JP2021084051A - Magnetic foreign matter removal method, and magnetic foreign matter removal device and method for producing microporous membrane using the same - Google Patents

Abstract

To provide magnetic foreign matter removal method and device which remove 100% of a magnetic foreign matter in powder with inexpensive constitution, and a method for producing a microporous membrane produced using the magnetic foreign matter removal device.SOLUTION: The magnetic foreign matter removal method brings a sample into contact with a magnet plate by repeated relative movement to the magnet plate in a closed space where the magnet is provided inside a housing, and can remove a magnetic foreign matter in a sample with high efficiency.SELECTED DRAWING: Figure 1(a)

Description

The present invention relates to a technique for removing magnetic foreign substances from a viscous liquid such as a powder or a plasticizer of a thermoplastic resin or a thermocurable resin, an aqueous solution of an acid / alkali, or an organic solvent, and a magnetic foreign matter removing device. A method and device for attracting magnetic foreign matter to a magnet plate by bringing a sample into contact with it. The present invention relates to a method for producing a microporous film produced from a resin powder or liquid that has passed through such a magnetic foreign matter removing device.

The resin powder is processed into various molded bodies by injection mold molding, blow molding, extrusion-cast molding, and the like. These molded products are used in a wide range of applications such as medical treatment, food, and industry, and it is not preferable for hygiene to contain magnetic foreign substances in medical and food applications. Further, in the electric / electronic field for industrial use, magnetic foreign matter contained in a film molded body formed by extrusion-cast molding causes product defects, and particularly in the battery field, for example, lithium ion secondary battery, nickel-. Magnetic foreign matter in the polyolefin microporous film used in hydrogen batteries, nickel-cadmium batteries and polymer batteries may cause short circuits between the electrodes.

In addition, the microporous polyolefin membrane used in the battery is coated with a slurry containing a filler for higher functionality. Similar to the polyolefin microporous membrane, if the slurry also contains magnetic foreign matter, it may cause a short circuit between the electrodes. Similarly, if the electrolytic solution contains magnetic foreign matter, it may cause a short circuit.

Therefore, various techniques for removing magnetic foreign substances in powder by using a magnet bar made of a magnet have been conventionally considered. For example, in Patent Document 1, it is possible to remove magnetic foreign matter by installing a magnet inside the rotary valve, but since it contacts the magnet only while the rotary valve rotates 180 °, it has the ability to remove magnetic foreign matter. There is a risk that it will be insufficient.

In Patent Document 2, a magnet is installed inside the rotating drum and a feeder is placed above the magnet to enable removal of magnetic foreign matter. However, depending on the size of the magnetic foreign matter, centrifugal force may cause magnetic foreign matter to be contained in the sample. There is a risk of contamination. In the case of slurry, it is difficult to control because of its liquid nature, and this method is not suitable.

Japanese Unexamined Patent Publication No. 2002-52348 Japanese Unexamined Patent Publication No. 2009-2008048

Generally, a magnetic foreign matter removing device enhances the magnetic foreign matter removing ability by stacking a large number of magnet units provided with several or more magnet bars in the sample dropping direction or the traveling direction. However, since the magnet bar provided in the magnet unit has a clearance, it is difficult to achieve a contact probability of 100% with the magnet bar. Since it is viscous in the viscous liquid, it is difficult to attract magnetic foreign matter to the magnet bar. In addition, stacking a large number of magnet units to achieve this not only increases the cost, but also complicates the maintenance and management cleaning work.

The present invention has been made in view of the problems of the prior art as described above, and has an inexpensive structure, a magnetic foreign matter removing method capable of efficiently removing magnetic foreign matter from a sample, and a magnetic foreign matter removing method. The purpose is to provide the device.

(Magnetic foreign matter removal method)
In order to achieve the above object, the present invention
This is a magnetic foreign matter removing method capable of removing magnetic foreign matter in a sample with high efficiency by bringing a sample into contact with a magnet plate by repeatedly moving the sample in a closed space provided with a magnet inside the housing.

(Magnetic foreign matter remover)
The removal device is, for example,
The sample in the housing can be agitated by a rotary blade, and is composed of a magnetic foreign matter removing device including a magnet plate in which a part or all of the side surface of the housing is made of a permanent magnet.

By repeatedly contacting the magnet plate with the sample in the housing by stirring by the rotary blade, 100% contact of the sample with the magnet plate is achieved, and 100% of the magnetic foreign matter is removed. The magnet plate is configured as a lid for putting a sample in the housing.

The concentration of magnetic foreign matter in the sample is confirmed in advance by visual inspection or inspection by equipment, and 100% of the magnetic foreign matter is removed by changing the number of rotations of the stirring blade according to the concentration of magnetic foreign matter in the sample. The rotation speed of the rotor is not limited, but the rotation speed is such that the sample does not generate heat due to shear heat generation.

It is composed of a magnetic foreign matter removing device provided with a mechanism for applying vibration to the housing, capable of stirring the sample by vibration, and a magnet plate having a part or all of the side surface of the housing made of a permanent magnet.

When the sample in the housing repeatedly contacts the magnet plate by vibration, 100% contact of the sample with the magnet plate is achieved, and 100% of magnetic foreign matter is removed. The magnet plate is configured as a lid for putting a sample in the housing.

The concentration of magnetic foreign matter in the sample is confirmed in advance by visual inspection or inspection by an instrument, and 100% of the magnetic foreign matter is removed by changing the vibration time of the housing according to the concentration of the magnetic foreign matter in the sample.
The frequency of vibration is not particularly limited, but is a frequency at which the sample does not generate heat due to vibration.

A magnetic foreign matter remover equipped with an air supply mechanism and an exhaust mechanism that put compressed air into the housing, a sample can be agitated by air circulation, and a magnet plate with a part or all of the side surface of the housing made of permanent magnets. It is composed. By repeatedly contacting the magnet plate with the sample in the housing by the convection of air, it is achieved that the sample comes into contact with the magnet plate 100%, and 100% of the magnetic foreign matter is removed. The magnet plate is configured as a lid for putting a sample in the housing.

The concentration of magnetic foreign matter in the sample is confirmed in advance by visual inspection or inspection by an instrument, and 100% of the magnetic foreign matter is removed by changing the convection time of the sample according to the concentration of the magnetic foreign matter in the sample. The pressure of the compressed air used is not particularly limited.

A housing made of polygonal columns or cylinders, which can be rotated around the center of the housing as a rotation axis, and is composed of a magnetic foreign matter removing device provided with a magnet plate in which part or all of the side surfaces of the housing are made of permanent magnets. .. By repeatedly contacting the magnet plate with the sample in the housing by rotation, it is achieved that the sample comes into contact with the magnet plate 100%, and 100% of the magnetic foreign matter is removed. The magnet plate is configured as a lid for putting a sample in the housing.

The concentration of magnetic foreign matter in the sample is confirmed in advance by visual inspection or inspection by an instrument, and 100% of the magnetic foreign matter is removed by changing the rotation speed of the housing according to the concentration of the magnetic foreign matter in the sample.

The sample is not particularly limited as a resin powder, for example, a resin of high-density polyethylene, low-density polyethylene, polypropylene, or polystyrene. The particle size of the resin powder is not particularly limited, but the average particle size is preferably 30 μm to 500 μm. The present invention is applied because the shape of the resin includes powder in the form of pellets or chips. The liquid is, for example, water, an aqueous solution, a viscous liquid, an organic solvent, or the like, and is not particularly limited.

The present invention is a step of kneading a polyolefin resin from which magnetic foreign substances have been removed using the above magnetic foreign matter removing device and a plastic agent from which magnetic foreign substances have been removed using the above magnetic foreign matter removing device to prepare a polyolefin solution. A step of discharging the polyolefin solution from the die and cooling it to obtain a gel-like sheet, a step of stretching the gel-like sheet to form a stretched sheet, and a step of removing the plasticizing agent from the stretched sheet to obtain a microporous film. It is a method for producing a microporous film, which comprises a step and a step of winding a microporous film around a core to obtain a film product reel.

This is a method for manufacturing a film product in which a slurry from which magnetic foreign substances have been removed is coated on a film using the above-mentioned magnetic foreign matter removing device.

According to the present invention, a magnetic foreign matter removing method and a magnetic foreign matter removing device capable of efficiently removing magnetic foreign matter from a sample with an inexpensive configuration, and a fine particle manufactured by using such a magnetic foreign matter removing device. It is an object of the present invention to provide a method for producing a porous film.

It is a triangular figure which shows one Embodiment of the magnetic foreign matter removing apparatus of this invention. It is an enlarged view which shows one Embodiment of the magnetic foreign matter removing apparatus of this invention. FIG. 1B is an enlarged view of the polygonal housing of FIG. 1B after being rotated by 180 °.

(Magnetic foreign matter remover)
Hereinafter, an example of the embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1A, the magnetic foreign matter removing device 1 in the present embodiment can rotate the rotating shaft 4 at the center of the polygonal prism housing 2, and the rotating shaft 4 is supported by the legs 6. The rotating shaft 4 is provided with a handle 5 and can be rotated manually. Further, the rotating shaft 4 can also be rotated by an electric motor.

The number of angles of the polygonal prism housing is not particularly limited, but if the number of angles is increased, the labor for welding when manufacturing the housing increases and the cost becomes high, which is not preferable. It is preferably 3 to dodecagonal.

As shown in FIG. 1B, a magnet plate 3 is provided on the side surface of the polygonal prism housing.

As shown in FIG. 1 (c), the magnet cover 7 is fitted to the magnet plate 3, and even if the sample contact surface of the magnet cover 7 is made uneven or designed to improve the efficiency of capturing magnetic foreign matter. good. However, if the shape is conspicuous like a magnet bar, the fluidity inside the housing is impaired, and the contact rate with the magnet may be impaired.

When cleaning the magnetic substance removing device 1, the magnet plate 3 can be removed from the magnetic substance removing device 1, and the magnet cover 7 can be removed from the magnet plate 3 for disassembly and cleaning. Since the magnet plate also serves as the lid of the housing, the magnet plate 3 can be cleaned when the sample is put into the magnetic substance removing device 1, and the work can be efficiently proceeded. After the sample is placed in the polygonal prism housing 2, the sample is repeatedly contacted with the magnet plate 3 by manually or electrically rotating the polygonal prism housing 2, thereby achieving removal of magnetic foreign matter. The magnet plate 3 is made of, for example, a 11000 gauss permanent magnet.

The concentration of magnetic foreign matter in the sample is confirmed in advance by visual inspection or inspection by equipment, and the rotation speed of the housing is determined according to the concentration of magnetic foreign matter in the sample. By rotating the housing at a predetermined rotation speed, 100% of magnetic foreign matter is removed.

(Manufacturing method of microporous membrane)
Next, a method for producing a microporous film using an olefin resin from which magnetic foreign matter has been removed by the above-mentioned magnetic foreign matter removing device and a plasticizer from which magnetic foreign matter has been removed by the above-mentioned magnetic foreign matter removing device will be described. When producing a polyolefin microporous membrane as a microporous membrane, first, a plasticizer such as liquid paraffin is added to the polyolefin resin, and these are melt-kneaded by a twin-screw extruder or the like to obtain a polyolefin solution. Then, the polyolefin solution is discharged using a base such as a T-type die and cooled by a cast cooling device or the like to obtain a gel-like sheet. A gel-like sheet is stretched in the mechanical direction (MD) and the width direction (TD) to obtain a stretched sheet, and then a plasticizer is dissolved and removed from the stretched sheet using a cleaning solvent or the like to obtain a microporous membrane film. A microporous film is obtained as a long film by performing it in a continuous process from the ejection of the polyolefin solution to the dissolution and removal of the plasticizer. Therefore, by winding this microporous film around the outer peripheral surface of the core. , Film product reels are obtained.

A film product is obtained by coating a film with a slurry from which magnetic foreign substances have been removed by the above-mentioned magnetic foreign matter removing device.

1 Magnetic foreign matter removal device 2 Polygonal prism housing 3 Magnet plate 4 Rotating shaft 5 Handle 6 Legs 7 Magnet cover

Claims (13)

A magnetic foreign matter removing method that can remove magnetic foreign matter in a sample with high efficiency by bringing the sample into contact with the magnet plate by repeatedly moving it relatively in a closed space equipped with a magnet inside the housing. The concentration of magnetic foreign matter in the sample is confirmed in advance by visual inspection or inspection by equipment, and the sample in the housing is brought into contact with the magnet plate by repeatedly moving relative to the magnetic foreign matter concentration in the sample. The method for removing magnetic foreign matter according to claim 1, which can remove magnetic foreign matter in a sample with high efficiency. The sample in the housing can be agitated by a rotary blade, and a magnet plate with a part or all of the side surface of the housing made of permanent magnets is provided to remove magnetic foreign matter of several tens of μm to several tens of mm from the sample. The method for removing magnetic foreign matter according to claim 1 or 2, wherein the method is characterized by. Equipped with a mechanism that applies vibration to the housing, the sample can be agitated by vibration, and a magnet plate with a part or all of the side surface of the housing made of permanent magnets is provided, and the magnetism of several tens of μm to several tens of mm from the inside of the sample. The magnetic foreign matter removing method according to claim 1 or 2, wherein the foreign matter is removed. Equipped with an air supply mechanism and an exhaust mechanism that put compressed air into the housing, the sample can be agitated by circulating air, and a magnet plate with a part or all of the side surface of the housing made of permanent magnets is provided. The method for removing magnetic foreign matter according to claim 1 or 2, wherein the magnetic foreign matter having a size of 10 μm to several tens of mm is removed. A housing made of polygonal pillars or cylinders that can be rotated around the center of the polygon as a rotation axis, and is equipped with a magnet plate in which part or all of the side surfaces of the polygonal pillar housing are made of permanent magnets. The method for removing magnetic foreign matter according to claim 1 or 2, wherein the magnetic foreign matter of several tens of mm is removed from μm. The method for removing magnetic foreign matter according to claim 6, wherein the side surface of the polygonal prism housing is 3 to dodecagonal. The method for removing magnetic foreign matter according to claim 6 or 7, which comprises a polygonal prism housing or a manual handle for rotating a cylinder. The method for removing magnetic foreign matter according to claim 6 or 7, further comprising an electric motor for rotating a polygonal prism housing or a cylinder. A step of preparing a polyolefin solution by kneading a polyolefin resin from which magnetic foreign substances have been removed by the method for removing magnetic foreign substances according to any one of claims 1 to 9 and a plasticizer.
A step of discharging the polyolefin solution from the die and cooling the solution to obtain a gel-like sheet.
A step of stretching the gel-like sheet to form a stretched sheet, and
A step of removing the plasticizer from the stretched sheet to obtain a microporous film, and
The process of winding the microporous membrane around the core to obtain a film product reel,
A method for producing a microporous membrane, including. A method for producing a slurry containing water, an aqueous solution, a viscous liquid, an organic solvent, and a filler from which magnetic foreign substances have been removed by the magnetic foreign matter removing device according to any one of claims 1 to 9. A method for producing a film coated with a slurry from which magnetic foreign substances have been removed by the method according to claim 11. A film production method in which a microporous membrane produced by the method according to claim 10 is coated with a slurry produced by the method according to claim 11.

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