KR102542382B1 - Apparatus of manufacturing drying type separator using inline process - Google Patents

Abstract

We propose a dry separation membrane manufacturing device using a continuous process that increases yield, makes quality uniform, reduces time and manpower due to discontinuous processes to the maximum, and eliminates bottlenecks. The device includes an unstretched sheet production unit, an annealing unit where unstretched sheets are continuously fed without delay, and a stretching unit where annealed unstretched sheets are continuously fed without delay, and the unstretched sheet production unit supplies molten polymer resin to a discharge sheet. A discharge sheet using an extrusion die for discharging, a tension control roller disposed apart from the extrusion die by a third distance D3, and an air nozzle disposed between the extrusion die and the tension control roller and injecting cooling gas to the discharge sheet. and an air knife for cooling and converting the unstretched sheet into an unstretched sheet, and the tension control roller controls the tension applied to the ejection sheet and the unstretched sheet.

Description

Dry type separator manufacturing apparatus using continuous process {Apparatus of manufacturing drying type separator using inline process}

The present invention relates to a separator manufacturing apparatus, and more particularly, to an apparatus for efficiently manufacturing a dry separator used in a battery by continuously performing manufacturing processes such as forming an unstretched sheet, annealing, and stretching.

A separator for a battery serves to prevent electrical contact by separating the positive and negative electrodes of a battery, and the separator has fine pores. In the battery, electricity is generated by moving ions between the positive electrode and the negative electrode through the pores. The separation membrane is largely manufactured by a dry process and a wet process. Among them, the dry process for controlling the crystal structure is a method of manufacturing a separator by extruding a molten polymer resin to prepare an unstretched sheet, adjusting the crystal structure by annealing, and forming pores by stretching. The separation membrane manufactured by the dry process is eco-friendly because it does not use an extraction solvent, and has a high price competitiveness because the production process is simple.

Conventional dry separation membranes are manufactured by discontinuously performing processes such as extrusion, casting, heat treatment (annealing), and stretching, as in Korean Patent Registration No. 10-0928898. In the discontinuous process, after manufacturing an unstretched sheet by extrusion and casting, the unstretched sheet is transferred to an annealing process to perform a high-temperature heat treatment, and then the annealed unstretched sheet is moved to a stretching process to perform a stretching process. do. Discontinuous processes cause loss of separators for each process, and it is difficult to obtain uniform quality in the entire process. In addition, since it moves to each process, it takes time and manpower required for movement.

In general, a conventional separator utilizes a casting roll to manufacture an unstretched sheet. 1 is a schematic diagram for explaining a process of manufacturing a conventional unstretched sheet using a casting roll. According to FIG. 1, the molten resin supplied from the extruder 100 is cooled and solidified while the discharge sheet Fo discharged through the extrusion die 101 is brought into contact with the relatively low temperature casting roll 102 to form lamellar crystals. An unstretched sheet (Fs) is produced. If necessary, cooling gas may be supplied to the casting roll 102 through the gas supply unit 103 to adjust the lamellar crystal structure. In order to apply the conventional casting roll 102 to a continuous process while considering the lamellar crystal structure, it is difficult to coordinate the casting speed passing through the discharge sheet Fo to the casting roll 102 with the annealing speed. The reason why manufacturing and annealing of the unstretched sheet Fs are discontinuously occurs is that a bottleneck phenomenon inevitably occurs in the casting roll 102 and the annealing process section.

The problem to be solved by the present invention is to provide a dry separation membrane manufacturing apparatus using a continuous process in which the yield is increased, the quality is uniform, the time and manpower due to the discontinuous process is reduced to the maximum, and the bottleneck is eliminated.

Dry type separation membrane manufacturing apparatus using a continuous process for solving the problems of the present invention is an unstretched sheet manufacturing unit, an annealing unit in which the unstretched sheet is continuously input without delay, and the annealed unstretched sheet is continuously input without delay It includes a stretching part. At this time, the unstretched sheet manufacturing unit is between an extrusion die for discharging the molten polymer resin into a discharge sheet, a tension control roller disposed apart from the extrusion die by a third distance D3, and the extrusion die and the tension control roller. and an air knife for cooling the discharge sheet and converting it into the unstretched sheet by using an air nozzle for injecting a cooling gas into the discharge sheet. Here, the tension control roller controls the tension applied to the discharge sheet and the unstretched sheet.

In the apparatus of the present invention, the air knife is disposed on one side or both sides of the discharge sheet. The third distance D3 is preferably 50 mm to 150 mm. The air knife becomes narrower toward the air nozzle. The air injection hole forms a first distance D1 from the extrusion die and a second distance D2 from the discharge sheet, the first distance D1 is 5 mm to 70 mm, and the second distance D2 Silver is preferably 10 mm to 50 mm. The wind speed of the cooling gas sprayed from the air nozzle is preferably 10 m/s to 100 m/s. When the air knives are disposed on both sides, the air jetting holes form first and second jetting angles θ1 and θ2 with respect to the discharge sheet, and the first and second jetting angles θ1 and θ2 are 40 It may be from 90 degrees to 90 degrees. The first and second spraying angles θ1 and θ2 may be different from each other. A heating unit may be installed in the nozzle of the extrusion die. The molding speed of the unstretched sheet is preferably 1 m/m to 40 m/m.

In a preferred device of the present invention, the annealing unit includes an oven for supplying thermal energy, a plurality of conveying rollers, and a tenter clip chain, and the tenter clip chain is bound to the plurality of conveying rollers and moves according to the rotation of the conveying rollers. The unstretched sheet is fixed. As for the plurality of conveying rollers, there are a plurality of a pair of conveying roller sets in which the unstretched sheet forms a unit length. The process length by the annealing unit may be determined according to the number of sets, the unit length, and the distance between the sets.

According to the dry type separator manufacturing apparatus using the continuous process of the present invention, by excluding the casting roll and cooling the unstretched sheet with an air knife, the yield is increased, the quality is uniform, and the time and Manpower is reduced as much as possible and bottlenecks are eliminated.

1 is a schematic diagram for explaining a process of manufacturing a conventional unstretched sheet.
2 is a flowchart showing a method of manufacturing a separator for a battery according to the present invention.
Figure 3 is a view for explaining the extrusion and molding apparatus applied to the manufacturing apparatus according to the present invention.
4 is a view for explaining an annealing apparatus applied to a manufacturing apparatus according to the present invention.
5 to 8 are enlarged photographs of separation membranes according to experimental examples of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below may be modified in many different forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. In the drawings, it is exaggeratedly expressed for convenience of explanation. On the other hand, terms indicating positions such as top, bottom, front, etc. are only related to those shown in the drawings. In practice, the fabrication device can be used in any selective orientation, and in actual use, the spatial orientation changes depending on the orientation and rotation of the fabrication device.

Embodiments of the present invention exclude casting rolls and cool unstretched sheets with air knives, thereby increasing yield, uniform quality, and maximally reducing time and manpower due to discontinuous processes and bottlenecks A dry separation membrane manufacturing apparatus using a continuous process in which this is removed is presented. To this end, a dry separation membrane manufacturing apparatus equipped with an air knife will be examined in detail, and a method for manufacturing a separation membrane using the manufacturing apparatus will be described in detail. The separator of the present invention is manufactured by a dry process. That is, it can be applied to a particle stretching process in which an extraction solvent is not used, but in some cases, particles forming pores are added.

2 is a flowchart showing a method of manufacturing a separator for a battery according to an embodiment of the present invention. However, it is not a drawing in a strict sense, and there may be components not shown in the drawing for convenience of description.

According to FIG. 2, the manufacturing method of the present invention first extrudes and molds a polymer resin to produce an unstretched sheet (S10). At this time, the polymer resin is preferably semi-crystalline, and examples thereof include polyolefins, polyfluorocarbons, polyamides, polyesters, polyacetals, polysulfides, polyvinyl alcohols, copolymers thereof, and the like. It may be a polymer compound selected from the group consisting of combinations. The polymer resin is preferably a polyolefin resin, and the polyolefin resin is, for example, a homopolymer of olefins such as polypropylene, high density polyethylene, low density polyethylene, low density polyethylene, polybutene, polystyrene, etc., or an ethylene-propylene copolymer, ethylene-butylene It may be a copolymer of olefins such as a copolymer, a propylene-butene copolymer, or a mixture thereof.

In addition, when extruding the polymer resin, a reinforcing agent, a filler, an antioxidant, a surfactant, a neutralizer, a heat stabilizer, a weathering stabilizer, an antistatic agent, a lubricant, a slip agent, a pigment, and a nucleating agent within a range that does not interfere with the operation of the battery. Various additives such as may be added. The additive is not particularly limited as long as it is a material known in the art. Among these additives, it is more preferable to add an antioxidant to secure long-term heat resistance and oxidation stability. In manufacturing the separator, the method of extruding and molding the unstretched sheet implements a continuous process. That is, the unstretched sheet extruded and molded is put into the annealing process without delay. The extrusion and molding apparatus for the continuous process will be described in detail later.

Next, annealing is performed on the unstretched sheet (S11). The annealing promotes crystallization throughout the sheet, increases crystallite size and removes defects. The annealing is performed at a temperature about 2° C. to 20° C. lower than the melting point of the polymer resin for several seconds to several tens of minutes, for example, 30 seconds to 30 minutes, more preferably about 60 seconds to 5 minutes. For example, an unstretched sheet made of polypropylene is annealed in the range of about 140°C to 170°C. The unstretched sheet subjected to annealing is put into a low-temperature stretching process without delay. The annealing apparatus for the continuous process will be described in detail later.

Subsequently, low-temperature stretching is performed on the unstretched sheet after annealing to form cracks on the surface of the sheet (S12). In the low-temperature stretching process, stretching may be performed in the longitudinal direction using a stretching roll. The temperature of the low-temperature stretching process may be set to a temperature capable of forming cracks in the amorphous region depending on the type of semi-crystalline polymer compound. For example, based on the melting temperature (Tm) of the polymer compound used, it is appropriate between (Tm-150°C) and (Tm-60°C). At a temperature lower than (Tm-150°C), there is a high possibility of breakage during low-temperature stretching, and it is difficult to form uniform cracks. At a temperature higher than (Tm-60 ℃), a phenomenon in which the formed crack is recovered by the thermal motion of the polymer again occurs. In the low-temperature stretching process, the preferred elongation is 10 to 100%. When the elongation is 10% or less, cracks are not sufficiently formed in the amorphous region, and air permeability is lowered after high-temperature elongation. If it is 100% or more, it causes breakage during the low-temperature stretching process, and the production efficiency is lowered.

Thereafter, the first high-temperature stretching (S13) and the second high-temperature stretching (S14) are performed on the stretched film that has been subjected to the low-temperature stretching. The temperature of the high-temperature stretching is appropriately between (Tm-40°C) and (Tm-10°C) based on the melting temperature (Tm). At a temperature below (Tm-40°C), there is a high possibility of breakage in the process of expanding the pores at the crack portion of the low-temperature stretched film. Cracks formed through low-temperature stretching are similar to some defects in the polymer, and fracture occurs around the crack when force is applied in a state where sufficient heat is not applied. At a temperature higher than (Tm-10°C), the pores are closed because the fluidity of the polymer is high.

Although various high-temperature stretching methods are known, it is preferable to perform stretching at 80 to 300% in machine direction stretching. In some cases, transverse stretching may also be performed after longitudinal stretching. However, in the embodiment of the present invention, since the second high-temperature stretching is performed after the first high-temperature stretching, the degree of stretching is adjusted in the first and second high-temperature stretching. For example, in the case of 140% machine direction stretching, if about 70% is stretched in the first high-temperature stretching, 70% is stretched in the second high-stretching. Accordingly, the first high-temperature stretching has the meaning of adjusting the degree of stretching. In this way, when subjected to the secondary high-temperature stretching, the separator according to the embodiment of the present invention is stretched by several times compared to the stretched sheet subjected to annealing. The separator that has undergone high-temperature stretching called primary and secondary high-temperature stretching relieves heat applied to the separator through heat setting and stabilizes the microstructure (S15). After the heat-setting separator is cooled (S16), it is wound by a winding roll (S17).

An embodiment of the present invention suggests a process of manufacturing a separator in the order of annealing, low-temperature stretching, first and second high-temperature stretching, and heat setting as subsequent processes after manufacturing an unstretched sheet. However, this is merely a presentation of one preferred embodiment, and the subsequent process may be variously modified within the scope of the present invention. Accordingly, the process of manufacturing a separator according to an embodiment of the present invention essentially includes an unstretched sheet manufacturing unit, an annealing unit, and an stretching unit.

3 is a view for explaining an extrusion and molding apparatus applied to a manufacturing apparatus according to an embodiment of the present invention. At this time, the dry separation membrane manufacturing apparatus will refer to FIG. 2 .

According to FIG. 3, the extrusion and molding apparatus includes an extruder 10, an extrusion die 11 and a tension control roller 12. At this time, the molten polymer resin is discharged from the extrusion die 11 in the form of a discharge sheet Fo, and although not particularly limited, a single screw or twin screw extruder and a T-shaped or annular die may be used. In the drawing, a T-shaped die is taken as an example. Between the extrusion die 11 and the tension control roller 12, an air knife 20 for spraying gas for cooling the discharge sheet Fo is disposed. The air knife 20 may be disposed on one side or both sides of the discharge sheet Fo. In the drawing, it is exemplified that it is arranged on both sides. In the case of the discharge sheet Fo having a thin thickness, the discharge sheet Fo can be cooled even if the air knife 20 is disposed on one surface. Here, a description will be given focusing on the case of being disposed on both sides.

An air blower 21, an air conditioner 22, and an injection pipe 23 are attached to the air knife 20. The air blower 21 generates a flow of gas supplied to the air knife 20, and the air conditioner 22 controls the flow rate and temperature of the gas supplied to the air knife 20. The gas that has passed through the air conditioner 22 is supplied to the air knife 20 through the injection pipe 23.

The air knife 20 becomes narrower toward the air injection port 20a, thereby increasing the pressure of the injected gas. The air knife 20 cools the discharge sheet Fo discharged from the extrusion die 11 to produce an unstretched sheet Fs containing lamellar crystals. Pores are formed in the lamellar crystal as relatively weak amorphous regions are ruptured in a subsequent stretching process, and the pores are expanded in a high-temperature stretching process to form a separator having a microporous structure. The aspect of the lamellar crystal depends on the cooling rate of the discharge sheet Fo. Specifically, the faster the cooling rate promotes the formation of lamellar crystals, but the excessively rapid cooling rate adversely affects secondary crystallization, which is the lamellar growth step. Accordingly, in order to have a suitable porosity according to the purpose of the separation membrane, the cooling rate is appropriately adjusted using the air knife 20. Typically, the temperature of the gas is preferably 10 to 30 degrees, and if it exceeds 30 degrees, the cooling effect is reduced.

The air knife 20 is preferably disposed on both sides of the discharge sheet Fo in order to prevent vibration of the discharge sheet Fo during the cooling process and to enhance the cooling effect of the discharge sheet Fo. Vibration of the discharge sheet Fo can be eliminated by adjusting the position, angle, air volume and air speed of the air knife 20 . The position of the air injection port 20a has a first distance D1 from the extrusion die 11 and a second distance D2 from the discharge sheet Fo. The first interval D1 is preferably 5 mm to 70 mm. If it is smaller than 5 mm, the sheet Fs is cooled too quickly, so that the unstretched sheet Fs is not properly formed. If it is larger than 70 mm, cooling of the discharge sheet Fo is not performed well, so that the crystallinity of the unstretched sheet Fs is reduced and pores are not easily formed in the subsequent process. The second interval D2 is preferably 10 mm to 50 mm. If it is smaller than 10 mm, vibration of the discharge sheet Fo occurs, and if it is larger than 50 mm, cooling of the discharge sheet Fo is not performed properly.

When the air knives 20 are disposed on both sides, the air jetting ports 20a form first and second jetting angles θ1 and θ2 with respect to the discharge sheet Fo. When the first and second jetting angles θ1 and θ2 are formed, the gas jetted from the air jetting hole 20a is jetted toward the discharge sheet Fo at the first and second jetting angles θ1 and θ2. The first and second spraying angles θ1 and θ2 are preferably 40 degrees to 90 degrees. When the first and second blowing angles θ1 and θ2 are less than 40 degrees, it is difficult to install the air nozzle 20a on the extrusion die 11, and the gas coming out of the air nozzle 20a is discharged from the lower part of the discharge sheet Fo. contact and cooling is not performed properly. If the angle is greater than 90 degrees, the injected gas flows back into the extrusion die 11 to cool the extrusion die 11 . The first and second spray angles θ1 and θ2 may be set differently from each other in consideration of cooling efficiency. In addition, even when the air knife 20 is disposed on one surface, a predetermined spraying angle is formed with respect to the discharge sheet Fo, and the spraying angle is preferably 40 to 90 degrees.

The first and second injection angles θ1 and θ2 allow the gas injected from the air injection hole 20a to flow to the opposite side of the extrusion die 11 . However, some of the injected gas flows in the direction of the extrusion die 11 . In order to prevent cooling of the extrusion die 11 by the gas, a heating unit 30 is installed in the nozzle portion of the extrusion die 11 . If there is no heating unit 30, the nozzle of the extrusion die 11 is cooled by the gas, so that the discharge sheet Fo is not formed well.

The wind speed of the air nozzle 20a is preferably 10 m/s to 100 m/s. 10 m/s is the minimum wind speed for effectively cooling the discharge sheet Fo, and if it exceeds 100 m/s, vibration of the discharge sheet Fo occurs. Meanwhile, the extrusion die 11 and the tension control roller 12 have a third distance D3 of 50 mm to 150 mm. If it is smaller than 50 mm, cooling of the discharge sheet Fo is not performed properly, and if it exceeds 150 mm, wrinkles occur in the discharge sheet Fo. The rotational speed of the tension control roller 12 controls the tension applied to the discharge sheet Fo and the unstretched sheet Fs.

In the process of manufacturing the unstretched sheet (Fs) according to the embodiment of the present invention, the bottleneck is excluded from the molding speed of extrusion and molding. When the bottleneck phenomenon occurs, the unstretched sheet Fs cannot be continuously introduced into the subsequent process. For example, the conventional molding speed is greater than 40 m/m and less than 100 m/m, and the molding speed is a bottleneck in the annealing process. Conventionally, since casting rolls are used, the molding speed is maintained at 40 m/m to 100 m/m in order to smoothly cool the discharge sheet Fo. However, the molding speed causes a bottleneck that cannot be continuously introduced into the annealing process without delay. That is, the bottleneck refers to a state in which the uncontinuous sheet Fs cannot be continuously introduced into the annealing process without delay. In this way, since it is difficult to apply the conventional continuous process, the separator is inevitably manufactured in a discontinuous process.

In order to manufacture a separator in a continuous process, the molding speed of the present invention is preferably 1 m/m to 40 m/m. If the molding speed is less than 1 m/m, the production of the separator is too small. If the molding speed is greater than 40 m/m, the annealing and stretching processes must be relatively long, increasing equipment cost and equipment area. In addition, when the molding speed is high, the air volume of gas for rapid cooling of the discharge sheet Fo is increased. When the air volume increases, vibration of the discharge sheet Fo occurs, making it difficult to manufacture an unstretched sheet Fs having a uniform thickness.

The first to third intervals (D1, D2, D3), the first and second spray angles (θ1, θ2), the wind speed, the gas temperature, and the molding speed according to the embodiment of the present invention are applied for the continuous process. 20) is based on the technical idea of the present invention. Accordingly, the first to third intervals (D1, D2, D3), the first and second spray angles (θ1, θ2), the wind speed, the gas temperature, and the molding speed are repeated experiments without considering the technical idea. It cannot be obtained through This is because the first to third intervals D1, D2, and D3, the first and second spray angles θ1 and θ2, wind speed, gas temperature, and molding speed are not derived in the conventional method using a casting roll. Because.

4 is a view for explaining an annealing unit 40 applied to a manufacturing apparatus according to an embodiment of the present invention. At this time, the dry separation membrane manufacturing apparatus will refer to FIG. 2 .

Referring to FIG. 4 , the annealing unit 40 includes an oven 41, a plurality of transfer rollers 42 and 43, and a tenter clip chain 50. The oven 41 includes devices that apply thermal energy within the oven 41 . The tenter clip chain 50 is bound to the plurality of conveying rollers 42 and 43 and moves according to the rotation of the conveying rollers 42 and 43, and the unstretched sheet Fs is fixed. In the tenter clip chain 50, all known methods can be applied to the binding and rotation of the plurality of conveying rollers 42 and 43 and the method of fixing the unstretched sheet Fs. The annealing unit 40 is formed by combining an oven roll driving method and a tenter clip chain method. Substantially, the annealing speed of the unstretched sheet Fs proceeds at an annealing speed of, for example, 1 m/m to 40 m/m for effective annealing. If the annealing speed differs from the forming speed, a bottleneck phenomenon may occur. To this end, when the separator is manufactured in a batch method, it is preferable to block the bottleneck phenomenon by increasing the length of the annealing process together with controlling the molding speed.

In order to increase the length of the annealing process, the plurality of conveying rollers 42 and 43 include a pair of conveying rollers 42 and 43 in which the unstretched sheet Fs forms a unit length L. There are a plurality of sets of a pair of conveying rollers 42 and 43 constituting a unit length L. In the drawing, five sets are taken as an example. When the number of sets of transfer rollers 42 and 43 increases, the length of the annealing process increases. If the length of the annealing process is increased, it is possible to block the bottleneck caused by the difference between the forming speed of the unstretched sheet Fs and the annealing speed. At this time, each set of conveying rollers (42, 43) is spaced apart by the distance (S). The length of the annealing process is set by adjusting the number of sets of the transfer rollers 42 and 43, the unit length (L), and the spacing (S).

Hereinafter, in order to explain the physical properties of the separation membrane of the present invention in detail, the following experimental examples are presented. However, the present invention is not particularly limited to the following experimental examples. In addition, the physical properties of the separation membrane according to the experimental example show values measured by the following method.

1) Air permeability (seconds)

- Measuring instrument name: Gurley Type Densometer Model G-B2C from Toyoseiki, Japan.

-Measurement method: In accordance with JIS P8117, it was measured at a temperature of 23±2° C. and a humidity of 50±5% RH in seconds/100 ml, which is the time for 100 ml to pass.

2) Penetration strength (gf)

- Measuring instrument name: Penetrate strength meter of Korea BMS Tech Co., Ltd.

- Measurement method: A puncture test was conducted with a 1 mm probe, and the maximum puncture load was used as the puncture strength. Here, the sample was fixed in a metal frame (sample holder) with a hole of Φ 11.3 mm, and measurement was performed.

3) Heat shrinkage rate (%)

- Measuring instrument name: circulation oven

-Measurement method: A square sample with a length of 10 cm was left in an oven at 105 ° C. for 1 hour, and then the shrinkage rate in the longitudinal direction was measured.

4) Porosity (%)

- Name of Measuring Instrument: Precision Scale & Thickness Measuring Instrument

- Measurement method: The volume was obtained from the thickness and area of the separator, the weight was measured, and the calculated value was expressed as vol% by reflecting the specific gravity of polypropylene.

<Experimental example>

28.5 μm, 22.5 μm, 18 μm, and 14 μm of unstretched sheets (Fs) made of a resin mixture of 98 wt% of polypropylene (Homo PP) and 2 wt% of other additives were prepared. Then, each of the unstretched sheets (Fs) was annealed at 160°C for 180 seconds, followed by low-temperature stretching at 45°C for 30 seconds, 1.3 times, and then first high-temperature stretching at 150°C for 2 minutes, 1.6 times. . Subsequently, the second high-temperature stretching was performed at 155° C. for 2 minutes and 2.3 times higher, followed by heat setting at 160° C. for 1 minute. The physical properties of the heat-set membrane were measured. At this time, the preparation of the unstretched sheet, annealing, low-temperature stretching, first and second high-temperature stretching, heat setting, and winding are all performed continuously without delay. The thickness of the prepared separator was 26 μm, 20.1 μm, 16.1 μm, and 12.2 μm, respectively.

Table 1 shows the physical properties of the separation membrane according to the experimental examples of the present invention. 5 to 8 are photographs magnified by 20,000 times the separation membrane of the experimental example, respectively.

Unstretched sheet thickness (㎛) 28.5 22.5 18 14 Separator thickness (㎛) 26 20.1 16.1 12.2 Air permeability (seconds) 280 234 195 160 Passage strength (gf) 320 300 220 193 105℃ MD heat shrinkage (%) 2.5 2.5 2.5 2.5 Porosity (%) 40 40 40 40

According to Table 1, even if the thickness (μm) of the unstretched sheet was decreased, both the heat shrinkage (%) and the porosity were the same. If the thermal contraction rate (%) and the porosity (%) are the same, it means that the continuous process of the present invention is properly performed regardless of the thickness (μm). Thermal shrinkage (%) and porosity (%) vary depending on annealing and stretching conditions. The heat shrinkage rate (%) of 2.5% and porosity (%) of 40% presented in Table 1 were obtained according to the experimental examples of the present invention.

The air permeability (sec) and penetration strength (gf) differ in physical properties depending on the thickness. Specifically, in the dry separation membrane, the thinner the thickness, the lower the air permeability (%) and the lower the penetration strength (gf). Typically, the air permeability (seconds) of the separator is preferably around 200 seconds, and the penetration strength (gf) is preferably 200 gf or more. Accordingly, when the thickness (μm) of the unstretched sheet is 28.5 μm, 22.5 μm, and 18 μm, the air permeability (sec) is 280, 234, and 195, and the puncture strength (gf) is 320, 300, and 220, It can be sufficiently applied as a separator. However, when the thickness (μm) of the unstretched sheet is 14 μm, air permeability (seconds) and puncture strength (gf) are insufficient. However, even if the air permeability (sec) and penetration strength (gf) are insufficient, it can be applied to the separator through surface modification or coating.

In the above, the present invention has been described in detail with preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. possible.

10; extruder 11; extrusion die
12; Tension control roller 20; air knife
21; air blower 22; air conditioner
23; injection tube 30; heating part
40; annealing unit 41; Oven
42, 43; Transfer roller 50; tenterclip chain

Claims (13)

An unstretched sheet manufacturing unit, an annealing unit into which the unstretched sheet is continuously input without delay, and a stretching unit into which the annealed unstretched sheet is continuously input without delay,
The unstretched sheet production unit,
an extrusion die for discharging the molten polymer resin to a discharge sheet;
a tension control roller arranged spaced apart from the extrusion die by a third distance (D3); and
An air knife disposed between the extrusion die and the tension control roller and converting the discharge sheet into the unstretched sheet by cooling the discharge sheet using an air nozzle for injecting a cooling gas into the discharge sheet,
The tension control roller controls the tension applied to the discharge sheet and the unstretched sheet,
The air injection hole forms a first distance D1 from the extrusion die and a second distance D2 from the discharge sheet, the first distance D1 is 5 mm to 70 mm, and the second distance D2 is 10 mm to 50 mm, the third interval (D3) is 50 mm to 150 mm,
A dry separation membrane manufacturing apparatus using a continuous process, characterized in that a heating unit is installed in the nozzle of the extrusion die to prevent cooling of the extrusion die by a part of the cooling gas injected through the air injection hole. delete The apparatus of claim 1, wherein the air knife has a narrower width toward the air nozzle. delete The apparatus of claim 1, wherein the wind speed of the cooling gas sprayed from the air nozzle is 10 m/s to 100 m/s. The apparatus of claim 1, wherein the air knife is disposed on one side or both sides of the discharge sheet. The method of claim 6, when the air knife is disposed on both sides, the air injection hole forms first and second injection angles (θ1, θ2) with respect to the discharge sheet, and the first and second injection angles ( θ1, θ2) is a dry separation membrane manufacturing apparatus using a continuous process, characterized in that 40 to 90 degrees. [8] The apparatus of claim 7, wherein the first and second spraying angles (θ1, θ2) are different from each other. delete [Claim 2] The dry type separator manufacturing apparatus using a continuous process according to claim 1, characterized in that the molding speed of the unstretched sheet is 1 m/m to 40 m/m. The method of claim 1, wherein the annealing unit includes an oven supplying thermal energy, a plurality of conveying rollers, and tenter clip chains, the tenter clip chains being bound to the plurality of conveying rollers and moving according to the rotation of the conveying rollers, and A dry separation membrane manufacturing apparatus using a continuous process, characterized in that the new sheet is fixed. [Claim 12] The apparatus of claim 11, wherein the plurality of conveying rollers includes a plurality of conveying roller sets of a pair forming a unit length of the unstretched sheet. [Claim 13] The apparatus of claim 12, wherein the process length of the annealing unit is determined according to the number of sets, the unit length, and the distance between the sets.

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