Manufacturing method and manufacturing device for microporous polyolefin resin sheet

Abstract

To provide a manufacturing method of a microporous polyolefin resin sheet capable of stably manufacturing a sheet and a manufacturing apparatus thereof.SOLUTION: A manufacturing method of a sheet discharges a sheet material 3 prepared by mixing a polyolefin resin and a dilution material to a cast apparatus 2 from a discharge port 5 of a nozzle 1, covers a vacuum space between the sheet material and the cast apparatus with a vacuum chamber 4 assembled on an upstream side in a sheet transportation direction than the discharge port, brings the sheet material into tight bond with the cast apparatus while sucking air in the vacuum chamber, and cools and solidifies the sheet material while being transported by using the cast apparatus, wherein sucking the air in the vacuum chamber is performed from an opening 8 of the vacuum chamber formed outside in a sheet width direction of both edges of the sheet material, when the shortest distance from the discharge port to an outer peripheral surface of the cast apparatus is H, and, when an area opened at a downstream portion in a sheet transportation direction than the sheet material is S1 when observing the opening from the outside in the sheet width direction, 0<S1 / H2≤0.33 is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for producing a microporous polyolefin resin sheet. [Background technology]

[0002] First, a general method for producing a microporous polyolefin resin sheet will be described with reference to Fig. 7. Fig. 7 is a schematic diagram of a general apparatus for producing a microporous polyolefin resin sheet. As shown in Fig. 7, a sheet material 3, which is a mixture of a polyolefin resin and a diluent, is discharged from a discharge port 5 of a die 1 toward a casting device 2, a reduced pressure space 9 between the sheet material 3 and the casting device 2 is covered with a reduced pressure chamber 4 provided upstream of the discharge port 5 in the sheet conveying direction, air is sucked from the reduced pressure chamber 4 through openings 8 of the reduced pressure chamber 4 formed outside both ends of the sheet material 3 in the sheet width direction to bring the sheet material 3 into close contact with the casting device 2, and the sheet material 3 is cooled and solidified while being conveyed by the casting device 2 in a sheet manufacturing method.

[0003] Incidentally, as a technology that at first glance appears similar to a preferred embodiment of the present invention, there is a resin sheet manufacturing apparatus disclosed in Patent Document 1. Patent Document 1 discloses a resin sheet manufacturing apparatus that is provided with a straightening plate near the end of the sheet material in order to suppress thickness unevenness caused by membrane vibration of the sheet material. Please refer to FIG. 8. FIG. 8 is an arrow view observed from above in the height direction of the resin sheet manufacturing apparatus of Patent Document 1. As shown in FIG. 8, the straightening effect of the straightening plate 6 suppresses the formation of vortexes at the end of the sheet material 3, suppressing membrane vibration of the sheet material and reducing thickness unevenness of the resin sheet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-180847 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a strong demand for thinner resin sheets as products in which resin sheets are used become smaller and lighter. However, when the resin sheet is made thinner, the position at which the sheet discharged from the nozzle lands on the casting device is likely to change when the pressure inside the decompression chamber changes due to external factors such as pulsation of the blower air volume or temperature changes between day and night. If the sheet position changes, the sheet material comes into contact with the side walls of the decompression chamber, causing the sheet to break.

[0006] However, the above-mentioned Patent Document 1 does not disclose seat tearing caused by changes in seat position or a method for preventing this.

[0007] Therefore, the present invention provides a method and apparatus for producing a microporous polyolefin resin sheet that can stably produce a sheet by suppressing changes in sheet position due to pressure fluctuations in a decompression chamber. [Means for solving the problem]

[0008] The method for producing a microporous polyolefin resin sheet of the present invention, which solves the above problems, comprises discharging a sheet material, which is a mixture of a polyolefin resin and a diluent, from an outlet of a die toward a casting device, covering a reduced pressure space between the sheet material and the casting device with a reduced pressure chamber provided upstream of the outlet in the sheet transport direction, sucking air from within the reduced pressure chamber to bring the sheet material into close contact with the casting device, and cooling and solidifying the sheet material while transporting it with the casting device, The air in the decompression chamber is sucked through an opening of the decompression chamber formed on the outer side of both ends of the sheet material in the sheet width direction, The shortest distance from the discharge port to the outer peripheral surface of the casting device is H, and the area of ​​the opening at the downstream side of the sheet conveying direction from the sheet material when observing the opening from the outside in the sheet width direction is S1. <S1 / H 2 ≦0.33.

[0009] In the method for producing a microporous polyolefin resin sheet of the present invention, when the cross-sectional area of ​​the decompression space of the decompression chamber observed from the outer side in the sheet width direction is M1, M1 / H 2 It is preferable that the ratio is ≦2.0.

[0010] In the method for producing a microporous polyolefin resin sheet of the present invention, it is preferable that the decompression chamber includes a shielding plate that partially covers the opening, and S1 is adjusted by changing the area that the shielding plate covers the opening.

[0011] In the method for producing a microporous polyolefin resin sheet of the present invention, it is preferable to control the area of ​​the opening covered by the shielding plate based on the position of the sheet material.

[0012] The present invention provides a microporous polyolefin resin sheet manufacturing apparatus that solves the above problems, the apparatus comprising: a die for discharging a sheet material, which is a mixture of a polyolefin resin and a diluent, from an outlet; a casting device for cooling and solidifying the sheet material discharged from the outlet while conveying the sheet material; and a decompression chamber that is provided upstream of the outlet in the sheet conveying direction and covers a decompressed space between the sheet material and the casting device, A hypothetical sheet material flow from the discharge port to the casting device during sheet production is defined as a virtual sheet material. The decompression chamber is An opening for sucking air from within the decompression chamber is formed at a position on the outer side of both ends of the virtual sheet material in the sheet width direction, The shortest distance from the discharge port to the outer peripheral surface of the casting device is H, and the area of ​​the opening in the downstream portion of the sheet conveying direction from the virtual sheet material when observing the opening from the outside in the sheet width direction is S1. <S1 / H 2 ≦0.33.

[0013] In the manufacturing apparatus for a microporous polyolefin resin sheet of the present invention, when the cross-sectional area of ​​the decompression space observed from the outer side in the sheet width direction is M1, the cross-sectional area of ​​the decompression chamber is M1 / H 2 It is preferable that they are arranged so that the ratio is ≦2.0.

[0014] In the microporous polyolefin resin sheet manufacturing apparatus of the present invention, it is preferable that the decompression chamber is provided with a shielding plate that partially covers the opening, and S1 can be adjusted by changing the area that the shielding plate covers the opening.

[0015] The apparatus for producing a microporous polyolefin resin sheet of the present invention preferably includes a displacement meter for measuring the position of the sheet material.

[0016] [Terminology] Next, the meaning of each term in the present invention will be explained. The term "sheet material" refers to a material that constitutes a sheet. As the sheet material, for example, a polyolefin solution resin prepared by mixing a polyolefin resin such as polyethylene, polypropylene, polystyrene, or polymethylpentene with a diluent and heating and melting it can be used. The diluent is not particularly limited as long as it can be mixed or dissolved in the polyolefin resin. A solvent that is miscible with the polyolefin in the melt-kneaded state but is solid at room temperature may be mixed with the diluent. Examples of such solid diluents include stearyl alcohol, ceryl alcohol, and paraffin wax. In order to prevent spots during stretching, and in consideration of subsequent application, it is preferable that the diluent is liquid at room temperature. Examples of liquid diluents include aliphatic, cycloaliphatic, or aromatic hydrocarbons such as nonane, decane, decalin, paraxylene, undecane, dodecane, and liquid paraffin, and mineral oil fractions whose boiling points correspond to these, as well as phthalic acid esters that are liquid at room temperature, such as dibutyl phthalate and dioctyl phthalate. In order to obtain a gel-like sheet with a stable content of the liquid diluent, it is more preferable to use liquid paraffin. For example, the viscosity of the liquid diluent is preferably 20 to 200 cSt at 40° C. The blending ratio of the polyolefin resin and the diluent is preferably 10 to 50 mass% of the polyolefin resin, with the total of the polyolefin resin and the diluent being 100 mass%, from the viewpoint of improving the moldability of the extrudate. The homogeneous melt-kneading process of the polyolefin solution is not particularly limited, but examples thereof include a calendar, various mixers, and an extruder equipped with a screw.

[0017] The term "casting device" refers to a device that conveys a sheet material discharged from a nozzle of a die downstream while cooling and solidifying it by bringing the sheet material into close contact with the material. The form of the casting device is not particularly limited, but examples thereof include rolls and belts. The term "width direction" refers to the direction that coincides with the width direction of the sheet material when it is formed into a sheet by a die. The term "sheet conveying direction" refers to the direction in which the casting device conveys the sheet. The conveying destination is the downstream side, and the opposite side is the upstream side. "Reduced pressure space" refers to a space formed between the sheet material and the casting device, which is covered with a reduced pressure chamber and is under negative pressure. The term "vacuum chamber" refers to a device that covers a vacuum space and reduces the pressure to bring the sheet material into close contact with the casting device. In general, the pressure in the vacuum chamber is between -1500 Pa and -50 Pa relative to atmospheric pressure. The pressure in the vacuum chamber may be controlled according to the film-forming conditions.

[0018] The "opening" refers to a part of the vacuum chamber that is connected to a suction device and sucks air from inside the vacuum chamber. The shape of the opening is not particularly limited, but examples thereof include a square, a rectangle, a trapezoid, a circle, and an ellipse. The opening may be subjected to a surface treatment such as nickel plating, chrome plating, or zinc plating. The suction device is not particularly limited, but examples thereof include a blower and a vacuum pump. The term "shielding plate" refers to a member that partially covers an opening. The shape of the shielding plate is not particularly limited, but examples include a plate material and a punched material with holes. The "virtual sheet material" is a projection of the flow of sheet material from the discharge outlet to the casting device during sheet production, and the sheet width of the virtual sheet material, the position where it lands on the casting device, and the trajectory from the discharge outlet to the casting device change depending on the production conditions. The "side wall" refers to a portion of the decompression chamber that covers the surface of the decompression space perpendicular to the sheet width direction. Effect of the Invention

[0019] By using the polyolefin resin sheet manufacturing method and manufacturing apparatus of the present invention, it is possible to suppress changes in the sheet position due to pressure fluctuations in the decompression chamber, thereby suppressing sheet rupture, and to stably manufacture the sheet. [Brief description of the drawings]

[0020] [Figure 1] 1 is a view of the apparatus for producing a microporous polyolefin resin sheet of the present invention, as viewed from the sheet width direction. FIG. [Diagram 2] 2 is a cross-sectional view perpendicular to the height direction along the line XX in FIG. 1. [Diagram 3] FIG. 1 is a view of a typical apparatus for producing a microporous polyolefin resin sheet, as viewed from the sheet width direction. [Figure 4] 4 is a cross-sectional view perpendicular to the height direction along the line ZZ in FIG. 3. [Diagram 5] FIG. 2 is an arrow view of the production apparatus for a microporous polyolefin resin sheet of the present invention, observed from the sheet width direction, showing a reduced pressure space. [Figure 6] 1 is a view of a polyolefin resin sheet production apparatus of the present invention equipped with a shielding plate, as viewed from the sheet width direction. [Figure 7] FIG. 1 is a schematic diagram of a typical production apparatus for a microporous polyolefin resin sheet. [Figure 8] 1 is a view seen from above in the height direction of the resin sheet manufacturing apparatus of Patent Document 1. FIG. [Figure 9] 11 is a graph showing S1 / H2 and seat position change in each example and comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the manufacturing method and production method of the polyolefin resin sheet of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments described here. Note that the same reference numerals may be used for members having the same uses and functions as those in the prior art. Each dimension will be described with reference to Figs. 1 and 2. Fig. 1 is an arrow view of the manufacturing apparatus of the polyolefin resin sheet of the present invention observed from the sheet width direction, and Fig. 2 is a cross-sectional view perpendicular to the height direction along the line XX in Fig. 1. When the opening 8 is observed from the outside in the sheet width direction, the area of ​​the part that is open downstream of the sheet material 3 in the sheet conveying direction is designated by symbol S1, and the shortest distance from the discharge port of the die 1 to the outer circumferential surface of the casting device 2 is designated by symbol H.

[0022] First, referring to Figures 3 and 4, the change in sheet position due to pressure fluctuations in the decompression chamber 4 will be described. Figure 3 is an arrow view of a typical polyolefin resin sheet manufacturing device observed from the sheet width direction, and Figure 4 is a cross-sectional view perpendicular to the height direction along line ZZ in Figure 3. When the negative pressure in the decompression chamber 4 becomes stronger due to an external factor, the sheet material 3 is drawn upstream in the sheet conveying direction and moves from position A to position B. Then, the edge of the sheet material 3 comes into contact with the upstream edge 8a of the opening 8 in the sheet conveying direction or the side wall 4a of the decompression chamber 4, causing the sheet to tear.

[0023] As a result of repeated experiments and theoretical calculations, the inventors of the present invention found that the sheet position change due to the pressure fluctuation in the decompression chamber 4 can be suppressed by reducing S1. With reference to FIG. 2, the sheet position change due to the pressure fluctuation in the decompression chamber 4 in the polyolefin resin sheet manufacturing apparatus of the present invention in which S1 is small will be described. S1 increases when the sheet material 3 moves upstream in the sheet conveying direction. Then, the flow resistance of the opening 8 decreases according to the increase rate of S1, and the suction pressure of the suction device (not shown) that sucks air also becomes weaker. As a result, the negative pressure in the decompression chamber 4 also becomes weaker. When S1 is large as in a general polyolefin resin sheet manufacturing apparatus, the increase rate of S1 due to the movement of the sheet material 3 is small, and the effect on the negative pressure in the decompression chamber 4 is also small. On the other hand, when S1 is small as in the polyolefin resin sheet manufacturing apparatus of the present invention, the increase rate of S1 is large, and the negative pressure in the decompression chamber 4 is also significantly weakened. As a result, the sheet material 3 tries to return to position A before moving to position B, so that the sheet position change due to the pressure fluctuation in the decompression chamber 4 can be suppressed.

[0024] Here, the inventors further conducted experiments and theoretical calculations, and found that 0 <S1 / H 2It was found that by making S1 ≦0.33, it is possible to suppress the change in sheet position due to pressure fluctuations within the decompression chamber 4 and prevent sheet tearing. When S1=0, in other words when there is no opening in the opening 8 downstream of the sheet material in the sheet conveying direction, the flow resistance of the opening 8 does not change significantly even when the sheet material 3 moves, so the effect on the suction pressure of the suction device and the negative pressure within the decompression chamber 4 is also small. In addition, since the amount of change in position of the sheet material 3 due to the negative pressure within the decompression chamber 4 depends on H, the range in which the effects of the present invention can be obtained is defined by S1 normalized by H. More preferably, 0 <S1 / H 2 ≦0.20. There are no particular limitations on the range of H, but if the opening 8 is too small, it becomes prone to clogging with foreign matter, and therefore, in reality, H is preferably 10 mm or more.

[0025] 5 is an arrow view of the polyolefin resin sheet manufacturing apparatus of the present invention, observed from the sheet width direction, showing the reduced pressure space. In reality, the reduced pressure space is obscured by the side wall of the reduced pressure chamber 4, but the figure is taken as if there were no side wall. As shown in FIG. 5, when the cross-sectional area of ​​the reduced pressure space observed from the outside in the sheet width direction is designated as M1, in the polyolefin resin sheet manufacturing method of the present invention, M1 / H 2 It is preferable to set M1 / H to ≦2.0. 2 The effect of the present invention can be obtained even if M1 / H is larger than 2.0. 2 By making M1 / H equal to or less than 2.0, the effect of the reduction in the suction pressure of the suction device is transmitted to the entire inside of the decompression chamber 4 in a short time, and the change in the seat position can be further suppressed. 2 ≦1.7. M1 / H 2 There is no particular lower limit to M1 / H. However, if M1 is too small, the negative pressure in the decompression chamber 4 becomes non-uniform in the width direction. 2 is preferably 1.3 or more.

[0026] In the polyolefin resin sheet manufacturing method of the present invention, it is preferable to adjust S1 by changing the area that the shielding plate covers the opening. Please refer to Fig. 6. Fig. 6 is an arrow view of a polyolefin resin sheet manufacturing apparatus of the present invention equipped with a shielding plate 7, observed from the sheet width direction. S1 can be adjusted by moving the shielding plate 7 in the sheet conveying direction to change the area that covers the opening 8. Even if the position of the sheet material 3 changes due to a change in conditions, etc., S1 can be adjusted to an appropriate range without modifying the apparatus.

[0027] In the method for producing a polyolefin resin sheet of the present invention, it is preferable to control the area that the shielding plate 7 covers over the opening, based on the position of the sheet material 3. Even if the position of the sheet material 3 changes during film formation due to the environmental temperature, resin state, etc., by controlling the area that the shielding plate 7 covers over the opening 8, based on the position of the sheet material 3, S1 can be maintained within an appropriate range.

[0028] The polyolefin resin sheet manufacturing apparatus of the present invention is preferably equipped with a displacement meter (not shown) for measuring the position of the sheet material. The displacement meter and the shielding plate 7 may be connected to a control device (not shown), and the position of the shielding plate 7 may be automatically controlled from the control device in response to a signal indicating the position of the sheet material from the displacement meter. EXAMPLES

[0029] Hereinafter, an example of polyolefin resin sheet production using the polyolefin resin sheet production method of the present invention will be described. Here, the area of ​​the opening portion that is open downstream of the sheet material in the sheet conveying direction when observed from the outside in the sheet width direction is defined as S1 [mm 2 ], the shortest distance from the nozzle of the die to the outer periphery of the casting device is H [mm], and the cross-sectional area of ​​the reduced pressure space observed from the outside in the sheet width direction is M1 [mm 2 ].

[0030] [Example 1] A polyolefin resin sheet was actually produced using the polyolefin resin sheet production method of the present invention shown in Fig. 1, and the results of evaluating the amount of sheet position change due to pressure fluctuation will be described. The specific sheet production conditions in this embodiment are as follows.

[0031] (1) Sheet material: High density polyethylene (HDPE): Viscosity 1000 Pa·s. Here, the viscosity was measured at a shear rate of 100 / s and a temperature of 200°C according to the method of JIS K7117-2. Liquid paraffin (LP): Dynamic viscosity 50 cSt (40 °C mm 2 / s). The blend ratio of HDPE and LP is HDPE:LP=30:70 by mass.

[0032] (2) Extrusion: The sheet material was extruded at a flow rate of 250 kg / hr using an extruder, and fed to a die via a gear pump and a filter. The temperature of the device up to the die was 220°C.

[0033] (3) Base: The sheet material was discharged from a discharge port having a width of 500 mm and a gap of 2 mm, and formed into a sheet.

[0034] (4) Casting equipment: The sheet was brought into close contact with a sheet forming roll rotating at a temperature of 35°C and a speed of 10 m / min, and then cooled and solidified. The discharge port of the die was set directly above the center of the sheet forming roll, at a position with a height of 40 mm.

[0035] (5) Decompression chamber: The decompression chamber is installed upstream of the nozzle in the conveying direction and covers the space between the sheet material discharged from the nozzle and the casting device. M1 is 3400 mm. 2 and M1 / H 2= 2.1. The opening was a rectangle with the long side in the horizontal direction, with the long side being 70 mm and the short side being 32 mm. The distance from the nozzle outlet to the upper end of the opening was 3 mm, and the distance from the lower end of the opening to the sheet forming roll was 5 mm. The inside of the decompression chamber was sucked to -400 Pa by a blower connected to the opening, and S1 was 320 mm. 2 , S1 / H 2 =0.20.

[0036] (6) Seat position change amount The pressure in the decompression chamber was forcibly changed to -600 Pa, and the distance by which the position where the sheet material landed on the casting device moved upstream in the sheet conveying direction (hereinafter referred to as the sheet position change) was measured, and it was found to be 7.5 mm.

[0037] [Examples 2 to 5, Comparative Examples 1 to 4] A sheet was produced by the same polyolefin resin sheet production method as in Example 1, except that the dimensions of the decompression chamber were changed as shown in Tables 1 and 2. Tables 1 and 2 show the dimensions of the decompression chamber and the amount of change in seat position in each of the examples and comparative examples.

[0038] [Table 1]

[0039] [Table 2]

[0040] [Evaluation Results] Referring to FIG. 9, S1 / H 2 The relationship between the seat position change amount and the seat position change amount will be described. FIG. 9 is a graph showing the seat position change amount in each example and comparative example. The horizontal axis is S1 / H 2 The vertical axis represents the amount of change in seat position, ◯ represents Examples 1 to 5, × represents Comparative Examples 1 to 4, and the dotted line represents 0. <S1 / H 2 The range is ≦0.33.

[0041] In the methods for producing polyolefin resin sheets in Examples 1 to 4, 0 <S1 / H 2 ≦0.33, the negative pressure in the decompression chamber was significantly weakened by the movement of the sheet material, and the amount of sheet position change was suppressed to 3.3 to 9.2 mm.

[0042] In the method for producing a polyolefin resin sheet of Example 5, S1 / H 2 was the same as in Example 1, but M1 / H 2 Since the difference was ≦2.0, the effect of the decrease in suction pressure of the suction device was transmitted to the entire inside of the decompression chamber 4 in a short time, and the amount of change in the seat position was suppressed to 5.1 mm, which was lower than 7.5 mm in the first embodiment.

[0043] In the method for producing a polyolefin resin sheet of Comparative Example 1, S1 / H 2 = 0, the sheet position change was large at 38.6 mm. Note that no sheet material was observed from the opening until the sheet position moved 38.6 mm, and S1 / H 2 =0.

[0044] In the methods for producing polyolefin resin sheets of Comparative Examples 2 to 4, S1 / H 2 >0.33, the seat position change was large, ranging from 33.3 to 38.2 mm. [Industrial Applicability]

[0045] The present invention is not limited to a polyolefin resin sheet manufacturing apparatus and manufacturing method, but can also be applied to a solution resin sheet manufacturing apparatus and manufacturing method, die coating, etc., but the scope of application is not limited to these. [Explanation of symbols]

[0046] 1 Base 2 Casting equipment 3 Sheet material 4. Decompression Chamber 4a side wall 5 Outlet 6 Rectifier plate 7 Shielding plate 8 Openings 8a: upstream end of the opening in the sheet conveying direction 9. Reduced Pressure Space

Claims

1. A sheet material containing a mixture of polyolefin resin and a diluent is discharged from a discharge port of a die toward a casting device, a decompression chamber provided upstream of the discharge port in a sheet conveying direction covers a decompression space between the sheet material and the casting device; A method for manufacturing a sheet, comprising the steps of: sucking air from within the decompression chamber to bring the sheet material into close contact with the casting device; and cooling and solidifying the sheet material while transporting it with the casting device, The air in the decompression chamber is sucked through an opening of the decompression chamber formed on the outer side of both ends of the sheet material in the sheet width direction, When the shortest distance from the discharge port to the outer peripheral surface of the casting device is H, and the area of ​​the opening at the downstream side of the sheet conveying direction from the sheet material when observing the opening from the outside in the sheet width direction is S1, 0<S1 / H ２ ≦0.33, A method for producing a microporous polyolefin resin sheet.

2. When the cross-sectional area of ​​the decompression space when the decompression chamber is observed from the outside in the sheet width direction is M1, M1 / H ２ The method for producing a microporous polyolefin resin sheet according to claim 1, wherein the microporous polyolefin resin sheet has a thickness of ≦2.

0.

3. the decompression chamber includes a shielding plate that partially covers the opening; The method for producing a microporous polyolefin resin sheet according to claim 1 or 2, wherein the S1 is adjusted by changing an area of ​​the shielding plate covering the opening.

4. The method for producing a microporous polyolefin resin sheet according to claim 3 , wherein the area of ​​the shielding plate covering the opening is controlled based on the position of the sheet material.

5. a die for discharging the sheet material, in which the polyolefin resin and the diluent are mixed, from a discharge port; a casting device for cooling and solidifying the sheet material discharged from the discharge port while conveying the sheet material; a decompression chamber provided upstream of the discharge port in a sheet conveying direction and covering a decompression space between the sheet material and the casting device, A virtual sheet material is defined as an expected flow of the sheet material from the discharge outlet to the casting device during the production of the sheet. The decompression chamber comprises: An opening for sucking air from within the decompression chamber is formed at a position on the outer side of both ends of the virtual sheet material in the sheet width direction, When the shortest distance from the discharge port to the outer peripheral surface of the casting device is H, and the opening is observed from the outside in the sheet width direction, the area of ​​the opening downstream of the virtual sheet material in the sheet conveying direction is S1, 0<S1 / H ２ ≦0.33, Manufacturing equipment for microporous polyolefin resin sheets.

6. When the cross-sectional area of ​​the decompression space of the decompression chamber observed from the outside in the sheet width direction is M1, the virtual sheet material is used as a reference and the cross-sectional area is M1 / H ２ The apparatus for producing a microporous polyolefin resin sheet according to claim 5 , wherein the apparatus is arranged so that the ratio of the microporous polyolefin resin sheet thickness to the total microporous polyolefin resin sheet thickness is ≦2.

0.

7. the decompression chamber includes a shielding plate that partially covers the opening; The apparatus for producing a microporous polyolefin resin sheet according to claim 5 or 6, wherein the S1 can be adjusted by changing the area of ​​the shielding plate covering the opening.

8. The apparatus for producing a microporous polyolefin resin sheet according to any one of claims 5 to 7, further comprising a displacement meter for measuring the position of the sheet material.

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