KR19990009821A - Manufacturing method of long fiber nonwoven fabric and apparatus therefor - Google Patents

Abstract

In the present invention, in manufacturing a long fiber nonwoven fabric, the thermoplastic resin is melt-spun and cooled, and then heat-treated by passing through a heating vessel of a standard satisfying the following conditions (I) to (III), followed by stretching through an air ejector. According to the present invention, a long fiber nonwoven fabric having excellent physical properties and having high strength can be economically manufactured.

(Ⅰ). Length: 1.1 ~ 4.0m

(II). Inner diameter: 20 ~ 60mm

(III). Temperature: Glass transition temperature (Tg) to melting temperature (Tm)

Description

Manufacturing method of long fiber nonwoven fabric and apparatus therefor

The present invention relates to a method for manufacturing a long fiber nonwoven fabric and a device thereof, and more particularly, to pass an air ejector after cooling and heat treatment, and to install a heating tube satisfying a specific condition under the spinneret to relatively reduce the discharge yarn at low temperature. The present invention relates to a method for producing a long fiber nonwoven fabric having excellent uniformity and physical properties, and a device thereof, characterized by heat treatment for a long time.

Long fiber nonwoven fabric has better mechanical properties and better form stability and thermal stability than short fiber nonwoven fabric, so it is widely used for various construction materials, civil engineering materials, agricultural materials, automobile materials, and many other industrial applications. It is a trend.

In general, in the manufacture of a long fiber nonwoven fabric, as shown in Figure 1, the thermoplastic resin is melted at a high temperature using a molten spinneret and then released through the spinning block (1) and the released thread (Y) is cooled chamber Cool using (2). Subsequently, the air ejector 3 is stretched using high pressure compressed air, and then passes through the thread guide tube 4, and the multi-dispersion is dispersed in the carding device 5 to be integrated on the conveyor 6 so that the web WEB ), And then by hot pressing using an embossing roller (7) to produce a nonwoven fabric and finally wound on the winder (8).

In the manufacturing process of such a long fiber nonwoven fabric, in particular, the physical properties of the filaments constituting the nonwoven fabric must be properly adjusted because it is directly related to the physical properties of the entire nonwoven fabric. In general, a method of increasing the air pressure supplied to the air ejector 3 is used as a method for improving the physical properties of the extruded filament. However, excessively increasing the air pressure raises the frictional resistance between the air and the filament, resulting in a problem that the filament is cut. This phenomenon is slightly improved by reducing the radiation field, ie the distance from the spinning block (1) to the top of the carding machine (5), because the area of contact between the filament and the air is reduced, resulting in a decrease in the amount of accompanying airflow. to be. However, it is difficult to expect an improvement over a certain limit because it is not possible to reduce the radiation field beyond the freezing point of the filament.

As an alternative to solve this problem, Japanese Patent Laid-Open No. 6-264327 provides a heating tank between the lower part of the firing point and the air ejector 3 to reduce the air friction tension of the filament running at high speed, and improve the physical properties and the uniformity. A method of doing this is disclosed. Specifically, the method is to place a heating tube of 0.2 ~ 1.0m between the lower end of the freezing point of the discharged filament and the air ejector 3 in order to reduce the frictional resistance with air (Tm-100 ℃) It is characterized by thermal stretching at a high temperature between (Tm + 200 ° C.). The freezing point of the thermoplastic resin is determined as a function of complex factors such as the type of resin used, spinning temperature, air flow rate and temperature of the cooling chamber, spinning speed, discharge amount, and spinning field. ) Is known to be 0.6 ~ 1.8m, polypropylene 0.4 ~ 1.6m level. That is, in the method of Japanese Patent Laid-Open No. 6-264347, since a hot drawing zone is installed at a fixed position at the lower end of the freezing point to process a filament traveling at a high ambient temperature, the drawing resistance is reduced and the orientation is increased. Naturally, the filament's physical properties are improved. In addition, it is possible to draw in high orientation with low drawing force, so it is possible to lower the pressure of the compressed air to be used, thus reducing the air consumption and economical. As described above, the method of Japanese Patent Laid-Open No. 6-264347 can solve the cutting phenomenon of filament due to high tension during spinning, which has been a problem in the past, and can improve various properties such as uniformity, mechanical performance, and dimensional stability. Have

In Japanese Patent Laid-Open No. 6-264347, however, the size of the heating tube disposed downstream of the spinneret is small and the temperature is high, while the filament speed is higher than 50,00 m / min, so that the entire filament is not uniformly heat treated. In other words, the filament located on the outside is always heat-treated first than the inside, so the physical properties are improved, but the filament located on the inside is less effective in heat treatment, so the physical properties are relatively poor and the cutting effect is more frequent. Low denier yarns with low deniers and more filaments have more varieties. In short, the overall physical properties and the cut rate are improved but not uniform, so there is still a high variation of the cut rate and property. If this property variation occurs, even after the hot pressing process in the post-process, the shape stability of the final product nonwoven fabric is poor due to the non-uniformity of the stress potentially retained inside the filament. In addition, since the heat treatment is performed at a high temperature above the melting point of the thermoplastic resin, the atmospheric temperature is increased due to the high temperature air exiting from the heating tube, which damages the working environment, and also wastes energy. Moreover, also in the method of heat-treating a heating cylinder, the system which ejects superheated steam in the running direction of the thread which drives at high speed, and in fact, superheated steam does not penetrate smoothly inside the thread | bath Y. Due to this, the physical property deviations of the outside and inside of the yarn Y continue to utter, and the problem of truncation does not improve.

SUMMARY OF THE INVENTION An object of the present invention is to overcome the above-mentioned problems in the prior art, which is a process due to cutting, which is a problem of conventional Japanese Laid-Open Patent Publication No. 6-264347 by passing through a heating vessel after melt spinning cooling and then passing through an air ejector. To solve the instability and physical properties of the non-uniformity, by providing a heat treatment for a relatively long time at a low temperature to provide a method and apparatus for producing a long-fiber non-woven fabric excellent in physical properties and can reduce the manufacturing cost.

1 is a schematic view of a conventional long fiber nonwoven fabric manufacturing method,

Figure 2 is a schematic diagram of a method for producing a long fiber nonwoven fabric of the present invention.

Explanation of symbols for main parts of the drawings

1: Radiation Block Y: Emission Yarn

2: Cooling chamber 3: Air ejector

4: Thread guide tube 5: Opening device

6: Conveyor 7: Embossing Roller

8: winder 11: heater

That is, in the present invention, in manufacturing a long fiber nonwoven fabric, the thermoplastic resin is melt-spun and cooled, and then passed through a heating tube of a standard satisfying the following conditions (I) to (III), followed by heat treatment, followed by an air ejector. It is to provide a method for producing a long fiber nonwoven fabric characterized in that.

(Ⅰ). Length: 1.1 ~ 4.0m

(II). Inner diameter: 20 ~ 60mm

(III). Temperature: Glass transition temperature (Tg) to melting temperature (Tm)

Hereinafter, the present invention will be described in more detail.

In other words, the flow of the unit process of the nonwoven fabric manufacturing process is changed. In detail, the melt spinning, cooling, and heat treatment are performed through a heating tube, followed by an air ejector, thereby decreasing the tension of the continuously running filament bundle to monofilament. It can prevent the cutting of and improve the heat treatment effect to improve the uniformity between the inner and outer layers of the filament bundle can improve the shape stability of the nonwoven fabric in the post-process.

In the present invention, in order to uniformly heat-treat the discharge yarns running at high speed, the length and inner diameter specifications of the heating tube 11 are important. It is preferable that the length of the heating cylinder 11 used by this invention exists in the range of 1.1-4.0 m. If the length of the heating tube is less than 1.1m, the heat treatment may become uneven. If it exceeds 4.0m, the radiation field may be too long, causing the radiation tension to increase due to friction with air, which may cause the cutting. do. In particular, the length of the heating tube 11 used in the present invention is 1.5 to 2.5m is most preferable in terms of operation and physical properties.

In the present invention, the inner diameter of the heating cylinder may be made as small as possible as long as the filament traveling at high speed does not contact the inner surface of the heating cylinder 11. That is, the inner diameter of the heating cylinder 11 used in the present invention is 20 to 60 mm, preferably 30 to 50 mm. If the inner diameter of the heating tube exceeds 60mm, a temperature gradient occurs between the inner surface of the heating tube 11 and the center where the filament travels, so that the filaments may be heat treated at different temperatures, resulting in uneven physical properties. On the contrary, if the inner diameter of the heating tube is less than 20 mm, the filament running at high speed may touch the inner surface of the heating tube 11, so that cutting may occur. Therefore, in the present invention, the inner diameter of the heating tube is preferably within the above range.

In the present invention, the temperature control of the heating tube 11 is also important, and it is preferable to heat-treat the discharge thread at a temperature between the glass transition temperature (Tg) and the melting temperature (Tm). This temperature range is usually 100 to 200 ° C, more preferably 112 to 160 ° C. The heat treatment temperature can often be changed by the discharge amount, the number of filaments, the spinning speed, etc., but it should not be performed at a high temperature exceeding the melting temperature. That is, when the heat treatment using the heating tube 11 of the present invention at a high temperature exceeding the melting temperature, it is possible to obtain an effect that the elongation is improved and the trimming is reduced and the radioactivity is improved, but excessive heat treatment to the filament Since the crystallization inside the filament is increased, the elongation is lowered and the strength is also lowered, the overall non-woven fabric feels hard and physical properties. On the contrary, if the temperature of the heating tube 11 is less than the glass transition temperature, sufficient heat treatment effect is not given to the filament, and thus the physical properties as well as the trimming phenomenon are not improved.

The process of the present invention will be described in detail with reference to the drawings.

In the case of manufacturing the long fiber nonwoven fabric according to the present invention, the thermoplastic resin filament thread yarn Y discharged from the spinning block 1 is cooled and solidified by cold air in the cooling chamber 2. Subsequently, the solidified thread Y is guided to the heating cylinder 11, and the method of communicating the thread of yarn Y is naturally performed by the high-pressure air output of the air ejector 3 at the bottom of the heating cylinder 11. The yarns heat-treated in the heating tube 11 pass through the air ejector 3 and are randomly distributed by the carding machine 5 to be integrated on the conveyor belt 6 to form a web WEB. The carding machine 5 of the present invention can be used in both corona discharge and triboelectric discharge. The web formed on the conveyor belt 6 is heat-bonded by the embossing roller 7 at a high temperature of 200 ° C. or higher and then wound on the winder 8 to become a final product.

As the type of thermoplastic resin usable in the present invention, polyester, nylon, polypropylene, polyethylene and the like can be used.

The heating cylinder 11 used in the present invention may use the heating apparatus disclosed in Korean Utility Model Registration Application No. 93-15083, and the method of installing the heating cylinder and the test example used are Korean Patent Application No. 93-22478 93-24921, 92-16385, and 94-14474 can be used, respectively.

Another aspect of the present invention is a heating tube for manufacturing a long fiber nonwoven fabric comprising a pipe, a superheated steam inlet pipe, a pressure storage chamber, and an inclined steam hole, characterized by satisfying the following conditions (IV) and (V). It is to provide a heating tube for producing a long fiber nonwoven fabric.

(IV). Length: 1.1 ~ 4.0m

(V) .Inner diameter: 20 ~ 60mm

In the present invention, in order to uniformly heat-treat the discharge yarn running at high speed, it is preferable that the length and the inner diameter of the heating tube of the present invention are within the above range.

In the conventional heating apparatus, the temperature gradient inside the heating apparatus is inevitably generated by the instantaneous high temperature heat treatment of the yarn which runs at high speed. As a result, the heat treatment of the filament is non-uniform, causing variation in physical properties. The nonwoven fabric produced has the advantage that the fineness of the monofilament is uniform and the strength is high due to the uniform heat treatment of the heating vessel.

The long fiber nonwoven fabric produced by the method of the present invention has excellent physical properties and high strength of the final nonwoven fabric, so that it can be used for civil engineering, construction, agriculture, and other industrial roads. In addition, it is possible to manufacture the finer filament at a lower air ejector pressure due to the low stretching tension, thereby reducing the production cost and easily manufacturing the high strength nonwoven fabric.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples are for illustrative purposes only and the present invention is not limited to the following Examples.

Example 1

After melt extrusion of a polyester chip having an intrinsic viscosity (IV) of 0.65 using a conventional melt spinneret at a spinning temperature of 288 ° C. using the nonwoven fabric manufacturing apparatus of FIG. 2, the diameter of the capillary was 0.25 mm and the number of capillaries was Through the spinneret, which is 40 pieces / heating tube, the discharge amount was appropriately controlled so that the final fineness was 2-3 denier. Subsequently, cooling was performed using a cooling chamber having a length of 1.1 m, a cooling air temperature of 19 ° C., and a speed of 0.5 m / sec. Then, heat treatment was performed using a heating tube 11 having a length of 1.5 m, an inner diameter of 30 mm, and an internal temperature of 140 ° C. installed at a position 1.5 m away from the spinneret. At this time, the heating method of the heating tube 11 adopted the fruit heating method. An air ejector 3 was installed at the lower end of the heating tube 11 to stretch the filament using high pressure compressed air. A corona discharge device was installed at the bottom of the air ejector 3 to charge the stretched multifilament, randomly disperse, and integrate it on the net conveyor 6 to manufacture a web. The web WEB was again hot-welded under conditions of a temperature of 230 ° C., a roller line pressure of 50 kg / cm, and an embossing area of 12% in the embossing roller 7, and then a final weight of 50 g / s9 in the winder 8. The long fiber nonwoven fabric of this invention was manufactured by winding up and adjusting speed so that it might become m. The physical properties and the radioactivity of the prepared long fiber nonwoven fabric were evaluated and the results are shown in Table 1 below.

EXAMPLES 2-11

The manufacturing conditions and the size and installation position of the heating tube were changed in the same manner as in Example 1 while changing as shown in Table 1 to prepare a long fiber nonwoven fabric and the results of the evaluation of the overall properties are shown in Table 1 below. .

Comparative Examples 1 to 8

The nonwoven fabric manufacturing apparatus of FIG. 1 was used and the specifications and installation position of the heating tube having an inner diameter of 50 mm were changed as shown in Table 2, and other conditions were performed in the same manner as in Example 1 to prepare a long fiber nonwoven fabric. The results of evaluating the various physical properties are shown in Table 2 below. In this comparative example, the heating system adopts a system in which the superheated steam is ejected like a thread running inside the heating tube.

Through the results of Table 1 and Table 2, it can be confirmed that the long fiber nonwoven fabric produced by the method of the present invention is superior in physical properties and superior strength than the long fiber nonwoven fabric of the comparative example.

Claims (3)

In manufacturing a long fiber nonwoven fabric, the method of producing a long fiber nonwoven fabric, characterized in that the thermoplastic resin is melt-spun and then cooled, heat treated by passing through a heating tube, and stretched by passing through an air ejector. The method for producing a long fiber nonwoven fabric according to claim 1, wherein the heat treatment heating tube satisfies the following conditions (I) to (III). (Ⅰ). Length: 1.1 ~ 4.0m (II). Inner diameter: 20 ~ 60mm (III). Temperature: Glass transition temperature (Tg) to melting temperature (Tm) A heating tube for manufacturing a long fiber nonwoven fabric, comprising a pipe part, a superheated steam air inlet pipe, a pressure storage chamber, and a gradient steam hole, and a heating tube for manufacturing a long fiber nonwoven fabric, characterized by satisfying the following conditions (IV) and (V). . (Ⅵ). Length: 1.1 ~ 4.0m (Ⅴ). Inner diameter: 20 ~ 60mm