to the present invention It is the scanning electron micrograph of the principal part which expanded the surface of the web 100 times.

The subject matter of the present invention will now be described more specifically with reference to examples and drawings.
Scanning electron micrographs were obtained with an acceleration voltage of 20 kV using a JEOL JSM-6480LV low-voltage scanning electron microscope.

  Example 1 comprises a spunbond fibrous nonwoven web, more specifically a 16 segment pie structure with alternating polyethylene terephthalate / nylon-6 (PET / PA6) at a weight ratio of 70:30. The operation comprises impacting dry ice pellets on a melt-spun spunbonded fibrous nonwoven web composed of continuous bicomponent filaments.

  For this reason, the spunbonded fibrous non-woven web is subjected to a minimum needle stab processing to such an extent that it can be conveyed, and thus is subjected to a mechanical agglomeration to a minimum. Furthermore, the spunbonded fibrous nonwoven web is pre-solidified thermally for 30 seconds at a temperature of 150 ° C. and a pressure of 300 bar by a heatable platen press.

To unwind the filaments of the spunbond fibrous nonwoven web, the spunbond fibrous nonwoven web is placed at a 90 ° angle below the outlet nozzle of the dry ice pellets. In terms of shape, the nozzle is a wide slot nozzle with a rectangular exit area measuring 50 mm × 4 mm. Although this nozzle is used to distribute energy over the widest possible area, a circular nozzle can basically be used in this embodiment.
The spunbond fibrous nonwoven web is then impacted vertically with dry ice pellets.

Polyethylene terephthalate (crystalline) has an ISO75HDT / A (1.8 MPa) glass transition temperature (Tg) of about 80 ° C., an ISO11359 melting temperature of about 255 ° C., and nylon-6 ISO75HDT / A (1.8 MPa). The glass transition temperature (Tg) is about 65 ° C. and the ISO 11359 melting temperature is about 220 ° C.
Dry ice pellets are generally 3 mm in diameter and 1 cm in length. When the density of dry ice is 1.56 g / cm ³ , the weight of one pellet is about 0.11 g (mass m).

The impact by the dry ice pellets is performed at a flow rate of 50 kg / h and the speed (v) of each individual dry ice pellet is 300 m / s.
Therefore, the kinetic energy of dry ice pellets (E _kin = 0.5 mV ² = 0.5 × 0.11 × ^{10 −3} kg × (300 m / s) ² = 4.95 kgm ² / s ² ) is 4.95 Joules It is.

The separation distance between the exit nozzle and the surface of the defibrating starting fabric is between 10 mm and 100 mm, preferably between 25 mm and 75 mm.
The pressure of the dry ice pellets when impacting the spunbond fibrous nonwoven web is 2 bar. The advance speed of the outlet nozzle is 5 m / min.

  FIG. 1 shows a scanning electron micrograph of the spunbond fibrous nonwoven web of Example 1.

In Example 2, in contrast to Example 1, dry ice snow having a particle size of about 0.1 mm × 0.5 mm is used instead of dry ice pellets. The weight of the dry ice snow is 0.0105 g (mass m).
The impact by dry ice snow is carried out at a speed (v) of 300 m / s.
Therefore, the kinetic energy of dry ice snow (E _kin = 0.5 mv ² = 0.5 × 0.0105 × 10 ⁻³ kg × (300 m / s) ² = 0.4725 kgm ² / s ² ) is 0.4725. Jules.

In addition, the spunbonded fibrous nonwoven web composed of bicomponent filaments made of polyethylene terephthalate / nylon-6 with a weight ratio of 70:30 and having a 16 segment pie structure is the same as the procedure of Example 1. In contrast, it is not thermally pre-solidified. In other respects, the method is performed similarly to the conditions of Example 1 except that dry ice snow is used instead of dry ice pellets.
FIG. 2 shows a scanning electron micrograph of the spunbond fibrous nonwoven web of Example 2.
The filament is more mobile than that of Example 1 because it is not thermally pre-solidified.

  The method according to Example 3 similarly utilizes a bicomponent filament spunbonded fibrous nonwoven web of polyethylene terephthalate / nylon-6 having a weight ratio of 70:30 and having a 16 segment pie structure. As in Example 2, this method is performed using dry ice snow instead of dry ice pellets. In contrast to Example 2, the dry ice snow pressure in Example 3 on impact of a spunbonded fibrous nonwoven web is only 1 bar instead of 2 bar.

FIG. 3 shows a scanning electron micrograph of the spunbond fibrous nonwoven web of Example 3.
This method according to Example 3 shows that defibration to the basic filament can still be carried out very easily even at a pressure of 1 bar.

Claims (9)

  A method of forming a fabric comprising at least partially defibrated yarn, fibers or filaments formed from at least two elementary filaments, wherein the defibrated starting fabric is dried ice, frozen water or air- The particle mixture is defibrated at least partly to the basic filament by treatment at a temperature at least 20 ° C. to 30 ° C. below the glass transition temperature (Tg) of the polymer used as yarn, fiber or filament, more specifically by impact treatment. A method comprising:   The method of claim 1, wherein a fibrous nonwoven web, more specifically a spunbonded fibrous nonwoven web, is used as a defibrating starting fabric.   3. A method according to claim 1 or 2, wherein a pre-solidified fibrous nonwoven web is used as a starting fabric that can be defibrated.   4. The yarn according to claim 1, wherein the yarn, fiber or filament has at least two elementary filaments selected from polymer pairs or blends obtained in any desired combination from polyolefins, polyesters, polyamides and / or polyurethanes. The method according to claim 1.   The treatment on the surface of the defibrating starting fabric with the dry ice, the frozen water or the air-particle mixture, more specifically the impact treatment is 0.1 ° to 180 °, preferably 45 ° to 135. 5. A method according to any one of the preceding claims, carried out at an angle of incidence ([alpha]) of [deg.], More preferably 90 [deg.].   The method according to any one of claims 1 to 5, wherein the kinetic energy of the particles of the dry ice, the frozen water or the air-particle mixture is 0.4 Joules or more.   7. The defibrating to the basic filament is carried out at a pressure of 0.5 bar to 16 bar, preferably 0.5 to 6 bar, more preferably 0.5 to 2 bar. The method according to one item.   A defibrating starting fabric comprising at least partially defibrated yarns, fibers or filaments comprising at least two elementary filaments, more particularly for defibrating by the method according to claims 1-7. At least one outlet capable of being directed to the fabric and capable of impacting at least one defibrable surface of the starting fabric with dry ice, frozen water or an air-particle mixture A device with a nozzle.   9. An apparatus according to claim 8, wherein an internal structure for pulverizing the dry ice, the frozen water or the air-particle mixture is located in at least one outlet nozzle.

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