KR102247574B1 - Manufacturing method of melt-spinning type nonwoven web and nonwoven web products manufactured thereby - Google Patents

Abstract

The present invention relates to a method for manufacturing a melt-spun nonwoven fabric and a microfiber nonwoven web produced therefrom.
The present invention is a method for producing a melt-spun nonwoven fabric in which fibers melt-spun through a spinning nozzle in which a thermoplastic polymer includes at least one nozzle hole is collected with a high-speed air flow, wherein the melt-spun fibers are provided directly under the spinning nozzle when spinning. As it passes through the heater for local heating of the nozzle, it is instantaneously subjected to local high temperature heat treatment higher than the spinning temperature, thereby lowering the melt viscosity of the thermoplastic resin discharged from the nozzle hole and the elongation viscosity on the radiation without reducing the molecular weight, thereby reducing the fiber compared to the conventional spunbond nonwoven fabric. It is possible to provide a fine fiber nonwoven web.

Description

Manufacturing method of melt-spun nonwoven fabric and ultrafine fiber nonwoven web manufactured therefrom {MANUFACTURING METHOD OF MELT-SPINNING TYPE NONWOVEN WEB AND NONWOVEN WEB PRODUCTS MANUFACTURED THEREBY}

The present invention relates to a method of manufacturing a melt-spun nonwoven fabric and a microfine fiber nonwoven web produced therefrom, and more particularly, a thermoplastic polymer melts-spun fiber through a spinning nozzle including at least one nozzle hole is collected in a high-speed air stream. In one melt-spinning nonwoven fabric manufacturing method, the melt-spun fiber is passed through a nozzle local heating heater provided directly under the spinning nozzle during spinning, and is subjected to local high temperature heating at an instant higher than the spinning temperature, and is discharged from the nozzle hole without lowering the molecular weight. The present invention relates to a method for manufacturing a melt-spun nonwoven fabric in which fibers are finer compared to the prior art by lowering the melt viscosity and the elongation viscosity in the radiation phase of a thermoplastic resin, and an ultrafine fiber nonwoven fabric web produced therefrom.

Non-woven fabrics are used in a wide range of fields, such as medical, industrial materials, civil engineering and construction materials, agricultural and horticultural materials, life-related materials, and medical hygiene materials. Among non-woven fabrics, long-fiber nonwoven fabrics have various advantages in that physical properties are uniform and superior to short-fiber nonwoven fabrics, and productivity is also high in terms of manufacturing nonwoven fabrics. In order to obtain a nonwoven fabric having excellent functionality while taking advantage of such a long fiber nonwoven fabric, many studies and developments have been attempted so far to make the thickness of the fibers constituting the nonwoven fabric as thin as possible.

Therefore, the fineness of nonwoven products is one of the important issues.As the fibers become finer, the specific surface area of the nonwoven products increases rapidly, thereby maximizing liquid absorption, softness or flexibility, and filtration performance. It will be useful for improving performance in the field.

Effective manufacturing methods of nonwoven fabrics, which are directly related to melt spinning, include the spunbond method and the melt blown method.

The spunbond method is a manufacturing method for obtaining a long fiber nonwoven fabric, and since it was first industrialized by DuPont in 1959, it has been widely used as a spunbond nonwoven fabric until now.

1 is a schematic diagram of a method for manufacturing synthetic fibers by a general melt spinning process, wherein the thermoplastic polymer supplied to the hopper 100 is melted and discharged by the extruder 101 and is extruded and spun from the nozzle 103 of the pore for cooling and solidification. And a refining process, and in the refining process, a fiber is manufactured using a winding unit 105 using a rotating roll 104.

FIG. 2 is a schematic diagram of a method of manufacturing a nonwoven fabric by an open spunbond method using melt spinning, in which fibers are pulled by a high-speed air flow by an ejector 204 instead of a winding part using a rotating roll in the refining process of FIG. 1 The spunbond nonwoven fabric can be obtained in the form of a web on the movable collecting conveyor belt installed under the ejector and being finely divided.

3 is a schematic diagram of a method of manufacturing a nonwoven fabric by a closed spunbond method using melt spinning.In the refining process of FIG. 1, instead of a winding part using a rotating roll, the fibers are cooled with air supplied directly under the nozzle in a closed duct. As it flows downstream, the passage area of the duct is drastically reduced to maximize the air passing speed. Similar to the open type ejector, the fibers are pulled and refined by a high-speed air flow, and the web on the moving trapping conveyor belt installed under the duct It is possible to obtain a spunbond nonwoven fabric on the (web) phase.

Therefore, the final running speed or denier of the fiber on the radiation produced by the melt spinning method is controlled by the spinning conditions such as the discharge amount of the nozzle hole or the winding speed, but in the case of the spunbond nonwoven fabric, the discharge amount of the nozzle hole and the ejector It depends on the air pressure and amount of output.

The nonwoven fabric made of continuous filament fibers manufactured by the spunbond method has excellent mechanical strength, but has a small surface area due to a large fiber diameter, and lacks fluid absorption, flexibility, and filtration properties.

Therefore, it has been reported that for the fineness of the nonwoven fabric, if the air pressure of the ejector is increased or the discharge amount of the nozzle hole is decreased in the manufacturing process by the spunbond method, the fiber speed increases and a finer fiber nonwoven fabric can be obtained [ Non-Patent Document 1].

4 is a schematic diagram of a method of manufacturing a nonwoven fabric by a melt blown method using melt spinning.

The melt blown method uses melt spinning similar to the spunbond method [Non-Patent Document 2, Patent Document 1], but has a small fiber diameter compared to the sponbond nonwoven fabric, which is excellent in flexibility and has a large surface area. This melt blown method melts a low-molecular-weight thermoplastic polymer with a low viscosity for fineness, and when discharged from the nozzle, high-temperature air is applied to the vicinity of the nozzle at a speed close to the speed of sound. It is possible to obtain ultra-fine nonwoven fibers.

However, since the ultrafine fiber nonwoven fabric obtained from the melt blown method consumes very large energy in the process and uses a low-molecular-weight thermoplastic polymer for fineness, its mechanical strength is low, so it is mainly combined with conventional spunbond rather than used alone. I'm using it.

In addition, microfibers can be prepared using the electrospinning method. After dissolving the polymer in a solvent, the solvent is volatilized and removed at the same time as spinning by a voltage difference under a high-pressure electric field, thereby obtaining nano-sized microfibers. However, when the electrospinning method is used, productivity is greatly degraded, and it is difficult to remove residual solvent, and thus it may be limited to the application of sanitary materials and filters, and the physical properties are very weak, so that it is mainly used in combination with conventional spunbond.

As another method, in the flash spinning method, a polymer is dissolved in a solvent such as liquefied gas at high pressure at a higher temperature than the melting point to make it uniform, and then, when the pressure is slightly reduced in front of the nozzle outlet, the phase is separated into two components. When discharged into the atmosphere at room temperature and pressure, the solvent rapidly gasifies and flows at supersonic speed and vaporizes at the same time. At this time, the remaining polymer is solidified and stretched to obtain a 0.1 denier class ultrafine fiber nonwoven fabric having excellent physical properties [Patent Document 2].

However, there is a problem that the process is very complex and difficult to control, and there is a limitation in application other than the olefin polymer series.

As shown in FIG. 1, in the melt spinning method for producing synthetic fibers, a polymer of a polymer is melted by heating to a temperature higher than its melting point, and then extruded from a spinning nozzle into air to cool, thereby producing a fibrous shape. At this time, fiber properties, particularly high strength synthetic fibers, can be obtained by a stable cooling method for the spinning fibers discharged from the spinning nozzle, and conventional studies control the formation behavior of the fiber structure through molecular orientation and crystallization of the cooled and solidified fibers. , It has been progressed to realize the high strength of the fiber by delaying the cooling.

As an example, local heating by the direct thermal insulation method of the radiation nozzle or the method of local heating by laser irradiation under the radiation nozzle is being carried out. Although it is possible to heat the fiber part, it is a method close to the level of insulation rather than heating, and there is a problem in that the entire spinning fiber cannot be uniformly heated.

Therefore, since PET and nylon-based non-liquid crystalline thermoplastic polymers have a complex structure in which polymer chains are entangled in amorphous random coils in a molten state, high shear stress and subsequent draw ratios (draft and draw ratio, etc.) are reduced in the spinning nozzle. Even if applied, due to the structure entangled in a random coil shape, the molecular entanglement structure in the molten polymer could not be controlled, and thus complete orientation crystallization (high strength) could not be achieved.

Meanwhile, the present inventors previously designed a nozzle heating unit capable of optimizing the local heating method directly under the spinning nozzle through which the melted resin is spun after spinning in the melt spinning process, and the multifilament radiated in the vicinity of the hole of the spinning nozzle and directly under the spinning nozzle. It has been reported that the mechanical properties such as strength and elongation of synthetic fibers are improved by controlling the molecular chain entanglement structure in the molten polymer by instantaneous local high temperature heating of the entire yarn [Patent Document 3].

Thus, in order to improve the problem of the conventional microfiber nonwoven fabric manufacturing method, the present inventors introduced the instant local high temperature heating method of the fibers directly or indirectly in the vicinity of the hole of the spinning nozzle and directly under the spinning nozzle in the melt spinning process of the spunbond method, By lowering the pressure of the spinning nozzle, lowering the fiber tension between the spinning nozzle and the ejector, effectively controlling the entangled structure of molecular chains in the polymer without lowering the molecular weight, increasing the fiber spinning speed in the ejector, compared to conventional spunbond or melt blown nonwoven fabrics. By confirming that it is possible to obtain a microfiber nonwoven fabric having a low fineness, the present invention was completed.

1. Republic of Korea Patent Publication No. 1999-71772 (published on September 27, 1999) 2. US Patent 3,227,794 (announced on Jan. 4, 1966) 3. Korean Patent No. 1858550 (announced on May 17, 2018)

1. H. Ishihara, et al., “Computer Simulation of Multi filament Air Jet Melt Spinning”, Polymer Process, 4, 91-95 (1989) 2.Melt blowing-One-Step WEB Process for New Nonwoven Products: Tappi, 1973, 56, 74-77

An object of the present invention is to provide a method of manufacturing a melt-spinning nonwoven fabric that optimizes the instantaneous local high-temperature heating method of a spinning nozzle when spinning in a melt spinning process.

Another object of the present invention is to provide a nonwoven web of ultrafine fibers manufactured from the above manufacturing method.

Another object of the present invention is to provide a use including the ultrafine fiber nonwoven web produced from the above manufacturing method.

The present invention is a method for producing a nonwoven fabric by a melt-spinning spunbond method in which fibers melt-spun through a spinning nozzle in which a thermoplastic polymer includes at least one nozzle hole is collected with a high-speed air stream,

As the melt-spun fiber passes through the nozzle heating part provided directly under the spinning nozzle during spinning, the temperature difference compared to the pack body temperature is instantaneously localized at a temperature of 0.1 to 1,000°C. Provides a manufacturing method.

In the above, the number of hole-type heater holes in which the nozzle local heating heater is spaced within 1 to 300 mm from the center of the nozzle hole may be formed in a number corresponding to at least one nozzle hole.

As another type, when the nozzle hole is formed in a plurality of hole layers within the same radius, when the nozzle hole is formed in a band-shaped type inserted between the adjacent hole layer-hole layer, the nozzle local heating heater is within 1 to 300 mm from the center of the individual nozzle hole. A strip-shaped heater hole arranged in a row may be formed.

The thermoplastic polymer used in the method for manufacturing the melt-spun nonwoven fabric of the present invention is polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polycyclohexanedimethanol terephthalate (PCT). , A polyester-based polymer selected from the group consisting of polyethylene naphthalate (PEN) and polyarylate; Polyamide polymer selected from nylon 6, nylon 6,6, nylon 4 and nylon 4,6; Or a polyolefin-based polymer selected from polyethylene or polypropylene; Polyphenylsulfite (PPS); Single or a mixture of two or more selected from among may be used.

In the method of manufacturing the melt-spun nonwoven fabric of the present invention, the nozzle heating part for instant local high temperature heating treatment of the melt-spun fibers is located at -50 (into the pack body) to 300 mm (out of the pack body) based on the lower part of the pack body. The insertion depth of the heater for local heating of the nozzle that is in contact with or partially inserted into the lower part and the lower part of the spinning nozzle is 0 to 50 mm, the length of the heater for local heating of the nozzle is 5 to 500 mm, and the nozzle heating part is It is formed including an insertion depth of the heater for partial heating of the nozzle partially inserted in the lower part, and an extension length of the heater for heating of the nozzle, which is extended from the insertion depth.

The additional extension distance of the lower surface of the nozzle body may be 0 to 100 mm, and the distance between the extended sections may be 0 to 100 mm.

Preferably, the spinning nozzle may be provided with a fluid mixing device in a flow path pipe above the hole.

The present invention provides a microfine fiber nonwoven web in which a polypropylene (PP) polymer having a melt viscosity (MFI) of 3 to 900 from the method of manufacturing a melt-spun nonwoven fabric is finely formed by local high temperature heating treatment at the time of spinning.

Fineness in the ultrafine fiber nonwoven web satisfies the fineness or less calculated by the following equation 1.

Equation 1

Fineness (㎛) = 94 × A ^(-0.71)

In the above, A is the melt viscosity of the fibers constituting the spunbond nonwoven fabric when using pure polypropylene (PP) polymer without additives or modifier components.

In addition, the present invention provides a microfine fiber nonwoven web made of fine fiber by instantaneous local high temperature heating treatment when a polyethylene terephthalate (PET) polymer having an intrinsic viscosity (IV) of 0.5 to 3.0 from the method of manufacturing the melt-spun nonwoven fabric described above is spun. do.

Fineness in the ultrafine fiber nonwoven web satisfies the fineness or less calculated by the following equation (2).

Equation 2

Fineness (㎛) = (34 × B)-12.7

In the above, B is the intrinsic viscosity of the fibers constituting the spunbond nonwoven fabric when using pure polyethylene terephthalate (PET) polymer without additives or modifier components.

The present invention introduces the instant local high temperature heating method of the fibers directly or indirectly in the vicinity of the hole of the spinning nozzle and directly under the spinning nozzle in the melt spinning process of the spunbond method, so that the fibers are finer than the conventional spunbond nonwoven fabric. Can provide.

Therefore, by using the conventional spun-bond manufacturing process as it is, it is possible to mass-produce high value-added, high-functional ultra-fine fiber nonwoven fabric with low initial investment cost and low cost.

In addition, the manufacturing method of the melt-spun nonwoven fabric of the present invention is to satisfy the same diameter and physical properties as the nonwoven fabric manufactured from the conventional spun-bond manufacturing process, each of the fibers in the molten state discharged from the spinning nozzle. As the spinning speed or the drawing speed increases due to local heating passing through the heating hole, the discharge amount of the initial thermoplastic polymer can be increased, so that the productivity of the nonwoven fabric can be improved.

In particular, the method of manufacturing the melt-spun nonwoven fabric of the present invention is a high-viscosity thermoplastic polymer that was difficult to spin in the past by subjecting the melt-spun polymer to a local high temperature heat treatment directly in the hole, thereby lowering the viscosity (pack pressure) to the extent that it is possible to spin the ultrafine fiber nonwoven web. to provide.

It is particularly useful for filter materials or sanitary materials including ultrafine fiber nonwoven webs produced from the method for producing a melt-spun nonwoven fabric of the present invention.

1 is a schematic diagram of a method for manufacturing a synthetic fiber by a general melt spinning process,
2 is a schematic diagram of a method for manufacturing a nonwoven fabric by an open spunbond method using a melt spinning method,
3 is a schematic diagram of a method of manufacturing a nonwoven fabric by a closed spunbond method using a melt spinning method,
4 is a schematic diagram of a method of manufacturing a nonwoven fabric by a melt blown method using melt spinning,
5 is an enlarged view provided with a nozzle part and a heater for warming at the bottom of the nozzle in a general melt spinning process,
6 is a cross-sectional view taken along the line III-III of FIG. 5 and is an embodiment of a general hole type,
7 is an enlarged view of a nozzle heating unit provided with a nozzle unit in the melt spinning process of the present invention and a heater for local heating of the nozzle directly under the nozzle,
FIG. 8 is a cross-sectional view taken along line I-I of FIG. 7, which is an embodiment of a hole type of a heater for heating a nozzle.
Fig. 9 is a cross-sectional view taken along line I-I in Fig. 7, showing another embodiment of the hole type of the heater for nozzle localized heating.
Fig. 10 is an enlarged view of a nozzle heating unit provided with a nozzle unit in a melt spinning process according to another embodiment of the present invention and a heater for local heating of the nozzle directly under the nozzle.
Fig. 11 is a cross-sectional view taken along line X-X' in Fig. 10, showing another embodiment of the hole type of the heater for nozzle localized heating.

Hereinafter, the present invention will be described in detail.

5 is a view showing a nozzle part in a general melt spinning process, a pack body heater 300 installed outside the pack body 200 and the pack body 200 to provide a heat source to the pack body, and the pack body 200 ) Is installed in the spinning nozzle 100 for spinning the thermoplastic resin in a molten state, and a plurality of spinning holes 111 are formed in the lower portion of the spinning nozzle, so that the thermoplastic resin is melt-spun to form fibers. However, in this case, there is a limit to providing fine fibers without changing the properties of the thermoplastic resin.

The present invention is a method for manufacturing a nonwoven fabric by a melt-spun spunbond method in which fibers melt-spun through a spinning nozzle in which a thermoplastic polymer includes at least one nozzle hole is collected with a high-speed air stream, when the melt-spun fibers are spun As it passes through the nozzle local heating heater 41 of the nozzle heating unit 40 provided directly under the spinning nozzle, the temperature difference compared to the pack body temperature is instantaneously localized at a temperature of 0.1 to 1,000°C, providing a method of manufacturing a melt-spinning nonwoven fabric. do.

The heater 41 for local heating of the nozzle of the present invention has a temperature difference of 0.1 to 1,000° C. compared to the temperature of the pack body 20, and is provided at least the same as the temperature of the pack body 20 or at a high temperature.

In addition, the spinning nozzle 32 is fixed to the pack body 20 maintained at 50 to 400°C from the heat source of the pack body heater 10, and the temperature of the spinning nozzle 32 is the same as the temperature of the pack body heater 10 or high. In the above, if the temperature of the pack body 20 is less than 50°C, most of the resin cannot be melted and hardened, making spinning difficult, and if it exceeds 400°C, it is undesirable because the physical properties of the fibers are deteriorated due to rapid thermal decomposition of the resin. . At this time, the temperature of the pack body heater 10 may be controlled by an electric heater or a heat medium.

In the method of manufacturing a melt-spun nonwoven fabric of the present invention, during spinning, the fibers F pass through a nozzle-heating mantle 40 disposed directly under the spinning nozzle 32.

7 is an enlarged view of the nozzle heating unit 40 provided with the heater 41 for local heating of the nozzle directly under the nozzle of the present invention, wherein the spinning nozzle 32 is installed in the pack body 20 of the spinning device. , On the outside of the pack body 20, a pack body heater 10 is installed.

The present invention is a spinning nozzle 32 having a plurality of nozzle holes 31 forming fibers (F) by melt spinning a thermoplastic resin, and is disposed under the nozzle hole 31 of the spinning nozzle 32 to spin It includes a nozzle heating unit 40 for directly or indirectly heating the fiber F.

The heater holes 41a and 41b of the nozzle local heating heater 41, which are a feature of the present invention, are designed to be the same as the structure and number of the nozzle holes 31 of the spinning nozzle 32, so that the fibers discharged during spinning (F ) Is instantaneously heated at local high temperature while passing near the nozzle local heating heater 41.

FIG. 8 is a cross-sectional view taken along line Ⅰ-Ⅰ of FIG. 7, in which the embodiment of the hole type of the nozzle local heating heater 41 according to the present invention is a hole-type heater hole spaced within 1 to 300 mm from the center of the nozzle hole. And, by maintaining the structure of the nozzle hole 31 of the spinning nozzle 32, the inner circumferential surface is formed to be spaced within 1 to 300 mm from the center of the nozzle hole 31 of the spinning nozzle 32, It is characterized in that the temperature is maintained at the same distance in the direction of 360 degrees from the center of the nozzle hole 31 of (32).

In addition, the hole type of the nozzle local heating heater 41 is characterized in that when a plurality of hole layers are formed within the same radius of the nozzle hole, a nozzle heater is inserted between adjacent hole layers and hole layers.

The fiber (F) passed after spinning is passed through the heater hole (41a or 41b), so that it does not directly contact the heater hole (41a or 41b) when passing.

At this time, if the size of the heater hole (41a or 41b) is less than 1 mm from the center of the nozzle hole 31 of the spinning nozzle 32, the nozzle local heating heater 41 is likely to come into contact with the fiber (F). Highly high, contamination of the nozzle local heating heater 41 and fiber (F) trimming occur, resulting in poor fiber quality and workability. Also, there is a risk that the fiber (F) may be deteriorated due to excessive heat exposure, and exceeds 300 mm. In this case, since sufficient heat transfer to the fiber (F) is not possible, it is difficult to control the structure of the molecular chain entangled in the molten fiber polymer, and the effect of improving physical properties is lowered, which is not preferable.

At this time, the distance (a1) between the nozzle local heating heater 41 from the center of the nozzle hole 31 of the spinning nozzle 32 is preferably 1 mm or more and less than 50 mm. As the distance (a1) between the nozzle local heating heater 41 from the center of the nozzle hole 31 increases, it may be difficult to obtain an ultrafine fiber.

When the nozzle heating unit 40 provided directly under the nozzle of the present invention is described in detail, a spinning nozzle located at -50 (entering into the pack body) to 300 mm (outgressing out of the pack body) with respect to the lower part of the pack body 20 ( 32) The insertion depth (b2) of the nozzle local heating heater 41 that is in contact or partially inserted into the lower portion b1 and the lower portion of the radiating nozzle 32 is 0 to 50 mm, and the nozzle local heating heater ( The length of 41) is 5 to 500mm (b3), and the nozzle heating part 40 extends from the insertion depth (b2) of the nozzle local heating heater 41 partially inserted into the lower portion of the nozzle body, and the insertion depth. It is formed including the extended length (b3) of the heater 41 for the nozzle local heating.

In addition, the length of the nozzle local heating heater 41 is preferably 10mm or more to less than 300mm, preferably 50mm or more to 250mm.

At this time, as in the partially enlarged view of FIG. 7, a gap (b4) of 0 to 10 mm between the top surface of the nozzle local heating heater 41 inserted into the spinning nozzle 32 and the bottom surface of the spinning nozzle 32 opposite thereto. The heater 41 for local heating of the nozzle and the surface of the radiating nozzle 32 are directly in contact with each other (gap: 0mm) or are heated directly or indirectly (for example, conduction or radiation) with a gap (b4) of up to 10mm before radiation. The molten thermoplastic resin in the vicinity of the nozzle hole 31 in the spinneret 32 is first heated directly (eg, conduction).

Therefore, the nozzle heating unit 40, the melted thermoplastic resin in the vicinity of the nozzle hole 31 in the spinning nozzle 32 before spinning, of the nozzle local heating heater 41 inserted into the lower portion of the spinning nozzle 32. Direct (e.g., conduction) heating first by the insertion length (b2) and the gap (b4), and then by a heater 41 for local heating of a nozzle having a length of 5 to 500 mm (b3) from the insertion depth, after spinning The fiber (F) in the molten state before solidification discharged from the spinning nozzle 32 is secondarily heated (for example, radiation).

The above nozzle heating unit 40 directly transfers high-temperature heat to the vicinity of the nozzle hole 31 of the spinning nozzle 32 due to the structural change at the bottom of the spinning nozzle 32 that is actually commercialized, and The molecular chain entanglement structure in the molten polymer is controlled by instantaneous local high temperature heating by optimizing the fiber (F) indirectly by heating the fiber (F) indirectly by the nozzle for local heating 41 formed under it. By improving the stretchability of the obtained thermoplastic polymer fiber and delaying the cooling rate, it is possible to increase the spinning rate and improve productivity.

In addition, as shown in FIG. 10, the nozzle heating unit 40 provided directly under the nozzle of the present invention extends the spinning nozzle 32 from the lower surface of the nozzle body, and an additional extension distance z1 from the lower surface of the nozzle to the discharge port of the nozzle hole You can have.

When the lower surface of the spinning nozzle body is further extended, the heat of the nozzle heating unit can be transferred more intensively (efficiently) to the vicinity of the nozzle hole, improving the local heating effect, further reducing the nozzle shear pressure, and increasing the spinning speed. According to this, it is possible to maximize fineness.

In this case, a gap z2 through which air can pass may be formed between the nozzle hole 31 located in the additionally extended section and the nozzle hole adjacent thereto. In this case, heat can be uniformly transmitted to each nozzle hole, and in particular, local heating deviation between the outermost hole and the center hole can be minimized, thereby preventing the occurrence of denier and property deviation between nozzle holes.

The additional extension distance z1 of the lower surface of the nozzle body is 0 to 100 mm, preferably 1 to 50 mm, and the distance z2 between the extended sections may be 0 to 100 mm, preferably 1 to 10 mm. have.

In the manufacturing method of the present invention, since the lower structure of the spinning nozzle 32 that is actually commercialized can be changed and the nozzle heating unit 40 can be directly applied, the initial investment cost can be lowered, and the ultrafine fiber nonwoven fabric can be manufactured at low cost.

In the method of manufacturing a melt-spun nonwoven fabric of the present invention, in order to achieve fine fiber and improved productivity, the nozzle heating unit 40 is a retention of molten polymer passing through each nozzle hole 31 of the spinning nozzle 32. Optimization of time, flow rate and shear rate is required.

Accordingly, the preferred residence time of the molten polymer per hole is 5 seconds or less, the discharge amount per hole is at least 0.001 g/min.hole or more, and in terms of productivity and fineness of fibers, preferably 0.1 to 1 g/min, more preferably 0.3 to It is 0.7 g/min.

At this time, in the case of the polyester-based polymer, if the residence time exceeds 5 seconds, the molten polymer is exposed to excessive heat for a long time, resulting in a deterioration problem.If the discharge amount is less than 0.001 g/min, this also causes excessive heat to be exposed to the molten polymer. Deterioration problems may occur.

In addition, in the spinning nozzle 32, the shear rate of the wall of the nozzle hole 31 is preferably 1,000 to 200,000/sec, more preferably 5,000 to 50,000/sec, and at this time, the shear rate is 1,000/ If it is less than sec, the molecular orientation and structure control effect of the molten polymer due to low shear stress decreases, and if it exceeds 200,000/sec, melt fracture due to the viscoelastic properties of the molten polymer occurs, resulting in non-uniformity of the fiber cross section. As a result, there is a problem in that it is difficult to manufacture finely divided nonwoven fabrics.

In addition, the shear pressure at the nozzle is preferably maintained at 10 to 200 bar, and it is preferable to maintain 20 to 150 bar in order to maximize fiber fineness. If the shear pressure is less than 10bar, the deviation between the holes of the fiber denier becomes severe due to the difference in the discharge amount between the nozzle holes, and if it exceeds 200bar, excessive pressure may be applied to the nozzle, causing deformation or damage to the periphery.

In addition, the diameter (D) of the nozzle hole 31 of the spinning nozzle 32 was 0.01 to 1 mm in terms of fiber micro-fine. If the diameter of the nozzle hole is less than 0.01mm, there is a problem of clogging due to foreign matters during use and it is difficult to clean. If it exceeds 1mm, the spinning draft is high, so the fluctuation rate of the fiber cross-section becomes severe, and the fineness of the fiber is difficult.

In addition, the spinning nozzle 32 may include a fluid mixing device 50 in a flow path pipe above the hole.

That is, a fluid mixing device can be additionally provided inside the flow pipe above all nozzle holes constituting the spinning nozzle, and when the fluid mixing device is installed only in some holes, a difference in residence time and pressure between holes occurs, resulting in a quality problem. When installing a mixing device, it must be installed equally in all nozzle holes.

For example, a static mixer 50a may be used as the fluid mixing device 50. Static Mixer is a mixing device that can mix fluids using several curved screw blades. It is a convenient and economical to mix fluids continuously and uniformly just by passing through the pipe without a rotating part or special power. With the phosphorus mixing device, in particular, it is possible to obtain the effect of easily exchanging heat exchange between the outside and the inside of the nozzle hole.

The shape of the static mixer is not particularly limited as long as it has a shape suitable for dispersion in the nozzle, but when considering the degree of mixing, it is preferably a screw shape or a spiral shape. In addition, the static mixer may be included in a form in which a plurality of the nozzles are installed in various directions. The static mixer may be made of a known material without any particular limitation, and may be manufactured by a method of manufacturing a mold or a mold using, for example, a metallic material.

As another example, by using a metal powder, a metal foam, and a porous metal filter 50b as the fluid mixing device, the same effect as that of a static mixer can be expected.

In addition, the ratio (L/D) of the length (L) and the diameter of the nozzle hole 31 was set to 2 to 10. If the ratio (L/D) of the hole length and the hole diameter of the spinning nozzle is less than 2, external heat cannot be sufficiently transferred directly to the molten resin flowing in the hole, making it difficult to microfine fibers, and if the ratio (L/D) exceeds 10, the inside of the hole Excessive heat was directly transferred to the flowing molten resin, resulting in poor fiber properties and increased pack pressure, resulting in poor spinnability.

In addition, the number of holes 31 in the nozzle body is 1 or more, the pitch between the nozzle holes 31 is 0.1 mm or more, and the cross section of the nozzle hole 31 is illustrated in a circular shape in the embodiment of the present invention. It is not limited, and a modified cross section (Y, +, -, O, etc.) may also be applied. In addition, through a spinneret including the spinning nozzle 32, two or more types of composite spinning, such as a cis-core type, a side-by-side type, and a sea-island type, will be possible.

Since the number of the hole-type heater holes 41a of the nozzle localized heating heater 41 of the present invention is the same as the structure of the nozzle hole 31 of the spinning nozzle 32, the circular, elliptical, square, donut-shaped It includes all types of hole structures, such as.

In addition, the heater for local heating of the nozzle 41 can be applied as a conventional electric heating wire, and examples thereof include Cu-based and Al-based casting heaters, electromagnetic induction induction heaters, sheath heaters, flange heaters, and cartridges. (cartridge) heater, coil heater, near-infrared heater, carbon heater, ceramic heater, PTC heater, quartz tube heater, halogen heater, nichrome wire heater, optical heater such as laser, ultrasonic heater, etc. I can.

The raw material polymer that can be used in the method for producing the melt-spun nonwoven fabric of the present invention may be employed without limitation among general-purpose thermoplastic polymers, but more preferably polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytri A polyester-based polymer selected from the group consisting of methylene terephthalate (PTT), polycyclohexanedimethanol terephthalate (PCT), polyethylene naphthalate (PEN), and polyarylate; Polyamide polymer selected from nylon 6, nylon 6,6, nylon 4 and nylon 4,6; Or a polyolefin-based polymer selected from polyethylene or polypropylene; Any one selected from polyphenyl sulfite (PPS) may be used alone or in a mixture of two or more.

In the embodiment of the present invention, polypropylene and polyethylene terephthalate (PET) are described as preferred examples, but the present invention will not be limited thereto.

The manufacturing method of the melt-spun nonwoven fabric of the present invention is characterized in that it is a manufacturing method by an open type or a closed type spunbond method.

As described above, the method of manufacturing the melt-spun nonwoven fabric of the present invention uses a high-speed air flow performed by the conventional open and closed spun-bond methods after the melt-spun fibers are instantaneously localized by high temperature heating. The same applies to the method of collecting and winding fibers on a conveyor belt.

That is, the present invention introduces an instantaneous local high-temperature heating method of direct or indirect instantaneous heating of fibers in the vicinity of the hole of the spinning nozzle and directly under the spinning nozzle in the melt spinning process, so that the melt viscosity and radiation of the thermoplastic resin discharged from the nozzle hole without reducing the molecular weight. By lowering the elongation viscosity, it is possible to provide a nonwoven web of ultrafine fibers capable of fine fibers compared to the conventional spunbond nonwoven fabric.

Therefore, by using the conventional open-type and closed-type spun-bond manufacturing process as it is, the initial investment cost is low, and it is possible to mass-produce high value-added, high-functional ultrafine fiber nonwovens at low cost.

In addition, by optimizing the melt-spinning step of the fiber with an instant local high-temperature heating method, the molecular weight is controlled and the spinning, heat treatment conditions are controlled, and various fiber structures (strength, elongation, elastic modulus, etc.), fineness, and composite yarns It is possible to manufacture ultrafine fiber nonwoven fabric having a cross-sectional shape (deformed cross-section) (sea-sea yarn, ciscoa, side-by-side, etc.).

In particular, from the method of manufacturing the melt-spinning nonwoven fabric of the present invention, the melt viscosity of the thermoplastic resin discharged from the nozzle hole is lowered without lowering the molecular weight of the resin of high viscosity, which was difficult in the conventional spunbond method, thereby lowering the pressure of the spinning nozzle and elongation in radiation. By lowering the viscosity, the fiber tension between the spinning nozzle and the ejector is lowered, thereby providing a microfiber nonwoven web capable of fine fiber using a resin having a high viscosity compared to the conventional open and closed spunbond methods.

In addition, the manufacturing method of the melt-spun nonwoven fabric of the present invention is to satisfy the same denier (denier) and physical properties as the nonwoven fabric manufactured from the conventional spun-bond manufacturing process, the molten state fibers discharged from the spinning nozzle. As the spinning speed increases due to local heating passing through each of the heating holes, the discharge amount of the initial thermoplastic polymer can be increased, so that the productivity of the nonwoven fabric can be improved.

Thus, the present invention is a polypropylene (PP) polymer having a melt viscosity (MFI) of 3 to 900, preferably 3 to 300, more preferably 3 to 100 from the method of manufacturing the melt-spun nonwoven fabric is localized at the moment of spinning It provides a microfine fiber nonwoven fabric web fine-finished by high-temperature heating treatment.

In particular, the method of manufacturing a melt-spun nonwoven fabric of the present invention provides an ultrafine fiber nonwoven web by lowering the pack pressure to an extent capable of spinning a high-viscosity thermoplastic polymer by instantaneously local high temperature heating treatment of the melt-spun fibers.

In an embodiment of the present invention, polypropylene (PP) polymer having melt viscosity (MFI) of 10 and 28 is subjected to instantaneous local high temperature heating treatment when spinning, and polypropylene having a relatively high viscosity of melt viscosity (MFI) of 10 (PP) In the case of a polymer, it is spun and provides a fine fiber nonwoven web. At this time, the PP resin and fiber melt viscosity (MFI, Melt Flow Index) measurement method is obtained according to ASTM D1238 (MFI 230/2) method, specifically, after melting the resin for about 6 minutes at 230 ℃, a nozzle having a diameter of 2mm Measure the weight (g/10min) of the resin discharged for 10 minutes by applying pressure with a weight of 2.16kg.

At this time, the ejector 204 of the spunbond method is to provide a high-speed air stream for stretching the discharged fiber yarn, and when the fiber yarn discharged from the spinneret is spun It is preferable that the distance from the ejector to the compressed air outlet is 100 to 2000 mm. If it is less than 100mm, fineness and threading tend to occur as it enters the ejector with insufficient cooling of the fiber.If it exceeds 2000mm, the resistance of sufficiently solidified fiber and air before the ejector increases, resulting in fineness. There may be a difficult problem. It is presumed that this is because a stretching tension can be applied to a position in which cooling and solidification is not completely completed by the position of the ejector in the spinning yarn, and thus orientation crystallization can be promoted along with the fineness of the fibers.

In addition, various shapes such as round and rectangular are known as the shape of the ejector 204, but in order to efficiently use the air consumption of high-pressure air jets without fusion or interference between threads, the shape of the detention and the shape of the ejector are Similar combinations are preferred. For example, if it is a circular nozzle, a circular ejector is preferable, and if it is a rectangular nozzle, a rectangular ejector shape is preferable.

Thus, by the instantaneous local high temperature heating method directly under the nozzle during melt spinning of the present invention, a relatively low melt viscosity (MFI) that could not be obtained from the existing melt viscosity (MFI) of each fiber targets a polyolefin-based fiber group having various melt viscosity (MFI). Polyolefin-based fibers having a fineness of denier can be provided.

At this time, the fineness in the microfiber nonwoven web satisfies the fineness or less calculated by the following Equation 1.

Equation 1

Fineness (㎛) = 94 × A ^(-0.71)

In the above, A is the melt viscosity of the fibers constituting the spunbond nonwoven fabric when using pure polypropylene (PP) polymer without additives or modifier components.

In addition, the present invention is a polyethylene terephthalate (PET) polymer having an intrinsic viscosity (IV) of 0.5 to 3.0 measured according to ASTM D4603-3 method from the manufacturing method of the melt-spun nonwoven fabric described above by local high temperature heating treatment at the time of spinning. It provides a fine fiber nonwoven web.

At this time, the fineness in the ultrafine fiber nonwoven web satisfies the fineness or less calculated by the following Equation 2 below.

Equation 2

Fineness (㎛) = (34 × B)-12.7

In the above, B is the intrinsic viscosity of the fibers constituting the spunbond nonwoven fabric when using pure polyethylene terephthalate (PET) polymer without additives or modifier components.

Furthermore, the present invention can be used without limitation in conventional nonwoven fabric uses including microfiber nonwoven fabric web from the above manufacturing method, but more preferably, it is useful for filter materials or sanitary materials including microfiber nonwoven fabric web of the present invention, and the sanitary Ash includes general purpose feminine and infant disposable hygiene products or mask packs.

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

The present examples are for explaining the present invention in more detail, and the scope of the present invention is not limited to these examples.

[How to measure]

-Melt viscosity (MFI) (g/10min)

MFI of PP was measured under the conditions of a measurement temperature of 230°C and a measurement load of 2.16 kg according to ASTM D1238.

-Intrinsic viscosity (I.V.) (dl/g)

The I.V. of PET was measured at 30°C in 60/40% by weight phenol/tetrachloroethane according to ASTM D4603-3 method.

-Draft

The draft value was calculated based on the following equation.

Fiber speed at ejector (spinning speed) / Fiber discharge speed at nozzle outlet

-Spinning speed (m/min)

The spinning speed V was calculated based on the following equation from the average density of the fibers and the discharge amount D (hereinafter abbreviated as the single hole discharge amount) (g/min) of the resin discharged from the spinneret single hole set under each condition.

Spinning speed (m/min) = (9000(m) × D (g/min)) / denier

-Strength (MPa) and elongation (%)

According to ASTM D 885 test method, a 300 m/min tensile speed was applied to a sample length of 250 mm at a temperature of 25°C and 65% relative humidity using an Instron Testing Machine (Instron Engineering Corp., Canton, Mass). By doing so, the tensile strength and elongation of the mixed fiber were measured.

1. Manufacture of polypropylene microfiber nonwoven fabric

< Example 1> Manufacture of ultrafine fiber nonwoven fabric

Polypropylene (PP) resin having a melt viscosity (MFI) of 28 is put into an extruder, melt-extruded, and flowed into a spinning nozzle, and during spinning, instantaneous local high-temperature heating is performed by a heater for local heating of the nozzle disposed directly under the nozzle as shown in FIG. Polypropylene-based microfiber nonwoven fabric was prepared by performing according to the following spinning conditions.

(1) Radiation conditions

-Extruder temperature: 240℃

-Radiation pack temperature: 240℃

-Discharge per hole of spinning nozzle: 0.35g/minㆍhole

-Ejector air pressure: 250kPa

-Number of spinning nozzle holes (in the nozzle): 24

-Temperature of the heater for local heating of the nozzle: +50℃ or higher compared to the temperature of the pack body

-Heater hole of a heater for nozzle local heating: A hole type spaced within 5mm from the center of the nozzle hole

< Example 2>

A polypropylene-based microfiber nonwoven fabric was prepared in the same manner as in Example 1, except that the ejector pressure was performed at 350 kPa.

< Example 3>

A polypropylene-based microfiber nonwoven fabric was prepared in the same manner as in Example 1, except that the discharge amount per hole of the spinning nozzle was performed at 0.40 g/min·hole.

< Example 4>

Except for using a high-viscosity polypropylene (PP) resin having a melt viscosity (MFI) of 10, a polypropylene-based microfiber nonwoven fabric was prepared in the same manner as in Example 1 above.

< Example 5>

As shown in Fig. 10, the embodiment 1, except that the additional extension distance (Z1) of the lower surface of the nozzle is 30 mm, the gap z2 between the holes is 3 mm, and the ejector pressure is 350 kPa. In the same manner as, a polypropylene-based microfiber nonwoven fabric was prepared.

< Example 6>

In Example 5, a polypropylene-based microfiber nonwoven fabric was manufactured in the same manner as in Example 5, except that a static mixer in the nozzle passage pipe was used.

< Comparative example 1>

When spinning in Example 1, a polypropylene-based ultrafine fiber nonwoven fabric was carried out in the same manner as in Example 1, except that a spinning nozzle without a heater for local heating of the nozzle disposed directly under the nozzle as shown in FIG. 5 was used. Was prepared.

< Comparative example 2>

When spinning in Comparative Example 1, it was performed in the same manner as in Comparative Example 1, except that the ejector pressure was performed at 350 kPa.

< Comparative example 3>

When spinning in Comparative Example 1, it was carried out in the same manner as in Example 1, except that a polypropylene (PP) resin having a melt viscosity (MFI) of 10 was used.

< Experimental example 1>

Preparation of the nonwoven fabrics performed in Examples 1 to 4 and Comparative Examples 1 to 3 and physical properties thereof are shown in Table 1 below.

Polypropylene fiber
Non-woven fabric manufacturing Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 driving
Condition Melt viscosity (MFI) 28 28 28 10 28 28 28 28 10 Heater for local heating under the nozzle ○ ○ ○ ○ ○ ○ X X X Using Static Mixer X X X X X ○ X X X Distance between heaters from the center of nozzle hole (a1), mm 5 5 5 5 5 5 - - - Heating heater length (b3), mm 50 50 50 50 50 50 - - - Additional extension distance on the bottom of the nozzle (z1), mm 0 0 0 0 30 30 - - - Distance between holes between extension sections (z2), mm 0 0 0 0 3 3 - - - Discharge volume, g/min.hole 0.35 0.35 0.40 0.35 0.35 0.35 0.35 0.35 0.35 Ejector pressure, kPa 250 350 250 250 350 350 250 350 250 fair
Actual Survey
value


Nozzle shear pressure, bar 38 38 46 112 31 42 72 72 203 Shear rate
sec ^-1 8250 8250 9425 8250 8250 8250 8250 8250 8250 Draft ^{1 )} 318 391 252 88 431 424 242 - - Spinning speed ^{2 )} m/min 3940 4840 3560 1085 5340 5250 3000 - - Spun-bond Fibers
Properties Diameter, um 10.8 9.7 12.1 20.5 9.2 9.3 12.3 - - Fineness ^{3 )} 0.80 0.65 1.01 2.90 0.59 0.60 1.05 - - Strength, MPa 203 237 195 270 225 229 211 - - Elongation,% 162 154 173 180 158 164 160 - - Melt viscosity, MFI 31 31 30 11 30 29 30 - - Web production, g/min 8.3 8.4 9.6 8.4 8.3 8.3 8.4 - -

¹⁾ Draft = fiber speed at ejector (spinning speed)/fiber discharge speed at nozzle exit

²⁾ Spinning speed (m/min): Calculated based on the calculated fineness value and discharge amount

³⁾ Fineness (denier): Calculated in consideration of the measured value of diameter (um) and the weight of yarn 0.98

From the results of Table 1, compared to Comparative Example 1, Example 1 reduced the nozzle shear pressure, increased spinning speed and reduced fineness, enabling fineness, but was similar in physical properties and molecular weight of fibers, so that thermal decomposition by high-temperature local heating did not occur. I was able to confirm that it did not.

In Example 2, high-speed spinning was possible, which was not possible in Comparative Example 2, and additional fineness was possible by increasing the spinning speed compared to Example 1, and the physical properties and molecular weight of the fiber were improved or similar, resulting in thermal decomposition due to high-temperature local heating. I was able to confirm that it did not work.

In addition, in Example 3, compared to Comparative Example 1, it was confirmed that fibers having similar fineness and physical properties could be produced at a higher spinning speed, and productivity increased by increasing web production per unit time.

In Example 4, compared to Comparative Example 3, it was confirmed that a resin having a high viscosity (high molecular weight, low MFI) can be spun.

Example 5, compared to Example 2, can improve the local heating effect as the nozzle shear pressure is further reduced, and at the same time, increase the spinning speed to maximize fineness, and it can be confirmed that the physical properties and molecular weight of the fiber are similar. there was.

In Example 6, compared to Example 5, it was confirmed that the nozzle shear pressure was increased due to the occurrence of resistance in the flow path according to the application of the static mixer, the spinning speed and fineness were similar, and the decrease in the molecular weight of the fiber was improved.

In addition, in Comparative Example 2 and Comparative Example 3, spinning was not possible.

As a result, it was confirmed that the microfine fiber nonwoven fabric prepared by the method of Examples 1 to 6 was manufactured without deterioration in mechanical properties such as toughness and ductility, and there was no change in melt viscosity as well as fine fiber fineness. Could.

2. Polyethylene terephthalate (PET) Manufacture of ultrafine fiber nonwoven fabric

< Example 7> Manufacture of ultrafine fiber nonwoven fabric

Polyethylene terephthalate (PET) with intrinsic viscosity (IV) 0.65 The resin is put into an extruder, melted, extruded, and introduced into a spinning nozzle, and when spinning, it is subjected to instant local high temperature heating by a heater for local heating of the nozzle disposed directly under the nozzle as shown in FIG. 7 and carried out according to the spinning conditions below to perform polypropylene ultrafine. A fibrous nonwoven fabric was prepared.

(1) Radiation conditions

-Extruder temperature: 290℃

-Radiation pack temperature: 290℃

-Discharge amount per hole of spinning nozzle: 0.40g/minㆍhole

-Ejector air pressure: 300 kPa (3 bar)

-Number of spinning nozzle holes (in the nozzle): 24

-Temperature of the heater for local heating of the nozzle: +50℃ or higher compared to the temperature of the pack body

-Heater hole of a heater for nozzle local heating: A hole type spaced within 5mm from the center of the nozzle hole

< Example 8>

A polyethylene terephthalate-based microfiber nonwoven fabric was prepared in the same manner as in Example 7, except that the ejector pressure was performed at 400 kPa.

< Example 9>

A polyethylene terephthalate-based ultrafine fiber nonwoven fabric was prepared in the same manner as in Example 7, except that the discharge amount per hole of the spinning nozzle was performed at 0.46 g/min·hole.

< Example 10>

A polyethylene terephthalate-based ultrafine fiber nonwoven fabric was prepared in the same manner as in Example 7, except that a high viscosity polyethylene terephthalate (PET) resin having an intrinsic viscosity (IV) of 1.20 was used.

< Example 11>

As shown in FIG. 10, the above embodiment 7 except that the additional extension distance (Z1) of the lower surface of the nozzle was set to 30 mm, the gap between the holes (z2) between the extended sections was set to 3 mm, and the ejector pressure was set to 400 kPa. In the same manner as, a polyethylene terephthalate-based ultrafine fiber nonwoven fabric was prepared.

< Example 12>

In Example 11, a polyethylene terephthalate-based ultrafine fiber nonwoven fabric was manufactured in the same manner as in Example 11, except that a static mixer in the nozzle passage pipe was used.

< Comparative example 4>

When spinning in Example 7, polyethylene terephthalate-based ultrafine fibers were carried out in the same manner as in Example 7, except that a spinning nozzle without a heater for local heating of the nozzle disposed directly under the nozzle as shown in FIG. 5 was used. A nonwoven fabric was prepared.

< Comparative example 5>

When spinning in Comparative Example 4, it was performed in the same manner as in Comparative Example 4, except that the ejector pressure was performed at 400 kPa.

< Comparative example 6>

When spinning in Comparative Example 4, it was performed in the same manner as in Comparative Example 4, except that polyethylene terephthalide (PET) resin having an intrinsic viscosity (IV) of 1.2 was used.

< Experimental example 2>

Preparation of the nonwoven fabrics performed in Examples 7 to 12 and Comparative Examples 4 to 6 and physical properties thereof are shown in Table 2 below.

Item
PET Example Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Comparative Example 4 Comparative Example 5 Comparative Example 6 driving
Condition Intrinsic viscosity, I.V. 0.65 0.65 0.65 1.20 0.65 0.65 0.65 0.65 1.20 Heater for local heating under the nozzle ○ ○ ○ ○ ○ ○ X X X Using Static Mixer X X X X X ○ X X X Distance between heaters from the center of nozzle hole (a1), mm 5 5 5 5 5 5 - - - Heating heater length (b3), mm 50 50 50 50 50 50 - - - Additional extension distance on the bottom of the nozzle (z1), mm 0 0 0 0 30 30 - - - Distance between holes between extension sections (z2), mm - - - - 3 3 - - - Discharge volume, g/min.hole 0.40 0.40 0.46 0.40 0.40 0.40 0.40 0.40 0.40 Ejector pressure, kPa 300 400 300 300 400 400 300 400 300 Process measurement
value


Nozzle shear pressure, bar 48 48 58 127 39 50 86 86 215 Shear rate
sec-1 7200 7200 8270 7200 7200 7200 7200 - - Draft ^{1 )} 359 513 318 104 585 575 312 - - Spinning speed ^{2 )} m/min 3870 5540 3940 1125 6320 6210 3365 - - Properties of Spun-bond Fibers Diameter, um 9.8 8.2 10.4 18.1 7.7 7.7 10.5 - - Fineness ^{3 )} 0.93 0.65 1.05 3.20 0.57 0.58 1.07 - - Strength, MPa 315 330 319 360 335 333 324 - - Elongation,% 106 102 120 94 98 103 113 - - Intrinsic viscosity, I.V. 0.60 0.61 0.61 0.91 0.61 0.62 0.61 - - Web production, g/min 9.6 9.5 11.5 9.6 9.6 9.6 9.6 - -

¹⁾ Draft = fiber speed at ejector (spinning speed)/fiber discharge speed at nozzle exit

²⁾ Spinning speed (m/min): Calculated based on the calculated fineness value and discharge amount

³⁾ Fineness (denier): Calculated in consideration of the measured value of diameter (um) and the weight of yarn 0.98

From the results of Table 2, Example 7 and Comparative Example 4 compared the physical properties according to the presence or absence of the heater for local heating of the nozzle disposed directly under the nozzle under the same radiation condition, Example 7 reduced nozzle shear pressure, spinning speed It was confirmed that fineness was possible by increasing and decreasing fineness, and thermal decomposition by high temperature local heating did not occur, so that the physical properties and molecular weight of the fiber were similar.

In addition, Example 8 was carried out by raising the air pressure of the ejector under the same conditions, a finer non-woven fabric of ultra-fine (8.2㎛) fibers was obtained.

In addition, it was confirmed through Example 9 that in the case of increasing the discharge amount from the nozzle in order to produce the same fineness, the web output rate of the nonwoven fabric can be increased. At this time, the ultrafine fiber nonwoven fabric of the present invention was maintained without deterioration in physical properties and intrinsic viscosity of the fiber.

In addition, in Example 10, it was confirmed that a high-viscosity resin that could not be spun in Comparative Example 3 could also be spun.

In Example 11, compared to Example 2, the nozzle shear pressure was further reduced, the local heating effect was improved, and fineness was maximized by increasing the spinning speed.

In Example 12, compared to Example 5, it was confirmed that the nozzle shear pressure increased due to resistance generation in the flow path due to the application of the static mixer, the spinning speed and fineness were similar, and the decrease in the molecular weight of the fiber was improved.

In Comparative Example 5 and Comparative Example 6, spinning was not possible.

As a result, it was confirmed that the microfiber nonwoven fabric prepared by the method of Examples 7 to 12 was produced without deterioration in mechanical properties such as toughness and ductility because there was no change in melt viscosity as well as fine fiber fineness. Could.

In the above, the present invention has been described in detail only with respect to the described embodiments, but it is obvious to those skilled in the art that various modifications and modifications are possible within the scope of the present invention, and it is natural that such modifications and modifications fall within the scope of the appended claims.

10: pack body heater 20: pack body
30: molten polymer resin 31: nozzle hole
32: spinning nozzle 40: nozzle heating unit
41: nozzle local heating heater 41a, 41b: heater hole
50: fluid mixing device
100, 200, 300, 400: hopper 101, 201, 301, 401: extruder
102, 202, 302, 402: gear pump 103, 203, 303, 403: nozzle
104: roller 204: ejector
304: duct 404: melt blown die
105, 205, 305, 405: winding portion

Claims (11)

In the method of manufacturing a nonwoven fabric by a melt-spinning spunbond method in which fibers melt-spun through a spinning nozzle in which a thermoplastic polymer has at least one nozzle hole is collected with a high-speed air stream,
When the melt-spun fiber is spun, it passes through the nozzle heating part provided directly under the spinning nozzle, and the temperature difference compared to the pack body temperature is instantaneously subjected to local high-temperature heating at a temperature of 0.1 to 1,000°C,
The discharge amount of the nozzle hole is 0.001 to 1 g/min.hole,
The diameter of the nozzle hole is 0.01 to 1 mm,
The method of manufacturing a finely divided melt-spun nonwoven fabric, characterized in that the ratio of the length and diameter of the nozzle hole is 2 to 10. The method of claim 1, wherein the nozzle local heating heater is formed in a number corresponding to at least one nozzle hole hole-type heater hole spaced within 1 to 300 mm from the center of the nozzle hole. Method for producing a melt-spun nonwoven fabric. The method according to claim 2, wherein the nozzle local heating heater is formed in a belt-shaped type inserted between adjacent hole layers and hole layers, when a plurality of hole layers are formed within the same radius of the nozzle hole, from the center of each nozzle hole. A method of manufacturing a finely divided melt-spinning nonwoven fabric, characterized in that a strip-shaped heater hole arranged in a row within 300 mm is formed. The method of claim 1, wherein the thermoplastic polymer is polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polycyclohexanedimethanol terephthalate (PCT), polyethylene naphthalate ( PEN) and a polyester-based polymer selected from the group consisting of polyarylate; Polyamide polymer selected from nylon 6, nylon 6,6, nylon 4 and nylon 4,6; Or a polyolefin-based polymer selected from polyethylene or polypropylene; Polyphenylsulfite (PPS); Method for producing a finely divided melt-spun nonwoven fabric, characterized in that it is a single or a mixture of two or more selected from. The method of claim 1, wherein the nozzle heating unit contacts or partially inserts a lower portion of the spinneret located at -50 (enters into the pack body) to 300mm (outside the pack body) with respect to the lower portion of the pack body, and under the spinneret. The nozzle local heating heater has an insertion depth of 0 to 50 mm, the nozzle local heating heater has a length of 5 to 500 mm, and the nozzle heating unit is the insertion depth of the nozzle local heating heater partially inserted into the lower part of the nozzle body. And a method of manufacturing a finely divided melt-spinning nonwoven fabric, characterized in that it is formed including an extension length of the nozzle local heating heater extending from the insertion depth. The method of claim 5, wherein the additional extension distance of the lower surface of the nozzle body is 0 to 100 mm, and the distance between the extended sections is 0 to 100 mm. The method of claim 1, wherein the spinning nozzle comprises a fluid mixing device in a flow path pipe above the hole. From the manufacturing method of any one of claims 1 to 7, a polypropylene (PP) polymer having a melt viscosity (MFI) of 3 to 900 is fine-finished by a local high temperature heating treatment at the time of spinning. The ultrafine fiber nonwoven web according to claim 8, wherein the fineness has a fineness less than or equal to the fineness calculated by the following formula (1).
Equation 1
Fineness (㎛) = 94 × A ^(-0.71)
In the above, A is the melt viscosity of the fibers constituting the spunbond nonwoven fabric when using pure polypropylene (PP) polymer without additives or modifier components. From the manufacturing method of any one of claims 1 to 7, a polyethylene terephthalate (PET) polymer having an intrinsic viscosity (I.V.) of 0.5 to 3.0 is finely made by local high temperature heating treatment at the time of spinning. The ultrafine fiber nonwoven web of claim 10, wherein the fineness has a fineness less than or equal to the fineness calculated by the following equation (2).
Equation 2
Fineness (㎛) = (34 × B)-12.7
In the above, B is the intrinsic viscosity of the fibers constituting the spunbond nonwoven fabric when using pure polyethylene terephthalate (PET) polymer without additives or modifier components.

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