SU1015013A1 - Method of producing non-woven material from polymer melts - Google Patents

Abstract

1. A method for producing a non-woven material from polymer melts, in which polymer is extruded through a die, cools the resulting polymer melt jets with a gas-liquid medium, stretches the threads with a stream of compressed air and places it on the receiving surface, so that it is the fact that, in order to improve the physicomechanical properties of the material and expand the range, when pulling the threads, the stream of compressed air is supplied with a pulsating pressure, the amplitude of oscillation of which is chosen in the range of 0.001-0.5 of its original size The frequency of the oscillation is 0.1-1000 cycles / s. 2. A method of producing according to claim 1, characterized in that when cooling the melt jets with a gas-liquid medium, the ratio of the gas-liquid medium feed rate to the rate of melt flow from the die is extruded between 10 and 200. 3. Method Pop.1, t t i l and when the cooling of the melt jets, the gas-liquid medium j is fed by an even number of oncoming flows with angles one to the other in a vertical plane within 30-90, with pairs of opposing flows arranged in mutually intersecting planes silt and in the same plane.

Description

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The invention relates to the chemical industry, in particular, to methods for producing nonwoven material from polymer melts by aerodynamic molding, and can be used in the preparation of nonwoven material for road, sound insulation and thermal insulation coatings, soft lightweight roofing, and clothing items. Moreover, the fibers forming the canvas have an increased strength and a profiled or hollow section.

A known method for producing a nonwoven material from polymer melts in which the polymer is extruded through a spinneret, the resulting jets of polymer melt are cooled with a gas-liquid medium, drawn out of nit with a stream of compressed air and placed into canvas on the receiving surface C1. . The disadvantage of this method is. is that the maximum cooling rate of polymer melt jets is achieved using a cooling medium having a freezing temperature, and this necessitates the use of a special refrigeration unit, which greatly increases the cost of the whole process, and also its range is limited.

The purpose of the invention is to improve the physicomechanical properties of the nonwoven material, expanding its range by the possibility of obtaining from profiled and hollow filaments.

The goal is achieved by the method of obtaining nonwoven material from polymer melts, in which the polymer is extruded through a die, and the resulting polymer melt jets are cooled with a gas-liquid medium; The filaments are pulled with a stream of compressed air and placed into the canvas on the receiving surface. When the filaments are pulled, the stream of compressed air is supplied with a pulsar to a pressure, the oscillation amplitude of which is chosen in the range of 0.001 to 0.5 of its original value, at a frequency of 0, 1-1000 cycles / s

When the melt jets are cooled with a gas-liquid medium, the ratio of the gas-liquid medium feed rate to the melt flow rate from the filler when extruded is in the range of 10-200.

When the melt jets are cooled, the gas-liquid medium is supplied by an even number of opposing streams at an angle of one relative to the other in a vertical plane within 3090 °, with pairs of opposing streams being placed in mutually intersecting planes. or in one

plane.

FIG. 1 shows the device, a general view; in fig. 2 - section A-A. in fig. one.

From the screw melter 1 through the spinneret 2, which can have 5 round and shaped holes, the fiber-forming polymer is squeezed out as jets of the melt 3 into a gas-liquid distribution shaft 4, where the jets of the melt 3 are exposed to the cooling fluid 5 of a finely dispersed liquid (water, freons, etc.), having a temperature of 7-14 ° C, in air t or gas, for example, in nitrogen, 6 aerosols given from the generator are an even number of opposite flows, not less than two, at angles in the vertical plane refer flax, each other within 30-90, with counter flows 5 being t0: s both in mutually intersecting planes and in one plane (indicated by dashed lines) - The ratio of the feed rate of the cooling gas-liquid medium to the rate of outflow of the melt polymer from the die 2 set in the range of 10-200. The values of the ratios of the indicated velocities are determined from their absolute values: the rate of melt flow of the polymer from the spinnerels, as a rule, is 0.055 m / s. Counter streams 5 are fed from aerosol generator 6. The feed rate of the cooling dispersed liquid is 10-50 m / s. Then the melt 3 jets enter the blowing device 7, while air is supplied to it with a pulsating pressure and a correspondingly varying speed, with an oscillation amplitude ranging from 0.001 to 0.5 of the initial value of pressure and speed, with an oscillation frequency of 0, 1-1000 cycles / s, whereby a pulsating change in the velocity of the compressed air from the blowing device 7 is set to be within 250-600 m / s (the working range of the velocity of the release of compressed air from the gap of the blowing device to the aerodynamic method is molded nonwoven ;. In the blow device 7 under the action of compressed air the filament 8 is deconstructed into the canvas surface 9 on May 10 receiving device 11.

The laboratory test showed that the supply of an even number of gas-liquid flows 5, at least two, at angles relative to each other in a vertical plane within the limits, the ratio of the flow rate of the cooling gas-liquid medium to the flow rate of the polymer melt from the spinneret 2,

5 set in the range of 10–200, the pressure pulsation and, accordingly, the compressed air velocity in the blast of a BOM device 7 with an amplitude of oscillation of -0.001-0.5 at a oscillation frequency of 0.1-1000 cycles / s create turbulent eddies in the gas-liquid distribution shaft 4, cause vibration of the melt jets 3, leading to the occurrence of turbulent vortices on their surface, i.e. the breakdown of the laminar flow around the melt jets 3 by gas-liquid flows 5. This provides a significant increase in the heat transfer coefficient, and therefore an increase in the cooling rate. If the supply of an even number of gas-liquid opposing streams 5 is carried out under the ANGLE of less than 30 °, the vibrations of the melt 3 and the turbulization of the gas-liquid medium are not necessary, since the amount of transverse air flow is insignificant. If the flow of the threads 5 is carried out at an angle of more than 90, then the fiber wrap mode approaches clean cross-flow, which at high rates of supply of the gas-liquid medium causes the melt jets 3 to break, i.e. leads to an unstable molding If the ratio of the gas-to-liquid feed rate the medium to the melt flow rate of the polymer is less than 10 then the turbulent flow around the formeiFlx jets of the melt 3 is not provided by the cooling dispersed liquid (RC). a stable mode of spinning the fibers into a nonwoven material, as the intensity of the melt jets increases dramatically. If the amplitude of pressure oscillations of the compressed air supplied to the blowing device is less than 0.001, the observed vibration does not cause a laminar boundary layer of the cooling medium. If the amplitude of pressure fluctuations is greater than 0.5, a melt 3 breakage and a discharge from the blower device 7 is sufficient, and the boiling frequency is less than 0.1 cycle / s, an increase in the intensity of heat exchange due to an increase in turbulence is not ensured, and the oscillation frequency more than 1000 cycles / s does not provide further sufficiently large higher heat transfer coefficient. The proposed method is illustrated by the following examples, Example 1. Polypropylene with a temperature at the exit of the die 2 270-280 in the form of melt jets 3 in a gas-liquid distribution shaft 4, where melts are melted exposed to the cooling effect of the streams 5 of finely dispersed water in the air, which has a temperature supplied from the aerosol generator 6 by two pairs of opposing streams in a vertical plane at an angle relative to each other 30. Soon The flow of polypropylene melt is set to 5 m / s, and the feed rate of dispersed water in air is 50 m / s, which corresponds to their ratio to 10. Then the melt jets 3 fall into the blowing device 7, where under the action of compressed air supplied with a pulsating pressure 4 4, 004 atm (which corresponds to an oscillation width of 0.001) at a frequency of 0.1 cycle / s, with a pulsating speed of air escaping from the gap in the range of 300-310 m / s, stretched into the thread 8 and unfold on the surface 10 in canvas 9 receiving device 11 .. Characteristics obtained a nonwoven fabric is shown in Table. Example 2. From the tiraeKOBoro melter 1 through the die plate 2, which has round-shaped holes, as-,. Polypropylene sprays with an exit temperature from the die 2 270-280 ° C, in the form of melt jets 3 into the gas-liquid distribution shaft 4, where the melt jets 3 are subjected to the cooling effect of the streams 5 of finely dispersed in air water having a temperature supplied from the generator b aerosols with two pairs of opposite flows in a vertical plane at an angle of 45 relative to each other 45.:The melt flow rate of polypropylene is set at 0.2 m / s, and the feed rate of water dispersed in air of 20 m / s corresponds to a ratio of 10 0. Then the melt jets 3 enter the blower device 7, where, under the action of compressed air supplied with a pulsing & pressure 4-4.4 atm (. Which corresponds to a oscillation range of 0.1), at a frequency of 10 cycles / s, the pulsating speed of air out of the gap within the ZOO-ZZO m / s, stretched in yarn 8 and laid out in canvas 9 and 10 of the receiving device 11. Characteristics of the obtained woven material are shown in the table. Example From the melter melter 1 through the die plate 2, having openings of round forks, polypropylene is extruded with the temperature at the outlet of the die plate 2 2.70-280 С, in the form. of the melt-melt 3 into the gas-liquid distribution shaft 4, where the melt jets 3 are subjected to cooling to the action of the flows .5 finely dispersed / heated in air water having

the temperature supplied from the aerosol generator 6 by two pairs of oncoming flows in a vertical plane at an angle relative to each other, the flow rate. the polypropylene melt is set to 0.05 m / s, and the feed rate of water dispersible in air is 10 m / s, which corresponds to a ratio of 200. Then the melt 3 streams enter the blowing device 7, where, under the action of compressed air, supplied g / pulsating pressure 4-6 atm (which corresponds to an oscillation amplitude of 0.5; at a frequency of 1000 cycles / s, with a pulsating velocity of air escaping from the gap within 300-360 M / q, stretched into filament 8 and laid out in canvas 9 on surface 10 receiving device 11.

Characteristics of the obtained non-woven material in the table.

Fiber strength g

The diameter of a single fiber, microns

Single fiber birefringence index, 10-material elongation,%

Material strength, kgf / mm

Example 4. From the screw of the melter 1 through the die plate 2, having spiral-shaped holes, squeeze out polypropylene with the outlet temperature of the die 2 27028 ° C, / in the form of melt jets 3 into the gas-distributing distribution 4, where the melt jets 3 are subjected to cooling streams 5 finely dispersed in, in-breath of water having a temperature iic, supplied from the generator 6 aerosols to two pargyls of opposite flows in a vertical plane, at an angle relative to each other 45 °. The melt flow rate of polypropylene is set to 0.2 m / s, and the feed rate of water dispersed in air is 20 m / s, which corresponds to a ratio of 100. Then the melt jets 3 fall into the blowing device 7, where under the action of compressed air supplied with a pulsating pressure 4 -4.4 atm (which corresponds to an oscillation amplitude of 0.1), at an air pressure frequency of 10 cycles / s with a pulsating velocity of air escaping from the gap in the range of 300-330 m / s, stretched into thread 8 and laid out in canvas 9 on the surface 10 of the receiving device 11.

one

3-4 4.5

5-6

15

20-30 300 150-200

0.4-0.5

2

 A lightweight non-woven fabric is obtained, since the fibers constituting the canvas have a hollow structure. The specific weight of the obtained material is 25% less than the existing one and is 30 g / m.

Example 5. Polycaproamide with outlet temperature 2 240260 s is extruded from a screw melter 1 through a die plate 2, having round shaped holes, in the form of jets of melt 3 into a gas-liquid distribution shaft 4, where the streams of melt 3 are subjected to the cooling effect of threads 5 finely water dispersed in air having a temperature supplied from an aerosol generator by two pairs of opposing flows in a vertical plane at an angle

relative to each other 45. The melt flow rate of polycaproamide is set at 0.2 m / s, and the feed rate of water dispersed in air is 20 m / s, which corresponds to a ratio of 100. Then the jet

the melt 3 enters the blower device 7, where under the action of compressed air supplied with a pulsating pressure of 4-4.4 atm (which corresponds to the amplitude of oscillation O, 1

with a frequency of 10 cycles / s with pulsiru-,

The velocity of air escaping from the gap in the range of 300-330 m / s is drawn in the yarn 8 and laid out into the canvas 9 on the surface 10 of the receiving device 11.

A nonwoven material having a strength of 0.6 kgf / mm is obtained.

Example 6. Polyethylene terephthalate is extruded from a screw melter 1 through a die plate 2 having round-shaped holes with a temperature at the outlet of the die 2 280-300 ° C, in the form of melt jets 3 into a gas-liquid shaft 4 where the melt jets 3 are subjected to the cooling effect of streams 5 finely dispersed in air water having a temperature of 12 ° C, supplied from an aerosol generator b by two pairs of counter flows in a vertical plane at an angle relative to each other 45 °. The melt flow rate of polytere ntereft alata is set at .0.2 m / s, and the feed rate of water dispersed in air is 20 m / s, which corresponds to a ratio of 100. Then the jets of melt 3 fall into the blowing device 7, where the action of compressed air supplied with a pulsating pressure of 44, 4 atm (which corresponds to an oscillation amplitude of 0.17, at an air pressure oscillation frequency of 10 cycles with a pulsating velocity of vodokha out of the gap within 300300 m / s, stretched into string 8 and expanded into canvas 9 on the surface 10 of the receiving device Events 11.

A nonwoven material having a strength of 0.4 is obtained.

Example 7. From a screw melter 1 through a die plate 2, having round-shaped holes, you-; polypropylene is pressed with a temperature at the exit of the spinneret 2 270280 ° C, in the form of melt jets 3 into the gas-liquid distribution shaft 4, where the melt jets 3 are subjected to the cooling effect of finely dispersed in air water having a temperature of 12 s, supplied from the aerosol generator 6, which creates gas-liquid distribution mine 4 sustainable mist clouds. Melt jets 3 are coated with particles of water and in this state they are blown into the blowing device.

7, where, under the action of compressed air supplied with a constant pressure of 4 atm, they are drawn into the filament 8. Here, too, evaporation of water droplets from the surface of the filaments occurs and the cooling process is completed. Next, the threads are laid out in canvas 9 on the surface 10 of the receiving device 11.

Characteristics of the obtained non-woven material in the table.

25

According to the proposed method, a nonwoven fabric was successfully passed at the pilot plant of VNIISV and tested for strength indicators in a materials science laboratory. The test results are given in the table. As can be seen from the table, the new non-woven material, by comparison with the material obtained by the prototype, has higher physical and mechanical indicators. In addition, lightweight nonwoven fabric samples have been obtained by forming a hollow fiber web, with a 25% reduction in specific gravity.

Claims (3)

1. METHOD FOR PRODUCING NON-WOVEN MATERIAL FROM POLYMER MELTS, in which the polymer is extruded through a die, cool the resulting polymer melt jets with a gas-liquid medium, stretch the filaments with a stream of compressed air and lay them on a canvas on a receiving surface, ** 0 t on it, that, in order to increase the physicomechanical properties of the material and expand the assortment, when the threads are pulled, the compressed air flow is supplied with pulsating pressure, the amplitude of which is chosen in the range of 0.001-0.5 of its initial value , Yri vibration frequency 0.1-1000 cycles / sec. 2. The method of production according to π. 1, characterized in that when cooling the melt jets with a gas-liquid medium, the ratio of the gas-liquid medium feed rate to the melt flow rate from the die during extrusion is selected in the range of .10 - 200. 3. The method of pop. 1, distinguished by the fact that when the melt jets are cooled, the gas-liquid medium is supplied with an even number of counter flows at an angle with respect to one another in a vertical plane within the ZO-ESR, and pairs of counter flows located in mutually intersecting planes or in one plane.