KR100825066B1 - Preparation of long staple fiber non-woven fabric and apparatus - Google Patents

Abstract

The present invention provides a method for producing a long-fiber nonwoven fabric by cooling and solidifying after spinning and imparting static electricity to the multifilament drawn by high-pressure air, and then opening it by dropping it on a conveyor belt under suction to form a web and calendering the obtained web. The present invention relates to a method for manufacturing a long-fiber nonwoven fabric and an apparatus for implementing the same, wherein the charged multifilament collides with a plate inclined at a predetermined angle, and an apparatus for implementing the same is provided. It is possible to increase the degree of freedom of the filament to improve the island-dispersibility, so that the MD / CD strength ratio is 2 or less and the distribution is uniform, so that a low weight product of less than 30 g / m 2 can be produced, and more than 30 g / m 2 When producing heavy products, the distribution and machine direction / lateral direction (MD / CD) strength ratio are uniform and high. This makes it possible to provide long fiber nonwovens of high commercial value.

Description

Long fiber nonwoven fabric manufacturing method and apparatus {Preparation of long staple fiber non-woven fabric and apparatus}

1 is a schematic view showing a conventional long fiber nonwoven fabric manufacturing apparatus

FIG. 2 is a schematic enlarged view for explaining the opening means of the device of FIG.

3 is a view for explaining a state in which the rectifying means is installed in the lower opening means according to the present invention;

 * Brief Description of Drawings *

1. Spinning block 2. Cooling chamber

3. High Pressure Air Supply 4. Valve

5. High pressure air ejector 6. High pressure pipe

7. Opening means 8. Net conveyor

9. Suction means 10. Calendar roll

11. Winding means 12. High voltage generator

7a. Ground plate 7b. Charging electrode

7c. Daejeon Front

71. Inclined collision rectifier 72. Vertical guide rectifier

The present invention relates to the production of a nonwoven fabric, and more particularly, to a method and an apparatus for producing a high quality long fiber nonwoven fabric having excellent uniformity.

The spunbond method is well known among the manufacturing techniques of nonwoven fabrics. Figure 1 schematically shows a device for producing a typical spunbond long fiber nonwoven. As shown, the multifilament thread Y radiated from the spinning block 1 is cooled and solidified in the cooling chamber 2 and subsequently drawn in the high-pressure air ejector 5 and then moved to the net conveyor 8. It is stacked in the form of a web (web) on. The laminated web is imparted with heat and pressure simultaneously on the calendar roll 10 to impart a certain thickness and physical properties, and then wound to prepare a spunbond nonwoven fabric.

The long fiber nonwoven fabric produced by the spunbond method is widely used for industrial purposes because it can produce a stronger and thinner product than the general short fiber nonwoven fabric produced by other methods. Typically, the spunbond nonwoven fabric is produced by spinning the filament fibers in the same manner as the conventional synthetic fiber spinning process. That is, since the product of a high strength can be produced more efficiently and simply than the conventional short fiber nonwoven fabric manufacturing method, the production quantity and use of a spunbond nonwoven fabric are expanded further.

However, the spunbond long fiber nonwoven fabric manufacturing method is disadvantageous in producing a low weight product due to poor uniformity than the conventional short fiber nonwoven fabric.

That is, in the conventional short fiber nonwoven fabric manufacturing method, a unique homogenization process for uniformly arranging short fibers having a length of 20 to 100 mm in the longitudinal direction using a card machine is developed, and the uniformity of the nonwoven fabric is generally excellent.

On the other hand, the spunbond method is a method of manufacturing by sprinkling the filaments drawn from the high-pressure air ejector 5 onto the net conveyor that is continuously moved using the opening means 7 as it is, and thus the net conveyor 8 moving with the interference of air. The distribution (evenness) of the nonwoven fabric is affected by the relative speed difference between and and the proper opening of the filament in the opening means 7.

As such, the spunbond method is a method of manufacturing a nonwoven fabric directly in an integrated process without a separate homogenization process such as a conventional short fiber nonwoven fabric manufacturing process, so that the uniformity is inevitably reduced. Particularly, when the low weight nonwoven fabric of 30 g / m 2 or less is produced such a problem, the production of the low weight nonwoven fabric by the spunbond method is practically difficult. In addition, even when producing a heavy product of 30g / ㎡ or more, the distribution is worse than the short fiber nonwoven fabric, so the variation in weight and strength (CV%) is high, causing deterioration and failure of the overall product.

However, the spunbond method is the most widely used nonwoven fabric manufacturing method because of the absolute strength and productivity is high and simple compared to the short fiber nonwoven fabric manufacturing method. In addition, various solutions have been tried, adopted, and developed to solve the above-mentioned distribution defect problem.

For example, U.S. Patent No. 4,009,508 proposes a method for spreading filaments in order to improve the distribution in a spun bond manufacturing apparatus in which a plurality of opening means are arranged. That is, in the method of manufacturing a spun bond in which a plurality of opening means are arranged, a high voltage electrostatic imparting device is installed on the opening means to give the filaments having the same polarity to the filaments traveling at high speed, thereby giving the filaments an electrostatic force. It describes how to make a uniform nonwoven fabric by repulsion. This method is the most effective method for uniformly dispersing filaments and has been applied to many spunbond nonwoven fabric manufacturing apparatus. However, this method requires a great deal of attention in the actual process because the difference in the distribution occurs depending on the arrangement method and size of the opening means and the amount of static electricity. That is, the biggest problem in practical use of this method is that the distribution between the opening means and the opening means cannot be adjusted realistically. Although the opening of the area covered by each opening means is uniformly produced due to the repulsion of the filaments due to the electrostatic charge, the opening of the opening means and the opening means causes filament not to be laminated or too much due to the rebound of the filaments. In general, when a wide sheet is produced, poor distribution occurs in the longitudinal direction of the furrow-like shape in the longitudinal direction.

In order to solve this phenomenon, as in US Pat. No. 4,163,305, a collision plate is installed at the bottom of the opening means, and the collision plate is used to properly separate the filament and the accompanying air flow to open the island, and at the same time oscillation (OSCILLATION) A method of uniformizing the distribution of filaments over the entire width by accompanying movement is presented. The spunbond manufactured in this manner is capable of producing a nonwoven fabric having a uniform shape without a nonuniformity in the longitudinal distribution as in US Pat. No. 4,009,508. However, the spunbond manufactured by this method has the advantage of producing a non-woven fabric of less than 30g / ㎡ with a good distribution, but the filament is arranged in the machine direction (MD) due to the action of the impingement plate, which is an essential device of the present invention . The nonwoven fabric thus prepared has the advantage of good distribution and excellent strength in the MD direction, but the disadvantage of lowering the strength in the transverse direction (CD) is inevitable. Nonwoven fabrics with good physical properties should have a good distribution, and the MD and CD strengths are the same. In general, the short fiber nonwoven fabric has a MD / CD strength ratio of 2 or more, whereas the nonwoven fabric manufactured by the same method as in US Pat. No. 4,163,305 has a MD / CD strength ratio of 3 or more. There is a problem.

In addition, U.S. Patent No. 4,334,340 also discloses impingement plates and airflow diffusion devices for arranging the filaments constituting the nonwoven fabric in the machine direction to produce a spunbond nonwoven fabric having a uniform shape as components of the patent. US Pat. No. 4,833,758 also features a method of arranging the carding means in addition to the impingement plate and oscillation method to produce a uniform spunbond nonwoven fabric. However, this method also cannot avoid the form in which the filaments are arranged in the MD direction, and thus cannot be said to be a spunbond method having a uniform MD / CD strength ratio.

Japanese Patent Publication No. 63-24108 also manufactures a method for producing a uniform spunbond, but is similar to the method described in US Patent Nos. 4,163,305 and 4,883,758. As described above, in the conventional spunbond manufacturing method, the product has a uniform distribution so that a product of less than 30 g / m 2 can not be produced, and even a uniform non-woven fabric having excellent physical properties of MD / CD strength ratio of 2 or less cannot be produced.

Therefore, an object of the present invention is to provide a spunbond long fiber nonwoven fabric having a uniform distribution.

In the study of the present inventors to solve the above problems, the nonwoven fabric is impossible to use the impingement device in order to lower the MD / CD strength ratio, and move the filaments directly in the opening means as in the conventional method US Patent No. 4,009,508 It is possible to obtain a nonwoven product having a low MD / CD strength ratio only by using a method of spraying on a net conveyor.However, the method described above provides excellent distribution and physical properties of the part covered by the carding device, as described above. The distribution of can't be controlled, which makes the area between the opening means a kind of blind spot, so that the filament is distributed less or more, which lowers the overall product quality and finally lowers the value of the product. The blind spot between the islanding means The idea could be reduced, and the search for a way to make it possible led to the development of the method of the present invention. That is, the present invention has been devised by thoroughly examining the reason for the occurrence of blind spots between the opening means in the conventional method and identifying the cause. The present inventors found that the cause of poor distribution occurring between the opening means in the present invention is caused by the electrostatic force generated between the opening means and the interference caused by the excessive amount of air flowed into the lower part of the opening means and the unevenness of the air flow dispersion. They found out.

The same kind of charges imparted to the filaments in the high voltage charging electrode 7c of the conventional opening means 7 as shown in FIG. 2 play a role of repulsing the filaments. This manufactures a nonwoven fabric having a uniform distribution. However, for example, filaments that are opened and advanced in two adjacent opening means move with the same charge and thus repel each other. Therefore, the space between the opening means causes the filaments to be arranged relatively less by the repulsive force of the filaments. Since this phenomenon occurs all in the space between the individual opening means, the uniformity of the product produced as a whole becomes very poor and cannot be sold commercially. In addition, due to the speed of the filament and the air that is drawn and ejected at high speed in the high-pressure pipe 6, adjacent air is drawn into the opening means 7. In the opening means 7, the filaments ejected from the high pressure pipe 6 are rapidly expanded in the opening means 7, and the pressure drops, and at the same time, the filaments are primarily opened. The opening phenomenon in the opening means 7 is interrupted due to the increase in the internal pressure due to the introduction of adjacent air. As a result, the free movement of the filament is limited and the opening width of the opening means is reduced, resulting in poor overall product uniformity. In addition, the amount of air that spreads out to the opening means 7 due to the introduction of excessive air also increases. Surplus air at the bottom of the carding means serves to prevent filament spreading between the carding means. That is, the excess air introduced into the opening means plays a role of hindering the free movement of the filament in the opening means and the lower end, thereby inhibiting the diffusion of the filament. Therefore, the uniformity of the final product is worsened.

The inventors of the present invention carried out the test by covering the top of the opening means 7 to prevent the introduction of the surrounding air in order to improve the adverse effect caused by the excessive air introduction described above. As a result of the test, the amount of surplus air was reduced and the diffusion of filament was slightly increased. This phenomenon is due to the characteristic that the high-pressure charges produced by the charging electrode 7b are activated by the supply of sufficient air and are imparted to the filaments. That is, under the same large voltage, as the amount of air supplied increases, the amount of charge increases, thereby activating the charging of the filament, and consequently, the repulsive force of the filament is increased, thereby increasing the diffusion width. That is, the method of reducing the air intake by making a cover on the top of the opening means 7 was effective in reducing interference by surplus air, but there was a limit in improving the distribution because the charge amount was reduced.

The present inventors developed the apparatus of the present invention as a result of repeated tests to reduce the interference phenomenon at the bottom of the opening means while using the role of surplus air in terms of increasing the amount of charge.

Therefore, according to the present invention, a method of manufacturing a long-fiber nonwoven fabric by forming a web by calendering the multifilament which is solidified after spinning and drawn by high-pressure air, and then is opened by dropping it on a conveyor belt under suction. A method of manufacturing a long fiber nonwoven fabric is provided, wherein the charged multifilament is impinged on an inclined plate at a predetermined angle and then impinges on a vertical plate.

In addition, according to the present invention, a long-fiber nonwoven fabric manufacturing apparatus having a stretching means for stretching the cooling and cooling the multifilament after spinning, high pressure air, the carding means for imparting static electricity to the stretched multifilament to be administered by an air suction vacuum conveyor belt In the lower part of the opening means has a first plate and a first plate extending vertically from the lower end of the inclined rectifying plate and the inclined rectifying plate of the impingement plate at a predetermined distance apart from the first plate having a top higher than the height of the first plate A long fiber nonwoven fabric manufacturing apparatus is provided, characterized in that a rectifying means having a guide rectifying plate serving as a second plate is provided.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings, which illustrate an apparatus for implementing a preferred manufacturing method of the present invention.

The main feature of the present invention is to separate the surplus air from the filament by dropping the charged multifilament in the carding means to impinge on the rectifying plate inclined at a predetermined angle and then to the vertically inclined plate once again to improve the degree of freedom of the filament It is to increase dog island dispersibility.

A preferred example of the device configuration for this is illustrated in FIG. 3.

In the device shown, the upper end of the opening means 7 is designed to increase the amount of charge of the filament, which is used to generate a sufficient amount of charge inside the opening means 7 so that the surrounding surplus air is freely drawn as in the prior art. An inclined collision rectifying plate 71 inclined at a predetermined angle θ in the form of an impingement plate below the opening means 7 and a first plate 72a and a first plate 72a extending vertically from the lower end of the inclined rectifying plate. A vertical guide rectifying plate 72 is installed to face the predetermined distance from the first plate 72a and becomes a second plate 72b having a top higher than the height of the first plate 72a to separate the surplus air from the filament, and to free the filament. Increase the islet dispersibility.

According to the present invention, a spunbond product having a uniform distribution and an MD / CD strength ratio of 2 or less could be easily produced. The inclined collision rectifying plate 71 plays an important role in separating excess flow of air from the filament. The filament and the surplus air passing through the opening means 7 hit the inclined oblique impact rectifying plate 71 at a predetermined angle, so that the filament and the air flow are naturally separated. At this time, the more air involved, the faster the collision speed of the inclined inclined rectifying plate 71, the more filaments are spread in the inclined inclined rectifying plate 71. Excess air flow is also reliably separated from the filament to increase efficiency. In addition, since the amount of charge also increases in the opening means 7, the diffusing force of the filament is doubled, and the distribution degree becomes more uniform.

In the present invention, when only the oblique impact rectifying plate 71 is used, a product having a uniform distribution may be manufactured, but a product having an MD / CD strength ratio of 2 or less cannot be manufactured. That is, when only the inclined collision rectifying plate 71 is used, the filaments collide with the inclined collision rectifying plate 71 and are manufactured to be arranged in the traveling direction of the net conveyor 8. The manufactured product can produce only the MD / CD strength ratio of 3 or more in which the filaments are arranged almost in the machine direction (MD), so that the MD strength is high but the transverse direction (CD) is low.

In the present invention, the first plate 72a and the first plate 72a extending vertically from the lower end of the inclined collision rectifying plate 71 in order to be able to produce a product with uniform distribution and low MD / CD strength ratio (2 or less). A vertical guide rectifying plate 72 is installed to face the predetermined distance from the second plate 72b having an upper end higher than the height of the first plate 72a.

That is, the filaments arranged in the machine direction in the oblique impact rectifying plate 71 collides again in the second plate 72b of the vertical guide rectifying plate 72 and is formed between the first plate 72a and the second plate 72b. It is rearranged laterally through the narrow gap of. The filaments rearranged between the first plate 72a and the second plate 72b are randomly arranged in the machine direction (MD) and the transverse direction (CD), and the interference shape between the opening means is also eliminated. It is possible to produce spunbond products with uniform distribution and MD / CD strength ratio of 2 or less.

In the present invention, the rectifying plate, which is a core device, plays an important role in the installation position, angle, size, and spacing between the rectifying means. The position of the inclined collision rectifying plate 71 is preferably set at a position about 0 to 100 mm away from the lower end of the opening means. If it is installed more than 100mm, the pressure of blown air drops and sufficient separation opening effect does not appear.

The inclination angle θ of the inclined collision rectifying plate 71 also plays an important role in the separation of excess air and the diffusion force of the filament. If the angle θ is too large, excess air and filament will adhere and accumulate, making product production difficult. An appropriate angle θ of the inclined collision rectifying plate 71 is in a range of 20 to 70 degrees. More preferably, it is 30-60 degrees. The total size (length) of each of the rectifying plates 71 and 72 is preferably about 50 to 500 mm. If the length is too short, the filaments are not randomly arranged between the rectifying plates, resulting in uneven distribution and an increase in the MD / CD intensity ratio to 2 or more. In addition, if the length becomes too long, more than 500 mm, the speed of the filament passing through the rectifying plates 71 and 72 falls, causing interference with each other, and the opening state becomes worse. The spunbonded product thus manufactured is not commercially available due to the appearance of spot defects in which filaments are aggregated and scattered at regular intervals of about 20 to 100 mm. Therefore, the lengths of the rectifying plates 71 and 72 must be rearranged again in the transverse direction (MD) while maintaining the speed sufficient to maintain the opening state so that the filaments do not slow down. According to the test results of the present inventors, the length of the rectifying means has to be kept at least 50 mm and at most 500 mm, although it varies slightly depending on the manufacturing conditions. Preferably it is 100-300 mm level. The spacing between the first plate 71a and the second plate 72b is also an important factor in the arrangement of the filaments. The filaments should be spaced at regular intervals in order to be properly randomly arranged and to maintain proper speed.

According to the test results of the present inventors, about 2-50 mm was suitable for the space | interval between the 1st board 71a and the 2nd board 72b. If the gap is 2 mm or less, the filament is attached or blocked on the wall of the rectifying plates 71 and 72 due to the speed decrease due to the friction between the filament and the rectifying means. If the gap is 50 mm or more, the inclined collision rectifying plate 71 The filaments arranged in the machine direction (MD) are not mixed enough in the transverse direction (CD) due to the collision effect of), so that a product with a low MD / CD strength ratio cannot be obtained.

The length that the filament collides with the inclined collision rectifying plate 71 and the frictional running is also an important variable, but usually about 20 to 200 mm is appropriate. The material of the rectifying plate can be used stainless steel, galvanized steel, cast steel, crumdo steel, thermoplastic resin, etc., there is no particular limitation. However, the surface in contact with the filament should be smooth.

Hereinafter, embodiments of the present invention will be described. The effects of the present invention are not limited to the examples.

EXAMPLE

The long fiber nonwoven fabric was manufactured in the apparatus of FIG. 1 provided with the rectifying means of FIG.

First, polyethylene terephthalate having an intrinsic viscosity (IV) of 0.645 was melted and extruded at a spinning temperature of 285 ° C. The number of capillaries used in the detention was 40Hole / Cop and the spinnerets were all 6Cop. The multifilament extruded through the spinneret is cooled and solidified by a cooling air of 19 ° C. × 0.55m / sec. In a 1 m length quench chamber, and then stretched with a conventional air ejector installed at a 1.5 m position in the spinneret and then opened. Introduced to the means (7). The filament introduced to the opening means is charged to the filament Y through ions generated in the form of positive or negative charge through the charging electrode 7b with a high voltage of 20 kV or more generated by the high voltage generator 12. Charged filaments (Y) are sprinkled on a net conveyor (8) running at random after being arranged randomly through the oblique impact rectifying plate 71 and the vertical guide rectifying plate 72 at a high speed of 20 to 120 g / ㎡ Samples were prepared. In this embodiment, the gap between the opening means 7 was kept constant at 65 mm and the discharge amount was 80 g / min · Cop. In the present example, the width of the product manufactured in the test was set constant to 1.0 m, which is the manufacturing width of the manufacturing apparatus. The rectifying plates 71 and 72 were installed at the 5mm position directly below the opening means 2, and the chromium steel was used.

Table 1 shows the long fibers manufactured by varying the angles, lengths, and clearance gaps between the first and second plates 72a and 72b of the inclined collision rectifying plate and the vertical guide rectifying plate. Properties of nonwovens are presented.

[Comparative Example]

The same procedure as in Example 6 was repeated, except that the rectifying plates 71 and 72 were not used.

division Collision Rectifying Plate (71) Gap thickness (mm) Properties Length (mm) Angle (θ) Collision field (mm) weight Distribution Strength (MD) Kg / 5cm Strength (CD) Kg / 5cm MD / CD strength ratio Example 1 150 50 40 5 20 Great 5.5 3.7 1.5 Example 2 150 50 40 10 20 Great 5.9 3.1 1.9 Example 3 150 50 40 30 100 Great 18 11 1.6 Example 4 150 50 40 50 120 Great 22 12 1.8 Example 5 150 30 40 3 30 Great 6.0 4.1 1.5 Example 6 300 45 40 5 30 Great 7.0 5.7 1.9 Comparative Example 1 150 20 40 3 30 Bad 6.5 3.2 2.03

* Distribution Chart: A sample of 1.0m in width and 100 pieces in width direction × 5cm in length are evenly cut to measure 20 weights and thicknesses, and the weight and thickness of CV% is calculated. , 8 to 10 are judged to be good and 10 or more to be defective. Both the weight and weight of CV% should be less than 8 to determine "good". If the weight is inclined toward the bad side, the bad side will be judged.

As will be apparent from the above experiments, according to the present invention, when the MD / CD strength ratio is excellent at 2 or less and the distribution is uniform, a low weight product of less than 30 g / m 2 can be produced, and a high weight product of 30 g / m 2 or more can be produced. Since the distribution and strength ratio are uniform and high, it is possible to provide a high-quality long-fiber nonwoven fabric with high product quality.

Claims (7)

After spinning and cooling, the multifilament obtained by cooling solidification and drawing with high pressure air is charged and opened through ions generated in the form of positive or negative charge through the charging electrode at high voltage, and then the charged multifilament is impinged on the inclined plate at a predetermined angle. And a second plate of the vertical plate, which is a first plate extending vertically from the lower end of the inclined plate and a second plate facing a predetermined distance away from the first plate and having a top higher than the height of the first plate. A method of producing a long fiber nonwoven fabric, the method comprising: colliding and dropping a conveyor belt under suction through a gap between the first plate and the second plate to form a web, and calendering the obtained web to produce a long fiber nonwoven fabric. An apparatus for manufacturing a long fiber nonwoven fabric, comprising: stretching means for stretching a cooling-solidified multifilament after spinning into high-pressure air, charged and opened through ions generated in the form of positive or negative charge through a charging electrode at high voltage to the stretched multifilament Opening means 7, a first plate 72a and a first plate extending vertically from a lower end of the inclined plate rectifying plate 71 in the form of an impingement plate and a lower portion of the opening means 7. A vertical guide rectifying plate 72 which faces a predetermined distance away from the plate and becomes a second plate 72b having a top higher than the height of the first plate, and a vertical guide rectifying plate positioned below the vertical guide rectifying plate 72. An apparatus for manufacturing a long fiber nonwoven fabric, comprising: an air suction vacuum conveyor belt (8) for collecting multifilaments passing through gaps between the first and second plates of the apparatus. 3. The long fiber nonwoven fabric production apparatus according to claim 2, wherein the inclined collision rectifying plate (71) is located about 0 to 100 mm away from the lower end of the opening means and its inclination angle (θ) is 20 to 70 degrees. 3. The long fiber nonwoven fabric manufacturing apparatus according to claim 2, wherein the total size of each of the rectifying plates (71, 72) is 50 to 500 mm. The apparatus of claim 2, wherein the distance between the first plate (72a) and the second plate (72b) is 2 to 50 mm. The long fiber nonwoven fabric manufacturing apparatus according to claim 2, wherein the filament collides with the oblique impact rectifying plate (71) to have a length of 20 to 200 mm. After spinning and cooling, the multifilament obtained by cooling solidification and drawing with high pressure air is charged and opened through ions generated in the form of positive or negative charge through the charging electrode at high voltage, and then the charged multifilament is impinged on the inclined plate at a predetermined angle. And a second plate of the vertical plate, which is a first plate extending vertically from the lower end of the inclined plate and a second plate facing a predetermined distance away from the first plate and having a top higher than the height of the first plate. A long-fiber nonwoven fabric produced by colliding and dropping on a conveyor belt under suction through a gap between the first and second plates to form a web, and calendering the obtained web, the machine direction / lateral direction (MD / CD) A long fiber nonwoven fabric having a strength ratio of 2 or less.

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