JP2005212827A - High performance filter packing body sterilizing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high performance filter packing body sterilizing method capable of efficiently sterilizing even a relatively large product such as a high performance filter by projecting electron beams thereon. <P>SOLUTION: In the high performance filter packing body sterilizing method, a high performance filter with a filter pack consisting of filter elements folded in a zigzag manner and interval maintaining members for the filter elements fixed to a filter frame is packaged with a radiation-resistant bag, and the high performance filter is packed for each radiation-resistant bag with corrugated fiberboard to form a high performance filter packing body. Electron beams are projected to each face forming upstream and downstream openings of the high performance filter so as to be passed through along folding surfaces of the filter elements. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for sterilizing a high performance filter package that efficiently sterilizes a package of a high performance filter that can be applied in a biological clean room.

Conventionally, high-performance filters used in ventilation systems of medical-related biological clean rooms are required to be sterilized in addition to cleanliness. As a sterilization method for high-performance filters and indoor equipment installed indoors, formalin fumigation is common. However, since formalin is extremely toxic to the skin and mucous membranes, if the ventilation treatment after formalin fumigation is inadequate, formalin remains in the air filter and the formalin scatters during ventilation, causing the human body and the subject of the experiment. There was a problem of having a dangerous impact on animals.
For this reason, as a sterilization method other than formalin fumigation, a method of assembling and packing a high-performance filter in a sterilized environment using pre-sterilized materials can be considered, but it is practically impossible to adopt this method. It is.
In addition to formalin fumigation, for example, methods for irradiating gamma rays and methods for irradiating electron beams are disclosed as methods for sterilizing medical devices such as pharmaceutical containers (Patent Documents 1 and 2).
JP 2002-128155 A Japanese Patent Laid-Open No. 11-130172

However, in the sterilization method of Patent Document 1, since the dose rate of γ rays is low, it takes time for the treatment, and since it is exposed to γ rays for a long time, there is a possibility that materials such as filter media constituting the filter are deteriorated. there were. Further, since cobalt 60 as a radiation source is a radioactive substance, it must be notified to the Science and Technology Agency, and there is a restriction that the apparatus cannot be moved without permission.
Further, even when the electron beam is irradiated as in the sterilization method of Patent Document 2, when the product itself is small like a medical device, 250 pharmaceutical containers can be packed together and irradiated with the electron beam. There is little variation in the surface dose of each product. However, a relatively large product such as a high-performance filter, where each part is formed of a different material and has a complicated structure, the surface dose at each part of the product varies greatly, and is desired for the entire high-performance filter. There was a problem that the surface dose of the sterility assurance level could not be obtained.
Therefore, in view of the above problems, the present invention provides a method for sterilizing a high-performance filter package capable of efficiently sterilizing even a relatively large product such as a high-performance filter by irradiation with an electron beam. The purpose is to provide.

In order to achieve the above object, the high performance filter package sterilization method of the present invention fixes a filter pack comprising a filter medium folded in a zigzag shape and a spacing member for the filter medium to the filter frame as described in claim 1. The high-performance filter is wrapped in a radiation-resistant bag, and the high-performance filter is packaged together with the radiation-resistant bag in a corrugated cardboard to form a high-performance filter package, toward each of the upstream and downstream openings of the high-performance filter, An electron beam is irradiated so that it may pass along the folding surface of a filter medium.
The high performance filter package sterilization method according to claim 2 is the sterilization method of the high performance filter package body according to claim 1, wherein the surface dose of the high performance filter is 5.8 kGy or more. It is characterized by irradiating with an electron beam.
Further, the method for sterilizing a high performance filter package according to claim 3 is the method for sterilizing a high performance filter package according to claim 1 or 2, wherein the high performance filter is wrapped in a plurality of the radiation resistant bags, At least two or more openings of the radiation-resistant bag are fused.

According to the method for sterilizing a high-performance filter package of the present invention, the following effects can be obtained.
(1) To irradiate the electron beam so as to pass along the folding surface of the filter medium toward each surface of the upstream and downstream openings of the high-performance filter, a high-performance filter is configured by irradiation with a low-energy electron beam. Without deteriorating each material, it is possible to irradiate the entire high performance filter having a relatively large size and structure with an electron beam having a surface dose of a predetermined value or more.
(2) Since sterilization is performed in the final package form, after sterilizing by irradiating with an electron beam, the high-performance filter can be carried into the clean room in the packaged state, and the package body is opened in the clean room. By doing so, the high performance filter can be attached to the clean room in a sterilized state without being attacked by various bacteria.
(3) Formalin fumigation that is harmful to the human body is no longer necessary, and the effects of residual formalin on the human body and experimental animals are eliminated.
(4) When the electron beam is irradiated so that the surface dose of the high-performance filter is 5.8 kGy or higher, the sterility assurance level (Sterility Assurance Level) is SAL10 ^-3 , so it is installed in a biological clean room. A sufficient level of sterility assurance can be obtained as a high performance filter.
(5) In addition, when the high-performance filter is wrapped in a plurality of radiation-resistant bags and the ends of two or more radiation-resistant bags are fused to irradiate an electron beam, after the electron beam irradiation, various bacteria However, it is difficult to reach a high-performance filter, and a high level of sterility assurance can be maintained. In addition, when multiple high-performance filters are packaged, the packaging can be removed sequentially according to the loading environment at the time of use, and the high-performance filter can be loaded and installed in a clean room without polluting the environment. Can do.

  The high-performance filter of the present invention forms a filter pack by holding the interval of the filter media folded in a zigzag shape with a separator or ribbon as a spacing member, and a gasket is disposed between the filter pack and the filter frame. The end of the filter pack is fixed to the filter frame with a sealing material.

  As the filter medium, glass fiber filter paper or synthetic fiber filter paper made of ultrafine fibers having an average fiber diameter of 0.5 μm to 1.0 μm can be used. In particular, it is preferable to use glass fiber filter paper made of ultrafine fibers that are not easily affected by deterioration due to electron beam irradiation.

  As the interval holding member for holding the interval between the filter media, a separator made of metal such as aluminum or stainless steel, a separator made of synthetic resin such as polyester, polyethylene or polypropylene, a separator made of natural fiber such as paper or pulp, or the like can be used. A hot melt resin ribbon or the like can be used as the spacing member. In particular, as a separator used for a high-performance filter for biological clean rooms, it is preferable to use a paper separator that is excellent in chemical resistance and less affected by electron beam irradiation or an aluminum separator that is less affected by electron beam irradiation. .

  As the filter frame, a metal filter frame such as extruded aluminum or stainless steel, or a synthetic resin filter frame such as PVC can be used. In particular, it is preferable to use a metal filter frame that is not easily affected by deterioration due to electron beam irradiation. In addition, since an electron beam does not permeate | transmit the inside of a filter frame when a filter frame is thick, it is preferable that the thickness of a filter frame is about 1 mm-5 mm.

  As the gasket, a gasket made of a synthetic resin such as EPDM or chloroprene can be used, but as a gasket used for a high performance filter for biological clean room, an EPDM gasket having excellent chemical resistance is preferably used.

  The sealing material may be a urethane resin or chloroprene resin that is not easily deteriorated by electron beam irradiation.

  The high performance filter is packaged in a radiation resistant bag. As the radiation-resistant bag, a bag using a synthetic resin sheet in which heat-sealable polyethylene, polypropylene, high-strength polyester, high-strength polyethylene terephthalate, or the like is single-layered or laminated can be used. The thickness of the sheet is preferably 50 μm to 100 μm. This is because if the thickness of the sheet exceeds 100 μm, in addition to the problem of poor flexibility and difficulty in handling, the electron beam is difficult to transmit and the surface dose of the packaged high-performance filter may be reduced. In addition, if the thickness of the sheet is less than 50 μm, pinholes and the like are likely to occur due to impact during transportation, etc., and various bacteria may enter and the high-performance filter may be contaminated.

  In addition, it is preferable that a plurality of the radiation-resistant bags are stacked, the high-performance filter is packaged, and the openings of at least two or more radiation-resistant bags are fused. When packaged with multiple radiation-resistant bags, the radiation-resistant bags can be removed sequentially depending on the sterilization condition of the environment that has been carried in, and high-performance filters can be carried in and attached without polluting the environment. It is. In addition, if two or more ends of the radiation-resistant bags are fused, various germs do not enter the high-performance filter after the electron beam irradiation, and a sterilized state can be maintained.

  The high-performance filter is packaged in a radiation-resistant bag and then packed in cardboard to form a high-performance filter package. Although synthetic resin corrugated cardboard can be used, it is preferable to use paper corrugated cardboard which is not easily deteriorated by electron beam irradiation and is versatile.

  In the sterilization method of the present invention, the high-performance filter package is irradiated with an electron beam so as to pass along the folding surface of the filter medium toward the upstream and downstream surfaces of the high-performance filter. . By irradiating the electron beam in this way, it is possible to irradiate the electron beam having a surface dose at which the entire high-performance filter having a relatively large size and complicated structure has a sufficient sterility assurance level. In addition, since it is only necessary to irradiate the electron beam toward each of the upstream and downstream openings of the high-performance filter, it is necessary to irradiate the electron beam from three directions or six directions even for a relatively large product. In addition, the number of electron beam irradiations can be reduced.

First, before performing the method for sterilizing a high-performance filter package of the present invention, the surface dose is 10 kGy, 20 kGy, 30 kGy on each material (filter medium, gasket, sealant, separator, filter frame) constituting the high-performance filter. The electron beam was irradiated so as to be 40 kGy, and the following characteristics of each material after 1 day, 7 days, and 30 days were measured and evaluated to examine the influence of the electron beam irradiation. Tensile strength (Table 1) was measured by the method of MIL-F-51079C for a filter paper made of ultrafine glass fiber having a basis weight of 70 g / m ² , a thickness of 0.38 mm, and a vertical and horizontal dimension of 25 mm × 150 mm. Further, the hardness of the gasket (Table 2) was measured with a measuring instrument (GS-706) using the method of SRIS0101 for the gasket made of EPDM. For the sealing material, the hardness (Table 3) of the sealing material made of chloroprene resin and urethane resin was measured with a measuring instrument (GS-706) using the method of SRIS0101. Moreover, the separator observed the external appearance after electron beam irradiation about paper-made and aluminum-made separators. The filter frame observed the external appearance after electron beam irradiation about the aluminum filter frame. In addition, the electron beam adjusted to the voltage and current shown in Tables 1 to 3 is irradiated each time for each material placed on the transport cart conveyor passing at each speed shown in Tables 1 to 3, and the surface dose is 10 to 10. It was set to 40 kGy.

As is clear from the results shown in Tables 1 to 3, with the unirradiated filter medium and the filter medium when the electron beam is irradiated so that the surface dose is 10 to 40 kGy, 30 after the electron beam irradiation in the CD direction and the MD direction. Even after the passage of days, there was no significant difference in tensile strength, and it was confirmed that there was no deterioration of the filter medium after electron beam irradiation. In addition, in the case of an unirradiated gasket and sealing material, and the gasket and sealing material when the electron beam is irradiated so that the surface dose is 10 to 40 kGy, the gasket and sealing material are not changed even after 30 days have passed since the electron beam irradiation. There was no difference in hardness, and it was confirmed that the gasket and the sealing material were not deteriorated after the electron beam irradiation. In addition, the dispersion | variation in the numerical value at the time of each measurement of a gasket and a sealing material was in the error range.
Moreover, as for the separator, both the aluminum separator and the paper separator had no difference in appearance until 30 days as compared with each unirradiated separator after irradiation with the electron beam. Also about the filter frame, the aluminum filter frame irradiated with the electron beam compared with the unirradiated aluminum filter frame had no difference in appearance until 30 days.
As described above, even if the electron beam is irradiated so that the surface dose becomes 40 kGy, it is confirmed that the respective materials constituting the high-performance filter are not deteriorated even after 30 days have passed since the electron beam irradiation. did it.

An example of a method for sterilizing a high-performance filter packaged body in which a high-performance filter is packed using each of the materials will be described with reference to the drawings.
FIG. 1 is an exploded perspective view for explaining a packing state of the high-performance filter packing body of the present invention. As shown in FIG. 1, a paper separator 3 having a basis weight of 150 g / m ² and a thickness of 190 μm is formed with an interval of a filter medium 2 obtained by folding an ultrafine glass fiber filter paper having a basis weight of 70 g / m ² and a thickness of 0.38 mm in a zigzag shape. The filter pack 9 is formed by holding, an EPDM gasket 6 is disposed between the filter pack 9 and the filter frame 5, and both linear ends of the filter medium 2 folded in a zigzag shape are made of chloroprene resin. In addition, both ends of the zigzag shape orthogonal to the fold line are fixed to a filter frame 5 made of extruded aluminum having a thickness of 35 μm with a sealing material 4 made of urethane resin, and the length is 610 mm × width 610 mm × A high-performance filter 1 having a depth of 290 mm was obtained.
The high-performance filter 1 is packaged in a radiation-resistant bag 7, and then the radiation-resistant bag 7 and the other radiation-resistant bag 8 are double-packaged, and the openings of the radiation-resistant bags 7 and 8 are heat sealed. The high-performance filter package 10 was obtained by fusing by the above method and sealed with the fusing allowances 7a and 8a. The double-wrapped radiation-resistant bags 7 and 8 were made of a low-density polyethylene resin film having a thickness of 70 μm.
Next, the high performance filter package 10 was housed in the cardboard box 12, and the cardboard box 12 was sealed to obtain a high performance filter package 13 measuring 640 mm long × 620 mm wide × 310 mm deep.

Next, a method for irradiating the high performance filter package 13 with an electron beam will be described. Electron beam irradiation was performed at Nippon Electron Irradiation Service Co., Ltd.
FIG. 2 is a schematic diagram illustrating a state in which the high-performance filter package 13 of the present invention is irradiated with an electron beam. As shown in FIG. 2, the two high-performance filter packing bodies 13 are placed on a transport cart conveyor 14, and the transport cart conveyor 14 is moved under the electron beam irradiation device 15 at an arrow 17 at a speed of 13.5 m / min. 4.8 MeV of the high-performance filter so that it passes along the folding surface of the filter medium 2 toward one surface that becomes the upstream and downstream openings of the high-performance filter 1 in the packing body 13. The electron beam 16 was irradiated. Subsequently, the high performance filter package 13 was inverted and irradiated with the electron beam 16 in the same manner. The electron beam may be simultaneously irradiated on both surfaces that are upstream and downstream openings of the high-performance filter 1.

Furthermore, the electron dose of each part of the high-performance filter in the high-performance filter package irradiated with the electron beam in the above example was measured with FTR-125 (manufactured by Fuji Photo Film Co., Ltd.) which is a film dosimeter.
FIG. 3 is a schematic view showing the measurement site of the high-performance filter 1 irradiated with the electron beam, and the thicknesses of the positions A, B, D, and E at the upper and lower ends of the separator disposed on both sides of the high-performance filter 1 are shown. The surface doses at five locations in one row a, b, c, d, e and five rows in one row a, b, c, d, e in the thickness direction of the center of the separator disposed at the central portion of the high-performance filter 1 are described above. Measured with a dosimeter. Further, a row in the thickness direction in the center of one side plate of the filter frame 5 a. The surface doses at five locations b, c, d, and e were measured with the dosimeter. Furthermore, about the corrugated cardboard which packed the said high performance filter 1, the surface dose of one place of the center part of two surfaces irradiated with the electron beam was measured with the said dosimeter. The results are shown in Table 4.

Table As is clear from the results shown in 4, confirmed that the surface dose of more than 5.8kGy across high-performance filter 1 is irradiated, as a whole high efficiency filter, to become a SAL10 ^-3 sterility assurance level Was confirmed. According to the embodiment, the surface dose of more than 15.0kGy the high efficiency filter except filter frame has been irradiated, the filter pack portion which air passes, SAL10 ^-6 advanced of which are applied to the medical device It was confirmed that the level of sterility was guaranteed.

Next, the sterilized high-performance filter was subjected to a BI (Biological Indicator) test using bacteria actually. The BI test is a method for evaluating sterilization using an indicator bacterium (Bacillus pumilus) with a relatively strong radiation resistance attached to a film-like carrier.
Specifically, at the positions A, B, C, D, and E of each separator shown in FIG. 3, the electron beam 16 out of the five rows a, b, c, d, and e in the thickness direction is The carrier was affixed to the position e closest to the irradiated surface, and after the electron beam irradiation, the carrier was peeled off, the carrier was cultured by the following method, and the presence or absence of bacterial growth was examined.
As a bacterium, Bacillus pumilus ATCC # 27142 manufactured by Namsa was used, and this bacterium was attached to a carrier of 1.8 × 10 ⁶ Spores / Strip (Lot.PO1800, D value: 1.3 kGy) as a BI. As a product, BBL's tripty case soy broth (adjustment Lot. 030314B) was used. First, the medium was autoclaved and then cooled, and the BI was inoculated by 1 Strip / Tube. Subsequently, the culture medium inoculated with the BI was cultured at 32.5 ± 2.5 ° C. for 7 days, and then the culture medium was observed. If the growth of the fungus was observed with the naked eye, the result was positive. In addition, in order to confirm the performance and sterilization of the culture medium, the non-irradiated one as a positive target and the one subjected to the BI test by irradiating the electron beam twice as a negative target were similarly cultured. The results are shown in Table 5.

  As apparent from the results shown in Table 5, according to the method for sterilizing a high-performance filter package of the present invention, it was confirmed that bacteria were not actually growing on the high-performance filter 1.

The exploded perspective view explaining the packing state of the high performance filter package of the present invention Schematic explaining the state which irradiates the electron beam to the high performance filter package of this invention Schematic showing the measurement site of the high-performance filter irradiated with the electron beam of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High performance filter 2 Filter medium 3 Separator 4 Seal material 5 Filter frame 6 Gasket 7 Radiation-resistant bag 7a Fusion allowance 8 Radiation-resistant bag 8a Fusion allowance 9 Filter pack 10 High performance filter package 12 Corrugated cardboard box 13 High performance filter package 14 Transport cart conveyor 15 Electron beam irradiation device 16 Electron beam 17 Transport cart conveyor moving direction

Claims (3)

  A high-performance filter in which a filter pack made up of a zigzag filter medium and a spacing member for the filter medium is fixed to a filter frame is wrapped in a radiation-resistant bag, and the high-performance filter is packed together with the radiation-resistant bag in a cardboard box. A high-performance filter package, wherein the high-performance filter package is irradiated with an electron beam so as to pass along the folding surface of the filter medium toward each of the upstream and downstream openings of the high-performance filter. Sterilization method.   The method for sterilizing a high-performance filter package according to claim 1, wherein the electron beam is irradiated so that a surface dose of the high-performance filter is 5.8 kGy or more. The high performance filter package according to claim 1 or 2, wherein the high performance filter is wrapped in a plurality of the radiation resistant bags and at least two or more openings of the radiation resistant bags are fused. Sterilization method.

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