EP0814188A1 - Nonwoven cloth made of very fine continuous filaments - Google Patents

Abstract

A non-woven fabric web of continuous filaments which may or may not be crimped, is made by direct controlled spinning and has a weight of 5-600 g/m<2>, formed after laying composite filaments that are separable in the longitudinal direction. The composite filaments have a titre of 0.3-10 dTex and are each made up of at least three elementary filaments made from at least two different materials, having between them at least one plane of separation or cleavage, each elementary filament having a titre of 0.005-2 dTex and the ratio between the cross sectional area of each elementary filament and the total cross sectional area of the unitary filament being 0.5- 90%.

Description

The present invention relates to the field of textile products and their applications, and relates to a nonwoven web of very fine continuous filaments or micro-filaments.

The present invention aims in particular to broaden the traditional scope of nonwovens by giving them physical properties and characteristics, more particularly textile and mechanical, similar to those of woven and knitted textile products, while retaining the advantageous properties and characteristics of nonwovens of continuous filaments.

Synthetic textile fibers are already known, generally designated by the term "Shin-Gosen", whose characteristics of touch and appearance are very close to natural fibers.

These known fibers are obtained by spinning techniques which make it possible to obtain ultra-fine fibers or microfibers, of various sections, and of variable polymeric constitution. After spinning, these fibers are transformed by known techniques of weaving or knitting and treated according to more or less complex finishing techniques.

An object of the present invention is to obtain nonwoven products having characteristics and properties at least equal to those of woven or knitted products obtained by means of the above-mentioned ultra-fine fibers, while applying manufacturing techniques which are clearly more efficient and less costly. , resulting in greater flexibility in the variability of the nature and properties of the filaments, consolidation methods and properties of the products obtained.

To this end, the subject of the present invention is a nonwoven web of continuous filaments, crimped or not, obtained by means of a controlled direct spinning process, having a grammage between 5 g / m ² and 600 g / m ² and formed, after lapping, of composite filaments separable in the direction of their length, characterized in that said composite filaments have a count between 0.3 dTex and 10 dTex and are formed, each, by at least three elementary filaments in at least two different materials and comprising between them at least one plane of separation or cleavage, each elementary filament having a titer between 0.005 dTex and 2 dTex and the ratio between the area of the cross section of each elementary filament and the total area of the cross section of the unitary filament being between 0.5% and 90%.

The invention will be better understood from the description below, which relates to preferred embodiments, given by way of nonlimiting examples, and explained with reference to the appended schematic drawings, in which FIGS. 1 to 7 represent cross sections of continuous composite filaments according to the invention, before separation into elementary filaments.

In general, the invention relates to a nonwoven web of continuous filaments, crimped or not, obtained by means of a controlled direct spinning process, having a grammage between 5 g / m ² and 600 g / m ² and formed, after lapping, separable composite filaments.

According to the invention, said composite filaments have a titer between 0.3 dTex and 10 dTex and are each formed by at least three elementary filaments made of at least two different materials and comprising between them at least one separation plane or cleavage, each elementary filament having a titer between 0.005 dTex and 2 dTex and the ratio between the cross-sectional area of each elementary filament and the total cross-sectional area of the unitary filament being between 0.5% and 90 %.

Advantageously, the composite filaments have a titer greater than 0.5 dTex and each elementary filament has a titer less than 0.5 dTex.

According to a preferred embodiment of the invention, the composite filaments have a titer between 0.6 dTex and 3 dTex and the elementary filaments have titer between 0.02 dTex and 0.5 dTex.

Given the titles of elementary filaments, the sheet obtained can be designated as being a nonwoven sheet of continuous micro-filaments.

Advantageously, the nonwoven web is, after the controlled operations of extrusion / spinning, drawing / cooling and coating, subjected, simultaneously or successively, to operations of binding and consolidation by means of means (s ) mechanical (s), such as intense needling, the action of jets of pressurized fluid, the action of ultrasound and / or mechanical friction, of thermal means (s), such (s) as boiling water, steam or microwaves or chemical means (s), such as treatment with active blowing chemical agents for at least one of the materials composing the composite filaments, the composite filaments being at least partially separated into their elementary filaments during the said binding and consolidation operations.

As shown in the figures of the appended drawings, the various polymeric materials forming the composite filaments are distributed in distinct zones in the cross section of the latter, so as to allow their separation into elementary filaments each corresponding, in cross section, to one of said zones.

In order to allow easy separation of the composite filaments into elementary filaments, while allowing initial direct contact between said elementary filaments to form said composite filaments, the various polymer materials constituting the composite filaments are advantageously immiscible and / or incompatible with one another. made by nature or following treatment of at least one of said polymeric materials.

According to a preferred embodiment of the invention, the group of polymeric materials forming the elementary filaments is chosen from the following groups: (polyester / polyamide); (polyamide / polyolefin); (polyester / polyolefin); (polyurethane / polyolefin); (polyester / polyester modified with at least one additive); (polyamide / polyamide modified by an additive); (polyester / polyurethane); (polyamide / polyurethane); (polyester / polyamide / polyolefin); (polyester / polyester modified with at least one additive / polyamide): (polyester / polyurethane / polyolefin / polyamide).

According to a first alternative embodiment of the invention. shown more particularly in Figures 1 to 4 of the accompanying drawings, the composite filaments have, in cross section, a configuration of the zones representing the cross sections of the various elementary filaments, in the form of orange wedges or sectors of pie chart.

Said districts or sectors, forming the pattern of the cross section of the composite elements, may have different dimensions, thus generating, after separation and separation of the initial composite filaments, elementary filaments of clearly different titles.

In order to facilitate the separation of the composite filaments into elementary filaments, said composite filaments may comprise a longitudinal tubular hollow cavity, centered or not relative to the median axis of said composite filaments.

Indeed, this arrangement eliminates the intimate contact between the edges of the elementary filaments formed by the interior angles of the quarters or sectors, before separation of the composite filaments, and the contact at this level of different elementary filaments made of the same polymer material.

According to a second alternative embodiment of the invention, shown in FIGS. 4 and 5 of the accompanying drawings, the elementary filaments are integrated into an enveloping matrix of an easily fractionable or dissolvable material, the material of said matrix also being present in the interstices separating said elementary filaments or be replaced by another dissolvable or incompatible polymeric material with respect to the polymeric material forming the elementary filaments (see FIG. 3).

In this case, the contours of the cross sections of the elementary filaments can be any, and in particular be in the form of orange wedges or sectors of pie chart, the enveloping matrix forming the receiving compartments of said quarters or sectors as well as a outer envelope surrounding all of said districts or sectors (see Figure 4).

According to a third alternative embodiment of the invention, shown in Figures 6 and 7 of the accompanying drawings, the outer contours of the cross sections of the composite filaments have a multilobed configuration, defining several sectors or zones each corresponding to an elementary filament .

According to a particularly preferred characteristic of the invention, the elementary filaments have, in cross section, a configuration in the form of a daisy whose pistil is formed by an elementary filament and whose petals are formed by the other elementary filaments forming each of said composite filaments .

In order to further consolidate the structure of the nonwoven web, the composite filaments may exhibit a latent or spontaneous crimp resulting from an asymmetry of behavior of said filaments with respect to their longitudinal median axis, said crimp being activated or accentuated, where appropriate, by an asymmetry of the geometry of the configuration of the cross section of said composite filaments.

As a variant, the composite filaments may exhibit a latent or spontaneous crimp resulting from a differentiation of the physical properties of the polymeric materials forming the elementary filaments during the spinning, cooling and / or drawing operations of the composite filaments resulting in generated distortions by asymmetrical internal stresses with respect to the longitudinal median axis of said composite filaments, said crimp being activated or accentuated, if necessary, by an asymmetry of the geometry of the configuration of the cross section of said composite filaments.

The composite filaments can have a latent crimp which is activated by heat, mechanical or chemical treatment before the formation of the nonwoven web.

The crimp can be accentuated by a complementary treatment of the consolidated or unconsolidated sheet, of the thermal type (tunnel oven, boiling water, steam, heating drum, microwave, infrared waves) or of the chemical type, with possible controlled retraction. of the tablecloth.

In order to further consolidate the nonwoven web, it can be provided that the elementary filaments are strongly entangled, during or after the division of the composite filaments, by mechanical means (needling, jets of fluid under pressure) acting mainly in one direction perpendicular to the plane of the tablecloth.

The initial composite filaments can be obtained, for example, by electrostatic, mechanical and / or pneumatic deflection (a combination of at least two of these types of deflection is possible) and projection onto an endless moving belt and can be entangled mechanically by needling (on one or two sides with needles and under adequate perforation conditions depending on the properties required for the nonwoven web) or by the action of jets of pressurized fluid, loaded or not with solid microparticles, possibly after calendering.

According to an embodiment of the invention, the sheet is composed of several superimposed nonwoven layers.

According to a first alternative embodiment, each layer consists of filaments originating from a single die.

According to a second variant embodiment of the invention, at least one layer consists of filaments originating from at least two separate dies, said filaments being mixed during the stretching phase, before lapping.

Likewise, provision may be made for at least one of the layers constituting said layer to be formed by means of filaments different from those of at least one other of said constituent layers.

The operations of entangling and separating the composite filaments into elementary filaments can be carried out in the same process step and with the same device, the more or less complete separation of said elementary filaments being able to be completed by an additional operation more targeted at said separation .

The cohesion and the mechanical resistance of the nonwoven web can also be appreciably increased, by providing for bonding of the elementary filaments with one another by one or more of them formed from a polymeric material. lower melting point, by calendering by means of smooth or engraved heated rollers, by passage through a hot air tunnel oven, by passage over a through hot air drum and / or by application of a binding agent contained in a dispersion , in solution or in powder form.

The consolidation of the sheet can, as a variant, also be carried out, for example by hot calendering, before any separation of the unitary composite filaments into elementary filaments or micro-filaments, said separation being carried out after consolidation of the sheet.

In addition, the structure of said sheet can also be consolidated by a chemical treatment (as described for example in French patent n ° 2,546,536 in the name of the applicant) or thermal resulting in a controlled retraction of at least part of the elementary filaments, after having, if necessary, separated them, resulting in a retraction of the web in the direction of its width and / or in the direction of its length.

Furthermore, and according to an additional characteristic of the invention, the nonwoven web may be subjected, after consolidation, to a binding or finishing treatment of the chemical type, such as an anti-pilling, hydrophylizing, anti-static treatment. , improvement of fire resistance and / or modification of touch or luster, of the mechanical type, such as scraping, sanforizing, emery or passage through a trumbler, and / or of the type modifying the external appearance such as dyeing or printing.

• composante apparente des éléments de revêtement intérieur des véhicules automobiles,
• textile pour l'ameublement intérieur et extérieur,
• textile pour la fabrication des dessus de doublures et des couches intercalaires de composants de chaussures et pour la confection des parties extérieures et des doublures de bagages et de sacs,
• textile pour la fabrication de pièces de vêtements ou de doublures de pièces de vêtements,
• textile pour la fabrication de chiffons et de produits composites de nettoyage domestique et industriel, ainsi que de nettoyage de salles blanches,
• substrat pour la réalisation de filtres ou de membranes filtrantes,
• produit pour la réalisation de cuirs synthétiques.

The nonwoven web described above can in particular be used as:

• visible component of the interior coating elements of motor vehicles,
• textiles for interior and exterior furnishings,
• textile for the production of uppers for linings and interlayers for shoe components and for the manufacture of exterior parts and linings for luggage and bags,
• textile for the production of pieces of clothing or linings of pieces of clothing,
• textiles for the production of rags and composite products for household and industrial cleaning, as well as for cleaning clean rooms,
• substrate for the production of filters or filtering membranes,
• product for the production of synthetic leathers.

The invention will now be described in more detail using several practical embodiments indicated without limitation.

Example 1 :

A sheet of two-component polyethylene terephthalate / polyamide 6 continuous filaments is produced.

The materials used have the following characteristics: POLYESTER POLYAMIDE Nature Polyethylene terephthalate Polyamide 6 Intrinsic viscosity 0.64 2.6 * TiO ₂ 0.4% 1.7% Fusion point 256 ° C 222 ° C Melted viscosity 190 Pa.s at 290 ° C 170 Pa.s at 265 ° C Origin Rhone Poulenc Company Nylstar Company * Viscosity: concentration 1% in sulfuric acid at 96% and 20 ° C.

As shown in Figure 8 of the accompanying drawings, the spinning unit 1 consists of two chambers, one of which is located in the axis of said unit (PA6 spinning) and the second, of annular shape, surrounds the first (PET spinning).

• deux plaques de répartition 2 destinées à croiser les flux des deux chambres.
• trois plaques 3 dédiées à la distribution proprement dite.

Polymers are distributed by five intermediate plates, including:

• two distribution plates 2 intended to cross the flows of the two chambers.
• three plates 3 dedicated to the distribution proper.

The two distribution plates allow distribution both circular and radial.

The stacking of the three final distribution plates allows an alveolar supply of each of the holes of the die. Each of said holes thus has its own supply circuit and makes it possible to spin a unitary composite filament.

The die itself is made up of 180 capillary holes with a diameter of 0.28 mm and a length of 0.56 mm. A schematic representation of an orifice of such a die is reproduced in Figure 10 of the accompanying drawings.

The extrusion temperatures of the two polymers are respectively 295 ° C for PET and 255 ° C for PA6, the spinning boat itself being at a temperature of 278 ° C, the spinning speed is about 4,500 m / min and the flow rate per die hole of 0.7 g / min (0.35 g / min per polymer).

The drying of PA6 and the supply of the extruder are carried out under a nitrogen atmosphere and the polymer transfer circuits to the die are designed so that the residence and transport times of said polymers are sufficiently short to avoid any significant deterioration of these.

The manufacturing process for this sheet is similar, as regards the conditions of cooling, drawing and coating, to that described in French patent n ° 74 20254.

The nonwoven ply obtained has a grammage of 120 g / m ² and consists of continuous non-crimped filaments having a titer of 1.6 dTex and having in cross section a configuration in orange wedges with a central orifice, said districts or sectors being alternately composed of one of the two aforementioned polymer materials and in direct contact with the adjacent districts or sectors (structure of the section comparable to that shown in FIG. 2 of the accompanying drawings).

Each composite filament consists of six elementary polyethylene terephthalate filaments with a titer of 0.15 dTex and six elementary polyamide 6 filaments with a titer of 0.11 dTex, resulting in a weight ratio of polyethylene terephthalate / polyamide 6 of 60/40.

After coating, the aforementioned nonwoven layer is subjected to the action of jets of fluid (water) under pressure with a view to achieving the separation of the composite filaments into elementary filaments, as well as the entanglement and binding of the latter.

The conditions and the means of carrying out this hydraulic tying operation are substantially similar to those described in French Patent No. 2,705,698 in the name of the applicant.

More precisely, said hydraulic binding consists, successively, of a passage of the nonwoven ply under a first wetting ramp, of a wringing of the wetted ply (by passage between two pressure rollers or by suction, for example) and finally by a passage of the ply at the level of the three successive sets of hydraulic binding on a suction drum, said assemblies acting respectively on the front, back and front sides of the sheet and each comprising three bars or lines of jets spaced 0.6 mm apart.

During the hydraulic tying operation, the nonwoven web moves on a metallic mesh of 80 mesch (80 threads / 2.54 cm) with 70% opening. Bed processing speed in this case is about 15m / min.

The conditions for adjusting the above-mentioned hydraulic tying assemblies are as follows: 1st set - Face RECTO Line of jets Line 1 Line 2 Line 3 Nozzle diameter (µ) 100 100 100 Pressure (bars) 120 180 180 2nd set - Face VERSO Line of jets Line 1 Line 2 Line 3 Nozzle diameter (µ) 120 120 120 Pressure (bars) 230 230 230 3rd set - Face RECTO Line of jets Line 1 Line 2 Line 3 Nozzle diameter (µ) 120 120 120 Pressure (bars) 230 230 230

At the outlet of the third set of hydraulic binding, the nonwoven web is wrung by compression between two pressure rollers, dried on a through air drum heated to 160 ° C and, finally, wound.

The specific characteristics and properties of this sheet are as follows: appearance and texture of a "flannel" type fabric, high breaking load and tear resistance characteristics, good drapability and good abrasion resistance.

The tablecloth obtained by the above-mentioned process, in fact forming a nonwoven fabric, can be advantageously used, after dyeing or printing and possibly hot embossing, as an interior covering for a car roof or a wall covering.

Example 2 :

A nonwoven web of continuous filaments is produced according to a process similar to that described in Example 1, said web being subjected to a hydraulic bonding identical to that described above.

The sheet obtained, however, has a grammage of 130 g / m ² and is subjected, following the hydraulic bonding, to a calendering by points by means of two heated metal rollers, namely a roll engraved at 232 ° C and a smooth roll at 215 ° C (pressing force: 50daN / cm of width; speed: 15m / min; 52 points / cm ² ; percentage of bonded surface: 13%).

This additional treatment of the ply leads to an increase in the resistance of the latter to deformation and abrasion.

The sheet obtained can advantageously be used for pigment printing or, after dyeing, as an apparent coating of door panels for motor vehicles, coating of injected or molded parts intended to be mounted in the cockpits of vehicles, for the manufacture of inner linings for shoes or for making workwear.

As a variant, said tablecloth can also be used, after printing (in particular of the "fixed-washed" type), for the production of drapes or curtains for interior furnishings.

Example 3 :

A sheet of continuous curly composite filaments is produced, composed of polyethylene terephthalate / polyamide 66 polymer materials, present in identical weight proportions.

The PET used is identical to that of Example 1.

Polyamide 66 (PA66) is of the type known under the designation 44AM30 by the company Rhone Poulenc (melt viscosity: 170 Pa.s and IV 137).

The melting and spinning temperatures are 285 ° C. for the two polymers and the title pumps used have a flow rate of 10 cm ³ per revolution.

The supply and distribution system of the spinning unit is similar to that of Example 1.

Each die has 180 holes with an outside diameter of 1.35 mm and an inside diameter of 1.0 mm off center. This arrangement makes it possible to end up with an annular slot, the width of which varies as a function of the circumferential position (for example of the half-circumference) and which can be produced by forecasting and the cutting of two half-discs of different radii, ending in an annular slot of which a half-circumference has a width of 0.15 mm and of which the other half-circumference has a width of 0.2 mm (see FIG. 9 of attached drawings).

The cooling system located under the die is annular in shape and blows fresh air at 17 ° C and with 80% RH, at a speed of 0.8 m / s.

The stretching and tablecloth system is similar to that described in French patent n ° 74 20254 in the name of the applicant.

The continuous spun composite filaments have twelve crimps per centimeter and a crimp rate of 180%.

The nonwoven ply obtained has a grammage of 140 g / m ² and is made up of composite filaments having a titer of 1.6 dTex and having in cross section an orange quarter configuration with an off-centered orifice, resulting in an asymmetrical behavior of the composite filament. and the formation of elementary filaments having different titles.

Said ply is subjected to a hydraulic bonding (use of the same assemblies as those used in Example 1, but with a pressure of 180 bars for the second and third assemblies), then to a chemical shrinkage treatment as described in particular in the French Patent No. 2,546,536 in the name of the plaintiff.

The bath is brought to a temperature of 18 ° C and has a formic acid level of 64%.

The contact time of the tablecloth with the bath is approximately 25 seconds and the soaking of the tablecloth is followed by successive operations of rinsing with water at room temperature, spinning and drying at 120 ° C.

An impregnation of this sheet is then carried out with a solution of polyurethane in dimethylformamide (polyurethane of type 025 / 70H from the company COIM, present at a rate of 14%), then coagulation of the polyurethane by passing the sheet through a bath. dimethylformamide / water (20/80) at 60 ° C.

After drying, a deposit of approximately 16% of dry polyurethane is obtained relative to the fibrous mass of the sheet.

Finally, the sheet is also subjected, consecutively, to darning and dyeing operations, in particular of the high temperature "Jigger" type.

The nonwoven product, weighing 172 g / m ² , obtained by the process described above has properties and an appearance similar to leather and can be advantageously used for the manufacture of shoes, leather goods and luggage and luggage. seat and upholstery coverings, for the production of seat coverings and car interior interiors.

Example 4 :

A sheet of continuous filaments is produced having a fibrous constitution identical to that described in Example 3, but showing a latent crimp.

In order to generate a large crimp, the unitary composite filaments are advantageously spun at a speed of around 3,200 m / min and subjected, after lapping, to a hydraulic binding operation under conditions substantially similar to those described in the example. 3.

Following the hydraulic bonding, the sheet is subjected to a drying and heat treatment operation between 160 ° C and 180 ° C (temperature below the yellowing temperature of the polyamide polymer) resulting in the revelation or activation of the latent crimp and shrinkage of said sheet, the time of submission of the sheet to the heat treatment being less than one minute.

For this purpose, a pliers ream is used which grips said ply by pinching at each longitudinal lateral edge, said pliers having a configuration in top view in a V shape (narrowing of the spacing of the lateral pliers in the direction of the advancement of the water table). By the implementation of such a clamped ream (having a narrowing in the direction of its exit) and by carrying out a supercharging of the ply in the longitudinal direction at the entry of the ream, one obtains a retraction of said ply also along its length.

The retraction rate of the free filaments at 180 ° C is approximately 50% to 60%, which results in a retraction rate for the web of between 12% and 15% (in the longitudinal direction and in the transverse direction) and an increase in grammage between 30% and 35%.

The sheet thus retracted is then subjected to additional treatments identical to those described in the context of Example 3 (from the impregnation using a polyurethane solution) and can be used in applications similar to those described in this example.

Example 5 :

A web of polyethylene terephthalate / polybutylene terephthalate bicomponent continuous filaments is produced.

The structure of the spinning unit used in this example is substantially similar to that of the spinning unit used in Example 3, with the presence of two distribution plates intended to cross flows and three distribution plates, the orifices are shaped and grouped in the form of daisies.

The distribution system is produced on the basis of a coaxial distribution of the polymers, but using a multi-lobed die. The heart, or the central element, of each daisy structure being supplied by the distribution circuit of two PBTs and the eight lobes of each daisy structure being supplied with PET.

The PET used is identical to that used in the context of Example 1, while being added in a small percentage of silicone oil of the organosiloxane type (approximately 0.3%).

The PBT used is of the type known under the designation TQ9 / 04 from the company ENICHEM, has a melt viscosity of 290 Pa.s at 265 ° C. and is charged with 0.4% of TiO ₂ .

The extrusion temperatures are respectively 290 ° C (PET) and 260 ° C (PBT) and the temperature of the spinning boat is approximately 280 ° C.

The annular cooling device blows air at 20 ° C and 75% RH, with a speed of 1.2 m / s.

The spinneret / drawing nozzle distance is 1.1 meters for a spinning speed of 5,600 m / min.

The flow rate per die hole is 0.9 gr / min for PET and 0.11 gr / min for PBT.

The nonwoven ply obtained has a grammage of 145 g / m ² and consists of continuous non-crimped filaments having a titer of 1.8 dTex and having in cross section a daisy-like configuration in which the pistil is formed by an elementary cylindrical filament central in polybutylenetrephthalate (title 0.2 dTex) and the petals are formed by elementary filaments in polyethylene terephthalate (title 0.2 dTex), with elongated elliptical section, arranged circumferentially around said central elementary filament by being adjacent to the latter at the level of one of the ends of the ellipse delimiting the contour of said peripheral elementary filaments in cross section (see FIG. 7).

Said peripheral elementary filaments with an elongated ellipse section advantageously consist of polyethylene terephthalate added with silicone as described in particular in French patent No. 2,657,893 in the name of the applicant.

The injected silicone (approximately 0.3% by weight relative to the polyethylene terephthalate) serves as a spinning lubricant for the peripheral elementary filaments and, by partially migrating at least partially on the surface of said peripheral elementary filaments forms the interfaces between the latter and the elementary filament central, which significantly facilitates the separation of composite filaments into elementary filaments (energy required for lower separation). However, the level of silicone must be relatively limited so as not to disturb subsequent treatments (in particular the finishing), dyeing or printing.

After the formation of the nonwoven web of composite continuous filaments, the latter is subjected to mechanical needling, followed by hydraulic bonding, resulting in at least partial separation of the various elementary filaments.

Said sheet is then subjected to a punctual calendering at a temperature between the melting temperatures of the two polymers, that is to say between 256 ° C (melting temperature of PET) and 226 ° C (melting temperature of PBT ), so as to merge the PBT and create solid point bonds between the elementary PET filaments.

The resulting nonwoven product can be used, after pigmentary printing, as a substrate for the manufacture of cushions, garden chairs, parasols and table cloths.

The aforementioned nonwoven product can also be used, after dyeing or printing (in particular by a "fixed-washed" type process) for the production of interior coatings for motor vehicles, uppers (uppers) for sports and leisure shoes, luggage or leather goods.

Example 6 :

A web of three-component continuous filaments formed from polyethylene terephthalate, polyamide 6 and polypropylene is produced with respective total titers of 1.08 dTex, 1.08 dTex and 0.24 dTex.

The spinning unit consists of an annular chamber for polypropylene and two symmetrical axial chambers for polyamide 6 and polyethylene terephthalate.

The polymer distribution system is composed of three flow crossing plates and the separation system is composed of three cellular distribution plates, similar to those used in the context of Example 3.

The polypropylene of MFI 25 is extruded at 250 ° C. and the conditions for extruding polyamide 6 and polyethylene terephthalate are identical to those of Example 1.

In addition, the polypropylene is loaded with titanium oxide, introduced at the rate of 1% at the feed to the extruder, and the spinning speed is of the order of about 5000 m / min.

The nonwoven ply obtained has a grammage of 90 g / m ² and consists of continuous curly composite filaments having a titer of 2.4 dTex and having in cross section a configuration in orange wedges with an off-centered orifice (see FIG. 3) .

The separation of the composite filaments into elementary filaments is carried out during a hydraulic bonding operation.

It should be noted that the incompatibility of the various constituent materials makes it possible to limit the energy necessary for separation (which is complete for a pressure at the level of the nozzles of the binding devices of approximately 100 bars). This limitation of the separation energy is further accentuated by the difference in the nature of the materials and the fact of the slight swelling of the polyamide 6 in the presence of water.

The sheet is then subjected to drying at 180 ° C. on a through air drum, during which the elementary polypropylene filaments undergo total or partial melting, depending on the contact time (greater than about 12 seconds). This fusion of the polypropylene filamentary component leads to an intimate connection between the elementary filaments of polyethylene terephthalate and polyamide 6.

The nonwoven product thus obtained simultaneously has a very absorbent structure, due to its high capillarity, and good resistance to repeated use in household and industrial cleaning and wiping applications. In addition, the aforementioned product withstands (in terms of structural cohesion and pilling) repeated washing with water at 50 ° and dry degreasing (possibility of repeated reuse of the product and economical use).

In addition, such a product, by virtue of its constitution in continuous filaments and of the excellent cohesion resulting from hydraulic bonding and thermobinding, has the advantage of not emitting fibrous particles during use. This property is very important for the use in cleaning substrate for clean rooms and in electronics.

Example 7 :

A sheet of 120 g / m ^{2 is produced,} consisting of bicomponent filaments of 1.6 dTex as defined in Example 3 and of monoconstituting polyester filaments of 1.6 dTex, spun together in the same die, with a proportion of 80%. polyamide 66 and polyethylene terephthalate curly biconstituated filaments and 20% pure uncrossed polyester terephthalate filaments, leading to a multi-layered structure after separation of the constituents of the biconstituent filaments under the action of high pressure water jets (identical to example 1).

This sheet is then subjected to a binding by punctual calendering using etched metal rollers, at a temperature of 238 ° C, and a counterpart made up of a smooth metal roller, at a temperature of 223 ° C. (Pressing force: 50daN / cm of width; speed of 22m / min; 55 points / cm ² ; percentage of bound surface: 17%).

There is also the possibility of introducing dispersed dyes in the form of master batches into the polyamide and polyethylene terephthalate polymer materials during extrusion in order to obtain mass-dyed products, the coloring of which has excellent resistance. to light and friction.

The two-component filaments and the single-component filaments can be extruded at the same die, or can be extruded at two separate successive dies, the extruded filaments then being mixed at the drawing station.

The nonwoven fabric obtained combines very good mechanical properties, in particular of tear resistance, with good properties of appearance, flexibility, drape and resilience, making it particularly suitable for making work clothes.

Example 8 :

Using the continuous crimped filaments described in Example 6, a nonwoven ply is produced directly by 120 g / m ² using a topping system in eight unitary plies of 15 grams each, successively deposited one on top of the other according to the method described in French patent n ° 74 20254. Between layers 4 and 5, a stabilized knitted textile weft knit of 20gr / m ² of polyamide 6 is introduced.

The laminate assembly is linked by a hydraulic tying device comprising successively high-pressure water jet ramps (250 bars) on both sides, leading to the separation of the strands and the entanglement of the microfilaments formed by the individual elementary filaments and of the cited textile reinforcement, in a very cohesive manner.

The three-layer assembly obtained is then dried at 180 ° C., in order to melt the polypropylene microfilaments which act as a binder.

The resulting nonwoven fabric can be dyed or printed by conventional methods and then treated in a tumbler, to improve feel and flexibility.

The properties of this fabric with flannel feel very favorably combine the mechanical characteristics, appearance, flexibility, drooping and resistance to abrasion, and the limitation of the bagging due to the textile reinforcement used, for the production of leisure clothes. such as sports jackets and jackets or indoor clothing such as dressing gowns.

Example 9 :

A sheet of bicomponent filaments as defined in example 3 is produced, but with a grammage of 32 g / m ² and linked by the hydraulic bonding process - in treatment on both sides (pressures identical to those used in example 1, with a running speed of 65 m / min). This nonwoven is coated by the point dusting technique (16 gr / m ² ) with a terpolyamide powder (PA66, 612), having a melting temperature of 120 ° (see on this subject DE-PS-3610029, example 1 ).

The product obtained has very good flexibility and good elasticity, and is resistant to dry degreasing. This product can be advantageously used as a fusible lining for clothing.

Example 10 :

A multi-layer web of total grammage 140 gr / m ^{2 is produced} formed of five layers (70 gr / m ² ) of filaments of the type of those produced in the context of Example 1 and five other layers (70 gr / m ² ) made up of bimetallic curly filaments, having a titer of 1.5 dTex and formed from polyethylene terephthalate and polybutylene terephthalate (such as those described in French Patent No. 2,705,698).

A hydraulic bonding is then carried out as described in the aforementioned French patent, followed by a smooth calendering between a hot roller at 225 ° C. (in contact with the face of the nonwoven with a constitution similar to that described in Example 1) and a cold roller at 125 ° C, at a speed of 18m / min and with a pressing force of 25 daN / cm of calender width.

The product obtained can advantageously be used in filtration applications, in particular for draining milk or filtering edible oil.

The characteristics and properties of the products obtained in the above examples 1 to 3 and 7 are summarized, in a synoptic manner, in the table of numerical values below: Measured Unit Method Example 1 Example 2 Example 3 Example 7 Surface mass g / m ² NFG 38013 120 130 140 120 Thickness mm NFG 38012 0.63 0.55 0.8 0.78 Breaking load sL / sT daN / 5cm NFG 07001 43.0 / 32.0 38.0 / 25.7 31.0 / 33.6 46.4 / 37.6 Isotropy - 1.34 1.48 0.92 1.23 Elongation sL / sT % NFG 07001 73/85 56.2 / 72.8 65.0 / 75.1 65.1 / 83.0 Load 3% sL / sT daN / 5cm NFG 07001 2.1 / 0.55 5.52 / 0.98 Load 5% sL / sT daN / 5cm NFG 07001 3.5 / 0.87 8.1 / 1.6 Load 15% sL / sT daN / 5cm NFG 07001 10.8 / 3.2 16.7 / 5.15 Breaking energy sL / sT J NFG 07001 41.5 / 25.3 28.8 / 19.2 Thermal shrinkage sL / sT % 180 ° -15mn - 0.6 / -0.4 - 1.5 / 0.2 - 0.1 / - 1.2 -1.1 / -1.4 CV mass% (5 x 5 cm) % 3.7 3.0 4.1 3.5 Tear initiated sL / sT daN NFG 07146 2.4 / 3.6 1.8 / 3.4 2.7 / 3.2 2.8 / 3.0 Specific load [(L + T) / 2] / areal mass daN / g / m ² 3.1 2.45 1.92 3.5 Initial module calc. → 1m (tangent load at 3%) MN / m 4.1 11.0 4.3 6.8 Abrasion resistance (9kPa) Pressure loss Number of cycles% Martindale ITF BS 5690 50,000 - 10.5 50,000 - 6.6 50,000 - 4.8 500,000 - 7.1 Porosity (5cm - 196 Pa) l / m ² / s NFG 07111 555 272 124 189 Drape coefficient NFG 07109 0.91 0.82 0.95 0.64

Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications remain possible in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims (33)

Nonwoven web of continuous filaments, crimped or not, obtained by a controlled direct spinning process, having a basis weight between 5 g / m ² and 600 g / m ² and formed, after lapping, of composite filaments separable in the direction of their length, characterized in that said composite filaments have a titer between 0.3 dTex and 10 dTex and are formed, each, by at least three elementary filaments in at least two different materials and comprising between them at least one plane separation or cleavage, each elementary filament having a titer between 0.005 dTex and 2 dTex and the ratio between the cross-sectional area of each elementary filament and the total area of the cross-section of the unitary filament being between 0.5 % and 90%. Tablecloth according to claim 1, characterized in that the composite filaments have a titer greater than 0.5 dTex and in that each elementary filament has a titer internal to 0.5 dTex. Tablecloth according to claim 1, characterized in that the composite filaments have a titer between 0.6 dTex and 3 dTex and in that the elementary filaments have titer between 0.02 dTex and 0.5 dTex. Tablecloth according to any one of claims 1 to 3, characterized in that after the controlled operations of extrusion / spinning, drawing / cooling and lapping, it is subjected, simultaneously or successively, to operations of tying and consolidation via mechanical means, such as intense needling, the action of jets of pressurized fluid, the action of ultrasound and / or mechanical friction, of means thermal (s), such as boiling water, steam or microwaves or chemical means (s), such as treatment with active blowing chemicals for at least one of the materials making up the composite filaments, the composite filaments being at least partially separated into their elementary filaments during said bonding and consolidation operations. Tablecloth according to any one of claims 1 to 4, characterized in that the various polymeric materials forming the composite filaments are distributed in distinct zones in the cross section of these latter, so as to allow their separation into elementary filaments each corresponding, in cross section, to one of said zones. Tablecloth according to any one of claims 1 to 5, characterized in that the various polymeric materials constituting the composite filaments are immiscible and / or incompatible with each other, due to their nature or following treatment of at least one of said polymeric materials. Tablecloth according to claim 6, characterized in that the group of polymeric materials forming the elementary filaments is chosen from the following groups: (polyester / polyamide); (polyamide / polyolefin); (polyester / polyolefin); (polyurethane / polyolefin); (polyester / polyester modified with at least one additive); (polyamide / polyamide modified by an additive); (polyester / polyurethane); (polyamide / polyurethane); (polyester / polyamide / polyolefin); (polyester / polyester modified with at least one additive / polyamide); (polyester / polyurethane / polyolefin / polyamide). Tablecloth according to any one of claims 1 to 7, characterized in that the composite filaments have, in cross section, a configuration of the zones representing the cross sections of the different elementary filaments, in the form of orange wedges or sectors of pie chart . Tablecloth according to claim 8, characterized in that the quarters or sectors, forming the pattern of the cross section of the composite elements, having different dimensions. Tablecloth according to any one of claims 8 and 9, characterized in that the composite filaments comprise a hollow tubular longitudinal cavity, centered or not relative to the median axis of said composite filaments. Tablecloth according to any one of claims 1 to 7, characterized in that the elementary filaments are integrated in an enveloping matrix in an easily fractionable or dissolvable material, the material of said matrix also being present in the interstices separating said elementary filaments. Tablecloth according to any one of claims 1 to 7, characterized in that the external contours of the cross sections of the composite filaments have a multilobed configuration, defining several sectors or zones. Tablecloth according to claim 12, characterized in that the elementary filaments have, in cross section, a configuration in daisy shape whose pistil is formed by an elementary filament and whose petals are formed by the other elementary filaments forming each of said composite filaments. Tablecloth according to any one of claims 1 to 13, characterized in that the composite filaments have a latent or spontaneous crimp resulting from an asymmetry of behavior of said filaments with respect to their longitudinal median axis, said crimp being activated or accentuated, the where appropriate, by an asymmetry of the geometry of the configuration of the cross section of said composite filaments. Tablecloth according to any one of claims 1 to 13, characterized in that the composite filaments have a latent or spontaneous crimp resulting from a differentiation of the physical properties of the polymeric materials forming the elementary filaments during the spinning, cooling and / or of stretching the composite filaments resulting in distortions generated by asymmetrical internal stresses with respect to the longitudinal median axis of the said composite filaments, the said crimp being activated or accentuated, if necessary, by an asymmetry of the geometry of the configuration of the cross section of said composite filaments. Tablecloth according to any one of claims 1 to 13, characterized in that the composite filaments have a latent crimp which is activated by heat, mechanical or chemical treatment before the formation of the nonwoven web. Tablecloth according to any one of claims 14 to 16, characterized in that the crimp is accentuated by a thermal or chemical treatment complementary to the consolidated or unconsolidated sheet. Tablecloth according to any one of Claims 1 to 17, characterized in that the elementary filaments are strongly entangled, during or after the division of the composite filaments, by mechanical means acting mainly in a direction perpendicular to the plane of the sheet. Tablecloth according to any one of claims 1 to 18, characterized in that the composite filaments are obtained by electrostatic, mechanical and / or pneumatic deflection and projection onto an endless moving belt and are mechanically entangled by needling or by the action of jets of pressurized fluid, whether or not loaded with solid microparticles, optionally after calendering by points. Tablecloth according to any one of claims 1 to 19, characterized in that it is composed of several superimposed nonwoven layers. Tablecloth according to claim 20, characterized in that each layer consists of filaments from a single die. Tablecloth according to claim 20, characterized in that at least one layer consists of filaments originating from at least two separate dies, said filaments being mixed during the stretching phase, before lapping. Tablecloth according to any one of claims 20 to 22, characterized in that at least one of the layers constituting said ply is formed by means of filaments different from those of at least another of said constituent layers. Tablecloth according to any one of claims 1 to 23, characterized in that the elementary filaments are bonded together by thermofusion of one or more of them formed of a polymer material with a lower melting point , by calendering by means of smooth or engraved heated rollers, by passage through a hot air tunnel oven, by passage over a perforated hot air drum passing through and / or by application of a binding agent contained in a dispersion, in a solution or in powder form. Tablecloth according to any one of claims 1 to 23, characterized in that its structure is consolidated by a chemical or thermal treatment resulting in a controlled shrinkage of a less part of the elementary filaments resulting in a retraction of the web in the direction of its width and / or its length. Tablecloth according to any one of claims 1 to 25, characterized in that it is subjected, after consolidation, to a binding or finishing treatment of the chemical type, such as an anti-pilling, hydrophylizing, anti-treatment. static, improving fire resistance and / or modifying the touch or the luster, of the mechanical type, such as scraping, sanforizing, emery or passing through a trumbler, and / or of the type modifying the exterior appearance such as dyeing or printing. Use of a nonwoven web according to any one of claims 1 to 26 as an apparent component of the interior covering elements of motor vehicles. Use of a nonwoven sheet according to any one of claims 1 to 26 as a textile for interior and exterior furnishings. Use of a nonwoven ply according to any one of claims 1 to 26, as a textile for the manufacture of lining tops and interlayer of shoe components and for the manufacture of the external parts and of the luggage and luggage linings. bags. Use of a nonwoven web according to any one of claims 1 to 26 as a textile for the manufacture of pieces of clothing or linings of pieces of clothing. Use of a nonwoven sheet according to any one of claims 1 to 26 as a textile for the manufacture of household and industrial cleaning cloths. Use of a nonwoven web according to any one of claims 1 to 26 as a substrate for the production of filters or filtering membranes. Use of a nonwoven sheet according to any one of claims 1 to 26 for the production of synthetic leathers.

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