KR100680373B1 - Long fiber nonwoven fabric and its manufacturing method - Google Patents

Abstract

According to the present invention, there is provided a non-woven fabric composed of composite long fibers of heterogeneous polymer, a long-fiber nonwoven fabric in which microfibers in which non-woven composite long fibers are divided is irregularly interlaced, and these nonwoven fabrics are not compatible with two melt polymers. A web is formed by a spunbond nonwoven fabric using a spunbond nonwoven fabric using two or more divided composite long fibers having a complex ratio of 2: 8 to 8: 2 and fineness of 1 to 10 denier, and water punching the web using a spunlace method. The nonwoven fabric of the present invention is a high value-added product that satisfies high flexibility and strength at the same time.

Description

Non-woven fabric and preparation method thereof             

1 schematically illustrates an example of an apparatus that may be used to make the nonwoven fabric of the present invention.

Figure 2 is an electron micrograph showing a form of split composite yarn that can be used in the present invention

FIG. 3 is an electron microscope photograph of a state after manufacturing the nonwoven fabric of the split composite yarn of FIG.

4 is a schematic representation of an apparatus used to make a conventional spunbond nonwoven fabric;

5 is a schematic representation of an apparatus used to make a conventional spunlace nonwoven fabric;

* Description of the symbols for the main parts of the drawings *

1: spinneret

2: cooling chamber

3: air extension ejector

4: extension tube                 

5: open means

7: Net Conveyor

8a, 8b: calendar roller

9: water punching means

10: absorption means

11: drying means

12: winder

The present invention relates to a nonwoven fabric, and more particularly, to a fine fibrous nonwoven fabric and a manufacturing method thereof.

Among the manufacturing methods of the nonwoven fabric, the spunbond method and the spunlace method are well known. As shown in FIG. 4, the conventional spunbond long fiber nonwoven fabric provides a high-pressure air ejector 33 after the multifilament yarn Y radiated from the spinning block 31 is cooled and solidified in the cooling chamber 32. ) Is continuously drawn through the drawing tube or the high-pressure air pipe 34 and the opening means 35, and then laminated on the net conveyor 37 in the form of a web. The laminated web is configured to apply heat and pressure simultaneously using a calender roll 38 to impart a certain thickness and physical properties, and then to wind and manufacture the web by winding the roll 39. The long fiber nonwoven fabric produced by such a spunbond method is widely used for industrial purposes because it can produce a stronger and thinner product than a 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 amount and use of a spunbond nonwoven fabric are expanded further.

As shown in FIG. 5, in the conventional short fiber nonwoven fabric manufacturing method by the spunlace method, the web is manufactured by carding the short fibers in the carding means 21, and then the water punching means 22. The high-pressure water stream is sprayed onto the web to entangle the short-fiber web, and the excess water is sucked off from the absorbing means 23, dried in the drying means 24, and then wound up in the winding means 25. It consists of winding up and manufacturing a nonwoven fabric. An example of a method for manufacturing a short fiber nonwoven fabric by a spunlace method will be described in more detail. First, short fibers of 1 to 10 denier and 25 to 100 mm in length are uniformly oriented in the carding means 21 to form a web. The web thus produced has a certain orientation and is vulnerable because it is not entangled. Powering the Web requires some level of entanglement. In the spunlace method, the interlacing method of fibers is to inject the high pressure water stream onto a moving web to entangle the fibers with each other, whereby the nonwoven fabric produced has a certain strength and elongation. This method is also called "water punching method" by using high pressure water flow. Since the nonwoven fabric provided with the predetermined physical properties must remove the excess water, the excess water is firstly removed from the absorbing means 23, and the final product is dried by completely drying the water in the next dryer 24.

In general, there are two methods for imparting entanglement in a single fiber nonwoven fabric, a needle punch method and a spunlace method. The needle punching method uses a steel needle having a protrusion on the surface to reciprocate up and down the web, thereby producing a nonwoven fabric as fibers are entangled in the protrusion on the needle surface. The nonwoven fabric thus produced is generally called needle punch nonwoven fabric. Needle punch nonwoven fabric has the advantage of easy manufacturing because the manufacturing process is simple, but the steel needle is easy to break the fiber during the entanglement process, resulting in poor process continuity due to deterioration of physical properties and dust generation. In addition, due to the characteristics of the needle punch method, it is difficult to produce a lightweight product of 100 g / m 2 or less. On the other hand, the spunlace method can be said to be a method that supplements the disadvantages of the needle punch method. The spunlace method uses a high pressure water stream of 50 kg / cm 2 G or more as a fiber entanglement method, so that damage to the fiber can be very effectively avoided. Therefore, the physical properties of the product to be manufactured is superior to the needle punch method, the surface feel of the product is much more flexible, which is advantageous for the production of high-quality nonwoven fabric. In addition, there is no fear of dust generation during the manufacturing process, so the process continuity is excellent and the productivity is excellent. The weight range of the product to be manufactured can also be covered from low weight (usually 20 g / m 2) to high weight (usually 600 g / m 2), so the flexibility of the equipment is also good.

As described above, the manufacturing process of the nonwoven fabric is classified into two types of short fiber method and long fiber method, and the properties of the manufactured product are different due to the characteristics of the process. That is, the spunbond method can produce a product which is mainly high in strength and relatively thin in the same unit weight. In other words, the two methods above can be said to be in a state where they are compared to each other. In general, the spunbond method is capable of producing a high-strength nonwoven fabric with high productivity, but the touch is hard and thin, whereas the spunlace method is soft and bulky, but weaker than the spunbond method in terms of strength. These disadvantages are difficult to compensate because of the inherent problems of the process itself.

In recent years, the demand for the nonwoven fabric which is excellent in strength and soft in touch is increasing. Nonwoven products of this kind have a problem that is hard to meet by the conventional nonwoven fabric manufacturing method. Typically, the fibers constituting the nonwoven fabric (Fiber or Filament) is used 2 to 10 denier levels, the material is a thermoplastic fiber polypropylene (PP) or polyethylene terephthalate (PET) is used. Even if the nonwoven fabric composed of such fibers is manufactured by the spunbond method or the spunlace method, it is difficult to simultaneously improve the feel and strength of the product.

Accordingly, one object of the present invention is to provide a fine fibrous nonwoven fabric having excellent strength and soft touch.

It is a further object of the present invention to provide a method suitable for producing a nonwoven fabric of the above characteristics.

In order to achieve the above object, the present inventors have produced a web by direct spinning the fineness filament of less than 1 denier by the spunbond method. However, due to the high stress due to the high-speed spinning unique to the spunbond process, the web could not be stably manufactured, so the present inventors have had to give up the fine-seam web manufacturing by direct spinning. However, the present inventors observed a phenomenon in which the epidermis of the filament is damaged by intermittent high-pressure water flow in the water punching process of the spunlace method, and this phenomenon is observed mainly when the low-weight web is treated at high pressure. In view of the above phenomenon, the present inventors manufacture a web made of a split long fiber composite yarn by a spun bond method, and when the web is combined in a spunlace water punching process, the composite yarn is naturally divided by high pressure water flow. The present invention has been completed by knowing that it is possible to easily manufacture a high-strength nonwoven fabric exhibiting a flexible touch that can not be easily simulated by technology.

Therefore, according to the present invention, there is provided a long fiber nonwoven fabric characterized in that the microfibers in which the composite long fibers on the nonwoven fabric are irregularly entangled as a nonwoven fabric composed of a composite long fiber made of different kinds of polymers.

According to the present invention, there is provided a method for producing a long fiber nonwoven fabric characterized in that the thermoplastic synthetic fibers are melt-spun and stretched in high pressure air and then the stretched fibers are dispersed to form a web and high pressure water punching.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 schematically shows an example of an apparatus that can be used to make the nonwoven of the present invention. The device shown is characterized by a combination of a conventional spunbond manufacturing process and a spunlace process. Referring to the process of manufacturing the nonwoven fabric in the above apparatus, first, the multifilament (Y) discharged from the spinneret (1) is cooled and solidified in the cooling chamber (2), and then the air stretching ejector (3) and the stretching pipe ( While passing through 4) is continuously drawn by high pressure air and then dropped through the opening means (5) to be laminated on the net conveyor 7 in the form of a web (web), the laminated web is the first calendar roller (8a) Heat and pressure are simultaneously applied while passing through the first calendar roller 8b to have a constant thickness (spunbond method). Next, the web passing through the calender roller 8b is entangled with each other by the high pressure water flow injected from the water punching means 9 while passing through the water punching means 9, and then passes through the absorbing means 10. Excess water is removed, and after the water is completely dried while passing through the drying means 11 is wound the final product in the winder 12 (spunlace method).

That is, the spunbond method is adopted for the spinning, stretching, and web manufacturing processes of the fibers, and the spunbond method is adopted as the method for joining the manufactured webs, or the spunbond method and the spunlace method are used together. When employing the spunbond method and the spunlace method together for joining the webs, it is preferable to bond them by water punching after fixing under heating and pressure in a calender roller, and it is more advantageous to apply such a method in the present invention. In this case, the fixing in the calender roller may be performed at a temperature at which the fibers may be fused, or may be performed at a temperature lower than this temperature.

The method of the present invention can obtain several advantages by combining the spunbond method and the spunlace method in this way. That is, since the web is produced by the spunbond method, the web can be manufactured in the form of a continuous filament and high strength can be achieved. In the spunlace method, since the nonwoven fabric is manufactured using short fibers having a certain length, there is a limit to increase the strength of the final product. However, in the spunbond method, the filament type nonwoven fabric exhibits higher strength than the single fiber.

In addition, by taking the spin direct form, it is possible to produce fibers of a desired shape at a desired time. In the spunlace method, in order to change the shape of the fiber, it is necessary to prepare a short fiber of a separate desired form in advance, and in some cases, it often occurs when production is impossible depending on the supply and demand of raw materials. However, in the manufacturing process of the present invention, the desired denier (fineness), the form (cross-sectional shape), the material (PP, PET, NYLON, etc.) can be freely changed, and the production can be changed smoothly according to the market demand.

In general, nonwoven fabrics made by the spunbond method have strong but not soft drawbacks. The present invention was solved by introducing a part of the spunlace process to compensate for this disadvantage of the spunbond method. In general, providing the flexibility of the nonwoven fabric produced by the spunlace method is due to the water punching means 9.

There are three factors that determine the flexibility of nonwoven fabrics: material, fineness (denier) and bonding method. If the two factors are the same, the flexibility of the final product is determined by the bonding method. That is, the coupling method adopted by the conventional spun bond method mainly uses the needle punch method or the thermal bonding method. Although the method is widely used in that nonwoven fabric can be easily produced, the needle punch method inevitably damages the fibers, and the thermal bonding method inevitably becomes thin and hard due to the characteristics of the process. In addition, since the needle punch method is suitable for a web bonding method having a certain thickness, it cannot be generally used for low weight products of 100 g / m 2 or less, and the thermal bonding method is not used for high weight products of 100 g / m 2 or more due to heat transfer problems. However, the manufacturing method of the present invention does not require the duplication of the manufacturing method according to the weight which is a problem in the conventional method. That is, in the process of the present invention can be produced while changing the weight freely from low-weight products of 20g / ㎡ or less to ultra-high weight products of 600g / ㎡ or more.

This widening range of products is due to the feature of "water punching". That is, when the high pressure water stream is applied to the web before the bonding is made, the desired pressure is adjusted by adjusting the water pressure according to the weight of the web and the required characteristics of the product to be produced.

When the weight of the desired nonwoven fabric is less than 300 g / m 2, the pressure of the water punching fluid is preferably less than 200 kg / cm 2, and when it is 300 g / m 2 or more, the pressure of the water punching fluid is 200 to 400 kg / cm 2. It is desirable to. For example, a low weight product at a level of 30 g / m 2 sets the water pressure low to a level of 50 to 100 Kg / cm 2 G, and a high weight product of 300 g / m 2 or more is preferably treated at a high pressure of 200 to 400 Kg / cm 2 G or more. If the pressure of the fluid is too high during the processing of low weight products, the fibers constituting the web are repulsed, scattered, and dispersed or separated without forming a nonwoven fabric. On the other hand, if the pressure of the fluid is too low in the processing of heavy products, the bonding force between the fibers is weakened to obtain a nonwoven fabric of the desired strength. At this time, both sides of the web is based on water treatment, some low-weight products may be treated only one side.                     

As such, when the nonwoven fabric is manufactured by the method of the present invention, the nonwoven fabric having the desired quality may be manufactured by satisfying suitable manufacturing conditions. According to the method of the present invention, all products can be processed and produced in a continuous process from low to high weight, and high strength obtained by the spunbond method, and flexible products produced by the spunlace method can be manufactured with high productivity.

In the present invention, the finer the finer the fibers (Y), the more flexible the final product. In other words, when the thickness of the fibers constituting the nonwoven fabric is small, the flexibility naturally increases, but the flexibility is further increased by receiving the water punching treatment of the process of the present invention. In the conventional spunbond method, the fineness of 1 denier can be spun filament, but the flexibility of the final product is reduced as the fibers are bonded or broken through the heat bonding or needle punching process. In addition, the volume of the product (Bulky) is reduced, the quality is also reduced. On the other hand, in the spunlace method, since the web must be manufactured using short fibers, one denier fiber must be prepared first.

However, short fiber manufacturers generally tend to avoid production because less than 2 denier products are less productive and difficult to manufacture. Therefore, it is not easy to purchase raw short fibers at first, and because the fibers are soft and fine, non-woven fabric manufacturing process is not easy because the fibers are often stuck on the roller of the carding machine during the web manufacturing process. to be. However, the nonwoven fabric produced once has the flexibility, high strength, and bulky feeling peculiar to the spunlace method, and can be used for applications requiring high quality.                     

The manufacturing method of the present invention can perform the fineness of the spinning in a consistent process, and since the bonding process of the manufactured web also uses water punching, it is as flexible and continuous filament fiber as the nonwoven fabric produced by the conventional spunlace method. As a result, the strength can produce higher nonwovens. In the present invention, the direct spinning of the lower fineness fibers increases the flexibility of the final product produced. However, in reality, it is not easy to manufacture by spun-bonding filaments of less than 1 denier directly. That is, in the spunbond process adopting a high speed spinning of 5,000 m / min or more, the fine filament of less than 1 denier cannot be manufactured substantially because it causes cutting by excessive concentration of radiation stress.

According to the present invention, however, it is possible to produce a non-woven fabric of finer, less than 1 denier, preferably 0.01-0.5 denier filament fiber, which is extremely flexible and has a sense of volume and exhibits high strength. The spunbond method produces a web made of two or more divided composite long fibers having two or more incompatible polymers in a compound ratio of 2: 8 to 8: 2 and having fineness of 1 to 10 deniers. It can be produced by water punching with. 2 illustrates a photograph taken by an electron microscope of a form of a divided composite yarn for producing a nonwoven fabric having the above characteristics. The composite yarn exemplified is one having a divided cross section of an orange shape. 3 is an electron micrograph showing a state after dividing the composite yarn of FIG. 2.

In order to facilitate the division, the fiber material is composed of two kinds. For example, a combination of nylon and polyester, polypropylene and polyethylene, polypropylene and polyester is mainly used. If the compatibility between materials is good, spinning process is easy but splitting between fibers is not easy by high pressure water flow in water punching process. On the other hand, if the compatibility is poor, unstable phenomena, such as radiation cutting due to separation or twisting stress are generated during spinning, but the division is smooth. Although the combination of polyester and nylon was illustrated in the Example of this invention mentioned later, the effect of this invention is not limited to said combination.

The composite ratio between the fibrous materials also greatly affects the splitability and radioactivity. The more complex the ratio is, the less the splitability is, but the radioactive is safe. On the other hand, the larger the ratio, the better the splitability, but the radioactivity tends to be unstable. Therefore, the composite ratio is determined by considering the fineness of the fiber to be spun and the final fineness after splitting. Preferable compound ratios are about 2: 8-8: 2.

The final fineness after the division is about 0.01 to 0.5 denier, and preferably about 1 to 10 denier before the division. The number of divisions of the fiber cross section varies depending on the type and use of the product, but can be taken from a minimum of 2 to 36. Generally, 16 divisions are used a lot, but they are not fixed.

When the high pressure water flow treatment is performed on the web manufactured by the composite spinning as described above as shown in FIG. 1, the fibers constituting the web can be easily divided to easily produce a fine-grained nonwoven fabric. The nonwoven fabric thus produced is a high quality nonwoven fabric unlike the conventional nonwoven fabric because the denier of the fiber is very thin, soft, voluminous, and high strength unlike the conventional nonwoven fabric. Therefore, it can be used as an artificial leather forge that is not conventionally used as a nonwoven fabric, a high quality wiper, and the like.

Features and other advantages of the present invention as described above will become more apparent from the following examples. However, the present invention is not limited to the following examples.

[Examples 1 to 5]

In the apparatus of FIG. 1, a nonwoven fabric was manufactured by the following procedure.

First, polyethylene terephthalate (PET) having an intrinsic viscosity (IV) of 0.645 and polyamide having a relative viscosity (RV) of 2.45 were melted and extruded at a spinning temperature of 284 ° C. The number of capillaries used in the detention was 30Hole / Cop and the spinnerets (1) were all 6Cop. The discharge amount per capillary hole of the spinneret 1 was fixed at 1.4 g / min. The compound ratio of polyethylene terephthalate and polyamide was tested by continuously changing the level to 10 to 90% for each test type. In addition, the cross section of the fiber to be spun was based on 16 divisions. The denier of the spun fiber was made up to 1 to 5 denier. The multifilament (Y) extruded through the spinneret is cooled and solidified by cooling air of 19 ° C. × 0.55 m / sec. In a quench chamber 2 having a length of 1.5 m, and then placed at a position of 1.7 m in the spinneret 1. It was drawn at high speed with a conventional air ejector 3 installed and then introduced to the carding machine 5. The filament (Y) introduced to the carding machine (5) is a high voltage of 20 kV or more generated by the high voltage generator (5 ') through ions generated in the form of positive or negative charge through the charging electrode. The filament (Y) is charged (Discharge). The charged filaments Y are diffused in the carding machine 5 and then sprayed onto the net conveyor 7 to be seated to produce a spunbond web. At this time, the air pressure of the air ejector was used high-density high-pressure air so that the filament is stretched sufficiently to be more than 5,000m / min, which can exert its own strength. The manufactured web is passed through the primary calender roller 8a and fixed by giving a suitable heat and pressure of 120-200 ° C. in the secondary calender roller 8b. Then, the water punching means 9 performs high pressure water treatment. The moisture was removed to prepare a nonwoven fabric. The machine direction (MD) and width direction (CD) strengths of the prepared nonwoven fabrics and the fineness of the fibers on the nonwoven fabrics were measured, and flexibility was determined by the following method. The measurement results are shown in Table 1 below.

※ Determination of flexibility of non-woven fabrics: Ten pieces of 3.0m wide specimens are cut equally in the width direction 30cm × 30cm in length to measure the weight and thickness. After feeling the touch of the sample by hand, judge and record in 5 units (excellent> good> normal> poor> very poor = 5> 4> 3> 2> 1). Comprehensive records are used to calculate the average score and then judged based on the score. In case of a tie, the player with the higher strength is considered to be excellent.

Comparative Example 1

In the device of Figure 4 by spinning with PET alone to prepare a web, a nonwoven fabric was prepared by bonding the web by thermal bonding method using a calender roll with an adhesive area of 14% level. The thermal bonding temperature was 235-245 degreeC.

Comparative Example 2

Nonwoven fabrics were made in the apparatus of FIG. The raw material used was PET 3.0 denier, 75 mm in length, and the water pressure of the water punching means was 70 kg / cm 2 G.

 division Radiated Fine Islands (De) Compound ratio Fineness of nonwoven fibers (De) Properties Total Strength (MD + CD) PET PA PET PA weight flexibility Strength (MD) Kg / 5cm Strength (CD) Kg / 5cm Heavy rain Example 1 3 50 50 0.2 0.2 50 4.5 22 21 1.1 43 Example 2 3 70 30 0.26 0.11 50 4.3 24 20 1.2 44 Example 3 3 30 70 0.11 0.26 50 4.2 23 21 1.1 44 Example 4 One 50 50 0.06 0.06 100 4.8 44 38 1.2 82 Example 5 5 50 50 0.31 0.31 100 4.1 46 38 1.2 84 Comparative Example 1 3 100 0 3 0 50 1.8 25 21 1.2 46 Comparative Example 2 3 100 0 3 0 50 3.5 23 17 1.3 40

As can be seen from the above experimental results, according to the present invention, it is possible to produce a high quality fine fibrous nonwoven fabric having excellent flexibility and high strength.

Claims (7)

A nonwoven fabric composed of composite long fibers of heterogeneous polymers, wherein the long fiber nonwoven fabric is characterized by irregular interweaving of ultrafine fibers in which composite long fibers on a nonwoven fabric are divided. The long fiber nonwoven fabric according to claim 1, wherein the composition ratio of the heteropolymer of the composite long fiber is 2: 8 to 8: 2. The long fiber nonwoven fabric as claimed in claim 1, wherein the fineness of the fine fibers is 0.01-0.5 denier. In the production of a long fiber nonwoven fabric, a method of producing a long fiber nonwoven fabric, characterized in that the melt-spun thermoplastic synthetic fibers are drawn in high-pressure air and then dispersed to form a web and high pressure water punching. 5. The thin fibrous nonwoven fabric as claimed in claim 4, wherein the synthetic fibers are composite long fibers in which two kinds of polymers having incompatibilities are compounded at a compound ratio of 2: 8 to 8: 2. The method for producing a fine fibrous nonwoven fabric according to claim 4, wherein the desired nonwoven fabric has a weight of less than 300 g / m 2 and a water punching fluid of less than 200 kg / cm 2. The method for producing a fine fibrous nonwoven fabric according to claim 5, wherein the desired nonwoven fabric has a weight of 300 g / m 2 or more and a water punching fluid has a pressure of 200 to 400 kg / cm 2.

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