JP2015016654A - Filter decomposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter decomposition method where a laminated filter is easily decomposed.SOLUTION: A heat-fusible film 2 is softened or melted by heating a laminated filter 10 to a temperature higher than the melting point of a thermoplastic resin contained in the heat-fusible film 2. Then, a plurality of plate-like porous bodies 1 can be separated each other without removing the heat-fusible film from the laminated filter by applying external force so as to apply the force in a direction in parallel with the main surface 4 of the plate-like porous bodies to the laminated filter.

Description

  The present invention relates to a method for disassembling a filter provided with a plurality of flat porous bodies and a heat-fusible film.

2. Description of the Related Art Conventionally, in order to collect and adsorb an object to be filtered in a fluid such as a gas or a liquid, a non-woven fabric, a fabric such as a woven fabric or a knitted fabric, and a porous body such as a breathable porous film or a breathable foam are provided. A filter is being used.
And in order to improve the collection performance and adsorption | suction performance of a filter, the filter formed by laminating | stacking the porous body formed in flat form with each main surface facing each other is examined. As such a filter, for example, in Japanese Patent Application Laid-Open No. 2002-292218 (hereinafter referred to as Patent Document 1), a side surface of a plurality of laminated plate-like porous bodies that is substantially parallel to the stacking direction is thermally fused. A filter formed by heat sealing with an adhesive film is disclosed.

JP 2002-292218 A (Claims, Example 4, FIG. 3 and the like)

The inventors of the present application, like the filter disclosed in Patent Document 1, are filters in which a heat-fusible film is bonded to a side surface that is substantially parallel to the laminating direction in a plurality of laminated plate-like porous bodies (hereinafter referred to as a filter). , Sometimes referred to as a laminated filter), and used to remove the filtration object.
And in order to make it easy to dispose of the used multi-layer filter or to make it easy to test the multi-layer filter after use to the analyzer, the heat-sealable film is peeled off from the multi-layer filter to separate the flat porous bodies from each other. Thus, it was attempted to disassemble the multilayer filter. However, since the heat-fusible film is fused to the side surface of each flat plate-like porous body, it is difficult to peel off the heat-fusible film from the laminated filter, and it takes time to disassemble the filter. there were.

An object of the present invention is to provide a method for easily disassembling a multilayer filter.

The present invention
“A filter disassembly method,
The filter includes a plurality of flat porous bodies and a heat-fusible film,
The plurality of flat plate-like porous bodies are laminated so that their main surfaces face each other,
The heat-fusible film is fused to the side surface that is substantially parallel to the lamination direction in the plurality of laminated plate-like porous bodies,
Heating the filter to a temperature equal to or higher than the melting point of the thermoplastic resin contained in the heat-fusible film;
Disassembling the filter, by applying an external force to the filter so that a force acts in a direction parallel to the main surface of the flat plate-like porous body to separate the plurality of flat plate-like porous bodies in a stacked state Method. "
It is.

As a result of examining the decomposition method of the multilayer filter, the present inventors have determined that the multilayer filter is heated to a temperature equal to or higher than the melting point of the thermoplastic resin contained in the thermal sealable film, whereby the heat-fusible film is obtained. The heat-sealable film is removed from the laminated filter by applying an external force to the laminated filter so that a force acts in a direction parallel to the main surface of the plate-like porous body. Even if it does not do, it discovered that several flat porous bodies could be isolate | separated easily.

It is a typical perspective view of a multilayer filter. It is typical sectional drawing at the time of cut | disconnecting a laminated filter in the lamination direction of a flat porous body. It is typical sectional drawing at the time of cut | disconnecting another laminated filter in the lamination direction of a flat porous body. It is typical sectional drawing at the time of cut | disconnecting the filter cartridge which uses a laminated filter in the lamination direction of a flat porous body.

In order to explain the filter disassembling method of the present invention, the main aspect of the multilayer filter (10) according to the present invention is shown in FIG. Description will be made with reference to FIG. 2 which is a schematic cross-sectional view when cut in the direction.
The upstream side (A, hereinafter referred to as upstream side (A)) in the multilayer filter (10) is the upward direction on the paper surface, and the downstream side (B, hereinafter downstream side (B) in the multilayer filter (10). )) Is the lower side of the paper.

The multilayer filter (10) includes a plurality of flat porous bodies (1) and a heat-fusible film (2). The plurality of flat plate-like porous bodies (1) are laminated such that the main surfaces (3) face each other, and the plurality of laminated flat plate-like porous bodies (1, hereinafter referred to as a laminated body) may be referred to. ) In the laminating direction (vertical direction on the paper surface in FIG. 1-2), the heat-fusible film (2) is fused to the side surface (4) so that each flat porous body (1) The side surface (4) is fixed.

In the filter disassembling method of the present invention, first, the laminated filter (10) is heated to a temperature equal to or higher than the melting point of the thermoplastic resin contained in the heat-fusible film (2), and the heat-fusible film. (2) is softened or melted (hereinafter, this process may be referred to as a heating process).
Next, for the multilayer filter (10) subjected to the heating step, a direction parallel to the main surface (3) of the plate-like porous body (1) constituting the multilayer filter (10) (in FIG. 1-2, An external force is applied so that a force acts in the left-right direction on the paper surface (hereinafter, this step may be referred to as an external force application step).

In addition, the method of “applying an external force so that a force acts in a direction parallel to the main surface (3) of the plate-like porous body (1)” is appropriately selected as long as the multilayer filter (10) can be easily disassembled. For example, for the multilayer filter (10),
1. An external force is applied from the direction parallel to the main surface (3) of the plate-like porous body (1) constituting the multilayer filter (10) and / or
2. A method of applying an external force from a direction that is larger than 0 ° and smaller than 90 ° with respect to the parallel direction can be adopted.

By providing the multilayer filter (10) to the heating step, the heat-fusible film (2) fixing the side surface (4) of each plate-like porous body (1) can be softened or melted, By applying an external force to the multilayer filter (10) as described above, the plurality of plate-like porous bodies (1) can be bonded to each other without removing the heat-fusible film (2) from the multilayer filter (10). Can be easily separated.

Details of the multilayer filter (10) will be described below.

The plate-like porous body (1) is a sheet-like member made of a material having air permeability and liquid permeability such as a cloth such as a nonwoven fabric, a woven fabric, or a knitted fabric, and a breathable porous film or a breathable foam. is there. In addition, although a flat porous body (1) can be comprised from one type of raw material, you may comprise by combining several raw materials, such as laminating | stacking.

  The above-mentioned materials include, for example, polyolefin resins (polyethylene, polypropylene, polymethylpentene, polyolefin resins having a structure in which a part of hydrocarbon is substituted with a cyano group or a halogen such as fluorine or chlorine), styrene resins, and polyethers. Resin (polyether ether ketone, polyacetal, phenol resin, melamine resin, urea resin, epoxy resin, modified polyphenylene ether, aromatic polyether ketone, etc.), polyester resin (polyethylene terephthalate, polytrimethylene terephthalate, Polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate, polyarylate, wholly aromatic polyester resin, unsaturated polyester resin, etc.), polyimide Fat, polyamideimide resin, polyamide resin (for example, aromatic polyamide resin, aromatic polyetheramide resin, nylon resin, etc.), resin having nitrile group (for example, polyacrylonitrile, etc.), urethane resin, epoxy resin , Polysulfone resin (polysulfone, polyethersulfone, etc.), fluorine resin (polytetrafluoroethylene, polyvinylidene fluoride, etc.), cellulose resin, polybenzimidazole resin, acrylic resin (eg, acrylic ester or methacrylic ester) For example, polyacrylonitrile resins copolymerized with acrylonitrile and modacrylic resins copolymerized with acrylonitrile and vinyl chloride or vinylidene chloride).

These organic polymers may be either linear polymers or branched polymers, and the organic polymer may be a block copolymer or a random copolymer, and the three-dimensional structure or crystal of the organic polymer. The presence or absence of sex is not particularly limited. Furthermore, what mixed the some organic polymer may be sufficient, and it does not specifically limit.

Included in the material to prevent the flat porous body (1) from softening or melting when subjected to the heating process, and to easily separate the plurality of flat porous bodies (1) from each other in the external force application process The organic polymer has a melting point higher than the melting point of the thermoplastic resin contained in the heat-fusible film (2) and the melting point of the thermoplastic resin contained in the heat-fusible film (2). It preferably has a high pyrolysis temperature.

  When the material is a fabric, the fibers constituting the fabric are, for example, a melt spinning method, a dry spinning method, a wet spinning method, a direct spinning method (such as a melt blow method, a spun bond method, an electrostatic spinning method), or a composite fiber. It can be obtained by a known method such as a method of extracting fibers having a small fiber diameter by removing more than one kind of resin components, a method of beating fibers and obtaining divided fibers.

  The fibers constituting the fabric may be composed of one kind or plural kinds of resin components, and are generally called composite fibers, for example, core-sheath type, sea-island type, side-by-side type, orange type, etc. Can be used. In addition, the fabric may include a modified cross-section fiber.

Although the fiber diameter of the fiber which comprises a fabric is not specifically limited, It is preferable that the said fiber diameter is 0.01 micrometer-1 mm, and it is more preferable that it is 0.1 micrometer-100 micrometers. Moreover, although fiber length is not specifically limited, either short fiber, long fiber, or continuous fiber can be used.

When the fabric is a woven fabric or a knitted fabric, the material can be prepared by weaving or knitting the fibers prepared as described above.

When the fabric is a non-woven fabric, for example, a dry method or a wet method can be used as a method for preparing a fiber web capable of producing the non-woven fabric. And as a method of entanglement and / or integration of the fibers constituting the fiber web into a nonwoven fabric, for example, a method of entanglement with a needle or water flow, a method of integrating fibers with a binder, or a fiber web In the case where a thermoplastic resin is contained, there can be mentioned a method in which the fibers are integrated by melting the thermoplastic resin by heat-treating the fiber web.
In addition, as a method for heat-treating the fiber web, for example, a method of heating and pressurizing with a calender roll, a method of heating with a hot air dryer, a method of irradiating infrared rays under no pressure to melt thermoplastic resin fibers, etc. are used. it can. Moreover, you may prepare a nonwoven fabric by collecting the fiber spun using the direct spinning method.

When the material is a breathable porous film or a breathable foam, the material can be prepared by a known method such as casting a molten resin into a mold and performing foaming treatment.

Various characteristics such as the shape, basis weight, and thickness of the plate-like porous body (1) are not particularly limited and are preferably adjusted as appropriate. The shape of the plate-like porous body (1) may be, for example, an irregular shape or a polygonal plate shape other than the disk shape shown in FIG. The flat porous body (1) having such a shape can be obtained by cutting out or punching out the prepared material so as to have a desired shape. Basis weight of the plate-like porous body (1) is preferably from 1 to 500 g / ^{m 2,} more preferably from 3~300g / ^{m 2,} most preferably a 5 to 100 g / ^{m 2.} And it is preferable that the thickness of a flat porous body (1) is 0.01-30 mm, It is more preferable that it is 0.05-20 mm, It is most preferable that it is 0.1-10 mm.

In the present invention, “weight per unit area” refers to the mass per 1 m ² area of the main surface, and the main surface refers to a surface having a large area. The “thickness” as used in the present invention is a value measured by a compression elastic thickness gauge, and specifically, when a load of 100 gf is applied to a load area of 5 cm ² with respect to the main surface of the measurement object. Of the thickness of the region.

When imparting functionality to the multilayer filter (10) of the present invention, it is preferable that one or more flat porous bodies (1) constituting the multilayer filter (10) contain a functional component. The type of the functional component can be appropriately selected depending on the function required for the multilayer filter (10), and is not limited. For example, a radioactive substance adsorbent (for example, zeolite, activated carbon, Prussian blue, etc.) , Antibacterial agents, antiviral agents, antifungal agents, catalysts (such as titanium oxide, manganese dioxide, or platinum-supported alumina), humidity control agents (such as silica gel and silica microcapsules), deodorizers such as activated carbon and carbon black And dyes, flame retardants such as phosphoric acid flame retardants and aluminum hydroxide, deodorants, insect repellents, bactericides, fragrances, cation exchange resins and anion exchange resins.

And a functional component coat | covers a part (for example, fiber surface etc.) or all of the surface of a flat porous body (1) at the surface and / or inside of a particle form, or a flat porous body (1). It can exist in the form of a film. In particular, when a particulate functional component (hereinafter, sometimes referred to as functional particle) is used, the functional particle can be present in the pores existing in the flat plate-like porous body (1). A multilayer filter (10) having excellent properties can be provided, which is preferable.

The shape of the functional particles can be adjusted as appropriate, and can be appropriately selected from, for example, spherical (substantially spherical or true spherical), fibrous, needle-like, flat-plate, irregular shape, polyhedral shape, feather shape, and tetrapod shape. The diameter of the functional particles can also be adjusted as appropriate, but functional particles having a diameter in the range of micrometer order (1 μm or more and less than 1 mm) are preferable so that the functionality is efficiently exhibited. Functional particles having a diameter in the order (1 nm or more and less than 1 μm) range are more preferable.

The diameter of the functional particles in the present invention refers to an electron micrograph of the functional particles or an electron micrograph of the main surface of the plate-like porous body (1) provided with the functional particles. It can be obtained by measuring. In addition, when the shape of the functional particle shown in the electron micrograph is non-circular, the diameter of a circle having the same area is regarded as the diameter of the functional particle.
In addition, when the diameter of the functional particles cannot be measured from the electron micrograph by the above-described method, for example, the particle diameter is too small, the functional particles to be measured are FPRA1000 (measurement range: 3 nm to 3 nm). The value obtained from the particle diameter measurement data obtained from the scattering intensity is regarded as the diameter of the functional particle. That is, continuous measurement is performed three times, and the average value of the average particle diameter calculated by the cumulant method is set as the diameter of the functional particles. In addition, the measurement liquid used for the measurement is adjusted to a temperature of 25 ° C., and pure water at 25 ° C. is used as a blank for scattering intensity.

The method for preparing the plate-like porous body (1) provided with the functional component can be appropriately selected and is not limited. For example, the following method can be adopted.
1. A method of preparing the plate-like porous body (1) using the material prepared by mixing the organic polymer and the functional component described above and prepared from the mixed organic polymer,
2. A method for preparing a flat porous body (1) using a fabric prepared by mixing fibers and functional particles,
3. A method for preparing a flat porous body (1) using a melted functional component, a solution of a functional component, or a material provided with a dispersion of functional particles;
4). A method of preparing a plate-like porous body (1) using a material to which functional particles are bonded using a binder;
5. A functional porous particle heated to a temperature equal to or higher than the melting point of the thermoplastic resin constituting the raw material is brought into contact with the prepared raw material, and a flat porous body (1) is prepared using the material on which the functional particles are welded and supported. how to,
Or
1. A method of applying a molten functional component, a solution of a functional component, or a dispersion of functional particles to the plate-like porous body (1),
2. A method of bonding functional particles to the plate-like porous body (1) using a binder;
3. A method in which functional particles heated to a temperature equal to or higher than the melting point of the thermoplastic resin constituting the flat porous body (1) are brought into contact with the flat porous body (1), and the functional particles are welded and supported;
And so on.

In order to prevent the functional component from falling off, the raw material or the flat porous body (1) provided with the functional component prepared as described above is preferably subjected to a drop-off preventing treatment. The method for preventing the drop-off treatment is appropriately selected and is not limited, and examples thereof include a method for treating the drop-off prevention agent on the material having a functional component and the flat porous body (1).
In order to prevent the functional particles from falling out of the flat porous body (1) having functional particles to the outside of the multilayer filter (10), the average pore diameter is smaller than the particle diameter of the functional particles. The flat plate-like porous body (1) having the pores is preferably a laminated filter (10) formed adjacent to the flat-plate-like porous body (1) having functional particles.

The mass of the functional component included in the flat porous body (1) is appropriately adjusted and is not limited, but is preferably 0.01 to 300 g / m ² , and preferably 0.05 to 200 g / m ^2. m ² is more preferable, and 0.1 to 100 g / m ² is most preferable.

If the heat-fusible film (2) contains a thermoplastic resin and can be fused to the side surface (4) of the laminate to fix the side surface of each plate-like porous body (1), its composition and mode Can be appropriately selected and prepared. The kind of the thermoplastic resin contained in the heat-fusible film (2) is not limited. For example, among the organic polymers cited as being capable of constituting the plate-like porous body (1), the thermoplastic resin is 1 It can be configured by using types or by mixing a plurality of types.
The ratio of the thermoplastic resin contained in the heat-fusible film (2) is adjusted as appropriate so that the above-described effects can be exhibited, but in order to easily fix the side surface of each flat porous body (1), And / or in order to make it easy to separate the plurality of plate-like porous bodies (1) from each other in the external force acting step, which will be described later, it is preferable that the heat-fusible film (2) is composed only of the thermoplastic resin. .

In addition, when the heat-fusible film (2) contains a plurality of types of thermoplastic resins, the melting point of the thermoplastic resin having the lowest melting point among the plurality of types of thermoplastic resins is set to the heat-fusible property. It is regarded as the melting point of the thermoplastic resin contained in the film (2).

The shape of the heat-fusible film (2) is only required to be adjusted so that the entire side surface (4) of the laminate can be fixed by the heat-fusible film (2). Or a cylindrical shape.
When the shape of the heat-fusible film (2) is long, the length of the short side is equal to or longer than the length in the laminating direction of the flat plate-like porous body (1) so that the fixing is performed. Preferably, the length of the long side is not less than the length on the side surface (4) orthogonal to the stacking direction in the stacked body. Moreover, when the shape of the heat-fusible film (2) is cylindrical, the inner diameter of the cylindrical heat-fusible film (2) is larger than the diameter of the laminate so that the fixing is performed. Preferably, the length of the cylindrical heat-fusible film (2) in the direction perpendicular to the inner diameter (the height of the cylindrical heat-fusible film (2)) is the lamination direction of the laminate. It is preferable that it is more than this length.

The basis weight and thickness of the heat-fusible film (2) are appropriately adjusted and are not limited, but the basis weight of the heat-fusible film (2) is 5 to 200 g / m ² . it is preferred, more preferably from 10 to 150 g / ^{m 2,} most preferably a 20 to 100 g / ^{m 2.} The thickness of the heat-fusible film (2) is preferably 1 to 300 μm, more preferably 5 to 200 μm, and most preferably 10 to 100 μm.

The method for preparing the multilayer filter (10) of the present invention is appropriately selected and is not limited. For example, it can be prepared by the method described below.

First, a plurality of plate-like porous bodies (1) are simply overlapped, a plurality of plate-like porous bodies (1) are bonded and integrated using a binder, a hot melt nonwoven fabric, or the like, or a plate-like porous body (1). A laminated body is prepared by, for example, melting the organic polymer that constitutes and bonding and integrating the plurality of plate-like porous bodies (1).
Then, when the shape of the heat-fusible film (2) is long, the long heat-fusible film (2) is wound around the entire side surface (4) of the laminated body, and the laminated body The entire side surface (4) is covered with a heat-fusible film (2). At this time, a portion where the heat-fusible films (2) overlap each other may be formed, and if necessary, the portion may be integrated by a binder or heat bonding.
Alternatively, when the shape of the heat-fusible film (2) is cylindrical, the laminate is placed in the internal space of the cylindrical heat-fusible film (2), and the entire side surface (4) of the laminate is obtained. Is covered with a heat-fusible film (2).
And the laminated body with which the whole side surface (4) was covered with the heat-fusible film (2) is provided to heat processing. The method of heat treatment is appropriately selected so that the multilayer filter (10) of the present invention is formed. For example, a method of supplying to a hot air dryer, a method of irradiating infrared rays under no pressure, a method of applying hot air Then, the heat-fusible film (2) is softened or melted, and then the softened or melted heat-fusible film (2) is pressed, and the side surface of each flat porous body (1) is heat-fusible film. Fix in (2).

Alternatively, the heat-sealable film (2) softened or melted in advance is pressed against the entire side surface (4) of the prepared laminate, and the side surface (4) of each plate-like porous body (1) is heat-sealed. Fix with the adhesive film (2).

As shown in FIG. 1-2, the heat-fusible film (2) is exposed on the upstream side (A) and the downstream side (B) in addition to the side surface (4) of the laminate. When the peripheral part of the main surface of the porous body (1) is fixed, the plurality of flat plate-like porous bodies (1) tend to be fixed more reliably, which is preferable.
At this time, although the fixed length in the peripheral part is prepared suitably, it is preferable that it is 1-20% of length with respect to the diameter of a laminated body. In FIG. 2, the fixed length at the peripheral edge is illustrated as an arrow line length C.

The multilayer filter formed by fixing the peripheral part of the main surface of the flat porous body (1) exposed on the upstream side (A) and the downstream side (B) to the heat-fusible film (2) as described above. (10) is a state in which the heat-sealable film (2) that has been softened or melted is protruded from the side surface (4) of the laminate to the laminating direction, and the protruding portion is exposed in the form of a flat plate It can be prepared by pressing against the main surface of the porous body (1).

  The aspect of another laminated filter (20) is demonstrated using FIG. 3 which is typical sectional drawing when another laminated filter is cut | disconnected in the lamination direction of a flat porous body. Another laminated filter (20) is covered with a heat-shrinkable film (5) in which the side surface (4) of the laminated filter (10) is thermally shrunk through a heat-fusible film (2).

The term “heat-shrinkable film” as used herein refers to a shrinkage ratio of 20% or more measured based on the method described in “6. Test” of JIS Z 1709-1995 (measurement temperature: 120 ° C.). Refers to film. When the direction parallel to the film processing flow in the film is unknown, the shrinkage rate in the direction showing the highest shrinkage rate when the film is subjected to the above-described method is regarded as the shrinkage rate of the film. And the kind of organic polymer which comprises a heat-shrinkable film will not be limited if the heat-shrinkable film provided with the shrinkage | contraction rate mentioned above can be prepared, for example, it can comprise a flat porous body (1) It can comprise using the organic polymer quoted as.

The method for heat shrinking the heat-shrinkable film is appropriately selected, and the method disclosed in the heat treatment described above can be employed. Further, even if the heat-fusible film (2) is softened or melted by heat treatment and at the same time the heat-shrinkable film is heat-shrinked to prepare another laminated filter (20), the side surface of the laminated filter (10) ( 4) may be covered with a heat-shrinkable film, followed by heat treatment to heat-shrink the heat-shrinkable film to prepare another multilayer filter (20).
In another laminated filter (20), the heat-fusible film (2) is pressed against the side surface (4) of the laminated body by the heat-shrinkable heat-shrinkable film (5). 1) tends to be reliably fixed with the heat-fusible film (2), which is preferable.

When preparing another laminated filter (20), the direction of the highest shrinkage in the heat-shrinkable film is parallel to the laminating direction of the plate-like porous body (1). If prepared, the plurality of flat plate-like porous bodies (1) tend to be more reliably fixed with the heat-fusible film (2), which is more preferable.

  The multilayer filter (10) prepared as described above or another multilayer filter (20) can be used as it is, but the multilayer filter (10) or another multilayer filter (20) is contained in the frame (6). It can also be used as a filter cartridge (30). As an embodiment of the filter cartridge (30), a filter cartridge using a laminated filter will be described with reference to FIG. 4 which is a schematic cross-sectional view when cut in the laminating direction of a flat porous body.

  The filter cartridge (30) illustrated in FIG. 4 has a multilayer filter (10) housed in a frame (6) having an inlet (7) at one end and an outlet (8) at the other end. The filter cartridge (30).

The shape of the frame (6) can be selected as appropriate. For example, the frame (6) can have a cylindrical shape in which the multilayer filter (10) can be accommodated. For example, a PVC pipe or a plastic container can be used. When the multilayer filter (10) is housed in the frame (6), a gap is generated between the multilayer filter (10) exposed on both ends of the frame (6) and the frame (6), and leakage occurs. May occur. In order to fill the gap, it is preferable to seal between the multilayer filter (10) and the frame (6) using, for example, a hot melt resin.
The number of multilayer filters (10) housed inside the frame (6) can be adjusted as appropriate. Even if a pre-filter is provided upstream from the multilayer filter (10) housed inside the frame (6), A backup filter may be provided.

A method for disassembling the multilayer filter (10) will be described below.
In the method for disassembling the multilayer filter (10) of the present invention, when the multilayer filter (10) to be disassembled is housed in the frame (6), first, the multilayer to be disassembled from the frame (6). Remove the filter (10). Moreover, when the side surface (4) of the multilayer filter (10) is covered with the heat-shrinkable film (5) that has been heat-shrinked, it is preferable to remove the heat-shrinkable film (5).
Then, the multilayer filter (10) to be decomposed is subjected to a heating step and then to an external force application step, whereby the plurality of plate-like porous bodies (1) are separated to decompose the multilayer filter (10).

The method of heating the multilayer filter (10) is appropriately selected. For example, a method of supplying to a hot air dryer, a method of irradiating infrared rays under no pressure, a method of applying hot air, such as a plate heater or a mantle heater A method of contacting the heater can be employed.
The temperature at which the multilayer filter (10) is heated may be a temperature equal to or higher than the melting point of the thermoplastic resin contained in the heat-fusible film (2), and is appropriately prepared depending on the melting point of the thermoplastic resin. However, in order to easily separate the plurality of plate-like porous bodies (1) from each other, heating is performed under conditions that are equal to or higher than the melting point of any thermoplastic resin constituting the heat-fusible film (2). Is most preferred.

In addition, although the upper limit of heating temperature is adjusted suitably, it prevents that a flat porous body (1) softens or melt | dissolves, and when it uses for an external force action process, several flat porous bodies (1) are easily connected. In order to facilitate separation, heating is preferably performed under conditions that are lower than the melting point of the organic polymer contained in the material constituting the flat porous body (1) and lower than the thermal decomposition temperature. .

  A method of applying an external force to the multilayer filter (10) after being subjected to the heating step is appropriately selected. For example, a method of applying pressure by hand, a method of applying pressure using a tool, etc. It is possible to adopt a method in which a clamping pressure is applied with a jig such as a flat plate. The strength of the external force at this time is appropriately adjusted so that a plurality of flat plate-like porous bodies (1) can be separated from each other, but the flat plate-like porous body (1) is not destroyed by the action of the external force. It is preferable to adjust so that the filtration object collected by the porous body (1) does not fall off.

In the laminated filter (10) after being subjected to the heating step, the heat-fusible film (2) is provided so that the plurality of plate-like porous bodies (1) can be easily separated from each other and the laminated filter (10) can be decomposed. It is preferable to apply an external force while the thermoplastic resin contained in (2) is heated to a temperature equal to or higher than the melting point.

According to the present invention, a method for easily disassembling a multilayer filter can be provided.
The inventors of the present application prepared a sample by mixing each plate-like porous body separated from the used multilayer filter, and provided the sample to the analyzer to collect and adsorb on the used multilayer filter. It was considered that the concentration of the filtered object (measuring object) can be accurately measured by the analyzer.

Therefore, for example, radioactive materials present in various fluids such as agricultural water, water used in plant factories, wastewater generated during decontamination of radioactive materials, industrial water, etc. are collected or adsorbed on the multilayer filter according to the present invention, Next, a sample obtained by mixing the separated flat plate-like porous bodies can be prepared by decomposing the laminated filter on which radioactive material is collected or adsorbed using the method for decomposing a filter of the present invention. And the radioactive substance can be accurately monitored by supplying the prepared sample to a radioactive substance analyzer such as a germanium semiconductor detector.

DESCRIPTION OF SYMBOLS 10 ... Multilayer filter 1 ... Flat porous body 2 ... Heat-sealable film 3 ... Main surface 4 of flat porous body ... Side surface 20 ... Another laminated filter 5 ... Heat-shrinkable heat-shrinkable film 30 ... filter cartridge 6 ... frame 7 ... inlet 8 ... outlet A ... upstream side B in laminated filter ... downstream side C in laminated filter ... Fixed length at the periphery

Claims (1)

A method of disassembling a filter,
The filter includes a plurality of flat porous bodies and a heat-fusible film,
The plurality of flat plate-like porous bodies are laminated so that their main surfaces face each other,
The heat-fusible film is fused to the side surface that is substantially parallel to the lamination direction in the plurality of laminated plate-like porous bodies,
Heating the filter to a temperature equal to or higher than the melting point of the thermoplastic resin contained in the heat-fusible film;
Disassembling the filter, by applying an external force to the filter so that a force acts in a direction parallel to the main surface of the flat plate-like porous body to separate the plurality of flat plate-like porous bodies in a stacked state Method.

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