CS205491B1 - Method of and apparatus for manufacturing fibrous webs - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a process for the direct production of a fiber web of oriented fibers of thermoplastic polymers under a spinning die, or a mixture in which fibers emanating from spinning hubs are retained in longitudinal ejectors and deposited on a continuous conveyor belt. either mechanically, thermally or chemically.

Pneumatic methods for preparing fibrous structures by means of ejectors under the spinneret are known which use polymers having low flow properties, i.e., low flow properties. with a flow index of 2.5 to 15 g / 10 min, but at which a high pressure of the gaseous medium in the ejector range of 1.0 to 3.0 MPa is required for sufficient fiber orientation, as taught in U.S. Pat. However, due to the high pressures of the gaseous medium, they require a 10 to 15 m long fiber path, which is very demanding in terms of location of production, energy costs and high noise levels in the working environment.

Further, processes for the preparation of fiber formations under a spinneret using the ejector principle of fiber drawing, e.g. U.S. Pat. No. 3,338,394. in which each fiber strand is associated from two or more fiberized hubs and directed directly to the downstream ejector through the mating and charging elements for the purpose of bundling the fibers and the electrostatic charge.

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All of these techniques use fiber charging from a high voltage source, which presents cost and operational safety problems. These processes also require the ejectors to be placed at the same potential as the fibers in order to prevent the fibers from trapping on the walls of the ejectors, as is the case with the English Patent 914,714.

Another disadvantage of the principle of using electrostatic charging of fibers is that the starting material must have certain electrical properties, but this is often not predetermined even in many important advantageous materials, such as e.g. polypropylene and polyethylene terephthalate. For these materials, it is then necessary to change the electrical properties of the various additives. Thus, U.S. Pat. No. 932,482 discloses the treatment of polyethylene terephthalate and polypropylene after modification in order to reduce the resistivity to below Oh Ohm.cm. Modifications to this patent are made by the introduction of $ 2 by weight of a sulfonated comonomer such as a sulfoisophthalic acid ester.

There are also known processes for preparing fiber formations without additional charging of the fibers by electrostatic charge, which use disintegrating extensions to separate the fibers and deposit them on a mat. These principles are disclosed in German Patent Specification 1 936 354 and U.S. Patent 3,713,590. However, these extensions require special construction and do not allow for sufficient variability in the formation of the fiber formation.

It is also known to provide a suction chamber under a storage device according to U.S. Pat. No. 3,394,435 so as to gradually reduce the suction air in the direction of travel of the conveyor belt. This requirement is realized in such a way that the entire suction is divided into a plurality of suction hoods with separate fans. Spdsob other speed-reducing suction is carried vzduohu pomooou odsávaoej of the chamber are captured directly under umieatnenej Apparatus and by the chamber, wherein the suction vzduohu rýohloet ¹ in the direction of the strip is reduced by increasing the thickness of the layer of badly permeable material. This method is also disclosed in U.S. Pat. No. 3,394,435. These processes are demanding in terms of equipment design, control technology, energy consumption, investment and production costs.

German Patent 1 635 495 discloses a spdsbb for the manufacture of synthetic fiber webs in which a complicated device is used to deposit the fibers on a conveyor belt and to reciprocate. This process has the disadvantage that perfect isotropy in the fiber orientation in the web is not achieved.

Also, U.S. Pat. No. 1,294,680, which describes a method of manufacturing a nonwoven fabric in which a movable deflector is used to deposit fibers on a conveyor belt, does not guarantee the desired uniformity of the physico-chemical properties of the fibrous formation in all directions.

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English Patent 1 315 382 and 1 125 149 disclose methods for making nonwoven fabrics in which the fibers are hot-drawn by either hot air or steam. These processes have the disadvantage that in this way it is not possible to achieve perfect fiber yield in the web and also in increased energy consumption for carrying out the process.

Further, methods of meohanlocal consolidation of fibrous materials are known which are carried out using a combination of pre-ironing and ironing machines, which is very demanding in terms of construction and machine investment costs. The use of a combination of pre-punching and flanging machines has required the requirement to eliminate the stiffness arising in the fiber formation during the meohanioc consolidation β using only a needling machine.

The above-mentioned disadvantages and disadvantages are eliminated by the method of direct production of the oriented fiber structure of oriented fibers of thermoplastic polymers or of a blend under the fiberized hub according to the invention, in which a thermoplastic polymer extruder preferably of polyolefins 10 min, for special purposes up to 90 g / 10 min, optionally from polyamide 6 having a relative viscosity of 2.2 to 2.6, which is then transported in an amount of 0.5 to 2.5 g / min. an orifice in the spinnerets in which the orifices are arranged in two or more groups, preferably two to Styroohs, separated from each other by gaps for easy guidance of the fibers into the individual ejectors. The thermoplastic fibers formed in the spinneret are passed in the form of dies or multi-currents through the shafts where they have been cooled and lead to the ejectors. In terms of shafts, the fibers are intensively cooled so as to avoid sticking in the ejectors.

The high melt flow index in the fiberising hubs achieved by the use of a high degradable thermoplastic polymer with thermal melt degradation during transport to the spinning hubs and a short distance between the spinning hubs and long air ejectors of 3 to 6 m, 4 to 1.0 MPa sufficient fiber orientation in terms of strength 2 to 4 oN / dtex and birefringence 20 to 25.10 ** ® as well as ductility 120 to 200 # for polyolefins and strength 2.5 to 5 oN / dtex, birefringence 30 to 38.10 * * ® and 100 to 150 for polyamides. This relatively high fiber orientation at a greatly reduced pressure of the gaseous medium in the ejector is made possible by the high mobility of the individual macromolecules, which is achieved by using said types of polymers and spinning parameters. This makes the process less space-intensive, e.g. it does not require high construction and investment costs, it is not demanding on energy consumption and it reduces the noise level of operation to a very low level.

Prior to entering the ejectors, a portion of the fiber yarn or a plurality of yarns passes along the ski area to wash the rolls and touch the surface of the rolls. The function of these rollers is to control the speed of movement of a portion of the fibers or the close proximity of the fibers, thereby achieving a different wound structure, for example straight fiber sections, curled fibers, varying degrees of orientation.

205 491 fibers in the hooking of the parameters and the storage of the parameters, without the fibers being caught on these or other parts of the machine, i.e. in the ejector or between the storage rolls.

The fibers elongated in the ejector pass through the slot between the two roll bearings with an axis inclined from 0 ° to 80 ° relative to the axis of the storage belt without contacting. Come. two or more pairs of support rollers are disposed at each spinning hub, the axes of these pairs of cylinders being at an angle of from 0 ° to 16 ° to each other, thereby obtaining a flat fiber structure with vigorous anisotropy of the physical-meo-healing properties. Preferably, this angle of 90 ° is used to achieve the physical-meohanical properties ratio of the sheet fiber formation Is1. A long ejector is disposed above each double-stacked roller, the individual ejectors below each spinning hub being offset relative to each other in a direction perpendicular to the conveyor belt by 100 to 450mm. This alignment permits layering and cross-linking of the individual fiber ribbons as well as providing the weakened edges necessary to bond the fibers from the next spinneret. The air consumption per ejector is in the range of 30 to 35 kg / h per 5.2 to 6 kg / kg womb, which is a further advantage of the proposed process over the known procedures of the aforementioned patent specifications.

The fibers after exit from the storage rolls are deposited in the form of cross-layers on the storage conveyor belt, where they are held by creating a vacuum of air at the point of formation of the fibrous formation at the exhaust slot, thereby preventing . Low air pressure in debt. The ejector and the pulverizer allow the use of a single extractor slot, which is highly advantageous in terms of simplicity of the machine and energy saving compared to previously known processes.

The fiber impact area on the conveyor belt above the aspiration slot is closed from all sides by protective donors forming a fleece chamber preventing the secondary air from being drawn in from the surrounding space and eliminating its adverse effects on the deposited fibers. At the point of impact of the fibers on the conveyor belt, a fabric softener is simultaneously applied to the flat fibrous structure to improve the process of meohanioccanning. On the conveyor belt, the fiber structure may be pre-expanded - compacted by the pressure roll or lead directly to the needling and possibly other reinforced thermal or flame-retardant ·

The needling is carried out in a needle machine of conventional construction, which is preceded by a feed of a very special construction, which transports the fiber formation to the flight machine and limits the passage of the fiber formation. The use of these rolls makes it possible to omit a pre-ironing machine from the line assembly without compromising the quality of the final product. This saves energy and investment costs of construction and machinery.

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In the needling process, the fiber structure is mechanically fixed, in particular in the vertical direction. Strengthening is dependent on multiple factors, of which the most significant are the number of injections / s ² , lag, depth of injection, type and number of needles and so on. In the method of needling the filament formation with continuous filaments, a greater insertion depth of 15 to 19 mm and a lower number of spikes of 40 to 80 are advantageously utilized compared to the known consolidation of the staple fiber formation, thereby extending the service life? the needles and the needle needles machine because the machine flows at a substantially lower speed.

With the above-mentioned nonwoven and meohi-amide bond strength parameters e, the web strengths reach 500 to 1000 N / 5 µm and ductility 80 to 150 $ depending on the basis weight of the web. These properties are at the level respectively. exceed the characteristics of similar products manufactured under fiberised hubia abroad and make it possible to use these nonwovens as geotextiles for road and railroad exhibitions in unbearable terrains, where they act as soil filters, water works, amelioration works and the like.

The thermal consolidation of the fiber formation is carried out by thermo-fusion of the cell with hot air or steam between the screen and the perforated drum or pair of screens or between the rolls of the calender which may be tread pattern or non-pattern. In the case of thermal bonding, bonding occurs between the fibers, thereby reducing the thickness of the fiber formation, increasing strength and reducing ductility. The best properties of the fibrous formation after thermal consolidation are achieved by using a fibrous formation comprising fibers with a different degree of orientation. It is about improving the feel, reducing stiffness while increasing physico-mechanical values of the product. In this way, reinforced materials are used for the production of asphalt roofing and the like.

The chemical reinforcement of the fiber formation is used in order to achieve the special properties of the materials used for certain applications. It is carried out by depositing a chemical binder on the fibrous formation of cells by spraying or dipping and squeezing. The applied chemical binder is condensed on a fiber formation by drying in an oven. Chemical bonding improves the uniformity of the fiber formation, the feel, the adhesion to the coating materials and the stiffness. The use of fireproof reinforced webs is, inter alia, as a backing for PVC leatherette, etc.

The device for the direct production of a sheet fiber structure according to the invention consists of at least one melting extruder, a distribution branch with spinning blocks, behind which smoothing shafts are provided, the air ejectors are extended and the transporter is stored. Between the cooling shaft and the drawing air ejectors spaced from the spinneret 3000 to 6000 mm for at least one fiber stream, a braking cylinder is provided, which extends through its periphery to the fiber flow passage between the spinning hub and the air-drawn ejectors. Under the air ejector, there are two double parallel cylinders with a spacing of 3 to 12 mm. The common axis imposes an angle of 0 ° to 80 ° along the axis of the storage conveyor belt. The dual loaders oscillate in a horizontal plane in a direction perpendicular to the longitudinal axis of the load conveyor belt at a frequency of 2 to 12 Hz and the Ioh swivel size is adjustable during the machine run from 1 to 12 mm. Below the pair of rollers there is a fleece chamber, extending to the transfer conveyor belt, below which is the aperture of the suction device.

The conveyor belt is followed by a needle machine with feed rollers.

FIG. 1 shows a schematic view of a planar fiber formation apparatus, FIGS. 2a-2d schematically illustrate the possibilities of conducting a fiber stream after braking, FIGS. 3a-3o illustrate the arrangement possibilities. ukladaoíoh valoov.

In FIG. 1 is a schematic view of an apparatus according to the invention, which consists of a group spinning hub 1 which is connected to an extruder (not shown) by means of a melt metering pump of a thermoplastic polymer. Zvláknovaoia hubioa 1 is adapted to create dvooh vlákennýoh streams 2. The zvlákňovaoou hubioou 1 is located ohladiaoa ěaohta 2 and below it at a distance of 3000-6000 mm from the surface of this zvlákňovaoej hubioe 1 is located a few ejector £ ^e inlet pressure vzduohu. Between the pair of ejectors 6 ^{and the} shaft 2 are placed bviao 2. Under the detectors 6 at a distance of 1 to 80 mm, for each fiber stream 2, two cylinders 6 are formed which oscillate in the horizontal plane in a range less than the distance between the two cylinders 6. frequency 2 to 12 Hz. The axis of the rollers 6 is deflected from the axis of the lowered feeder belt 8 by an angle of 0 ° to 80 °. Above are captured conveyor belt _8 is pomooou zvislýoh orifice plates formed rúnotvomá chamber 2 »L ° ^f which is the lower suction 2 vzduohu from above the conveyor belt _8 · Y direction of movement of the conveyor belt 8 and the fibrous formation 14 thereon is formed in the unit is included to application 10 fabric conditioners or other The needle machine 13 is provided with a pair of rollers 12 in front of the needle assembly (not shown). .

In FIG. Figures 2a, 2b, 2o, 2d show some examples of filament flow lines 2 along roller brakes 4 to the ejectors. Fig. 2a shows filament flow lines 2 along a single roller 4, while in fig. one brake cylinder 4 and the other part is not braked. In FIG. 2o, a pair of roller brakes 4 is used for one fiber stream 2, while in FIG. 2d, a combination of guiding one portion of the fiber stream 2 after a pair of brake rollers 4 is used, while the other portion of the fiber stream 6 passes directly to the ejector

In FIG. 3a, 3b, 3o show the relative positioning of the pairs of roller supports 6 on the carrier 16 in a horizontal plane. Fig. 3a shows two roller supports 65 with roller axes inclined at 90 ° to each other, while in Figs. 3b is similar to the illustrated location of the four pairs of roller supports 6 on a common carrier 16 at an angle of 0 ° and 160 °, and in FIG. 3c shows the mounting of four pairs of roller bearings 6 at an angle of 90 ° on a common support 16.

Example 1

By means of the device corresponding to FIG. 1, provided with a group spinning hub. Two groups of spinning orifices are fed from the extruder (not shown) through a batch pump of a polymer-polypropylene melt having a flow index of 50 g / 10 min in an amount of 180 g / min, i.e. 1.28 g / min. Two fiber streams containing 70 individual fibers are formed in the spinneret, passing through the shaft in which it has been cooled to 60 ° C. Each of the fiber streams enters a separate elongated air ejector via a brake cylinder, the distance between the spinning hub and the long air ejector is 5000 mm. In the long air ejector, the fibers are elongated by compressed air at a pressure of 0.8 MPa to obtain a fineness of 3000 m / min. The air consumption is 35 kg / h per ejector, which corresponds to an air consumption of 6 kg / kg fleece. After elongation, the individual fibers have a strength of 3.1 µN / dtex, an elongation of 180 µm and a birefringence of 24.5 x 10 6. Every wick *. the kennel current enters after elongation between a pair of support rollers which are 25 mm apart from the long air ejector and oscillate in a horizontal plane at a frequency of 8 Hz and with an oscillation of 8 mm. The axis of the support rollers is inclined by 45 ° relative to the axis of the support conveyor belt, the angle between the axes of the two pairs of support rollers being 90 °. The fibrous stream is diverted from the original direction by a transition between a pair of storage rolls and is deposited in the form of a crossbeam on a storage conveyor which is spaced from the axis of the storage rolls 700 mm. This creates a planar fiber formation, which is softened with a suitable fabric softener and enters the needling machine through two rollers, where it is mechanically consolidated with 60 stitches / cm ² , thereby obtaining the required parameters, ie basis weight *

300 to 600 g / m ² , strength 500 to 1000 N / 5 cm and ductility 80 to 150 µl depending on basis weight. The finished planar fiber formation is rolled into the winding of the finished product, which is used as a geotextile in road construction, after cutting the edges.

Example 2

The fiber web, similar to Example 1, is formed from a melt of polyamide 6 having a relative viscosity of 2.4 and a moisture content of 0.07 µm, or a mixture of polyamide 6 and mixed polyamide consisting of a mixture of caprolactam, hexamethylenediamine, adipic acid and sebacic acid using? spinneret with four groups of spinnerets at a dosage of 0.7 g / min. In the spinning hub group, four filament streams are formed, which are fed into four ejectors, one of each pair of filament streams being fed directly to the ejector and one by frictional contact over the wedges of the two braking cylinders. The distance of the ejectors from the surface of the spinneret is 3200 mm;

205 491 fibers are ejected in the ejectors at a speed of 1600 m / min. They achieve a strength of 4 cN / dtex, a strain of 140% and a birefringence of 35.10. Air consumption is 30 kg / h per ejector, which corresponds to an air consumption of 5.2 kg / kg mine. Each filament stream flows from the ejectors between a pair of storage cylinders 5 mm away from the ejector, these cylinders oscillating horizontally at a frequency of 3 Hz and an oscillation of 11 mm. In two pairs of storage rollers, they are inclined by 75 ° relative to the axis of the storage conveyor belt *, while the axes of the other two storage roller pairs are parallel to the axis of the conveyor belt *. The fiber streams are deposited on a conveyor belt spaced 600 mm from the roller axes, using four-foot roller pairs to achieve better fiber cross-over and better flattening 2 ^{in the} 100 to 200 g / m product, which after refining in a thermally strengthened device, it has use as a backing layer for the production of roofing, such as table cloths, ironed liner for the garment industry and the like.

Example 3

The sheet fiber structure as in Example 1 is formed from a 20 g / 10 min melt polypropylene melt using a twin-group spinneret having a twin group of spinnerets at a dosage of 2.2 g / min. In the spinning hub, two fiber streams are formed, which are guided through a cooling shaft to the two ejectors of the ejectors, each fiber stream being divided into two parts before entering the ejector, one of which passes along the perimeter of the starter cylinder and the other owing to the ejector »without touching the throat. The elongating ejectors are spaced from the spinning huhioe surface of 5800 mm, the fibers in the ejector being aligned at a fineness of 3500 m / min. Each filament stream comes from an ejector between a pair of cylindrical stacks oscillating at 11 Hz and a 4 mm oscillation spaced from the ejector * 70 mm. The axis of the storage rolls is glass with respect to the axis of the storage conveyor belt by 45 °, the angle between the axes of the double storage rolls being 90 °. The filament streams aa, after passing through the deposit rolls, deposit a tranport belt, which is formed by a fibrous formation transported to mechanical consolidation in a needle machine and subsequently to further refinement in a heat-consolidated device. The formed fiber sheet having a basis weight of 500 to 600 g / m 2 is used as the backing layer for textile flooring.

Claims (2)

9,205,491 OBJECT OF THE INVENTION A method for producing a sheet-like fibrous structure of oriented fibers of thermoplastic polymers, optionally in admixtures, wherein a perforated storage conveyor belt with a lower filament-shaped melt in the form of a fibrous stream is drawn from the at least one spinneret. by suctioning in the fiber depositing medium and strengthening, characterized in that the thermoplastic polymer melt or a mixture of viable polymers with a flow index of 15 to 90 g / 10 min for polypropylene and a viscosity of 2.2 to 2.6 for polyamide 6 , respectively. its mixture with another polyamide in an amount of 0.5 to 2.5 g / min per one spinneret opening in the form of at least two fibrous streams which are heated in the shaft, at least a portion of the solidified fibers being adjacent to frictional contact with the grain of the at least one brake drum and then in the air ejector at a distance of 3000 to 6000 mm of the spinneret, with a compressed air stream drawn to a final fiber velocity of 1500 to 4000 m / min, at a distance of 1 to 80 mm from The ejector traverses the gap between the pair horizontally and oscillates and moves horizontally at a frequency of 2 to 12 Hz and shows the shape of a sheet-like fibrous structure at a distance of 500 to 1000 mm from the rollers. 2, the apparatus for producing a sheet-like fibrous structure according to item 1 comprises at least one forming extruder, a distributing branch with spinning blocks, followed by shaft shafts, extending air ejectors, and a storage conveyor belt characterized in that between the cooling at least one brake cylinder (4) extending from the fiber surface of the fiber stream (2) between the spinning hub and at least one fiber flow (2) is provided by the shaft (3) and the length of the air ejectors (5) spaced from the spinning hub (1/3000 to 6000 mm). (1) and with air duct (5) under which, in a distance of 1 to 80 mm, there is a dual axis parallel storage of the rollers (6) with a pitch of 3 to 12 mm; up to 80 ° and this pair of rollers / 6 / oscillates in a horizontal plane in a direction perpendicular to the axis of the conveyor belt / 8 / sf with the order of 2 to 12 Hz, the magnitude of the amplitude (16) in the range of 1 to 12 mm is adjustable during the running of the machine and below the pair of storage rollers (6) is incorporated a fleece-forming chamber (7) extending to the storage conveyor belt (8) after which the subsequent machine (13) with the feed rollers (12) is provided with an aspiration slot (9) formed by the drawing conveyor belt (8) in the incidence of the incidence of the fibers