Method for sterilizing a container and apparatus for sterilizing a container

Abstract

This invention provides a container sterilization method and apparatus that avoids or reduces the risk of disinfectant residue and achieves effective sterilization in a short time. One container sterilization method is for sterilizing the surface of a container or container preform, comprising: laser irradiation treatment, irradiating the container surface with a CO2 laser; and UV light irradiation treatment, irradiating the container surface with UV light.

Description

Technical Field

[0001] This invention relates to a container sterilization method and apparatus for sterilizing the surface of containers or container preforms. Background Technology

[0002] Conventionally, as a container sterilization method for sterilizing the surface of a container or container preform, it is known to use sterilization treatment using sterilizing agents such as hydrogen peroxide (for example, see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-202284 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in sterilization processes that utilize bactericides, there is a concern that bactericide residues may remain on the molded containers, thus requiring countermeasures to reduce the risk of residue.

[0008] Therefore, the present invention is an invention to solve these problems, and its object is to provide a container sterilization method and container sterilization device that avoids or reduces the risk of disinfectant residue with a simple structure and achieves effective sterilization in a short time.

[0009] Solution for solving the problem

[0010] One embodiment of the container sterilization method of the present invention is a container sterilization method for sterilizing the surface of a container or a container preform, comprising: laser irradiation treatment, irradiating the container surface with a CO2 laser; and UV light irradiation treatment, irradiating the container surface with UV light, thereby solving the problem.

[0011] In addition, another embodiment of the container sterilization method of the present invention is a container sterilization method for sterilizing the container surface or container preform, comprising: laser irradiation treatment, irradiating the container surface with a laser of infrared wavelength; and UV light irradiation treatment, irradiating the container surface with UV light, thereby solving the aforementioned problem.

[0012] Furthermore, one embodiment of the container sterilization device of the present invention is a container sterilization device for sterilizing the surface of a container or container preform, comprising: a laser irradiation unit for irradiating the container surface with a CO2 laser; and a UV light irradiation unit for irradiating the container surface with UV light, thereby solving the aforementioned problem.

[0013] In addition, another embodiment of the container sterilization device of the present invention is a container sterilization device for sterilizing the surface of a container or container preform, comprising: a laser irradiation unit for irradiating the container surface with a laser of infrared wavelength; and a UV light irradiation unit for irradiating the container surface with UV light, thereby solving the aforementioned problem.

[0014] In any of the above-mentioned container sterilization methods or containers sterilization devices, the irradiation area of ​​the CO2 laser in the laser irradiation treatment may overlap with the irradiation area of ​​the UV light in the UV light irradiation treatment.

[0015] In any of the above-described container sterilization methods or containers sterilization devices, UV laser may be irradiated during the UV light irradiation treatment.

[0016] In any of the above-described container sterilization methods or containers sterilization devices, the laser irradiation treatment and the UV light irradiation treatment may be implemented by mixing the CO2 laser and the UV laser and irradiating them from the same irradiation unit.

[0017] In any of the above-mentioned container sterilization methods or containers sterilization devices, the sterilization ability of the laser irradiation treatment against mold may be set to be higher than that of the UV light irradiation treatment against mold.

[0018] In any of the above-described container sterilization methods or containers sterilization devices, the sterilization ability of the laser irradiation treatment against spores may be set to be lower than that of the UV light irradiation treatment against spores.

[0019] In any of the above-described container sterilization methods or containers sterilization devices, a heat treatment may be further included, performed before or simultaneously with the laser irradiation treatment, wherein the sterilized area on the container surface formed by the laser irradiation treatment is heated in the heat treatment.

[0020] In any of the above-described container sterilization methods or apparatuses, the method may further include: heat treatment, heating the preform, which is the container preform, to the molding temperature at which it is formed into a PET bottle, the heat-treated preform, and subjecting it to the laser irradiation treatment and the UV light irradiation treatment, wherein the cumulative light intensity (mJ / cm²) of the CO2 laser at the mouth of the preform is [not specified]. 2 The cumulative light intensity (mJ / cm) of the CO2 laser in the main body of the preform is compared to that in the preform body. 2 Larger, and / or the cumulative amount of UV light at the opening of the preform (mJ / cm²) 2 The cumulative UV light intensity (mJ / cm) of the preform body is higher than that of the preform body. 2)big.

[0021] Invention Effects

[0022] In this invention, the risk of bactericide residue can be avoided or reduced with a simple structure, and effective sterilization can be achieved in a short time. Attached Figure Description

[0023] Figure 1 This is an explanatory diagram showing an aseptic filling system of a container sterilization device having one embodiment of the invention.

[0024] Figure 2 This is an illustrative diagram showing an example of CO2 laser and UV light irradiation schemes.

[0025] Figure 3 This is an explanatory diagram showing the results of a test used to confirm the bactericidal effect of CO2 laser irradiation.

[0026] Figure 4 This is an illustration showing the sterilization effect achieved through UV light irradiation.

[0027] Figure 5 This is a graph showing the absorbance of spores, molds, and PET resin relative to the wavelength of light. Detailed Implementation

[0028] Hereinafter, an aseptic filling system 10 according to one embodiment of the present invention will be described based on the accompanying drawings.

[0029] It should be noted that the terms "upstream" and "downstream" used in this specification refer to the upstream or downstream direction of the preform P or container in the conveying direction.

[0030] First, the aseptic filling system 10 is configured as a so-called in-line blow molding filling system for aseptically filling sterilized contents (especially liquid contents) into a sterilized container, such as... Figure 1 As shown, the aseptic filling system 10 includes: an aseptic forming device 20 for aseptically forming a container; and a filling device 60 for aseptically filling the container with contents.

[0031] The following description, based on the accompanying drawings, explains the constituent elements of the aseptic filling system 10.

[0032] First, the aseptic forming device 20 aseptically forms the sterilized containers that have undergone sterilization treatment, such as... Figure 1As shown, the aseptic molding apparatus 20 includes: an inlet 21 for feeding a preform P, which is a container preform such as a PET bottle; a blow molding turntable 22; an oven mechanism 30 for heating the preform P in an oven area A1 located downstream of the inlet 21; a preform conveying mechanism 40 for conveying the preform P; and a container sterilization device 50 for sterilizing the preform P.

[0033] like Figure 1 As shown, the inlet 21 is the part used to feed the preform P into the aseptic molding device 20 (aseptic filling system 10).

[0034] like Figure 1 As shown, the blow molding turntable 22 is located on the downstream side of the oven area A1 to perform aseptic blow molding on the preform P.

[0035] Specifically, the blow molding turntable 22 is configured as a turntable equipped with a blow molding machine (not shown), which performs biaxial stretch blow molding of containers such as PET bottles by blowing sterile air into a preform P heated to the molding temperature for sterile blow molding.

[0036] The molding area A3, equipped with a blow molding turntable 22, is covered by a chamber. Sterile air that passes through a HEPA filter is blown in from above by an FFU (Fan Filter Unit), thereby maintaining a sterile atmosphere and positive pressure.

[0037] In addition, the blow molding turntable 22, blow molding machine and other equipment located in the molding area A3 are sterilized to the end of the blow molding piping.

[0038] The preform P, which has been sterilized through sterilization treatment only in the preform stage, is transported to the forming area A3 for aseptic blow molding.

[0039] Therefore, aseptic blow molding is performed in the molding area A3 under sterile conditions. Thus, during the transport of the preform P and the blow-molded container in the molding area A3, it is not necessary to create a sterile air or sterilizing gas atmosphere in the vicinity of the transport path. Furthermore, it is not necessary to sterilize the blow-molded container.

[0040] The oven mechanism 30 performs a heating process to raise the temperature of the preform P (the main body P1) to the molding temperature during sterile blow molding in the blow molding turntable 22. The oven mechanism 30 has: an oven chamber 31 with an oven area A1 inside; and a plurality of heating heaters 32 configured as infrared heaters to raise the temperature of the preform P.

[0041] It should be noted that the oven mechanism 30 may also be equipped with a simple cover surrounding the oven instead of the oven chamber 31. Alternatively, the oven chamber 31 may not be provided.

[0042] It should be noted that the main body P1 of the preform P is the part that is placed inside the mold during aseptic blow molding and expands inside the mold, while the opening P2 of the preform P is the part that is placed outside the mold during aseptic blow molding and does not expand.

[0043] In addition, such as Figure 1 As shown, the transfer area A2 is the area downstream of the oven area A1 and upstream of the forming area A3. It is an area with a higher contamination level than the forming area A3 but a lower contamination level than the oven area A1.

[0044] The preform conveying mechanism 40 will transport the preform P fed from the inlet 21 to the blow molding turntable 22, such as... Figure 1 As shown, the preform conveying mechanism 40 includes: a conveyor 41, which mainly conveys the preform P in the oven area A1; and a plurality of turntables 42, which convey the preform P removed from the oven area A1 toward the blow molding turntable 22.

[0045] Turntables 42 transport preforms P in transfer areas A2 and forming areas A3. These turntables 42 have multiple grippers that hold the preforms P from the outer peripheral side. Ideally, the grippers are pre-sterilized by UV light irradiation or a sterilizing agent.

[0046] It should be noted that the conveying posture of the preform conveying mechanism 40 for the preform P can be any posture, such as upright, inverted (i.e., the downward state in which the opening P2 side of the preform P faces downward), or lateral (i.e., the lateral state in which the opening P2 side of the preform P faces to the side).

[0047] The aseptic forming apparatus 20 is configured to perform sterilization treatment by means of the container sterilization apparatus 50, etc., when filling the contents in the filling apparatus 60, so that the container is in a commercially sterile state (i.e., a state in which all microorganisms that are harmful to public health and can develop in the beverage under normal non-refrigerated storage / distribution conditions are killed).

[0048] In this embodiment, the sterilization process performed by the sterilization device 50, etc., is configured to not perform sterilization after aseptic blow molding (sterilization at the container stage is not required), but to complete the sterilization of the container only by sterilizing the preform at the preform stage before forming the container using aseptic blow molding (more specifically, in this embodiment, sterilization is completed before the transfer area A2, and the sterilized preform P is moved into the forming area A3). In other words, the container can be made commercially sterile by sterilizing the preform at the preform stage only. In other words, the container can be sterilized by sterilizing the bacteria (bacteria that can proliferate in the contents filled in the container, such as mold, general bacteria, spores, etc.) that are the targets of sterilization by sterilizing the preform at the preform stage only (on the entire outer surface including the inner and outer surfaces of the preform P).

[0049] It should be noted that the sterilization effect (sterilization ability, D) is expressed by the formula sterilization effect (D) = LOG((initial number of bacteria) / (number of surviving bacteria)). For example, when the number of bacteria is reduced from 100 to 10, LOG(100 / 10) = 1D.

[0050] The container sterilization device 50 is configured to sterilize the inner surface (inner surface of the main body P1 and outer surface of the opening P2) of the preform P in a region downstream of the oven region A1 and upstream of the blow molding turntable 22 (transfer region A2 in this embodiment). Figure 1 As shown, the container sterilization apparatus 50 includes: a laser irradiator 51, which serves as a laser irradiation unit, irradiates the container surface of the container or preform P with CO2 laser; a UV irradiator 52, which serves as a UV light irradiation unit, irradiates the container surface with UV light; and a heating unit (in this embodiment, an oven mechanism 30), which is disposed upstream of the laser irradiator 51 or in the same location, to heat the sterilized area on the container surface.

[0051] CO2 lasers are a type of gas laser that uses a mixture of nitrogen and helium in a carbon dioxide gas atmosphere. The laser beam is extracted by passing a discharge current through this gas mixture.

[0052] like Figure 1 As shown, the laser irradiator 51 irradiates the container surface of the preform P being transported by the turntable 42 with a CO2 laser in a region that is downstream of the oven region A1 and upstream of the blow molding turntable 22 (transfer region A2 in this embodiment). This sterilizes the container surface of the preform P.

[0053] like Figure 2As shown, the laser irradiator 51 includes: a laser oscillator 51a; and an irradiation section 51b for irradiating the CO2 laser oscillated by the laser oscillator 51a, which is composed of optical elements such as a lens, a reflector, a beam expander, and a beam shaper.

[0054] It should be noted that the laser irradiator 51 (and UV light irradiator 52) can also be placed inside the oven area A1 or upstream of the oven area A1. Alternatively, the laser irradiator 51 (and UV light irradiator 52) can be placed downstream of the blow molding turntable 22 to irradiate the molded containers with CO2 laser for sterilization.

[0055] like Figure 1 As shown, the UV light irradiator 52 supplies sterilizing fluid to the container surface of the preform P being transported by the turntable 42 in a region downstream of the oven region A1 and upstream of the blow molding turntable 22 (transfer region A2 in this embodiment), thereby sterilizing the container surface of the preform P.

[0056] Here, the term "UV light" as used in this specification includes, but is not limited to, conventional UV light that uses UV lamps (including low-pressure mercury lamps), xenon lamps (xenon flash lamps, xenon arc lamps), UV-LEDs, etc. as light sources (UV light source 52a), as well as UV lasers that convert YAG (Nd:YAG) lasers, which are solid-state lasers, into UV wavelengths through wavelength conversion technology, and UV lasers generated by using excimer lasers, which are gas lasers, as light sources.

[0057] like Figure 2 As shown, the UV light irradiator 52 has an irradiation section 51b, which is composed of optical elements such as lenses, mirrors, beam expanders, and beam shapers, for irradiating UV light emitted from the UV light source 52a. The irradiation section 51b is not necessary, and UV light can also be irradiated directly from the UV light source 52a.

[0058] The heating unit is implemented before or simultaneously with the laser irradiation treatment performed by the laser irradiator 51 (and the UV light irradiation treatment performed by the UV light irradiator 52). During the laser irradiation treatment (and the UV light irradiation treatment), the sterilized area is heated in such a way that it becomes the sterilized area on the surface of the container. In this embodiment, the oven mechanism 30 described above functions as a heating unit.

[0059] It should be noted that the specific design of the heating unit is not limited to the above. It can also consist of a heating heater, a supplier of warm water, steam, hot air, etc., which are separately arranged from the oven mechanism 30. In this case, the heating temperature of the sterilized area can be appropriately set to above 60°C, above 80°C, or above 100°C.

[0060] The filling device 60 is located downstream of the aseptic forming device 20, such as... Figure 1 As shown, the filling device 60 includes: a filling section 61, which serves as a filling unit for filling contents into a container; and a capping section 62, which is disposed downstream of the filling section 61 and has a sterilized cap attached to the opening of the container.

[0061] Each process in the filling device 60 is carried out in a sterile chamber inside it.

[0062] Furthermore, the container is kept sterile within the interval between the aseptic forming apparatus 20 and the filling apparatus 60. In other words, the container is kept sterile throughout the entire interval from the time the container is aseptically blow-formed by the blow forming turntable 22 until the contents are aseptically filled into the container in the filling section 61. In this embodiment, the sterility of the container is maintained within the entire interval by using a chamber to cover the above-mentioned interval.

[0063] Next, the container sterilization method using the container sterilization apparatus 50 of this embodiment will be described.

[0064] First, the container sterilization method of this embodiment includes: heat treatment, which is performed before or simultaneously with laser irradiation treatment; laser irradiation treatment, which irradiates the container surface with CO2 laser; and UV light irradiation treatment, which irradiates the container surface with UV light.

[0065] The laser irradiation treatment is a process in which CO2 laser is irradiated onto the surface of the container (in this embodiment, the entire surface including the inner and outer surfaces of the preform P) by a laser irradiator 51, and is carried out on the path between the inlet 21 of the aseptic filling device and the filling section 61 where the filling treatment is performed.

[0066] UV light irradiation treatment is a process in which CO2 laser is irradiated onto the surface of the container (in this embodiment, the entire surface including the inner and outer surfaces of the preform P) by a UV light irradiator 52, and is carried out on the path between the inlet 21 of the aseptic filling device and the filling section 61 where the filling treatment is performed.

[0067] It should be noted that UV laser irradiation is preferred in UV light irradiation treatment.

[0068] like Figure 2 As shown, preferably, the CO2 laser irradiation area on the container surface during laser irradiation treatment is set to overlap (at least partially) with the UV light irradiation area on the container surface during UV light irradiation treatment.

[0069] It should be noted that, as for specific solutions for laser irradiation treatment and UV light irradiation treatment, such as Figure 2As shown in (a), the irradiation section 51b of the laser irradiator 51 and the irradiation section 52b of the UV light irradiator 52 can be respectively provided so that the irradiation areas overlap. Furthermore, as shown in (a), Figure 2 As shown in (b), the irradiation areas can overlap by mixing the CO2 laser and the UV laser and irradiating them from the same irradiation sections 51b and 52b. Alternatively, UV light can be directly irradiated from the UV light source 52a without using the irradiation section 52b of the UV light irradiator 52.

[0070] Here, Figure 2 The attached figure shows a mixer for mixing CO2 laser and UV laser. Figure 2 The reference numeral Lc in the attached diagram indicates a CO2 laser. Figure 2 The figure shown in the diagram uses the symbol Lu to indicate a UV laser.

[0071] It should be noted that, in Figure 3 The example shown assumes that CO2 laser irradiation and UV light irradiation are performed simultaneously, but CO2 laser irradiation and UV light irradiation can also be performed at staggered times (CO2 laser irradiation before or after).

[0072] Furthermore, it is preferable to set the laser irradiation treatment and UV light irradiation treatment performed on the preform after heat treatment in the following manner: (for both the inner and outer surfaces of the preform P, or only for the inner or outer surface of the preform P) the cumulative light intensity (mJ / cm²) of the CO2 laser at the opening P2 of the preform. 2 The cumulative light intensity (mJ / cm²) of the CO2 laser in the main body P1 of the preform is compared to that in the preform body. 2 The cumulative amount of UV light (mJ / cm²) at the opening P2 of the preform, and / or at the opening P2 of the preform. 2 The cumulative UV light intensity (mJ / cm) compared to the preform body P1 2 )big.

[0073] Furthermore, in laser irradiation treatment, it is preferable to irradiate with a CO2 laser having a wavelength of 9μm (center wavelength of 9.0 to 9.9μm).

[0074] Furthermore, in laser irradiation treatment, it is preferable to irradiate the CO2 laser for a duration of less than 1 second. This significantly reduces the sterilization time of the container. Here, irradiation time refers to the time the sterilized area receives the CO2 laser.

[0075] Furthermore, in laser irradiation treatment, to achieve a good sterilization effect and avoid damage to the container surface being irradiated, it is preferable to use a cumulative CO2 laser intensity of 1600 mJ / cm² in the sterilized area of ​​the container surface. 2Above and 30000mJ / cm 2 The following methods are used to irradiate CO2 lasers.

[0076] In addition, CO2 lasers can be irradiated with either continuous wave or pulsed wave in laser irradiation.

[0077] The heat treatment is a process in which the sterilized area on the surface of the container, which is produced by laser irradiation, is heated by a heating unit. In this embodiment, the preform P is heated to the forming temperature during the container forming process by an oven mechanism 30, which serves as the heating unit.

[0078] It should be noted that the heat treatment is preferably set so that the temperature of the sterilized area on the surface of the container is above 120°C when the preform P after heat treatment is subjected to laser irradiation treatment.

[0079] Next, based on Figure 3 The experiment conducted to confirm the sterilization effect achieved by CO2 laser irradiation is described.

[0080] In this experiment, a 1.7 × 10⁻⁶ ohmmeter diameter circular area was first attached to a plate-shaped substrate material made of PET (polyethylene terephthalate). 3 CFU spores (Bacillus atrophaeus spores) and 1.2 × 10 3 After removing the mold (Aspergillus niger) conidia from CFU, the mold is dried in a clean room, thus preparing the substrate material for inoculation with spores and mold.

[0081] Then, in Figure 3 The prepared substrate material was irradiated with a CO2 laser under the conditions shown, and then the number of surviving bacteria on the substrate material was measured using the following conventional methods.

[0082] Method for determining the viable bacterial count: The above-mentioned matrix material, sterilized surfactant aqueous solution, and sterilized beads were added to a sterilized test tube. The test tube was then sealed with a sterilized cap. The viable bacteria in the surfactant aqueous solution were extracted by shaking and suspended in a sterile dilution solution. The bacterial count was determined at each dilution ratio on standard agar medium using membrane filtration. The viable bacterial count was determined by incubating the medium at 35°C for one week and counting the colonies that appeared according to the dilution ratio.

[0083] It should be noted that the diameter of the CO2 laser irradiation point on the substrate material surface is approximately 22 mm. Figure 5The “Φ5 output (W)” shown is the value obtained by measuring the amount of output (W) of the laser oscillator during the experiment that irradiates a circular area with a diameter of 5 mm inoculated with bacteria.

[0084] Furthermore, for the matrix materials of A-9 to 12, when irradiated with CO2 laser, the irradiated area of ​​the matrix material was heated by a heater in such a way that the irradiated area of ​​the matrix material was 120°C.

[0085] Furthermore, the CO2 laser irradiated in A-1 to A-12 is a continuous wave, and the output is adjusted by PWM control (frequency 5kHz). The CO2 laser irradiated in B-1 to A-3 and C-1 to A-7 is a pulsed wave with a frequency of 1kHz.

[0086] Furthermore, the CO2 lasers irradiated in A-1~12 and B-1~3 have a wavelength of 9μm (9.3μm), while the CO2 lasers irradiated in C-1~7 have a wavelength of 10μm (10.6μm).

[0087] Furthermore, in this experiment, an optical system was constructed using a laser oscillator and an illumination lens as the illumination part. Additionally, the "Φ5 output (W)" was measured using a power meter (UP55N-300F-H12-D0) manufactured by Gentec.

[0088] The following can be learned from the results of the above experiment.

[0089] That is, it can be seen that when the wavelength of the CO2 laser is in the 9μm band, the concentration is 1600 mJ / cm² within the irradiation time range of 0.02 seconds to 0.05 seconds. 2 The above (more preferably 3310 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0090] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band, the concentration is 3310 mJ / cm² within the irradiation time range of 0.05 seconds to 0.075 seconds. 2 The above (more preferably 3820 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0091] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band, the efficiency is 3820 mJ / cm² within the irradiation time range of greater than 0.075 seconds and less than 0.1 seconds. 2 The above (more preferably 6621 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0092] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band, the energy is 6621 mJ / cm² within the irradiation time range of greater than 0.1 seconds and less than 0.2 seconds. 2 The above (more preferably 7130 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0093] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band, the concentration is 7130 mJ / cm² within the irradiation time range of greater than 0.2 seconds and less than 0.5 seconds. 2 The above (more preferably 7894 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0094] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band, the concentration is 7894 mJ / cm² within the irradiation time range of greater than 0.5 seconds and less than 1.0 second. 2 The above (more preferably 10186 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0095] Furthermore, it is known that when the wavelength of the CO2 laser is in the 10μm band, the concentration is 5093 mJ / cm² within the irradiation time range of 0.05 seconds to 1.0 second. 2 The above (more preferably 10200 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0096] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band and the substrate material is heated, the efficiency is 400 mJ / cm² within the irradiation time range of 0.005 seconds to 0.01 seconds. 2 The above (more preferably 662mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0097] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band and the substrate material is heated, the efficiency is 662 mJ / cm² within the irradiation time range of 0.01 seconds to 0.03 seconds. 2 The above (more preferably 1986 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0098] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band and the substrate material is heated, the efficiency is 1986 mJ / cm² within the irradiation time range of 0.03 seconds to 0.05 seconds. 2 The above (more preferably 3310 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be achieved against mold.

[0099] Therefore, it can be seen that even if the irradiation time is set to less than 1 second (more than 0.025 seconds for heating without a substrate and more than 0.005 seconds for heating with a substrate), the mold can still be sterilized by appropriately setting the output of the CO2 laser.

[0100] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band, the concentration is 4966 mJ / cm² within the irradiation time range of 0.05 seconds to 0.075 seconds. 2 Under the above conditions, a good bactericidal effect can be achieved against Bacillus spores.

[0101] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band, the energy density is 4966 mJ / cm² within the irradiation time range of greater than 0.075 seconds and less than 0.1 seconds. 2 The above (more preferably 6621 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be obtained against Bacillus spores.

[0102] Furthermore, it is known that when the wavelength of the CO2 laser is in the 9μm band, the energy density is 6621 mJ / cm² within the irradiation time range of greater than 0.1 seconds and less than 1.0 seconds. 2 The above (more preferably 10186 mJ / cm) 2 Under the above conditions, a good bactericidal effect can be obtained against Bacillus spores.

[0103] Furthermore, it is known that when the wavelength of the CO2 laser is in the 10μm band, the concentration is 7639 mJ / cm² within the irradiation time range of 0.05 seconds to 1.0 second. 2 Under the above conditions, a good bactericidal effect can be achieved against Bacillus spores.

[0104] Therefore, it can be seen that even if the irradiation time is set to less than 1 second (more than 0.05 seconds), the CO2 laser output can be appropriately set to kill Bacillus spores.

[0105] Furthermore, a comparison between A-7 and A-9 shows that for spore-forming bacteria, heating the matrix material improves the sterilization effect.

[0106] Furthermore, it is known that neither continuous wave nor pulsed wave will have a significant impact on the sterilization effect.

[0107] Furthermore, it is known that the higher the output (Φ5 output) of the CO2 laser and the shorter the irradiation time, the smaller the cumulative light intensity can be used for sterilization.

[0108] It should be noted that, while the mechanism by which CO2 lasers achieve the excellent bactericidal effect described above may not be fully understood, it is based on... Figure 4 The absorbance of Bacillus atrophaeus, Aspergillus niger, and PET resin relative to the wavelength of light is shown. In the CO2 laser band, especially the 9μm band, Bacillus atrophaeus, Aspergillus niger, and PET resin all exhibit high absorbance. It can be assumed that the bacterial cells absorb CO2 laser light and are directly heated, damaging their DNA. Furthermore, the PET resin is also heated by the laser, indirectly heating the bacterial cells, thus resulting in excellent bactericidal effects. The absorbance was measured using a Fourier transform infrared spectrophotometer (FT / IR6700, Nippon Spectrophotometer Co., Ltd.) via the KBR pellet method.

[0109] In this embodiment, laser irradiation treatment by irradiating the container surface with CO2 laser and UV light irradiation treatment by irradiating the container surface with UV light are used. As a result, compared with the case where it is desired to kill both spores and molds by UV light irradiation or CO2 laser irradiation alone, it is possible to effectively kill both spores and molds with low output and short time. In addition, the device configuration of each irradiator can be simplified.

[0110] That is, assuming that in order to achieve a bactericidal effect equivalent to 6D against both spore-forming fungi and molds using only UV light irradiation, Figure 4 The chart shows that, in order to kill Bacillus spores, a concentration of 77 mJ / cm³ is required. 2 UV light (UV laser) irradiation is sufficient, but for mold sterilization, 619 mJ / cm² is required. 2 UV light (UV laser) irradiation. Here, if CO2 laser irradiation is also used, and the mold is sterilized by CO2 laser irradiation, then the UV light at 77 mJ / cm²... 2 The amount of light is sufficient.

[0111] It should be noted that, in Figure 4 In the chart shown in (a), the bactericidal effect achieved by UV laser is estimated based on the cumulative amount of UV laser light required to obtain a 2.0D bactericidal effect (a value obtained experimentally) for Bacillus spores. Furthermore, in Figure 4In the chart shown in (b), the sterilization effect achieved by UV laser is estimated based on the cumulative amount of UV laser light required to achieve a 2.5D sterilization effect for mold (a value obtained experimentally).

[0112] Furthermore, the aforementioned test refers to attaching 1.4 × 10⁻⁶ ppm of a substrate material made of PET (polyethylene terephthalate) in a sheet-like form. 2 CFU (Bacillus atrophaeus spores) and 4.3 × 10 3 After removing the CFU (Aspergillus niger) conidia, the substrate material was dried in a clean room to prepare for inoculation with spores and mold. The prepared substrate material was then irradiated with a UV laser with a center wavelength of 266 nm. Subsequently, the number of surviving bacteria on the substrate material was measured using the conventional methods described above.

[0113] from Figure 3 As shown in the chart, to achieve a bactericidal effect equivalent to 6D against Bacillus spores using UV laser irradiation, an estimated 77 mJ / cm² is required. 2 UV light (UV laser) irradiation; furthermore, to achieve a bactericidal effect equivalent to 6D against mold using UV laser irradiation, it is estimated that 619 mJ / cm² is required. 2 UV light (UV laser) irradiation.

[0114] It should be noted that, by ​ , 4 As can be seen from the sterilization effects shown, UV light (UV laser) irradiation has a superior sterilization effect on spores, and CO2 laser irradiation has a superior sterilization effect on molds. Therefore, from the viewpoint of suppressing the total output, it is preferable to set the laser irradiation treatment and UV light irradiation treatment in such a way that the sterilization ability (D) of the laser irradiation treatment on molds is higher than that of the UV light irradiation treatment on molds.

[0115] Furthermore, from the same point of view, it is preferable to set the laser irradiation treatment and UV irradiation treatment in such a way that the bactericidal ability (D) of laser irradiation treatment on spores is lower than that of UV light irradiation treatment on spores (D).

[0116] Furthermore, by employing sterilization achieved through CO2 laser irradiation and UV light irradiation, sterilization without the need for disinfectants is eliminated, or even when sterilization with disinfectants is used, the amount of disinfectant used can be reduced, thus lowering the risk of disinfectant residues remaining in the formed container.

[0117] In addition, it also has a heating treatment that is performed before or simultaneously with the laser irradiation treatment, in which the sterilization effect of the sterilized area on the container surface produced by the laser irradiation treatment can be further improved by heating the sterilized area on the container surface.

[0118] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention as described in the claims. Furthermore, the above embodiments and the following variations can be arbitrarily combined to construct a container sterilization method and a container sterilization apparatus 50.

[0119] Furthermore, in the above embodiments, it is assumed that the container sterilization method (container sterilization device 50) is configured to sterilize the container surface of the preform P, which is a container preform, but the specific scheme of the aseptic filling method (aseptic filling system 10) is not limited to the above method, and it can also be configured to sterilize the container surface of the formed container.

[0120] Furthermore, in the above embodiments, it is assumed that the container preform is a preform P and the container is a PET bottle. However, the specific solutions for the container preform and the container are not limited to this. For example, the container can also be a resin-coated can, a coated can, etc. In addition, the container preform can also be a sheet (e.g., a sheet formed by coating the surface of a paper base material with synthetic resin, or a sheet formed into a resin film). The container can also be a sheet container (e.g., a paper bag, a small bag) obtained by molding the sheet.

[0121] In this case, the sheet material, which is a preform of the container, or the sheet container, which is a container, is also subjected to laser irradiation treatment and UV light irradiation treatment.

[0122] Furthermore, in this case, during laser irradiation and UV irradiation, the irradiation point of CO2 laser and UV light can be set to a transversely elongated shape in which the transverse width of the sheet material, which is the preform of the container, is wider than the longitudinal width of the sheet material in the conveying direction, and CO2 laser and UV light are irradiated on the sheet material while it is being conveyed.

[0123] Furthermore, when the container surface is formed (or coated) with synthetic resins such as PET (polyethylene terephthalate), PP (polypropylene), or PE (polyethylene), to avoid damage to the container surface caused by CO2 laser, it is preferable to use a cumulative CO2 laser intensity of 30,000 mJ / cm² in the sterilized area of ​​the container surface. 2 The following methods are used to irradiate CO2 lasers.

[0124] Furthermore, in the above embodiments, the container sterilization device 50 was described assuming it includes a laser irradiator 51, a UV light irradiator 52, etc. However, as a component of the container sterilization device 50, a sterilization processor other than the laser irradiator 51 may also be provided. Examples include sterilization processors that sterilize by supplying sterilization fluids such as hydrogen peroxide (hydrogen peroxide aqueous solution), peracetic acid (peracetic acid aqueous solution), or water (warm water, steam) to the container or container preform surface; sterilization processors that sterilize by irradiating the container surface with an electron beam; and dust collectors that remove dust adhering to the preform P. It should be noted that when using water (warm water, steam) as the sterilization fluid, the risk of sterilizing agent residue remaining in the formed container can be eliminated.

[0125] Furthermore, in the above embodiments, it is assumed that CO2 laser with a wavelength of 9 μm (center wavelength of 9.3 μm to 9.6 μm, etc., with a center wavelength of 9.0 to 9.9 μm) is irradiated during laser irradiation. However, it is also possible to irradiate CO2 laser with other wavelengths, such as 10 μm (center wavelength of 10.2 μm, 10.6 μm, etc., with a center wavelength of 10.0 to 10.9 μm).

[0126] Furthermore, the wavelength of the UV light irradiated in the UV light irradiation process is preferably set to a center wavelength of 240–280 nm. In particular, when irradiating with a UV laser, the wavelength of the UV laser is preferably set to a center wavelength of 266 nm (for UV lasers that generate YAG (Nd:YAG) lasers using wavelength conversion technology) or a center wavelength of 248 nm (for UV lasers generated using an excimer laser as a UV light source). Additionally, in the case of a UV lamp (low-pressure mercury lamp), a center wavelength of 254 nm is preferably set; in the case of a xenon flash lamp, a center wavelength of 240–280 nm is preferably set; and in the case of a UV-LED, a center wavelength of 265 nm is preferably set.

[0127] Furthermore, in the above embodiments, it is assumed that the entire surface of the container or container preform, including the inner and outer surfaces, is irradiated with CO2 laser and UV light. However, it is also possible to irradiate only a portion of the container surface (e.g., only the inner surface, only the outer surface, only the inner surface of the opening, etc.) with CO2 laser and UV light.

[0128] Furthermore, while the above embodiments have described the sterilization of the container surface using CO2 laser irradiation, it is also possible to use infrared wavelength lasers (specifically, lasers with wavelengths from 0.78 μm to 1000 μm, including near-infrared, mid-infrared, and far-infrared wavelengths) instead of CO2 lasers to sterilize the container surface. Besides CO2 lasers, known lasers such as diode lasers, fiber lasers, YAG lasers, YVO4 lasers, and CO lasers can also be used.

[0129] Compared with known infrared lamps and heaters, infrared wavelength lasers have high directivity, which can concentrate the infrared rays on the target area for sterilization, resulting in high energy efficiency. In addition, due to the rapid rise in output at the start of irradiation, they have the advantage of being able to perform short-term on-off (ON-OF) control.

[0130] It should be noted that the specific scheme for the aseptic filling method / system using infrared wavelength laser is exactly the same as the aseptic filling method / system using CO2 laser described above, except that infrared wavelength laser is used instead of CO2 laser. Therefore, the specific description is omitted by replacing "CO2 laser" with "infrared wavelength laser" in the description of the aseptic filling method / system using CO2 laser described above.

[0131] In addition, the above-described aseptic filling method / system using infrared wavelength lasers may also be described as follows, but is not limited to the following.

[0132] (Note 1)

[0133] A container sterilization method is a container sterilization method for sterilizing the surface of a container or a container preform, characterized by comprising:

[0134] Laser irradiation treatment, wherein the surface of the container is irradiated with a laser of an infrared wavelength; and

[0135] UV light irradiation treatment, in which UV light is irradiated onto the surface of the container.

[0136] (Note 2)

[0137] The container sterilization method according to Appendix 1 is characterized in that,

[0138] The irradiation area of ​​the infrared wavelength laser in the laser irradiation process overlaps with the irradiation area of ​​the UV light in the UV light irradiation process.

[0139] (Note 3)

[0140] The container sterilization method according to Appendix 1 or Appendix 2 is characterized in that,

[0141] UV laser is irradiated during the UV light irradiation treatment.

[0142] (Note 4)

[0143] The container sterilization method according to Appendix 3 is characterized in that,

[0144] The laser irradiation process and the UV light irradiation process are implemented by mixing infrared wavelength laser and UV laser and irradiating them from the same irradiation site.

[0145] (Note 5)

[0146] The container sterilization method according to any one of Appendices 1 to 4 is characterized in that,

[0147] The laser irradiation treatment is set to have a higher bactericidal effect on mold than the UV light irradiation treatment.

[0148] (Note 6)

[0149] The container sterilization method according to any one of Appendices 1 to 5 is characterized in that,

[0150] The bactericidal ability of the laser irradiation treatment against Bacillus spores is set to be lower than that of the UV light irradiation treatment against Bacillus spores.

[0151] (Note 7)

[0152] The container sterilization method according to any one of Annexes 1 to 6 is characterized in that,

[0153] It also includes: a heat treatment, performed before or simultaneously with the laser irradiation treatment.

[0154] In the heat treatment, the sterilized area on the container surface formed by the laser irradiation treatment is heated.

[0155] (Note 8)

[0156] The container sterilization method according to any one of Annexes 1 to 7 is characterized in that,

[0157] It also includes: a heat treatment, heating the preform, which serves as the container preform, to the molding temperature at which it is molded into a PET bottle, which serves as the container.

[0158] The preform after heat treatment is subjected to laser irradiation and UV light irradiation.

[0159] The cumulative light intensity (mJ / cm²) of the infrared wavelength laser at the opening of the preform.2 The cumulative light intensity (mJ / cm²) of the laser at an infrared wavelength compared to the main body of the preform. 2 Larger, and / or the cumulative amount of UV light at the opening of the preform (mJ / cm²) 2 The cumulative UV light intensity (mJ / cm) of the preform body is higher than that of the preform body. 2 )big.

[0160] (Note 9)

[0161] A container sterilization device is a device for sterilizing the surface of a container or a pre-formed container, characterized in that it comprises:

[0162] A laser irradiation unit irradiates the surface of the container with a laser of infrared wavelength; and

[0163] The UV light irradiation unit irradiates the surface of the container with UV light.

[0164] Explanation of reference numerals in the attached figures

[0165] 10: Aseptic filling system;

[0166] 20: Aseptic forming device;

[0167] 21: Entrance;

[0168] 22: Blow molding turntable;

[0169] 30: Oven mechanism;

[0170] 31: Oven chamber;

[0171] 32: Heating heater;

[0172] 40: Preform conveying mechanism;

[0173] 41: Conveyor;

[0174] 42: Turntable;

[0175] 50: Container sterilization device;

[0176] 51: Laser irradiator (laser irradiation unit);

[0177] 51a: Laser oscillator;

[0178] 51b: Irradiation section;

[0179] 52: UV light irradiator (UV light irradiation unit);

[0180] 52a: UV light source;

[0181] 52b: Irradiation section;

[0182] 53: Mixer;

[0183] 60: Filling device;

[0184] 61: Filling section;

[0185] 62: Cover section;

[0186] P: Preform (Container Preform)

[0187] P1: The main body of the preform;

[0188] P2: The opening of the preform;

[0189] A1: Oven area;

[0190] A2: Transfer area;

[0191] A3: Molding area;

[0192] Lc: CO2 laser;

[0193] Lu; UV light.

Claims

1. A container sterilization method, which is a container sterilization method for sterilizing the surface of a container or a container preform, characterized in that, include: Laser irradiation treatment, wherein the surface of the container is irradiated with CO2 laser; as well as UV light irradiation treatment, in which UV light is irradiated onto the surface of the container.

2. The container sterilization method according to claim 1, characterized in that, The CO2 laser irradiation area in the laser irradiation process overlaps with the UV light irradiation area in the UV light irradiation process.

3. The container sterilization method according to claim 1, characterized in that, UV laser is irradiated during the UV light irradiation treatment.

4. The container sterilization method according to claim 3, characterized in that, The laser irradiation process and the UV light irradiation process are implemented by mixing the CO2 laser and the UV laser and irradiating them from the same irradiation site.

5. The container sterilization method according to claim 1, characterized in that, The laser irradiation treatment is set to have a higher bactericidal effect on mold than the UV light irradiation treatment.

6. The container sterilization method according to claim 1, characterized in that, The bactericidal ability of the laser irradiation treatment against Bacillus spores is set to be lower than that of the UV light irradiation treatment against Bacillus spores.

7. The container sterilization method according to claim 1, characterized in that, It also includes: a heat treatment, performed before or simultaneously with the laser irradiation treatment. In the heat treatment, the sterilized area on the container surface formed by the laser irradiation treatment is heated.

8. The container sterilization method according to claim 1, characterized in that, It also includes: a heat treatment, heating the preform, which serves as the container preform, to the molding temperature at which it is molded into a PET bottle, which serves as the container. The preform after heat treatment is subjected to laser irradiation and UV light irradiation. The cumulative light intensity (mJ / cm²) of the CO2 laser at the opening of the preform 2 The cumulative light intensity (mJ / cm) of the CO2 laser in the main body of the preform is compared to that in the preform body. 2 Larger, and / or the cumulative amount of UV light at the opening of the preform (mJ / cm²) 2 The cumulative UV light intensity (mJ / cm) of the preform body is higher than that of the preform body. 2 )big.

9. A container sterilization device for sterilizing the surface of a container or a pre-formed container, characterized in that, include: A laser irradiation unit irradiates the surface of the container with a CO2 laser. as well as The UV light irradiation unit irradiates the surface of the container with UV light.

10. A container sterilization method, which is a container sterilization method for sterilizing the surface of a container or a container preform, characterized in that, include: Laser irradiation treatment, wherein the surface of the container is irradiated with a laser of infrared wavelength; as well as UV light irradiation treatment, in which UV light is irradiated onto the surface of the container.

11. A container sterilization device, characterized in that, it sterilizes the surface of a container or a pre-formed container, and is used to sterilize the container surface. include: A laser irradiation unit irradiates the surface of the container with a laser of infrared wavelength; as well as The UV light irradiation unit irradiates the surface of the container with UV light.

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